US2674963A

US2674963A - Spiral seam producing mechanism for sewing machines

Info

Publication number: US2674963A
Application number: US268954A
Authority: US
Inventors: Guide Anthony
Original assignee: Individual
Current assignee: Individual
Priority date: 1952-01-30
Filing date: 1952-01-30
Publication date: 1954-04-13
Anticipated expiration: 1971-04-13
Also published as: GB725417A; FR1073537A

Description

April 13, 1954 A. GUIDE 2,674,963

SPIRAL SEAM PRODUCING MECHANISM FOR SEWING MACHINES Filed Jan. 30, 1952 2 Sheets-Sheet l FIG.

INVENTOR.

WM BY ATTORNEY A. GUIDE 2,674,963

2 Sheets-Sheet 2 April 13, 1954 SPIRAL SEAM PRODUCING MECHANISM FOR SEWING MACHINES Filed Jan. 30, 1952 INVENTOR.

M KM

ATTORNEY Patented Apr. 13, 1954 SPIRAL SEAM PRODUCING MECHANISM FOR SEWING MACHINES Anthony Guide, Somerville, N. J.

Application January 30, 1952, Serial No. 268,954

' 16 Claims.

This invention relates generally to sewing machines and more particularly to devices and means for stitching fabrics with a continuous spiral seam. In its more specific aspects the invention is concerned with the stitching of generally hemispherically constructed forms of work, for example, brassiere elements. According to one method of construction, the cups or breast pocketing elements of a brassire are fashioned from either single or multiple plied material as separate hemispherical units and sewn individually to a suitable harness. This invention has for its primary objective, the formation of a spiraling continuous line of stitching on the preformed hemispherical cups Whereby not only effectively to reinforce and stiffen the cup for its supporting function but to assist in some measure, toward the production of a more truly form fitting garment.

Another aim of the invention is the construction of device peculiarly adapted for spiral sewing on hollow work pieces which is readily adjustable as to length and number of convolutions in the spiral and also to the spacing of the consecutive convolutions in the spiral. In brassiere work, for example, a fairly wide range of cup sizes need. be provided and in an equally wide range of materials, for example, in lace, silks, cottons, nylon, etc. single ply, multiple ply, plain or padded with filling materials including foam rubber. The present invention undertakes to render available a mechanism by the aid of which the conventional sewing machine may be easily adapted to the sewing of spiral seams on hemispherical work of the various types and qualities currently and conventionally used, including the few mentioned above.

The invention further aims to render available a mechanism adapted to produce the spiral stitching by means automatically responsive to to the cyclic operation of the sewing machine itself so as to eliminate the practice heretofore used of having the material that is worked upon perform the primary function of driving the feeding mechanism. In accordance with this invention, the brassire cups or similar work pieces, are stitched spirally but per se perform none of the lateral feeding means of the machine.

, Still another object of the invention is the construction of a simple and relatively inexpensive means for effecting lateral movement of the work piece relative to the stitching mechanism at a constantly varying rate proportionate to the number of stitches made by the machine, and to effect such lateral shifting without resorting to variable lead screws, drop worms,

intermittent ratcheting devices such as characteristize prior efforts to produce spiral stitching. The inventionfurther aims to produce a spiral seam having uniformly spaced convolutions, the spacing of which may be varied to suit particular conditions. Accordingly, this-invention proposes a mechanism, which in the instant embodiment has been constructed in the form of. an attachment, which is driven at any one of a several selective speeds from the wheel head of a conventional sewing machine. Through a speed reducing system, the motion derived. from the wheel head is arranged to drive the final element of the rotary train which in the instantinvention is a plate cam having a progressively enlarging periphery. Clutch means are provided for the selective engaging and disengaging of theucam with its driver so that the spiraling effect may be started and stopped atwill. The cam in turn is caused to actuate a shiftable work-guide slide, the latter being arranged to carry a center to which and about which the brassiere cup is adapted to be revolvably fixed. The parts are so constructed and arranged that the stitching is done on the inside of the cup, that is, the cup is placed on the work-guide center and held at its polar axis by a piercing point a short distance laterally offset from the needleof the machine. One side of the cup is caused to underlie the presser foot. and the portions of the cup immediately ahead and behind the presser foot curve upwardly, away from .the plane of the table. The presser foot thus engages the inside of the cup and the feeder jaw, the outside of the cup. The generally spherical contour of the cup makes, accordingly, a localized engagement with the feeder teeth but never-the-less an engagement adequate to feed the material. As the stitching progresses, the cup being transfixedby the pin at its polar axis, is free to revolve and does revolve about the axis. Simultaneously the plate cam is caused to revolve slowly, and through the means to bedescribed, effects a shifting of the polar axis of the work laterally in time relation with the stitching and in proportion to the ever changing size of the spiral to be formed. The present spiraling device is especially useful in connection with sewing machines equipped with devices for changing the length of the stitch, for when the length of the stitch is increased, the spacing of the convolutions of the spiral become closer, because the machine speed and cam speed remain constant. However, to vary the spacing of the spiral convolutions the ratio between stitching speed and cam-speed should change, and this is readily accomplished by the speed varying means provided in the cam drive train.

