US2550553A - Feeding mechanism for sewing machines - Google Patents

Description

April 1951 D. A. GRAESSER ET AL I 2,550, 3

FEEDING MECHANISM FOR SEWING MACHINES Filed march 24, 194s -s Sheets-Sheet 1 IN V[ N 7038 q Daw'ciA.G9aesser am? WITNESS I w By flozi/oi y JWalwzas 7f fwya a WM A TTOAZ/VB/ D. A. eRAlzssEh ET AL "FEEDING MECHANISM FOR SEWING MACHINES Filed March 24, 1948 April 24, 1951 3 Sheets-Sheet 2 //VV[/VTOBS v DavzdA. Gwaesser mid B manycl Wiazfuzas ATTORNEY April 24, 1951 D. A. GRAESSER ET AL FEEDING MECHANISM FOR SEWING MACHINES Filed March 24, 1948 3 Sheets-Sheet I5 s w w w, .w 6 a 7 09d aha a5 w ,w m a T: 5 V 6 6 w a w WITNESS work-advancing stroke.

UNITED STATES PATENT OFFICE.

V FEEDING MECHANISM FOR SEWING MACHINES David A. Graesser, Westfield, and Anthony J.

Matuzas, Union, N. J., assignors to The Singer .Manufacturing Company, Elizabeth, N. 'J., a

corporation of New Jersey 7 Application March 24, 1948, Serial No. 16,796

This invention relates to feeding mechanisms for sewing machines and it has as an object to provide an improved four-motioned feeding mechanism capable of being embodied in a relatively small cylindrical Work-supporting arm.

Another object of the invention is to provide an improved four-motioned feeding mechanism of this nature in which the feed-driving mechanism and the feed-lift mechanism are so constructed and coordinated that the feed-dog is 7 moved in a plane substantially parallel to the upper face ofthe throat-plate during its entire Another object of the invention is to provide animproved feeding mechanism in which the feed-bar is guided to move in vertical and horizontal planes without objectionable friction and in which the feed-drive and feed-lift mechanisms transmit their respective. motions tothe feed-bar without anyangular' distortion. Another object of this invention is to provide a feeding mechanism having a feed-bar mounted for vertical and horizontal sliding movements and in which feed-lift and feed-drive movements are transmitted to said feed-bar by feed-lift and feed-drive rock-shafts through the medium of freely swinging vertically and-horizontally disposed links, respectively. v

A still further object of the invention is to provide a four-motioned feeding mechanism having improved manually actuated means for rendering the feeding mechanism ineffective to feed the work by dropping the feed-dog below the upper surface of the throat-plate to facilitate manual shifting of the work, as when embroidering,'darning, etc. e r

Still another object of the invention is to provide, in a feeding mechanism having a feeddrive mechanism and a feed-lift mechanism, means for shifting the feed-dog to a position wholly below the upper surface of the throatplate and for simultaneously therewith rendering the feed-lift mechanism ineffective to lift the feed-dog.

Withthe above and other objects in view, as will hereinafter appear, the invention comprises the devices, combinations, and arrangements of parts hereinafter set forth and illustrated in the accompanying drawings of a preferred embodiment of the invention, from which the several features of the invention and the advantages attained thereby. will be readily understood. by those skilled in the art.

:In the. drawings, Fig. 1 is a longitudinal vertical sectional view of awsewing machine embody- 17 Claims. (01. 112-210) 2 V ing the present invention, with certain ones of the parts shown in elevation. Fig. 2 is an enlarged transverse vertical sec= tional View taken substantially on the line 2-2 of Fig. 1. i

Fig. 3 is an enlarged central vertical sectional view of the free end portion of the work-supporting arm and the improved feeeding mechanism therein, the loop-taker shaftand the loop-taker thereon being shown in elevation; a

1 Fig; 4 is-a'bottom view of the machine shown in Fig. l with parts of the bed and the work-supporting arm broken away.

Figs. 5 and 6 are vertical sectional views taken substantially on the lines 5-5 and 66, respectively, of Fig. 1. r a

v Fig. 71s a detail vertical sectional view taken substantially on the line 1-'l of Fig. 1. 5

Fig. 8 is a detail sectional view taken substantially on theline 88 of Fig. 2.

