US1416003A - Work-shifting mechanism sob sewing- machines - Google Patents

Description

A. H. DE VOI-.

.WORK SHIFTING MECHANISM FOR SEWING MACHINES APPLICATIQN FILED FEB. 2l, 19|?. l

Patented May 16, 1929.

2 SHEETSSIIEET I.

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INVENTOR MMM TI'ORNEY A. H. DE VOE. WORK SHIFTING MECHANISM FOR SEWING MACHINES.

APPLICATION FILED FEB. 2l. |917.

Patented May 16, 1922.

2 SHEETS-SIIEET 2.

ATTORNEY Cil UNITED srAflgs Partnr ortica.

ALBERT n.

DE VQE, 0F WEST'FIELD, NEW JERSEY, ASSIGNOR TO THE SING-ER MANU- FACTURING COMPANY, A CORPRATON OE NEW JERSEY.

Laiaoos.

Specification of Letters Patent.

`Pa.tent-edMay 16, 1922.

Application filed February 21, 1917. Serial No. 150,003.

T0 all fwiomc' may concern.'

Be it known that 1ALennr H. Dn Voir, a citizenof the United States, residing at lVestfield, in the county ofUnion and State of New Jersey, have invented certain `new and useful improvements in TWork-Shifting Mechanisms for Sewing Machines, of which the folio 'ing is a specification, reference being had therein to the accompanying drawings.

This invention relates to an improvement in sewing machines for producing spaced groups or successions ofstitches, and is directed particularly to means for producing relative shifting movements between the stitch-forming mechanism and the worlr intermediate stitching periods7 with means of control whereby each group or succession of stitches relative to the preceding group may be positioned either uniformly within a series or arbitrarily at` the will of the operator preparatory to the production ofany individual group or succession of stitches.

lVhile the present improvement is not limited to embodiment in machines of any one of various types,`it has been designed particularly for use in connection with the buttonhole cutting and stitching machine forming the subject of my pending applications Serial No. 69,6414-, filed December 31, 1915. and Serial No. 135,15@ filed December 5, 1916.

Heretofore, provision has been made in buttonhole machines forthe automatic shift of the work between stitching positions to space the buttonholes, with the object of saving time by automatic control of 'the stich-forming and work-handling devices throughout a plurality of buttonhole-produr-ing cycles; but the means to this end heretofore devised have been found impractical in commercial operation because of a lack of the necessary flexibility to adapt the machines for the varying conditions com.- monly encountered in the manufacture of garments.

V The work-shifting means of my said application Serial No. 69,644 has for one of its important objects a capacity for variation,

by predetermined adjustment, in the angular relation of successively produced b uttonholes, while effecting a uniform' spacing of the same apart; while the corresponding mechanism of my said application Serial No.

.135,154 sought to further increase the ilexibility of themechanism to accommodate different working conditions by providing not only for the rendering of the same ineffective when required,but by making it controllable arbitrarily to vary the normal length of shift between stitching positions at any stage .of a continuous series of buttonhole-producing cycles.

The present invention has for its object to still further increase the capability of this class of mechanism to accommodate itself to normal working conditions by not only increasing the range of adjustment in the angular relation of successive buttonholes of a series but by subjecting such adjustment to arbitrary manual control, so that the operator may determine precisely the position of any buttonhole both regarding its angular relation to and its spacing from the preceding buttonhole.

ln its preferred embodiment, the improvement comprises suitable stitch-forming and work-feeding mechanisms in, conjunction with a traveling work-gripping device, which latter may consist of the opposed cutting elements of a buttonhole cutting device with means for applying to said elements iirst a yielding work-gripping closing movement upon the work preparatory to a workshitting movement, followed by a second stage or cutting movement for producing the buttonhole slit atits arrival in stitching position. `The cutting device preferably cornprises a travelling frame or carrier sustaining both ofthe cooperating cutting elements and having a transverse sliding connection at one point with a fulcrum-stud around `which it has turning movements and relative to which it has bodily shifting movements. This carrier has independent connections at separated points by means of suitable pitmen 'with crank-arms upon an actuating rock-shaft of which that controlling the bodily .transverse movement of. said `carrier relative to the fulcrum-stud is adjustable upon its respective crank-arm toward and from the rock-shaft for both uniform and arbitrary or manual control so as to vary or 'substantially prevent movement of the carrier transversely to its fulcrum-stud in conjunction with the turning movements imparted'by the other of said link connections.

