| 摘要 |
<p>A tension control device, particularly for an apparatus recording and/or reproducing video signals on a tape which is wound on and extends between supply and take-up reels, includes a pivoted tension control arm urged by a tensioning spring against a run of the tape between the reels for detecting the tape tension and correspondingly controlling a brake resisting rotation of the supply reel so as to maintain the tape tension at a level determined by the spring force, and the spring force is made adjustable for varying the tape tension which is to be maintained by connecting the tensioning spring to a movable anchor member which is substantially counter-balanced, for example, by another spring acting on the anchor member in opposition to the tensioning spring. Movements of the anchor member for adjusting the force of the tensioning spring are effected by a manually actuable control element preferably having an irreversible coupling to the anchor member which provides a substantial mechanical advantage, for example, in the form of a cam member turnable with the control element and engaged by a cam follower on the movable anchor member.</p> |
