EP0192750A1 - Hydraulic rotates system for swing crane. - Google Patents

Abstract

Un système hydraulique de rotation pour une grue pivotante comprend essentiellement un moteur hydraulique (A), un mélangeur (B), une soupape à deux voies (C) et une soupape de direction (D). Le mélangeur (B) libère de l'huile lorsque le circuit d'alimentation de la grue est interrompu et permet à la flèche de la grue de se placer elle-même automatiquement dans la direction du vent. En fonctionnement normal, l'effet de régulation du mélangeur (B) peut être éliminé, si on le désire, par l'intermédiaire de la soupape (C) qui est commandée à partir de l'organe de manoeuvre dans le cas d'une immobilisation par arrêt ou démarrage puissant du mouvemnt rotatif.A hydraulic rotation system for a pivoting crane essentially comprises a hydraulic motor (A), a mixer (B), a two-way valve (C) and a directional valve (D). The mixer (B) releases oil when the crane supply circuit is interrupted and allows the crane boom to automatically position itself in the direction of the wind. In normal operation, the regulating effect of the mixer (B) can be eliminated, if desired, by means of the valve (C) which is controlled from the operating member in the case of a immobilization by stopping or powerful starting of the rotary movement.

Description

Hydraulic Rotate System for Swing Crane.

The invention concerns a hydraulic rotate system, in which a shunt is laid across the supply gate of the hydraulic motor.

Normally swing cranes are provided with a boom, by which both a great rotation - inertial factor and an eccentric wind attack area are produced. By swing cra¬ nes for the building industry the crane shall, when it is going to be left, be able to swing freely in the wind. As by these types of cranes exist a demand for the so-called principle of "dead man", where all mo¬ vements are to be stopped, when the signals of activa¬ tion or the electric current supply do not take place, it is for free position demanded a manual operation with the rotate system, a matter which in many cases is for¬ gotten with damages as a result.

By the present construction, as per the invention, it is taken care that the crane by fail of circuit can rotate away from the wind, although with controlled speed.

Because of its characterization, which consists in in¬ creasing ability of braking on on increasing speed, the invented system also prevents the situations, where the crane starts to rotate uncontrolled, when about the half of the working area of the crane is laying under cover from the wind.

By normal operation of the crane it is through manoeuv¬ ring organs possible to cancel the shunt effect, if either greater power on machinery is wanted or it is wanted to get the motor function as standstill brake. 2 .

The invention will in the following be described with references to the drawing, as

Fig. 1 shows a schematic outline of the invention in unactivated situation.

5 Fig. 1 shows a schematic outline, as per the invention, seen in unactivated circuit loose situation, where the hydraulic motor A can circulate oil through a two-ways valve C and a blend B, when the crane is to be able to place itself in the direction of the wind.

10 In function a steering valve D is activated to start the rotate movement, according to, if all the oil are wan-^" ted to the motor A on powerful start or more mild start with pressure- and flow reduction through blend B, the valve C respectivelycan be activated or stay in the

15 shown position.

Claims

C L A I M S,

1. Hydraulic rotate system for swing crane c h a r a c- t e r i z e d by that means that it by fail of circuit allows the crane to place itself in the direction of the wind, as the hydraulic motor (A) can circulate oil through a blend (B).

2. Hydraulic rotate system for swing crane, as per claim 1, c h a r a c t e r i z e d by that means that the shunt effect can be cancelled by help of the valve (C) to e- stablish brake function or more powerful start.