By-pass incorporated in hydraulic control and activation cylinders to facilitate air bleeding

A hydraulic control arrangement comprising:

• a hydraulic driving pump including a tank and vent;
• at least one operation cylinder to facilitate air bleeding and purging in a hydraulic circuit, each said cylinder including:
• an external jacket,
• cylinder heads at opposite ends of the jacket,
• a piston movable in said jacket,
• right and left drive rods connected with opposite sides, respectively, of the piston and protruding from the cylinder heads,
• left and right cylinder chambers in said jacket on opposite sides of said piston,
• a by-pass in the jacket of the cylinder and which connects the left and right cylinder chambers of the cylinder, and
• an externally controlled opening and closing device associated with the by-pass;
• fluid coupling fittings at opposite ends of the jacket;
• pipes connected with the fluid coupling fittings and which independently connect the left and right cylinder chambers to the hydraulic driving pump;
• and
• a valve arrangement fluidly connected between the pipes and the hydraulic driving pump to speed up and simplify hydraulic fluid feed and air purging operations of the left and right cylinder chambers.