US2153006A

US2153006A - Sewing machine for producing superposes stitches

Info

Publication number: US2153006A
Application number: US121993A
Authority: US
Inventors: Roseman Leo
Original assignee: Individual
Current assignee: Individual
Priority date: 1937-01-23
Filing date: 1937-01-23
Publication date: 1939-04-04
Anticipated expiration: 1956-04-04

Description

April 4, 1939. 1.. ROSEMAN 2,153,006

SEWING MACHINE FOR PRODUCING SUPERPOSED STITCHES Filed Jan. 25, 1957 10 Sheets-Shet 1 INVE OR I I T %RNEY April 4, 1939.

' L. ROSEMAN.

SEWING MACHINE FOR PRODUCING SUPERPOSED STITCHES Filed Jan. 25, 1957 10 Sheets-Sheet 2 lfllllilf 2 Z INVENTOR y BY XATTORNEY April 4, 1939. ROSEMAN 2,153,006

SEWING MACHINE FOR PRODUCING SUPER1?OSED STITCHES Filed Jan. 25, 1937 10 Sheets-Sheet s lNVENT E '1 AT RNEY April 4, 1 939. ROSEMAN 2,153,006

SEWING MACHINE FOR PRODUCING SUPERPOSED STITCHES Filed Jan. 23, 1937 lO-Sheets-Sheet 4 ORNEY April 4, 1939. -L. ROSEMAN 2,153,006

' SEWING MACHINE FQR PRODUCING suPERPosED STITCHES Filed Jan. 23, 1937 10 Sheets-Sheet 5 NVENTOR TORNEY p l 1939- L.. ROSEMAN 2,153,006

SEWING MACHINE FOR PRODUCING SUPERPOSED STITCHBS Filed Jan. 23, 1937 lOSheets-Sheet 6 ORNEY April 4, 1939. L. ROSEMAN 2,153,006

SEWING MACHINE FOR PRODUCING SUPERPOSED STITCHES Filed Jan. 23, 1957 10 SheetsSheet 2 VENTQR April 4,- '1939. ROSEMAN 2,153,006

SEWING MACHINE FOR PRODUCING SQPERPOSED STiTCHES Filed Jan..23, 193v IO-Sheets-Sheet s 2' QVENTOR I BY M I April 4, 1939. ROSEMAN' 2,153,005

SEWING MACHINE FOR PRODUCING SUPERPOSED STITCHES Filed Jan. 23, 1957 10 Sheets-Sheet 9 2 IQENTOR BY M QRNEY April 4, 1939. L, R$EM N 2,153,006

SEWING MACHINE FOR PRODUCING SUPERPOSED STITCHES Filed Jan. 23, 1957 1O Sheets-Sheet l0 fix) lgZVENTOR I A ORNEY Patented Apr. 4, 1939 UNITED STATES PATENT OFFICE- SEWING MACHINE FOR PRODUCING SUPERPOSED STITOHES Leo Roseman, Newark, N. J.

Application January 23, 1937, Serial No. 121,993

4 Claims.

This invention relates in general to a sewing machine having the needle bar movable back and forth in a plane parallel to the direction of movel rection of feed of the work or transversely of the work or zig-zag stitches, and also for forming jump or skip stitches between two adjacent series of superposed stitches, whereby the operations may be performed rapidly and automatically and 15 the formation of the stitches shall be extremely accurate.

A further'object is to provide such a machine.

whereby the length of running stitches canbe increased or decreased automatically by control 20 of said back and forth movement of the needle in conjunction with work feed mechanism.

