Title:
TOP FEED MECHANISM FOR OVEREDGE SEWING MACHINE
United States Patent 3636899
Abstract:
This disclosure relates to a top feed mechanism for an overedge sewing machine in which a top feed dog is articulately mounted upon a top feed bar to which feed and lift motions are transmitted by eccentrics. The top feed dog is carried by a pivotally mounted arm which is in turn connected to a slidably mounted rod above and generally in the plane of the top feed bar. Biasing means normally urge the rod in a direction tending to move the feed dog toward its fabric engaging position. Cam means carried by a rotatable plate are provided for moving the rod against the biasing force of the spring to pivot the arm and the feed dog carried thereby to an out-of-the-way position. Lifting motion is imparted to the top feed bar and a main feed bar by eccentrics which are generally 180° out of phase whereby the feed dogs move toward each other to grip fabric therebetween during the feed cycle and move away from each other to release fabric incident to the return cycle of the mechanism.
US Patent References:
WORK FEEDER FOR SEWING MACHINE
Porter - September 1970 - 3530809
Feeding mechanism for sewing machines
Nering - March 1958 - 2827869
Feeding mechanism for sewing machines
Rubel et al. - March 1935 - 1995945
Sewing machines
Chezaud et al. - June 1966 - 3256844
WORK FEEDER FOR SEWING MACHINE
Porter - September 1970 - 3530809
Feeding mechanism for sewing machines
Nering - March 1958 - 2827869
Feeding mechanism for sewing machines
Rubel et al. - March 1935 - 1995945
Sewing machines
Chezaud et al. - June 1966 - 3256844
Application Number:
05/017088
Publication Date:
01/25/1972
Filing Date:
03/06/1970
View Patent Images:
Export Citation:
Assignee:
Union Special Machine Company (Chicago, IL)
Primary Class:
International Classes:
D05B27/04; D05B73/12; D05B27/00; D05B73/00; D05B27/06
Field of Search:
112/207,212,162,213
Primary Examiner:
Scanlan Jr., Richard J.
Claims:
I claim
1. A top feed mechanism for sewing machines comprising a top feed bar and a main feed bar, means articulately mounting a top feed dog upon said top feed bar, means mounting a main feed dog upon said main feed bar, first means for imparting lift and feed motions to said main feed bar, second means for imparting lift and feed motions to said top feed bar, lift imparting portions of said first and second means being directionally in phase whereby said feed dogs move toward and away from each other in substantial unison during respective feed and retract cycles of said feed bars, and common drive means for imparting motion to said lift imparting portions.
2. The top feed mechanism as defined in claim 1 including means for biasing said top feed dog toward its fabric engaging position.
3. The top feed mechanism as defined in claim 1 including means for biasing said top feed dog toward its fabric engaging position, and means for adjusting said biasing means to regulate the force applied to fabric by said top feed dog.
4. The top feed mechanism as defined in claim 1 including means for camming said top feed dog away from its fabric engaging position.
5. The top feed mechanism as defined in claim 1 including means for limiting the movement of said top feed dog between fabric engaging and fabric disengaging positions thereof.
6. The top feed mechanism as defined in claim 1 wherein said mounting means includes means for pivotal movement of said top feed dog relative to said feed bar.
7. The top feed mechanism as defined in claim 1 wherein said mounting means includes a pivotally mounted arm carrying said top feed dog for pivotal movement relative to said top feed bar, an actuator rod connected to said arm, and means for moving said rod to pivot said arm and the top feed dog carried thereby away from its fabric engaging position.
8. The top feed mechanism as defined in claim 7 including means carried by said top feed bar mounting said rod for sliding movement relative thereto.
9. A top feed mechanism comprising a top feed bar adapted to be mounted below the horizontal plane of an associated sewing machine throat plate, means for imparting lift and feed motions to said top feed bar, a feed dog, means articulately mounting said feed dog upon said top feed bar, said mounting means including a pivotally mounted arm carrying said feed dog for pivotal movement relative to said feed bar, an actuator rod connected to said arm, means for moving said rod to pivot said arm and the feed dog carried thereby away from its fabric engaging position, means carried by said feed bar mounting said rod for sliding movement relative thereto, and said rod moving means includes cam means for imparting sliding movement to said rod.
10. The top feed mechanism as defined in claim 9 including means for rotating said cam means incident to imparting sliding movement to said rod.
11. A top feed mechanism comprising a top feed bar adapted to be mounted below the horizontal plane of an associated sewing machine throat plate, means for imparting lift and feed motions to said top feed bar, a feed dog, means articulately mounting said feed dog upon said top feed bar, said mounting means including a pivotally mounted arm carrying said feed dog for pivotal movement relative to said feed bar, an actuator rod connected to said arm, means for moving said rod to pivot said arm and the feed dog carried thereby away from its fabric engaging position, means carried by said feed bar mounting said rod for sliding movement relative thereto, means carried by said rod and cooperative with said rod mounting means for limiting the movement of said rod in a first direction, and means for biasing said rod for movement in said first direction.
