US19141A - Improvement in sewing-machines - Google Patents

Description

D. HARRIS.

Sewing Machine.

Patented Jan. 19. 1858.

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v UNITED STATES PATENT O FICE.

DANIEL HARRIS, OF BOSTON, MASSACHUSETTS.

IMPROVEMENT IN SEWING-MACHINES.

Specification forming part of Letters Patent No. 19,14], dated January 19, 1858.

To aJZ whom it may concern Be it known that I, DANIEL HARRIS, of Boston, in the county of Suffolk and State of Massachusetts, have invented an Improvement'in Producing Tension or Friction upon the Thread in a Sewing-Machine, the nature and operation of which I hereby declare to be fully set forth in the following specification, reference beinghad to the accompanying drawings, to which this specification and letters refer.

The invention consists in an improved manner of regulating the delivery of the thread from the spool or other source to the needle by atension-clamp located at any convenient intermediate point.

Figure 1 of the drawings represents a side elevation of the tension-clamp as applied upon goose-neck, where I generally prefer to place it. Fig. 2 is a vertical section of the clamp, and Fig. 3 ahorizontal section. of it.

A in the drawings denotes a screw pin or spindle applied on top of the gooseneck, or located in any other convenient place.

B is a piece of rubber or gum-elastic tubing placed on the spindle and resting upon a plate or base, 0, or directly upon the goose-neck or plate to which the spindle may be applied, Upon the top of this tubing a washer, D, made large enough in diameter to cover or nearly cover the tubing B, is placed, as seen in Figs. 1 and 2. This washer I generally prefer, for wear, to make of parchment, as this is tough and yielding, while it is smooth and somewhat oily, and permits the thread to run easily when pressed against it. It may, however, be made of any smooth, dry, and somewhat yielding material that will keep properly in place, wear well, and prevent the rubber from touching the thread. Over this disk, and through an aperture, a, in the spindle, the threadF passes, a parchment disk, G, covered by a rubber or gum-elastic tube, H, being placed over the thread, as seen in Fig. 2. On top of the spindle a screw cap or nut, I, is fixed, the requisite pressure being produced upon the thread by rotation of this nut, said pressurebeing upon the length of thread between the disks.

In sewing with thread fed directly to the needle from a common spool the thread is delivered too fast, being all taken from the spool at each stitch,when, in order tomake the stitching tight, it should be partially taken from the slack of the previous loops or stitches. To remedy this the thread is generally rewound from the common spool onto a large bobbin, r

' use. In sewing the chain-stitch much depends upon the tightness with which the stitches are drawn into the cloth, as when the sewing is loose it easily unravels. Unless the looper 0r beak has a strong spring thrown forward in taking each loop, so as to take up the slack of the preceding loop, the tension must be continually varied in order to produce the proper draw upon this next preceding loop or stitch. This spring-throw is very apt to break the thread. WVhen the stitches are very long, all or nearly all of the thread taken-from the spool by the stitch but as the stitch is shortened so much needle in its descent is required to form the thread is not needed,while the needle in its de-' scent takes the same length from the spool. This leaves the stitch loose, and to overcome this the needle at its next descent shoves down part of its thread from this previous slack, and

to make it do so such variablepressure must be applied to the thread back of the needle in the different stitches as to cause the needle to take its thread from previous slack, instead of from the spool, until .the stitch is properly drawn in, when it will take the rest from the spool. To do this without producing a j erk upon the thread suffioient to break it, as is often the case where the looper has a spring-' throw given to it, the thread for this purpose is passed between the two rubber springs or tubes, contact with the rubber to unduly bind the thread being prevented by the intervention of the smooth and yielding disks, the pressure being varied according to the stitch by the screw-cap.

I claim- The specific device herein described for applying tension to the thread during its pasdegree of intensity required, .substantially as sage from the bobbin or spool to the needle set forth. that is, causing it to run through the eye of Intestimony whereof I have hereto set my the spindle and between two disks of parehsignature this 26th day'of June, A. D. 1857.

ment when said disks are placed upon the DANL. HARRIS.

spindle betweentwo india-rubber tubes or cyllVitnesses: J

inders, which are liable to be compressed in N. A. DYER,

the direction of the axis of the spindle to any FRANCIS GOULD. v

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