The invention is especially useful in forming gaps between two pieces of material to receive fastener elements, with superposed stitches at the 25 ends of the gaps for reenforcing the work at those points and to permit the fasteners to be brought close to the edges of the pieces of material, for example as shown in my copending applications Serial No. 744,642 filed September 19, 1934, and

30 Serial No. 106,326 filed October 19, 1936. Also, the invention is contemplated for use in making tying stitches for securing snap fasteners on tape, for example as shown in my copending application Serial No. 92,711 filed July 27, 1936, where 35 the fastener elements have apertures and lines of stitches run longitudinally of the tape and series of superposed or tying stitches pass through said apertures and the tape in traversing relation to the fastener elements. 40 In known machines for making superposed tying stitches running in the direction of the work feed, for example as shown in my said application Serial No. 744,642 or in my Patent No. 2,052,896 dated September 1, 1936, the feed of the work 45 is periodically reversed, or the work is moved alternately manually or automatically in opposite ,Other prime objects of the present invention are to provide a novel and improved method of and machine for forming superposed stitches running in'the direction of normal feed of the work and without the necessity of reversing the 5 work feed or reciprocating the work; and thus to provide such a method and machine wherein the needle shall both reciprocate to pierce and withdraw from the work and move back and forth or oscillate in a plane parallel with the direction of feed of the work, and the reciprocation and back andforth movement of the needle shall be correlated'fwith the movement of the work feed mechanism to form superposed stitches.

Another object is to provide such a method and machine wherein the work shall be fed continuously step-by-step in the usual way, and the back and forth movement oroscillation of the needle shall be controlled to form superposed stitches during and without interruption or variation in the feeding of the work.

Further objects are to provide a method and machine of the general character described including the reciprocatory needle that is also movable back and forth, wherein the length of the stitches may be varied by control of the back and forth movement of the needle without change in the work feed; and also to provide a method and machine wherein the feed of the work shall be varied or interrupted during back and forth movement or oscillation of the needle to form the superposed stitches.

Another object is to provide a method and machine of the character described whereby jump stitches may be formed by back and forth movement of the needle in conjunction with normal feed of the work, without increasing or diminishing the length of a step of feed, and without preventing formation of a stitch.

A further object is to provide in such a machine novel and improved automatic means for controlling back and forth movement of the needle, and novel and improved automatic means for controlling feed of the work, both of which shall be simple, reliable and relatively inexpensive.

Other objects are to provide a method and machine of this character whereby a continuous line of stitches may be formed having spaced series of superposed stitches extending in the direction tain other results and advantages as will be brought out by the following description when read'in conjunction with the accompanying drawdifferent steps in the operation of the machine.

Figures 4A and 5A are schematic plan views of a portion of the work showing the operations performed by the machine with the parts in positions shown in the respective Figures 4 and 5. Figure 6 is an end elevation of a modified form of the machine with the cover plate. of the stitching head removed.

Figure 7 is an end elevation of the stitching head.

Figure 8 is a front elevation of the form of the machine shown in Figure 6.

Figure 9 is a vertical sectional view through the stitching head with the needle bar supporting bracket removed.

Figure 9A is a detached perspective view of a needle bar.

Figure 10 is a bottom plan view of a machine showing the feed driving mechanism.

Figure 11 is a plan view ofthe cam for oscilating the needle bar shown in Figures 6 to 10 inclusive.

Figure 12 is a fragmentary development cam surface shown in Figure 11.

Figure 13 is a view similar toFigure 11 showing the cam for controlling oscillation of the needle bar in the form of the invention shown in Figures 1 to 5 inclusive.

Figure 14 is a similar view of another modification of the cam for oscillating the needle.

Figure 15 is a plan view of the cam forconof the trolling operation of the work feed mechanism shown in Figures 1 to 5 inclusive.

Figure 16 is a plan view of the work feed cam corresponding to the modified needle oscillating cam shown in Figure 14.

Figure 17 is a composite schematic view showing the various steps of operationv of the machine shown in Figures 1 to, 5 inclusive.

Figure 18 is a similar view showing of operation of the machine shown in Figures 6 to 10 inclusive.

Figure 19 is a similar view showing the steps of operation of the other modified machine embodying the cams shown in Figures 14 and 16.

Figures 20 to 39 inclusive are schematic end elevations of the stitch forming mechanism and work showing the functions of the oscillating needle in the form of the machine shown in Figures 1 to 5 inclusive.

