US3160126A

US3160126A - Zig-zag sewing machine

Info

Publication number: US3160126A
Application number: US240054A
Authority: US
Inventors: Moro Antonio
Original assignee: Borletti SpA
Current assignee: Fratelli Borletti SpA; Borletti SpA
Priority date: 1961-12-02
Filing date: 1962-11-26
Publication date: 1964-12-08
Anticipated expiration: 1981-12-08
Also published as: GB1007478A; DE1485142A1; CH388746A; BE625401A

Description

Dec. 8, 1964 Filed Nov. 26. 1962 A. MORO ZIG-ZAG SEWING MACHINE 8 Sheets-Sheet 1 Inventor A/vra/v/o M020 Allorney Dec. 8, 1964 Filed NOV. 26, 1962 A. MORO ZIG-ZAG SEWING MACHINE 8 Sheets-Sheet 2 Inventor Aura/W0 Mom Attorney Dec. 8, 1964 Filed Nov. 26, 1962 A. MORO ZIG-ZAG SEWING MACHINE 8 Sheets-Sheet 5 MWJ/MN A llorney Dec. 8, 1964 A. MORO 3,160,126

ZIG-ZAG SEWING MACHINE Filed Nov. 26, 1962 s Sheets-Sheet 4 nventor fl/vrwv/o Maw A Horney Dec. 8, 1964 A. MORO 3,160,126

ZIG-ZAG SEWING MACHINE i/vmwa M020 Byym /w A ttorne y Dec. 8,1964 MQRO 3,160,126

ZIG-ZAG SEWING MACHINE Filed Nov. 26, 1962 8 Sheets-Sheet 6 Fm. 8 r/c. a

Inventor //vm/1//0 Mam A ttorne y Dec. 8, 1964 A. MoRo 3,160,126

ZIG-ZAG SEWING MACHINE Filed Nov. 26, 1962 8 Sheets-Sheet 7 F/G. l4

F/G. l5

Inventor /4/Yr0/V/0 Mafia By 17mm M A ftorne y Dec. 8, 1964 A. MORO 3,160,126

ZIG-ZAG SEWING MACHINE Filed Nov. 26, 1962 8 Sheets-Sheet 8 I n venlor ANTON/0 Mafi Attorney United States Patent C) 3,169,126 ZiG-ZAG SEWING MAQHWE Antonio More, Miian, Italy, assignor to doc. per Antoni Frateiii Borletti, Milan, ltaiy Filed Nov. 2-5, 1962, er. No. 243354 Claims priority, appiication litaly, Dec, 2, 1961, 21,330/61, Patent 13,452 11 Claims. or. ii2153) The present invention relates to a device for controlling in a practical and simple manner the making of buttonholes in a sewing machine of the zigzag type.

In known machines of the zig-zag type, the width of the stitch and the origin of the stitch itself are controlled by the manual operation of two separate members, and, the length of the stitch and the forward or rearward movement of the material are controlled by the manual operation of another member.

For making buttonholes with a zig-zag machine of known type, it is therefore necessary to manipulate these control members for each part of the buttonhole, that is the two cords, on the left and right of the buttonhole as seen by the operator, and the two bars, to the front and rear of the buttonhole as seen by the operator. If, for example, for producing the left-hand cord of the buttonhole, the transport mechanism is adjusted for rearward movement of the material, after the origin of the zig-zag stitch has been set to the left and the desired width of the zig-zag has been set by means of the appropriate controls to produce the front bar of the buttonhole, the transport of the material must, while the length of the stitch remains fixed, be adjusted for forward movement and the control regulating the width of the zigzag must be actuated to obtain the desired width of the bar. Then, to produce the right-hand cord of the buttonhole, it is necessary to act on the control adjusting the origin of the zigzag stitch to the right and again actuate the control regulating the Width of the zig-zag in order to reduce it to that of the cord, the length of the stitch and the direction of transport of the material naturally remaining fixed. Finally, to produce the rear bar of the buttonhole, the transport mechanism must be adjusted again for rearward movement of the material and it is necessary to act again on the control regulating the width of the zig-zag in order to bring it to the width of the bar. The result is that the making of buttonholes wih a zig-zag machine of known type requires special attention and loss of time on the part of the operator, who nevertheless comes up against frequent faults of operation.

