US1922966A - Overedge stitch forming mechanism - Google Patents

Description

Aug. 15, I

OVEREDGE STITCH FORMING MECHANISM Filed Dec. 9, 1929 3 Sheets-Sheet 1 Aug. 15, F T 1,922,966

OVEREDGE STITCH FORMING MECHANISM Filed Dec. 9, 1929 3 Sheets-Sheet 2 Aug. 15, 1933- T 1,922,966

OVEREDGE STITCH FORMING MECHANISM Filed Dec. 9, 1929 3 Sheets-Sheet 3 nism for sewing machines for forming overedge the looper thread 1001? a d presents its Own 1 1 Patented Aug. 15, 19333 UNITED STATES PATENT OFFICE.

1,922,968 OVEREDGE STITCH FORMlNG MECHANISM Friedrich Lutz, Stuttgart, Germany, assignor to Union Special Machinenfabrik, G. in. b. H., Stuttgart, Germany Application December 9, 192.9,Serial No. 412,792,

and in Germany January 9, 1929 -1 Claim. (01. 112-462) The invention relates to new and useful imported so that it may be shifted for varying the provements in stitch forming mechanisms for oscillating position of the overedge looper. The sewing machines, and more particularly to an bracket has its supporting base curved about an overedge stitch forming mechanism. axial line and the machine frame is provided with It is Well known that in an overedge stitch a similarly curved supporting seat for the forming mechanism including a needle. a looper bracket. beneath the work support and a looper operating Suitable bolts are provided for holding the. over the edge of the work support that said overbracket in various set positions. The curvature edge looper should move in rear of the under of this supporting face of the bracket is such looper and in front of the needle in order to that. when the working position of the looper is make a proper stitch formation. It is also well shifted, the plane of oscillation of the looper will known that in order to avoid the skipping of be changed so as to produce a greater or less stitches the looper should work close to the neeangle with the plane of the work support and dle as it passes the same. thus it is that the looper when shifted can be An object of the present invention is to proset so as to pass properly in rear of the lower vide a supporting means for the overedge looper looper and also pass properly in front of the whereby the working position of the looper may needle. i be shifted so as to properly position the looper When the needle is changed from a smaller for needles of different diameters. to a larger needle, then the looper bracket is In the drawings which show by way of i1lusshifted so that the overedge looper will clear the tration one embodiment of the invention: needle when above the work support and at the Figure l is a view from the front of the machine same time move close to the needle so as to showing the improved supporting means for the insure proper stitch formation. v e ooper. The invention will best be understood by a Fig. 2 is a View showing the supporting means more detailed reference to the drawings wherefor the overedge looper in side elevation and also in the overedge looper is indicated at 1. This showing the position of the under looper. overedge looper is mounted on a carrier 2 which Fig. 3 is a plan view of a part of a sewing mais attached to a shaft 3 and the shaft 3 is mounted chine showing the means for supporting the overfor oscillation in a bracket 4. A link 5 is conedge looper. nected to an arm projecting from a sleeve at- Fig. 4 is a view showing more or less diagramtached to the shaft and thus it is that the shaft matically the needle, the needle path and the is oscillated and the overedge looper moved from plane in which the overedge looper oscillates. a position beneath the plane Of the W up- Fig. 5 is a view similar to Fig. 4, but showing port to a position over the plane of the work supthe overedge looper shifted so as to change the Do e needle is indicated at 6 in the draW- inclination of its path of oscillation for a different ings. The un o p is indicated at 21 n the size needle. drawings. This under looper is preferably of a Fig. 6 is a view in perspective showing more thread carrying type and moves into the needle or less diagrammatically the needle, the under t ad 1001) beneath e w upp a d' a looper, and the overedge looper at the extremes p n Wh e h v r s l p r engages said of its movement, and the 10 9331 d curvalooper thread and carries the same above the ture of the bracket supporting th overedge work support so that it is positioned for the needle looper. to enter the same. If the overedge looper is of The invention is directed to a stitching mechaa thread carrying t p n of u i nt rs stitches, which includes a reciprocating needle, fill the needle entelfi This yp 0f V d an under thread carrying loo er, d an Overstitch forming mechanism is well known in the edge looper. The overedge looper is mou t d t art. The feeding mechanism is not shown in the oscillate about a fixed axis which is so disposed dalwirlgsi but the 11R3 of feed intelsecfis the that the looper moves in a plane inclined to the needle P Substantially at the point 16, and is work support and passes from a position in rear in a dir-pctioil at right angles the plane of Q of the under looper beneath the cloth plate to per or directly aw VfIOm the Observer, in a position in front of the needle above the cloth Figures 1 and plate. The shaft supporting the upper looper The present invention is directed particularly 110 is mounted in a bracket which is in turn suptothe way in which the bracketsupporting the overedge looper is mounted whereby the oscillating position of the looper may be changed at will.

The supporting bracket 4 for the looper is provided with a curved cylindrical face 8. The

frame 13 of the machine is provided with a simline of the shaft 3 carrying the overedge looper 1 at 11. The overedge looper 1 moves from a. point 19 beneath the work support to a point 18 above the work support. The path of movement of the looper is indicated by line 15, Fig. 6. The axial line 16 of the cylindrical faces 8 and 9 also intersects the path of movement of the looper at the point 17. The axis of the looper shaft is inclined to the axial line 16, as has already been noted.

When the bracket 4 is shifted, it isshifted about the axial line 16, and inasmuchas this line intersects the path of oscillation of the overedge looper midway as indicated at 1 between the extremes of movement of the looper, this point remains substantially the same for various set set so as to. move in the path indicated at 1a-1a for a given size of needle 6. When it is desired to use a larger needle as indicated at '7 in Fig.

5, then the bracket is shifted, and when the bracket is shifted, the plane of oscillation of the looper is charged so that the looper moves to a greater extent in rear of the under looper and a greater extent in front of the needle, as clearly shown in Fig. 5. The looper will, however, always pass through the point 1'? regardless of the set position of the bracket 4.

A loop holder is indicated at 20 in the drawings. This loop holder is in line with the axis of the'shaft supporting the overedge looper and mounted on the bracket 4 so that when the bracket 4 is shifted this loop holder will also be shifted. I V a From the above it will be apparent that a sup port for the overedge looper has been provided which when shifted changes the angle of the plane of oscillation of the looper relative to the work support and thereby the overedge looper may be caused to move at different distances from the center of the needle path without interfering with its proper cooperation with the under looper.

Having fully described my invention, what I claim as new and desire to secure by Letters Patent, is:-

In an overedge stitch forming mechanism, the combination of a needle, an under looper. an overed'ge looper, a shaft on which said over edge looper" is mounted for oscillation, a

bracket for supporting said shaft, said shaft being disposed so that the looper moves in a path passing in rear of the under looper and in front of the needle, and a frame member for justably supporting said bracket, said bracket and frame member having their contacting faces curved about an axial line passing through the axial line ofoscillation of the overedge looper and a joint in the path of movement of the loop er midway between the extremes of movement of said overedge looper.

- FRIEDRICH LUTZ.

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