| 摘要 |
The percussion device which can be used as a hammer drill has a drive piston for driving an overhung percussion piston which is mounted between two air cushions. Depending on the percussion travel of the percussion piston, the percussion air cushion is reversed so that a respective partial quantity is passed around the percussion piston to the opposite side by a central bypass. A no-load bypass is also provided to vent the recoil air cushion to the percussion cushion for a no-load condition. A third bypass bridges the drive piston in the top dead center position to communicate an annular chamber to the rear of the drive piston with the percussion cushion.
|
