| 摘要 |
<p>A rotatable crank hub has a crank arm slot pivotally connected to the rearward ends of a pair of driving levers, the forward ends of the driving levers being pivotally connected to a longitudinally slideable bolt. Rotation of the crank hub in opposite directions moves the bolt through the crank arm and driving levers forwardly to bolt extended position and rearwardly to bolt retracted position during which a transverse driving pin between the crank arm and driving lever rearward ends moves into forward vertical slots of the latch frame in the bolt extended position and into rearward vertical slots of the latch frame in bolt retracted position. A cam projection on the crank hub is slideably resiliently engaged at one side approaching and in bolt extended position and the other side approaching and in bolt retracted position by a forward leg of a U-shaped spring, a spring rearward leg being engaged with the latch frame. Thus, the bolt is positively retained in extended and retracted positions by the resilient urging of the driving pin into the forward and rearward frame slots and the spring engagements with the cam projection are preferably formed such that the driving pin is continuously resiliently urged into either of the forward or rearward slots even after positioning in such slots. Also, the forward frame slots may be formed hook-shaped for more positively retaining the driving pin therein once positioned therein.</p> |