Further objects and constructive features of the present improvement will be understood by reference 'to the following detailed description in connection with the accompanying drawings, in which- Fig. 1 is a side elevation of a buttonhole cutting and stitching machine embodying the present invention. Fig. 2 is an enlarged gti-ont elevation and Fig. 8 a plan of the work-shitting and cutting mechanism detached from the other parts of the machine. Fig. 4 is an elevation representing the means for imparting operative movements to the actuating rock-shaft, and Fig. 5 is a rear side elevation representing the means for producing the work-gripping and cutting movements of the slit-cutting device.

As shown in the drawings, the machine is constructed with a frame comprising vthe base 1` from which rise the standards 2 sustaining in coaxial relation the main-shaft 8 and the constantly running driving pulley 4 imparting. through suitable clutch devices and Vother connections. operative movements to the several trains of mechanism.

Slidingly mounted upon the base 1 is the travelling stitch-'frame 5 sustaining a bracket member 6 in which is ournaled the reciprocating needle-bar 7 carrying the needle 8 cooperating in practice with looptaking elements sustained by the frame 5. These stitch-forming elements are suitably mounted in their respective supports to perform partial rotations in buttonhole stitching cycles by means of an operative connection with the feed-cam 9 which derives its operative movements from connections with the main-shaft 8.

The longitudinal feeding or stitch-spacingA movements and the lateral side-shift movements are imparted to the stitch-trame by connections with the feed-cam including roller-studs 10 and 11, respectively, entering suitable cam-grooves in the lower face of the feed-cam cylinder 9.

The non-travelling work-holder, in which the work is held during the successive stitching cycles, is not shown herein as it forms no material part of the present invention, but it may be constructed for cooperation with the buttonhole cutting mechanism as represented in my said pending applications.

As represented in the drawings, the travelling work-gripping and cuttingy device comprises a vertically and horizontally movable cutter-lever 12 having intermediate its ends a-vertical tubular boss 13 in which is fitted the guide-studv 14 depending from the laterally extending thrust-.plate 15 which has the forked lug` 16 embracing the steady pin 17 carried by the cutter-lever 12. The collar 18 fixed upon the enlarged lower end of the guide-stud 14 rests uponr a fixed part of the `machine base 1, and between the shoulder afforded by the enlarged portion of said stud and the upper end of a socket surrounding the same within the boss 18 is interposed a spring 19 by means of which the cutter-lever is normally maintained yielding-ly in upper or inoperative position.

Secured upon the Jfree end ot the thrustplate 15 is the cutter-block or plate 2O disposed beneath and in operative relation with the relatively movable upper cutting knife 21 sustained by the overhanging member 22 of the cutter-lever or frame. rlhe upper and lower cutting elements 21 and 20 are maintained normally separated by the previously described action of the spring 19.

The cutter-lever is formed at its Yforward end with a transverse apertured boss 28 in which is secured by set-screws 24 the slidepin 25 mountd in alined transverse bearing apertures in the spaced members 26 of a yoke 27 having its hub 28 journaled upon the fixed headed fulcrum-stud-29 which is ecured by the set-screw 30 within a vertical aperture of the bracket-member 81 sustained by the base 1. The cutting device, comprising the frame or carrier 12 with the cutting elements 20 and 21, is thus supported at its forward end upon the pivotally mounted yoke 27 and at a point intermediate its ends by means of the guide-stud 14 resting upon the base 1.

