GB1568841A

GB1568841A - Magnetic-tape cassette and a recording and/or playback apparatus for use with the cassette

Info

Publication number: GB1568841A
Application number: GB1126/77A
Authority: GB
Original assignee: Philips Electronic and Associated Industries Ltd
Current assignee: Philips Electronics UK Ltd
Priority date: 1976-01-15
Filing date: 1977-01-12
Publication date: 1980-06-04
Also published as: AU2128777A; ES461226A1; DE2700142B2; IT1076503B; ATA24976A; FR2338545A1; JPS5858748B2; DE2700142C3; BE850346A; CH613296A5; AT343928B; JPS52109919A; JPS58218086A; ZA767681B; NZ183058A; CA1072672A; NL7700505A; FR2338545B1; ES454999A1; JPH0310386U

Abstract

A cassette (4) with a magnetic tape (3) can be loaded into the apparatus. An erase head and a magnetic head (13) interact with the magnetic tape (3). A magnetising device (22) serves for the selective application of markings on a marking symbol carrier (19). The markings identify the relative position of the magnetic head (13) with respect to the magnetic tape (3). The magnetising device (22) has in a marking zone (25) of a marking symbol carrier (19) a marking element (23). The marking element (23) can be moved along the marking zone (25) synchronously with the relative movement between magnetic tape (3) and magnetic head (13). The magnetising device (22) serves for the selected magnetising of the marking element (23). With the marking element (23), the markings can be recorded on the marking symbol carrier (19) for storage and optical reading-out of the markings. The marking symbol carrier (19) is attached on the outside of a cassette wall (17). <IMAGE>

Description

(54) MAGNETIC-TAPE CASSETTE AND A RECORDING AND/OR PLAYBACK APPARATUS FOR USE WITH THE CASSETTE (71) We, PHILIPS ELECTRONIC AND ASSOCIATED INDUSTRIES LIMITED of Abacus House, 33 Gutter Lane, London, EC2V 8AH a British Company, 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 a cassette containing a magnetic recording tape carried on two winding hubs in the cassette, and to a magnetic recording and/or playback apparatus for use with the cassette, the apparatus comprising means for supporting the cassette, a scanning element for cooperation with the tape in the cassette, and means for driving the winding hubs to transport the tape from one hub to the other past the scanning element.

The invention relates particularly to a cassette which has a marking carrier secured to a wall thereof, and to a recording and/or playback apparatus having a marking element which, when the cassette is mounted on the apparatus and the apparatus is in operation, moves along a marking zone of the marking carrier on the cassette in synchronism with the relative movement between the tape and the scanning element and which is operable at will to produce a mark in said marking zone to give a visual indication on the marking carrier of the position of the scanning element relative to the ends of the tape.

United States Patent Specification 2,218,542 discloses an apparatus which is in particular intended for dictation purposes and in which the user of the apparatus can make optically identifiable marks in the form of punched-out slits in paper marking carriers with marking elements on the apparatus. Other apparatuses are known in which marks are made by other methods, such as by scribing marks on the marking carrier, by the removal of a layer of a special material from the marking carrier, and by burning-in a mark on a thermographic marking carrier, in which respect reference is made to, for example, United States Patent Specification 2,898,112 and the published German Patent Application 1,224,526. All these methods are to some extent intricate and expensive, demand a comparatively large amount of power for the application of the marks and produce marks on the marking carrier which cannot be erased or can be erased only with difficulty, so that a large number of interchangeable marking carriers must be supplied with such apparatus.

According to a first aspect of the present invention there is provided a cassette containing a magnetic recording tape carried on two winding hubs in the cassette, wherein to a wall of the cassette there is secured a marking carrier having a marking zone which is composed of magnetically orientatable particles which are visible when orientated in a given direction relative to said wall of the carrier.

It is to be noted that a recording medium with magnetically orientatable particles for the storage and optical read-out of information is known per se from United States Patent Specification 3,683,382. The concept underlying the present invention is the use of such medium as an optically readable marking carrier on a magnetictape cassette, and the provision of a recording and/or playback apparatus which is constructed for use with a cassette having such a marking carrier.

