APPARATUS AND METHOD FOR CONTINUOUS EXTRUSION
United States Patent 3740985
Four trains of gripping element quadrants are continuously propelled around four endless paths, meeting along one length of travel common to the four paths and cooperating along said common length of travel to form a continuously moving train of centrally apertured gripping elements moving toward an extrusion die adjacent the end of said common length of travel. Rod of indefinite length, coated with shear transmitting medium and extending into the central apertures of the gripping elements, is drawn along the common length of travel by means of shear forces generated in said coating by said gripping elements and transmitted to said rod as viscous drag force along the surface of the rod. Axial and normal stresses are built up in the rod to stress the rod far above its yield strength and increase its ductility, or capacity for deformation without fracture. In this state, the rod is moved through and deformed by the die. A pressure cylinder surrounds the gripping elements along the common length of travel and provides balanced increasing lateral support to the gripping elements as they move toward the die.
US Patent References:
Drawbench
Offutt - May 1952 - 2598190
Apparatus for cold reducing metal bars
Fisk - June 1953 - 2642280
/1321729.html
Friel - November 1919 - 1321729
Rib curving machine
Thompson - September 1951 - 2569266
ENDLESS TRACK DEVICES FOR LAYING CABLES AND THE LIKE
Courret - November 1971 - 3618840
Drawbench
Offutt - May 1952 - 2598190
Apparatus for cold reducing metal bars
Fisk - June 1953 - 2642280
/1321729.html
Friel - November 1919 - 1321729
Rib curving machine
Thompson - September 1951 - 2569266
ENDLESS TRACK DEVICES FOR LAYING CABLES AND THE LIKE
Courret - November 1971 - 3618840
Application Number:
05/199542
Publication Date:
06/26/1973
Filing Date:
11/17/1971
View Patent Images:
Export Citation:
Assignee:
Western Electric Company, Incorporated (New York, NY)
Primary Class:
Other Classes:
72/270, 72/284, 226/172
International Classes:
B21C1/26; B21C1/30; B21C23/00; B21C23/08; B21C23/21; B21C1/16; B21C23/02; B21C33/00
Field of Search:
72/60,45,284,270,422 226/172
US Patent References:
| 3417589 | Process and apparatus for working metals under high fluid pressure | December 1968 | Bobrowsky |
Primary Examiner:
Herbst, Richard J.
Claims:
What I claim is
1. Method for continuously deforming an elongated workpiece of indefinite length to produce an elongated product of indefinite length, said method comprising:
2. Method as in claim 1, further comprising:
3. Method as in claim 1, further comprising:
4. Method as in claim 2, further comprising:
5. Method for continuously deforming an elongated workpiece of indefinite length to produce an elongated product of indefinite length, said method comprising:
6. Method as in claim 5, further comprising:
7. Method as in claim 5, further comprising:
8. Method as in claim 6, further comprising:
9. Method as in claim 5, further comprising:
10. Method as in claim 5, further comprising:
11. Method for continuously deforming an elongated workpiece to produce an elongated product, said method comprising:
12. Method as in claim 11, wherein:
13. Method as in claim 12, wherein:
14. Method as in claim 11, wherein:
15. Method as in claim 14, wherein:
16. Method as in claim 11, wherein:
17. Method as in claim 16, wherein:
18. Method as in claim 16, wherein:
19. Method as in claim 11, wherein:
20. Method for continuously deforming an elongated workpiece to produce an elongated product, said method comprising:
21. Method as in claim 20, wherein:
22. Method as in claim 21, wherein:
23. Method as in claim 20, wherein:
24. Method as in claim 23, wherein:
25. Method as in claim 20, wherein:
26. Method as in claim 25, wherein:
27. Method as in claim 25, wherein:
28. Method as in claim 20, further comprising:
29. Method for continuously deforming an elongated workpiece of indefinite length to produce an elongated product of indefinite length, said method comprising:
30. Method as in claim 29, wherein:
31. Method as in claim 29, wherein:
32. Method as in claim 31, wherein:
33. Method as in claim 31, wherein:
34. Method as in claim 29, further comprising:
35. Method as in claim 29, further comprising:
36. Apparatus for continuously deforming an elongated workpiece of indefinite length to produce an elongated product of indefinite length, said apparatus comprising:
37. Apparatus as in claim 36, wherein:
38. Apparatus as in claim 36, wherein:
39. Apparatus as in claim 36, wherein:
40. Apparatus for continuously deforming an elongated workpiece of indefinite length to produce an elongated product of indefinite length, said apparatus comprising:
41. Apparatus as in claim 40, wherein:
42. Apparatus as in claim 40, further comprising:
43. Apparatus as in claim 41, further comprising:
44. Apparatus for continuously deforming an elongated workpiece to produce an elongated product, said apparatus comprising:
45. Apparatus as in claim 44, wherein:
46. Apparatus as in claim 44, wherein:
47. Apparatus as in claim 44, wherein:
48. Apparatus as in claim 47, wherein:
49. Apparatus as in claim 44, wherein:
50. Apparatus as in claim 49, wherein:
51. Apparatus as in claim 49, wherein:
52. Apparatus as in claim 44, further comprising:
53. Apparatus for continuously deforming an elongated workpiece to produce an elongated product, said apparatus comprising:
54. Apparatus as in claim 53, wherein:
55. Apparatus as in claim 54, wherein:
56. Apparatus as in claim 53, wherein:
57. Apparatus as in claim 56, wherein:
58. Apparatus as in claim 53, wherein:
59. Apparatus as in claim 58, wherein:
60. Apparatus as in claim 58, wherein:
61. Apparatus as in claim 53, further comprising:
62. Apparatus for continuously deforming an elongated workpiece of indefinite length to produce an elongated product of indefinite length, said apparatus comprising:
63. Apparatus as in claim 62, wherein:
64. Apparatus as in claim 62, wherein:
65. Apparatus as in claim 64, wherein:
66. Apparatus as in claim 64, wherein:
67. Apparatus as in claim 62, further comprising:
68. Apparatus as in claim 62, further comprising:
69. Apparatus as in claim 62, wherein:
70. Apparatus as in claim 62, wherein:
71. Apparatus as in claim 62, wherein:
72. Apparatus as in claim 67, wherein:
73. Apparatus as in claim 68, wherein:
74. Method for continuously deforming an elongated workpiece of indefinite length to produce an elongated product of indefinite length, said method comprising:
75. Method for continuously deforming an elongated workpiece of indefinite length to produce an elongated product of indefinite length, said method comprising:
76. Apparatus for continuously deforming an elongated workpiece of indefinite length to produce an elongated product of indefinite length, said apparatus comprising:
77. Apparatus as in claim 76, wherein:
78. Apparatus for continuously deforming an elongated workpiece of indefinite length to produce an elongated product of indefinite length, said apparatus comprising:
79. Apparatus as in claim 78, wherein:
80. Apparatus as in claim 78, wherein:
81. Apparatus as in claim 80, wherein:
82. Apparatus as in claim 80, wherein:
1. Method for continuously deforming an elongated workpiece of indefinite length to produce an elongated product of indefinite length, said method comprising:
2. Method as in claim 1, further comprising:
3. Method as in claim 1, further comprising:
4. Method as in claim 2, further comprising:
5. Method for continuously deforming an elongated workpiece of indefinite length to produce an elongated product of indefinite length, said method comprising:
6. Method as in claim 5, further comprising:
7. Method as in claim 5, further comprising:
8. Method as in claim 6, further comprising:
9. Method as in claim 5, further comprising:
10. Method as in claim 5, further comprising:
11. Method for continuously deforming an elongated workpiece to produce an elongated product, said method comprising:
12. Method as in claim 11, wherein:
13. Method as in claim 12, wherein:
14. Method as in claim 11, wherein:
15. Method as in claim 14, wherein:
16. Method as in claim 11, wherein:
17. Method as in claim 16, wherein:
18. Method as in claim 16, wherein:
19. Method as in claim 11, wherein:
20. Method for continuously deforming an elongated workpiece to produce an elongated product, said method comprising:
21. Method as in claim 20, wherein:
22. Method as in claim 21, wherein:
23. Method as in claim 20, wherein:
24. Method as in claim 23, wherein:
25. Method as in claim 20, wherein:
26. Method as in claim 25, wherein:
27. Method as in claim 25, wherein:
28. Method as in claim 20, further comprising:
29. Method for continuously deforming an elongated workpiece of indefinite length to produce an elongated product of indefinite length, said method comprising:
30. Method as in claim 29, wherein:
31. Method as in claim 29, wherein:
32. Method as in claim 31, wherein:
33. Method as in claim 31, wherein:
34. Method as in claim 29, further comprising:
35. Method as in claim 29, further comprising:
36. Apparatus for continuously deforming an elongated workpiece of indefinite length to produce an elongated product of indefinite length, said apparatus comprising:
37. Apparatus as in claim 36, wherein:
38. Apparatus as in claim 36, wherein:
39. Apparatus as in claim 36, wherein:
40. Apparatus for continuously deforming an elongated workpiece of indefinite length to produce an elongated product of indefinite length, said apparatus comprising:
