US2509596A - Work feeding mechanism for sewing machines - Google Patents

Description

ma 30 1950 A. N. MAME mm.

WORK FEEDING MECHANISM FOR SEEING MACHINES Film vDem. 25, 1948 .3 $heets-Sheec J.

w WW A. N. HALE mm. 2,5095

woax FEEDING MECHANISM FOR SEWING MACHINES Filezdflec. 23, 1948 3 Sheets-Sheet 3 i A1 i f f$ i $1 Ill ll gg f Patented May 30, 1950 PATENT OFF! CE WORK FEEDING MECHANISM FOR SEWING MACHINES Arthur N. Hale,

Stratford, and Russell Car- Application December 23, 1948, Serial No. 66,924

12 Claims. 1

This invention relates to sewing machines and more particularly to work-feeding mechanisms for ornamental stitching machines of the type disclosed for example in the U. S. patents of F. M. Card, No. 2,216,696, issued Sept. 24, 1940, and C. M. Ambercrombic, No. 1,012,182, issued Dec. 19, 1911.

The primary object of the present invention is to provide an improved quiet running highspeed work-feeding mechanism adapted for feeding the work in opposite directions in a predetermined sequence.

The foregoing and other objects and advantages, together with means whereby the same may be carried into effect, will best be understood from the following description of a preferred embodiment thereof illustrated in the accompanying drawings, in which:

Fig. 1 is a bottom plan View of the bed of a sewing machine equipped with the improved work-feeding mechanism.

Fig. 2 represents an enlarged transverse vertical section taken substantially along the line 2-2, Fi 1.

Fig. 3 represents a horizontal section taken substantially along the line 3-3, Fig. 2, showing the orientation of the feed-bars and their feed-dogs.

Fig. i represents a longitudinal vertical section taken substantially along the line 4-4, Fig. 2.

Fig. 5 represents a transverse vertical section taken substantially along the line 55, Fig. 4.

Fig. 6 represents a vertical section taken substantially along the line ii-6, Fig. 4.

Fig. 7 represents a vertical section taken substantially alon the line 1-1, Fig. 4.

The sewing machine illustrated in the accompanying drawings has the usual bed Ill in which is journaled a rotary bed-shaft ll driven by a belt [2 from a main arm-shaft (not shown) located in the machine-arrn. Operatively connected to the rotary bed-shaft ll through the gear-box i3 is a loop-taker M in the form of a rotary hook complemental to a thread-carrying needle 55 carried in the lower end of a needlebar it (Fig. 2) journaled for endwise reciprocation in the overhanging bracket-arm (not shown). The work to be stitched is depressed into contact with a throat-plate H by a presserfoot is carried on the lower end of a springpressed presser-bar l9 endwise slidalole in the overhanging bracket-arm.

Opposing the presser-foot 18 in feeding the work are two feed-dogs 2B and. 21. In the mathe two feed-dogsare actuatedin a manner suchthat the feed-dog 2D- advances the work; inone direction twice in succession,- following which the feed-dog 21 returns the work once in the opposite direction, this sequence of feeding strokes being used particularly in the production of fagoting and hem-stitching. The feed-dog 24] is secured, preferably by screws 22 (Fig. 3), to a feed-bar 23 pivotally connectedat one end by pintles 24 to the upper ends of a pair of rock-arms 25 preferably integral with a feed' advance rock-shaft 2% supported on pintles 21 to extend longitudinally of the bed Ill. The feed-advance rock-shaft 25 is actuated by means of a rock-lever 28 which is clamped on the reduced inner end of the rock-shaft 26 and connected by a pitrnan 2t to an adjustable eccentric Sil fast on the rotary bed-shaft H. The eccentric 3!! is of well known design and is constructed substantially in accordance with the disclosure in the U. S patent of W. Myers, No. 2,128,031, granted Aug. 23, 1938. Rotation of the bed-shaft ii will impart an oscillatory movement to the rock-shaft 26, thus causing the feed-dog 20 to undergo feed-advance and -Ieturn motions.

The feed-dog M (Fig. 3) is secured, preferably by screws 31, on a second feed-bar 32 pivotally connected at one end' by a pin 33 to the upper end of a rock-lever 34' preferably integral with a second feed-advance rock-shaft 35 supported on pintles 36' to extend longitudinally of the bed H! and in substantially parallel relation with the first feed-advance rock-shaft 26. At its inner end, the second feed-advance" rock-shaft 35 has clamped on it a rock-lever 3? connected bya pitman 38 to a second adjustable eccentric 39 also fast on the rotary bed-shaft H It will be un-- derstood that rotation of the bed-shaft H will also oscillate the rock-shaft 35 and through the 39. Thus, it Will be obvious that during the ad vancing st'rokeof the feed-dog 20- in a direction away from the operator, the feed-dog 21 is undergoing an advancing strokein the direction" of 1 theoperator.

