US2808793A

US2808793A - Feeding mechanism for sewing machine

Info

Publication number: US2808793A
Application number: US552751A
Authority: US
Inventors: Waldemar A Ayres
Original assignee: White Sewing Machine Corp
Current assignee: White Sewing Machine Corp
Priority date: 1955-12-13
Filing date: 1955-12-13
Publication date: 1957-10-08
Anticipated expiration: 1974-10-08

Description

0d. 8, 1957 w, A, AYRES 2,808,793

FEEDING MECHANISM FOR SEWING MACHINE Filed Dec. 13, 1955 4 Sheets-:Sheet 1 INVENTORN- Wane/v41? 14. Aye

Arr-521v ys MM i W. A. AYRES FEEDING MECHANISM FOR SEWING MACHINE 4 Sheets-Sheet 2 k INVENTOR. Mme-Mm? A/Iynss v BY 4 n n I QWQMM ArraewE/fi Oct. 8, 1957 Filed Dec. 15, 1955 Oct. 8, 1957 w, Es 2,808,793

FEEDING MECHANISM FOR SEWING MACHINE 4 Sheets-Sheet 5 Filed Dec. 15, 1955 R Win 1 1 1/ m INVENTOR. Mmmw A/lykss A rramvE Y8 Oct. 8, 1957 w, AYREs 2,808,793

FEEDING MECHANISM FOR SEWING MACHINE Filed Dec. 13, 1955 4 Sheets-Sheet 4 INVENTOR. I Mews/ML? AAy/vsa United States Patent FEEDING lVHLCHANISM FOR SEWING MACHINE Waldemar A. Ayres, Lakewood, Ohio, assignor to White Sewing Machine Corporation, Lakewood, Ohio, a corporation of Delaware Application December 13, 1955, Serial No. 552,751.

19 Claims. (Cl. 112-210) This invention relates to a sewing machine and more particularly to a feed mechanism for a sewing machine.

An object of the invention is to provide an improved and novel feed mechanism for a sewing machine and wherein the stitch length and direction can be readily selected and varied while the feed height of the feed dog can be regulated to provide drop feed or various height feeds as desired.

Another object is to provide a feed mechanism as referred to above and which mechanism is compact, par: ticularly in a direction transversely of the bed of the sewing machine, so that the feed mechanism can readily be contained in the narrow bed of the free arm type of sewing machine. V

A still further object of the invention is to provide a feed mechanism wherein the feed dog is readily detachable and removable from the remainder of the mechanism when desired so as to provide easy access to the rotary hook or other parts of the feed or sewing mechanisms contained beneath the bed of the sewing machine.

Still another object of the invention is to provide a feed mechanism for a sewing machine whereby the stitch length can readily be varied from zero to maximum in either direction.

A still further object is to provide a feed mechanism for a sewing machine which is simple in construction, accurate, compact and eflicient in operation.

Further and additional objects and advantages not hereinbefore specified will become apparent hereinafter during a detailed description of embodiments of the invention which is to follow and which embodiments are illustrated in the accompanying drawings forming part of this specification and wherein Fig. 1 is a fragmentary plan view of the bed of a sewing machine with a portion of the bed plate broken away to show a feed mechanism embodying the invention and located below the bed plate.

Fig. 1a is a detail fragmentary vertical sectional view taken substantially on line 1a1a of Fig. 1- looking in the direction of the arrows.

Fig. 2 is a vertical sectional view taken substantially on line 22 of Fig. 1 looking in the direction of'the arrows.

Fig. 3 is a detached fragmentary perspective detail of a portion of the mechanism for raising and lowering the feed dog and for adjusting the height of the movement thereof from a drop feed position to a maximum high feed position.

Fig. 4 is a fragmentary vertical sectional view through a portion of the bed and a portion of the head of a sewing machine having the feed mechanism shown in Figs. 1 and 2 and illustrating the parts for adjusting the feed height and the stitch length and direction, said view being taken substantially along line 4-4 of Fig. 5 looking in the direction of the arrows.

Fig. 5 is a horizontal sectional view taken substantially on line 55 of Fig.- 4 looking in the direction of the arrows.

Fig. 6 is a fragmentary front elevational view of the bed and head of the sewing} machine and illustrating on the front of the head the knob for controlling the stitch direction and length and the knob for controlling the height of the feed. V

Figs. 7 and 8 are views similar to Figs; 1 and 2 but illustrating a modified form of feed mechanism embodying the invention.

