US1839305A - Buttonhole sewing machine - Google Patents

Description

Jan. 5, 1932. B. FISHER 1,839,305

BUTTONHOLE SEWING MACHINE Filed Oct. 2, 1930 5 Sheets-Sheet l Fig. 1.-

\nvenToT. Benjamin Fisher b ymal QMkM ATTys.

Jan. 5, 1932. B, FISHER 1,839,305

BUTTONHQLE SEWING" MACHINE Fil ed Oct. 2, 1950 s Sheets-Sheet 2 \nvenT'or. Benjamin Fisher ATTys.

Jan. 5, 1932. B. FISHER 1,839,305

BUTTONHOLE SEWING MACHINE I Filed 0ct. 2, 1950 5 Sheets-Sheet 3 \nvenTor.

Benjamin Fis her Patented Jan. 5, 1932 IT n1 S A-res PATEN oFFIice BENJAMIN FIsHEa, on swAMrscomr, MASSACHUSETTS nssienon T0 Tim" REEcn nu'rron HOLE MACHINE COMPANY, or BOSTON, MASSACHUSETTS, A oonronA'rIoN or. name BUTTONHOLE SEWING. MACHINE Application fiI'edOctober 2, 1930'. SerialNo. 485,961..

"This invention relates to huttonho-le sewing machines and particularly to that type of machine which is provided with means for spreading the work after it is clampedand before the buttonhol'e is cut and also with means for cutting the thread underneath the work at theend of the sewing operation. One type of threadcutterwhi'ch is-comr monly used in these buttonhole sewing machines comprises a swinging cutter member which during its thread-cuttin-g movement passes between the work and the work-supporting plate and which co-operateswith a fixed ledgerblade-situated beneath the work;

7 A buttonhole sewing mac'h inehaving a thread cutter of this type is illustrated in Connors Patent No. 1,542,764, dated June 16, 1925 In the sewing machine described in saidpatent the work is held by the two work-clamp ing elements each comprising an under'cl a mp plate. and an upper clamping member;

WVhen the machineis started in operation the upper clamping members are carried down against the work to'clan'ip the latter against the under clam-ping member's and then the two clamping elements are separated slightly from each other to spread the work or placeit und'ertension, this occurrin g before-the stitching is perf'ormed' on thebuttonhole and also before the buttonhole slit is out. w

In the sewing machine such as shown in said patent the ledger blade with which the swinging threadcuttingknife co-operates is fixed to the work-supporting plate and is situated directly beneath the workfi'Withi this construction the spreading of the workclamping members by which the work is placed under tension drags the worl'r over the cutting edge of the ledgerblade. This has been foundto be detrimental when op-' 'erating on some classes of work because of the danger that the work will be marredi by its slidin-g'movement over the: fixediledger blade. I

The object of my presentfinvention is to provide a novel; thread-cutting arrangement of theabove type which is so constructed that the ledger blade iscarniedby one-of the work clamping elements and partakes of the move:-

ment of said element when the clampingele ments are spread.- The advantage of this is that there is no relative movement between the work and the ledger blade during the spreading of the clamp and hence the spread.-

ing action of the work-clamping elements can be accomplished without danger'of injfur ing or marring the work. in anyway.

order to give an understanding of the invention Ihave illustrated in the. drawings a selected embodiment thereof which; will nowbe described after which the novelafeatu-res will be pointed out in the appended claims;

Fig. 1 is a side view of a buttonhole sewingmachine embodying my invention;

Fig: 2 is a top plan View of the worlcsupporting plate showing the. workrclampin elements mounted thereon;

- ii ig; 3 isa section on the line Eig; 2; Fig.v 4 is a section on the line l-4i 2:; Fig; 5 is a fragmentary under side-view of thework-holding member; I

Fig. 6 is a section on the line 6-6,;.Eig: 2".

' In the sewing machine 1 indicates generally the bed frameon which is mounteditheworksup-porting plate 2 that carries the workc'lampingelements and 3isthe head portion of the sewing machine in which is mounted the vertical reciprocating needle bar 4 carry.- ing the upper needle 5. Grepresentsthebuttonhole cutter by which the buttonholeslitl'is cut, this being mounted on a: cutter leverf'? pivoted to the head at '8' and being" actuated in usual manner from the main cam 79: by which the operations. of the sewing machine are controlled; i 7

The work-holding means hereinillustrated is, in its main features, similar to. that now commonly used and also to that shown i n: the above-mentioned patent.

This work-holding means comprises: two a clampingelements, each of which includesiin its constructionan under clamping member 9 in -the; form of a plate havinga roughened I surface and an upper clamping memberil'O carried by 'aficlamp arm 11. Theclamp. arms II are pivot'allyzmount'ed to enable the-upper clamps 1O to move toward and fromsthezwork.

Each clamp arm is secured at its rear endi to work-holding means a block 12 which is pivotally mounted on a statonary shaft 13 that is carried by the work plate 2.

