US152349A

US152349A - Improvement in portable derricks

Info

Publication number: US152349A
Authority: US
Publication date: 1874-06-23
Anticipated expiration: 1891-06-23

Description

UNITED STATES PATENT OFFICE.

HUGH DONNELLY, OF NEVARK, NEr JERSEY, ASSIGNOR T() PATRICK BRADY, OF SAME PLACE.

IMPROVEMENT IN PORTABLE DERRICKS,

Specification forming part of Letters Patent No. 152,349, dated June 23, U74 application tiled April 14, 1874.

To all whom it may concern:

Be it known that I, HUGH DONNELLY, of Newark, in the county of Essex and State' of New Jersey, have invented an Improvement in' Portable Derricks, of which the following is a specification:

My invention relates to an improved mode of anchoring or balancing a portable derrick. Its object is to dispense with the heavy deadweights or guys now commonly used to prevent the dcrrick from tilting toward the weight that is bein g raised.

As these guys must be released, and the dead\veiglits removed, to permit a change in the position ot' the. derrick, the objection to their use, and the value of an invention that will dispense with it, must be apparent.

A derrick embodying my invention, as represented in the drawing hereto annexed, consists of a platform, a central pulley, I1, the rear pulley d, the forward pulley c, the hoistingrope j', the jilo-pulley G, the weight a, and the usual frame of a derrick, consisting ot the jib, the upright, the boom, &c.

The construction of my invention is as follows: rlhc hoisting-rope fruns from the bucket or other weight a, over a pulley, Gr, on the outer end of the boom; thence under pulley c; thence over the central pulley b,- thence under the rear pulley d; and thence off to the hoisting` power.

By this combination of pulleys, it will be found that the tendency of the derrick to tilt toward the weight a will be countcracted without the aid of dead-weights, guys, or other equivalents. The relative positions of the three pulleys depend onthe height of the derrick and the bulk to be raised, and cannot be specified further than by stating that the pulley b must always be located between the two end pulleys c and d when the latter are used, and that increasing the distance between the upright and the central pulley b will increase the power to overcome the tendency of thc derriek to tilt toward the weight.

rlhe hoisting-rope should generally pass under the two end pulleys, and over the central one. Manifestly, however, many variations may bc made from the specific mode of construction herein represented, such, for instance, as locating the pulley b in the upright at a sudicient height to dispense with the rear pulley d, or locating` the pulley c within the upright, or dispensing` with the pulley c under the present construction. All such modifications I claim generally as within thc principle of my invention, which consists in using the pressure caused by the strain upon the hoisting-rope as a means of balancingthe derriek.

' I specially claimi 1. In a portable derriok or similar hoistingmachine, the wheel b, placed between the pulleys c and d, substantially as described, and for the purposes set forth.

2. In combination'with the frame and platform of a portable derrick, the wheel b, pulleys c, d, and g, and rope f, substantially as dcscribed, and for the purposes set forth.

, HUGH DONNELLY.

Witnesses:

FEED. HEWITT', HORACE HARRIS.