Apparatus for controlling movement of a compact disk carousel and a compact disk insertion/extraction arm

Claim 1

For use in a compact disc storage and retrieval device having a carousel with a plurality of vertical storage locations for compact disks and an extraction arm for inserting and removing said compact disks to and from said storage locations, apparatus for controlling movement of said carousel and said extraction arm to facilitate said inserting and removing of said compact disks to and from said storage locations, comprising: (a) means for rotating said carousel; (b) a circular slotted track connected to said carousel, said slotted track having a plurality of equidistant slots for identifying said plurality of disk storage locations; (c) means for moving said extraction arm radially relative to said carousel to thereby insert and remove said compact disks to and from said storage locations; (d) a linear slotted track connected to said extraction arm, said linear slotted track also having a plurality of equidistant slots corresponding to various positions of said extraction arm relative to said carousel; (e) a pair of optical sensor means respectively mounted across said circular track and said linear track so that said slots pass therethrough upon movement of said carousel and extraction arm, respectively, wherein each of said optical sensor means detects passage of said slots therethrough and in response generates pulse signals, wherein said optical sensor means further comprises a plurality of optical interrupters each being of a predetermined width, said plurality of optical interrupters being spaced apart by a predetermined spacing of P(N+1/X), where P is the pitch of said slots, N is an integer greater than one, and X is the number of said optical interrupters, and where N is of sufficient magnitude to accommodate said predetermined width of each of said optical interrupters; (f) memory means for storing predetermined count values representative of predetermined storage locations of said carousel and predetermined various positions of said extractions arm relative to said carousel; and (g) circuit means connected to each of said pair of optical sensor means, said means for rotating said carousel, said means for moving said extraction arm, and said memory means, for counting said pulse signals in response to rotation of said carousel and movement of said extraction arm, respectively, and selectively disabling said means for rotating said carousel and said means for moving said extraction arm upon counting to said predetermined count values, whereby said carousel is accurately positioned to align said predetermined storage locations with said extraction arm and said extraction arm is accurately moved to said various positions relative to said carousel.