41. Apparatus as in claim 40, wherein:
42. Apparatus as in claim 40, further comprising:
43. Apparatus as in claim 41, further comprising:
44. Apparatus for continuously deforming an elongated workpiece to produce an elongated product, said apparatus comprising:
45. Apparatus as in claim 44, wherein:
46. Apparatus as in claim 44, wherein:
47. Apparatus as in claim 44, wherein:
48. Apparatus as in claim 47, wherein:
49. Apparatus as in claim 44, wherein:
50. Apparatus as in claim 49, wherein:
51. Apparatus as in claim 49, wherein:
52. Apparatus as in claim 44, further comprising:
53. Apparatus for continuously deforming an elongated workpiece to produce an elongated product, said apparatus comprising:
54. Apparatus as in claim 53, wherein:
55. Apparatus as in claim 54, wherein:
56. Apparatus as in claim 53, wherein:
57. Apparatus as in claim 56, wherein:
58. Apparatus as in claim 53, wherein:
59. Apparatus as in claim 58, wherein:
60. Apparatus as in claim 58, wherein:
61. Apparatus as in claim 53, further comprising:
62. Apparatus for continuously deforming an elongated workpiece of indefinite length to produce an elongated product of indefinite length, said apparatus comprising:
63. Apparatus as in claim 62, wherein:
64. Apparatus as in claim 62, wherein:
65. Apparatus as in claim 64, wherein:
66. Apparatus as in claim 64, wherein:
67. Apparatus as in claim 62, further comprising:
68. Apparatus as in claim 62, further comprising:
69. Apparatus as in claim 62, wherein:
70. Apparatus as in claim 62, wherein:
71. Apparatus as in claim 62, wherein:
72. Apparatus as in claim 67, wherein:
73. Apparatus as in claim 68, wherein:
74. Method for continuously deforming an elongated workpiece of indefinite length to produce an elongated product of indefinite length, said method comprising:
75. Method for continuously deforming an elongated workpiece of indefinite length to produce an elongated product of indefinite length, said method comprising:
76. Apparatus for continuously deforming an elongated workpiece of indefinite length to produce an elongated product of indefinite length, said apparatus comprising:
77. Apparatus as in claim 76, wherein:
78. Apparatus for continuously deforming an elongated workpiece of indefinite length to produce an elongated product of indefinite length, said apparatus comprising:
79. Apparatus as in claim 78, wherein:
80. Apparatus as in claim 78, wherein:
81. Apparatus as in claim 80, wherein:
82. Apparatus as in claim 80, wherein:
Description:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates, broadly speaking, to apparatus and method for continuous steady extrusion. More specifically, this invention relates to apparatus and method for continuously applying force along a portion of the surface of a rod of indefinite length to continuously advance the rod through an extrusion die.
2. Description of the Prior Art
Representative art showing the more-or-less continuous deformation of rod appears in the following patents and certificate: U. S. Pat. No. 2,642,280 (1953) to Fisk; U. S. Pat. No. 2,696,907 (1954) to Fisk; U. S. Pat. No. 2,736,425 (1956) to Fisk; U. S. Pat. No. 3,113,676 (1963) to Harkenrider; U. S. Pat. No. 3,415,088 (1968) to Alexander et al.; U. S. Pat. No. 3,417,589 (1968) to Bobrowsky; U. S. Pat. No. 3,423,983 (1969) to Lees et al.; U. S. Pat. No. 3,434,320 (1969) to Green; U. S. Pat. No. 3,440,849 (1969) to Hardy et al.; U. S. Pat. No. 3,449,935 (1969) to McAllan; U. S. Pat. No. 3,526,115 (1970) to Armstrong et al.; U.S.S.R. Author's Certificate 176,229 (1966) to Shvarzburd.
In my copending application Ser. No. 876,940, filed Nov. 14, 1969, and entitled "Apparatus and Method for Continuous Material Feeding and Deformation," there is shown apparatus and method for the continuous steady extrusion of rod of indefinite length, employing the viscous drag force of viscous fluid circuits, portions of which flow along the surface of the rod to build up stresses in the rod and advance the rod through an extrusion die. The disclosure of my copending application, Ser. No. 876,940, represents a milestone in the long history of the art of extrusion as theretofore known.
The present invention represents yet a further improvement in the art of extrusion.
SUMMARY OF THE INVENTION
One of the objects of this invention is to provide improved apparatus and method for the continuous deformation of an elongated workpiece of indefinite length.
Another of the objects of this invention is to provide improved apparatus and method for the continuous and steady extrusion of a rod of indefinite length to produce wire of indefinite length.
A further object of this invention is to provide improved apparatus and method for continuously applying force along a portion of the surface of a rod of indefinite length to build up stresses in the rod and to continuously and steadily advance the rod through an extrusion die.
Still other and further objects of this invention will become apparent during the course of the following description and by reference to the accompanying drawings and the appended claims.
Briefly, I have discovered that the foregoing objects may be attained by providing, in the preferred embodiment, four endless paths, each of said paths guiding a train or series of segments, each segment having gear teeth on the outer surface and having an inner configuration corresponding with the configuration of a quarter of the surface of the rod. Each train or series of segments is driven around its respective path by rotating spur gears, the said paths and their respective series of segments converging about the rod at a station upstream of an extrusion die and diverging at a station downstream of the extrusion die. The segments converged about the rod and being driven from the upstream station toward the downstream station apply a motive force along the surface of a shear transmitting medium which has been applied to the surface of the rod upstream of the upstream station and which shear transmitting medium is interposed between the inner surfaces of the segments and the rod surface, which shear transmitting medium in turn exerts viscous drag force along the surface of the rod to propel the rod through the extrusion die.
BRIEF DESCRIPTION OF THE DRAWING
Referring now to the drawings, in which like numerals represent like parts in the several views:
FIG. 1 represents a longitudinal view in elevation of the apparatus of the present invention, partially broken away to show certain internal features of construction, the rod entering the apparatus at the right being shown in phantom and the wire exiting the machine at the left likewise being shown in phantom;
FIG. 2 represents a transverse view in elevation of the apparatus of the present invention, taken from the right of FIG. 1;
FIG. 3 represents a transverse section taken along the line 3--3 of FIG. 1;
FIG. 4 represents a section taken along the line 4--4 of FIG. 2 of a portion of that end of the apparatus through which the rod enters, the rod being shown in phantom;
FIG. 5 represents a longitudinal view, partially in medial section and partially diagrammatic, of the apparatus of the present invention, with all but the last pinions of the several power trains omitted for purposes of simplifying the figure;
FIG. 6 represents a section taken along the line 6--6 of FIG. 5, showing certain track details;
FIG. 7 represents a section taken along the line 7--7 of FIG. 5, showing certain track details;
FIG. 8 represents a transverse medial section, partially broken away, of the pressure cylinder, showing the relationship of the extrusion die to the gripping elements closed about the rod;
FIG. 9 represents a transverse section of the pressure cylinder taken along the line 9--9 of FIG. 8; and
FIG. 10 represents a perspective diagrammatic view of the paths of the four sets of gripping elements relative to the rod and die, and illustrates the broad principle of operation of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Extrusion apparatus 1, for the continuous and steady extrusion of rod 2 of indefinite (i.e., unrestricted) length to form wire 3 likewise of indefinite (i.e., unrestricted) length is seen, in a broad overview, as comprising four groups or trains of gripping element quadrants 4, the gripping element quadrants 4 of each group or train being driven by a pinion gear 5a, 5b, 5c and 5d and by a pinion gear 25a, 25b, 25c and 25d around an endless path 6 defined in part by straight lengths 7 of track and curved sections 8 of track. The paths of the four groups or trains of gripping element quadrants 4 converge about rod 2 at the entrance end 9 of the apparatus 1, four gripping element quadrants 4, one from each group or train, cooperating to form a gripping element 10 encircling a portion of the surface of rod 2 (e.g., a length of rod 2 corresponding to the length of gripping element 10) whereby to move, in a manner to be described hereinafter, rod 2 through pressure cylinder 11 and extrusion die 12, the wire 3 resulting from the extrusion operation appearing at exit end 13 of apparatus 1, and the cooperating gripping element quadrants 4 diverging past (i.e., downstream of) extrusion die 12 and proceeding thence along their respective separate paths 6. It will be seen, further, that gripping elements 10 in series between the entrance end 9 and exit end 13 in effect constitute an endless pressure chamber about the length of rod 2 in the apparatus 1.
Having given this broad overview, the apparatus 1 will now be described in greater detail.
