US2340391A - Buttonhole sewing machine - Google Patents

Description

Feb. 1, 1944. F. A. LADD; JR

BUTTONHOLE SEWING MCHINE Filed Dec. 5, 1940 S/Sheets-Sheet l Feb. 1, 1944. E A, ADD, JR 4 2,340,391

BUTTONHOLE SEWING MACHINE Filed Deo. 5, 1940 5 sheets-sheetv 2 Feb- 1, 1944- F. A. LADD, JR,

BUTTONHOLE SEWING MACHINE 3 Sheets-Sheet 5 Filed Dec. 5, 1940 Patented Feb. 1, 1944 BUTTGNHOLE SEWING MACHINE Frederick A. Ladd, Jr., Arlington, Mass., assgnor to The Reece Button Hole Boston, Mass.,

Machine Company,

a corporation of Maine Application December 5, 1940, Serial No. 368,651

sclaims.

This invention relates to stop mechanismsl for buttonhole sewing machines and the like, andespecially to machines-and mechanisms of the type shown in United States Patents No. 367,063, July 23, 1887; No. 713,764, November 18, 1902; and'No. 1,669,912, May 1'5, 1928.

A buttonhole sewing machine of the type shown in said patents includes stitching mechanism and workholding means having a relative movement lengthwise of the buttonhcle, mechanism for prostitching mechanism. Said driving and stopping mechanism comprises a stitching shaft having a loose driving pulley thereon, a clutch dog normally tending to connect said shaft and pulley, and a clutch disengaging member, carried by said last-named portion of said rocker, which is moved into a position to be engaged by said dog, thereby disconnecting said shaft and pulley and stopping "o the former, when the rocker is moved into the position to start the rapid feed.

In such a machine it is, of course, desirable that, when the rapid feed isstarted at the completion of the stitching' operation, the stitching l 1 mechanism be stopped with the needle withdrawn from the work. The mechanism described in Patent No. 367,063 was such as to cause stopping of the stitching mechanism with the stitching shaft in a definite angular position in which the needle is withdrawn from the work, but it was possible for the rocker to move-into the clutch releasing position (i. e., into the position to start the rapidl feed) when the needleV was in the work, or at such a' time' that the clutch dog had just passed the clutch disengaging member, thereby permitting a further partial rotation of the stitching shaft, sufficient to cause the needle to make another stroke and therefore re-enter the work, after the rapid feed was started. To prevent this, the mechanism described in Patent No. 713,764 included a cam carried by thestitching shaft and enga-geable by the rocker, said cam being soshaped as to prevent movement' of the rocker int-o position to start therapid feed except a fly over.

when the needle was withdrawn from the work and'said shaft was in such an angular position that the clutch dog was approaching, or was in a position to engage, the disengaging member and had not completely passed the same. Even in this mechanism, however, it was possible for the cam to be in such an angular position when engaged by the rocker as to permit the rocker to move into the clutch-releasing, rapid-feed position just as the clutch dog was passing the disengaging member, so that the clutch dog would wipe by the disengaging member and cause the latter to rebound and produce what is termed a ily over. Accordingly, the mechanism described in Patent No. 1,669,912 included, in addition to the cam above referred to, a stop linger and a second cam on the stitching shaft for so controlling the stop finger as to cause the latter to hold the clutch disengaging member against movement into stopping position when the first-named cam was in the angular position which would permit The present invention has for its general object to improve and simplify the mechanism described in Patent No. 1,669,912 and to this end contemplates the elimination 0f the stop nger and second cam of the mechanism of said patent while providing mechanism which will as effectively prevent the possibility of a ily over.

The more particular objects of the invention, together with means whereby the latter may be carried into effect, will best be understood from the following description of a preferred embodiment thereof shown in the accompanying drawings, this, however, being illustrative merely, sincethe invention, as defined by the claims hereunto appended, may be otherwise embodied with- 'out departure from the spirit and scope thereof.

In said drawings:

Fig. 1 is a side elevation, partly broken away, of a buttonhole sewing machine embodying the invention.

Fig. 2 is a fragmentary top plan view, partly in section, of the stop mechanism and its controlling means.

Figs. 3, 4 and 5, are fragmentary side elevations, partly broken away, of said stop mechanism and controlling means, showing the parts in different positions.

Fig. 6 is a horizontal section taken substantially on the line 6 6, Fig. 1.

The invention is `herein shown as embodied in a buttonhole sewing machine of the type` illustrated in the above-mentioned Patent No. 1,669,912. Said machine comprises a bed frame ing shaft I4 journalled in the stitch frame andY having thereon a loose driving pulley I5 (Figs.

l and 2) which is periodically clutched thereto drive the same. The movement of the stitching frame on the bed frame is derived from amain cam I6 carried by said stitching frame and driven by a worm on a shaft I1 journalled in said frame. During the stitching operation the shaft I1 is driven at relatively slow speed, to produce a relatively slow feeding movement, by ratchet Ymechanism, generally indicated at I8, operated from the stitchnig shaft I4, and at other times isV driven at arelatively rapid speed, to produce a relatively'rapid feeding movement, from a second driving pulley 8 (Fig. 6) through clutch mechanism 1 controlled by a lever I9. The parts and mechanisms thus far mentioned are all usual in machines of this general type and require no further description in detail.

