US1927950A

US1927950A - Thread trimmer for buttonhole sewing machines

Info

Publication number: US1927950A
Application number: US585073A
Authority: US
Inventors: Joseph H Pikul
Original assignee: Reece Button Hole Machine Co
Current assignee: Reece Button Hole Machine Co
Priority date: 1932-01-06
Filing date: 1932-01-06
Publication date: 1933-09-26
Anticipated expiration: 1950-09-26

Description

Sept. 26, 1933. .y 1 H, P|KUL 1,927,950

THREAD TRIMMER FOR BUTTONHOLE SEWING MACHINES Filed Jan. 6, 1932 5 SheetS-Sheet l Figi lrwenor. doseph H. PKUl Sept. 26, 1933. 1 H P|KU| 1,927,950

THREAD TRIMMER FOR BUTTONHOLE SEWING MACHINES Filed Jan. 6, 1932 v 5 Sheets-Sheet 2 Fig@ 4d 'as so 28 se l n e n To T. Joseph H. Pi Kul Sept. 26, 1933. J, plKUL 1,927,950

THREAD TRIMMER FOR BUTTONHOLE SEWING MACHINES Filed Jan. 6, 1952 5 Sheets-Sheet 3 Sept. 26, 1933. J, P|KUL 1,927,950

THREAD TRIMMER FOR BUTTONHOLE SEWING MACHINES Filed Jan. 6, 1932 5 Sheets-Sheet 4 Figli lnven'o'. Joseph H. PKUl bymaaMk/@M Sept. 26, 1933. J. H. PIKUL.

THREAD TRIMMER FOR BUTTONHOLE SEWING MACHINES 5 Sheets-Sheet 5 Filed Jan. 6, 1952 Fglfs lnvenl'o'r. Ljoseph H. Pi Ku bymmy M AX Tys.

Patented Sept. 26, 1933 UNITED STATES 'PAT Josephv H. Pikul, Troy, N. Y., assigner tov'lfhev Reece Button Hole Machine Company, Boston,

Mass., a corporation Application January 6,

19 Claims.

This invention relates to thread-trimming devices for buttonhole sewing machines by which the under thread and the stay cord, if one is used, are cut close to the work at the completion of the buttonhole, and it relates particularly to that class of thread-cutting devices in which the thread is cut after the work clamps have been opened.

An object of the invention is to provide a thread trimmer of this type which is relatively simple in its construction and which will operate to trim the thread close to the work even though the Work is not held by the operator, and which will also operate to as effectively trim the thread when the sewing is being done on slazy fabric as when the buttonhole is being sewed in a thicker and relatively llrm fabric.

In carrying out my invention I propose to employ a thread-cutting mechanism whose upper surface is substantially flush with the work-supporting surface of the Work-holding means. I also propose to employ a thread-cutting mechanism including a cutting member, the cutting edge of which lies close to the surface of the work and across which the thread is extended after the sewing is finished.

In the construction herein shown the threadcutting mechanism includes a thread-cutting member which forms part of the work-supporting surface against which the work is clamped by the work clamps so that during the sewing on the buttonhole said thread-cutting member forms part of the Work-clamping means. The upper surface of such cutting member is thus flush with the Work-supporting surface of the work-clamping means.

After the sewing on the buttonhole has been completed and the clamps have been opened the thread-cutting member is given its operative thread-cutting movement by which the under n thread and stay cord are cut close to the Work.

Buttonhole sewing machines are usually constructed so that after the sewing on the buttonhole has been completed the stitch-forming mechanism and work-holding means have a relative movement to carry the parts from stitching to buttonhole-cutting position and during such relative movement a length of under thread and stay cord is drawn out through the sewing opening of the throat plate, which length extends at an angle to the work.

