GB1581809A

GB1581809A - Apparatus for crasing

Info

Publication number: GB1581809A
Application number: GB1464178A
Authority: GB
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 1977-04-14
Filing date: 1978-04-13
Publication date: 1980-12-17
Also published as: FR2387490A1; NL7801721A; DE2716587A1

Description

(54) APPARATUS FOR ERASING (71) We, SIEMENS AKTIENGESELLSCHAFT, a German company, of Berlin and Munich, Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The invention relates to apparatus for erasing information recorded on tapes of taped cassettes.

According to the present invention there is provided apparatus for erasing information recorded on tape of a tape cassette comprising: means for generating a magnetic field; and a holder for holding both reels of a magnetic tape cassette in said magnetic field; wherein one of said holder and said magnetic field is rotatable relative to the other from a first to a second position, through an angle of rotation of substantially 90 , about an axis extending substantially perpendicularly to the magnetic field lines generated in the region of a tape when in said holder, the apparatus being arranged in such a way that relative rotation of said one from the first to the second position substantially erases information recorded on tape on both reels of the tape cassette.

Relative rotation of the holder in the field from the second to the first position is preferably possible, either by relative rotation through an angle of substantially 360" about the axis mentioned above or alternatively by reverse rotation from the second to the first position.

The first and second positions may be defined by means of a grip provided on one of the holder and the generating means, and abutments provided by the other.

The present invention is particularly suitable for use with tape cassettes of physiological or other medical diagnostically used signals, for example of ECG traces, for which it is important to erase a tape before re-use.

Apparatus according to the invention can be constructed in particularly simple technical form to render possible, through clearly defined end positions of rotation, a clearly defined movement of the tape cassette in the magnetic field of the magnetic field generator and in addition it can ensure a clearly defined rotational movement covering an angle of rotation of at least about 90".

Experience has shown that turning through such an angle is sufficient to effect a sufficiently reliable and complete erasure of a magnetic tape of a cassette.

For a better understanding of the present invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 is a plan view of one embodiment of an apparatus according to the invention Figure 2 is a front elevation of the apparatus of Figure 1 Figure 3 is an enlarged illustration of part of the apparatus of Figure 1 as seen in the direction of the arrow X, Figure 4 is a perspective view of a second embodiment of an apparatus according to the invention, and Figure 5 is a section along the line V-V through the apparatus of Figure 4.

In the embodiment illustrated in Figures 1 to 3, a knurled disc 11 is so mounted as to be rotatable about an axis 12 between two assembly plates 1 and 2. Each of the plates support four permanent magnets 3 to 6 and 7 to 10 respectively. Mounted on the knurled disc 11 and two guide bars 13 and 14, between which a tape cassette 15 with magnetic tape reels 16. indicated in chain lines, can be pushed in the direction of arrow 17 for erasure of information stored on the tape. When cassette 15 is introduced between the guide bars, a cassette ejector 18 is brought into a cocked position against the pressure of an ejector compression spring 19. The cassette 15 is formed with a locking slot 20 in its lower side face. A locking tongue 21 can snap into this locking slot 20 when the cassette is fully introduced. The locking tongue 21 is a component part of a lever 22 which is rotatably attached to the knurled disc 11 by means of a pivot pin 23.

The compression spring 24 at the other end of the lever pushes the locking tongue 21 into the locking slot 20 in the cassette 15, when the cassette is inserted. For releasing this locking means, a rolling lug 25 on the lever 22 co-operates with a pin 26 in a snap-action manner (detail shown on a larger scale in Figure 3). The pin 26, which is fixedly connected to assembly plate 2, always encounters the lug 25 of the lever 22 only when the knurled disc 11 has been turned at least once through 360" together with the cassette 15 when inserted. This complete revolution of cassette 15 in the magnetic field of the permanent magnets (4 times 90 ) substantially ensures that the recording tape of cassette 15 is adequately cleared. This special locking means also ensures that a complete revolution occurs.

so that there is no danger of the tape being incompletely cleared, or not at all, owing to the rotational movement taking place only incompletely, or not at all. Only at the end of each complete revolution does the lug 25 again roll over the pin 26 in the rotation of the knurled disc. In this way. the locking tongue 21 is pushed outwards and snaps out of the locking slot 20 in the cassette 15. The cassette 15 thus unlocked is then automatically ejected by the cassette ejector 19.

