Guide elements for magnetic tapes wound or to be wound in the form of packs on flangeless spools

Abstract

Guide elements for magnetic tapes wound or to be wound in the form of packs on flangeless spools, the guide elements being movable in the plane of rotation of the packs. At least part of the guide elements is located between the pack and the outermost winding and thus constantly guides the tape as it is wound or unwound, resulting in optimal tape guidance and consequently in a stable and accurate winding on the spool.

We claim: 
     
       1. In a magnetic tape assembly, the combination comprising: a pair of tape-supporting flangeless spools rotatable to unwind tape off a pack on one spool and wind tape onto a pack on the other spool, said tape passing between the packs around guide means in the form of a loop, and   b. at least one guide element movable substantially radially to one of said spools and in the plane of rotation of said spools, at least part of said guide element being arranged between the pack and the outermost winding generally at a tangent to said pack, having a guide face which is substantially flat longitudinally of said outermost winding, thereby providing continuous surface contact over a substantial length of said face between said face and the inside of said outermost winding when said tape is in motion, having adjacent that end of the guide face at which said outermost winding merges with said pack, a margin which is at least as close to the pack as said face so that said outermost winding is guided smoothly and virtually tangentially to said pack at said margin, and having guide flanges extending outwardly above and below said outermost winding.   
     
     
       2. The combination of claim 1 wherein said guide element is slidable in the plane of rotation of the spools. 
     
     
       3. The combination of claim 2 wherein said slidably mounted member has a C profile when viewed from the side. 
     
     
       4. The combination of claim 1 wherein said guide element is a lever pivotable in the plane of rotation of the spools. 
     
     
       5. The combination of claim 4 wherein said guide flanges are provided at the free end of said lever, and wherein said end margin is provided on said free end of the lever at a point near the line passing through the center of the spools. 
     
     
       6. The combination of claim 4 wherein said assembly includes idler rolls and wherein said lever is pivotally mounted on a pin inside the loop of tape near one of said idler rolls. 
     
     
       7. The combination of claim 4 wherein said assembly includes pins disposed inside said loop and wherein said lever is pivotally mounted on one of said pins, the end of said lever at which it is pivotally mounted being used as a guide means for said loop of tape. 
     
     
       8. The combination of claim 4, wherein said lever has a base portion and a free end portion; wherein there are provided means for pivotally mounting said base portion outside said loop; wherein said free end portion of the lever, which has said flat guide face, said margin and said flanges, is offset from said base portion; and wherein at the point of offset a slot is provided in said lever, through which said outermost winding passes. 
     
     
       9. The combination of claim 4 wherein the free end of said lever has an offset pin disposed outwardly of said tape and spaced from said margin to provide a slot for accommodating said outermost winding, the width of said slot being less than that of said tape. 
     
     
       10. The combination of claim 1 wherein said guide element or at least said part thereof is of generally arcuate shape and wherein the thickness of said arcuate element or part tapers toward said margin. 
     
     
       11. In a magnetic tape cassette, the combination comprising: a. a pair of tape-supporting flangeless spools rotatable to unwind tape off a pack on one spool and wind tape onto a pack on the other spool, said tape passing between the packs in the form of a loop in the course of which said tape comes into contact with magnetic transducer means penetrating through openings in the cassette, and   b. a first guide lever provided for the pack on the winding spool and a second guide lever provided for the pack on the unwinding spool, each of said guide levers being mounted for pivotal movement substantially radially to the corresponding one of said spools and in the plane of rotation of said spools, at least part of each of said guide levers being arranged between the corresponding pack and its outermost winding generally at a tangent to the pack, having a guide face which is substantially flat longitudinally of said outermost winding, thereby providing continuous surface contact over a substantial length of said face between said face and the inside of said outermost winding when the tape is in motion, having adjacent that end of the guide face at which said outermost winding merges with said pack, a margin which is at least as close to the pack as said face, and having guide flanges extending above and below, respectively, said outermost winding, said guide face, margin and guide flanges being of a configuration such as to stiffen said tape before initial contact with the pack of said winding spool and after ultimate contact with the pack on said unwinding spool, and to freshly orient each of the unwound windings in an aligned position relative to said transducer means and each of the windings to be wound in its proper position on the pack regardless of how the side surfaces of the pack happen to be shaped. .Iadd. 12. In a magnetic tape cassette, the combination comprising:   a. a pair of tape-supporting flangeless spools rotatable to unwind tape off a pack on one spool and wind tape onto a pack on the other spool, said tape passing between the packs in the form of a loop in the course of which said tape comes into contact with magnetic transducer means penetrating through openings in the cassette, and   b. a first guide element provided for the pack on the winding spool and a second guide element provided for the pack on the unwinding spool, each of said guide elements being mounted for displacement towards or away from the corresponding one of said spools and in the plane of rotation of said spools, and at least part of each of said guide elements being arranged between the corresponding pack and its outermost winding generally at a tangent to the pack, having a tape support portion of an effective length such as to provide, when the tape is in motion, guidance for said outermost winding, on the inside thereof, over a substantially flat longitudinal path regardless of the diameter of the corresponding pack, and having guide flanges extending above and below, respectively, said outermost winding, said tape support portion and guide flanges being of a configuration such as to stiffen said tape before initial contact with the pack on said winding spool and after ultimate contact with the pack on said unwinding spool, and to freshly orient each of the unwound windings in an aligned position relative to said transducer means and each of the windings to be wound in its proper position on the pack. .Iaddend..Iadd. 13. In a magnetic tape recorder, the combination as claimed in claim 12, wherein each of said guide elements is mounted for bodily movement along a curved path such that, as said element is displaced in response to the unwinding or winding action of the tape, the corresponding tape support portion remains oriented in a plane substantially tangential to said pack. .Iaddend.