Figures 40 to 59 are similar views showing the functions of the oscillatingneedle in the form of the invention shown in Figures 6 to 9 inclusive,

and

Figures 60 to 79 inclusive are like views showing the functions of the oscillating'needle in the modified form of machine embodying the cams illustrated in Figures 14 and 16. v

Specifically describing the embodiment of the invention illustrated in Figures 1 to 5 inclusive the reference character A designates the bed plate of the machine which has the usual standard B thereon, formed with a goose neck C at a bobbin mechanism 0 of the steps one end of which is mounted the stitching head D. In the stitching head is a needle bar E which is mounted to move back and forth in a plane parallel to the direction of movement of the work. As shown (see Fig. 6), the needle bar is reciprocatory in a bracket F which is pivotallymounted at G to .swing about a horizontal axis, and the needle bar carries one or two needles H, as desired, which are caused to penetrate and withdraw from the work upon reciprocation of the needle bar in known manner. The needle bar may be driven in the usual way from the drive shaft I of the machine which is joumaled in the standard B and goose neck C, and as shown, the shaft I carries a disk K on which is a wrist pin L which is connected by a link M to a pin N on the needle bar. 7

With the needle bar and its needles cooperates the usual type, the needle bar, its operating devices and the bobbin and its cooperating parts, constituting a stitch anism for moving work through the stitch forming mechanism, that is, between the needles and the bobbins, and as shown, this work feed mechanism includes the usual presser foot PP and a feed dog P which is movable vertically and horizontally relatively to the usual throat plate 2 in the bed of the machine, the dog being raised through the throat plate Q and moved horizontally in one direction in engagement with the work to move the latter and then being lowered away from the work and being moved horizontally in the other direction to its init al position. The dog is operated from the driv shaft I of the machine and as shown is mounted on a link B. one end of which is bifurcated at S to embrace a cam T on a counter-shaft U joumaled in the bed plate of the machine. The other end of the link It is pivotally connected at V to a crank W on another countershaft X journaled in the bed of the machine. The counter-shaft U is rotated by a belt and pulley connection Y from the drive as shown in my copending application Serial No. 744,642-filed September 19, 1934. As shown, the

counter-shaft X has a pin I projecting laterally therefrom through a slot 2 in the bed plate of the machine, the end of the pin being arranged in an opening 3 in an actuating slide 4 so that the pin has a hinged or pivotal connection with the slide and reciprocation of the slide will cause rotation of the shaft alternately in opposite directions. The slide is mounted on the bed of the machine in suitable guides 5.

One end of the slide 4 has a pin and slot connection 6 with one end of a Iever'l which is pivotally mounted at 8 on a horizontal axis'on'a bracket 9 secured on the top of the bed A of the machine. A follower roller I0 is joumaled on an arm H on the lever I and cooperates with a cam AA, being held in engagement with the cam by a spring l2, so that the cam oscillates the lever 1 to cause reciprocation of the slide 4, 0scillation of the shaft X and reciprocating horizontal movement of the feed dog P. The form of the cam AA will be varied to correspond to the length, character and spacing oithe stitches to be produced as hereinafter described so as to move the work in one direction step-by-step and periodically momentarily interrupt movement of the work.

For oscillating or moving the needle bar back and forth in timed relation to the movement of the work feed mechanism and reciprocation of the needle bar, I have shown the bracket F (see Figures 4, 5 and 6) provided with a lateral pin l3 which is connected to a link I4 slidably mounted by a bolt and slot connection I5 in the stitching head D. The end of the link projects beyond the rear side of the stitching head and has a pin and slot connection IS with one end of a lever H which is pivotally mounted intermediate its ends at It? on a standard I!) secured to w the top of the bed A of the machine. The other cams.

end of the lever ll carries a follower roller 20 which follows a cam BB and is held in engagement with the cam by a tension spring 2!. The form of the cam BB will be varied to correspond to the length and timing of the oscillating movements desired in the needle bar, as hereinafter described, so as to move the needle bar back and forth in a plane parallel to the direction of movement of work by the work feed mechanism.

