Shutter locking mechanism for floppy disc drive

Abstract: A shutter locking mechanism for a FDD capable of securely keeping the shutter in opened state against any external impact. This mechanism comprises a pivot secured to the carrier for axially and rotatably supporting the shutter opening lever, and a projecting portion formed at the distal end of the shutter opening lever and fit to an aperture existing at the shutter opening lever contact side of the shutter in the loading position. The projecting portion enters the aperture at the right corner of the shutter in the loaded position while at the left corner claw portions of the stopper hold the shutter for preventing the distal end of the shutter opening lever from separating from the shutter.

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention: This invention relates to a mechanism for locking the shutter of a floppy disc (hereinafter referred as "FD") when it is in the opened state in a floppy disc drive (hereinafter referred as "FDD"). 2. Description of the Related Art: Recently, a FDD has been remarkably improved in terms of size and weight so that its is widely used as an essential component incorporated into office automation appliances. While having proven sophistication as a handy and portable component, it is required to be resilient to heavy usage. FIGS. 5 and 6 are plan and side views respectively showing essential parts of a conventional FDD. In FIG. 6, a slide plate 20 is mounted on a frame 10 having a groove 11. in the inserting direction of the FD. The slide plate 20 having a diagonal groove 21 acts to guide the pin implanted on the carrier 30 cooperating with the groove 11 of the frame 10 in order to move the FD 40 from an unloaded state shown by solid lines to a loaded state shown by two-dot chain lines. A normally used FD 40 includes a not shown magnetic disc contained within a cartridge 41 having an opening 46 at both sides thereof. The shutter 42 is always biased by a not shown spring in the direction from the left corner 44 to the right corner 43 of the FD 40. In the unloaded state, the shutter 42 covers the head contact portion 47 to protect the magnetic disc by not superimposing the window 45 on the opening 46. When the FD 40 is inserted into the carrier 30 and reaches a position near the loaded position, the distal end 51 of the shutter opening lever 50 axially and rotatably supported by a pivot implanted on the frame 10 comes into contact with the right corner 43 of the shutter 42. Further insertion of the FD 40 against the bias force of the spring 13 moves the shutter 42 toward the left corner 44 until arriving at the loaded position. In this state, the window 45 and the opening 46 lie on top of one another to expose the head contact portion 47 of the FD 40 in order to enable the data recording/reproducing operation by a not shown head which contacts with both sides of the magnetic disc. In the loaded state, the shutter 42 is biased toward the right corner 43 by the not shown spring incorporated in the cartridge 41 to contact with the distal end 51 of the shutter opening lever 50. The distal end 51, composed of a cylindrical surface having a small radius, contacts with the cartridge 41 and the corner 43, and is biased only by the above-mentioned incorporated spring and the spring 13 of the shutter opening lever 50. Therefore, when any external impact is applied on the FD 40, the distal end 51 will easily separate from the right corner 43 to close the shutter 42 and would damage the magnetic head by the window 45 of the shutter 42 moving to the closed position. EP-A-0 407 140, in particular the figs. 1, 7, 32, 33 and 34 thereof, discloses a shutter locking mechanism for a floppy disc drive in which a carrier 3 for holding a floppy disc 6 can be lead to an unloaded position or a loaded position by a cam guide system 83a, 84, and in which ashutter opening lever 4 is provided which is capable of opening a shutter 11 of the floppy disc 6 to enable the contact/separation of a magnetic head to/from the floppy disc 6 when the latter is near to the loaded position. In particular, the known shutter mechanism comprises a pivot 4b secured to the carrier 3 for axially and rotatably supporting the shutter opening lever 4, a projecting portion 4a formed at the distal end of the shutter opening lever 4 and adapted to fit in an aperture located at the shutter opening lever contact side of the shutter 11, when the floppy disc 6 is in the loaded position, and a stopper 52 one end of which is secured to the carrier 3, and the other end of which is formed as a bifurcated claw portion 52a, 52b, for holding the shutter 11 via a head insertion portion 35 of a slider 22 fixed to the shutter 11 in its open position when the floppy disc 6 is in the loaded position. One particular disadvantage of this state of the art consists in that, due to positional tolerances, the head insertion portion 35 of the slider 22 may not properly be inserted between the bifurcated claw portions 52a, 52b of the stopper 52 upon loading the floppy disc 6, or may be separated from the stopper 52 when an external impact is applied to the loaded floppy disc 6, so that the shutter 11 may damage the magnetic head. SUMMARY OF THE INVENTION It is therefore an object of the present invention to further develop the shutter locking mechanism according to EP-A-0 407 140 to the effect that the shutter is securely kept in the opened state when the floppy disc is loaded. This object is solved by the features indicated in the characterizing portion of independent claim 1. According to the invention, the stopper 60 is arranged to act on one face of the shutter 42 when the latter is in its open position, and the bifurcated claws 61, 62 are of different lenghts in order to accommodate any positioning tolerances. Thus, proper loading of the floppy disc 40 is assured, whilst the shutter 42 is securely kept in its open state when the floppy disc 40 is loaded. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view showing a FD and essential parts of a shutter locking mechanism in a FDD according to an embodiment of this invention; FIG. 2 is a side view showing essential parts of the shutter locking mechanism in FIG. 1; FIG. 3 is a diagram showing enlarged essential parts around the distal end of the shutter opening lever shown in FIG. 1; FIG. 4 is a diagram showing enlarged essential parts around the claw portions of the stopper; FIG. 5 is a plan view showing a FD and essential parts of a conventional shutter locking mechanism in a FDD; and FIG. 6 is a plan view showing essential parts of the shutter locking mechanism in FIG. 5. DETAILED DESCRIPTION The principles of this invention are particularly useful when embodied in a shutter locking mechanism as shown in FIGS. 1 through 4. FIG. 1 is a plan view showing essential parts of the shutter locking mechanism of this invention, FIG. 2 is a side view of the mechanism shown in FIG. 1, FIGS. 3 and 4 are enlarged views of the distal end of the shutter opening lever in the loaded state and of the stopper. In FIGS. 5 and 6, the same components are designated by the same numerals without duplicated description. In FIGS. 1 through 4, a pivot 32 for axially and rotatably supporting the shutter opening lever 50 is secured to the carrier 30. As a significant feature of this invention, a projecting portion 52 is formed at the distal end 51 of the shutter opening lever 50 to enter the aperture at the corner 43 of the shutter 42. On the other hand, near the left corner 44 of the shutter 42, the carrier 30 is provided with a stopper 60 welded or rivetted at the fixing portion 65. The stopper 60 has a bifurcated spring portion 63, 64, the distal ends of which are formed as claws 61, 62 for holding the left corner 44 of the shutter 42 in the loading state as described hereinafter. In operation, as shown in FIG. 2, the pivot 32 and the stopper 60 are secured to the carrier 30. On insertion of the FD 40 into the carrier 30, the distal end 51 of the shutter opening lever 50 firstly contacts with the right corner 43 of the shutter 42 and moves the shutter 42 toward the left corner 44. Close to the fully loaded position, the claw 61 of the stopper 62 comes to catch the cartridge 41 against the bias force of the spring portion 64. Further, just before the fully loaded position, the other claw 61 comes to catch the shutter 42, thereby reaching the fully loaded state shown by two-dot chain lines. The shutter 42 is securely held at the left and right corners 43, 44 by the distal end 51 of the shutter opening lever 50 and by the claws 61, 62. In this state, the projecting portion 52 of the distal end 51 enters the aperture existing in the shutter 42 so as to scarcely allow the shutter to move in the direction of the corners 43, 44. As a result, the distal end 51 would not get out of the corner 43 even when strong impacts are applied. The claw 62 is formed at the distal end of the spring portion 64 slightly shorter than the other spring portion 63, and acts to absorb the dispersion of the stopping position of the left corner 44. In the shown embodiment, the present invention has been applied to a FDD in which the carrier is guided to the unloaded and loaded positions by a cam provided in the frame and the sliding plate. Alternatively, of course, it is also possible to use this invention in a FDD where a link mechanism is used instead of the cam. As mentioned above, according to this invention, the shutter of the FD held open in the loaded state would not accidentally or easily close due to any undesirable external impacts, by inserting the projecting portion formed at the distal end of the shutter opening lever into the aperture existing in the shutter, or in addition thereto by holding the opposed corner of the shutter by claws formed at the distal end of the stopper.

