US554890A

US554890A - Hoist

Info

Publication number: US554890A
Authority: US
Publication date: 1896-02-18
Anticipated expiration: 1913-02-18

Description

UNITED STATES u ATENT OFFICE.

HERMAN MEIEH, OF PHILADELPHIA, PENNSYLVANIA.

HOIST.

SPECIFICATION forming part of Letters Patent No. 554,890, dated February 18, 1896.

Application filed May 2l, 1895. Serial No. 550,05 7. (No model.)

T0 all whom, it may concern:

Be it known that I, HERMAN MEIER, a citizen of the United States, residing at Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented certain new and useful Improvements in Hoists, of which the following is a full, clear, and exact specification.

My invention relates to a new and useful improvement in hoists, and has for its object to provide such a device which shall produce a continuous motion of the lift-chain in either its upward or downward movement by a set of reciprocating pawls, to which motion is imparted by a series of cams actuated by a hand or chain wheel.

Vith this end in view the invention consists in the details of construction and combination of elements hereinafter set forth and then specifically designated by the claims.

In order that those skilled in the art to which my invention appertains may understand how to make and use the same, I will describe its construction and operation in detail, referring by number to the accompanying drawings, forming a part of this specification, and in which- Figure l is a perspective of my improved hoist; Fig. 2, a vertical section taken so as to show one set of ratchets and their pawls; Fig.

V3, a similar view looking from the opposite side and showing the other set of ratchets and their pawls; Fig. 4,a sectional plan view showing the relative position of the ratchets and pawls, and Fig. 5 a detail perspective of the eccentrics.

Similar numbers denote like parts in the several views of the drawings.

1 represents the casing of any convenient form to support the several operating parts of the device, and 2 is the lift-chain wheel, having formed in its periphery a groove provided with the usual cogs, with which the lift-chain 3 is adapted to mesh in the wellknown manner. Formed with or secured to this wheel are the ratchet-wheels 4:, preferably four in number and set out of alignment with each other that their teeth divide the space occupied by one tooth of each wheel into four equal parts, for the purpose presently explained. Y This nest of wheels isjournaled upon the shaft 5, secured in the frame 1 by nut 6.

7 is a shaft journaled within the frame l, and upon this shaft is formed the stepped eccentrics S, as shown in Fig. 5, and for the purpose to be hereinafter explained.

9 are pawls, the rear ends of which are so formed as to embrace the eccentrics 8 and receive motion therefrom. At the forward end of each of these pawls is formed a nose 10, adapted to iit the circular notches 11 of the ratchet-teeth, and 12 are extensions formed Vwith the pawls and adapted to bear against the pin 13, extending across the frame of the device. 14 are suitable springs bearing upon these extensions to hold them in their normal position.

On one end of the eccentric-shaf t 7 is placed a hand chain-wheel 15, whose periphery is so formed as to be adapted to a chain 16, by which motion is imparted to the wheel. Upon operating the chain-wheel in the direction of the arrow the pawls 9 will be caused to reciprocate by the eccentrics, and this motion will be im parted to the ratchets by the engagement of the noses 10 with the teeth of said ratchet, and as the eccentricities of the eccentrics are ninety degrees apart and the teeth of the ratchets set correspondingly relative to each other it follows that first one pawl will operate upon its ratchet and when nearing the dead-center of its eccentric will slow up, permitting the pawl actuated by the next eccentric, which will be moving at a greater speed, to come into engagement with the teeth of its ratchet and carry the first-named tooth without the iield of action of the first-named pawl, and this operation will be taken up and repeated by each pawl in turn, as it nears its position of fastest movement, so that the chain-wheel 2, during -the revolving of the camshaft, will receive a continuous motion from the reciprocating pawls. Thus it will be seen that a very powerful strain may be brought to bear upon the lift-chain wheel to enable it to accomplish its function.

In reversing the movement of the wheel 2, to lower its chain or weight carried thereby, the hand chain-wheel l5 is turned in the opposite direction to the arrow, causing the pawls to be reciprocated, but lifting their rear IOO ends upon the iirst part of their stroke instead of depressing them, as is the case when the wheel l5 is turned in the direction of the arrow, as before described, and since the noses l0 of the pawls fit the notches 1l of the ratchets said ratchets will be moved backward by said pawls until the curved ends of the extensions l2 come in contact with and ride upon the pin I3, when said noses will be lifted clear of the ratchet-teeth, as will be readily understood by reference to Fig. 3, and since the pawls do not work in unison, as before described, it follows that one or more of the noses l0 will be in engagement with the notches 1l at all times, so that the ratchets will never be free to move backward faster than the pawls. By this arrangement the lift-chain wheel is enabled to sustain any weight within its capacity without backing, as the eccentricity of the eccentrics is not suiiieient to overcome the inertia of the eccentric-shaft wheel l5 by the thrust of the pawls thereon.

A great advantage gained by my construction is that the slack in the lift-chain maybe taken up until said chain is taut and the load ready to be lifted by simply pulling upon the opposite end of said chain, as the pawls will ride upon the teeth of the ratchets, thus permitting the liftchain wheel to revolve during this process; also, when it becomes desirable to lower the lift-chain rapidly the pawls may be thrown out of engagement with the ratchets by any suitable mechanism, when the liftchain wheel will be free to revolve backward.

While I have shown four ratehets and pawls, it is obvious that a lesser or greater number might be used to accomplish the same result, depending upon the maximum load intended to be lifted by the hoist, as the greater the number of ratchet-wheels, pawls, and eccentries used the greater the capacity of the device, since the pawls would act upon the ratch ets through a smaller part of their reciproca tion, and that part would be when the eccentries were nearer their dead-centers, thereby increasing their power upon said pawls.

Having thus fully described my invention, what I claim as new and useful is- 1. In a hoist, the combination of a shaft, a hand chain-wheel mounted thereon, stepped eccentrics arranged on a second shaft, a ratchet having a series of teeth set out of alignment, pawls operated by the eccentrics and having noses engaging the ratchet and provided with an extension along the nose, a pin on which the extension rides to elevate the noses out of engagement with the ratchet teeth, for the purpose described.

2. In a hoist, the combination of a shaft, a hand ehain-wheel mounted thereon, stepped eecentrics arranged on a second shaft, a ratchet having a series of teeth set out of alignment,pawls having semicircular recesses in their ends to embrace the eccentrics and 011 their opposite ends a nose to engage the ratchet-teeth, and a curved extension above the nose riding on a pin to elevate the nose out of engagement with the ratchet-teeth, as and for the purpose described.

In testimony whereof I have hereunto affixed my signature in the presence of two subscribing witnesses.

HERMAN MEIER. INTitiiesses:

S. S. WILLIAMSON, E. C. WURDEMAN.