As shown, both cams AA and BB are mounted on an auxiliary shaft 22 that is journaled with its axis vertical in bearings 23 and. 24, and has a worm gear 25 which meshes with a worm 26 on the drive shaft 1. Preferably the ratio of the

gearing

25, 26 is such that the cam will be ro-- As shown, the machine so far described is adapted to form lines of stitches running longitudinally of the work and including spaced series of superposed stitches 217, and jump stitches 28 and running single stitches 29 between the series of superposed stitches (see Figures 17 and 20 to 39), Accordingly the work feed cam. AA shown in detail in Figure 15 includes a plurality of cam surfaces 30 and 3| and corresponding dwells 30A and MA. When the follower roller l0 moves from one of the dwells 3lA upon one of the cam surfaces 30 the feed dog P is reciprocated in the direction to feed the work to the left of Figure 3,

the cam T having previously raised the feed dog from the position shown in Figure 3 through the throat plate into engagement with the work; and as the roller it) leaves each dwell 30A at d passes over the cam surface 3| onto the dwell 3IA the feed dog is. moved in the opposite direction, the cam T'havi'ng previously lowered the feed dog away from the work. The cam also has two concentric dwells 32 for interrupting movement of the work during the formation of the two series of superposed stitches'at each end of each jump stitch 28, and between the dwells 32 are

cam surfaces

33 and 34 and corresponding dwells 33A and 34A for feeding the work a distance equal to two stitches for formation of the jump stitch 28. The number of the

surfaces

30 and 3! will be dependent upon the number of running stitches 29 to be made between the series of superposed stitches 21.

The corresponding needle bar oscillating cam BB has a plurality of cam surfaces 340 each corresponding -to one of the cam surfaces 30 0f the cam AA, for controlling the needle bar during the formation of-the running stitches 29 there being dwells 34! between the cam surfaces 340.

At one end of the series of cam surfaces 340 is a cam surface 35 and corresponding dwell 35A for permitting movement of the needle bar under the influence of the spring 2| in the direction corresponding to the direction of movement of the work for formation of one of the superposed stitches 2'! at one end of the jump stitch 28; and adjoining the dwell 35A is another cam surface 36 and corresponding dwell 36A for moving the needle bar in the other direction for forming another superposed stitch of said series. Adjacent the dwell 36A is a cam surface 31 and corresponding dwell 31A for moving the needle bar in the direction opposite the direction of movement of the work for forming the jump stitch, and adjacent the dwell 31A are the cam surfaces 38 and 39 and corresponding dwells 38A and 39A for moving the needle bar to form two of the superposed stitches atthe other end of the jump stitch.

