Abstract: A water-impermeable membrane assembly for sealing a surface of a substrate comprises a waterproofing sheet and a plurality of conduits having openings in at least a first major surface, and a leak-alarm circuit disposed at least partly within said equipment space, the leak alarm circuit having a leak-alarm target operative to trigger activation of the leak-alarm circuit when in contact with a water-containing liquid. The leak-alarm circuit comprises an electronic circuit comprising a transmitter and a battery for transmission of a signal. The assembly also includes a capillary pathway disposed within at least a portion of the conduits, including at least one conduit in fluid communication with the equipment space and with respective openings disposed in at least said first surface, so as to provide a pathway for transport of a water-containing liquid by capillary action from said openings to said leak-alarm target.

Abstract: A water-impermeable membrane assembly, having leak alarm capabilities and useful for sealing a roof surface, comprises upper and lower water-impermeable membranes sealed to each other at respective perimeters to form a plenum enclosed from above and below with area defined by the perimeter sealing, a leak-alarm circuit within the plenum, activatable by the presence of water, a leak-alarm target in the circuit being operative to trigger activation of the leak-alarm circuit when in contact with water, and a capillary pathway disposed within the plenum in contact with the leak-alarm target, to provide a pathway for transport of water by capillary action to the leak-alarm target. The leak-alarm circuit comprises a transmitter for transmitting a signal when activated, and a battery for powering the transmission of the signal. A ratio of leak-alarm target footprint to plenum area is less than 0.05.

Abstract: A spyhole viewer for a door or wall, includes an objective system for producing a real, inverted image. The objective system is mounted in a tubular member fixedly installable in the door or wall. An erector is provided for inverting the inverted image of the objective system and is located behind at least one of the elements of the objective system. At least one reflector is provided for angularly deflecting the light beams from the objective system, and a housing is fixedly attachable to the tubular member for accommodating at least the erector and the reflector. A viewing lens is provided for magnifying the real image as inverted by the erector means. The viewing lens is adapted to swivel in a substantially vertical plane about an imaginary horizontal axis at a radius of swivel at least approximately equal to the length of the light path from the image-side focal plane of the objective system to the first principal plane of the viewing lens.

Abstract: A binocular mountable on a headgear, includes two optical systems, one for each eye of the user. Each system includes at least an objective lens and an eyelens. The binocular is pivotably attached to the headgear. When the headgear is in position on the user's head, the objective lenses and the eye lenses can be quickly swiveled out of the way to facilitate free and unaided vision, and returned to the position of binocular-aided vision. The binocular optical systems can be configured to provide either telescopic or microscopic effects. Moreover, the mounts of the lenses are transparent and integrally formed with the respective lenses. Thus, a continuity of visual field without "tunnel" vision is achieved. Hook and loop type fasteners can be used to attach the optical systems to the headgear, which can be either a cap or a visor. Additionally, a laser light/sun light shield can be provided. The optical systems can define bifocal optical systems. A single optical system (i.e.

Abstract: A spyhole viewer, mountable in a wall surface is disclosed and provides a wide angle view, while requiring a small diameter mounting hole. An objective lens system produces a real inverted image, a reflector angularly deflects light from the objective lens system, and an erector, located behind an element of objective lens system, erect the image. Further, a image surface upon which the image will appear, and a projection viewing lens are provided. The image optical axis is angularly deflected at least once between the objective and viewing lens systems.

Abstract: A binocular telescope mountable on a headgear, which comprises two optical systems, one for each of the user, each system constituting at least an objective lens and an eyelens. The telescope is pivotably attached to the headgear. When the headgear is in position on the user's head, the objective lenses and the eyelenses can be swiveled out of the way to facilitate free and unaided vision, and returned to the position of telescope-aided vision.

Abstract: A sighting device for day and night use having a beam-splitting means mounted in the line of sight between a target and the user's eye, a first source of light, being a self-energized source of artificial light, a second source of light, being an ambient-light admitting element, at least one aiming mark illuminatable by at least one of the sources of light, and at least one light-directing means adapted to project the aiming mark onto the beam-splitting means.

Abstract: Line of sight optical communications apparatus comprising a plurality of optical beam reflectors arranged in a protected region for optical communication therebetween, at least one of the reflectors being arranged to reflect a signal received at the reflectors to a base location remote from the protected region. Stabilized reflector apparatus which is insensitive to rotation about axes lying in a given plane and which is particularly useful in the line of sight optical apparatus is also described.