US1931556A

US1931556A - Thread trimmer for buttonhole sewing machines

Info

Publication number: US1931556A
Application number: US600081A
Authority: US
Inventors: Joseph H Pikul
Original assignee: Reece Button Hole Machine Co
Current assignee: Reece Button Hole Machine Co
Priority date: 1932-03-21
Filing date: 1932-03-21
Publication date: 1933-10-24
Anticipated expiration: 1950-10-24

Description

Oct. 24, 1933. J. H. 'p u 1,931,556

THREAD TRIMMER FOR BUTTONHOLE SEWING MACHINES Filed March 21, 1952 3 Sheets-Sheet 1- Fig.1.

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06L 24, 1933. H. P|KUL 1,931,556

THREAD TRIMMER FOR BUTTONHOLE SEWING MACHINES Filed March 21, 1932 3 Sheets-Sheet 2 lnvenTon- \JosephHPiKu! Anys.

b zwa @MW Oct. 24, 1933. J. H. PIKUL 1,931,556

THREAD TRIMMER FOR BUTTONHOLE SEWING MACHINES Filed March 21, 1932 3 Sheets-Sheet 3 7 Fig.5.

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Patented Got. 24, 1933 PATENT OFFICE THREAD TRIMMER FOR BUTTONHOLE SEWING MACHINES Joseph H. Pikul, Troy, N. Y., assignor to The Reece Button Hole Machine Company, Boston,

Mass, a corporation Application March 21,

16 Claims.

invention relates to thread-trimming devices for buttonhole-sewing machines by which the leading from the under side of the k at the completion of the buttonhole, and the stay cord, if one is used in sewing the buttonhole, are out close to the work at the completion of the sewing operation, and the invention has particular reference to such thread-trimining devices in which the cutting of the thread is accorn rished a er the have been opened. One of the objects of the invention is to provide improvements in thread-cutting devices of this type by which the tl.. 'ead or threads leading from I the under side of the work can becut closeto the work without danger of cutting or injuring the buttonhole stitches or the fabric or other materiai in which the buttonhole is sewed;

Most buttonhole sewing machines are con- I structed so that the buttonhole. is sewed with the direction of the length thereof, these superposed.

lines of stitching lying on the face ofthe goods and thus producinga rib efiect.

' ting any of the threads forming the fly bar of the In some buttonhole sewing machines the thread-trimming device which trims-the thread underneath the work at the completion of the butter mic is provided with a thread-cutting edge situated and operating substantially in the plane of the under face of the work. I

it is one of the objects of the present invention to provide an improvement in thread-cutting devices of this type which will operate to separate the work from the cutting edge of the thread cutter sufficiently so that the thread may be trimmed close to the work without danger of cut buttonhole. This is provided for by means which I operates after the work clamps have been opened but before the thread is cut to lift the work sufficiently so that the stitches of the fly bar will be cleared from the cutting edge of the thread cutter. I

In order to give an understanding of the invention I have iilustrated in the drawings some selected embodiments thereof which will now be describedafter which the novel features will be pointed out in the appended claims.

v Fig. l is a side view of a portion of a buttonhole sewing machine embodying my invention;

In the sewing of of Maine 1932. Serial No. 600,081

Fig. 2 is a top plan view of the work clamps; Fig. 3 is a View of the work-lifting plate; Fig. 4 is a section on the line 4-4, Fig. 2;

Fig. 5 is an under side view of the clamp plates and thread-cutting mechanism;

Fig. 6 is a fragmentary view showing the means for operating the thread trimmer;

Fig. '7 is a section on the line 7-7, Fig. 5;

Fig. 8 is a section on the line 8--8, Fig. 2 showing the position of the parts at the completion of the buttonhole sewing but before the work is unclamped; I

Fig. 9 is a similar view showing the position of the parts after the work is unclamped and has been raised. and just' before the thread is cut;

Fig. 10 is a sectional view similar to Fig. 7 but showing the parts after the clamps have. been raised and the work-lifting plate has been actuated to lift the work. I

Fig. 11 is a view showing the thread-cutting elements;

Fig. 12 is a view of a fly bar buttonhole.