In the operation of the machine, assuming that the machine is at the point of beginning the formation of the first series of superposed stitches 2?; the needle bar is in its central or neutral position after formation of the first stitch2lA of the series of superposed stitches, as shown in Figure 20, with the needle withdrawn from the work. At this point the feed mechanism follower roller I0 is in engagement with one of the dwells 32 ,of the cam AA so that the feed dog P is stationary and out of contact with the work as shown in Figure 3. The cams rotate in the direction of the arrows of Figures 13 and 15, and the needle bar actuating roller 22 then is engaged by the cam surface 35 so as to swing the needle bar backwardly or in the direction of the normal feed of the work, a distance equal to the length of one stitch as shown in Figure 21, whereupon the needle is caused by the drive shaft I and link M to penetrate the work to complete the second superposed stitch ZlB as shown in Figure 22. Thereupon the roller 20 is engaged by the cam surface 36 which swings the needle bar forwardly the same distance whereupon the ,needle again penetrates the work to form the third superposed stitch 210 as shown in Figure 25." The needle bar is then withdrawn from the work and is in its neutral or initial position and continued movement of the cams causes engagement of the cam surface 31 with the roller 20' so as to swing the needle bar forwardly or in a direction opposite that of movement of-the work a distance equal to the length of one stitch or one step of feeding movement of the feed dog. Simultaneously with the swinging of the needle, the feed dog is actuated to move the work forwardly one step by one cam surface 33 of the cam AA as shown in Figure 27. The needle is then caused to penetrate and withdraw from the work as shown in Figures 28 and 29 to complete the jump stitch 28', equal in length to two normal stitches. Thereupon the work is advanced one step by the other cam surface 33 and the needle penetrates and withdraws from the work to form the first stitch 211) of the other series of superposed stitches at the end of the jump stitch 28 as shown in Figures 30 to 32. Then the movement/of the work feed mechanism is interrupted by the cam dwell 32 and the needle bar is swung rearwardly in the direction of normal feed of the work by cam surface 38 and penetrates and withdraws from the work to form the second stitch 21E as shown in Figures 33 to 35 inclusive, while held by dwell 38A against oscillation, after which the needle bar is swung by the cam projection 39 in the direction opposite to normal feed of the work and penetrates and withdraws from the work to form the last superposed stitch 27F as shownin Figures 36 to 38 while held by dwell 99A against oscillation. Then operation of the work feed mechanism is resumed, the cam surfaces 30 and 3! and their dwells 99A and MA being successively brought into engagement with the roller l0 and the cam surfaces 340 and dwells 3 being successively brought into engagement with' the roller 29 so as to form a series of running stitches 29.

It is necessary that the needle bar be returned from the position shown in Figure 38 to its initial or neutral position shown in Figure 20 by the time the work has reached the point for formation of the next series of superposed stitches. For this purpose the needle oscillating cam BB has the cam projections 340 progressively eccentric to the axis of rotation of the cam so as to move the needle bar step-by-step synchronously with the movement of the work feed mechanism in the direction of work feed, each step of a length corresponding to the distance of movement of the needle bar in the direction of movement of'the work during the formation of the second superposed stitch, i. e. the length of one step of movement of the work feed mechanism, divided by the number of running stitches 29 between the series of superposed stitches.

The various steps in the formation of the stitches and the nature of the stitches is also illustratedin Figure 1'7, the formation of the first three superposed stitches while the work is stationary and the needle is oscillated being shown at l'IA-|'IC, the formation of the skip stitch while the work is advanced and the needle is moved in the direction opposite to movement of the work being shown at D, the formation of the next superposed stitches being shown at |7C-l'IG and the beginning of formation of the running stitches with the work advancing being shown at "H and "I. 1

Itwill beobserved from the foregoing that reciprocation and back and forth movement of the needle and movement of the work feed mechanism are correlated and operate in corresponding cycles to form during each cycle a series of running stitches 29, in the present instance 76 stitches, followed by a series of three superposedstitches 27 followed by a jump stitch 28 which is in turn followed by another series of three superposed stitches 21. The cam surfaces and,

dwells of the two cams AA and BB are of such size and so related to each other and to the needle reciprocating mechanism that the work is fed step-by-step, the needle penetrates and withdraws the work while the work is stationary between its steps of movement, and the needle is oscillated while it is out of the work.

A modification of the invention is shown in Figures 14, 16 and to '79 inclusive whereby the return of the needle bar to its neutral position after the formation of the superposed stitches as above described is obviated. In this form of .the invention the needle bar oscillates between two limits and assumes only two difierent positions; and the needle is always located the same distance at one side or the other of the central point between the two limits of movement.