The present invention, therefore, comprehends a machine driven mechanism for automatically producing spiral seams on hemispherical work and with which the size of the stitch, as well as the spacing of the convolutions of the spiral, may be independently varied to suit particular requirements.

Other objects and advantages will be in part indicated in the following description and in part rendered apparent therefrom in connection with the annexed drawings.

To enable others skilled in the art so fully to apprehend the underlying features hereof that they may embody the same in the various ways contemplated by this invention, drawings dc .picting a preferred typical construction have been annexed as a part of this disclosure and, in such drawings, like characters of reference denote corresponding parts throughout all the views, of which- Figure l of the drawings is a plan view of a spiral stitching machine embodying this invention, parts of the conventional sewing machine being omitted.

Fig; 2 is a vertical sectional View substantially along lines 22 of Fig. 1.

Fig. 3 is a fragmentary view, on an enlarged scale, of portions of the cam drive and clutch mechanism.

Fig. 4 is a detail elevation of a form of clutch release mechanism.

Figs. 5, 6, and 7, are respectively plan and sectional views of portions of the cup centering and stitch feed means.

Figs. 3 and 9 are representative views of a spirally stitched brassiere cup.

Referring more particularly to Fig. 1, the invention disclosed has been illustrated in the form of an attachment capable of ready application to a conventional sewing machine whereby the latter, without serious alteration or delay may be quickly converted to a machine for spiral stitching of hollow work. The principle of this invention may of course be embodied in a custom built machine, as will be understood. In the form illustrated, however, the main elements of the invention are supported upon three relatively thin plates I9, I i, and I2 that are placed about the bedplate iii of the sewing machine [4 and suitably secured to the tabletop l5. In the instant embodiment the upper surfaces of the plates 7 lie substantially in the plane of the upper sur' face of the bedplate l3 and form in effect, a con tinuation of the working surface thereof.

The plate It, at the rear, provides a support for the main actuating train which comprises on this instance an input shaft 20 that conducts power into a speed reducing unit 2|. The unit 2i is secured to the base plate and its output shaft 22 drives another shaft 23 by means of a pair of bevel gears 24. Shaft 23 is, in this embodiment, vertically arranged in bearings provided by a bracket 25, and carries at its lower end a small spur gear 25 that meshes with a larger gear 2?. Gear 21 is journaled for free rotation upon a stub shaft 28 supported by the base plate. The teeth of the gear 21 are adapted to be engaged by one or more spring loaded clutch pawls 29 that are housed in a block 30. Block 35 is carried by a spirally contoured plate-cam 31 that underlies the gear 2'! and pivots about the shaft 28, Normally the plate-cam 31 is biased in a clockwise direction by means of a counterweight 32 connected with the cam, but may be driven in a counterclockwise direction by the retation of the gear 27, through the clutch formed by one or more of the clutch panels 29 and the teeth of the gear 2?.

The outer face 33 of the plate-cam 5! is engaged by a follower roller 34 carried at one end of a pivoted lever 35. Lever 35 pivots on a stationary pin 36 and carries at its ()161 end another follower roller 37 positioned to engage the cam face 38 of a Work-guide member 39. The work-guide member 39 is herein illustrated as a lever pivoted at 4% at the operators side of the sewing'machine head It and carries between the pivot 40 and the cam-face 38, one portion tl of a' workcentering means. The other portion of the work centering means, is a work piercing needle 42 that is carried at the free end of a U- shaped support #3. The support 53 is carried by a lever 44 which is pivoted at 5 to a block -18, the latter being also carried by the work guide member 3%.