12. A feed mechanism for a sewing machine comprising a main feed bar and a top feed bar carrying respective main and top feed dogs, means for imparting feed motion to said feed bars, means for imparting lift motion to said feed bars, said lift motion imparting means being defined by first and second eccentric means coupled to said main and top feed bars respectively, one of said lift motion imparting eccentric means being carried by and surrounding the other of said lift motion imparting eccentric means, and said first and second eccentric means being generally 180° out of phase with each other whereby said feed dogs move toward each other to grip fabric therebetween during the feed cycle and move away from each other to release fabric incident to the return cycle.
13. The feed mechanism as defined in claim 12 including a rotatable shaft, and said first and second eccentric means are commonly actuated by said rotatable shaft.
14. The feed mechanism as defined in claim 13 wherein at least one of said first and second eccentric means is fixedly secured to said rotatable shaft.
15. The feed mechanism as defined in claim 12 wherein said feed motion imparting means is defined by third and fourth eccentric means coupled to said main and top feed bars respectively, and the eccentricities of said third and fourth eccentric means being generally similar and in phase with each other whereby multiply fabric pieces are fed evenly by said main and top feed dogs.
16. The feed mechanism as defined in claim 15 including a rotatable shaft having an eccentric portion, and said third and fourth eccentric means are commonly actuated by said eccentric portion.
17. A feed mechanism for a sewing machine comprising a main feed bar and a top feed bar carrying respective main and top feed dogs, means for imparting feed motion to said feed bars, means for imparting lift motion to said feed bars, said lift motion imparting means being defined by first and second eccentric means coupled to said main and top feed bars respectively, said first and second eccentric means being generally 180 degrees out of phase with each other whereby said feed dogs move toward each other to grip fabric therebetween during the feed cycle and move away from each other to release fabric incident to the return cycle, said feed motion imparting means is defined by third and fourth eccentric means coupled to said main and top feed bars respectively, the eccentricities of said third and fourth eccentric means being generally similar and in phase with each other whereby multiply fabric pieces are fed evenly by said main and top feed dogs, rotatable shaft having an eccentric portion, and said third and fourth eccentric means are commonly actuated by said eccentric portion, said rotatable shaft includes another eccentric portion, and said first and second eccentric means are commonly actuated by said last-mentioned eccentric portion.
18. The top feed mechanism as defined in claim 1 wherein said top feed bar and said articulate mounting means are disposed below the plane of engagement of said top and main feed dogs.
1. A top feed mechanism for sewing machines comprising a top feed bar and a main feed bar, means articulately mounting a top feed dog upon said top feed bar, means mounting a main feed dog upon said main feed bar, first means for imparting lift and feed motions to said main feed bar, second means for imparting lift and feed motions to said top feed bar, lift imparting portions of said first and second means being directionally in phase whereby said feed dogs move toward and away from each other in substantial unison during respective feed and retract cycles of said feed bars, and common drive means for imparting motion to said lift imparting portions.
2. The top feed mechanism as defined in claim 1 including means for biasing said top feed dog toward its fabric engaging position.
3. The top feed mechanism as defined in claim 1 including means for biasing said top feed dog toward its fabric engaging position, and means for adjusting said biasing means to regulate the force applied to fabric by said top feed dog.
4. The top feed mechanism as defined in claim 1 including means for camming said top feed dog away from its fabric engaging position.
5. The top feed mechanism as defined in claim 1 including means for limiting the movement of said top feed dog between fabric engaging and fabric disengaging positions thereof.
6. The top feed mechanism as defined in claim 1 wherein said mounting means includes means for pivotal movement of said top feed dog relative to said feed bar.
7. The top feed mechanism as defined in claim 1 wherein said mounting means includes a pivotally mounted arm carrying said top feed dog for pivotal movement relative to said top feed bar, an actuator rod connected to said arm, and means for moving said rod to pivot said arm and the top feed dog carried thereby away from its fabric engaging position.
8. The top feed mechanism as defined in claim 7 including means carried by said top feed bar mounting said rod for sliding movement relative thereto.
9. A top feed mechanism comprising a top feed bar adapted to be mounted below the horizontal plane of an associated sewing machine throat plate, means for imparting lift and feed motions to said top feed bar, a feed dog, means articulately mounting said feed dog upon said top feed bar, said mounting means including a pivotally mounted arm carrying said feed dog for pivotal movement relative to said feed bar, an actuator rod connected to said arm, means for moving said rod to pivot said arm and the feed dog carried thereby away from its fabric engaging position, means carried by said feed bar mounting said rod for sliding movement relative thereto, and said rod moving means includes cam means for imparting sliding movement to said rod.
10. The top feed mechanism as defined in claim 9 including means for rotating said cam means incident to imparting sliding movement to said rod.
11. A top feed mechanism comprising a top feed bar adapted to be mounted below the horizontal plane of an associated sewing machine throat plate, means for imparting lift and feed motions to said top feed bar, a feed dog, means articulately mounting said feed dog upon said top feed bar, said mounting means including a pivotally mounted arm carrying said feed dog for pivotal movement relative to said feed bar, an actuator rod connected to said arm, means for moving said rod to pivot said arm and the feed dog carried thereby away from its fabric engaging position, means carried by said feed bar mounting said rod for sliding movement relative thereto, means carried by said rod and cooperative with said rod mounting means for limiting the movement of said rod in a first direction, and means for biasing said rod for movement in said first direction.
