Disk cartridge

Abstract: A disk cartridge comprises a shutter which is slidably mounted on a case. The shutter is urged by an elastic spring (23). The case has a pair of hook members (535,536) which are provided near or at a part of a peripheral side wall of the case. A pair of hooks (39,40) are provided at distal ends of said hooks members in such a manner that an insertion inlet for the bent end (23a) is formed. The pair of hooks (39,40) are opposed to each other so that the insertion inlet is opened in a slanted direction with respect to widthwise direction of the case.

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 is 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 in 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 coil spring 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 spring are held at the front end of the slider and at the front corner of the cassette case, respectively. However, if the disk cartridge is subjected to an impact force, e.g., when it is dropped on a floor, the twist coil spring may be disconnected from the front end of the slider and the corner of the cassette case. Further, an operation for connecting the coil spring to the slider and the cassette case is troublesome, and dust may enter the cassette case when the case is dropped to move the shutter to open the two holes of the cassette case. A reading/writing device (player) for receiving the disk cartridge has a pair of drive pins for opening and closing the shutter, and, however, neither a relational movement between the drive pins and the shutter nor a charging movement of the disk cartridge into the reading/writing device is smooth. The disk is held, at its center portion, by the spindle in a floating condition in the cassette case, and, however, the disk cannot be held stably therein. Moreover, when the disk is rotationally held, the information recording surface of the disk sometimes abuts against the inner surface of the case to cause a scratch and a damage thereonto. When the disk happens to strongly abut against the edge of the head insertion hole, the information recording surface of the disk may suffer a damage. When the peripheral edge of the disk in the case strikes against the corner of a substantially circular surrounding wall, the peripheral edge thereof may suffer a damage. In addition, there is provided a writing protection mechanism in the case for preventing old information having been already recorded on the disk from being erased by recording new information onto the disk. However, there may occur a case that some parts of the writing protection mechanism are assembled upside down in the case. EP-A-0 339 651 according to the precharacterizing part of claim 1 discloses a disk cartridge including a shutter slidably mounted on a case. Said shutter is urged by an plastic spring in order to close an opening portion formed in the case. A bent end is formed at an end of an arm of the elastic spring which is received by a spring receiving portion of the case. SUMMARY OF THE INVENTION It is an object of this invention to provide a disk cartridge in which a spring for urging a shutter does not easily come off from the shutter and a corner of a case and can be easily assembled in the case. This object is solved by the features of claim 1. Further embodiments are claimed in the sub-claims. 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 a longitudinally sectional view of a front portion of the slider; FIG. 4 is a cross sectional view taken along the line IV-IV in Fig. 3; FIG. 5 is a front view of the slider; FIG. 6 is a perspective view of the front portion of the slider; FIG. 7 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. 8 is a cross sectional view taken along the line VIII-VIII in Fig. 7; FIG. 9 is a perspective view of the slider shown in FIG. 7; FIG. 10 is a front view of the slider shown in FIG. 7; FIG. 11 is a perspective view of a connecting portion of the twist coil spring and a lower shell half of the disk cartridge; FIG. 12 is an explanatory view showing a function of the connecting portion shown in FIG. 11; FIG. 13 is a perspective view of the twist coil spring; FIGS. 14 and 15 are two explanatory views showing a function of the connecting portion shown in FIG. 11 when the shutter is opened and closed. 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. As shown in FIG. 1, 14 and 15, 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. 3 and 6. 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 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. 14 and 15, 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. 15. In contrast, as mentioned above, the bent portion 23a is held by the sharp projection 26 in the space 26a as shown in FIG. 3, 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. 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. 7 to 10. 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. 7, 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. 9, 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. 7. 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. The twist coil spring 23 is, as shown in FIG. 13, made of an elastic wire, and has a center coil portion 31 and two arms 32, 33 extended to the opposite sides of the center coil portion 31. The ends of the arms 32, 33 are bent perpendicularly to those arms 32, 33 to form two bent ends 23a, 23b, respectively. As shown in FIGS. 11 and 12, the lower shell half 7 of the disk cartridge C has, at its front corner, a pair of hook members 535, 536 extending parallel to each other in the longitudinal direction of the shell half 7 and formed at the end portions of the guide rails 21, 21. At the respective ends of the hook members 535, 536 are, as shown in FIG. 16, provided a pair of hooks 39, 40 opposed to each other, which form cooperatively an insertion inlet 38 open in the slanted direction B with respect to the widthwise direction A. The two hooks 39, 40 have two sharp projections 39a, 40a projected inwardly in a space 41 defined by the hook members 535, 536, respectively. The bent end 23b of the coil spring 23 is kept in the space 41. When the coil spring 23 is expanded and shrunken as shown in FIGS. 14 and 15, the bent end 23b thereof is moved between a position 23b 1 indicated by a solid line and either a position 23b 2 or a position 23b 3 . However, since the insertion inlet 38 is open to the slanted direction B with respect to the widthwise direction of the case, the bent end 23b is never disconnected from the space 41 after it is once accommodated therein. When the disk cartridge C is assembled, the bent end 23b is inserted into the space 41 in the slanting direction B as shown by a position 23b 4 of a dotted line. The above structure makes it possible to reliably hold the bent end 23b in the space 41, and the bent end 23b can be easily and speedily inserted when the disk cartridge is assembled.

