US2029278A

US2029278A - Adjustable eccentric for sewing machines

Info

Publication number: US2029278A
Application number: US735612A
Authority: US
Inventors: Jake H Stearns
Original assignee: Singer Co
Current assignee: Singer Co
Priority date: 1934-07-17
Filing date: 1934-07-17
Publication date: 1936-01-28
Anticipated expiration: 1953-01-28
Also published as: DE629392C; GB435303A

Description

Jan. 28, 1936. J. H. STEARNS 2,029,278

' ADJUSTABLE ECCENTRIC FOR SEWI-NGMACHINES Filed July 17, 19:54 3 Sheets-Sheet 1 mac/who'd Jan/be fl dearnd I Jan. 28, 1936.

J. H. STEARNS ADJUSTABLE ECCENTRIC FOR; SEWING MACHINES Filed luly 17, 1934 s Sheets-Sheet 2 H mm W m m w d A n 7 51 Jan. 28, 1936. J. H. STEARNS I ADJUSTABLE ECCENTRIC FOR SEWING MACHINES Filed July 17, 1934 s Sheets-Sheet 5 Jake H s teamnd Guam;

Patented. Jan. 28, 1936 UNITED STATES PATENT OFFICE ADJUSTABLE EooEN'rmc roa SEWING MACHINES Application July 17, 1934, Serial No. 735,612

8 Claims.

This invention relates to improvements in ad- .iustable eccentrics for use in connection with sewing machines and is herein described as a sewing machine feed-actuating eccentric, al-

5 though adapted to other uses in connection with sewing machines.

The primary object of the invention is to provide an actuating eccentric forsewing machines which is conveniently adjustable as to eccentricity 1 and definitely maintains any one of a plurality of set positions of eccentricity at high speeds of operation and under heavy load conditions.

More specifically, the present invention aims to improve the type of adjustable feed-eccentric dis- 15 closed in the U. S. Patent to C. H. Willcox et al.,

No. 572,041, November 24, 1896.

With the above and other more specific objects in view, the invention comprises the devices, combinations and arrangements of parts hereinafter described in connection with the accompanying drawings, from which the several features of the invention and the advantages attained thereby will be readily understood by those skilled in the art.

In the accompanying drawings, Fig. 1 represents a vertical section longitudinally of the sewing machine. Fig. 2 represents a transverse section of the machine through the arm-standard thereof and substantially on the line 2-2 of Fig. 30 1. Fig. 3 is an enlarged detail view of one form of the improved feed-adjusting device from the same side as shown in Fig. 2, but with the parts relatively adjusted into a different position thereof. Fig. 4 represents a sectional view of the 35 feed-adjusting device substantially on the line 4-4 of Fig. 3. Fig. 5 is a face view of the feedeccentric flange from the side thereof opposite to the eccentric. Fig. 6 is a similar view of the feed-adjusting disk from the eccentric-flange side 40 thereof. Fig. 7 represents a detail sectional view ofthe feed-adjusting device substantially on the line 'l-Lof Fig. 3. Fig. 8 represents a longitudinal section of a modiflcation of the feed-adjusting device. Fig. 9 represents a cross-section 45 of the modification substantially on the line 9-9 of Fig. 8. Figs. 10 to 13, inclusive, represent perspective views of the component parts of the modified feed-adjusting device illustrated in Fig. 8.

Referring to the drawings, the present improvements have been embodied in a sewing machine including a frame comprising a bed-plate I, from one end ofwhich rises a hollow standard 2 of a tubular bracket-arm 3 overhanging the bed-plate 56 and terminating at its free end in a head 4.

Disposed within and extending longitudinally of the bracket-arm 3 is a rotary main or needlereciprocating shaft 5, carrying at its outer end a combination balance-wheel and driving-pulley 6. Adjacent to the balance-wheel, the shaft 5 is 5 journaled in a ball-bearing I, the opposite end of the shaft being journaled in a bearing bushing 8 within the bracket-arm 3. The shaft 5 carries a crank-disk 9 connected by a link III to the upper end of .a needle-bar ll, journaled for ver- 10 tical reciprocation in an elongated bushing l2 suitably fixed in the bracket-arm head 4. At its lower end, the needle-bar II carries a needle l3. Also journaled for vertical movement in the bracket-arm head is the usual presser-bar [4, to the lower end of which is secured a presser-foot l5.