In one embodiment of my invention the threadcutting mechanism is provided with a cutting blade having a cutting edge which extends normally in a direction transverse to said relative ofk Maine Y n 193.2. serial Ne. 585,073v

(c1. i12-252) l I y v movement, seid blade being 'sol positionedi that at the end of the relative movement the blade will be positioned between the throat plate and the work and the thread leading from the Work ENT .OFFICE 7 to the throat plate `will be drawn across said cutting edge. e

After the parts have been thuscarried into buttonhole-cutting position and the clamps have been released the thread `trimmer is actuated to trim the thread and because of the fact that the thread is Adrawn acrossthe cutting edge of hole sewing machine embodying my improvements; I

- Fig. 2 is a top plan view of the work-holding means with part broken out and illustrating one form of the thread cutter; e

' Fig. 3 is a section on the line 3 3, Fig. 2;

Fig. 4 is a perspective view of the thread-cutting member which forms part of the work-supporting surface;

Fig. 5 is a view of the element which co-operates with the thread-cutting member shown in Fig. 4;

Fig. 6 is an under side View of the clamp plate shown in Fig. 2; Y

Fig. 7 is a plan view of the turret with the loopers and other vmechanism omitted but showing the means by which the rotation of theturret actuates the thread cutter;

Fig. 8 is a section on the line 8-8, Fig. 2;

Fig.9 is a View of the thread trimmer showing its manner of operation;

Fig. 10 is a fragmentary sectional view showing the position of theparts just before the thread trimmer is actuated.

Fig. 11 is e view similar to Fig. l2 but showing showing the means for operating the thread cutter illustrated in Fig. 11. v

The sewing machine shown in Fig. 11 is of that type which comprises a bed frame 1 carrying the work-holding means by which the work 2 is heldv during the sewing operation, anda-lso the stitch frame 3 mounted on the bed 1 and carrying the stitch-forming mechanism. The stitch- .forming mechanism comprises the usual needle 4 operating from above the work and mounted in a reciprocating needle bar 5 and under thread mechanism Vwhich may conveniently be in the form of oscillating loopers andlooper spreaders (not shown) that are carried by a turret 6 rotatively mounted in the portion 7 of the stitch frame 3 which is located below the bed frame 1 and provided with the usualthroat plate 27.

The work-holding means comprises work-supporting surfaces situated on opposite sides of the buttonhole slit and workw'clampsv for clamping the work against thework-supporting surfaces. The Vwork-supporting surfaces are carried by

clamp plates

8 and 9 Whichform between them an opening 26 Ithrough which the needle operates. The work clamps by which the work is clamped against the work-supporting surfaces are indicated at 10 and 11 and said clamps are carried as usual by the arms 12 which are pivotally mounted'on the

clamp plates

8 and 9.

The work-supporting surface on the clamp plate 8 which is situated at one side of thevbuttonhole slit andagainst which the work clamp 10 clamps the work is constituted by the matrmember 13 `which has the usual roughened surface.

" The work-supporting surface on the other side of the buttonhole slit which is rcarried by the 'clamp plate 9, and against which the work clamp 11 clamps the work, is formed partially by a mat I member 14, and partially by a thread-cutting horizontal plane or about a vertical axis.

member, the upper surface of which is flush with the work-supporting surface 14.- In the construction shown in Fig'. 2 this threadcutting member is indicated at 15 and it is pivotally mounted in the clamp plate 9 vto swing in a For this purpose the member 15 is mounted to turn on a stud 16 which is mounted in the clamp `plate 9. The upper surface of the thread-cutting member 1511s flush with the surface of the mat member 14 and the end of'said member which is adjacent the mat member 14 underlies the work clamp 11 vas best seen in Fig. 2 wherein the complete shape of the'work clamp 11 is indicated in dottedrlines. f

The cutting member 15. is provided with a thread-cutting edge 17 which preferably has an inclined position with relation to the length of the buttonhole. The end edge 18 of the cutting member 15 is formed on an arc struck from the pivot 16 as a center and the adjacent edge 19 of the mat member 14 is lsimilarly curved.

When thev clamps 10, 11 are closed the'clamp v 10 will clamp the work against the mat 13 while the clamp 11 iwill clamp the work against both the mat 14 .and the end'of the cutting member 15.

