US1234258A - Thread cutting and holding device for sewing-machines. - Google Patents

Description

W. L. BARRON.

THREAD CUTTING AND HOLDING DEVICE FOR SEWING MACHINES.

APPLICATION FILED SEPT. 6. 1913.

Patented July 24, 1917.

2 SHE ETSSHEET I.

WITNESSES:

W. L. BARRON. THREAD CUTTING AND HOLDING DEVICE FOR SEWING MACHINES.

APPLICATION FILED SEPT. 6. 1913.

Patented July 24, 1917.

2 SHEETSSHEET 2.

an. o.

WILLIAM LUTHER. BAERUN, OF NEW YORK, N. Y., ASSIGNOR TO THE SINGER. MANU- FACTURING- COMJPANY, A CORPORATION OF NEW JERSEY.

THREAD CUTTING AND HOLDING: DEVICE FOR SEWING-MAUHINES.

asagna.

Specification of Letters Patent.

0 application filed September 6, 1913. terial N0. teases.

To all whom it may concern.

Be it known that I, WILLIAM L. BARRON, a citizen of the United States, residing at New York, in the county of New York and State of New York, have invented certain new and useful Improvements in Thread hitting and Holding Devices for Sewing- Machines, of which the following is a speclfication, reference being had therein to the accompanying drawings;

My invention relates to automatic devices for two-thread sewing machines, adapted to sever the threads at the completion of a stitching operation and to nip or hold the ends of the needle thread and shuttle thread during the formation of the first of anew group of stitches to insure proper interlocking of said threads. Such devices are illustrated in the patent to Gatchell, No. 798,130, of August29, 1905, and in my application for patent filed February 7, 1913; Serial.

No. 746,696. The object of thepresentinvention is to improve the aforesaid devices and particularly the means :tor'nipping the shuttle thread.

In the present instance, the invention is applied to a Singer lock-stitch machine for sewing on buttons. The cutting and nipping elements include a tapered shuttlethread blade and a tapered needle-thread blade, a shuttle thread nipping finger and a needle thread drawing hook-all carried by a carrying arm pivoted to the under side of the throat-plate of the sewing machine. The carrying arm has a sector gear which meshes with a cam-actuated rack, and said cam, in conjunction with a stop-motion clevice, serves to impart positioning, cutting and nipping-movements to the elements.

The needle thread drawing hook is given its initial operative movement when the machine is started to form a group of stitches. The passage of the shuttle through the needle-thread loop first presented, draws the loose end of the thread down through the needle-hole; and the movement of the drawing hook serves to carry the loose thread into engagement with two membersv supported by the throat-plate, whereby the first member, a clamping jaw, nips the needlethread and the second member, a knifeedged notched plate, severs its loose end. A cam surface on the hook holds the springretracted clamping jaw against the thread until two ormore stitches are formed, when a second movement of the hook releases the tuated rack causes a forward movement of the carrier-arm whereby the lower threadis seized by the shuttle-thread blade, the

needle-thread blade being moved close to the Patented July tat, 119M.

needle-hole. The'needle descends, and, as

it rises, a second movement of the carrying arm causes the seizure of the needle thread loop by its blade, whereupon the final or thread-severing movement of the blades is effected, the rack and carrying arm being given a quick movement by a stop-motion lever, when the latter is operated to stop the machine.

In devices of the present type the shuttlethread when left loose at the commencement of a new group of stitches will frequently draw through one or more of the needlethread loops. To obviate this difliculty the present invention provides simple and effective means to nip the shuttle thread be fore the cutting operation in such manner as to securely hold what would otherwise be the loose end of the thread. The present construction renders unnecessary the employment of a cam-plate and sliding or swinging hook which form the subject of the patent to Gatchell above referred to. Ihe means employed in the present invent1on comprise aspring nipping-finger car ried by the blade-carrying arm and so shaped and positioned with respect to the shuttle-thread blade that the movement of the latter is employed to nip the shuttle thread between the lower face of said blade and the nipping finger.

