US1729994A - Feeding mechanism for sewing machines - Google Patents

Description

Oct. l, 1929. F. M. CARD FEEDING MECHANISM FOR SEWING MACHINES Filed Aug. l, 1928 2 Sheets-Sheet Frederic Oct. l, 1929. F. M. CARD 1,729,994

FEEDING MECHANISM FOR SEWING MACHINES Filed Aug. 1, 1928 2 Sheets-Sheet 2 gn/manto@ Frederic Jil- 67W 1,44 liv Patented Oct. l, 1929 PATENT OFFICE FREDERIC IVI. CARD, OF BRIDGEPORT, CONNECTICUT, ASSIGNOR TO THE SINGER MANU- FACTURING COMPANY, OF ELIZABETH,

JERSEY NEW JERSEY, A CORPORATION 0F NEW FEEDING MECHANISM FOR SEWING MACHINES Application filed August 1,

This invention relates to improvements in feeding mechanisms for sewing machines and has for its object to provide means for more etliciently advancing the work past the stitchtorming mechanism of sewing machines of more particularly the work-supporting post and cylinder work-arm types.

In sewing machines of the vertical worksupporting post type it has been a common practice to employ a four-motion feeding mechanism in which the feed-dog has a decidedly elliptical path of movement, rendering it dil'licult to prevent a back-drag upon the work during the return movement of the feed-dog.

In the present improvement, the feed-dog is maintained substantially parallel to the plane of the work throughout its complete feeding movement, instead of being tilted at constantly varying angles as in the elliptical movement type of feed-dogs. Vhile prior feeding mechanisms have heretofore been devised to obtain a rectangular path of movement for the feed-dogs, such mechae nisms are unadapted for embodiment in the constricted space available in post machines or are not designed to meet present high speed requirements.

In a preferred embodiment of this invention, a work-supporting post type of sewing machine is provided with a feeding mechanism in which the feed-dog is supported by a carrier of which one end is pivotally connected to the upper arm of a rocking feed-lever, disposed lengthwise of the post and having for its primary function to impart work-advancing and return movements to the feed-dog. This lever is fulcrumed intermediate its ends upon aslidc-block vertically reeijnocatt-d in guideways within the work-supportinf post. whereby said lever has for an additional function the raising and lowering of one end of the feed-dog. The other end of the feed-dog carrier is slidingly supported upon the upper end of a feed-lift bar vertically reciproeated in bearings provided within the work-supporting post. By properly timing the rising and falling movements of the feed-lift bar and the feed-lever supporting slide-block with 1928. Serial No. 296,678.

respect to the rocking movements of said feed-lever, substantially rectangular movements may be imparted to the feed-dog.

The forked lower end of the feed-lever is engaged by a crank on the forward end of a rock-shaft journaled beneath the bed-plate of the machine and having the usual pitman connections with an adjustable eccentric upon the main-shaft journaled in the bracketarm of the machine. The slide-block is provided with a depending arm having linkconnections with a crank-arm upon a rockshaft actuated by pitman and eccentric connections with a loop-taker actuating shaft journaled beneath the cloth-plate. The feedlift bar is secured for vertical adjustment upon a fork engaged by another eccentric upon said loop-taker actuating shaft, which shaft is driven in one-to-one relation with respect to the rotations of the main-shaft by suitable belt-connections therewith.

In the accompanying drawings, Fig. l is a longitudinal section of a sewing machine in which the present improved feeding meehanism has been embodied. Fig. 2 is a bottom plan view of the sewing machine. Fig. 3 is a vertical section of the work-supporting post, omitting the loop-taker. Fig. 4. is a perspective view of the feeding mechanism. Fig. 5 is a detail view in elevation of the adjustable connection between the feedlift bar and the fork at its lower end.

Referring to the drawings, the feeding mechanism is illustrated as embodied in a sewing machine having a bed-plate 1 from one end of which rises a hollow post 2 upon which is secured the usual standard 3 of an overhanging bracket-arm 4 terminating in a head 5. The mechanism contained within the bracket-arm is that of a well known type of zigzag stitch sewing machine illustrated, for instance, in the U. S. patent to C. F. Gray, No. 933,032, August 3l, 1909. In general, this mechanism comprises a rotary main or actuating shaft 6 carrying at one end a driving pulley 7 and at its opposite end a crank-plate 8 provided with a crankpin 9 connected by means of a link l() with a needle-bar 1l carrying at its lower end a needle 12.

The needle-bar 11 is journaled for endwise reciprocation in suitable bearings provided in a vibratory frame 13 pivoted at its upper end within the head 5 upon a fulcrum-stud 14. Suitably connected with the frame 13 is one end of a link-bar 15 of which the opposite end is formed as a forli` 16 between the spaced member of which is disposed a triangular cam 17 carried by a transverse camshaft 18. Fixed upon the cam-shaft 18 is a gear-wl'recl 19 driven by a smaller gear 20 upon the main-shaft 6 at one-half the speed of rotation of the main-shaft. The link-bar 15 receives vibratory movements upon its pivotal connection with the frame 13 from the actuating cam 17, but is free to move endwise in relation to said cam. In order that the sidewise actuation imparted to the linlfbar by the cam 17 may be partially converted into endwise movement to thereby vil ate the needle laterally, said link-bar is connected by means of the link 2l with an adjustable fulcrum-stud 22, as more fully described in said prior Patent No. 933,032.

