Disk cartridge

Abstract: A disk cartridge has a case comprising an upper and a lower shell halves (6, 7) for accommodating a disk. The case has a spindle insertion hole (8), a head insertion hole (9) and a shutter (10) for opening and closing the two holes (8, 9). The case has at least one of a disconnection preventing mechanism (25, 35; 39, 40) for preventing an elastic spring (23) for urging the shutter (10) from being disconnected from a slider (14) and a part of the case, a drive pin smooth motion mechanism (42) for moving a drive pin (P1, P2) on the slider (14), a shutter locking mechanism (56, 60) for locking the shutter (10) at a closing position, a disk center holding mechanism (85, 101, etc.) for supporting the disk at its center position, a disk periphery holding mechanism (18a, 19a) for holding the periphery of the disk, a writing protection mechanism (29a, 29b) for prevention new information from being recorded on the disk and a mechanism (417) for forming the case with a good outer appearance.

Description: BACKGROUND OF THE INVENTION The present invention relates to a disk cartridge for encasing a recording medium such as an optical disk or a magnetic disk. In general, a magnetic disk or an optical disk is encased in a cassette case made of two shell halves. A hole into which a spindle for rotating the disk to be inserted is formed in the center portion of the cassette case. Adjacent to the spindle hole, a head insertion hole into which a writing/reading head is to be inserted is formed in the radial direction to traverse the recording surface of the disk. The head insertion hole is opened and closed by a shutter slidingly provided on the cassette case. The front end of the cassette case has a guide portion along which is reciprocatingly moved a slider to hold the shutter for opening and closing the head insertion hole and the spindle insertion hole. The slider is of a rectangular bar-shape and holds the bent portion of the shutter. The shutter has a pair of side plate portions extending parallel to each other from the opposite sides of the bent portion thereof in order to open and close the above two holes of the cassette case. There is provided a twist spring coil between the front portion of the slider and the cassette case for urging the shutter in the direction where the two holes are closed. As mentioned above, the opposite ends of the twist coil springs are held at the front end of the slider and at the front corner of the cassette case, respectively. Such a disk cartridge according to the precharacterizing parts of claims 1 and 2 is disclosed in EP-A-0271997 in which shutters are supported by a slider. One end of a wire torsion spring is connected to the one end of the slider through a simple hole and the other end of the spring hole is connected to the corner portion of a shell through a simple hole as shown in Figure 4. Further, a pair of bias spring members for biasing the sliding shutter is disclosed in EP-A-0266781 in which one bent end of the spring member is held by a cut-out and a rib provided on the case as a spring receiving means. In the above EP-A-0 271 997, there is not a preventing means for preventing the bent ends of the spring from being taken off from the spring receiving portions at the one end of the slider and in the corner portion of the case. Further, in the above EP-A-0 266 781, the one bent end of the spring is not held directly in the strip. Therefore, the bent end thereof may be taken off from the space between the end wall lid of the case and the strip as shown in Figure 4 when it is dropped. If the ends of the spring means come off from their respective spring receiving portions when the cartridge is dropped, the shutter is opened, so that dust may enter the case. Both EP-A-0 271 997 and EP-A-0 266 781 do not disclose means for maintaining the shutter at its closing position for closing the spindle and head insertion holes provided on the shells. SUMMMARY OF THE INVENTION It is the object of the invention to provide a disk cartridge in which a spring for urging a slider for supporting the shutter does not easily come off from the slider and the corner of a case, and the shutter can be maintained at its closing position even when an impact force is exerted thereon, e.g. the disk cartridge is dropped. According to one aspect of the invention, there is provided a disk cartridge with a shutter which is slidably mounted on a case and urged by an elastic spring in a direction where an opening portion formed in the case is closed in order to open and close the opening portion thereof, wherein the shutter is mounted onto the case, through a slider which is slidably accomodated at the front portion of the case, the slider having one end with an insertion hole for receiving a bent end provided at an end of an arm of the elastic spring, characterized in that the insertion hole is bent to form a hook hole in a hook-shape in longitudinal direction of the slider and provided, at an inlet thereof, with a sharp projection extending inwardly thereof for holding the bent end of the elastic spring and a cut away path communicating with a bent hole and extended in a longitudinal direction of the slider to the guide arm, the inlet of the insertion hole having a width for permitting the bent end to pass therethrough. In this aspect, the bent end of the spring can be easily inserted into the hole of the slider and does not come off from the insertion hole even when the cartridge is dropped. According to a further aspect of the invention, there is provided a disk cartridge with a shutter