12. A feed mechanism for a sewing machine comprising a main feed bar and a top feed bar carrying respective main and top feed dogs, means for imparting feed motion to said feed bars, means for imparting lift motion to said feed bars, said lift motion imparting means being defined by first and second eccentric means coupled to said main and top feed bars respectively, one of said lift motion imparting eccentric means being carried by and surrounding the other of said lift motion imparting eccentric means, and said first and second eccentric means being generally 180° out of phase with each other whereby said feed dogs move toward each other to grip fabric therebetween during the feed cycle and move away from each other to release fabric incident to the return cycle.
13. The feed mechanism as defined in claim 12 including a rotatable shaft, and said first and second eccentric means are commonly actuated by said rotatable shaft.
14. The feed mechanism as defined in claim 13 wherein at least one of said first and second eccentric means is fixedly secured to said rotatable shaft.
15. The feed mechanism as defined in claim 12 wherein said feed motion imparting means is defined by third and fourth eccentric means coupled to said main and top feed bars respectively, and the eccentricities of said third and fourth eccentric means being generally similar and in phase with each other whereby multiply fabric pieces are fed evenly by said main and top feed dogs.
16. The feed mechanism as defined in claim 15 including a rotatable shaft having an eccentric portion, and said third and fourth eccentric means are commonly actuated by said eccentric portion.
17. A feed mechanism for a sewing machine comprising a main feed bar and a top feed bar carrying respective main and top feed dogs, means for imparting feed motion to said feed bars, means for imparting lift motion to said feed bars, said lift motion imparting means being defined by first and second eccentric means coupled to said main and top feed bars respectively, said first and second eccentric means being generally 180 degrees out of phase with each other whereby said feed dogs move toward each other to grip fabric therebetween during the feed cycle and move away from each other to release fabric incident to the return cycle, said feed motion imparting means is defined by third and fourth eccentric means coupled to said main and top feed bars respectively, the eccentricities of said third and fourth eccentric means being generally similar and in phase with each other whereby multiply fabric pieces are fed evenly by said main and top feed dogs, rotatable shaft having an eccentric portion, and said third and fourth eccentric means are commonly actuated by said eccentric portion, said rotatable shaft includes another eccentric portion, and said first and second eccentric means are commonly actuated by said last-mentioned eccentric portion.
18. The top feed mechanism as defined in claim 1 wherein said top feed bar and said articulate mounting means are disposed below the plane of engagement of said top and main feed dogs.
Description:
Many years ago it was found that conventional feed dogs which operated only on the underside of fabric were inadequate when it became necessary to feed an upper layer of fabric in exact synchronism with a lower layer in order to maintain the layers in fixed relationship to each other during a sewing operation. Top feed mechanisms of various types were therefore continuously developed to produce simultaneous synchronous movement of top and main feed dogs so that multiply fabric workpieces could be fed together in the absence of slippage during a sewing operation. One such mechanism is disclosed in commonly assigned U.S. Pat. No. 1,995,945 in the name of Charles F. Rubel et al., issued Mar. 26, 1935. Of course, since the issue of the latter-noted patent, more sophisticated mechanisms have been designed and the following disclosure relates particularly to a novel top feed mechanism for an overedge sewing machine of the type disclosed in U.S. Pat. No. 2,704,042, issued in the name of Ned L. Wallenberg et al. on Mar. 15, 1959, and assigned to the present assignee. Machines of this type have been used for cord welting slip covers, seaming pile linings with satin sleeves for the linings of men's raincoats, and similar multiply sewing operations.
Primary among the objects of the top feed mechanism of this invention beyond the adaptability thereof for the particular machine disclosed in the latter-noted Wallenberg et al. patent is the simplicity of converting such overedge machines to include the top feed mechanism, simplicity of operation of the top feed mechanism, and the general foolproof operability thereof irrespective of the different types of fabrics adapted to be sewn thereby.
The top feed mechanism includes a feed bar to which is imparted lift and feed motions by appropriate eccentrics, a top feed dog, and means articulately mounting the top feed dog to the top feed bar to permit the feed dog to automatically move away from an associated main feed dog when passing over a seam or other obstruction during a sewing operation while still achieving a feeding function in conjunction with the main feed dog.
A further object of this invention is to provide a novel top feed mechanism of the type described wherein means are provided for biasing the top feed dog toward its fabric engaging position, and means for adjusting the biasing means to regulate the force applied to the fabric by the top feed dog during a sewing operation to adapt the top feed mechanism for sewing different types, thicknesses, etc., of fabric.
Yet another object of this invention is to provide a novel top feed mechanism of the type described wherein means are provided for camming the top feed dog away from its fabric engaging position simultaneously with the lifting of an associated presser foot to facilitate the removal and/or introduction of fabric relative to the feed mechanism.
Another object of this invention is to provide a novel top feed mechanism in which the top feed dog mounting means includes a pivotally mounted arm carrying the feed dog for pivotal movement relative to the top feed bar, an actuator rod connected to the arm, and means for moving the rod to pivot the arm and the feed dog carried thereby away from its fabric engaging position, the last mentioned means being a cam rotatable against the rod to impart sliding movement to the latter and thus pivot the top feed dog in a direction away from the main feed dog and its associated throat plate.