In a cassette according to the first aspect of the invention, the marking carrier may be detachably secured to the wall of the cassette. The marking carrier may be accommodated in a compartment in the wall of the cassette. Alternatively, it may be attached to the wall of the cassette by a clip which fits detachably on the cassette.

According to a second aspect of the invention there is provided a recording and/or playback apparatus for use with a magnetic-tape cassette according to the first aspect of the invention, comprising means for supporting the cassette, a scanning element for cooperation with the tape in the cassette, means for driving the winding hubs in the cassette to transport the tape from one hub to the other past the scanning element, a marking element which is made of a soft magnetic material and which, when the cassette is mounted on the apparatus and the apparatus is in operation, moves along the marking zone of the marking carrier on the cassette in synchronism with the relative movement between the magnetic tape and the scanning element, and a magnetizing device which is operable at will to magnetize the marking element so as locally to orientate the magnetically orientatable particles in the marking zone of the marking carrier so as to produce a mark in said marking zone to give a visual indication on the marking carrier of the position of the scanning element relative to the ends of the tape.

The magnetizing device may comprise a permanent magnet which is pivotally supported so as to be movable from a rest position towards the marking element.

In an embodiment of the apparatus which is constructed for use with a cassette in which the marking carrier has two of said marking zones composed of magnetically orientatable particles, two of said marking elements of soft magnetic material are provided on the apparatus for cooperation one with each marking zone of the marking carrier on the cassette, the permanent magnet being supported so as to be movable from its rest position towards either marking element selectively.

The magnetizing device may alternatively comprise an electrically energizable coil surrounding the marking element.

The apparatus may comprise a permanent magnetic and/or electromagnetic erase device for producing a magnetic field whereby particles in the marking zone of the marking carrier which are orientated in said given direction can be re-orientated for the purpose of erasing marks from the marking carrier.

Guide means may be provided for defining a path along which the cassette can be moved to pass the marking carrier through the magnetic field produced by the erase device.

The guide means may comprise a sleeve having a cross-section corresponding to that of the cassette and formed with entry and exit openings for the cassette.

Some embodiments of the cassette and apparatus according to the invention will be described in more detail with reference to the accompanying drawings, in which: Fig. 1 is a plan view of a-first embodiment of a cassette according to the invention mounted on a first embodiment of a recording and/or playback apparatus according to the invention, Fig. 2 is a sectional view taken on the line 11-11 of Fig. 1, Fig. 3 is a sectional side view of part of a second embodiment of a cassette according to the invention and part of a second embodiment of the apparatus for use with this embodiment of the cassette, Fig. 4 is a sectional side view of a third embodiment of a cassette according to the invention and part of a third embodiment of the apparatus for use with this embodiment of the cassette, and Fig. 5 is a plan view of a fourth embodiment of a cassette according to the invention.

The recording and/or playback apparatus shown in Figs. 1 and 2 is intended to be used in particular as a dictation apparatus and comprises a housing 1 with a recessed portion 2 in which a cassette 4 is placed which contains a magnetic tape 3. Drive spindles 5, 6 located in the apparatus cooperate with winding hubs 7, 8 in the cassette 4 in a conventional manner, so that the magnetic tape can be unwound from one winding hub and wound onto the other winding hub. The magnetic tape 3 then runs along a peripheral wall 9 of the cassette in which are formed openings 10, 11 through which scanning elements extend into the apparatus, in the present instance an erase head 12 and a recording playback head 13, to co-operate with the magnetic tape. The scanning element are mounted on a support 14, which is movable in the apparatus in the direction of the double arrow 15. Actuation means 16 which can be operated by a control element (not shown) engage with the support 14, so that the scanning elements can be withdrawn from the cassette into a rest position. In the situation shown in Fig. 1 and Fig.2 the scanning elements are in contact with the magnetic tape, and a quantity of the tape has already been transported from the hub 7 to the hub 8.

