Abstract: A cold start valve for a hydraulic circuit has a valve slide with two counteracting control faces. It is possible to load a first control face with a control pressure and to load a second control face with a feed pressure. In addition, the first control face is loaded with the spring force of a valve spring. A damping space is configured to damp a stroke movement of the valve slide. The damping space is delimited by a damping face formed on the valve slide and oriented in accordance with the first control face. The damping face is configured to be loaded via the damping space with a damping pressure to damp the stroke movement. The damping space is connected in a throttled manner to a pressure space. The second control face of the valve slide is configured to be loaded with the feed pressure via the pressure space.

Abstract: A cold start valve for a hydraulic circuit has a valve slide with two counteracting control faces. It is possible to load a first control face with a control pressure and to load a second control face with a feed pressure. In addition, the first control face is loaded with the spring force of a valve spring. A damping space is configured to damp a stroke movement of the valve slide. The damping space is delimited by a damping face formed on the valve slide and oriented in accordance with the first control face. The damping face is configured to be loaded via the damping space with a damping pressure to damp the stroke movement. The damping space is connected in a throttled manner to a pressure space. The second control face of the valve slide is configured to be loaded with the feed pressure via the pressure space.

Abstract: A control device for a hydrostatic gear driven by a drive engine, preferably an internal-combustion engine, is described, having an auxiliary pump, which is driven synchronously with the drive engine speed, for the generation of a control pressure which may be adjusted by way of a regulating valve, which is dependent upon the speed of the drive engine and which acts upon the setting mechanism for the hydrostatic gear. A pressure reducing valve ("inch" valve) is thereby provided for the purpose of shutting off the control pressure as a function of an external parameter and also for lowering the control pressure in the case of a load speed reduction of the drive engine ("partial inch" function).

Abstract: A control device for a hydrostatic gear driven by a drive engine, such as an internal combustion engine, with an auxiliary pump which is driven synchronously with the drive engine, to produce a control pressure which is adjustable via a control valve and which is dependent on the speed of the drive engine. The control device also has further a pressure reduction valve located in the control line, to remove or shut off the control pressure depending upon an external parameter. In order to make possible, with such a control device, both a partial pressure reduction and a complete pressure reduction by hydraulic means without the aid of sensitive control rods, it is proposed in this invention that the pressure reduction valve have a servo valve spool which is adjusted by the external parameter.