Abstract: In a spectrophotometer application where high speed positioning is critical, a galvanometer in conjunction with a microprocessor controlled hybrid digital/analog servo system is used to rotate a diffraction grating for wavelength selection. A table containing digital position information for all wavelengths is accessed by the microprocessor to perform wavelength changes. The use of the table permits the determination of grating position to yield a desired wavelength for a system where the axis of rotation does not intersect a point on the surface of the diffraction grating. That is, the diffraction grating can be rotated about an axis coinciding with its center of gravity.

Abstract: In an optical system having an optical element (such as a diffraction grating) mounted on a shaft which is to be affixed to the shaft of a driver such as a galvanometer, a collet assembly is used to couple the two shafts together so as to maintain the two shafts coaxially relative to each other.

Abstract: An improved mounting for a rotating diffraction grating assembly as used in a spectrophotometer directly connects the grating to the galvanometer that rotates the grating. The galvanometer is gimbally mounted on a plate so that its position, and that of the grating, can be adjusted so that the plane of dispersion of the grating passes through a desired point when the grating is rotated.

Abstract: An improved agitator for a coin hopper having a rotatable pinwheel includes a hub mounted to the pinwheel and a plurality of elongated, longitudinally resilient blades projecting radially outward from the hub. The hub is preferably made of neoprene or other flexible material, and is mounted to the center of the plate so that the two rotate together. The blades are preferably made of spring steel or similar material and are not themselves attached to the pinwheel, but are embedded in the hub. The blades have hard, low friction surfaces, and longitudinally yield upon impact with the coins in the hopper and act to stir the coins and urge them into coin receiving slots on the pinwheel.