Gear blocks 14 and 15 are provided with central bores 16 and 17, respectively, and are counterbored slightly in their facing sides to receive the ends of pressure cylinder 11 having a central bore 18. Gear blocks 14 and 15 and pressure cylinder 11 are securely held in assembled relation, with the longitudinal axes of bores 16, 17 and 18 aligned by means of tie rods 19 extending completely through the said gear blocks 14 and 15 and tensioned by means of nuts 20 threaded on the ends of the said tie rods 19 sufficiently to bear on the far sides of gear blocks 14 and 15, as shown in FIG. 1.
Mounted to gear block 14, around that portion of gear block 14 adjacent the entrance end 9 of apparatus 1, are four fluid motors 21a, 21b, 21c and 21d preferably driven in unison from a common supply of pressurized motive fluid (not shown). Fluid motors 21a, 21b, 21c and 21d are arranged about the four faces of gear block 14 so as to occupy positions 90° removed from each other, when the apparatus 1 is viewed from an end thereof. Each fluid motor 21a, 21b, 21c and 21d drives a gear train 22a, 22b, 22c and 22d, respectively, suitably mounted and arranged within gear block 14 as shown in FIG. 3, and each gear train 22a, 22b, 22c and 22d drives a pinion gear 5a, 5b, 5c and 5d, the teeth of which extend into central bore 16 at positions 90° removed from each other as shown in FIG. 3. Mounted to gear block 14, around that portion of gear block 14 adjacent pressure cylinder 11, are four fluid motors 23a, 23b, 23c and 23d, preferably driven in unison from a common supply of pressurized fluid (not shown). Fluid motors 23a, 23b, 23c and 23d are arranged about the four faces of gear block 14 so as to occupy positions 90° removed from each other, when the apparatus 1 is viewed from an end thereof. Each fluid motor 23a, 23b, 23c and 23d drives a gear train 24a, 24b, 24c and 24d, respectively, suitably mounted and arranged within gear block 14, in a manner similar to the mounting and arrangement of gear trains 22a, 22b, 22c and 22d shown in FIG. 3. Each gear train 24a, 24b, 24c and 24d drives a pinion gear 25a, 25b, 24c and 25d, the teeth of which extend into central bore 16 at positions 90° removed from each other.
Mounted to gear block 15 are four fluid pumps 26a, 26b, 26c and 26d. Fluid pumps 26a, 26b, 26c and 26d are arranged about the four faces of gear block 15 so as to occupy positions 90° removed from each other, when the apparatus 1 is viewed from an end thereof. Each fluid pump 26a, 26b, 26c and 26d is driven by a gear train (not shown) suitably mounted and arranged within gear block 15 in a manner similar to the mounting and arrangement of gear trains 22a, 22b, 22c and 22d shown in FIG. 3, each said gear train being driven by a pinion gear 27a, 27b, 27c and 27d, the teeth of which extend into central bore 17 at positions 90° removed from each other.
It is the function of pinion gears 5a, 5b, 5c and 5d, and of pinion gears 25a, 25b, 25c and 25d, engaging the teeth of and driving gripping element quadrants 4 in the groups or trains thereof upstream from pressure cylinder 11, when operated, preferably in unison, by supplying their respective fluid motors 21a, 21b, 21c and 21d, and their respective fluid motors 23a, 23b, 23c and 23d with pressurized fluid from the source (not shown), to advance the said trains of gripping element quadrants 4 through the pressure cylinder 11 from the inlet or upstream end thereof toward the exit or downstream end thereof and thence around the several endless paths 6.
It is the function of pinion gears 27a, 27b, 27c and 27d, engaging and being driven by the teeth of advancing gripping element quadrants 4 in the groups or trains thereof downstream from pressure cylinder 11, to act as brakes on the said moving trains of gripping element quadrants, working against pinions 5a, 5b, 5c and 5d, and against pinions 25a, 25b, 25c and 25d, and thereby hold together, in rigid juxtaposition within pressure cylinder 11 between the inlet and exit ends thereof, all gripping element quadrants 4 in the same group or train.
Conveniently, the intakes of fluid pumps 26a, 26b, 26c and 26d may be connected by conduits (not shown) to the respective discharge ports of fluid motors 23a, 23b, 23c and 23d, and the discharge ports of fluid pumps 26a, 26b, 26c and 26d may be connected by suitable conduits (not shown) to the source of pressurized fluid serving fluid motors 21a, 21b, 21c, 21d, 23a, 23b, 23c and 23d. In this manner, the work of operating fluid pumps 26a, 26b, 26c and 26d to pump fluid therethrough will effect the desired braking action on the gripping element quadrants 4 within pressure cylinder 11.
It will be seen that four curved sections 8 of track are arranged at positions 90° removed from each other, when the apparatus is viewed transversely, at the exit end of central bore 17 of gear block 15, and that four curved sections 8 of track are arranged at positions 90° removed from each other, when the apparatus is viewed transversely at the inlet end of central bore 16 of gear block 14, and that the ends of said curved sections 8 of track at opposite ends of apparatus 1 are joined by straight sections 7 of track. Tracks 7, as shown in cross-section, particularly in FIGS. 6 and 7, comprise body portion 29 with quadrant-shaped longitudinal opening 30 receiving gripping element quadrants 4, retainer portion 31 having curved inner face 32 corresponding with the curved toothed exterior surface of gripping element quadrants 4, and threaded bolts 33 holding retainer portion 31 in place in body portion 29. Tracks 8 are of generally similar construction, receiving gripping element quadrants 4 and providing for a smooth transition in the paths 6 between straight sections 7 of track and central bores 16 and 17 of gear blocks 14 and 15.
Advantageously, gripping element quadrants 4 from the separate endless paths 6, which have met in that length of travel common to the said four endless paths 6 and therein constitute gripping elements 10, are maintained in closely abutting relation prior to and as they are engaged by pinions 5a, 5b, 5c and 5d, whereby to insure that they are properly engaged by the teeth of said pinions 5a, 5b, 5c and 5d and pass through pressure cylinder 11 without gaps therebetween. To compensate for the curved track sections 8 which, due to the configuration of gripping element quadrants 4, may cause gaps between adjacent gripping element quadrants 4 in certain portions of their respective endless paths 6, means are provided in each endless path 6 to urge the gripping element quadrants 4 in closely abutting relation, toward pinions 5a, 5b, 5c and 5d. Such means may, for example, comprise a transverse passage 29a in track 7 of each endless path 6, for the introduction of pressurized air between adjacent gripping element quadrants 4, thereby urging the gripping element quadrants 4, as they pass downstream of the conduit 29a against the train of gripping element quadrants 4 leading to pinions 5a, 5b, 5c and 5d.
Mounted within central bore 18 of pressure cylinder 11 is a sleeve 34 (FIG. 8) having an outer diameter such as to permit sleeve 34 to fit snugly within the said central bore 18. Sleeve 34 is somewhat longer than pressure cylinder 11 and projects from both ends thereof into the counterbores in the facing sides of gear blocks 14 and 15.
The outer surface of sleeve 34 is undercut or reduced in diameter at spaced lengths therealong, as shown in FIG. 8, thereby to provide spaced pairs of seal seats 35 receiving sealing rings 36 except at the ends of sleeve 34 where only single seal seats 35 with sealing rings 36 are provided, and further to provide between the spaced pairs of seal seats 35 (and between the endmost pairs of seal seats 35 and the single seal seats 35 adjacent thereto) annular compartments 37. The center-to-center distance between spaced pairs of seal seats 35 (and between the endmost pairs of seal seats 35 and the single seal seats 35 adjacent thereto) is, in the preferred embodiment, equal to the length of a gripping element quadrant 4.
Four sleeve quadrants 38a, 38b, 38c and 38d, each occupying 90° of arc, are positioned within sleeve 34 and collectively constitute a second sleeve 39 of outer diameter substantially equal to the inner diameter of sleeve 34 (i.e., the second sleeve 39 closely fits within sleeve 34) and of length equal to the length of sleeve 34. The sides of sleeve quadrants 38a, 38b, 38c and 38d are recessed so as to provide, when the sleeve quadrants 38a, 38b, 38c and 38d are assembled, a longitudinal circular recess 40 adapted to receive an elongated heating element (not shown), a seat 41 adapted to receive guide member 42, and a seat 43 adapted to receive a sealing plate 44. It will be noted, from FIG. 9, that guide members 42 extend inwardly of sleeve 39 and are 90° removed from each other. Gripping element quadrants 4 are each provided, on the outer portions of their mating faces, with a slot 45, and guide members 42, extending into the slots 45 between engaged gripping element quadrants 4, as shown in FIG. 9, function to key the gripping element 10 constituted by the said gripping element quadrants 4 to prevent the same from rotating in passing longitudinally through pressure cylinder 11.