Fig. 9 is a disassembled perspective view of certain elements of the present improved feeding mechanism, hereinafter to be described.

Figs. 10 and 11 are diagrammatic views,in two positions, of portions of the feed-lift mechanism and the means for dropping the work-engaging portion of the feed-dog below the upper surface of the throat-plate and for rendering the feed lift mechanism ineffective to raise the feed-dog. Referring more specifically to the drawings, the invention is disclosed as embodied in a sewing machine comprisinga frame including an inverted box-like base I to which is secured a horizontally disposed cylindrical work-supporting arm 2. Secured upon the upper side of the base i is a-sewing machine-head comprising a. standard 3; and an overhanging I bracket-arm 4 which terminates in a vertically disposed bracket-arm head 5. Journaled horizontally in the bracket-arm in' bearings 6 and l is a main or needle-bar driving shaft 8 to the rear end. of which is secured a combined belt and hand wheel 9, by means of'which the shaft is rotated from any suitable source of power. Mounted in bearings l0 and H in the bracket-arm head 5 is'a reciprocating needle-bar I2 which carries, at its lower end,-an eye-pointed thread-carrying needle I3. The needle-bar is reciprocatedfrom the shaft 8 through the medium of a crank-disk l4 secured upon the-shaft, acrank pin l5 carried by the disk, and a link l6 connecting the crankpin' with a stud carried by a collar I'Isecured upon the needle-bar. The bracket-arm head also carries the usual spring-depressed'presserf bar Is to the lower end of which is secured'a con ventional work-engaging presser-foot I 9 adapted to cooperate with a feeding mechanism, hereinafter described, to effect step-by-step feeding movements of the work.

Cooperating with the needle in the formation of stitches is a rotary loop-taker 20, which, in the present case. is of the rotary hook type having a needle-thread loop seizing beak 2|. The loop-taker has journaled therein a bobbin-carrier 22 Which is retained against rotation with the loop-taker by its engagement with stop shoulders. as 23, carried by the under side of a slotted throat-plate 24, secured to the upper portion of the arm 2, adjacent its free end.

The loop-taker 29 is secured upon one end of a rotary loop-taker shaft 25 journaled, adjacent its forward end, in a bearing member 26 secured in bearing bosses 2 and 2 depending from the upper wall of the arm 2 and, at its rear end, ina bearing 21 provided by the base I. The looptaker shaft 25 is rotated from the main shaft 8 through the medium of a pair of bevel gears 28, 29,. which drive a shaft 30 journaled vertically in the standard 3, and a second pair of bevel gears 3|, 32 of which the former is secured upon the shaft 39 and the latter upon theloop-taker shaft 25. The ratios of the gears 28, 29 and 3|, 32 are such that the loop-taker shaft and the loop taker carried thereby are given two rotations for each rotation of the main shaft 8 and consequently two rotations for each reciprocation of the needle-bar.

An improved four-motioned feeding mechanism, now to be described, is provided for advancing the work once for each reciprocation of the needle. This feeding mechanism comprises a feed-dog 33 having serrated work-engaging portions which operate through slots in the throatplate 24. The feed-dog is secured, as by screws 34, to the flat upper surface 35 of a vertically disposed, ring-like supporting member 35, hereinafter called the feed-bar, which surrounds the bearing member 26 and is given'rising and falling movements from a feed-lift rock-shaft 36 journaled lengthwis within the work-supporting arm 2on pintles 31 and 38 secured in the machine frame. The feed-bar 35 and the feed-dog 33 carried thereby are also given'feed and return movements, from a feed-drive rock-shaft 39 journaled lengthwise within the arm 2 on pintles 40 and 4|, also-secured in the machine frame.

