Tape cassette index system

Claim 2

In a system comprising at least one reel mounted in fixed axial relation in a housing, and constructed in response to driving means to rotate in one direction or the other for rolling up or unrolling a length of tape, said reel provided with a hub, an indexing system for indicating the precise position of information recorded on the said tape, said indexing system comprising: a fixed rim integral with a face of said housing, substantially concentric with said reel and having a central opening at least large enough to accommodate the hub of said reel, an annular disk rotatably accommodated within said rim and constructed for slight lateral movement relative to the axis of said rim, said disk having a circular central opening slightly larger than the outer diameter of said hub and an outer periphery of slightly smaller diameter than the inner diameter of said fixed rim, resilient bearing means coupled in fixed relation to said hub and constructed to bear against the central opening of said annular disk and to move slidably therearound in response to rotation of said hub about its longitudinal axis, said resilient bearing means constructed to cause the outer periphery of said disk to rotate oppositely in progressively meshed relation against an interior surface of said fixed rim, said annular disk having a radial slot, indicator means comprising a body portion and a projection substantially normal to said body portion, the body portion of said indicator means constructed to move slidably in said slot upon rotation of said disk, an indicator face disposed in a plane substantially parallel to the plane of said fixed rim and constructed to be frictionally maintained in fixed angular relationship to said fixed rim upon rotation of said disk, said projection constrained upon rotation of said disk to move in a spiral path adjacent a major under surface of said indicator face whereby the position of said projection is visible on said indicator face to indicate the degree of rotation of said disk relative to said fixed rim.

Claim 3

The combination in accordance with claim 1 wherein said face comprises a spiral groove commencing at a position adjacent to said fixed rim and extending inwardly along said plane substantially centered on the central opening of said housing, and wherein said projection engages and rides in said spiral groove upon rotation of said annular disk, the position of said projection being visible on said indicator face to indicate the degree of rotation of said disk relative to said fixed rim.

Claim 4

The combination in accordance with claim 1 wherein said resilient bearing means constructed to bear against said central opening of said disk comprises a spring.

Claim 5

The combination in accordance with claim 3 wherein said fixed rim has inwardly directed teeth, and said annular disk has peripheral teeth slightly less in number than the teeth of said fixed rim, and portions of said teeth are held in the progressively meshing relation by the compression of said spring, causing a backward rotation of said annular disk relative to said fixed rim at a rate which is related to the rate of rotation of said reel by the gear ratio between said fixed rim and said annular disk.

Claim 6

The combination in accordance with claim 2 wherein the groove in which said projection rides is formed on the undersurface of said indicator face, and the portion on the outersurface of saId indicator face conforming to the path of said groove is transparent, and the portion of said outer face adjacent said transparent portion comprises an erasable medium constructed to receive visible marks corresponding to audio recording points on said tape.

Claim 7

The combination in accordance with claim 5 wherein said indicator face comprises a rimmed cover constructed to snap fit over said fixed rim in concentric relation thereto, said indicator face being rotatably movable manually relative to said fixed rim for synchronizing markings on said indicator face with audio indications at preselected positions on said tape.

Claim 8

The combination in accordance with claim 3 wherein said resilient bearing means coupled in fixed relation to said hub and constructed to bear against the central opening of said annular disk comprises a leaf spring.

Claim 9

The combination in accordance with claim 4 wherein the length of said spiral groove and the overall length of said tape is a substantially fixed function of the gear ratio between the teeth of said fixed rim and said annular disk, thereby determining the degree of resolution of said indexing system.

Claim 10

In a system comprising a magnetic tape cassette comprising a pair of reels mounted with their axes fixed in spaced apart relation in a housing, the said reels equipped with hubs respectively constructed for engagement with a pair of spindles of a magnetic tape recording and reproducing machine for unrolling a length of magnetic tape from one said reel and simultaneously rolling up a corresponding length of magnetic tape on the other said reel, an indexing system for indicating the precise position of information recorded on said tape, said indexing system comprising a pair of fixed rims disposed in off-set relation on each of the two opposite major surfaces of said housing, each said rim substantially concentric with one of said reels and having a central opening at least large enough to accommodate the hub of said reel, an annular disk accommodated within each of said rims having a circular central opening slightly larger than the outer diameter of said hub and an outer peripheral diameter slightly smaller than the inner diameter of said rim, resilient bearing means coupled in fixed relation to each of said hubs and constructed to bear against the respective central openings of said annular disks, and to move slidably therearound in response to rotation of said respective hub about its longitudinal axis, said resilient bearing means constructed to cause the outer periphery of each said disk to rotate oppositely in progressively meshed relation against the inner periphery of each said fixed rim, each said annular disk having a radial slot, a pair of indicator means, each comprising a body portion and a projection substantially normal to said body portion, the body portion of each said indicator means constructed to move slidably in a respective one of the slots in said rotating disks, a pair of indicating faces respectively disposed in planes substantially parallel to said fixed rims adjacent opposite major surfaces of said cassette housing, each said projection respectively constrained upon rotation of the associated disk to move in a spiral path relative to the surface of a respective one of said indicating faces, whereby the position of each of said projections is visible on the respective indicator face to indicate the degree of rotation of the associated disk relative to its fixed rim.

