Abstract: A tamper resistant device designed to be fitted into the blind hole of a standard VHS videocassette tape in such a manner as to prevent use/loading of the cassette. The device consists of a cylindrical body, pawl, cross pin, spring and a key for removal of the device. This device provides much more security than the current state of the art. Contents of the videocassette can neither be damaged by recording over existing program(s) nor can they be viewed, as insertion of the cassette into a player/recorder is prevented by the device. Furthermore, the device is designed to be compatible with all existing sleeves or covers used for storage. The device can be easily engaged without use of the key. Also, the device cannot be removed until the pawl neutral position is maintained while the device is being removed. Both the pawl and key hole design serve as tamper resistant components. Until the pawl's neutral postion is achieved, either of two locking surfaces engage an under cut built into the videocassette.

Abstract: Quality control attachment adapted to be fitted onto a threaded depth control bar of a drill press machine includes a sleeve having an axial opening for fitting onto the control bar and being longitudinally movable relative to the bar. The sleeve carries a pawl and an elastic O-ring which urges an edge portion of the pawl into engagement with the threads of the control bar for enabling one-way movement of the control bar downwardly through the sleeve. An actuator pin is slidably disposed in a bore which extends through the sleeve and is movable downwardly in response to contact with a stop-nut disposed on the bar when the drill press has advanced to a preset depth represented by the position of the stop-nut.