The work feed cam and needle oscillating cam for this form of the invention are shown in Figures 16 and 14 respectively. The work feed cam CC has a series of cam. surfaces-l0 and 4| and corresponding dwells 40A and A for forming the running stitches, while the needle actu- VIII is in engagement with the dwell 46 ofthe cam CC and on continued movement of the cams, the roller 20 rides over the cam surface 47 to move the needle one step in the direction of movement of the work as shown in Figure 61, after which the roller 20 rides on the, dwell 48. The needle then penetrates and withdraws from the work as shown in Figures 62 and 63 and the work feed follower roller I0 is engaged by a cam surface 49 which moves the work one step as shown in Figure 64. While the roller is on the dwell 50 the needle penetrates and withdraws from the work as shown in Figures and 66 to form the third superposed stitch. Thereupon the work feed roller I0 is engaged successively by the cam surfaces 5| and 52 to move the work two steps forwardly, and the needle oscillating roller 20 is engaged by the cam surface 53 to swing the needle one step in the direction opposite to that of movement of the work as shown in Figure 67. The roller III is then on the dwell 54 and the roller 20 is on the dwell 55, and the needle penetrates and withdraws from the work as shown in Figures 68 and 69 to form the skip stitch. The needle bar is still held against oscillation by the dwell 55 while the work is advanced one step by the cam surface 58. While the roller I0 is on the dwell 59 the needle penetrates and withdraws from the work as shown in Figures '71 and '72 to form the first superposed stitch. The needle is then swung in the direction of movement of the work one step by the cam surface 56, as shown in Figure '73, and the needle penetrates and withdraws from. the work to form the second superposed stitch as shown in Figures '74 and-75. Thereupon the work is moved one step in advance by the cam surface GI and simultaneously the needle is swung one step in the direction opposite to that of movement of the work by the cam surface 62 as shown in Figure '76. The needle then penetrates and withdraws from the work to form the third superposed stitch. It will be observed that the needle is now in its initial position as shown in Figure 60 and ready to begin the formation of the next series of running stitches, the roller 26 being on the concentric dwell 42 of cam DD and the roller I0 engaging the cam surfaces 40 and 4| to move the work step-by-step to form the running stitches, the first of which is shown in Figure '79.

In Figure 19 the formation and nature of the stitches as above described 'is schematically illus-- trated, the formation of the first superposed stitch before the jump stitch being shown at 79A and the formation of the second secondary stitch being shown at 19B, both while the work is sta-- movement of the work or two in the work is fed continuously step by step by the usual work feeding mechanism of the sewing machine. The stitch forming mechanism is the same as that hereinbefore described and the mechanism including the feed dog and the parts R, S, T and U for moving it toward and from the work, are the same as hereinbefore described. The feed dog is reciprocated back and forth by the usual "mechanism including the shaft EE which corresponds to the shaft X above described and which is oscillated by the usual crank and pitman connection FF from the drive shaft I of the machine, instead of by the slide 4' and pin 1 of the form of the machine shown in Figures 1 and 3. The link R which carries the feed dog is pivotally connected to an arm GG on the shaft EE just as said link R is connected to the crank W on the shaft X.

The cam for oscillating the needle is designated HI-l'and is shown in detail in Figures 11 and 12. The cam includes a series of cam surfaces 65 and corresponding dwells 66 which are similar to the cam surfaces and dwells 340 and 34! above described, for forming the running stitches. In this form of the invention the needle is mounted to swing a distance equal to the length of two steps of movement of the work feed mechanism, and at the end of the first superposed stitch before the jump stitch, the needle is in its foremost position toward the front of the machine as shown in Figure 40. Inthis position the follower roller 26 is about to be engaged by the cam surface t'l upon rotation ofthe cam HH in the direction of the arrow, and as the roller rides over this cam surface, the needle is swung two steps in the direction of movement of the work as shownin Figure 41. It will be remembered that the work is continuously moving and will have moved one step simultaneously with the above mentioned movement of the needle, so that the needle will be in position to penetrate the work atthe beginning of the first superposed stitch as shown in Figure 41. The roller 26 will then ride over the dwell 68 while the needle penetrates and withdraws from the work to form the second superposed stitch as shown in Figures 42 and 43. The work will then move another step, whereupon the needle will again penetrate and withdraw from the work to form the third superposed stitch as shown in'Figures 45 and 46. Thereupon the roller 20 will ride over the cam surface it whereby the needle will be swung in a direction opposite to that of movement of the work a distance equal to two steps of movement of the work or two stitches, and simultaneously the work will move forwardly one step, as shown in Figure 47. Thereupon the roller 20 will engage the dwell H and the needle will penetrate and withdraw from the work as shown in Figures 48 and 49 so as to form a jump stitch equal in length to three normal stitches. The roller 20 will continue on the dwell ll while the work goes forwardly another step as shown in Figure 50, whereupon the needle will penetrate and withdraw from the work to form the first superposed stitch at the end of the jump stitch as shown in Figures 51 and 52. Then the roller 20 will ride over the cam surface 12 so- 1 that the needle is swung in the direction of movement of the work a distance equal to two steps of stitches, and the work will move forward one step as shown in Figure 53. The needle will then pene- 'trate and withdraw from the work to form the.