Suitably secured upon the main shaft 5 for rotation therewith is a peripherally grooved pulley it connected, by a clip-belt H, with a pulley l8 of one half the size of pulley It. The pulley I8 is carried by one end of a loop-taker shaft 19 disposed below the bed-plate l and in parallelism with the main shaft 5. Adjacent to the pulley l8, the loop-taker shaft I9 is journaled in a ballbearing 20, the opposite end of said shaft being journaled in a bearing bushing 2| and-carrying a loop-taker 22 adapted to cooperate with the needle IS in the formation of lock-stitches.

The work to be stitched is intermittently advanced by a feeding mechanism of the lower fourmotion type and comprising a feed-dog 23 carried by a feed-bar 24. One end of the feed-bar is operatively connected to a crank-arm upon one end of a feed-lift rock-shaft 25 journaled below and extending longitudinally of the bed-plate I. Adjacent to its opposite end, the rock-shaft 25 carries a crank-arm 26 pivotally connected to the lower end of a pitman 21 of which the opposite end has a strap 28 embracing a suitable feed-lift eccentric 29 carried by the main shaft 5.

The feed-bar 24 is also pivotally connected to a feed-rocker 30 carried by a feed-advance rockshaft 3| journaled below and extending longitudinally of the bed-plate l. Clamped upon the rock-shaft 3| is a crank-arm 32 pivotally connected to the lower end of a pitman 33, of which the upper end has a strap 34 embracing an eccentric 35. It is the supporting'and adjusting mechanism for this eccentric which constitutes the present invention, although, as hereinbefore 60 indicated, an eccentric supported and adjustable in like manner may be employed in a sewing machine for actuating an element other than the feed-dog.

According to the construction illustrated in tric 35 surrounds the main shaft 5 and has an enlarged circular shaft-aperture 35, although obviously this aperture may be ovate if preferred. The eccentric 35' has a peripherally indexed end flange 31 comprising, in effect, a disk rotatable with the eccentric. The flange-disk '31 is provided with a pair of diametrically alined and elongated slcts 38 through which pass stud-screws 39 threaded into apertures 89 provided in the beltpulley 6, whereby'the eccentric 35 is secured for rotation with the main shaft 5, but is adjustable radially of the shaft as to eccentricity.

Disposed upon the main-shaft 5, between the flange-disk 31 and the pulley i5, is an adjustingcam or disk 4|, provided with arcuate slots 42 at opposite sides and concentric with the main-shaft 5, said slots 42 receiving and providing clearance for the stud-screws 39 upon relative rotation of the eccentric 35 and the adjusting cam 91. Friction washers 43, interposed between the heads of the stud-screws 39 and the flange-disk 31 serve to yieldingly maintain the eccentric and cam against any substantial movement endwise of the main-shaft 5. Projecting from the adjustingcam side of the flange-disk 31 is a pin 95 carrying a cam-roller 95 entering a cam-groove d6 prcvided in the adjacent side face of the adjusting cam, whereby the eccentric and cam are so connected that relative rotation thereof effects adjustment of the eccentric 35 as to eccentricity.

The adjusting cam All is peripherally provided with a stop-notch 41 adapted to be entered by the nose 39 of a manually operable latch-member in the form of a bell-

crank lever

49, 59, fulcrumed upon a pivot-screw 5| and between spaced ears 52 provided upon the front wall-of the arm standard 2 to receive the pivot-screw. The latch-member arm 49 which has the nose 48 extends into the arm-standard through a suitable slot 53 in the arm-standard front wall, while the arm of said latch-member is flattened to provide a thumbp'iece at the outer side of the arm standard. A spring 54 acts to yieldingly hold the latch-member retracted from engagement with the adjusting cam. When the nose 48 of the latch-member is caused to enter the adjusting-cam notch 41, said adjusting cam is restrained against rotation with the shaft 5 and, consequently, by now turning said shaft 5, the eccentric 35 will be adjusted as to eccentricity.