As illustrated more clearly in Figs. 5 and 6, the work centering means ii, 42 normally occupies a position relatively close to the stitching needle of the sewing machine. However, as the platecam 35 is rotated, the work centering means is caused to shift laterally relative to the forward motion of the stitching mechanism of the sewing machine at a rate that progressively decreases as the circumferential length of the spirals stitched on the work increases so that the desired uniformity in spacing of the spiral seams may oeobtained.

At the start of the stitching cycle, the work is centered on the centering means 4!, t2, which is positioned preferably close to the stitching needle of the machine. To obtain this close relation, one of the prongs of the presser foot 48 of the conventional machine is removed, leaving but'one prong 48a remaining, on the off-side of the Work centering means, for coaction with the teeth of the work feed jaws l9 of the machine, to feed the work. As this feeding action is caused to occur at one side only of the polar axis of the work, the work is caused to revolve about the work center as the stitching progresses.

Because the work to be spirally stitched by the instant apparatus is somewhat spherically shaped, it tends to curve away in all directions from the plane of the base plate of the machine (see Fig. '7) and to facilitate inspection of the stitching operation as well'as to aid the action of the work feed mechanism of the machine in feeding the work, an auXiliar guide shield 5'! is provided. The shield 51 is mounted at the free end of a pivoted U-shaped arm 53 that is carried by a stationaryblock ll. In operation, the shield 5'! is placed inside the cup-like work and rests lightly thereon, thus holding the cup open and facilitating the rotary motion thereof through the feeder.

In the position of the parts illustrated in Fig.

1, the stitching cycle has just been started. The

plate-cam is clutched to the gear 21 and has been turned but a few degrees during which the follower 33 has traversed the leading dwell portion 33a of the plate-cam but has not been moved perceptibly thereby. During this initial movement the work guide member 39 does not respond to shift the work center laterally, and in consequence a circular seam is stitched in the workpiece. After the number of stitches required to complete a circle have been made, the spiralling contour of the plate-cam engages the follower 34 and begins to rock lever 35. Lever 35 in turn,

shifts the work guide 39 laterally. "This shifting action continues anda spiral seam is caused to be stitched in the work, in ever increasing convolutions, until the rim of the cup is reached. At this point, the sewing machine is stopped, either manually or automatically. To start a new cycle, the plate cam must be disengaged from its drive gear 21 and to accomplish the disengagement a release shoe is provided. Each of the clutch pawls 29, of which there may be four, spaced incrementally with relation to the spacing of the teeth on the driven gear, carries a roller 2911 that is adapted to be engaged by a curved release shoe 50. The shoe 50 is pivoted at and substantially follows the contour of the gear 21 for a distance somewhat greater than the normal range of angular travel of theplate cam which carries the clutch pawls 29. This shoe, may, if desired, be provided with an enlarged portion or lobe 50a operative to release the pawls automatically at a given point in the cycle. The free end 59 of the release shoe is connected with a link 53 that extends forward and hooks behind a slanted face 54 of a vertically movable release finger 55. A pull spring 56 connected with the free end of the shoe 50 and with the base plate in normally biases the curved shoe 50 rearwardly out of engagement with the pawl rollers-29a. Each of the clutch pawls is spring urged toward the gear 21 by a pull spring 29b, as shown in Fig. 3.

By the provision of the release mechanism described, the operator may, by raising the release finger 55 from his station at the front of the machine, move link 53 forwardly thus bringing the edge of the release shoe into engagement with the pawl follower rolls 29a wherever they may be located circumferentially of the gear 21, and release the clutch pawls from the gear. With the clutch pawls released, the action of the counterweight32 restores the cam to its initial position.

The follower of lever 35 follows the cam by reason of the action of a tension spring 36a that engages the lever and a stationary collar on the pivot post 35. To prevent over-movement of the release shoe 50, a stop screw 52a is provided which operates to engage the extension 52 and to fix the limit of travel thereof.

The reduction unit 2| is of standard construction and in this instance is ratioed 900:1, gears 26 and 21 are ratioed on the order of 30:144 so that the combined speed reduction is on the order of 450011. However, only about a 90 turn of the gear 21 and the plate-cam 3| is required per brassiere cup, and depending upon the rate of climb of the cam face 33 as modified by the action of lever 35 and cam face 38 of the Work guide member 39, the spacing of the convolutions of the spiral seam may be made to suit ones preference or need.

