Patent ID: 7677291

Claim:
An engaging device comprising: a first member having a first engaging component with a first engaging surface, and a second member having a second engaging component with a second engaging surface capable of facing the first engaging surface, the first and second engaging components being capable of taking an engaging position in which the first and second engaging surfaces face each other and an open position in which the first and second engaging surfaces are spaced apart from each other, switchably through a relatively retracting action to retract the first and second engaging components relative to each other temporarily; a chamfered guide edge formed on the first engaging component in such a manner as to increase a width of the first engaging surface gradually as the guide edge extends from a first end side thereof to an opposite second end side thereof; a sliding contact edge formed on the second engaging component to extend obliquely relative to the guide edge and capable of abutting against the guide edge; and position control means configured to press the sliding contact edge against the guide edge gradually from the first end side of the guide edge toward the opposite second end side of the guide edge when an external force is exerted to move the engaging components from the engaging position toward the open position; wherein the first member is formed with a ridge serving as the first engaging component, the ridge having one surface serving as the first engaging surface and a protruding edge formed with the guide edge, wherein a first chamfered retraction guide surface is formed between the surface opposite the first engaging surface and the protruding edge; the second member is formed with a ridge serving as the second engaging component, the ridge having one surface serving as the second engaging surface and a protruding edge formed with the sliding contact edge; wherein a second chamfered retraction guide surface is formed between the surface opposite the second engaging surface and the protruding edge, wherein the second retraction guide surface is capable of abutting against the first retraction guide surface; and when an external force is exerted to move the first and second engaging components from the engaging position toward the open position, the relatively retracting action is performed.