Abstract: Apparatus for generating waves in a swimming pool comprises a reservoir, independent of and separate from the pool, the reservoir containing a volume of water to be supplied to one or more inlets communicating into the lower regions of the swimming pool, and one or more flow paths through which the water from the reservoir is fed to the or each inlet, the or each flow path including a flow control valve therein and a volume of air downstream of the associated control valve for entrainment with the water flowing to the swimming pool such that, on entry of the water into the swimming pool, a wave having a turbulent, air-containing wake is formed.

Abstract: In an excavating machine having a lower frame, an upper frame and means for rotatably supporting the upper frame on the lower frame, an assembly for improving the load conditions of the upper frame supporting structure comprising an annular seal mounted on one of the upper and lower frames and disposed in wiping, sealing engagement with the other of the upper and lower frames, forming a sealed chamber between the upper and lower frames, and air is supplied under pressure to the chamber to provide an upwardly directed force on the upper frame alleviating the load imposed on the upper frame supporting structure.