US3323477A

US3323477A - Reversible feed mechanism for sewing machines

Info

Publication number: US3323477A
Application number: US376666A
Authority: US
Inventors: Arthur N Hale; Clarence C Smith
Original assignee: Union Special Machine Co
Current assignee: Union Special Machine Co
Priority date: 1964-06-22
Filing date: 1964-06-22
Publication date: 1967-06-06
Anticipated expiration: 1984-06-06
Also published as: DE6604644U; GB1056220A; DE1785528A1

Description

June 6, 1967 A. N. HALE ET AL 3,323,477

I REVERSIBLE FEED MECHANISM FOR SEWING MACHINES Filed June 22, 1964 I e Sheets-Sheet 1 mm m H a Q s E u. m

June 6, 1967 A. N. HALE ET AL 3,323,477

REVERSIBLE FEED MECHANISM FOR SEWING MACHINES Filed June 22, 1954 S'Sheets-Shet 2 June 6, 1967 Filed June 22, 1964 A. N. HALE ET AL 3,323,477

FIG3.

REVERSIBLE FEED MECHANISM FOR SEWING MACHINES Filed June 22, 1964 June 6, 1967 A. N. HALE ET AL 6 Sheets-Sheet 4 June 6, 1967 A. N. HALE ET AL REVERSIBLE FEED MECHANISM FOR SEWING MACHINES Filed June 22, 1964 6 Sheets-Sheef 5 June 6, 1967 A. N. HALE ET AL 3,323,477

I REVERSIBLE FEED MECHANISM FOR SEWING MACHINES 6 Sheets-Sheet 6 Filed June 22, 1964 YFIGJZ.

FIG.|4. FIG.|5.

F'IG.|6.

United States Patent 3,323,477 REVERSIBLE FEED MECHANISM FOR SEWING MACHINES Arthur N. Hale, Park Ridge, and Clarence C. Smith,

Chicago, Ill., assignors to Union Special Machine Company, Chicago, Ill., a corporation of Illinois Filed June 22, 1964, Ser. No. 376,666

12 Claims. (Cl. 112-210) The present invention relates particularly to mechanism for readily controlling the work feeding mechanism of a sewing machine to control the stitch length and to bring about forward and reverse feeding of the work in relation to the stitch forming mechanism of the machine under easy control of the operator of the machine. Certain aspects of the invention are also highly desirable for use in connection with other functions to be performed by a sewing machine, involving parts which must be reciprocated or oscillated to variable extents, such as the swinging of a needle bar in a zig-zag sewing machine.

Heretofore various constructions have been proposed for enabling the operator of a sewing machine to control the feed of the material being stitched, both as to direction and length of feed. However, these prior constructions, for one reason or another, have not been found satisfactory for quickly and reliably reversing the direction of feed of the work to produce stitches of the same length in either a forward or reverse direction of movement of the work in a machine capable of high speed operation.

In accordance with this invention there is provided an improved, highly reliable, and accurately adjustable mechanism for varying the stitch length, and also for bringing about a reversal in the direction of feed.

As will be explained hereinafter, the present invention is especially adapted to deal with problems involved in connection with high speed, lockstitch sewing machines. It has been found desirable in the formation of lockstitch seams to lock the two ends of the seam into the Work in a manner to prevent unravelling of the seam at either end thereof. Careful manipulation of the work at the two ends of such a seam has usually been required, by the skillful maneuvering of the work by the operator. The present invention serves to eliminate the necessity of such skill by the provision of simple, easily controlled, wholly reliable mechanism for reversing the direction of feed of the work by means operable by the hand of the operator to immediately reverse the direction of feed of the work, without the necessity, on the part of the operator, of turning the work through an angle of 180 to bring about a reverse feeding action, or the reverse movement of the work by the operator with the pressure of the presser foot released.

It is acknowledged that the reversal of direction of feed of work through the stitch forming zone is not broadly new, but the present invention is concerned with the provision of novel, simpler, more reliable and improved mechanism for achieving the desired result. Furthermore, the invention incorporates simple and reliable means for varying the stitch length that is produced.

In accordance with the present invention the change in direction of feed of conventional work feeding mechanism is achieved by a very simple and compact arrangement of various parts, wholly reliable in their operation, which may be very quickly and easily shifted from one position to another to achieve the desired result.

