An accelerator-equipped pneumatic cylinder, comprising:
- a cylinder block, having a piston chamber and a pressure chamber;
- a switch valve, having a valve seat installed in the cylinder block and between the piston chamber and the pressure chamber, the valve seat having a channel and receiving a controller that makes the piston chamber and the pressure chamber communicated with each other or not by opening or closing the channel;
- and
- a pneumatic cylinder, having a piston portion receiving in the piston chamber, and having a shaft portion extending outward from one side of the piston portion to be exposed outside the cylinder block, so that when the channel is closed by the controller and the piston chamber and the pressure chamber are not communicated with each other, a pressure medium supplied into the pressure chamber by a pressure source is accumulated to a predetermined pressure level, and at a moment when the channel is opened by the controller and the piston chamber and the pressure chamber come into communication with each other, the piston portion is pushed by the pressure medium at the predetermined pressure level, so that the shaft portion is pushed out the piston chamber at an accelerated speed;
- wherein,
- the controller is a valve stem, and the valve stem is received in the valve seat in an axially movable manner and passes through the channel, in which the valve stem has a small-diameter segment with a reduced diameter, and the small-diameter segment is positionally aligned with the channel, the valve stem having one end with the small-diameter segment provided with a front retaining ring, so that when the valve stem axially moves in the valve seat to make the front retaining ring enter the channel, the channel is closed, and when the front retaining ring is retracted from the channel, the small-diameter segment allows the channel to become open;
- and
- the valve seat defines therein an operation chamber, whose two ends provided with a first runner and a second runner, respectively, to communicate with the outside of the valve seat, in which the valve stem has one end provided with a drive portion that is received in the operation chamber, so that the pressure source is configured to enter the operation chamber through the first runner and to push the drive portion and then drive the valve stem to axially move to make the front retaining ring enter the channel so as to close the channel, and the pressure source is also configured to enter the operation chamber through the second runner to reversely push the drive portion and then drive the valve stem to axially move to retract the front retaining ring from the channel so as to open the channel.