which is slidably mounted on a case and urged by an elastic spring in a direction where an opening portion formed in the case is closed in order to open and close the opening portion thereof, wherein the shutter is mounted onto the case through a slider which is slidably accommodated at the front portion of the case, the slider having one end with an insertion hole for receiving a bent end provided at an end of an arm of the elastic spring, characterized in that the insertion hole has a closed space for holding therein the bent end thereof extending in widthwise direction of the slider and a cut away path extended in longitudinal direction of the slider to communicate with the closed space to guide the arm of the spring, the bent end being inserted into the closed space through the cut away path while being turned. In this aspect the bent end of the spring does not come off from the insertion hole when when the cartridge is dropped. Further objects, features and other aspects of this invention will be understood from the following detailed description of the preferred embodiments of this invention with reference to the drawings. BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings: FIG. 1 is a perspective view of a disk cartridge according to this invention; FIG. 2 is a partial perspective view of the disk cartridge when a shutter is opened; FIG. 3 is an exploded perspective view of the shutter and a slider; FIG. 4 is a perspective view of a guide portion of the disk cartridge; FIGS. 5 and 6 are two operational views showing a function of a twist coil spring when the shutter is opened and closed; FIG. 7 is a longitudinally sectional view of a front portion of the slider; FIG. 8 is a cross sectional view taken along the line VIII - VIII; FIG. 9 is a front view of the slider; FIG. 10 is a perspective view of the front portion of the slider; FIG. 11 is a longitudinally sectional view of a front portion of a slider, showing another embodiment with respect to a connecting portion of the slider and the twist coil spring; FIG. 12 is a cross sectional view taken along the line XII - XII; FIG. 13 is a perspective view of the slider shown in FIG. 11; FIG. 14 is a front view of the slider shown in FIG. 11; DETAILED DESCRIPTION OF THE INVENTION First Embodiment As shown in FIGS. 1 and 2, a disk cartridge C for encasing an optical disk, has an upper and a lower shell halves 6, 7 which are assembled in alignment with each other to form a case. The center portion of the case has a spindle insertion hole 8 and a head insertion hole 9 disposed adjacent to the spindle insertion hole 8 to receive a reading/writing head (not shown) to form an opening portion of the case. In order to open and close the opening portion, a shutter 10 is provided slidably in the left and right directions on the disk cartridge C. The shutter 10 is, as shown in FIG. 3, so formed that a stainless plate is bent at its center (top plate 12) to form two closing plates 11, 11 opposite to each other. Each closing plate has a slide plate 13 at its lower end. The slide plate 13 is slidably guided by a retaining plate 30 attached to the surface of each shell half. The top plate 12 is held by an elongated slider 14 through two screws 15, 15 each of which is passed through an opening 16 to be inserted into a receiving hole 17 provided in the slider 14. The rear portion of the top plate 12 (right portion as viewed in FIG. 3) has an opening 18 in registration with a receiving recess 19 provided at the rear portion of the slider when the slider 14 and the top plate 12 are combined together. The recess 19 receives a drive pin P1 (FIG. 4) provided in a reading/writing device (player) (not shown) to open and close the shutter 14 when the disk cartridge C is charged into the player. Each receiving hole 17 of the slider 14 is opposed to an opening of the top plate 12. On the opposite side faces of the slider 14 are provided a pair of guide grooves 20, 20 which engage with two guide rails 21, 21 in a guide portion formed on the front end of the disk cartridge on the side of the player. The slider 14 has a slanted surface 22 at its front end, as shown in FIG. 4, so that a drive pin P2 disposed opposite to the drive pin P1 can slide smoothly on the front portion of the slider 14. That is, when the disk cartridge C is charged into the player, one of the drive pins P1, P2 (pin P1 in FIG. 4) is received in the receiving recess 19 of the slider 14 through the opening 18 of the top plate 12. Then, the pin P1 is moved in the left direction as viewed in FIG. 4 to open the spindle insertion hole 8 and the head insertion hole 9. At that time, the other drive pin P2 rides on the slanted surface 22 to be moved in the right direction. As a result, the two pins P1, P2 are moved in the opposite directions and passed by each other. Thus, the slanted surface 22 of the slider 14 permits the pin P2 to slide smoothly on the slider 14. In this case, the pin P2 which does not function to open and close the opening portion of the case is called a useless pin. In contrast, when the disk cartridge C is turned over to be charged into the player, the pin P2 functions to open and close the opening portion thereof while the pin P1 is called a useless pin. As shown in FIGS. 1, 5 and 6, on the right side of the front end of the disk cartridge is accommodated a twist coil spring 23 which is provided between the front corner of the disk cartridge C and the front portion of the slider 14 to urge the shutter 10 toward the direction where the opening portion of the disk cartridge is closed. The front