Fig. 9 is a detached fragmentary plan view of the element of the mechanism for varying the stitch length and direction and shows a different form of such element than the one disclosed in Figs. 1 and 2 and in Figs. 7- and 8, and

Figs. 10 and 11 are views similar to Figs; 1 and 2 and Figs. 7 and 8 but illustrating a still further form of'feed mechanism embodying the invention.

The feed mechanism embodying the invention has been illustrated herein as applied to a sewing machine of the type having a horizontal hook rotating on a vertical axis but it will be understood that the mechanism is susceptible of use in other types of sewing machines.

Referring to Figs. 1, 2, 4, 5 and 6 the bed of the sewing machine constitutes a housing for the sewing and feed mechanisms of the machine and for portions of the control elements for such mechanisms as well as for the drive to such mechanisms as will be wellunderstood in the art;

The bed comprises a horizontal bed plate 15 enclosing the upper side of the bed and provided with an opening over the sewing mechanism which is closed by the detachable and removable needle plate 16. The bed also includes as part of the housing a downwardly extending supporting structure indicated at 17 and including vertically spaced

horizontal wall portions

18 and 19. The vertical standard of the head of the sewing machine is indicated at 20 in Figs. 4 to 6 inclusive and is secured to the upper side of the bed plate 15. I

The rotary hook or sewing mechanism is indicated at 21 and is secured to a vertically extending shaft 22 rotatable in suitable hearings in the

horizontal wall portions

18 and 19 and having fixed to it intermediate said

portions

18 and 19 the toothed drive pulley 23. Spaced from the" shaft 22 but parallel thereto is a second vertically extending shaft 24 rotatable in suitable hearings in the

horizontal wall portions

18 and 19 of the bed and extending upwardly above the portion 18. The shaft 24 has fixed to it intermediate the wall portions 18 and 19 a toothed drive pulley 25 of predetermined larger diameter than the diameter of the drive pulley 23 so that the

shafts

22 and 24 will rotate in properly timed relationship to each other and to the other operative parts of the sewing machine as will be well understood in the art.

An endless toothed driving and timing belt 26 operatively passes around the

pulleys

23 and 25 and said belt extends around a toothed drive pulley (not shown) 10- cated in the bed beneath the bed plate and carried on the lower end of a vertical drive shaft (not shown) which isoperatively' connected to the horizontal shaft in the hori zontal arm of the head that extends to and operates the reciprocating needle bar as will be well understood in the art and hence need not be shown herein. i

The horizontal wall portion 18 has's'ecured to.- its upper

side supporting blocks

27 and 28 with the block 27 lo cated adjacent the front of. the machine and the block 28 spaced therefrom transversely of the machine and toward the rear thereof. The upper ends ofthe

blocks

27 and 28 form a supporting abutment for the bedplate 15 and the needle plate 16. a V i The

blocks

27 and 28 support a fixed guide'rod 29 iextending therebetween intermediate the horizontal wall portion 18 and the bed plate 15. .A slide member 30is pro:- vided with spaced parallel cars 31 having aligned openings Patented Oct. 8', 1957 p a therein and through which the rod 29 extends," wherefore the slide member 30 can have horizontal reciprocating movement on the rod 29 transversely of the bed.

The rear end of the slide member 30, i. e., the upper end as viewed in Fig. 1, is provided with a downwardly offset and laterally extending arm 32, the free end of e which engages in a horizontal groove 32a formed in a guide block 33 secured to theWa-ll portion18 of the bed, wherefore the slide member 30 while free to reciprocate on the rod 29 is held against rocking movement thereon. The front end of the slide member 30, i. e., the lower end as viewed in Fig. 1, is provided with a lug 34, the upper side of which has a groove 34a therein parallel to the rod 29.

The feed dog is indicated at 35 and has on'its underside at its rear end (its upper end in Fig.1) a pin or post 36 which has sliding movement in a vertical opening 36a formed in the slide member 30. The front end of the feed dog 35 on its underside is provided with a positioning arm 37 which interfits the groove 34a in the lug 34 of the slide member 30. The feed dog 35 is adapted to operate in an opening formed in the needle plate 16' as will be well understood and said feed dog can readily be operatively connected to the slide member 30 by inserting the pin or post 36 of the dog into the vertical opening in the slide member and by locating the positioning arm 37 of the dog in the groove 34a of the slide member.

