US2515513A

US2515513A - Reversible feed mechanism for sewing machines

Info

Publication number: US2515513A
Application number: US652711A
Authority: US
Inventors: Heggie James
Original assignee: Singer Co
Current assignee: Singer Co
Priority date: 1945-03-24
Filing date: 1946-03-07
Publication date: 1950-07-18
Anticipated expiration: 1967-07-18

Description

July 18, 1950 J. HEGGIE REVERSIBLE FEED MECHANISM FOR SEWING MACHINES Filed March 7, 1946 3 Sheets-Sheet 1 gwvmbov Cfwmas 92 369 7 J. HEGGIE REVERSIBLE FEED MECHANISM FOR SEWING MACHINES July 18, 1950 3 Sheets-Sheet 2 Filed March '7, 1946 July 18, 1950 J. HEGGIE 2,515,513

REVERSIBLE FEED MECHANISM-FOR SEWING MACHINES Filed March 7, 1946 3 Sheets-Sheet 3' abkOZ/M/GW Patented July 18, 1950 REVERSIBLE FEED MECHANISM FOR SEWING MACHINES James Heggie, Clydebank, Scotland, assignor to TheSingerManufacturingCompany, Elizabeth, N. J a corporation of New Jersey Application Marchl, 1946,. Serial.No. 652,711

In-Great Britain Marcln24, 1945 4 Claims. (cilia-210) Thi invention relates. to improvements in reversible feed mechanism for sewing machines.

The invention is concerned with four motion feedmechanism. of the typ including a work-engaging feed dog having operative connections with a feed advancerock shaft. and with a feed lift rock shaft'which are located below the machinebed-plate and to which rocking movements are-communicated.

Reversible feed mechanism according, to the invention includes a normally stationary guide block angularly adjustable about an axis parallel to'said'rockshafts, said block. presenting a curved slot, an arm *operatively connected to the feed advance rock shaft, a follower on said arm, said. follower engaging said slot, and, means for effecting angular adjustment of said guide block wherebyto cause reversal of the direction of feed.

In the accompanying drawings Fig. 1 is aview of the'underside of'thebed-plate, of. a sewing. machine embodying reversible feed mechanism according to theinventic-n; Fig. 2 is a vertical sectional View through the machine bed-plate and partly through the standard ofv the sewing machine bracket arm, 1ooking from the head end towards the driving end of the machine, the section being mainly on the lineIIl1 of-Fig. l, and the movable parts of the mechanism being shown as for forward feeding movement; Fig. 3 is a fragmentary head end view showing the conventional four-'moti'on mechanism; Fig. 4 is a view similar to Fig. 2. but showing certain of the parts in a differentposition of operation; Figs. 5 and 6 are similar views to Figs. 2 and 4, respectively, but showing the mechanism disposed as for reverse feeding movement. Fig. 7 is a perspective. view-of parts of the 'feed advan'c'e mechanism, hereinafter to be described.

Referringto thedrawings, 1 denotes the standard of the usual bracket arm uprising from the bed-plate. 2. of a conventional type of lock-stitch sewing machine having an upper rotary needleactuating shaft 3 and a lower rotary loop-taker shaft 4 carrying a loop-taker 4'.

The work-feeding mechanism includes a workengaging feed dog 5 carried by the usual feedbar I, which is pivotally connected :at 8 to an upstanding arm 9 secured on a feed advance rock shaft |0 journalled below the bed-plate '2, and which is provided at its opposite end with a slot engaged by a slide block |'2 on an arm l3 secured on a feed-lift rock shaft Ill. The rock shafts l0, M are given their rocking movements by pitmans I5, I 6 operated, for example, from eccentrics, as II, on the upper shaft 3. The lower end of the pitman I5 is pivotally-connected to an arm. H of a U-shaped follower H which in turn is pivotally connected. at IT between 'tworadial arms |8 provided by a member Hl secured on the shaft I'll. (See Fig. 1..) The lower end of thep'itman I6 is pivotally connected to an arm 20 se cured on the rock shaft l'4.

' Referring now to the feed reversing means of the machine, 2| denotes a normally stationary slotted guide block member presenting an arcuate slot 22 and carried by a short shaft 23' journalled beneath the bed-plate 2 in parallelism with the rock shafts l0, M. The construction is such that the'guid'e block. member?! may be adjusted angularly about "the axis of the shaft 2 3..by means. operable from above'thebed-pl'ate 2, was to effect reversal of the direction of feed...

