Abstract: A modular bonded perimeter skimming gutter retaining wall for swimming pools is provided for construction by simple bonding together of a plurality of modular units on-site, disposed about the perimeter of a swimming pool as the retaining wall of the swimming pool, defining a pool-side wall of an open gutter conduit adapted to carry water at a level below a predetermined level of water in the swimming pool, over the top of which wall water may flow from the pool into the gutter, the retaining wall comprising two generally U-shaped channels open along one side and having open interiors defined by side walls extending from a common base, the channels being arranged with the open sides facing one another and bonded together along the end faces of the side walls to a common divider plate closing off each channel and the interior spaces thereof, thereby forming separated conduits of each channel, one of said conduits being adapted to carry clean water feed to the pool and the other of said conduits being adapted t

Abstract: A step ladder is shown, having a rigidified step section, a strengthened upper platform, two independently articulated angled rear legs, supported by a pair of rigid, pivoting supports. The angle of extension of the rear legs creates, in conjunction with the front step section of the step ladder, an essentially equilateral, triangular footprint of increased stability. The individual legs, in cooperation with a strengthened, rigid top plate structure, and the single member rigid support strut produces a decreased likelihood that the ladder will "walk" or move under the shifting weight of a user. The triangular footprint creates increased static stability, and also reduces the likelihood of toppling as a result of movement of a person standing on or near the upper step. The support leg actuation linkage is vertically fixed along a linkage support shaft. By fixing the linkage in three dimensions, torsional rigidity is maintained between the independent legs and walking motion is eliminated.

Abstract: A vacuum filter is provided for vacuum flow filtration through a filter bed of water from a swimming pool including flow from the pool and from the gutter of the swimming pool, and controlling water recirculation capacity to accommodate varying gutter flow, comprising a tank; a filter bed of particulate material in the tank; a first inlet line communicating the swimming pool with the tank for gravity flow into the tank and maintaining a predetermined level of water in the tank in relation to a level of water in the swimming pool, thereby providing a head of water for gravity backwash flow through the filter bed; a second inlet line communicating the tank with the perimeter gutter for the swimming pool for gravity flow into the tank; a third inlet line communicating the tank with the perimeter gutter for the swimming pool for suction flow into the tank; an outlet line communicating the tank with the water recirculation system; a pump drawing a vacuum downstream of the filter bed and recirculating filtered wate

Abstract: A modular bonded perimeter skimming gutter retaining wall for swimming pools is provided for construction by simple bonding together of a plurality of modular units on-site, disposed about the perimeter of a swimming pool as the retaining wall of the swimming pool, defining a pool-side wall of an open gutter conduit adapted to carry water at a level below a predetermined level of water in the swimming pool, over the top of which wall water may flow from the pool into the gutter, the retaining wall comprising two generally U-shaped channels open along one side and having open interiors defined by side walls extending from a common base, the channels being arranged with the open sides facing one another and bonded together along the end faces of the side walls to a common divider plate closing off each channel and the interior spaces thereof, thereby forming separated conduits of each channel, one of said conduits being adapted to carry clean water feed to the pool and the other of said conduits being adapted t

Abstract: An automated skimming flow perimeter gutter control system for swimming pools is provided having a water cleaning and recirculation system receiving water from the pool, cleaning it, and returning it to the pool; a gutter conduit for disposition about the perimeter of a swimming pool, receiving overflow across a top edge thereof and adapted to carry water at a level below a predetermined level in the swimming pool; a drain line connecting the gutter conduit with the water recirculation system; suction means in series flow connection with the gutter conduit and drain line for positive withdrawal under suction of water from the gutter conduit and feed of such water to the water recirculation system for return to the pool; at least one of (a) means for controlling water recirculation capacity to accommodate any selected flow of water from the gutter to the water recirculation system; and (b) means for controlling suction flow from the gutter to the water recirculation system; and at least one water level-respons

Abstract: An apparatus is provided for making waves in bodies of water used for swimming, having a plurality of hollow open-bottom pistons mounted for reciprocation in alternating power and suction strokes in which the movement of each piston engaged in a power stroke is opposed to the movement of an adjacent piston engaged in a suction stroke; each piston confining a gas cushion between the top and any water within the lower portion of the piston that is under a superatmospheric pressure during a power stroke of the piston, and under a subatmospheric pressure during a suction stroke of the piston; whereby on the suction stroke each piston draws water into its interior via its passage and port from the body of water, and on the power stroke each piston pushes water from its interior via its passage and port back into the body of water, the resulting alternating pulses of water flow generating waves in the body of water.

