Abstract:
A recording medium cartridge that includes a housing having an access opening that allows access to a recording medium contained in the housing, and a shutter movably attached to the housing to open/close the access opening of the housing. The housing is formed of upper and lower shell halves welded with each other at a plurality of spots on their peripheral walls, and the shutter is formed of upper and lower shell halves fitted with each other at their peripheral walls such that one is nested in the other. The upper and lower shutter halves are welded with each other at least at one spot. In addition, a method for manufacturing such a recording medium cartridge is also provided.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to a recording medium cartridge that includes a housing having an access opening that allows access to a recording medium contained in the housing, and a shutter movably attached to the housing to open/close the access opening of the housing, in which the housing is formed of upper and lower shell halves welded with each other at the peripheral walls thereof, and the shutter is formed of upper and lower shutter halves fitted with each other at the peripheral walls thereof such that one is nested in the other. The present invention is also directed to a manufacturing method for manufacturing such a recording medium cartridge.  
         [0003]     2. Description of the Related Art  
         [0004]     In the mobile devices, such as digital cameras and the like, a subminiature recording medium cartridge known as “Click!™” is used as the recording medium as described for example in U.S. Pat. No. 6,133,544.  
         [0005]     As shown in FIGS.  5  (perspective view),  6 A (plan view), and  6 B (bottom view), the aforementioned recording medium cartridge  1  includes a planar housing formed of a resin frame  2  known as a stabilizer having a pressing section  2   a  for pressing the cartridge with a finger when inserting the cartridge into a drive unit, an upper shell half  3  made of a thin metal plate (stainless steel plate of 0.3 mm thickness) which is fitted to the frame  2  and has a flat main surface, and a lower shell half  4 . The size of the housing is 50 mm (W)×55 mm (D) with the thickness of 1.95 mm. The housing movably contains a 40 MB disk-shaped magnetic recording medium  5  of 1.8 inches (45.7 mm) in diameter. A central hub (central core)  10  having a central through-hole is fixedly attached to the central region of the magnetic recording medium  5 .  
         [0006]     The recording medium cartridge  1  is designed to be loaded in a TYPE II PC card type drive unit (not shown) having outer dimensions of 53 mm (W)×85 mm (D) with the thickness of 5 mm by inserting it into the slot of the drive unit. The housing includes a v-shaped opening  6  that allows a read/write magnetic head of the drive unit to gain access to the surface of the magnetic recording medium  5 . A rotary shutter  7  having an opening  7   a  for rotatingly opening/closing the opening  6  is interposingly provided between the housing and magnetic recording medium  5 . The rotary shutter  7  is urged in the closing direction by a coil spring  16 , which will be described later with reference to  FIG. 9B , and formed such that it is locked at the closing position by a locking member (not shown) attached to the upper shell half  3 .  
         [0007]      FIGS. 5, 6A  and  6 B show the rotary shutter  7  in closing state, in which the opening  7   a  of the rotary shutter  7  is hidden in the housing, and the opening  6  is closed by the rotary shutter  7 .  
         [0008]     As shown in  FIG. 7 , which is an enlarged cross-sectional view of the relevant part of the cartridge taken along the line  7 - 7  in  FIG. 6A , the rotary shutter  7  includes an upper shutter half  7 U and a lower shutter half  7 D, each made of a thin aluminum plate, which are fitted together at the peripheral walls  7 Ub,  7 Db such that one is nested in the other. The upper shutter half  7 U is rotatably supported by a small diameter cylindrical body  3   a , which protrudes inwardly from the under surface of the upper shell half  3 . A retaining member  11  called central pin is welded at the end of the cylindrical body  3   a  in order to prevent the upper shutter half  7 U from falling out of the cylindrical body  3   a , which intrudes in the central through-hole  10   a  of the central hub  10 . A liner  13  made of unwoven cloth with a raised surface for cleaning the surface of the magnetic recording medium  5  is attached to the inner surface of each of the upper and lower shutter halves  7 U,  7 D.  
