Cassette type magnetic recording/reproducing apparatus

Abstract: A cassette type magnetic recording/reproducing apparatus, such as a tape recorder, can accommodate a magnetic tape cassette (201) at a tape cassette attachment position within the main body of the apparatus so that the tape can be extracted by a loading mechanism so as to be loaded onto a predetermined tape running passage in the apparatus. The loading operation of the magnetic tape by the loading mechanism is enabled only when it is sensed by a switch (64) that a cassette holder (3) for attaching the tape cassette at the tape cassette attachment position is locked at the tape cassette attachment position and by switches (128) that the tape cassette is attached at the tape cassette attachment position. Thus a positive tape loading operation is ensured and the magnetic tape as well as various operating units within the main body of the apparatus are protected from damage.

Description: The invention relates to cassette type magnetic recording/reproducing apparatus. In apparatus of this kind, such as a tape recorder, magnetic tape accommodated within a tape cassette attached at a tape cassette attachment position within the main body of the recording/reproducing apparatus can be extracted by a loading mechanism or unit and loaded onto a predetermined tape running route or path. In previously proposed rotary magnetic head type audio PCM tape recorders or video tape recorders, a tape cassette acommodating a magnetic tape is employed as the recording medium and the magnetic tape accommodated within the tape cassette is caused to run as it is wrapped around a tape guide drum of a rotational magnetic head device, and is slidably contacted by a rotating magnetic head for recording/reproducing audio or video signals. Usually there is a cassette holder and a tape cassette transfer member supported for movement between a tape cassette inserting and detachment position and a tape cassette attachment position, and the tape cassette is attached at the tape cassette attachment position by way of the tape cassette transfer member or the cassette holder. In apparatus employing a rotating magnetic head device, the magnetic tape taken out from the tape cassette is wrapped around a tape guide drum of the rotating magnetic head device at a predetermined angle for slidingly contacting the rotating magnetic head. For this reason, the tape running route or path is intricate in profile and in the form of a letter M or a letter U with the magnetic head device at the centre. Since the magnetic tape is loaded along an intricate tape route, a loading mechanism including a shifting guide roller is provided in the cassette type magnetic recording/reproducing apparatus. The magnetic tape is taken out of the tape cassette by way of the aforementioned loading mechanism so as to be wrapped around the tape guide drum and automatically loaded onto the tape travel path. Therefore, in a cassette type magnetic recording/reproducing apparatus in which the magnetic tape is automatically loaded onto the tape travel path through the loading mechanism, it is necessary that the tape cassette be attached positively and accurately at the tape cassette attachment position. The loading mechanism is so contructed and designed that the magnetic tape extending on the front side of the tape cassette can be hooked for extraction by tape guide means, such as shifting guider rollers. Therefore, when the tape cassette is not attached accurately at the predetermined tape cassette attachment position, it may occur that the tape guide means are not engaged with the magnetic tape or are disengaged therefrom during extraction so that it may become impossible to perform a tape loading operation. Also, when the tape guide means are not engaged accurately with the magnetic tape, the magnetic tape may not be reliably protected from possible damage, while the loading mechanism itself may be destroyed. In previously proposed cassette type magnetic recording/reproducing apparatus, the operation of the loading mechanism is started as soon as it is sensed that the cassette holder has been shifted to the tape cassette attachment position to effect loading of the magnetic tape, or alternatively, a loading start switch may be actuated after the cassette holder has been shifted to the tape cassette attachment position to start loading of the magnetic tape. Thus, in the conventional cassette type magnetic recording/reproducing apparatus, the loading operation is started without checking that the cassette holder has been correctly shifted to the tape cassette attachment position and that the tape cassette has been correctly attached at the tape cassette attachment position. Thus there is a risk that the loading mechanism can be actuated when the cassette holder has been shifted to the tape cassette attachment position, even though the tape cassette is not attached correctly at the tape cassette attachment position. Therefore it may occur that the magnetic tape loading may cause damage to the magnetic tape and to operating units including the tape loading mechanism. In addition, in the above described cassette type magnetic recording/reproducing apparatus employing a rotating magnetic head device, the magnetic tape is extracted out of the tape cassette and wrapped around the rotating magnetic head device spaced apart from the tape cassette along the tape travel path or route. If a tape cassette ejecting operation is effected during the loading operation in which the magnetic tape is extracted or pulled out onto the tape route or the unloading operation in which the magnetic tape is pulled back into the tape cassette or under the loading condition in which the magnetic tape is wrapped around the rotating magnetic head device, the tape cassette ejecting operation may be performed while the magnetic tape is still extended on the tape route without being accommodated within the tape cassette. The magnetic tape will be pulled out in such case as it is entwined about tape guide means such as tape guide rollers so that the tape may be broken or otherwise damaged. In addition to the magnetic tape being damaged, mechanical units including the tape running mechanism or the loading mechanism may be damaged by the magnetic tape remaining on the tape route. Patent Specification US-A-4 639 797 discloses recording or reproducing apparatus wherein a cassette and a drum are relatively movable into and out of operating relationship with one another and wherein switches are provided to detect that a cassette has been lowered and is loaded and further switches detect movement of a cassette loading stand close to the drum and movement of the cassette loading stand away from the drum. According to the invention, there is provided a cassette type magnetic recording/reproducing apparatus, comprising: a cassette holder supported for movement between a tape cassette inserting and detachment position and a tape cassette attachment position; locking means to lock the cassette holder in the tape cassette attachment position; tape loading means to pull a magnetic tape accommodated within a tape cassette held at the tape cassette attachment position out of the tape cassette to load it onto a predetermined tape running path; and tape cassette attachment sensor means to sense when a tape cassette accommodated and held in the cassette holder is attached at the tape cassette attachment position; characterised by cassette holder lock sensor means to sense when the cassette holder is locked in the tape cassette attachment position; and means to actuate the tape loading means only when the locking of the cassette holder is sensed by the cassette holder lock sensor means simultaneously with the sensing of tape cassette attachment by the tape cassette attachment sensor means. Thus loading of the magnetic tape accommodated inside the tape cassette onto a predetermined tape running route is enabled only when the cassette holder lock is sensed by the cassette holder lock sensor means and tape cassette attachment is simultaneously sensed by the tape cassette attachment sensor means. Thus it is sensed by the cassette holder loading sensor whether or not the cassette holder accommodating and holding the tape cassette has been locked at the tape cassette attachment position, while it is also sensed by the tape cassette