| 摘要 |
A pneumatically-actuated multi-needle type chisel tool is provided having a hollow cylinder body, a piston ram fitted for axially reciprocal movement in a rearward portion of the cylinder body, an anvil fitted for axially reciprocal movement in an intermediate portion of the cylinder body, a needle holder fitted for axially reciprocal movement in a forward portion of the cylinder body and a number of needle chisels journaled for axially reciprocal movement in the needle holder. A first air passage is provided with an opening into the rearward portion of the cylinder body to introduce compressed air thereinto for moving the piston ram to and fro. A second air passage is provided with an opening into the forward portion of the cylinder body to introduce compressed air thereinto for moving the needle holder rearwardly. A cylinder cap is axially adjustably mounted to the forward portion of the cylinder body with the rear end face of the cap facing opposite to the outer peripheral forwardly facing surface of the needle holder such that the air pressure in the space of the cylinder body interior enclosed by the anvil and the needle holder is pressurized upon the anvil being rapidly moved forward by the impact from the piston ram, causing the pressurized air force to move the needle holder forwardly. Similarly, the air introduced into the forward portion of the cylinder body in front of the outer peripheral forwardly facing surface of the needle holder is compressed during the forward movement of the needle holder. |
