US336827A - Eoswell h - Google Patents

Description

R. H. ST. JOHN.

TENSION FOR-SEWING MACHINES.

(Nq Model.)

Patented Feb. 23, 1886.

N PETERS. Fhnlo Lllhognphen Washington. D. (:.Y

UNITED STATES PATENT Orrrcn.

ROSWELL H. ST. JOHN, OF TOLEDO, OHIO, ASSIGNOR TO THE UNION MANUFACTURING COMPANY, OF SAME PLACE.

TENSION FOR SEWING-MACHINES.

SPECIFICATION forming part of Letters Patent No. 336,827, dated February 23, 1836.

, Application filed October 16,1884. Serial No. 145,666. (X0 model.)

To all whom itmay concern/.-

Be it known that I, RoswELL H. ST. JOHN, of Toledo, in the county of Lucas, and in the State of Ohio, have invented certain new and useful Improvements in Tensions for Sewing- Machines; and I do hereby declare that the following is a full, clear, and exact description thereof, reference being had to the accompanying drawings, making a part of this specification, in which- Figure 1 is a perspective View of the parts of my improved device separated from each other. Fig. 2 is a like view of the same in place upon a sewing-machine, and Fig. 3 is a side elevation of said device.

Letters of like name and kind refer to like parts in each of the figures.

The object of my invention is to increase the efficiency of the upper-thread tension of a sewing-machine; and to this end said invention consists, principally, in a sewing-machine tension composed of a spring-plate that rests upon and is held with a yielding pressure against a pivoted bearin g, which is adapted to rock in a plane that is parallel with the line of draft, substantially as and for the purpose hereinafter specified.

It consists, further, in a sewing-machine tension composed of a spring-plate which is supported at one end upon a fixed bearing and at its opposite end rests upon and is held with an adjustable pressure against a pivoted rocking bearing, substantially as and for the purpose hereinafter shown.

It consists, further, in a sewing machine tension composed of an adjustable pressureplate superimposed upon a rocking bearing, which, by means substantially as shown, has its motion limited, substantially as and for the purpose hereinafter set forth.

It consists, finally, in the construction and combination of part-s substantially as and for the purpose hereinafter shown and described.

In the annexed drawings, A represents the horizontal portion of the stationary arm of a sewing-machine,from the upper side of which, and forming a part of the same, three bosses, a, a, and a, respectively, extend upward from equidistantpoints. The rear boss, a, has, preferably, a height of about three-fourths of an inch, and is provided Within its upper end with a horizontal groove, (1 The central boss, a, has a height of about one-half an inch, and is provided with a central vertical opening, a, that is threaded, while the third boss, at, has a height of about one-half an inch, and is provided with a horizontal transverse opening, a".

Pivoted upon the boss a is a flat bearing, B, which is preferably constructed from sheet metal, with two opposite downwardly-turned ears, b, that embrace the sides of said boss, and through which and through the opening a passes a pivotal screw, 0. From the rear edge of said bearing an arm, 1), extends rearward and downward, and has its outer end contained within a notch, a, that is formed in the contiguous side of the central boss, a. Said notch has preferably such vertical dimensions as to permit the engaging end of said arm to move about one-sixteenth of an inch in such direction before the motion of said bearing is arrested.

Resting upon the bearing B, and within the groove a of the boss a, is a flat spring-plate, D, that is provided with a central opening, d, through which the threaded body of an adjusting-screw, E, passes downward into the.

threaded opening a". Between said opening d and the front end of said plate is a second opening, d, from which a slot, d, extends diagonally rearward and outward, as shown.

The device thus constructed is used as follows, viz: Thread f, from a spool, F, is passed through the slot, d into the opening (1, and from the same passes forward between the plate D and bearing 13, and thence to the needle. By means of the screw E the pressure upon the thread and the consequent resistance offered to its passage between the impinging surfaces may be regulated at will. Should a lump or knot exist in the thread, it will readily pass between the pressure-surfaces without materially altering the tension, as at its entrance between, and until it reaches the center of said surfaces, the bearing B will rock downward at its rear end, and as said knot passes forward of the center will rock forward and downward, thus accommodating itself to the position of said knot, and enabling said spring-plate 1) at all times to have a bearing upon the said thread upon one or the other side of the obstruction.

Having thus fully set forth the nature and merits of my invention, what I claim as new 1s 1. In combination with the pivoted bearing B, provided with the arm I), the boss (0, provided with a notch limiting the up-anddown play of the arm, and so the swing of the bearing in both directions 011 its pivot, sub stantially as and for the purpose described.

2. In combination with the spring-plate provided with a suitable thread-opening, the

boss a supporting the rear end of the plate, I5 the boss a and the pivoted bearing B thereon, having arm 12, the boss a, having notch a, eugaging the end of such arm, and the thumbserew passing down through the spring-plate and tapped into the boss at, substantially as 20 and for the purpose described.

In testimony that I claim the foregoing I have hereunto set my hand this 13th day of November, A. D. 1883.

OSXV ELL H. ST. JOHN.

Vitnesses:

ASHTON H. Conn-mu, RATHBURN FULLER.

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