attachment sensor whether or not the tape cassette held in the cassette holder has been attached at the tape cassette attachment position. The operation of the loading mechanism is started when the cassette holder lock is sensed by the cassette holder lock sensor and also the tape cassette attachment is simultaneously sensed by the tape cassette attachment sensor to enable the loading of the magnetic tape. An outer lid may be provided so as to be operable and closeable independently of the cassette holder and when closed to cover at least the cassette holder in the tape cassette attachment position; outer lid sensor means can be provided to sense a closed statement of the outer lid; and loading starting means can start loading of the magnetic tape by the tape loading means operable when the outer lid sensor means senses the closure of the outer lid. The invention is diagrammatically illustrated by way of example in the accompanying drawings, in which:- Figure 1 is an exploded perspective view showing portions of a cassette type magnetic recording/reproducing apparatus according to the invention in the form of a rotating magnetic head digital audio tape recorder; Figure 2 is a perspective view of the tape recorder of Figure 1; Figure 3 is a plan view showing a state of loading mechanism of the recorder of Figure 1 prior to actuation thereof; Figure 4 is a plan view showing a state of the loading mechanism after actuation thereof; Figure 5 is a perspective view showing a relation between a cassette holder and a cassette holder locking level of the recorder; Figure 6 is a right-hand side view of the recorder of Figure 1 showing a state of rotation of the cassette holder in a tape cassette inserting and detachment position; Figure 7 is a right-hand side view of the recorder of Figure 1 showing a state of rotation of the cassette holder in the tape cassette attachment position. Figure 8 is a perspective view showing a non-actuated state of an ejection mechanism of the recorder of Figure 1; Figure 9 is a perspective view showing an operating state of the ejection mechanism; Figure 10 is a left-hand side view of the recorder of Figure 1 showing an opened state of an outer lid; Figure 11 is a left-hand view showing a closed state of the outer lid; Figure 12A is a diagrammatic plan view showing an opening and closing mechanism for the outer lid; Figure 12B is a front view of the opening and closing mechanism for the outer lid; Figure 12C is a side view showing the lid-opening operation of the opening and closing mechanism of the outer lid; Figure 13 is a perspective view from below showing an unlocking portion of a cassette holder locking mechanism of the recorder of Figure 1. Figure 14 is a diagrammatic side view showing an operating state of a cassette holder locking sensor switch of the recorder sensor switch of Figure 1; Figure 15 is a time chart showing operating states of the cassette holder locking sensor switch and a tape cassette attachment sensor switch of the recorder of Figure 1; Figure 16 is a perspective view from above of a tape cassette employed in the recorder of Figure 1; Figure 17 is a perspective view from below of the tape cassette. Figure 18 is a perspective view showing an opening and closing state of a front lid of the recorder of Figure 1; and Figure 19 is a bottom view showing a shifting state of a closure plate of the recorder of Figure 1. Before describing the embodiment of the rotating magnetic head type digital audio tape recorder shown in the drawings a tape cassette employed in the tape will be described. Referring to Figures 16 to 19, a tape cassette 201 is formed of a cassette body 204 consisting of an upper half 202 and a lower half 203 abutted and connected to each other. A pair of tape reels 205 and 206 are rotatably supported within the cassette body 204 and a magnetic tape 207 is wrapped around the tape reels 205 and 206. The tape 207 extends outwardly of the front side of the cassette body 204 through tape extraction openings 208 and 209 formed on both forward surface sides of the cassette body 204, and is wound from the one tape reel 205 to the other tape reel 206. On the front side of the cassette body 204, a front cover 210 is rotatably mounted to protect the magnetic tape 207 extended on the front side of the cassette body 204 when the tape cassette 201 is not engaged with the tape recorder. As shown in Figure 18, the front cover 210 is biased to be turned in a direction of closing in which it covers the magnetic tape 207 extended on the front side of the cassette body 204 by a torsion coil spring 211 acting as biasing means wound about a rotary shaft 210a. As shown in Figures 17, 18 and 19, a closure plate 214 having a substantially U-shaped cross-section is mounted on the bottom side of the cassette body 204 to slide in a back and forth direction for closing through-holes 212 and 213 formed in the bottom side of the cassette body 204 to accommodate reel shafts while the tape cassette is not engaged with the tape recorder for preventing intrusion of dust and dirt into the cassette body 204 to protect the magnetic tape 207. A pair of lugs 215, 215 are formed on the forward edge of the closure plate 214. When the plate is urged by a torsion spring 216 mounted on the cassette body 204 so as to be shifted towards the front side of the cassette body 204 in a direction to close the through-holes 212, 213 for the reel shafts, as shown in Figure 19, the lugs 215, 215 are engaged with the front side of the cassette half 204, as shown in Figure 17, to regulate the shifting position of the closure plate 214. On the lower edge of the front cover 210 registering with the lugs 215, 215, there are formed recesses 217, 217 acting as clearances when the cassette body 204 is shifted in relation to the closure plate 214. A pair of through-holes 218, 218 are formed in the main surface of the closure plate 214 and, when the closure plate 214 is relatively shifted towards the rear of the cassette half 204, the through-holes 218, 218 are in register with the through-holdes 212, 213 formed in the bottom plate of the lower half 203, such that reel drive shafts, not shown, provided in the tape recorder can intrude into the cassette body 204. As the closure plate 214 is moved forward so that, as shown in Figure 18, the plate 214 closes the lower portion of a space 219 confronted by tape extraction means of a loading unit, which is provided in the tape recorder for extracting the tape 207 lying on the front side of the cassette body 204 from the cassette body 204, the through-holes 218, 218 in the closure plate 214 and the through-holes 212, 213 in the lower half 204 are shifted relative to each other and the through-holes 212, 213 are closed by the main surface of the closure plate 214. The plate 214 is formed with shallow grooves 220 into which intrude a pair of ribs formed with the bottom plate of the cassette holder as later described and acting as means for disengaging the engaging means to the closure plate 214. These shallow grooves are formed to extend in the fore and aft direction of the closure plate 214 and are open at the forward edge of the plate 214. Each of the shallow grooves 220 is formed with an engaging opening 223 and an engaging recess 224 into which is engaged each of engaging projections 222 of locking members 221 provided on the cassette body 204 for retaining the closure plate 214 in a closure position in which the closure plate 214 closes the space 219 and the through-holes 212 and 213 and an open position in which the space 219 and the through-holes 212 and 213 are opened. In forming the locking member 221, the bottom plate of the lower half 203 is cut through in the form of a letter U so that the rear end of each of the locking members 221 connects to the bottom plate of the lower half 203 and a hemi-spherical engaging projection is formed on the lower surface of the forward end section of each of the locking members 221. As shown in Figures 17 and 19, when the closure plate 214 is closed, the projections 222 of the locking members 221 are engaged in the engaging openings 223 formed in the closure plate 214 to retain the closure plate 214 against shifting towards the open position. Within the cassette body 204, a reel lock lever 226 is provided to extend widthwise on the inner surface of the upper half 202. The lever 226 serves the