In the accompanying drawings, Figure 1 is a side view of a button sewing machine embodying the present invention. Fig. 2 is a bottom view of the same. Figs. 3 and 4: are bottom plan views of the thread-nipping and severing attachment with the parts in dili'erent positions. Fig. 5 is a perspective view of the attachment with the parts in position after the release of the needle thread and shortly after the commencement of a stitching operation. Figs. 6 and 7 are sections of Fig. 3 at lines 66 and 77, respectively. Fig. 8 is a perspective View of the shuttle-thread blade and nipping finger showing the position of the shuttle-thread immediately prior to the severing thereof. Fig. 9 is a perspective view of the needle thread clamp and part of the needle-throat.

In the present instance the invention is applied to a Singer lock-stitch machine for sewing on buttons. As shown, the machine comprlses the standard 1, overhanging arm 2 and head 3, the latter supporting a vertically reciprocating needle-bar operated from the driving shaft 4. An oscillating shuttle is fitted withinthe shuttle race 5 supported'below the bed-plate 6, said shuttle idly attached sto -motion cam 11. "Pivot ally mounted at its lower end in a pro ection ,12 "from the standard is a start and stop-motion lever 13 provided with a belt shifting arm 14 andwith spring-pressed plunger 15. The stop-motion lever 13 is spring-pressed toward its rearward or oper ative position, and is detained in its forward or inoperative position by a detentlever 16' which is. maintained normally in operative engagement with the upper portion of thestop lever by means of the spring V 17 in a well-known manner. The stop-lever '13 is so mounted within the projection 12 as to be capable of slight sidewise movement against the spring-pressed plunger-p1n'l8,

' shown in end view only in Fig.1.

' The thread-cutting and nipping elements are carried beneaththe throat plate of the.

machine as shown in Figs. 3, 4 and 5. -The shuttle-thread blade 19 and the needlethread blade 20 are fixed upon swinging arm 21 carrying sector-gear 22,. which gear is journaled upon a pin 23- within a bracket 24 ifastened by means of screw-stud 24 to the under side of the throat-plate 25. Rigidly secured to the arm 21 is a thread-drawing arm or hook 26 disposed adjacent the under side of the throat-plate and formed at its forward end with a barb 26 As shown in Figs. 3, 4 and 5 the under side of the throatplate is recessed at 27 to accommodate clamping jaw 28 pivoted at 29 and normally held out of engagement with fixed jaw 30 within recess 27 by spring 31.

Meshing with sector-gear 22 is a rack 32 formed upon a lateral arm attached to sliding bar 33 supported beneath the bed of the machine and havingnear its rearward end a block 34 formed with a lateral notch. This notchis entered by the contracted lower end of a lever 35'pivotally mounted upon ful crum-stud 36 carried by a bracket 37 supported by the bed-plate of the machine, said I lever being provided at its upper end with a roller-stud 38 entering cam-groove 39 in the face of rotary cam-wheel 40, the latter being mounted upon the standard 1. Camwheel 40'is provided with a worm-wheel 41 meshing with a worm 42 fixed upon the main-shaft 4. The block 34 has a rearward extension carryingaroller-stud 43 embraced reassess,

by the forked arm of a bellcrankslever 44 fulcrumed at 45 and having a second arm provided with a-spring-pressed pin 46 entering aslot 47 in the lower end of stoplever 13. The lever 35 and bellcrank-lever 44 .serv'e, through the connections above described, to impart operative movements to the thread-cuttingand nipping elements," as more fully described in patent to Horton, No. 807,676,0f December 19, 1905.

i y In Fig, 3 vtheparts are shown in the position they assume when the machine is started to form a group of stitches. When the needle descends, the loose end ofthe needlethread is above the work-plate, but the passage of the shuttlethrough the loop of needle-thread draws the said loose end down through the needle-hole. rises, cam-follower, 38 travels over the inclined cam section 48 thereby moving lever 35 and its connections with sector-gear 22 to impart an initial rotary movement to the latter.

' The movement of sector-gear 22 will swing thread-drawing arm or hook 26 so that its hook will cross the needle-hole .50

" thereby engaging the loose end of the needlethread and drawingthe latter to one sideas shown in Fig. 7 and between the nipping aws 28 and 30. When the thread is so placed, a cam surface 26 formed on the thread-drawing arm or. book will engage .wheel. The hook 26 maintains its position (Fig. 4) to hold the clamp closed until two As the take-up or more stitches are formed, whereupon follower 32 leaves the dwell of the cam and reaches the inclined section 51 of the'cam groove. At this point the hook is given a second movement which carries the parts to the position shown in Fig. 5, the needlethread being released by the retraction oil clamp-jaw 28.

