Pneumatic cylinder apparatus

A cylinder apparatus comprising:

• a piston;
• a cylinder tube including a first end and a second end, the cylinder tube being formed to include a central bore extending from the first end to the second end for receiving the piston therein and a second bore extending from the first end to the second end spaced apart from the central bore;
• a first end cap coupled to the first end of the tube;
• a second end cap coupled to the second end of the tube, the second end cap being formed to include a first port in communication with the central bore of the tube and a second port in communication with the second bore;
• means for selectively coupling the first port to a pressure supply and the second port to an exhaust to move the piston in a first direction within the cylinder tube and for selectively coupling the second port to the pressure supply and the first port to the exhaust to move the piston in a second direction within the cylinder tube;
• a first seal location between the first end cap and the first end of the cylinder tube, the first seal permitting air blow between the central bore and the second bore adjacent the first end of the cylinder tube;
• and
• a second seal located between the second end cap and the second end of the cylinder tube, the second seal being configured to block air flow between the central bore and the second bore of the cylinder tube adjacent the second end of the cylinder tube;
• wherein said first and second seals have outer perimeters of substantially identical size and shape.

A cylinder apparatus comprising:

• a piston;
• a piston rod coupled to the piston;
• a cylinder tube including a first end and a second end, the cylinder tube being formed to include a central bore extending from the first end to the second end for receiving the piston therein and a second bore extending from the first end to the second end spaced apart from the central bore;
• an end cap coupled to the first end of the tube;
• a head cap coupled to the second end of the tube, said head and end caps being symmetrically formed and substantially similar in size and shape, the head cap being formed to include an aperture therein configured to receive the piston rod therethrough;
• means for moving the piston back and forth inside the central bore of the cylinder tube, the moving means including a first port in communication with the central bore of the tube and a second port in communication with the second bore, the first and second ports being formed selectively in one of the end cap and the head cap, the moving means also including means for selectively coupling the first port to a pressure supply and the second port to an exhaust to move the piston in a first direction within the cylinder tube and for selectively coupling the second port to the pressure supply and the first port to the exhaust to move the piston in a second direction within the cylinder tube.