7 Secured upon the main shaft 8 is-a feed-drive cam 42 which rotates between the spaced walls 43 of a fork 43- formed at the upper end of a pitman 44. At its lower end, the pitman 44- is pivotally connected, at 45, to one end of a rockarm 46, the other end of which is secured upon the feed-drive rock-shaft 39, as by pinchjoint 41. Adjacent its upper end, the pitman 44 carries a roller stud 49 which tracks a channel 49 formed in a guide-block 49 mounted, for angular adjustment, on a screw stud 50 supported by the standard 3. The block 49 carries a handle. which projects through. a slot 3 in the forward wall of the standard 3. With the parts in the positions shown in Fig. 2-, back and forth oscillation of thepitman 44, about the pivot 45, by the cam 42, will cause the roller stud 48 to ride up and down in the inclined channel 49 thereby translating the back and forth movements of the pitman into endwise reciprocations. These end wise movements of the pitman cause the rockarm 46 and the feed-drive shaft 39 to-be oscillated about the axis of thatshaft. These oscillations transmit feedand return movements to the feeddiseases bar 35 and the feed-dog 24 carried thereby, by mechanism hereinafter described. The portion of the feed-drive mechanism above described is conventional and forms no part of this invention. As is well understood, the amount of endwise movement transmitted to the pitman 44 by the stud 48 and block 49 and consequently the length of feed stroke of the feed-dog 24, is dependent upon the angular setting of the block. By shifting the handle 5| upwardly from its lowermost position to a mid-position the feed stroke may be reduced from maximum to zero. Likewise by shifting the handle upwardly above its mid-position the angular position of the block 49 and channel 49 may be inclined in the direction opposite to that shown in Fig. 2 thereby effecting a reverse feed.

The means for giving to the feed-bar 35 and feed-dog 24 their rising and falling movements, in synchronism with their feed and return movements, comprises an eccentric 52 secured upon the main shaft 8, adjacent the feed-drive cam 42. This eccentric is surrounded by the strap end 53 of a pitman 53. At its lower end, the pitman 53 is pivotally connected, by a stud 54, to the upper end of a link 55-, the lower end of which is pivoted, by studscrew 56, to the free end of a rockarm 51 secured, by pinch joint 58, on the feedlift rock-shaft 36. The stud 54 carries a roller 59 which tracks a channel 69 formed in a tiltable guide-block 6|] integral with a shank 6| journaled in boss 62 depending from the uper wall of the base The shank 6| and block are frictionally retained in their adjusted positions by-a friction washer 63 interposed between the boss 62 and a nut 64 threaded on the shank. A hand lever- 65 secured on the shank 6|, between the nut 64 and a second nut 66, serves as means for angularly adjustin the block 60.

With the parts in the positions illustrated in Figs. 1, 2 and 10, endwise reciprocations of the pitman 53, under the influence of the eccentric 52, causes the roller 59 to. ride up and down in the channel. 6|] at an angle of approximately 30 degrees to the vertical, as represented by the arrow a in Fig. 10. These movements shift the link 55 endwise, as represented by arrow b, which, in turn, oscillate the rock-arm 5'! and feed-lift rockshaft 36-, as indicated by the arrow 0.

From the foregoing, it will be understood that, with the parts in the positions shown in Figs. 1, 2 and 10,. rotation-of the shaft 8 will effect oscillatory motions in the feed-lift shaft 36 and the feed-drive shaft 39-. These oscillatory motions are transmitted to the feed-bar 35, and to the feed-dog 33 carried thereby, through the medium of directly acting endwise movable links which give to the feed-bar vertical rising and falling movements and horizontal feedand return movements. 7

Asshown most clearly in Figs. 1, 3 and 9, the stationary bearing member 26, for the loop-taker shaft 25, is formed, at one end, with a stationary guide member'in the form of a disk or flange 26 provided with diametrically opposed vertically arranged slots 26 and 26 and a flattened and beveled upper edge 26 Surrounding the bearing member 26, and in engagement with the rear face of the disk 26*,is, a flat ring-like slide member 67 having forwardly projecting lugs 61*, 61 which are slidingly received in the slots 26 and 26,respectively, in the disk 26 The slide member 67 is formed with a relatively large central aperture 6! which affords suficient clearance around; the bearing member 26: to. permit the slide member to partake ofthe' verticalmove ments of the feed-bar. x At its rear side, the slide member 61 carries lugs til and fi'l which are,

slidingly fitted within horizontally arranged slideways 35. and 35 respectively, formed in the feedbar 35. The feed-bar 35 also has a relatively large central aperture 35 which affords sufficient clearance around the bearing member 26 to permit the feed-bar to be given vertical feed-lift and'horizontal feed-drive movements. The forward vertical face of the feed-bar is held in contact with the rear vertical face of the slide member 6'! by a stationary guide plate 68 which surrounds the bearing member 26 and which is held posed pins 14 and 15 connected, respectively, to the-feed-lift and feed-drive mechanisms.