In order to overcome these difliculties and eliminate the drawbacks deriving therefrom, sewing machines have already been devised in which there are fitted devices permitting the simultaneous actuation of all three of the above-mentioned control members with a single manipulation. These solutions, however, entail considerable constructional complications, which would be further increased if it were desired to give the operator the possibility of making buttonholes of different widths with the same machine.

The device according to the present invention makes it possible to obtain the same result with a considerable constructional simplicity and moreover aliords the possibility of adjusting the width of the buttonhole at will without adding supplementary members.

An object of this invention is to provide a zig-zag sewing machine in which the tappet lever transmitting its movements under the control of a rotating cam to the link for the transverse actuation of the needle bar in a zig-zag sewing machine provided with means for varying the width of the zigzag is formed in two parts carrying respectively the tappet and the fork engaging the link,

3,15,125 Patented Dec. 8, i964 ice the relative angular position of which around a common pivot is capable of varying against the action of spring return means urging the two parts towards a relative position pre-established through the intervention of means having a manual control which are adapted to arrest in one direction or the other the excursion of that part of the tappet lever which carries the link engaging fork so as to permit utilization of all or part of the pro-selected width of the zig-zag for producing respectively the bars and the cords of the buttonhole.

These and other objects of the invention will appear more clearly from the following description of a number of embodiments of the invention which are illustrated by way of non-limitative example in the accompanying drawings, in which:

FIG. 1 shows a complete buttonhole of pre-established dimensions,

FIGS. 2A, 2B, 2C and 2D show the successive stages in the making of the same buttonhole,

FIGS. 3 to 6 are diagrammatic partial front views of a zig-zag sewing machine incorporating the device according to the invention, in the positions for producing the left-hand cord, the front bar, the right-hand cord and the rear bar, respectively, of the buttonhole,

FIGS. 3A and 3B illustrate in two different positions a modified constructional form of a detail of FIGS. 3 to 6,

FIG. 7 is an end view, partly in section, of the device illustrated in FIGS. 3 to 6,

FIG. 8 shows a detail in section on the line VIII-VHI of FIG. 7,

FIGS. 9 to 11 are an external view, an axial section and an inside view of the control knob of the device for making the buttonhole,

FIGS. 12 and 13 are views similar to those of FIGS. 10 and 11 of a modified constructional form of the control knob,

FIG. 14 is a partial view of a modified constructional form of the device in a position corresponding to that of FIG. 5,

FIG. 15 is a section on the line XVXV of FIG 14,

FIG. 16 shows another alternative construction in a position corresponding to that of FIG. 4, and

FIG. 17 shows the application of the device/according to FIGS. 3 to 6 to a machine equipped with a different type of control cam.

The zig-zag sewing machine illustrated (FIGS. 3 to '6) has a main driving shaft 1 which transmits its rotation to a shaft 2, on which a cam 3 is fixed, by means of a toothed Wheel 4 meshing with a wheel 5 fixed to the shaft 2.

The cam 3 has a certain number of teeth or peripheral projections 6 on which there rests under pressure, due to the etfect of a spring 7, the tappet 8 of a lever 9 pivoted on a fixed spindle It). The transmission ratio between the shaft 1 and the shaft 2 and the number of teeth of the cam 3 are chosen in such manner that for each revolution of the shaft 1 the lever 9 performs a half oscillation.

The lever 9 is pivoted loosely on a sleeve 11 which, in turn, is mounted rotatably on the fixed spindle 10. Fixed for rotation with the sleeve 11 is a lever 12 having two

arms

15 and 16, the first of which carries a fork 17 controlling a tie rod or link 18 for the transverse actuation of the needle bar and is superposed on a radial extension 19 of the lever 9 with which it is associated by means of a screw 2t} (FIG. 8) which, on being screwed into a lug 21 of the arm 15, bears with its end 20 against a lug 22 of the extension 19, against which latter lug it is urged by the action of a spring 23 the two ends 23 and 23" of which are hooked over the arm 15 and the arm 9, respectively.

