Security alarm switch

A magnetic switch assembly for detecting relative movement between first and second adjacent members, and for defeating attempted magnetic manipulation of the switch assembly so as to permit said relative movement without detection thereof, said switch assembly comprising:

• a pair of adjacent, superposed, upper and lower switch elements for mounting on said first member, said lower switch element presenting a sloped surface;
• a shiftable, ferromagnetic body disposed between said elements and movable along said sloped surface between spaced upper and lower switch operating positions;
• and
• a magnet for mounting on said second member and oriented for retaining said body in said upper switch operating position when said members are in one relative position, and, upon movement of the members to a second relative position, for permitting shifting of said body along said sloped surface to said lower switch operating position for retention thereat under the influence of gravity,
• said switch elements being located for movement of said body from said upper to said lower switch operating position, when said members are in said one relative position and an external magnet is applied to said first member in an attempt to magnetically manipulate the switch assembly.