It will be noted that, as each gripping element quadrant 4 passes along that portion of its path 6 defined by tracks 7 and 8, the cross-section of tracks 7 and 8 prevent the gripping element quadrant 4 from rotating transversely to its direction of movement. Means are provided to key the gripping element quadrants 4 as they leave curved tracks 8 and enter central bore 16 of gear block 14 at the entrance end 9 of the apparatus 1. Means are also provided to key the gripping element quadrants 4 as they leave central bore 17 of gear block 15 and enter curved tracks 8 at the exit end 13 of apparatus 1. Such means comprises guide members 46 arranged and secured in radially spaced relation to each other (i.e., at 90° angles to each other) inside central bores 16 and 17 of gear blocks 14 and 15, respectively. Corresponding guide members 46 in central bores 16 and 17 are aligned with each other and with corresponding guide members 42 in pressure cylinder 11, and are suitably oriented with respect to curved tracks 8 so that, as the gripping element quadrants 4 leave curved tracks 8 at the entrance end 9 of apparatus 1, guide members 46 in central bore 16 will register with slots 45 in adjacent gripping element quadrants 4; further, as gripping element quadrants 4 leave central bore 17 to enter curved tracks 8 at the exit end 13 of apparatus 1, slots 45 between adjacent gripping element quadrants 4 will clear guide members 46 and the individual gripping element quadrants 4 will enter their respective curved tracks 8 smoothly.
In the foregoing manner, gripping element quadrants 4 are guided around the entire length of their respective endless paths 6 (i.e., through track 7, track 8, central bore 16, pressure cylinder 11, central bore 17, track 8 and back to track 7).
Fluid passageways 47a, 47b, 47c and 47d are formed through the ends of sleeve quadrants 38a, 38b, 38c and 38d, respectively, midway between the sides thereof, and communicate with sources of pressurized fluid indicated diagrammatically by the numeral 48 through conduit 49. Fluid passageways 47a, 47b, 47c and 47d communicate, at their innermost ends with radial passageways 50a, 50b, 50c and 50d, respectively. The outer ends of radial passageways 50a, 50b, 50c and 50d communicate, through apertures 51 in sleeve 34, with endmost compartment 37, thereby to pressurize said endmost comparment 37 uniformly thereabout. This pressure is exerted, through sleeve 34 on sleeve quadrants 38a, 38b, 38c and 38d and thence on their respective gripping element quadrants 4, thereby forcing said gripping element quadrants inwardly and tightly about die 12 and die stem 12a.
The inner surfaces of sleeve quadrants 38a, 38b, 38c and 38d, opposite each of the pairs of sealing rings 36 and between guide members 42, are recessed at 52a, 52b, 52c and 52 d, to provide a fluid passageway between said inner surfaces and teeth 28 of gripping element quadrants 4. Elsewhere, there is a close sliding fit between the inner surfaces of sleeve quadrants 38a, 38b, 38c and 38d and teeth 28.
The inner ends of radial passageways 50a, 50b, 50c and 50d communicate with adjacent recesses 52a, 52b, 52c and 52d thereby to introduce pressurized fluid therein, adjacent the downstream (relative to the direction of movement of gripping element quadrants 4) sides of said adjacent recesses 52a, 52b, 52c and 52d. Thus, the pressurized fluid acting upon the external surfaces of gripping element quadrants 4, forces said gripping element quadrants 4 inwardly and tightly about rod 2 immediately upstream of die 12.
Adjacent the upstream (relative to the direction of movement of gripping element quadrants 4) sides of said last mentioned recesses 52a, 52b, 52c and 52d are provided pressure reducing valves 53a, 53b, 53c and 53d, communicating between said last mentioned recesses 52a, 52b, 52c and 52d and the next compartment 37. Pressure reducing valves 53a, 53b, 53c and 53d are adapted to vent pressurized fluid from said last mentioned recesses 52a, 52b, 52c and 52d, when the pressure of the fluid therein rises above a predetermined value, to said next compartment 37 at a lower pressure and thereby maintain a predetermined difference in pressure between the higher-pressurized last mentioned recesses 52a, 52b, 52c and 52d and the lower-pressurized next compartment 37.
Radial passageways 54a, 54b, 54c and 54d communicate between the upstream side of the last mentioned compartment 37 and the downstream sides of the next recesses 52a, 52b, 52c and 52d, thereby introducing pressurized fluid from said compartment 37 to said recesses 52a, 52b, 52c and 52d. Because of pressure reducing valves 53a, 53b, 53c and 53d, the pressure in said recesses 52a, 52b, 52c and 52d against the exterior surfaces of gripping element quadrants 4 is less than the pressure against the exterior surfaces of those gripping element quadrants 4 immediately downstream.
Pressure reducing valves 55a, 55b, 55c and 55d communicate between the upstream sides of said last-mentioned recesses 52a, 52b, 52c and 52d and the next compartment 37, and are adapted to vent pressurized fluid from said recesses 52a, 52b, 52c and 52d, when the pressure of the fluid therein rises above a predetermined value, to said next compartment 37 at a lower pressure and thereby maintain a predetermined difference in pressure between the said higher-pressurized recesses 52a, 52b, 52c and 52d and the lower-pressurized next compartment 37. Pressure reducing valves 55a, 55b, 55c and 55d are operative to pass pressurized fluid therethrough at a lower pressure than pressure reducing valves 53a, 53b, 53c and 53d, and therefore the pressure against the exterior surfaces of gripping element quadrants 4 passing by the recesses 52a, 52b , 52c and 52d associated with the said pressure reducing valves 55a, 55b, 55c and 55d is less than against the exterior surfaces of those gripping element quadrants immediately downstream.
The same arrangement of radial passageways and pressure reducing valves is provided for all the compartments 37 and recesses 52a, 52b, 52c and 52d upstream of those just described (i.e., to the right of FIG. 8). The pressure reducing valves are operative to pass pressurized fluid therethrough at lower levels than the immediately downstream pressure reducing valves. In this manner, the exterior surfaces of gripping element quadrants 4 are subjected to a pressure gradient increasing in steps from the time the gripping element quadrants 4 enter the upstream end of pressure cylinder 11 (i.e., the right end thereof as viewed in FIG. 8) until at least the time the gripping element quadrants 4 pass over die 12.
Pressurized fluid from the upstream-endmost compartment 37 may be fed back to a suitable pump (not shown) for subsequent recycling to the sources 48 of pressurized fluid.
Die stem 12a extends downstream of gear block 15, past the point at which gripping element quadrants 4 enter their respective curved tracks 8 as they leave central bore 17, and extends through die stem support 56 into a counterbore in support plate 57. Die stem support 56, secured to support plate 57, has a tapered nose 58 permitting it to extend closely between the diverging curved tracks 8 (FIG. 5) and thereby give effective lateral support to die stem 12a. Bolts 59, extending through support plate 57 and spacers 60, are threaded into the downstream side of gear block 15. In this manner, die 12 is securely supported against the thrust of rod 2.
Apparatus 61 for sizing and coating rod 2 with a shear transmitting medium before the said rod 2 enters apparatus 1 is seen as comprising housing 62 secured by means of threaded bolts 63 to radially spaced brackets 64 which, in turn, are secured to the upstream side of gear block 14 by means of threaded bolts 65. The longitudinal axis of housing 62 registers with the longitudinal axes of central bores 16 and 17 and of pressure cylinder 11. Housing 62 is provided with a first bore 66, a second larger bore 67, a third yet larger bore 68, a threaded section 69 and a fourth yet larger bore 70. Scraper 71 is positioned at the downstream side of bore 67, adjacent bore 66, and is secured in position by means of retainer ring 72. A sizing die 73 is mounted within bore 68, and is secured in position by means of threaded retaining ring 74 screwed into threaded section 69. A cover plate 75 having a projecting central portion 76 extending partially into bore 70 is secured to the upstream side of housing 62 by means of threaded bolts 77. Cover plate 75 is provided with counterbore 78 in which is mounted scraper 79 secured in position by means of retainer ring 80. Ring seal 81 is provided around projecting central portion 76 of cover plate 75.
It will be seen, in FIG. 4, that there is a space in bore 70, between threaded retaining ring 74 and projecting central portion 76. This space constitutes a first coating chamber 82.
It will also be seen, in FIG. 4, that there is a space in bore 67, between scraper 71 and sizing die 73. this space constitutes a second coating chamber 83.
Feed conduit 84 communicates between a source (not shown) of shear transmitting medium and first coating chamber 82, thereby to supply said first coating chamber 82 with shear transmitting medium. Drain conduit 85 is provided to withdraw excess shear transmitting medium from first coating chamber 82, and, through a suitable conduit (not shown), the withdrawn shear transmitting medium may be recycled to the source.
Feed conduit 86 communicates between a source (not shown) of shear transmitting medium and second coating chamber 83, thereby to supply said second coating chamber 83 with shear transmitting medium. Drain conduit 87 is provided to withdraw excess shear transmitting medium from second coating chamber 83 and, through a suitable conduit (not shown), the withdrawn shear transmitting medium may be recycled to the source.