Claims: A floppy disc drive in which a carrier (30) for holding a floppy disc (40) can be lead to an unloaded position or a loaded position by a cam guide system (21) or a link system, and in which a shutter locking mechanism having a shutter opening lever (50) is provided which is capable of opening a shutter (42) of said floppy disc (40) to enable the contact/separation of a magnetic head to/from said floppy disc (40) when the latter is near to said loaded position, said shutter mechanism comprising a pivot (32) secured to said carrier (30) for axially and rotatably supporting said shutter opening lever (50), a projecting portion (52) formed at the distal end (51) of said shutter opening lever (50) and adapted to fit in an aperture located at the shutter opening lever contact side of said shutter (42), when said floppy disc (40) is in said loaded position, and a stopper (60) one end of which is secured to said carrier (30), and the other end of which is formed as a bifurcated claw portion (61, 62), for holding said shutter (42) in its open position when said floppy disc (40) is in said loaded position, characterized in that said stopper (60) is arranged to act on one face of said shutter (42) when the latter is in its open position, and that the bifurcated claws (61, 62) are of different lengths in order to accommodate any positioning tolerances.

Inventors: MABUCHI HIROSHI, WAKITA MAKI, MABUCHI, HIROSHI, WAKITA, MAKI
Applicants: CITIZEN WATCH CO LTD, CITIZEN WATCH CO. LTD.
Application year: 1992
Main classification: G11B17
IPC codes: G11B23, G11B17