US1912056A - Buttonhole sewing machine - Google Patents

Description

y 30, 1933- L. L. ALMOND El AL I mmznsvsw BUTTONHOLE SEWING MACHINE Filed July 1, 1932 4 Sheets-Sheet 1 May 30; 1.. L. ALMOND El AL v v BUTTONHOLE SEWING MACHINE Filed July 1. 1932 I 4 Sheeis-Sheet 2 40 2 9. 4g fifiqi 5 y 30, 1933 n... L. ALMOND ET AL BUTTONHOLE SEWING MACHINE Filed July 1, 1932 4 Shegets-Sheet 5 llzzffrziai :5

y 3 1933- L. L. ALMOND El AL 11,912,056

BUTTONHOLE SEWING MACHINE Filed July 1, 1952 4 Sheets-Sheet 4 lczls' 0 7-11111! 5 I Mauxfi Patented M.. 30, 1933 UNITED STATES PATENT OFFICE HERRINGTON, OF TROY, AND FRANCIS CANADA, ASSIGNORS TO OLUm,

CORPORATION OF NEWYOBK BUTTONHOLE SEWING MACHINE Application nled July 1,

of the above application inclu es, among" other things, the clamping of the end of the needle thread (in startin a new seam) at a point above the work an its release just before completion of the first stitch, and the employment of clamping means below the work plate arranged to grasp andhold the thread of the first stitch as it is released by the clam above the work, the clamping means be ow the work operatingso quickly after release of the thread end by the upper clamp that it seizes both the downgoing and the upgoing runs of the first stitc but under some conditions does not pull the thread end down through the work as reliably as might be desired.

In accordance with the present invention the end of the needle thread is clamped above the work as the needle descends in forming the first stitch so as positively to prevent unthreading, but before the needle has risen substantiallyon its first upstroke, the end 01 the thread is released and is drawn down through the work and finally pulled out substantiall straight by the action of the looper or shutt e,--or by the tension of the'lower thread, and the operation of again clamping the thread at a point below the work is so delayed that only this single straight run of thread is gripped. The clamping action is thus more reliable than when it is attempted to hold two or more runs of needle thread,

thread below the work, the withdrawal of the end of the thread from above the work while by thus delaying the gripping of the 1832. Serial No. 820,444.

ed to open the upper thread-end clamp sufliciently in advance of the operation of the lower clamping means to ermit the new thread end to be drawn own completely through the work before the lower clamping means is brought into action. Other features of novelty and advantage will be hereafter more fully described by reference to the accompanying drawin wherein one desirable embodiment of t invention has up been illustrated by way of example.

In the drawings,

F g. 1 is a front elevation of a buttonhole sewin machine of a well-known t but em ying improvements provide in acii cordance with the present invention, and showing the parts in the position which they at the end of the first occupy substantially stitc cycle;

Fig. ,2 is a bottom plan view of the ma- 7e ch ne with the parts disposed as in Fi 1.;

Fig. 3 is a fragmentary plan view s o parts of the mechanism for actuating the clamp and cutter for the upper or needle thread,- -the parts being shown in the osiac tion WhlCh they take as the needle comp etes its down stroke on the first stitch cycle.

Fig. is a composite view, to large scale, illustrating in side elevation and in both end elevations, respectively, a guiding and supso pprltinggiracket for the clamp-actuating rod Fig. 5 is a fragmentary bottom plan view showing the position of the clam -control- 1mg devices 'ust as the needle begins to de- 8? scend (or a vance) in performing the first stitch cycle;

Fig. 5 is a fragmentary section, substantially on the line 5 -5' of Fig. 2, showing the position of the clamp-actuating cams at the 00 tifmfijhe glamping devices occupy the position 0 1g. I

Fig. 5" is a view similar to Fig. 5, but showing the position of the clamp-actua cams when the needle has penetrated the wor O5 far enough to make sure that it will not become unthreaded;

Fig. 5 is a fragmentary section on the line 55 of Fig. 2, showing the clamp latch levers in latched position corresponding to the loo up-stroke,

position of the parts illustrated in Fig. 5;

Fig. 6 is a view similar to Fig. 5, but showing the parts positioned just after release of the upper clamp-controlling latch lever and the release of the upper thread end;

Fig. 6 is a view similar to Fig. 5", but showing the actuating cams in the position which they occupy when the clamp-controlling devices are in the position of Fig. 6;

Fig. 6 is a view similar to Fig. 5 but showing the controlling cams in the position which they occupy when the needle is at the extreme end of its downward travel;

