Abstract: A shock and water resistant wireless pager enclosure, and a tamper-proof lockable enclosure system. The enclosure comprises a bottom container, which supports a transparent film, secured by a cover hinged to the bottom container. The enclosure system comprises an enclosure cover provided with securing members which lockingly engage the bottom container. A lock release tool comprises latching means for engagement with the securing members, and a cam and cam followers which operate on the latching means to pull the securing members outwards to release the locked engagement.

Abstract: A simple and effective apparatus and method is disclosed for identifying the presence of an emergency vehicle in the immediate vicinity of a motor vehicle. This apparatus may be readily mounted and will not produce false alarms. The apparatus comprises: a transmitting unit, positioned within the emergency vehicle and having an activation circuit that turns on a digital identification data encoder that modulates an R.F. transmitter producing a digital data stream which is connected to a broadcast antenna; and, a receiving unit, carried by a motor vehicle so that it may be warned if the emergency vehicle is in its immediate vicinity having and having a R.F. receiver that demodulates a received digital data stream and then activates an alert pulse generator which is connected to an alarm means if the digital identification code matches the digital identification encoded in the transmitting unit. In a preferred aspect of this invention the digital identification data encoder modulates the R.F.

Abstract: Apparatus for detection leakage of hydrocarbon-containing liquid, such as gasoline, from a generally cylindrical tank. The apparatus includes an elongate displacer having a vertical axis and extending substantially the full height of the liquid in the tank. The displacer has an upper end and a lower end with the displacer lower end terminating closely adjacent but spaced from the bottom of the tank. The displacer is made of a material having a coefficient of linear expansion of less than 20.times.10.sup.-6 inches per inch per degree centigrade. Furthermore, the displacer is substantially symmetrical about about any plane through its vertical axis and it has an outer surface which is a surface of revolution. The displacer has a varying diameter along its length corresponding to the horizontal surface area of the tank at the same height inside of the tank. The apparatus further includes a sensor for providing an indication of the weight of the displacer disposed in the liquid.