         [0009]     A round opening  4   a  is formed in the central region of the lower shell half  4  that allows the central hub  10  to face outside, and a large diameter cylindrical body  7 Da protruding downward is provided, which is loosely fitted to the rim of the opening  4   a . The lower shutter half  7 D is rotatably supported by the lower shell half  4  through the cylindrical body  7 Da, and the tip of the cylindrical body  7 Da is bent to form a flange  12  for preventing the lower shutter half  7 D from falling out of the lower shell half  4 .  
         [0010]     As is clear from  FIG. 6B , the lower shell half  7 D has an arc-shaped opening  4   b  which is formed concentrically with the rotary shutter  7 , and a shutter knob  7   b , which protrudes from the arc-shaped opening  4   b  and moves along the arc-shaped opening  4   b  to open/close the rotary shutter  7 , is fixedly attached to the lower shutter half  7 D. When the recording medium cartridge  1  is loaded (inserted) in the drive unit, the locking of the rotary shutter  7  by the locking member at the closing position is released and the rotary shutter  7  becomes turnable. At the same time, the engaging wall of the drive unit engages with the shutter knob  7   b  to rotate the rotary shutter  7  approximately by 60 degrees to the opening position where the opening  7   a  approximately corresponds to the opening  6  of the upper and lower shell halves  3 ,  4 . In this way, the cartridge  1  is loaded in the drive unit with the magnetic recording medium  5  being exposed from the opening  6  of the housing as shown in  FIG. 8A  (plan view) and  FIG. 8B  (bottom view).  
         [0011]     In  FIG. 7 , the magnetic recording medium  5  is brought into contact with the liner  13  of the lower shutter half  7 D due to the weight of the central hub  10 . When the recording medium cartridge  1  is loaded in the drive unit, however, the central hub  10  is magnetically and mechanically chucked by the drive spindle of the drive unit and the central hub  10  is held up so that the magnetic recording medium  5  is ratatably held at the position which is approximately intermediate of the gap between the surfaces of the upper and lower liners  13 .  
         [0012]     When the recording medium cartridge  1  loaded in the drive unit is further pushed toward the drive unit, the engagement with the drive unit is released to allow the cartridge to be unloaded. When the recording medium cartridge  1  is unloaded, the rotary shutter  7  is returned to the closing position shown in  FIGS. 6A and 6B  by the coil spring  16 .  
         [0013]     As shown at the right edge of the drawing in  FIG. 7 , the upper and lower shell halves  3 ,  4  are put together by spot welding with the edges of the peripheral walls  3   s ,  4   s  being abutted with each other. The spot welding is performed using a laser beam at 13 welding spots W 1  to W 13  along the abutting line as shown in  FIG. 6A . The welded spot is indicated by the reference mark W in  FIG. 7 .  
         [0014]      FIG. 9A  is an enlarged plan view of the frame, and  FIG. 9B  is an enlarged plan view of the frame and lower shutter half  7 D illustrating the coil spring being mounted between the frame and lower shutter half  7 D for urging the rotary shutter  7  in the closing direction.  
         [0015]     A guide wire  15  is inserted through the coil spring  16 , and both ends of the wire  15  are press fitted respectively in a groove G of a locking section  2   b  and a groove G of a locking section  2   c  formed on the frame  2 . Dilated sections  15   a ,  15   b  are provided at the ends of the wire  15  by flattening the ends in order to prevent the wire  15  from falling out of the grooves G. Each of the dilated sections  15   a ,  15   b  has a suitable size that allows the wire  15  to be inserted through the coil spring  16 .  
         [0016]     The lower shutter half  7 D has a radially-outwardly protruding engaging projection  17  for the upper shutter half  7 U, which is integrally formed at a place of the peripheral wall  7 Db. A cylindrical spring locking section  18  is formed at the tip of the engaging projection  17 . The guide wire  15  is inserted through the spring locking section  18  to allow the spring locking section  18  to slide along the guide wire  15 . The coil spring  16  is compressedly mounted between a locking wall  2   d  formed in one of the locking section  2   b  of the frame  2  and spring locking section  18  to urge the lower shutter half  7 D in the closing direction. The other locking section  2   c  includes a locking wall  2   e  which is abutted by the spring locking section  18  to hold the lower shutter half  7 D at the closing position.  
