A tape cassette having outer and inner lids locked by the inner lid

Abstract: A tape cassette of the type having front (13) and back (25) lids for covering front and rear sides of a run of the cassette tape (7) which passes outside of the cassette casing is further provided with a locking element for locking the back lid closed when the cassette is not being used.

Description: The present invention generally relates to tape cassettes and, more particularly, to a tape cassette having a lid arrangement for selectively covering the tape inside the cassette when it is not in use and exposing the tape to allow a run of the tape to be withdrawn to the exterior of the cassette casing to extend along a tape withdrawing area between tape exit portions formed at two ends of a front wall of the cassette casing. More particularly, the invention relates to a tape cassette in which the lid arrangement has a front lid, which faces the exterior and a rear lid, which is located behind the run of tape when the lids are closed. In one type of tape cassette utilising a record medium tape, for example, a magnetic tape, having such a lid arrangement, the front lid is rotatably attached to the cassette casing so that the front lid is moveable between a lid closed position for covering the front wall of the 7049cassette casing, and a lid opened position for exposing the front wall. The front lid functions to protect the tape, which extends along the front wall of the cassette casing, from dust and from being touched by the fingers and the like. The front lid is commonly comprised of a main portion which covers the front wall of the cassette casing. Supporting portions protrude from left and right ends of the main portion and are rotatably supported by the left and right side wall portions of the cassette casing. This type of conventional tape cassette is provided with a tape withdrawing recess portion open in the front and lower directions in order to place a tape withdrawing member behind the tape when the tape cassette is loaded on the recording and/or reproducing apparatus. The tape withdrawing recess portion is formed between two tape exit portions provided at left and right end portions of the front wall of the cassette casing. The rear lid is to protect the tape from being touched with fingers or the like entered through the tape withdrawing recess portion, a conventional tape cassette is provided with a back lid which covers the tape from the rear side independently from the front lid. Because the front lid functions to protect the tape when the tape cassette is not in use, the front lid must be locked in the lid closed position. To this end, this type of tape cassette is generally provided with a locking device which locks the front lid in the lid closed position. In the prior art tape cassette, one side end portion of the front lid, for example, one of the left and right supported portions is locked by the locking device. Japanese utility model published gazette number 63-1606 describes a tape cassette having such a locking device. However, with respect to the configuration of the tape cassette, the dimension in; the left to right direction is large compared to the thicypess, as seen from the front wall side. Accordingly, the main portion of the front lid is generally shaped in a narrow rectangular configuration that is long in the left to right direction. Therefore, the mechanical strength of the front lid against deformation is decreased. As a result, if the other side end portion of the front lid is pushed in the lid opening direction, without releasing the front lid from its locked state, the other side end portion of the front lid is displaced while the front lid is twisted, exposing one portion of the tape to the outside. Further, there is the substantial disadvantage that the front lid may be deformed or damaged. Measures to reduce the above mentioned shortcomings and disadvantages include increasing the thickness of the front lid and locking the front lid locked at both its left and right side portions. According to this proposal, the weight of the tape cassette is increased or the number of locking devices is increased, which unavoidably increases the number of assembly parts of the tape cassette. Further, another problem is that the number of lock releasing devices provided in the recording and/or reproducing apparatus must be increased in order to release the locking device. EP 129884 shows a number of locking mechanisms used in this situation and which suffer from the disadvantages listed above. The pre-characterising portion of claim 1 is based on these disclosures. Accordingly, it is an object of the present invention to provide an improved tape cassette which can reduce or eliminate the aforenoted shortcomings and disadvantages encountered with the prior art. According to the present invention, there is provided a tape cassette having a cassette casing and a tape in use of which cassette the tape is to be withdrawn to the outside of the cassette casing such that a tape run having front and rear sides extends along a tape withdrawing area between tape exit portions formed