end of the slider 14 is in the form of a pent roof and has a recess 24 at its lower side as shown in FIGS. 7 and 10. At the base portion of the front end thereof is provided an insertion hole 25 adjacent to the recess 24 for receiving a bent end 23a of the coil spring 23. The insertion hole 25 has a substantially rectangular shape in its cross section, which can pass the bent end 23a and a substantial V-shape (hook-shape) as a whole in its longitudinal direction to form a hook hole 25b which has a projecting portion 28 at its turning point. That is, the insertion hole 25 has a downslope part slanting downwardly from an inlet 25a at the right end of the recess 24 and an upslope part slanting upwardly from the lower end of the downslope part. At the lower position of the inlet 25a of the downslope part thereof is provided a sharp projection 26 which projects inwardly of the insertion hole 25 to form a space 26a for holding the bent end 23a of the spring 23. There is provided a cut away path 27 which extends in the longitudinal direction of the slider 14 to communicate with the hook hole 25b. When the bent portion 23a of the coil spring 23 is inserted, into into the insertion hole 25, the bent portion 23a is passed through the inlet 25a in a state wherein the bent portion 23a is extended horizontally in the widthwise direction of the slider 14 and wherein an arm 32 of the coil spring 23 is extended vertically to be accommodated in the path 27. The bent portion 23a can be thus inserted smoothly deeply into the insertion hole 25. When the shutter 10 is in a closing state, the bent portion 23a is held in the space 26a by the sharp projection 26 projecting in the longitudinal direction of the slider 14. The coil spring 23 is expanded and shrunken, as shown in FIGS. 5 and 6, in response to the reciprocal movement of the shutter 10. The bent portion 23a of the spring 23 is accommodated deeply in the upslope space of the hook hole 25b when the shutter 10 opens the opening portion of the disk cartridge C in a state wherein the coil spring is shrunken as shown in FIG. 6. In contrast, as mentioned above, the bent portion 23a is held by the sharp projection 26 in the space 26a as shown in FIG. 7, when the opening portion is closed by the shutter 10. In this manner, the bent portion 23a is reliably held in the insertion hole during the reciprocal movement of the shutter 10. In FIGS. 1 and 2, a reference numeral 29 indicates a writing protection part for preventing new information from being recorded on the recording surface of the disk. As mentioned above, the insertion hole 25 is bent in a V-shape to form the projecting portion 28 at the turning position of the hook 25b and the sharp projection 26 projecting toward the inside of the insertion hole 25. Therefore, when the bent end of the coil spring 23 is once inserted in the insertion hole 25, it is not easily disconnected from the insertion hole 25 even if the coil spring 23 is moved abruptly and an impact force is exerted on the disk cartridge when it is dropped on a floor. Further, the sharp projection 26 located near the inlet 25a of the insertion hole 25 has an upper face to guide the bent end 23a of the coil spring 23 toward inside of the insertion hole 25 when the bent end 23a is accommodated in the insertion hole 25. Therefore, an assembling operation of the coil spring 23 and the shutter 10 is performed easily and speedily. Second Embodiment The connecting portion between the bent end 23a of the coil spring 23 and the front end of the slider 14 may be constructed as shown in FIGS. 11 to 14. That is, the front end of the slider 14 has a pent roof-shape provided with a recess 34 at its lower face, and the base portion of the pent roof-shape is provided with an insertion hole 35 having a closed space 35c for accommodating the bent end 23a of the coil spring 23. The insertion hole 35 is in the shape of a rectangular parallelepiped, and has, as shown in FIG. 11, a length for receiving' the bent end 23a thereof in the longitudinal direction of the slider 14. At the front end walls 35a, 35b in which the closed hole 35C is formed is provided a cut away path 37 for introduction of the bent end 23 thereof and for swinging motion of the arm 32 thereof during the opening and closing motion of the shutter 10. The width of the path is determined slightly larger than that of the arm 32 of the coil spring 23. When the bent end 23a thereof is accommodated into the insertion hole 35, the bent end 23a is extended along the bottom opening of the cut away path 37 to be inserted into the right end space of insertion hole 35 as viewed in FIG. 13, and the bent end 23a is then turned by about 90 degrees in the direction indicated by an arrow E. The coil spring 23 is expanded and shrunken with the bent end 23a thereof directed in the widthwise direction of the slider 14. Further, the arm 32 thereof is swung along two opposite walls defining the cut away path 37. Therefore, the bent end 23a thereof is always held in the insertion hole 35 so as not to be disconnected therefrom. The bent end 23a thereof can be also inserted into the insertion hole 35 in the longitudinal direction (arrow F) of the slider 14 through the inlet of the cut away path 37 in the wall 35a extended vertically as viewed in FIG. 11. The above structure of the connecting portion between the bent end 23a thereof and the front end of the slider 14 permits the bent end 23a to be reliably held in the insertion hole 35 even if the coil spring is moved abruptly and the disk cartridge is dropped to be subjected to an impact force.

