GB2272424A - Magnetic tape cassette : recording control slider - Google Patents

Abstract

A cassette of magnetic tape, e.g. video tape, has an anti-recording hole 22 in a side wall, and an internal flat slider 24 to close/open the hole. The slider slides in internal grooves 34, 36, has hand knob 32 projecting through the hole, and has lug 30 on an elastic finger to engage recesses 38, 40 to retain the slider in an open or closed position. <IMAGE>

Description

MAGNETIC TAPE CASSETTE WITH AN IMPROVED RECORD CONTROL SLIDER The present invention pertains to a magnetic tape cassette for use in a tape recorder and, more particularly, is directed to a magnetic tape cassette having an antirecording hole provided on a longitudinal side wall thereof and a record control slider received within the tape cassette for selectively closing and opening the antirecording hole.

A magnetic tape cassette has been extensively used to store various audio and/or video signals, the recording operation of which is carried out by means OI, e.g., a tape recorder and the like. In such a prior art magnetic tape cassette, the signals recorded on the tape might be inadvertently erased or replaced with new signals if no safeguard is provided.

To keep the recorded signals safe from erasure, the state-o-art magnetic tape cassette is usually provided with an antirecording or erasure preventing hole which may be closed by a suitable closure member. As its name implies, the antirecording hole is adapted to preclude the possibility of either overrecording new signals on the magnetic tape or erasing the recorded signals in error. Once the antirecording hole is closed by the closure member, it becomes possible to erase the recorded signals from the magnetic tape.

Whether the antirecording hole is kept open or closed may be detected by a sensor device of the tape recorder. The sensor device is designed to render the tape recorder inoperative in its record mode when it detects the antirecording hole. On the other hand, the recording operation of the tape recorder is allowed to occur when the sensor device fails to detect the presence of the antirecording hole.

A variety of closure members is known in the art that may selectively close and open the antirecording hole. U.S.

Patent No. 4,496,999 to M. Espin discloses a videotape cassette having a three-sided spring clip which is adapted to resiliently engage outer surfaces of the cassette housing for sliding movement into and out of a covering position of the antirecording hole. The spring clip is provided with a leg which engages with a so-called "side-loading" groove of the tape cassette in a slidable manner. Although the spring clip taught in the '999 patent is simple in structure, it is possible that the spring clip might be detached from the tape cassette during the course of packaging, transporting and using the magnetic tape cassette. Another disadvantage of the prior art device is that the spring clip may interfere with parts or components of the tape recorder as the magentic tape cassette is being loaded into or unloaded from the tape recorder.

Japanese Utility Model Publication No. Sho 63-19976 teaches a magnetic tape cassette having a generally C-shaped plug which may be removably inserted into an antirecording recess of the tape cassette. The plug has opposite closed and open ends; and is normally inserted into the antirecording recess so that its open end can be exposed to the outside, thereby keeping the recess open. If the user desires to overrecord the magnetic tape, the plug has to be inserted in the reverse direction so that the closed end thereof may cover the recess. With the removable plug described above, however, it may be quite cumbersome for the user to remove the plug out of the recess and then reinsert it in the reverse direction.

The present invention seeks to provide a magnetic tape cassette which is able to safeguard video signals recorded on the tape against overrecording or inadvertent erasure, and to provide a magnetic tape cassette having a record control slider which can be readily shifted from an open position to a closed position and vice versa in a reliable manner.

In accordance with the invention, there is provided a magnetic tape cassette which comprises: a housing having an antirecording hole on a longitudinal side wall thereof; a slider mounted inside the housing for selectively closing and opening the antirecording hole as it moves from a first open position to a second closed position and vice versa, the slider having a flat body, an elastic finger integrally formed with the body at its proximal end and a knob projecting outwardly from the body through the antirecording hole, the finger including a positioning lug formed at its free end; means for guiding the slider as it slides between the first and the second positions;# and retainer means for cooperating with the positioning lug to retain the slider at one of the first and the second positions.

The above and other objects and features of the present invention will become apparent from the following description of preferred embodiment taken in conjunction with the accompanying drawings, in which: Fig. 1 is a schematic perspective view of the videotape cassette incorporating a record control slider in accordance with the invention, with the slider lying in a first open position; Fig. 2 is a perspective view showing the slider of the present invention on an enlarged scale; Fig. 3 is a cross-sectional view taken along line III-III of Fig. 1; Fig. 4 is a cross-sectional view taken along line IV-IV of Fig. 3, illustrating the slider that remains in the first position uncovering the hole; and Fig. 5 is a cross-sectional view similar to Fig. , bu showing the slider that lies in the second position cover~:.

the hole.