         [0017]     In the mean time, the peripheral wall  7 Ub of the upper shutter half  7 U is fitted to the peripheral wall  7 Db as shown in  FIG. 7 , and the upper shutter half  7 U includes a notch  19  which is fitted to the engaging projection  17  to corotate with the lower shutter half  7 D as shown in  FIG. 10 .  
         [0018]     In the conventional recording medium cartridge  1  described above, the upper and lower shutter halves  7 U,  7 D are configured to coroate by engaging the engaging projection  17  formed integrally with the spring locking section  18  provided in the lower shutter half  7 D with the notch  19  formed in the peripheral wall  7 Ub of the upper shutter half  7 U. This configuration degrades the robustness and accuracy of the shutter. In addition, it has a problem that the upper and lower shutter halves  7 U,  7 D may be misaligned in up-down directions, since they are merely fitted together at the peripheral walls  7 Ub,  7 Db.  
         [0019]     In view of the circumstances described above, it is an object of the present invention to provide a recording medium cartridge that eliminates the engaging structure for the upper and lower shutter halves in the moving direction to improve the robustness and accuracy of the shutter, as well as preventing misalignment of the shutter halves in up-down directions. It is a further object to provide a manufacturing method for manufacturing such a recording medium cartridge.  
       SUMMARY OF THE INVENTION  
       [0020]     The recording medium cartridge according to the present invention is a recording medium cartridge, comprising:  
         [0021]     a housing having an access opening that allows access to a recording medium contained therein; and  
         [0022]     a shutter movably attached to the housing to open/close the access opening of the housing,  
         [0000]     wherein:  
         [0023]     the housing is formed of upper and lower shell halves welded with each other at a plurality of spots on the peripheral walls thereof, and the shutter is formed of upper and lower shutter halves fitted with each other at the peripheral walls thereof such that one is nested in the other; and  
         [0024]     the upper and lower shutter halves are welded with each other at least at one spot.  
         [0025]     Preferably, the shutter is a rotary shutter rotatably attached to the inside of the housing.  
         [0026]     Further, the upper and lower shutter halves are preferably welded with each other at least at one spot in the fitted section of the peripheral walls.  
         [0027]     Still further, the rotary shutter is preferably further rotatable through the opening position in the direction opposite to the closing direction by a predetermined angle of approximately 10 degrees.  
         [0028]     Preferably, the upper and lower shutter halves are welded together in the area adjacent to the leading edge of the rotary shutter which is exposed to the access opening of the housing when the rotary shutter is further rotated through the opening position in the direction opposite to the closing direction by the predetermined angle.  
         [0029]     Further, the upper and lower shell halves are preferably made of stainless steel, and the upper and lower shutter halves are made of aluminum.  
         [0030]     Still further, the recording medium is preferably a rotatable disk having an outer diameter of 1 inch (approximately, 25 mm) or 0.8 inches (approximately, 20 mm) contained in the rotary shutter.  
         [0031]     The manufacturing method according to the present invention is a method for manufacturing a recording medium cartridge, comprising the steps of:  
         [0032]     forming a housing having an access opening that allows access to a recording medium contained therein by welding upper and lower shell halves with each other at a plurality of spots on the peripheral walls thereof;  
         [0033]     forming a rotary shutter rotatably attached to the housing to open/close the access opening of the housing by fitting upper and lower shutter halves with each other at the peripheral walls thereof such that one is nested in the other; and  
         [0034]     welding the upper and lower shutter halves with each other at least at one spot in the fitted section of the peripheral walls thereof simultaneously with the welding of the upper and lower shell halves or in a series of welding processes before or after the welding of the upper and lower shell halves.  
