US2254779A - Pull-feed mechanism for sewing machines - Google Patents

Description

Sept. 2, 1941. W, MYERS 2,254,779

PULL-FEED MECHANISM FOR SEWING MACHINES Filed 00T.. 24, 1939 4 Sheets-Sheet l gmc/Wto@ I/der Myers Sept. 2, 1941. w. MYERS PULL-FEED MECHANISM FOR SEWING MACHINES Filed OCT.. 24, 1939 A4 Sheets-Sheet 2 El wub/wm walter L/@ens SMM/MM W. MYERS Sept. 2, 1941.-

PULL-FEED MECHANISM FOR SEWING'MACHINES Filed 001'.. 24, 1939 Sept. 2, 1941- w. MYERS l 2,254,779

PULL-FEED MECHANISM FOR SEWING MACHINES `Filed OCT.. 24, 1959 4 Sheets-Sheet 4 Patented Sept. 2, 1941 PULL-FEED MECHANISMFORY SEWING MACHINES Walter Myers, Bridgeport, Conn., assigner to The Singer Manufacturing Company, fElizabeth, N. J., a corporation of New Jersey Application October 24, 1939, SeralNo. 300,914

6 Claims.

'Ihis invention relates to pull-feed mechanisms for sewing machines acting upon the work rearwardly of the sewing machine needle and therefore functioning to pull the work past or away from the stitch-forming mechanism of the machine.

The primary object of the invention is to provide an intermittently feeding pull-feed mechanism for sewing machines adapted for high speed operation whilemaintaining constant a selected amplitude of feed.

Another object of the invention is to provide an eectively operating pull-feed mechanism having means for conveniently changing from one to another predetermined amplitude of feed. The invention has also for its object to provide an improved pull-feed mechanism assembly adapted to be attached as a unit to a sewing machine.

With these and other objects in view, as will hereinafter appear, the invention consists in the devices, combinations and arrangements of parts described in connection with the accompanying drawings which illustrate a, preferred embodiment of the invention and in which:

Fig. 1 is a rear side elevation of a sewing machine containing the improved pull-feed mechanism, the bed-plate extension, or pull-feed bracket, of the machine being shown partly in vertical section. Fig. 2 is a front end elevation of the sewing machine, with the bracket-arm face-plate removed and the bed-plate in vertical section. Fig. 3 is a bottom plan view of the machine. Fig. 4 represents an enlarged vertical section of the pull-feed driving mechanism on substantially the line 4-4 of Fig. 3, the driver pin-wheel being partly broken away. Fig. 5 represents a generally vertical section of the speedchanging mechanism, the section being taken substantially on the broken line 5-5 of Fig. 4, but in a different relative-position of the gears of said mechanism.

The sewing machine shown in the drawings has a bed-plate I, from one end portion of which rises the standard 2 of a tubular bracket-arm 3 overhanging the bed-plate and terminating at its free end in a head 4.

Rotatably journaled in the bracket-arm 3 is a main actuating shaft 5 connected to reciprocate o a needle-bar 6 in the swinging frame l, said frame I being vpivotally hung at its upper end upon a fulcrum-stud 8 secured in the bracketarm head 4, whereby the frame 'I may be vibrated to' impart work-feeding movements to a needle or needles 9 secured to the lower end of the needle-bar 6. In the present machine, the needle-bar frame 1 is vibrated by mechanism corresponding to that more fully disclosed in my prior U. S. Patent No. 2,128,031, Aug. 23, 1938, which also discloses the loop-taker mechanism and the mechanism for actuating the feed-dog I0 employed in the present machine. The clothpresser mechanism, including the pull-feed presser-roller II, is substantially the same as that disclosed in the U. S. patent to J, C. Ringe, No. 1,368,293, Feb. 15, 192 Depending from the front and rear side edges of the bed-plate I are the usual reinforcing ribs or anges I2, and detachably secured by screws I3 to the outer side face of the rearward ange I2 are horizontally spaced supporting-ears I4 of a pull-feed bracket I5. The bracket I5 has a flat work-supporting face I5 which is substantially flush with the upper or work-supporting face of the bed-plate I. At its end adjacent the bracket-arm standard 2, the bracket I5 has an upwardly arched portion I6 providing gear clearance, and detachably secured upon the other end of said bracket is a work-plate I1 provided with a pull-feed roller clearance slot I8.