at two end portions of a front wall of the cassette casing, and including a front lid rotatably attached to the cassette casing so as to cover the whole area of the front wall of the cassette casing, a back lid rotatably attached to the front lid so as to substantially cover the rear side of the tape run, the front and back lids being mounted in the cassette for movement between an open position allowing access to the tape run when the cassette is in use, and a closed position wherein the front and rear sides of the tape run are substantially covered by the front and back lids when the tape cassette is not in use, and locking means for locking the back lid in the closed position when the tape cassette is not in use, characterised in that the locking means comprise at least one guide pin formed on the back lid, the cassette casing including a corresponding guide groove for receiving the guide pin a lower end of the guide groove including an over-centre locking surface whereby the guide pin is locked. Thus, in the tape cassette of the present invention, a locking member locks the front and back lids in the lid closed positions, so that, without increasing the thickness of the front lid, the mechanical strength of the front lid to resist deformation is increased. Therefore, the lid closed condition can be maintained stably and the front lid can be prevented from being deformed. The invention will be further described by way of non-limitative example with reference to the accompanying drawings, in which:- Figures 1A-1C are fragmentary, enlarged, longitudinal cross-sectional views of a main portion of a first embodiment of a tape cassette according to the present invention. Reference will be made to these figures in explaining the movements of front and back lids from their closed positions to their opened positions with the passage of time. Figure 2 is an enlarged, perspective view of the first embodiment of the tape cassette according to the present invention with its front and back lids closed. Figure 3 is an enlarged, perspective view of the first embodiment of the tape cassette according to the present invention with its front and back lids opened. Figure 5 is an enlarged, cross-sectional view taken through the line IV-IV in figure 1A, illustrating the first embodiment of the tape cassette. Sections of the cassette have been omitted for simplicity. Figure 6 is an enlarged, partial cutaway, perspective view of the back lid and the front lid, illustrating, particularly, two end portions of the back lid and a supporting portion of the front lid. The present invention will now be described in detail with reference to the accompanying drawings. Figures 1A-6 show an embodiment of the tape cassette according to the present invention. Initially, a cassette housing or casing of this tape cassette will be described with reference to figures 1A-5. As illustrated, a tape cassette is provided which is generally designated by reference numeral 1. A cassette casing 2 of the tape cassette 1 is shaped substantially as a planar, rectangular thin box and is generally comprised of an upper half or upper part 3 and a lower half or lower part 4. The cassette casing 2 has a substantially rectangular shallow-shaped configuration and is made of a synthetic resin. The upper part 3 and the lower part 4 are secured together by a suitable means such as screws (not shown) or the like. As shown in Fig. 2, a pair of tape reels 5 and 6 are rotatably accommodated within the cassette casing 2, and a magnetic tape 7, as shown in Fig. 3, is wrapped around the pair of tape reels 5 and 6. As illustrated in Fig. 3, tape exit portions 8 and 8′, respectively, are provided at right and left end portions of a front wall 2a of the cassette casing 2. The magnetic tape 7 supplied from one tape reel 5 is withdrawn from the tape exit portion 8 to the outside of the cassette casing 2. Then, the magnetic tape 7 travels along a portion between the tape exit portions 8 and 8′ (this portion will be referred to hereinafter as the "tape withdrawing area"). The tape 7 then enters the cassette casing 2 from the other tape exit portion 8′, finally winding around the other tape reel 6. A tape withdrawing recess portion 9 is formed in the above-mentioned tape withdrawing area along the front wall 2a portion of the cassette casing 2. The tape withdrawing recess portion 9 has a front surface 10, a lower surface 11 and an upper surface 12, as shown in Figs. 1A - 1C. The depth of the upper opening surface 12 is small compared to the lower opening surface 11. A rear edge 12a of the upper opening surface 12 extends in the left to right direction in a straight line fashion, as shown in Fig. 5. Other configurations and structures of the cassette casing 2 will be described more fully later. An outer or front lid will be described with reference to Figs. 1A - 6. As illustrated, an outer or front lid 13 is made of a synthetic resin and covers the whole area of the front wall 2a of the cassette casing 2. The front lid 13 is comprised of a front wall portion 14, an upper wall portion 15 protruding rearward from the upper edge of the front wall