The locking device for automatically locking a movable closure member relative to a stationary member such as a vending machine door and cabinet respectively, comprising;
- a lock mechanism of the type provided with a lock stud having a horizontal axis mounted on the movable closure member, said lock stud having an anterior end and a posterior end, and having a lock handle secured thereto at the anterior end, and the posterior end formed into a nose portion,
- said lock stud provided with a series of male threads formed in said lock stud adjacent to and along the posterior end thereof and provided with disengagable lock engaging means formed in said lock stud posteriorly of said male threads and anteriorly of said nose portion,
- stud receiving locking means mounted on the stationary member,
- said stud receiving locking means formed by a housing which accommodates the insertion therethrough of said lock stud, said housing including a first rotatable tubular sleeve member having an anterior end and a posterior end and having a reduced diametric interior adjacent the anterior end and an expanded diametric interior adjacent the posterior end thereof,
- said posterior end having at least one cammed surface formed along the posterior surface thereof,
- a tubular coupling member having an anterior end and a posterior end and seated within said first rotatable tubular sleeve member, said coupling member having a reduced diametric throat portion adjacent the anterior end thereof and a larger diametric throat portion adjacent the posterior end thereof,
- said reduced diametric throat portion having at least one aperture formed therein and said larger diametric throat portion provided with disengagable lock means carried thereon,
- at least one radially curved grasping element seated within the confines of said aperture in said reduced diametric throat portion of said coupling,
- said coupling member seated within said first rotatable tubular sleeve member such that said reduced diametric throat portion thereof is positioned in radial alignment with said reduced diametric anterior end of said first rotatable tubular sleeve member, and said larger diametric throat portion is in radial alignment with said expanded diametric throat portion of said first rotatable tubular sleeve member when said respective members are in the rest position,
- a second stationary tubular sleeve member seated adjacent said first rotatable tubular sleeve member and in horizontal alignment therewith adjacent the posterior end thereof, having an inner lip end and an upper spring seat surface,
- said second stationary tubular sleeve member having at least one stationary cam surface formed along said inner lip end for cammingly engaging said cammed surface formed along the posterior end of said first rotatable tubular sleeve member,
- said second stationary tubular sleeve member being stationary relative to said housing and said first rotatable tubular sleeve member being rotatable relative to said second tubular sleeve member along the cam surfaces thereof,
- biasing means interposed between said first rotatable tubular sleeve member and said housing, and coupling biasing means interposed between said coupling and said upper spring seat surface of said second stationary tubular sleeve member such that said first and second tubular sleeve members are normally biasingly urged together and said coupling is normally biasingly urged away from said second tubular sleeve member,
- said first rotatable sleeve member, coupling and second stationary tubular sleeve member being adapted to accommodate the insertion therethrough of said lock stud,
- whereby upon insertion of said lock stud into said housing, said male threads thereof will confront said radially curved grasping element carried by said coupling and biasingly urge said coupling posteriorly until said radially curved grasping element is permitted to reciprocate upwardly through said aperture containing same when said reduced throat portion of said coupling is in registry and alignment with said expanded diametric interior of said first tubular sleeve member, and allows said radially curved grasping element to ride into one of the male threads of said lock stud such that upon release of said lock stud, said grasping element retracts once again into said aperture when entering said reduced diametric anterior of said first tubular sleeve member thereby to lock said lock stud within said housing;
- and the opening of the lock mechanism is accomplished by rotating said lock stud counterclockwise until said disengagable lock engaging means engage the disengagable lock means carried in the posterior end of said coupling thereby to permit rotation only in a counterclockwise direction and thereby to permit only the rotation of said first tubular sleeve member to cam anteriorly relative to said second tubular sleeve member until the radially curved grasping element rides into the expanded throat portion thereof and out of contact with said male threads of said lock stud permitting said lock stud to be fully withdrawn from said lock stud receiving mechanism and allow opening of the movable closure member relative to the stationary member.