US2376417A

US2376417A - Thread cutter

Info

Publication number: US2376417A
Application number: US540127A
Authority: US
Inventors: Chudner Joseph
Original assignee: Individual
Current assignee: Individual
Priority date: 1944-06-13
Filing date: 1944-06-13
Publication date: 1945-05-22
Anticipated expiration: 1962-05-22

Description

May 22, 1945- J; CHUDNER 2,376,417

THREAD CUTTER Filed June '13, 1944 5 Sheets-Shet 1 INVENTOR. L765 e p71/ er J. CHUDNER THREAD CUTTER May 22, 1945.

s Sheets-heet 2 Filed June 13, 1944 m E. M

mm n I 4 R MW Q & I. F. k 3. w I on m Y B vmy m .A

R m R ||1||i| an "$7 x u J an May 22, 1945. J. CHUDNER THREAD CUTTER 7 Filed June 13, 1944 3 Sheets-Sheet 5 NVENTOR. Jseph Chudner' ifnesses case the threads held for continuing anew the- Pat ented Qumran srA'ras PATENT: OFFICE a i useph chuaneai i yt. N. Y. Appl|cati4;nc.::::s13, (1:14.41,1:irl2a;2l;lo-540,127

This invention relates to athread cutting mechanism which may be incorporated advantageously in a sewing machine.

An object of the invention is the provision of a cutting mechanism of the indicated character for cutting both the. over thread from the spool and nism as characterized above not only capable of cutting two threads, but capable; of cutting the threads at points close to the sewing or stitching, or if desired beyond the same, to leave end portions of the threads on the work, and in either stitching or sewing operation.

A further object is the provision of a thread cutter for a sewing machine which releases the thread tensioning means of the machine prior to cutting the top thread to the needle so as to assure continual sewing.

With the foregoing, other objectsand benefits of the invention will appear when the following Fig. 4 is an enlarged end view of the needle bar and presser foot assembly.

Fig. 5 is an enlarged perspective view of parts ofthe top thread cutter applied to the presser foot, the latter being raised. a

a of the present in-. venti'on applied thereto. i

cutting members in action cutting the top and bottom threads.

Fig. 12 is a top plan view'of the under-part of the cloth plate together with parts of the bottom thread cutter.

i Fig. 13 is a longitudinal sectional view of parts of the bottom or under thread cutter in action.

pinching or gripping the thread while cutting it.

, machine-involves parts of the machine as fol- Fig. 6 is a-view partly in section andpartly in plan of the top thread cutter applied to the presser foot, the movable cutting member bein shown in its normal position, the section being taken on the line Hot Fig. 5.

' Fig.7 is a view similar to F18. 6, but showing the aforesaid cutting member in its retracted position.

Fig. 8 is an enlarged sectional view taken on the line H of Fig. 6.

Pig. 9 is a iragmentarylongitudihal sectional man u an enlarged sectionalview showingball 21 on its outer'end.

lows: bed in, arm ll, cloth\piate l2, presser toot ll, needle I, needle-bar I5, automatic top thread tension l8, and presser foot lifter The top or overthread from the spool carried by the pin on the arm II is cut by means which operates in conjunction with the presser foot l3. The presser foot is recessed, as at I8, and has a sole plate I! removably secured to close the recess at the bottom and to provide a cutting member'having a cutting edge 20. A movable cut--.

ting memher 2| is mounted on the presser foot in the recess l8 for pivotal or oscillatory move-- ment with respect to the cutting member 9. Ac-

cordin ly, as shown in Figs. 5-9, a pivot 22 on provide a cutting edge 25 below and behind the edge 23. An arm "extends radially irom the upper end of the pivot 22 and said arm 26 has a It is to be understood the cutting member 2| moves up and down with the presser foot I: and also pivots with respect thereto. The .cuting member 2| is only operated when the presser foot I! is in he down position. Normally, the cutting me r 2| is in the cutting position when the machineis sewing. The top thread 28 from the spool 29 passes through the eye of the needle H and extends downwardly between the toes or; they presser toot behind the cam surface 2| of the. cutting member 2|. As the cutting member 2| pivots to the retracted position the thread'2l is flexed by the camining action of the surface 24,

thread 28 into the recess l8, thereby'releasably pinching the thread 28 between the presser foot and the cutting member 2| and at the same time the edge 28' coacts with the edge 22 in a shearing action cutting the thread 28 at a point beyond the needle with the thread still passing through the'eye of the needle. The thread 28 is therefore severed close to the stitching or sewing and after the cutting operation the sewing may be continued anew without any subsequent manipulations.

