US2787232A - Feeding mechanisms for sewing machines - Google Patents

Description

April 2, 1957 F. PARRY FEEDING MECHANISMS FOR SEWING MACHINES Filed May 26, 1954 my m T a Q m o w S mm. W @a W S A, Q 1 1 m A l r a eti :D: f lu: M Y m B N n@ n, mm. VL #Y m w SY N bw Nw w sw w m m, w.

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Ap 2, 1957( F. PARRY FEEDING MECHANISMS FOR SEWING MACHINES 6 Sheets-Sheet 2 Filed May 2s,` 1954 IN VEN TOR @Fal/1k C'ZU/'I/y BY ATTRNE'Y mm1-ass April 2, 1957 F. PARRY 2,787,232

FEEDING MECHANISMS FOR SEWING MACHINES Filed May 26, 1954 6 Sheets-Sheet 3 INVENTOR. /zmk cfm/W B Y ATTORNEY April 2, 1957 F. PARRY n 2,787,232

FEEDING .MECHANISMS FOR SEWING MACHINES Filed May 26, 1954 6 Sheets-Sheet 4 INVENTOR. rank @21u/(y WITNESS l v BY A TTORNE'Y Filed May 26, 1954 WITNESS awww@ F. PARRY FEEDING MECHANISMS FOR SEWING MACHINES 6 Sheets-Sheet 5 IN V EN TOR.`

Frank Parry Fig A T TORNE Y April 2, 1957 F. PARRY FEEDING MECHANISMS FOR SEWING MACHINES e sheets-sheet l6 Fil-ed May 26, 1954 Fig.7X

mVENToR Frank Parry ATTORNEY United States Patent- FEEDING MECHANISMS FOR SEWING MACHINES Frank Parry, Trumbull, Conn., assignor to The Singer Manufacturing Company, Elizabeth, N. J., a corporation of New Jersey Application May 26, 1954, Serial No. 432,382

12 Claims. (Cl. 112--213) This application is a continuation-impart of application Serial No. 321,801, iiled Nov. 21, 1952, which is now abandoned.

The present invention relates to sewing machines and has for a primary object to provide an improved feeding mechanism therefor.

More specifically, it is an object of this invention to provide an improved means for actuatingthe feeding mechanism in Aa needle-feed sewing machine, and particularly to provide such mechanism lfor use in a sewing machine having a compound feed mechanism.

in a sewing machine having a needle-feed, it is essential for proper stitch-formation to providef actuating mechanism therefor which will preserve the proper timing relation between the feeding stroke of the needle 'and the operation of the other mechanisms of the machine. ln a machine having a compound feed, i. e., yone provided with both a needle-feed 'and a lower feeding mechanism, this timing becomes very critical since the error may cause the needle to lag the lower feeding element at the beginning of the feeding stroke while the play is being taken up and thus destroy the proper timing relationship Ibetween the actuation of, the two feeding mechanisms; the optimum, of course, being when both feeding strokes exactly coincide. The mechanisms heretofore proposed tor the actuation of a needle-feed have used parts so arranged that any errors in the system due to play caused by manufacturing toleran-ces or wear, have 'been multiplied in transmission to the line of feed of the needle. -arccordingly, it is a specific object of the present invention to provide a mechanism for the actuation of a needle-feed which, rather than multiplying the error due to play in the connections, serves to minimize -or reduce the same.

lt is a further object of this invention to provide in a sewing machine a compound feeding mechanism including Ia needle-feed and a lower-feed mechanism which is so constructed and 'arranged as to facilitate the timing and synchronization of the feeding strokes of theneedlefeed and lower-feed mechanisms.

Having in mind the above and other objects that will be evident from an understanding of this disclosure, the invention :comprises the devices, combinations and arrangements ot" parts as illustrated in the presently preferred embodiment of the invention, which is hereinafter set forth in such detail as to enable those skilled in the art readily to understand the function, operation, construction and advantages ofit when Aread in conjunction with the accompanying drawings in which:

Fig. l is a vertical sectional View taken longitudinally of'a sewing machine embodying-the invention.

