US2330177A

US2330177A - Feeding mechanism for sewing machines

Info

Publication number: US2330177A
Application number: US416437A
Authority: US
Inventors: John D Karle
Original assignee: Singer Co
Current assignee: Singer Co
Priority date: 1941-10-25
Filing date: 1941-10-25
Publication date: 1943-09-21
Anticipated expiration: 1960-09-21

Description

.JQ D, KARLE4 2,330,177

FEEDING MECHANISM FOR SEWING MACHINES Filed oct. 25, 1941 I 2 sheets-sheet 1 3mm fo/'m D. Kode Sept. 21, 1943. J. D. KARLE FEEDING MECHANISM FOR SEWING MACHINES 2 Sheets-Sheet 2 Filed Oct. 25, 1941 Patented Sept. 21, 1943 s rename ME CHANISM ron snwiNG MACHINES e John- D1. Karle, Rcseile` Park, YJ., assignor to The Singer. Manufacturing VCompany,

Elizabeth, N. J., a corporation of New Jersey Applicatien- October `25, 1941, SeriaiNo. 416,437

5 Claims.

1 This invention relates to sewing machines'and more particularly to a` feedingA mechanism lthere- (Cl.V 112-215) sition vwhile it is feeding the'work so that all of the feed-dog teeth will uniformly feed the work. y

With the above and other objects in View, as will hereinafterappear, the invention comprises the arrangements of parts hereinafter set forth and illustrated in the accompanyingdrawings of a preferred embodiment of the invention, from which the several features of the invention and the advantages attained thereby'will be readily understood by thoseskilled inthe art.

In the accompanying drawings, Fig. 1 isa side elevation, partly in section, of a sewing machine having my improved feeding mechanism embodied therein.

Fig. `2 is a bottomAV plan-view to 'disclose the mechanism beneath the bed.

Fig. 3 isy an endelevation of the machine looking from the left of Fig. 1.

Fig. 4 is a diagrammatic view of the feedactuating eccentrics disclosing their phase relation.

Fig. 5 is an enlarged fragmentary view of the feed-bar.

In the embodiment of the invention selected for illustration, Ill is the sewing machine bed to which is secured the overhanging frame or gooseneck II which terminates in a hollow head I2. Journaled in the spaced bearings I3 and I4 in the frame I I is a needle-bar and feed driving-shaft I5 having the usual balance-wheel I6 fixed to the rear end thereof. At its forward end, the shaft I5 actuates, through suitable mechanism carried in the hollow-head I2, a reciprocatory needle-bar Il which carries, at its lower end, an eye-pointed needle I8. Also carried in the hollow-head I2 is the usual springpressed presser-bar I9 to the lower-end of which is secured, as by a clamp-screw 20, the upright shank ZI of the hinged presser-foot 22.

Journaled in

bearings

23 and 24 carried by the bed I is the usual rotary hook-actuating shaft 25. To the forward end of the shaft 25 is secured the usual hook element 26 which is complemental to the needle I8 in the formation of stitches. This bottom shaft 25 is driven from the top shaft I through the upright shaft 26 which is journaled in the bearing lugs 21 and 28 cast in the frame Il. The top shaft I5 has fixed yto it 'a bevel gear 29 which mesheswith a bevel gear 30 xed to'thetop end of the upright shaft 26. The bottom shaft 2-5 carries a bevel gear 3i which meshes with a bevel gear 32 fixed to the lower endof the upright shaft 2'6. v j

The top-shaft I5 carries the usual work-feeding eccentrics 33 and :34, which actuate the usual pitman rods 35V and36 connected respectively to the rock-shafts 31 and 3B. Rock-shaft 38y imparts the rising and falling movements androck-shaft 3%l`imparts the feed-advance and -return movements to thev feed-dog which will hereinafter be described. For a more detailed description of the present feed eccentrics andthe pitman'con-A nections reference may be Ahad to Patent Nol 2,161,579, to Kaier, dated June 6, 1939.

Secured to one end of' the rock-shaft 3l is a feed-rocker A33 which is f rocked back-and-ferth by thepitman 35. Oneendof a feed-baum;I carrying a 'feeddog 4I is pivotally` connectedto this feed-rocker 39 and its other end is formedas a fork 42 which is provided with an arcuately shaped slot 43. -Slidingly engagingthe slot43-a're V the broad bearing surfaces of a ccrrespondingly arcuately shaped wear-block 44 which is pivotally mounted upon the pin 45 carried by the feed-lift crank 46. This feed-lift crank 46 is fixed to the rock-shaft 33 which oscillates the crank up and down and thereby imparts rising and falling movements to the feed-dog 4 I.