In order to operate the cutting member 21 for the stated purposes, there is provided means presently to be described A lever 33 is fulcrumed, 0

turn, thereby causing the operation of the cutting member 2!. The upper end of the lever 3d carries a stud or pin 33. An arm 34 is fixedly clamped, as at 35, on the forward end of reciprocal rod 36. The arm 3 i depends form the rod 36 and its lower end has a slot 31 which receives the pin 33. Upon forward movement of the rod 36, the arm 33 through the intervention of the pin and slot connection 33-31 moves the lever 3b in one direction to retract the cutting member M. The aforesaid pin and slot connection enables raising of the presser foot I3 without upsetting the operative relationship of the counterparts. The rod 36 is supported for reciprocal movement by

bearing brackets

38 and 33, respectiv'ely, on the arm H. A cushion coil spring 40 3 surrounds the rod 36 and has one end bearing against a head 41 on the rod 38 and its other bearing against the bracket '39. A yoke lever 42 straddles the arm II, and is i'ulcruined thereon, as at 43. The head 41 of the rod 38 is connection '44--45. The fulcrum 43 extends transversely through the arm II and has a radially disposedrod 46 extending downwardly through the bed 10. A retractile coil spring 41 has one 49 end connected with the rod 46, as at 48, and its opposite end connected, as at 49, with a fixed stud 50 on the underside of the bed Ill. The control lever 42 has limited movement in opposite.

directions by stops 5| and 52, respectively, on the arm II. The lever 42 'is normallyin engagement with the stop 5| under the action of the

springs

40 and 41 with the cutting member 2| in the cutting position.

In order to prevent the mechanism from being operated when the presser foot is raised, means is provided which cooperates with the presser foot lifter l1. Said means consists of a shoulder or the like 53, in the present instance formed on the rod '38 by reason of a notch in the rod, as shown 5.",

most clearly in Fig. 5. When the lifter I1 is up for the purpose of holding the presser foot in the raised position, the shoulder 53 will encounter the lifter I1 and so prevent movement of the rod 38 and parts'connected therewith.

In orderto release the tension of the thread 28 when the presser foot I3 is down and at the time the thread is being pinched by the cutting mem 'ber 21 just. prior to the thread being cut, means is provided which operates in conjunction with 5 the thread tension I6. Said means in the present instance consists of a cam surface 54 on the rod 36, as shown in Figs. 3 and 5. The cam surface 34 coacts with a rod 55 incorporated in the tension 19 in such manner that, as therod 36 moves to cause the actuation of the cutter member 2|, the tension 16 will be operated to release the thread. Thus, it will be possible for the cutting member 2| to pull the thread 28 into the recess I! to pinch it against the pressure foot 13, subslot 14 and lug 19 enables sumcient th ea be Ject to the withdrawal of the thread upon the movement of the needle 14. Upon the return movement of the rod 36 to its normal position,

the thread 28 will be automatically placed under tension again.

In order to cut or sever the under or bottom thread 60 from the bobbin simultaneously with the cutting of the top thread 28, there are pro- .vided means, presently to be described, housed :14 and threads 28 and 6B in the usual operation 01 the machine. The part BI is undercut to provide an inclined surface at the hole 54 whose circular wall embodied by the part 61! provides a cutting edge 61. The part 62 has elongated guide grooves or recesses 68 and 69, respectively in the upper and lower surfaces shown most clearly in Figs. 12 and 13. An elongated steel cutting member 10 is arranged for sliding movement in the recess 58. The member W'has an upturned transverse cutting edge 11 on the springy forward end. and also has a longitudinal slot 12 to accommodate the feed surface 13. There is also a slot 14 in the rear end of the member 10 to provide

abutments

15 and 18 respectively. A motion transmission member and thread puller 11 consisting of an elongated piece of metal is arranged for sliding movement in the recess 69. This part 11 has a longitudinal slot 35 18 which accommodates the feed surface 13. An nected with the lever 42 by a pin and slot conupstanding lug 19 on the part 11 is received in the slot 14 to cooperate-with the abutments 15 84 is adjustably secured to the lever42, with respect to the fulcrum 43, by screws 86 and slots- 81, respectively, the screw 88 being on the lever 42 and the slots 81 being in the throw member 84.

' The member 84 and lever 42 move in unison and cause the operation of the bell-crank lever 81.