In prior constructions, reliance has been placed upon the friction washers 93 to maintain the eccentric 95 in adjusted position during the-operation of the machine, 1. e., to maintain unison rotation of the adjusting camfll and eccentric 95. However, at higher speeds of operation and heavy load conditions, a slippage occurs between the eccentric and cam, thereby dislodging the eccentric from set position. This liability to slippage may be overcome up to a'certain speed of operation of the machine by tightly clamping the cam M and eccentric 35 together, by means of'the stud-screws 39. However, when so tightly clamped as to re-- duce liability of slippage between the cam and eccentric during the operation of the machine, it

becomesextremely difjficult to effect adjustment of the eccentric by turning the main-shaft 5, in

a position of the latch-member 89, 50 wherein the cam isrestrained against rotation. I According to the present invention, the eccentric 35 and adjusting cam 4| are normally posietively locked together for unison ,rotation during the operation of the machine, the locking means being readily releasable and preferably simulta- Figs. 1 to 7, inclusive, of the drawings, the eccenneously with theanchoring of the adjusting cam against rotation. To this end, the adjusting cam 41 is provided with a radial aperture 55 opening ed to be engaged by the detent-head 51, said head being shaped to fit the teeth of the rack 59 in poe sitions corresponding to the markings, or index,

upon the periphery of the flange-disk 31. A spring 60 housed in the aperture 55 acts to normally seat the detent in locking engagement with the rack 59. As the detent head 51 extends into the stopnotch 41 of the cam, said detent is also disposed in the path of movement of the latch-member nose 48 into cam-anchoring position."

It will therefore be understood that, while the eccentric and adjusting cam are positively locked against relative slippage during the normal operation of the machine, the latch-member not only serves as means to anchor the cam but simultaneously therewith acts to unseatjthe

detent

56, 51 from the toothed rack 59, so that the main-shaft may be easily turned to eifect'adjustment of the eccentric. It will alsobe'understood that the provision of the positive locking means described eliminates any necessityfor tightly clamping the cam and eccentric together by means of thestudscrews 39, it being merely necessary tb maintain cooperative relationship between said elements.

In the modification illustrated in Figs. 8.to 13 inclusive of they drawings, novel means are provided for securing an eccentric to the actuating diametrically grooving a side face of .a collar 61- secured by set-screws 58 upon the shaft 5, said collar 61 together with the collar 64 also serving to maintain cooperative relationship between the eccentric 6i and cam 63 as to relative movement endwise of the shaft.

As in the construction herein first described, the eccentric-flange 62 carries a cam-roller 59 entering a cam-groove 10 in the adjacent side face of the adjusting cam 63. The adjusting cam 63, likewise, is provided with a spring-pressed detent 11 extending into a stop-notch 1'2 in the periphery of the adjusting cam, said detent normally engaging an arcuate rack 13 in the recessed side face of the eccentric-fiange62 to positively lock the adjusting cam and eccentric for unison rotation during the operation of themachine.

Having thus set forth the nature of the invention, what I claim herein is 1. In a sewing machine, a rotary shaft, an actuating eccentric having an arcuate rack, means for securing said eccentric for rotation with said shaft and'providing for right line adjustment of the eccentric crosswise of the shaft, an adjusting cam rotatablymounted upon said shaft, a connection between said cam and eccentric whereby relative rotation of the cam and eccentric efiects adjustment of the eccentricity of the eccentric, a

the eccentric crosswise of the shaft, an adjusting cam loosely mounted upon said shaft and peripherally provided with a stop-notch, a connection between said cam and eccentric whereby relative rotation of the cam and eccentric effects adjustment of the eccentricity of the eccentric, a springpressed detent carried by said cam for engagement with said rack, said detent in its rack-engaging position extending into said stop-notch of the cam, and a manually operable latch-member adapted to enter the cam stop-notch and shiftably engage said detent, to thereby restrain said cam against rotation and to release said detent.

