Video recorder with static head assembly - uses one head for each direction of tape movement

摘要

In order to simplify the mechanics of video recorders an arrangement is used where the video tape which is multi tracked is moved at the full speed of about 20 m/sec as many times forward and backwards as there are recording tracks. The difficulty of obtaining a near-instantaneous inversion of tape movement is solved by the provision of two heads one for each direction of tape movement mutually offset by one track pitch. The capstan wheels are hollow and tiny holes pass air suction or air pressure to the active surface enabling a rapid change-over of pulling action. The capstans rotate in opposite directions. Acceleration forces are buffered by spring loaded idler rollers. The system functions correctly when during the transitional period the tape opposite one head passes at the same velocity in one direction as the tape opposite the other head passes in the opposite direction. During this phase which lasts only a very short time the electronic connection to the heads is switched over, after which the tape at the disconnected head looses its capstan drive, and unidirectional tape speed is restored.