A further object of this invention is to provide a novel feed mechanism of the type described wherein the associated sewing machine includes a main feed bar carrying a main feed dog, and means are provided for imparting lift motion to the feed bars in the form of first and second eccentric means, and the first and second eccentric means are generally 180° out of phase with each other whereby the feed dogs move toward each other to grip fabric therebetween during the feed cycle and move away from each other to release fabric incident to the return cycle of the mechanism.
Yet another object of this invention is to provide a novel feed mechanism of the type described including feed motion imparting means for moving the feed bars, the feed motion imparting means being defined by third and fourth eccentric means coupled to the main and top feed bars, and the eccentricities of the third and fourth eccentric means being generally similar and in phase with each other whereby multiply fabric pieces are fed evenly by the main and top feed dogs.
With the above and other objects in view that will hereinafter appear, the nature of the invention will be more clearly understood by reference to the following detailed description, the appended claimed subject matter, and the several views illustrated in the accompanying drawings.
In the drawings:
FIG. 1 is an end elevational view of a sewing machine with portions thereof broken away for clarity, and illustrates a top feed dog carried by an arm pivotally mounted upon a support bracket of a top feed bar, and a spring biased cam operated actuating rod for moving the top feed dog away from the throat plate simultaneously with the lifting of an associated presser plate.
FIG. 2 is a fragmentary vertical sectional view taken generally along line 2--2 of FIG. 1, and illustrates two eccentric portions of a crankshaft for imparting lifting and feed motions to the top and main feed bars.
FIG. 3 is a fragmentary top perspective view of the machine looking downwardly in FIG. 1, and illustrates the general position of the top feed mechanism above and in alignment with the top feed bar.
FIG. 4 is a fragmentary elevational view of the rear of the sewing machine as viewed from left-to-right in FIG. 1, and illustrates a treadle operated link for rotating a plate having a cam surface for imparting motion to the actuator rod and pivoting the top feed dog simultaneously with the lifting of the presser foot.
FIG. 5 is a sectional view taken generally along line 5--5 of FIG. 3, and more clearly illustrates additional details of the top feed mechanism.
FIG. 6 is an enlarged fragmentary sectional view taken generally along the line 6--6 of FIG. 5 and more clearly illustrates the manner in which the top feed dog arm is articulately connected to the top feed bar and to the associated lifting rod.
FIG. 7 is an enlarged fragmentary sectional view taken generally along line 7--7 of FIG. 5, and illustrates details of a mounting collar for the actuating rod.
Referring to the drawings in detail, the sewing machine (unnumbered) illustrated and most of the mechanisms thereof are similar to that illustrated and described in the aforementioned patent to Wallenberg et al., and thus the present description will pertain only to the novel top feed mechanism therefor, and only so much of the machine and its components as are necessary for a complete understanding of the top feed mechanism.
The sewing machine includes a frame 10 having a crankshaft 11 journaled in suitable bearings 12, 13 (FIG. 2), and similar suitable bearings (not shown) provided at the right (unillustrated) end of the frame 10, as viewed in FIG. 2. Also, within the machine frame 10, and directly above the crankshaft 11, there is a needle driving shaft 14 journaled near its end (unnumbered) in a bearing 15. A bearing (not shown) is also provided at the right end of the needle driving shaft, again as viewed in FIG. 2 though not illustrated therein.
The crankshaft 11 extends outwardly of the machine frame 10, and the end portion thereof projecting outwardly includes two eccentric portions 16, 17 and a threaded terminal end 18. The eccentric portion 16 is the feed stroke eccentric and the eccentric portion 17 is the feed lift eccentric. The feed stroke eccentric 16 has a slightly larger eccentricity than the feed lift eccentric 17, while the threaded terminal end 18 is concentric with the main portion (unnumbered) of the crankshaft 11.
The feed lift eccentric portion 17 carries eccentric means in the form of a top feed lift eccentric 19 and a main feed lift block 20. The top feed lift eccentric 19 is secured by a screw (unnumbered) to the eccentric portion 17, while the main feed lift block 20 is loose on the eccentric portion 17 allowing the eccentric portion 17 to rotate freely in the main feed lift block 20. A forked front portion 21 of a top feed bar 22 surrounds the top feed lift eccentric 19. Adjacent the top feed bar 22 and to the left thereof, as viewed in FIG. 2, is a main feed bar 23. The main feed bar 23 similarly has a forked front portion 24 which surrounds the main feed lift block 20. The two feed bars extend toward the rear of the machine frame 10, and at their rear ends are supported by guide blocks 25, 26 carried by an eccentric stud 27. The eccentric stud 27 is secured in an upstanding portion 28 of the machine frame 10. The guide blocks 25, 26 are received in forked portions 29, 30 at the rear end of each of the feed bars 22, 23, respectively.
