Abstract: In accordance with the present invention a cast or machined housing contains a drive system for turning a rotating cutter. An external source of rotation is attached to the housing. This external source can be a commercially available tool, such as a Craftsman angle grinder, or any rotating source of power provided by electric, hydraulic, or pneumatic means.

Abstract: A device for safely lowering persons from upright structures such as buildings during an emergency at a safe, predetermined speed of no more than about four feet per second irrespective of the weight of the person being lowered. The device has a drum about which a cable is wound, a gear pump driven by the drum via a reduction gear train, and a hydraulic circuit which includes the gear pump and a flow control valve which maintains a constant hydraulic fluid flow through the circuit irrespective of the weight of the person being lowered and, therefore, also irrespective of the fluid pressure generated by the pump during operation. The hydraulic circuit is in fluid communication with a hydraulic fluid tank having an exterior surface dimensioned to cool the hydraulic fluid and prevent its temperature from rising by more than about 200.degree. F. above the ambient temperature during operation of the device.

Abstract: Apparatus for shaping the end portions of a reflective film to conform to a spherical shape comprising attaching the end portions of the film to flexible stretch blocks so the film wraps over a surface of the blocks which can be bent to arc positions matching the arc of curvature at the ends of the frame which carries the film in its final spherical configuration, and forcing the stretch blocks to flex about a neutral axis so the surface of the blocks which bend to match the arc of curvature at the ends of the frame move about fixed end points from a chord configuration to an arc configuration matching that of the ends of the frame thereby substantially uniformly stretching the film into its final spherical configuration.