US2931329A - Work feeding mechanisms for sewing machines - Google Patents

Description

April 1960 R. E. JOHNSON WORK FEEDING MECHANISMS FOR SEWING MACHINES Filed April 12, 1957 5 SheetsSheet l Ralph E. Johnson tilltiy 1 13- hTTORNEY April 5, 1960 R. E. JOHNSON WORK FEEDING MECHANISMS FOR SEWING MACHINES 5 Sheets-Sheet 2 Filed April 12, 1957 IN V EN TOR.

Ralph E. Johnson NQTORNEY April 5, 1960 R. E. JOHNSON WORK FEEDING MECHANISMS FOR sswmc MACHINES 5 Sheets-Sheet 3 Filed April 12, 1957 INVENTOR. Ralph E. Johnson TORNEY Aprii 5, 1960 R. E. JOHNSON WORK FEEDING MECHANISMS FOR SEWING MACHINES Filed April 12, 1957 5 Sheets-Sheet 4 INVENTOR Ralph E. Johnson Aprifl 5, 196% R. E. JOHNSON WORK FEEDING MECHANISMS FOR SEWING MACHINES Filed April 12, 1957 5 Sheets-Sheet 5 xlrlluki IN V EN TOR. Ralph E. Johnson United States PatentO WORK FEEDING IHECHANISMS FOR SEWING MACHINES Application April 12, 1957, Serial No. 652,412

11 Claims. (Cl. 112-210) This invention relates to work feeding mechanisms for sewing machines, and more particularly, to a drop feed or four motion type of work feeding mechanism operable to advance the work fabric across the bed of a cylinder bed type of sewing machine.

It is an object of this invention to provide a new and improved four motion drop feed mechanism providing a work feeding motion having a fiat feed advancing motion across the bed of a cylinder bed of a sewing machine.

In order that the fabric can be stitched into tubes of the smallest possible diameter, it is advantageous in sewing machines having a cylinder bed construction to maintain the smallest possible cross section of the bed. From the point of view of the work feeding mechanism, however, an attenuated cylindrical bed of small cross section is conducive to many serious problems to the solution of which the present invention is directed.

The limited space available within a cylinder bed has presented difficulties in obtaining a feed motion of a desired accuracy and precision. The cramped quarters and limited clearances within the cylinder bed have in the past given rise to arrangements in which the feed motions are derived from necessarily small motions of feed actuating mechanisms. In these cases, the effects of normal play in the parts, lost motion, tolerances, etc., are magnified in the feed motion and precision of feed motion suifers.

In some prior art constructions the desirable fiat feed motion has been sacrificed in favor of an arcuate motion in order to surmount the difficulties encountered in properly actuating a feed mechanism within a cylinder bed.

It is an object of this invention to provide a novel work feeding mechanism for a sewing machine in which highly accurate and precise flat feed motion above the throat plate is obtained.

It is another object of this invention to provide a work feeding mechanism of the above character which is supported and actuated in a novel fashion so as to be subject, during operation, to a minimum of objectionable deformation.

With the above and other objects and advantages in view as will hereinafter appear, this invention comprises the devices, combinations and arrangements of parts hereinafter described and illustrated in the accompanying drawings of a preferred embodiment in which:

Fig. 1 represents a side elevational view of a sewing machine with portions of the machine frame broken away and shown in vertical cross section, illustrating the feed mechanism of my invention applied thereto,

Fig. 2 is a vertical cross sectional view of the head end of the sewing machine taken substantially along line 22 of Fig. 1,

Fig. 3 is a vertical cross sectional view of the standard end of the sewing machine taken substantially along line 33 of Fig. 1,

Fig. 4 represents a bottom plan view of the sewing machine of Fig. 1 with the cylinder bed bottom cover removed,

2,931,329 Patented Apr. 5, 1960 ice Fig. 5 is a vertical cross sectional view of the work supporting bed taken substantially along line 5--5 of Fig. 4,

Fig. 6 is a vertical cross sectional view of the machine base taken substantially along line 6-6 of Fig. 4,

Fig. 7 represents a top plan view of the sewing machine base with the feed mechanism shown in dotted lines,

Fig. 8 is a vertical cross sectional view taken substantially along line 88 of Fig. 7,

Fig. 9 represents a bottom plan view of a modified form of sewing machine base, illustrating the feed mechanism of my invention applied thereto, and

Fig. 10 is an enlarged vertical cross sectional view taken substantially along line 10-10 of Fig. 9.