purpose of preventing the tape reels 205 and 206 rotatably mounted within the cassette body 204 from being turned inadvertently and thereby loosened and/or damaged during non-attachment to the tape recorder. The lever 226 is slidably supported in the fore and aft direction with respect to the tape reels 205 and 206 by a pair of slide guide pins 227, 227 formed on the inner surface of the upper half 202 and engaging in a pair of elongate openings 228, 228 formed in the lever 226. The lever 226 is biased to be shifted towards the tape reels 205 and 206 by a torsion coil spring 229 mounted on the inner side of the upper half 202. The reel lock lever 226 is formed on its one side with thrust members 230, 230 abutting on the upper peripheral surfaces of the tape reels 205 and 206 to restrain the tape reels 205 and 206 against rotation. On both sides of the reel lock lever 226 are formed shifting arms 231, 231 extending in the fore and aft direction along the lateral sides of the cassette body 204. The shift arms 231, 231 engage with rotary members 210 b , 210 b of the front cover 210 when the front cover 21 is opened. When the front cover 210 is turned for opening the front side of the cassette body 204 as shown in Figure 18, the shifting arms 231 are shifted by the rotary members 210 b of the lid 210 towards the front of the cassette body 204, such that the reel lock lever 226 is shifted in a direction away from the tape reels 205 and 206 against the urging force of the torsion coil spring 229. By such shifting of the reel lock lever 226 the tape reels 205, 206 are released from the pressure of the thrust members 230, 230 and are free to rotate to permit the magnetic tape 207 to be reeled out of the cassette body 204. The above described rotary tape cassette 201 can be mounted in a magnetic head type digital audio tape recorder the general structure of which is shown in Figure 1 to 4. The recorder comprises a cassette holder 3 supported by a mechanical chassis 2 disposed in an outer casing 1 making up a main body of the tape recorder. The cassette holder 3 is mounted for rotation between a tape cassette insertion and take-out position outside of the outer casing 1 and a tape cassette attachment position on the chassis 2. An outer lid 4 is mounted for rotation on the outer casing 1 and can close and cover the cassette holder 3 when the cassette holder 3 is turned to the tape cassette attachment position. The tape cassette 201 is attached at the tape cassette attachment position as the cassette holder 3 holding the tape cassette 201 therein is turned from the cassette inserting and take-out position to the tape cassette attachment position on the chassis 2. At this tape cassette attachment position, there are provided a pair of reel blocks 7 and 8 provided respectively with reel shafts 5 and 6 engaged respectively with the tape reels 205 and 206 of the tape cassette 201 and able to take up the magnetic tape 207 on one of the tape reels 205 and 206 upon rotational operation of these reels 205 and 206. The reel blocks 7 and 8 are driven for rotation by a reel motor, not shown. At the tape cassette attachment position, a height position setting pin 9 is mounted upright for setting the height position of the attached tape cassette 201. On the side opposite to the side where the reel blocks are provided for attachment of the cassette 201, there is provided, as shown in Figures 3 and 4, a rotary magnetic head device 10 in which is accommodated the magnetic tape 207 reeled out from the tape cassette 201 by way of the mechanical chassis 2. Between the tape cassette attachment position and the rotary magnetic head device 10, there are provided a pair of shift guides 11 and 12 constituting a loading mechanism by which the magnetic tape 207 is taken out from the tape cassette 201 and wrapped about a tape guide drum of the rotary magnetic head device 10. A tape guide roll 13 and an inclined guide pin 14 are mounted in a manner such that the magnetic tape 207 is engaged therewith and thereby guided so as to be wrapped around the tape guide drum of the magnetic head device 10 at a predetermined angle, such as approximately 90°. The shifting guides 11 and 12 are guided by slide guide grooves 15 and 16 formed on the mechanical chassis 2 so as to be shifted between a position shown in Figure 3 whereat the tape guide roll 13 and the inclined guide pin 14 confront the space 219 of the tape cassette 201 attached to the tape cassette attachment position and a position shown in Figure 4 laterally of the magnetic head device 10. The shift guides 11 and 12 are shifted by rotationally driving loading rings 17 and 18 provided on the outer perimeter of the rotary magnetic head device 10. Thus the shifting guides 11 and 12 are connected by connecting arms 19 and 20 to the loading rings 17 and 18 and are shifted by these loading rings 17 and 18 which are rotationally driven by the loading motor 21. The loading rings 17 and 18 are connected to the loading motor 21 so that the driving power is transmitted from the motor to the loading rings by way of a connecting gearing 22 and a connecting belt 23. Between the tape cassette attachment position and the rotary magnetic head device 10, there are rotatably mounted a pinch roll supporting arm 26 carrying an end pinch roll 25 pressured onto a capstan shaft 24 to effect constant speed running of the magnetic tape 207, a tape guide supporting arm 28 carrying an end guide pin 27 and a tension regulating arm 30 carrying an end tension regulating guide pin 29. The pinch roll supporting arm 26, the tape guide supporting arm 28 and the tension regulating arm 30 are actuated by the rotational operation of the loading rings 17 and 18 to shifting the shifting the shifting guides 11 and 12 so as to be turned between a position towards the tape cassette attachment position shown in Figure 3 and a position towards the rotary magnetic head device 10 shown in Figure 4, and are turned with the shifting of the shifting guides 11 and 12 to load the magnetic tape 207 within the tape cassette 201 onto a predetermined tape path along which the tape may travel as it is wrapped around the rotary magnetic head device 10. Referring also to Figures 5, 6 and 7 the cassette holder 3 to attach the tape cassette 201 at the tape cassette attachment position on the mechanical chassis 2 comprises a holder framework 31 having a pair of rotary arms 32 and 33 extending towards the proximal end from both sides of a holder onto which the tape cassette 201 is loaded. The proximal ends of these rotary arms 32 and 33 are formed with through-holes 37, 37 into which are introduced supporting shafts 36 and 36 projecting perpendicular to confronting inner sides of a pair of chassis frames 34 and 35 attached to the chassis 2, so that the arms 32 and 33 may be turned between the tape cassette inserting and take-out position shown in Figure 6 and the tape cassette attachment position shown in Figure 7. The cassette holder 3 is biased to be turned towards the cassette inserting and take-out position by torsion coil springs 38, 38 wound about the supporting shafts 36, such that the cassette holder 3 is biased to be turned to the cassette inserting and take-out position under the force of the torsion coil springs 38, 38 unless the cassette holder is locked by cassette holder locking means as later described. The torsion coil springs 38, 38 wound about the supporting shafts 36, 36 are installed with the ends of first arms 38 a thereof retained in retaining apertures 39 formed in the rotary arms 32 and 33 of the cassette holder 3 and with the ends of second arms 38 b retained in retaining apertures 40 formed in the chassis frames 34 and 35, such that the cassette holder 3 is biased to be turned towards the cassette inserting and detaching position. Several of the retaining apertures 40 are formed radially in the chassis frame 34 and 35, as shown in Figures 6 and 7, so as selectively to be engaged by the second arms 38 b , so that the second arms 38 b may be engaged at variable engaging positions for adjusting the rotational urging force of the torsion coil springs 38 and 38 acting on the cassette holder 3. A cassette holder rotation regulating plate 41 is mounted across the pair of chassis frames 34 and 35 to support the cassette holder 3. The rotational urging position of the cassette holder 3 by the torsion