The clutch herein shown for clutching the drivingV pulley I5 to the stitching shaft I4 is lsimilar to those described in the above-men- 'tioned patents.4 It comprises a clutch dog 26 pivotally mounted at 2| onl a hub 22 keyed to the shaft I4 and which may be a portion of the hub of the usual hand wheel 51 (Fig. 2), said dog having a nose 23 adapted to engage a shoulder '24 formed on a disk carried by the pulley. The dog is' acted upon by a spring 25 which tends to hold it in its operative position with its .nose 23 in engagement with the Shoulder 24,

and when the parts are so engaged the clutch is operative and the shaft I4 is driven by the pul- -ley I5. The clutch is released' at proper times vby means of a clutch disengaging member 26 which, when moved into the path of movement of the tail 21 ofthe dog 20', is engaged by said tail, such engagement swinging the dog about its pivot, withdrawing the nose 23 from the shoulder24, and positively stopping the shaft I4.

The clutch disengaging member 26 is car- ,ried by an arm 28 constituting a part of a four- -armed rocker comprising a shaft 26 journalled in -the stitch frame I2 and to which said arm is secured, said shaft having fast thereon three other arms 36,3I and 32. The arm 3l engages an angular arm I9a on the lever I9, and when the .rocker is in the position shown in Figs. 1 and 5 the member is in the path of movement of the tail 21 of the dog 26, and the rapid feed mechanism is engaged and operative; but when said rocker is in the position shown in Figs. 3 and 4, the member 26 is out of the path of movement of the Ytail 21, the shaft Ulis clutched to the pulley I5, and the rapid feed mechanism is inoperative.

The arm 36 is acted upon by a spring 33 which ,tends to move the rocker into the position shown in Figs. 1 and 5 to disconnect the stitching clutch and throw in the rapid feed, said rocker being held in the position shown in Fig. 3 by a latch 34 pivoted to the stitch frame and ladapted .to engage a projection 35 on the arm 30. So long as the latch 34 engages the projection 35, i',he nstitching clutch is engaged and the rapid 2,340,391 Y' Y f feed mechanism is inoperative. The arm 32 carries a roller 36 which cooperates with a raised portion 31 of a cam bar 38 secured to the bed frame I0. When the stitch frame moves rearwardly, or toward the right as shown in the drawings, from the position shown in Fig. 1 into that shown in Fig. 3, engagement of the roller 36 with the portion 31 of the cam bar 38 causes the rocker to be moved into the position shown in Fig. 3, to cause engagement of -the stitching clutch and disengagement of the rapid feed mechanism, said rocker being retained in this vposition by engagement of the latch 34. with the projection 35. When said stitch frame moves forwardly, or toward the left in the drawings, into the position shown in Fig. 4, engagement of an abutment screw 39 carried by the latch 34 with the end of the cam bar 38 causes Said latch to be disengaged from the projection 35, thereby placing the rocker under the influence of the spring 33.

Pivoted at 50 to the arm 23 is a bell crank one arm 5I of which carries at its extremity `a roller 52 and the other arm 53 of which is connected with the arm 28 by a spring 54 which tends normally to hold said bell crank in the position shown in Figs. 3 to 5 with the arm 53 in engagement with a stop lug 55 carried by said arm 28. Secured to the stitching shaft I4 is a cam 56 which, like the hub22, may be, andv preferably is formed as a part of the hub of the hand wheel 51. The cam 56 is formed with a peripheral surface in position to be engaged by the roller 52. Said peripheral surface includes a raised, substantially concentric portion interrupted by a depressed portion or notch 58. The shape of the notch 58 is such as to provide (in the direction of rotation, as indicated by the arrows on Figs. 3 to 5) a descending portion 59 terminating in a relatively abrupt shoulder 6I). When the roller 52 engages the concentric portion of the cam 56, as shown in Fig. 4, the rocker is held in the position in which the stitching clutch is engaged and the rapid feed mechanism inoperative, but when said roller enters the notch 58, as shown in Fig. 5, said rocker is in the position with the clutch disengaging member 26 in the path of movement of the tail 21 of the dog 26 and with the rapid feed mechanism cperative. The notch 58 is angularly or circum- .ferentially advanced with yrespect to the dog 20;