Referring particularly to Figs. 1 to 4, this invention is illustrated as applied to a sewing machine of the type having a frame base 10 formed with free ended tubular work supporting bed 11 of the so-called cylinder bed variety. The bed 11 need not be a true cylinder but only an approximation thereof around which tubular articles may be placed for sewing. At the bottom the bed is closed by a removable bottom cover 12 to prevent interference of Work fabrics with the mechanism within the bed. Any known type of support (not shown) may be interposed between the base 10 and a supporting table top or other surface to support the sewing machine with the work supporting bed in spaced relation above the machine supporting surface. Figs. 2, 4 and 7 best illustrate that the bed 11 is offset toward the front of the machine frame base, that is, the bed is arranged to extend from that side of the base nearest the operator. That portion of the machine frame which is above the frame base 11 may be of the type illustrated and described in my copending patent application Serial No. 471,766, filed November 29, 1954, now Patent No. 2,862,468, dated December 2, 1958, to which reference may be had for a more complete disclosure. For purposes of the present invention it is sufiicient to understand that the upper portion of the machine frame comprises a hollow vertical standard 13 which supports a bracket arm 14 terminating in a downwardly and forwardly inclined head 15. A main shaft 16, journaled for rotation in the bracket arm, drives an endwise reciprocatory needle bar 17 which is inclined downwardly and forwardly in the head 15. A needle 18 clamped on the needle bar reciprocates through a needle aperture 19 in a throat plate 20 secured on the work supporting bed 12 and cooperates in the formation of lock stitches with a rotary loop taker 21 carried in the bed. Reference may be had to my copending US. patent application Serial No. 634,904, filed January 18, 1954, for a complete description of the loop taker. For purposes of the present invention it will be sufiicient to understand that the loop taker 21 is rotatable about a vertical axis disposed in front of or toward the position of the machine operator from the stitching point as defined by the needle aperture in the throat plate. The loop taker is fast on a loop taker shaft 22 journaled vertically on the work supporting bed. A bevel gear 23 fast on the loop taker shaft 22 meshes with a bevel gear 24 on a bed shaft 25 which extends into the machine base 11. Meshing bevel gears 26 and 27 operatively connect the bed shaft with a shaft 28 journaled vertically in the standard and meshing bevel gears 29 and 30 operatively connect the vertical shaft 28 with the main shaft 16 in the bracket arm of the machine frame.

The work feeding mechanism of the present invention, as applied to the above described cylinder bed sewing machine, comprises a T shaped feed bar, indicated gen erally as 35, of which the cross bar portion 36 is disposed within the confines of the frame base 11 and extends substantially transversely thereof. A stem portion '37 at the l' shaped reed "bar extends lengthwise within substantially the entirelength "of the work supporting cylinder bed 12. Preferably, the stem portion 37 of the feed bar extends along the rear wall of the cylinder bed and a diagonal brace 38 which extendsdiag'onally from the stem to one limb of the cross bar portion of the feedbar may be included to stabilize the feed bar. Se "cured to the feed bar at the free extremity of the stem portion 37 at a point rearwardly of'the stitching point, that is on the opposite side of the stitching point from the axis of the loop taker shaft 22, is a feed dog 39 made fast on the feed bar by screws 40. The feed dog is formed with a plurality of transversely serrated cloth gripping surfaces 41 certain of which extend across the stitching point and all operating through slots 42 in the throat plate to grip and advancethe 'WOIk. V

Extending from the stem portion of the feed bar at points thereon spaced apart lengthwise of the work supporting arm are a pair of arms 43, Fig. 8, each extending downwardly and outwardly toward the front 'of the "machine. Pivotally secured to the free extremity'ofeach of the arms 43 is a short link 44 which extends substantially vertically upwardly from the arms 43. The "upper extremity of each link 44 is pivotally secured to the free extremity of one of a pair of rock arms '45 which extend upwardly and outwardly toward the front 'of the machine from a feed lift rock shaft 46 and terminate substantially verticallyabove said feed bar a'rm 43.