In the embodiment of Figures 4 and 5 a coil 27 is provided as the magnetic field generator. The coil 27 consists. for example.

of about 25()() turns of coil wire, the wire having a diameter of about 0.6 mm. The coil wire is wound on a hollow carrier body 28 having a gap 29, in which holder 30 for receiving a magnetic tape cassette (for example 15 in Figure 1) is so disposed as to be rotatable about an axis 31. Lever 32 is provided on the holder 30 for rotating the holder. This serves also to abut against the carrier body 28 in the () angular position and in the 9() angular position. For clearing the magnetic tape, therefore. the cassette is pushed in the direction of the arrow 33 through the coil aperture 29 into the holder 30, with the holder in the zero position. The cassette is then brought into the 9() angular position by rotation of the holder in the direction of the arrow 34 bv means of the turning lever 32. After being turned back into the zero position. the cassette is completely cleared and can thus be used for further recordings.

WHAT WE CLAIM IS: 1. Apparatus for erasing information recorded on tape of a tape cassette comprising: means for generating a magnetic field; and a holder for holding both reels of a magnetic tape cassette in said magnetic field; wherein one of said holder and said magnetic field is rotatable relative to the other from a first to a second position, through an angle of rotation of substantially 90 , about an axis extending substantially perpendicularly to the magnetic field lines generated in the region of a tape when in said holder, the apparatus being arranged in such a way that relative rotation of said one from the first to the second position substantially erases information recorded on tape on both reels of the tape cassette.

2. Apparatus according to claim 1 wherein said one of the holder and the magnetic field is rotatable relative to the other through an angle of substantially 360" about said axis.

3. Apparatus according to claim 1 wherein said one of the holder and the magnetic field is reversibly rotatable relative to the other back from the second to the first position.

4. Apparatus according to claims 1, 2 or 3 and having means for indicating to a user that relative rotation has occurred through a given angle which is at least 90".

5. Apparatus according to claim 4, when appended to claim 1 or 3, wherein said indicating means comprise a grip provided on one of said holder and said generating means and abutments provided by the other to define said first and second positions.

6. Apparatus according to claim 4, when appended to claim 1 or 2 wherein said given angle is substantially 360"C.

7. Apparatus according to any one of claims 1 to 6, wherein said holder comprises spaced guide surfaces for receiving a cassette there between.

8. Apparatus according to claim 7, wherein said holder comprises a rotatable member having a recess opposed side walls of which are said guide surfaces.

9. Apparatus according to any one of the preceding claims, comprising a rotatable part having a pivot pin.

10. Apparatus according to one of the preceding claims, comprising a rotatable disc having a knurled part for manual manipulation thereof.

