Abstract: A drive circuit for operating a resonant motor includes a motor circuit, a feedback circuit, a control circuit, and a coil drive circuit. A feedback loop includes the motor circuit, the feedback circuit, and the control circuit. The feedback loop in conjunction with the coil drive circuit monitors, maintains, and adjusts the oscillatory motion of the resonant motor. The drive circuit is suitable for operating a resonant motor of an optical code reader.

Abstract: An optical scan module includes a scanner for scanning a scanning beam over a target plane at which indicia to be electro-optically read is located, and a pair of spaced-apart detectors for sensing light reflected from the indicia over respective fields of view. The detectors have optical axes intersecting each other, generate respective electrical signals indicative of the indicia, and are connected to a multiplexer for selectively acquiring one of the signals based on the direction of the scanning beam. The acquired signal is decoded by a decoder.

Abstract: An optical scan module having a base; a light source mounted on the base for emitting a light beam; a scanning assembly for receiving the light beam and for generating therefrom a scanning beam directed to an indicia to be read for reflection therefrom; first and second spaced apart detectors receiving the reflected light represented by the indicia, with each detector having a different field of view; and means for selectively acquiring the signal from either the first or the second detector and applying such signal to a decoder.

Abstract: A modular scaffolding assembly in which the platform may move up or down in a continuous motion. A platform carriage is engaged with a tower by spring loaded friction blocks and climbs or descends the tower along a pair of stepped racks. Platform modules may be removably connected to the platform carriage.

Abstract: Apparatus comprising a liquid flow path having two parallel connected sections, namely a first section adapted to provide turbulent flow and a second section adapted to provide laminar flow. Water flowing through the apparatus divides between the two sections in a ratio which is arranged to be independent of the total flow, the flow through the second section being saturated with oxygen. The apparatus thus provides a controlled concentration of oxygen. Temperature compensation is achieved by arranging for changes in the flow ratio caused by viscosity variations to compensate for variations in oxygen solubility.