Rising from the bed-plate 1 at the forward end thereof is a work-supporting post 23, which is substantially rectangular in transverse section and supports av throat-plate 24 upon its upper end. Housed within said post 23 directly below the throat-plate 24 is a loop-taker 25 of the rotary-hook type, carrying a mass of under thread around which the needle-thread loops are cast in the formation of lock-stitches. The axis of rotation of the loop-taker is horizontal and transverse to the plane of lateral vibration of the nee` dle. The loop-taker 25 is carried by a short shaft 26 ournaled in the bearing-bushing 27 located in a suitable aperture provided in the post 23,` said shaft 26 carrying a bevel-gear 28 in mesh with a similar gear 29 upon the upper end of a vertically disposed, intermediate shaft 30. rlhe vertical shaft 30 is journaled in bearing- lnishings 31 and 32 lived in apertured lugs 33 and 34 disposed within the post 23. At its lower end, the shaft 30 carries a bevel-gear 35 driven by a gear 36 fixed upon the forward end of a loop-taker actuating shaft 37 journaled in suitable bearings provided at the under side of the bed-plate 1. The ratio of gears 35 and 36 is such that the vertical shaft 30 rotates twice for each rotation of the shaft 37. Sccured upon the shaft 37 is a pulley 38 engaged by a belt 39 passing over a pulley 40 upon the main-shaft 6, the shaft 37 rotatingl once for cach rotation of the main-shaft 6.

Opposed to the usual presser-foot 41, in advancing the work past the stich-forming` mechanism, is a feed-dog 42 operatingr through slots as 43 provided in the throat` plate 24. The feed-dog 42 has a laterally extending shank 44 secured by screws 45 upon a vertically disposed plate or feed-dog carrier 46 free to swing upon a pivot-bolt 47 in the upper end of a feed-lever 48. The feed-lever 48 is provided with a vertically disposed guide-slot 49 receiving the carrierplate 46 and serving to brace the latter, said feed-lever being not only actuated to impart work-advancing -and return movements to the feed-dog, but also to raise and lower one end of said feed-dog. Accoroingly the feedlcver 48 is formed intermediate its ends with an apertured boss 50, in which is secured a fulcruin-pin 51 journaled in alined apertures in spaced lugs as 52, projecting from one side of a slide-block 53. The slide-bloeit 53 is confined to vertical reciprocation in an undercut guideway 54 provided within the post 23, in one of the walls thereof. Dcpending i'rom said slide-block is an arm 55, connected by means of a link 56 with a cranl-iarm 57 having a split hub clamped by means of a screw 58 upon one end of a short feedlift rock-shaft 59. rlhc rock-shaft 59 is ourualed in apertured bearing lugs, as 60, at the under de of the bed-plate 1 and has another ritt-aria 61 suitably connected to one end a pitnian 62 ot' which the opposite end is 'forzpei'l as a strap 63 embracing an eccentric tupon the actuating shaft 37.

'ihc feed-lever 48 is forked at its lower end to slidingly receive a pivot-block 65 upon a crai'il-piu 66 of an arm 67 extending laterally from a feed-shaft 68. T he feed-shaft 68 is journaled in apcrtured bearing lugs, as 69, at tlie under side of the bed-plate 1 and carries a crank-arm 70 suitably connected to a vertically directed pitman 71 having at its upper end a split sig-ap 72 embracing an adjustable eccentric 73 upon the main-shaft 6. The adjustable eccentric 73 is constructed substantially in accordance with the disclosure in the U. S. patent to Dial et al., No. 718,988, January 27, 1903, and it is therefore deemed unneccesary to herein describe the saine in detail.

The feed-dog carrier 46 is forked to provide a slot 74 at its end opposite to the pivot-bolt 47, said slot 74 slidingly receiving a guideblock 75 pivotally supported between the spaced members of a fork 76 at the upper end of a feed-lift bar 77. rllhis bar 77 is journaled for vertical reciprocation in a bearinglug 78 within the post 23 and in an aperture in the lug 34, the flattened lower portion 79 oi' said bar being slidingly fitted to a grooved guideway 8() formed in the rear face of a fork 81 stradding an eccentric 82 upon the actuating shaft The flattened portion 79 0l of the feed-lift bar is provided with a vertically elongated slot 83 through which passes a securing screw 84 threaded into the fork 81.. whereby the bar 77 may be vertically adjusted with respect to said fork. In order to more accurately efect this adjustment, an adjusting screw 85 is threaded into the lower end of the bar 77, said screw 85 having a grooved head 86 engaged by spaced projections on a meager i detaining-plate 87 secured upon the under side of the fork 8l, whereby the plate 87 holds the screw 85 against endwise movement to effect vertical adjustment of the bar 77 upon manipulation of the screw.