The apparatus is provided with a marking device for a marking carrier on which marks can be made at will to denote the relative position of the scanning elements with respect to the ends of the magnetic tape, so that, for example, if the apparatus is used for dictation purposes the beginning and the end of the dictation or the position of a correction can be identified. For this purpose a marking carrier 19, 20 is provided on each of the two major walls 17, 18 of the cassette 4, the carriers each having two marking zones 25 and 26 which are composed of magnetically orientatable particles, for the storage and optical readout of a mark. In such a carrier the magnetically orientatable particles, depending on whether they have been exposed to a magnetic field which extends in the plane of the carrier or perpendicular to this plane, may assume two different orientations, in one of which they reflect incident light and in the other of which they diffuse the incident light in the carrier material where it is then absorbed so that the carrier is bright in the first instance and is dark in the second instance. In the present example the marking carriers take the form of strips which are glued in position parallel to the longitudinal direction of the cassette in corresponding recesses formed in the walls 17, 18 of the cassette. Each of the two marking carriers then corresponds to a direction of transport of the magnetic tape from the one winding hub to the other, depending on whether the cassette has been inserted into the apparatus with the wall 17 or the wall 18 uppermost. The marking carrier which faces the outside of the apparatus and which is visible to the user is in the operative position. Since the marking carriers are secured to the cassette and as will be explained later herein, do not have to be replaced, they cannot be mislaid or inadvertently interchanged, for example during conveyance of the cassette from one place to another. The magnetically stored and optically readable marks can be erased magnetically because of the reversible orientation process of the particles in the marking zones of the marking carriers, so that even in the case of frequent use of a cassette the carriers are always re-usable after erasure, which will be described in more detail hereinafter.

For making marks on the marking carrier which is in the operative position a marking device 21 is provided, which comprises a magnetizing device 22 and two magnetizable marking elements 23, 24 which correspond to the two parallel marking zones 25 and 26 respectively on the marking carrier and which can be moved along these marking zones in synchronism with the relative movement between the magnetic tape 3 and the scanning elements 12, 13 which co-operated therewith. For this purpose, the marking device comprises a stationary spindle 27 along which a block 28 of a non-magnetizable material, in the present case a plastics material, is movable.

In this block the two marking elements 23 and 24, which are made of a soft-magnetic material, are embedded, the portions 29, 30 and 31, 32 respectively of the elements projecting from the block 28. The portions 30 and 32 are guided in slots 33 and 34 in a guide 35 on the housing 1 and at their free ends 36 and 37, which are pin-shaped, are bent downwards to terminate directly above and close to the marking carrier which is in the operative position, in this case the carrier 19. A semi-circular screw-threaded recess 38 formed in the block 28 cooperates with a screw-threaded spindle 39, which is rotatably journalled in bearings 40, 41 mounted on the support 14. By moving the support 14 from the operating position to the rest position to withdraw the scanning elements 12, 13 from the cassette, the threaded spindle 39 is disengaged from the recess 38 in the block 28. A spring 43 which is connected to the block 28 by a belt 42 then moves the block into a rest position which is defined by a stop 44 on the housing 1. In Fig. 1 this rest position is indicated by dotted lines 47. On the threaded spindle 39 is fixed a disk 48 which co-operates with a slipping clutch lining 49 fixed on a pulley 50 which is freely rotatable on the threaded spindle. From this pulley 50 a belt 51 runs to a part (not shown) of the apparatus which rotates during transport of the magnetic tape, for example a second pulley which is mounted on the winding spindle 6. In this way the block 28 and with it the marking elements 23 and 23 are moved axially along the spindle 27 in synchronism with the relative movement between the magnetic tape and the scanning elements, the free ends 36, 37 of the marking elements travelling over the corresponding marking zones 25 and 26 of the marking carrier 19.

With the aid of a scale 52 which is printed on the marking carriers it can also be seen how much magnetic tape is contained on the winding hubs 7 and 8 respectively.

