Safety bolt

A safety bolt comprising:

• an element having a shank with an axis, the element having a first end and a second end, an axial passage opening onto one of said ends, and a laterally-extending passage in the shank and intersecting the axial passage;
• a dog in said laterally-extending passage slidably movable between an extending and a retracted position, whereby the dog extends beyond the maximum diameter of the shank in the extended position and retracts entirely within said shank in the retracted position, thereby being adapted to abut the back side of a workpiece into which the shank is inserted;
• a cam member axially movable in said axial passage and reactive with said dog to retract or to extend the same, said cam member having a pair of sloping cam surfaces which face in opposite lateral directions;
• a pair of oppositely facing spaced-apart follower surfaces on said dog, each said follower surface being parallel to and engaging a respective one of said cam surfaces in substantial surface-to-surface contact, whereby one set of said cam surfaces and follower surfaces causes movement of the dog in one direction of movement of the cam member and the other set causes movement of the dog in the other direction of movement of the cam member, said sets being in embracing relationship, whereby the lateral position of the dog is a unique function of the axial location of the cam member in the axial passage;
• and bias means biasing the cam member in its direction which forces the dog toward its extended position, the dog when extended when the shank is fully inserted in the workpiece preventing the removal of the bolt from the workpiece.