Abstract: An apparatus is provided for making waves in bodies of water used for swimming having a multicompartmented chamber with at least one set of separate paired compartments open in a nonintercommunicating lower portion for separate reception of water therewithin from a body of water, and closed in an intercommunicating upper portion in a manner to provide a fluid-tight upper portion confining therewithin a volume of fluid that is common to each pair of compartments; and at least one pair of pistons, each disposed in separate paired compartments in the chamber, each piston being mounted across its compartment for reciprocation in alternating power and suction strokes and arranged for fluid-pressure-induced interreaction with the other piston in balanced strokes; each piston having an upper face with a pressure-receiving surface responding to fluid pressure in the upper portion of its compartment, and a lower face with a pressure-receiving surface responding to water pressure in the lower portion of its compartment

Abstract: An automated skimming flow perimeter gutter control system for swimming pools is provided having a water cleaning and recirculation system receiving water from the pool, cleaning it, and returning it to the pool; a first drain line connecting the pool to the water recirculation system for water feed from the pool for cleaning; a gutter conduit for disposition about the perimeter of a swimming pool, receiving overflow across a top edge thereof and adapted to carry water at a level below a predetermined level in the swimming pool; a second drain line connecting the gutter conduit with the water recirculation system for water feed from the gutter for cleaning; skimming means receiving skimming flow across a top edge thereof at the perimeter of the swimming pool; a first drain valve in the first drain line which when open allows water from the pool to flow to the water recirculation system, and when closed stops such flow; a balance means in flow connection with the first and second drain lines and the water reci

Abstract: A perimeter skimming gutter for swimming pools is provided including a gutter conduit for disposition about the perimeter of a swimming pool and adapted to carry water at a level below a predetermined level of water in the swimming pool; a retaining wall on the pool side of the conduit over the top of which wall water may flow from the pool into the gutter conduit; a weir flow passage providing a fluid flow connection between the pool and at least one gutter conduit, entering the pool through the retaining wall at a level below the top thereof; and a fluid level responsive buoyant weir closure in the weir flow passage; a flow restriction in the weir flow passage confining normal weir flow through the weir flow passage to the gutter conduit to a predetermined maximum, the flow restriction blocking flow in excess of the predetermined maximum and thereby increasing fluid level in the weir flow passage between the weir closure and the pool; the weir closure responding to increasing weir flow passage fluid level t

Abstract: A fully automated pool level and skimming gutter flow control system is provided, automatically establishing and controlling pool level and skimming gutter flow under both normal and extraordinary pool use conditions, sensing changes in water level and water activity, and actuating appropriate response mechanisms controlling water feed and skimming gutter drain flow, as well as make-up water and rate of recirculation of the water between the pool and the filtration system.

Abstract: A fully automated surge weir and rim skimming gutter flow control system is provided, automatically establishing and controlling surge weir and rim skimming gutter flow under both normal and extraordinary pool use conditions, sensing changes in water level and water activity, and actuating appropriate response mechanisms controlling surge weir and rim skimming gutter flow and/or rate of recirculation of the water between the pool and the filtration system with switches to convert the gutter from weir skimming and back.

Abstract: A vacuum filter for vacuum flow filtration through a filter bed of water from a swimming pool is provided, comprising an open-top tank; a filter bed of particulate material in the tank; fluid flow connections communicating the tank with a water recirculation system for the swimming pool, one adjacent an upper portion and one adjacent a lower portion of the filter bed; an inlet line communicating the swimming pool with the tank and maintaining the level of water in the tank at a level corresponding to a level of water in the swimming pool, thereby providing a head of water for gravity backwash flow through the filter bed, and valves controlling flow into the tank via the fluid flow connections between the tank and the inlet line, and between the tank and the water recirculation system; and a direct fluid flow connection communicating a gutter drain of the swimming pool with the tank; a vacuum is drawn downstream of the filter bed by a pump recirculating filtered water to the swimming pool.