pinfl-d passes through an aperture [58 in. the .plate 68. The upper edge, of the plate. 68 is formed with a cut-out 68' which affords clear- The ancefor the pin 15; Journaled on the pin 14 is the lower end of .a vertically disposed feed-lift link 16 the upper end ofwhich is pivotally connected, by a bolt 11, withthe free end 18 of a rock-arm 1B integral with the feed-lift rock- .shaft 36.

The pin 15, which projects fromthe feed-bar .35, has pivotally mounted thereon one end of a horizontally disposed feed-drive link '19 the other .end of which is pivotally connected, by a bolt 80 with the upper free end 8W of an arcuate rockarm 3| integral with the feedvdriverock-shaft 39. i From the foregoinglit will be understood that the feed-bar 35 and the slide member 61 are mounted for simultaneous vertical movement between the flange and the plate: 68, while the feed-bar is mounted for independentfhorizontal movement between the slide member. .61 and the plate 68; The feed-lift link 16 and, the feed-drive link 19 are connected to the feed-bar 35, and transmit feed-lift and feed-drive movements directly to the'feed-bar without any binding or any angular distortion. Inasmuch as the member 61 isfree to float with the feed-bar the vertical and horizontal-guideways 26 .26 and 35 serve to orient the feed-bar but in no way deter,-

mine the path ,of movement of a point on the feed-bar, this'being directly determined by the characteristics of the linkage and the actuating .means therefor. i

; Themeans for dropping the feed-dog and for maintaining the work-engaging teeth gthereofbelow-the work-supporting surface of the throat-.-

in Figs. 1 2 and 10, rotation of the main shaft 3 and the eccentric 52 thereon will effect endwise reciprocations of the pitman 53 which, in turn, through the guide block 60; link55 and rock-arm 51, will oscillate the feed-lift rock-shaft and cause the rock-arm l8 and link 16 to raise :and lower the feed-bar'35 and the feed-dog 33 secured thereto. When it is desired todrop the feeddog and to discontinue its rising and falling movements, the operator shifts the hand lever 6 5 rearwardly to the position illustrated in Figs. =7 and 1-1. This causes the guide-block fiflto be i plate will. now be described. As hereinbefore stated, with the parts in the positionsillustrated turned about its pivot 6|, which-as shown mast clearly by Figs. 8 and 10, is located more closely to the upper end of the block 60 than to the lower end thereof. This turning movement of the block 60 shifts the link 55 upwardly to the position shownin full lines in Fig. 11. This upward endwise movement of the link 55 turns the rockarm 51, rock-shaft 36 and rock-arm 18 clockwise about the axis of the rock-shaft thereby dropping the link 16, feed-bar35 and feed-dog 33: from the. position shown in dotted lines in Fig. 11 to the position shown in full lines; The feed-bar and the feed-dog are maintained in this lowered position so long as the .hand lever 65 is retained in theposition illustrated in Figs. x'land 11; In this position of the .parts, endwise-re-.

ciprocation of the pitman 53, under'the influence of the eccentric 52, causes the stud 59 to be shifted back and forth in the channel 64 inthe block 60, as represented by the arrow a. Inasmuch as this movement is of limited extent and is subtion, what we claim herein is:

1. A feeding mechanism for sewing machines comprisingavertically disposed feed-bar; a feeddog secured to saidfeed-bar; means connected directly tosaid feed-bar for supporting said feedbar and for giving to it feed-drive and feed-lift movements; a guide member engaging one'face of said feed-bar; and an interfitting slidingconnection between said feed-bar and said member for guiding said feed-bar in its horizontalfeed and return movements.

