A coupler for attaching a work attachment to a work vehicle is disclosed. The coupler includes a body, a jaw (6), an actuator to move the jaw along a path of movement so as to engage the pin (36B) of a work attachment, and thereby secure the work attachment to the coupler, and a locking mechanism (25) adapted to secure the jaw with respect to the work attachment at different positions along its path of movement. The actuator is connected to the locking mechanism so that only deliberate movement of the actuator moves the locking mechanism to a release position. This feature prevents the inadvertent release of the work attachment if the actuator fails.