Fig. 6 is a view similar to Fig. 5, but showingthe latch lever for the top thread clamp released from its latch, and corre sponding to the position of the parts shown in Fig. 6;

Fig. 7 is a view similar to Fig. 5, but showing the parts in the position which they occupy when the needle has started on its first and just after the lower clamp has been actuated to seize the needle thread;

Fig. 7* is a view similar to Fig. 5, but showing the clamp-actuating cams in the position which they occupy just before release of the lower clamp-holding latch;

Fig. 7 is a view similar to Fig. 7, but showing the clamp-controlling cams in a position corresponding to that of the parts indicated in Fig. 7;

Fig. 7 is a view similar to Fig. 5, but showing both latch levers released, the position of the parts corresponding to that of the parts shown in Fig. 7

Fig. 7 is a view similar to Fi 7, but illustrating an improved form 0% actuating Spring;

Fig. 8 is a left side elevation of the latchsupporting lever, as viewed in Fig. 2;

Fig. 9 is a right side elevation of the lever shown in Fig. 8;

Fig. 10 is a front elevation of the bottom latch lever for the upper thread clamp;

Fig. 11 is a front elevation of the latch lever for the lower thread clamp;

Figs. 12 and 13 are front and rear elevations, respectively, to large scale, illustrating the improved buttonhole produced by the machine here described;

Fig. 14 is a fragmentary section substantially on the line 1 1-14 of Fig. 3, showing the top latch lever for the upper clamp in a position corresponding to that of the parts shown in Fig. 5;

Fig. 15 is a bottom plan view of the presser foot, with' certain parts removed, showing the upper thread clamp in full lines in its operative or No. 2 position and in dotted lines in its No. 1 and No. 3 positions, respectively;

Fig. 16 is a fragmentary section substantially on the line 16--16 of Fig. 15;

Fig. 17 is a section through the presser foot substantially at right angles to the plane of Fig. 16, but with the foot in upright position;

Fig. 18 is a perspective view to large scale, in vertical section, showing the position of the needle and under thread clamp as the needle descends in performin the first stitch c cle, the thread end being he d in the upper 0 amp;

Fig. 19 is a view similar to Fi ing the needle as the work and with the lower clamp;

Fig. 20 is a fragmentary section on a plane at right angles tothat of Fig. 14 showing how the thread' end is clamped beneath the bed plate; and

Fig. 21 is a section similar to that of Fig. 20 but illustrating one mode of releasing the clamped thread end.

The present improvements are shown embodied in a strai ht buttonhole machine of the well-known S inger ty e, such as is disclosed in thepatents to Hon No. 806,231, dated December 5, 1905, and No. 885,310, dated April 21, 1908, to which reference may be had for such details of construction as are not herein fully described, it being understood that the present improvements are not necessarily restricted to this particular form of machine but may be embodied in other sewing machines intended for the same or different purposes.

Referring to Fig. 12, the numeral 100 designates the front face of a piece of fabric, for example, a shirt front, having a buttonhole 101 finished at its lateral edges with rows 102 and 103 of overseam or other suitable stitches and at its ends by the transverse or barring stitches 104. and 105. Machines of the type. referred to are usually provided with means for cutting and clamping the upper thread at the completion of 18 showhaving been raised out of the thread end held in the stitching operation, and when a new buttonhole is to be started the clamped end of the thread leading to the needle eye remains above the work during the completion of the first stitch cycle and is not usually released until after the formation of a considerable number of stitches.

The present invention provides for the certain withdrawal of the end of the upper thread T down into and preferably through to the under side of the work, giving the buttonhole a finished appearance at the front face of the fabric, as shown in Fig. 12, the upper thread end T usually appearing at the rear side of the work to other with th end of the under thread as shown in Fi 13.

s shown in the present drawings the machine comprises the overhanging bracket arm 1 (Fig. 1) rising from the right-hand end of a bed plate 2 supported by the base 3. The stitch-forming instrumentalities consist of the usual eye-pointed needle 4 carried by the needle bar mounted in the usual horizontally swinging frame and deriving its vertical reciprocating movements from a main drive shaft which has bearings in the hori- 5 zontal portion of the bracket arm 1 and which is provided with the fixed drive pulley 6 and the loose pulley 7. The needle cooperates with a shuttle 'or other looper device mounted in a raceway 8 (Fig. 2) and carried by an oscillating shaft 9 which is actuated by means of the rocker 10 and link 11 from the main shaft of the machine. The work carrier or support comprises the longitudinally movable side plate 12 having an elongate opening 13 (Fig. 3), and the stationary throat plate P fitting within said opening and having the hole H (Figs. 18 and 19) for the passage of the needle. With this work support cooperates the presser foot 14 provided with 2 the elongateknife opening 15. This presser foot is supported by means of a plate 16 secured to a block 17 (Fig. 1) pivotally mounted at 18 upon a block 19 carried by the slide plate 12. The plate 16 is furnished with an arm 20 (Figs. 1 and 3) projecting to the right of the pivot 18, as viewed in Fig. 1, and by means of this arm the plate 16 and the presser foot may be rocked about the pivot 18 to lift the presser foot from the throat plate.