The feed lift rock shaft is disposed substantially verti cally beneath the stem portion of the feed bar a'nd is 'journaled in a pintle 47 fast beneath theframe base and a pintle 48 fast in the free extremity ofthework supporting cylinder bed 12. Referring to Figsfila'nd be made as an integral part of the driving gear 30 and 'a feed advance eccentric 'or cam 52. With this construction the feed lift motion will. always occur'in predetermined timed relation with the feed advance motion and the timing of both of thefeed motions with the rotary hook'may be accomplished readily by an angular adjustment of any one of the gears in the train of hook driving gears, as for instance by an angular adjustment,

of the gear 29 relatively to the shaft 28. V

The feed advance cam 52 is embraced by the bifurcated jaws -53 of a feed advance pitman 54 which extends downwardly through the hollow standard and is pivotally connected to the free extremity of a rock arm; 55 fast on a feed advance rock shaft 56 journaled between hearing pintles 57 carried in the frame base 11. The feed advance rock shaft is formed with an upstanding rock arm 58 disposed substantially at a right angle to the rock arm 55. At its upper free extremity, the rock arm 58 is pivotallysecured to the rearward limb of the cross bar portion 36 of the T shaped feed bar 35 W H Regulation of the length of work feeding stroke is attained by means of a slide block 59 pivoted on a 'stud 60 threaded into the feed advance pitrnan in the machine standard. The slide block 59 is embraced in a guide slot 61 formed in a feed regulating and reversing lever 62 fulcrumed on a stud 63 carried in the machine standard. The feed regulating lever includes a threaded handle 64 which extends through a slot 65 formed in the front wall of the standard and through a slot 66 with indicia plate 67 carried by the standard. By means of a knurled adu'stingnut 68, any desired stitch length can be determined or the direction of stitching reversed by shifting enemas is bifurcated, as indicated at.70,' and embraces a stabiliiing guide roller 71 journaled on a shouldered screw 'nism. The limbs of the feed bar may preferably be ribbed, as illustrated particularly in the cross sectional 'views Figs. 5, 6 and 8, to provide for rigid vertical der bed. The leg portion thus provides a steadier supthe handle '64 to change the'angular' relation between the guide slot 61 and the feed advance pitman 54. V

The forward limb of the, cross bar portion of the feed bar beyond its juncture with the diagonal cross brace 38 stability of the feed bar. The T shape of'the feed bar 'alsoprovides for operable connections with the feed actuating mechanism in a manner conducive to movement in a highly desirable path which produces a linear feed straight across the cylinder work supporting bed of the machine and an advantageously flat feed'advancing motion ofthe feed dog. Considering the feed advance actuating connection to the feed bar and referring to Figs. 4 and '6, it will be noted that the construction thereof "provides for an extremely Wide spacing between the point of'conn'ection of thefeed advance rock arm '58 with 'the :feed bar am; th'e'islidable stabilizing conn'ectionbetween the bifurcated portion 70 of the feed bar and the guide roller 71. Also as illustrated'in Figs.

.feed bar, and the stabilizing connection of the feed'bar with the guide roller 71 occurs at the opposite side of the feed lift connections. Since these connections are spaced apart inthe relatively wide frame base 10,. rather than being crowded together inithe cylinder bed as is conventional in this type of machine, any tendency for the feed bar to r ock idly i'n a horizontal plane is minimized. Considering the feed lift motion-and referring particularly to Figs. 7 and 8, the pair of connections between the feed lift rock shaft and the feed bar being spaced lengthwise of the stem portion 37 of the feed barresist any 'tendency for the feed bar to rock idly in 'a verticalplan'e. The short links 44 which depend from the feed lift rock arms 45 to the feed bar arms 43 give rise to a lifting motion of the feed bar at the beginning and end of each feed advance stroke to augment the motion imparted by 'thefe ed lifting mechanism and thereby to provide an extremely-fiat feed advance motion which is considered desirable because the work fabrics will then be gripped evenly and continuously by the feed dog during a greater portion of the feed advance stroke than with heretofore conventional arrangements.