The sewing machine shown in Fig. 1 is of. that type which comprises a bed frame 1 carrying work-holding means in which the work 2 is held during the sewing operation, and which also I comprises astitch frame 3 carrying the stitch forming mechanism, said stitch-forming mecha. nism having a feeding movement relative to the work-holding means during the sewing operation and a further relative movement after the stitch-forming mechanism comes to rest to. carry the parts from stitching position to buttonholecutting position. I .I

The work-holding means is mounted on the usual clamp plates 4 that are removably carried by the'bed 1. Said work-holding means includes the roughened plates or

mats

5, 6 that are secured to the clamp plates 4, and clamping

feet

7, 8 which clamp the work against the mats 5' and 6. These clamping feet are carried by clamp arms 9 pivoted to the clamp plates 4 at 10 as usual in buttonhole sewing machines of this type. The

clamps

7 and 8 are operated by the usual mechanism which causes themto close onto the work before the sewingon the buttonhole begins and holds them clamped against the work during the sewing operation and which releases them at the completion of the sewing operation.

The stitch-forming mechanism is of the usual type which comprises a needle 11 operating from above the work and carrying a needle thread 65,

and loopers or their equivalent operating beneath the work and carried. by a rotary turret 12 which many respects to the thread cutter shown in, my

' clamp plates 4. The cutting element 19 is in avvay'to receive said blade 19 when it' is in its under thread 32 and stay cord 33 p clamping foot 8. is alsoin the form of a blade having a cutting is journalled in

bearings

13, 14 carried by the lower portion 15 of the stitch frame 3, said turret carrying at its upper end the usual throat plate 16 which is provided with the sewing opening 17 through which the needle 11 operates and through which the under thread 32 and stay cord 33 are led to the sewing point.

The needle l'l'is mounted in the usual needle bar 18 which is mounted both for reciprocation on the stitch frame 3 and for turning movement therein as usual in buttonhole sewing machines of this type.

In the sewing machine herein shown the necessary relative movement between the stitchforming mechanism and work-holding means is secured by a movement of thestitch frame 3 back and forth on the bed frame 1, and as will be understood from those familiar with buttonhole sewing machines of this type the stitchforming mechanism and work-holding means have a relative feeding movement during the sewing of the buttonhole and when the sewing operation is complete the stitch-forming mechanism comes to rest with the needle raised as indicated in Fig. l and the stitch forming mechanism and work-holding means then have a further relative movement to carry the work from stitching to buttonhole-cutting position, which is the dotted line position shown in Fig. 1. During such further relativemovernent a length of is drawn through the throat plate 16, such lengths of under thread and stay cord lying underneath the work.

The thread cutter herein shown is similar in co p ending application iderial No.- 585,0'l3,' filed January 6, 1932. Such thread cutter comprises two cutting elements-19 and 20 which are coaxially pivoted on a stud 21 carried by one of the the form of a blade having a cutting edge 22 and situated beneath the clamping foot 8 and having its upper face flush with the work-supporting surface of the mat 6, said mat being out inoperative position. ihe upper face of the blade 19 thus forms part of the work supporting' surface against which the work is clamped by the The thread-cutting member 20 edge 23 which normally extends transversely to the line of stitching'when the thread cutter is in its inoperative position.

Both of the blades are provided with hub'portions through whichthe pivot stud 21 extends,

the hub portion of the blade 19 being indicated at 24 and that of the blade 20 at 25. These two hub portions are superposed one on the other.

of' the work. Saidoutter is actuated by means similar to that shown in my copending applica tion Serial No. 535,073.

Each of the cutter elements is provided with a tail portion 26 between which is situated a cam member 2'? carried by a rock shaft 28 journalled in one of the clamp plates 4. This rock shaft extends below the clamp plate and on its lower end it is provided with an arm 29 having a depending portion 39 that is adapted to be engaged by an upstanding arm Slthat is carried bythe turret 12.

- In these buttonhole sewing machines it 'willbe The thread cutter is thus situated directly be-' neath'the work and normally or during the sewbuttonhole-cutting position and at the same time drawing out through the throat plate a length 32 of under thread and a length 33 of stay cord which extends from the last stitch to the throat plate.

'After the parts have been carried into buttonhole-cutting position, which is the position shown in Fig. 8, the clamps are opened as shown in Figs. 9 and 10 and after the clamps are opened the rotation of the turret 12 actuates the

thread cutters

19 and 20 to cut the

lengths

32, 33 of thread extending from the under side of the work to the throat plate.

In sewing a fiy bar buttonhole 34, such as shown in Fig. 12, the bar portion 35 of the buttonhole is formed by two overlying rows of stitching situated in the center line of the buttonhole, one line of stitching being formed at the beginning of the sewing operation and the other at the completion of the sewing operation. The superposed lines of stitches present a rib-like projection on the under face of the goods which eX- tends from the last stitch to the buttonhole slit.