As set forth in my said applications, the cutter-lever has at its inner end adjacent the overhanging member 22 a boss 32 in which is secured a stud 83 carrying a roller 34 adapted for engagement with the lower operative face of thc rail 35 sustained at the lower end of the slide-frame 86. The slide-frame 36 is formed with apertured upper and lower lugs 37 and 318 fitted uponthe vertical push-rod 39 which is journaled in suitable bearing members 40 vand 41 of the frame extension 2.

The rod 39 has fixed thereon in its lower portion the collar 42 carrying the laterally extending roller-stud 48 and normally pressed upwardly by means of a spring 44 interposed between the same and the lower bearing 41, the elevated position ot' the rod 39 being determiuedby engagement or' the collar l5 fixed upon its lower end with the bearing member4l. interposed between the upper lug 87 oIn the slide-frame 86 and a thrust nut 46 applied to the threaded upper portion of the push-rod 39 is a spring 47 acting to press the slide-frame Vdownwardly with its lug 38 seated upon the collar 42 (Fig. 5). lower portion of the frame 36 and the collar 42 respectively are the forked arms 48 and 49 embracing the steady pin 50 rising` from a depending portion 2 of the frame extension 2', by means of which the parts are prevented 'from turning.

The roller-stud 48 normally lies within the path of movementof the cam-block 51 secured upon the periphery of the cam-cylinder 9 and provided with a backwardly and VExtending laterally from the4 ries with it the roller-stud 34 and cutter-` lever 12 and thus causes the upper cutting element 21 to approach the lower cutting element 20 and yieldingly grip the work between them. The force of this gripping actionis determined by the strength of the spring 47 under the normal tension placed thereon by the thrust-nut 46.

The front side face of the rail 35 is formed in the end portion farthest from the cutterlever with'a vertical channel laterally closed by a cap-plate 35 to afford a guideway for the vertically reciprocating plunger-bar 52 pivotally connected at its upper end with the lower extremity of thev pitman 53 whose 0pposite end is pivotally attached to the shorter arm of a rock-lever 54 mounted, upon the fixed fulcrum-pin 55 and having its other arm provided with the lateral roller-stud 56 (Fig. 1). The roller-stud 56 is normally maintained byV means of a suitable spring (not shown) resting upon the upper face of the cutter-actuating cam-disk 57 formed with the actuating projection 58 by means of which the rock-lever 54 is tilted for reciprocation of the plunger-bar 52. The cam-disk 57 is fixed upon the vertical shaft 59 having speed-reducing worm-and-worm wheel connection with the main-shaft 3, as represented in dotted lines in Fig. 1, and carries a. driving pinion 60 meshing with a gear-wheel 61 secured tothe cam-wheel 9 and from which the latter derives its operative movements.

lNith its connections with the main-shaft represented in the drawings, the cutter-actuating shaft 59 performs several rotations in each `button-hole-producing cycle, and the plunger-bar 52 performs a like number of reciprocations, all but one of which are idle or ineffective. As the cutting device, with the work gripped between itscutting elements, reaches stitching position in a work-shifting movement, the roller-stud 34 assumes a posiytion beneath the end of the then retracted plunger-bar which in its next descent thrusts such roller-stud positively downward and thereby depresses the cutter-lever 12 and forces the upper cutting element through the work to cut the buttonhole slit. At this point in the cycle of the machine, the untilthen open worl -clamp is closed upon the work, the cutting elements separated and the cutting device withdrawn laterally into retracted position and the stitching of the buttonhole is performed as usual.

Journaled in bearings 62 upon the base -1 isa rock-shaft `63 provideduponits rear-` ward end (Figs. 1 and 4) with a crank-arm 64 carrying a roller-stud 65 extending beneath the straight lower operative edge 66 y roch-shaft 63.`

of a lever 67 fulcrumed at 68 upon the post 69 rising from the base 1. The lever 67 has at its Lipper edge intermediate its ends the extension 70 to the face of which is secured by means of screws 71 the angular tappet member 72, the opposite end portions of whose upper edge are downwardly inclined for successive engagement with the rollerstuds 73 projecting from the periphery of the cam-cylinder 9. The engagement of the tappet-member 72 by the studs 73 causes first the gradual depression of the lever 67, then the maintenance :of the same in depressed position and the final gradual release of thesame to permitit to vreturn to initial. elevated position, the rock-shaft 63 performing corresponding rocking movements by reason of the described connections.