second superposed stitch as shown in Figures 54 ment of the roller with the cam surface 65 and I dwells 66 to complete the series of running stitches.

It is necessary, by the time the first superposed stitch of the next series is to be formed, thatthe needle be returned to its initial position shown in Figure 40, and accordingly the cam surfaces 65 and dwells 65 are progressively eccentric to the axis of rotation of the cam HH in a manner similar to that of the cam surfaces 340 and 3 of the cam BB. Accordingly the needle will be moved in the direction opposite to that of movement of the work in equal steps each of a length equal to the distance of movement of the needle from one limit of oscillation to the other, divided by the number of running stitches between the series of superposed stitches. i

In Figure 18 is shown schematically the formation and nature of the stitches, the formation of the first superposed stitch corresponding to Figure 40 being shown at IBA, the formation of the second and, third superposed stitches preceding the jump stitch being shown at MB and MC,

and the formation of the jump stitch being shown at MD. The formation of the next series of superposed stitches is shown at l8E to [8G inclusive, while the formation of the first two running stitches after the superposed stitches at the end of the jump stitch is shown at "SH and I81.

It will be understood by those skilled in the art that the number of superposed stitches may be varied and the length of the jump stitches may also be varied, and the number of running stitches may be varied, by simply modifying the number and shape of the various cam surfaces and dwells of the cams and changing the timed relation of the oscillation of the needle bar, the movement of the work feed mechanism and the reciprocation of the needle. As will be apparent from the foregoing, by varying the shapes and relation of the cam surfaces and the cam dwells, the length of running stitches can be increased or decreased automatically, and continuously if desired, by back and forth movement of the needle and without change in the work feed. Also, should it be desired to make more superposed stitches than is possible with the range of oscillation of the needle, the mechanism might be modified to stop feed of the work momentarily and produce more oscillations of the needle.

Where it is impractical to use the feed dog work feed mechanism above described, for example in stitching snap fasteners on tape, I may use feed rollers such as shown in my Patent No. 2,052,896 for feeding the work.

The use of the back and forth movement of the needle to vary the length of the stitches or form superposed stitches ensures extremely accurate and rapid stitching, as compared with use i of the work feed mechanism for reversing or varying the feed of the work where time is lost by manipulation of the feed mechanism and accuracy is affected by lost motion between the many parts and between the feed dog and the work.

It is highly desirable, especially in making fastener tape, that the jump stitches and superposed stitches be accurately spaced, and the usual feed dog work feed mechanism above described sometimes permits relative slipping of the work and the work feed dog and between which the work to be operated upon is gripped, one roller being mounted in the frame of the machine ona shaft 83 and the other mounted on a shaft 84 in a frame 85 pivoted at 86 so that the roller 8| may be influenced toward the roller 80 by a spring 81. The rollers are geared together to rotate at the same peripheral speeds by meshing pinions 82, one on each of the rollershafts 83 and 84, and one of the shafts, in the present instance the shaft 83, is driven by a helical gear connection 88 with a jack shaft 89 which has a helical gear connection 90 with the counter-shaft 22. The rollers 8|] and 8| more firmly grip the work than do the presser foot and feed dog, and feed the work accurately in timed relation to the stitch form-' ing mechanism. The feed dog is normally adjusted to feed a length of work slightly greater than the length supplied by the feed rollers for each stitch to ensure that the full amount of work shall be brought to. the needle, and the pressure of the feed dog on the work is such that it may slip beneath the work afteryit has fed the exact amount controlled by the feed rollers. With this construction, the work is positively gripped between the

