| 摘要 |
<p>The apparatus for punching holes in a work member includes a weight-balanced frame member having supported thereon opposed punching die and a matrix. The frame is initially moved vertically to properly position the matrix and die relative to the member to be punched. Located adjacent the matrix are sensing elements that are positioned to be contacted by the member to be punched, which sensing elements, when contacted stop the vertical movement of the frame. This arrangement substantially reduces the pivotal movement of the frame member which occurs during the punching operation and thus greatly minimizes the movement of the balancing weight that is mounted on a lever to maintain the frame in the balanced position free of contact with the member to be punched and thus avoids any substantial acceleration of the weight member which could adversely affect the punching operation.</p> |
