Apparatus for moving tape incrementally past a recording head

Claim 1

An incremental recording apparatus for moving tape incrementally past a recording head, comprising: a rotatable capstan shaft against which tape is pressed, the rotation of the capstan shaft serving to advance the tape; a continuously rotated flywheel supported about said capstan shaft, said flywheel having, at one end thereof, a reduced diameter shoulder portion coaxial with said Capstan shaft; a drive collar affixed to said capstan shaft and having a reduced diameter shoulder portion coaxial with said capstan shaft, said flywheel shoulder and drive collar shoulder being of substantially the same diameter and adjacent each other; a coiled spring coaxially received about said capstan shoulder and said drive collar shoulder, the normal internal diameter of the spring being slightly smaller than the external diameter of said flywheel shoulder and said drive collar shoulder, the direction of rotation of said flywheel tending to tighten said spring about said flywheel shoulder and said drive collar shoulder, said spring having a radially extending tang at the end thereof received on said flywheel shoulder; a tubular ratchet member coaxially received about and externally of said spring, the interior diameter of said ratchet member being slightly larger than the external diameter of said spring, said ratchet member having a slot therein receiving said tang of said spring whereby said spring and said ratchet member are rotationally interlocked; a ratchet release bar movably supported adjacent said ratchet member and movable between a first and a second position, and arranged such that in said first position said release bar engages said ratchet member preventing the rotation thereof, and in said second position said release bar is removed from said ratchet member and permits the rotation of said ratchet member; and means of selectably moving said ratchet release bar between said first and second positions.