Depending from the bracket I5 are three bearing-lugs I9, 20 and 2I provided with horizontally alined apertures. Rotatably journaled in the bearing-lug I9 is one end of a roller-carrying shaft 22 which extends freely through the aperture in the lug 20 and, adjacent its opposite end, is journaledin a bearing-bushing 23 secured by a. screw 24 in the lug 2I. Removably secured upon the projecting free end of the shaft 22. adjacent the bushing 23, is a lower pull-feed roller 25 which extends upwardly through .the

work-plate slot I8 and is opposed by the usual spring-depressed presser-roller I I.

The roller-carrying shaft 22 is actuated to rotate intermittently by mechanism providing for changing the speed of rotation of said shaft. To this end, .a spur-gear 26 is secured upon the usual loop-taker and feed-actuating shaft 21 rotatably journaled below the bed-plate I, said actuating shaft 2l carrying a belt-pulley 28 connected by a belt 29 to a pulley 30 carried by the main-shaft 5, whereby the shafts 5 and 2l rotate in one-to-one relation.

The spur-gear 26 is in driving engagement with a peripherally toothed pin-wheel 3| having its hub freely rotatable upon a stud-pin 32 disposed substantially parallel to the shafts 5, 22 and 21 and secured by a screw 33 in the bearingv the side thereof opposite lug I9. As the spur-gear 25 is substantially one half the size of the pin-wheel 3|, the speed of the latter is reduced'to substantially one half oi that of the shaft 21. Projecting from the same side face of the pin-wheel 3| so as to be disposed at diametrically opposite sides of the axis of rotationA of said pin-wheel are substantially parallel and shpuldered stud- pins 34 and 35 secured by screws 35 in suitable apertures in the pin- Wheel 3|. Carried by the projecting ends of said stud-pins are - rollers 31 and 33.

The stud-pin rollers are adapted to engage the teeth 39 of a six-tooth star-wheel 4|! freely rotatable upon a stud-pin 4|, disposed in parallelism with the stud-pin 32 and securedV in a suitable aperture in the bearing-lug 23 by a screw 42.

Screw by a collar 43 secured upon the shaft 22 by a set- The spur-gear 41 is in constant driving engage- 4ment with a relatively larger spur-gear 50 disposed upon the reduced hub of a spur-gear spur-gear 54, and the pinion 53 is likewise 1n con- As illustrated in Fig. 4 of the drawings, the starwheel teeth 39 each have inwardly 'converging straight inner or active portions a, b which are equally and oppositely inclined to radial lines passing centrally through the teeth. The straight inner portion a of each tooth 39'is substantially` parallel vto the adjacent straight inner portion b of the succeeding tooth, and the adiacent parallel inner portions a, b of succeeding teeth are so directed that a straight line intersecting the axis of the star-wheel passes medianly between straight inner portions a, b, of teeth at opposite sides of said'axis. i

The straight inner portions a, b of the starwheel teeth 33 merge tangentially with circular outer or dwell-producing portions c, d, terminating in the circular peripheryof the star-wheel.

The spacing apart of the active inner portions a, b, of the teeth 39 corresponds to lthe diameter of the pin- wheel rollers 31, 33, and the diameter of the curved dwell producing portions c, d, is equal to the spacing of said rollers from ,each other.

In Fig. 4 of the drawings, the roller v31 is at the point of initial engagement of the outer end of the dwell-producing portion c of a tooth 39 and the roller 33 is beginning to engage the inner end of the dwell-producing portion d, of the same tooth. Consequently, the rollers will now travel idly about the curved portions c, d, and the starwheel 39 remains stationary during the fractional revolutionof the pin-wheel 3| required to bring the roller 31 into engagement with the straight inner or active portion a. whereupon the starwheel 40 is rotated until the roller 33 begins to engage the rounded dwell-producing portion c stant mesh with a spur-gear 55, the spur-gears 54 and 55being both journaled for free rotation kupony the roller-carrying shaft 22 and being spaced'fromeach other by a washer 53. The vspur-gear 55fis similarly spaced by a washer 51 fr oxn `the-bearing-lug 23.

