US98000A - Improvement in hoisting apparatus - Google Patents

Description

NEFEIERs, PHOTO-LITHOGRAPHER. WASHINGTON n C UNITED ASTATES PATENT OEEIoE.

THOMAS A. WESTON, OF RIDGEWOOD, NEW JERSEY, ASSIGNOR TO WILLIAM SELLERS AND JOHN SELLERS, JR., OF PHILADELPHIA, PENNSYLVANIA.

Specification forming part of Letters Patent No. 98,000., dated December 14, 1869 patented in England, August 28, 1868.

To all whom it may concern? Be it known that I, THOMAS A. WESTON, of Ridgewood, in the county of Bergen and State of New Jersey, have invented a new and useful Improvement in Hoists, of which the following is a full, clear, and exact description.

)'The object of myinvention is to provide an efficient device by the use of which, in'hoistid g machinery, the rotating power may be applied to raise or lower the weight, as required, agnd upon the withdrawal of the., power the 41,weight shall become instantaneously self-susyainin g, thereby obviating all risk of accidents 'rom the sudden descent of theweight, which,

requently occurs from the failure of the check- 4 n such machinery as heretofore constructed, i

' y ng-gear or the accidental withdrawal of the "power.

The principle of my invention consists in roducing sustaining-friction by the applicaytion, through helical inclines, of pressure upon j frictional surfaces; and my invention consists in combining, with a driving-shaft, helical inclines, frictional surfaces, and a pawl and y ratchet, or their equivalent, the parts being so combined that the ratchet-wheel (whose rotation in the direction to lower is prevented by d, the pawl) shall be made loose or fast upon the drivin g-shaft by the application or withdrawal I of the power required to lower.

In the accompanying drawings, Figure l is i i a View, in elevation, of a hoisting-crab, showing the application of my improvement; Fig. f 2, a vertical transverse section of the saine at the line a: of Fig. l; Fig. 3, a horizontal transverse section of a portion of the drivingshaft at the line y y of Fig. 2; Fig. 4, a view, in perspective, of the pinion of the drivingshaft, showing the helical incline formed thereon; Fig. 5, a view, in elevation, of a portion of the driving-shaft, with the helical inoline upon the ratchet-wheel instead of the pinion; and Fig. 6, a similar view, showing a double helical incline, operating to arrest the descent of the weight in either direction.

A driving-shaft, A, to which the rotating `power is applied through a crank, A2, is mounted in bearings in a frame or housings, B. A pinion, A1, and a ratchet-wheel, l), are placed contiguous to each other, and both loose upon the shaft Aand between two col-V f lars, E E', made fast thereon. A helical inoline, a, is formed upon the side of the pinion A1 adjacent to the collar E, upon which isl The side of the collar E which is contigu-l ous to the ratchet-wheel forms a frictional surface, against which the said ratchet-wheel is pressed, to be made fast upon the shaft, by the action of the helical incline a upon the helical incline a, the ratchet-wheel and pinion being thereby clamped firmly between the collars E and E'. 1

A pawl, d, arranged in such relation to the teeth of the ratchet-wheel as to operate, when the power is withdrawn, to prevent the rotation of the ratchetwheel in the direction proper for lowering the weight, is pivoted upon the upper brace-rod, b, of the frame, and, when the ratchet-wheel is made fast upon the shaft A, engages its teeth for that purpose. The pinion A1 gears with a spur-wheel, O', of larger diameter, secured upon a drum-shaft, 0,011 which the hoisting-rope is wound.

The operation of the hoist is as follows: The crank A2, being rotated in the direction proper for hoisting, as shown by the arrows, the helical incline a of the collar E, which, as

`hereinbefore stated, is fast upon the drivingshaft, bears upon the corresponding incline a, and clamps the pinion and ratchet-wheel firmly Y against the frictional surface of the collar E',

thus holding the pinion and ratchet fast upon the shaft and rotating them with it. The pinion A, gearing with the wheel C', rotates the drum-shaft O and elevates the weight. Upon Y the withdrawal ofthe power, the pawl d catches the ratchet, which is now fast upon the shaft, and holds the weight stationary, and the greater the weight may be upon the hoistingrope the more firmly will the ratchet-wheel be held fast upon the driving-shaft by the clamping action of the helical inclines and frictional surfaces.

It will be seen that the weight can only be lowered by applying power to the crank in a reverse direction. The helical incline a', having its motion reversed, thereby slackens its bearing upon the incline a and releases the ratchet from friction with the surface on the collar Ef, causing it to be loose upon the shaft, which revolves freely within it, while the power is applied to lower the weight, the pawl preventing its rotation.

Immediately upon the withdrawal of the power, the action of the weight attached to the hoisting-rope causes the incline a to bear against the incline a', and the ratchet-wheel is again clamped fast upon the shaft, and held more firmly the greater th eweight may be. The pawl d, engaging the ratchet, prevents the rotation of the shaft until the power is again applied, when, by the backward motion of the crank, the ratchet is slackened and the weight lowered, as before described.

It will be seen that upon the withdrawal of the power it is impossible for a sudden descent of the weight to any distance greater than the length of a single toot-h of the ratchet to occur. There is no possibility of the ratchet slipping upon the drivin g-shaft, as the increase of the weight only tends to clamp it more iirmly.

Various modifications of my invention may be made without affecting its principle, according as convenience of construction or location of parts may suggest.

Fig. 5 shows a form of my invention adaptable to quick lowering. In this case thc helical incline a is formed upon the ratchet-wheel, and

its corresponding incline a upon the collar E. Upon the slackening of the bearing of the inclines and frictional surfaces for lowering, the ratchet-wheel and shaft remain stationary and the pinion revolves loosely on the drivingshaft, the descent of the weight being arrested at pleasure by a slight forward movement of the crank.

Fig. 6 shows another form of my invention, similar to that shown in Fig. 1, but having helical inclines extending in two directions, so that the descent of the weight may be checked upon the withdrawal of the power for either direction of rotation of the rope-shaft.

A similar construction may be made for quick lowering by forming a double helical incline upon the ratchet.

Vhat I claim, and desire to secure by Letters Patent, is

The combination, with a hoist, of helical inclines, frictional surfaces, and a pawl and ratchet, or their equivalent, operating substantially as set forth. i

In witness whereof I have hereunto subscribed my name.

THOS. A. WESTON. i Witnesses: l

HENRY BALDWIN, J r., J. SNowDEN BELL.

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