US167398A - Improvement in derricks - Google Patents

Description

B. FREEMAN.

Derrick.

No, 167,398, Patented Sept. 7, 1875.

INVENTOR N. PUERS. PHOTO-LITHOGRAPHEH, WASHINGTON D C (5F ONE-HALF HIS RIGHT TO JAM VERMONT.

BARTON FREEMAN, OF EAST ATTLEBOROUGH, MASSACHUSETTS, ASSIGNOR I ES MOANERNEY, OF ATTLEBOROUGH,

IMPROVEMENT IN DERRICKS.

Specification forming part of Letters Patent No. 167,398, dated September 7, 1875; application filed May 6, 1875.

do hereby declare that the following is a full,

clear, and exact description thereof, which, with the accompanying drawings forming part of this specification, will enable others skilled in the art to make and use the same.

Figure I shows my improved derrick in elevation. Fig. II is an enlarged view of the power-multiplying device. Fig. III is a top view of the same.

Similar letters of reference indicate corresponding parts.

The object of the invention is to produce a simple device for lifting heavy weights by manual power, and also for lowering the same by a simple movement of the same device.

The nature of the invention consists in the peculiar arrangement of lever, pawl, ratchetwheel, and check-pawl with springs, so that in one position the check-pawl will prevent the chain-wheel from turning backward, and in the other position the check-pawl is kept clear of the ratchet-wheel, and allows the same and the chain-wheel to turn backward and so lower the load, until the lever is raised to a given point, when the check-pawl engages with the ratchet-wheel again, and so holds the weight.

In the drawings, A is a long handspike or lever secured to the curved lever 12. This curved lever is supported on the same shaft which is secured to the ratchet-wheel and chain-wheel, and which turns in journals made in the iron frame of the third leg of the derrick. G is the ratchet-wheel, and l the chainwheel. These are preferably made in one piece, but can be made separately and secured to the same shaft, so as to act together. E is the check-pawl secured to the frame by a pin, on which it turns. f is a spring resting on the curved lever 12, and secured to the rod K, having the end where it is secured to the rod K turned up, as shown at i, so as to form a shoulder. g is a spring secured on the curved lever 12 close to the pawl d. The blocks and falls are of the usual construction, made so as to sustain heavy weights, the chain from which passes over the chain-wheel l. When a heavy weight is secured to the lower hook of the block and fall, and the long lever A is raised, the pawl 01 passes over the ratchet-wheel G, and when the lever is lowered the pawl engages with the ratehet-wheel, and turns the same, and also the chain-wheel l, and thus exerts a strain upon the chain, and through the same a corresponding but greater strain through the block and fall upon the weight to be raised. By repeating the up-and-down motion of the lever A the weight is raised to any desired height within the limits of the derrick. When the mass is to be lowered the rod K is pulled down until the spring f is in the position indicated by the broken lines on Fig. II. By this motion the check-pawl E is raised sufficient to clear the teeth in the ratchet-wheel C, as shown in dotted lines, and when the lever A is raised the ratchet-wheel O and chain-wheel 1 will turn and pay out the chain, thus lowering the mass suspended by the block and fall. As soon as the spring 9 reaches the turned-up part z' of the spring f it is pressed over, and thus allows the checkpawl to engage with the ratchet-wheel, while the spring g, in passing over the turned-up end tof the spring f, disengages the pawl 01 from the ratchet-wheel by lifting the pin in the side of the pawl 01, and thus raising the same over the edge of the tooth, and by depressing the lever A the pawl engages with the tooth, and the spring f, being released, again lifts the check'pawl E, thus allowing a heavy mass to be slowly and safely lowered. By the vertical movements of the handle a, causing the curved upper surface of the lever 12 to change the tension of the spring f, the check-pawl E is automatically lifted from the ratchet when the handle a is raised to back the chain-wheel, and it is caused to engage with the teeth when the handle a is lowered to take a fresh hold of the ratchet; the shoulder on the spring f causing the spring g to rise and lift the pawl from the ratchet, and

permit the handle a to be lowered while the check-pawl E holds the ratchet, these two springs operating upon the pawls, and causing them to act like the escapements of a watch.

The whole operation of raising and lowering a heavy mass may be performed by one person without moving from his position at the end of the lever.

Stumps may be effectually pulled by this derrick by one man; and the same device may be arranged to form a part of other hoistingmachines for raising heavy masses and lowering the same by manual power, the same being strong, efficient, and simple in construction and manipulation.

Having thus described my invention,Iclain1 as new and desire to secure by Letters Patent v The combination, in a derrick, of the lever A, the curved lever b, the pawl 01, check-pawl E, and ratchet-wheel O with the springs g and f and rod K, the whole operating together substantially as and for the purpose set forth.

- BARTON FREEMAN. Witnesses:

JOSEPH A. MILLER,

WM. 0. CHASE.

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