The rock-shaft 63 has secured thereon the split hub 74 of an upwardly extending arm 7 5 which is provided with the forwardly eX- tending sleeve 7 6, Upon this sleeve and adjacent the hub 74 is loosely mounted the hub 77 of a lever 7 8 having therein' a series of apertures 79 disposed in slightly angular and'intersecting relation with a corresponding series of holes 6() inthe level' 7 5. These overlying'levers are adapted to be coupled together in different angular relations by means of the pin r81 entering registering holes at the crossing of the two series, as represented in dotted'lines in lligj2.- The lever carries a ball-stud 82 embraced by a strap at one endv of a pitman 83 whose opposite end is provided with a similar strap einbracing a ball-stud 34 carried by the cutter-lever 12 adjacent the roller-stud 34 (Fig. 4

`Surrounding the rock-shaft` 63 is the spring 85 having one end fixed to the rearward bearing 62 and the opposite endrsecured to a'collar 86 fixed upon said rockshaft and acting upon the latter to yieldingly maintain a stop-screw 87 carried by the hub 77 of the lever 7 8 in contact with a stopplate 88 vwhich is sustained by an arm of the plural-armed treadle-actuated lever 89 fulcrumed at 90 and having a. lateral arm adapted for engagement with thestop-spring 9' (Figl 1) Secured upon the forward end of the sleeve 76 is a split collar 92 at one end of a forwardly extending bar'93 formed at the other end with a hub 94 carrying a steady pin 95 entering an aperture of the machine frame. Extending upwardly from the hub` 94 is a segmental crank-arm 96 formed with a curved slot 97 which is entered by a studpin 98 movable within said slot toward and from the: steady pin 95 upon the axis of the The stud-pin 98 is formed at one end with a ball 99 embraced byy a strap at the end of a pitman-lever 100 formed intermediate itsV ends with a second strap embracing a ball-stud 101 sustained by the boss 23 of the cutter-lever 12.

The pitman-lever has adjacent the stud-pin 98 an extension 102 apertured to receive one end of a spring 103 whose opposite end is connected to a stud 104 sustained by the bed 1. rIhe pitman-lever 100 has an oppositely directed extension apertured to receive a treadle connection represented in the form of a chain 106. The crank-arm96 has adjustably secured thereon by means of the clamp-screw 107 passing through the slot 97 a divided stop-block 108 adapted to arrest the pitman-lever 100 in a predetermined initial position of adjustment under the action of the spring 103, while permitting such pitman-lever to be moved by the operator in opposition to said springv under the action of the treadle connection 106.

In the rocking of the shaft 63 under the action of the cam-Wheel studs 73 upon the tappeti-member 72, the crank- arms 75 and 96 are moved in the direction of the stitchforming mechanism, thereby acting through the pitmen 83 and 100 to move two spaced portions of the cutter-lever 12 defined by the ball- studs 84 and 101 in the same direction but in extent corresponding with the distances of the ball connections 82 and99 from the, axisof the shaft 63.

Obviously the crank-arm 75 imparts to the cutter-lever a turning movement about the fulcrum-st-ud 29 while the crank-arm 96 is adapted to impart to the opposite end of the cutter-lever a bodily movement upon the slide-pin 25 transversely of such fulcrumstud. These independent movements derived from the actuating rock-shaft are thus adapted to produce a resultant curvilinear movement of the intermediately disposed cutting elements (Fig. 3) of which the curvature is determined by the relativeamplitudes'of the component movements.