It will be understood that by vertically ad justing the bar 77, one end of the feed-dog 42 may be projected the desired distance above the throat-plate in accordance with the character of the work to be stitched. The other end of the feed-dog may likewise be adjustably raised or lowered by loosening the clamp-screw 58 of the crank-arm 57, this adjustment being permitted by reason of the forked lower end of the feed-lever 48.

The operation of the present improved feeding mechanism will be readily apparent from the foregoing description. The rocking feed-lever 48 imparts Work-advancing and return movements to the feed-dog of an extent which may be predetermined by adj ustment of the feed-eccentric upon the mainshaft 6. The feed-dog may be maintained horizontal throughout its entire movement by simultaneously raising and lowering opposite ends thereof as described, consequently obviatingr all back-drag upon the work by the feed-dog during its return movements, regardless of the stitch-length selected.

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

1. Feeding mechanism for sewing machines, comprising a feed-dog carrier, a feedlever, a pivotal connection between said carrier and the feed-lever, a feed-lift bar, an operative connection between said feed-lift bar and the carrier spaced in the direction of feed from the pivotal connection of the feedlever therewith, means for vertically reciprocating the feed-lift bar, means for vertically reciprocating the feed-lever, and means for rocking said feed-lever to impart work-advancing and return movements to the feeddog carrier.

2. Feeding mechanism for sewing machines, comprising a feed-dog carrier, a feedlever, a pivotal connection between said carrier and the feed-lever, a vertically reciprocatory slide, a pivotal support for the feedlever upon said slide, a feed-lift bar, an operative connection between said feed-lift bar and the carrier spaced in the direction of feed from the pivotal connection of the feedlever therewith, means for vertically reciprocating the feed-lift bar, means for vertically reciprocating said slide, and means for rocking said feed-lever upon said slide to impart work-advancing and return movements to the feed-dog carrier.

3. Feeding mechanism for sewing machine-s, comprising a feed-dog carrier, a feedleve-r., a pivotal connection between said carrier and the feed-lever, a feed-lift bar, an operative connection between said feed-lift bar and the carrier spaced in the direction of feed 'from the pivotal connection of the feedlever therewith, means for vertically reciprocating the feed-lift bar including an adj ustable connection for determining the extent of rising movement of said feed-lift bar, means for verticallyI reciprocatingl the feed-lever, and means for rocking said feed-lever to im.- part work-advancing and return movements to the feed-dog carrier.

4. Feeding mechanism for sewing ma.- chines, comprising afeed-dog carrier, a feedlever, a pivotal connection between said carrier and the feed-lever, a vertically reciprocatory slide, a pivotal support for the feed-lever upon said slide, means for rocking said feedlever upon said slide to impart work-advancing .and return movements to the feed-dog carrier, means for vertically reciprocating said slide to impart rising and falling movements to one end of said carrier, and additional feed-lift means for imparting rising and falling movements to the other end of said carrier.

5. Feeding mechanism for sewing machines, com p-rising a feed-dog carrier, a feedlever, a pivotal connection between said carrier and the feed-lever, a vertically reciprocatory slide, a pivotal support for the feed-lever upon said slide, means for rocking said feedlever upon said slide to impart work-advancing and ret-urn movements to the feed-dog carrier, means for vertically reciprocating said slide to impart rising and falling movements to one end of said carrier, additional feed-lift means for imparting rising and falling movements to the other end of said carrier, and means for adjustably determining the extent of rising movement of one end of said carrier with respect to the rising movement of the other end thereof.

6. In a sewing machine, the combination with stitch-forming mechanism comprising a reciprocatory needle, a loop-taker complemental to said needle in the formation of lock-stitches, an actuating shaft and connections therewith for reciprocating said needle, and a loop-taker actuating shaft, of feeding mechanism including a feed-dog carrier, a feed-lever pivotally connected with said carrier, operative connections between said mainshaft and the feed-lever for rocking said lever to impart work-advancing and return movements to the feed-dog carrier, operative connect-ions between said feed-lever and the looptaker actuating shaft for raising and lowering said feed-dog carrie-r, a feed-lift bar independent of said feed-lever, means for vertically reciprocating said feed-lift bar from the loop-taker actuating shaft, and an operative connection between said feed-lift bar and the feed-dog carrier.

7. In a sewing machine having a bed-plate, a vertically disposed work-supporting post rising from said bed-plate, and an overhanging bracket-arm, a needle, a loop-taker housed within said post, and work-feeding mechanism including a feed-dog carrier, a vertically reciprocatory slide housed within said post, a feed-lever fulcrumed upon said slide, av guideway or said slide upon one of the walls of said post, a pivotal connection between said feed-lever and the feed-dog carrier, a feed-lift bar housed Within said post, an operative connection between the feed-lift bar and the feed-dog carrier, means for Vertically reciprocating said slide, means for vertically reciprocating said feed-lift bar, and nli'ens for rocking the feed-lever upon said s 1 e.

In testimony whereof, I have signed my name to this specification.

FREDERIC M. CARD.

Images