US3306469A

US3306469A - Load hoisting tackle

Info

Publication number: US3306469A
Authority: US
Inventors: Durand Pierre
Original assignee: Richier SA
Current assignee: Richier SA
Priority date: 1965-06-22
Filing date: 1965-10-24
Publication date: 1967-02-28
Anticipated expiration: 1984-02-28
Also published as: FR1451362A; NL6608577A; CH431868A; GB1084005A; DE1285152B

Description

Feb. 28, 1967 v P. DURAND 3,

LOAD HOISTINGQTACKLE Filed Oct. 24, 1965 2 Sheets-Sheet 1 I INVENTOR 1 /5695 fi k M BY ATTORNEYS Feb. 28, 1967 P. bURAND 3,306,469 LOAD HOISTING TACKLE Filed Oct. 24, 1965 2 Sheets-Sheet 2 INVENTOR P/fgk: Amen/ 0 BY ATTORNEYS United States Patent Ofifice 3,306,469 Patented Feb. 28, 1967 4 1 Claim. for. 212 71 My invention relates generally speaking to a tackle system similar to those used for hoisting loads, more particularly in the case of tower cranes and the like appliances.

On such apparatus, the loads are generally hoisted by means of tackles having a variable number of strands, generally two or four strands, so as to allow the operator to modify the hoisting force or speed. Generally such a change in the number of the strands is performed as illustrated in FIGS. 1 and 2 of the accompanying drawings by means of a pulley P adapted to occupy two positions for one of which (FIG. 1) said pulley engages the main tackle which corresponds to the case of a two-stranded tackle, while the other position (FIG. 2) corresponds to a securing of said pulley to the carriage C and consequently to a four-stranded tackle.

The passage from one position to the other is obtained by setting the carriage C at a suitable point of the jib of the crane, after which the pulley block is brought into contact with the carriage C and means are operated for the engagement or for the release of a pulley P as the case may be. Said means are usually actuated starting from the operators cab through the agency of a mechanical control system and when the crane is no longer controlled from said cab, but say from ground or from some building through an electric remote control system, the operator is constrained to return into his cab so as to produce the desired change in the tackle and this increases the intricacy of the operation and leads obviously to a substantial loss of time.

My invention cuts out these drawbacks and allows ensuring said change in the tackle by means of an arrangement carried by said tackle and adapted to be controlled by a remote control system so as to be brought near an operator located at any desired point.

It has consequently for its object a tackle system wherein the carriage for the upper pulley is provided with a componud transverse strap of which the flanges or sides are pivotally secured around two parallel spindles lying in their plans and are subjected to an elastic force which urges them towards each other, said flanges defining thus together a downwardly flaring opening while the main pulley block is equipped with two symmetrical sloping members pivotally carried by transverse spindles so that they may occupy two positions for one of which they are adapted to engage the gap between the flanges of the strap and for the other of which they lie outside the latter; furthermore, an axially pulley block carries a transverse pin adapted to be raised and to engage said strap so as to allow duplication of the number of operative strands.

My invention will be readily understood together with its advantages and further features from a reading of the following description, reference being made to the accompanying drawing illustrating by way of example'and in a non-limiting sense a preferred embodiment of my invention as applied to a hoisting apparauts incorporating a strand-distributing carriage and tackle operating selectively with two and four strands. In said drawings:

FIGS. 1 and 2 refer to prior art as already disclosed;

FIG. 3 is a side view of the system including the carriage and the tackle in its two-stranded condition;

FIGS. 4, 5 and 6 are front elevational views of the strap fitted on the carriage and of the pulley blocks shown respectively for two stranded conditions of the tackle and for its four-stranded condition and during the pas: sage between the two conditions.

In FIG. 3, 2 designate the strand distributing carriage which carries in accordance with my invention two parallel transverse spindles 3 to which are pivotally secured two levers 4 interconnected by a spring urging them against the stop 6. Said levers 4 are provided with perforations 7 registering with each other and form together a sort of strap the opening of which flares downwardly, as shown at 8, said flaring being obtained by a bending of the outer ends of the levers 4 away from each other.

The main or lower pulley block includes two parallel sloping members pivotally carried by two coaxial transverse pivots 12. Said sloping members can occupy selectively two positions illustrated respectively in solid lines and in interrupted lines in FIG. 3.

As to the auxiliary pulley block 13, it carries above its pulley a transverse pin 14.

When the tackle operates with two strands as illustrated in FIGS. 3 and 4, the auxiliary pulley block 13 engages the main pulley block 9, while the sloping members 10 occupy the position illustrated in solid lines.

When it is desired to set the tackle in its four-stranded condition, it is suflicient to operate as follows: the tackle being laid on the ground with the sloping members 10 remaining in the solid line position illustrated in FIG. 3, the circuit defining the upper end of the stroke is closed by the operator at the control station; after which said operator provides for the raising of the tackle up to its uppermost position for which it engages the carriage 2. The pin 14 enters thus the gap between the two bent levers 4 which are urged apart thereby and compress the spring 15, said levers returning into their former position as soon as the pin 14 registers with and engages the perforations 7. The auxiliary pulley block is thus in contact with the carriage 2 as illustrated in FIG. 5. The main pulley block 9 is then allowed to sink, whereby the formation of a four-stranded tackle is obtained.

When it is desired subsequently to return to a twostranded condition, the main pulley block 9 is lowered again onto ground surface and its sloping members are returned into the position illustrated in interrupted lines in FIG. 3, the block being then raised in an empty condition up to the carriage 2. Under the action of the sloping members 10, which as illustrated in FIG. 6 engage the gap between the bent levers 4 and the auxiliary pulley 13, the compound strap formed by said levers opens and releases thus the auxiliary pulley block 13 which returns into its lower position on the main pulley block 9. The tackle is then lowered onto ground surface. The sloping members are returned into their normal outwardly directed position illustrated in solid lines in FIG. 3.

Obviously, my invention is not limited to the sole embodiment described and illustrated by way of example and it covers all the modifications thereof falling within the scope of the accompanying claim.

What I claim is:

A load-hoisting tackle chiefly for tower cranes and the like appliances comprising upper pulleys, a carriage carrying said upper pulleys, a compound strap including two downwardly flaring flanges separated by a gap and adapted to pivot away from each other round horizontal axes lying in their planes and perpendicular to the axes of the upper pulleys, elastic means urging the lower ends of the flanges towards each other, a main pulley block including at least one pulley and adapted to be connected selectively through two strands and four strands with the upper pulleys and two sloping members arranged symmetrically to either sides of a vertical plane perpendicular to the axis of the pulley of the main pulley block and adapted to rock each round a spindle parallel with last-mentioned axis between an outwardly directed inoperative position and an operative position for which said members are adapted to enter the gap between the flanges of the strap to urge said flanges apart and an auxiliary pulley block including a pin parallel with the pulley axes, said auxiliary pulley block resting normally on the main pulley block to allow the latter to be connected through two strands with 10 the upper pulleys and being adapted, upon raising between the flanges of the strap and urging the latter apart to snap into an upper position on the carriage to ensure a four-stranded connection with the main pulley block, the release of the auxiliary block being provided by the en- References Cited by the Examiner UNITED STATES PATENTS 840,676 1/1907 Winnard et al. 254188 1,436,608 11/1922 Rodier 254l88 2,973,942 3/1961 Sehaper 254188 FOREIGN PATENTS 171,531 10/1965 Russia.

ANDRES H. NIELSEN, Pnimary Examiner.