Compact disc counter arranged to minimize counting errors having a pair of beams and a pulse counting means

Apparatus for counting compact discs, each of which is formed with a central boss and an outer portion, said discs being arranged in a stack on a vertical spindle having a base with normal gaps formed by said bosses between outer portions of adjacent discs including in combination

• means for forming a pair of beams of radiation, means for spacing said beams vertically by a distance substantially equal to the distance between a pair of adjacent normal gaps between discs and greater than the vertical extent of a normal gap of said stack,
• radiation detecting means,
• means for mounting said detecting means in operative relationship to said beam producing means and with a space therebetween,
• a support for receiving a spindle base,
• means for mounting said support for vertical movement of a stack carried by said spindle base along a path through said space between an upper rest position and a lower home position,
• said path being located relative to said beam producing means such that said beams scan said gaps at the outer portions of said discs,
• energizable means for driving said support,
• and means responsive to said detecting means for producing a count of the number of discs in said stack.