US2040260A

US2040260A - Buttonhole sewing machine

Info

Publication number: US2040260A
Application number: US567560A
Authority: US
Inventors: Michael J Kenny
Original assignee: Reece Button Hole Machine Co
Current assignee: Reece Button Hole Machine Co
Priority date: 1931-10-08
Filing date: 1931-10-08
Publication date: 1936-05-12
Anticipated expiration: 1953-05-12

Description

May 12, 1936'. .M. J. KENNY ,040,260-

BUTTONHLE SEWING MACHINE Original FiledOct. 8, 1931 '2 Sheets-Sheet 1 lnvenToT.

Michoe \J. Kenny AT Tys.

12, 1936. M. J. KENNY 2,040,260

v BUTTONHOLE SEWING MACHINE Original Filed Oct. 8, 1931 2 Sheets-sheet 2 Fig.2.

\nvenTor.

Michael a). Kenny ATTys.

Patented May 12, 1936 UNITED STATES PATENT OFFICE poration of Maine 101- to Hole Machine Company, Boston, Mass, a cor- The Reece Button Application October 8, 1931, Serial No. 567,560 Renewed November 9, 1933 4 Claims.

This invention relates to buttonhole sewing machines.

In buttonhole sewing machines the work in which the buttonhole is to be sewed is held in 5 work-holding means which comprises two clamp plates or mat members, one each side of the buttonhole slit, on which the work is supported, and two work clamps, one each side of the buttonhole slit, which serve to clamp the work against the mat members, and usually the edges of the clamp members and mat members are in vertical alignment.

In sewing the buttonhole the needle makes its thrusts alternately in the line of the buttonhole slit and through the goods at a distance back from the line of said slit. For convenience the needle thrusts through the line of the buttonhole slit will be referred to as the slit thrusts and those through the goods back from the slit as depth" thrusts.

stitches will appear on the back face of ghe'goods as short lengths of threads ex mding'from the" buttonhole slit to the H nts where, the needle made the depth thrusts?" Where the depth thrusts are relativelymeld's e to the buttonhole slit so that the lengths'"of the stitches appearing on the back face of the fabric are relatively short, the buttonhole is commonly referred to as one with a narrow bight, the term "bight referring to it the length of the stitches as they appear on the back face of the fabric. On the other hand, when the depth thrusts of the needle are through the work at a considerable distance back from the buttonhole slit so that the stitches as they appear on the back face of the fabric are of generous length the buttonhole is commonly referred to as sewed with a wide bight.

Where a buttonhole is sewed with a narrow bight, on buttonhole sewing machines as now manufactured it frequently happens that the needle holes which are made in the work during the formation of the depth stitches will be visible after the stitching is completed thereby producing on the back face of the fabric, and sometimes on the front face also,- a marking which represents the line of holes made by the depth thrusts of the needle. One reason for the production of this marking is because the workholding means is usually so adjustedthat the inner aligned edges of the work clamps and mat members are situated just, outside the line where the needle makes its depth thrusts so that each depth thrust of the needle comes close to the aligned edges of the work clamps and mat members.

When the buttonhole is completed the In sewing a buttonhole with a narrow bight these aligned edges are relatively close to the buttonhole slit and hence a correspondingly narrow portion or strip of the work immediately circumjacent the line of the buttonhole slit will be projecting beyond the work clamp and mat and the work is firmly held along the line just outside of the line of the depth thrusts and hence relatlvely close to the line of the buttonhole slit.

The needle of a buttonhole sewing machine is necessarily of greater diameter than the thread used in sewing the buttonhole and hence the hole which the needle makes in the work during,

the depth thrust will be larger than the thread. 7

Where a buttonhole with a narrow bight is bein sewed in fabrics having certain Characteristics the hole which the needle makes during its depth thrust will remain visible after the thread has been drawn through. One reason for this is because when the needle makes its depth thrust it crowds the threads of the fabric apart and where only a very narrow portion of the fabric is extending beyond the portion which is firmly clamped in the work holder, as is the case when a buttonhole with a narrow bight is being sewed, the displacement of the threads in said narrow portion occasioned by the depth thrust of the needle stretches the narrow edge of the fabric projecting beyond the portion which is clamped between the work clamp and mat beyond its ability to recover and produces a permanent rearrangement of the threads of the fabric which leaves a visible needle hole in the fabric. The visibility of the needle hole is augment ed by the tension which is applied to the thread in forming the depth stitch. When each depth stitch is tightened the tension on the thread applies a pulling strain to the work which tends to maintain the needlehole and thereby increase its permanent visibility.