Thefpresent invention provides a compact work feedingfmechani'sm which may not only be confined within the limited space available in a cylinder bed of 'a sewing machine but which is adapted to be arranged at one side of, and in the preferred form to the rear of, the vertical axis rotary loop taker within a cylinder bed. This feature is highly advantageous inasmuch as it makes possible a feed dog arrangement which is cantilevered over the stitching point from only one side leaving the other side open for ready access to the loop taker as, for instance, for removing and, replacing a bobbin therein.

Referring to Figs. '9 and 10, the feed mechanism of this inventionis illustrated as applied to ,a modified form of sewing machine frame which differs from that previously described in that the frame base 10 is formed with an hutwardly projectingale'g portion 80. As indicated in the drawings, the leg portion extends substantially parallcl to the cylinder bedll and rearwardly thereof with respect to the normal position of the machine operator. 7

A space 81 is provided between the leg 80 and the cylinder bed ll forpassage of work fabrics. around'th'e cylinport for the sewing machine to minimize tipping of the machine. In the embodiment illustrated in Figs. 9 and 10, the woi k feeding mechanism remains unchanged except for the feed advance rock shaft 56 which has been extended as at 56' within the leg portion 80 of the frame substantially the entire length thereof. A pintle 82 carried in the extremity of the leg portion is embraced by the extended portion 56 of the feed advance rock shaft. This extended feed advance rock shaft provides not only for more convenient access to the outboard pintle 82 thereof, but being elongate provides for an extremely stable feed advance actuating connection to the feed bar, that is, one in which lost motion, etc. between the pintles 82 and 57 and the feed bar will reflect in a minimum of objectionable rocking movement being transmitted to the feed bar.

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

1. A four motion work feeding mechanism for a sewing machine having a frame base and a free ended Work supporting bed extending from said frame base, comprising a feed bar formed with mutually perpendicular limbs, a first of said limbs extending lengthwise within the work supporting bed, a second of said limbs extending within said frame base, feed lift actuating mechanism including a feed lift rock shaft extending lengthwise within the work supporting bed, a plurality of operative connections between said feed lift rock shaft and said feed bar, said connections arranged at points on the first of said limbs spaced lengthwise of said work supporting bed, and feed advance actuating mechanism including a feed advance rock shaft disposed within said frame base, an operative connection between said feed advance rock shaft and said second limb of said feed bar, and means for actuating said feed advance and said feed lift rock shafts.

2. A four motion work feeding mechanism for a sewing machine having a frame including a base and a free ended work supporting bed extending from said frame base, comprising a feed bar formed with mutually perpendicular limbs, a first of said limbs extending lengthwise within the work supporting bed, a second of said limbs extending within said frame base, feed lift actuating mechanism including a feed lift rock shaft extending lengthwise within the Work supporting bed, means for actuating said feed lift rock shaft, a plurality of operative connections between said feed lift rock shaft and said feed bar, said connections arranged at points on the first of said limbs spaced lengthwise of said work supporting bed, feed advance actuating mechanism including a feed advance rock shaft disposed within said frame base, means for actuating said feed advance rock shaft, an operative connection between said feed advance rock shaft and said second limb of said feed bar, and a slidable stabilizing connection between said feed bar and said sewing machine frame.

3. A work feeding mechanism for a sewing machine having a frame formed with a free ended work supporting bed, comprising a feed bar extending lengthwise within the confines of said work supporting bed, complemental bearing means on said feed bar and on said frame including a cylindrical guide member carried by one of said parts and bifurcated jaws carried by the other of said parts in slidable engagement with said guide member, means for shifting said feed bar in a direction lengthwise of said guide member, said means including an oscillatory member extending lengthwise within the confines of said work supporting bed, means actuated by said sewing machine for oscillating said member, a plurality of operative connections between said oscillatory member and said feed bar, said connections arranged at points on said feed bar spaced lengthwise of said work supporting bed, and mechanism carried in said frame and driven by said sewing machine for vibrating said feed bar in a direction transversely of said guide member.