` The roller-carrying shaft 22 is provided with a longitudinal slot 53, and shiftable endwise in said slot is a gear-locking key 59, having at one end a notch 50 entered by the reduced end of a shoulder-screw 6| threaded into a collar 32. The collar 52 is slidably disposed upon the shaft 22, its movement in one direction being limited by a collar 53 secured to said shaft 22. extends into a recess 54 formed in the bracket il,

` one end of said recess hunting movement of the collar 32 in a direction away from the collar 53.

At its end opposite the collar 52, the key 53 has a laterally'extending nose 59 adapted alternately to enter a notch 55 in the shaft-aperture of the spur-'gear 54 and a notch 55 in the shaft aperture of the spur-gear ,55. A spring 51 anchored to slide with the key 59 yieldingly urges the keynose 59' to engage the spur- gears 54 and 55, the spacing washers 55 and 51 insuring proper engagement of said spurgears by the key-nose 53.

From the foregoing description, it will be understood that the angle of rotation stepwise im-l parted by the pin-wheel 3| to the star-wheel 43 issuccessively reduced-by the train of speed-re-y ducing gearing which transmits the star-wheel shaft 22 by the key 59, said spur-gears 54 and 5l rotating intermittently at diiferent speeds and of the succeeding tooth. It will be noted that."`

the star-wheel 40, when stationary, is positively held against rotation by the rollers 31, 33 for a very appreciable interval and therefore, that the star-wheel cannot overthrow even at high speed rotation of the pin-wheel. To withstand the stress incidental to high speed operation, the star-wheel teeth 39are preferably reinforcedvby a disk 43 which may be integral with a side face of said star-wheel, or may be brazed or otherwise secured to corresponding side faces of the several Disposed upon the hub of the star-wheel 43 at to the pin-wheel 3|, and secured for rotation with said'star-wheel as by pins 44, is a small spur-gear 45 in constant mesh with a relatively larger spur-gear 45. Thespurgear 45 is force fitted or otherwise rigidly secured upon the reduced hub of a smaller spur-gear 41 twogears Vcapable of being selectively keyed to the lshaft22. Furthermore, the effective workadvancing movement ofthe pull-feed mechanism may also be modified by changing the pullieedroller to one' of different diameter. This may be assembled in the bracket I5 and attached for unison rotation therewith. The small spury gear 41 is journaled for free rotation upon the roller-carrying shaft 22 and is restrained against movement in one direction endwise of said shaft may be readilyeffected by reason of the fact that the pull-feedroller 25 is detachably secured upon the free end of the shaft 22.

The driven portion of the pull-feed mechanism to or detached from thesewing machine as a unit, thereby facilitating proper positioning of the pull-feed mechanism shaft bearings and increasing the durability of the mechanism..

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

1. A pull-feed mechanism assembly adapted to be attached as a unit to a sewing machine, comprising, a supporting bracket, a pull-feed rollerl carrying shaft rotatably journaled in said bracket, a plurality of gear-wheels rotatably The collar 32 mounted upon said shaft, means for selectively keying any one of said gear-wheels to said shaft for rotation therewith, speed-reducing mechanism carried by said bracket for rotating said gear-wheels at different speeds, an intermittently rotated star-wheel journaled in said bracket and operatively connected to said speed-reducing mechanism, and a rotary pin-Wheel in constant operative engagement with said star-wheel for imparting intermittent rotation thereto.

