Photosensor block

Claim 1

A zero track sensor arrangement for a disk drive unit which includes a stationary section for receiving a disk for rotation thereon, said disk having a zero track prceeding a plurality of concentric other tracks arranged in radial progression on the disk, and a head mounted on a movable member for movement in a radial direction of a disk received on said stationary section, said zero track sensor being arranged to sense whether said head is centered in transducing relation with said zero track of the disk, comprising: a shutter member mounted to said movable member for movement along a path together with said head, a photosensor having a light emitting element and a light receiving element disposed in an opposing relationship to said light emitting element with a gap interposed therebetween to provide a beam of light from said light emitting to said light receiving element, and mounting means on said stationary section for mounting said photosensor in a position in which said shutter member can intercept the light beam from said light emitting to said light receiving element, said mounting means including a pair of parallel elastic members each having two opposite ends and a base member to which said elastic members are connected at respective one ends thereof, said photosensor being mounted at respective opposite ends of said elastic members, said photosensor, said elastic members, and said mounting means substantially forming four sides of a parallelepiped, said mounting means further including an adjusting member adjustably mounted on said base member for abutting engagement at an end thereof with one of said elastic members to adjust the position of said photosensor in a direction substantially along the path of said shutter member against an elastic force of said elastic members.