US3137256A

US3137256A - Buttonhole sewing mechanism in zigzag sewing machines

Info

Publication number: US3137256A
Application number: US134357A
Authority: US
Inventors: Fujita Toshio
Original assignee: SANWA MISHIN SEIZO KABUSHIKI K
Current assignee: SANWA MISHIN SEIZO KABUSHIKI K; SANWA MISHIN SEIZO KK
Priority date: 1961-08-28
Filing date: 1961-08-28
Publication date: 1964-06-16
Anticipated expiration: 1981-06-16

Description

June 16, I964 TOSHIO FUJlTA 3,137,256

BUTTONHOLE SEWING MECHANISM IN ZIGZAG SEWING MACHINES Fiful.

INVENTOR.

June 16, 1964 Tosl-no FUJITA 3,137,256

BUTTONHOLE SEWING MECHANISM IN ZIGZAG szwmc MACHINES Filed Aug. 28, 1961 2 Sheets-Sheet 2 INVENTOR.

. 3,137,256 BUTTONHOLE SEWING MECHANISM IN ZIGZAG SEWING MACHINES Toshio Fujita, Morigu chi, Osaka-Eu, Japan, assignor to Sanwa Mishin Seizo Kabushiki Kaisha (Sanwa Sewing Machine Mfg. Co., Ltd.), Kawachi, Osaka-tn, Japan. Filed Aug. 28, 1961, Ser. No. 134,357 4 Claims. (Cl. 112-158) United States Patent 3,137,256 Patented June 16, 1964 cam or cam unit for adjusting the amplitude of the swinging movement of the needle to produce ornamental seams.

FIGURE 8 represents diagrammatically a seam line formed on the left-hand side of a buttonhole. 7

FIGURE 9 represents diagrammatically a seam line formed on the right-hand side of the buttonhole.

All of the drawings illustrate only those elements and devices which are essential to my improved mechanism and other component elements of a zigzag sewing machine not related to the present mechanism are omitted from in conventional zigzag sewing machines and, similarly,

buttonhole, from the outer line of a zigzag seam on one side of the buttonhole to the outer line of a zigzag seam on the opposite side of the buttonhole automatically, connecting the upper and lower ends of seam lines on both sides of the buttonhole rigidly and reasonably by means of the so-called barring stitches.

Another object of this invention is to provide a unique buttonhole sewing mechanism so devised that barring stitches at the upper and lower ends of t a buttonhole are effected in odd numbers, whereby the needle is made to return to its initial position upon completing thelast stitch in a buttonhole sewing operation, so that the same operation may be repeated over and over again.

In order to permit zigzag sewing machines to perform the aforesaid buttonhole sewing operation incorporating the formation of perfect barring stitches in odd numbers at the upper and lower ends of a buttonhole, a unique cam member for formingbarring stitches (hereinafter referred to as a barring-stitch forming cam) the periphery of which comprises a raised portion to swing cam follower means outwardly for each half rotation of the barring-stitch forming cam, a recessed portion to swing the said cam follower inwardly for each half rotation of the cam and several protrusions and recessions provided at the edges of the raised and lower portions to swing the said cam follower odd times, is provided. The said barring-stitch forming cam is mounted loosely on a cam shaft driven by a main shaft and is operably connected by a clutch member with a master cam mounted on the same cam shaft'to transmit the various motions'of the master cam and the barring-stitch forming cam, either singly or in combination, to the needle bar.

In order that the mechanism of my invention may be clearly understood, I shall now describe in detail the nature of my invention with reference to the accompanying drawings, forming a part of the present application and illustrating the new devices and arrangements. In the drawings:

FIGURE 1 represents a front elevation, partly in sec.- tion, of a zigzag sewing machine incorporating my improved mechanism for buttonhole sewing.

FIGURE 2 represents a plan view of the component elements of ,my improved mechanism shown in FIG. 1. FIGURE 3 represents a sectional view of the mechanism, as taken on the section line III--III of FIG. 1.

