US1843534A - Stop-motion device for sewing machines - Google Patents

Description

Feb. 2, 1932. E. B. ALLEN 1,843,534

STOP MOTION DEVICE FOR SEWING MACHINES Filed July 12, 1930 5 Sheets-Sheet l illlllllll lllllllflllllllll! dam/M1 Feb. 2, 1932. E. B. ALLEN STOP MOTION DEVICE FOR SEWING MACHINES Filed July 12. 1950 5 Sheets-Sheet 2 gwuentoz Edward flAlZerz Feb. 2, 1932. E. B. ALLEN STOP MOTION DEVICE FOR SEWING MACHINES 5 Sheets-Sheet 5 Filed July 12, 1930 duo emu Feb. 2, 1932. E. B. ALLEN 1,843,534

STOP M OTION DEVICE FOR SEWING MACHINES Filed July 12, 1950 5 Sheets-sheet 4 l J0 t 1 Edward flAJZeiz Feb. 2, 1 932. E. B. ALLEN 1,843,534

STOP MOTION DEVICE FOR SEWING MACHINES Filed July 12, 1950 5 Sh'eis Sheo 5 f w A l ,1

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i 52 -i y e 57 I 34 l J0 4 w .1? 11 Q l g 1 56 A 5 4 43 I L rw- 10 J 9 4542\X\ 50 a I 35)?56 if 5 14 J1! 13 13 gwoemio o Edward flullleiz Patented Feb. 2, iesz st sf Area? Free EDWARD B. ALLEN, or Nnwrown, oonnn'o'ricunnssienoa TO THE smennlivmnnracrumne COMPANY, or ELIZABETH, NEW JERsnY, A CORPORATION or NEW JERSEY Application filed July 12, 1930. erial No. 467,432."

This invention relates to stop-motion mechanism for sewing machines, more particularly of the type represented in the patent to Allenllo. 7 43,212, of Nov. 3, 1903, and has for an object to provide improved means for releasing or tripping the stop-motiondevice when the stop-cam bears a predetermined relation to the stop-plunger, so that the stopplunger will always initially engage the low point of the stop-cam without dragging over the inner face of the stop-cam or nickingthe' edge of the latter. I

The lnventlon consists 1111 116 devices, comblnations and arrangements of parts hereinafter described and claimed.

The several features of the invention and the advantages attained thereby will be readily understood by thoseskilled in the art from? the following descriptionof a preferred embodiment thereof taken in connection with the accompanying drawings, of which Fig. 1

is a side elevation of a Singer 71-Class but-- tonhole sewing machine embodylng the in-- vention. Fig. 2 is a fragmentary top plan View of the bracket-arm of the machine; Fig. 3 is a detail view of the stitch-gears of the machine. Fig.4; is a perspective view of the stop-cam element of the stop-motion device with which the machine is equipped. Fig.

- is a. bottom plan view of the rearward endthe stop-motion lever in running position throughout the sewlng perlod. Flg. 8 1s a section on the line 8-8, Fig.7. Fig. 9 is a View similar to Figs.- 5 and 7 at the time of the tripping of the stop-motion lever. Fig. is a section on the line 10-10,

Fig. .9. Fighll is a'view similar to Figs. 5, 7 and 9, but illustrat ng the resettmg of the latch initially operated upon by the feedwheel tripping point and Fig. 12 is a section on the line 12-12, Fig. 11. I V

In the preferred embodiment of the inven tion illustrated, the machine isconstructed with a frame including the bed 1, standard 2, overhanging bracket-arm 3 and head 4 carry-. ing the usual reciprocating and laterally vibrating needle 5 with which the complementa'ry shuttle 6 cooperates to form stitches.

There is journaled in the bracket-arm 3, the main-shaft 7 having the usual needle and shuttle driving connections, the latter including the crank 8 and .pitlnan 9 which opcrates the rocking-forked element 10 on thestationary shaft 11. The rocking element or fork lO embraces the block 12 on the crankpin 13 carried by the crank-arm 14 fixed to the shuttleedriving shaft :15-and oscillates the latter in the usual manner- The' 'machine embodies the usual workclamp 16 and feed-wheel 17 which moves it over the bed 1' to place the stitches around the buttonholee When the main-shaft 7 is running, the feed-wheel 17 has stepiby-step movements imparted to it by the usual pinand-star-wheelr drive 18 which is connected throughthe usual reduction or stitch-gears 19 to thefeed-wheel-shaft 20.

