US3094089A

US3094089A - Presser foot

Info

Publication number: US3094089A
Application number: US66995A
Authority: US
Inventors: Shuman Abraham
Original assignee: Individual
Current assignee: Individual
Priority date: 1960-11-03
Filing date: 1960-11-03
Publication date: 1963-06-18
Anticipated expiration: 1980-06-18

Description

June 18, 1963 A. SHUMAN PRESSER FOOT Filed Nov. 3, 1960 INVENTOR. ABRAHAM SHUMAN BY ATTOR Y United States Patent 3,094,089 PRESSER FOOT Abraham Shuman, Union Mill 1, Fall River, Mass. Filed Nov. 3, 1960, Ser. No. 66,995 1 Claim. ((11. 112-435 My present invention relates to sewing machines and more particularly to an improved construction of a presser foot.

The principal object of the present invention is to provide a presser foot which meshes with the feed dog to provide a positive driving action on the material being fed.

Another object of the present invention is to provide a presser foot which virtually eliminates slippage between layers of material passing through the sewing machine.

A further object of the present invention is to provide a presser foot which is particularly designed for light material.

Another object of the present. invention is to provide a presser foot having a positive feed which is simple in construction and easy and economical to manufacture and assemble.

With the above and other objects and advantageous features in view, my invention consists of a novel arrangement of parts more fully disclosed in the detailed description following in conjunction with the accompanying drawings and more particularly defined in the appended claim.

In the drawings,

FIG. 1 is a perspective view of a presser foot embodying my invention.

FIG. 2 is a side elevation thereof partially in section.

FIG. 3 is a section taken on line 33 on FIG. 2.

FIG. 4 is a front elevation thereof.

FIG. 5 is a longitudinal section showing the cooperation between the feed dog and the presser foot.

In a sewing machine, a presser foot is used to apply a vertical pressure to frictionally retain the material in proper position under the needle. A feed dog is positioned under the presser foot. The feed dog is provided with teeth and is cam operated so that it moves upwardly against the material, moves rearwardly to feed the material, then drops and returns to its original position for the next feed. This is timed with the stroke of the needle. Where two layers of material are passing through there is a tendency for the feed dog to feed the lower layer which theoretically carries the upper layer. However, there is always slippage between the two layers so that the operator must exert a separate pull on the upper layer to prevent the slipping of the material.

In my copending application entitled Presser Foot, Serial No. 6990, filed February 5, 1960, I disclose a presser foot which provides for a meshing action between the feed dog and a series of tooth rollers on the presser foot. Thus the feed dog cooperates with these rollers to impart a positive driving action to the upper layer of material. However, the applicant has found that the device shown in his copending application works well with heavier materials but not as efficiently with extremely light materials such as curtain materials and thin silks, rayons, etc. These thin materials have a tendency to slip quite a bit under the presser foot. The presser foot of the present invention has been especially designed to handle extremely light materials.

Referring more in detail to the drawings, the presser foot of the present invention is preferably attached to the sewing machine by a rigid shank having the usual U-shaped slot 111 for attachment to the sewing machine. In my copending application the bottom of the foot is attached to the shank by a pivot pin and spring which permits rocking action. For the purposes of the present invention it has been found desirable that the bottom portion of the presser foot be attached rigidly to the shank 10. The presser foot must be thrown slightly forwardly so as to extend in proper position under the needle, the shank 10 is therefore provided at the bottom end with a short integral neck portion 12 which angles forwardly as shown in FIGS. 1 and 2. The foot itself comprises a rectangular portion 13 which may be formed integrally with the shank 10 and neck :12 or separately attached thereto. At the front the rectangular portion curves downwardly and outwardly to form a pair of spaced feet 14 which may vary in length as illustrated and which curve upwardly at their front edges to permit the material to slide under the foot. The space between the feet'14 forms a slot 15 which extends rearwardly almost to the rectangular portion 13 and a suflicient distance to permit the sewing machine needle shown at 16 in dotted lines to enter the material by passing through the slot 15.

In conventional operation, the bottom of the presser foot would be positioned at right angles to the vertical axis of the shank 10. The metal is highly polished to permit a holding pressure but minimizing the friction.