The shear transmitting medium which may be utilized in practicing the present invention will desirably have a high viscosity and shear strength, be capable of lubricating die 12, provide good wetting action on the rod 2, and have minimal viscosity variation with respect to pressure, temperature and shearing rate. Such a medium may otherwise be known as viscous fluid, and examples of such a suitable medium are beeswax and polyethylene wax.
It is known in the art that many metals and other materials increase in ductility, or have an increased capacity for deformation without fracture, when they are subjected to high pressure. This effect is known as the "Bridgman effect," and the principle is treated in "Large Plastic Flow and Fracture" by P. W. Bridgman, published by McGraw Hill (New York, 1952). The present invention is particularly adapted to subject rod 2 to such high pressures. For example, when rod 2 is of aluminum, apparatus 1 is designed so that pressure on rod 2 adjacent die 12 will be approximately 150,000 psi, and where rod 2 is of copper, apparatus 1 is designed so that pressure on the rod 2 adjacent die 12 will be approximately 250,000 psi. These pressures are far above the respective yield strengths of aluminum and copper, and will increase the ductility, or capacity for deformation without fracture, of these materials.
The operation of the present invention will now be described.
Rod 2 is fed from a source of supply (not shown) through apparatus 61. In passing through scraper 79, dirt and the like are removed from the surface of rod 2. In passing through first coating chamber 82, the surface of rod 2 is provided with a coating of shear transmitting medium which medium, beeswax in the preferred embodiment, is capable of lubricating a die. In passing through sizing die 73, the diameter of rod 2 is sized to a uniform value. In passing through second coating chamber 83, the surface of rod 2 is recoated with shear transmitting medium. In passing through scraper 71, shear transmitting medium in excess of the desired thickness of coating thereof on the surface of rod 2 is removed. Thereafter, coated rod 2 enters the entrance end 9 of apparatus 1.
Fluid motors 21a-21d and 23a-23d are operated, whereby gripping element quadrants 4 are propelled around their respective endless paths 6, each gripping element quadrant 4 cooperating with a gripping element quadrant 4 from each of the other trains thereof as they enter central bore 16 of gear block 14 until they leave central bore 17 of gear block 15 to form a gripping element 10. Thus, there is a constantly moving continuous train of gripping elements 10 being propelled from the entrance end 9 to the exit end 13 of apparatus 1.
As coated rod 2 enters the entrance end 9 of apparatus 1 (i.e., the upstream end of central bore 16), a gripping element 10 closely contacts the entire perimetric surface of a length of shear transmitting medium coating on the surface of rod 2, which length corresponds to the length of the said gripping element 10. In being propelled toward the exit end 13 of apparatus 1, the gripping element 10 provides a motive force along the surface of the shear transmitting medium and thereby produces a shear force in the shear transmitting medium, which shear force is applied along the said perimetric surface of rod 2 as a friction or viscous drag force, directed toward the exit end 13 of apparatus 1, which friction or viscous drag force tends to propel rod 2 toward the said exit end. The cumulative effect of the several gripping elements 10 producing such friction or viscous drag force along the perimetric surface of rod 2 results in a longitudinal or axial compressive stress gradient in the rod 2, which gradient increases from the entrance end 9 toward the die 12. At the same time, inasmuch as there is no passageway along the exterior surface of die 12 for the flow of shear transmitting medium (i.e., all of the coating of viscous shear transmitting medium on the surface of rod 2 must pass through die 12 along with rod 2), the pressure in the coating of shear transmitting medium upstream of die 12 accumulates from the entrance end 9 toward the die 12. In other words a pressure gradient is established in the coating of shear transmitting medium which gradient increases from the entrance end 9 toward die 12. It will be apparent, to those familiar with this art, that normal stress in rod 2 is a function of the pressure in the shear transmitting medium, and therefore rod 2 experiences normal stress increasing from said entrance end 9 to said die 12. Apparatus 1 is designed to operate in such a manner that the difference between axial stress and normal stress in rod 2 upstream of die 12 does not exceed the yield strength of the rod material.
Gripping element quadrants 4 constituting gripping elements 10 are supported against, and thereby contain, the pressure in the shear transmitting medium coating on rod 2. From the entrance end 9 of apparatus 1 downstream to the downstream side of gear block 14, lateral support required to be given to the gripping element quadrants 4 is nominal, and this is provided by the wall of central bore 16, gripping element quadrants 4 being able to be moved readily through said central bore 16. Downstream of gear block 14, the pressure in the shear transmitting medium has risen to the point that substantial lateral support to gripping element quadrants 4 is required, which lateral support requirements will increase in the direction of die 12. It is the function of pressure cylinder 11 to supply this increasing lateral support to the gripping element quadrants in the manner hereinbefore described. It will be noted that the lateral support pressures obtained in pressure cylinder 11 are designed to balance the outward thrust on gripping element quadrants 4 developed by the increasing pressures in the shear transmitting medium and are related to the axial stresses developed in rod 2 in such a manner that (1) sufficient lateral support is given to gripping element quadrants 4 so that at all points along pressure cylinder 11, the normal stress in rod 2 never falls to such a value that the rod axial stress exceeds the rod normal stress by an amount exceeding the yield strength of the rod material (as otherwise the rod 2 would be caused to bulge out or mushroom) and (2) excessive support pressures on gripping element quadrants 4, particularly in the upstream section of pressure cylinder 4 are never produced (as otherwise this may crush gripping element quadrants 4 against rod 2).
In the preferred mode of operation, rod 2 as it advances within pressure cylinder 11 toward die 12 is stressed in compression far above its yield strength to the range at which it exhibits increased ductility, or has an increased capacity for deformation without fracture. In such a state, rod 2 passes into die 12, along with the coating of shear transmitting medium, and is deformed to produce wire 3.
From the foregoing description, it will be clear that I have invented novel apparatus and method for continuously deforming a workpiece (e.g., rod) of indefinite length to produce a product (e.g., wire) of indefinite length.
1. Field of the Invention
This invention relates, broadly speaking, to apparatus and method for continuous steady extrusion. More specifically, this invention relates to apparatus and method for continuously applying force along a portion of the surface of a rod of indefinite length to continuously advance the rod through an extrusion die.
2. Description of the Prior Art
Representative art showing the more-or-less continuous deformation of rod appears in the following patents and certificate: U. S. Pat. No. 2,642,280 (1953) to Fisk; U. S. Pat. No. 2,696,907 (1954) to Fisk; U. S. Pat. No. 2,736,425 (1956) to Fisk; U. S. Pat. No. 3,113,676 (1963) to Harkenrider; U. S. Pat. No. 3,415,088 (1968) to Alexander et al.; U. S. Pat. No. 3,417,589 (1968) to Bobrowsky; U. S. Pat. No. 3,423,983 (1969) to Lees et al.; U. S. Pat. No. 3,434,320 (1969) to Green; U. S. Pat. No. 3,440,849 (1969) to Hardy et al.; U. S. Pat. No. 3,449,935 (1969) to McAllan; U. S. Pat. No. 3,526,115 (1970) to Armstrong et al.; U.S.S.R. Author's Certificate 176,229 (1966) to Shvarzburd.
In my copending application Ser. No. 876,940, filed Nov. 14, 1969, and entitled "Apparatus and Method for Continuous Material Feeding and Deformation," there is shown apparatus and method for the continuous steady extrusion of rod of indefinite length, employing the viscous drag force of viscous fluid circuits, portions of which flow along the surface of the rod to build up stresses in the rod and advance the rod through an extrusion die. The disclosure of my copending application, Ser. No. 876,940, represents a milestone in the long history of the art of extrusion as theretofore known.
The present invention represents yet a further improvement in the art of extrusion.
SUMMARY OF THE INVENTION
One of the objects of this invention is to provide improved apparatus and method for the continuous deformation of an elongated workpiece of indefinite length.
Another of the objects of this invention is to provide improved apparatus and method for the continuous and steady extrusion of a rod of indefinite length to produce wire of indefinite length.
A further object of this invention is to provide improved apparatus and method for continuously applying force along a portion of the surface of a rod of indefinite length to build up stresses in the rod and to continuously and steadily advance the rod through an extrusion die.
Still other and further objects of this invention will become apparent during the course of the following description and by reference to the accompanying drawings and the appended claims.
Briefly, I have discovered that the foregoing objects may be attained by providing, in the preferred embodiment, four endless paths, each of said paths guiding a train or series of segments, each segment having gear teeth on the outer surface and having an inner configuration corresponding with the configuration of a quarter of the surface of the rod. Each train or series of segments is driven around its respective path by rotating spur gears, the said paths and their respective series of segments converging about the rod at a station upstream of an extrusion die and diverging at a station downstream of the extrusion die. The segments converged about the rod and being driven from the upstream station toward the downstream station apply a motive force along the surface of a shear transmitting medium which has been applied to the surface of the rod upstream of the upstream station and which shear transmitting medium is interposed between the inner surfaces of the segments and the rod surface, which shear transmitting medium in turn exerts viscous drag force along the surface of the rod to propel the rod through the extrusion die.
