Abstract: A rotatable nozzle assembly (13) having a nonaligned fluid (water) supply (7-2) disposed in such a way that the water supply (7) is perpendicular to the rotating axis of the nozzle (13) and arranged such that water supplied perpendicular to the rotating axis of the nozzle will be bent to be in alignment with and next to the axis of the nozzle to produce a concise small nozzle assembly that is adaptable to stripping coatings on internal surfaces of tubes or the like.

Abstract: A lift mechanism (15) for the cover (13) of a portable spa or hot tub (11) comprising a pair of compressible struts (21) and upper and lower hinge mechanisms (24 and 23) is disclosed. The preferred lower hinge mechanism (23) includes a torque tube (25) rotatably mounted through bushings (31) housed in plates (27). The plates (27) are located at a pair of adjacent lower corners of the spa or hot tub (11) and held down by the weight of the spa or hot tub (11). The struts (21) are attached to the ends of the torque tube (25). The other ends of the struts are attached to opposite sides of the spa cover by the upper hinge mechanisms (24), which preferably include brackets (33) that are fixed to the cover and pivot nuts (71) that rotatably attach the brackets (33) to the struts (21). When the cover is in its closed position, the struts (21) incline upwardly toward the center of the spa or hot tub (11). When the cover (13) is in its open position, the struts (21) lie substantially vertical.

Abstract: The invention is especially suitable for profile measurements on non-specular surfaces. The surface of interest is intersected by projected interference fringes generated by two intersecting coherent light beams. The intersected fringes are imaged at a photo-electric detector having a sensitive cross-sectional area relative to the fringe pitch, suitably half a fringe pitch, such as to produce an output variation if the fringes move relative to the detector. The phase of at least one of the beams is modulated to cause the fringes to shift laterally and cyclically across the surface, thereby causing the detector output to include a sinusoidal component whose phase depends on the distance to the imaged surface. The change in phase of this component, if and as the distance to the surface changes, is used to indicate the change in the distance.To measure distance changes greater than the depth of focus of the detector, it is aranged that, after such a change, the detector moves axially to a refocussed position.