The clamps are closed onto the work when the sewing machine is started by the usual clamp-closing mechanism which is actuated by the cam surface 14 formed on the main cam 79. This clamp-closing mechanism comprises the usual lever 15 pivoted at 16 and which is given its downward clamp-closing movement b the engagement of the cam 14 with a roll 1 carried by the lever, said lever normally being held in elevated position by the spring 18. Secured to the end of the lever is a latch member 19 which is adapted to engage a pin 20 on an arm 21 rigid with the rock shaft 22 that is mounted in a supporting bracket 23. The rock shaft carries a cam 24; which is adapted to engage an arm 25 loosely mounted on the stationary shaft 13 and said arm abuts against a pin 26 carried by an arm 27 rigid with one ofthe blocks 12 so that when the lever 15 is depressed the rock shaft 22 will be turned and through the cam 24 and arms 25 and 27 the left hand block Fig. 2 will be turned to move the corresponding work clamp downwardly against the'work.

The two blocks 12 are interlocked so that the depression of one will also cause the depression of the other. This mechanism for closing the clamps is such as is commonly found in buttonhole sewing machines of this type and forms no part of my present invention.

These sewing machines are also provided with means for spreading the work-clamping elements after the work is clamped in order to place the work under tension while the buttonhole stitch is being performed and the buttonhole is being cut. i

- The spreading of the work-clamping elements is accomplishedby a spreading member 28 which engages the cam surfaces 69 formed on the under side of the blocks 12 during the relative movement between the and stitch-forming mechanism by which the parts are carried from buttonhole cutting to stitching. position and which occurs before the stitching operation commences. During this clamp spreading movement the blocks 12 have a sliding movement away from each other as shown by the full and dotted line position Fig. 2. The springs 29 tend normally to hold the work-clamping elements in the position shown in Fig. r

The machine herein shown also comprises thread-cutting mechanism by which the thread is 'cut beneath the work at the end of the sewing operation. This cutting mech- .ting edge 33 which'co-operates with theedge The swinging movement of the member 31 is secured by any suitable or usual mechanism and it occurs after the work is unclamped.

At the end of the sewing operation when the work clamps 10 are raised the thread extending from the under side of the work passes down through the opening 35 and as the cutter member 31 is moved to the right Fig. 2 beneath the work such threads are caught between the concave cutting edge 33 of the cutter and the ledger blade 30 and are severed.

The parts thus far described are such as may be found in buttonhole sewing machines of this general type and form no'part of my present invention.

As stated above in prior machines the ledger blade 30 has been mounted fixedly on the work-supporting plate 2. With this construction when the work clamps 10 are clamped against the work the latter will be pressed against the ledger blade and when the clamps are spread there is a tendency to drag the work over the stationary ledger blade with the result that the work is sometimes marred.

In mypresent invention I provide a construction wherein this ledger blade 30 is secured to one of the clamp plates 9 so that when the clamps are spread the ledger blade moves with the clamp and there is no rela tive moment between the work and the ledger blade.

The right hand clamp plate 9 in Fig. 2 is shown as formed with an extension 36 and the ledger blade 30 is provided with a shank portion 37 which overlies the forward end of the, extension 36 and which is secured thereto by suitable screws 38. The shank 37 of the ledger blade is shown as having slots 39 through which the screws pass thus providing for a lateral adjustment .of the ledger blade. Since the ledger blade is fixedly secured to one of the plates 9 and thus fixedly secured to one of the clamp elements said ledger blade will move with the clamping elements when the clamps are spread. This is illustrated in Fig. 3 wherein the full lines show the work clamps .10 in raised position and closed together with the ledger blade 30 in the corresponding position. After the clamps have been closed onto the work w then the clamps arespread asshown by dotted lines Fig. 3 and the spreading movement of the right hand block in Fig. 2 is conveyed to .the extension 36 and thus to the ledger blade 30 so that said blade moves with the corresponding upper clamp 10.

I claim. 7

1. In a buttonhole sewing machine, the combination with a work-supporting plate, of two work-clampingxelements carried 7 thereby each comprisingan under clamping 34, of the ledger blade torcutthe thread. plate and an upper clamping member, means .130

for closing the upper clamping members onto the under clamping plates, means formoving the clamping elements relative to the work-supporting plate and to each other to spread them, and a thread cutter comprising two cutting members, one of which is carried by one of the clamping plates.

2. In a buttonhole sewing machine, the combination with a work-supporting plate, of two work-clamping elements carried by said plate and each comprising an under clamping plate separate from the worksupporting plate and an upper clamping member, means for closing the upper clamping members onto the under clamping plates, means for spreading the clamping elements, and a thread cutter comprising a ledger blade carried by one of the under clamping plates, and a movable cutting member 00- operating with the ledger blade. 3. In a buttonhole sewing machine, the. combination with a work-supporting plate, of two work-clamping elements carried thereby, each clamping element comprising an under clamping plateseparate from the work-supporting plate and an upper clamping member, means for closing the upper clamping members onto the under clamping plates, means for spreading the clamping elements, and a threadcutter comprising a ledger blade carried by and moving with one of the under clamping plates, and a cutting element pivotally mounted to the work-supporting plate. In testimony whereof I have signed my name to this specification.

BENJAMIN FISHER.

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