The main-shaft 7 carries at its rearward end the usual tight and loose belt-pulleys 21, 22',and a pinion 23 which meshes with a gear 24; of double its size, which gear is connected through the usual buffer-springs 25 to the stop-cam 26 which cooperates in the usual mannerwith the upwardly spring-pressed stop-plunger 27 carried by the tilting stopmotion lever 28 fulcrumed on trunnion-screws 29 and has rigid. with it a forwardly extending arm 30 towhich is connected at 31 a rod 32'extending downwardlythrough the bedl and apertured at 32 for connection by a chain tothe'usual starting treadle. The stop-motion lever 28 is held in full line'or running position, Fig. 1, by a latch-arm 33 fulcrumed at 34: below the bed 1 and pressed by the spring 35 into a notch 36 in the side ofthe rod 32. The stop-motion device, as above described; is constructed substantially in accordance with the disclosure of the Allen and Myers application, Serial No. 272,416, filed Apr. 24, 1928. In the machine illustrated, however, the stop-cam 26 is of duplex construction, having two diametrical- 1y opposed stop-notches 26 and two plunger depressing eccentric portions 26 having low points 26 and let-in inclines 26".

Unlike stop-motions of this type heretofore constructed, the latch 33 is not moved directly by a tripping point on the feed-wheel 17 to release the stop-motion rod 32, but is coupled by the action of a tripping point on the feed-wheel to a reciprocating member actuated by the main-shaft which subsequently and at a predetermined position of the stop-cam 26, moves the latch 33 to release the stop-motion rod 32. The timing is such that one or the other of the let-in inclines 26 and adjacent low point 26 is opposite the upper end of the plunger-rod 27,'as shown in Fig. 10, when the stop-motion lever 28 isreleased. Hence the initial engagement of the plunger 27 and stop-cam 26 will be a clean-cut one, with no danger of the upper end of the plunger 27 striking and nicking the edges or corners of the eccentric portions 26 of the cam.

Rigid with the hub of the rocking fork 10 is an eccentric 37 which is embraced by one end of a link 38 the opposite end of which is formed with a slot 39 slidably engaging a stud-pin 40 fixed to one of the bed legs 41. The link 38 is thus in constant reciprocation while the main-shaft 7 is running. Pivoted at 42 on the link38 is a latchtripper in the form of a catch 43 having a hook-shoulder 44 adapted, when released, to directly engage the latch 33 and move the latter to release the stop-motion rod 32. The spring 45 urges the catch 43 in a direction toward the latch 33.

During practically the entire portion of the sewing operation, the catch 43 is detained in an idly reciprocating position, Figs. 5 and 6, below the latch 33, by engagement of the tail 46 of the catch 43 with the latch 47 which is fulcrumed at 48 on the stationary frame-bracket 49 and yieldingly held by the spring 50 in contact with the stop 51 on the bracket 49. V

The link 38, being operated by the eccentric 37, performs one cycle of movement or one reciprocation per stitch-forming cycle and is definitely related to the stop-cam 26 so as to occupy the same position in its cycle relative to a given cyclical or angular position of the stop-cam 26.

There is adjustably mounted on the feedwheel 17 a tripping point 52 which, at the completion of the sewing operation, engages the arm 53 of the latch 47 and moves the latter to the position shown in Figs. 7 and 8, thereby releasing the catch 43 which springs into engagement with the latch 33 and moves the latter to release the stop-motion rod 32 within a period of one stitch-forming cycle or less, following the instant it is released for operation. This provision makes for permanent accuracy in the timing of the releaseof the stop-motion control lever 28 relative to the angular position of the stop-cam 26. Figs. 9 and 10 show the relative positions of the parts at the instant of release of the stopmotion lever 28 and it will be observed that at this instant the low point 26 and the letin incline 26 of the cam 26 are opposite the upper end of the stop-plunger 27 which is free to move cleanly into cooperative engagement with the plunger-depressing eccentric portion 26 following which it is projected upwardly into the stop-notch 26 and arrests the rotation of the main-shaft 7.