         [0035]     Preferably, the welding of the upper and lower shell halves is performed by a spot welding process using a laser beam in which edges of the peripheral walls of the upper and lower shell halves are abutted with each other, and the welding is implemented at a plurality of spots along the abutting line.  
         [0036]     Further, the welding of the upper and lower shutter halves is preferably performed by a spot welding process using a laser beam.  
         [0037]     Still further, the welding of the upper and lower shutter halves is preferably implemented in the area of the upper and lower shutter halves which is hidden inside of the upper and lower shell halves when the shutter is in closing position.  
         [0038]     Preferably, the rotary shutter is further rotatable through the opening position in the direction opposite to the closing direction by a predetermined angle of approximately 10 degrees, and the welding of the upper and lower shutter halves is implemented in the area adjacent to the leading edge of the rotary shutter which is exposed to the access opening of the housing when the rotary shutter is further rotated through the opening position in the direction opposite to the closing direction by the predetermined angle.  
         [0039]     According to the present invention, the upper and lower shutter halves are welded with each other at least at one spot. This may eliminate the engaging structure for the upper and lower shutter halves in the moving direction. This may not only improve the robustness and accuracy of the shutter but also prevent the misalignment of the upper and lower shutter halves in up-down directions. Further, this may result in more space available in the housing.  
         [0040]     Further, the welding of the upper and lower shutter halves is performed simultaneously with the welding of the upper and lower shell halves or in a series of welding processes before or after the welding of the upper and lower shell halves, so that the welding of the upper and lower shutter halves may be implemented without any appreciable cost increase.  
         [0041]     Still further, the welding of the upper and lower shutter halves is implemented in the area of the upper and lower shutter halves which is hidden inside of the upper and lower shell halves when the shutter is in closing position, so that degradation of the appearance of the cartridge due to the welding of the upper and lower shutter halves may be avoided. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0042]      FIG. 1A  is a plan view of a recording medium cartridge according to the present invention.  
         [0043]      FIG. 1B  is a bottom view of the recording medium cartridge according to the present invention.  
         [0044]      FIG. 2  is an enlarged cross-sectional view of the relevant part of the cartridge shown in  FIG. 1 .  
         [0045]      FIG. 3  is a front view of a holding rod used when the upper and lower shell halves are welded.  
         [0046]      FIG. 4A  is a plan view of the recording medium cartridge according to the present invention, illustrating the location of the upper and lower shutter halves when they are welded with each other.  
         [0047]      FIG. 4B  is a bottom view of the recording medium cartridge according to the present invention, illustrating the location of the upper and lower shutter halves when they are welded with each other.  
         [0048]      FIG. 5  is a perspective view of a conventional recording medium cartridge to which the present invention is applied.  
         [0049]      FIG. 6A  is a plan view of the recording medium cartridge shown in  FIG. 5 , illustrating the rotary shutter thereof is in closing position.  
         [0050]      FIG. 6B  is a bottom view of the recording medium cartridge shown in  FIG. 5 , illustrating the rotary shutter thereof is in closing position.  
         [0051]      FIG. 7  is an enlarged cross-sectional view of the relevant part of the recording medium cartridge taken along the line  7 - 7  in  FIG. 6A .  
         [0052]      FIG. 8A  is a plan view of the recording medium cartridge shown in  FIG. 5 , illustrating the rotary shutter thereof is in opening position.  
         [0053]      FIG. 8B  is a bottom view of the recording medium cartridge shown in  FIG. 5 , illustrating the rotary shutter thereof is in opening position.  
         [0054]      FIG. 9A  is an enlarged plan view of the frame of the recording medium cartridge shown in  FIG. 5 .  
         [0055]      FIG. 9B  is an enlarged plan view of the frame and lower shutter half, illustrating a coil spring being mounted between the frame and lower shutter half for urging the rotary shutter in the closing direction.  