Claims: A disk cartridge 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 (8,9) thereof, a bent end (23b) being formed at an end of an arm (33) of the elastic spring (23), wherein the case (6,7) includes a spring receiving portion which is provided near or at a part of the peripheral side wall of the case (6,7) so as to be expanded parallel to each other in a direction where the elastic spring (23) is expanded and contracted, characterised in that said spring receiving portion comprises a pair of hook members (535,536), having a pair of hooks (39,40) being provided at distal ends thereof, respectively, to form an insertion inlet (38) for said bent end (23b) which is held in a space (41) defined by the hook members (535,536), the pair of hooks (39,40) being opposed to each other so that the insertion inlet (38) is open in a slanted direction with respect to widthwise direction of the case (6,7). A disk cartridge according to claim 1, wherein each of hooks (535,536) has a sharp projection (39a,49a) projected inwardly in the space defined by the hook members (535,536). A disk cartridge according to claim 2, wherein an inner hook member (536) which is located in an inner position of the cartridge is longer than an outer hook member (535) which is located in an outer position of the cartridge so as to form the insertion inlet (38) directed upwardly and slantedly (see Figure 15). A disk cartridge according to one of claims 1 to 3 wherein the shutter (10) is mounted onto the case (6,7) through a slider (14) which is slidable accommodated at the front portion of the case (6,7) the slider (14) having one end with an insertion hole (25) for receiving the other bent end (23a) provided at an end of an arm (32) of the elastic spring (23), 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 other bend end (23a) of the elastic spring (23a) and a cut away path (27) communicating with a bent hole (25a) and extended in longitudinal direction of the slider (14) to the guide arm (32), the inlet (25a) of the insertion hold (25) having a width for permitting the bend end (23a) to pass therethrough. A disk cartridge according to claim 4, wherein the insertion hole (25) has a downslope part slanting downwardly from 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 (256). A disk cartridge according to one of claims 1 to 5, wherein each of hooks (39,40) has a sharp projection (39a,40a) projected inwardly in the space defined by the hook members (535,536). A disk cartridge according to one of claims 1 to 6, wherein an inner hook member (536) which is located in an inner position of the cartridge is longer than an outer hook member (535) which is located in an outer position of the cartridge so as to form the insertion inlet (38) directed upwardly and slantedly.

Inventors: AKIYAMA NOBORU, KAMEDA KATSUMI, AKIYAMA, NOBORU, KAMEDA, KATSUMI, Akiyama, Noboru, Dai Nippon Insatsu K.K., Kameda, Katsumi, 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