A theftproof tag which is effective regardless of the material of the article to which it is attached. There is neither a change in resonance of a resonance circuit nor a decrease in the Q value due to the material of the surface of a theft monitored article, thereby decreasing errors in the operation of a theft monitor. The theftproof tag has a resonance circuit resonating to an electric wave at a specified frequency transmitted from a transmitting antenna, and having a coil unit and a capacito...

A theftproof device comprising a flexible tying member, an optical fiber extending through the flexible tying member, a light emission element arranged opposite an end of the optical fiber, a light receiving element arranged opposite the other end of the optical fiber, a fixture fixed to an object to be protected from theft, an electrical circuit arranged within the fixture, mechanical connector means for mechanically connecting the flexible tying member to the fixture, and electrical connector ...

A theftproof lock structure includes a number lock body, an alarm, an elastic plate, and a rotary wheel set including a plurality of number wheels and follower wheels. One of the follower wheels includes a boss, and the elastic plate includes a tilt abutting piece detachably abutting the boss. When the number wheels are rotated to a correct position, the alarm is closed. When the number wheels are rotated to deviate from the correct position, the follower wheels are rotated with the number wheel...

A theftproof device for a computer according to the present invention is provided. The theftproof device includes a PCB installed in a predetermined portion of the inside of a computer, an external connector portion provided on one side of the PCB for connecting to external cables, a vibration sensor installed on the PCB for sensing vibrations of the main frame of the computer, an alarm installed on the PCB for sounding an alarm when the main frame of the computer vibrates, a circuit provided on...

A street identification sign and supporting post assembly designed to be essentially theftproof and vandalproof. The sign boards are preferably made of cast aluminum and contain an integrally cast elongated rod that is also cast into the open top of the supporting post. The various components of the assembly are all integrally joined together with cast metal into a unitary street sign structure or assembly. Also disclosed is a method for producing the unitary structure or assembly using aluminum...

Systems and methods which provide a cover having a retaining piping disposed along an edge thereof to tether the cover to a vehicle or other object. Retaining piping is preferably disposed. such that a portion of the cover passes through an opening in the vehicle and the retaining piping cannot pass through the opening, thereby preventing the removal of the cover from the vehicle.

A theftproof automobile steering wheel lock comprising a rigid bar adapted to be attached diametrically to the steering wheel with one end at least extending beyond the rim of the wheel a sufficient distance so that rotation of the wheel in either direction is limited by engagement of the protruding end with an interior direction of the vehicle or operator.

A readily installed and removable coaxial cable connector assembly which is rendered theftproof by the provision of an end cap which may be manually thrust into an open end of a housing surrounding a coaxial cable connector coupling to close the open end of the housing and simultaneously render the coupling inaccessible. The end cap is releasably locked by a plurality of spring fingers formed on a leading end of the cap and movable with a snap action into an internal groove in the housing.

A theftproof lock device for a suitcase includes a housing, and a closure plate mounted on an opened side of the housing, and further includes multiple number wheel sets, two opposite press members, a drive plate, a slide, and a circuit board each mounted between the housing and the closure plate. Thus, the number wheel of the number wheel set for controlling the alarm may be rotated to an erroneous position, so as to start the alarm easily, thereby providing a theftproof effect. In addition, th...

A lockable coupling device for a truck trailer has a pin which can be moved axially out of baseplate for engagement with a coupling plate of a tractor. A shaft is operatively arranged to advance and retract the pin. The shaft is joined to a barrel rotatable by a crank. The barrel can be locked against rotation by a lock in the barrel. The crank carries a key for locking and unlocking the barrel. A motor may be provided to drive the shaft for extending the pin. The pin may be arranged to obstruct...