. FIGURE 4 represents a sectional view of the; same mechanism, as taken on the section line IV--IV of FIG. 1.

FIGURE 5 represents a sectional view of the same mechanism, as taken on the section line VV of FIG. 1.

FIGURE 6 represents a perspective View of a new device for barring-stitch formation.

FIGURE 7 represents a perspective view of a part of a regulator 32.

the drawings. The same reference characters refer to the same parts throughout the drawings. I

The bracket-arm 1, hollow standard 2 and bed plate 3 are of the same shapes and constructions as those used other component elements mounted inside thoseparts, such as a main shaft 4, a needle bar 5, a presser bar 6, a means for moving a shuttle in time with the zigzag movement of the needle bar, are the same as for conventional zigzag sewing machines.

Now, mounted on a cam shaft 9 which is driven by the main shaft 4 by means of engagement of a worm 7 of the main shaft with a worm wheel 8 of the cam shaft 9 are three cams of diiferent shapes and types, namely, a barring-stitch forming cam 10, a cam unit 17 for adjusting the amplitude of the swinging movement of the needle to produce ornamental seams (hereinafter simply referred to as a pattern cam) and a master cam 19. The barringstitch forming cam 10, the periphery of which comprising, as described hereinbefore, a raisedportion 14, a recessed portion 15,

protrusion

14, 15 and recessions 14", 15" provided at the starting edge of each of the raised and lower portions in respect of the direction of rotation of the cam 10, is mounted loosely on the cam shaft 9,

Provided adjacent the periphery of the said barringstitch forming cam 10 is a cam follower means 13 having substantially the shape of the letter U in a side view, with its base portion pivotally secured to a shaft 12 so as to permit its two

spaced ends

13 and 13" to pivot on the shaft 12.. The said U-shaped cam follower 13 carries at its upper end 13' a follower pinll for constant engagement with'the periphery of the cam 10, whereby the follower pin 11 on the upper end 13' is, upon rotation of the cam 10, swung outwardly or inwardly as dictated by the periphery of the cam 10, hence causing the other upper end 13 to swing in the same way.

Since the upper end 13" of the U-shaped cam follower 13 is linked to aIregulator 32by means of a connecting rod 29, a bell-crank lever .30and a connecting rod 31, the swinging motion of the upper end 13" causes the regulator 32 to swing upwardly against the force of a coil spring 33 having its one end secured to a part of the machine frame and its other end secured to a part of the In this case, the amplitude of swinging motion of the regulator 32is greater than that of swinging motion of the upper end 13, because the distance from the upper end 13" to its pivot shaft 12 is greater than that from the follower pin 11 to the shaft 12.

The said movement of the regulator 32 changes the angle of inclination of a groove 34 provided thereon, whereby a protuberance 35 carried by a bifurcated connecting rod 36 and slidably accommodated in the groove 34 changes the direction of its sliding movement, imparting a swinging motion to the bifurcated connecting rod 36 which is disposed to swing about the protuberance 35 as its fulcrum. The movement of the rod 36 is then transmitted to a horizontally-disposed feeding shaft connected therewith for automatic reversal of the direction of feeding.

The regulator 32 carries at its lower portion a protuberance 39 projecting downwardly for engagement in a limiting groove 41 provided on a regulator-control cylinder 48 rotatably supported in the machine frame. The said limiting groove 41 extends radially from the centre of the cylinder 40, and by turning the regulator-control cylinder 40 through the manipulation of a dial 42 fixed thereto externally of the machine frame, the limiting groove 41 on the control cylinder 40 is rotated to set the angle of inclination of the regulator 32 at any desired degree to provide the desired volume of feeding. Since, however, the mechanism for adjusting the volume of feeding is the known art and the same mechanism does not constitute an essential element in the present invention, a detailed explanation of this mechanism is omitted.

