Product monitoring device

A releasable locking device adapted to be secured to a product, comprising:

• a pair of relatively movable members;
• a locking element comprising bimetallic means having different configurations at different temperatures movable between a locking position in which said members are locked together and a release position in which said members are unlocked from each other to permit relative motion thereof;
• for controlling movement of said locking element from one of said positions to the other thereof;
• means for controlledly applying an electrical current to said bimetallic means to change its temperature and thereby control the locking and unlocking of said members;
• said movable members having ends thereon adapted for movement to mating positions as said members are moved to the locked position thereof;
• one of said ends having a groove therein;
• the other of said ends having a projection thereon;
• and
• said projection being operatively engaged within said groove as said members are moved to the said locked position thereof, and when so engaged constituting means opposing a relative twisting of one said movable member with respect to the other and thereby deterring disengagement of said ends by a relative twisting movement therebetween.

A releasable locking device adapted to be secured to a product, comprising:

• a pair of relatively movable members;
• a locking element comprising bimetallic means having different configurations at different temperatures movable between a locking position in which said members are locked together and a release position in which said members are unlocked from each other to permit relative motion thereof;
• means for controlledly applying an electrical current to said bimetallic means to change its temperature and thereby control the locking and unlocking of said members;
• said members including a pair of arms, one of said arms mounting at its terminal end at least one pin member engageable in at least one socket in the terminal end of the other arm;
• said terminal ends being adapted for movement to mating contacted positions as said members are moved to the locked position thereof;
• one of said ends having a groove therein;
• the other of said ends having a projection thereon;
• said projection being operatively engaged within said groove as said members are moved to the said locked position thereof, and when so engaged constituting means opposing relative twisting of one movable member with respect to the other and thereby deterring disengagement of said ends by a relative twisting movement therebetween.

In a product monitoring system comprising an electrically releasable locking device adapted to be locked to a product, said locking device being detectable upon unauthorized removal past a predetermined checkpoint, and an electrically powered key operative to release said locking device when applied thereto to permit removal of said device from said product for subsequent authorized removal of said product, wherein;

• said electrically releasable locking device includes a pair of relatively movable members;
• a locking element comprising bimetallic means having different configurations at different temperatures movable between a locking position in which said members are locked together and a release position in which said members are unlocked from each other to permit relative motion thereof;
• means for controlledly applying an electrical current to said bimetallic means to change its temperature and thereby control the locking and unlocking of said members;
• said movable members having ends thereon adapted for movement to mating positions as said members are moved to the locked position thereof;
• one of said ends having a groove therein;
• the other of said ends having a projection thereon;
• and said projection being operatively engaged within said groove as said members are moved to the said locked position thereof, and when so engaged constituting means opposing a relative twisting of one said movable member with respect to the other, and thereby deterring disengagement of said ends by a relative twisting movement therebetween.