The magnetizing device 22 comprises a rod-shaped axially magnetized permanent magnet 53 which is mounted on an arm 54 extending radially from a ring 55 which is rotatable around a hollow cylindrical projection 56 on the block 28, which projection concentrically surrounds the spindle 27. The ring 55 further comprises a second radially extending arm 57 having a bifurcated end 58 which embraces a bar 59 which extends parallel with the spindle 27 and which is supported at its ends by two arms 60 and 61 which are pivotable about the spindle 27. A knob 62 is connected to the arm 61. By means of the knob 62 the bar 59, and with it the arm 57, ring 55 and arm 54, can be rotated in any position of the block 28 along the spindle 27 to bring the permanent magnet 53 into engagement either with the portion 29 of the marking element 23 or with the portion 31 of the marking element 24. A spring-loaded locating means 63 which co-operates with the bar 59, as is shown in Figs. 1 and 2, defines a rest position of the actuation device for the permanent magnet, in which position this magnet is spaced from the portions 29 and 31 of the two marking elements When the apparatus is put into operation the support 14 is in its rest position, in which position the scanning element 12, 13 mounted on the support are withdrawn from the recess 2 in the housing 1. The block 28 with the marking elements 23 and 24 is then also in the rest position, in which it engages the stop 44. In this rest position of the block 28 the two marking elements 23 and 24, as shown by the dotted lines 47 in Fig. 1, are disposed to one side of the recess 2 so that they do not impede the insertion of a cassette 4 into the recess. Subsequently, the support 14 is moved into the operating position to insert the scanning elements 12, 13 into the cassette for engagement with the magnetic tape. This movement of the support 14 also brings the threaded spindle 39 into engagement with the threaded recess 38 in the block 28 after an inclined surface 45 formed on a member 46 projecting from the support 14 has displaced the block 28 in the direction of the arrow 64 to bring the marking elements 23, 24 to a starting position above the marking carrier 19, as shown by the dotted lines 65 in Fig. 1. When the drive means for the transport of the magnetic tape from the hub 7 to the hub 8 is now switched on, steps having been taken to ensure that, if necessary, the whole of the tape is wound on the winding hub 7, the block 28, driven by the threaded spindle 39, synchronously follows the movement of the magnetic tape so that the free ends 36, 37 of the marking elements 23, 24 are moved over the marking zones 25, 26 on the marking carrier 19.

If a specific point on the magnetic tape in respect of its position relative to the scanning elements is to be identified by means of a mark in the marking zone 25 or 26, the knob 62 is rotated on the spindle 27 so that the permanent magnet 53 is moved into contact with the portion 29 of the marking element 23 or the portion 31 of the marking element 24. As a result, the relevant marking element is magnetized so that the magnetic field which emanates from the free end 36 or 37 respectively of the marking element passes through the marking carrier 19 substantially at right angles to the plane of the carrier. The magnetically orientatable particles of the relevant marking zone on this carrier in the area directly beneath the face end of the magnetized marking element are influenced by the magnetic field in such a way that their orientation is altered at this point so that an optically visible mark is obtained and recorded on the marking carrier. Thus, such a mark can be made without mechanically loading any component, either the marking elements or the marking carrier, by simply moving a permanent magnet.

As the magnetic orientation of the particles of the marking zones of the marking carrier is reversible, such marks can also be magnetically erased. This is effected by means of a magnetic field which extends substantially in the plane of the marking carrier and which acts on the particles in the marking zone in a manner similar to that described in the aforesaid United States Specification No. 3,683,382.

In the simplest case marks can be erased with an axially magnetized rod magnet, which is manually passed over the relevant marking zone of the marking carrier with the longitudinal axis of the magnet extending parallel to the plane of the carrier. Thus, such a marking carrier is reusable, which is an important advantage, because it means that it is no longer necessary to have a large number of interchangeable marking carriers available.

In the second embodiment of Fig. 3 the marking carriers 19, 20 with marking zones of magnetically orientatable particles, are each inserted in a compartment 66, 67 formed in the walls 17 and 18 of the cassette 4. In the present case the two compartments each have an opening 68 and 69 respectively through which the respective marking carrier is visible. If the cassette is made of a 'transparent material, such openings may be dispensed with.

The marking device 21 again comprises a block 28 which is movable along a stationary spindle 27 and which has a screwthreaded recess 38 for cooperation with a screw-threaded spindle 39 which is driven in synchronism with the transport of the magnetic tape. A pivotable U-shaped lever 71, whose cross-piece 70 is parallel to the spindle 27 and is slidable in a slot 73 in the block 28, is loaded by a spring 72 in such a way as to urge the block 28 in a direction to hold the threaded recess 38 in engagement with the threaded spindle 39. A marking element 74 of a soft magnetic material is mounted in the block 28, the element having a portion which projects over the upper wall 17 of the cassette 4 and whose free end 75 is bent downwards to extend through the opening 68 in the wall 17 and terminate close to the marking carrier 19. By means of a push-button 76, which acts on the lever 71 via a rod 77, the lever 71 is pivotable against the action of the spring 72 to rotate the block 28 about the spindle 27 and thereby move the marking element 74 away from the cassette, as is indicated by the dotted lines 78 in Fig. 3, so that the marking element 74 does not impede the insertion or removal of a cassette into or from the apparatus.