portion 14, and side wall portions 16, 16′ protruding rearward from the left and right side edges of the front wall portion 14. The front lid 13 is unitarily formed by a molding-process of a synthetic resin. As shown in Figs. 4 and 5, support pins 17 and 17′ are implanted on the inside surfaces of the side wall portions 16 and 16′. The pins are substantially centrally positioned relative to the upper to lower direction, near the rear of their respective side wall portions. The support pins 17 and 17′ are rotatably supported by support apertures 18 and 18′ formed through the side portions of the cassette casing 2 near the front ends, whereby the front lid 13 is rotatably supported by the cassette casing 2 in such a fashion that the front lid 13 is rotated between the closed position, in which the front wall portion 14 of the front lid 13 covers the front wall 2a of the cassette casing 2, as shown in Fig. 2, and the opened position, in which the front wall portion 14 is located on the upper side of the front wall 2a exposing the front wall 2a as shown in Fig. 3. As illustrated, a torsion spring 19 is provided to urge the front lid 13 to rotate in the lid closing direction. The torsion spring 19 is comprised of a spring coil portion 19a and two spring arm portions 19b and 19c which separately extend from the two ends of the spring coil portion 19a. The spring coil portion 19a is engaged with the support pin 17 between the front lid left side wall portion 16 and the cassette casing 2. In the foregoing, the "left-hand direction" means the left-hand direction when viewing the front wall of the tape cassette 1. As best shown in Fig. 1A, one spring arm portion 19b comes in downward, resilient contact with a spring contact portion 20 which protrudes from the inside surface of the side wall portion 16 between the front wall portion 14 side and the support pin 17. The other spring arm portion 19c comes in downward, resilient contact with a spring contact portion 21 which protrudes from the left side surface of the cassette casing 2. Thus, the torsion spring 19 urges the front lid 13 to rotate in the counter-clockwise direction as seen from the right-hand side, i.e. the lid closing direction. Left and right end portions 22a of the front end of a bottom plate portion 22 of the cassette casing 2 protrude slightly forward from the front wall 2a of the cassette casing 2. Further, shallow recesses 14a are formed on the lower side edge of the front surface portion 14 of the front lid 13 so that, when the upper side edges of the recesses 14a and 14b come in downward contact with the protruding portions 22a, the front lid 13 is inhibited from excessively rotating in the counter-clockwise direction. A back lid 25 inhibits the rotation of the front lid 13, when the front lid is in the closed position. Therefore, when the front lid 13 is in the closed position (this condition will be referred to hereinafter as "lid closed condition"), the whole area of the front wall 2a of the cassette casing 2 is covered by the front surface portion 14 of the front lid 13, and the upper surface opening 12 of the tape withdrawing recess portion 9 is covered by the upper surface portion 15 of the front lid 13. Accordingly, the magnetic tape 7 which extends along the tape withdrawing area of the front wall 2a of the cassette casing 2, is covered at its front surface side and upper portion by the front lid 13. As best shown in Figs. 1C and 5, support members 23 are provided to support the back lid 25 which will be described later. These support members 23 extend downward from the undersurface of the upper surface portion 15 of the front lid 13. The lower ends of these support members 23 extend to a position slightly above the center of the front lid 13 in its upper to lower direction. In the left to right direction of the front lid 13, the lower ends of the support members 23 are located at the positions corresponding to opposing inner side surfaces 24a of walls 24 located at left and right inside surfaces of the tape withdrawing recess portion 9. These positions are between the tape withdrawing recess portion 9 and the tape exit portions 8 and 8′. Circular support apertures 23a are bored through the lower end portions of the support members 23. Spring contact portions 23b protrude inward from the upper portions of the front side edges of the support members 23. The inner or back lid 25 will be described with reference to Figs. 1A - 1C and Figs. 3 - 6. As illustrated, the back lid 25 covers the rear and lower sides of the magnetic tape 7. Portions of the back lid 25 are formed by a molding-process of a synthetic resin. A main portion 26 of the back lid 25 is shaped as a rectangular plate, long in the left to right direction. The main portion 26 has a length substantially the same as the spacing between the two support members 23 of the front lid 13. The back lid main portion 26 has an upper to lower width that is slightly smaller than the upper to lower width of the front surface portion 14 of the front lid 13. The back lid 25 has a protruding portion 26b which has an arc-shaped configuration in transversal cross