The other arm 16 of the two-armed lever 12 terminates i; in a fork 24 with the two arms thereof having divergent facing

surfaces

24, 24", which cooperates with an eccentric 25 fast with a spindle 26 (FIG. 10) provided with a manual control knob 27, for determining the position of the arm 16. 1

Also fast with the spindle as is an eccentric 28 cooperating with a resilient strip 29 fixed to a member 36? forming part of a mechanism of known type for controlling the shifting of the transport of the material and comprising cams 31, a lever 32 subject to the action of a return spring 33 and a slider 34 regulating the movements of a connecting rod 35 which, in turn, impresses the movements on the transporter.

In order to avoid breakages or deformations of the resilient strip 29 due to incorrect operation of the knob 27 and of the elements 31 and 3%, instead of connecting said resilient strip rigidly to the element 3t) as indicated in FIGS. 3 to 6, itis fixed, according to a modified constructional form illustrated in FIGS. 3A and 313, to a rigid strip 36 pivoted at 37 to the member 3% and kept in contact with a pin 38 of said member by means of a spring 39. In condition of rest, a gap 40 is left between the resilient strip 29 and the rigid strip 35 to enable the strip 29 to bend to the extent necessary for it to function, but up to a maximum limit after which it bears against the rigid strip 36, which prevents it from becoming permanently deformed or being broken owing to the effect of possible misoperation. If the resilient stripZQ should happen to be located accidentally to the right of the eccentric 28 (FIG. 313), this arrangement also allows the element 30 to be operated in the direction of the arrow f by means of the cams 31 so as to cause the strip 29 to rotate in engagement with the end 28' of the eccentric 28, on the pin 37, and, on overcoming the spring 39,

to cause the strip to snap to the left of the eccentric 28.

In the embodiment according to FIGS. 3 to 6, the fork 24 is mounted on the arm 16 of the two-formed lever 12, so as to be adjustable along the axis of said armf this end, the shank of the fork and the arm 16 have two

slots

41 and 42, respectively, aligned on said axis and in the first of which there is engaged a guide pin 43 of the arm 16, while through the second slot there extends a clamping screw 44' carried by the shank of the fork and which locks the latter in the desired position. This arrangement, together with the divergence of the facing

surfaces

24, 24 of the two arms of the fork, allows the relative positions of the fork 24 and the eccentric 25 to be adjusted easily during the assembly stage in such man-.

in accordance with the modified constructions illustrated in FIGS. 14 and 15 and in FIG. 16, respectively. Ac-

cording to FIGS. 14 and 15, the two facing

surfaces

2 and 24" of the fork connected to the arm 16 of the twoarm-ed lever 12 form part of branches 4E, 46, respectively.

which are constructionally separated and pivoted independently of one another to the arm 16. is pivoted at 4'7 and can be locked in the desired position on the arm 15 by means of the screw 48 extending through the arcuate slot 49 in the arm 16.

In completely similar manner, the branch 46 is pivoted to the arm at 50 and can be locked on said arm by the screw 51.

According to FIG. 16, the facing surfaces 24', 24 of the forkstill form part of

arms

45, 46 respectively, which are constructionally separate and adapted to assume an-,

' gular positions which can be adjusted independently.

In contrast to the embodiment according to FIGS. 14 and 15, however, the arm is pivoted at 47' to a second extension 52 of the lever 9 and only the arms 46 is pivoted at to the arm 16 of the fork 1.2. The fixing of the

arms

45, 46 in the desired angular position-is obtained by means of screws 43', 51' respectively, extending through slots 4? in the extension 52 and the arm 16.

The branch 45 In practice, one or the other of the embodiments described may be chosen or constructed according to the type of machine in which the device is fitted.

The knob 27 controlling, on the one hand, the positions of the arm 16 of the two armed lever 12 and, therefore, of this same lever and, on the other hand, the amplitude and direction of the transport of the material can assume four positions with respect to a fixed index 53. In the embodiment according to FIGS. 9 to 11, these positions are determined by the engagement of a resilient tooth 5 of a ring 55 fixed to the frame 56 with the edge 57 of radial grooves 58 in the rear face of the knob 27., In the embodiment according to FIGS. 12 and 13, on the other hand, there is provided a plunger 59 slidable in a radial hole 66 in the boss 56 on the frame 56 which supports the spindle 26, and placed under the action of the spring 61 which causes said plunger to adhere to cylindrical surfaces 62 having a helical profile which are disposed on the inside of the knob 27 and terminate in radial stop surfaces 63. Both arrangements permit rotation of the knob 27 only in the direction of the arrow f, thus preventing wrong operation. The knob 27 carries on the front of its rim 2.7, in correspondence with the grooves 53 or the surfaces 63; special symbols :1, b, c, d, which may also be simple numbers, indicating the operations which are carried out by the machine when these symbols are brought into correspondence with the fixed index 53. The special symbols, or numbers, may be arranged with equivalent results on the fixed part, at the periphery of the knob, and the index on the knob.

