US2697994A - Attachment for sewing machines - Google Patents

Description

D66. 28, 1954 c H, WURKER 2,697,994

ATTACHMENT FOR SEWING MACHINES Filed Feb. 26, 1952 INVEAII'OR: (4R1 Hf/Nd lm'wm United States Patent ATTACHMENT FOR SEWING MACHINES Carl Heinz Wiirker, Aistaig am Neckar, Germany Application February 26, 1952, Serial No. 273,4ss

. Claims priority, application Germany March 5, 1951 3 Claims (Cl. 112-460) The present invention relates to an attachment of a kind tobe mounted on conventional sewing machines, such as the familiar domestic types, and permits making zigzag seams, button hole stitches and the like on such machines.

The invention relates. more specifically to such attach merits which are equipped with a lever essentially oscillating in a horizontal plane, the free end of said lever carrying a small plate, called the presser foot. This plate is tightly pressed down on the material being sewn and resting on the throat plate and, in response to the motion of the said lever, the presser foot transmits to the material being sewn areciprocating motion transversely to the direction in which the material travels. In order to make this possible the underside of the presser foot is provided with frictional means such as. sharp-edged ribs extending in the direction in which the material travels and being pressed into the cloth during the sewing operation.

As is Well known, when making a button hole stitch, a

narrow, thick ridge or welt is formed, which is especially marked when the edge is reinforced by an additional thread. As soon. as this ridge, as sewing goes on, arrives underneath one of the presser feet hitherto used, the presser foot is unable to grip the material properly because the thick ridge prevents the frictional ribs from being lowered onto the material. The presser feet hitherto used then cease to transmit a reciprocating motion to the material being sewn, which makes it impossible to produce the desired zigzag seam.

It is the object of the invention to avoid this drawback and to provide dependable means for zigzag sewing when makig button hole stitches.

It is an essential characteristic of the invention that, in addition to the well-known ribs, the underside of the presser foot designed for-making button hole stitches is provided with longitudinal grooves extending in the direction in which the material travels and serving to take up the thick marginal ridge being formed during the sewing operation. As a result of this provision the thick 7 ridge at the button hole edge can be taken up by the grooves in such a manner that the frictional means on the underside of the presser foot are now able to place themselves tightly on the material being sewn, to grip it securely, and to transmit to it a reciprocating motion transversely to the direction in which the material travels.

This and the other features of the invention will be clearly understood from the following description of a preferred form of the invention illustrated in the accompanying drawing, in which Fig. 1 is a fragmentary sectional view of an attachment for sewing zigzag seams;

Fig. 2 is a top view of a presser foot in accordance with the present invention;

Fig. 3 is a vertical section taken along the line 3-3 of Fig. 2;

Fig. 4 is a bottom view of the same presser foot;

Fig. 5 is a vertical section on an enlarged scale taken along the line 55 of Fig. 2; and

Fig. 6 is another vertical section on an enlarged scale taken along the line 6--6 of Fig. 2.

The mechanism shown in Fig. 1 comprises a base plate 10 which can be fastened (e. g. clamped) by means of a block 11 to the presser bar 12 of a sewing machine. The base plate 10 carries a housing 13, Whose side walls support the drive mechanism which transforms the vertical motion of the needle bar 14 into a reciprocating motion of a lever 15 in an essentially horizontal plane. As this drive mechanism is well known and does not constitute a part 2 of the invention, it need not be describedin detail. The free forward end 16 of the oscillating lever 15 carries the material'displacing foot or presser foot 17, with the aid of which the material, which is placed above the throat plate, is given a reciprocating motion transversely to the linear direction of material travel produced by the feeding mechanism of the sewing machine. In this manner a seam achieved.

The presser foot 17 is equipped with two laterally bentup extensions 18 in which holes 19 to receive a pin 20 are provided.- The pin 20 is inserted into the holes 19 and into the corresponding holcs in the} forked forward end 16 of oscillating lever 15 with the purpose of fastening the presser foot 17 to the oscillating lever. Furthermore, the presser foot 17 has a stitch hole 21 serving as a passage for needle 22 which is secured to the needle bar .14- of the sewing machine. It is a special feature of the invention that at least the front edge 23 of the hole 21, i. e. the edge on the operators side, is so bevelled that said hole 21 forms a funnel with the large diameter on top, thus giving the operator an unobstructed vision of the seam as it is conveyed along (Figs. 2 and 3). it is also of advantage to bevel the lateral edges of hole 21 in the same manner, as is shown in Fig. 2, relative to the left-hand edge 24.

On its underside the presser foot 17 is provided with the well-known sharp-edged ribs 25 which are pressed into the material being sewn, thus producing a friction which serves to force the cloth to take part in the reciprocating motion of the presser foot 1'7. The essential feature of the invention is, that aside from these wellknown longitudinal ribs 25, the longitudinal grooves 27 and 28 are provided, which grooves are so deep that they can take up the thick ridge produced when making a button hole stitch.

Groove 27 runs from the front edge 29 of the presser foot 17 into the stitch hole 21, and is so broad and deep that it can take up an already completed ridge of a. button hole edge. In the top of the groove 27 is a slot 31 reaching up to the stitch hole 21 (see Fig. 6) and serving to place the end of the thread which protrudes from the needle 22 under the presser foot 17.

The groove 28 runs from the stitch hole 21 to the rear edge -32 of the presser foot 17. its left-hand edge is arranged in straight alignment with the left-hand edge of groove 27. The groove 28 is so broad that it is capable of taking up two button hole edge ridges lying alongside each other.