BRIEF DESCRIPTION OF THE DRAWING
Referring now to the drawings, in which like numerals represent like parts in the several views:
FIG. 1 represents a longitudinal view in elevation of the apparatus of the present invention, partially broken away to show certain internal features of construction, the rod entering the apparatus at the right being shown in phantom and the wire exiting the machine at the left likewise being shown in phantom;
FIG. 2 represents a transverse view in elevation of the apparatus of the present invention, taken from the right of FIG. 1;
FIG. 3 represents a transverse section taken along the line 3--3 of FIG. 1;
FIG. 4 represents a section taken along the line 4--4 of FIG. 2 of a portion of that end of the apparatus through which the rod enters, the rod being shown in phantom;
FIG. 5 represents a longitudinal view, partially in medial section and partially diagrammatic, of the apparatus of the present invention, with all but the last pinions of the several power trains omitted for purposes of simplifying the figure;
FIG. 6 represents a section taken along the line 6--6 of FIG. 5, showing certain track details;
FIG. 7 represents a section taken along the line 7--7 of FIG. 5, showing certain track details;
FIG. 8 represents a transverse medial section, partially broken away, of the pressure cylinder, showing the relationship of the extrusion die to the gripping elements closed about the rod;
FIG. 9 represents a transverse section of the pressure cylinder taken along the line 9--9 of FIG. 8; and
FIG. 10 represents a perspective diagrammatic view of the paths of the four sets of gripping elements relative to the rod and die, and illustrates the broad principle of operation of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Extrusion apparatus 1, for the continuous and steady extrusion of rod 2 of indefinite (i.e., unrestricted) length to form wire 3 likewise of indefinite (i.e., unrestricted) length is seen, in a broad overview, as comprising four groups or trains of gripping element quadrants 4, the gripping element quadrants 4 of each group or train being driven by a pinion gear 5a, 5b, 5c and 5d and by a pinion gear 25a, 25b, 25c and 25d around an endless path 6 defined in part by straight lengths 7 of track and curved sections 8 of track. The paths of the four groups or trains of gripping element quadrants 4 converge about rod 2 at the entrance end 9 of the apparatus 1, four gripping element quadrants 4, one from each group or train, cooperating to form a gripping element 10 encircling a portion of the surface of rod 2 (e.g., a length of rod 2 corresponding to the length of gripping element 10) whereby to move, in a manner to be described hereinafter, rod 2 through pressure cylinder 11 and extrusion die 12, the wire 3 resulting from the extrusion operation appearing at exit end 13 of apparatus 1, and the cooperating gripping element quadrants 4 diverging past (i.e., downstream of) extrusion die 12 and proceeding thence along their respective separate paths 6. It will be seen, further, that gripping elements 10 in series between the entrance end 9 and exit end 13 in effect constitute an endless pressure chamber about the length of rod 2 in the apparatus 1.
Having given this broad overview, the apparatus 1 will now be described in greater detail.
Gear blocks 14 and 15 are provided with central bores 16 and 17, respectively, and are counterbored slightly in their facing sides to receive the ends of pressure cylinder 11 having a central bore 18. Gear blocks 14 and 15 and pressure cylinder 11 are securely held in assembled relation, with the longitudinal axes of bores 16, 17 and 18 aligned by means of tie rods 19 extending completely through the said gear blocks 14 and 15 and tensioned by means of nuts 20 threaded on the ends of the said tie rods 19 sufficiently to bear on the far sides of gear blocks 14 and 15, as shown in FIG. 1.
Mounted to gear block 14, around that portion of gear block 14 adjacent the entrance end 9 of apparatus 1, are four fluid motors 21a, 21b, 21c and 21d preferably driven in unison from a common supply of pressurized motive fluid (not shown). Fluid motors 21a, 21b, 21c and 21d are arranged about the four faces of gear block 14 so as to occupy positions 90° removed from each other, when the apparatus 1 is viewed from an end thereof. Each fluid motor 21a, 21b, 21c and 21d drives a gear train 22a, 22b, 22c and 22d, respectively, suitably mounted and arranged within gear block 14 as shown in FIG. 3, and each gear train 22a, 22b, 22c and 22d drives a pinion gear 5a, 5b, 5c and 5d, the teeth of which extend into central bore 16 at positions 90° removed from each other as shown in FIG. 3. Mounted to gear block 14, around that portion of gear block 14 adjacent pressure cylinder 11, are four fluid motors 23a, 23b, 23c and 23d, preferably driven in unison from a common supply of pressurized fluid (not shown). Fluid motors 23a, 23b, 23c and 23d are arranged about the four faces of gear block 14 so as to occupy positions 90° removed from each other, when the apparatus 1 is viewed from an end thereof. Each fluid motor 23a, 23b, 23c and 23d drives a gear train 24a, 24b, 24c and 24d, respectively, suitably mounted and arranged within gear block 14, in a manner similar to the mounting and arrangement of gear trains 22a, 22b, 22c and 22d shown in FIG. 3. Each gear train 24a, 24b, 24c and 24d drives a pinion gear 25a, 25b, 24c and 25d, the teeth of which extend into central bore 16 at positions 90° removed from each other.
Mounted to gear block 15 are four fluid pumps 26a, 26b, 26c and 26d. Fluid pumps 26a, 26b, 26c and 26d are arranged about the four faces of gear block 15 so as to occupy positions 90° removed from each other, when the apparatus 1 is viewed from an end thereof. Each fluid pump 26a, 26b, 26c and 26d is driven by a gear train (not shown) suitably mounted and arranged within gear block 15 in a manner similar to the mounting and arrangement of gear trains 22a, 22b, 22c and 22d shown in FIG. 3, each said gear train being driven by a pinion gear 27a, 27b, 27c and 27d, the teeth of which extend into central bore 17 at positions 90° removed from each other.
It is the function of pinion gears 5a, 5b, 5c and 5d, and of pinion gears 25a, 25b, 25c and 25d, engaging the teeth of and driving gripping element quadrants 4 in the groups or trains thereof upstream from pressure cylinder 11, when operated, preferably in unison, by supplying their respective fluid motors 21a, 21b, 21c and 21d, and their respective fluid motors 23a, 23b, 23c and 23d with pressurized fluid from the source (not shown), to advance the said trains of gripping element quadrants 4 through the pressure cylinder 11 from the inlet or upstream end thereof toward the exit or downstream end thereof and thence around the several endless paths 6.
It is the function of pinion gears 27a, 27b, 27c and 27d, engaging and being driven by the teeth of advancing gripping element quadrants 4 in the groups or trains thereof downstream from pressure cylinder 11, to act as brakes on the said moving trains of gripping element quadrants, working against pinions 5a, 5b, 5c and 5d, and against pinions 25a, 25b, 25c and 25d, and thereby hold together, in rigid juxtaposition within pressure cylinder 11 between the inlet and exit ends thereof, all gripping element quadrants 4 in the same group or train.
Conveniently, the intakes of fluid pumps 26a, 26b, 26c and 26d may be connected by conduits (not shown) to the respective discharge ports of fluid motors 23a, 23b, 23c and 23d, and the discharge ports of fluid pumps 26a, 26b, 26c and 26d may be connected by suitable conduits (not shown) to the source of pressurized fluid serving fluid motors 21a, 21b, 21c, 21d, 23a, 23b, 23c and 23d. In this manner, the work of operating fluid pumps 26a, 26b, 26c and 26d to pump fluid therethrough will effect the desired braking action on the gripping element quadrants 4 within pressure cylinder 11.
It will be seen that four curved sections 8 of track are arranged at positions 90° removed from each other, when the apparatus is viewed transversely, at the exit end of central bore 17 of gear block 15, and that four curved sections 8 of track are arranged at positions 90° removed from each other, when the apparatus is viewed transversely at the inlet end of central bore 16 of gear block 14, and that the ends of said curved sections 8 of track at opposite ends of apparatus 1 are joined by straight sections 7 of track. Tracks 7, as shown in cross-section, particularly in FIGS. 6 and 7, comprise body portion 29 with quadrant-shaped longitudinal opening 30 receiving gripping element quadrants 4, retainer portion 31 having curved inner face 32 corresponding with the curved toothed exterior surface of gripping element quadrants 4, and threaded bolts 33 holding retainer portion 31 in place in body portion 29. Tracks 8 are of generally similar construction, receiving gripping element quadrants 4 and providing for a smooth transition in the paths 6 between straight sections 7 of track and central bores 16 and 17 of gear blocks 14 and 15.