This permanent marking of the fabric constitutes a disfigurement which it is desirable to avoid and it is one of the objects of my present inventionto provide a novel buttonhole machine construction which will permit of the sewing of a buttonhole with a narrow bight without producing the permanent markings along the edge of the buttonhole formed by the depth thrusts of the needle.

In accomplishing the above object, the mats and the work clamps are so constructed that the edge of the mat is situated further from the line of the buttonhole slit than the edge of the work clamp, in other words, the work clamps and mats have such a relative arrangement that the inner work-whichis.clampe ilgtween the mats and the work clamps. and this gerfious 'width of work In stitching a buttonhole the alternate thrusts of the needle 6 are in the line of. the slit !4 and the other thrusts are through the fabric at points l5 situated at a distance back from the slit l4, and as stated above, the needle thrusts through the slit It may conveniently be referred to as slit thrusts while those through the fabric at points [5 may be referred to as depth thrusts. The full line position of the needle in Fig. 3 is the position the needle occupies in making the slit thrust and the dotted line that which it occupies in making the depth thrust.

which projects beyond the mat is supported by Ti-ie-worln clamps I are usually o adjusted the relatively wide throat plate during the sewing operation. Such generous width of work provides sufiicient elasticity in the portion of the fabric through which the depth thrusts are made so that when the needle is withdrawn from the work the needle hole will be closed up. With the needle holes all closed up the line of marking which is referred to above and which is caused by the needle holes will be obviated and a buttonhole with a narrow bight can be made without producing this undesirable marking on the goods.

In order to give an understanding of the invention I have illustrated in the drawings a selected embodiment thereof which will now be described after which the novel features will be pointed out in the appended claims.

Fig. 1 is a side view of a portion of a buttonhole sewing machine embodying my invention;

Fig. 2 is a top plan view of the work-holding means, said figure also showing the throat plate carried by the turret;

Fig. 3 is a section on the line 33, Fig. 2 but s he throat plate and needle in the posim ring the sewing of the buttonhole' Fig. 4 is a view of a butfi'n'hh I The principal elements of the s t'vn chine herein illustrated are similar to those iisually found in buttonhole sewing machines. M

The work-holding means comprises pivoted work clamps I, one located each side of the line of buttonhole slit, which clamp the work 2 against the mat portions 3 of clamp plates 4 that are carried by the bed 5 of the sewing machine frame. The mat portions 3, one of which is situated each side of the buttonhole slit, are usually provided with a roughened work-receiving surface.

The stitch-forming mechanism includes the needle 6 carried by a vertically-reciprocating needle bar i and operating above the work and the usual under thread mechanism which is mounted on a rotary turret 8 situated beneath the work. The turret 8 also carries a throat plate 9 which is provided with a sewing opening I!) in which the needle 6 operates as it makes its penetrating thrust.

It will be understood, of course, that the stitchforming mechanism and work-holding means are capable of moving relative to each other to provide for the feeding movement necessary to form the stitches along the edges of the buttonhole. In the machine herein shown the stitch-forming mechanism is carried by a frame H which is mounted on the bed 5 and which may conveniently be referred to as the stitch frame. Said stitch frame and bed have a relative movement to provide for the necessary feeding movement above referred to.

The machine herein shown is also provided with the usual buttonhole cutter comprising two cutting elements l2 and I3 which co-operate to cut the buttonhole slit l4.

that the edges i5 thereof lie closely'a facent to the line in which the depth thrusts of the needle are made.

In accordance with the present invention I propose to make the mat members 3 so that their inner edges H are more widely spaced from each other and each is at a greater distance from the line of the buttonhole slit l4 than the inner edges is of the work clamps. In other words, instead of making the mats with the inner edges II in alignment with the edges N3 of the work clamp or closely adjacent the line in which the depth thrusts of the needle are made, said edges 5? of the mats are cut back a substantial distance from said line of depth thrusts as shown best in Fig. 3. As a result of this construction, the inner edges E5 of the work clamps overhang the edges ll of the mat and when the work clamps are in operative work-clamping position the portion of the work 2 which is firmly clamped between the work clamps and the mat will be the portion outside of the edges 1'! of the mats, the portion of the work between the edges ll of the mat and the line of the buttonhole slit being unclamped. Hence with this construction there is a zone of fabric of substantial width immediately circumjacent the buttonhole slit which is not subjected to the clamping action of the work hp lQer and the mats, which zone is wider than the zon mcluded between the buttonhole slit and the line of depth thrusts of the needle or, in other words, the zone which .is covered by the stitches E8 of the buttonhole.