         [0056]      FIG. 10  is an enlarged perspective view of the recording medium cartridge shown in  FIG. 5 , illustrating an engaging structure for the upper and lower shutter halves. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0057]     Hereinafter, an illustrative embodiment of the present invention will be described in detail with reference to the accompanying drawings.  
         [0058]      FIG. 1A  is a plan view and  FIG. 1B  is a bottom view of a recording medium cartridge according to the present invention.  
         [0059]      FIG. 2  is an enlarged cross-sectional view of the relevant part of the cartridge shown in  FIG. 1 . The recording medium cartridge shown in  FIGS. 1A, 1B  and  2  has no engaging structure in the fitted section of the peripheral walls  7 Ub,  7 Db of the upper and lower shutter halves  7 U,  7 D for the upper and lower shutter halves in the rotational direction. It has a substantially identical structure to that of the recording medium cartridge already described with reference to  FIGS. 6A, 6B  and  7 , other than that the upper and lower shutter halves are welded with each other at least at one spot W 0 . Therefore, the identical members are given the same reference numerals and will not be elaborated upon further here.  
         [0060]     If the welding spot W 0  of the peripheral walls  7 Ub,  7 Db of the upper and lower shutter halves  7 U,  7 D is set in an area which is exposed from the opening  6  of the housing when the rotary shutter  7  is in closing position, the welding may be implemented easily, but it may degrade the appearance of the cartridge due to the welded spot. Consequently, in the present embodiment, the welding spot W 0  is set in an area which is hidden inside of the housing when the rotary shutter is in closing position as shown in  FIGS. 1A and 1B .  
         [0061]     When performing spot welding using a laser beam at 13 spots W 1  to W 13  shown in  FIG. 6A  in the abutting section of the peripheral walls  3   s ,  4   s  of the upper and lower shell halves  3 ,  4 , the welding is performed with the upper shell half  3  of the housing fixed on a movable platform (not shown) being pressed from above in the vicinity of each of the 13 welding spots W 1  to W 13  around the periphery of the main surface thereof using 13 holding rods  40  mounted in a rod holding member  50  as shown in  FIG. 3 .  
         [0062]     Each of the holding rods  40  shown in  FIG. 3  includes a rod body  41  having a hemispherical lower end face  41   a  that touches the upper shell half  3  in the vicinity of each of the 13 welding spots W 1  to W 13  around the periphery of the main surface thereof, an outer casing  42  through which the rod body  41  is slidably mounted in up-down directions and has a thread groove on the outer circumference to be adjustably mounted in up-down directions in the rod holding member  50 , a shoulder formed at the rod body  41   b , a coil spring  43  compressedly mounted between the shoulder  41   b  and a flange  42   a  of the outer casing  42 , and an adjusting nut  44  sprirally mounted on the upper end section  41   c  of the rod body  41  for adjusting the spring pressure of the coil spring  43 .  
         [0063]     The 13 holding rods  40  constructed in the manner as described above are mounted in the rod holding member  50 , so that the position of the lower end face  41   a  of each of the rod bodies  41  relative to the periphery of the main surface of the upper shell half  3  and the contact pressure thereof may be adjusted on a rod by rod basis.  
         [0064]     The welding at the 13 spots W 1  to W 13  in the abutting section of the peripheral walls  3   s ,  4   s  of the upper and lower shell halves  3 ,  4  and at one welding spot W 0  on the peripheral walls  7 Ub,  7 Db of the upper and lower shutter halves  7 U,  7 D may be performed simultaneously or sequentially. But the sequential welding, in which the welding is performed one spot after another, is more advantageous in that it may be performed with a simpler optics system for irradiating the laser beam. In this case, work is fixed on a rotating platform which is movable relative to the optics system and the welding may be performed at each of the welding spots.  
