GB2114093A - Cartridge-type tape cassettes - Google Patents

Abstract

The invention relates to cassettes having two spaced and rotatable reel hubs (2) with the tape (6) guided by rollers (4) from one reel hub to the other via a tape head (5). Due to various causes, including static and air build-up at the wind-on point the tape is liable to irregular wind-up onto the reel-hubs, which can lead to squeal or stretching of the tape. To eliminate, or at least substantially reduce the possibility of irregular wind-up, the cassette is characterised by guide rollers (7) the surface of each of which has flat faces (8) which are slanted at an angle with respect to the roller axis. In use the tape is made to flutter as it is wound onto a reel hub by a fluctuating motion imparted to it by the guide surface of the appropriate guide roller. Preferably two, diagonally opposite slanted faces (8) are provided, and flanges (9) are provided at the roller ends so that, in section, each roller is generally Z-shaped. <IMAGE>

Description

SPECIFICATION Cartridge-type tape cassettes This invention relates to tape cassettes, and more particularly to cartridge-type tape cassettes of the kind including guide rollers for guiding the tape from one reel hub to the other via a head pad.

In conventional tape cassettes such as shown in Figures 1 and 2 of the accompanying drawings, a magnetic tape 6 is connected between two spaced reel hubs 2, 2, which are rotatably mounted between two casing halves 1, 1, the tape run being guided across a head pad 5 by guide rollers 4, 4 spaced on each side of said head pad.

However, conventional tape cassettes have the drawback that the part of the tape being taken onto the tape-wound body is often liable to shift out of the winding plane of the tape-wound body, so as to cause irregular wind-up of the tape. It is thought that this is due to various causes, including the build-up of static in the tape.

Because of this irregular wind-up of the tape, the tape-wound body sometimes can come into contact with other parts of the cassette such as the casing, or reel hub flanges where provided, and thus cause the tape to squeel and/or stretch, or become distorted.

Referring to Figure 2, the left side, tape-wound body of the conventional cassette is shown to have risen up conically during tape wind-up, and to have come into contact with the upper flange 3 of its reel-hub. This is a common occurance and, as discussed above, it can lead to deformation and/or squeal of the tape,and moreover, wow and flutter.

Also, if a conventional thin tape for longplaying performance is used in the cassette, for example, C-90 or C-120, serious defects have occurred under the influence of static build-up, including cases where the tape has been folded completely over or folded in along its edges.

An object of the present invention is to obviate the drawback and defects of a conventional tape cassette discussed above by the arrangement which eliminates, or at least reduces to a minimum, irregular winding-up of the tape-wound body, with consequent improvement of the life and acoustic performance of the magnetic tape.

Another object of the present invention is to provide an arrangement for the cassette which prevents shifting of the winding plane of the tapewound body during winding-up of the tape.

According to the invention, the cassette is characterised in that the surface of each said guide roller is provided with flat faces which are set at an angle with respect to the axis of the roller, the arrangemenent being such-that, in use, the part of the tape being wound onto a reel hub is made to flutter, by a fluctuating motion imparted to the tape by the guide surface of the appropriate guide roller.

In order that the invention may be readily understood, and further features made apparent, one embodiment thereof will now be described in detail, with reference to the accompanying drawings, in which.~ Figure 1 is a plan view with one upper casing half removed showing the internal construction of a conventional tape cassette; Figure 2 is a cross-sectional view on the line Il-Il of Figure 1; Figure 3 is an enlarged front elevational view of a special guide roller for a cassette according to the present invention; Figure 4 is a side elevational view of the guide roller of Figure 3; and Figure 5 is a view similar to Figure 1 of said embodiment of a tape cassette according to the present invention.

Referring now to the drawings, Figure 1 shows a conventional cassette which has been recently developed, said cassette comprising two cooperating casing halves 1, 1 (one half of which has been removed for clarity) reel hubs 2, 2, two reel-hub flanges 3, 3, two guide rollers 4, 4, a pad 5, and the run of magnetic tape 6.

Referring now to Figure 5, and in accordance with the present invention, the conventional guide rollers 4, 4, are replaced with special guide rollers 7, 7 the guide surfaces of which are basically Zshape in section, as shown more clearly in Figures 3 and 4. In this embodiment, each Z-shape guide roller 7 is constituted by two flanges 9, 9 at each end of the roller section, 10 said roller section being of basically circular cross-section which, however, has two diametrically opposed flat faces 8, 8 set at a predetermined angle relative to the axis of the roller, which axis is defined by bearing pins 11,11.

As represented by chain-dotted lines in Figure 5, with the magnetic tape 6 wound around the reel hubs 2, 2 via the Z-shape guide rollers 7, 7, in use, due to the slanted faces 8, 8 of said rollers, the tape 6 is given a turbulent fluttering by the guide rollers 7, 7, which fluttering is particularly important in the advancing direction at the position just forward of where the tape is taken up by a reel hub 2. Therefore, even though the tape is taken up at low speed as in conventional cassettes, the air that tends to build-up between the part of the tape where it winds onto the tapewound body is driven out by the above-mentioned fluttering and, as a result, the tape-wound body does not tend to rise up, or be irregularly wound up, due to a shifting winding plane, as discussed above.In other words, the part of the tape being taken up onto the tape-wound body tends to be tightly and regularly taken up by the fluttering imparted to the tape by the appropriate roller 7, just before take up onto the tape-wound body.

Moreover, since, the diameter of each Z shaped roller 7 changes rapidly at its slanted faces 8, the tape runs around the roller in a fluctuating manner, which tends to prevent the generation of static.

Even in the case of a thin tape for long-playing performance, by using the special guide rollers 7, there is no tendency for such a tape to be folded over during running, or folded in along its edges, which in conventional cassettes can occur due to static.

As will be appreciated from the above, the present invention, although of simple construction, provides a significant technical effect.

Obviously, numerous modifications and variations of the present invention are possible within the scope of the appended Claims.

Claims (4)

Claims

1. A tape cassette of the kind comprising a casing in which two spaced reel hubs are rotatably mounted, between which the tape is connected, and guide rollers for guiding said tape from one reel hub to the other via a tape head, characterised in that the surface of each said guide roller is provided with flattened faces which are set at an angle with respect to the axis of the roller, the arrangement being such that, in use, the part of the tape being wound onto a reel hub is made to flutter, by a fluctuating motion imparted to the tape by the guide surface of the appropriate guide roller.

2. A tape cassette according to Claim 1, characterised in that two, diagonally opposite flat faces are provided and are set at the same predetermined angle with respect to said roller axis.

3. A tape cassette as claimed in Claim 2, characterised in that the ends of each guide roller are provided with flanges, the arrangement being such that, in section, each guide roller is of generally Z-shape.

4. A tape cassette constructed, arranged, and adapted for use substantially as hereinbefore described, and shown in, Figures 3 to 5 of the accompanying drawings.