Claims: A disk cartridge (C) with a shutter (10) which is slidably mounted on a case (6,7) and urged by an elastic spring (23) in a direction where an opening portion (8,9) formed in the case (6,7) is closed in order to open and close the opening portion thereof, wherein the shutter (10) is mounted onto the case (6,7) through a slider (14) which is slidably accommodated at the front portion of the case (6,7), the slider (14) having one end with an insertion hole (25) for receiving a bent end (23a) provided at the end of an arm (32) of the elastic spring (23), characterized in that the insertion hole (25) is bent to form a hook hole (25b) in a hook-shape in longitudinal direction of the slider (14) and provided, at an inlet (25a) thereof, with a sharp projection (26) extending inwardly thereof for holding the bent end (23a) of the elastic spring (23) and a cut away path (27) communicating with the hook hole (25b) and extended in longitudinal direction of the slider (14) to the guide arm (32), the inlet (25a) of the insertion hole (25) having a width for permitting the bent end (23a) to pass therethrough. A disk cartridge (C) with a shutter (10) which is slidably mounted on a case (6,7) and urged by an elastic spring (23) in a direction where an opening portion (8,9) formed in the case (6,7) is closed in order to open and close the opening portion thereof, wherein the shutter (10) is mounted onto the case (6,7) through a slider (14) which is slidably accommodated at the front portion of the case (6,7), the slider (14) having one end with an insertion hole (35) for receiving a bent end (23a) provided at an end of an arm (32) of the elastic spring (23), characterized in that the insertion hole (35) has a closed space (35c) for holding therein the bent end (23a) of the arm of the elastic spring extending in widthwise direction of the slider (14) and a cut away path (27) extended in longitudinal direction of the slider (14) to communicate with the closed space to guide the arm (32) of the spring, the bent end (23a) being inserted into the closed space through the cut away path (27) while being turned. A disk cartridge (C) according to claim 1, wherein the insertion hole (25) has a downslope part slanting downwardly for the inlet of the insertion hole (25) and an upslope part slanting upwardly from the lower end of the downslope part, a projecting portion (28) being formed at turning point of the hook hole (25b). A disk cartridge (C) according to claim 1 or 2, wherein the one end of the slider (14) has a pent-roof shape to form a recess (24, 34) on its lower side, the insertion hole (25, 35) being provided at a base portion of the pent-roof shape. A disk cartridge (C) according to anyone of the preceding claims 1 to 4, wherein a curved surface (42) is provided at a corner of a rear end of the slider (14) in a direction where the shutter (10) opens the opening portion of the case, a rear end of the shutter (10), corresponding to the rear end of the slider (14), being cut away to form a cut portion (43) from which the curved surface (42) is projected outwardly.

Inventors: AKIYAMA NOBORU, KAMEDA KATSUMI, AKIYAMA, NOBORU, KAMEDA, KATSUMI, AKIYAMA, NOBORU, C/O DAI NIPPON INSATSU K.K., KAMEDA, KATSUMI, C/O DAI NIPPON INSATSU K.K.
Applicants: DAINIPPON PRINTING CO LTD, DAI NIPPON INSATSU KABUSHIKI KAISHA
Application year: 1991
Main classification: G11B23
IPC codes: G11B23, B29C45