However, in accordance with the present invention the bottom of the presser foot 17 is formed as shown in FIGS. 2 and 5 with approximately an eight degree pitch forwardly, so that the spaced feet 14 touch the material while the rear portion is slightly raised. In accordance with the present invention the rectangular portion 13 is hollowed out to form a housing 18. The roller 19 is supported on a pivot pin 20 which extends transversely through the side walls of the rectangular portion '13. The roller 19 is provided with teeth 21 which are slanted rearwardly as shown in FIGS. 1, 2 and 5. The roller 19 is so mounted that the outer circumference of the teeth 20 extends approximately .013 inch below the bottom 17 of the presser foot. As can be seen in FIG. 2 this is approximately equivalent to the length of one tooth and the extension approximately compensates for the eight degree lift of the foot at that point. The back of the housing portion 18 is closed by a pivoted door 22 which may be opened to clean dust or lint which may accumulate in the housing and to replace the roller 19.

Referring to FIG. 5, the conventional sewing machine is provided with a plate 23 having a slot or opening 24 extending beneath the presser foot. The cam operated feed dog 25 is provided with teeth 26 which slant rearwardly. The feed dog slides forwardly, then upwardly into the material 27 then rearwardly to feed the material rearwardly then downwardly and forwardly back into the position shown in FIG. 5. In accordance with the present invention the size and spacing of the teeth 20 on the roller 19 is identical with the size and spacing of the teeth 26 on the feed dog 25. Both sets of teeth slant rearwardly. It is obvious that from the position shown in FIG. 5, as the feed dog 25 moves upwardly the material 27 will be pinched between the upper and lower sets of teeth which mesh with each other. Now as the feed dog moves rearwardly the meshing action will rotate the roller 19 and cause both layers of the material 27 to move together without slippage. This movement will pull the material beneath the front of the presser foot which is frictionally engaging the material. The pulling action serves to keep the material taut and flat beneath the presser foot for the smooth entry and retraction of the needle 16. This action is particularly desirable on thin curtain materials, meshes, silks and rayons. These materials have a tendency to slide under the presser foot and to bunch up. The result is that it is diificult to maintain a straight smooth stitch.

As shown in FIG. 3, the rear wall 22 which forms a pivoted closure surrounds the roller 19 so that there is little or no space between the roller and the surrounding wall area. This is necessary to prevent the light material from creeping around the pin and into the housing 18 to snag the material or bunch it up.

The invention is illustrated on a single foot for a single needle machine. However, it can readily be applied to a presser foot for a multi-needle machine.

In use it has been found that the material 27 carries through the machine much more easily than with the conventional presser foot. Accordingly about 25 percent to 35 percent less pressure is required with the presser foot of the present invention. This prevents marking or unduly stretching very fine materials. The reduced presser foot pressure also prolongs the life of the machine. Since the dog must lift against the presser foot, the reduced pressure increases the life of the various bearings and cams. It should be noted that the feed dog 25 is an interchangeable element on a sewing machine. These feed dogs with diiferent size and spacing of teeth are usually changed with dilferent types of material. The length of the feed is also adjustable. While any feed dog will produce the results herein described it is desirable for the best results that the roller teeth and feed dog teeth be identical and complementary to each other. It will therefore be necessary when the feed dog is changed to either change the presser foot or change the roller to conform to the feed dog.

The device of the present invention thus virtually eliminates the slippage problem by providing an intermeshing feed grip between the presser foot and the feed dog which is positively driven by the feed dog. Other advantages of the present invention will be readily apparent to a person skilled in the art.

I claim:

A presser foot for a sewing machine having a feed dog with surface teeth for feeding material to a needle, comprising a vertical shank for attaching the presser foot to a sewing machine, a rectangular housing extending forwardly from the bottom of said shank, said housing having integral side walls, a top wall and a front wall, a pair of spaced parallel feet extending integrally forwardly from the front bottom of said housing, a rear wall on said housing, a transverse shaft mounted in said side walls in said housing, and a roller rotatably mounted on said shaft, said roller having a plurality of longitudinal teeth slanted rearwardly, said teeth extending from the bottom of said housing, said roller teeth being of the same size and spacing as the teeth on the sewing machine feed dog, said roller being positioned over the feed dog of the sewing machine, said teeth meshing with the feed dog to pinch and positively feed the material through the sewing machine on rearward movement of the feed dog, said rear wall being pivotally mounted adjacent its upper edge in said housing and having a forwardly extending flange at its lower edge extending into close proximity to said roller.

References Cited in the file of this patent UNITED STATES PATENTS 1,147,960 Mathewson July 27, 1915 1,850,986 Routtenberg Mar. 22, 1932 2,948,242 Shuman Aug. 9, 1960 FOREIGN PATENTS 879,952 Germany June 18. 1953