A retaining spring 38 has one end fixedly secured to the slide member 30 while its other end is laterally bent and is adapted to engage in a retaining groove formed on the upper side of the feed dog 35 adjacent the rear end thereof and overlying the pin or post'36. *It will be seen that the spring 38 retains the post 36 in the opening in the slide member 30 but that the feed dog while moving with the slide member 30 can have vertical movement relative thereto. It will also be seen that when it is desired to remove the feed dog all that is necessary is to remove the needle plate '16, raise the spring 38 to disengage the laterally extending free end thereof from the retaining groove in the upper side of the feed dog, after which the latter can be readily separated from the slide member 30. Conversely, it'will be appreciated that the feed dog 35 can be readily mounted in operative relationship to the slide member 30. t

A rise and fall actuating arm 39 extends intermediate the rear end of the feed dog 35 andthe upper side of the slide member 30 and this arm is provided witha hub portion that interfits and is fixed to a shaft 40. The shaft 40 is rockably mounted in a suitable bearing opening formed in the block 28 and said shaft 40 extends through the block and beyond theside thereof opposite'to the side at which the arm 39 is located and has fixed to its end or formed integral with its end a feed height regulating arm 41, the free end of which is provided with a transversely widened portion 41a and which on its lower and inner side has a shoulder recess 4112 as clearly indicated in Fig. 3. e

The portion 41a of the arm 41 is provided with a conical opening 42 extending therethrough but with. the horizontalportion of the shouldered recess 41b intersecting saidconicalopening; 4 t A 1'.

Inwardly of the arm 41 a cam follower lever arm 43 has one end rockably mounted on the shaft 40 to rock relative thereto, while its opposite 'end is provided with a downturned cam engaging portion'44. The cam follower arm 43 intermediate its ends and on its vside toward the arm 41 is provided with a laterally projecting lug 45 that interfits the shoulder recess 4117f offithe portion 41a of the arm 41. The upper side of the lug 45 and of the cam follower arm 43 is provided with aconical groove complementary to the underside conical'end or point 46 of a feed dog height regulating rod 47 and which conical end 46 extends through the opening. 42in the portion 41a of the arm 41 and engages in the groove on the upper side of the lug 45 and of the cam follower arm 43.

It will be seen that when the rod 47 is linearly shifted in one direction or the other the conical end 46 thereof will act to raise or lower the arm 41 relative to the cam follower arm 43 and such movement of the arm 41 will rock the shaft 40 so that the lever arm 39 will raise or lower the feed dog 35. The construction of the mechanism for shifting the rod 47 will be referred to herea t v The downwardly extending cam engaging portion 44 of the cam follower arm 43 engages the inclined upper camming face of a cam 48 formed on or secured to the upper end of the vertical shaft 24 which mounts the large drive pulley 25.

The shaft 24 just below the cam 48 is provided with an eccentric or crank portion 49 which is straddled by the forked arm 50 of a substantially T-shaped actuating plate 51. The second arm of the actuating plate'51 and which is in alignment with the arm 50 is indicated at 52 and said armr52 is pivotally connected at 53 to the slide member 30.

The third arm of the T-shaped actuating plate 51 is indicated at 54 and adjacent its free end and on its underside there is pivotally supported a substantially square slide shoe 55 which operates in adiametral slot or channel or groove 56 formed on the'upper side of a disk block 57 that is pivoted on a central axis carried by the wall portion 18 of the sewing machine bed. 7

, The disk block 57 on its circumference is provided with a radially projecting lug 58 to which is connected an end of a stitch lengthand direction adjusting rod 59. It will be noted that therods 47 and 59 actually are formed in two parts which are interconnected by a coupling element'for purposes of adjustment but it shall be sufficient'herein to refer to said

rods

47 and 59 as if they were unitary rods.

The rod 47 is pivotally connected to the lower end of a lever 60 that projects downwardly below the bed plate 15 and upwardly above the bed. plate and into the hollow vertical standard of the head 20 and is pivoted intermediate its ends as indicated at 61. to a block secured to the bed plate 15 within the head 20.