4. A four motion work feeding mechanism for a sewing machine having a frame formed with a free ended work supporting arm, comprising an elongate feed bar extending within substantially the entire length of said work supporting arm, a feed dog secured to said feed bar at the free extremity of said work supporting arm, first feed actuating mechanism driven by said sewing machine and extending within said work supporting arm for imparting motion in one direction to said feed bar, a plurality of operative connections between said mechanism and said feed bar, said connections spaced lengthwise along said work supporting arm, second feed actuating mechanism driven by said sewing machine for imparting motion to said feed bar in a direction substantially perpendicular to that imparted by said first feed actuating mechanism, an operative connection between said second feed actuating mechanism and said feed bar arranged at one side of said plurality of connections of said feed bar with said first feed actuating mechanism, and a slidable stabilizing connection between said feed bar and said sewing machine frame at the opposite side of said plurality of connections.

5. A four motion work feeding mechanism for a sewing machine having a frame including a machine supporting base and a free ended work supporting bed extending from said base, said work feeding mechanism comprising a feed bar disposed in said machine supporting base and extending lengthwise into said work supporting bed, a feed dog secured to said feed bar within said work supporting bed, a slidable stabilizing connection between said sewing machine and a point on said feed bar within said machine supporting base, first feed actuating mechanism carried by said frame and driven by said sewing machine, a plurality of spaced operative connections of said first feed actuating mechanism with said feed bar Within said free ended work supporting bed for imparting substantially translatory vibration to said feed bar, second feed actuating mechanism carried by said frame and driven by said sewing machine, and operative connections between said second feed actuating mechanism and said feed bar to impart vibratory motion to said feed bar in a direction substantially perpendicular to the motion of said feed bar in response to said first feed actuating means.

6. A four motion work feeding mechanism for a sewing machine having a frame including a frame base and a narrow free ended work supporting bed extending from said frame base and a driving shaft journaled in said frame, comprising a T shaped feed bar, a stem portion of said feed bar extending lengthwise Within the work supporting bed, a cross bar portion of said feed bar extending transversely within said frame base, feed lift actuating mechanism including a feed lift rock shaft actuated from said driving shaft and extending lengthwise within said work supporting bed, feed advance actuating mechanism including a feed advance rock shaft actuated from said driving shaft and disposed within said frame base, an operative connection between said feed advance rock shaft and one extremity of said cross bar portion of the feed bar, the opposite extremity of said cross bar portion being bifurcated, and a cylindrical guide member carried by said frame base and disposed between the bifurcation of said cross bar portion of the feed bar.

7. A four motion Work feeding mechanism for a sewing machine having a frame base and a narrow free ended work supporting bed extending from said frame base comprising, a T shaped feed bar, a stem portion of said feed bar extending lengthwise within the work supporting bed, a cross bar portion of said feed bar extending transversely within said frame base, a guide roller journaled on a substantially vertical axis beneath said frame base, one extremity of the cross bar portion of said feed bar being bifurcated and arranged to embrace said guide roller, a feed advance rock shaft carried in said frame base and actuated by said sewing machine, means operatively connecting said feed advance rock shaft to the opposite extremity of the cross bar portion of said T shaped feed bar to impart vibratory motion to said feed bar perpendicular to the axis of said guide roller, a feed lift rock shaft actuated by said sewing machine and extending "lengthwise within the ivorkisup'porting bed, -a plurality of operative connections between said feed lift ;ing machine having a frame formed with a free ended work supporting bed comprising a feed bar extending lengthwise Within the confines of said work supporting bed, means for advancing and returning said feed bar transversely across said work'supporting bed, andmeans for lifting and lowering said feed bar vertically in said work supporting bed, said last 'named'means including aroc'k shaft extending lengthwise within'the confines of said work supporting-bed, means actuated by said sewing machine for oscillating said rock .shaft, a pair of rock arms extending from said rock shaft in spaced relation thereon lengthwise of said work supporting bed, 'a pair of links-pivotally secured one to the extremity ofeach of said rock arms, a pair -'of feed bar arms extending from said feed bar in spacedrelation thereon le'ngthwise of fSZiid WOIk supporting bed, and means pivotally securing each of said pair of links to a respective one 'of said feed bar arms substantially vertically beneath the pivotal connection of the link with said crock arm.