in order that each of the feed-dogs 25 and 2| will be effective in proper sequence, means are provided whereby each of the feed-dogs is periodically raised to a height in which its serrated surface is above the level of the top of the throat-plate ll. When this occurs the feeddog grips the work in opposition to the presserfoot l3 and advances it an amount determined by the set eccentricity of the actuating eccentric. It will be observed in the drawings that the feedbars 23 and 32 are forked as at at and ii at front ends to embrace slide- blocks 42 and 45 pivoted on the free ends of a pair of lift rockarms 34 and i5 clamped n the ends of a pair of coaxially and telescopically disposed feed-lift rock-shafts it and 47. The outer feed-lift rockshaft 46 is journaled on the inner feed-lift rockshaft 47 which is supported by pintles 33 secured in the bed lll. Adjacent the standard-end of the machine, the coaxial feed-lift rock-shafts 36 and i! have clamped thereon a pair of rock-levers 49 and 55. At their free ends each of these rock-levers carries a follower roller 52 yieldingly held by the coil-springs 53, 5c in peripheral contact with suitable lift- cams 55, 55 mounted on a rotary countershaft 5i journaled in bearings 58 and 59 provided in the bed it. The countershaft 57 is driven from the bed-shaft |i through the reduction gears 5t and ill, the gear ratio being such that the countershaft rotates once for each three rotations of the bed-shaft ll. It will be observed from Fig. 7 that the cam 55 has two lobes and that the cam 55 has only one lobe, the two cams being so mounted on the countershaft 57 (Fig. 6) that the three cam-lobes are spaced from each other 120 circumferentially of the counter-shaft 51. Upon operation of the machine, the follower-rollers 5| or 52 ride on their respective cam-lobes and the rock- shafts 46 and 37 are caused to turn about the alined axes of the two pintles 48 and, through the rock-arms 4 3 and 45, raise the feed-dogs 25 and 2| above the throat-plate ll into effective workfeeding position. In the preferred embodiment of the invention, the speed ratio between the countershaft 57 and the rotary bed-shaft H is determined by the total number of feeding strokes of both feed-dogs in producing the desired stitch-pattern. In the machine illustrated in the drawings, the stitch-pattern comprises three feeding strokes, two forward and one backward, and therefore the speed ratio between the countershaft 51 and bed-shaft H is three-to-one. In the event the stitch pattern required a total of four stitches per pattern the speed ratio would then be correspondingly changed.

From the above description, it will be understood that during the operation of the machine, rotation of the bed-shaft M will, through the medium of the adjustable eccentrics 35 and 39, impart continuous feed-advance and -return movements to each of the feed-dogs 20 and 2|. During this continued action of the feed-dogs 2B and 2| they are periodically elevated into effective position by the lift- cams 55 and 56 against the action of the coil- springs 53 and 56. Liftcam 55 is formed with two lobes while lift-cam 56 is formed with only one lobe, and since these lobes are circumferentially spaced 120 degrees apart on the eountershaft 571 which makes only one revolution for each three reciprocations of the needle, it follows that the feed-dog 20 is rendered effective for two successive stitches following which the feed-dog 2| is rendered effective for only one stitch. Inasmuch as the adjustable eccentrics 30 and 35 are degrees out of phase, the feed-dogs 25 and 2| are effective to feed the work in opposite directions. The setting of the present machine is such that the feed-dog 20 advances the work for two stitch-lengths in a direction away from the operator, while the feeddog 2| returns the work a single stitch-length towards the operator. The amplitudes of the work-advancing movements imparted by the dogs 25 and 2| can be individually controlled by the separate adjustment of the eccentrics 35 and 39, and to facilitate this adjustment there are provided two spring-elevated detents 62 and 63 which can be manually depressed to lock the adjusting members of the eccentrics in the manner fully explained in the above mentioned Myers patent.

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

1. A work-feeding mechanism for sewing machines comprising a pair of feed-dogs, a pair of feed-advance and -return eccentrics, a first shaft carrying said eccentrics, operating connections between said feed-dogs and eccentrics, feed-lift mechanism including a cam for each of said feeddogs, and a second shaft carrying said cams and operated at a speed different from that of said first shaft.

2. A work-feeding mechanism for sewing machines comprising a pair of feed-dogs, a pair of feed-advance and -return eccentrics, a first shaft carrying said eccentrics, operating connections between said feed-dogs and eccentrics, feed-lift mechanism including a cam for each of said feeddogs, and a second shaft carrying said cams and operatively connected to said first shaft to rotate at a speed less than said first shaft.