The parts are held in the position shown in Fig. 5 by dwell 52 in the cam until the close of a stitching operation, when the follower leaves dwell 52 and reaches an inclined section of the cam-groove. At this point the carrying arm and blades 19 and 20 will be advanced sufficiently to enable blade 19 to engage the shuttle-thread. The blades will then have a short period of rest while the follower is on a short dwell and will then moveso that, on the next descent of the needle, blade 20 will engage the nee- 1 dle-thread loop, and the two threads will be aeaeaa severed by the overthrow of the stop -lever at a point when follower 38 reaches a dwell section in the cam. That is to say, the blades 19 and 20 will be given a quick movement to their extremeforward position to sever the thread and will then be restored to the initial position shown in Fig. 3, as fully described in the patent to Horton above referred to.

A description will now be given of the means for nipping the lower or shuttle thread to which the present invention more particularly relates, the foregoing tion of the elements used in connection with said nipping means being necessary to a complete understanding of the invention.

Mounted upon carrying arm 21 and fastened thereto by means of screw 57 and pin 58 is the shank 59 of a spring nipping finger 60 which is held against the lower face of shuttle-thread blade 19 and which, at its outer end, is depressed and ofi'set from the edge of said blade. When the shuttle thread is seized by blade 19 in the movement of the parts from the position shown in Fig. 5 to the position shown in Fig. 4:, said thread is drawn over the tapering point of the blade until that portion leading to the shuttle passes between the blade and the offset point of spring nipping-finger 60.

The succeeding movement of blade 19 to cutting position, as shown in Figs. 3 and 6, is utilized to draw the shuttle thread between the lower face of the blade and the upper spring-pressed face of the nipping finger. The thread leading from the shuttle is held firmly between the finger and the blade when the parts are given a quick forward cutting movement by the overthrow of the stoplever, as previously described, and likewise uring a corresponding return movement of the parts to the initial position shown in Fig. 3. The shuttle-thread'is held by the nipping elements during the movement of the parts to the position shown in F 4, which effects the nipping of the needlethread and the severing of its loose end, and until several stitches of a new group are formed, the feeding of the work above the throat-plate serving to withdraw the shuttle thread from the nipping finger as will be understood without further expianation.

Having thus set forth the nature of the invention, what I claim herein is 1. In a sewing machine, the combination with stitch-forming devices, of a movable thread-cutter for severing the thread, and means for nipping the thread before a thread cutting operation comprising a nipdescripping finger carried by and cooperating with said thread-cutter in nipping the thread between itself and the adjacent face of the thread-cutter.

2. In a sewing machine, the combination with stitch-forming devices and av movable thread-cutter for severing the thread, of means for nipping the thread before a thread cutting operation comprising a spring nipping finger moving with said thread-cutter and pressed toward one face thereof against which it is adapted to grip the thread.

3. In a sewing machine, the combination with stitch-forming devices of a movable thread-cutter for severing the thread, a spring nipping finger sustained in fixed position relatively to said thread-cutter, and means including said thread-cutter for guid ing the thread between its face and the nipping finger before the thread cutting operation.

4:. In a sewing machine, the combination with stitch-forming devices and a movable thread-cutter for severing the thread, of a swinging support for said thread-cutter, and a nipping finger carried by said swinging support and spring-pressed against one face of said thread-cutter, the outer end of said finger being bent from the face of the thread-cutter and offset to form a threadguide.

5. In a lock-stitch sewing machine having a needle and a shuttle and making a predetermined number of stitches, means for nipping and trimming the beginning end of the needle-thread at the start of the cycle of operations, means for cutting the finishing ends of the needleand shuttle-threads, and means for nipping the shuttle-thread toward the end of a cycle of operations, said lastnamed means being movable with the means for cutting a finishing end of thread.

6. In a lock-stitch sewing machine having a needle and a shuttle and making a predetermined number of stitches, means for cutting the finishing ends of the needleand shuttle-threads, and means for nipping the shuttle-thread toward the end of a cycle of operations, said last-named means being movable with the means for cutting a finishing end of thread.

In testimony whereof, I have signed my name to this specification, in the presence of two subscribing witnesses.

WILLIAM LUTHER BARRON.

Witnesses:

Grim L. TERNA, W. LEE HELMS.

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