Referring first to Fig. 1, there is shown by way o.

illustration a videotape cassette embodying the invention, generally designated by reference numeral 10, which is intended for use in a video cassette recorder usually referred to as VCR. As shown, the videotape cassette 10 is provided with a lower and an upper cassette casings 12 and lt that may be combined together to form a rectangular box-shaped housing or cartridge for receiving a pair of rotatable reels 16 on which a length of videotape 18 is wound in the form of a roll.

Provided on a longitudinal side wall 20 of the lower casing 12 is an antirecording hole 22 which coacts with a sensor device(not shown)of the VCR. It is known in the art that the sensor device serves to inhibit the recording operation of the VCR when it detects the presence of the antirecording hole.

As indicated by a dot line in Fig. 1, a record control slider 24 of a generally rectangular shape is mounted inside the side wall 20 of the cassette 10 in a manner that it can slide along a limited length of the side wall 20. The slider 24 consists of a flat body 28, an elastic finger 26 integrally formed with the body 28 at its proximal end and a knob 3.

vertically projecting from the body 28, as best illustrated Figs. 2 and 3.

The elastic finger 26 is coplanar with the body 28 of the slider 24 and extends in parallel to the body 28 with an adequate spacing therefrom. At the free end of the elastic finger 26, there is provided a positioning lug 30 of a round shape that functions to restrain the sliding movement of the slider 24 as set forth hereinbelow. As clearly shown in -Fig.

3, an upper channel or groove 36 is formed on the top plate of the upper casing 14 to accommodate the top edge of the slider 24 whereas a lower channel or groove 34 is provided on the bottom plate of the lower casing 12 to receive the bottom edge of the elastic finger 26. The upper and the lower channels 36 and 34 serve as a guide means for guiding the movement of the slider 24 from a first open position to a second closed position and vice versa. When the slider 24 is assembled in position, the knob 32 thereof is designed to project outwardly through the antirecording hole 22 so that the user may grip it by hand to apply manual sliding force thereto.

Referring to Figs. 4 and 5, it can be appreciated that a first and a second recesses 38 and 40 are disposed on the lower channel 34. These recesses 38 and 40 are adapted to cooperate with the positioning lug 30 of the slider 24 to thereby retain the slider 24 in either ol the first position or the second position against any inadvertent displacement.

Thus the spacing between the first recess 38 and the second recess 40 should preferably be equal to the length of the antirecording hole 22 to ensure a complete closing or opening of the hole 22.

In operation, if the slider 24 remains at the leftmost position, i.e., first position, as illustrated in Fig. a, the positioning lug 30 will engage with the first recess 38 to restrain the movement of the slider 24. Under that condition, the antirecording hole 22 is kept open, thereby inhibiting the recording operation of the VCR or tape recorder. As the slider 24 moves to the rightmost position, i.e., second position by the user's manual force, the positioning lug 30 comes into engagement with the second recess 40 as depicted in Fig. 5. In response, the antirecording hole 22 is completely closed by the slider 24, thereby allowing the VCR to carry out its recording operation. As a result, when the slider 24 is in the second position, it is possible to either overrecord new signals onto the magnetic tape or to erase the recorded signals from the tape.

Claims (4)

1. A magnetic tape cassette including a housing having an antirecording hole on a longitudinal side wall thereof, which comprises: a slider mounted inside the housing for selectively closing and opening the antirecording hole as it moves from a first open position to a second closed position and vice versa, the slider having a flat body, an elastic finger integrally formed with the body at its proximal end and a knob projecting outwardly from the body through the antirecording hole, the finger including a positioning lug formed at its free end; means for guiding the slider as it slides between the first and the second positions; and retainer means for cooperating with the positioning lug to retain the slider at one of the first and the second positions.

2. A magnetic tape cassette according to claim l, wherein the guide means comprises an upper channel formed on a top plate of the cassette housing to extend along a limited length of the longitudinal side wall and a lower channel provided on a bottom plate of the cassette housing to extend in the same direction as that of the upper channel.

3. A magnetic tape cassette according to claim 2, wherein the retainer means includes a first and a second recesses each formed on the lower channel at a spacing substantially equal to the length of the antirecording hole, the first recess arranged to engage with the positioning lug when the slider is in the first open position, the second recess arranged to engage with the positioning lug when the slider is in the second closed position.

4. A magnetic tape cassette substantially as described herein with reference to the accompanying drawings.