Hydraulic control device for vehicles with a pivotable working implement

摘要

A hydraulic control device for a working vehicle comprises a pivot motor (36), which can be driven in opposite directions, for pivoting or rotating the superstructure of the vehicle. The pivot motor is provided with a single-acting brake cylinder (44) which is prestressed by a spring (196), and is braked by means of the latter normally under the force of the spring (196). The pivot motor (36) is enabled if the brake cylinder (44) is supplied with pressure medium. The pivot motor (36) is controlled by a pivot valve (52) which is pilot-controlled itself by means of a manually activated pivot control valve (114). So that the pivot motor cannot be actuated accidentally whilst the brake is active, a brake valve (200) is provided which prevents the pilot control of the pivot valve (52) by the control valve (114) as long as the brake cylinder (44) acts on the pivot motor (36) under the force of the spring (196). The pivot pilot-control valve (114) can only then act on the pivot valve (52), so that the superstructure of the vehicle can be rotated with the aid of the pivot motor (36), when the brake valve (200) is actuated by actuating an on/off switch (212) with the aid of an exciter coil (208) so that the brake cylinder (44) is supplied with pressure medium and enables the pivot motor. <IMAGE>