For depressing the arm 20 there is provided a bell crank lever 21 (Figs. 1 and 3) free to turn on a shaft 22 mounted in bearings 23 projecting forwardly from the bracket 1. This bell crank lever comprises the forwardly directed arm 24 (Figs. 1 and 3) from which depends a pivoted link 24 whose lower end is guided in an opening in a bracket 25 projecting forwardly from the bed plate 2. This link 24 carries a bracket provided with a stub shaft on which is mounted a roller carried by a bracket 26 (Fig. 1), said roller resting upon the upper surface of the arm 20.

The forward end of the lever arm 24 is furnished with an opening for the reception of a chain 27 which extends down to a treadle (not shown) actuable by the foot of the op erator to swing the bell crank lever, thereby causing the roller 26 to bear upon the arm 20, and thus rocking the plate 16 and raising the presser foot from the work.

The machine is provided with automatic stop mechanism of a usual type adapted to stop the machine automatically at the end of a certain predetermined number of stitch cycles. This stop mechanism comprises a swinging frame 28 (Fig. 1) arranged to rock in a vertical plane between pintle members 29 (Fig. 2) and normally tending to swing in a clockwise direction under the action of a spring 30 (Fig. 1). The frame 28 has slide bearings for a stop pin 31 adapted to move vertically in the frame and which is urged upwardly by means of a spring 31. This stop pin 31 is adapted, when the frameis swung into vertical position, to cooperate with a stop cam 32 fixed to the main drive shaft, the cam being arranged depress the pin 31 against the action of the spring 31 and then to. permit thein-to snap up into a socket in the cam, t ereby positively preventing further movement of the drive shaft, the swinging ofthe frame ,to stop position causing the belt shifter B to move the belt from the fast pulley 6 onto' the adjacent loose pulley 7. The stop pin 31 has a fixed collar which, in the downward movement of the pin, is carried down below a sprlng-pressed pin (not shown) in a boss 22 carried by an arm 22 secured to shaft 22. Thus when pin 31 snaps up into the cam socket, the arm 22 is raised, thus rocking shaft 22.

To prevent raising the presser foot during the operation of the machine, there is provided a link 33 (Fig. 1) connecting the frame 28 with a rocker member 34 disposed beneath the arm 20, and when the frame 28 is positioned as in Fig. 1, that is to say, while the machine is operating, the rocker 34 is so disposed that the arm 20 can not be depressed, but when the frame 28 is moved to stopping position, the rocker 34 is swung downwardly so as to permit depression of the arm 20.

The slide plate 12 is supported by a transversely movable slide 12 (Fig. 1), and'these plates are moved in properly timed relation by means of the usual cam 35 (Fig. 2) which is actuated through proper connections to the main drive shaft.

Referring more particularly to Figs. 3, 15 16 and 17, the presser foot 14 is furnished with a horizontal slot 36 for the reception of the upper thread clamp and cutter. This slot is conveniently provided by making the presser foot in two parts, one of which, 14*, is removable and which is so shaped as to provide the slot 36 between its upper surface and the opposed lower surface of the presser foot proper. The cutter 37 and the clamp 38 are secured to a vertical shaft turning in a boss 39 forming a part of the presser foot and provided at its u per end with a lever arm 40. The cutter 3 cooperates with the edge of the presser foot 14 at the end of slot 15 to cut the upper thread, while the clamp 38 cooperates with a surface 38" (Fig. 16) above the slot to clamp the thread when the clamp and cutter are in their operative or No. 2 position, shown in full lines in Fig. 15. The surface 38 is cut away at 38 (Fig. 16), and when the clamp is moved to its secondary inoperative (or No. 3 position, Fig. 15) the thread is released from the clamp.