Fig. 2 is a `top plan View of thesewingmachine illus-` Fig. 4 is a head end elevational Aview on an ,enlargedV scale of the machine oli-Fig. `1, with the lface''plate'in open feed-bar 38 by a rocker 41 carrie-d by ja feed-advance shaftr ICC position and porti-ons of the face plate and bed shown in section.

Fig. 5 is a vertical sectional view on the scale as Fig. 4 taken transversely through the bracket-arm standard of the machine of Fig. l.

Fig. 6 is a vertical sectional View lsimilar to Fig. 1 illustrating a modification of the invention.

Fig. 7 is a vertical sectional view taken transversely through the standard of the machine of Fig. 6.

The sewing machine illustrated in the drawings includes a base or bed 1, from one end of which rises a standard 2 supporting a bracket-arm 3 that overhangs the base 1 and which bracket-arm terminates in a head 4. The end of the head 4 is normally closed by a face-plate 5 pivoted to the head as at 6, and adapted to be held in closed position by a spring catch '7 (Fig. 4). The faceplate, when swung open, exposes the internal mechanism in the head. The upper portion of the `bracket-arm 3 is closed by a cover-plate S pivoted along one edge `to the bracket-arm by hinges 9 and adapted to be held in closed position by a combined thread-guide and latch 10, which forms the subject matter of my copending application Serial No. 321,802, filed Nov. 2l, 1952, now Patent 2,695,581, dated Nov. 30, 1954. A further coverplate 11 closes an laccess aperture in `the front face of the standard 2 and is removably held in place by a Ibolt 12 passing transversely through the bracket-arm as best seen in Fig. 5. Adjacent the point of stitch formation, there is the usual throat-plate 13 together with the slideplates 14 which permit access to the loop-taker mechanism.

A main or arm-shaft 15 is journaled longitudinally of the `bracket-arm 3 in suitable bearings 16 and 17. Secured to that end of the shaft 15 extending through the end wall of the standard 2 is a combined hand-wheel 'and belt-pulley 1S by means of which power is delivered to the machine in `the-usual manner. A ybed-shaft or loopytaker shaft 19 is suitably journaled longitudinally of the bed 1 in depending 4bearing lugs such as 2t) and 21. Power is delivered to the bed-shaft 19 from the armshaft 15 by a belt 22 entrained about a pulley 23 fixed to the arm-shaft and a pulley 24 fixed to the lbed-shaft 19.

The presser mechanism in the illustrated. machine :comprises a presser-foot 2S carried at the lower end of a presser-bar 26 vertically iournaled for longitudinal sliding movement in suitable 'bearing bushings such as 27 secured in the head 4. The presser-bar is urged downwardly by an adjustable leaf spring only the end 2d of which spring 'appears in the drawings and which overlies a lug formed as part of 'a collar 29 secured to the presserbar. The presser-bar 26 is held against turning by a collar secured thereto and having an arm E@ that rides in a slot 31 formed in the end of a bifurcated -rod 32 xed in the head 4 spaced from `but parallel to the presser-bar. To raise the presser-bar 26 there is provided on it a sleeve 33 having a lateral arm 34 extending thro-ugh a slot in the head 4 to where it is adapted to be contacted by a conventional :cam-shaped hand-lifter lever 35 or by appropriate connections (not shown) with a vertical pushrod 36 that may be actuated by a foot-treadle or knee-pad (not shown).