coil springs 38 and 38 is regulated by having the mid portions of the rotary arms 32 and 33 abutted on the plate 41 and determining the tape cassette inserting and detaching position. The holder framework 31 onto which the tape cassette 201 is introduced and held is box-shaped and comprises a bottom plate 42 on which the tape cassette 201 rests, side plates 43 and 44 formed upright on both sides of the bottom plate 42 and an upper plate 45 facing the bottom plate 42 and extending across the side plates 43 and 44, as shown in Figures 1 and 5. The bottom plate 42 is formed with through-holes 46, 46 into which the reel shafts 5 and 6 transversely spaced apart from each other are introduced. A recess 47 having an inverted trapezoidal form is provided at the middle of the rear edge of the bottom plate 42. At the sides of the recess 47 and projecting slightly towards the rear are upstanding slide control projections 48, 48 to abut the lugs 215, 215 provided on the closure plate 214 for controlling the shifting of the closure plate 214 of the tape cassette 201. A pair of ribs 49, 49 to thrust the locking members 221 retaining the closure plate 214 of the tape cassette 201 are formed on the bottom plate 42 so as to protrude towards the side plates 43 and 44. The upper plate 45 is provided with a pair of cassette thrusting spring plates 50, 50 to thrust and support the tape cassette 201 introduced into and held in the holder framework 31 in position for preventing accidental removal of the tape cassette 201. The cassette thrusting spring plates 50, 50 are attached to the upper plate 45 at one end so that pressure rolls 51, 51 mounted on the ends of the plates confront the inside of the holder framework 31 via through-holes 52, 52 formed in the upper plate 45. It is noted that the cassette thrusting spring plates 50, 50 are mounted at transversely symmetrical positions uniformly to press the region towards both sides of the upper surface of the tape cassette 201 inserted and held on the holder framework 31, the aforementioned region corresponding to the shallow grooves 220, 220 formed in the tape cassette 201. A mating locking portion 53 is provided at the forward edge of the bottom plate 42 of the holder framework 31 so as to be engaged with a cassette holder lock lever constituting cassette holder locking means as later described. The mating locking memeber 53 is formed by a shaft 55 and a roller 54. The mating locking member 53 is so contructed and arranged that the roller 54 is fitted at the mid point of the shaft 55 so as to face to the middle of the front edge of the bottom plate 42, such that the locking position by the cassette holder lock lever is at the forward end edge at the widthwise centre of the cassette holder 3. At the middle and adjacent the forward edge of the bottom plate 42, there is formed a through-hole 56 into which is intruded the height position setting pin 9 mounted upright at the aforementioned tape cassette attachment position. On the upper surface of the holder framework 31, an upper surface protecting plate 57 is provided to protect the tape cassette 201 inserted and held on the holder framework 31. The tape cassette 201 is introduced, with the front cover 210 leading into the holder framework 31 of the cassette holder 3. As the tape cassette 201 is introduced along the surface of the bottom plate 42 of the holder framework 31, it is guided by the left and right edges and regulated by the bottom plate 42 and the cassette thrusting spring plates 50, 50. As the tape cassette 201 is introduced further into the holder framework 31, the ribs 49, 49 on the bottom plate 42 are engaged with the shallow grooves 220, 220 formed in the closure plate 214 of the tape cassette 201, so that the lock member 221 which retains the closure plate 214 on the cassette body 204 is thrust towards the inside of the cassette holder 3 to release the retention of the closure plate 214. The slide control projections 48, 48 at the rear end side of the bottom plate 42 abut on the lugs 215, 215 formed on the foremost part of the closure plate 214 to regulate the shifting of the closure plate 214. With the shifting of the closure plate 214 thus regulated, the tape cassette 201 is further introduced into the inside of the holder framework 31, so that only the cassette body 204 is shifted towards the inside of the holder framework 31. By the relative shifting between the cassette body 204 and the closure plate 214, the through-holes 212, 213 of the cassette body 204 and the through-holes 218, 218 of the closure plate 214 register with each other to expose or open the through-holes 212, 213. The position to which the cassette body 204 is introduced until the through-holes 212, 213 are exposed or opened represents the inserting and holding position for the tape cassette 201 into the holder framework 31, the through-holes 46, 46 in the bottom plate 42 then being in register with the through-holes 212, 213 to permit the reel shafts 5 and 6 to be engaged with the tape reels 205 and 206. The front cover 210 of the tape cassette 201 inserted and held in the holding framework 31, with the through-holes 212, 213 opened as described above, is unlocked by the relative shifting of the closure plate 214 and turned against the bias of the torsion coil spring 211, such that the front side, along which the magnetic tape 207 of the cassette body 204 is extended, may now be opened. The cassette holder 3, in which the tape cassette 201 is inserted and held as described above, is shifted to the tape cassette attachment position, when it is turned from the tape cassette inserting and detachment position shown in Figure 6 in a direction shown by the arrow A in Figure 6 against the bias of the torsion coil springs 38, 38. The tape cassette 201 inserted and held in the holder framework 31 is attached in position, as the attachment height position is regulated by the height position setting pin 9 and as the reel shafts 5, 6 are engaged with the tape reels 205 and 206. During the rotation of the cassette holder 3 to the tape cassette attachment position, the front cover 210 of the tape cassette 201 has its lower edge abutted on a cover opening member 58 provided on the mechanical chassis 2, so that the cover 210 is turned to open the front side of the cassette body 204 as shown in Figures 7 and 18 under the rotational urging force of the cover opening member 58 and against the bias of the torsion coil springs 21. The reel lock lever 226 is also shifted to unlock the tape reels 5 and 6 such that the magnetic tape 207 extended on the front side may be now pulled out by the loading mechanism or unit. On the front end side of the chassis 2, facing to the front end side of the cassette holder 3 shifted towards the tape cassette mounting position, there is provided a cassette holder locking mechanism 60 (Figures 1, 3, 4, 5, 6 and 7) which locks the cassette holder 31 at the tape cassette attachment position. The cassette holder locking mechanism 60 comprises a cassette lock lever 62 rotatably attached at the front of the chassis 2 and a locking member 61 provided to one side of the lock lever 62 and engageable with the mating locking portion 53 provided on the front edge of the cassette holder 3 that has been turned to the tape cassette attachment position, the locking member 61 thus locking the cassette holder 3 at the tape cassette attachment position. As shown in Figure 5, the lock lever 62 is formed by a pivotable rectangular plate 62 a having a central cut-out with the locking member 61 being formed integral with one side of the plate 62 a . Extending integrally from the upper edge of the other side of the plate 62 a is a spring retaining member 62 b . The proximal end side of the rotary plate 62 a is formed with journals 62 c , 62 c in which supporting shafts 63, 63 provided at the lower front end of the chassis 2 are journalled. On said one side of the rotary plate 62 a is protrudingly mounted a substantially U-shaped switch thrust member 65 to thrust and actuate a cassette holder lock sensor switch 64 to sense the locking state of the cassette holder lock lever 62 of the cassette holder 3. As shown in Figures 1 and 4, the cassette holder locking lever 62 is mounted for rotation in a direction orthogonal to the mating locking member 53 of the cassette holder 3, with the locking member 61 facing a