Claim 11

In a system comprising a magnetic tape cassette comprising a pair of reels mounted with their axes fixed in spaced apart relation in a housing, the said reels equipped with hubs respectively constructed for engagement with a pair of spindles of a magnetic tape recording and reproducing machine for unrolling a length of magnetic tape from one said reel and simultaneously rolling up a corresponding length of magnetic tape on the other said reel, an indexing system for indicating the precise position of information recorded on said tape, said indexing system comprising a pair of fixed rims disposed in off-set relation on each of the two opposite major surfaces of said housing, each said rim substantially concentric with one of said reels and having a central opening at least large enough to accommodate the hub of said reel, an annular disk accommodated within each of said rims having a circular central opening slightly larger than the outer diameter of said hub and an outer peripheral diameter slightly smaller than the inner diameter of said rim, resilient bearing means coupled in fixed relation to each of said hubs and constructed to bear against the respective central openings of said annular disks, and to move slidably therearound in response to rotation of said respective hub about its longitudinal axis, said resilient bearing means constructed to cause the outer periphery of each said disk to rotate oppositely in progressively meshed relation against the inner periphery of each said fixed rim, each said annular disk having a radial slot, a pair of indicator means, each comprising a body portion and a projection substantially normal to said body portion, the body portion of each said indicator means constructed to move slidably in a respective one of the slots in said rotating disks, a pair of indicating faces respectively disposed in planes substantially parallel to said fixed rims adjacent opposite major surfaces of said cassette housing, each said projection respectively constrained upon rotation of the associated disk to move in a spiral path relative to the surface of a respective one of said indicating faces, whereby the position of each of said projections is visible on the respective indicator face to indicate the degree of rotation of the associated disk relative to its fixed rim.

Claim 12

The combination in accordance with claim 9 wherein each said resilient bearing means constructed to bear against the edge of the central openings of each of said disks comprises a spring.

Claim 13

The combination in accordance with claim 10 wherein the indicator faces adjacent opposite major surfaces of said housing each comprise an annulus substantially concentric with the axis of a respective one of said reels, and each constructed to be maintained in fixed angular relationship to a respEctive one of said rims upon rotation of said reels, each said annulus including a spiral groove commencing at a position adjacent the outer edge thereof and terminating at a position adjacent the central opening thereof, and each said projection engaging, and upon rotation of the respective annular disks, riding in its corresponding spiral groove, the position of each said projection in said spiral groove being respectively visible on the corresponding one of said indicator faces to indicate the degree of rotation of each of said disks relative to its respective rim.

Claim 14

The combination in accordance with claim 11 wherein each said outer rim has inwardly directed teeth, and said annular disk has peripheral teeth slightly less in number than the teeth of said fixed rim, and said teeth are held in progressively meshing relation by the compression of said spring, causing a backward rotation of each of said annular disks relative to its respective fixed rim at a rate which is related to the rate of rotation of said reels by the gear ratio between each said fixed rim and its respective annular disk.

Claim 15

The combination in accordance with claim 11 wherein the groove in which each said projection rides is formed on the undersurface of each of said indicator faces, the portion of the outer face of each corresponding to the path of the respective groove being transparent, and the portion of each outer face adjacent said transparent portion comprising a surface constructed to receive visible marks of an erasable or removable medium.

Claim 18

The method in accordance with claim 14 which comprises rigidly coupling a leaf spring to the hub of said reel for continuously bearing in slidable relation on the inner opening of said disk in coordination with the rotation of said hub.

Claim 19

The method in accordance with claim 14 which comprises providing said fixed rim with a given number of internally directed teeth, and said fixed annular disk with a slightly smaller number of externally directed teeth, and operating said annular disk relative to said rim as a pinion gear rolling against an internal ring gear.

Claim 20

The method in accordance with claim 14 which comprises constructing said indicator face of plastic in the form of a rimmed cap which is snap-fitted over fixed rim, said spiral groove being formed on the undersurface of said face, the portion of said outer indicator face conforming to said groove being of transparent plastic, and the portion of said outer indicator face adjacent and between said transparent portions being textured to receive erasable markings corresponding to recorded audio signals on said tape.