The input shaft 20 of the gear reduction unit is furnished with a cone pulley 20a, giving in this instance four speed changes between the speed of the sewing machine proper and the work feed mechanism. The cone pulley 20a is tracked by a belt 20?) that receives its power from the wheelhead of the sewing machine [4. The machine may be driven from below by another belt 20c, in the usual manner.

As indicated above, the provision of means for changing the speed of the lateral work feed mechanism relative to the forward movement of the work through the conventional feed mechanism of the machine, renders it possible .conveniently to change the spacing of the convolutions ofthe spiral seam. Since the rate of feed of the conventional work feed mechanism of the machinerbearsa direct relation to the revolutions of the wheel-head of the machine, the driving of the lateral feed train from the same wheel-head necessarily maintains the rate of lateral feed synchronized with the forward feed. Using a cam having a given rate of climb, the combined effect of the forward feed and the lateral feed is such as:to effect the stitching operation slightly diagonally, as compared with normal sewing, and this action together with the pivotal mounting of the work, causes the seam to assume the form of a spiral. The spacing of the convolutions of the spiral may be determined in the first instance by the shape of the effective face 33 of the plate cam 3|. The spacing of the convolutions of the spiral may thereafter be changed by increasing or decreasing the speed of the lateral work feed train relative to the rate of speed of the forward feed. The speed change, afforded in this instance by the stepped pulley 20a, enables this variation to be quickly achieved. In addition, a further variation may be imposed by changing the length of stitch produced by the machine. Thus, under a given set of conditions the machine may be set to produce 10 stitches per inch, and the convolutions of the spiral may be A; of an inch apart. By increasing the length of stitch, the convolutions of the spiral will come closer and if the stitch length is decreased, the spacing of the convolutions of the spiral will come wider. Accordingly, with this invention it is possible to change the relative rates of either the forward feed or of the lateral feed independently of each other and thereby achieve in-numerable variations in the spiral seam producedand rendering the invention capable of application to a wide range of cup sizes, and to produce thereon spiralreinforcing seams of such length, spacing, and stitches per inch, as may be required or suitable for the material worked upon.

Without further analysis, the foregoing will so fully reveal the gist of this invention that others can, by applying current knowledge, readily adapt it for various utilizations by retaining one or more of the features that, from the standpoint of the prior art, fairly constitute essential characteristics of either generic or specific aspects of this invention and, therefore, such adaptations should be, and are intended to be, comprehended within the meaning and range of equivalency of the following claims.

Having thus revealed this invention, I claim as new and desire to secure the following combinations and elements, or equivalents thereof, by Letters Patent of the United States:

1. The combination with a sewing machine having stitching mechanism including a needle. a presser foot and work feeder and driving means therefor, of means for guiding the work laterally relative to the direction of the forward feed produced by the stitchin mechanism at a progressively varying rate comprising a laterally shiftable work support provided with means adjacent the stitching mechanism for pivotally supporting the work thereon, means for shifting said support laterally comprising a spirally formed fiat plate cam element having a camming surface of varying contour mounted for rotary movement about a relatively fixed axis, driving connections between said cam and the driving means of the machine for rotating the cam in timed relation with the operation of the stitching mechanism of the machine, and comprising a pivotedlever means engagin and responsive to the varying contour of said cam and engaging said work support for shifting said support laterally at a rate coordinated With the rate of forward feed whereby to produce a seam in the form of a spiral.

2. The combination of claim 1 in which the means provided by the work support for pivotally supporting the work comprises a work piercing needle mounted on and movable with the work support, the axis of said needle being parallel to but offset from the axis of the needle of the sewing machine so that the needle of the sewing machine operates at one side of the work piercing needle.

3. The combination of claim 1 in which the driving connections with the drive means of the sewing machine include speed change means for varying the speed of said cam relative to the speed of the stitching mechanism whereby to effect a change in the spacin of the convolutions of the spiral seam.