section, as shown in Fig. 6. Portion 26b protrudes from the back lid rear wall 26a at a position slightly above the center in the width direction. The back lid main portion 26 is substantially V-shaped in cross-section above the protruding portion 26b, as viewed from the left. Recesses 26c are respectively formed on the back lid main portion 26 at positions corresponding to the protruding portion 26b. The recesses are in the left and right side end faces of the main portion 26. Two coaxial support pins 27 protrude from the side surfaces of the recesses 26c. An outwardly jutting lip 28 along the lower side edge of the front surface of the main portion 26 of the rear door 25, extending in the left to right direction. Relatively short arm members 29 protrude rearward from the lower ends of the left and right ends of the main portion 26 of the back lid 25. Guided pins 30 of small columnar-shaped configurations, protrude from the rear portions of the arm members 29 in the lateral direction. Downwardly extending bosses 31 protrude from the left and right end portions of the main portion 26. The height between the lower surface of the bosses 31 and the upper surface of the main portion 26 is made very slightly smaller than the height between the lower edge of the front surface portion 14 of the front lid 13 and the undersurface of its upper surface portion 15. The support pins 27 are inserted into the support apertures 23a formed through the support members 23 of the front lid 13, whereby the back lid 25 is rotatably supported by the front lid 13 at a position behind the front surface portion 14 of the front lid 13. Further, the guided pins 30 are slidably engaged with guide grooves (which will be described later) formed in the side walls of the cassette casing 2, whereby the back lid 25 is movable between the lid closed position shown in Fig. 1A, and the lid opened position shown in Fig. 1C, in unison with the rotation of the front lid 13. Torsion springs 32 urge the back lid 25 to rotate in the direction in which the lower end portion of the back lid 25 approaches the front lid 13. The torsion springs 32 are comprised of spring coil portions 32a and two spring arm portions 32b and 32c which separately extend from the two ends of the spring coil portions 32a. The spring coil portions 32a are engaged with the support pins 27 at positions between the main portion 26 and the support members 23. Spring arm portions 32b are in resilient contact at their free ends, with the spring contact portions 23b of the support members 23 from the rear direction. The other spring arm portions 32c are in resilient contact at their tip ends, with the front surface of the main portion 26 at positions which are continuous with the upper side surfaces of the recesses 26c from the front side. Thus, the back lid 25 is urged to rotate in the clockwise direction, as seen from the right-hand direction, by the torsion springs 32. The guide grooves 33 will be described next with reference to Figs. 1A - 1C and Figs. 3 - 5. As illustrated, guide grooves 33 guide the movement of the guided pins 30, thereby controlling the attitude of the back lid 25 relative to the front lid 13. In addition to the above-mentioned guide function, the guide grooves 33 have a locking function to lock the back lid 25 at the lid closed position. Portions 33a protrude from the inside surfaces 24a of the cassette casing walls 24 forming the guide grooves 33. The guide grooves 33 are comprised of initial guide portions 34, forming the lower end portions thereof, succeeding intermediate portions 35 and succeeding final guide portions 36. The initial guide portions 34 are substantially flush with the lower side edge of the magnetic tape 7 extended along the tape withdrawing area of the front wall 2a of the cassette casing 2. Also, the initial guide portions 34 are formed so as to extend substantially along a rotational loci of the guided pins 30 of the back lid 25 when the front lid 13 is in the lid closed position. The intermediate portions 35 continuously extend upward in a substantially straight line fashion from the rear end portions of the initial guide portions 34. Further, the final guide portions 36 extend, in the form of a gentle arc in the clockwise direction as seen from the right hand side, from the upper ends of the intermediate portions 35. The upper ends of the final guide portions 36 are open at substantially the same level as the tops of the walls 24. The guided pins 30 of the back lid 25 are slidably engaged with the guide grooves 33, resulting in the movement of the guided pins 30 being defined by the guide grooves 33. The locking function of the guide grooves 33 for locking the back lid 25 will be described in a later stage. As earlier noted, the lower end portion of the back lid 25 is urged to approach the front lid 13. The initial guide portions 34 of the guide grooves 33 extend substantially along a rotational loci of the guided pins 30 when the back lid 25 is in the lid closed condition. When the front lid 13 is in the lid closed position, as shown in Fig. 1A, the guided pins 30 come in resilient contact with