Abstract: A reflector for electromagnetic radiation with an easily replaceable reflective membrane that is especially useful in solar collectors. The reflector comprises an annular housing, an elastic reflective membrane, a ring supporting the membrane, an evacuation assembly for evacuating the housing and drawing the elastic membrane into the housing, and a fastening assembly which releasably snap-fits the ring and membrane assembly to the housing in a gas-tight manner.

Abstract: A curved reflector of electro-magnetic radiation formed of an elastic, imperforate reflective membrane utilizes a partial vacuum to provide the curvature to the membrane. The device for controlling the evacuation of the housing can be supported within the reflector housing in an adjustable manner to set the control device at a location corresponding to a predetermined deflection of the membrane below a reference plane, and thereby, to permit the focal length of the reflector to be varied. The control device can comprise a membrane contact surface surrounding an orifice which controls, with the interior surface of the membrane, fluid communication between the housing interior and the evacuation mechanism. Other control devices include an electrical limit switch, a light source and sensor, a capacitor or inductor sensing arrangement and a magnetic field sensing arrangement. The membrane can be releasably coupled to the housing via springs to facilitate replacement thereof.

Abstract: A space frame formed from a first set of beams and joints in a first plane and a second set of beams and joints in a second plane, the joints in the two planes being interconnected by diagonal tubular struts. Each strut has two shafts at opposite ends which are received, respectively, in apertures in a joint in the first plane and a joint in the second plane. Each shaft has a fastening member coupled thereto for maintaining the shaft in the aperture. Each shaft extends along the longitudinal axis of the associated tubular strut.

Abstract: A joint for connecting tubular beams comprising two caps receiving deformed end portions of the beams therebetween. Each cap has a tapering tubular portion in contact with the end portions, each end portion having first and second outwardly diverging opposed faces and third and fourth inwardly converging opposed faces. The outer perimeter of the end portion is greater than the perimeter of an opening defined on the top and bottom by the two caps and on the sides by adjacent beams, so each end portion is highly resistant to forces tending to pull it from between the caps and must be mechanically deformed before it will be pulled through the opening.

Abstract: A system for concentrating electro-magnetic radiation, such as solar radiation, by means of a plurality of reflectors mounted on a common frame and aimed at a radiation absorber that is rigidly coupled to the frame by an intermediate support. The combined frame, reflectors, absorber and intermediate support are coupled to a cantilever beam by means of a suspension assembly located between the absorber and the reflectors. This suspension is at the center of gravity of the combined frame, reflectors, absorber and intermediate support. The cantilever beam is coupled at one end to a main support and at the other to the suspension assembly. This suspension assembly allows the combined frame, reflectors, absorber and intermediate support to pivot relative to the beam about two perpendicular axes.

Abstract: A curved reflector of electro-magnetic radiation formed of an elastic, reflective membrane which utilizes a partial vacuum to provide the curvature to the membrane and an adjustable valve to vary such curvature, and therefore the focal length of the reflector. The valve comprises a central aperture in the membrane and a body adjustably mounted above the aperture with a flow restricting surface thereon which overlies the aperture.