Cooperating with the presser-foot 25 to elect feeding of the work past the stitching mechanism is a feed-dog 37 which forms one element of the compound feeding.

mechanism, the other element being a needle-feed hereinafter described. The feed-dog 37 is actuated preferably through a four-motion cycle and to this end. is secured to a feed-bar 38 to which feed-lift motions are impartedby a fork 39 thereon that straddles aneccentric 40 on the bedshaft 19. Feed-advance movements are imparted to the treatise 42 which lis journaled Vin bear- ings 43 and 44 and oscillated by an adjustable eccentric 45 fixed to the bed-shaft 19 that is, in turn, connected to the shaft 42 by a pitman 46 and crank 47. The above feeding mechanism is s't'lbstantially disclosed in the U. S. patent of Myers, No. 2,128,031, August 23, 1938, and it is not deemed necessary to expand this disclosure in relation thereto.

Acting in conjunction with the above described lower feeding mechanism is a need-lefeed. As will be noted, there is provided a needle-bar l carrying a pair of needles 49 and journaled for longitudinal reciprocation spa-ced bearings 50 formed as part of a carrier frame 51 that is integral with or secured to the end of a needlebar oscillating shaft 52 journaled in suitable bearings 53 in the bracket-arm 3. The other end of the shaft 52 terminates in the bracket-arm 3 above the standard E, to which end there is secured the upper end of a depending rock-lcver 54 that extends substantially vertically through the standard 2. The rock-lever 54 is .made longer than the distance between the shaft 52 and the point of the needle at the elevation of the line of feed and thus the link extends to below the bed-plate 1. At its lower end, the rock-lever 54 is pivotally connected to a short connecting rod or link 55 which, in turn, is pivotally connected to a crank 56 iixed to the feed-advance shaft 42. From the above, it will be seen that as the feed-advance shaft 42 is oscill'ated to impart feeding motion tothe feed-dog 37, a comparable feeding motion will be imparted to the needle-bar.

The needle-bar 48 is reciprocated longitudinally by means of a connecting rod 57 pivotally connected at one end to a hollow arm 5S carried by a conventional counter balanced crank 59 that is secured to the end of the armshaft 15. At its opposite end, the rod 57 carries a transverse pin 60, one end of which is secured to the needle-bar 48 through a collar 61, and the other end of which rides in a slot 62 formed as an integral part of the carrier 51 thus to restrain the needle-bar against rotation.

Cooperating with each of the needles 49 is a rotary hook 63 mounted upon a vertical axis and adapted to be rotated by appropriate connections with the bed-shaft x 19. Since the details of the rotary hooks or the actuan ing means therefor form no part of the present invention, the Idetails of the same have not been set forth. lt will he understood that any suitable known means may be employed, for example, such as disclosed in the patent of Parry, No. 2,476,061, July l2, 1949.

It will be understood that, in the usual manner, the machine is so timed that the needles 49 are in the work when the feeding motion is imparted thereto and that this Afeeding motion is timed to coincide with that of the feed-dog. In addition, the parts are so proportioned that the feed ing stroke imparted to needle i9 will effect a feeding action on the work that is designed to be exactly equal to the feeding action of the feed-dog 37. To accomplish the latter end, it is necessary that the ratio of the distances be# tween the center of shaft 42 to the pivotal axis of the feed-bar 3S at the end of rocker 41 rand the length of crank 56 must be equal to the ratio of the distances between the center of shaft 52,- whieh isthegpivotal axis of the needle, to the point of the needle in the elevation of the line of feed and the length of the rock-lever 54.

Any play at the two pivotal connections between the rock-lever 54, link 55 and crank 56, which may be caused by improper fitting of the parts or wear, would directly reduce the feeding action of the needle, inv `that there would be a lag `as the play isl being takenY up and thus there would be a' delay before the needle would begin its feed.- ing. stroke. The effectof the play in reducing the'feed-- ing action of theneedle can he readily' visualized by noting that iti ldirectly reduces, by means'of the delay as the play is being taken up, the desired arcuate swing transmitted to the lower end of the rock-lever" 54 and thus reduces the oscillation imparted to the shaft 52 and the'arcuate swing imparted tothe needles* Since' the feeding action of I'eedles'isdterlnined by the arcuate S'Wig of tliepi tions of the needles in the line of feed, the feeding action is also reduced. However, the distance from the shaft 52 to the line of feed can be so proportioned with respect to the rock-lever 54 that the effect of the play can be substantially reduced. From an examination of the me chanics involved it willbe evident that if the distance from the shaft 52 to the line of feed is made equal to the lengthl of the rock-lever 54, the play will appear directly in the feeding stroke. lf the distance is made greater than the length `of the rock-lever 5ft, the effect of the play will be multiplied and if the distance is less than the length of rock-lever 54, the effect of the play will be reduced:

Accordingly, in the disclosed device, the rock-lever 54 is made greater than the distance from the shaft 52 to the line of feed so that the effect of the play will be reduced. Having in mind the above referred to required ratio, the crank 56' must also be made greater than the distance from shaft 42 to the pivotal axis of the feed-bar 33 on the rocker 41. Thus, there have been provided mechanical connections fo-r actuating a needle-feed in which the effects of play or any other looseness or inaccuracies is reduced to a minimum, and the performance is, consequently, as nearly as possible to the optimum. This is particularly significant when a needle-feed is used in conjunction with a lower feed.

In yaddition to the above recited advantages, it will be seen that the forces upon the pivotal connections between the rock-lever 54, connecting rod 55 and crank 56, have been reduced to a minimum and thus the wear and consequent destruction of the parts has been reduced to a minimum.` From' the standpoint of working on the machine for assembly, repair or maintenance, the parts are ma'de more readily accessible than has heretofore been the case. Only the txed connection between the shaft 52 and rock-lever 54 is in the closed bracket-arm, while the pivot points are exposed below the bed of the machine.

Lubrication for the mechanisms of the sewing machine includes a lubricant reservoir 64 closed by a cover-mem ber 65 fastened down as by screws ed. A refill aperture 67 is provided through the cover 65. Lubricant within the reseryoirw64 is conducted by means of a wick 63 to a well 69. The wick 68 passes from the reservoir 64 by means of a slot 70 formed in the upper edge of the walls of the reservoir,- which slot is closed by the cover 65. That end of the wick 63 within the well es? is threaded through an aperture in a depending ear 71 of a sheetmetal shutaoif lever 72, and is thus carried by the lever. As more clearly seen' in Fig. 3, the lever 72 is pivoted to the frame of the machine by one of the screws 66 that hold the cover 65 in place. The connection includes a pressure washer that permits pivotal movement of the lever 72, which lever also includes a laterally extending actuating arm 73 that projects outwardly from the frame of tlie machine immediately beneath the cover 8 to a position where it is adapted to be manually grasped and actuated.

The well 69 isf partially filled with a lubricant-absorbent pad 74 that includes an upstanding portion 75 at a subsftantially higher elevation than the remaining portion. The lever 72 is `madeto carry the end of the wick above the greater portion of the pad and into contact only with the upstanding portion 75. Thus, as the lever 72 is moved, the wick 68 is selectively moved into and out of engagement with the padY 74 and controls the flow of lubri* cant from the reservoir 54 to the well 69. It will be understood that', when the wick` 68 is in engagement with the portion 75 of the pad 74, lubricant will ilow into the well 69 and when the wick is not in engagement with thvpad, no lubricant will flow.

Lubricant is directly carried from the well 69 to various portionsY of the machine mechanisms, as to the bearing surfacebetween the armfshaft 15 and the bearing 17V by a radial wick-filled aperture` 76, and to a pivot pin 77 of a falce-upl l`evl'e78` by af wick 79 running through a longitudinal bore in the pin 77. Lubricant from these parts, which is normally provided in excess, drains to the bottom of the head 4 where it settles into a sump 80 from which it is recovered and re-used, as by a wick 81 that conducts it to the upper bearing surface between the needle-bar 48 and carrier 51, and by a wick 82 that conducts it through apertures in the bearings 53 to lubricate the surface between the same and the shaft 52, and then down through the bracket-arm 2 along the rock-lever 5ft to lubricate the pivotal connections between the rocklever 54 and connecting link 55, and between the connecting link 55 and crank 56.