3. In a feeding mechanism for sewing machines, a rotary shaft, an adjusting cam rotatably disposed upon said shaft and having a peripheral stop notch, a feed actuating eccentric provided with an arcuate rack, said eccentric and rack being disposed at the same side of said adjusting cam, means for securing said eccentric for rotation with said shaft and providing for adjustment of the eccentricity of the eccentric, a connection between said cam and eccentric for effecting adjustment of the eccentric upon relative rotation of the cam and eccentric, a springpressed detent carried by said cam in engagement with said rack to insure unison rotation of the eccentric and cam, and a manually operable latch member adapted. to enter the stop notch of said cam and shiftably engage said detent to release the detent and to restrain said cam against rotation.

d. In a feeding mechanism for sewing machines, a rotary shaft, a feed-actuating eccentric disposed upon said shaft for adjustment as to eccentricity, 'said eccentric having an end flange provided with an arcuate toothed rack, an adjusting cam rotatably disposed upon said shaft adjacent to the eccentric flange, said cam having a radial aperture terminating in a peripheral stopnotch, a spring-pressed detent having a shank slidably disposed in said radial aperture of the cam and having a transverse head positioned in said stop-notch for normal engagement with the teeth of said rack, a connection between said cam and eccentric for effecting adjustment of the eccentric upon relative rotation of the cam and eccentric, means for maintaining said cam and eccentric in cooperativerelation, and a latch-member adapted to be manually operated to enter the stop-notch of said cam and shiftably engage said detent to release the detent and to restrain said cam against rotation.

5. In a sewing machine, a rotary shaft, an ec- 1 centric disposed upon said shaft for radial adjustment, an adjusting cam rotatably mounted upon said shaft adjacent one end of said eccentric, a connection between saidcam and eccentric whereby relative rotation thereof effects adjustment of the eccentric radially of the shaft, and opposed collars secured upon said shaft for restraining said cam and eccentric against movement endwise of said shaft, said eccentric being adjustably keyed to one of said collars to confine Y the eccentric to rotation with said shaft and toprovide for radial adjustment of the eccentric.

6. In a sewing machine, a rotary shaft, an eccentric disposed upon said shaft for radial adjustment, an adjusting cam rotatably mounted upon said shaft adjacent one end of said eccentric, a connection between said cam and eccentric whereby relative rotation thereof effects adjustment of the eccentric radially of the shaft, a collar secured upon said shaft adjacent the end of said eccentric opposite to the cam end thereof, said collar having a tongue-and-groove connection with said eccentric to confine the eccentric to rotation with said shaft, means maintaining said cam and eccentric in cooperative relation, and means normally effective during the operation of the machine to effect rotation of said cam in unison with said eccentric.

7. In a sewing machine, a rotary shaft, an actuating eccentric, means for securing said eccentric for rotation with said shaft and providing for adjustment of the eccentricity of the eccentric, an adjusting cam loosely mounted upon said shaft and operatively connected with said eccentric to efiect adjustment of the eccentricity of the eccentric upon relative rotation of the cam and eccentric, interengaging locking means provided upon said eccentric and cam effective to positively secure said cam for rotation with said eccentric, and manually operable means for effecting release of said locking means.

8. In a sewing machine, a rotary shaft, an actuating eccentric provided with an arcuate rack having its center of curvature non-coincident with the center of curvature of the peripheral face of said eccentric, means for securing said eccentric for rotation with said shaft and providing for adjustment of the eccentricity of the eccentric, an adjusting cam rotatably mounted upon said shaft, a connection between said cam and eccentric whereby relative rotation of the cam and eccentric effects adjustment of the eccentricity of the eccentric, a spring-pressed detent carried by said cam for engagement with said rack, and manually operable means for effecting release of said detent.

JAKE H. S'I'EARNS.