To attain the foregoing objectives, in connection with change of stitch length and also direction of feed, the present invention involves the provision of a rod member within the hollow portion of a drive shaft which carries an eccentric that operates the feed mechanism of the machine. The eccentric includes a component fixedly secured 3,323,477 Patented June 6, 1967 to the rotary drive shaft mentioned and another component, carrying the feed driving eccentric, which is slida- =b-ly mounted on the fixed component for movement in a direction transverse to the axis of the shaft. The slidable component of the eccentric is capable of movement to such an extent that in its normal position the point of maximum eccentricity of the eccentric is radially outward of the axis of the drive shaft in one direction, but may be shifted by the rod [member mentioned to such an extent that the point of maximum eccentricity is disposed diametrically oposite to its normal location. As a result of this the feed dog will engage the work during its movement toward the operator rather than away from the operator as it normally does. Furthermore, the invention provides means for adjustably varying the normal position of the rod member within the shaft, to thereby vary the extent of eccentricity of the eccentric. In fact in one position of the rod member the eccentric element will be retained in a truly concentric position in relation to the axis or" the drive shaft, so that no feeding action will be obtained. The construction according to the invention may be readily made to achieve this result.

In the preferred embodiment of the invention, which will be described in detail hereinafter, an adjustable dial is rotatably mounted on the frame of the machine adjacent the upper end of the vertical standard thereof and facing in the direction of the operator of the machine. This dial may be readily turned by the operator to any selected position in relation to an index or opening, thereby indicating the number of stitches per inch for which the feed mechanism is adjusted under control of the dial.

For the purpose of reversing the direction of feed under the control of the operator at any desired time, there is secured to the shaft which carries the graduated dial, a lever arm extending along the forward face of the overhanging arm of the frame. The arrangement is such, moreover, that no matter what stitch length is being produced, in accordance with the adjustment of the dial mentioned, the lever will be operated through the same distance to bring about reversal of the feed with the same stitch length for which the dial has been set. This has been made possible by the provision of special connections from the lever to the rod member within the main drive shaft which changes the eccentricity of the feed driving eccentric through an angle of 180. Thus these connections are such that whether the machine is set for the production of five stitches per inch or ten stitches per inch, or any other number, the same extent of operation of the operating lever will produce the reversal of the feed direction, with the same selected stitch length in both directions.

With the foregoing objects, purposes and features of the invention in mind, a preferred embodiment of the invention will now be described in relation to its use in a lockstitch sewing machine. This embodiment of the invention, to be hereinafter described, is illustrated in the accompanying drawings, in which:

FIG, 1 is a view, partly in front elevation and partly in vertical section, of a lockstitch sewing machine embodying the invention;

FIG. 2 is an end elevational view of the machine as seen from the left in FIG. 1, with certain parts shown in vertical section;

FIG. 3 is a detail view of a portion of the upper arm of the frame, showing the mounting of the feed reversing lever and stitch length control dial thereon;

FIG. 4 is a bottom view of the machine, with certain parts shown in horizontal section;

FIG. 5 is a transverse, vertical sectional view through the frame of the machine, taken along planes indicated by the line 55 of FIG. 1;

FIG. 6 is a plan view of an element included in the stitch length control;

FIG. 7 is an end view of the element shown in FIG. 6;

FIG. 8 is a side view of the element shown in FIG 6, as viewed from the right of the latter;

FIG. 9 is a perspective view of one element of the adjustable eccentric embodied in the invention;

FIG. 10 is an exploded perspective View of the adjustable eccentric and the strap element driven thereby;

FIG. 11 is a cross-sectional view through the adjustable eccentric and the drive shaft on which it is mounted, taken in a plane through the axis of the shaft;

FIG. 12 is a 'view, partly in elevation and partly in vertical section, showing a part of the feed bar driving mechanism and a portion of the frame in which this is mounted;

FIG. 13 is an elevational view of an arm embodied in the stitch length control mechanism;

FIG. 14 is an end view of another element in the stitch length control mechanism;

FIG. 15 is a side view of the element shown in FIG. 14 as viewed from the right of the latter;

FIG. 16 is a plan view of a sleeve member embodied in the stitch length control mechanism;

FIG. 17 is a plan view of a rock shaft which is mounted within the sleeve shown in FIG. 16 and to which the feed reversing lever is connected;

FIG. 18 is a sectional view of a pulley adapted for connection with the lower end of the arm shown in FIG. 13;

FIG. 19 is a side elevational view of a member secured to a rod mounted within the drive shaft to which the eccentric is secured;

FIG. 20 is a plan view of the feed adjusting dial and a portion of the feed reversing lever; and

FIG. 21 is a detail view of a detent shown in FIG. 20.

