Abstract: The locking device for an electrical plug comprises essentially a housing containing a lock mechanism, wherein the lock mechanism is a subassembly insertable into the housing. The lock mechanism comprises a lock body having a pair of spaced walls extending from a face wall which is provided with a centrally located aperture adapted to receive a manually operable key. The spaced walls provide a camming bed for rotatably supporting a cam member provided with an elongated cam slot. A pair of lock plates are provided with prong locking projections which are adapted to engage the openings in the prongs of the electrical plug, said locking projections also supporting said lock plates in opposed slots in the spaced walls. The opposite side of the cam member is provided with a key-engageable means which extends into an enlarged chamber between the spaced walls. The lock plates are also provided with transversely extending cam fingers which engage the cam slot.

Abstract: A checking device for checking the operativeness of smoke alarms and for resetting the smoke alarms once they have been triggered comprises an elongated member in the form of a rod having one end provided with means which are adapted to engage test buttons on the smoke alarms and on the other end thereof, a smoke wafting means in the form of a fan for removing or dissipating accumulated smoke on the interior of the smoke alarms. During a test procedure, the checking device is positioned against the smoke alarm so that the testing means engages a test button to thereby cause the smoke alarm to give off an audible alarm signal. Failure of the smoke alarm to respond during the testing procedure indicates the failure of an internal electrical source. The checking device is utilized for resetting the smoke alarm after it has been triggered by a spurious source of smoke or by-products of combustion, such as smoke arising out of cooking or smoking tobacco in confined quarters.

Abstract: A line indicating apparatus for visually monitoring changes of physical constants or functions occurring in a dynamic process. The apparatus has a plurality of units or modules which are associated with the monitoring of a corresponding plurality of variables. Each module has at least two indicating sections, each of which is provided with at least two indicating members. An electric circuit is provided for sensing the condition and changes in each monitored variable and providing various outputs to energize one or more indicating members to give a visual indication of the condition of the monitored variable. The modules are aligned with each other in a straight line so that during normal or mode "A" operation of all the variables, particular indicating sections in all of the modules will present a highly visible indicating line or band.

Abstract: A control system for regulating the flow of water to the condenser to maintain most effective loading of the compressor in a water-to-air heat pump arrangement. The system incorporates a temperature sensitive valve which has a thermal transfer contact with the refrigerant flowing through the heat pump compressor which upon sensing the heat in the refrigerant rising or falling correspondingly variably opens and closes the water line to the heat exchanger so as to maintain the temperature at the compressor within a predetermined range, and maintain proper loading on the compressor during heating and cooling cycles of the heat pump.