Referringparticularly to FIGS. 3 to 6, it is obvious, from what has been said above, that the lever 9 can move angularly in the direction of the arrow i", that is clockwise as seen in the drawing, overcoming the action of the spring 23 and causing the lug 22 to move away from the tip 263 of the screw 2t} when the lever 12 is locked in the direction of the arrow 1. This occurs under the thrust exerted in the direction of the arrow 1" by the teeth 6 of the cam 3 against the tappet 8 of the lever 9. How- .ever, as soon as the locking of the lever 12 ceases, the tip Ell" of the screw 20 comes into contact with the lug 22 again under the restoring action of the spring 23 and the'lever 12 returns to form a single group with the lever 9 and to move together therewith as if it were a single piece with it.

If, on the other hand, the lever 12 is locked in an anticlockwise direction, that is in the direction opposite to the arrow any shifting of the lever 9 in an anti-clockwise direction from the position in which the lug 22 engages with the tip 20' of the screw 20 is prevented. Therefore, in the condition considered, the lever 9 remains fully or partially raised with respect to the teeth 6 of the cam 3 and said teeth impress on the tappet S and, therefore, on the lever 9, angular movements about the spindle ill which are reduced in relation to the position of the blocking of the lever 12. a

The result obtained, therefore, is that, while the cam 3 rotates steadily, the end 17" of the lever 12, which imparts the transverse movements for the zig-Zag to the'needle bar through the tie rod 18, is controlled in position and amplitude of its oscillations.-

The locking or arresting of the lever 12 in one direction or the other is obtained by means of the eccentric 25 operated by the knob 27.

In the position shown in FIG. 3, to which there co responds the position a of the knob 27 (FIG. 9), the eccentric 25 is rotated so that its surface of maximum radius is in contact with the surface 24' of the fork 24. Under these conditions, the tappet 8 cannot touch the base of the teeth 6 of the cam, because the group consisting of the

levers

12 and 9 is arrested in its anti-clockwise oscillation by contact of the surface 24' with the eccentric 25. The excursion of the lever 9 is therefore limited between the positions 9 and 9' and that of the fork 17 between the

direction

17 and 17". The needle bar is therefore given transverse movements to the left of a length limited between the positions A and A (FIG. 3), thus forming the left-hand cord :1. of the buttonhole (FIG. 2A). Since it is appropriate that, during the formation of this part of thebuttonhole, the material should move to the rear, that is towards the operator, the adjustment of the transport must be prearranged accordingly.

For this purpose, there is used the second eccentric 28 which in the position shown in FIG. 3, pushes the strip 29 so as to bring the known element 30 and, therefore, the lever 32 and the slider 34 regulating the movements of the connecting rod 35 which, in turn, imparts the movements to the transporter, into a position to ensure the direction of movement of the material.

When the left-hand cord has been produced, the knob 27 is prearranged for the upper bar. For this purpose, the knob 27 is rotated through 90 so that the symbol b comes into coincidence with the index 53. In this position (FIG-4), the

eccentrics

25 and 23 are no longer in contact with the surface 24' of the fork 24 and with the strip 29', respectively. The lever 12 is therefore completely free to perform the complete oscillations imparted by the teeth 6 of the cam 3 and the lever 32 of the control device of the transporter returns to the position of forward transport of the material because of the spring 33. The fork 17, being no longer impeded, transmits to the needle bar the maximum transverse zig-zag movemerits, causing the needle to shift alternately from the position B to the position B, so as to form the front bar b (FIG. 2B).

