| 摘要 |
A compressed air pump comprising a compressed air piston motor (11) having a cylinder housing (12) and a low pressure piston (22) moveable between first and second end wall parts (13, 14) and a hydraulic piston pump (15) in the second end wall part (14). One side of the low pressure piston and the first end wall part together define a working chamber (21) and the other side of the piston (22) abuts and drives the hydraulic piston (24). A pilot piston (25), which is controlled by the low pressure piston (22) controls the supply of compressed air to the working chamber (21). A spring powers the return stroke of the low pressure piston and the hydraulic piston. The pilot piston (25) is housed in a pilot cylinder (35) incorporated in the first end wall part (13) and is mounted for movement between a first position and a second position. In the first position compressed air can be passed from an inlet (17) in the end wall part to the working chamber. In the second position the supply of compressed air is interrupted and an outlet opening (31) located between the working chamber (21) and an outlet (32) is opened so that return air can be evacuated. The pilot piston (25) has mounted therein a control piston (26) which is connected to the low pressure piston (22) and which controls the pilot piston to cause it to move from the first to the second position by opening a compressed air connection (41) to the pilot piston's working chamber (36).
|