The upper end of the lever60 is forked and straddles a pin 62 carried by a rockable actuating element 63, which, in turn,.is fixed to a horizontal shaft 64 rockably supported in the head 20 and provided at its front end outwardly of the head with an actuating knob 65 provided with a pointer-66 that cooperates with a scale 67 formed on the front side of the head and calibrated in terms of feed height. I

It will be seen'that -rocking'of the knob 65 in either direction rocks the shaft 64 and element 63 and the lever 60 to cause linear movement of the rod 47 in one direction or the other so as to effect various positions ofthe conical point 46 of the rod in the opening 42 of the arm 41 so as to raise or lower said arm 41 relative to the cam follower arm 43 and thus elfect raising or lowering movement of the feedidog 35 to different starting positions from which said dog will have its rise and fall movement imparted thereto by the cam 48 and cam follower arm 43. In this way'the feed dog 35 can be positioned so as never to rise above the upper surface of the needle plate 16 when'it is desired to use the sewing machine as a drop feed machine. Also the amplitude of the rise and fall movement of the feed dog 35 can be changed to cause the teeth of said feed dog to have a maximum raised position above the bed plate that is selectively variable. a V

The rod 59 is pivotally connected to the lower end of a lever 68 that extends below the bed plate and upwardly of the same and extends into the hollow head 20 of the sewing machine and is pivotally mounted intermediate its ends as indicated at 69 on the supporting block that is secured to the upper side of the bed plate within the hollow head and which carries the pivot 61 for the lever 60.

The upper end of the lever 68 is forked and straddles a pin 70 fixed in a rockable element 71 that is secured to a horizontally rockable shaft 72 mounted in the head of the sewing machine and projecting beyond the front side of the machine. The shaft 72 mounts a stitch length and direction adjusting mechanism including a dial 73, a sleeve 74 mounting a pin 75 which cooperates with a V-notch formed in a sleeve-like bushing 76 secured to the front of the head. Also a pointer 77 is operatively associated with the knob 73 and cooperates with a scale 78 formed on the front of the sewing machine head and calibrated in terms of stitch length for both the forward and reverse directions. The stitch length and direction mechanism just hereinbefore briefly described is fully dis closed in my copending application Serial No. 478,775, filed December 30, 1954.

It will be understood that by turning the knob 73 the pin 75 is moved along one wall, i. e., the forward stitch wall of the V-shaped notch in the sleeve bushing 76 to efifect rocking movement of the shaft 72 and movement of the rod 59 and pivotal movement of the disk block 57 to vary the angular position of the slot 56 to obtain different stitch lengths in the forward direction.

It will also be understood that when it is desired to sew in the reverse direction the operator merely swings the pointer 77 from the forward side of the scale 78 to the reverse side thereof and said pin 75 moves straight across the V-notch in the sleeve bushing 76 and the disk block 57 is rocked to position the slot 56 in the same angular relationship but inclined in the opposite direction from its former inclined position.

When the operator turns the knob 65 the rod 47 is moved linearly to raise or lower the arm 41 relative to the cam follower arm 43 due to the conical point 46 of the rod 4'7 which passes through the arm 41 and bears upon the upper side of the cam follower arm 43 which, it will be recalled, is provided with a groove complementary to the lower side of the point 46. Thus the arm 41 is raised or lowered and the shaft 49 is rocked correspondingly so that the arm 39 raises or lowers the feed dog 35 as the case may be. Then when the machine is operating the cam 48 acting on the portion 44 of the cam follower arm 43 will raise and lower said arm and through the pointed end 46 of the rod 47 will raise and lower the arm 41 and rock the shaft 40 and the arm 39 to impart the rise and fall movements to the feed dog 35. Since the starting position of the rise and fall movements of thefeed dog can be adjusted by the rod 47, it will be seen that different height feeding movements of the feed dog can be selected by the operator through the knob 65.

When the disk block 57 is in a position wherein the because the radius between 53 and the axis of the shoe will be at a right angle to the mid-point of the slot 56. As the shaft 24 rotates the eccentric or crank arm portion 49 thereof operating in the forked arm 50 of the plate 51 will rock said plate about the pivot 53 and the shoe carried by the arm 54 of the plate will move in the slot 56 so that the distance between the pivot 53 and the axis of the shoe 55 remains the radius of the swinging movement.

It will be understood that the amplitude of rocking movement imparted to the plate 51 by the eccentric portion 49 of the shaft 24 is such that the shoe 55 will only move relatively short distances to each side of its center position in the 45 slot 56 and even though the shoe is moving on an arc the curvature of the arc is slight and the clearance allowances between the shoe and the walls of the slot can be such as to accommodate the slightarcuate movement of the shoe.

