US2892429A - Presser foot for sewing machines - Google Patents

Description

June 30, 1959 D. FISCHBEIN PRESSER FOOT FOR SEWING MACHINES Filed Aug. 15, 1955 FIG.2

INVENTOR. DAVE- FISCHBEIN WM/K/ FIG. 6

ATTORNEY- United States Patent PRESSER FOOT FOR SEWING MACHINES Dave Fischbein, Minneapolis, Minn., assignorto Dave Fischbein Co., Minneapolis, Minn., a corporation of Minnesota Application August 15, 1955, Serial No. 528,486

1 Claim. (Cl. 112-235) My present invention relates to improvements in sewing machines and more particularly to the presser foot thereof which, acting in conjunction with the needle, throat plate and feed dog of the sewing mechanism, operates to hold the chain in proper position.

It may be well to state here that this present invention is in the nature of an improvement in the presser foot member such as is disclosed in United States Letters Patent No. 2,484,495 issued to me as patentee and assigned to the Dave Fischbein 00.

When sewing articles, especially filled bags, a thick seam or excess of material is frequently encountered at the beginning of the sewing operation, over which the presser foot must travel. I have found that with the present day sewing machines the presser foot does not always remain in contact with the throat plate when commencing the sewing operation, if the material is excessively thick or heavily seamed. As a result, the commencing stitch on the material and the last stitch of the chain may be malformed, such as being loose or entirely skipped. V I

With the above in mind it'is an object of my invention (0 provide a presser foot which rides over a seam or excess thickness of material that will be in contact with the throat plate when engaging material at the beginning f the sewing operation. It is also an object of my invention to provide a presser foot which allows greater tilting or pivoting movement of the same thus cutting down very materially, the amount of upward travel of the presser foot which permits more positive and efficient chaining, and the use of heavier materials with a given machine. It is an additional object of my invention to provide a presser foot that does not ride high at certain points as the same passes over a seam of material.

I shall not here attempt to set forth and indicate all of the various objects of my invention, but other objects and advantages will be referred to herein or else will become apparent from that which follows.

The invention will appear more clearly from the following detailed description when taken in connection with the accompanying drawings, showing by way of example a preferred embodiment of the inventive concept wherein like numerals are employed to designate like parts throughout the several views.

In the drawings forming a part of this application:

Fig. 1 is a view partly in plan and partly in section of the lower part of a sewing machine showing the presser foot, feed dog, throat plate, and etc. with the presser foot shown in tilted position in broken lines.

Fig. 2 is a side elevation of the improved presser foot removed from the machine with the presser foot bar shown by means of dotted lines.

Fig. 3 is a rear elevation of my improved presser foot shown in Fig. 2 partly in section.

Fig. 4 is a top plan view thereof.

Fig. 5 is a bottom plan view thereof.

Fig. 6 is a top plan view of the throat plate.

FICE

Fig. 7 is a sectional view taken on the line 7-7 of Fig. 3.

Referring to the drawings in detail, my presser foot A is mounted directly above the throat plate member 10 and will exert pressure on the said throat plate 10 so that the material or chain is firmly held in place. The throat plate 10 is mounted on and secured to the casing or throat portion 11. The casing portion 11 encloses a feed bar (not shown in the drawings) but which actuates the feed dog 12 which operates in the slots 13 and 14 of the throat plate 10 to eflfect travel of the machine over the material traveling under the foot A and upon the feed dog 12. The slot 13 is formed with the enlarged portion 13' hereinafter referred to.

Also provided is the reciprocal needle bar 15 mounted in the bearing 16 which is secured in the housing portion 17. The needle 18 is mounted in the needle bar 15. The housing portion 17 also mounts the bearing 19 in which is mounted the slidable presser foot bar 20. The presser foot bar 20 is mounted for endwise sliding movement in the bearing 19 and the spring adjusting nut 21. An arm 22 connected to the presser foot bar 20 extends outwardly through a slot 23 in the wall member 24. A coiled spring 25 encircling the presser foot bar 20 is compressed between the adjusting nut 21 and the arm 22. The spring 25 is under compression to hold the presser foot A in cooperating relation with the feed dog 12. A hand lever 26, only a portion of which is shown, is provided for operating the presser foot bar 20 to retract the presser foot A and permits the sides of a bag or other material to be placed for sewing between the feed dog 12 and the presser foot A.

v The presser foot A comprises a centrally disposed base portion 27 which has formed on the front thereof the angularly disposed and upwardly extending toe portion 28. The central base portion 27 has formed therethrough, the needle hole 29 through which the needle 18 passes. The presser foot A is also formed with the spaced apart support members 30 and 31 which are secured substantially to the base portion 27.