position of engagement with the mating locking member 53 at the middle position in the left and right direction at the forward edge of the cassette holder 3 turned to the tape cassette attachment position, with the spring retaining member 62 b extending over the chassis frame 34 provided on one side of the mechanical chassis 2 and with the journals 62 c , 62 c of the rotary plate 62 a carried by the supporting shafts 63, 63 of the mechanical chassis 2. The foremost part of the spring retaining member 62 b is formed with a spring retaining tongue 62 d engaging one end of a tension coil spring 66 having its other end retained at a spring retaining member 34 a formed partway along the chassis frame 34, such that the cassette holder locking lever 62 is biased so as to be turned towards the cassette holder 3 so that the locking lever 62 is turned against the spring force of the tension coil spring 66, after which it is turned in the reverse direction for sustained engagement with the mating locking member 53 to lock the cassette holder 3. An ejection mechanism 67 (Figures 1, 8, 9, 10 and 11) to unlock the cassette holder 3 maintained in the locked state at the tape cassette attachment position by the cassette holder locking mechanism, is mounted through the intermediary of the chassis frame 34. As shown in Figures 1, 8 and 9, the ejection mechanism 67 comprises an ejection slide 68 reciprocable back and forth relative to the lock lever 62, an operating knob 69 for shifting the ejection slide 68 and a return spring 70 for the ejection slide 68 to urge the lever 68 in a direction away from the lock lever 62 as indicated by the arrow C in Figure 8. The ejection slide 68 is slidably mounted on the chassis frame 34 by slide guide pins 71, 71 mounted upright on the inner surface of the chassis frame 34 engaging in slide guide apertures 72, 72 each having its long axis extending lengthwise and with the foremost part of the slide 68 facing the spring retaining member 62 b of the locking lever 62 extending over the chassis frame 34. The operating knob 69 is mounted by a screw 73 to an attachment member 68 a formed by bending the upper end side of the ejection slide 68 and has its end knob 69 a extending out through a through-hole 74 formed in the outer casing 1. The ejection slide return spring 70 has one end retained in a spring engagement aperture 75 formed in the proximal end of the ejection slide 68 and has its other end retained in a spring retaining aperture 76 formed in the chassis frame 34 to bias the ejection slide in a direction away from the locking lever 62. The above described ejection mechanism 67 operates in such a manner that the operating knob 69 is actuated for shifting the ejection slide 68 towards the cassette holder locking lever 62 in the direction of the arrow D against the bias of the ejection slide return spring 70 to thrust the spring retaining member 62 b of the locking lever 62 by the end part of the ejection slide 68, so that the cassette holder locking lever 62 is turned in the direction of the arrow E in Figure 9 against the bias of the tension coil spring 66 to release the locking of the mating locking member 53 of the cassette holder 3 by the locking member 61 and to eject the cassette holder 3. It is noted that the operating knob 69 is provided at a position in which it is covered by the outer lid 4. The outer lid 4 may be opened and closed independently of the cassette holder 3. As shown in Figure 2, the outer lid 4 is in the form of a rectangle of a size sufficient to cover at least the cassette holder 3 locked in the tape cassette attachment position while also covering the operating knob 69 of the ejection mechanism 67. As shown in Figures 10 and 11, the lid is mounted with its rear edge journalled by a rotary shaft 77 to the outer casing 1 so as to cover the cassette holder 3 and be opened and closed as it is turned in the same direction as the rotational direction of the cassette holder 3. The outer lid 4 is connected by the intermediary of an outer lid opening and closure arm 81 to a rack plate 80 to actuate a loading start switch 79 of a loading mechanism which not only effects a loading operation for loading the magnetic tape 207 on a predetermined tape path but also rotates an ejection locking plate 78. The ejection locking plate 78 is operatively associated with the opening and closure of the outer lid 4 to lock the ejection lever 68 of the ejection mechanism 67 to inhibit the ejection operation or to unlock the ejection lever 68 to enable the ejection operation. Thus the outer lid opening and closure arm 81 interconnects the outer lid 4 and the rack plate 80 by having its one end journalled at a supporting shaft 82 upstandingly formed at the middle of the rack plate 80 and its other end journalled by a supporting shaft 84 upstandingly formed on an attachment member 83 provided towards the journal for the rotary shaft on one side of the outer lid 4. The rack plate 80 has its lower side edge formed with a rack 85 extending from the forward end towards the middle. An operating pin engaging member 87 engaging with a rotary pin 86 protuberantly formed on the ejection loading plate 78 depends from the forward end of the rack 85. the upper end facing the engaging member 87 is formed with a switch actuating member 88 to actuate the loading start switch 79. As shown in Figures 1 and 10, the rack plate 80 is slidably mounted for sliding in the fore and aft direction along the length of the chassis frame 34, with slide guide pins 91, 91 protuberantly formed on the inner side surface facing to the chassis frame 34 of a mounting plate 90 mounted to the outer lateral surface of the chassis frame 34 engaging with and supported by slide guide apertures 92, 92 each having its long axis extending longitudinally. The rack plate 80 is biased to be shifted towards the journal of the rotary shaft 77 of the outer lid 4 that is towards the rear of the mechanical chassis 2 as indicated by the arrow F in Figure 10 by a tension coil spring 95 installed between a spring retainer 93 formed at the middle of the lower side edge of the rack plate and another spring retainer 94 formed on the lower rear side edge of the mounting plate 90. The rack 85 of the rack plate 80 meshes with a pinion 97 formed on a spring damper 96 attached to the outer lateral surface of the mounting plate 90 and protruding via a through-hole formed in the mouting plate 90. In this manner, the rack plate 80 is prevented from recoiling acutely when the rack plate is resiliently returned after it is moved against the urging force of the tension coil spring 95. The outer lid 4 connected by the opening and closing arm 81 to the rack plate 80 biased towards the journal of the rotary shaft 77 of the outer lid 4 by the tension coil spring 95 and having the journal point of the arm 81 positioned towards the journal point to the rotary shaft 77 is perpetually biased under the shifting force of the rack plate 80 in the lid opening direction as directed by the arrow G in Figure 10. When the outer lid 4 is turned about the journal point on the rotary shaft 77 as centre so as to cover the cassette holder 3 that has been shifted to the tape cassette attachment position, the end of the opening and closure arm 81 adjacent the rack 80 is shifted in the direction of the arrow H in Figure 10 to slide the rack plate 80 in the same direction of the arrow H in Figures 10 and 11 against the force of the tension coil spring 95 rotationally to urge the spring damper 96 having its pinion 97 meshing with the rack 85. With the spring damper 96 rotationally biased during the lid closure operation, an urging force is stored in the spring damper 96 tending to oppose the tensile force of the tension coil spring 95 so that a moderate rotating movement of the outer lid 4 is ensured during the lid opening operation. When the outer lid 4 is closed to cover the cassette holder 3, a lid locking member 100 of an outer lid opening and closure mechanism 99 is engaged with a mating lid locking member 98 provided at one side of and towards the front of the outer lid to lock the outer lid 4 in the closed position. As shown in Figures 12A, B and C, the outer lid opening and closing mechanism 99 which can lock the outer lid 4 in the lid closure position is formed by a substantially L-shaped lid locking member 100 including a lock pawl 100 