US1923080A - Presser-foot for sewing machines - Google Patents

Description

llg- 22, 1.933- A. H. DE voE PRESSER FOOT FOR SEWING MACHINES Filed April 15, 1932 Patented Aug. 22, 1933 UNITED STATES PATENT QFFICE Albert H. De Voe, Westfield, N. J., assigner to The Singer Manufacturing Company, Elizabeth, N. J., a Corporation of New Jersey ApplicationrApril 15, 1932. Serial No. 605,408

14 Claims.

This invention relates to improvements in presser-feet for sewing machines, and has for its primary object to provide a presser-foot of simple construction adapted to effectively accommodate the passage thereunder of uneven thicknesses of work. f A further objectief the'invention is toprovide` improved compensating means for maintaining a substantially constant pressure distribution to relativelyyielding work-engaging sections of a presser-foot.

A preferred embodiment of the invention consists in the devices, combinations and arrangements of parts hereinafter described, in connection with the accompanying drawing, and pointed out in the appended claims.

In the drawing, Fig. 1 represents a view in side elevation of the presser-foot and feed-dog with the work-support in section. Fig. 2 is a top plan view of the presser-foot. Fig. 3 is a view in front elevation of the presser-foot, with the tread-members thereof and the work-support in section substantially on the line 3 3 of Fig. 1, and further illustrating in section aA hem-folded piece of material under the presser-foot. Fig. 4V

is a view similar to Fig. 3, with the section taken substantially on theline 4 4 of Fig. 1. Fig. 5 represents a bottom plan view of the presserfoot. Fig. 6 represents in perspective view the presser-foot parts in detached relationship. Fig. '7 is a top plan view of the throat-plate and feed dog.

The improved presser-foot is particularly adapted for use in hemstitching machines and has been embodied in a chain-stitch hemstitching machine forming the subject of my patent application Serial No. 605,407 filed April 15, 1932, although the present invention `is obviously not limited to the type of machine or the particular embodiment thereof referred to.

The sewing machine in which the present improvement has been embodied includes a clothplate 1, upon which a throat-plate 2 is secured by screws 3. The throat-plate 2 has an auxiliary-piercer aperture 4 in advance of a combination needle-and-piercer slot 5, elongated transversely of the direction of feed to accommodate one or more vertically reciprocatory and laterally vibratory needles 6. Opening into the rearward edge of said slot 5 is a pair of substantially parallel inner feed-slots 7 disposed between outer feedslots 8 at opposite sides of the needle-slot 5. Disposed below the work-support, comprising the cloth-plate 1 and throat-plate 2, is a feed-bar 9 which may be actuated in any suitable manner andcarries a feed-dog 10 having outer rows of work-engaging teeth l1 operating in the feedslots 8 and inner rows of work-engaging teeth 12 operating in the feed-slots 7. v

Opposed to the feed-dog 10 is a presser-foot carried by a vertically' movable presser-bar 13 spring-depressed in any usual or suitable manner (not shown). The presser-foot has a split shank-sleeve 14 clamped by a screw 1,5 upon the lower end of the presser-bar, said shank-sleeve 14 having a shank-bracket 16 shouldered at the rearward portion of its under face to provide a ledge 17. Secured upon the bracket-ledge 17, by screw 18, is a at spring-plate cut away to provide three adjacent'and substantially horizontally disposed spring- tongues 19, and 21, of which the middle tongue 2O is slightly shorter than the outside ones.

