Device for reducing piston velocity in a cylinder

In piston and cylinder assemblies, a device for reducing the piston velocity as the piston approaches the end positions, comprising:

• a cylinder,
• a piston reciprocating in the cylinder and connected to a part to be driven by the piston and cylinder assembly,
• a signal transmitter adapted to sense the position of said part,
• a valve means for controlling a fluid supply to said cylinder,
• an actuator means which is adapted to produce a positive or negative signal to lengthen and shorten, respectively the piston and cylinder assembly at a velocity dependent upon the position of setting of said actuator means, a control unit which is connected to said signal transmitter and said actuator means, said signal from said actuator means being applied to said control unit and compared therein with a signal from said position sensing signal transmitter such that if the positional signal has a value between a predetermined minimum value and a predetermined maximum value, said control unit emits a hydraulic fluid supply controlling signal to said valve means which is directly proportional to the setting of said actuator means, but if the positional signal has a value below or above said predetermined minimum or maximum values, respectively, said control unit emits a hydraulic fluid supply controlling signal which reduces the hydraulic fluid supply so as to become a directly linear function of the distances of the piston to its respective end position if the signal of said actuator means is negative and the positional signal has a value below the minimum value or if the actuator means signal is positive and the positional signal has a value above the maximum value, but which is directly proportional to the setting of the actuator means when the signal of the actuator means is negative and the positional signal has a value above the maximum value or it positive and the positional signal has a value below the minimum value.