This thread-cutting member 15, Ywhich thus forms part ofthe surface against which the work is clamped during the sewing operation and which thus constitutes a work-supporting cutting member; co-operates with another cutting'member 20 to effect the cutting of the thread. The member the cutter member 15 and the upper surface of the member 20.

' As will be understood by those vfamiliar with buttonhole sewing machines of this type the stitchorming mechanism and work-holding means have a relative movement after the sewing on the buttonhole has'been completed and the stitch-forming mechanism has come to rest withthe needle raised, such relative movement carrying the parts from stitching toy buttonhole-v cutting position. During this relative movementy under thread mechanism and during this fulk ther relative movement the increased strain which is put on theupper thread will break it as described in my co-pending application Serial Nc. 525,092, filedMarch 25,1931. This leaves the under thread and stay cord to be cut.`

rlhe cutting portion 23 and cutting edgev24 of the member 2) are so situated that during such relative movement the portion 23 is placed between the throat plate 27 ,and the work so that at the end of such relative movement the.por' tien 23 of the cutting member2 will be situated between the workvand the lengths land 71 of the under thread and stay cord which have been drawn through the throat plateas best seen in Fig. 10. During such movement also theunder thread and stayccrd Will' be drawnagains Vor across the cutting edge24 of the cutting memn ber 20 so that at this time these threads to be cut will be located between thetwo cutting' edges 17 and 24. v f

This operation of introducing the blade mem" ber between the throat plate and the workv and thus placing said memberbetween the work and the lengths 70 and 710i the under thread and stay cord which have been'drawn through the buttonhole and in a position so lthat said thread and stay cord will be drawn across the cutting edge ofthe cutting member is made possible because of the fact that said cutting edge extends -transversely to the direction of relative movement between the stitch-forming mechanismand Work-holding means by which the` partsk are carried from stitching to buttonhole-cutting position.

After the thread and stay cord have been placed across the cutting edge 24" the cutting members 15 and` 20 are actuated to cut the thread by being turned about their common Vpivot thereby closing the cutting edges together with a scissorsflike action. Before this Vis done, however, the werk clamps arev released. so that the cutting of the under thread and stay cord occurs while the work yis unclamped. v

InA the construction shown in Fig. 2 the threadvcutting movement involvesa movement of both the cutting edges 17 and 24, these edges moving toward each other and having ascissors-iike action. Since the work is resting on the two Vbladesor cutting members 15 and 2G and since the blade 20 is relatively thin the stay cord and under thread will be cut close `tothe work. Moreover, since eachcutting edge has a movement Vtoward the, other cutting edge there will be no tendency to displace thework. Any Yfrictionof one cuttingmember against the under surface of Vthe work tending to move it in' one direction is rec counteracted by the movement of the other cutting member against thework tending to move it in the opposite direction and hence the work will be held stationary and the threads will be properly cut even though the operator is not holding the work, it being understood that the Work is unclamped during the thread-cutting operation. Moreovenvsince both cutting

edges

17 and 24 are inclined to the center line of the buttonhcle the thread cutter will work equally well regardless of the length of the buttonhole.

In the construction shown in Fig. 2 I propose to make use of the turning motion of the turret 6 to give the

cutters

15 and 20 theirthread-cutting movement.

It will be understood by those familiar with buttonhole sewing machines of this type that the turret 6 makes a half revolution in sewing around the eye end of the buttonhole and after the sewing on the buttonhole has been completed and while the parts are moving, or after they have moved, from stitching to buttonholecutting position, the turret will have a. reverse rotation to bring it back to its normal position. The construction shown inFigs. 2 to 8 is such that this reverse rotation of the turret serves to actuate the

cutters

15 and 20.

