Abstract: A rear end hook structure (44, 46) on a coupler (10) presents rearwardly directed hook throats (48, 50) which engage a rear coupler pin (96) on a attachment (94). An initially downwardly angled front end hook structure (52), presenting a forwardly directed hook throat (54), is movable by movement of a coupler (10) to move a forward coupler pin (96) on the attachment (94) into the hook throat (54). Then, the coupler (10) is moved further to swing the front end hook structure (52) upwardly into an up position in which it is against a bottom plate (40) on the coupler (10). Movement of the front end coupler structure (52) into its up position moves a hook tine (60) upwardly through a slot opening (62) in the bottom plate (40) of the coupler (10). The hook tines (60) moves upwardly until its rearwardly directed hook throat (78) is positioned to receive a lock member (66, 116, 180). Then, a spring (84, 190, 192) moves the lock member (66, 116, 180) into the hook throat (54).