The eccentric portion 16 of the crankshaft 11 carries two feed stroke eccentrics 31, 32 fixed in position upon the eccentric portion 16 by a key 33 (FIG. 2). The two feed stroke eccentrics 31, 32 are held on the eccentric portion 16 by a washer 34 and a nut 35 secured to the threaded end 18. The outermost feed stroke eccentric 31 drives the main feed bar 23, and the inside feed stroke eccentric 32 drives the top feed bar 22. Drive means for the top feed bar 22 consists of a driving link or crank 36 surrounding the feed stroke eccentric at its forward end (unnumbered), while the rear end (also unnumbered) of the link 36 is connected to the top feed bar 22 by a feed driving stud 37 (FIG. 1) held in place by a nut 38. Drive means for the main feed bar 23 consists of a shorter driving link or crank 39 surrounding the feed stroke eccentric 31 (FIG. 1) at its forward end (unnumbered), while the rear end (also unnumbered) of the link 39 is connected to the main feed bar 23 by a feed driving stud 40 which passes from the main feed bar 23 through a clearance hole 41 in the driving link 36 and is held fast upon the driving link 39 by a nut 42.
A feed dog 43 is secured by a screw 44 to the main feed bar 23. The main feed bar and the feed dog 43 carried thereby operate in the manner described in the Wallenberg et al. patent, and a further description thereof is considered unnecessary for a complete understanding of this invention.
The top feed bar 22 carries the top feed mechanism of this invention including a feed dog carrier mounting bracket 45 secured by a screw 46 in a slot (unnumbered) at the front end of the top feed bar 22. The top feed dog carrier mounting bracket 45 extends upwardly and rearwardly, as viewed in FIG. 1, and is provided with a threaded hole (unnumbered) at its upper end. A shoulder screw 47 cooperates with the threaded hole for mounting a top feed dog carrier or arm 48 intermediate its ends upon the bracket 45. The top feed dog carrier 48 is thus pivotally mounted by the screw 47 for movement from the position shown in FIG. 1 to a second position (not shown) in a counterclockwise direction. As shown in FIG. 1, the arm 48 is disposed along with a top feed dog 50 in the fabric feeding position while when pivoted counterclockwise, the feed dog 50 is lifted away from the fabric and the main feed dog 43 to prevent fabric feed and permit either the introduction or removal of fabric between the feed dogs 43, 50. The feed dog arm 48 includes a vertical slot 49 which receives an end (unnumbered) of the feed dog 50 which is secured in the slot 49 by a screw 51.
An opposite end of the feed dog arm 48 extends downwardly from the pivot point defined by the screw 47 and includes a bore 52 into which is received from the inside of the arm 48 a lifter rod 53. The rod is held in position within the bore 52 by a snap ring 54. The rod 53 extends parallel to and in alignment above the top feed bar 22. The rod 53 passes through mounting means in the form of a guide bearing 55 mounted by screws 56 (FIG. 7) at the rear of the top feed bar 22. Locating means 57, 59 in the form of collars are mounted on the rod 53 to the left and right, respectively, of the guide bearing 55. Biasing means in the form of a spring 58 is contained between the collar 57 and the guide bearing 55 and functions to bias the rod 53 to the left as viewed in FIG. 1 thereby continually tending to pivot the arm 48 and the top feed dog 50 carried thereby in a clockwise direction. The collar 59 limits the movement of the rod 53 to the left, as also viewed in FIG. 1 of the drawings. Therefore, the cooperation of the spring 58 pushing the rod 53 to the left and the collar 59 holding the rod 53 in the position shown in FIG. 1 maintains the top feed dog 50 in a stationary position relative to the top feed bar 22 during the operation of the latter. However, the spring 58 will yield allowing the top feed dog 50 and the arm 48 to pivot about the axis of the screw 47 and thus rise when passing over a seam or other obstruction on the fabric during a sewing operation. Also, the pressure applied by the top feed dog 50 upon the fabric can be varied by controlling the tension of the spring 58 simply by relatively adjusting the collar 57 and locking the same at any position along the rod 53 by the illustrated though unnumbered set screws. If, for example, the collar 57 is moved to the right as viewed in FIG. 1, the biasing force of the spring 58 is increased while opposite movement results in a decrease of pressure applied by the top feed dog 50 upon the fabric.
The sewing machine includes a presser foot lifting mechanism similar to that illustrated and disclosed in the Wallenberg et al. patent, and operates in substantially the same manner. However, to the existing mechanism there is added a top feed dog lifter plate 60 (FIG. 4) extending oppositely from the presser foot lifter lever 61. The lifter plate or lever 60 is mounted for pivotal movement on a shoulder screw 62. An end (unnumbered) of the lever 60 is fixed to the lifter lever 61 by a rod 70 passing through bores in both the plate 60 and the lever 61. The opposite end of the plate 60 extends upwardly and toward the terminal rear end of the lifter rod 53, as is best illustrated in FIGS. 3 and 4. The end of the plate 60 is bent to form camming means in the form of a camming surface 63.
As the presser foot lifter lever 61 is pulled down by a treadle or knee press, the plate 60 will rotate in a counterclockwise direction, as is viewed in FIG. 4, and the camming surface 63 will progressively push the rod 53 to the right, as viewed in FIG. 1, resulting in the lifting of the top feed dog 50 away from a throat plate 64 and the main feed dog 43 in order to facilitate the insertion or removal of the fabric. At the same time, the rod 70 being pulled down by the lifter lever 61 will in turn pull down a lever 65 having an end (unnumbered) connected to a shaft 66 causing the rotation of the latter in a counterclockwise direction, as viewed in FIG. 1. The shaft 66 is connected by an arm 71 to the presser foot 67 thereby resulting in the lifting of the presser foot 67 away from the throat plate 64 simultaneously with a like lifting of the top feed dog 50.
