Abstract: Apparatus for mounting equipment to a vehicle includes first and second frames adapted for sliding engagement between downwardly extending wing members of the top frame within grooves formed by bends along opposite edges of the bottom frame. A spring locking member attached to the bottom frame is received within an oblong hole in the upper frame in a locked and engaged position, to urge the wing members into engagement with the bent edges of the lower frame. The spring locking member is located within a slot in an upwardly extending portion of the lower frame to constrain it only to upward and downward movement. In the engaged position the locking member prevents movement in orthoginal or transverse directions thereby securing firmly the first and second frames and equipment carried thereby to the vehicle.