| 摘要 |
A cam assembly is disclosed which is used for the selection of different track positions for a magnetic tape head in a magnetic tape player/recorder. The tape track position of a magnetic tape head is determined by the position of a cam follower member which is selectively positioned with respect to a reference surface by selectively positioning a number of different diameter ball bearings between the cam follower member and the reference surface. Specifically, a solenoid actuated armature causes the linear movement of pawl members which in turn rotate a ratchet wheel member. The ratchet wheel member forms part of a cam apparatus that includes four ball bearings of different diameters. Sequential rotation of the ratchet member selectively positions ball bearings of different diameters between a non-rotatable reference surface and the cam follower member. Thus an accurate and inexpensive cam positioning mechanism is disclosed which uses precision ball bearings instead of an expensive cam having precisely formed surfaces to implement precise magnetic tape head position changes. |