Reference is now made particularly to FIGS. 2 and 5 wherein it will be noted that the top feed lift eccentric 19 has its eccentricity substantially 180° out of phase from that of the eccentric portion 17 which is used for lifting the main feed bar 23. Thus the main feed dog 23 and the top feed dog 22 will be operating opposite to each other such that as the main feed dog 23 is rising the top feed dog 22 will be falling to meet the main feed dog resulting in a clamping action for feeding the plies of fabric evenly. Likewise, release of the fabric at the end of the feed stroke will take place by the simultaneous movement of the main and top feed dogs away from each other.
The feed stroke eccentrics 31, 32 are of substantially the same eccentricity in order to feed the plies of fabric evenly. However, the eccentrics 31, 32 may be changed or replaced by larger or smaller eccentrics in order to obtain a longer or shorter feed stroke. Furthermore, it is to be understood that the top feed dog 50 could be of a shape other than that illustrated in the drawings and could, for example, be longer in order to be closer to the rear of the presser foot 67, or it could be wider to the right side, as viewed in FIG. 3, and closer to the needle line, or it could include a groove or cutout to allow for piping on the fabric to pass therethrough during a sewing operation.
As in the Wallenberg et al. patent, the machine further includes a needle carrier 72 and a needle 74 which are oscillated by the needle driving shaft which is in turn driven from the main crankshaft 11 in a manner disclosed in the latter noted patent.
While preferred forms and arrangements of parts have been shown in illustrating the invention, it is to be clearly understood that various changes in details and arrangement of parts may be made without departing from the spirit and scope of this disclosure.
Primary among the objects of the top feed mechanism of this invention beyond the adaptability thereof for the particular machine disclosed in the latter-noted Wallenberg et al. patent is the simplicity of converting such overedge machines to include the top feed mechanism, simplicity of operation of the top feed mechanism, and the general foolproof operability thereof irrespective of the different types of fabrics adapted to be sewn thereby.
The top feed mechanism includes a feed bar to which is imparted lift and feed motions by appropriate eccentrics, a top feed dog, and means articulately mounting the top feed dog to the top feed bar to permit the feed dog to automatically move away from an associated main feed dog when passing over a seam or other obstruction during a sewing operation while still achieving a feeding function in conjunction with the main feed dog.
A further object of this invention is to provide a novel top feed mechanism of the type described wherein means are provided for biasing the top feed dog toward its fabric engaging position, and means for adjusting the biasing means to regulate the force applied to the fabric by the top feed dog during a sewing operation to adapt the top feed mechanism for sewing different types, thicknesses, etc., of fabric.
Yet another object of this invention is to provide a novel top feed mechanism of the type described wherein means are provided for camming the top feed dog away from its fabric engaging position simultaneously with the lifting of an associated presser foot to facilitate the removal and/or introduction of fabric relative to the feed mechanism.
Another object of this invention is to provide a novel top feed mechanism in which the top feed dog mounting means includes a pivotally mounted arm carrying the feed dog for pivotal movement relative to the top feed bar, an actuator rod connected to the arm, and means for moving the rod to pivot the arm and the feed dog carried thereby away from its fabric engaging position, the last mentioned means being a cam rotatable against the rod to impart sliding movement to the latter and thus pivot the top feed dog in a direction away from the main feed dog and its associated throat plate.
A further object of this invention is to provide a novel feed mechanism of the type described wherein the associated sewing machine includes a main feed bar carrying a main feed dog, and means are provided for imparting lift motion to the feed bars in the form of first and second eccentric means, and the first and second eccentric means are generally 180° out of phase with each other whereby the feed dogs move toward each other to grip fabric therebetween during the feed cycle and move away from each other to release fabric incident to the return cycle of the mechanism.
Yet another object of this invention is to provide a novel feed mechanism of the type described including feed motion imparting means for moving the feed bars, the feed motion imparting means being defined by third and fourth eccentric means coupled to the main and top feed bars, and the eccentricities of the third and fourth eccentric means being generally similar and in phase with each other whereby multiply fabric pieces are fed evenly by the main and top feed dogs.
With the above and other objects in view that will hereinafter appear, the nature of the invention will be more clearly understood by reference to the following detailed description, the appended claimed subject matter, and the several views illustrated in the accompanying drawings.
In the drawings:
FIG. 1 is an end elevational view of a sewing machine with portions thereof broken away for clarity, and illustrates a top feed dog carried by an arm pivotally mounted upon a support bracket of a top feed bar, and a spring biased cam operated actuating rod for moving the top feed dog away from the throat plate simultaneously with the lifting of an associated presser plate.
FIG. 2 is a fragmentary vertical sectional view taken generally along line 2--2 of FIG. 1, and illustrates two eccentric portions of a crankshaft for imparting lifting and feed motions to the top and main feed bars.
FIG. 3 is a fragmentary top perspective view of the machine looking downwardly in FIG. 1, and illustrates the general position of the top feed mechanism above and in alignment with the top feed bar.
