| 摘要 |
A chuck key as a tubular body extending along an axis and having an axially forwardly directed end formed with an array of teeth centered on the axis. A crosspiece extends diametrically through the body at the end opposite its toothed end. A pin is displaceable axially in the bore of the body between a front position projecting axially forwardly from the body beyond the teeth and in a rear position withdrawn axially backwardly in the body. A spring braced between the pin and the body urges the pin into the front position. An operating member is movable radially relative to the body and has an outer end that projects radially from the body. Interengaging formations on this member and on the pin displace the pin against the force of the spring from the rear to front position on depression of the end of the member radially inwardly. Thus the thumb of the hand grasping the crosspiece can push in the operating member to extend the pin for fitting of the key to a chuck. When the operating member is released the pin automatically retracts to ensure that the key disengages from the chuck. |