When it is desired to part adjustment to the disk block 57 to provide for a certain stitch length said block is rotated by the rod 59 to position the slot 56,.at an.

angular position relative to the shaft 29 other than the 45 position just referred to as, for instance, the position indicated in Fig. 1 in which the slot is perpendicular to the shaft 29. Then as the eccentric portion 49 of the shaft 24 rocks the plate 51 about the pivot 53 the arcuatemovement of the shoe 55 in the slot 56 is limited by the slot and this causes the slide member 30 to move compensatingly on the shaft 29 and to impart horizontal I movements to the feed dog 35 in opposite directions.

It will be understood that the parts are so related andtimed that the horizontal feeding movement of the feed dog 35 will occur when said feed dog is substantially at its maximum raised position while the horizontal return movement of the feed dog will occur when said feed dog is substantially at its minimum lower position for the various adjusted feed heights.

It will also be understood that different stitch lengths can be obtained by providing different length feeding movements of the feed dog by setting the disk 57 in various adjusted positions to have the slot 56 variously inclined with respect to the shaft 29 between the no feed 45 position and the maximum feed perpendicular or 90 position.

It will be understood that when it is desired to impart reverse feeding movement to the feed dog the disk 57 is turned so the slot 55 will be located in the oppositely inclined positions.

In Figs. 7 and 8 a feeding mechanism embodying the. invention is illustrated and said mechanism is identical with the mechanism shown in Figs. l to 6 inclusive, except that the actuating plate of Figs. 7 and 8 is an L-shaped plate as distinguished from the T-shaped plate 51 shown In Figs. 7 and 8, as stated above, an L-shaped actuating plate 79 is employed and this plate includes the arm 80 having the fork that cooperates with the eccentric portion 49 of the shaft 24 and an arm 81 extends substantially at right angles to the arm 80. The plate 79 is pivotally connected at 82 to the slide member 30 and this point of pivotal connection is substantially at the junction of the

arms

80 and 81. This free end of the arm 81 rotatably mounts a roller shoe 83 that operates in the slot 56 of the disk block 57. It will be noted that when the pivotal axis of the roller shoe 83 is midway of the slot 56 it and the pivot 82 are located in a line parallel to the shaft 29. In the construction of Figs. 7 and 8 when the slot 56 is at right angles to the shaft 29 then the actuator plate 79 will rock about the pivot 82 without imparting any horizontal reciprocating movement to the feed dog 35. This is so because the roller shoe 83 although moving in an arc has such a fit in the slot 56 that it can move in said slot when the latter is perpendicular to the shaft 29 within the limits of the amplitude of rocking movement of the plate 79 without exerting any camming reaction force against the wall of the slot which would cause shifting movementof the slide. However, to effect horizontal reciprocating movement of the feed dog 83, the slot 56 can be angularly positioned relative to the shaft 29 other than at a right angle thereto by the turning of the disk block 57 through the rod 59, and consequently the movement of the roller 83 in the slot 56 as the plate 79 oscillates causes the roller to exert a camming reaction against the walls of the slot 56 and the slide member 30 will move to compensate for this camming force and hence a horizontal reciprocating movement will be imparted to the feed dog 35. Itwill be understood that inclination of the slot 56 to opposite side of its perpendicular position effects either forward or reverse feeding movements.

straight slot 56 is employed. In Fig. 9 the slot 84 when in the full 'lineposition causes no feeding movement to be imparted to the feed dog since the plate 79 merely oscillates, on the pivot 82 and the roller 83 idles in the slot. In Fig. 9 when the disk block 57 is turned so that the slot 84 is positioned in the broken line position then a feeding movement will be imparted to the feed dog 35 and the amplitude of such movement will depend on how far the block 57 was turned from the position wherein the slot 84 is in the full line position of Fig. 9. Of course for reverse feeding the block 57 would be turned in the opposite direction.

In Figs. and ll a feeding mechanism embodying the invention is illustrated and which differs from the previously described forms with respect to the type of actuator plate employed in the mechanism. insofar as the parts are identical in Figs. 10 and 11 with the parts of the previously described forms the same reference characters are used'and the description of such parts need not be repeated.