When the parts are being carried from stitching to buttonhole-cutting position and the lengths of under thread and stay

cord

32, 33 are being drawn through the throatplate, the strain on the thread tends to pullthe work down against the cutting blades.

As stated above, one of the objects of the present invention is to provide for manipulating the Work at the time that the

lengths

32, 33 of thread are cut so as to obviate any danger that the cutters will damage either the goods or the stitches constituting the bar 35 of the buttonhole. This is done by providing means for separating the goods slightly from the work-supporting surface after the clamps '7 and 8 have been released and before the

lengths

32, 33 of thread are cut, such raising movement being sufficient to ensure that the stitches forming the bar. 35 are separated sufficiently from the path of movement of the cutting edges of the

thread cutters

19 and 20 so

that'the thread lengths

32, 33 will be out without any injury to the stitches forming the bar portion 35 of the buttonhole.

- Foraccomplishing this I provide a Work-lifting plate which is situated underneath the work and between the latter and the clamp plates 4 and which is lifted from the clamp plates slightly after the work clamps 7, 8 have been released and before the thread is actually cut.

Such work-lifting plate is indicated at 36 and the buttonhole is completed at the'end of the sewing operation the throat plate 16 will be located between the two

extensions

39 and 40 as shown in Fig. 2.

Means are provided for raising the free end of the work-lifting plate 36 after the work clamps '7 and 8 have been released. In the construction herein shown this work-lifting movement of the plate 36 is derived from the cutting movement given to the thread-cutting blades. Said plate is shown as having a rounded projection ll on its under face which, when the cutting blades are in their open position, occupies an opening or recess {L2 in the cutting blade 20, the plate 36 at such time lying flatly against the upper face of the cutting blade 20. When the cutting blades receive their initial thread-cutting movement a pressure of the wall of the opening 42 against the rounded projection 41 will cam the projection upwardly and force it out of the opening thereby raising the work-lifting plate 36, into the position shown in Figs. 9 and 19. During the remainder of the thread-cutting movement of the blade 20 the projection 41 will ride on the top of said blade and thus hold the work-lifting plate in its raised position. This raising of the work-lifting plate 36 lifts the work as shown in Figs. 9 and 10, such lifting movement being suilicient to carry the stitches forming the bar portion 35 of the buttonhole sufficiently above the cutting edges of the

cutting blades

19 and 20 so that the

thread lengths

32 and 33 may be cut close tothe work without danger of injuring either the stitches 35 of the buttonhole or the goods.

When the thread-cutting blades return to their normal or open position the aperture 42 will be brought underneath the projection 41 and the resiliency of the plate 36 will cause the projection 41 to enter the aperture again and the plate 36 to resume its normal position lying flatly against the thread-cutting blade 20 and with the ends 39' and i0 lying against the Work-supporting surface.

I claim:

1. In a buttonhole sewing machine, in combina tion, stitch-forming mechanism, work-clamping means which clamp the work during the sewing of the buttonhole and which release the work at the end of the sewing, thread-cutting mechanism operating beneath and in close adjacency to the work, means to actuate the thread-cutting mechanism after the clamps have released the work, and means operating subsequent to the release of the clamps but before the thread is out to separate the work from the thread-cutting mechanism.

2. In a buttonhole sewing machine, in combination, stitch-forming mechanism, workclamping means which clamp the work during the sewing of the buttonhole and which release the work at the end of the sewing, thread-cutting movement between the work and the thread-cnt- I ting mechanism.

3. In a buttonhole sewing machine, in combination, stitclvforming mechanism, workclamping means which clamp the work during the sewing of the buttonhole and which release the work at the end of the sewing, thread-cutting mechanism operating beneath and in close adjacency to the work, means to actuate the thread-cutting mechanism after the clamps have released the work, and means operating subsequent to the release of the clamps but before the thread is cut to raise the work from the threadcutting mechanism.

4. In a buttonhole sewing machine, in combination, stitch-forming mechanism, work-clamping means which clamp the work during the sewing of the buttonhole and which release the work at the end of the sewing, thread-cutting mechanism operating beneath and in close adjacency to the work, means to actuate the thread-cutting mechanism after the clamps have released'the' work, and means actuated by the thread-cutting mechanism to produce a relative separating movement of the work and said thread-cutting mechanism before the thread is cut,

5. In a buttonhole sewing machine, in combination, stitch-forming mechanism, work-clamping means which clamp the work during the sewing of the buttonhole and which release the work at the end ofthe sewing, thread-cutting mechanism operating beneath and in close adjacency to the work, means to actuate the thread-cutting mechanism after the clampshave released the work, and means actuated by the thread-cutting mechanism to raise the work from the latter before the thread is cut.