a engaging with the mating lid locking member 98 of the outer lid 4 and a rotary member 100 b and by an opening and closure member 101 whereby the lid locking member 100 can be turned to unlock the outer lid 4. The lid locking member 100 is mounted with the rotary member 100 b facing the mating lid locking member 98 of the outer lid 4 in the closed position, and having a journal position 100 c journalled on a supporting shaft 102 provided on the outer casing 1, such that the member 100 is rotationally urged by a torsion coil spring (not shown) in a direction in which the lock pawl 100 a is engaged with the mating lid locking member 98. The opening and closure member 101 is slidably supported on the outer casing 1 by having its knob 101 a protruding from a through-hole 105 formed in the upper side of the outer casing 1, as shown in Figure 2 and by having a rotary member 101 b on the lower side of the outer casing 1 positioned for facing the rotary member 100 b of the lid locking member 100. Also, as shown in Figure 12A, a compression coil spring 103 operatively linked with the outer casing 1 is operatively linked with the opening and closure member 101 so that the member 101 is biased to be shifted in a direction shown by the arrow I in Figure 12A in which the rotary member 101 b is moved away from the rotary member 100 b of the lid locking member 100. It is noted that the shifting position of the operating knob 101 is limited by a position regulating member protuberantly formed on the outer casing 1. In the above described outer lid opening and closure mechanism 99, when the outer lid 4 is turned to the lid closing position, the locking pawl 100 a of the lid locking member 100 is engaged with the lid locking member 98 to lock the outer lid 4. When the operating knob 101 is moved against the urging force of the compression coil spring 103, an inclined surface 101 c of the rotary member 101 b acts upon the rotary member 100 b of the lid locking member 100, as shown in Figure 12C, such that the lid locking member 100 is turned in a direction in which the locking pawl 100 a is moved away from the mating lid locking member 98 to unlock the outer lid 4. When the outer lid 4 is unlocked by the operation of the operating knob 101, the outer lid 4 is automatically returned to the lid opening position under the urging force of the tension coil spring 95 biassing the rack plate 80. The mounting plate 90 is mounted to the chassis frame 34 by having a mating engaging member 90 a (Figure 1) protuberantly formed on the lower side edge of the plate 90 and engaged in an engaging aperture 89 a of an engaging member 89 protuberantly formed on the chassis frame 34 by having a screw mounting member 90 b protuberantly formed on the upper side edge of the plate 90 threaded to a mating screw member 89 b on the chassis frame 34 by a screw 90 c . The ejection locking plate 78 of the ejection locking mechanism is mounted on the outer side surface of the chassis frame 34 in the vicinity of the ejection lever 68 on which the mounting plate 90 mounting the rack plate 80 is mounted. As shown in Figures 1, 8 and 9, the ejection locking plate 78 is substantially sector-shaped and has a through-hole 111 at the proximal end into which a journal shaft 110 is introduced. On one forward end opposite the through-hole 111 is formed a retaining member 113 to engage a mating engaging member 112 protuberantly formed on the forward lower side edge of the ejection slide 68. On the other side of the plate 78 opposite to the retaining member 113 is formed the rotary pin 86 projecting in a direction opposite to the projecting direction of the retaining member 113 for engagement with the engaging member 87 provided on the forward end of the rack plate 80. The ejection locking plate 78 is rotatably mounted on the chassis frame 34 with the retaining member 113 passed through a substantially sector-shaped opening 114 formed in the chassis frame 34 facing the engaging member 112 of the ejection slide 68 and with the rotary pin 86 engaging with the pin 87, the journal shaft 110 being passed through the through-hole 111. A tension coil spring 116 having one end retained by a spring retainer 115 formed on the forward end of the mechanical chassis 2 has its other end retained by a spring retainer 117 extending in a direction opposite to the projecting direction of the rotary pin 86, so that the ejection locking plate 78 is rotationally biassed in the direction shown by arrow J in Figure 8 in which the retaining member 113 is engaged with the engaging member 112 of the ejection slide 68. Thus, in a state in which the ejection locking plate 78 is not turned against the urging of the tension coil spring 116, the shifting of the ejection slide 68 in the direction shown by the arrow D in Figure 9 against the ejection lever return spring 70 is inhibited to disable the rotation of the locking lever to inhibit the ejection of the cassette holder 3. When the outer lid 4 is opened and the rack plate 80 is shifted towards the front of the chassis 2 as indicated by the arrow H in Figure 11 against the urging force of the tension spring 95, the rotary pin 86 is turned by the rotary pin engaging member 87 and the ejection locking plate 78 is turned about the journal shaft 110 as indicated by the arrow K in Figure 9, the engaging member 113 disengaging from the engaging member 112 of the ejection slide 68 to permit the sliding of the ejection slide 68. In this manner, the lock lever 62 may be turned to eject the cassette holder 3. The rotary magnetic head type audio PCM tape recorder includes an unlocking inhibit mechanism 118 (Figures 3, 4, 13 and 14) to inhibit unlocking of the cassette holder locking mechanism 60 to inhibit ejection of the cassette holder 3 and taking-out of the cassette holder 3 during the operation of the loading mechanism, that is, during loading and unloading of the magnetic tape 207, and when the tape 207 has been loaded onto the tape path. As shown in Figure 13, the unlocking mechanism 118 comprises a rotary inhibit lever 120 engaging one side of a cut-out 119 formed in the pivotable plate 62 a of the cassette holder locking lever 62, and a shifting lever 121 to rotate the rotation inhibit lever 120 by being shifted by rotation of the loading rings 17 and 18 to shift the loading mechanism including the shift guides 11 and 12 for loading the magnetic tape 207. As shown in Figures 3 and 13, the rotation inhibit lever 120 is substantially L-shaped and has an end locking pawl 120 a positioned within the cut-out 119 in the pivotable plate 62 a of the cassette holder locking member 62 and rotatably supported by a supporting member 122 protuberantly formed on the lower surface of the mechanical chassis 2. The rotation inhibit lever is mounted so as to be rotationally biassed in the direction indicated by the arrow L in which the lock pawl 120 a is engaged in the cut-out 119 by a torsion coil spring 123 placed around the shaft 122. The shifting lever 121 is slidably mounted parallel to the longitudinal direction of the chassis frame 34 with an end rotary member 121 a for the rotation inhibit lever positioned facing a mating rotary member 120 b protuberantly formed on the other end of the rotation inhibit lever 120, with a mating thrust member 121 b at the proximal end positioned facing the rotary trajectory of a shifting pin 124 protuberantly formed on the loading ring 17 and with a slide guide shaft 126 protuberantly formed on one side on the lower surface of the mechanical chassis 2 engaging in a slide guide aperture 125 having a longer axis extending longitudinally. The shifting lever 121 is biassed so as to be shifted by a tension coil spring 127, having one end retained by the mechanical chassis 2, in a direction in which the end rotary member 121 a of the rotation inhibit lever is spaced apart from the mating rotary member 120 b at the other end of the rotation inhibit lever 120 as indicated by the arrow N in Figure 13. One of the shifting pins 124 is mounted on the loading ring 16 at a position in which, when the shift guides 11 and 12, the pinch roll supporting arm 26, the tape guide supporting arm 26, the tape guide supporting arm 28 and the tension regulating arm 30 are in an inoperative state of not loading the magnetic tape 207, the shifting pin 124 thrusts the mating thrusting member 121 b to shift the