Disk cartridge

Abstract: A disk cartridge has a shutter (10) connected to a slider (14). The slider (14) has a receiving recess (19) for receiving a drive pin provided in a read/writing device. The shutter locking mechanism comprises a stopping hole (53) provided adjacent to the receiving recess (19). A stopper (59) has a head (60) supported on a leg portion. The head (60) passes through the stopping hole (53) to project partially into the receiving recess when the shutter is in a closed state. The stopper (59) has a stopping piece (64) for cooperating with a stopping projection (55) provided at a head end of the slider. A room (56) is provided at a position in the case corresponding to the stopping hole for accommodating a leg portion (61) of the stopper. An elastic member (160) is accommodated in the room (56) to urge the stopper (59) toward the slider (14).

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-0 218 231 according to the preamble of claim 1 discloses a disk cartridge with a shutter for opening and closing an opening portion of a case of the cartridge. The shutter is connected to a slider movable on a guide portion of the case. The slider has an opening for receiving a shutter moving lever for moving the shutter together with a slider. This opening corresponds to an opening of the shutter. The case includes a shutter locking mechanism for locking the shutter at its closed position. The shutter locking mechanism includes a stopper having a projection which projects into the opening the slider. The stopper has a u-shaped form wherein one leg having the projection is flexible. When the shutter moving lever enters the opening the projection will be moved out of the opening and the shutter can be moved into the opening direction. SUMMARY OF THE INVENTION It is the object of this invention to provide a disk cartridge in which the shutter is prevented from opening even when an impact force is imparted to the disk cartridge. 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 part of the disk cartridge, showing a shutter locking mechanism; FIG. 4 is an exploded perspective view showing a state of engagement of the slider and a stopper for the shutter locking mechanism; FIG. 5 is a plan view of a rear portion of the slider; FIG. 6 is a side view of the rear portion of the slider; FIG. 7 is a cross sectional view taken along the line VII - VII in Fig. 6; FIG. 8 is a longitudinally sectional view taken along the line VIII-VIII in Fig. 5; FIG. 9 is a plan view of the stopper for the shutter locking mechanism; FIG. 10 is a side view of the stopper; FIG. 11 is a cross sectional view taken along the line XI-XI in Fig. 10; and FIG. 12 is a bottom view of the stopper. DETAILED DESCRIPTION OF THE INVENTION 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. 4, 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 shutter 10 is kept in a closing state by an urged force of the coil spring 23 and, however, the following shutter locking mechanism may be, as shown in FIGS. 3 to 12, provided for safe. That is, the slider 14 has, on the bottom side of the rear portion thereof, a cut away portion 52 as shown in FIGS. 4 and 6 to 8. The cut away portion 52 extends from the rear end of the slider 14 to a portion slightly over the receiving recess 19 in the longitudinal direction of the slider 14 in a state wherein the left side of the rear portion of the slider 14, as viewed in FIG. 8, is cut away so as to form a stopping hole 53 open to the receiving recess 19. The stopping hole 53 extends to the upper surface of the slider 14 and has a length larger than that of the receiving recess 19 in the longitudinal direction of the slider 14. Further, the stopping hole 53 has, at its front and rear ends, a slanted ceiling wall 54 and a stopping piece 55, respectively. The disk cartridge C has a small room 56 at a position corresponding to the stopping hole 53 of the slider 14 when the shutter 10 is in a closing state. The room 56 comprises, as shown in FIG. 3, two guide walls 57, 57 extended in the longitudinal direction of the case and a part of the surrounding wall 58 surrounding the periphery of the disk. The room 56 has, therein, a stopper 59 and an elastic member 160 urging the stopper 59 upwardly. The stopper 59 comprises, as shown in FIGS. 9 to 11, a plate-like head 60, two open legs 61, 61 and a projection 62 extended downwardly between the two open legs 61. The head 60 passes vertically through the stopping hole 53 and the cut away portion 52 to be projected into the receiving recess 19 of the slider 14, and has a slanted wall 63 and a stopping projection 64 on the front and rear sides on the top face thereof, respectively. The slanted wall 63 contacts the slanted ceiling wall 54 of the stopping hole 53 while the stopping projection 64 contacts the stopping piece 55. The elastic member 160 is a compressed coil spring which is provided between the projection 62 of the stopper 59 and a receiving space 65 at the bottom of the room 56 in order to urge the stopping member 59 toward the slider 14. Next, the operation of the shutter locking mechanism will be explained with reference to the opening and closing movement of the shutter 10. When the disk cartridge C is located outside of the player, that is, the disk cartridge C is not used, the shutter 10 is in a closing state wherein the opening portion of the case is closed by the function of the coil spring 23. At this time, the stopper 59 is, as shown in FIG. 3, pushed upwardly by the elastic member 160 toward the front end of the case in a state wherein the head 60 of the stopper 59 is accommodated in the stopping hole 53. Therefore, the slider 14 is fixed at a position where the shutter 10 is in a closing state, so that the shutter 10 is kept at its closing position. Even if an external force is exerted on the slider 14, the slider 14 is fixed at its closing position by the engagement of the stopping piece 64 of the stopper 59 with the stopping piece 55 of the slider 14. The stopper 59 is urged vertically by the spring 160 as viewed in FIG. 3. and, however, a shoulder Sh of the stopper 59 engages with a wall of the case. Therefore, even when the slider 14 is moved in its opening position, the stopper 59 is not pushed out of the room 56 by the spring 160. When the disk cartridge C is charged into the player, the drive pin P1 is inserted into the receiving recess 19 thereby to press downwardly the head 60 of the stopper 59 against the spring force of the elastic member 160, resulting in that the stopper 59 is stopped at the lower portion of the cut away portion 52. At this time, the open legs 61, 61 are guided along the guide walls 57. With this state, the stopping piece 64 is released from the stopping piece 55 to enable the slider 14 to be moved in its opening direction (in the left direction as viewed in FIG. 3). In this manner, in a state wherein the drive pin P1 engages with the receiving recess 19, the slider 14 can be moved in the opening direction of the shutter 10 so as to be slid along a guide portion of the case to open the opening portion of the case. Thereafter, when the drive pin P1 comes off from the receiving recess 19, the slider 14 can be moved in the closing direction of the shutter 10. The rear end face of the cut away portion 52 abuts against the slanted wall 63 of the stopper 59 shortly before the shutter is completely closed thereby to press slightly the stopper 59 into the room 56. When the slider 14 is moved to a position where the stopping hole 53 is opposed to the head 60 of the stopper 59, the head 60 is pushed upwardly into the stopping hole 53. Thus, the shutter 10 is again in a locked state. The above locking structure can prevent the shutter 10 from opening even when an impact force is imparted to the disk cartridge C.