FIG. 4 is a fragmentary elevational view of the rear of the sewing machine as viewed from left-to-right in FIG. 1, and illustrates a treadle operated link for rotating a plate having a cam surface for imparting motion to the actuator rod and pivoting the top feed dog simultaneously with the lifting of the presser foot.
FIG. 5 is a sectional view taken generally along line 5--5 of FIG. 3, and more clearly illustrates additional details of the top feed mechanism.
FIG. 6 is an enlarged fragmentary sectional view taken generally along the line 6--6 of FIG. 5 and more clearly illustrates the manner in which the top feed dog arm is articulately connected to the top feed bar and to the associated lifting rod.
FIG. 7 is an enlarged fragmentary sectional view taken generally along line 7--7 of FIG. 5, and illustrates details of a mounting collar for the actuating rod.
Referring to the drawings in detail, the sewing machine (unnumbered) illustrated and most of the mechanisms thereof are similar to that illustrated and described in the aforementioned patent to Wallenberg et al., and thus the present description will pertain only to the novel top feed mechanism therefor, and only so much of the machine and its components as are necessary for a complete understanding of the top feed mechanism.
The sewing machine includes a frame 10 having a crankshaft 11 journaled in suitable bearings 12, 13 (FIG. 2), and similar suitable bearings (not shown) provided at the right (unillustrated) end of the frame 10, as viewed in FIG. 2. Also, within the machine frame 10, and directly above the crankshaft 11, there is a needle driving shaft 14 journaled near its end (unnumbered) in a bearing 15. A bearing (not shown) is also provided at the right end of the needle driving shaft, again as viewed in FIG. 2 though not illustrated therein.
The crankshaft 11 extends outwardly of the machine frame 10, and the end portion thereof projecting outwardly includes two eccentric portions 16, 17 and a threaded terminal end 18. The eccentric portion 16 is the feed stroke eccentric and the eccentric portion 17 is the feed lift eccentric. The feed stroke eccentric 16 has a slightly larger eccentricity than the feed lift eccentric 17, while the threaded terminal end 18 is concentric with the main portion (unnumbered) of the crankshaft 11.
The feed lift eccentric portion 17 carries eccentric means in the form of a top feed lift eccentric 19 and a main feed lift block 20. The top feed lift eccentric 19 is secured by a screw (unnumbered) to the eccentric portion 17, while the main feed lift block 20 is loose on the eccentric portion 17 allowing the eccentric portion 17 to rotate freely in the main feed lift block 20. A forked front portion 21 of a top feed bar 22 surrounds the top feed lift eccentric 19. Adjacent the top feed bar 22 and to the left thereof, as viewed in FIG. 2, is a main feed bar 23. The main feed bar 23 similarly has a forked front portion 24 which surrounds the main feed lift block 20. The two feed bars extend toward the rear of the machine frame 10, and at their rear ends are supported by guide blocks 25, 26 carried by an eccentric stud 27. The eccentric stud 27 is secured in an upstanding portion 28 of the machine frame 10. The guide blocks 25, 26 are received in forked portions 29, 30 at the rear end of each of the feed bars 22, 23, respectively.
The eccentric portion 16 of the crankshaft 11 carries two feed stroke eccentrics 31, 32 fixed in position upon the eccentric portion 16 by a key 33 (FIG. 2). The two feed stroke eccentrics 31, 32 are held on the eccentric portion 16 by a washer 34 and a nut 35 secured to the threaded end 18. The outermost feed stroke eccentric 31 drives the main feed bar 23, and the inside feed stroke eccentric 32 drives the top feed bar 22. Drive means for the top feed bar 22 consists of a driving link or crank 36 surrounding the feed stroke eccentric at its forward end (unnumbered), while the rear end (also unnumbered) of the link 36 is connected to the top feed bar 22 by a feed driving stud 37 (FIG. 1) held in place by a nut 38. Drive means for the main feed bar 23 consists of a shorter driving link or crank 39 surrounding the feed stroke eccentric 31 (FIG. 1) at its forward end (unnumbered), while the rear end (also unnumbered) of the link 39 is connected to the main feed bar 23 by a feed driving stud 40 which passes from the main feed bar 23 through a clearance hole 41 in the driving link 36 and is held fast upon the driving link 39 by a nut 42.
A feed dog 43 is secured by a screw 44 to the main feed bar 23. The main feed bar and the feed dog 43 carried thereby operate in the manner described in the Wallenberg et al. patent, and a further description thereof is considered unnecessary for a complete understanding of this invention.
The top feed bar 22 carries the top feed mechanism of this invention including a feed dog carrier mounting bracket 45 secured by a screw 46 in a slot (unnumbered) at the front end of the top feed bar 22. The top feed dog carrier mounting bracket 45 extends upwardly and rearwardly, as viewed in FIG. 1, and is provided with a threaded hole (unnumbered) at its upper end. A shoulder screw 47 cooperates with the threaded hole for mounting a top feed dog carrier or arm 48 intermediate its ends upon the bracket 45. The top feed dog carrier 48 is thus pivotally mounted by the screw 47 for movement from the position shown in FIG. 1 to a second position (not shown) in a counterclockwise direction. As shown in FIG. 1, the arm 48 is disposed along with a top feed dog 50 in the fabric feeding position while when pivoted counterclockwise, the feed dog 50 is lifted away from the fabric and the main feed dog 43 to prevent fabric feed and permit either the introduction or removal of fabric between the feed dogs 43, 50. The feed dog arm 48 includes a vertical slot 49 which receives an end (unnumbered) of the feed dog 50 which is secured in the slot 49 by a screw 51.