When the front bar has been produced, the knob 27 is rotated by another step, causing the symbol c to coincide with the index 53. In this position (FIG. 5), the eccentric 25 is disposed in contact with the surface 24" of the fork 24-, while the eccentric 28, not touching the strip 29, leaves the transporter prearranged for moving the material forward. On rotation of the cam 3, the teeth 6 cause the lever 9 to perform complete oscillations, but, the lever 12 being arrested, after a pre-fixed stroke, by contact of the surface 24" with the eccentric 25, the fork 17 also stops after a given stroke from right to left and, consequently, also the needle bar which oscillates between the positions C and C. From the instant when the surface 24" comes into contact with the eccentric 25, the lever 9 continues its upward travel, overcoming the action of the spring 23 and removing the lug 22 from the tip 20' of the screw 20. The oscillations limited in breadth in this way and starting with a right-hand origin give as a result the formation of the right-hand cord c (FIG. 20

By a final rotation of the knob 27 through 90, the symbol d is brough into coincidence with the index 53. In this condition (FIG. 6), the eccentric 25 is no longer in contact either with the surface 24 or with the surface 24" of the fork 24. Therefore, the group 9-12 is subjected, without any stop, to the oscillations imparted by the teeth 6 of the cam to the tappet 8, which oscillations the fork 17 transmits to the needle bar, which moves between the positions D and D for the formation of the rear bar 0! (FIG. 2D).

For producing the latter, the transporter must cause the material to run to the rear, that is towards the operator. Therefore, in the position of the knob 27 in which the symbol 0! coincides with the index 53, the eccentric 28 pushes the strip 29 so as to bring the lever 32 back to the position of rearward movement, equivalent to that of FIG. 3.

The production of the final bar d having been completed (FIG. 2D), the knob 27 is returned to the position in which the symbol b is in coincidence with the index 53. In this position, in fact, the

eccentrics

25, 28 leave the fork 24 and the strip 29 completely free for all the normal movements of the levers 9-12 and of the device for controlling the transport of the material, as will be seen in FIG. 4. The particular form of the eccentric 28 which can be seen from the drawings is determined precisely by the need to allow the device-with which the strip 29 is associated-the possibility of performing without any impediment, the widest angular movements for adjusting the length of the stitch from zero to a maximum both in the forward and in the rearward direction.

As the total width of the zig-zag and, therefore, of the buttonhole is determined by the position of the pivot 54 (FIG. 7) with respect to the oscillation pivot 65 of the rocking lever 66, it follows that it is sufficient to vary the distance (FIG. 7) to vary the Width of the buttonhole. This is done by operating the knob 67 in the direction of the arrows F. In this Way, the lever 68 is made to turn about the fulcrum 69 and, through the connection 70 and'the rod'71', the position of the pivot 64 is adjusted with respect to the axis of the pivot 65. These known elements are generally fitted in zig-zag machines for the purpose-of controlling the width of the zigzag stitch and are used according to the present invention to obtain buttonholes of different widths in an extremely simple manner.

It is obvious that the device described can also function with cams of a type different to that indicated by the reference 3 in the foregoing description, it being only essential, as stated at the beginning, that the-transmission ratio between the main shaft and the shaft of the cam and the number of teeth ofthe cam be choosen in such manner that the lever carrying the tappet performs a half oscillation at each revolution of the main shaft. In the case described above, for example, in which the cam has twelve teeth, it is provided that the main shaft performs 24 revolutions for one revolution of the cam. This is a question of a machine of knowntype designed for producingautomatically cyclic zig-zag seams of 24 stitches. FIG. 17, on the other hand, illustrates the application of the invention to the case of a machine, the main shaft of which performs two revolutions for one revolution of the cam. This is a question of a normal zig-zag machine which cannot produce automatically cyclic zig-zag seams with more than two stitches. In this case also, however, as in other equivalents, the device according to the present invention may be usefully applied.

What I claim is:

1. A zigzag-stitch sewing machine for making buttonholes comprising:

(a) a frame,

(b) a drive shaft rotatably mounted in said frame,

(c) a needle bar guide pivoted on said frame,

(d) a needle bar slidably mounted on said needle bar guide,

(e) a cam actuated by saiddrive shaft, said cam having an outer periphery comprised of alternate raised and lowered surfaces,

(f) a fixed spindle mounted on said frame,

(g) a first two-armed lever swingingly mounted on said fixed spindle,

(h) a cam follower supported by one arm of said first two-armed lever engaging said cam,

(i) a second two-armed lever swingingly mounted on said fixed spindle coaxial to said first two-armed lever,