6. In a buttonhole sewing machine, in combination, stitch-forming mechanism, work-clamping means which clamp the work during the sewing of the buttonhole and which release the work at the end of thesewing, thread-cutting mechanism comprising a pair of cutting blades operating in planes parallel to the work and in close adjacency thereto, means to give said blades their thread-cutting movement after the clamps have released the work, and means to produce a relative separating movement between the work and said blades subsequent to the release of the clamps but before the thread is cut.

'7. In a buttonhole sewing machine, in combination, stitch-forming mechanism, work-clamping means which. clamp the work during the sewing of the buttonhole and which release the work at the end of the sewing, thread-cutting mechanism comprising a pair of cutting blades operating in planes parallel to the work and in close adja cency thereto, means to give said blades their thread-cutting movement after the clamps have released the work, and means to raise the work from the blades after the clamps have released thework and before the thread is cut.

8. In a buttonhole sewing machine, in combination, stitch-forming mechanism, work-clamping-means which clamp the work during the sewing of the buttonhole and which release the work at the end of the sewing, thread-cutting mechanism comprising a pair of cutting blades operating in planes parallel to the work and in close adjacency thereto, means to give said blades their thread-cutting movement after the clamps have released the work, and means actuated by the thread-cutting movement of the blades to raise. the work from the blades after the clamps have been released and before the thread is cut.

9. In a buttonhole sewing machine, in cornbi- 10. In a buttonhole-sewing machine, in combination, stitch-forming mechanism, work-clamping means comprising clamp plates against which the work is clamped, two co-operating thread-trimming elements situated on top of the clamp plates and beneath the work, means to actuate said elements to cut thread, and means actuated by said thread-trimming elements to separate the work therefrom before the thread is cut.

11. In a buttonhole sewing machine, in combination, stitch-forming mechanism, work-clamping means which clamp the work during the sewing on the buttonhole and which release the work at the end of the sewing, a throat plate through which the thread is led to the work, said stitch-forming mechanism and work-clamping means having a relative movement at the completion of the sewing to carry the parts from stitching to buttonhole-cutting position and to draw out a length of thread through the throat plate, a thread cutter for cutting the thread between the throat plate and the last stitch, means to actuate the thread cutter after the clamps are released, and means to separate the work from the cutter prior to the cutting of the thread.

12. In a buttonhole sewing machine, in combination, stitch-forming mechanism, means to produce a relative movement between the stitchforming mechanism and the work, a threadtrimming knife situated transversely to the line of stitching and which is placed between the thread to be trimmed and the work by such relative movement, said knife operating in close adjacency to the work, means to actuate the threadtrimming knife, and means to separate the work from said knife before the thread is cut.

13. In a buttonhole sewing machine, in combination, stitch-forming mechanism, work-clamping means, thread-trimming means normallyin contact with the under surface of the work, and.

means to produce a relative separating movement between the work and-the trimmingmeans just prior to trimming the thread.

14. In a buttonhole sewing machine, in combination, stitch-forming mechanism, work-clamping means which clamp the work during the sewing and which release the work at the end of the sewing, thread-trimming means in'contact with the under surface of the work during the sewing, and means to produce a relative separating movement between said thread-trimming means and the work after the sewim operation but before the threads are cut,

15. In a buttonhole sewing machine, in combination, stitch-forming mechanism, work-clamping means which clamp the work during the sewing and release the work at the end of the sewing, thread-trimming means in contact with the under surface of the work during the sewing, and means to separate the work from the thread trimming means after the clamps are released but before the thread is cut.

16. In a buttonhole sewing machine, in combination, stitch-forming mechanism, work-clamping means which clamp the work during the sewing of the buttonhole and which release the work at the end of the sewing, said work-clamping means comprising clamp plates, and clamping feet pivotaliy. mounted thereon, thread-cutting mechanism operating beneath and in close adjacency to the work, means to actuate the threadcutting mechanism after the clamps have released the work, and means operating subsequent to the release of the work but before the thread is cut to raise the work from the clamp plates.

JOSEPH H. PIKUL.