Arrangement to obtain equal travel of hydraulic cylinders

Claim 1

An arrangement to obtain an equal travel of hydraulic cylinders in a hydraulic car lift having at least two single acting lifting cylinders powered by a common pressure source and with which a lifting platform is moved, is maintained in a substantially horizontal position by means of a leveling arrangement, and both cylinders being connected to a control arrangement which itself is controlled by the leveling arrangement which is influenced by the position of the platform, wherein the control arrangement is formed by two control valve members which are rigidly interconnected and controlled by the leveling arrangement, wherein one of the control members forms an upward control member which only controls the upward movement of the platform and the other control member forming downward control member only controlling the downward movement, the upward control member being connected to the pressure pump and the downward control member being connected to a discharge valve, said upward control member being respectively connected to said cylinders by a pair of pipelines and said downward control member being respectively connected to said cylinders by a second pair of pipelines, and wherein a pair of non-return valves are respectively inserted in the two pipelines from the upward control member to the corresponding cylinders which open in the direction towards the cylinders and a second pair of non-return valves are respectively inserted in the two pipelines from the downward control member to the corresponding cylinders which open in the direction towards the downward control member.