Abstract: A flooding prevention device and a breakage prevention device for use with pressurized fluid systems are disclosed. The flooding prevention device includes a pipe with an interior passageway and a stopper located in the passageway, the stopper being adapted to seal the pipe whenever an accessory attached to the pipe is broken, thereby preventing fluid loss from the pressurized fluid system. The breakage prevention device includes a first pipe and a second pipe slidable within the first pipe, the sliding action accommodating pressure on or movement of components of the fluid system, thereby avoiding component breakage.

Abstract: A method and system for conducting multiple access simultaneous telephone communications in full duplex either over the power lines of a building or using RF transmission. It employs a combination of multiple access techniques selected from among the following: time division, code division, and frequency division. The following features result: a) security coding to prevent unauthorized access and eavesdropping, b) multiple simultaneous conversations through identical and closely coupled transmission media, c) non-interference to other communications systems and users, and d) processing gain for operating in noisy environments.

Abstract: A golf car towing hitch system for towing a three or four wheeled golf car behind a passenger vehicle or light truck with the rear two wheels of the golf car elevated off of the ground. A hoist mounted on a rotable mast for lifting the rear of the golf car is included. Receiver or bar hitches may be used.

Abstract: A yieldable confined core mine roof support including a container and a filler placed within the container. The container is yieldable and the filler is compressible. The combination of a filler within a container produces a mine roof support which is yieldable under a substantially axial load and which increases in load carrying ability as it yields, impeding any decrease in the distance between a mine roof and a mine floor, minimizing or preventing mine roof collapse and mine floor heave, buckling or punching.