Claims: A disk cartridge with a shutter (10) connected to a slider (14) moveable on a guide portion provided on front side of a case for opening and closing an opening portion of the case, the slider (14) having a receiving recess (19) for receiving a drive pin provided in a read/writing device to move the shutter (10) together with the slider (14), the receiving recess (19) corresponding to an opening of the shutter (10); the case having a shutter locking mechanism for locking the shutter (10) at its closed position, the shutter locking mechanism comprising a stopping hole (53) provided, adjacent to the receiving recess (19), at a bottom portion of the slider (14), so as to partially communicate with the receiving recess (19), a stopper (59) having a head (60) supported on a leg portion (61), the head (60) passing through the stopping hole (53) to project partially into the receiving recess (19) of the shutter (10) when the shutter (10) is in a closed state and preventing the shutter from being moved in the opening direction; a room (56) provided at a position in the case, corresponding to the stopping hole (53) for accommodating a leg portion (61) of the stopper (59); and an elastic member (160) accommodated in the room (56) to urge the stopper (59) toward the slider, characterised in that the stopper (59) has a stopping piece (64) co-operating with a stopping projection (55) provided at a head end of the slider such that the stopper (59) cannot be moved in the releasing direction by a force exerted in the opening direction of the shutter; and the room (56) includes two guide walls (57) extended in a longitudinal direction of the case for guiding the leg portion (61). A disk cartridge according to claim 1, wherein the stopping hole (53) has a length larger than that of the receiving recess (19) in a longitudinal direction of the slider (14). A disk cartridge according to claim 1 or 2, wherein the stopping hole (53) has at its front end, a slanted ceiling wall (54) for engaging with a slanted wall (63) of the head (60) of the stopper (59). A disk cartridge according to one of claims 1 to 3, wherein the stopper (59) has a plate-like head (60) with a slanted wall (63). A disk cartridge according to one of claims 1 to 4, wherein a shoulder (Sh) is provided between the leg portion (61) and the head (60) of the stopper (59), the shoulder (Sh) being engaged with a wall of the case to keep the leg portion (61) in the room (56). A disk cartridge according to one of claims 1 to 5, wherein the stopping piece (64) and the stopping projection (55) are projected in a lateral direction of the case, respectively to reliably maintain the shutter (10) in its closed position. A disk cartridge according to one of claims 1 to 6, wherein the room (56) is provided adjacent to a surrounding wall for accommodating a disk.

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: B29C45, G11B23