Abstract: To protect the pump of a whirlpool bath against running dry and against blockage at the inlet, a pressure (or flow) sensor 14 senses pump pressure and generates a signal to keep a switch S2 in the pump motor electrical supply circuit closed. If the pressure signal ceases owing to blockage or running dry, the switch S2 opens. A manual override button 15 is held ON to close switches S1a and S1b in the power circuit for start-up. The sensor 14 and manual button 15 are preferably air pressure devices. Switch S1a is preferably an air-signal-operated latching switch whereby with the pump operating, the button 15 can be operated to switch the pump off. Relays RLA 1 and 2 may be used in conjunction with the electrical switches. A bleed hole may be provided between the button 15 and switch S1b to limit the period of time for which the motor could be run, with the bath empty, by prolonged inadvertent actuation of the button 15.

Abstract: Thin, flexible sheets of water-impervious plastic material have their margins heat-sealed together and enclose a layer of insulating material of a size sufficient to cover the internal area of a tub. An internal bladder is of a size sufficient to cover at least the major portion of the water surface area of the tub, is supported on the intermediate sheet and itself is covered by a thicker, weather-resistant top sheet. The margins of all of the sheets are secured together and adapted to be secured to the curb or deck of the tub.

Abstract: A dynamically balanced suction relief is provided for a hydrotherapy tub or spa in which a controlled amount of water under pressure is supplied from the water pump to an air inlet duct to maintain a column of water in the air duct under normal conditions.

Abstract: A support structure for a hydrotherapy hoist or pool lift comprises a U-shaped upper portion which extends over the decking at a side edge of the pool, and a lower portion welded to the intermediate limb of the upper U and extending down into the pool. The upper portion engages an upper anchorage at each side limb of the U, and a reaction pad at the lower end of the lower portion bears against the side wall of the pool. The hoist has a vertical column from which a short cantilever lifting arm projects, a patient support seat being mounted on the arm. A lifting mechanism is operable to raise and lower the arm and seat. The hoist is detachably supported by means of pintle-type bearings mounted, respectively, adjacent the upper and lower ends of the lower support portion with offset bearing pins on the column engaging in bearing blocks welded to the support. The bearings allow the hoist to be swung through 180.degree.

Abstract: A laminated ice suppression mat which prevents ice from forming adjacent to objects partially submerged in a body of water subject to natural icing conditions has a laminate of buoyant, thermal insulating material intimately joined to a larger laminate of a reinforcing material. A fringe of reinforcing material may become embedded in an ice sheet which forms around the mat and causes the mat to move upward and downward about the object as the ice sheet rises and falls with the changes in water level.

Abstract: The present invention is directed to a novel pulley assembly used in connection with conventional swimming pool cover systems of the type utilizing draw cords carried by a dual-channel track. The pulley assembly is comprised of a pulley housing and a pulley such that the pulley housing is adapted for securement at the end of a section of track. In a preferred embodiment, the housing is provided with a tang-like projection adapted to be received in a slot in the track between the two channels so as to maintain the pulley system in proper alignment with respect to the track and the pulley is rotatably secured within a cylindrical cavity having sufficient clearance to permit free rotation of the pulley, but the clearance being less than the diameter of the draw cord so that the draw cord will remain engaged with the pulley.

Abstract: A wheel assembly for use with extendible and retractable swimming pool covers having a raised leading edge. The apparatus of the present invention preferably comprises two rigid arms which each have a wheel attached to one end thereof. The other end of the arms are rotatably connected to an expandable plug which is adapted to fit into one end of the horizontal leading edge carrier member of the pool cover. A bolt passes through a washer, through an axial bore in the expandable plug, and through holes in the ends of both arms so as to connect all of the component parts together. A wing nut is then tightened onto the end of the bolt, thereby causing the expandable plug to expand within the leading edge carrier member. The wheel assembly is thus secured to the end of the carrier member, with the arms being prevented from further rotation after installation.

Abstract: A control system for selectively turning on and off various electrical devices used in the operation of a spa is disclosed. The control system includes a power supply for generating a 5 volt DC voltage from a 120 volt AC external power source, a timing circuit, a clearing circuit and a plurality of control circuits, one for each device to be controlled. Each control circuit, which is driven by the 5 volt DC voltage, includes a relay which is adapted to be coupled to the electrical device to be controlled, a momentary manually operated switch, a pair of flip-flops, a gate, a transistor, and an incadescent light bulb. In the operation of the circuit the transistor is turned on and off by the flip-flops and the output of the transistor is used to energize or deenergize the relay. Because the circuits operate at low DC voltage, the switches through which these voltages are transmitted can be located at or near the spa without causing potential safety problems.

Abstract: A liquid circulation system having a tank or tub of liquid and an external recirculation pump with one or more suction ports in the tank, and a submerged return port from the pump, having each suction port adjacent to, and preferably annular to, a return port. The entrapment of large objects in the suction port or ports is prevented by close proximity between the suction and return ports, particularly when the return flow constitutes a high-velocity jet as in hot tubs or spas.

Abstract: A swimming pool lift installation for the handicapped employs a platform for carrying a wheelchair that is lowered and elevated with the platform so that a handicapped person can sit on his chair and be lowered into the pool for swimming away from the chair and can leave the pool by swimming back into the wheelchair. The chair is releasably secured to the platform so that there is no danger of it being rendered unstable by its buoyancy in the water and so that it can be wheeled on and off the platform. A water hydraulic system operates the lift to avoid contamination of the pool.