US373571A - Bridge-spring action for oscillating-platen presses - Google Patents

Description

' (No Model.)

J. THOMSON.

BRIDGE SPRING ACTION FOR OSGILLATING PLATEN PRESSES.

No. 373,571. Patented Nov. 22, 1887.

UNITED STATES ATENT FFICEQ JOHN THOMSON, OF BROOKLYN, NEW YORK, ASSIGNOR TO THE COLTS PATENT FIRE ARMS MANUFACTURING COMPANY, OF HARTFORD,

CONNECTICUT.

BRIDGE-SPRING ACTION FOR OSCILLAIING-PLATEN PRESSES.

SPECIFICATION forming part of Letters Patent No. 373,571, dated November 22, 1887.

(No modelil To all whom it may concern.-

Be it known that 1, JOHN THOMSON, a citizen of the United States, andaresident of the city of Brooklyn, Kings county, State of New York, have invented certain new and useful Improvements in Bridge-Spring Actions for Oscillating-Platen Presses, of which the following is a specification.

This invention consists in a device for controlling the platen action of jaw-presses of that class in-which the platen is caused to slide directly to or from the bed prior and subsequent to the instant of impression, but during all other portions of its action to roll on a table or seat.

The figure of the drawing represents a vertical end elevation ofsuch a platen action,showing the application of my invention, in which the numeral 3 represents the bed; 4, the side frame; 5, the rocker-seat; 6, the platen; 7, the rocking block or bridge; 8, the rocker; 9, the ear of said rockingblock, and 10 the lugs forming a part of the ear, and which engage the rocker-seat during the direct sliding action. Motion is imparted to the block by a connectingrod, 11, journaled on the blockshaft 12, the extension of said connecting-rod being connected with the power member-- such as a crank or toggle arranged to impart a reciprocating motion to the rod-all as in common practice.

The usual mode of controlling the motion of such rocking blocks is to pivot a link, as 13, to the block, as at 14, the extension of the link being guided in a barrel containing a spiral spring, and thebarrel fixedly journaled to the frame, the spring, thus acting directly in the plane 15 of the link,exerting its tension between the link and the barrel. The function of the spring is to permit the block and platen to be drawn forward, as represented by dotted outline 16, but to thereafter actas a fixed member, free to vibrate with the block and to cause the block to roll properly.

The objections to such arrangements are, first, in that the available space directly under the block is exceedingly limited; second, the spring or springs require to be exceedingly powerful. and, in consequence of the limited space, of incorrect proportions.

. The reason why such powerful springs are required to control a rocking motion, so called, has not usually been understood, and hence has resulted in the use of springs entirely inadequate for the required duty. The said reason is that the center 14, if permitted to act freely with the rocking block, would describe the are ofa cycloidal curve, as 17, in constructing which the rocker8 is the describing circle, whose center is at 18; but as the link which swings on the center 19 describes the arc of a circle, as 20, and the rocker is forced to partake of the motion of the link, it is evident that the rocker rolls and grinds differentially, like a differential mill; and in consequence of this and the usual weight of such rocking blocks and platens, great friction is thereby developed. To meet these difficulties in the best manner by the use of a spring action, I mount the heel 19 of the link in a lever, 21, which lever is journaled at 22 in the frame. pivotally connected to a slide-rod, 23. A retaining-rod, 24, or two rods, one on either side of the slide-rod,is also pivotally connected to the frame, as at 25, having a slide, 26, fixedly secured to the said rod or rods, which acts as a guide to the slide -rod 23.

Between the slide and the nut 27 and upon the slide-rod is mounted a spring, 28, which acts by extension to normally hold the lever against the stop 29. The consequence of this arrangement is that the spring may be given any desired control of the bridge, either by proportion of leverage or by extent of spring, or both, as this construction and disposal of the parts in a usually-unoccupied space permits the use of a spring and lever of ample proportions for the required duty.

The broken line 30 indicates the center of the lever when the platen is on theimpression, while the line 31 and outline 32 indicate the position of the link and block at the extreme ofthe rocking action.

The arrangement of the link shown in the figure represents its best theoretical positionthat is, in which the arc of the circle 20 and the arc of the cycloid 17 intersect at the beginning and end of the action. In this wise the slip is reduced to the minimum; but in special instances it is required to increase this slip. In this device this may be readily ac The extension of the lever 22 is complished by simply raising or lowering the center 33 of the lever, the eflect of which is to cause the path of the circle 20 to pass within or beyond the present intersecting point 34:.

5 The precise arrangement here shown may be departed from without affecting the principle and advantages of this invention-as, for instance, the lever 21, having its journal at 22, and bearingfor the heel of the link, as

IO shown, might be projected to form a bellcrank by the extension 22*, the spring-connection being vertical or at any angle where the springs might be best arranged; also that a plurality of springs may be used, instead of 15 the single spring shown in the drawing.

I claim- 1. The combination of the rocking block,

JOHN THOMSON. l Witnesses:

WILLIAM THOMSON, v OLIVER N. PAYNE.

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