In Figs. 10 and 11 the actuator plate is indicated at 85 and said plate is of rectangular-configuration and at one endis provided with a forked portion 86 that straddles the eccentric portion 49 of the shaft 24. The underside of the plate 85 is provided with a longitudinally extending groove87 that projects to the end of the plate opposite to the forked end thereof. The plate 85. is pivotally connected at88 to the slide member but this does not constitute the fulcrum point'for the oscillating or rocking movement imparted to the plate by the eccentric portion 49. The fulcrum point for the oscillating movement of the plate 85 is the axis of a roller shoe 89 located in the groove 87 and carried by a slide bar 90 to which the rod 59 is connected. 7

It will be seen that the amplitude of movement imparted by the plate 85 to the slide 30 depends on the location of the roller 89 lengthwise of the groove 87 and therefore the adjustment of the roller will provide for dilferent stitch lengths. Also the reversing of the feed movement of the feed dog can be aocomplished by moving the roller .89 in the groove 87 to the opposite side of the pivot 88 from that in which it is shown in Fig. 10.

v Instead of the

shafts

22 and 24 having the belt driven toothed pulleys 23 and 25 fixed thereto in Figs. 10 and 11 said

shafts

22 and 24 have fixed thereto gears 93 and 92 with the latter twice the size of the gear 91. The shaft 24 below the gear 92 mounts a driving pulley 93 which is rotated by a driving belt 94. The pulley $3 is secured to the shaft 24 by an internal setscrew arrangement comprising radially movable pins 95 carried by the shaft 24 and spread apart into tight engagement with the wall of the central opening in the pulley 93 by the conical end of a clamping screw 96 screwed into a threaded axial bore formed in the shaft 24.

Although a number of embodiments of the invention have been illustrated and described herein it will be understood that theinvention is susceptible of various modifications and adaptations within the scope of the appended claims.

- Having'thus described my invention, I claim: l. A feed mechanism for a sewing machine comprising thesewing machine bed including a bed plate and supporting structure beneath said bed plate, a slide supported by said structure for linear reciprocating horizontal movement transversely of the bed, a feed dog carried by said slidefsaid feed dog and said slide having cooperating means whereby said dog moves linearly with said slide but'is capable of vertical movement relative thereto, separate meansfor vertically movingrsaid feed dog relative to said slide and for linearly reciprocating said slide, and

means for actuating the said separate means in timed relationship, the means for vertically moving said feed dog including means for varying the vertical relationship be tween said slide and feed dog to change the starting point of the vertical movement of the latter.

'2. A feed mechanism as defined in claim 1 and wherein said means for linearly reciprocating said slide includes means for varying the amplitude of the reciprocating movement.

3. A feed mechanism as defined in claim 1 and wherein said means for vertically moving said feed dog and said means for linearly reciprocating said slide include separate means for varying the terminal location of the vertical movement of the feed dog relative to the base plate and for varying the amplitude of the reciprocating movement of the slide.

4. A feed mechanism as defined in claim 1 and wherein said means for reciprocating said slide includes means for varying the amplitude of the reciprocating movement and for reversing the phase thereof to obtain variable feeding movement of the feed dog in the forward or reverse direction.

5. A feed mechanism as defined in claim 1 and wherein said means for reciprocating said slide includes a rockable member operatively connected to said slide and to said actuating'means.

6. A feed mechanism as defined in claim 5 and wherein said rockable member has angularly disposed arms, one of which is operatively connected to said actuating means and another of which carries a pivoted shoe engaging in a slot formed in a rotatablyadjustable member.

7. A feed mechanism as defined in claim 6 and wherein said rockable member is substantially T-shaped with one end of its cross arm 'pivotally connected to said slide and the other end thereof operatively connected to said 8. A feed mechanism as defined in claim 6 and wherein said rockable member has two arms disposed at right angles to each other, the free end of one arm being operatively connected to said actuating means and the free end of the other arm mounting said pivoted shoe that engages in said slot of said adjustable member, said rockable member being pivotally connected to said slide at the junction of said two arms.

9. A feed mechanism as defined in claim 5 and wherein said rockable member is operatively connected to said actuating means adjacent one of its ends and is pivotally connected to said slide adjacent to but inwardly of its opposite end, said rockable member being provided with an elongated groove on its longitudinal center line extending from just inwardly of its operative'connection to said actuating means past its pivotal connection to said slide, and means adjustable longitudinally of said groove and including a roller mounted in said groove and constituting the fulcrum about which said rockable member rocks.

