US118928A - Improvement in sewing-machines - Google Patents

Description

UNITED STATES PATENT OFFICE.

IMPROVEMENT IN SEWING-MACHINES.

Specication forming part of Letters Patent No. 118,928, dated September 12, 1871.

To all whom 'it may concern:

Be it known that I, FRANCIS ELIJAH HAHN, of Philadelphia, county of Philadelphia, State of Pennsylvania, have invented certain Improvements in Sewing-Machines, of which the following is a speciiication:

Myinvention consists of certain improvements in sewing-machines, too fully explained hereafter to need preliminary description, the said improvements having been designed with the view of producing a machine of simple and economical construction and of overcoming the effects of wear.

Figure l, Drawing No. 1, is a vertical section of a sewing-machine with my improvements; Fig. 2, an inverted plan view; Fig. 3, Drawing No. 2, a transverse vertical section on the line 1 2, Fig. l; Fig. 4, a plan view of the guides for the needle and pressure-bars; Fig. 5, a vertical section on the line 3 4, Fig. 3; Fig. 6, a sectional view of the bearings of the driving-shaft, and Fig. 7, a sectional plan, showing the fulcrum of the needle-arm.

A is the base-plate of the machine, B, the stationary arm C, the needle-arm; D, the needlebar; E, the pressure-bar; and F, the drivingshaft. To this driving-shaft are secured, by setscrews e e, conical sleeves a c, arranged to turn in projections b b on the under side ofthe baseplate A, so that when the driving-shaft becomes loose the sleeves may be adjusted more tightly in their bearings, and secured by the screws after adjustment, there being in the projections or bearings Z) elongated holes to permit the access of a suitable instrument for operating the said screws. From a disk, G, on the driving shaft projects a pin, f, which passes through the curved slot h on the needle-arm, this slot being formed by and between two plates, i and i', the former of which is permanently secured to the needle arm, while the plate t" is secured to the plate i by set-screws j j passing through elongated holes in the plate t', so that the plate i can be readily adjusted nearer to the plate i when, through continued wear, the crank-pin becomes loose in the curved slot. The conical fulcrum-pin m, Fig. 7

upon which the needle-arm turns, is adapted to and driven tightly into conical holes formed for its reception in the stationary arm, as shown. When the needle-arm becomes loose on the pin the latter is driven back slightly, as indicated by the arrow, and is secured to the needle-arm by a set-screw, n, with which the arm is provided, the said needle-arm then vibrating with, instead of upon, the pin, and the latter turning in the conical holes of the fixed arm. The needlebar D and pressure-bar E are square, and arranged, as shown in Fig. 4, so as to slide in V- shaped grooves in the end A of the needle-arm, and the plate I secured to the same. The looseness of needle-bars, owing to constant wear and the absence of provisions for tightening them, is a source of much complaint b y operators of sewing-machines; by arranging square bars i'n the manner described, however, they can be readily tightened by turning the set-screws p 19, by which the plate I is secured to the stationary arm. In order to insure delicate adjustment, however, I interpose between the plate and arm two wedges, q q, which can be so adj usted as to determine the exact distance between the plates for insuring the free movement of the bars without any lateral play. The needle-arm has an elongated slot for receiving a roller on a pin projecting from the needle bar. The pressure-bar E is made cylindrical at the upper end, which projects into and is arranged to slide in a bar,E/, similar in shape to the pressure-bar below, but iixed between the plates H and I by a set-screw, s, as shown in Fig. 4. A spiral spring intervenes between the stationary bar E and pressure-bar E, and tends to force down the latter, which can, however, be elevated by the cam-lever J, Fig. 3. The shuttle K is carried by a driver, L, which is arranged to slide on a bar, m, and to which is jointed one end of a rod, u, the opposite end of which is connected to a pin, t, rendered adjustable in a curved slot in an arm, u, which is secured to the crankpin j'. As the curved slot in this arm uis eccentric as regards the crank-pin, more or less throw may be imparted to the shuttle-driver by simply adjusting the pin in the slot. I? is the feed-bar, having at its outer end the usual serrated surface projecting through a slot in the work-plate of the machine. This feed-bar is arranged to slide inl transverse guides on the base-plate, and carries an adjustable screw, Q, shown in Fig. 8; and between the end of this screw and a pin, zo, on the bar, projects the end of one arm of the lever' R, hung to a pin, w, on the under side of the base-plate, the other arm of the lever terminating in a sharp edge, y, formed by beveling each side. A disk, T, on the driving-shaft'has two pins, c c, so situated that, as the disk revolves, one pin Will strike one lbeveled side and the other the other beveled side of the lever R, and thus impart through the lever the desired intermittent reciprocating movement to the feedbar, and the extent of this movement Will depend upon the distance of the end of the screW-rodQ from the pin w. Those familiar With sewingmachines will readily understand the operation of the above-described parts Without further eX- planation.

I claiml. The shaft F, provided with conical sleeves c, secured to and turning with, but adjustable on the shaft, in combination with the bearings b b, recessed to receive the said sleeves7 as set forth.

2. The combination, With the needle-arms7 of the plate i secured to the arm, the plate z" adjustable on the plate i, and devices for adjusting` and securing the plate after adjustment, the two plates being recessed to' form a slot, h, as set forth. A

3. The tapering pin m, having bearings in the stationary arm, in combination With the needlearm and its set-screw, so that the pin may be rotated in its bearings, as and for the purpose described.

4. The shuttle-driver, connected to a rod, N, rendered adjustable on an eccentrically-slotted arm, u, secured to the crank-pin on the drivingshaft, as set forth.

In testimony whereof I have signed my name to this specification in the presence of tWo subscribing Witnesses.

F. E. HAHN.

Witnesses:

WM. A. STEEL, F. B. RICHARDS.

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