Abstract: An ultrasonic transceiver device and remote output devices controlled by the transceiver for use by domestic pets. The transceiver utilizes a fixed interval edge detect modulation system to lock out stray environmental noise thereby, avoiding false triggering and greatly increasing the working range. Output devices include: a wireless pet containment system in which ultrasonic transmitters are mounted on a series of posts defining the perimeter of the containment area and a receiver device adapted to be worn by a domestic animal.

Abstract: A punching tool for piercing a hole through the substantially parallel, spaced apart plates of a data storage disk casing uses a die which supports one of the plates and an elongated punch which pierces through the plates in succession. The disk is placed on a tray on the punch's base, and a drive lever is pushed downward to drive the punch through the casing plates. The punch is guided so that it moves along its axis of elongation and has a cutting surface at its end with a point to begin the hole in each of the plates and a trailing edge spaced apart from the point which completes the hole. The distance between the point and the trailing edge is great enough to allow the point to begin a hole in a succeeding plate before the trailing edge completes the hole in the previous plate.

Abstract: An ultrasonic transceiver device and remote output devices controlled by the transceiver for use by domestic pets. The transceiver utilizes a fixed interval edge detect modulation system to lock out stray environmental noise thereby, avoiding false triggering and greatly increasing the working range. Output devices include: a wireless pet containment system in which ultrasonic transmitters are mounted on a series of posts defining the perimeter of the containment area and a receiver device adapted to be worn by a domestic animal.