US905309A

US905309A - Pulley-block.

Info

Publication number: US905309A
Application number: US37376007A
Authority: US
Inventors: William N Head
Original assignee: Individual
Current assignee: Individual
Priority date: 1907-05-15
Filing date: 1907-05-15
Publication date: 1908-12-01
Anticipated expiration: 1925-12-01

Description

W. N. HEAD.

PULLEY BLOCK,

APPLIOATION' IILED MAY 15, 1907.

905,309. Patented Dec.,1, 1903.

UNITED sTArns PATENT OFFICE.

WILLIAM renew, on NEW YORK, N. Y, ASSIGNOR 'ro enonen AGOBIAN, or

BROOKLYN,

NEW YORK.

PULLEY-BLOGK.

Application filed May 15,

tan, in the county of New York and State of New York, have invented certain new and useful Improvements in Pulley-Blocks, of which the following is a specification.

The object of this invention is to provide a new and improved pulley block which is simple in construction, strong, durable and reliable and is provided with a means for automatically locking the rope whenever the same is released or breaks, which means is automatically thrown out of action as long as the load is being raised or lifted and which means permits of lowering the load at any desired speed or checking its descent at will.

In the accompanying drawings, in which like letters of reference indicate like parts in all the figures: Figure 1 is a side view of my improved pulley block. Fig. 2 is an edge view of the same. Fig. 3 is an enlarged longitudinal sectional view showing the locking means.

The pulley block is constructed with a casing composed of two side plates A, a central partition B between and parallel with the side plates and top, bottom and intermediate cross bolts C, D and E respectively, 011 which latter the sheaves F are mounted between the side plates A and the partition B. A suspension hook G is swiveled in the top of the casing and an eye H for securing the fixed end of the suspension or hoisting cable is formed at the bottom of one side plate. Above the sheaves F a cross bolt or pin J is secured in the casing and on the same the two locking levers K are mounted, one in each compartment formed by a side plate A and the partition 13. The locking levers K are alike and each has a long shank or arm L and a shorter shank M united by a cross piece N. A short link 0 is pivoted between the ends of the longer shanks 'or arms L of the two levers K thus uniting the two levers at their outer ends and a check rope is to be fastened to said link or its substitute. At the inner end of each lever K a shoe P is formed which has a curved groove Q, eccentric to the pin J and extending to the free end of the shoe and provided with inclined curved rifiles corresponding to the twists of the rope. Each shoe also has a smooth grooved part R Specification of Letters Patent.

1907; Serial No. 373,760.

Patented Dec. 1, 1908.

l which when the lever K. is in the position shown in Fig. 3 is substantially concentric with the sheave and does not interfere with the movement of the rope. A short helical spring S is attached to the cross piece N and to a cross bolt or pin J in the casing and these springs normally hold the locking levers K in the position shown in Fig. 1.

The pull on the hoisting rope when lifting the load is in the direction of the arrow Fig. 1 and the rope easily passes under the shoes, which give under the strain. As soon as the hoisting rope is slackened or released the load pulls it in the inverse direction of the arrow on both sheaves and the rope is instantly jammed between the sheave and the riffled groove part Q of the shoe and thus checked and locked instantly and automatically on both sheaves. If the load is to be lowered the levers K are brought into the position shown in Fig. 3 by pulling on the rope connected with the link 0 whereby the springs S are brought in greater tension and as soon as the rope connected with said 'levers is released the springs S instantly throw the levers K into the position shown in Fig. 1 and then look the hoisting rope. \Vhen the levers K are in the position shown in Fig. 3 the hoisting rope passes through the smooth grooved part B which does not interfere with the free movement of the hoisting rope in either direction. When the load descends too rapidly but is not to be checked entirely but only its speed of descent reduced the outer ends of the levers K are pulled down a trifle more so that the smooth grooved part B acts as a friction brake shoe, thus retarding the speed of movement of the hoisting rope under the action of the descending load. As the brake shoes act on the rope on both sheaves, but a slight pull on the check rope is suflicient to retard the speed of descent.

Having described my invention what I claim as new and desire to secure by Letters Patent is 1. In a pulley block, the combination with a casing, of a sheave mounted therein, a brake lever pivoted above the sheave and provided with a shoe at one end, said shoe being provided with a curved cam groove provided with riftles, and with a smooth curved groove at the inner end of the curved rifiled groove and extending lengthwise of the lever, and a spring connected to the easing and to the lever for normally pressing the riflled groove upon the rope on the brake levers being united, substantially as sheave, substantially as set forth. set forth.

2. In a pulley block, the combination with Signed at New York city in the county of a casing, of two sheaves side by side, a brake New York and State of New York this 14th 5'lever pivoted above each sheave each brake day of May A. D. 1907.

lever having a shoe provided with a curved A I y I riffied groove extending to the end of the VILLTAM shoe and with a small grooved smooth part Witnesses:

at the inner end of the rifiled part extending DAVID C. THYTE,

10 lengthwise of the lever the outerends of said l OSCAR F. G'UNZ.