Abstract: A captive fastener including a bushing having a body portion and an internal bore extending through the body portion A snap ring is mounted within the internal bore. A fastener having an elongated shaft is mounted within the bore and is adapted to reciprocate within the bore between retracted and extended positions. The elongated shaft has a shank diameter and threads formed on one end of the fastener. The snap ring engages the bolt when the shaft is extended and retracted. The fastener has a shank diameter which is 0.020 inches to 0.060 inches shorter than the bore diameter so that the fastener can be moved laterally within the bore.

Abstract: A test apparatus is disclosed that has a housing containing a location at which a sample tray containing a plurality of sample wells can be located, a light box positioned to permit irradiation of the sample tray, and an imaging arrangement to permit imaging of the sample tray. The light box has a light source including a light guide in the form of a plate of a transparent material and a plurality of light emitting devices provided adjacent at least one edge of the plate where a surface of the plate is provided with a plurality of transmitting regions and light is transmitted from the plate.

Abstract: A captive fastener including a bushing having a body portion and an internal bore extending through the body portion A snap ring is mounted within the internal bore. A fastener having an elongated shaft is mounted within the bore and is adapted to reciprocate within the bore between retracted and extended positions. The elongated shaft has a shank diameter and threads formed on one end of the fastener. The snap ring engages the bolt when the shaft is extended and retracted. The fastener has a shank diameter which is 0.020 inches to 0.060 inches shorter than the bore diameter so that the fastener can be moved laterally within the bore.