The slot 22in the guide block member 2| is engaged by a follower stud orroller 24 on the free end of a relatively long arm 25 formingpart of the follower j In the normal actuation of the machine the setting'of the guideblock member 2| is suchthat the axis of curvature Of the'slot 22 in the member 2'1 is almost coincident. with the axis of the feed advance rock shaft l0. Under. these conditions the forward feed motion is obtained.

i When itis" desired to effect reversal of thedirectionof feed, theguide block member 2| is turned through a predetermined'angle into re.- verse setting as'shown in Figs. 5 and 6 in which its axis of curvature is located considerably above the axis of'the feed advance rockshaft l0. Asa result of this adjustment of the guide block member 21 reversal of the direction of feed is 10btained, the follower roller 24 being constrained by the slot 22. to impart reverse feed movement to the feed'advance rock shaft l 0. For effecting adjustment of the guide block member 2| there is provided aplungerf26 guided in an aperture in the bed-plate 2 and adapted to be depressed manually against spring action in order to effect reversal of the direction of feed. The lower end of the plunger 26 is pivotally connected to the mid or free pivot 21 of a pair of toggle levers 28, 29 one 28 of which is pivotally connected at 30 to the guide block member 2| and the other 29 of which has a stationary pivot 3| carried by a member 3| rigidly connected with the bed-plate 2. The toggle lever '29 is influenced by a spring 32 which tends to retain the

toggle levers

28, 29 in straightened condition, 1. e., in the position in which the guide block member 2| is set in normal or forward feed position. When the toggle is broken by depression of the plunger 26, the

guide block member 2 l is set in reverse feed position. When the plunger 2 B is freed the feed mechanism is restored to forward feed position by the action of the spring 32. If desired, a manually operable detent may be provided for engagement with the plunger '26 to hold the mechanism in reverse position.

Stops

33, 34 and an adjustable stop 35 are provided to limit the range of travel of the toggle levers 28, '29 and of the guide block member 2|.

In the present construction the plunger pro.- jects through the bed-plate for convenient ac-' cess. It may, however, be found convenient to arrange the plunger to project to the front of the machine below the bed-plate. I

It is to be understood that while the drawings show an upper shaft connected by pitmans with the feed advance rock shaft and the feed lift rock shaft, these rock shafts may derive their rocking movements from a shaft located beneath the bedplateu As illustrated in the drawings, the feeding mechanism is given its maximum movements in 'fdrward and reverse directions. It is to be un derstood, however, that the length of the feeding stroke is dependent upon the length of endwi'se reciprocation given to the pitman by its actuating eccentric. In machines wherein it is desiredto vary the length of the feed, as Well as to reverse its direction, any conventional or preferred form of adjustable eccentric device ma be employedto variably reciprocate the pitman l5. .1, WhatI claim is:

1. In a sewing machine having a bed-plate; work-feeding mechanism below said bed-plateineluding a feed-dog, a feed advance rock shaft and a feed lift rock shaft, connections between said shafts and said feed dog for imparting'a fourmotion movement to said feed dog, means including anoscillatory actuating arm, having an axis of oscillation located above and connected with the feed advance rock shaft, for communicating rockingmovements to said feed advance rock shaft, means forcommunicating rocking movement to said feed lift rock shaft, a normally stationary guide block located beneath said bed-plate and angularly' adjustable about an aXis parallel to said rock shafts, said block presenting a curved slot of which the axis of curvature is normally eccentric to the axis ofoscillation of said arm, a follower roller on said arm, saidfollower roller engagingsaid slot, and means for effecting angularacljustment of said block about its axis to effectreversal of the direction of feed.

2. In a sewing machine, work-feeding mechanism as claimed in claim 1 in which the means for effecting angular adjustment of the guide block includes a spring-biased toggle .leverdevice having one end pivoted to a memberrigidly connected with the bed-plate and its other end pivotally connected to said. block, said toggle lever device being adapted to be broken against spring action, thereby to change the angular position of said block, when it is desired to effect reversal of the direction of feed.

3. In a sewing machine, work-feeding mechanism as claimed in claim 1 in which the means for effecting angular adjustment of the guide block includes a spring-biased toggle lever device having one end pivoted to a member rigidly connected with the bed-plate and its other end pivotally connected with said block, said toggle lever 'device' being adapted to be broken against spring action, thereby to change the angular position of said block, when it is desired to effect re versal of the direction of feed, and in which the means for breaking the toggle lever device comprises amanually operable member having its lower end pivotally connected to said toggle lever device and its upper end projecting upwardly through said bed-plate: for engagement by the machine operator.

4. In a sewing machine having a frame, including a bed-plate and an overhangin bracketarm, and a rotary shaft journaled lengthwise of said bracket-arm; a work-feeding mechanism comprising a horizontally disposed feed-bar located beneath said bed-plate and carrying a feeddog, means to elevate and depress said feed-bar, means to reciprocate said feed-barrincluding an eccentric on said shaft, a feed advance rock shaft journaled beneath said bed-plate, an arm on said feed advance rock shaft operatively connected to said feed-bar, a member secured on said rock shaft and having two radial arms, a U-shaped follower pivotally mounted between said radial arms and having a pair of arms of unequal length, an upright pitman having its upper end surrounding said eccentric and its lower end pivotally connected to the shorter arm of said U-shaped follower to oscillate said follower, a normall stationary guide block located beneath said bedplate and angularly adjustable about an axis parallel to said rock shaft, said block being provided with a slot having curved walls, a roller carried by the free end of the longer arm of said follower and located between the walls of said slot, said walls normally being at an angle to an arc swung from the pivotal axis of said U-shaped member and acting on said roller to effect oscillatory movements of said feed advance rock shaft, and means for effecting angular adjustment of said block about its axis to effect reversal of the direction of feed.

JAMES I-IEGGIE,

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,341,388 Y Smith May 25, 1920