Advantageously, gripping element quadrants 4 from the separate endless paths 6, which have met in that length of travel common to the said four endless paths 6 and therein constitute gripping elements 10, are maintained in closely abutting relation prior to and as they are engaged by pinions 5a, 5b, 5c and 5d, whereby to insure that they are properly engaged by the teeth of said pinions 5a, 5b, 5c and 5d and pass through pressure cylinder 11 without gaps therebetween. To compensate for the curved track sections 8 which, due to the configuration of gripping element quadrants 4, may cause gaps between adjacent gripping element quadrants 4 in certain portions of their respective endless paths 6, means are provided in each endless path 6 to urge the gripping element quadrants 4 in closely abutting relation, toward pinions 5a, 5b, 5c and 5d. Such means may, for example, comprise a transverse passage 29a in track 7 of each endless path 6, for the introduction of pressurized air between adjacent gripping element quadrants 4, thereby urging the gripping element quadrants 4, as they pass downstream of the conduit 29a against the train of gripping element quadrants 4 leading to pinions 5a, 5b, 5c and 5d.
Mounted within central bore 18 of pressure cylinder 11 is a sleeve 34 (FIG. 8) having an outer diameter such as to permit sleeve 34 to fit snugly within the said central bore 18. Sleeve 34 is somewhat longer than pressure cylinder 11 and projects from both ends thereof into the counterbores in the facing sides of gear blocks 14 and 15.
The outer surface of sleeve 34 is undercut or reduced in diameter at spaced lengths therealong, as shown in FIG. 8, thereby to provide spaced pairs of seal seats 35 receiving sealing rings 36 except at the ends of sleeve 34 where only single seal seats 35 with sealing rings 36 are provided, and further to provide between the spaced pairs of seal seats 35 (and between the endmost pairs of seal seats 35 and the single seal seats 35 adjacent thereto) annular compartments 37. The center-to-center distance between spaced pairs of seal seats 35 (and between the endmost pairs of seal seats 35 and the single seal seats 35 adjacent thereto) is, in the preferred embodiment, equal to the length of a gripping element quadrant 4.
Four sleeve quadrants 38a, 38b, 38c and 38d, each occupying 90° of arc, are positioned within sleeve 34 and collectively constitute a second sleeve 39 of outer diameter substantially equal to the inner diameter of sleeve 34 (i.e., the second sleeve 39 closely fits within sleeve 34) and of length equal to the length of sleeve 34. The sides of sleeve quadrants 38a, 38b, 38c and 38d are recessed so as to provide, when the sleeve quadrants 38a, 38b, 38c and 38d are assembled, a longitudinal circular recess 40 adapted to receive an elongated heating element (not shown), a seat 41 adapted to receive guide member 42, and a seat 43 adapted to receive a sealing plate 44. It will be noted, from FIG. 9, that guide members 42 extend inwardly of sleeve 39 and are 90° removed from each other. Gripping element quadrants 4 are each provided, on the outer portions of their mating faces, with a slot 45, and guide members 42, extending into the slots 45 between engaged gripping element quadrants 4, as shown in FIG. 9, function to key the gripping element 10 constituted by the said gripping element quadrants 4 to prevent the same from rotating in passing longitudinally through pressure cylinder 11.
It will be noted that, as each gripping element quadrant 4 passes along that portion of its path 6 defined by tracks 7 and 8, the cross-section of tracks 7 and 8 prevent the gripping element quadrant 4 from rotating transversely to its direction of movement. Means are provided to key the gripping element quadrants 4 as they leave curved tracks 8 and enter central bore 16 of gear block 14 at the entrance end 9 of the apparatus 1. Means are also provided to key the gripping element quadrants 4 as they leave central bore 17 of gear block 15 and enter curved tracks 8 at the exit end 13 of apparatus 1. Such means comprises guide members 46 arranged and secured in radially spaced relation to each other (i.e., at 90° angles to each other) inside central bores 16 and 17 of gear blocks 14 and 15, respectively. Corresponding guide members 46 in central bores 16 and 17 are aligned with each other and with corresponding guide members 42 in pressure cylinder 11, and are suitably oriented with respect to curved tracks 8 so that, as the gripping element quadrants 4 leave curved tracks 8 at the entrance end 9 of apparatus 1, guide members 46 in central bore 16 will register with slots 45 in adjacent gripping element quadrants 4; further, as gripping element quadrants 4 leave central bore 17 to enter curved tracks 8 at the exit end 13 of apparatus 1, slots 45 between adjacent gripping element quadrants 4 will clear guide members 46 and the individual gripping element quadrants 4 will enter their respective curved tracks 8 smoothly.
In the foregoing manner, gripping element quadrants 4 are guided around the entire length of their respective endless paths 6 (i.e., through track 7, track 8, central bore 16, pressure cylinder 11, central bore 17, track 8 and back to track 7).
Fluid passageways 47a, 47b, 47c and 47d are formed through the ends of sleeve quadrants 38a, 38b, 38c and 38d, respectively, midway between the sides thereof, and communicate with sources of pressurized fluid indicated diagrammatically by the numeral 48 through conduit 49. Fluid passageways 47a, 47b, 47c and 47d communicate, at their innermost ends with radial passageways 50a, 50b, 50c and 50d, respectively. The outer ends of radial passageways 50a, 50b, 50c and 50d communicate, through apertures 51 in sleeve 34, with endmost compartment 37, thereby to pressurize said endmost comparment 37 uniformly thereabout. This pressure is exerted, through sleeve 34 on sleeve quadrants 38a, 38b, 38c and 38d and thence on their respective gripping element quadrants 4, thereby forcing said gripping element quadrants inwardly and tightly about die 12 and die stem 12a.
The inner surfaces of sleeve quadrants 38a, 38b, 38c and 38d, opposite each of the pairs of sealing rings 36 and between guide members 42, are recessed at 52a, 52b, 52c and 52 d, to provide a fluid passageway between said inner surfaces and teeth 28 of gripping element quadrants 4. Elsewhere, there is a close sliding fit between the inner surfaces of sleeve quadrants 38a, 38b, 38c and 38d and teeth 28.
The inner ends of radial passageways 50a, 50b, 50c and 50d communicate with adjacent recesses 52a, 52b, 52c and 52d thereby to introduce pressurized fluid therein, adjacent the downstream (relative to the direction of movement of gripping element quadrants 4) sides of said adjacent recesses 52a, 52b, 52c and 52d. Thus, the pressurized fluid acting upon the external surfaces of gripping element quadrants 4, forces said gripping element quadrants 4 inwardly and tightly about rod 2 immediately upstream of die 12.
Adjacent the upstream (relative to the direction of movement of gripping element quadrants 4) sides of said last mentioned recesses 52a, 52b, 52c and 52d are provided pressure reducing valves 53a, 53b, 53c and 53d, communicating between said last mentioned recesses 52a, 52b, 52c and 52d and the next compartment 37. Pressure reducing valves 53a, 53b, 53c and 53d are adapted to vent pressurized fluid from said last mentioned recesses 52a, 52b, 52c and 52d, when the pressure of the fluid therein rises above a predetermined value, to said next compartment 37 at a lower pressure and thereby maintain a predetermined difference in pressure between the higher-pressurized last mentioned recesses 52a, 52b, 52c and 52d and the lower-pressurized next compartment 37.
Radial passageways 54a, 54b, 54c and 54d communicate between the upstream side of the last mentioned compartment 37 and the downstream sides of the next recesses 52a, 52b, 52c and 52d, thereby introducing pressurized fluid from said compartment 37 to said recesses 52a, 52b, 52c and 52d. Because of pressure reducing valves 53a, 53b, 53c and 53d, the pressure in said recesses 52a, 52b, 52c and 52d against the exterior surfaces of gripping element quadrants 4 is less than the pressure against the exterior surfaces of those gripping element quadrants 4 immediately downstream.
Pressure reducing valves 55a, 55b, 55c and 55d communicate between the upstream sides of said last-mentioned recesses 52a, 52b, 52c and 52d and the next compartment 37, and are adapted to vent pressurized fluid from said recesses 52a, 52b, 52c and 52d, when the pressure of the fluid therein rises above a predetermined value, to said next compartment 37 at a lower pressure and thereby maintain a predetermined difference in pressure between the said higher-pressurized recesses 52a, 52b, 52c and 52d and the lower-pressurized next compartment 37. Pressure reducing valves 55a, 55b, 55c and 55d are operative to pass pressurized fluid therethrough at a lower pressure than pressure reducing valves 53a, 53b, 53c and 53d, and therefore the pressure against the exterior surfaces of gripping element quadrants 4 passing by the recesses 52a, 52b , 52c and 52d associated with the said pressure reducing valves 55a, 55b, 55c and 55d is less than against the exterior surfaces of those gripping element quadrants immediately downstream.
The same arrangement of radial passageways and pressure reducing valves is provided for all the compartments 37 and recesses 52a, 52b, 52c and 52d upstream of those just described (i.e., to the right of FIG. 8). The pressure reducing valves are operative to pass pressurized fluid therethrough at lower levels than the immediately downstream pressure reducing valves. In this manner, the exterior surfaces of gripping element quadrants 4 are subjected to a pressure gradient increasing in steps from the time the gripping element quadrants 4 enter the upstream end of pressure cylinder 11 (i.e., the right end thereof as viewed in FIG. 8) until at least the time the gripping element quadrants 4 pass over die 12.