V 2. A feeding mechanism for sewing machines comprising a rotary drive shaft; a vertically disposed feed-bar; a feed-dog secured to said feedbar; means actuated by said drive shaft and connected directly to said feed-bar for supporting said feed-bar and for giving to it feed-drive V and feed-lift movements; guide members engagingthe opposite faces of said feed-bar; and an 'interfitting sliding connection between saidfeedbar and one of said members for guiding said feed-bar in its horizontal feedand return-move ments.

. 3; A feedin comprising a rotary drive shaft; a vertically disposed feed-bar; a feed-dog secured to said feedb ar; means actuated by said drive shaft and connected directly to said feed-bar for supporting said feed-bar and for giving to it feed-drive and feed-lift movements; a stationary guide member horizontally spaced from said feed-bar; a movable guide member disposed between the opposed faces of said feed-bar and said station ary guide member; an interfitting sliding con nection between said movable guide member and said stationary guide member for constraining said movable guide member to move in a predetermined right-line direction; and an interfitti'ng sliding connection between said movable guide member and said feed-bar for constraining said feed-bar to move relativeto said movable guide member ina predetermined right-line direction which is disposed at right angles to the first men 15 bar {means including horizontally and vertically mechanism for sewing machines iii'sposedlinlcs -ractuated from said drivezshaft connected :to saidiifeed-bar :for supporting said 'feedebar and-for giving itoiitifeednrive aandfeedslift movements; astationary guide member horizontally spaced from saidifieed-bmt; :a movable :guide :member disposed .between the opposed faces nfisaid feed-:bar and .saidstationary guide member; an interfitting sliding econnection betweensaid movable guide. member and said sta- .tionaryr-guide memberior. constraining said-movable guide member :to :move :ina predetermined might-line direction; and tan :interfitting z'sliding aconnection between said :movableiguide imember sand. saidfeedbarior constraining said feedebar to zmove relative .to: said movable or guide :member in. a. predetermined zcighteline direction which .is :disposed 13113 .iright .angles to the first-mentioned idirection.

i banal feeding mechanism forisevving machines comprising arotary'drive shaft; a .feedebar -havingmhorizontally disposed guidersurface; a feedrlogzsecured to said :feed-bar; :means actuated byssaid drive shaft .and connected .to :said'feedbanforsupporting :saidlfeedv-bar and for giving to itieed-drive. and feedelift movements; a stationary guide plate :engagingnne face of said feed-bar; and a slide imember engaging the .opposite face of said feed-barandihavingi'aiportion :complemental to the guide surface .of said .feed- .bar (for: guiding said .feed bar :its horizontal feed and return movements. a .r 6. Afeeding "mechanism for sewing machines comprising a rotary drive shaft; a feed-bar :havinghorizontally disposed iguide surfaces; a'feed- .dog secured to said'feed-bar; meansactuated by said drive shaft and connectedydirectly to said feed-bar forgiving to the feed-bar its feed-drive and feed-lift movements; avg-uiderplate engaging one face of said feed-bar; aslide member engaging the opposite face of said feed-bar; and horizontallydisposed guide surfaces provided by said slide member and engaging the guide surfaces "of said feed-bar to guide the feed-bar during its feed and return vmovements. ,7. A feeding mechanism for sewing machines comprising a rotary drive shaft; a vertically disposed-f eed-bar; a feed-dog secured'to saidfeedbar means actuatedby saidd-rive shaft and connected directly with said feed-bar iorsu-pporting the feed-bar and for giving to it feed-drive and feed lift movements; first and second guide membershaving theiriinner faces engagingthe opposite faces of said feed-bar, the first one of said members being stationary and the second being slidingly connected horizontally to said feed-bar -to-guide the feed-barin its horizontal movements and to cause said-second 'guidememberto partake of the vertical movements of the [feed-bar; and vertically disposed guide means engaging said second guide member togguide said second guide member in its vertical movements with the feed-bar. v