substantially horizontal inner bottom surfaces 34a of the initial guide portions 34 and their front side surfaces 34b, which are substantially vertical to the inner bottom surfaces 34a, thereby preventing the back lid 25 from being excessively rotated in the above-mentioned direction. The position of the back lid 25 in this state is the lid closed position. Under this condition, the back lid's main portion 26 opposes the front surface of the front wall portion 14 across the magnetic tape 7, so that the two lids are in a substantially parallel relationship. Also, the front end face of the rectangular cover portion 28 is located slightly below the lower edge of the magnetic tape 7 and comes in slight contact with, or approaches very close to, the rear surface of the front surface portion 14 of the front lid 13. Therefore, in the lid closed state, the front and top of the magnetic tape 7 are covered by the front lid 13. Also, the back and bottom of the magnetic tape 7 are covered by the back lid 25. In the lid closed state, the back lid 25 is inhibited from moving toward the lid opened position. That is, the back lid 25 is locked in the lid closed position. Therefore, since the lids are substantially locked together, the front lid 13 is also locked in the lid closed position. The above-mentioned locking operations are affected by the initial guide portions 34 of the guide grooves 33 and the spring forces of the springs 32. More specifically, in Fig. 1A, a straight line L₁ represents an extension line of the upper surfaces 34c (these upper surfaces 34c will be referred to hereinafter as "locking surfaces") of the initial guide portions 34 of the guide grooves 33. A curve R represents a rotational locus of the outer peripheral surfaces of the guided pins 30 at their portions which contact the locking surfaces 34c when the back lid 25 is in the lid closed condition. Further, a straight line ℓ connects the centers of the guided pin 30 and the support pin 27. A straight line L₂ is tangent to the rotational locus R at the point where the straight lines ℓ and the rotational locus R cross each other. The locking surfaces 34c are formed so as to extend in the direction slightly inclined to the rearward relative to line L₂. In Fig. 1A, the locking surfaces 34c are shown to be inclined by approximately 5 degrees relative to line L₂. Accordingly, when force is applied to the front lid 13 urging it to open, such force is also applied to the back lid 25. Since the back lid 25 is urged to rotate by the springs 32, the guided pins 30 are urged to rotate in the lid opening direction by the force which is always urged against the locking surfaces 34c in substantially the same direction as the direction defined by the straight line ℓ. Then, since the locking surfaces 34c have the inclined angles described above, the guided pins 30 are urged against the locking surfaces 34c, so that the guided pins 30 are inhibited from moving in any direction. Thus, the back lid 25 is inhibited from being moved in the lid opening direction, whereby the front lid 13 is also inhibited from moving in the lid opening direction. Therefore, the back lid 25 and the front lid 13 are both locked in their lid closed positions. The front lid 13 is locked by its two support members 23 which are coupled to the back lid 25. The front lid support members 23 are located toward the center from the left and right ends so that, even when the front lid 13 is pushed toward the lid opening direction from the lid closed condition, the front lid 13 is hardly twisted thereby. Accordingly, there is no substantial risk that one portion of the front lid 13 will be displaced in the lid opening direction causing the magnetic tape 7 to be exposed or the front lid 13 to be deformed. For example, when the dimension of the front lid 13 is relatively small in the left to right direction, the back lid 25 may be locked at one place, if necessary. In other words, the locking surface 34c may be formed only in one initial guide portion 34 of the two guide grooves 33. According to this modification, the position at which the back lid's locking force acts on the front lid 13, is located substantially toward a central position relative to the side end portions of the front lid 13, increasing the front lid's mechanical strength against twisting. It is sufficient that one of the springs 32 urges the back lid 25 to rotate. Further, this spring 25 may be unitarily formed with the back lid 25. The front lid 13 and the back lid 25 are moved in the lid opening direction by a lid opening device provided in a recording and/or reproducing apparatus (not shown) when the tape cassette 1 is loaded into the recording and/or reproducing apparatus. More specifically, the recesses 14b are formed on the lower end portion of the front surface portion 14 of the front lid 13 at positions corresponding to the bosses 31 of the back lid 25 in the lid closed position. Therefore, when the tape cassette 1 is inserted into a cassette insertion portion (not shown) of the recording and/or reproducing apparatus, lock releasing portions of the lid opening means (not shown) are inserted through