The time of release of the stop-motion rod 32 by the latch 33 is thus entirely independent of the particular ratio of stitch-gears 19 employed and is bound to occur at a fixed predetermined position in the revolution of the main-shaft 7 and hence in a fixed predetermined position of the stop-cam 26.

There is mounted on the stop-motion latchrod 32 a bracket 54 on which is pivoted a tooth 55 internally biased by a spring 55, Fig. 5. In the stopping position of the parts, the tooth 55 is disposed below a lateral extension 56 ofthe tail 46 of the catch 43, Figs. 9 and 10. When the stop-motion latch-rod 32 is released, it is moved upwardly by its spring 57, Fig. 1, to shift the stop-lever 28 to stopping or dotted line position. During this upward movement of the rod 32, the rounded upper edge of the tooth 55 engages the lateral extension 56 which first rocks the tooth 55 on its pivot in opposition to its spring 55 until the tooth, in passing the lateral extension 56, kicks the latter upwardly, Fig. 11, or to the right, Fig. 12, sufficiently to reset the catch 43 in its lowered or idle position, which it occupies when the machine comes to rest, Figs. 11 and 12; the tooth-spring 55 being strong enough to reset the catch 43 in the, upward movement of the tooth 55. When the machine is restarted by the operator in pulling down on the rod 32, the tooth 55, in passing the lateral extension 56, idly deflect-s the latter momentarily; the catch 43 immediately returning to the position shown in Figs. 11 and 12. The tooth 55 is yieldingly retained by its internal spring 55'. Fig. 5, in engagement with. the. stop 55", Fig. 8.

Having thus set forth the nature of the invention, what I claim herein is 1. A sewing machine having, in combination, a frame including a bed, stitch-forming mechanism including. a reciprocating needle and shuttle, shuttle-driving mechanism, a work-clamp, a feed-wheel below said bed and connections for moving said workclamp, a stop-motion device for controlling the period of operation of the stitch-forming mechanism, said stop-motion device includ-' ing a stop-cam, a tilting stop-motion lever shiftable between starting and stopping positions, a pull-rod connected to said stopmotion lever and extending downwardly below said bed, a latch adapted to engage said rod to hold the stop-motion lever in starting position, latch-tripping means below said bed and connected to said shuttle-driving mechanism and moving idly during the sewing operation, and means including a tripping-point on said feed-wheel for rendering said latch-tripping means effective when the sewing operation is completed.

2. In a sewing machine, a frame including a bed, stitch-forming mechanism includ ing a shuttle, a shuttle-driving shaft, a rocking element for actuating the shuttle-driving I shaft, a stop-motion device for the stitchforming mechanism, sa1d stop-motion device includmg a control rod extendlng downwardly through said bed, a latch engaging said rod, an eccentric connected to said rocking element, a reciprocating link actuated by said eccentric, a latch-tripping element carried by said link, means for holding said element out of engagement with said latch during the sewing operation, and means for shifting said holding means to release said element when the sewing operation is completed.

8. In a sewing machine, stitch-forming mechanism, a main-shaft, a stop-motion device therefor including a stop-cam having a low point followed by an eccentric'portion and stop-notch, a stop-plunger cooperating with said stop-cam, a spring-biased lever carrying said stop-plunger and movable under the influence of its spring transversely of the plane of sa1d cam from a running position in which said stop-plunger is out of range of said stop-cam to a stopping position in which said plunger is within range of said stop-cam, a single latch for detaining said lever in running positon from the time the machine is started until said lever is finally released for cooperation of said stop-plunger with said stop-cam, latch-tripping means running with the main-shaft and performing an idle cycle of movement for each stitch-forming cycle throughout the sewing period, and means operating at the'end of a sewing period to establish an operative connection between said latch-tripping means and said latch, said latch-tripping means being timed to trip said latch when the low point of said I cam is in position to receive said plunger.

In testimony whereof I have signed my I name to this specification.

EDWARD B. ALLEN.

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