The magnetizing device 22 for the marking element 74 is constituted bv a coil 79 which surrounds the element and which via two sliding contacts 80, 81 makes electrical contact with two contact tracks 82, 83 provided in the apparatus. The two contact tracks are connected to an energizing circuit 84, which includes a switch 85 which can be closed by depression of a push-button 86. When the switch 85 is closed current will flow through the coil 79, regardless of the position of the block 28 along the spindle 27, so that a magnetic field is produced by the coil. This magnetic field passes via the marking element 74 to the marking carrier 19 and through the plane of this carrier substantially at right angles thereto to produce at the location of the marking element a re-orientation of the magnetically orientatable particles in the marking zone of the carrier, so that again an optically visible mark is obtained and recorded on the carrier.

The apparatus of Fig. 3 is provided with an erase device 87 for the marking carrier.

This device comprises an axially magnetized rod magnet 89 whose longitudinal axis is substantially parallel to the upper wall of the housing 1 of the apparatus and which is fitted in a recess 88 formed in this wall of the housing 1. The rod may be embedded in a plastics material 90. The magnet produces a magnetic field 91 which extends outside the apparatus and which may be used as an erase field for the marking carriers on the cassette. For erasure, a cassette, with the marking carriers, is passed through the erase field by hand in such a way that this field passes through the plane of the marking carriers. For defining the paths to be followed by the marking carriers during their passage through the field, a guide track for the cassette is provided on the housing 1 above the permanent magnet 89, which guide track consists of a channel member 92 which conforms to the cross-section of the cassette and along which a cassette can be moved by hand in the direction of the arrow 93. Thus, the position of the marking carriers 19 and 20 relative to the erase field 91 is accurately defined, so that perfect erasure is guaranteed. Means may also be provided for moving the cassette automatically along such a guide track.

In the embodiment of Fig. 4 a marking carrier 19 having two marking zones composed of magnetically orientatable particles is mounted on a peripheral wall 94 of the cassette 4, preferably on that wall which is opposite the peripheral wall 9 through which the scanning elements 12 and 13 enter the cassette for cooperation with magnetic tape. In this embodiment the cassette 4 is supported in a tunnel-shaped cassette holder 95 which is pivoted to the housing 1 and which has a wall 96 which extends parallel to the marking carrier 19 and which has an opening 97 for the passage of the two free ends of the two marking elements 23, 24. The two marking elements act on the same marking zone of the marking carrier, so that when the cassette is turned over, they both act on the other marking zone. In order to make the marking carrier visible to the user of the apparatus, the housing 1 has an opening 98 below which a mirror 99 is suitably arranged. If desired, an illuminating device may be provided.

In this apparatus the erasing device 87 comprises a flat coil 100 which can be energized electrically so as to produce a magnetic alternating field through which a cassette can be passed together with the marking carrier. For this purpose a guide track for the cassette is provided which in this case takes the form of a sleeve 101 which has a cross-section corresponding to that of the cassette. The sleeve has an entrance opening 102 and an exit opening 103 and extends vertically through the flat coil 100, which is disposed in a horizontal plane. For erasing a mark the cassette is inserted in the direction of the arrow 104 into the entrance opening 102 and is allowed to fall through the sleeve 101 to the bottom 105 thereof, whence it can be removed by hand through the exit 103. The marking carrier is thus passed through the erase field in such a way that the erase field extends substantially in the plane of the carrier, so that the marks recorded on the marking carrier are erased.

In the cassette shown in Fig. 5 a marking carrier is secured to each of the two major walls of the cassette by a channel-shaped clip 106 of transparent material which extends over part of each of the two walls.