The cutter element 15 has a tail portion 28 and the cutter element 20 has a complemental tail 29. When the cutter elements are assembled these

tails

28 and 29 are spaced from each other and situated between them is a cam member 30 which is fast on the upper end of a stud 31 that is rotatively mounted in the work clamp 9. This stud is shown as extending through the work clamp 9 and also through a plate 37 Which is situated underneath the clamp plate 9 and is secured thereto by a screw 38. The stud 31 is shown as having a collar 39 located between the clamp plate 9 and the plate 37, by which construction the stud will be held from vertical movement. This stud has an arm 32 projecting therefrom which is provided with a depending extension 33. The turret 6 has an arm 34 rigid therewith which extends radially beyond the turret and is provided With an upstanding dog portion 35. The arm 34 is so positioned on the turret that when the sewing on the buttonhole has been completed but before the turret begins its reverse rotative movement the upstanding dog 35 will have'a position closely adjacent the downturned extension 33 of the arm 32 as indicated in Figs. 7 and 8. When the reverse turning movement of the turret takes place in the direction of the arrow Fig. 7 the dog 35 will engage the down-turned end 33 of the arm 32 thereby swinging said arm and turning the'stud 31 and the cam member 30 as shown in Fig. 9. This turning movement of the cam member separates the

tails

28 and 29 thereby causing the cutting edges 17 and 24 to close together, which operation will cut the under thread and stay cord as above stated.

It will be noted from Fig. 9 that the cam 30 acts on the tail 29 of the cutting member 20 adjacent the end of the tail while it acts on the tail 28 of the cutting member 15 at a point relatively close to the axis of rotation. As a result the cutting member 15 will be given a greater turning movement than the cutting member 20 and hence while both cutting

edges

24 and 17 move toward each other yet during the entire movement of the cutting member 24 it will maintain a position intersecting the center line of the buttonhole and hence will be in-a. position to engage the under thread and staycord regardless` of the length of the button hole being sewe'd. Y

36 indicates a spring which acts on the tail members 28and 29 and tends normally to hold them in the position shown in Fig. 2. This spring serves to open the scissors cutter and to 4'restore it to normal position after the cutting operation. A40 indicatesr a cover plate which overlies and covers up the tail portions of the cutters and the spring 36. This cover plate has a recess 41 in one end which fits around the circular body portion 21 of the cutter member 20, said cover plate coming flush with the body portion. This cover plate is held in position by the screw 38above referred to.

The

blades

15 and 20 of the scissors-like cutting device may be made relatively vthin so that they take a small amount of room in a vertical direction and as the top surface of the cutting member 15 is flush with the top surface of the

mats

13 and 14 the cutter occupies very little room and does not interfere at all with the sewing operations.

In' the construction shown in Figs. 11 and 12 there is a single movable cutting element, thisr being indicated at 42. Said cutting element is shown as pivotally mounted on a stud 43 carried by the clamp plate 9 and the upper surface thereof is flush with the mat 14 and the end thereof constitutes part of the surface against which the work 2 is clamped by the work clamp 11. As shown in Fig. 11 the end of the cutting element 42 underlies the clamp member 11 so that when the latter is in lowered clamping position it clamps the work against the end of the cutter element 42 as well as against the mat 14. This cutting element 42 is provided with a cutting edge 44 which co-operates with the front edge 45 of a cover plate 46 to cut the thread and stay cord, the *edge acting as a ledger blade. In this embodiment the cutter v42 is given its operative thread-cutting movement by the turret-rotating means rather than directly by the turret.

The cutter member 42 extends beyond its pivotal mounting 43 as shown at 47 and said projecting end is provided with a stud 48 which depends through a slot 49 formed in the clamp plate 9. This stem is acted on by a spring 50 which normally tends to hold the cutter in its inoperative position shown in Fig.A 11 wherein it rests against the edge 51 of the mat 14. This stud 48 is adapted to be acted on by a nger 81 extending from a slidev 52 that is located beneath the bed frame 1 and is adapted to move transversely thereof. The slide is provided at one end with a slot 53 through which extends a pin or stud 54 secured to the bed frame 1 and the other end of the slide is pivotally connected to a lever 55 pivoted at 56 to the bed frame and having at its free end a dog member 57 adapted to be engaged by a nose 58 which is carried by the turret-rotating lever 59. Thislever 59 is such as is found in buttonhole sewing machines of this The parts are shown-in Fig. 1l inthe positionthey assume when the stitching on the buttonhole is completed, and when the parts are moved fromv stitching to buttonhole cutting position,

