| 摘要 |
A hammer tool such as a rotary hammer, hammer drill or the like includes a motor housing and a gear case secured to the motor housing forwardly of the motor housing. A motor in the motor housing has a shaft projecting into the gear case and a pinion formed on the end of the motor shaft. A first set of ratcheting teeth is formed on a body rotatably journaled in the gear case. An output spindle for holding a tool bit is provided and has a longitudinal axis. The output spindle is rotatably journalled in the gear case so as to be also slideable in the direction of said longitudinal axis. A second set of ratcheting teeth is mounted on the output spindle so as to be in confronting relation to the first set of ratcheting teeth. A spring provides a resilient force for holding the first and second sets of ratcheting teeth in spaced apart relation to each other. A gear transmission is operatively connected to the pinion for simultaneously rotating the first set of ratcheting teeth at a predetermined first angular velocity and for rotating the second set of ratcheting teeth at a predetermined second angular velocity whereby one of the sets of ratcheting teeth ratchets over the other one of the sets of ratcheting teeth thereby imparting longitudinal impact blows to the output spindle when the first set of ratcheting teeth and the second set of ratcheting teeth mutually engage in response to an axial movement of the output spindle caused by the tool being pressed toward a work surface against the resilient force developed by the spring. |