An opposite end of the feed dog arm 48 extends downwardly from the pivot point defined by the screw 47 and includes a bore 52 into which is received from the inside of the arm 48 a lifter rod 53. The rod is held in position within the bore 52 by a snap ring 54. The rod 53 extends parallel to and in alignment above the top feed bar 22. The rod 53 passes through mounting means in the form of a guide bearing 55 mounted by screws 56 (FIG. 7) at the rear of the top feed bar 22. Locating means 57, 59 in the form of collars are mounted on the rod 53 to the left and right, respectively, of the guide bearing 55. Biasing means in the form of a spring 58 is contained between the collar 57 and the guide bearing 55 and functions to bias the rod 53 to the left as viewed in FIG. 1 thereby continually tending to pivot the arm 48 and the top feed dog 50 carried thereby in a clockwise direction. The collar 59 limits the movement of the rod 53 to the left, as also viewed in FIG. 1 of the drawings. Therefore, the cooperation of the spring 58 pushing the rod 53 to the left and the collar 59 holding the rod 53 in the position shown in FIG. 1 maintains the top feed dog 50 in a stationary position relative to the top feed bar 22 during the operation of the latter. However, the spring 58 will yield allowing the top feed dog 50 and the arm 48 to pivot about the axis of the screw 47 and thus rise when passing over a seam or other obstruction on the fabric during a sewing operation. Also, the pressure applied by the top feed dog 50 upon the fabric can be varied by controlling the tension of the spring 58 simply by relatively adjusting the collar 57 and locking the same at any position along the rod 53 by the illustrated though unnumbered set screws. If, for example, the collar 57 is moved to the right as viewed in FIG. 1, the biasing force of the spring 58 is increased while opposite movement results in a decrease of pressure applied by the top feed dog 50 upon the fabric.
The sewing machine includes a presser foot lifting mechanism similar to that illustrated and disclosed in the Wallenberg et al. patent, and operates in substantially the same manner. However, to the existing mechanism there is added a top feed dog lifter plate 60 (FIG. 4) extending oppositely from the presser foot lifter lever 61. The lifter plate or lever 60 is mounted for pivotal movement on a shoulder screw 62. An end (unnumbered) of the lever 60 is fixed to the lifter lever 61 by a rod 70 passing through bores in both the plate 60 and the lever 61. The opposite end of the plate 60 extends upwardly and toward the terminal rear end of the lifter rod 53, as is best illustrated in FIGS. 3 and 4. The end of the plate 60 is bent to form camming means in the form of a camming surface 63.
As the presser foot lifter lever 61 is pulled down by a treadle or knee press, the plate 60 will rotate in a counterclockwise direction, as is viewed in FIG. 4, and the camming surface 63 will progressively push the rod 53 to the right, as viewed in FIG. 1, resulting in the lifting of the top feed dog 50 away from a throat plate 64 and the main feed dog 43 in order to facilitate the insertion or removal of the fabric. At the same time, the rod 70 being pulled down by the lifter lever 61 will in turn pull down a lever 65 having an end (unnumbered) connected to a shaft 66 causing the rotation of the latter in a counterclockwise direction, as viewed in FIG. 1. The shaft 66 is connected by an arm 71 to the presser foot 67 thereby resulting in the lifting of the presser foot 67 away from the throat plate 64 simultaneously with a like lifting of the top feed dog 50.
Reference is now made particularly to FIGS. 2 and 5 wherein it will be noted that the top feed lift eccentric 19 has its eccentricity substantially 180° out of phase from that of the eccentric portion 17 which is used for lifting the main feed bar 23. Thus the main feed dog 23 and the top feed dog 22 will be operating opposite to each other such that as the main feed dog 23 is rising the top feed dog 22 will be falling to meet the main feed dog resulting in a clamping action for feeding the plies of fabric evenly. Likewise, release of the fabric at the end of the feed stroke will take place by the simultaneous movement of the main and top feed dogs away from each other.
The feed stroke eccentrics 31, 32 are of substantially the same eccentricity in order to feed the plies of fabric evenly. However, the eccentrics 31, 32 may be changed or replaced by larger or smaller eccentrics in order to obtain a longer or shorter feed stroke. Furthermore, it is to be understood that the top feed dog 50 could be of a shape other than that illustrated in the drawings and could, for example, be longer in order to be closer to the rear of the presser foot 67, or it could be wider to the right side, as viewed in FIG. 3, and closer to the needle line, or it could include a groove or cutout to allow for piping on the fabric to pass therethrough during a sewing operation.
As in the Wallenberg et al. patent, the machine further includes a needle carrier 72 and a needle 74 which are oscillated by the needle driving shaft which is in turn driven from the main crankshaft 11 in a manner disclosed in the latter noted patent.
While preferred forms and arrangements of parts have been shown in illustrating the invention, it is to be clearly understood that various changes in details and arrangement of parts may be made without departing from the spirit and scope of this disclosure.