Control device for a working device connected to a hydraulic circuit

Abstract

A control device for a working device (12) connected to a hydraulic circuit (10), especially for a load fork (16) which can be raised and lowered with a working cylinder (14) in a fork-lift truck. A valve control unit moves into an adjustment position when the load fork (16) is lowered even when carrying a load (18). A predefinable maximum volume flow is maintained in the hydraulic circuit (10). By providing the valve control unit with a pressure regulator (26) limiting a pilot control pressure for the control valve (28), once a predefinable regulating pressure differential is reached in the hydraulic circuit, the control valve moves into a regulating position to maintain the maximum volume flow. The known flow control valve is replaced in the main flow by a pressure regulator (26) disposed in the pilot control circuit (40), and only needs to be dimensioned for low volume flows. As a result, the control system can be constructed using simple, low-cost components which operate in a functionally reliable manner and enable stable control behavior.

Dependencies are inferred from the claim text.