Provided adjacent the upper end 13" of the cam follower is an oscillator member 45 having its base end pivotally secured to a bracket 43 by means of a pintle 44 and carrying at its upper end a pin 46 for engagement with one side of the upper end 13 of the cam follower 13, and engaging one side of the oscillator member 45 is an elongated pin. 47 carried on a movable arm means 24) for shifting the center-line of scam, which arm means 20 being pivotally secured at its base end to a bracket by means of a pintle 21. It will thus be known that the swinging motion of the cam follower 13 is transmitted not only to the feeding mechanism, as described before, but also to the center-line shifting mechanism through the oscillator member 45, the elongated pin 47 and the movable arm means 20 in the order given.

Adjacent the periphery of the barring-stitch forming cam and opposite the location of the cam follower 13 is provided a finger-shaped switch means 48 pivota1ly mounted at its approximate midpoint on a shaft 49 and having its base end operably connected with a control lever 50 through a connecting rod 51. Since the control lever 50 is connected with a push-button means 52 through suitable connecting members, when the edges of the pushbutton 52 are pushed in alternatively, the control lever 51) is swung laterally, causing the switch means 48 to swing reciprocatingly on its fulcrum shaft 49.

The finger-shaped switch means 48 carries at its upper end a hooked member 53 and at its lower end a hooked member 53', both of which extend inwardly to face each other, and on the other hand, the barring-stitch forming cam 10 carries on one side thereof a clutch finger 16. The two inwardly extending

hooks

53 and 53 are so arranged that, when the switch means 48 is swung reciprocatingly on its fulcrum shaft 4-9, they move into or out of the path of the clutch finger 16 alternatively.

The switch means 48 also carries at its lower portion a pin 54 for engagement with the upper end of a T-shaped switch-control member 56 having its base end pivotally secured to a part of the machine frame and having its lower end 57 constituting a follower for engagement with the periphery of a disk 59 rigidly mounted on a shaft 58. When the disk is rotated by turning a handle 60 fixed to the outer end of the shaft 58, a cut-out portion 61 on the periphery of the disk 59 is moved into engagement with the lower end 57 and then with further rotation of the disk 59, it is moved to disengage from the lower end 57, imparting thus a swinging motion to the T-shaped control member 56 to control the movement of the switch means 48.

Rigidly secured on the cam shaft 9 is the pattern cam 17 having on one side thereof a clutch groove 18 into which the clutch finger. 16 carried on the barring-stitch forming cam 10 engages periodically, and also secured rigidly on the cam shaft 9 adjacent the other side of the pattern cam 17 is the master cam 19. Provided adjacent the said center-line shifting arm means 20 is another oscillator piece 22 having its upper end portion pivotally secured to the movable arm means 20 at 23 and carrying at its lower end a follower pin 24 for constant engagement with the periphery of the master cam 19. Under the above arrangement, when the master cam 19 rotates, the oscillator piece 22 pivots on its fulcrum point 23, imparting a 4. reciprocating motion to a rod 26 engaging a protuberance 25 carried on the oscillator piece 22. The reciprocating motion of the rod 26 is then transmitted by a crank lever 27 to an L-shaped lever 28 pivotally secured at its approximate midpoint 37 to a a part of the machine frame, whereupon the needle bar 5 supported in the L-shaped lever 28 is caused to oscillate transversely to perform zigzag sewing.

Now, regarding the position of the present improved mechanism before the start of a button hole sewing operation, the lower end 57 of the T-shaped control member 56 has been running on the periphery of the disk 59, with the upper end of the control member 56 pressing the pin 54 of the finger-shaped switch means 48 upwardly to hold the switch means 48 in non-operative position.

Before starting a button hole sewing operation, the disk 59 is rotated by turning the handle 60 fixed to the outer end of the shaft 58, until the cut-out 61 of the periphery of the disk 59 is moved to a position coincident with the location of the lower end 57 of the control member 56, whereupon the lower end 57 falls into the cut-out 61, disengaging the upper end of the control member 56 from the pin 54 of the switch means 48 whereby the machine is converted from conventional sewing to button hole sewmg.

