Tape entrainment device with a movable entrainment roller

Claim 1

In a magnetic recorder of the type including: a support; two spools mounted to rotate in the same plane on the support about two respective parallel axes; a tape encircling at least one of the spools, the tape and the two spools on which the tape can be wound forming two reels connected by an accessible portion of tape; a tape drive roller rotating in the same plane as the reels and tangentially to the peripheries thereof; and an endless belt, which is taut and able to withstand some stretching, passing between the roller and the reels and engaging an arc of the periphery of each of these reels in order to ensure tensioning of the accessible portion of tape; means for driving said tape comprising: a rotatably driven disc rigidly attached to and coaxial with said tape drive roller, said disc being tangential to and driven along its periphery by a drive disc, said drive disc having an axis of rotation situated on the same side of a line joining said spool axes as is said tape drive roller, said driven disc being arranged such that during winding off of said tape from one reel to the other said driven disc is forced mechanically to shift its position relative to the support along a circular path, whose axis is defined by the axis of said drive disc, said mechanical shifting of said driven disc being constrained by the movement of the periphery of the driven disc on said drive disc and by the force applied by the belt to said tape drive roller in the direction of the reels so as to cause said tape drive roller to follow a path approximating said circular path and to thereby frictionally drive the tape by means of said belt against which said tape drive roller bears.