Assignee:
The Steel Company of Canada, Limited (Hamilton, Ontario, CA)
Claims:
The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows
1. A spinning head useful in the production of helical wire comprising (a) a spinner head having sections of different radius of which the first section is dimensioned to contain a die and a second section is dimensioned to receive on its outer surface an axial thrust bearing, (b) a spinner housing adapted to fit into a standard die holder on a simple wire drawing frame and to receive within it the spinner head and having on its inner surface sections of differing radius which are a first section to receive said first section of said spinner head, a second section to receive said axial thrust bearing and a third section to receive said second section of said spinner head, (c) an axial thrust bearing positioned between said spinner head and said spinner housing on said second section of the spinner head and within said third section of said housing and abutting the wall formed between said first and second sections of said head and the wall formed between said second and third portions of said housing (d) means to retain said spinner head within said spinner housing and (e) means to permit the feeding of lubricant to the bearing, and wherein said spinner head projects from each end of the spinner housing.
2. A spinning head as claimed in claim 1 in which the projecting portion of the first section of the spinner head has formed in it threaded holes to receive screws to retain the die in position.
3. A spinning head as claimed in claim 1 in which the projecting portion of the second section of the spinner head has a channel formed in it that contains a circlip that comprises the means of retaining the spinner head within the spinner housing.
Description:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a spinning head useful in the production by cold drawing of (helical or spiral) wire.
2. Description of the Prior Art
Common or simple wire, that is wire of circular or similar simple cross section, is formed by cold drawing rod through a die made of a wear-resistant material, commonly tungsten carbide, that has a tapering hole called a die hole. Initially a point is formed on the rod and the point is pushed through the die and anchored to a wire drawing block that is rotatable. Wire is then formed by pulling the rod through the die. To dissipate the heat generated the die is located in die holder positioned in a water jacket through which water is circulated. The rod is lubricated by passing it through a lubricant immediately before it is pulled into the die. The lubricants facilitate passage of the rod through the die. Powdered soap is one commonly used lubricant. The soap is put in a soap box positioned so that the rod passes through the soap before it enters the die. The soap box is normally formed integrally with the die stand, which provides the means of locating the die, the cooling jacket and other necessary features to permit efficient operation of the die.
Wire may be drawn through the die in one passage, or in steps depending upon the total reduction of area required. If more than one passage is required this is carried out on a wire drawing frame upon which are mounted a number of dies each having a different die hole diameter. Each die is water cooled- possibly from a common water supply and exhaust system- and each die is provided with its own soap box. The rod is taken successively through die holes of decreasing diameter until a wire of the desired gauge is obtained. The finished wire is drawn unto the drawing block. When a block is full the wire is removed from the block and the operation is restarted.
The die stand with its soap box is adjustable in vertical and horizontal planes and provides a means of locating the die and of ensuring that the produced wire has good dead cast. The die stand achieves the function of location and dead cast control by having its base extend beyond the sides of the soap box to provide a flange. Bolts extend through threaded holes in the flange and the die is thus provided with fine levelling adjustments and with location means. By adjustment of the bolts it is easy for the skilled operator to ensure that the wire produced has good dead cast.
U.S. Pat. No. 2,928,528 describes a wire drawing die having a passage through it of gradually diminishing cross section throughout a substantial portion of its working length. The passage has a general cross-sectional shape that is non-circular over at least a substantial portion of its working length and is helically twisted about its longitudinal axis throughout the portion of non-circular cross-section. Such a die is used in an apparatus that permits the die to rotate during drawing and has proved to be a great success in producing helical wire or, more generally, wire characterized by crests and valleys in which grain flow lines run longitudinally. In the die of U.S. Pat. No. 2,928,528, and in developments of it, for example the die of U.S. Pat. No. 3,038,592, a radial ball bearing is used to permit the die and the die holder to rotate. The bearing is lubricated, usually by oil mist.
The dies of the above United States patents have proved valuable industrial tools but their use has certain inconveniences. The dies are used on wire drawing machinery designed for simple wire drawing in a non-rotating die. For example the rotating die is often used in place of the last die on a conventional wire drawing frame. That is, rod is reduced on conventional dies then given a helical configuration in the last die on the frame. However it is not economically sound to have a wire drawing frame restricted to the production of helical wire. It is desirable to be able to change the last die on a wire drawing frame to enable the frame to be used for the production of either simple wire or helical wire. On existing apparatus the changing of the dies can take up to one and one half hours and involve the services of a mill wright and a pipe fitter. To change from a simple die to a helical die requires the following steps:
i. The machine is stopped and the coolant flow is switched off.
ii. The coolant connections to the finishing die stand are broken.
iii. The locating bolts in the die stand and soap box of the simple die are removed- thus upsetting the dead cast adjustments- and the complete die stand unit, including its soap box, is removed from the wire drawing frame.
iv. In place of the simple die stand is inserted a fabricated frame carrying the helical die with its attendent cooling jackets, a radial ball bearing, flyer, or spinner head, retaining rings and lock nuts.
v. The level of the fabricated frame is adjusted to ensure that the wire produced has good dead cast and the coolant and lubricant connections are reconnected.