With the switch means 48 shifted to its operative posirion for sewing button holes, the machine is set in motion. The 1st stitch of a buttonhole sewing is effected, as shown in FIGURE 8, at the uppermost end of the outer line of a zigzag seam on the left-hand side of a buttonhole (a), the 2nd stitch on the inner line, the 3rd stitch on the outer line again and so on, as led by a conventional zigzag motion, until a zigzag sewing on the lefthand side of the button hole is completed.

During the above sewingoperation, both the pattern cam 17 and the master cam- 19 rigidly mounted on the common cam shaft 9 rotates with rotation of the latter, causing the oscillator piece 22 to swing reciprocatingly on its fulcrum point 23, which reciprocating motion of the oscillator piece 22 being then transmitted, by the rod 26 connected thereto, the crank lever 27 and the L-shaped lever 28, to the needle'bar 5 to oscillate the latter transversely for formation of a zigzag seam on the lefthand side of the buttonhole (a).

On the other hand, since thebarring-stitch forming cam 10 is loosely mounted on the cam shaft 9, the cam 10 does not rotate with rotationof the cam shaft 9 and is held in the standstill position, and also during the above sewing operation, the lower hooked member 53' carried on the finger-shaped switch means 48 remains in the path of the clutch finger 16 to press and keep the latter away from engagement with the recessed clutch means 18 provided on the pattern cam 17.

The moment a zigzag sewing on the left-hand side of the buttonhole has been completed, the pushbutton 52 is pushed in to swing the control lever 50 to the opposite direction, which movement of the lever 50 is transmitted by the connecting rod 51 to the switch means 48, causing it to swing, whereupon the lower hooked member 53' is moved outwardly, disengaging itself from the clutch finger 16. At this moment, as the clutch finger 16 on the switch means 48 engages in the recessed clutch means 18 of the pattern cam 17, the barring-stitch forming cam 10 and the'pattern cam 17 are connected with each other to constitute a single functional unit, which then rotates with rotation of the cam shaft 9.

Now, with rotation of the barring-stitch forming cam 10, thefollower pin 11 of the cam follower 13, which has been held in contact with the terminal edge of the recessed portion 15 of the periphery of the cam 10, starts moving toward the raised portion 14, and when the follower pin 11 has moved up on the protrusion 14' established hi. front of the raised portion 14 in relation to the direction of rotation of the cam 10, the cam follower 13 is swung outwardly, causin the movable arm means 20 and the oscillator member 45 to swing outwardly. This movement of the

members

20 and 45 actuates the outward movement of the point 23 at which the oscillator piece 22 is pivotally secured to the movable arm means 20, thereby moving the needle bar 5 outwardly to shift the neutral point of its zigzag movement to the inner line of a zigzag seam on the opposite side, namely, on the right-hand side of thebuttonhole (a). At this moment, another oscillating motion is imparted to the needle bar 5 by the master cam 19 through the oscillator piece 22, and this motion is synchronized with the motion actuated by the movable arm means 20 by engagement of the clutch element 16 with recess 18 as described above and shifts the neutral point of the needle bar 5 by the distance corresponding to the combined amplitude of the two motions, thereby shifting the needle to the outer line of a zigzag seam on the right-hand side of the buttonhole to effect the 1st stitch on the right-hand side at that position.

At the next moment, the follower pin 11 carried on the cam follower 13 falls into the recession 14", causing the cam following 13 to swing inwardly to take its original position and simultaneously, the follower pin 24 carried on the oscillator piece 22 falls into the bottom of the master cam 19, thereby shifting the neutral point of the needle bar back to its initial position, namely, to the outer line of a zigzag seam on the left-hand side of the buttonhole (a), where the 2nd stitch is effected. This operation is repeated odd times as dictated by the protrusions 14' and the recessions 14", so that barring stitches (b) in odd numbers may be produced at the lower end of the buttonhole (a).