10. A feed mechanism for a sewing machine comprising the sewing machine bed including a bed plate and supporting structure beneath said plate, a slide supported by said structure for linear reciprocating horizontal movement transversely of the bed, a feed dog carried by said slide, said slide and said feed dog having cooperating means whereby said dog moves horizontally with said slide but can have vertical movement relative thereto, means for linearly reciprocating said slide, means for vertically moving said dog relative to said slide, means for actuating the last two named means in timed relationship, said cooperating means on said dog and said slide including a vertical recess in said slide adjacent one end thereof and a groove on the upper side of said slide adjacent the opposite end thereof and extending transversely of the bed, said cooperating means further including a pin on the underside of said feed dog adjacent one end thereof engaging in said recess and a positioning arm on the other end of said feed dog engaging in said groove, and spring means carried by said slide and engaging said feed dog and acting to maintain the feed dog assembled with the slide but permitting vertical movement of the feed dog relative to the slide.

11. A feed mechanism as defined in claim and wherein said slide is provided with a laterally extending arm engaging in a groove carried by said supporting structure and extending transversely of the bed, said arm and groove acting to prevent rocking movement of said slide.

12. A feed mechanism for a sewing machine comprising the sewing machine bed including a bed plate and supporting structure beneath said plate, a horizontally fixed shaft carried by said supporting structure and extending transversely of the bed, a slide supported by said shaft for linear reciprocating movement therealong and for rocking movement about the axis of said shaft, said slide and supporting structure having cooperating means preventing rocking movement of said slide, a feed dog carried by said slide for movement therewith when said slide reciprocates but capable of vertical movement relative to said slide, means for reciprocating said slide, means for vertically moving said dog relative to said slide and including a rockable arm extending-between said slide and dog, and means for actuating the last two named means in timed relationship.

13. A feed mechanism as defined in claim 12 and wherein said means for vertically moving said feed dog relative to said slide includes a rockable shaft carried by said supporting structure and having fixed to one end thereof said rockable arm and to the other end thereof a second rockable arm, an actuating arm freely rockable on said rockable shaft adjacent said second rockable'arm and having a portion operatively engageable with said second arm, and means for actuating the slide reciprocating means and the means for vertically moving said feed dog and including a rotatable vertical shaft carried by said supporting structure and mounting on its upper end a cam acting on said actuating arm to impart rocking movement thereto and to said rockable shaft to produce vertical movement of said feed dog.

14. A feed mechanism as defined in claim 13 and wherein means is provided for adjusting the operative relationship between said second rockable arm and said actuating arm to vary the starting point of the vertical movement of said feed dog.

15. A feed mechanism as defined in claim 13 and wherein said vertical shaft below said cam is provided with an eccentric portion while said means for reciprocating said slide-includes a rockable member operatively connected to said slide and having a portion straddling said eccentric portion of said vertical shaft.

16. A feed mechanism as defined in claim 15 and wherein said rockable member has angularly disposed arms, one of which at one of its ends operatively straddles said eccentric portion of said vertical shaft and is operatively connected to said slide at its other end and another of which carries a pivoted shoe engaging in a slot formed in a rotatably adjustable member.

17. A feed mechanism as defined in claim 15 and wherein said rockable member is substantially T-shaped with one end of its cross arm being pivotally connected to said slide and the other end thereof straddling in operative relationship said eccentric portion of said vertical shaft and the free end of its leg carrying a pivoted shoe that engages in a slot formed in a rotatably adjustable member.

18. A feed mechanism as defined in claim 15 and wherein said rockable member has two arms disposed at right angles to each other, the free end of one arm operatively straddling the eccentric portion of said vertical shaft and the free end of the other arm mounting a pivoted shoe that engages in a slot formed in a rotatably adjustable member, said rockable member being pivotally connected to said slide at the junction of said two arms.

19. A feed mechanism as defined in claim 15 and wherein said rockable member extends longitudinally of the bed and is provided at one end with a forked portion operatively straddling said eccentric portion of said vertical shaft and is pivotally connected to said slide adjacent to but inwardly of its opposite end, said member being provided on its center line with a longitudinal groove extending from inwardly of its forked portion to said opposite end of the member, and means adjustable longitudinally of said groove and including a roller engaging in said groove and constituting an adjustable fulcrum for the rocking movement of said rockable member.

References Cited in the file of this patent UNITED STATES PATENTS 2,442,647 Fischbein June 1, 1948 2,638,068 Gottlieb et al. May 12, 1953 2,725,023 Ayres Nov. 29, 1955 FOREIGN PATENTS 91,830 Switzerland Dec. 1, 1929 248,051 Switzerland Nov. 1, 1952 706,073 Great Britain Mar. 24, 1954