In the drawings the invention is shown as applied to a lockstitch sewing machine of the type disclosed in the Covert Patents No. 2,851,976, granted Sept. 16, 1958, and No. 2,977,910, granted Apr. 4, 1961. It comprises a frame structure having a base portion 10, a vertical standard 11 and an overhanging arm 12 carrying at its left end, FIG. 1, a head in which is mounted a needle bar and a presser foot carrying bar and various other parts more fully disclosed in the above-mentioned Covert patents. Extending longitudinally of the overhanging arm, and suitably journalled therein, is a main drive shaft 14. At the right end of this shaft there is secured a combined hand wheel and pulley 15 through which the shaft is rotated by suitable connections with an electric motor. Within the base portion of the frame there is a second drive shaft 16 extending longitudinally of the base portion and driven from the shaft 14 in the upper arm. For the latter purpose a toothed or corrugated :belt 17 is preferably provided, this cooperating with a toothed or corrugated pulley 18 secured to the upper shaft 14 and with a similar pulley 19 secured to the lower shaft 16. It will be understood that suitable connections of the character shown in the Covert patents mentioned above are provided from the two drive shafts for reciprocating the needle bar, driving a rotary hook, and imparting a four-motion movement to a feed dog mounted within the base portion of the machine.

Since the present invention is directed primarily to the feed mechanism of the machine, this will be described in some detail. It involves a conventional feed dog 20 (FIG. 2) which cooperates with a presser foot 21 carried in the usual manner by a spring urged presser bar in the head of the sewing machine. Feed dog 20 is secured to a member 22 which is in turn secured to another member 23, the latter being carried by a rockable and longitudinally moveable member 24. Through the various connections by which the feed dog is carried by the member 24, provision is made for suitable adjustment of its position in relation to the work. Member 24 is secured to a hollow shaft 25 rock-ably mounted in a frame 26 (FIG. 12).

This frame is in turn mounted for free rocking movement about a fixed shaft 27 carried by the base of the machine. The lower portion of the right or forward end of member 24 (FIG. 2) is connected by a link 28 with an eccentric end portion 29 (FIG. 1) of the lower drive shaft 16. Through this connection the member 24 is rocked about the axis of shaft 25 to impart lifting and lowering movements to the feed dog at appropriate times in a cycle of operation of the machine. Longitudinal movements are imparted to the feed dog, in the feed and return directions, by a pitman 31} having its rearward end 30a supported for rocking movement about the axis of a hollow shaft 26a carried by the frame 26 (see FIGS. 4, 10 and 12). The forward end of pitman 30 is provided with a strap 30]) having a needle bearing connection with a cylindrical extension 31 of the adjustable eccentric unit. Extension 31 is integrally connected with a slide block 32 forming one element of the adjustable eccentric. The slide block has inclined surfaces 32a providing a dovetail fit in relation to corresponding inclined surfaces 34a of member 34 of the adjustable eccentric. Block 32 has further extensions 33 with parallel side surfacesc 33a having a sliding fit in relation to surfaces 34b of member 34. Member 34 is secured by a set screw 35 to the lower drive shaft 16. The position of the slide block 32 in relation to member 34 is determined by sloping

surfaces

36a and 36b adjacent the inner end of a rod 36 extending longitudinally of the bore of the lower drive shaft 16, said sloping surfaces being preferably inclined at an angle of about 10 to the longitudinal axis of the rod 36. Cooperating with the sloping

surfaces

36a and 36b are the fiat ends of

pins

37 and 38, respectively, fixedly secured to the member 32. These fiat ends are inclined at the same angle as the

surfaces

36a and 36b. The pins are retained in set position by

set screws

37a and 38a, respectively, and their inner ends have a sliding fit relationship to the

surfaces

36a and 36b so as to enable the rod 36 to be shifted longitudinally within the shaft 16 to a limited extent and yet retain the member 32 of the adjustable eccentric in a quite definite position, depending upon the portions of the sloping

surfaces

36a and 36b that are positioned between the ends of the

pins

37 and 38.