With further rotation of the barring-stitch forming cam 10, the follower pin carried on the cam follower 13 moves up on the raised portion 14, causing the upper end 13" to swing outwardly, and while the follower pin llruns on the raised portion 14, the upper end 13" is held in that position, pulling upwardly the regulator 32 connected thereto through the linking

members

29, 30 and 31 for automatic reversal of the feeding direction. With the direction of feeding shifted backward, zigzag sewing of the right-hand side of the buttonhole (a) is effected under a conventional zigzag motion actuated by the coordinated motions of the master cam 19 and the oscillator piece 22;

During the above sewing operation, the barring-stitch forming cam and the clutch finger 16 carried thereon rotate, and as the clutch finger 16 passes under the upper hooked member 53 which has remained in the path of the clutch finger 16 since the time when the oppositelydisposed hooked member 53' was moved out of the path of the clutch finger 16 by means of the switch means 48, the upper hooked member 53 presses the clutch finger 16 to disengage the latter from the recessed clutch means 18 of the pattern cam 17, thereby releasing the barringstitch forming cam 10 from engagement with the pattern cam 17 and the master cam 19. At this moment, the cam 10 suspends its rotation with the follower pin 11 of the cam follower 13 positioned at the terminal edge of the raised portion 14 of the cam periphery. Under such arrangement, zigzag sewing of the right-hand side of the buttonhole is continued by only a conventional zigzag motion.

The moment the zigzag sewing has been completed, the control lever is swung back to its initial position by means of pressing the push-button 52, thereby causing the switch means 48 to swing back to its original position, whereupon the upper hooked member 53 is moved out of engagement with the clutch finger 16 to permit the latter to engage in the recessed clutch means 18 again, thus connecting the barring-stitch forming cam, the master cam and the pattern cam together for a synchronized rotation on the common shaft 9.

Then, with rotation of the barring-stitch cam 10, the

follower pin 11 which has been held in the standstill position at the terminal edge of the raised portion 14 starts moving toward the recessed portion 15 and when it falls into the recession 15" provided in the front of the recessed portion 15 in relation to the direction of rotation of the cam 10, all of the cam follower 13, the movable arm means 20 and the pivotal point 23 of the oscillator piece 22 are moved inwardly, causing the neutral point of the zigzag movement of the needle bar 5 to shift to the inner line of zigzag seam on the left-hand side of the buttonhole (a). At this moment, as already described inthe case of shifting of the needle bar from the lefthand side to the right-hand side of the buttonhole (a), the needle bar is shifted to the outer line of zigzag seam on the left-hand side of the buttonhole by the added movement of the synchronized motions of the barringstitch forming cam 10 and the oscillator piece 22, where it effects a barring stitch.

At the next moment, the follower pin 11 rises up on the protrusion 15', moving the cam follower 13 outwardly, and simultaneously, the follower pin 24 carried on the oscillator piece 22 rises up the top of the master cam 19. With the added movement of the synchronised motions, the needle bar 5 is shifted back to the outer line of zigzag seam on the right-hand side of the buttonhole to effect another barring stitch. This operation is repeated odd times to effect barring stitches in odd numhere at the upper end of the buttonhole, thus completing the whole buttonhole sewing operation.

At this moment, as the follower pin 11 on the cam follower 13 engages the recessed portion 15 of the periphery of the barring-stitch forming cam 10, biasing the follower 13 inwardly, the feed adjusting mechanism connected thereto through the linking

members

29, 30 and 31 is shifted back to its forward-feeding position to prepare for the next buttonhole sewing operation, with the neutral point of the needle bar positioned at the uppermost end of the outer line of a zigzag seam on the left-hand side of the next buttonhole.