the recesses 14b into the tape withdrawing recess portion 9, urging the bosses 31 to move rearward. This causes the back lid 25 to rotate counter-clockwise and the front portion of the back lid 25 to incline in the forward direction as shown in Fig. 1B. Thus, the guided pins 30 move to the positions where the initial guide portions 34 meet the intermediate portions 35 of the guide grooves 33. Then, a lid opening force is applied to the front lid 13, whereby the front lid 13 rotates in the lid opening direction. In accordance with this rotation of the front lid 13, the two support members 23 rotate around the coaxial support pins 27 of the back lid 25. The guided pins 30 move through the intermediate portions 35 and the final guide portions 36 of the guide grooves 33 in the lid opening direction, ultimately reaching the lid opening position shown in Fig. 1C. As the guide pins 30 are guided by the intermediate portions 35 of the guide grooves 33, the inclination of the back lid 25 relative to the font surface portion 14 of the front lid 13 is gradually increased. In contrast, as the guide pins 30 are guided by the final guide portions 36 of the guide grooves 33, the above-mentioned inclination is gradually decreased. When the back lid 25 reaches the lid opening position, the back lid 25 becomes substantially parallel to the front lid 13. The front lid 13 and the back lid 25 are moved in the lid closing direction oppositely from the above-mentioned movement in the lid opening direction. Since most portions of the back lid 25, except its upper end portion, are significantly spaced from the magnetic tape 7 before opening the lid, even if the back lid 25 has static electricity, there is no risk that the magnetic tape 7 will be attracted by the back lid 25 and moved therewith. Further, the lower end portion 14c of the front lid 13, between the recesses 14b, is curved in such a manner as to be displaced rearward in the lower end thereof. A rotational locus r₁ (see Fig. 1A) of the place most distant from the rotation axis of the central portion of the front lid 13 is displaced rearward by a distance a as compared with a rotational locus r₂ provided when the lower end portion 14c is not curved. Thus, the cassette loading position of the recording and/or reproducing apparatus (not shown) can be approached by a head drum (not shown) of the recording and/or reproducing apparatus by the distance a , thereby allowing the mechanical deck to be compact in size. In this embodiment of the present invention, the spring for urging the back lid to rotate and one portion of the guide groove for defining the movement locus of the back lid are utilized to lock the back lid in the lid closed position. Therefore, a special locking device is not needed, which simplifies the tape cassette structure.

Claims: A tape cassette (1) having a cassette casing (2) and a tape (7) in use of which cassette (1) the tape (7) is to be withdrawn to the outside of the cassette casing (2) such that a tape run having front and rear sides extends along a tape withdrawing area between tape exit portions (8,8′) formed at two end portions of a front wall (2a) of the cassette casing (2), and including a front lid (13) rotatably attached to the cassette casing (2) so as to cover the whole area of the front wall (2a) of the cassette casing (2), a back lid (25) rotatably attached to the front lid (13) so as to substantially cover the rear side of the tape run, the front and back lids (13,25) being mounted in the cassette (1) for movement between an open position allowing access to the tape run when the cassette (1) is in use, and a closed position wherein the front and rear sides of the tape run are substantially covered by the front and back lids (13,25) when the tape cassette (1) is not in use, and locking means for locking the back lid (25) in the closed position when the tape cassette is not in use, characterised in that the locking means comprise at least one guide pin (30) formed on the back lid (25), the cassette casing (2) including a corresponding guide groove (33) for receiving the guide pin (30), a lower end (34) of the guide groove including an over-centre locking surface (34c) whereby the guide pin (30) is locked. A tape cassette according to claim 1, wherein the back lid (25) includes a second similarly locked guide pin (30). A tape cassette according to claim 1 or 2, further comprising spring-biasing means (32) for urging the back lid (25) toward the closed position. A tape cassette according to any one of the preceding claims, wherein the cassette casing (2) includes a recess (14b) for receiving the lock releasing device of a tape cassette recorder/player, and the back lid (25) includes one or more lock releasing bosses (31) along one edge thereof for engagement with the lock releasing device, and wherein the locking means includes means connected to the back lid (25) for unlocking it when the lock releasing bosses (31) are engaged by the lock releasing device.

Inventors: FUJII HIROSHI, FUJII, HIROSHI
Applicants: SONY CORP, SONY CORPORATION
Application year: 1990
Main classification: G11B23
IPC codes: G11B23