4. The combination with a sewin machine having stitching mechanism includin a needle, a presser foot and work feeder and driving means therefor, of means for guiding the work laterally relative to the direction of the forward feed produced by the stitching mechanism at a progressively varying rate comprising a laterally shiftable work support provided with means adjacent the stitching mechanism for pivotally supporting the work thereon, means for shifting said support laterally comprising a plate cam element having a follower-engaging surface of varying radii mounted for rotary movement about a relatively fixed axis, driving connections between said cam and the driving means of the machine for rotating the cam at a constant rate in relation to the rate of operation of the stitching mechanism of the machine, and a two-armed lever element movable about a relatively fixed pivot and having one arm engaging and responsive to the varying surface of said cam and its other arm engaging said work support for shifting said support laterally at a rate which is a function of the rate of forward feed as modified by the varying surface of the said cam and the action of said two-armed lever, the arms of said two-armed lever being unequal in length.

5. The combination or claim 4 in which the means for pivotally supporting the work on the work support comprises a work piercing needle whose axis parallels the stitching needle but is offset therefrom.

6. The combination of a sewing machine having stitching mechanism including a needle, a presser foot and work feeder and drive means therefor, of means for guiding the work laterally simultaneously with the forward feed motion produced by the work feeder of the machine, comprising a work-supporting pivot mounted for movement in a direction laterally relative to the direction of the forward feed normally produced by the stitching mechanism, means for shifting the work pivot including a plate cam movable about a relatively fixed pivot and having a progressivelyvarying follower-engaging portion and motion transmitting means comprising a pivoted lever engaging the follower-engaging portion of said cam and engaging the said work-supporting pivot for actuating the latter, and normally operative power transmitting connections between the drive means of the stitching mechanism of the sewing machine and the said cam for rotating the cam in aforwarddirection at a constant rate relative to the rate of operation of the stitching mecha- 8 V ni'sm and whereby the said work supporting'pivot is caused to be moved laterally at a rate that varies in accordance with the varying contour of said plate cam.

7. The combination of claim 6 in which the driving connections between the cam and the drive means of the sewing machine include speed change means for varying the rate of lateral shift of the Work pivot relative to the rate of forward feed of the stitching mechanism.

8. The combination of claim 6 in which the follower-engaging portion of the plate cam is formed with a portion concentric with the axis of rotation of the cam effective to immobilize the movement of the work-supporting pivot for a predetermined number of stitching cycles so as to cause a circular seam to be produced in the correspondin portion of the workpiece.

9. The combination of claim 6 including clutch means in the power transmitting connections to the cam, means associated with the said clutch operative normally to maintain the clutch engaged and said plate cam in operation, means operative on the clutch for disengaging the clutch whereby to render ineffective said normally operative power transmitting connections to the cam, and additional means effective on the cam for actuating the cam in the reverse direction when said clutch means is disengaged.

10. The combination with a sewing machine having stitching mechanism including a needle, a presser foot and work feeder, and drive means therefor, of means for pivotally supporting a workpiece and guiding the pivotally supported workpiece laterally in timed relation with the feed motion produced by the Work feeder, comprising a Work support shiftable relative to the stitching mechanism of the machine, said work support being formed with a cam-track portion, means for pivotally supporting a workpiece on the work support in stitching relation with the stitching mechanism of the machine, a lever element positioned so as to engage the cam-track portion of the work support for shifting the support, a rotatable member positioned to engage and actuate said lever element, driving connections between said rotatable member and the said drive means of the sewing machine whereby said rotatable member is actuated and said work support is shifted in timed relation with the operation of the stitchin mechanism of the machine, and speed-change means in said driving connections for changing the rate of rotation of said rotatable member relative to and independently of the rate of operation of the stitching mechanism of the sewing machine, the said work support being constructed and arranged pivotally: to support a hemispherical workpiece and in which the needle and presser foot of the machine operate on the inside of such a piece and to one side of the polar axis thereof.

11. The combination with a sewing machine having a stitching mechanism including a needle, a presser foot and work feeder, and drive means therefor, of means for pivotally supporting a workpiece in stitching relation with the needle and for guiding the pivotally supported workpiece laterally at a rate directly related to the forward feed motion produced bythe work feeder comprising a laterally shiftable work support, a workpiercing needle carried by said work support for supporting the work in stitching relation with the needle of the machine forrelatively free rotationthereonas an incident to the forward feed motion produced by the stitching mechanism of the machine, a rotatable flat plate cam element having a varying contoured surface and power transmitting connections engaging the varying contoured surface of the cam and the work support for shifting the support laterally, including a rotatable toothed member connected with the drive means of the sewing machine for rotating the cam in predetermined ratio to the forward feed produced by the stitching mechanism of the machine, and coacting pawl means carried by the cam and normally engaging the teeth of said toothed member for imparting rotary movement to the cam, and means for disengaging the pawl means from the toothed member to discontinue the rotation of the cam while the drive means to the stitchin mechanism of the machine remains effective.

