US2103470A - Presser mechanism for sewing machines - Google Patents

Description

Dec. 28, 1937. F, A KUCERA 2,103,470

PRESSER MECHANISM FOR SEWING MACHINES Filed Jan. 50, 1936 INVENTOR- Frank fl immra/ Patented Dec. .28, 1937 ATNT oFric E PRESSER MECHANISM FOR SEWING MACHINES Frank A. Kucera, Chicago, 111., assignor to Union Special Machine Company, Chicago, lit, a corporation of Illinois Application January 30, 1936, Serial No. 61,469

2 Claims.

This invention relates to presser mechanism of the type in which a vertical bar carrying the presser foot is confined to axial up and down movement in a guide head at the end of an over- 6 hanging arm of the sewing machine and yieldingly urged downward by a horizontal leaf spring.

In such mechanism, as heretofore constructed, the end of the leaf spring bore either directly on the top end of the presser bar, or upon a collar or other fixed projection on said bar, with the result that it exerted lateral strains which tended to cause binding and sticking of said bar in the guide head.

The purpose of my invention is to obviate the difficulty to which attention has just been directed. This objective I attain in practice, as hereinafter more fully disclosed, through provision of a connecting means between the leaf spring and the presser bar capable of compensatgo ing for lengthening and shortening of said spring incident to flexing thereof so that lateral straining and binding of said bar is effectively precluded and the latter left entirely free to efiiciently perform. its allotted functions.

In the attached drawing, Fig. I is a side elevation of a sewing machine conveniently embodying my improved presser mechanism.

Fig. II is a fragmentary detail plan view looking as indicated by the arrows II--II in Fig. I and drawn to a larger scale.

Fig. III is a fragmentary detail sectional view taken as indicated by the arrows III-III in Figs. I and II; and

Fig. IV is a perspective View of the connecting member hereinbefore mentioned.

The illustrated sewing machine has a hollow overhanging arm I which extends horizontally from an integrally-formed hollow standard 2 rising from one end of a base 3, the top surface of the latter being flat and constituting a work support. Confined to axial movement in a guide head 4 at the free end of the arm I is a bar 5, which, at its lower end, carries a pair of needles 6 that cooperate with a looper or loopers (not shown) concealed within the hollow of the base 3. Through suitable connections likewise within the framework of the machine the needles 6 and the concealed looper or loopers are caused to function in timed relation in forming chain stitches after a well known manner.

Also having guidance for axial movement in the head 4 is a vertical presser bar I to the bottom end of which is secured the presser foot 8 whereby the fabric being sewed is. held down against the top surface of the base 3 while being progressively advanced by the feed mechanism (not illustrated) of the machine. The presser bar l is subject to a horizontal leaf spring H] which is mounted on the top of the arm I, and whereof the inner or right hand end is apertured to en- 5 gage a fixed upstanding anchorage stud projection H within the recess i2 of a movable cap l3 closing an opening through which access is had into the hollow of the standard 2. The force of the spring it is regulatable by means of a thumb nut i i threaded on a vertical stem on the arm I which passes through a central aperture in said spring. Interposed between the thumb nut i4 and the top of the spring i9 is a smaller auxiliary leaf spring l6.

In order to prevent the imposition of binding strains upon the presser bar 1 and so preclude interference with the free operation thereof, I have made the provisions which are about to be described.

From Figs. I and III, it will be observed that the presser bar 7 is formed with a diametrically reduced top portion i1 whereof the end is rounded and over which is placed a stirrup-like member I 8 having an outwardly projecting circular flange it at its bottom. As shown at 2% in Fig. III, the stirrup-like member l8 has an internal spherical recess centrally of its top engaging the rounded upper end of the presser bar I, and as further shown, said member has an axial opening 2! of a diameter considerably larger than that of the reduced portion I! of said presser bar. The flange is of the stirrup-like member it constitutes a bearing surface for the outer end of the leaf spring H] which is clevised or bifurcated in accordance with my invention as shown at 22 in Figs. II and III to clear the upper portion of said member l8.

By virtue of the capacity for universal pivotal movement of the stirrup'member I8 about the upper rounded end of the presser bar i lengthening and shortening of the leaf spring iii incident to its flexing in accommodating the movements of the presser bar 1 is compensated for. Accordingly, no lateral strains will be induced in the presser bar 1, the latter being thereby insured against binding within the guide head 4 and left free to move up and down as difierent thicknesses of fabric vpass beneath the presser foot 8.

Having thus described my invention, I claim: 50

1. Presser mechanism for sewing machines and the like including a presser bar with a rounded end; a guide confining the bar to axial movement; a stirrup-like member engaged over and supported, with capacity for universal pivotal 55 movement, on the rounded end of the presser bar; and a leaf spring exerting endwise pressure upon the bar, said spring having its end bifurcated to straddle the stirrup member and bear upon a flange around the bottom of the latter.

2. Presser mechanism for sewing machines and the like including a vertical presser bar; a guide confining the presser bar to axial movement; a leaf spring for exerting endwise pressure on the bar; and a suspension member having a universal pivot bearing with the top end of the bar and affording a rest for the free end of the spring 5 below said pivot bearing.

FRANK A. KUCERA.

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