US248449A - Lymon d - Google Patents

Description

(N o Model.) 4 4 L. D. GREEN, SEWING MAGHINE.

.No. 248,449. Patented Oct. 18,1881.

M 4;. R I

Hi l w i Iii! FQ H i 0,? 4 I, MUM. I 44W, 44W

UNTTED STATES PATENT @FFTCE.

LYM'ON D. GREEN, OF WATERTOWN, NEIV YORK, ASSIGNOR TO THE'DAVIS SEWING MACHINE COMPANY, OF SAME PLACE.

SEWING-MACHINE.

SPECIFICATION forming part of Letters Patent No. 248,449, dated October 18, 1881.

Application filed May 23, 1881.

To all whom a may concern:

Be it known that I, LYMON D. GREEN, of Tater-town, Jefferson county, New York, have invented a new and useful Improvement in Sewing-Machines, which invention is fully set forth in the following specification.

This invention has reference to the Davis and other sewing-machines which form a lockstitch by the aid of a shuttle; and it consists in improved devices for operating the shuttledriver.

The first point to gain in a sewing-machine is to use as little thread as possible in making the stitch, to prevent chafing the thread. To

do this it is necessary to give both the needle anti shuttle an irregular motion-that is to say, the needle should be slowed while the shuttle is passing through the loop, and then the shuttle should be slowed to allow the nee- (lle to gain its highest point at the same time that the shuttle reaches the end of its forward movement, so that the tension should come on both threads at the same time.

In the Davis sewing-machine, as heretofore constructed, the shuttle-driver, which consists of a lever pivoted upona vertical pin under the cloth-plate, has been operated from an cecentric on the main shaft by a back hanger or lever pivoted at the back or rear end of the 0 goose-neck, the eccentric working in an opening in the back hanger, and an adjustable shoe being used to compensate for wear. This arrangement accomplishes the desired movement; but, being placedoutside the goose'neck,

it is unsightly and liable to be in the way, and,

there is considerable wear which the adjustable shoe does not readily compensate for. In the present invention the desired irregularity of movement is secured with a lever located 40 within the goose-neck and operated by an ordinary eccentric and strap. The peculiar movement depends upon the relative position of the axis of the shaft, the fulcrum of the lever, and the point of connection between the strap 5 of the eccentric and the end of thelever. The parts should be so arranged that the end of the lever swings under the shaft during the forward stroke of the shuttle, the joint between the eccentric-strap and lever being be- No model.)

low the axis of the shaft, so that something more than half a revolution is occupied in said forward movement. To illustrate this action better reference may be had to the diagram, Fig. 3, of the accompanying drawings, which indicates the position of the parts at the beginning and end of the forward stroke of the shuttle. a7, 3 and z are the axis of the shaft, the fulcrum of the lever, and the joint at the end of the lever, respectively. The path of the center of the eccentric is shown by the circle 11, the effective length of the eccentricstrap by the line to, and the arm of the lever by t. In order to move the shuttle forward,

the eccentric must rotate from the point r to the point 8 in the direction of the arrow, Fig. 2, somewhat more than half a revolution, and, to return it, from s to r, or somewhat less than half a revolution, the size of the are being of course variable within certain limits by altering the proportions and positions of the vari- 7o ous parts. The shuttle, during the first part of its advance, moves rapidly, the extra time being consumed by a slowing movement which takes place after the shuttle has passed through the loop. The present invention enables the travel of the shuttle to be diminished about four-tenths of an inch from that made by the old style of back hanger.

Heretofore a lever pivoted in the goose-neck below the main shaft has been used in sewing- 8o machines to operate the shuttle-driver; but in such cases the upper end of the lever has been forked and a cam or cams upon the main shaft have been arranged to act upon the arms of the fork. In arrangements of this character there is considerable wear of the cam and of the contact-surfaces, and it is hard to compensate therefor-diificulties which are avoided by the use of the eccentric and strap encircling the same, and by the connection of the strap 0 with the lever by a hinge or loose joint.

The following description will enable those 7 skilled in the art to which the invention 1elates to make and use the same, reference being being had to Figs. 1 and 2 of the accom- 5 panying drawings, which illustrate what is deemed the best method of carrying the invention into effect.

Figure l is a view, in sectional elevation, of a portion of a sewing-machine embodying the invention; and Fig. 2, a view, in sectional elevation, in a plane at right angles to that of Fig. 1, showing the devices for operating the shuttle-driver.

A is the goose-neck of the machine; B, the main or driven shaft, turning in hearings in the gooseneck; and O, the fly-wheel, which is fixed by a set-screw or in any suitable way on said shaft.

D is a belt-pulley for communicating motion to the shaft and fly-wheel.

The eccentric G, for operating the shuttledriver, is fixed on the shaft B by means of a set-screw, g, through a boss on the side of the eccentric, as shown, or in any suitable way.

The strap H, which encircles the eccentric, is cut across and provided with an adjustingserew, I, so that the ends of the strap can be drawn together to adjust it to the eccentric, and to compensate for wear. On the lower side of the strap is a projection, h, by whicl1 it is hinged or jointed to the lever K. This lever is slightly bent, as shown in Fig. 2. It is fulcrumed upon the pin L, which fits in holes in the wall of the goose-neck. Its upper end is slotted to receive the projection h, with which it is connected by apivot-pin, M. A tapering pin-screw, threaded at the small end, and provided with a nut, m, is preferably employed.

The lower end of the lever is connected with the shuttle-driver in any ordinary or suitable way, such as the universal joint and disks used in the Davis and other sewing-machines, in which the shuttle-driver, formed by a horizontal lever, is operated by a lever vibrating in a vertical plane. The various parts are so proportioned that the motion of the shuttle is properly timed to that of the needle, as indicated in the first part of this specification.

Modifications may be made in the details of the machine withoutdeparting from the spirit oftheinvention. Theeccentricandstrap could be used with a lever not bent as shown, although this form of lever is deemed most advantageous for the purpose.

Having now fully described my said invention and the manner of carrying the same into effect, what I claim is- 1. The combination, with the shaft of a sewing-machine, of an eccentric fixed thereon, a strap encircling the eccentric, a lever for operating the shuttle-driver, and a pivot-pin connecting the lever with the said strap close to the eccentric, the length of the strap and of the operating-arm of the lever being relatively proportioned, and the axis of the shaft and fulcrum of the lever being relatively arranged, as described, so that the pivot-pin is moved toward and away from the line between the axis of the shaft and fulcrum of the lever, and when it is drawn forward an obtuse angle is formed by the lines extending therefrom to the said axis and fulcrum, substantially as set forth.

2. The combination of the shaft turning in bearings in the goose-neck, eccentric mounted on said sh aft, strap encircling the eccentric, and bent lever for operating the shuttle-driver, fulcrumed in the goose-neck below the shaft and pivoted at its upper end to the said strap close to the eccentric and below the center thereof, the said leverbeing bent slightly, so that the arms form with each otheran obtuse angle, and having the axis of vibration parallel to that of the said shaft, substantially as described.

In testimony whereofI have signed this specification in the presence of two subscribing witnesses.

LYMON D. GREEN. Witnesses:

LEVI A. JOHNSON, G. A. BAGLEY.

Images