9. A founmotion work feeding mechanism-for a sewing'machine having a frame base and a narrow free ended work supporting bed extending from saidframe'base,

comprising a T shaped feed bar, a stem portion of'said' ifeedb'ar extending lengthwisewithin the work supporting "bed, a cross bar portion of said'feed bar extending'tra'nsversely withinsaid frarne'base, feed lift actuating mechanism including a feed lift rock shaft actuated by said sewing machine and extending lengthwise within said work supporting bed substantia ly vertically beneath'said feed her stem portion, a pair of upwardly and outwardly extending rock'arms extending from-said feed lift rock shaft in spaced relation thereon lengthwise'offsaid work supporting bed, a pair of feed bar arms extending from connected between each of said vertically aligned feed rlift rock arms and feed bar arms, feed advance actuating ,mechanism including a feed advance rock'shaft actuated by said sewing machine and disposed within said frame base, an operative connection between said feed advance irock shaft and one extremity of said cross bar portion ofthe feed bar, and a slidable stabilizing connection between the opposite extremity of said cross barportion and said frame base.

10. In a' sewing machine-having a frameincludin'g a supporting base defining a plane of support for the sewing machine, a free ended work supporting arm extending from the supporting base above said plane of support a 'nd adapted to accommodate tubular articles lengthwise there- 'on,and a bracket arm extending over said work supporting arm, stitch forminginstrumentalities including a needle carried in said bracket arm for e'ndwise reciprocating movement in a path intersecting said work supporting arm at a stitching point thereon, a loop taker supported :for circular movement within the confines of said work supporting arm about a substantially vertical axis disposed in'frontof the stitching point, a feed bar extending lengthwise within the confines of said work supporting arm and having a portion extending behindsaid stitch- ;ing point, mechanisrnvcarried within said frame and operatively connected to said feed bar for imparting move ment to said feed bar transversely of the longitudinal axis of said Work supporting arm, 'a'feed dog extending'trans- ,versely of the longitudinal axis of said work supporting arm beneath s aid stitching point and being attached to said portion of said feed bar behind said stitching point.

'11. A fo ur motion 'work feeding mechanism for a sewing machine having a frame including a supporting base defining a plane of support for the sewing machine, and a free ended work supporting bed extending from the supporting base above said plane of support, means defining a'substantiallyplanar work supporting area about a stitching point on said work supporting bed, said work feeding mechanism comprising, affeed' bar extending within said work'supp'orting bed, a feed dogsecur'ed to. s aid feed bar within said work snppo'r'tingfbed, a guide'roller journaled in said sewing machine frame on an axis substantially perpendicular to the plane ofjsaid. work supporting area about said stitching point, said feed bar being provided Twith bifurcated jaws embracing said guide roller, a feed lift rock shaft carried by said frame and actuated by said sewing machine, a plurality of-spaced operativew connections of said feed lift rock. shaft with said feed bar for imrpar'ting substantially translatory vibration to said feed bar in a directionaxially of said guide roller, a feed advance rock shaft carried by said frame and actuated by said sewing machine, and means operatively connecting said feed advance rock shaft to'said feed bar to impart vibratory motion to said feed'bar perpendicular to the axis of said guide roller.

References Cited in thefile of this patent UNITED STATES PATENTS 402,259 Leilich n Apr. 30, 1898 2,386,660 Clayton Oct. 9, 1945 2,453,072 Johnson Nov. 2, 1948 2,808,793 Ayres c Oct. 8,1957

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