The machine is ready for use although in running the machine it may be found that it is necessary to adjust the level of the die holder to improve the dead cast of the produced wire.
Unless process maintenance is observed, the rotating die may be subject to seizure. Specially lapped bearings are necessary, and free rotation requires frequent servicing.
SUMMARY OF THE INVENTION
The present invention provides an improvement over the above wire drawing apparatus. In particular the present invention provides a spinning head that can be used in most existing, simple die holders. Furthermore the change of simple die to helical die takes about five minutes. Water connections are not broken during the change as the same die holder and cooling jacket is used for rotating or fixed dies. The means of locating the spinning heads in place is the same for each die. It follows that adjustment of the dead cast for the helical wire is not necessary. The adjustment that has been made for the production of simple wire is sufficient. A die in the spinning head of the present invention can be operated at higher speeds than on the prior art spinning head. The old spinning head is more expensive than the head of the present invention and, depending on the size, may be about five to eight times more expensive. In general the present invention provides a spinning head in which all the disadvantages of the prior art spinning heads are reduced and may be eliminated.
The invention is illustrated in the drawings in which
FIG. 1 is an exploded view of the spinning head according to the present invention,
FIG. 2 is a section through the spinning head of FIG. 1,
FIG. 3 is a partially exploded plan view of a die stand showing a spinning head according to the present invention, and
FIG. 4 illustrates a conventional, non-spinning die with holder.
The drawings show a spinning head comprising a spinner head 2 having sections of different radius. A first section 4 is dimensioned to receive a die (not shown). A second section 6 is dimensioned to receive on its outer surface an axial thrust bearing 8. The bearing 8 abuts the wall 10 between the sections 4 and 6. The first section 4 of the spinner head 2 is formed with threaded holes 12 that receives screws 14 to locate the die in position. The second section 6 of the spinner head 2 is formed with a channel 16 that receives a circlip 18.
The spinner head 2 is positioned within a spinner housing 20. The spinner housing 20 fits into a water cooled die holder on a wire drawing frame (not shown). The spinner housing has on its inside surface sections of different radius. A first section 22 receives the first section 4 of the spinner head 2. A second section 24 receives the bearing 8 and a third section 26 receives the second section 6 of the spinner head 2. The bearing 8 abuts the wall 28 between the second section 24 and the third section 26. A fourth section 30 in the spinner housing 20 receives a sealing ring 32. This sealing ring prevents dirt and soap from reaching the bearing 8. The spinner head 2 is retained in the spinner housing 20 by the circlip 18.
Lubricant is fed to the bearing 8 along the passageway 34. The passageway 34 is fitted with a connector 36 joined to a lubricant supply. The preferred lubricant is oil mist.
FIGS. 3 and 4 illustrate the ease of change over from a simple die to a spinning die when the spinning die is mounted in a spinning head according to the present invention. FIG. 3 shows a die stand 38 located by bolts 40 and 42 on a wire drawing frame (not shown). Bolts 40 and 42 are adjusted to control the dead cast of the wire produced. However as such adjustment is well known to the skilled man it is not proposed to describe the adjustments here. The frame 38 is formed with a soap box 44 and has, adjacent one of its ends, a cavity 46 to receive a die holder. The cavity 46 is surrounded by coolant jacket 48. Coolant is pumped into the jacket 48 through inlet pipe 50 and is pumped out of the jacket 48 through pipe 52. The jacket has positioned in it a threaded insert 54 into which a locking screw 56 is screwed. A further locking screw 58 is positioned in a similar vertical threaded insert (not shown). A die-holder 60 fits into the cavity 46. The die holder 60 is fitted with threaded holes 62 to receive locking screws 56 and 58. The spinning head according to the present invention, generally designated by the spinner housing 20, fits into the die holder 60. The spinner housing 20 is locked in the die holder 60 by the locking screws 56 and 58 abutting the outer surface of the spinner housing 20. A die 65 suitable for the production of wire of helical cross-section is locked into the spinner head 2 of the spinning head of the present invention.
The prior art illustrated in FIG. 4 shows the same die-holder 60 but containing a sleeve 64 provided with a cavity 66 to receive a conventional wire drawing die 68. The steel sleeve 64 is provided with threaded holes 70 to receive the locking screws 56 and 58.
It is clear from FIGS. 3 and 4 that the spinning head according to the present invention can be removed simply by disconnecting the lubricant supply connector 36 and by unscrewing locking screws 56 and 58. It is not even necessary to switch off the coolant supply to the cooling chamber 48. When the spinning die and the spinning head of the invention have been removed steel sleeve 64 containing die 68 is inserted into the die-holder 60 and locked into place with the screws 56 and 58.
The reverse change is equally simple. The locking screws 56 and 58 are loosened the steel sleeve 64 and the die 68 are removed and the spinning head 20 with die 62 are inserted into the die-holder 60. The oil supply is rejoined to connector 36 to permit feeding of lubricant to the bearing 8.
With a very large conventional die 68 the sleeve 64 may not be necessary. The die 68 may be sufficiently large to fit directly into the die holder 60.