There is illustrated in Figs. 6 and 7 a modification of the invention as disclosed in Figs. l-5. In Figs. 6 and 7 the illustrated machine is substantially the same as that illustrated in Figs. l-S and the corresponding parts are designated by the same reference numerals. The modied elements are designated by the same reference numerals as the corresponding elements of the machine of Figs. 1 5, but qualified by the sub-designation (1.

The modification of the invention illustrated in Figs. 6 and 7 includesv an adjustment eccentric 45a mounted upon the main-shaft and embraced by the strap-portion at one end of a pitrnan 46a. The pitman 46a is arranged generally vertical in the standard 2 and is pivotally connected at itslower end to one arm 47a of a bell-crank lever L secured to the feed-advance shaft 42. The other arm 56a of the bell-crank lever L is pivotally connected by means of the connecting rod or link 55a to the lower end of a rock-lever 54a which is secured to the needlebar-oscillating shaft 52. It will, of course, be apparent that as the main-shaft 15 is rotated, the pitman 46a will be reciprocated by the eccentric 45a to oscillate the bellcrank lever L about the axis of the shaft 42. Oscillation of the bell-crank lever L will impart oscillation to the feed-advance shaft 42 which will, in turn, impart feedadvance motion to the feed-dog 37. In addition, oscillation of the bell-crank lever L will, through the arm 56a thereof and the connecting rod 55u oscillate the rocklever 54a and the needle-bar oscillating shaft 52 which will impart feeding action to the needle-bar.

The present modification of the invention is of particular advantage in that it facilitates timing and synchronization of the feeding mechanisms. It will be apparent that the timing of either of the needle-feed or the lower-feed mechanisms relative to the shaft 42 will automatically time the other because of the common driving element in the bell-crank lever L.

Numerous alterations of the structure herein disclosed will suggest themselves to those skilled in the art. However, it is to be understood that the present disclosure relates to a preferred embodiment of my invention which is for purposes of illustration only and not to be construed as a limitation of the invention. All such modifications which do not depart from the spirit of the invention are intended to be included within the scope of the appended claims.

Having thus set forth the nature of the invention, what I claim herein is:

l. In a sewing machine having a work-supporting surface, needle-feed mechanism including a needle-oscillating shaft spaced from said work-supporting surface, actuating means for said shaft including an oscillating element movable about an axis parallel to said shaft, and means for connecting said element to said shaft including a rock-lever fixed to said shaft and operatively connected to said element to impart oscillation to said shaft upon oscillation of said element, said rock-lever extending from said element to said shaft a distance at least substantially as great as the distance from said shaft to said work-supporting surface.

2. In a sewing machine having a work-supporting surface, needle-feed mechanism including a needle-oscillating shaft spaced from said work-supporting surface, an actuating shaft arranged parallel to said needle-oscillating avanzan shaft, means for imparting oscillation to said actuating shaft, means for operatively connecting said actuating shaft to said needle-oscillating shaft to impart oscillation to the latter upon oscillation of the former, said lastmentioned means comprising a crank secured to said actuating shaft and a rock-lever secured to said needleoscillating shaft and operatively connected to said crank, said rock-lever extending from the point of connection to said needle-oscillating shaft a distance at least substantially as great as the distance from the axis of said needleoscillating shaft to said work-supporting surface.

3. In a sewing machine 'having a work-supporting surface, a needle-feed mechanism including a needle-oscillating shaft vdisposed above said work-supporting surface, a lower feed mechanism disposed below saidl work-supporting surface, means for imparting feed-advance movements to lsaid lower feed mechanism including an oscillating feed-advance shaft, and means for imparting feed-advance movements :to said needle-feed mechanism comprising a crank carried by said feed-advance shaft and means for connecting said crank to said needle-oscillating shaft including a rock-lever operatively connected to said crank and secured to said needle-oscillating shaft, the point of connection to said rock-lever being at least substantially as low as the plane of said work-supporting surface.