:8. A feeding mechanism for sewing machines comprising a rotary drive shaft; a vertically disposed feed-bar having a horizontal slideway; a feed-dog secured to said feed-bar; means including vertically and horizontally disposed endwise movable links actuated "by said idriveshaft and connected directly Withsaid feed-bar for supporting the feed-bar and for giving to it"feedlift and feed-drive movements, respectively; first and secondguidemembershavingtheir inner faces, engaging the opposite ifaces of said feed-bar, the first lone'iof :said members .being stationary and. thersecond being providedwit'h a horizontally dispcsed; guide rib fitted within the .slideway in said 'feedbar to :guide the dieedabar in its horizontal movements and 170 cause said secondsguide member to partake of the vertical movements =1of the feed-bar; and vertically {disposed guide means engaging said second guide member to .guidesaid second guide member inits vertical ;movements with the feed-bar.

9. .A feeding mechanism for sewing machines comprising a feed-drive rock-shaft; a :firstrockarm .on :said rock-shaft; .za feed-lift rock-shaft; asecond'rock-arm on said feed-lift rock-shaft; auvertically disposed feed-bar; a feed-dog secured to said feed-bar; a horizontally disposed link. connecting said first rock-arm with said steed-bar; a vertically disposed link connecting said second rock-arm 'with. said feed-bar; =a =movable guide member connected with said feed-bar so :that relative movements therebetween are confined to ar'ight-line direction; and a stationary guide member connected with said movable guide member so that the movements of said movable guide member are confined to a rightline direction which is disposed at right angles to the :firstimentioned direction. I

10. Afeeding mechanism for a sewing'machine 7 having a substantially cylindrical work-supportingarm, comprising-a feed-drive-rock-s'hafit jourrnaled in the lower portion of said WOIk-SHDIEOIt:

:ing arm and substantially mid-vvay betweenthe side walls thereof; .a first rock-armon said rockshait and :having its free end located in the upperxportion of said work-supporting arm; a "feedlift rock-shaft; a second rock-arm on said feedlift rock-shaft; a vertically disposed I"eedbar; a feed-dog :securedto :said feed-bar; -a Zhorizon- *ta-lly disposed link connecting the free-end of said :first rock-arm with said feed-bar; a vertically disposed link connected at its-upper end to thefree end of said second rock-arm and at :its' lower end to said feed-bar; guide members engaging theopposite faces a of said feed-bar, one of said guide'niembers-being constrained'to move vertically; and an interfitting sliding connection between said feed-bar and said-one'of-said'mem- FJJQIS for guiding said feed-bar in its horizontal feed and return movements.

1 1. In a sewing machine, in combination, -a substantially cylindrical work-supporting'arm; a loop-taker shaft bearing secured within said arm and comprising a cylindrical portion extending lengthwise of said arm substantially"centrally thereof and'a transverse flange at oneend of said cylindrical portion; a loop-taker shaft journaled in said bearing; a vertically disposed feed-bar surrounding said shaft bearing; a feed-dog*carried by said feed-bar; a guide member surrounding said shaft bearing and secured-thereto against rotation, said guide member 'bearing against one face of said feed-bar; a second guide member mounted for vertical movement on the flange portion or said shaft bearing and engaging the vother' faceo'f said feed-bar; and a horizontally disposed interfitting guiding connection between said second guide member and said feed-bar.

12. In a sewing =machine, in combination, a substantially cylindrical work-supporting "arm; a loop-taker shaft bearing secured within said arm and comprising a cylindrical portion-extend- .ing lengthwise iofisaid arm substantially centrallyithereo'f and a transverse flange at one endof said cylindrical portion said flange beingprovided with oppositely extending vertically disposed radial slots; a loop-taker shaft journale'd in said bearing :a vertically disposed ring-like feed bar 444 m w ww horizontally disposed interfitting guiding connection between said second guide member and said feed-bar.