shifting lever 121 against the force of the tension coil spring 127 to cause the shifting lever 121 to be turned in a direction to disengage the locking pawl 120 a of the rotation inhibit lever 120 from the cassette holder locking lever 62. In the above described unlocking inhibit mechanism 118, when the loading ring 17 is turned in a direction shown by the arrow R in Figure 13 in which the shift guides 11 and 12 and other related units are moved towards the rotary magnetic head device 10 to pull the tape 207 out of the tape cassette 201, the shifting pin 124 is shifted away from the mating thrusting member 121 b of the shifting lever 121. The lever 121 is shifted in a direction indicated by the arrow N in Figure 13 under the bias of the tension coil spring 127 and the end rotary member 121 a is shifted away from the rotary member 120 b of the rotation inhibit lever 120, which is rotationally urged in the direction of the arrow L in Figure 13 under the force of the torsion coil spring 123, the locking pawl 120 a being thus engaged with the pivotable plate 62 a of the cassette holder locking lever 62 to lock the cassette holder locking lever 62 to inhibit the rotation. Thus, in the state in which the loading mechanism is energized, with the tape 207 pulled out onto the tape passage out of the tape cassette 201, the cassette holder locking lever 62 is locked to inhibit the ejection of the cassette holder 3. The recorder includes a tape cassette attachment sensor mechanism (Figures 6, 7, 14 and 15) that enables driving of the loading motor 21 rotationally driving the loading rings 17 and 18 to actuate the loading mechanism, on the condition that it has been sensed that the cassette holder 3 accommodating and holding the tape cassette 201 therein is locked at the tape cassette attachment position and the tape cassette 201 is attached at the tape cassette attachment position, in order to prevent troubles or defects in the loading of the magnetic tape 207 or an injury to unite such as the loading mechanism or the magnetic tape 207, caused by the actuation of the loading unit in the state in which the tape cassette 201 is not attached correctly at the tape cassette attachment position. The tape cassette attachment sensor mechanism comprises the cassette holder locking sensor switch 64 actuated by the cassette holder locking lever 62 when the cassette holder 3 is locked by the lever 62 to sense attachment sensor switches 128, 128 actuated by the tape cassette 201 when the tape cassette is attached at the tape cassette attachment position to sense the attachment of the tape cassette 201. The cassette holder locking sensor switch 64 is mounted at the forward end of the mechanical chassis 2 and, as shown in Figure 6, it is mounted so that a pair of contact actuating members 129 a , 129 b are engaged with the inner lateral sides of the switch thrust member 65 protuberantly formed on one side of the cassette holder locking lever 62. When the cassette holder locking lever 62 is not turned against the urging force of the tension coil spring 66 and is erected upright with respect to the mechanical chassis 2, the contact actuating member 129 a is thrust by the switch thrust member 65, as shown in Figure 6, to contact with the other contact actuating member 129 b to hold the turn-on state of the cassette holder locking sensor switch 64. The tape cassette attachment sensor switches 128, 128 are provided at positions transversely symmetrical with respect to the height position setting pin 9 on the mechanical chassis 2 as centre and in registration with cut-outs 42 a in the opposite sides on the forward end side of the bottom plate 42 of the cassette holder 3. At these positions, the switches 128 can be actuated by the rear bottom surface protuberant from the cassette holder 3 of the tape cassette 201 inserted into and held within the cassette holder 3. When the cassette holder locking lever 62 is not actuated, the cassette holder locking sensor switch 64 is in the turn-off state, as shown in Figure 15. When the cassette holder 3 is turned towards the tape cassette attachment position, so that the locking member 62 is thrust by the mating locking member 53, the cassette holder locking lever 62 being turned a predetermined angle as shown in Figure 14 against the urging of the tension coil spring 66, the contact actuating member 129 a is released from engagement with the switch thrusting member 65, so that the switch 64 is turned off, as shown in Figure 15. When the cassette holder 3 is turned towards the tape cassette attachment position, so that the locking state of the cassette holder 3 is reached in which the mating locking member 53 is engaged with the locking member 62, the locking member 62 is returned under the biassing force of the tension coil spring 66, the switching thrusting member 65 again thrusts the contact actuating member 129 a , so that the cassette holder lock sensor switch 64 is turned on, as shown in Figure 15. Thus the cassette holder lock sensor switch 64 senses the locked state of the cassette holder 3 by the cassette holder 62 when the switch 64 is again turned on after it has been turned off by the rotation of the cassette holder 3 towards the tape cassette attachment position. On the other hand, when the cassette holder 3 is turned slightly as shown in Figure 14 after it is turned towards the tape cassette attachment position, the cassette holder 3 then turning the cassette holder lock sensor switch 64 momentarily off, the actuating member 128 a is thrust by the tape cassette 201 inserted and held in the cassette holder 3, so that the switches are turned on as shown in Figure 15 by the engagement by the tape cassette 201. At this time, both switches 128, 128 are thrust to issue tape cassette attachment detection outputs. Since it is when both of the tape cassette attachment sensor switches 128, 128 mounted at the transversely symmetrical positions are thrust that the tape cassette attachment output signals are issued, attachment of the tape cassette 201 at the correct tape cassette attachment position can be sensed accurately. The operation of the loading motor 21 is enabled only when both outputs of the tape cassette attachment sensor switches 128, 128 and the cassette holder locking sensor switch 64 are obtained simultaneously. A loading start actuating mechanism (shown in Figures 1, 10 and 11) is provided. The loading motor 21 is driven into rotation when the outer lid 4 that may be turned independently of the cassette holder 3 is closed after the attachment of the tape cassette 201 at the tape cassette attachment position. Thus the loading start switch 79 actuated by the rack plate 80 shifted by the opening and closure of the outer lid 4 is mounted by the intermediary of the mounting plate 90. This loading switch 79 is mounted at a position in which, when the outer lid 4 is closed and the rack plate 80 is shifted with the operating member 79 a facing the switch thrusting member 88 of the rack plate 80 via through-hole 106 formed in the mounting plate 90, the operating member 79 a is thrust by the switch thrusting member 88. By providing the loading start switch 79 actuated in connection with the closure of the cassette holder 3 by the outer lid 4, the operation of the loading mechanism can be started by the reliable operation after the termination of attachment of the tape cassette 201 at the tape cassette attachment position. The operation of attaching the tape cassette 201 and that of loading the tape 207 contained in the tape cassette 201 in the rotary magnetic head type audio PCM tape recorder will now be explained. When attaching the tape cassette 201 at the tape cassette attachment position, the opening and closure member 102 of the outer lid opening and closure mechanism 99 is actuated for setting the outer lid 4 to the open position as shown in Figures 2 and 10. When the outer lid 4 is opened the rack plate 80 is shifted by the tension coil spring 95 as shown in Figures 9 and 10, to enable shifting of the ejection slide 68. At this time, the ejection slide 68 is shifted for turning the cassette holder lock lever 62 against the urging force of the tension coil spring 66 to restore the cassette holder 3 to the ejection position as shown in Figure 6. At this time, the loading rings 17 and 18 are in the inoperative position in which the rings 17 and 