Abstract: A quickly tensioned divider line for swimming pools is provided, comprising, in combination, a first divider line adapted for attachment to a first fixed location in a swimming pool; and a tensioning toggle attached to the line, and adapted for attachment to a second fixed location in a swimming pool, optionally, via a second divider line, the first and any second line thereby being located with the toggle in a divider line position in the pool; the toggle having first and second toggle arms, the first toggle arm being pivotably mounted on the second toggle arm, and movable between retracted and extended positions, in the retracted position being axially coextensive over at least a part of its length with respect to the second arm, and in the second position being axially extended over at least a part of its length with respect to the second arm; attaching means pivotably mounted on the first toggle arm, for movement therewith between its retracted and extended positions; and attaching means on the second tog

Abstract: The invention is a special, low-friction, compliant bearing seal for use between the stationary and movable members of a thrust-vectoring, rocket nozzle. The movable member of such nozzles typically contains the throat and expansion cone for acceleration of the propulsive gases. It is attached to the back end of the rocket by the stationary member. A torsion ring, seated in an annular groove in the stationary member of the nozzle holds an annular, lubricous pad against a spherical surface of the movable member. An elastomeric pad bonded between the adjacent surfaces of the torsion ring and the groove, both of which are arcuate in cross section, permits twisting motion of the torsion ring; so that the lubricous pad maintains its seal and bearing function relative to the movable member, despite temporary deformations of the nozzle members during operation of the rocket.

Abstract: A roofing system is provided for large-area wide-span building structures such as natatoria, comprising an interlocking gridwork of purlins supported on beams. A portion of the structure can be provided with a track, and another portion of the structure mounted on wheels movable along the track, so that one portion of the roof may be slid open or closed by movement along the track, so as to open the interior of the building structure to the atmosphere.

Abstract: A wave-quelling float for marking lines extending across the surface of a body of water is provided, comprising a supporting body of lightweight plastic material; a hub in the body with a central passage therethrough for reception of a float-tethering marking line; a plurality of buoyant members arranged radially about the hub, and preferably disposed at regular intervals about the hub to float the body in a manner such that at least one-half the body is above the water with the float balanced for free rotation in the water about a float-tethering line; the body having a web portion extending radially from the hub, and a plurality of wave-quelling vanes extending laterally from the web on at least one side thereof; the vanes being spaced and shaped to receive surface surges and waves on the body of water, absorb the impact thereof as rotation of the float, and thereby quell them.

Abstract: A perimeter gutter for swimming pools is provided comprising, in combination, first and second gutter conduits for disposition about the perimeter of a swimming pool, of which conduits at least one is adapted to carry water at a level below a predetermined level of water in the swimming pool; a retaining wall on the pool-side of the gutter conduits, over the top of which wall water may flow from the pool into one of the gutter conduits; the first and second gutter conduits having at least one common wall therebetween, separating interior space of the second gutter conduit from interior space of the first gutter conduit, of which common wall at least a portion is removable, so that upon removal of the wall, said interior spaces are combined and form a gutter whose interior space is greater than the interior space of either gutter conduit.The second gutter conduit can be in fluid flow communication either with the swimming pool or with the first gutter conduit, or with both.

Abstract: An extendible nozzle for a rocket motor or the like which nozzle is positioned in the aft end of the motor is disclosed having a main nozzle portion with an exit and entrance thereto and a plurality of elongated petals representing longitudinal sections or strips of a conically shaped structure hingedly connected by means of hinges at their forward ends to the exit portion of the main nozzle portion. The petals are selectively movable from a first or stowed position where the petals are all radially outward and slightly forward of the hinge locations to a second or deployed position where the petals form a smooth conical extension of the exit portion of the main nozzle portion. The petals are positioned to be in as close proximity to the aft motor dome of the rocket motor as possible while still allowing the required envelope or spacing for rocket dome-mounted components which are necessary to accomplish other motor/nozzle functions.