Another groove 26 runs parallel to the narrow groove 27 from the front edge 29 of the presser foot 17 into hole 21 and serves for inserting a reinforcing thread which is to surround the button hole and to be sewn into the button hole stitch. A hole 30 is provided in presser foot 17 for inserting such a reinforcing thread, said hole being preferably arranged in inclined position and reaching down into groove 26 (Fig. 3). Owing to this slanting hole 30 and groove 26 the reinforcing thread can be advanced to the stitch hole 21.

It is another feature of the present invention that narrow, smooth strips 33 are arranged on both sides of the grooves 26, 27 and 28. These strips serve to hold down and smooth the cloth along the seam during the sewing operation.

Handling and mode of operation of the attachment according to the invention are as follows:

When a button hole is to be made, the presser bar 12 must be lifted, and the material to be sewn must then be so placed under the presser foot 17 that the starting-point of the button hole stitch-is within the stitch hole 21 below the needle 22. The presser foot 17 is then lowered by means of the presser bar 12 and must be placed tightly on the material. If the button hole edge is to be reinforced by an additional thread, the latter must be inserted through the slanting hole 30 into the groove 26 and placed on the material being sewn in such a manner that its forward end extends somewhat beyond the stitch hole 21. After the feeding mechanism of the sewing machine has been set to a slow material travel, and after the drive mechanism of the oscillating lever 15 has been set to a small deflection transversely to the direction in which the material travels, sewing may commence. The button hole edge which is guided during the sewing operation along the right-hand edge of the broad groove 28 must be completed first. After completion of the first edge, the presser foot 17 must be raised by means of the presser bar 12, and the material must be turned around through 180, whereby it is of advantage that the needle 22 is left in the material being sewn. By lowering presser foot 17 again onto the material, the completed edge or welt enters the groove 27, and consequently it cannot prevent the ribs 25 from tightly gripping the cloth and moving it along, when the oscillating lever 15 transmits to the presser foot 17 a reciproeating motion transversely to the direction in which the material travels. Similarly, because the groove 27 permits free passage of the welt therethrough, smooth portions 33 can contact the cloth adjacent the welt for holding it down. Before proceeding to sew the second edge, the oscillating lever 15 must be adjusted to a large lateral deflection with which several stitches must be made so as to form the transverse bar at one end of the button hole. The oscillating lever 15 must then be set back to its small lateral deflection so that the second edge can be completed. During this sewing operation the material is fed accurately parallel to the first ridge because said first ridge is taken up by groove 27 and thus positively moved in a straight line. After passing the stitch hole 21, the first ridge enters the broad longitudinal groove 28 and moves along the left-hand edge of the said groove which, as previously mentioned, is in straight alignment with the left-hand edge of the narrow groove 27. Thus, the second ridge will be made accurately parallel to the first ridge and the proper distance between the two button hole edges will be correct, said distance being determined by the distance between the two grooves 26 and 27. Upon completion of the second ridge the second transverse bar at the end of the button hole is made in the same manner as the first transverse bar, as described above. The attachment according to the invention thus enables an operator to make simple and accurate button hole stitches on a sewing machine of the familiar domestic type.

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

1. In a zig-zag stitching attachment for sewing machines with a vertically reciprocable needle bar and with means for reciprocating the material to be stitched in a substantially horizontal plane transversely of the line of feed of said material; a material-displacing foot engageable with said reciprocating means, friction elements disposed on the underside of said foot imparting motion to said material, and at least two grooves disposed on said underside of said foot and extending in a direction substantially parallel to the line of feed of said material,

said grooves being arranged for receiving and linearly guiding relatively thick welts, respectively, defining adjacent edges of a buttonhole and being of suflicient depth to permit free passage of said welts therethrough, said foot being provided with a stitching hole disposed intermediate the front and rear edges of said foot, one of said grooves having spaced lateral walls and extending substantially from said front edge of said foot to said stitching hole, said one groove being dimensioned for the reception of one of the buttonhole welts, the other groove having spaced lateral walls and extending rearwardly from said stitching hole to said rear edge of said foot and having a width substantially twice the width of said one groove for the reception and guidance of both welts of said buttonhole, one of the walls of said one groove being aligned with one of the walls of the other groove.

2. A zig-zag stitching attachment according to claim 1, wherein said foot is provided with a third groove extending substantially from said front edge of said foot to said stitching hole and substantially parallel to said one groove, said third groove communicating with a passageway provided in said foot for insertion of a reinforcing thread.

3. An attachment for sewing machines, comprising a material displacing foot, friction elements disposed on the underside of said foot for contacting material to be sewn, said foot having front and rear edges and being provided with a stitching hole, said foot having on its underside a first groove, a second groove and a third groove, each groove being provided with spaced lateral walls extending in substantially parallel direction to each other, smooth foot portions for holding down the material to be stitched located alongside said grooves, said grooves being arranged for receiving and linearly guiding relatively thick welts defining a buttonhole and being of sulficient depth to permit free passage of one of said welts therethrough, said first groove and said third groove extending substantially from the front edge of said foot to said stitching hole and being dimensioned for the reception of a respective buttonhole welt, said second groove extending from said stitching hole to said rear edge of said foot and being dimensioned for the reception of both welts of said buttonhole, one of the lateral walls of said first groove being aligned with the respective lateral wall of said second groove.

References Cited in the file of this patent FOREIGN PATENTS Number Country Date 487,217 Germany Dec. 4, 1928 636,702 Germany Oct. 13, 1936

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