         [0065]     When performing the welding of the peripheral walls  7 Ub,  7 Db of the upper and lower shutter halves  7 U,  7 D, the relative positions between the shutter knob  7   b  and arc-shaped opening  4   b  may be preset such that the rotary shutter may further turn in the clockwise direction in  FIG. 8A  (counterclockwise direction in  FIG. 8B ) through the opening position shown in  FIGS. 8A and 8B  by a predetermined angle (around 10 degrees) if required. Then, the upper and lower shutter halves  7 U,  7 D fitted with each other at their peripheral walls  7 Ub,  7 Db are turned from the closing position shown in  FIGS. 6A and 6B  to the position shown in  FIGS. 4A and 4B  through the opening position shown in  FIGS. 8A and 8B  to expose the area adjacent to the leading edge of the opening  7   a  in the rotational direction to the opening  6  of the housing. In this way, the welding may be performed in the area of the peripheral walls of the upper and lower shutter halves  7 U,  7 D which is exposed to the opening  6  of the housing. By doing so, the welded spot W 0  may be hidden inside of the housing when the shutter  7  is in closing position. This may prevent degradation of the appearance due to exposure of the welded spot W 0 .  
         [0066]     In the mean time, a small gap is present at the abutting section of the peripheral walls  3   s ,  4   s . This may cause a problem that the weld slag of a metal melted at the welding and the like enter through the gap and contaminate the magnetic recording medium. In this case, of the 13 welding spots W 1  to W 13  of the upper and lower shell halves  3 ,  4  shown in  FIG. 6   a , the welding spots W 4  to W 13  locate where the peripheral walls  7 Ub,  7 Db of the upper and lower shutter halves  7 U,  7 D are overlappingly fitted with each other as is clear from  FIGS. 2 and 7 . Consequently, the peripheral walls  7 Ub,  7 Db of the upper and lower shutter halves  7 U,  7 D may serve as a shield and the magnetic recording medium  5  is protected from the weld slag and the like when the welding at these spots is implemented. On the other hand, when the rotary shutter  7  is in closing position, the opening  7   a  thereof locates opposite to the welding spots W 1  to W 3  as is clear from  FIG. 6A . If welding is performed at the welding spots W 1  to W 3  under this condition, the magnetic recording medium  5  may be contaminated.  
         [0067]     Accordingly, if the welding at the welding spot W 0  on the peripheral walls  7 Ub,  7 Db of the upper and lower shutter halves  7 U,  7 D and at the welding spots W 1  to W 3  is performed after the rotary shutter  7  is turned to the position shown in  FIGS. 4A and 4B , the contamination problem of the magnetic recording medium may be avoided.  
         [0068]     In the present embodiment, the upper and lower shell halves  3 ,  4  are made of stainless steel plates, and the upper and lower shutter halves  7 U,  7 D are made of thin aluminum plates. This may require a slight change in the welding conditions between them, but the upper and lower shutter halves  7 U,  7 D may be welded without any appreciable const increase by performing the welding of the upper and lower shell halves  3 ,  4 , and the upper and lower shutter halves  7 U,  7 D in a series of welding processes using the same welding unit.  
         [0069]     The welding of the upper and lower shutter halves  7 U,  7 D at least at one spot may eliminate the engaging structure for the upper and lower shutter halves in the moving direction. This may not only improve the robustness and accuracy of the shutter  7  but also prevent the misalignment of the upper and lower shutter halves in up-down directions. Further, this may result in more space available in the housing.  
         [0070]     The present embodiment described above is an illustrative example of “Click!” which has a magnetic recording medium  5  with the external diameter of 1.8 inches (approximately 46 mm). But the present invention is not limited to the specific embodiment as illustrated herein. For example, the present invention is applicable to cartridges having ultracompact high density recording media including smaller and high density medium of 1 inch (approximately 25 mm) and of 0.8 inches (approximately 20 mm) to be developed in the future. Further, the recording medium is not limited to a disk, and it may be a tape, hard disk, optical medium, semiconductor, and the like.  
         [0071]     In the illustrative embodiment described above, the rotary shutter  7  is built in the housing. It is obvious that the present invention may also be applied to a recording medium cartridge having an externally provided rotary or sliding shutter.