In the barring-stitch operation wherein the cam follower 13 is swung odd times by the protrusions 14 and 15' and recessions 14" and 15", the outward movement of the cam follower 13 causes the feed-adjusting mechanism connected therewith through'linking members to shift from the forward position to the backward position and vice versa, but since the switch-overs of feed directions take place almost instantaneously with the fol lower pin 11 rising up and falling down the protrusions and recessions almost instantaneously, the cloth moves only slightly. For the formation of ordinary zigzag seams after the completion of the buttonhole sewing operation, the disk 59 is rotated by turning the handle 60, whereupon the lower end 57 of the T-shaped control member 56, which has been engaged in the cut-out 61 of the disk 59, is caused to run up on the periphery of the disk member, resulting in the upper end of the control member 56 pressing the pin 54 of the switch means 48 upwardly. Then, the lower hooked member 53' of the switch member 48 is caused to press the clutch finger 16 to disengage the latter from the recessed clutch means 13 of the pattern cam 17, thereby releasing the barrings'titch forming cam 10 from engagement with the cam shaft 9 and holding the cam 10 in its non-operative position during the formation of ordinary zigzag seams.

As hereinbefore described, by providing conventional zigzag sewing machines with my improved mechanism, the machines are made to perform not only zigzag sewing of various patterns but also buttonhole sewing wherein zigzag sewing of both sides of a buttonhole is effected under a conventional zigzag motion and barring stitching of the upper and lower ends of the buttonhole is effected under the coordinated motions of the master cam and the barring-stitch forming cam.

Furthermore, since a switch-over from a conventional zigzag motion to a barring-stitch motion and vice versa can be carried out by simply pushing a pushbutton, a buttonhole sewing operation incorporating perfect barring stitches in odd numbers will be accomplished with great ease and, further, such a switch-over can be carried out at any time and place desired, permitting sewing of butto'nholes of various lengths.

Having thus described the nature of my invention, what I claim herein is:

1. In a zigzag sewing machine having a transversely oscillatable needle bar, a buttonhole sewing mechanism comprising a main shaft, a cam shaft driven by the main shaft, a master cam and a pattern cam rigidly mounted on the cam shaft, a cam for barring stitching having a periphery mounted loosely on said cam shaft at a position adjacent said pattern earn, a cam follower member, the periphery of said barring-stitch forming cam comprising a raised portion to swing said cam follower member engaging therewith outwardly for a substantial portion of a half rotation of said earn, a recessed portion to swing said cam follower member inwardly for a similar portion of a half rotation of said cam, protrusions and recessions provided at the starting edge of each of said raised and recessed portions to swing said cam follower an odd number of times, a fingered clutch means mounted on one side of said barring-stitch forming cam to selectively connect the latter for rotation with said cam shaft, and manually operated means to actuate said clutch means.

2. In a zigzag sewing machine having a transversely oscillatable needle bar, a buttonhole sewing mechanism comprising a main shaft, a feed adjusting mechanism for said sewing machine, a cam shaft driven by the main shaft, a master cam and a pattern cam rigidly mounted on said cam shaft, a cam for barringstitching mounted loosely on said cam shaft at a position adjacent said pattern cam, manually operated means adapted to selectively connect said cam for barring stitching to said cam shaft, a cam follower member provided adjacent said barring-stitch forming cam, said cam follower member being constructed in the shape of the letter U in side view, and having its base portion pivotally secured to a shaft, a connecting rod connecting one upper end of said U with said feed-adjusting mechanism, a bell-crank lever and other linking members, a follower pin carried on the other upper end of the U-shaped cam follower for constant engagement with the periphery .of said barring-stitch forming cam, an oscillator member provided adjacent said cam follower, a bracket mounted in said sewing machine, said oscillator member having its base end pivotally secured to said bracket and a pin mounted at the upper end of said bracket for engagement with one side of said cam follower, a movable arm means for shifting the center line of a seam adapted for engagement with the upper side of said oscillator member, an elongated pin carried on the upper portion thereof, said movable arm means having its base end pivotally mounted on said machine, another oscillator piece pivotally secured at its upper end to the upper portion of said movable arm means and a protuberance on one side of said another oscillator piece, a connecting rod means connected to said another oscillator piece by said protuberance, said connecting rod means being linked at its end to the needle bar through a plurality of suitable linking members.