The lever arm 40 is pivotally connected to a downwardly bent portion 41 (Figs. 1 and 3) of a controlling rod or bar 42. This bar is supported and guided by a bracket 43 (Figs. 3 and 4) having spaced upstanding ears 43 and 43" at its opposite ends, respecso as first to" tively, said ears having openings through which the bar 42 slides. referably the o ning in the ear 43 is elongate to accomm ate slight lateral movement of the left-hand end of the bar. The bracket 43 is carried by a plate 44 (Fig. 3) secured to the left-hand end of arm 20. The rod or bar 42 is provided with a fixed collar 45 (Fig. 3) d1s osed at the left of the bracket ear 43", an with a second fixed collar 48 disposed to the left of the bracket ear 43". A coiled compression spring 47 encircles the rod 42, such spring be ing isposed between the ear 43 and the collar 48. The compressive force. of this spring thus tends to move the collar 48 with the rod 42 to the right, as viewed in Fig. 3,

thus tending to move the clamp and cutter to its No. 3 or thread-releasing position, as indicated in dotted lines in Fig. 15.

To the right of the bracket 43 the rod 42 is provided with a fixed truncated conical abutment 50 which cooperates at times with parts, now to be described, to limit movement of'the bar 42 to the right.

Referring particularly to Figs. 1, 3 and 14, a detent lever 51 is mounted upon the lefthand end of the shaft 22, above described, and extends rearwardly. This detent lever is provided at its free end with a latch member 52 which overlies the shaft 42. This latch is pivotally supported on the end of the lever 51 to swing in a vertical plane and is furnished with a tail 53 which is: normally held against stop member 54 bimeans of a spring 54. As thus'arranged t e free end of the latch may be raised without changing the position of the lever 51, but the latch can not be depressed below the position shown in Fig. 14 without corresponding movement of the lever 51.

A second detent lever 56, for determining the movement of the bar 42, is also shown most clearly in Figs. 1 and 14, this lever being pivotally supported at 57 upon a block .58 carried by the arm 20, the rear end of the lever being urged upwardly by a spring 56 (Fig. 1). This lever 56 projects rearwardly from its pivot to a point slightly beyond the shaft or bar 42 and is adapted at times to stand directly across the path of movement of the bar so as to limit such movement of the bar to the right. To cushion the blow of engagement of the bar 42 with the lever 56, it is preferred to provide the lever 56 with a spring member 56" (Figs. 1 and 14) at its left-hand face as viewed in Fig. 3.

The lever 56 is provided with a downwardly directed arm 56 whose lower end is disposed substantially opposite to a window 59 (Fig. 1) formed in the base 3. At its lower end the arm 56 is furnished with a horizontal portion 60 upon which is mounted an elongate latch 61 adapted to swing in a horizontal plane and which is provided with a spring urging it to stand substantially in the position indicated in Fig. 5 where its longest dimension is substantially perpendicular to the front face of the machine. This latch cooperates at times with a disk 63 having a smooth fiat front face and a beveled edge 64. This disk is carried by a slide bar 65 guided in an opening in a bracket 66 secured to the bed plate 2 and also passin through an opening in the front flange 67 (Fig. 5) of the bed plate. A coil spring 68 Figs. 5 and 14) surrounds this slide bar 65, hearing at one end against the bracket 66 and at its other against a pin 69 (Fig. 14) secured in the bar, the spring thus tending to move the bar 65 and the disk 63 rearwardly. The rear end of the slide bar 65 (Figs. 5, 6 and 7) lies in the horizontal plane of movement of one arm of a lever 70 pivoted at 71 and having a second arm 70', (Fig. 10) which is en aged by the right-hand portion of a spring 0 tending to swing the lever in the counterclockwise direction, as viewed in Fig. 5. The lever arm 7 O is provided with a projecting toe 72 at its right-hand end (Fig. 6) adapted to be engaged at times by a substantially spherical stud 73 projecting from the lower end of an arm 74 (Figs. 1 and 6) forming a part of the bell crank lever 21 above described, the arm 74 passing down through a suitable opening in the bed plate. Movement of the lever 21 for raising the presser foot swings the arm 74 rearwardly and thus by engagement of the stud 73 with the finger 72 swings the lever 70 to the set position shown in Fig. 5, thus at the same time permitting the sprin 68 to retract the disk 63 to the position of ig. 5. In order to hold the lever 70 in this set position after the presser foot has been released by the opera tor, there is provided a latch member 75 (Figs. 5, 8 and 9) carried by a supporting lever 76 (Fig. 8) pivoted at 77 on a block 78 (Fig. 2) secured to the under side of the bed plate and urged upwardly by a spring 76. The latch 75 is adapted to engage the edge of the lever arm 70 to hold the latter in set position. A second latch lever 7 0 is also pivoted at 71, the lever 7 0 being disposed directly below the lever arm 7 0 and preferably having a notch or recess 79 provided with a beveled or inclined inner wall. The lever 76 carries a block 81 pivoted at 82 and urged by a spring 83 into contact with a stop 84, the block being free to swing to the left, as viewed in Fig. 9, against the tension of spring 83, but being limited by the stop 84 against movement to the right. This block is disposed in the plane of rotation of a clamp actuating cam 85 on the shuttle oscillating shaft 9. This cam has a projecting toe 86 and when the cam is oscillated in one direction, the toe 86 freely tips the block 81 and passes above it without actuating the lever 76; but when the toe 86, in turning in the opposite direction, engages the top surface of the block 81, as shown in Fig. 7", the lever 76 is moved down a ainst the action of its retaining spring 76", t us depressing the latch 75 (Flg. 7"; and permitting the edge of the lever arm 0 to escape,the beveled inner wall of notch 79 ensuring release of lever 70 whenever latch 75 is depressed far enough to engage said surface.

