| 摘要 |
A percussion tools such as a pneumatic hammer, drill, concrete braker and the like in which a ram is pneumatically reciprocated in a cylinder to drive a tool, has a head provided with the handles gripped by the user and forming a pneumatic cushion with the cylinder. According to the invention, this head carrying the handles is mounted with slight clearance slidably on the cylinder and the pneumatic cushion is formed between the upper end of the cylinder and the interior of the head. A sleeve attached to the head and surrounding the cylinder communicates with the cylinder through the usual reciprocation-producing valve and a portion of the air pressure is bled through the clearance into the cushion. A vent passage of the cylinder communicates with the cushion chamber and can register with a passage in the sleeve opening into the atmosphere. |