the throat plate 27 will be moved into the dotted line position and during this movement the plate i6 vwith its cutting edge 45 will be introduced between the Ithroat plate and the workand the underthread and staycord which` are drawn through Athe throat plate by'such movement will be laid across the edge i5.l At this time the levers fifi 59 are operated to give the turret its reverse movement Vand during vsuch movement the nose 58 engages the dog 5'? and swings the lever clockwise, Fig. `i3 thereby moving the 'slide 52y to the right which will cause the nger 81 to engage the stud `48 and thereby give the cut ter i2 its thread-cutting movement. Y

l During the swinging movement of the lever 59 vthe nose 58 will wipe by and become disengaged from the dog 57 Yand when this occurs the bar 52 :will be returned to its normal position bythe spring 58 while the spring 50 will return the knife to its normal inoperative position. f

In the construction illustrated in Fig. 11 the plate 45 is the member vwhich is introduced between the throat plate and the worlby the relative movement from stitching to buttonhole-cutting .25.

position and the edge 45 is theedge which stands transverse to such movement and around which the stay cord and under thread are laid, This plate i6 also serves as themeans for supporting i the worlrand preventing it from being pulled 3.0.

Y against both the stationary and movable por- 40,

tions of said workfsupporting surface, and'means operative after the clamps are released to move the movable portion of said surface thereby -to cut the thread beneath the Work. Y

2. In a buttonhole sewing machine, in'combination, work-holding means comprising a worksupporting surface Yand worlr` clamps for clamping the work against said surface, said worksupporting surface 'having a portion stationary relative to the work and another portion mova- ,50.

ble relative thereto and provided with a cutting edge, and means operative after the Yclamps are released to give the 'movable portion of said sur-r face an' operative movement to cut the thread beneath the Work.

3. In a buttonhole sewing machine, in combination, work-holding means comprising clamp plates having work-clamping mats, a thread-cutting member adjacent one end of one mat and having its upper surface flush with the worksupporting surface of the mat, work-clamping means operating to clamp the workr againstthe mats and thethread-cutting member, and means operative after the clamps are opened to give the Vthread-cutting membera movement to cut the 5.l In a buttonhole sewing machine of the type having stitch-forming mechanism including under thread mechanism and a turret on which theY kunder thread mechanism is mounted, the combi-` nationwth said stitch-forming mechanism and turret, of work-holding means,v a scissors-like thread cutting elementfor cutting the thread at the end of the sewing operation, and means foractuating the thread-cutting element by a rotary movement of the turret.

6'. In a buttonholeV sewing machine of the type having stitch-'forming mechanism including under thread mechanism and a rotary turret on which the under thread mechanism is mounted and Vwhich has a reverse rotation after the completion of the sewing operation, the combination with said turret, of work-holding means provided with a work-supporting surface, a pivoted thread-cutting member forming part vof such work-supporting surface, work-clamping means `to clamp the work against'the work-supporting surface including the thread-cutting member, and means roperated by the reverse rotation of the turret after theclamping means are released to actuate the thread-cutting member to cut the thread beneath the work.