The retaimng lever 76 is provided with a second block 81 (Fig. 8) ad ustably secured to the lever and disposed in the plane of rotaa When cam 86 engages block 81, it displaces latch 75 only enough to release lever arm 7 0 whereupon, in response to spring the toe 72 of lever 70 moves quickly in a counterclockwise direction, thus projecting the disk 63 forward to the position of Fig. 6.

The left-hand end of the lever 70 is rovided with an elongate slot 87 adapte to receive a pin 88 hereinafter referred to, and when the latch 75 is displaced by action of cam the lever 70 moves over to the osi tion shown in Fig. 7 under the action 0 the left-hand portion of spring 70.

The left-hand end of the lever arm 70 is provided with a finger 87 disposed at one side of pin 88 which projects from a slide bar 89 (Fig. 2) which is guided in suitable ways carried by the bed plate. This slide bar 89 carries a thread-clamping member 90 (Figs. 18 and 19) arranged to reciprocate across the needle holeH in the throat plate P, and if desired may be arranged to push a bight of the lower thread U into engagement with a resilient cutting plate 91 having a sharp edge. To facilitate this action, there is provided a loop-forming arm 92 pivoted at 93 (Fig. 2) to a fixed part of the machine and having a slot which receives a pin 94 projecting from the slide bar 89. Thus as the slide bar is moved, the end of the arm 92 is swung rapidly so as to provide a bight of the lower thread for engagement by the end of the clamping member, and to draw enough thread to start the next buttonhole.

That portion 95 of the work support which lies just to the left of the needle opening H, as viewed in Fig. 18, cooperates with the lower thread clamp 90, as hereinafter described, in clamping the end of the upper thread T. For this purpose the clamp 90 is rovided with an elongate opening 97 (Fig. 19) through which the needle passes when the clamp is in the position indicated in Fig. 18. To permit release of the end of the upper \per thread T is cut and the thread T after the first few stitches of the seam have been safely formed, the under surface of the part 95 of the plate 12 may, if desired, be provided with a transverse notch or groove 98 (Fig. 21), and as'the plate 12 moves to the left after the seam has been started, the groove or notch 98 is brought into registry with the thread end held by the clamp, so that the end is free to be drawn out of the clamp.

The operation of the machine is substantially as follows, it being assumed that the machine has nearly completed a buttonhole and is just on the point of stop ing. a At this time the thread clamp control ing -parts above the bed plate are positioned substantlally as in Fig. 14, while the parts below the bed plate occupy a position substantially as shownin Fig. 2. Referring to Fig. 14, 1t will be noted that the latch '52 of the lever 51 is hearing against the right-hand surface of the cone 50 and is holding the rod 42 to the left against the action of the spring 47. As thus positioned the clamp and cutter for the upper thread is in its retracted, primary inoperative, or No. 1 position, as indicated in dotted lines in Fig. 15.

When the machine actually reaches the end of the buttonhole-forming operation, the

frame 28 is allowed to swing m a clockwise directlon,

free to be lifted. At the same tlme the pin 31 s brought into the path of the cam 32, which first depresses this pin, carrying its fixed abutment collar to a point beneath the snap pin in the boss 22" on the arm 22; and when the stop pin 31 snaps up into the socket 1n the cam 32, the a pin in the boss 22*, thus swinging the arm 22 and turning the shaft 22 so as positively to lift the lever 51, thereby latch 52 from behind the cone 50. This allows the rod 42 to snap suddenly to the right, as viewed in Fig. 1, until its end is arrested by the lever 56,--the blow being cushioned by the spring 56". This movement of'the rod 42 to the right moves the clamp and cut ter into the operative or N o. 2 position shown in full lines in Figs. 15 and 16, where the upend leadin to the needle is clamped against the surface 38 of the presser foot. In order to remove the work from beneath the presser foot, the

latter must now be raised, and the operator depresses the treadle, thereb rockm the thus moving the rocker 34 from beneath the arm 20, leaving the presser foot butment collar lifts the.