1,3. 'In a sewing machine, in combination, a substantially cylindrical work-supporting arm; a loop-taker shaft bearing secured within said arm and comprising a cylindrical portion extending lengthwise of said arm substantially centrally thereof and a transverse flange at one end of said a cylindrical portion said flange being provided with oppositely extending vertically disposed radial slots; a loop-taker shaft journaled in said bearing; a vertically disposed feed-bar surrounding said shaft bearing and provided with a horizontally disposed slideway; a feed-dog carried by said feed-bar; a vertically disposed guide member surrounding said shaft bearing and secured thereto against rotation, said guide member engaging the rear face of said feed-bar; a second guide member engaging the forward face of said feed-bar and having at one face a pair of projecting lugs slidingly fitted within the slots in the flange portion of said shaft bearing and at its opposite face a pair of projecting lugs fitted within the slideway in said feed-bar; and means directly engaging said feed-bar for giving to it vertical and horizontal movements.

14. A sewing machine combining a frame; a rotary drive shaft journaled therein; a slotted throat-plate carried by said frame; a work-feeding mechanism comprising a four-motioned feedbar; a feed-dog secured to said feed-bar and having serrated portions normally operating through the slots in the throat-plate; means actuated from said drive-shaft for giving to said feed-bar feed and return movements; feed-lifting mechanism actuated by said drive shaft for giving to said feed-bar up and down movements in synchronism with its feed and return movements, said feed-lifting means comprising an actuating element on said drive shaft; a pitman connected to said element for endwise reciprocation thereby; a feed-lift rock-shaft connected with said feed-bar; connecting means between said pitman and said rock-shaft for transmitting to the rockshaft oscillatory motions from the endwise recip rocationsof said pitman; and manually shiftable means for rendering said connecting means ineffective to oscillate said rock-shaft and for simultaneously therewith shifting said feed-dog to a position wholly below the upper surface of the throat-plate.

15. A sewing machine combining a frame; a rotary drive shaft journaled therein, a work-feeding mechanism comprising a four-motioned feedbar; a feed-dog carried by said feed-bar; means actuated from said drive shaft for giving to said feed-bar feed and return movements; feed-lift- 1o ing mechanism actuated by said drive shaft for giving to said feed-bar up and down movements in synchronism with its feed and return move- 'ments, said feed-lifting means comprising an actuating element on said drive shaft; a pitman connected to said element for endwise reciprocation thereby; a feed-lift rock-shaft connected with said feed-bar; connecting means between said pitman and said rock-shaft comprising a rock-arm on said rock-shaft; a link pivotally connected at its lower end to the free end of said rock-arm and at its upper end to the lower end of said pitman; guide means acting on the lower end of said pitman to cause it to move in a path to transmit endwise movements to said link thereby to cause it to effect oscillation of said feed-lift rock-shaft; and means to vary the guide means to cause the lower end of the pitman to move in a path substantially tangent to an arc swung from the lower pivotal connection of said link, thereby to discontinue the oscillation of said feed-lift rock-shaft.

16. A sewing machine as set forth in claim 15 in which the guide means which acts on the lower end of the pitman to cause it to move in a path to transmit endwise movements to the link comprises a pivotally mounted guide-block having a slideway and a stud on the lower end of said pitman which tracks said slideway, and in which the means for varying the guide means to cause the lower end of the pitman to move in a path substantially tangent to an arc swung from the lower pivotal connection of the link comprises a manually actuatable hand lever secured to said guide-block and readily accessible to the machine operator.

17. A sewing machine as set forth in claim 15 in which the means which acts on the lower end of the pitman to cause it to move in a path to transmit endwise movement to the link comprises a pivotally mounted guide-block having a slideway, and a stud on the lower end of said pitman which tracks said slideway and is maintained eccentric to the pivot of the guide-block; and in which a' hand lever is secured to said guide-block and serves as means to shift the guide-block to a position in which it renders the pitman ineffective to transmit oscillations to said feed-lift rock-shaft and simultaneously therewith shifts said link endwise thereby to turn said feed-lift rock-shaft to cause it to lower the upper portion of said feed-dog below the upper surface of the throat-plate.

DAVID A. GRAESSER. ANTHONY J. MATUZAS'.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 763,625 Oakes, Jr June 28, 1904 2,247,382 Hohmann et al July 1, 1941 2,305,556 Pinkvoss Dec. 15, 1942 2,442,647 Fischbein June 1, 1948

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