The throat plate 9 is made with a work-supporting surface IQ of generous width. In fact, said. work supporting surface I9 is wider than the space between the edges 16 of the work clamps during the sewing operation with the result that the throat plate 9 underlies the inner edges of the work clamps. Preferably this throat plate will be made of a size to substantially fill the space between the edges I! of the mat portions.

While the throat plate underlies the work as shown in Fig. 3 yet the work is not clamped between the throat plate and the work clamps in the same way in which it is clamped between the work clamps and the mats 3 because during the sewing operation the throat plate moves underneath the work in the direction of the length of the buttonhole, as will be understood by those skilled in the art.

With this construction when the needle makes its depth thrust as shown by dotted lines in Fig. 3 such thrust is made at a point somewhat separated from the portion of the fabric which is firmly clamped between the work clamps and the mat members 3 and hence as the depth thrust is made the threads on all sides of the needle will be displaced slightly as the needle passes through the goods. When the needle is withdrawn from the goods the elasticity ofthe fabric in the relatively wide zone of unclamped fabric will cause the displaced threads to again assume their normal position with the result that the needle hole will be substantially closed up and will not be visible. Furthermore, where the above-described construction is employed the amount of unclamped work between the line where the clamping action takes place, to wit, the line of the inner edge I! of the lower work-clamping member 3, and the line where the depth thrusts l5 are made, will allow sufficient give or stretch when the pulling strain is applied to the thread to tighten the depth stitch so that the tension on the thread will not unduly enlarge the needle holes as frequently happens when the work clamps are constructed so that the work is clamped close to the line of depth thrusts.

The throat plate supports the work during the penetrating thrust and the overhanging portion of the work clamps prevents the work at the buttonhole slit from being lifted up when the needle is retracted. There will, therefore, be no undue stretching of the work while the needle is making its penetrating thrust which will tend to produce a permanent needle marking on the goods. The advancing or forward edge 20 of the throat plate is square and is situated at right angles to the direction of movement of the throat plate during the sewing operation. This is an advantage as it not only gives a larger work-supporting surface to the throat plate but provides a construction in which the movement of the throat plate against the under side of the work during the sewing operation is less likely to distort the unclamped portion of the goods circumjacent the buttonhole slit.

With this invention it is possible to sew a buttonhole with a very narrow bight, that is, to sew a buttonhole in which the depth thrusts of the needle are relatively close to'the buttonhole slit, without leaving any needle markings such as oc cur frequently in buttonholes sewed with a narrow bight in which the inner edges of the mat are situated close to the line of the depth thrusts of the needle.

I claim:

1. A buttonhole sewing machine comprising a needle operating above the work and adapted to make slit thrusts and depth thrusts through the work, work-holding means comprising means to clamp the work each side of the buttonhole slit while leaving an unclamped zone immediately circumjacent the buttonhole slit which is somewhat wider than the zone bounded by the depth thrusts of the needle and a throat plate situated beneath the work and supporting the unclamped portion thereof immediately circumjacent the buttonhole slit, which throat plate moves relative to the work as the sewing proceeds, the advancing end of the throat plate being situated substantially at right angles to the direction of movement.

2. A buttonhole sewing machine having stitchforming mechanism including a needle operating above the work and adapted to make alternate slit and depth thrusts through the work, workholding means comprising work-supporting mats, one each side of the buttonhole slit, on which the work rests and work clamps, one for each mat, for clamping the work against the mats, the inner edges of the mats being spaced further from the line of the buttonhole slit than the inner edges of the work clamps, whereby the work clamps overhang the inner edges of the mats, and a throat plate which moves beneath the work as the sewing proceeds, said throat plate having a wide work-supporting surface to underlie the overhanging portions of the work clamps and a square advancing end.

3. A buttonhole sewing machine having workholding means including work-supporting mat members, one each side of the buttonhole slit, and work clamps for clamping the work against said mat members, the inner edges of the mat members being more widely spaced from the line of the buttonhole slit than the inner edges of the c work clamps, whereby said work clamps overhang the inner edges of the mats, stitch-forming mechanism including a needle operating to make thrusts alternately in the line of the slit of the buttonhole and through the fabric at a point adjacent the edges of the work clamps but spaced from the edges of the mats, and a throat plate beneath the work having a relatively wide worksupporting surface which underlies the overhanging portion of the work clamps and also having a square advancing end. i

4. A buttonhole sewing machine having stitchforming mechanism including a needle, a throat plate beneath the work, said throat plate and work having a relative movement as the sewing proceeds, and the advancing side of the throat plate being straightand extending at right angles to the direction of relative movement, said throat plate having a sewing opening to receive the needle, work-supporting means on which the work rests, and clamping means to clamp the work against the supporting means, said clamping means overlying the throat plate.

MICHAEL J. KENNY.