removing the a counterclockwise movement,

ly as viewed in Fig. 2) and at the same time swinging lever 7 0 to the position of Fig. 5. This movement of the sli e also swings the arm 92 so as to form a bight in the lower thread and at the same time advances the clamp 90 across the needle hole in the throat plate, thereby cutting the lower thread by engagement with the sharp edge of the plate 91 When the levers 70 and 70 are swung as 'ust described, they clear the end of the latch 5, allowin the atch-actuating spring 76 to lift the atch to the position of Fi 5 where its vertical edge stands in the p ane of movement of the levers 70 and 70 so as to lock them in this set position. During this setting of the lever 70, the spring 68 retracts the disk 63, thus permitting the spring-actuated latch 61 to assume a position shown in Fig. 5'wherein its length is substantially perpendicular to the face of the disk.

To start the machine, the stop frame 28 is swung over to the left by means of the usual connections to a foot treadle and the belt is shifted onto ulley 6. As the needle advances in per orming the first stitch cycle, it descends throu h the openin in the throat plate, as indicate in Fig. 18, t e free end of the needle thread T still being clam ed between the clamping member 38 and t e surface 38 of the presser foot (Fig. 16), it being remembered that at this time the end of the rod 42 is still in engagement with the lever 56.

After the needle completes its downward the shuttle carries a bight of the upper thread T around the lower thread U while the needle is risingto a point above the throat late. Duringlt e descending movement of the needle, t e shaft 9 is rocked in direction, as viewed in Fig. 5 until it reaches the position of Fig. 6", but as the needle starts to move up, the shaft 9 begins its reverse movement. Before the needle has reached the limit of its downward stroke, but after it has descended far enough to make sure that it will not become unthreaded, if the thread-end isreleased from the upper clamp, the cam 86 arrives substantially at the position of Fig. 6, where it enages block 82 and depresses the lever 76 ust far enough to allow the lever arm 70 to escape from latch 75, whereupon the ri hthand portion of the spring 7 0 (as viewe in Figs. 5 and 6) immediately snaps the lever 70 back to the position shown in Figs. 1, 6 and 7, where its toe 87 comes into contact with the fixed abutment block 87 (Fig. 7), thus limitin its further movement. is movement 0 the lever forces the slide bar forwardly, pushing the disk 63 forwardly and, by means of the latch 61, pushing forwardly the lower end of the lever 56". This de resses the rear end of the lever 56 to a point below the rod 42, thus permitting the latter, under the action of its spring 47 to move to its extreme right-hand position (Fig. 3). In this position the upper clamp and cutter are moved to their secondary inoperative or No. 3 position (shown in dotted lines in Fig. 15) wherein the clamp 38 is positioned opposite to the recess 38 in the presser foot, thus permitting the upper thread freely to escape from between the clamp and the presser foot.

The needle now begins its upward movement, and, as it rises, the action of the shuttle, or the pull exerted by the lower thread draws the free end of the needle threa downwardly to the lower side of the work. However, before the needle has risen far enough to pull the end of the needle thread T out from the bight of the under thread U the cam 85, which during the descent o the needle was carried past the block 81 (rocking the latter out of its path) returns to the position of Fig. 7 where its toe 86 enages the block 81 which is now prevented rom rocking by its stop pin 84. Further movement of cam 85 in the clockwise direc tion now forces the block 81 downwardly (Fig. 7") and thus moves latch lever 76 down far enough to release the lever 7 0 from the end of the latch 75, as shown in Figs. 6 and 7, the inclined wall of the notch 79 in lever facilitating such disenga ement. The release of lever 7 0 from latch 5 permits the left-hand portion (Fig. 7) of spring 70 to snap thelever70overtotheposition shown in Figs. 2 and 7, thereby by means of the pin 88 moving the slide bar 89 back to the posit tion of Fig. 1 and thus carrying the lower thread clamp 90 back to its original position Since the upper thread has previously been carried down through the opening 97 in the clamp 90, the upper thread is nipped between the clamp 90 and the under side of the art 95. The machine may now continue to orm stitches, first forming the row of stitches 102, then the barring stitches 104, then the second row of overseam stitches 103, and finally the barring stitches 105, whereupon t-he machine stops with the upper thread clamped as above described.