The length of the crank-arm 96 isi so proportioned relatively to the pitman connection of the crank-arm 7 5 that when the stud 98 is in its highest position, as represented in Fig. 2, the effective lengths of said crankarms are the same, and in the actuation of the rock-shaft 63 its described connections with the cutter-lever 12 act as a parallelmotion device of which the cutter-lever is a member, whereby the latter is caused to move rectilinearly, every point in such lever performing a. rectilinear movement of the same extent as every other point. 'The release of the treadle connection and adjustment of the stop-block 108 to any position intermediate the outer end of the crank-arm' 96 and its axis of movement permits the connection between the pitman-lever 100 and said crankarm to assume such a position that the pivotally mounted end of the cutter-lever will perform a bodily movement transverse to the fulcrum-pin of less extent than the opposite end of the cutter-lever, thereby imparting to the cutting elements a movement in a substantially circular path of a degree of curvature determined by said adjustment.

It is of course obvious that, the adjustment of the pitman-lever connection, with its respective crank-arm may be adjusted within the limits for which the machine is designed so as to determine the exact angular reletion between the initial orvfretracted position and final or stitching position of the cutting elements, and that it is not essential that their path of movement intermediate these positions should be precisely circular.

In the machine represented in the drawings, provision is made for temporary displacement of the upper and lower stitchforming elements, as also the needle-throat v 109 and a section. 110 of the work-plate, to

enable the cutting elements to move into stitching'position in shifting the work, between buttonhole positions and cutting the same to form each buttonhole-slit preparatory to a stitching operation.

In the use of the machine as thus described, the coupling pin 81 is adjusted within the requisite registering apertures 79 and 80 to determine the normal retracted position of the crank-arm 75, and the stop-block 108 is set to produce the requisite effective length of the crank-arm 96 for movement of the cutting elements 20 and 21 in a path of the desired curvature. The machine being set in motion and the cutting elements having been lightly pressed upon the work to gripl the same, the cam-wheel studs 73 act upon the lever 67 to effect the rocking of the shaft 63 by means of which the opposite ends of the cutter-carrier are movedbaclnvardly to carry the cutting elements into stitching position in a curved path at the end of which the cutting knife 21 invariably assumes a position in parallelism with the direction of feed and in fixed relation with the stitchforming elements. The cutting elements having performed their second or cutting stage of movement to produce the buttonhole slit iny cutting position, the worle is clamped in the work-holder and the cutting elements separated and returned to initial retracted position, the stitching succeeding the cutting operation in the usual manner.

In operation upon the buttonhole flap of a shoe upper, the buttonholes should not maintain their parallelism throughout the series, but their angular relation well as their spacing apart requires modification, dependingvupon theclass of worl; operated' upon. In the machineof the present improvenient, the angular relation of the knife 21 in its initiall retracted and final positions may be varied by the manual tilting of the pitman-lever 100 so as tovary its point of connection with the crank-arm 96, and this change may be effected in any degree between the normal position determined by the i, so

i is retracted from cutting position.

stop-block 108 and extreme straight-line position, as represented in Fig. 2, depending entirely upon the `will of the operator. As described in my said application Serial No. 135,154, the spacing apart of the buttonholes .may be changed arbitrarily without disturbing the normal adjustment of the machine by the manual operation of the stop-plate carrying lever 89 so as to change the initial retracted position of the crank-arms 7 5 and 96. Thus, the present machine provides means for changing, both normally and arbitrarily on the part of the operator, both the initial position andthe angular relation of the cutting elements in respect to their position at the button hole cutting point. It will be observed that the capacity of the present mechanism for variation of its effect upon the work is due to the provision for adjustment which is constantly under the control of the operator throughout substantially the entire cycle of operation of the machine, or at all times at which the cutting device Under such condition, `changes in the path or direction of travel of the cutting device may be made arbitrarily by the operator for any individual buttonhole of a` connected series of which the component buttonholes are adapted to be automatically produced and spaced in sequence in each cycle of operation of the machine. The manual control l of the relative `location of the buttonholes i ing largely upon the type of machine to which it may be applied; and it is therefore evident that the invention is not limited to the construction and arrangement of parts herein shown and described.

