US621980A - Tension-releasing mechanism for sewing-machines - Google Patents

Description

No. 62I,980. Patented Mar. 28, I899. F. I. STOCKWELL.

TENSION RELEASING MECHANISM FOR SEWING MACHINES.

(Application filed Mar. 15, 1898.)

(No Model.)

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FRED I. STOCKWELL, OF MALONE, NEW YORK.

SPECIFICATION forming part of Letters Patent No. 621,980, dated March 28, 1899.

Application filed March 15, 1898.

To whom it may concern:

Be it known that I, FRED I. S'rooKwELL, a citizen of the United States, residing at Malone, county of Franklin, and State of New York, have invented a certain new and useful Improvement in Automatic Releases for Thread-Tensions for Sewing-Machines, of which the following is a specification.

My invention relates to a new and useful improvement in automatic releases for threadtensions for sewing-machines, and has for its object to provide a simple and effective means whereby the tension upon the upper thread may be relieved automatically when the presser-foot is lifted for the shifting of the work from one point to another, thus avoidin g the necessity of having to release the tension by'hand or draw the thread against the tension, which requires considerable strain upon the thread, as well as deflects the needle, occasioning annoyance and" loss of time.

With these ends in view this invention consists in the details of construction and combination of elements hereinafter set forth and then specifically designated by the claims.

In order that those skilled in the art to which this invention appertains may understand how to make and use the same, the construction and operation will now be described in detail, referring to the accompanying drawings, forming a part of this specification, in which Figure 1 is a rear elevation of a sewingma'chine of standard make having my improvement applied thereto, the same being connected with the treadle or knee presserfoot lift mechanism; Fig. 2, an enlarged sec-- tion of the tension, showing the same released by the pivoted lower plate, the arm for operating this plate being shown in dotted lines; Fig. 3, a plan view of the tension with my improvement applied thereto; and Fig. 4, a section at the line m as of Fig. 1, showing the connection between the lever for operating the presser-foot and the arm for operating the tension.

In carrying out my invention as here embodied I form with or secure to the pivoted tension-plate A an extension or arm B, which after projecting outward from the plate, as indicated at 0, runs parallel with the machine-head and terminates in a flanged sec- Serial No. 673,943. (No model.)

tion D, forming a groove for the reception of the stud, as clearly shown in Fig. 4. The lever H is pivoted at J to the head of the machine and is connected by the rod K to a suitable foot or knee treadle, whereby this lever may be operated without occupying the hands of the operator, as is well understood. The opposite end of the lever H is connected by a link L to the presser-foot bar M by the screw 0, passing through the slot P, thus when the treadle is operated the presser-foot is raised fromthe work, thereby freeing the latter, so that it may be moved from point to point as occasion may require, and when the presser is thus raised it is obvious that the post E will force the arm B upward, and in so doing swing the tensionplate A in such manner as to deflect the plate Q and free the thread R, as clearly shown in Fig. 2. When the presser-foot and tension mechanism are in this position, it will be seen that the upper thread maybe as readily drawn from the-spool as the lower thread from the shuttle, thus avoiding the deflecting of the needle or the chafing of the upper thread in passing through the eye thereof under tension.

It is to be noted that the slot P provides for the ordinary movements of the presserbar without affecting the link or lever H, so that the presser-foot may pass over work of varying thicknesses without in any wise affecting the tension, and this is of considerable importance, since should there be a rigid connection between the tension and the presser foot or bar when said presser-foot is lifted to a considerable extent by quick ,work the tension would be released, and, as is well known, the tension is most needed when thick work is being operated upon.

A further feature of my invention which is of considerable importance is the fact that thereis no rigid connection between the post E and the arm 13, as the latter simply rests upon the former, and therefore when it is necessary to release the tension by hand independent of the treadle this may be accomplished by forcing the arm upward.

One of the great advantages of my improvcment is the fact that it may be attached to any standard machine, requiring no alteration thereof, thus adapting it to machines of any use, and it is especially advantageous for use in connection with machines which are operating upon certain classes of worksuch as buttonholes, stitching on of buttons, binding, two-needle cylinder-machines, and tacking-machines, as in these classes of work the operator is constantly having to stop the Work at a given point and shift it to another point, and in so doing thread must be drawn through the needle with tension or released by hand, whereas by my improvement the same is accomplished automatically when the presser-foot is lifted.

Of course I do not Wish to be limited to the exact details of construction here shown, as these may be varied to a certain extent with out departing from the spirit of my invention.

Having thus fully described my invention, What I claim as new and useful is 1. In combination with a presser-foot of a sewing-machine, a lift-lever for operating the presser-foot, a post carried by the lever, a plate 2, a tension-plate having an arm whereby it is operated, said arm having a flanged section fitting over the post and means for operating the lifting-lever, as and for the purpose described.

2. In combination, a presser-foot, a lever, a link connecting the lever and presser-foot, a post carried by the lever, a plate 2, a tension-plate, an arm formed with the tensionplate having a flange embracing the post, said post being adjustable on the lever, as and for the purpose described.

In testimony whereof I have hereunto affixed my signature in the presence of two subscribing witnesses.

FRED I. STOCIUVELL.

Witnesses:

J. B. TWADDLE, JOHN LAW.

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