Anti-tip blocking device

A safety lock system for use in vertically stacked slidably retained storage elements for preventing the opening of more than one element at a time, said system comprising:

• a plurality of locking bars and a plurality of cam elements being vertically slidable in a vertical support guide means alternately stacked in vertical alignment one upon the other for limited vertical displacement therein defined by said vertical support guide means;
• each cam element having a cylindrical bearing surface to contact said vertical support guide means so that the cam element is vertically slidably retained by the guide means while rotatable about the axis of said cylindrical bearing surface between:
• (i) a first neutral position in which first cam portions of the cam element space opposed ends of adjacent locking bars alternating therewith by a first displacement distance, and
• (ii) a second extended position in which second cam portions of the cam element space opposed ends of said adjacent locking bars by a second displacement distance a predetermined distance greater than said first displacement distance;
• said limited vertical displacement and said predetermined distance being selected so that only one cam element can be in an extended position at any one time;
• an engaging member coupled to each of said storage elements to engage and displace an activating arm portion of an associated cam element rotating said cam element between its neutral and extended positions by displacement of the storage element between closed and open positions thereof,
• wherein with all of said storage elements carrying engaging members being in a closed position and with said cam elements being in a neutral position, upon at least partial opening of one storage element, the engaging member coupled thereto engages and displaces an activating arm portion of an associated cam element rotating the associated cam element to its extended position preventing the remaining cam elements from rotation to extended positions whereby respective actuating arm portions of the remaining cam elements upon engagement by engaging elements block opening of remaining storage elements carrying engaging elements.