11. Apparatus according to any one of the preceding claims wherein said generating means comprises a permanent magnet arrangement having a pole gap containing said holder.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. on the tape. When cassette 15 is introduced between the guide bars, a cassette ejector 18 is brought into a cocked position against the pressure of an ejector compression spring 19. The cassette 15 is formed with a locking slot 20 in its lower side face. A locking tongue 21 can snap into this locking slot 20 when the cassette is fully introduced. The locking tongue 21 is a component part of a lever 22 which is rotatably attached to the knurled disc 11 by means of a pivot pin 23. The compression spring 24 at the other end of the lever pushes the locking tongue 21 into the locking slot 20 in the cassette 15, when the cassette is inserted. For releasing this locking means, a rolling lug 25 on the lever 22 co-operates with a pin 26 in a snap-action manner (detail shown on a larger scale in Figure 3). The pin 26, which is fixedly connected to assembly plate 2, always encounters the lug 25 of the lever 22 only when the knurled disc 11 has been turned at least once through 360" together with the cassette 15 when inserted. This complete revolution of cassette 15 in the magnetic field of the permanent magnets (4 times 90 ) substantially ensures that the recording tape of cassette 15 is adequately cleared. This special locking means also ensures that a complete revolution occurs. so that there is no danger of the tape being incompletely cleared, or not at all, owing to the rotational movement taking place only incompletely, or not at all. Only at the end of each complete revolution does the lug 25 again roll over the pin 26 in the rotation of the knurled disc. In this way. the locking tongue 21 is pushed outwards and snaps out of the locking slot 20 in the cassette 15. The cassette 15 thus unlocked is then automatically ejected by the cassette ejector 19. In the embodiment of Figures 4 and 5 a coil 27 is provided as the magnetic field generator. The coil 27 consists. for example. of about 25()() turns of coil wire, the wire having a diameter of about 0.6 mm. The coil wire is wound on a hollow carrier body 28 having a gap 29, in which holder 30 for receiving a magnetic tape cassette (for example 15 in Figure 1) is so disposed as to be rotatable about an axis 31. Lever 32 is provided on the holder 30 for rotating the holder. This serves also to abut against the carrier body 28 in the () angular position and in the 9() angular position. For clearing the magnetic tape, therefore. the cassette is pushed in the direction of the arrow 33 through the coil aperture 29 into the holder 30, with the holder in the zero position. The cassette is then brought into the 9() angular position by rotation of the holder in the direction of the arrow 34 bv means of the turning lever 32. After being turned back into the zero position. the cassette is completely cleared and can thus be used for further recordings. WHAT WE CLAIM IS:

1. Apparatus for erasing information recorded on tape of a tape cassette comprising: means for generating a magnetic field; and a holder for holding both reels of a magnetic tape cassette in said magnetic field; wherein one of said holder and said magnetic field is rotatable relative to the other from a first to a second position, through an angle of rotation of substantially 90 , about an axis extending substantially perpendicularly to the magnetic field lines generated in the region of a tape when in said holder, the apparatus being arranged in such a way that relative rotation of said one from the first to the second position substantially erases information recorded on tape on both reels of the tape cassette.

12. Apparatus according to any one of

claims 1 to 10 wherein said generating means comprises a coil mounted on a hollow carrier within which the holder is disposed.

13. Apparatus according to any one of the preceding claims wherein there is provided means for locking the cassette in the holder during the relative rotation.

14. Apparatus according to claim 13 when appended to claim 6, wherein said locking means comprises a snap-action latching means attached to the holder for engaging a locking slot in a cassette until the holder has been rotated to the second position.

15. Apparatus according to claim 14 wherein said latching means engages said locking slot until the holder has been returned to said first position.

16. Apparatus according to claim 14 or 15 wherein there is further provided a lug for engaging a pin in a snap-action manner for releasing said snap-action latching means from said locking slot.

17. Apparatus according to claim 15 or 16 wherein said snap-action latching means comprises a lever having a locking tongue and being angularly displaceable relative to the holder, there being a spring for urging the locking tongue into said locking slot when a cassette is inserted into the holder.

18. Apparatus according to any one of the preceding claims wherein there is provided means for ejecting a cassette from the holder.

19. Apparatus according to claim 18 when appended to any one of claims 13 to 17 wherein said ejecting means is operable to eject the cassette only when said locking means is released.

20. Apparatus according to claim 18 or 19 wherein said ejecting means comprises a member for abutment with a cassette when inserted into the holder, which member is attached to the holder by means of a spring arranged to store the energy required for cassette ejection.

21. Apparatus substantially as hereinbefore described with reference to Figures 1, 2 and 3, or with reference to Figures 4 and 5 of the accompanying drawings.