US739992A - Yieldable pitman for power-hammers. - Google Patents

Description

No. 739,992. r PATENTED SEPT. 29, 1903.

, F. I. DAVIDSON & G. T. STRITE. YIELDABLE PITMAN FOR POWER HAMMERS.

APPLICATION FILED MAY 13- 1902.

N0 MODEL.

ll/Mme sses.

the striking bar.

UNITED STA ES I Patented September 29, 1903.

PATENT O FICE.

FRANK F. DAVIDSON AND GEORGE T. STRITE, QF TAMA, If) W-A.,

Yl ELDABLE PITMAN FOR POWER-HAMMERS.

SPECIFICATION forming part of Letters'Patent No. 739,992, dated September 29, 1903. Application filed May 13, 1902- Serial No. 107,208. (No model.)

To all whom it may concern:

Be it known that we, FRANK F. DAVIDSON and GEORGE T. STRITE, citizens of the United States, residing at Tama, in the county of Tama and State of Iowa, have invented certain newand useful Improvements in Yield-' able Pitmen for Power-Hammers, of which the following is a specification. I

This invention relates to that class of pitmen used for imparting a cushioned reciprocating motion to a movable part-such, for example, as the striking-bar of a power-hammer-and for the purposes of this application the pitman is illustrated in connection with such hammer, and the entire mechanism will be fully hereinafter described.

In the drawings, Figure 1 is a side view in perspective of a hammer embodying our invention. Fig. 2 is a fragmentary view in perspective showing the mounting of 4 the eccentric and the belt-tightener. Fig. 3 is a central vertical section of the shackle conmeeting the eccentric with the striking-bar. Fig. 4 is a sectional view showing the construction of the driving-pulley and the application of the brake thereto. Fig. 5 is a cross-section of the striking-bar through the pivotstud.

In the drawings, A is the base of the machine, composed of a pair of stout timbers separated by a standard or post B at the back end and by a block of corresponding thickness 0 at the front end. On the front end of the base is bolted the anvil-block D, adapted to take a suitable die F. To the upper end of the post is bolted an angle-block G, having bearings G for the pivot H of the striking-bar I. The latter is a straight piece of rectangular steel, and to its front end is bolted a die-block F. The pivot of the striking-bar is shrunk in the bar and has trunnions j ournaled in the bearings of the angleblock. g

In suitable bearings J, secured to the base, is mounted a shaft K, provided with a drivin g-pulley L. Midway between the baseblocks an eccentric M is secured to the shaft.

To its upper strap is connected a rod N, threaded up a considerable distance from the lower end and connecting about midway with a shackle having a pivotal connection with This shackle comprises a by bolts P.

having upwardly-extending arms IV.

pair of outwardly-curved arms 0 O, hinged to be secured frictionally to the striking-bar The lower ends of the arms connect by. links Q Q with a knuckle R, and through this knuckle passes the eccentricrod and is secured thereto at any desired point by jam-nuts S S.

The upper un threaded end of the eccentric rod passes through a'guide-block T, provided with lateral bosses T to take the end of coiled springs U U. The other ends of the springs rest on similar bosses projecting inwardly from the arms. the eccentric-rod up or down compresses the springs until the force of the springs is sufficient to overcome the inertia of the strikingbar, when it partakes of the movement of the rod. The shackle thus forms a double-act ing and very efficient cushion for the striking-bar, and in practice admits of nice manipulation, either for light or heavy service. The lift of the hammer may be varied at pleasure by moving the jam-nuts up or down, and both the position and the action of the hammer may be varied by shifting the clampplates on the striking-bar.

In bearings V Vis mounted a rock-shaft W,

Between two of these is mounted a tightenerpulley X. Two of the arms connect by links Y Y with a foot-lever Y. To the shaft W is also hung a brake Z, linked to the foot-lever at Z and adapted to engage one of the flanges of the driving-pulley on the lower side. The counter movement of the foot-lever is secured by a spring Y drawing back the tightenerpulley as soon as the foot is lifted and at the same time applying the brake.

Proper Weight is given to the driving-pulley to secure the desired momentum by fasten: ing to or forming ,on its sides heavy flanges L, the inner one of which forms a bearing for the brake. It will be seen that these flanges are made eccentric to the pulley, the longer radius of the brake-flange being down when the striking-bar is up. By this arrangement the brake catches the pulley at such a time asto stop the hammer with the bar up. The other flange is set over oppositely, so as to balance.

It will be seen that a movement of Having thus described our invention, what we claim as new, and desire to secure by Letters Patent, is-

The combination in a pitman, of a shackle comprising a pair of arms hinged together at one end and a connection thereof with the striking-bar, a knuckle and pair of links connecting" the other ends of the arms, a guideblock, a pair of springs mounted between the 10 guide-block and the arms, and a reciprocating rod mounted to slide a limited distance in said guide-block, and secured to the knuckle, substantially as described.

In testimony whereof we aifix our signatures in presence of two witnesses.

FRANK F. DAVIDSON. GEORGE T. STRITE. Vitnesses:

NELSON E. KNIGHTS, JOHN W. ROBINSON.

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