Secured to the under face of the forward or free end cf the spring-tongue 19, by screws 22, is a spacing block or lug 23 disposed upon a footplate or tread-member 24 substantially midway of the length thereof. The tread-member 24 is opposed to one of the outer feed-dog members 11, being' disposed entirely at one side of the line of seam formation. Adjacent to said tread-member 24 is a relatively shorter chaining-off treadmember 25 of which the forward end extends approximately to the middle of the length of the tread-member 24 and is provided upon its upper face witha spacing block or lug 26 secured to the under side of the free end of the springtongue 20 by screws 27. The chaining-off treadmember 25 is opposed to the feed-dog members 12 and'is disposed rearwardly of the path of the needle 6. The spring-tongue 21 is likewise secured, at its free end by screws 28, upon a spacing' block or lug 29 upon the upper face of a tread-member 3@ substantially midway between the ends thereof. The tread-member 30 is opposed to the other feed-dog member 11 and overlies that portion of the throat-plate 2 directly in front of the chaining-off tread-member 25 to extend into close proximity to the tread-member 24, said member 3) being partly cut away to provide clearance for the member 25. The treadmember S0 has an auxiliary-piercer aperture 31, and directly rearwardly of said aperture a needle-and-piercer slot 32 open at its rearward edge. Y

By supporting the tread- members 24 and 30 intermediate the endsthereof by the springtongues described, said members are capable of universal yielding and rocking movements independently of each other to accommodate va- -riations in thicknesses of work. The chaining-off member 25 is likewise free to yield independently of the other tread-members. In order to efficiently distribute to the several treadmembers the downward pressure of the pressurebar 13, and to maintain the distributed pressure substantially constant, there is provided a substantially horizontally .disposed compensating member 33 having upon its underface triangularly arranged pointednubs 34, 35 and 36 with each nub bearing upon one of the spring-tongues; The forward nubs 34 and 35 bear upon the springtongues 19 and 2l close to the free ends of said tongues, while the third or rearward nub 36 bears upon the tongue 20 slightly rearwardly beyond the middle of its length. As said nubs bear upon the tongues 19 and 20 or 20 and 2l at different points in the lengths thereof, the chaining-off tread-member 25 is under slightly less pressur than the other tread-members. In order to provide for universal rocking movements of the compensating-member 33, and to transmit vthe pressure of the pressure-bar to the tread-members, a conical pointed screw 37 is vertically threaded into the forward portion of the shank-bracket 16, with the pointed end of said screw projecting below said bracket to freely enter a rounded depression 38 provided in the upper face of the compensating-member 33 substantially centrally of the triangle formed by the nubs 34, 35 and 36 thereof. The screw 3'7 is normally adjustably secured by a nutv 39 in a position such that, when the ),n'esser-foot is raised above the work, the compensating-rnemberv 33 is t spring pressure applied to the presser-bar 13, the

compensating-member 33 rocks about the point of the screw 37 conformably with yielding movements of the individual tread-members to maintain substantially constant pressures exerted by the several tread-members upon the work.

The compensating-member 33 is partly cut away centrally of its front portion to provide for convenientA access to the screws 27 which secure the chaining-01T tread-member to its spring tongue, and the rearward portion of said compensating-member is cut away at opposite sides thereof to provide a narrowed extension or tail 33 disposed between opposed shoulders 40 formed by suitably recessing the underface of the shankbracket 16, The opposed shoulders 40 serve to loosely conne the plate-extension 33 and thereby restrain said plate against any substantial turning in a horizontal plane about the. point of the screw 37, although it is obvious that other equivalent means might be provided for this purpose. It is also obvious that the herein described compensating expedient is readily adaptable for use with more than three tread-members and that other changes may be made all within the spirit and scope of the invention.

Figs. 3 and 4 of the drawing illustrate the iiexibility of the presser-foot, a body-material M being disposed between the presser-foot and worksupport, with a single thickness of the material below the tread-member 24 and a marginal hemvfold under the tread-member 30. The hem-fold presents different thicknesses of work under adjacent portions of the tread-member 30 and it will be observed that said member 30 is slightly tilted in a direction crosswise of the line of seam formation to accommodate this condition, the

spring-tongue 21 being sufficiently torsionally flexible for this purpose. In other words, the tread-members are capable of rocking movements about transverse axes as well as bodily yielding movements, the chaining-off member 25 exerting somewhat less pressure upon the seam than is exerted by the other tread-members upon the work, said tread-member 25 providing for feeding a thread-chain or chains in the absence of work.

