Abstract: Apparatus for detachably coupling two objects together including a pair of coupling blocks relatively movable between remote, inoperative positions, and adjacent, coupling positions. A locking tongue projects outwardly from one of the blocks and is received in a recess provided in the other of the blocks. A locking pin, mounted on the other of the blocks, is provided for movement thereon between a position in which the blocks may be moved toward and away from each other, and another position in which a portion of the locking pin bears against the tongue to urge the blocks toward each other.