Rod 36, as best shown in FIG. 11, has two portions 360 and 36d of enlarged diameter arranged for a close sliding fit within the bore of the shaft 16. That portion of the rod extending toward the right from the enlarged portion 36d is of reduced diameter and extends beyond the right hand end of the shaft 16. At its right end (FIG. 1) the reduced diameter portion of rod 36 carries a member 39, shown in detail in FIG. 19, that is held against rotation with the rod. This member is retained against axial movement in relation to the rod by means of a collar 40 and a snap washer 400, at opposite sides thereof, the collar being secured by a set screw to the rod. Member 39 is provided with a cylindrical extension having a groove 39a at each side of the central square portion of the member and having a slightly enlarged head 39b outwardly of each of the grooves 39a. These grooves are adapted to receive the forked lower ends of arms 41a of a rock member 41 mounted for swinging movement on a fixed rod or shaft 42 (see FIGS. 1 and 5). Collars 42a and 42b are fixedly secured to the rod 42 to retain the rock member 41 in proper axial relation thereto. Extending upwardly from the fixed rod 42, the rock member 41 has another pair of arms 41b. A spring 43 has a coiled portion wrapped about the fixed rod 42 with one end in engagement with a pin 44 secured to the collar 42b fixed to the rod 42 and its other end 43a extending downwardly and into engagement with a pin 41c carried by the downwardly extending arms 41a of rock member 41. This spring normally serves to rock the member 41 and its arms in a counterclockwise direction (FIG. 1) into engagement with a stop element 45, shown in detail in FIGS. 6, 7 and 8. Element 45 is secured to a cord or cable 46 for vertical movement by shifting of the latter in the manner to be explained. The

cord 46 passes downwardly through an opening 45a provided in the element 45 and the latter is held in fixed position in relation to the cord by -a set screw mounted in a threaded opening 45b of element 45.

The cord 46 is passed around a pulley 47, shown in detail in FIG. 18, mounted for free turning movement upon a frusto-conical portion of a screw 48 (FIG. 5) having screw threaded engagement with an arm 49. The latter has a hub portion 490 at its upper end secured by set screws 49b to a shaft 50 extending transversely of the vertical standard of the frame and suitably journalled in the front and rear walls thereof. For convenience in assembly of the parts the shaft 50 is formed in two sections in engagement with each other, as indicated at 50a in FIG. 5, and connected together by the hub 49a. The upper end of the cord 46 is wrapped preferably two turns around a reduced portion 51a of a pulley 51 mounted for rotation about the shaft 50. One turn of the cord extending around the pulley is passed through an opening 51b in the pulley. The free ends of the cord after being applied to the two

pulleys

47 and 51 are connected together by an element 46a secured by a set screw to overlapping portions at the free ends of the cord.

Pulley 51 is provided with slots 510, in diametrically opposed regions of a cylindrical portion thereof, adapted to receive projections 52a of a sleeve 52, shown in detail in FIG. 16, mounted for turning movement both with and in relation to the shaft 50 along which sleeve 52 extends in a close bearing fit. A dial 53 having a knurled peripheral surface is secured by a set screw 53a to the left hand end of the sleeve 52 (FIG. 5). Dial 53 and a collar 52b secured to the sleeve 52 serve to retain the latter against any appreciable axial movement in relation to shaft 50. Outwardly of the dial there is secured to the shaft 50 a split hub portion 540 of a manually operable lever 54. A screw or bolt 54b serves to secure the hub firmly to the shaft. The dial is adapted for manual turning independently of the rocking movement of the lever 54, as well as for rotation by the latter whenever the lever is rocked downwardly. For the latter purpose, as best shown in FIGS. 20 and 21, the lever 54 carries a spring detent 54c having a slightly pointed surface 54d arranged to cooperate with the grooves in the periphery of the dial 53. Thus the dial is arranged for turning movement upon the operation of the lever 54 but is capable of being turned manually in relation to the lever 54, such turning serving to cam the cooperating portion of the detent out of the grooves in the periphery of the dial.