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

1. A presser-foot for sewing machines. including'three spring-depressed work-engaging treadmembers, means for supporting said tread-meinbers for relative movements thereof, and compensating means acting upon each of said members for maintaining substantially constant the pressure distribution to said members.

2. A presser-foot for sewing machines, including three work-engaging tread-members, yielding means for depressing said tread-members, and a Y single compensating-member for maintaining the pressure distribution to said tread-members of said yielding means. Y

3. In a sewing machine, a spring depressed presser-bar, a plurality of relatively movable workengaging tread-members, spring means carried by said presser-bar for supporting said treadmembers, and a compensating-member interposed between said presser-bar and tread-members for maintaining substantially constant the pressure distribution to said tread-members.

4. A sewing machine presser-foot having a supporting shank, a plurality of spring-tongues upon said shank, relatively movable tread-members carried by said spring-tongues, and pressure-compensating means interposed between said shank and tread-members.

5. A sewing machine presser-foot having a supporting shank, a plurality of spring tongues extending substantially horizontally from said shank, relatively movable tread-members carried by said tongues, a pressure-compensating member interposed between said shank and tread-members, and means for transmitting pressure to said compensating-member.

6. A sewing machine presser-foot including a plurality lof relatively movable work-engaging tread-members, and a universally rocking pressure-compensating member acting upon said tread-members.

7. A sewing machine presser-foot including three. relatively movable work-engaging treadmembers, and a horizontally-disposed, universally rocking pressure-compensating-member acting upon each of said members.

8. Asewing machine presser-foot having a supporting shank, a plurality of spring tongues extending substantially horizontally from said shank, relatively movable tread-members carried by said tongues, a pressure-compensating member disposed to engage said spring tongues, and means confining said compensating-member against edgewise movement and providing for universal rocking movements of the compensating-member.

9. A sewing machine presser-foot having a supporting shank, a plurality of spring tongues extending substantially horizontally from said shank, relatively movable tread-members carried by said tongues, a horizontally disposed pressurecompensating member interposed between said shank and tread-members having in one face thereof a recess, and ia compensating-member anchoring element entering said recess providing for universal rocking movements of said compensating-member.

10. A spring-depressed presser-foot for sewing machines having a supporting shank, a plurality of spring tongues extending from said shank, relatively movable tread-members carried by said tongues, and means for distributing pressure to said tread-members including a pressure-compensating member disposed to engage said tongues at different points in the lengths of a pair of tongues.

11. A spring-depressed presser-foot for sewing machines having a plurality of relatively movable, work-engaging tread-members, a treadmember supporting shank, a pressure-compensating member having triangularly arranged nubs disposed to distribute pressure to said tread-members, and a pressure-transmitting element carried by said shank engaging said compensating-member substantially centrally of the triangularly arranged nubs thereof.

12. A spring-depressed presser-foot for sewing machines, comprising a supporting shank, a plurality of spring-tongues extending substantially horizontally from said shank, relatively movable tread-members carried by said tongues at the free ends thereof, a pressure-compensating memberrhaving a plurality of nubs each engaging one of said tongues, and a pressure-transmitting screw adjustably secured upon said shank in position to engage said compensatingmember.

13. In a sewing machine, a reciprocatory needle, a spring-depressed presser-foot having a pair of work-engaging relatively movable treadmembers including a chaining-off tread-member disposed rearward of the path of said needle, and compensating means arranged to distribute to a pair of said tread-members pressures of unequal degree and to maintain the relative pressures substantially constant in relative movements of said tread-members to accommodate different thicknesses of work.

14. In a sewing machine, a reoiprocatory needle, a spring-depressed presser-foot having a pair of relatively movable tread-members, a chaining-off tread-member disposed rearward of the path of said needle between and relative'- ly movable with respect to the tread-members of said pair, and compensating means acting upon each of said members maintaining substantially constant the relative pressure distribution to said members.

ALBERT H. DE VOE.

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