| 摘要 |
<p>A safety mechanism to prevent unintended ejection of a staple or fastener in a stapler or fastening tool. A low-start version of the stapler has a handle that when pressed pivots a lever which lifts a striker and energizes a power spring. At the release point, the striker is released and accelerated under spring bias into a staple, ejecting the staple by impact blow. A high-start version has the striker stationary in the upper position as the power spring is energized. In the safety mechanism, a movable hook or arm selectively prevents the striker, and linked components thereto, from completing an operational cycle. In one embodiment the safety mechanism includes a working surface sensing button bar operating in conjunction with the hook that latches the striker. The safety mechanism can also be a pivoting lock bar that engages the working surface, which surface pivots the lock bar into engaging the power spring, handle, and/or striker thereby preventing such components from reaching the release point.</p> |