In Fig. 5 the wall 17 and the marking carrier 19 are visible. For fitting the clip onto the cassette a snap connection is provided which consists of a projection 108 which is formed on the bottom 107 of the channelshaped clip and which engages in a recess 109 which is formed in a peripheral wall 94 of the cassette. This enables the marking carrier to be replaced in a simple way, the side walls of the clip also forming a protection for the marking carriers. Such a cassette can be passed with the marking carriers through an erase device. It is alternatively possible to pass only the marking carriers through an erase device. It is also possible to have an arrangement whereby, while the cassette is still located in the operative position on the recording and/or playback apparatus, the marks of the marking carriers can be erased with the aid of an erase device which is movably disposed on the apparatus.

The marking carrier may have a shape other than that of a strip; for example, it may have a circular shape with concentric marking zones.

WHAT WE CLAIM IS: 1. A cassette containing a magnetic recording tape carried on two winding hubs in the cassette, wherein to a wall of the cassette there is secured a marking carrier having a marking zone which is composed of magnetcially orientatable particles which are visible when orientated in a given direction relative to said wall of the carrier.

2. A cassette as claimed in Claim 1, wherein the marking carrier is detachably secured to the wall of the cassette.

3. A cassette as claimed in Claim 2, wherein the marking carrier is accommodated in a compartment in the wall of the cassette.

4. A cassette as claimed in Claim 2, wherein the marking carrier is attached to the wall of the cassette by a clip which fits detachably on the cassette.

5. A recording and/or playback apparatus for use with a magnetic-tape cassette as claimed in any of Claims to to 4, comprising means for supporting the cassette, a scanning element for cooperation with the tape in the cassette, means for driving the winding hubs in the cassette to transport the tape from one hub to the other past the scanning element, a marking element which is made of a soft magnetic material and which, when the cassette is mounted on the apparatus and the apparatus is in operation, moves along the marking zone of the marking carrier on the cassette in synchronism with the relative movement between the magnetic tape and the scanning element, and a magnetizing device which is operable at will to magnetize the marking element so as locally to orientate the magnetically orientatable particles in the marking zone of the marking carrier so as to produce a mark in said marking zone to give a visual indication on the marking carrier of the position of the scanning element relative to the ends of the tape.

6. An apparatus as claimed in Claim 5, wherein the magnetizing device comprises a permanent magnet which is pivotally supported so as to be movable from a rest position towards the marking element.

7. An apparatus as claimed in Claim 6 for use with a cassette as claimed in any of Claims 1 to 4 and in which the marking carrier on the cassette has two of said marking zones composed of magnetically orientatable particles, wherein two of said marking elements of soft magnetic material are provided on the apparatus for cooperation one with each marking zone of the marking carrier on the cassette, the permanent magnet being supported so as to be movable from its rest position towards either marking element selectively.

8. An apparatus as claimed in Claim 5, wherein the magnetizing device comprises an electrically energizable coil surrounding the marking element.

9. An apparatus as claimed in any of Claims 5 to 8, comprising a permanent magnetic and/or electromagnetic erase device for producing a magnetic field whereby particles in the marking zone of the marking carrier which are orientated in said given direction can be re-orientated for the purpose of erasing marks from the marking carrier.

10. An apparatus as claimed in Claim 9, wherein guide means are provided for defining a path along which the cassette can be moved to pass the marking carrier through the magnetic field produced by the erase device.

11. An apparatus as claimed in Claim 10, wherein said guide means comprise a sleeve having a cross-section corresponding to that of the cassette and formed with entry and exit openings for the cassette.

12. A recording and/or playback apparatus substantially as herein described with reference to Figs. 1 and 2 or Fig. 3 or Fig. 4 of the accompanying drawings.

13. A magnetic-tape cassette substantially as herein described with reference to Figs. 1 and 2 or Figs. 3, 4 or 5 of the accompanying drawings.

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. of an erase device which is movably disposed on the apparatus. The marking carrier may have a shape other than that of a strip; for example, it may have a circular shape with concentric marking zones. WHAT WE CLAIM IS:

1. A cassette containing a magnetic recording tape carried on two winding hubs in the cassette, wherein to a wall of the cassette there is secured a marking carrier having a marking zone which is composed of magnetcially orientatable particles which are visible when orientated in a given direction relative to said wall of the carrier.