I-Iaving thus set forth the nature of the invention, what I claim herein is 1. In a sewing machine, in combination, stitch-forming and feeding mechanisms for producing within a stitching cycle stitching upon the work in a defined pattern, and means acting upon the work and adapted to shift beyond the normal range of action of the stitch-forming mechanism that portion of the work last within such range in the stitching of said pattern, and comprising a work-gripping device, and shifting means for movlng it in a predetermined path and provided with adjusting means whereby said gripping device may be caused to travel eitherin a rectilinear or a curvilinear path.

2. In a sewing machine, in combination,

stitch-forming and feeding mechanisms for producing within a-stitching cycle stitchingT upon the work in a defined pattern, and work-shifting means acting upon the work intermediate stitching cycles and comprising a work-gripping device, and shifting means adapted to move the same in a curved path and provided with adjusting means whereby the degree of curvature of said path may be varied at will between a predetermined maximum degree and a straight line.

3. In a sewing machine, in combination, stitch-forming mechanism, feeding mechanism for effecting the spacing of the stitches in the work, and work-shifting means acting independently of the feeding mecha-l, nism and comprising a work-gripping device, a fulcrum, and connected means for shifting said gripping device respectively about and bodily transversely of said fulcrum.

l. In a sewing machine, in combination, stitch-forming mechanism, feeding mechanism for effecting the spacing of the stitches in the work, and work-shifting means acting independently of the feeding mechanism and comprising a work-gripping device, a fixed support, a fulcrum sustained thereby, and means for imparting to said gripping device compound shifting movements relatively to said fixed support about and transversely of said fulcrum.

5. In a sewing machine, in combination, stitch-forming mechanism, feeding mechanism for effecting the spacing of the stitches in the work, and work-shifting means acting independently of the feeding mechanism and comprising a work-gripping device comprising opposed gripping elements and a carrier therefor, means connected to said carrier at spaced points forshifting the same, and means for varying the effective actionof the respective carrier-shifting means.

6. In a sewing machine, in combination, stitch-forming mechanism, feeding mechanism for effecting the spacing of the stitches in the work, and work-shifting means acting independently of the feeding mechanism and comprising a work-gripping device, a fixed fulcrum, and means for turning said gripping device upon and for shifting it bodily transversely of said fulcrum.

7. In a sewing machine, in combination, stitch-forming mechanism, feeding mechanism for effecting the spacing of the stitches in the work, and work-shifting means aeting independently of the feeding mecha-` nism and comprising a work-gripping device, a fixed fulcrum, a transverse guideelement mounted upon said fulcrum with which said gripping device has a sliding` connection, and means for turning said gripping device upon and for shifting it bodily transversely of said fulcrum.

8. In a sewing machine, in combination, y stitch-forming mechanism, feeding mechanism for effecting the spacing` of the stitches in the work, and work-shifting means acting independently of the feeding mechanism and comprising a work-gripping device, a fixed fulcrum, means for turning said gripping device upon and for shifting it bodily transversely ot said fulcrum, and adjusting means for relatively changing the extent of said turning and bodily shifting movements.

9. In a sewing machine, in combination, stitch-forming mechanism, feeding mechanism for effecting the spacing of-the stitches in the work, and work-shifting means acting independently of the feeding mechanism and comprising a work-gripping device, a fixed fulcrum, means for turning said gripping device upon and for shifting it bodily transversely of said fulcrum, and adjusting means connected with said bodily shifting means and adapted to vary the extent of said "bodily shifting movements.

10. In a sewing machine, in combination, stitch-forming mechanism, feeding mechanism for effecting the spacing of the stitches in the work, and work-shifting means acting' independently of the feeding mechanism and comprising a work-gripping device, a fixed fulcrum, means for turning said gripping device upon and for shifting itbodily transversely of said fulcrum, and adjusting means constantly under the control of the operator connected with said bodily shifting means and adapted to vary the extent of said bodily shifting movements.

1l. In a sewing machine, in combination, a work-gripping device, a fixed fulcrum, means for turning said gripping device upon and for shifting it bodily transversely of said fulcrum, adjusting means for determining normally the relative extent of said turning and bodily shifting movements, and additional shifting means constantly under the control of the opera-tor for temporarily varying such normal adjustment.

