FR2691449A1 - Moving counterweight for large crane - achieves equilibrium by rolling heavy cylinder on rails on rear boom to position calculated by computer for perfect balance - Google Patents

Abstract

The counterweight adjusts the crane equilibrium automatically by moving to and fro at the rear extension of the boom. The counterweight position may be determined by automatically calculating the load weight and its position on the front boom (d). This calculation may be instantaneous, by use of a computer. The counterweight may be a heavy cylinder, rolling on rails on boom rear, (B-C), controlled by cable and remote controlled motor. Equilibrium is perfect when moments balance either side of the centre support (f). USE/ADVANTAGE - Crane booms of tens of metres long. This device has better equilibrium, wind resistance and less wear, than fixed balance weights.

Description

 The present invention relates to a balancing regulator for large cranes.

Cranes of large dimensions, often have arrows measuring several tens of meters in length This notion of length, as well as that of height, is not
limiting, since smaller cranes, .- are also subject to the same problems, but with less acceptance. These problems have the names of imbalance, wind resistance and wear on the gears of the horizontal rotation racks.

 These arrows, on which the guide and lifting cables are generally controlled from a control cabin, pivot on a rack located at the top of the crane upright.

 The uprights are made up of four or more longitudinal members joined together by also metallic spacers and the assembly constitutes the "leg" of the crane, which rests on a metal support ptygone, which can be reinforced by masses of concrete. sometimes set is suitable for rolling on rails.

The "arm" of the crane, that is to say the boom and its rear extension, with concrete counterweights, is in perfect balance on the rack on which it pivots, only when the crane does not lift any material
This state of equilibrium is achieved by a counterweight formed by one or more concrete blocks fixed on the rear part, the front part being three, four or five times longer, without this proportion being limiting Whatever this proportion, the front part, in relation to the axis of rotation is much heavier hence the need for 1tXquilibre at the rear.

 The said * equilibrium state is always broken when the front boom is going to be used to lift and direct a heavy material, on a determined point of the site.

 The regulator, object of said patent is constituted by a mobile counterweight, which automatically flows from the point closest to the rack to the most distant point where the fixed counterweight is made of concrete.

If we call AB, the lifting boom and BC, the rear part with the counterweight, we can say that in operating art AB and BC are in perfect equilibrium at point F, that is to say, in the center of the rack (fig.I)
If we call d, the coefficient representing the distance of the lifting element and the distance to be covered by the mobile counterweight, the first being PM and the second PM ', we will therefore have: PM (d) equals PM '(d').

The object of the said invention can be achieved without the shape and dimensions being limiting, by a heavy cylinder, rolling on two rails at the rear, that is to say from B to C
The movement of such a mobile roller or counterweight is controlled by cable, motor and remote control.

The engine running and therefore the displacement of the mobile counterweight, in one direction or another, either towards
BC or CB, is analyzed by a mini-computer incorporated into the engine control system.

 When the crane takes charge of a material and as soon as the latter "takes off" from the ground, the mini-computer transmits the weight, analyzes the distance and permanently calculates the displacement of the mobile counterweight of the rear part.

 The weight of the material can be calculated and transmitted to the computer, by a known process or quite simply by the addition to the cabling system, of an additional bearing, recording the pressure on a pre-calibrated graduation (Fig. 2)

Claims (5)

 I-Device and equipment for automatic balancing of cranes and especially large cranes.  2-Device and apparatus according to claim I caractéri -séspar a mobile counterweight located at the rear of the boom of the crane  3-Device and apparatus characterized by the automation of the movement of the counterweight.  4-Device and apparatus according to claims I, 2 and 3 in that the calculation of the automation of the movement of the counterweight is transmitted by the weight of the load and its longitudinal displacement on the guide arrow.  5-Device and apparatus according to claims, I, 2,3 and 4 in that the weight and the distance of the movement of the counterweight are calculated instantly and permanently by a conventional computer.