the wing lock is a safety mechanism for a snow plow blade and is engaged when the plow blade is not in use . the safety mechanism is primarily a pin and tongue assembly which is actuated by an air , electric , or hydraulic cylinder tied to the truck on which the plow is mounted . the pin is protected by a collar and sleeve which are disposed below the actuator cylinder . the tongue is affixed on the support arm of the plow wing so that when the support arm is raised the tongue slides into a receiving position for the pin . the pin drops through the tongue to lock the blade . for use , the safety mechanism is activated or deactivated from the truck cabin by a lighted , electrical switch which sends a signal to the actuator to deploy or retract the pin so that the plow may be locked or unlocked .