7. In a buttonhole sewing machine of the type having A stitch-forming mechanism including under thread mechanism and a rotary turret on which the under thread mechanism is mounted and which has a reverse rotation after the completion ofthe sewing operation, the combination with said turret, of work-holding means provided with a work-supporting surface, a pair of pivotally-mounted thread-cutting members, one of which forms part of the Work-supporting surface, work-clamping means toclamp the work against said surface including said thread-cutting member, and means operated by the reverse turning movement of the turret to actuate ,the thread-cutting elements after the clamps have been released. v

8. A buttonhole sewing machine having a work-supporting surface against which the Work is clamped during the sewing operation, a pvoted cuttingblade forming part of such surface, workk clamps for clamping the work against said surface including said blade, said blade having a cutting edge extending at an angle to the centerline of the buttonhole, a co-operating cuttingblade also having a cutting edge at an angle to thecenter line of the buttonhole but extending across said center line, and means operative after the work clamps are opened to actuate the blades to cut the thread beneath the work.

9. In a buttonhole sewing machine, in combination, a work-supporting surface against which the work is clamped duringthe sewing operation, Work-clamping -means for clamping the Work against said work-supporting surface, a threadcutting member whose upper surface is substantially ilush with the work-supporting surface, and means operative after the clamps are released to actuate the cutter to cut the thread beneath the work.

10. In a buttonhole sewing machine, in combination, stitch-forming mechanism, work-holding means, said stitch-forming mechanism, and workholding means having a relative movement at the end of the sewing at the completion of which relative movement the thread leading to the source of supply extends away from the plane of the work and a thread cutter having a cutting vedge which lies close to the surface of the Work and across which the thread is extended at the end of such relative movement.

1l. In a buttonhole sewing machine, in combination, stitch-forming mechanism and workholding means having a relative movementl at the end of the sewing operation, a thread cutter having a cutting edge which normally extends transverse to such relative movement and across which the thread leading from the last stitch is laid by such relative movement.

12. In a buttonhole sewing machine, in combination, stitch-forming mechanism, Work-holding means, a throat plate through which the thread is led to the work, said stitch-forming mechanism and work-holding 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 having a cutting edge extending transverse to such relative movement and across which the thread drawn out from the throat plate is laid.

13. In a buttonhole sewing machine, in combination, stitch-forming mechanism, work-holding means, a throat plate through which thread is led to the work, said stitch-forming mechanism and work-holding 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 having a cutting edge extending transverse to such relative movement and across which the thread drawn out from the throat plate is laid, such relative movement placing the thread cutter between the throat plate and the work.

i 14. In a buttonhole sewing machine, the combination with stitch-forming mechanism, of means for trimming the thread and/ 0r stay cord consisting of two movable co-operating cutting elements situated substantially parallel with the plane of the work, and with one of such elements extending transversely to the line of the buttonhole stitching.

15. In a buttonhole sewing machine, the combination with stitch-forming mechanism, of

means forA producing a relative movementv between the stitch-forming mechanism and the work, and a thread-trimming knife having a cutting edge situated transversely to the line of stitching and which is placed between the thread and/ or cord to be trimmed and the Work by such relative movement.

16. In a buttonhole sewing machine, the combination with stitch-forming mechanism, of means for producing a relative movement between said stitch-forming mechanism and the work, a thread-trimming knife having a cutting edge extending transversely to the line of stitching, said knife being so positioned that it is placed between the work and the thread or cord to be trimmed by such relative movement.

17. In a buttonhole sewing machine, the combination with stitch-forming mechanism, of a trimming knife comprising a pair of blades having cutting edges, and means for actuating the blades, the locus of the intersection of the cutting edges of the blades as the latter are closed moving in a line substantially parallel to the plane of the work and transverse to the line of stitching.

18. In a buttonhole sewing machine, the combination with stitch-forming mechanism, Work-clamping means4 comprising clamp plates against which the work is clamped and two movable co-operating thread-trimming elements, one of which acts as a part of the work support, situated on top of the clamp plates.

19. In a buttonhole sewing machine, in combination, stitch-forming mechanism, work-holding means, said stitch-forming mechanism and work-holding means having a relative movement at the end of the sewing, at the completion of which relative movement the thread leading to the source of supply extends away from the plane of the work, and a thread cutter having a cutting edge situated substantially parallel to the plane of the work and which lies close to the surface of the work and across which the thread is extended at the end of such relative movement.

JOSEPH H. PIKUL.

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