It will be appreciated from the foregoing that whenever it is desired to change the stitch length produced by the machine it is simply necessary to turn the dial 53, by applying the hand directly to the latter, until the desired number on the dial indicating the number of stitches per inch appears through an opening 54e (FIG. 3) provided in the arm 54. Such turning of the dial will cause corresponding turning of the sleeve 52 and the pulley 51, thus shifting the cord 46 to vary the position of the element 45 in relation to the arms 41b of rock member 41. On the other hand, the downward movement of the actuating lever 54 will not only turn the sleeve 52, through the action of the detent 540, but will also turn the shaft 50 to cause swinging of the arm 49. As a result of this there will be no movement of the cord relative to the arm 49, but the swinging of the latter will cause the element 45 to swing the arms 41b in a clockwise direction (FIG. 1) and simultaneously cause the arms 41a to shift the rod 36 toward the left. This will result in the shifting of the sloping

surfaces

36a, 36b toward the left and thus cause these surfaces to cam the pin 37 upwardly (FIG. 11) or radially outwardly to bring about a corresponding shifting of the eccentric portion 31 of member 32. This arrangement is such that downward movement of the lever 54 to its maximum extent, no matter what stitch length has been selected, will shift the point of maximum eccentricity of eccentric 31 to a position 180 away from its normal position and thus bring about a reverse feeding action of the same magnitude as that for which the mechanism has been set.

The limits of movement of the lever 54 are determined by a bracket 55 secured by screws 56 to the forward face of the overhanging arm of the machine. Thus the extent to which the lever can be moved downwardly is determined by an inwardly extending portion 55a at the lower end of the bracket which cooperates with the under surface of the lever 54. The normal position of the lever under the action of spring 43 is determined by an inwardly extending shoulder (not shown) just below the lowermost of the screws 56. It will be understood that whenever the operator releases the lever 54 it will be returned to its normal, upper position by the action of the spring 43 which serves to rock the member 41 in a counterclockwise direction so that the latter, by its engagement with the element 45, Will cause shifting of the lever 49 and the lever 54 in a clockwise direction (FIG. 1).

It should be mentioned that the element 45 is provided with an opening 450 (FIG. 6) adjacent its midpoint, arranged to cooperate with the lever 49. This insures proper movement and positioning of the element 45 as it is shifted to change the stitch length. Also, as shown in FIGS. 5 and 13, the lever 49 is provided with a shoulder 490 which serves to limit the upward movement of element 45 along the lever and thus prevent undue turning of the dial 53. Downward movement of the element 45 is limited by its engagement with the pulley 47, to prevent undue turning of the dial in the opposite direction.

The mode of operation of the work feeding mechanism of the sewing machine, and the manner in which the extent of feed during each cycle of the machine as Well as the direction of feed may be controlled, are believed to be clear from the foregoing description. Briefly, there is provided a very reliable and accurately adjustable mechanism for controlling the stitch length and reversing the direciton of feed which is not subject to disturbance or misoperation during high speed operations of the machine, on the order of 6,000 or more cycles per minute. The control over the stitch length, or number of stitches per inch, is accomplished by the shifting of the position of the element 45 through the turning of the dial 53. Thus the higher the element 45 is positioned along the lever 49, by the turning of the dial with resultant shifting of the cord 46, the shorter will be the feed stroke and therefore the greater the number of stitches per inch. This is clearly shown in FIG. 1 wherein it is apparent that as the element 45 is shifted upwardly, while the lever 49 remains stationary, it will tend to rock the member 41 in a clockwise direction and thus shift the rod 36 toward the left, thereby reducing the extent of eccentricity of the eccentric. Also it is clear from FIG. 1 that the higher the posi tion of the element 45, the less will be the extent to which the member 41 is rocked by the swinging of the lever 49 in response to depressing the hand lever 54. This is due to the fact that, while the lever 49 is rocked through the same angle upon operation of the hand lever 54 to its lowermost position, the effective length of the lever 49 from the axis of shaft 50 to the active surface of element 45 will be decreased as the latter is moved upwardly. At-

the same time the effective length of the arms 41b will be increased. As a result the longitudinal movement imparted to the rod 36 will be decreased as the element 45 is shifted upwardly.

Another point of importance is that the adjustable component 32 of the eccentric unit is positively shifted in one direction or the other by the sloping

surfaces

36a and 36b on the rod 36. No spring is involved in this part of the mechanism. While a spring 43 is involved in the means for normally shifting the rod 36 toward the right (FIG. 1), the position of the rod 36 will not be disturbed by high speed operation of the machine. The small angle of slope of the

surfaces

36a and 36b and of the cooperating ends of the

pins

37 and 38 is such that there will be no tendency to shift the rod 36 as a result of high speed operation of the machine. Its position will be accurately and definitely determined by the position of the element 45 in relation to the arms 41b of rock member 41. Moreover the slight inclination of the surfaces on

pins

37 and 38, in the direction shown in FIG. 11, which cooperate with the

set screws

37a and 38a, serves to insure against any accidental displacement of the eccentric.

