US33929A - Improved hoisting-block - Google Patents

Description

- UNITED STATES PATENT OFFICE.

IMPROVED HOISTING-BLOCK.

Specication forming part of Letters Patent No. 33,929, dated December 17, 1861.

Charlottetown, Prince Edward Island, have invented an Improved Hoisting-Block, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, making part of this specification, in which- Figure l is a plan of the block, one side of the shell being removed. Fig. 2 is a section through the block on the line o@ :l: of Fig. l; Fig. 3, a detail to be referred to.

The object of my present invention is to produce a hoisting-block (for ships tackle and purchase blocks) which will combine the following features essential to a perfect block in a greater degree than any block heretofore constructed with which I am acquainted: first, smallvsize and lightness in proportion to the amount of weight or strain the block is capable of sustaining; second, the least amount of friction commensurate with its strength; third, great strength and non-liability of the bearings to be crushed or deranged either vby a great strain applied suddenly to them or by a great weight suspended -for a long time on the block; and my invention consists in a block having' a ring or central bearing of considerable diameter cast onto or otherwise suitably attached to the shell of the block and sur-rounded by a loose metal ring, (which serves the purpose of the sheave of ordinary blocks) and between which and the central bearing` is interposed l stand and use my invention, I will proceed to describe the manner in which I have carried it out.

In the said drawings the shell of the block (which I prefer to have made of brass or malleable iron) is divided into two halves A A2, which are held together by bolts a, and nuts l). The block is furnished at one end with a hook c and at the other with an eye or becket d. These are formed on the half A2 of the shell shown in Fig. 1, the cap-plate A being of less thickness at its ends, where the bolts a pass through it. Both parts have a circular opening B through the center.

From the inner face of the piece A2 rises a stout ring e, the outer edge 3 of which is embraced by the cap A. There are formed in the face of each plate A A2 grooves f g exterior to the ring e, forming rings et 5 6 7, which project up from the face of each plate. Aheavy ring C is placed between the two plates A A2. It is turned out at h to receive the rope, like an ordinary sheave, and has a rib l on its inner side, which fits between the rings 4 and 5. This ring C is of a somewhat greater diameter than the rings 4 and 5 and revolves freely outside of them. Between the ring C and the stationary ring e are placed friction-rolls m, of a greater diameter than the width of the grooves f and g, so that they rest on the rings 4 5 and 6 7 and lill the space between the rings C and e, the loose ring C rolling around on these friction-rolls. To prevent these rolls m from running in contact with each other and grinding together, another series of rolls 0, of less diameter but of greater length,is introduced, one between each roll m. rolls o lie in the grooves f and g and revolve freely therein.

Instead of the small rolls o, I sometimes employ blocks p, Fig. 3, which are curved out on each side to match the rolls fm, and areintroduced between the rolls m to keep them separate, but are not intended to receive the bearing of the ring C unless a weight should be applied to the ring sufficient to crush the rolls fm or to indent them into the ring. Before this, however, can take place to any considerable degree the ring C will be supported by the blocks p (when these are used, as in Fig. 3) or by the rings 4L and 5. Any required degree of strength may be given to the ring e, while the form of the shell with the opening B in the center allows the block to be made light in proportion to its power and strength,

vor in some case where lightness is not so much an obj ect the shell may be made wholethat is, without the opening B-and instead of the ring ea solid disk may occupy the center of the block and serve as a bearing for the friction-rolls m.

What I claim as my invention, and desire to secure by Letters Patent, is-

A hoisting-block having a loose metal ring C, (which takes the place of the sheave,) in combination with the central bearing e and the friction-rolls m, operating substantially as specified.

VATSON DUCHEMIN.

Witnesses:

THos. R. RoAcH, P. E. TEscHMAcHER.

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