3. A work-feeding mechanism for sewing machines comprising a pair of feed-dogs, a pair of feed-advance and -return eccentrics, a first shaft carrying said eccentrics, operating connections between said feed-dogs and eccentrics, feed-lift mechanism including a cam for each of said feeddogs, a second shaft carrying said cams, and gearing operatively connecting said second shaft to said first shaft for rotating said second shaft at a lesser speed than said first shaft.

4. A work-feeding mechanism for sewing machines comprising a pair of feed-dogs, a pair of feed-advance and return eccentrics, a first shaft carrying said eccentrics, operating connections between said'feed-dogs and eccentrics, feed-lift mechanism including a cam for each of said feeddogs, one of said cams having a plurality of feeddog lifting lobes and the other of said cams having a lesser number of feedlog lifting lobes, and a second shaft carrying said cams and operated at a speed less than that of said first shaft.

5. A work-feeding mechanism, for sewing machines comprising a pair of feed-dogs, an actuating shaft, a pair of feed-advance and -return eccentrics mounted on said shaft with their maximum eccentricities spaced apart circumferentially of said shaft, operating connections between said feed-dogs and eccentrics, and feedlift mechanism operatively connected to said feed-dogs for elevating said feed-dogs into effective work-feeding position.

6. A work-feeding mechanism for sewing machines comprising a pair of feed-dogs, an actuating shaft, a pair of feed-advance and -return eccentrics mounted on said shaft with their maximum eccentricities spaced apart circumferentially of said shaft, operating connections between said feed-dogs and eccentrics, and feedlift mechanism including a cam for each of said feed-dogs for elevating said feed-dogs into effective work-feeding position, said cams timed to successively render eifective one of said feeddogs a plurality of times following which the other feed-dog is rendered effective for a lesser number of times.

7. A work-feeding mechanism for sewing machines comprising a pair of feed-dogs, a rotary actuating shaft, a pair of feed-advance and return eccentrics carried by said rotary actuating shaft, operative connections between said eccentrics and feed-dogs, a pair of feed-lift rockshafts operatively connected to said feed-dogs, a countershaft driven at a speed different from that of said rotary actuating shaft, a pair of feed-lift cams mounted on said countershaft, and a rock-lever connected to each of said feed-lift rock-shafts and engaging its respective cam on said countershaft.

8. A work-feeding mechanism for sewing machines comprising a pair of feed-dogs, a pair of rotary feed-advance and -return eccentrics, feeddog operating devices connected to said eccentrics, a pair of coaxially arranged feed-lift rockshafts operatively connected to said feed-dogs, a countershaft connected to be driven at a speed difierent from that of said rotary eccentrics, a pair of feed-lift cams mounted on said countershaft, and a rock-lever secured to each of said feed-lift rock-shafts and engaging its respective cam on said countershaft.

9. A work-feeding mechanism for sewing machines comprising a pair of feed-dogs, a pair of rotary feed-advance and -return eccentrics, feeddog operating devices including a pair of substantially parallel feed-advance rock-shafts connected to said eccentrics, a pair of coaxially arranged feed-lift rock-shafts operatively connected to said feed-dogs, a countershaft connected to be driven at a speed different from that of said rotary eccentrics, a pair of feed-lift cams mounted on said countershaft, and a rocklever secured to each of said rock-shafts and engaging its respective cam on said countershaft.

' 10. A work-feeding mechanism for sewing machines comprising a pair of feed-dogs, a. rotary actuating shaft, a pair of feed-advance and -return eccentrics mounted on said shaft with their maximum eccentricities spaced apart circumferentially of said shafts, feed-dog operating devices including a pair of feed-advance rockshafts connected to said eccentrics, a pair of coaxially arranged feed-1ift rock-shafts operatively connected to said feed-dogs, a countershaft geared to said rotary actuating shaft to be driven at a speed different from that of said actuating shaft, a pair of feed-lift cams mounted on said countershaft, and a rock-lever secured to each of said rock-shafts and engaging its respective cam on said countershaft.

11. A work-feeding mechanism for sewing machines comprising a pair of feed-dogs having oppositely directed effective Work-advancing movements, an actuating shaft, a pair of feedadvance and -return eccentrics mounted on said shaft with their maximum eccentricities spaced apart circumferentially of said shaft, feed-dog operating devices connected to said eccentrics, and feed-lift mechanism operatively connected to said feed-dogs and timed in its effective action for sequentially rendering said feed-dogs effective in feeding the work in opposite directions.

12. Work-feeding mechanism for sewing machines, including a work-support, comprising, a pair of feed-dogs having oppositely directed effective work-advancing movements through said work-support, operative mechanism for imparting feed-advance and return movements to said feed-dogs, and feed-lift actuating mechanism including a plurality of cams operatively connected to said feed-dogs and timed to effect work-advancing movements of one of said feed-dogs during ineffective return movements of the other 01. said feed-dogs.

ARTHUR N. HALE. RUSSELL CARMICHAEL.

No references cited.

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