In the specific embodiment of the invention disclosed herein, the adjustment dial 53 is not adapted for a zero feed, but if this should be desired for any particular reason it could readily be accomplished. Provision would simply be made for enabling the element 45 to be shifted upwardly to a point substantially in horizontal alinement with the axis of shaft 50". At the same time, the arms 41b would be lengthened to cooperate with element 45 in such uppermost position. Moreover, in any construction not calling for reversal of the eccentricity of eccentric 31, the inclination of the arms 41b could be such as to cause the slide rod 36 to bring about zero eccentricity of eccentric 31 when the element 45 is at the uppermost position permitted by the construction shown. This could be the case, for example, in adapting the invention for operating some other reciprocatory or oscillatory member within the machine, such as a needle bar of a zig zag sewing machine. Positioning of the eccentric in its concentric position could thus be made to produce a straight line of stitching.

A large part of the operating mechanism of the machine is enclosed within a lubricant tight housing, and various openings or passages are provided for delivering lubricant in mist form to bearing surfaces requiring lubrication, see for example the opening 390 in FIG. 19.

While a preferred embodiment of the invention has been described in considerable detail, and certain modifications have been suggested, it will be understood that various other changes may be made in certain parts of the construction without departing from the general principles and scope of the invention as hereinafter claimed.

What is claimed is:

1. In a sewing machine having an upper and a lower drive shaft, work feeding mechanism and stitch forming devices, the combination which comprises connections from said lower drive shaft to said work feeding mechanism for operating the latter, said connections comprising an integral eccentric member mounted on said lower drive shaft for rotation in unison therewith, said integral eccentric member having a cylindrical portion serving as an adjustable eccentric and a slide portion at one end of said cylindrical portion extending outwardly in diametrically opposite directions perpendicular to the longitudinal axis of said cylindrical portion, said connections also comprising a member secured to said lower drive shaft cooperating with said slide portion of said eccentric member for driving the latter, a slidable member within said lower drive shaft, means rigidly secured to said slide portion of the eccentric member cooperating with said slidable member for controlling the eccentricity of said eccentric, and means operable at the will of the operator for shifting said slideable member within said lower drive shaft for positively changing the eccentricity of said eccentric and retaining the latter in its shifted position.

'2. In a sewing machine as set forth in claim 1, said slidable member upon being shifted by said means operable at the will of the operator being adapted to move the point of maximum eccentricity of said eccentric into a position diametrically opposite to its normal location.

3. In a sewing machine as set forth in claim 2, adjustable means for varying the extent of the normal eccentricity of said eccentric in relation to said drive shaft.

4. In a sewing machine as set forth in claim 3, said means operable at the wall of the operator for shifting said slidable member within said shaft comprising a manually operable lever adapted for movement through a predetermined arc, and connections from said lever to said slidable member for shifting the latter to different extents determined by said adjustable means as .a result of movement of said lever through the same predetermined arc.

5. In a sewing machine as set forth in claim 1, said slidable member having sloping surfaces at opposite sides of the axis of said member which are parallel to each other, and said means rigidly secured to said slide portion of said eccentric member having surfaces in engagement with said sloping surfaces of said slidable member.

6. In a sewing machine as set forth in claim, 5 said sloping surfaces being inclined at an angle of about 10 to the longitudinal axis of said slidable member.

7. In a sewing machine as set forth in claim 6, said means rigidly secured to said eccentric having slopping surfaces cooperating with said sloping surfaces on the opposite sides of the axis of said slidable member and having a close sliding fit in relation thereto.

8. In a sewing machine as set forth in claim 1, said means for shifting said slidable member Within said shaft comprising a pair of levers rockable about fixed axes in spaced relation to each other, one of said levers having an arm connected with said slidable member for shifting the latter, and the other of said levers being manually rockable and having means cooperating with said one of said levers for rocking the latter upon manual operation of said other of said levers.

9. In a sewing machine as set forth in claim 1, said last recited means comprising a stitch length controlling member readily adjustable by a hand of the operator for varying the length of the stitch produced upon each cycle of operation of the machine.