12. The combination with a sewing machine having stitching mechanism including a needle, a presser foot and work feeder, and drive means therefor, of means for pivotally supporting a workpiece and for guiding the pivotally supported workpiece lateralh relative to the forward feed produced by the stitching mechanism in timed relation with the forward feed by the work feeder, comprising a work support shiftable laterally relatively to the stitching mechanism of the machine, means comprising a work piercing needle mounted on the support for pivotally supporting a workpiece on the support in stitching relation with the stitching mechanism of the machine, a rotatable plate cam and connections between the cam and said work support for shifting said support laterally in timed relation with the operation of the stitching mechanism whereby to produce a spiralling seam on the workpiece, said plate cam having a progressively varying contour portion engaging said connections between the cam and the work support effective to cause actuation of the support laterally at a rate that progressively diminishes as the size of the convolution of the spiral seam increases, normally operative driving connections between said plate cam and the drive means of the machine for relation with the operation of the stitching mechanism of the machine, and means in said last named driving connections for changing the rate of rotation of the plate cam relative to and independently of the rate of operation of the stitching mechanism of the machine, the said work support being constructed and arran ed pivotally to support a hemispherical workpiece and in which the needle and the presser foot of the machine operate on the inside of such piece and to one side of the polar axis thereof.

13. The combination of claim 12 in which the connections between the plate cam and the work support include a pivoted lever having a portion engaging the cam and another portion engaging th work support so that the lateral shift of the work support in response to the movement of the cam is modified by the effect of said pivoted lever.

14. The combination with a sewing machine having stitching mechanism including a need e, a presser foot and work feeder and driving means therefor, of means for guiding the work laterally relative to the direction of the forward feed produced by the stitching mechanism at a progressively varying rate, comprising a laterally shiftable work support member; means carried by said work support member including a enerally U-shaped holder member; a work-piercing needle mounted upon one of said members for pivotally supporting a work piece for free rotation relative motion produced rotating the said cam in timed to said members, said holder member having a portion of one or its less adjacent the Work supporting member substantially in alignment with needle and cooperatin with said work supportin member for maintaining a work piece in place; means pivotally mountin said holder member on said work support member; means for shifting said work support member laterally comprising a cam having a spirally formed portion and being mounted for rotary motion about a relatively fixed axis; driving connections between said cam and the driving means of the machine for rotating the cam in timed relation with the operation of the stitching mechanism of the machine; and means engaging and responsive to the varying contour of said cam and engaging said work support member for shifting said work support member laterally at a rate coordinated with the rate of forward feed, whereby to produce a scam in the work piece in the form of a spiral.

15. The combination of claim i l, including a generally U-shaped guide shield having a portion adapted to be positioned adjacent the neodle of said stitching mechanism and further adapted to be positioned inside a cup-like work piece to hold the cup open and to facilitate rotary motion thereof by the feeder; and means pivotally supporting said guide shield for pivotal movement relative to said feeder.

16. The combination with a sewing machine having stitching mechanism including a needle, presser foot, a work feeder, and drive means for said machine, of means for pivotally supportins; a workpiece for free pivotal movement thereon and for guiding the pivotally supported workpiece laterally in timed relation with the feed motion produced by the work feeder, and comprising a work support shiftable laterally relative to the stitching mechanism of the machine; means comprising a work piercing needle mounted on the support for pivotally supporting a workpiece on the work support in stitching relation with the stitching mechanism of the machine; rotatable cam means; connections engaging said cam means and said work support for shifting said work support laterally, said connections including a two armed pivoted lever having one of its arms engaging said cam means and its other arm engaging said work support so that the movement of said work support in response to th movement of said cam means is modified by the action of said pivoted lever; normally operative driving connections between said cam means and the drive means of the sewing machine, whereby the cam means is rotated. in timed relation with the operation of the stitching mechanism; and means in said last mentioned driving connections for changing the rate of rotation of the cam means relative to and indepeidently of the rate of operation of the stitching mechanism of the sewing machine, said work support being constructed and arranged to pivotally support a hemispherical workpiece with the needle and presser foot of the machine operating on the inside of such workpiece and to one side of the polar axis thereof.

References Cited in the file of this patent