DE1549132A1 - Arrangement for driving magnetic tapes - Google Patents

Description

Anordnuncf for driving Macinetbändern The invention relates to an arrangement for driving magnetic tapes oder.anderen band-shaped information carriers with defined Vorschubgeachwindigkeito wherein the speed bestimmände drive roller, the magnetic tape without slippage transported only by sufficiently large wrapping und'ohne additional Andruckmaßnahmen, It is known and customary, To regulate the feed speed of magnetic tapes at the so-called "control point" by means of a rotating roller (usually called a "sound roller" in devices for acoustic recordings). A rubber roller is generally used to achieve sufficient entrainment, which presses the tape against the drive roller.

The practical advantage, which is mainly to be sought in the simplicity of such arrangements, is - as is known - faced with serious disadvantages. The speed difference depends, among other things, on the pressure of the roller and the elastic properties of the covering. It is therefore undefined within the limits in which the pressure force fluctuates and the blasticity properties can change - for example due to aging.

The use of a pressure roller has the further disadvantage that lone on the surface of the tape sedentary 8 # deaf particles when passing the control point rolled-and then no longer removed with simple action can be.

A major disadvantage of all drive systems with a pressure roller is also the inevitable high load on the drive roller bearings. Experience has shown that the motors driving the roller must be considerably overdimensioned - approximately a few times over - if the same degree of uniformity in the rotation speed is to be achieved that would result automatically without the high bearing load.

In order to get out of the way of the described difficulties, drives have already been proposed and used, especially for high-precision drives, which can do without rubber pressure rollers. Generates negative pressures in hollow and perforated drive rollers, which lead to sufficient adhesion of the tape to the roller even if no other pressure measure is used. However, drives are also known in which the slip-free entrainment is achieved by means of a very large wrap around the roller by the belt ( e.g. 180 ° and more).

This genus of 1, the invention lagnetband run Werkene to * of the arrangement according belongs has in the previously known embodiments, as many faults which are due to the cumbersome operation, on that their however, in spite of the principle advantages, a resounding Success was denied.

As in practice particularly harmful to the cumbersome loading and unloading of the tape that results when the # .ntriebeiwalze in the interest of a sufficient reliability, eg must be wrapped with 270 0 proved.

Another practical disadvantage is the behavior of such drives with fast forward and backward movement : If one does not want to let the belt slide over the control roller every time it is fast running by applying increased winding forces - a process that is necessary because of the high wear on the belt and roller in the Praxis is ruled out - then it would have to be lifted off the control roller every time it runs quickly and put back in again in case of operation. To avoid these circumstances, couplings have been proposed by means of which the control roller can be uncoupled from the drive motor or the flywheel at high speed. Manually operated lifting devices have also been implemented which lift the belt off the control roller when running at high speed .

However, none of these known arrangements avoid the tuerst main disadvantage described, namely the cumbersome insertion or removal of the magnetic tape at the beginning and end of a recording.

The arrangement according to the invention, which is shown schematically in Figure 1 , avoids all the disadvantages described and represents a synthesis of the advantages of the conventional drive system with pressure roller and the drive system without pressure roller :-( 1) is the magnetic tape ( or other information carrier) that is on the left Coming from the supply reel Via the deflection roller (2) past the magnetic heads (3) via the further roller (4) onto the take-up reel (right) is inserted into the drive in the usual way, approximately in a straight line.

In this state, the drive is in the rest position and is ready for fast rewinding (forward or reverse). (6) represents the speed-determining, driven transport roller, which is not touched by the belt in the rest or high-speed position.

For operation at a defined speed, according to claim 1 of the invention - for example by pressing a button - a further deflection roller (5), which is arranged pivotably on a circular path around the drive roller (6) , is moved from the starting position (A) to the end position (B ) emotional. In this way, the wrapping of the drive roller (6) required to take the tape along is achieved. The dashed line (7) shows the movement of the belt in this operating position. When switching to "stop" or "fast run". the roller (5) runs back into the starting position (A) . With a -.- licking force of the 7th reel spool that is maintained for the duration of the return, it picks up the resulting tape loop and the tape, which is again in the 7 # initial position (1) , can easily be removed from your drive.

In one embodiment of the invention, the pivoting movement of the roller (5) between its two end positions (It'i and B) is carried out by a servomotor, with automatically acting devices, for example end contacts, the rl, in-and .7. # unhooking the as well as the l #, 'iclitungsunüzelir after reaching the end positions.

The motorized drive offers, among other things, the additional advantage of remote control of the drive.

In a further embodiment of the invention is finally to claim 3 as a servomotor existing in the drive belt driving motors with used.

This Ausführungsforni allows the structure to be relatively smaller Drives in which the required amount of components is then noticeable can be reduced.

Claims (1)

Claims 1.) 2.nordnung to AIntrieb of Elragnetbändern or other band-shaped Infon - iationstr - '#, like by means of the speed determined with a defined feed velocity l'# ,. ntriebswal - e, the * in Detriebsfall so far from, tape it is wrapped around that its slip-free joint is guaranteed even without additional pressure measures, characterized by the fact that an upright roller (5) , arranged around the internal drive shaft (6 ), can be moved in the rest position of the drive Position (A) is so that the BE-nd according to the line (1) can be inserted without touching the Jalzr-, (6) and that after pressing a button, for example, the roller (5), for example on a semicircle, sbahn swivels into position (B) and the belt now wraps around the roller (6) according to the line (7) as largely as is necessary for a slip-free entrainment, whereby after pressing another button, for example, the roller (5) back to the starting position (4 - * # -) closed rüchschwenkt and the tape by the Wichel torque of the le back into the original gehl. (1) is stretched. 2.) 771 arrangement according to claim 1, characterized in that for pivoting the roller (51 in its end positions (A) and (B) a servomotor actuated by a button, for example, is used, with automatic devices such as EndkontallZte the one and cause disengagement and the direction reversal of the pivot arm, the drive after reaching the end positions 3) assembly according to claim 1 and 2, characterized in that one of the existing in-band Lzufwerk drive motors is also used as the actuator -..