Direction-switchable pneumatic cylinder

A direction-switchable pneumatic cylinder comprising:

• a cylinder body having an internal cylinder chamber;
• a first and a second intakes being formed on a front end of the cylinder body;
• several exhaustion ports being formed on a rear end of the cylinder body;
• a switch seat fixed connected with the front end of the cylinder body;
• a cavity being formed in the switch seat;
• a gas inlet being formed on the switch seat to communicate with the cavity;
• a switch button airtight movably mounted in the cavity of the switch seat;
• a controlling member being connected with the switch button for driving the switch button to move between two positions;
• at least one gas conduit being formed on the switch button, the gas conduit having a rear end corresponding to the two intakes, whereby when the switch button is switched to one of the two positions, the rear end of the gas conduit communicates with the first intake, while when the switch button is switched to the other position, the rear end of the gas conduit communicates with the second intake;
• a rotary shaft rotatably arranged in the cylinder body;
• and
• a predetermined number of movable wheels and fixed wheels, each the movable wheel being formed with several vents concentrically arranged into an inner circle and an outer circle, a direction of the axis of the vent of the inner circle being different from a direction of the axis of the vent of the outer circle;
• each the fixed wheel being formed with several vents concentrically arranged into an inner circle and an outer circle, a direction of the axis of the vent of the inner circle of the fixed wheel being different from a direction of the axis of the vent of the outer circle of the fixed wheel;
• the direction of the axis of the vent of the outer circle of the fixed wheel being different from the direction of the axis of the vent of the outer circle of the movable wheel;
• the direction of the axis of the vent of the inner circle of the fixed wheel being different from the direction of the axis of the vent of the inner circle of the movable wheel;
• the fixed wheels and the movable wheels being arranged in the cylinder chamber along the axis of the pneumatic cylinder and interlaced with each other;
• the rotary shaft being fitted through the fixed wheels and movable wheels;
• the fixed wheels being fixedly mounted in the cylinder chamber without rotation;
• the movable wheels being fitted around the rotary shaft and synchronously rotatable therewith;
• the vents of outer circles of the fixed wheels and the movable wheels being aligned with each other and communicating with the first intake;
• the vents of inner circles of the fixed wheels and the movable wheels being aligned with each other and communicating with the second intake.