During the above sequence of operations, the slide plate 12 first moves to the left, during the formation of the first row of stitches, and during this movement the bracket 43 moves to the left with its ear 43 bearing against the stop collar 48, and thus carries the rod 42 with its cone 50 so far to the left as to permit the latch 52 to ride up over the cone and to drop behind the latter. At about the same time the latch toe 61 reaches the bevel at the left-hand edge of disk 63 and slips off just as latch 52 drops behind the cone. When the latch toe 61 slips off of the disk, it allows the lever 56 to rise so that its rear end engages the rod 42, ready to jump up fore the left-hand ear 43 holding the needle thread at the work in starting a seam, means for reopposite to the end of the rod when the rod has moved far enough to the left.

In making the second row of stitches the bracket 43 moves to the'right, and during this movement the engagement of the latch 52 with the cone 50 prevents the rod 42 from moving to the right with the bracket. Theremoves away from the collar 45 and compresses the spring 47. When the stop motion operates, the latch 52 is lifted, allowing the rod 42 to spring to the right until it engages the lever 56. At this time, the latch toe 61 is substantially parallel to the face of the disk 63. The slide. plate 12 continues to move to the right until the completion of the buttonhole, whereupon the machine stops with the parts substantially in the osition as described.

T e machine thus automaticallycompletes the buttonhole, cutting both upper and lower threads, and completing the buttonhole with both ends of. each of the upper and lower threads extending down irito or through the work. It is contemplated that other and equivalent means may be found for performing the novel process herein claimed and that changes in size, proportion and relative arrangement of parts in the mechanism disclosed may be made without departing from the spirit of the invention.

Fig. 7 illustrates an actuator spring similar in purpose and function to the sprmg 7 0 but so arranged that the pressures exerted upon the respective levers and 7 0 may be relativel varied. To this end the spring is mounte -upon the rocker 100 pivotally sup ported on a shoulder screw 101 projecting downwardly from the bed of the machine. The rocker has a curved slot 102 concentric with the axis of the screw 101, and a set screw 103 passes through the slot for holding the rocker in adjusted position. The head end of the screw 101 projects downwardly below the rocker and forms a post about which a length of spring wire is coiled, the

opposite end portions 104 and 105 of said length of wire engaging the lever 7 0 and 70 respectively. The coiled portion of the wire turns freely upon the screw 101 but has a projecting loop portion 106 which bears against a stud 107 projecting downwardly from the right-hand end of the rocker, as viewed in Fig. 7'.

With this arrangement, adjustment of the rocker 100 about the axis of the screw 101 changes the pressure exerted by the respective arms 104 and 105 upon the levers 7 0 and 70, thereby permitting variation of the timing of the operation of the upper and lower clamps respectively.

e claim:

1. A sewing machine having means for a point above leasing the thread end during the descent of the needle in erforming the first stitch cycle, means for pu ling said end through the work, and means operative, during the next ascent of the needle, temporarily to clamp and hold the thread end at a oint belowthe work.

2. A sewing mac ine having means for holding the needle thread end above the work, means for holding the needle thread end at a point below the work, and means operative, during the performance of the first stitch cycle in starting a seam, to release the thread end from the holding means above the work and, after an appreciable interval of time, to actuate the means below the work to cause it to grip the thread end.

'3. pparatus for making a sewed seam -compr1sing an eye-pointed needle, means for advancing and retracting the needle through the work, means for holding the end of the needle thread at a point above the work as the needle advances through the work in performing the first stitch c cle, means operative to release such end befbre the needle completes its first advance movement thereby to permit the end to be drawn through the work, and means operative subsequently to such release, but before the needle completes its next upward movement, to clamp the thread end at a point below the work.

4. A sewing machine having a work support a needle, and means for reci rocating the latter, a clamp above the worl? support for holding the thread end as the needle descends in performing the first stitch cycle, thread-clamping means beneath, the work support, and means operative at spaced intervals of time, during the first stitch cycle, to actuate the upper clamp to release the thread end and to actuate the lower clamping means to seize the thread end.

5. A sewing machine having a work support a needle, and means forv reciprocating the latter, a clamp above the work support for holding the thread end as the needle descends in performing the first stitch cycle, means for openin said clamp to release the thread end, a latc preventing operation of said clamp-opening means at the beginning of the first stitch cycle, thread-clamping means below the work support, means for closing said clamping means whereby to seize a thread, latch means preventin such clamp-closing means from acting at t e beginning of the stitch cycle, and a pair of cams operative during the first stitch cycle to release said latch means one after the other.

