| 摘要 |
An improved jack comprising a lead screw having a driven end and an upstanding integral boss proximate the driven end, the driven end comprising a body abutting the upstanding boss and including an opening therethrough for receiving the end of the lead screw, the body carrying slots, grooves or recesses radiating from the opening and being in communication with the opening and carrying material from the lead screw displaced into the grooves thereby securing the body to the lead screw. |