10. In a sewing machine having a drive shaft, work feeding mechanism and stitch forming devices, the combination which comprises connections from said drive shaft to said Work feeding mechanism for operating the latter, said connections comprising an eccentric mounted on said shaft for rotation in unison therewith, a slidable member Within said shaft for controlling the eccentricity of said eccentric, and means operable at the will of the operator for shifting said slidable member within said shaft for positively changing the eccentricity of said eccentric and retaining the latter in its shifted position, said mentioned means comprising a pair of levers rockable about fixed axes in spaced relation to each other, one of said levers having an arm connected with said slidable member for shifting the latter, the other of said levers being manually rockable and having means cooperating with said one of said levers for rocking the latter upon manual operation of said other of said levers, and means for varying the effective length of said levers between their pivotal axes and their points of cooperation for varying the extent of rocking movement of said one of said levers in response to a predetermined angular movement of said other of said levers.

11. In a sewing machine having a drive shaft, work feeding mechanism and stitch forming devices, the combination which comprises connections from said drive shaft to said work feeding mechanism for operating the latter, said connections comprising an eccentric mounted on said shaft for rotation in unison therewith, a slidable member within said shaft for controlling the eccentricity of said eccentric, and means operable at the will of the operator for shifting said slidable member within said shaft for positively changing the eccentricity of said eccentric and retaining the latter in its shifted position, adjustable means for varying the normal eccentricity of said eccentric in relation to said drive shaft, said means operable at the will of the operator for shifting said slidable member within said shaft comprising a manually operable lever adapted for movement through a predetermined arc, connections from said lever to said slidable member for shifting the latter to different extents determined by said adjustable means as a result of movement of said lever through the same predetermined arc, said connections from said manually operable lever to said slidable member comprising an arm connected With said lever and a rockable member connected with said slidable memher, and means shiftable along said arm -by said adjustable means, said means shiftable along said arm cooperating with said rockable member at different distances from the axis about which said rockable member is rocked.

12. In a sewing machine as set forth in claim 11, means for limiting the extent of movement of said shiftable means along said arm.

References Cited UNITED STATES PATENTS 8/1915 Ciarlo 12/1935 Bouchard 9/ 1950 Galliano 12/ 1951 Hoffmeister 11/1964 Goebel FOREIGN PATENTS 3/ 1953 Great Britain.

JORDAN FRANKLIN, Primary Examiner.

A. GUEST, Assistant Examiner.

Claims

1. IN A SEWING MACHINE HAVING AN UPPER AND A LOWER DRIVE SHAFT, WORK FEEDING MECHANISM AND STITCH FORMING DEVICES, THE COMBINATION WHICH COMPRISES CONNECTIONS FROM SAID LOWER DRIVE SHAFT TO SAID WORK FEEDING MECHANISM FOR OPERATING THE LATTER, SAID CONNECTIONS COMPRISING AN INTEGRAL ECCENTRIC MEMBER MOUNTED ON SAID LOWER DRIVE SHAFT FOR ROTATION IN UNISON THEREWITH, SAID INTEGRAL ECCENTRIC MEMBER HAVING A CYLINDRICAL PORTION SERVING AS AN ADJUSTABLE ECCENTRIC AND A SLIDE PORTION AT ONE END OF SAID CYLINDRICAL PORTION EXTENDING OUTWARDLY IN DIAMETRICALLY OPPOSITE DIRECTIONS PERPENDICULAR TO THE LONGITUDINAL AXIS OF SAID CYLINDRICAL PORTION, SAID CONNECTIONS ALSO COMPRISING A MEMBER SECURED TO SAID LOWER DRIVE SHAFT COOPERATING WITH SAID SLIDE PORTION OF SAID ECCENTRIC MEMBER FOR DRIVING THE LATTER, A SLIDABLE MEMBER WITHIN SAID LOWER DRIVE SHAFT, MEANS RIGIDLY SECURED TO SAID SLIDE PORTION OF THE ECCENTRIC MEMBER COOPERATING WITH SAID SLIDABLE MEMBER FOR CONTROLLING THE ECCENTRICITY OF SAID ECCENTRIC, AND MEANS OPERABLE AT THE WILL OF THE OPERATOR FOR SHIFTING SAID SLIDABLE MEMBER WITHIN SAID LOWER DRIVE SHAFT FOR POSITIVELY CHANGING THE ECCENTRICITY OF SAID ECCENTRIC AND RETAINING THE LATTER IN ITS SHIFT POSITION.