It will now be understood that when the lever 42 is pushed forwardly through the intervention of the member 84 and lever 8.1, the part 11 will be slid forwardly from its normal position in which the lug 19 is back away from the abutment 15 in contact with the abutment 16. The forward movement of the part 11 causes the-front end to pull thethread 60 from the bobbin to afford a certain amount of slack. As the part 11 continues to be moved forwardly the lug 19 encounters theabutment 15 causing the cutting member 1'0 to slide forwardly with the part 11.

the thread 60, and at. the same time cause the member '10 to pinch the thread till against the part 62 of the plate 12. When the lever 42 is released, it will'be returned by the

springs

40 and 41 against the stop 5|, after causing the reverse movement of the part 11 and the cutting.

member 10 in which the lug 19 encounters the abutment 18. The lost motion afforded by the the sewing anew.

pulled from the bobbin to assure continuance of It istherefore understood that the over thread 28 andthe under thread 60 may be cut simultaneously close to the sewing or stitching; that suflicient end portions of the threads remain for continuing the sewing anew; and that the presser foot may be raised and the threads pulled by hand to leave long ends on the work before cutting the threads subject to the lowering of the presser foot; that the needle must be raised prior to the thread cutting operation; and that the mechanism can not be operated while the presser foot is raised and thereby averting damage to parts of the mechanism.

I claim:

1. In a thread cutting mechanism for a sewing machine, the combination of a presser foot. thread cutting means operatively mounted on said presser foot, means including a. reciprocal rod for operating the cutting means, a presser root lifter, and means on said rod which cooperates with said lifter when the latter is in the up position to prevent the cutting means from being operated while the presser foot is raised.

2. In. a thread cutting mechanism for a sewing machine, the combination of thread tensioning means, thread cutting means, means to operate the cutting means including a reciprocal rod having a cam surface, and means operated by the cam surface to operate the tensioning means to release the tension on the thread prior to thread cutting action.

3. In a thread cutting mechanism for a sewing machine, cooperative cutting members one of which is fixed and the other one being slidable. a

thread pulling member mounted to slide with respect to said slidable cutting member, coactin means on the slidable cutting member and the thread pulling member whereby said thread pulling member may be caused to slide for a part of its travel with respect to the cutting member and then cause the cutting member to slide with the thread pulling member to perform the following functions, namely, to pull the thread to provide a take-up portion, then pinch said portion, and then sever the thread beyond the point where it is pinched, and means to slide said thread pulling member in opposite directions.

4. A thread cutting mechanism for a sewin machine comprising cooperative cutting mem bers one of which is movable and the other being fixed, and means to operate the movable cutting member, said means including a manually operable rocker on the arm of the machine, a slidable.

rod on said arm, levers on the presser foot of the machine, one of said levers being connected with the movable cutting member, the levers being cooperatively engaged, an arm on one end of said rod, a pin and slot connection between said arm and the other of said levers, and said rocker being pivotally connected with the other end of said rod, and a retractile spring acting on said rocker.

5. In a thread cutting mechanism for a sewing machine, the combination of a presser foot, cooperative cutting members on said presser foot, one of said cutting members being fixed and the other cutting member being movable, a control lever, and means to transmit motion from the control lever to the movable cutting member to operate it, said movable cutting member normally disposed in the cutting position at one side of the thread to be cut, and said movable cutting member being so constructed and shaped that it flexes the thread while moving from the cutting position to its retracted position and then carries the thread toward the fixed cutting member to be cut by the cooperative action of the cutting members as the movable cutting member moves into the cutting position.

6. In a thread cutting mechanism for a sewing machine; the combination of a presser foot, cooperative cutting members on said presser foot. one of said cutting members being fixed and the other cutting member being movable. a. control lever, and means to transmit motion from the control lever to the movable cutting member to operate it, said movable cutting member substantially crescent shape and .normally disposed at one side of the thread to be cut so that it flexes the thread while moving from the cutting position to its retracted position and then carries the thread toward the fixed cutting member to be cut by the cooperative action of the cutting members as themovable cutting member moves into the cutting position.

ate it, and a presser foot lifter which cooperates with said last means when said litter is in. the

up position to prevent the movement of said control lever.

8. In a thread cutting mechanism as set forth in claim 3, wherein the slidable cutting member consists of an elongated blade with a cutting edge on one end, and said. coacting means consists of spaced abutments on the slidable cutting member, and a lug on the thread pulling member disposed for movement between said abutments into and out of engagement therewith in response to the movement of the thread pulling member.

JOSEPH CHUDNER.