I further provide the connecting member 32 which is formed of the upright portion 33 and the forward portion 34 integral therewith. The upright portion 33 is formed with the socket 35 in which the lower end portion of the presser foot bar 20 is positioned and is secured therein by means of the set screw 36. The presser foot A is pivotally mounted on the connecting member 32 by means of the pin 37 which extends through the forward portions of the support members 30 and 31 and through the forward portion 34 of the member 32. The pin 37 is so positioned that the bottom surface of the connecting member 32 is spaced from the upper surface of the base portion 27 as at 37 to allow additional pivoting of the toe 28 of the presser foot A downwardly, and the heel 38 upwardly as the presser foot A leaves the seam of the material being sewed. In addition, the pin member 37 is off-set from the longitudinal axis of the presser foot bar 20 to provide better pivoting of the presser foot A.

The heel portion of the presser foot A has formed on the underside thereof the angularly and longitudinally disposed and spaced kerfs 39, 40, and 41 forming edge and an intermediate notch which allow the intermediate heel portions 42 and 43 formed thereby, to pivot or rock downwardly into the openings 14 and 13' respectively as partly illustrated in Fig. 1. The kerfs 39, 40 and 41 result in the formation of angular surfaces at 39, 40' and 41' respectively. This pivoting or rocking of the presser foot A is actually done on the points 44, 45 and 46 formed by the kerfs 39, 40 and 41 respectively with the points 44, 45 and 46 resting on the portion 47, 48 and 49 respectively of the plate 10 approximately at the positions numbered 50, 51 and 52 respectively. To

further clarify the downward rocking or tilting movement of the heel portion 38 of the presser foot A, it is apparent that the intermediate portion 42 rocks or tilts downwardly into the opening 14 of the plate while the intermediate under portion 43 rocks or tilts downwardly into the opening 13 at the enlarged portion 13' thereof. It is apparent that the rocking or tilting of the heel 38 is implemented by the pivot pin 37. It is to be further noted that the angular surfaces 39', 40 and 41' contact the flat portion 47, 48 and 49 respectively, of the plate 10 when the heel 38 is tilted downwardly to the position shown by broken lines in Fig. 1.

The throat plate 10 is formed with the aperture 53 through which the needle 18 passes having come down through the needle hole 29 of the presser foot A. It is well to note here that it is highly important that intimate contact be maintained between the base portion of the presser foot 27 and that portion of the throat plate 10 immediately rearwardly of the aperture 53 known as the chaining apron 53'.

In the operation of my device for example, in sewing or closing the top of a bag, the top edges of the sides of the bag are inserted under the toe portion 28 of the presser foot A and the machine started. The machine illustrated is of the portable type and is moved automatically across the open top of the bag. When the lower end portion of the toe portion 28 encounters a scam in the bag material, the toe 28 of the presser foot A is tilted upwardly as illustrated in Fig. 1 by means of broken lines. At same time, the intermediate portions 42 and 43 of the heel portion 38 tilt or drop downwardly into the slot portions 14 and 13' respectively as illustrated in part in Fig. 1. Also at the same time the entire presser foot A tends to rise to some degree against the action of the-spring 25 due to the start of the passage of the seam under the presser foot A. However, the rise or upward travel of the presser foot A is less than heretofore known due to the fact that the intermediate portions 42 and 43 of the base 27 rock down into the slots 14 and 13' respec tively thereby producing positive and effective chaining of the thread (not shown) through the bag material.

As the presser foot A begins to leave the thickened seam portion, the toe portion thereof can tilt downwardly, slightly, due to the pivoting at 37 and the fact that the base portion 27 can rise into the space provided at 37' until it contacts the underside of the connecting member 32. As the presser foot A of the machine leaves the thickened seam portion, the presser foot A then assumes the horizontal position shown in Figure l by means of full lines.

I have thus provided a presser foot having greater pivoting or rocking movement than heretofore attained thereby creating a minimum of upward travel of the presser foot from the feed dog 12 with the result that a more perfect chain is made at points where seams or undue material thickness is encountered and also permits the stitching of heavier materials effectively.

The invention is not to be understood as restricted to the details set forth herein since these may be modified within the scope of the appended claim without departing from the spirit and scope of the invention.

What I claim is:

In an electric sewing machine, a presser foot, and a cooperating throat plate including spaced slots therethrough, said presser foot having longitudinal edges, an upturned toe section, a central section, and a heel section, said presser foot sections as an entirety, having a fiat, smooth, work engaging undersurface, a notch formed in each longitudinal edge and intermediately of the heel section, a longitudinally extending kerf'formed in the heel section of the presser foot adjacent each one of the said notches, the end-wall portions of the notches and the kerfs being inclined downwardly and forwardly relative to the plane of the working surface of the said central and heel sections of the presser foot to afiord rocker means to impart downward rocking tilting movement of the heel section of the presser foot at said notches when in engagement'with the walls of an aligned slot in the throat plate, and means pivotally connecting the presser foot to the presser footbar of a sewing machine.

References Cited in the file of this patent UNITED STATES PATENTS 381,090 Sutherland Apr. 10, 1883 446,575 Woodward Feb. 17, 1891 2,318,843 Enos May 11, 1943 2,494,790 Zahler Jan. 17, 1950

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