4. ln `a sewing machine having a work-supporting surface, a needle-feed mechanism including a .needle-oscillating shaft disposed at one side of said work-supporting surface, actuating means for said shaft including a rock-shaft disposed at the opposite side of said work-supporting surface, and means connecting said rock-shaft to said needleoscillating shaft including a rock-lever secured to said needle-oscillating shaft and extending to the rock-shaft side of said work-supporting surface, a crank secured to said rock-shaft, and a link connecting said rock-lever :to said crank.

5. ln a sewing machine having a bed including a worksupporting surface, a standard rising fro-m one end of said bed and a bracket-arm carried by said standard and terminating in a head, a needle-feed mechanism including a needle-oscillating shaft journaled longitudinally of said bracket-arm, a needle-bar carrier fixed to said shaft within said head, a feed-advance shaft journaled. longitudinally of said bed beneath said work-supporting surface, means for imparting ocsillation to said feed-advance shaft, a lower feed mechanism carried by said bed, operative connections between said feed-advance shaft and said lower feed mechanism, a crank carried by said feed-advance shaft, and a rock-lever disposed within said standard, said rock-lever being secured to said first mentioned shaft and being operatively connected .to said crank at a point below said work-supporting surface.

6. Needle-feed mechanism in accordance with claim 5 in which said rock-lever is operatively connected to said crank by means of a connecting link pivote-d to said rocklever at one end and 4to said crank at the other end.

7. In a sewing machine having a bed including a worksupporting surface, a standard rising from one end of said bed and a bracket-arm carried by said standard and terminating in a head, a needle-feed mechanism including a needle-oscillating shaft journaled longitudinally of said bracket-arm, a needle-bar carrier fixed to and carried by said shaft within said head, a needle-carrying needle-bar journaled for longitudinal sliding movement in said needle-bar carrier, a loop-taker shaft journaled beneath said bed, a feed-advance shaft journaled beneath said bed, operative connections between said loop-taker shaft and said feed-advance shaft for imparting oscillation to said feed-advance shaft upon actuation of said loop-taker shaft, a lower feed mechanism disposed beneath said bed, operative connections between said feed-advance shaft and said lower feed mechanism for imparting feed-advance movements to said feed mechanism upon oscillation of said feed-advance shaft, a crank carried by said feedadvance shaft, a rock-lever disposed within said bracketanreisen arm, said rock-lever being fixed to said needle-oscillating shaft, and a link connecting said crank to said rock-lever ata point beneath rsaid work-supporting surface.

` 8. In a sewing machine having a work-supporting surface, a needle-feed mechanism including a needle-oscillating shaft disposed above said work-supporting surface, a lower feed mechanism `disposed below said work-supporting surface, means for imparting feed-advance movements tol said lower feed mechanism including an oscillating feed-advance shaft and a feed-advance rocker secured to said feed-advance shaft, and means for imparting feedadvance movements to said needle-feed mechanism cornprising va crank carried by said feed-advance shaft, and means for lconnecting said crank to said needle-oscillating shaft including a rock-lever operatively connected to said crank andsecured to said needle-oscillating shaft, the ratio of therlength of the rocker to the length of the crank being substantially equal to the ratio of the distance between the axis v of the needle-oscillating shaft and the work-support to the length of the rock-lever. l

9. En a Sewing machine having a rotary driving shaft, a compound feeding mechanism comprising a needlefeed mechanism and a lower four-motion feed mechanism, said needle-feed mechanism including a needle-oscillating shaft arranged parallel to said driving shaft and said lower feed mechanism including an oscillating feedadvance shaft arranged parallel to said driving shaft and a feed-advance rocker secured to said feed-advance shaft, an adjustable eccentric secured to said driving shaft, operative connections between said eccentric and said feedadvance shaft for imparting oscillation to said feed-advance shaft upon rotation of said driving shaft, and operative connections between said feed-advance shaft and said needle-oscillating shaft for imparting oscillation to the latter upon oscillation of the former, said last-mentioned operative connections comprising a crank secured to said feed-advance shaft, a rock-lever secured to said needle-oscillating shaft and operatively connected to said crank, the ratio of the length of the rocker :to the length of the crank being substantially equal to the ratio of the distance between the axis of the needle-oscillating shaft and the point of the needle-feed mechanism in the line of feed to the length of said rock-lever.