6. A sewing machine having a work support, a needle, and means for reciprocating the latter, a clamp above the work support for holding the thread end as the needle descends in performing the first stitch cycle, spring means tending to open said clamp to release the thread end, thread-clamping means below the work support, spring means tending to close said clamping means whereby to seize and hold a thread, latch means preventing both said spring means from acting as the machine starts the first stitch cycle, an cam means operative to actuate the latch means during the first stitch cycle so as to permit the respective spring means to operate successively, first to release the thread end, and thereafter to clamp it below the work support.

7. A sewing machine having a work support, a needle, and means for reciprocating the latter, a clamp above the work support for holding the thread end as the needle descends in performing the first stitch cycle, thread-clamping means below the work support, means tending, at the start of the sewing operation, to cause the upper clamp to release the thread and to cause the lower clamp to seize the thread, latch devices preventing actuation of the upper and lower clamping devices at the start of the sewing operation, and means operative successively during the first stitch cycle to retract the latch for the upper clamp and subsequently to retract the latch for the lower clamping means.

8. A sewing machine having a work sup port, a needle, and means for reciprocating the latter, a clamp above the work support for holdingthe thread end as the need e descends in performing the first stitch cycle, a presser foot, means for lifting the presser foot, thread-clamping means below the work support, spring means for actuat ng said clamping means, means for energiz ng such spring means, latch devices for retaining the upper clamp in thread-clamping position in opposition to such spring means and for retaining the lower clampi i means in inoperative position in op os1t1on to the spring means, and a pair 0 cams arranged to act successively durin the first stitch cycle to retract the respective latch devices whereby first to open the upper clamp to release the thread and thereafter to close the lower clamp to seize the thread.

9 A sewing machine having a work sup port, a needle,and means for reciprocating the latter, a clamp above the work support for holding the thread end as the needle descends in performing the first stitch cycle, thread-clamping means below the work support, and means operative during the first stitch cycle to actuate said clamping means one after the other, respectively.

10. A sewing machine having a work support, a needle, and means for reciprocating the latter, a clamp above the work support for holding the thread end as the needle descends in performing the first stitch cycle, thread-clamping means below the work support, and a pair of cams operative successively during the first stitch cycle to actuate said clamping means one after the other.

11. A sewing machine having a worksupport, a. needle, and means for reciprocating the latter, a' clamp above the work support for holding the thread end as the needle descends in performing the first stitch cycle, thread-clamping means below the work, a cam operative as the needle nears the end of its advancing stroke during the first stitch cycle to cause the upper clamp to release the thread, and a cam operative as the needle begins its return stroke during the first stitch cycle to cause the lower clamp to seize the thread.

12. A sewing machine having a work support, a needle, and means for reciprocating the latter, a clamp above the work support for holding the thread end as the needle descends in performing the first stitch cycle, clamping means below the work support, means operative to release the thread from the upper clamp during the down stroke of the needle on the first stitch cycle, means for pulling the thread end down to the lower side of the work, and means for actuating the lower clamp as the needle begins its upstroke on the first stitch cycle to seize and clamp the thread end.

13. A sewing machine having a work support, a needle, and means for reciprocating the latter, a clamp above the work support for holding the thread end as the needle descends in performing the first stitch cycle, a spring for actuating the upper clamp, said spring tending at the beginning of the sewing operation to cause the clamp to release the thread, a movable stop preventing such action of the clamp at the beginning of the sewing operation, thread-clamping means below the work support, a spring tending at the beginning of the sewing operation to actuate said clamp to seize a thread, a movable stop preventing such action of the lower clamping means at the beginning of the sewing operation, and a pair of rotary cams operative during the first stitch cycle to retract said stops successively whereby to permit said clamps to operate one after the other to release the thread and to seize it, respectively.

14. A sewing machine comprising stitchforming mechanism including a needle, means operative during the first stitch cycle for holding the needle thread end until the needle has advanced far enough to prevent unthreading and then to release such thread end, and means operative subsequently during the first stitch cycle to seize a single run of the needle thread end at a point below the work.

15. A sewing machine comprising stitchforming mechanism including a needle and loop-forming means, clamping means for holding the end of the needle thread at a point above the work during the first stitch cycle until the needle has nearly completed its first down stroke, clamp opening means operative to release the thread end, anfl clamping means subsequently operative, during the completion of the first stitch cycle, 'to seize a single run of the needle thread at a point below the work to prevent its withdrawal from the work.

Signed by LESTER L. ALMOND and 30mm G'I'ON at Troy, N. 35., this 2d. clay of June 1932, and by FRANCIS A. Mammzws at Kitchener, Ont, this 7th day of June 1932 LESTER L. ALMOND. HOLLAND HERRINGTON. F. A. MATTHEWS.

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