the close of the stitching operation, the abutment screw 39 engages lthe end of the cam bar 38, as shown in Fig. 3, and, asthe forward movement continues, the latch 34 is disengaged from the lug 35, as shown in Fig.4, thereby putting the rocker under the iniiuence of the spring 33 which tends to turn it in a counter-clockwise direction as shown in the drawings. If, at this time, the notch 58 is not opposite the roller 52, said roller engages the concentric portion of the cam 56, as shown in Fig. 4, thereby checking movement of the rocker under the influence of the spring 33, and preventing sufficient movement of said rocker to start the rapid feed. When the stitching shaft I4 reaches an angular position to bring the notch 58 opposite the roller, said roller enters said notch, thereby permitting the spring 33 tol move the rocker into the position shown in Fig. 5

to start the rapid feed and bring the clutch dis-f" engaging member 26 into the path.v of movementv of the tail 21. At this time said tail, while apnot immediately stopped, and, as its rotation continues, engagement of the shoulder 50 at'i the end of the notch 58 with the roller 52 causes` the arm 5| to be turned into theposition shown in Fig. 1, so that, after said notch has passed.y

said roller, the clutch disengaging member rej-` mains in the path of movement of the tail 21, and, when the shaft reaches the position shown in Fig. 1, the dog 20 is disengaged from the shoulder 24 and the shaft stopped. At the beginning of the next stitching operation, when the rocker is turned into the position shown in Fig. 3, the arm 5| and roller 52 are restored to the position shown in the latter figure by the spring 54.

It will be understood' that the stitch-forming cycle is such that, as the stitching shaft reaches about the angular position shown in Fig. 4 and approaches that shown in Fig. 5, the needle is withdrawn from the Work, and that said needle remains out of the Work at least until the shaft reaches the position shown in Fig. l, in which latter position it is stopped. Consequently, although the rapid feed is started during the movement of the shaft from the position shown in Fig. 4 into that shown in Fig. 5, and before the disengagement of the stitching clutch and stopn ping of the stitching shaft, this is not objectionable since the needle is out of the work at least from this time until the shaft is stopped.

Inasmuch as the angularly advanced position of the notch 58, or low portion of the cam 56, with respect to that of the clutch dog is such as to permit movement of the rocker into the clutch-disengaging, rapid-feed position only when the tail of the clutch dog is approaching the position to engage the clutch disengaging member, and just prior to reaching the latter position, the cam 56 being otherwise so shaped as to prevent movement of said rocker into the clutch-disengaging, rapid-feed position when said tail has either just passed or is just passing the disengaging member, all possibility of the performance of another stitch-forming cycle, involving a re-entry of the needle into the work, after starting the rapid feed, as well as of a fly over, is eifectually prevented. This angular positioning of the low portion of the cam to cause movement of the rocher into clutch-disengaging position only at the time stated, Without subsequently moving said rocker out of said position prior to the arrival of the shaft at stopping position, is permitted by the pivoting of the arm 5| carrying the roller 52,

whereby said arm is normally held by the spring 54 in the operative or projected position shown in Figs. 3 to 5, but is moved into the inoperative or retracted position shown in Fig. 1 by engagement of the roller 52 with the end of the notch 58, thereby permitting the clutch-disengaging member to remain in clutch-disengaging position after having once been moved thereinto.

I claim:

1. In a sewing machine, in combination, stitching mechanism, a shaft for operating the same, means including a clutch for driving said shaft, said clutch including a dog carried by said shaft, a clutch disengaging member movable into the path of movement of said dog, a cam on said shaft having a raised portion interrupted by a notch and an arm carried by said member and provided with a roller engaging said cam, said notch being angularly advanced with respect to said dog, and said arm being normally held in an operative projected position but being movable into an inoperative retracted position by engagement of said roller by the end of said notch.

2. In a sewing machine, in combination, stitching mechanism, a shaft for operating the same,

. means including a clutch for driving said shaft,

said clutch includinga dog carried by said shaft, a clutch disengaging member movable into the path of movement of said dog, a cam on said shaft having a raised portion interrupted by a notch, a lever pivoted to said member and provided With a roller engaging said cam, and a spring for normally holding said lever With said roller in a projected position, said notch being angularly advanced with respect to said dog, and said lever being moved against the tension of said spring to cause said roller to assume a retracted position by engagement of said roller by the end of said notch.

3. In a sewing machine, in combination, stitching mechanism, a shaft for operating the same, means including a clutch for driving said shaft, said clutch including a dog carried by said shaft, a clutch disengaging member movable into the path of movement of said dog, a cam on said shaft having high and 10W portions and a shoulder joining said portions, and an element yieldably carried by said member, engaging said cam, and adapted to prevent movement of said member into the path of movement of said dog when in engagement with said high portion but to permit such movement when in engagement with said low portion, said cam being so angularly positioned with respect to said dog, disengaging member, and element that a high portion thereof is engaged by said element when said dog is opposite said member, and said element being yielded by said shoulder into a position to permit said member to remain in the path of movement of said dog until the latter engages said member.

FREDERICK A. LADD, JR.

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