l0. In a sewing machine having a rotary driving shaft, a compound feed mechanism comprising a needle-feed mechanism and a lower-feed mechanism, said needle-feed mechanism including a needle-oscillating shaft arranged parallel to said driving shaft, said lower feed mechanism including an oscillating feed-advance shaft arranged parallel to said driving shaft, and adjustable eccentric secured to said driving shaft, a bell-crank lever secured to said feed-advance shaft, a, pitman having a strap portion embracing said eccentric and being pivotally connected to a first arm of said bell-crank lever for imparting oscillation to said feed-advance shaft upon rotation of said driving shaft, a rock-lever secured at one end to said needleoscillating shaft, and means operatively connecting the other end of said rock-lever to a second arm of said bellcrank' for imparting oscilla-tion to said needleoscillating shaft upon oscillation of said feed-advance shaft.

ll. In a sewing machine having arotary `drivin-g shaft, a compound feedrmechanism-comprising*a needle-feed mechanism and a lower-feed mechanism, said needle-feed mechanism including a needle-oscillating shaft arranged parallel to said driving shaft, said lower feed mechanism including an oscillating feed-advance shaft arranged parallel to said driving shaft, and an upstanding feed-advance rocker carried by said feed-advance shaft, an adjustable eccentric secured to said driving shaft, a bell-crank lever secured to said feed-advance shaft, a pitman having a rap portion embracing said -eccentric andlbeing pivotally connected to a first arm of said bell-crank lever for imparting oscillation to said feed-advance shaft upon rotation of said driving shaft, a rock-lever secured at oneend to said needle-oscillating shaft, and means operatively connecting the other end of said rock-lever to a second arm of said bell-crank for imparting oscillationto said needle-oscillating shaft upon oscillation of said feedadvance shaft, the ratio of lthe length of the rocker to the length of the second arm of said bell-crank lever being substantially equal to the ratio of the distance between the axis of the needle-oscillating shaft and the point of the needle-feed mechanism in the line of feed to the length of said rock-lever. r

l2. In a sewing machine having a frame including a bed, a standard rising from one end of said bed and a bracket-arm carried by said standard and o-verhanging said bed, a main-shaft journaled in said bracket-arm, needle-feed mechanism including a needle-oscillating shaft journaled in said bracket-,arm and arranged parallel to said main-shaft, lower four-motion feed mechanism including a feed-advance shaft journaled in said bed and arranged parallel to said main-shaft, an adjustable eccentric carried by said main-shaft in the area above said standard, a bell-crank. secured to Said feed-advance shaft in the arca below said standard, a pitman arranged in said standard and having a strap-portion at one end embracing said eccentric and being pivotally connected at the other end rto one arm of said bell-crank lever for imparting oscillation to said feed-advance shaft upon rotation of said main-shaft, a' rock-lever disposed in said standard and secured at one end to said needle-oscillating shaft, and a link pivotally connecting the other end of said rock-lever to the other arm of said bell-crank lever for imparting oscillation to said needle-oscillating shaft upon oscillation of said feed-advance shaft, said rock-lever extending from said link to said needle-oscillating shaft a distance at least substantially as great as the distance between said needleoscillating shaft and said bed.

References Cited in the tile of this patent UNITED STATES PATENTS 929,761 Gray Aug. 3, 1909 1,450,456 Seymour Apr. 3, 1923 1,685,436 Ringe A Sept. 25, 1928 2,329,484 Quist Sept. 14, 1943

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