12. In a sewing machine, in combination, stitch-forming and feeding mechanisms, and worl -shifting means acting independently of said feeding mechanism and comprising a work-gripping device, a fulcrum therefor, a reciprocating actuatingmember, and independent connections between said workgripping device and said actuating member for shifting said gripping vdevice respectively about and transversely of said fultransversely yof said fulcrum.

'crank-arm toward and from the rock-shaft.

15. In a sewing machine, in combination, a work-gripping device comprising opposed gripping elements Aand a carrier therefor,

lmeans for opening and closing said gripping device upon the worln'a parallel motion device comprising saidvcarrier as a member, and adjusting means for a member of' said parallel motion device for varying the extent of relative 'travelof different portions of said carrier.

16. In a sewing'machina in combination, a work-gripping device, shifting means :for imparting thereto movements of a predetermined range, means for adju-sting vboth the extent and direction of said fmovements. and means constantly under the control of lthe operator for further varying the direction of movement of said gripping device.

17. In a sewing machine, infcombination, a work-gripping'devica 'shifting means for imparting thereto movements of a predetermined range, means for adjusting both the extent and direction of said movements, and means constantly under the control of the operator for further varying both the extent and thedirectionof movement of said gripping'device.

18. Ina sewing machine, in combination, feeding mechanism, a worlcgripping device, shifting means operable in alternation with the feeding mechanism for imparting to the work-gripping ldevice 'movements `of a vpredetermined range, means for adjusting both the extent and direction of said movements,

and means constantly under the control of the operator Vfor further varying either the extent or direction of movement of said gripping device.

19. In a sewing machine, in combination, stitchforming` mechanism, a workgripping device, and shifting means operable intermediate `operative periodswo'f the stitchingforming mechanism for producing between them relative travelling 'movements inapredetermined path, said shifting means being provided with adjusting means whereby said path of relative travel maybe lrectilinear or curvilinear in form.

'20. In a sewing machine, in combination,

stitch-forming mechanism, a work-gripping device, shifting means ;for producing between them relative travelling movements 'in a vpredetermined path, adjusting means forzthe shifting means whereby said path of relative .travel may be `rectilineario1- nirvilinear in form, `and means constantly under the control of the operator for further varying said path of relative travel.

21. In a buttonhole sewing machine, in combination, stitch-forming mechanism, a travelling work-cutting device comprising opposed work-engaging elements, means for imparting to said cutting elements in successive stages nippingfollowed by cuttingmovements, and shifting means connected with said cutting device and adapted to move the same while its cutting elements are in nipping relation in a curved path toward the stitch-forming mechanism, said shitting device being provided with adjusting means whereby the degree of curvature of said path may be determined between a predetermined maximum of curvature and a straight line.

22.*ln a buttonhole sewing machine, in combination, stitch-forming mechanism, a travelling work-cutting device comprising opposed work-engaging elements, means for imparting to said cutting elements in successive stages nippingfollowed by cuttingmovements, shifting means connected with said cutting device for movement thereof in a curved path toward the stitch-forming mechanism while its cutting elements are in nipping relation, adjusting means for said shifting means whereby'the degree of curvature of said path may be determined between a predetermined maximum of curvature and a straight line, and means constantly under the control of the operator for further varying the degree of curvature of said path.

23. In a sewing machine, in combination, stitch-forming mechanism, feeding mechanism for imparting thereto travelling movements in a defined path during the sewing periods, and shifting means; acting upon the work between sewing periods and adjustable to move it in paths respectively ot' different character in relation to the path of travel of the stitch-forming mechanism.

24. A buttonhole sewing machine, having, in combination, a rotary stitch forming mechanism and a work-clamp relatively movable to sew about a buttonhole, and means for moving the work in a variable curved path to space the buttonholes.

25. A buttonhole sewing machine having, in combination, buttonhole sewing mechanism, work spacing means, and adjusting means for varying the direction of the work spacing movements while the machine is in operation.

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

ALBERT H. DE von.

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