18 have displaced the loading mechanism including the shifting guides 11, 12 towards the tape attachment position. The loading rings 17 and 18 in this position pressure the shift lever 121 to cause the rotation inhibit lever 120 to be turned against the force of the torsion coil spring 123 to disengage the lever from the cassette holder lock lever 62. After the cassette holder 3 is ejected in the above described manner, the tape cassette 201 is introduced into the cassette holder 3. When the tape cassette 201 is inserted from the front lid 210, the closure plate 214 being shifted for opening the through-holdes 212, 213 on the bottom surface of the cassette body 204 to enable the turning of the front cover 210, the tape reels 205 and 206 are unlocked and are maintained in the predetermined inserting and holding position in the rotation-enabled state. The cassette holder 3 accommodating and holding the tape cassette 201 is turned towards the tape cassette attachment position until the mating locking member 53 is locked to the cassette holder lock lever 62 as shown in Figure 7. When the cassette holder 3 is turned to the tape cassette attachment position, the front cover 210 is turned by the lid opening member 58 to opening the front side of the cassette body 204 to enable the magnet tape 207 to be pulled out by the loading mechanism. Also the reel shafts 5, 6 mounted at the tape cassette attachment position are engaged with the tape reels 205 and 206 to enable the rotation of the tape reels. At this time, when the cassette holder 3 is locked to the cassette holder lock lever 62 and the tape cassette 201 is attached correctly with the height level correctly set by the height level setting pin 9, the locking of the cassette holder 3 and the attachment of the tape cassette 210 are sensed by the cassette holder locking sensor switch 64 and the tape cassette attachment sensor switches 128, 128 to enable starting of the operation of the loading mechanism, as described hereinabove. After the tape cassette 201 is attached to the tape cassette attachment position, the outer lid 4 is closed to cover the cassette holder 3, as shown in Figure 11. When the outer lid 4 is closed, the rack plate 80 connected to the outer lid 4 by the medium of the outer cover 81 is shifted against the bias of the tension coild spring 95 so that the ejection locking plate 78 is engaged with the ejection slide 68, as shown in Figure 8, to inhibit the operation of the ejection slide 68 and disabling the ejection of the cassette holder 3. Therefore, once the outer lid 4 is turned to the vicinity of the lid closing position, an ejection operation may be performed by the ejection lever 68. When the outer lid 4 is closed, the lock start switch 79 is actuated by the switch thrusting member 88 provided on the rack plate 80 as shown in Figure 11 to start the rotation of the loading motor 21. When the loading motor 21 is driven for rotation, the loading reels 17 and 18 are driven for rotation so that the loading mechanism including the shifting guides 11 and 12 are actuated to pull the magnetic tape 207 out of the tape cassette 201 to cause the tape to be delivered to the predetermined tape passage to effect loading. It should be noted that, when the loading motor 21 is driven into rotation such that the loading rings 17 and 18 are turned, the shifting lever 121 is released from engagement by the shifting pin 124, as shown in Figure 13. The shifting lever 121 is shifted by the torison coil spring 127, as shown in Figure 13, to release the rotational bias of the rotation inhibit lever 120. The rotation inhibit lever 120 is turned bythe torsion coil spring 123 so as to be engaged with the cassette holder lock lever 62 to inhibit the rotation of the cassette lock lever 62. This state is continued until the loading rings 17 and 18 cause the loading mechanism including the shifting guides 11 and 12 to be again returned to the inoperative position towards the tape cassette attachment position. In the above embodiments, the present invention is explained by taking an example of a rotary magnetic head tape audio PCM tape recorder. However, the present invention may be applied extensively to other forms of cassette type magnetic recording/reproducing apparatus wherein a tape cassette is used as the recording medium and a tape cassette transfer member such as a cassette holder holding the tape cassette is moved from a tape cassette inserting and detaching position to a tape cassette attachment position to attach a tape cassette at the predetermined tape cassette attachment position.

Claims: A cassette type magnetic recording/reproducing apparatus, comprising: a cassette holder (3) supported for movement between a tape cassette inserting and detachment position and a tape cassette attachment position; locking means (62) to lock the cassette holder (3) in the tape cassette attachment position; tape loading means (10 to 30) to pull a magnetic tape (207) accommodated within a tape cassette (201) held at the tape cassette attachment position out of the tape cassette (201) to load it onto a predetermined tape running path; and tape cassette attachment sensor means (128, 128) to sense when a tape cassette accommodated and held in the cassette holder (3) is attached at the tape cassette attachment position; characterised by cassette holder lock sensor means (64) to sense when the cassette holder (3) is locked in the tape cassette attachment position; and means to actuate the tape loading means (10 to 30) only when the locking of the cassette holder (3) is sensed by the cassette holder lock sensor means (64) simultaneously with the sensing of tape cassette attachment by the tape cassette attachment sensor means (128). A cassette type magnetic recording/reproducing apparatus according to claim 1, wherein the cassette holder lock sensor means includes a first sensor switch (64) actuatable by locking of the locking means (62). A cassette type magnetic recording/reproducing apparatus according to claim 1, wherein the tape cassette attachment sensor means includes a second sensor switch (128) actuatable by the tape cassette when the tape cassette is attached at the tape attachment position. A cassette type magnetic recording/reproducing apparatus according to claim 3, wherein the sensor means includes at least a pair of the second sensor switches (128). A cassette type magnetic recording/reproducing apparatus according to claim 1, including an outer lid (4) provided so as to be openable and closeable independently of the cassette holder (3) and when closed to cover at least the cassette holder (3) in the tape cassette attachment position; outer lid sensor means (79) to sense a closed state of the outer lid (4); and loading starting means to start loading of the magnetic tape by the tape loading means and operable when the outer lid sensor means (79) senses the closure of the outer lid (4). A cassette type magnetic recording/reproducing apparatus according to claim 5, wherein the outer lid sensor means includes a rack plate (80) provided so as to be shiftable by closure of the outer lid, and a third sensor switch (79) actuatable by shifting of the rack plate (80). A cassette type magnetic recording/reproducing apparatus according to claim 5 wherein the loading starting means is actuated only when the closure of the outer lid (4) is sensed by the outer lid sensor means (79) under the condition that the locking of the cassette holder (3) and attachment of the tape cassette are sensed by the cassette holder lock sensor means (64) and the tape cassette attachment sensor means (128), respectively. A cassette type magnetic recording/reproducing apparatus according to claim 1, including an outer lid (4) provided so as to be openable and closeable independently of the cassette holder (3) and to be closed to cover at least the cassette holder (3) in the tape cassette attachment position; ejection means (68) to eject the cassette holder; and ejection inhibit means (28) shiftable in association with the opening and closing of the outer lid (4) and engageable with the ejection means (68) when the outer lid (4) reaches the vicinity of a lid closure position to inhibit ejection by the ejection means.

Inventors: HAZIME IKEDA, HAZIME, IKEDA
Applicants: SONY CORP, SONY CORPORATION
Application year: 1988
Main classification: G11B15
IPC codes: G11B15