(i) a fork supported by one arm of said second twoarmed lever engaging a tie rod; said tie rod being connected to said needle bar guide,

(k) stopping members provided on said levers,

(l) spring means cooperating with said stopping members to engage said first and second two-armed levers so that the reciprocal angular position of said first and second two-armed levers can be modified in one direction, and by said spring means and said stopping members a swing imparted by said cam to said first lever is transmitted to said second lever, and

(m) manual control means for limiting the oscillation of said second lever in a direction of rotation so as to allow preselected widths of a zigzag stitch to be used for making bars and cords of a buttonhole. 2. The zigzag-stitch sewing machine as defined in claim 1, wherein said manual control means (m) controls the direction of transport of material.

3. A zigzag-stitch sewing machine for making buttonholes comprising: (a) a frame, (b) a drive shaft rotatably mounted in said frame, (c) a needle bar guide pivoted on said frame, (d) a needle bar slidably mounted on said needle bar guide, a cam actuated by said drive shaft, said cam having an outer periphery comprised of alternate raised and lowered surfaces,

(7) a fixed spindle mounted on said frame,

(g) a first two-armed lever swingingly mounted on said fixedspindle,

(i) a second two-armed lever swingingly mounted'on said fixed spindle coaxial to said first two-armed lever,

(j) a first fork supported by one arm of said second two-armed lever engaging a tie rod, said tie rod being connected to said needle bar guide,

(k) a second fork supported by the other arm of said second two-armed lever,

(l) stopping members provided on said levers,

(m) spring means cooperating with said stopping members to engage said first and second two-armed levers so that the reciprocal angular position of said first and second two-armed levers can be modified in one direction, and by said spring means and said stopping members a swing imparted by said cam to said first lever is transmitted to said second lever, and

(n) an eccentric mounted on said frame coaxial with and actuated by hand-setting means, said eccentric engaging said second fork of said second lever for limiting the oscillation of said second lever in a direction of rotation "so as to allow preselected widths of a zigzag stitch to be used for making bars and cords of a buttonhole.

4. A zigzag-stitch sewing machine for making buttonholes comprising:

(a) a frame,

(b) a drive shaft rotatably mounted in said frame,

(0) a needle bar guide pivoted on said frame,

(d) a needle bar slidably mounted on said needle bar guide,

(e) a cam actuatedby said drive shaft, said cam having an outer periphery comprised of alternate raised and lowered surfaces,

(f) a fixed spindle mounted on said frame,

(3) a first two-armed lever swingingly mounted on said fixed spindle,

(h) a cam follower supported by one arm of said first two-armed lever'engaging said cam,

(k) a second fork supported by the other arm of said second two-armed lever,

(Z) stopping members provided on said levers,

(m) spring means cooperating with said stopping members to engage said first and second two-armed levers so that the reciprocal angular position of said first and second two-armed levers can be modified in one direction, and by said spring means and said stopping members a swing imparted by said cam to said first lever is transmited to said second lever,

(n) a transport control mechanism attached to said frame for control of the direction of movement of material being sewed,

(0) a first eccentric mounted on said frame coaxial with and actuated by hand-setting means, said first eccentric engaging said second fork of said second lever for limiting the oscillation of said second lever in a direction of rotation so as to allow preselected widths of a zigzag stitch to be used for making bars and cords of a buttonhole, and

(p) a second eccentric mounted on said frame coaxial with and actuated by said hand-setting means, said second eccentric engaging said transport control mechanism and controlling the direction of material being sewed.

5. The zigzag-stitch sewing machine as defined in claim 4, wherein a resilient strip has one end attached to said transport control mechanism (It) and the other end of said resilient strip engages said second eccentric (p).

6. The zigzag-stitch sewing machine as defined in claim 5, wherein said resilient strip engages said second eccentric by spring means. I

7. The zigzag-stitch sewing machine as defined in claim 5, wherein said resilient strip is mounted on a rigid strip which prevents bending said resilient strip beyond a selected safety limit, and said rigid strip is mounted on said transport control mechanism.

8. The Zigzag-stitch sewing machine as defined in claim 12, wherein said stopping members (k) are adjustable so that said first and second two-armed levers may be adjusted with respect to one another.