The feed-actuating eccentrics 34 and 35 are disposed relative to each other so that they are substantially out of phase. This phase relation of the eccentrics will effect a timed relation between the rising-and-falling and backwardand-forward movements of the feed-bar, and consequently of the feed-dog, such as are common to so-called four-motioned feeding mechanisms.

In this type of feeding mechanism it is desirable to have the feed-dog feeding surface parallel to the sewing machine working surface while the feed-dog is in contact with the work advanced thereby. I-Ieretofore, Vin sewing machines using the present type of four-motioned feeding mechanisms having the usual feed-rocker and feed-lift crank, the feed-dog begins to drop when the feed-lift eccentric has passed through its uppermost dead center position. At this time the feed-dog is moving from front to rear in its work feeding stroke. To counteract this condition in the present construction, I have provided in the feed-bar fork 42, a slot 43 having side-walls formed as the arcs of two concentric circles. As may be seen in Figs. 3 and 5, the slot 43 is curved downwardly towards the feed-lift crank 46, and the center of curvature C of the slot 43 lies at a. level below the feed-bar 4U, as indicated in Fig. 5.

It is the function of the arcuately shaped slot 43 to eieot an accelerated rising movement in the fork 42, relative to the feed-lift crank`46, as the feed-advance rocker 39 moves the feed-bar 40 from front to rear. It is this rising movement of the fork 42, relative to the crank 46, that compensates for the accelerated drop of the crank 46 and thus maintains a substantially parallel relation between the feeding surface of the feeddog 4| and the machine working surface for a prolonged portion of the feed-stroke of the feeddog 4 I. In the present illustrated sewing machine the working surface level is represented by the top of the throat-plate 41.

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

1. A work-feeding mechanism for sewing machines comprising, a feed-bar, a feed-dog carried by said feed-bar, one end of said feed-bar being provided with an arcuate slot, the center of curvature of said slot lying below said feed-bar, means operatively engaging said-arcuate slot for imparting rising and falling movements to said feed-dog, and means operatively connected to the other end of said feed-bar for imparting work-advancing and -return movements to said feed-dog.

2. A feeding mechanism for sewing machines comprising, a feed-bar, a feed-dog carried by said feed-bar, means operatively connected to one end of said feed-bar for imparting work-advancing and -return movements to said feed-dog, and means including a member having a bearingportion shaped as an arc of a circle slidingly engaging the other end of said feed-bar for the purpose cf imparting rising and falling movements to said feed-dog, the center of curvature of said arc lying at a point below the level of said feed-bar. l

3. A work-feeding mechanism for sewing machines comprising, a feed-bar, a feed-dog carried by said feed-bar, a fork carried by one end of said feed-bar and having an arcuate slot formed therein, an oscillating crank, a wearblock pivotally carried by one end of said crank and slidingly engaging said arcuate slot for the 5 purpose of imparting rising `and falling movements to said feed-dog, said slot being inclined downwardly towards said oscillating crank and having its center of curvature disposed at a point below the level of said feed-bar, and means operatively connected to the other end of said feedbar for imparting work-advancing and -return movements to said feed-dog.

4. A work-feeding mechanism for sewing machines comprising, a feed-rocker, a feed-bar having one of its ends pivoted to said feed-rocker,

a feed-dog carried by said feed-bar, a fork carried by the other end of said feed-bar and having an arcuate slot formed therein, an oscillating feed-lift crank, and a block pivotally carried by one end of said crank and slidingly engaging said arcuate slot, said arcuate slot being inclined downwardly towards said oscillating feed-lift crank and having its center of curvature disposed at a point below the level of said feed-bar.

5. In a sewing machine having a framaa rotatable feed-actuating shaft journaled in said frame, a pair of eccentrics mounted upon said feed-actuating shaft and disposed substantially 90 out of phase relative to each other, a feed- A rocker carried by said frame and actuated by one of said eccentrics, a feed-bar having one of its ends pvotally connected to said feed-rocker, a feed-dog carried by said feed-bar, and an oscillating feed-lift crank actuated by the other eccentric and operatively engaging the other end of said feed-bar; the improvement which consists in the provision in the feed-bar of a fork having an arcuate slot, and an arcuately shaped block pivotalfly carried by said feed-lift crank and slidingly engaging said arcuate slot, said arcuate slot being inclined downwardly towards said feedlift crank and having its center of curvature disposed at a point below the level of said feed-bar.

JOHN D.