Locking device for interlocking nested shopping carts

A locking device for interlocking at least two nested shopping carts, said device comprising a housing having attachment means to immovably secure same at a predetermined location on a shopping cart handle, a coinactivated unlocking actuator movably mounted in said housing for displacement on a working axis, said actuator having coin-carrying means having at least one coin slot in a wall of said actuator, actuator spring biasing means to bias said actuator inwardly of said housing to position said coincarrying means and coin slot inside said housing, arresting means limiting inward displacement of said actuator along said working axis in the absence of at least one coin in said carrying means, a locking mechanism displaceably mounted inside said housing and having a lock pin and a lock pin displacing member, a key element receivable in a key slot in said housing and immovably engageable by said lock pin, and an actuator retention member having at least one retention element, one of which has a pin ejector associated therewith for engaging said actuator in said housing, said key element having at least two lock disengaging contact points in a free end of said key for disengaging said engaging means to thereby release said actuator and cause said locking mechanism to engage said key element in said housing, said contact points lying in two different planes and disposed to contact a respective one of said at least one retention element.