Pressurized fluid from the upstream-endmost compartment 37 may be fed back to a suitable pump (not shown) for subsequent recycling to the sources 48 of pressurized fluid.
Die stem 12a extends downstream of gear block 15, past the point at which gripping element quadrants 4 enter their respective curved tracks 8 as they leave central bore 17, and extends through die stem support 56 into a counterbore in support plate 57. Die stem support 56, secured to support plate 57, has a tapered nose 58 permitting it to extend closely between the diverging curved tracks 8 (FIG. 5) and thereby give effective lateral support to die stem 12a. Bolts 59, extending through support plate 57 and spacers 60, are threaded into the downstream side of gear block 15. In this manner, die 12 is securely supported against the thrust of rod 2.
Apparatus 61 for sizing and coating rod 2 with a shear transmitting medium before the said rod 2 enters apparatus 1 is seen as comprising housing 62 secured by means of threaded bolts 63 to radially spaced brackets 64 which, in turn, are secured to the upstream side of gear block 14 by means of threaded bolts 65. The longitudinal axis of housing 62 registers with the longitudinal axes of central bores 16 and 17 and of pressure cylinder 11. Housing 62 is provided with a first bore 66, a second larger bore 67, a third yet larger bore 68, a threaded section 69 and a fourth yet larger bore 70. Scraper 71 is positioned at the downstream side of bore 67, adjacent bore 66, and is secured in position by means of retainer ring 72. A sizing die 73 is mounted within bore 68, and is secured in position by means of threaded retaining ring 74 screwed into threaded section 69. A cover plate 75 having a projecting central portion 76 extending partially into bore 70 is secured to the upstream side of housing 62 by means of threaded bolts 77. Cover plate 75 is provided with counterbore 78 in which is mounted scraper 79 secured in position by means of retainer ring 80. Ring seal 81 is provided around projecting central portion 76 of cover plate 75.
It will be seen, in FIG. 4, that there is a space in bore 70, between threaded retaining ring 74 and projecting central portion 76. This space constitutes a first coating chamber 82.
It will also be seen, in FIG. 4, that there is a space in bore 67, between scraper 71 and sizing die 73. this space constitutes a second coating chamber 83.
Feed conduit 84 communicates between a source (not shown) of shear transmitting medium and first coating chamber 82, thereby to supply said first coating chamber 82 with shear transmitting medium. Drain conduit 85 is provided to withdraw excess shear transmitting medium from first coating chamber 82, and, through a suitable conduit (not shown), the withdrawn shear transmitting medium may be recycled to the source.
Feed conduit 86 communicates between a source (not shown) of shear transmitting medium and second coating chamber 83, thereby to supply said second coating chamber 83 with shear transmitting medium. Drain conduit 87 is provided to withdraw excess shear transmitting medium from second coating chamber 83 and, through a suitable conduit (not shown), the withdrawn shear transmitting medium may be recycled to the source.
The shear transmitting medium which may be utilized in practicing the present invention will desirably have a high viscosity and shear strength, be capable of lubricating die 12, provide good wetting action on the rod 2, and have minimal viscosity variation with respect to pressure, temperature and shearing rate. Such a medium may otherwise be known as viscous fluid, and examples of such a suitable medium are beeswax and polyethylene wax.
It is known in the art that many metals and other materials increase in ductility, or have an increased capacity for deformation without fracture, when they are subjected to high pressure. This effect is known as the "Bridgman effect," and the principle is treated in "Large Plastic Flow and Fracture" by P. W. Bridgman, published by McGraw Hill (New York, 1952). The present invention is particularly adapted to subject rod 2 to such high pressures. For example, when rod 2 is of aluminum, apparatus 1 is designed so that pressure on rod 2 adjacent die 12 will be approximately 150,000 psi, and where rod 2 is of copper, apparatus 1 is designed so that pressure on the rod 2 adjacent die 12 will be approximately 250,000 psi. These pressures are far above the respective yield strengths of aluminum and copper, and will increase the ductility, or capacity for deformation without fracture, of these materials.
The operation of the present invention will now be described.
Rod 2 is fed from a source of supply (not shown) through apparatus 61. In passing through scraper 79, dirt and the like are removed from the surface of rod 2. In passing through first coating chamber 82, the surface of rod 2 is provided with a coating of shear transmitting medium which medium, beeswax in the preferred embodiment, is capable of lubricating a die. In passing through sizing die 73, the diameter of rod 2 is sized to a uniform value. In passing through second coating chamber 83, the surface of rod 2 is recoated with shear transmitting medium. In passing through scraper 71, shear transmitting medium in excess of the desired thickness of coating thereof on the surface of rod 2 is removed. Thereafter, coated rod 2 enters the entrance end 9 of apparatus 1.
Fluid motors 21a-21d and 23a-23d are operated, whereby gripping element quadrants 4 are propelled around their respective endless paths 6, each gripping element quadrant 4 cooperating with a gripping element quadrant 4 from each of the other trains thereof as they enter central bore 16 of gear block 14 until they leave central bore 17 of gear block 15 to form a gripping element 10. Thus, there is a constantly moving continuous train of gripping elements 10 being propelled from the entrance end 9 to the exit end 13 of apparatus 1.
As coated rod 2 enters the entrance end 9 of apparatus 1 (i.e., the upstream end of central bore 16), a gripping element 10 closely contacts the entire perimetric surface of a length of shear transmitting medium coating on the surface of rod 2, which length corresponds to the length of the said gripping element 10. In being propelled toward the exit end 13 of apparatus 1, the gripping element 10 provides a motive force along the surface of the shear transmitting medium and thereby produces a shear force in the shear transmitting medium, which shear force is applied along the said perimetric surface of rod 2 as a friction or viscous drag force, directed toward the exit end 13 of apparatus 1, which friction or viscous drag force tends to propel rod 2 toward the said exit end. The cumulative effect of the several gripping elements 10 producing such friction or viscous drag force along the perimetric surface of rod 2 results in a longitudinal or axial compressive stress gradient in the rod 2, which gradient increases from the entrance end 9 toward the die 12. At the same time, inasmuch as there is no passageway along the exterior surface of die 12 for the flow of shear transmitting medium (i.e., all of the coating of viscous shear transmitting medium on the surface of rod 2 must pass through die 12 along with rod 2), the pressure in the coating of shear transmitting medium upstream of die 12 accumulates from the entrance end 9 toward the die 12. In other words a pressure gradient is established in the coating of shear transmitting medium which gradient increases from the entrance end 9 toward die 12. It will be apparent, to those familiar with this art, that normal stress in rod 2 is a function of the pressure in the shear transmitting medium, and therefore rod 2 experiences normal stress increasing from said entrance end 9 to said die 12. Apparatus 1 is designed to operate in such a manner that the difference between axial stress and normal stress in rod 2 upstream of die 12 does not exceed the yield strength of the rod material.
Gripping element quadrants 4 constituting gripping elements 10 are supported against, and thereby contain, the pressure in the shear transmitting medium coating on rod 2. From the entrance end 9 of apparatus 1 downstream to the downstream side of gear block 14, lateral support required to be given to the gripping element quadrants 4 is nominal, and this is provided by the wall of central bore 16, gripping element quadrants 4 being able to be moved readily through said central bore 16. Downstream of gear block 14, the pressure in the shear transmitting medium has risen to the point that substantial lateral support to gripping element quadrants 4 is required, which lateral support requirements will increase in the direction of die 12. It is the function of pressure cylinder 11 to supply this increasing lateral support to the gripping element quadrants in the manner hereinbefore described. It will be noted that the lateral support pressures obtained in pressure cylinder 11 are designed to balance the outward thrust on gripping element quadrants 4 developed by the increasing pressures in the shear transmitting medium and are related to the axial stresses developed in rod 2 in such a manner that (1) sufficient lateral support is given to gripping element quadrants 4 so that at all points along pressure cylinder 11, the normal stress in rod 2 never falls to such a value that the rod axial stress exceeds the rod normal stress by an amount exceeding the yield strength of the rod material (as otherwise the rod 2 would be caused to bulge out or mushroom) and (2) excessive support pressures on gripping element quadrants 4, particularly in the upstream section of pressure cylinder 4 are never produced (as otherwise this may crush gripping element quadrants 4 against rod 2).
In the preferred mode of operation, rod 2 as it advances within pressure cylinder 11 toward die 12 is stressed in compression far above its yield strength to the range at which it exhibits increased ductility, or has an increased capacity for deformation without fracture. In such a state, rod 2 passes into die 12, along with the coating of shear transmitting medium, and is deformed to produce wire 3.
From the foregoing description, it will be clear that I have invented novel apparatus and method for continuously deforming a workpiece (e.g., rod) of indefinite length to produce a product (e.g., wire) of indefinite length.