3. In a zigzag sewing machine having a transversely oscillatable needle bar, a buttonhole sewing mechanism comprising a main shaft, a cam shaft driven by the main shaft, a master cam and a pattern cam rigidly mounted on said cam shaft, a cam for barring stitching mounted loosely on said cam shaft, a fingered clutch means adapted to secure said cam for barring stitching to said cam shaft, a switch means provided opposite the periphcry of said barring-stitch forming cam and pivotally mounted at its approximate midpoint, said switch means carrying at both its ends a hooked member arranged to be moved selectively into and out of the path of said fingered clutch means and a control lever operatively connected to said switch means. I

4. In a zigzag sewing machine having a shaft, a disc, a transversely oscillatable needle bar, a buttonhole sewing mechanism comprising a main shaft, a cam shaft driven by the main shaft, a master cam and a pattern cam rigidly mounted on said cam shaft, a cam for barring stitching mounted loosely on said cam shaft at a position adjacent said pattern cam, clutch means on said cam for barring stitching adapted to engage said pattern cam, a switch means for disengaging said clutch means provided opposite the periphery of said barring-stitch forming cam having fingers extending between said pattern cam and said cam for barring stitching said switch means being pivotally mounted at its approximate midpoint, a T-shaped control means, a pin carried on said switch means for engagement with the upper end of said T-shaped control means, said control means pivotally secured to the machine a notched, manually rotatable disc mounted on said machine, and follower means operatively connected to said T-shaped control means whereby, when said disc is rotated to bring said notch opposite said follower, said control means is withdrawn from said switch means.

References Cited in the file of this patent UNITED STATES PATENTS 1,675,508 Muller July 3, 1928 2,901,068 Tipper Aug. 25, 1959 2,983,240 Engel May 9, 1961 3,060,875 Iida Oct. 30, 1962

Claims

1. IN A ZIGZAG SEWING MACHINE HAVING A TRANSVERSELY OSCILLATABLE NEEDLE BAR, A BUTTONHOLE SEWING MECHANISM COMPRISING A MAIN SHAFT, A CAM SHAFT DRIVEN BY THE MAIN SHAFT, A MASTER CAM AND A PATTERN CAM RIGIDLY MOUNTED ON THE CAM SHAFT, A CAM FOR BARRING STITCHING HAVING A PERIPHERY MOUNTED LOOSELY ON SAID CAM SHAFT AT A POSITION ADJACENT SAID PATTERN CAM, A CAM FOLLOWER MEMBER, THE PERIPHERY OF SAID BARRING-STICHT FORMING CAM COMPRISING A RAISED PORTION TO SWING SAID CAM FOLLOWER MEMBER ENGAGING THEREWITH OUTWARDLY FOR A SUBSTANTIAL PORTION OF A HALF ROTATION OF SAID CAM, A RECESSED PORTION TO SWING SAID CAM FOLLOWER MEMBER INWARDLY FOR A SIMILAR PORTION OF A HALF ROTATION OF SAID CAM, PROTRUSIONS AND RECESSIONS PROVIDED AT THE STARTING EDGE OF EACH OF SAID RAISED AND RECESSED PORTIONS TO SWING SAID CAM FOLLOWER AN ODD NUMBER OF TIMES, A FINGERED CLUTCH MEANS MOUNTED ON ONE SIDE OF SAID BARRING-STITCH FORMING CAM TO SELECTIVELY CONNECT THE LATTER FOR ROTATION WITH SAID CAM SHAFT, AND MANUALLY OPERATED MEANS TO ACTUATE SAID CLUTCH MEANS.