9. The zigzag-stitch sewing machine as defined in claim 3, wherein. said second fork (k) supported by the other arm of said second two-armed lever comprises two adjustable arms.

10. The zigzag-stitch sewing machine as defined in claim 3, wherein said second fork (k) supported by the other arm of said second two-armed lever comprises two mechanically separate arms pivoted on said other arm of said second two-armed lever so that the angle of divergence of said second fork can be varied.

, 11. A zigzag-stitch sewing machine for making buttonholes comprising: a

(a) a frame,

(1)) a drive shaft rotatably mounted in said frame,

(c) a needle bar guide pivoted on said frame,

(a') a needle bar slidably mounted on said needle bar guide,

(e) a cam actuated by said drive shaft, said cam having an outer periphery comprised of alternate raised and lowered surfaces,

(7) a fixed spindle mounted on said frame,

(g) a three-armed lever swingingly mounted on said fixed spindle,

(h) a cam follower supported by one arm of said threearmed lever engaging said cam,

(i) a two-armed lever swingingly mounted on said fixed spindle coaxial to said three-armed lever,

(j) a first fork supported by one arm of said two-armed lever engaging a tie rod, said tie rod being connected to said needle bar guide,

(k) stopping members provided on said levers,

(1) spring means cooperating with said stopping members to engage said three-armed and two-armed levers so that the reciprocal angular position of said levers can be modified in one direction, and by said spring means and said stopping members a swing imparted preselected widths of a zigzag stitch to be used for FOREIGI} I ATENTS making bars and cords of a buttonhole. 517,363 2/55 Italy.

References Cited by the Examiner 37-11589 8/62 Japan.

N TE TA E PATENTS 5 JORDAN FRANKLIN, Primary Examiner. 2,972,319 2/51 Moro 112-158 DAVID J, WILLIAMOWSKY, Examiner.

3,068,817 12/62 Hamlett 112-158

Claims

1. A ZIGZAG-STITCH SEWING MACHINE FOR MAKING BUTTONHOLES COMPRISING: (A) A FRAME, (B) A DRIVE SHAFT ROTATABLY MOUNTED IN SAID FRAME, (C) A NEEDLE BAR GUIDE PIVOTED ON SAME FRAME, (D) A NEEDLE BAR SLIDABLY MOUNTED ON SAID NEEDLE BAR GUIDE, (E) A CAM ACTUATED BY SAID DRIVE SHAFT, SAID CAM HAVING AN OUTER PERIPHERY COMPRISED OF ALTERNATE RAISED AND LOWERED SURFACES, (F) A FIXED SPINDLE MOUNTED ON SAID FRAME, (G) A FIRST TWO-ARMED LEVER SWINGINGLY MOUNTED ON SAID FIXED SPINDLE, (H) A CAM FOLLOWER SUPPORTED BY ONE ARM OF SAID FIRST TWO-ARMED LEVER ENGAGING SAID CAM, (I) A SECOND TWO-ARMED LEVER SWINGINGLY MOUNTED ON SAID FIXED SPINDLE COAXIAL TO SAID FIRST TWO-ARMED LEVER, (J) A FORK SUPPORTED BY ONE ARM OF SAID SECOND TWOARMED LEVER ENGAGING A TIE ROD, SAID TIE ROD BEING CONNECTED TO SAID NEEDLE BAR GUIDE, (K) STOPPING MEMBERS PROVIDED ON SAID LEVERS, (L) SPRING MEANS COOPERATING WITH SAID STOPPING MEMBERS TO ENGAGE SAID FIRST AND SECOND TOW-ARMED LEVERS SO THAT THE RECIPROCAL ANGULAR POSITION OF SAID FIRST AND SECOND TWO-ARMED LEVERS CAN BE MODIFIED IN ONE DIRECTION, AND BY SAID SPRING MEANS AND SAID STOPPING MEMBERS A SWING IMPARTED BY SAID CAM TO SAID FIRST LEVER IS TRANSMITTED TO SAID SECOND LEVER, AND (M) MANUAL CONTROL MEANS FOR LIMITING THE OSCILLATION OF SAID SECOND LEVER IN A DIRECTION OF ROTATION SO AS TO ALLOW PRESELECTED WIDTHS OF A ZIGZAG STITCH TO BE USED FOR MAKING BARS AND CORDS OF A BUTTONHOLE.