2. A pull-feed mechanism assembly adapted to be attached as a unit to a sewing machine, comprising, a supporting bracket, a pull-feed roller carrying shaft rotatably journaled in said bracket, a plurality of gear-wheels rotatably mounted upon said shaft, means for selectively keying any one of said gear-wheels to said shaft for rotation therewith, speed-reducing mechanism carried Iby said bracket for rotating said gear-wheels at different speeds, an intermittently rotated star-wheel operatively connected to said speed-reducing mechanism and having a plurality of teeth provided with circularly rounded dwell-producing outer end portions, and a rotary pin-wheel having pins spaced diametrically of said wheel and projecting from a side face thereof, said pins being adapted alternately to engage successive teeth of said star-wheel for imparting intermittent rotation thereto.

3. A pull-feed mechanism assembly adapted to be attached as a unit to a sewing machine, comprising, a supporting bracket, a pull-feed roller carrying shaft rotatably journaled in said bracket, a plurality of gear wheels rotatably mounted upon said shaft, means for selectively keying any one of said gear-Wheels to said shaft, a stationary stud-pin carried by said bracket and lengthwise disposed substantially parallel to said shaft, speed-reducing gearing for driving said gear-wheels consisting of a set of spur-gears rotatably journaled uponl said stud-pin and a second set of spur-gears in constant mesh therewith, said second set of gears being rotatably journaled upon said shaft, an intermittently rotated star-wheel journaled in said bracket and operatively connected to said speed-reducing gearing, and a pin-wheel rotatably journaled in said bracket and in operative engagement with said star-wheel for imparting intermittent rotation thereto.

4. A pull-feed mechanism assembly adapted to be attached as a unit to a sewing machine, comprising, a supporting bracket, a pull-feed roller carrying shaft rotatably journaled in said bracket, a plurality of gear-wheels rotatably mounted upon said shaft, means for selectively keying any one of said gear-wheels to said shaft, a stationary stud-pin carried by said bracket and lengthwise disposed substantially parallel to said shaft. speed-reducing gearing for driving said gear-wheels consisting of a set of spur-gears rotatably journaled upon said stud-pin and a second set of spur-gears in constant mesh therewith, said second set of gears being rotatably journaled upon said shaft, an intermittently rotated star-wheel rotatably journaled upon said stud-pin and operatively connected to said speedreducing gearing for rotation therewith, said star-wheel having a plurality of teeth provided with inner active portions and circularly rounded dwell-producing outer end portions, and a rotary pin-wheel having pins adapted alternately to engage successive teeth of said star-wheel, said pins being spaced from each other diametrically of said star-wheel a distance substantially equal to the diameter of the circularly rounded ends of the star-wheel teeth.

5. A pull-feed mechanism assembly adapted to be attached as a unit to a sewing machine, comprising, a supporting bracket providing a worksupporting surface and having spaced bearings, a shaft rotatably journaled in said bearings and having a free end portion extending beyond one of said bearings, a pull-feed roller detachably secured upon said free end portion of said shaft, a plurality of gear-wheels rotatably mounted upon said shaft, means for keying selected ones of said gear-wheels to said shaft for rotation therewith, speed-reducing gearing carried by said bracket and in constant driving engagement with' said gear-wheels, a driving member rotatably journaled uponsaid bracket, and a driven member intermittently rotated by said driving member and operatively connected to said speed-reducing gearing for rotation therewith.

6. The combination with a sewing machine having a work-supporting bed-plate, a rotary actuating shaft, and stitch-forming mechanism including a reciprocatory needle, of a pull-feed mechanism comprising a pull-feed roller disposed rearwardly of said needle, a presser-roller opposed to said pull-feed roller, a rotary pulllfeed roller carrying shaft provided longitudinally thereof with a slot, a plurality of gear-wheels rotatably mounted upon said roller-carrying shaft, a key slidably disposed in said slot for keying selected ones of said gears for rotation with said roller-carrying shaft, a stationary stud-pin disposed substantially parallel to said roller-carrying shaft. speed-reducing gearing in constant driving engagement with said gears and consisting of a set of spur-gears rotatably journaled upon said stud-pin and a second set of spur-gears in constant mesh therewith, said second set of spur-gears being rotatably journaled upon said roller-carrying shaft, an intermittently rotated

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