feed rollers

80 and 8| and the rollers are constantly rotated at a uniform speed in timed relation to the drive shaft and the needle, so that the work may be fed with accuracy and the jump stitches 28 may be accurately spaced in the work and over-feed of the work is prevented. Under feed also is prevented by the adjustment of the dog feed to feed more than desired and the preventing of excess

feed by'the rollers

80, 8| which hold back the work to the feed desired, the dog slipping slightly over the work to compensate therefor. 1

Where it is desired that 'two sets of stitches shall be made and exactly spaced to enter apertures in an object on the'work, or shall be made with one tightly against each of opposite/sides of an object on the work, for example ..a fastener element, as shown respectively in my dependin application's Serial No. 92,711, filed July-27, 1 and Serial No. 106,326, filed October 19, 1936, the present invention utilizing two needles is especially useful, because the needles can be accurately spaced one at each side of the fastener element and the two sets of stitches can be formed automatically and simultaneously. Should the two sets of stitches be made at different times with a single needle, the time required would be at least doubled, and it would be practically impossible to cause the stitches to tightly hug opposite sides of the fastener elements in an automatic operation, and without stopping of the machine and possible manual manipulation of the work, because or possibility of movement of the fastener element between the operations or change in relation of the work to the needle dur-. ing the formation of the second set of stitches.

Other modifications in the method and structure of the machine will occur to those skilled in tliie art as within the spirit and scope of the invent on.

Having thus described my inventiomwhat I claim is:-

1. In a sewing machine, the combination of work feed mechanism, stitch forming mechanism including a reciprocatory needle that is also movable back and forth in a plane parallel with the direction of movement of the work, automatic means for moving the work feed mechanism continuously in one direction step-by-step with one step for each reciprocation of the needle, means for continuously reciprocating the needle in timed relation to step-by-step movement of the work feed mechanism to form running stitches, and automatic means operative during reciprocation of the needlefor moving said needle back and forth while it is out of the work and to suecessively move the needle in the direction of movement of the work simultaneously with a step of movement of the work a distance equal to a multiple of the length of said step of movementof the work and hold the needle against back or forth movement during the next step of movement of the work, to form a series of superposed stitches.

2. In a sewing machine, the combination of work feed mechanism, stitch forming mechanism including a reciprocatory needle that is also movable back and forth in a plane parallel with the direction of movement of the work, .automatic means for moving the work feed mechanism continuously in one direction step-by-step with one step for each reciprocation .of the needle, means for continuously reciprocating the needle in timed relation to step-by-step movement of the work feed mechanism to form running stitches, and automatic means operative during reciprocation of the needle for moving said needle while it is out of the work and in the direction opposite to movement of the work simultaneously with a step of movement of the work.

3. In a sewing machine, the combination of work feed mechanism, stitch forming mechanism including a reciprocating needle that is also movable back and forth in a plane parallel to the direction of movement of the work, automatic means for controlling the work feed mechanism in cycles in timed relation to reciprocation of said needle' to form a stitch upon each reciprocation of the needle, and automatic means operative during reciprocation of the needle for moving said needle back and forth while it is out of the work at different intervals and diflerent distances in each cycle of movement of the work feed mechanism and in timed relation .to reciprocation of the needle.

4. In a sewing machine, the combination of work feed mechanism for feeding work step-bystep, stitch forming mechanism including a needle that is reciprocable and is also movable in a plane parallel to the direction of movement of the work, means for reciprocating said needle. to form a stitch of given length upon each step of movement of the work, and automatic means operative during reciprocation of the needle for moving said needle in said plane'while the needle is out of thework and in steps synchronous with the movement of the work andeach of a length less than the corresponding step of movement of the work to vary the lengths of the stitches.