Abstract:
The opening and closing device involves a stationary member, a stationary cam, a rotary cam, a rotary member, a spring disposed between the stationary member and the stationary cam which pushes the stationary cam against the rotary cam, and a shaft passing through the stationary member, the stationary cam, the spring, the rotary cam and the rotary member. A head of the shaft holds the stationary member or the rotary member rotatably at its first end, and a caulked portion of the shaft fixes the shaft to the rotary member or the stationary member at its second end. Upon opening or closing operation, the stationary member or the rotary member, which is fixed to the shaft, rotates with the shaft integrally, causing no wear. The opening and closing device can realize smooth and sure operation without irregular feeling.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to an opening/closing device for use in a variety of electronic equipment such as cell-phones, video cameras or the like.  
       BACKGROUND ART  
       [0002]     In recent years, the downsizing and the greater functionality of electronic equipment such as cell-phones, video cameras or the like are advancing rapidly. Along with the advances, many types of electronic equipment can open or close by rotating the movable housings against the stationary housings. The opening/closing device, as disclosed in Japanese Patent Unexamined Application No. 2002-206520, comes to be required to have a higher durability as well as compact size and light weight.  
       SUMMARY OF THE INVENTION  
       [0003]     The opening/closing device involves a stationary member, a stationary cam, a rotary cam, a rotary member, a spring disposed between the stationary member and the stationary cam which pushes the stationary cam against the rotary cam, and a shaft passing through the stationary member, the stationary cam, the spring, the rotary cam and the rotary member. A head of the shaft holds the stationary member or the rotary member rotatably at its first end, and a caulked portion of the shaft fixes the shaft to the rotary member or the stationary member at its second end. Upon opening/closing operation, the stationary member or the rotary member, which is fixed to the shaft, rotates with the shaft integrally, causing no wear. The opening/closing device can realize smooth and reliable operation without any sense of resistance or the like. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0004]      FIG. 1  shows a cross-sectional view of the opening/closing device used in an exemplary embodiment of the present invention.  
         [0005]      FIG. 2  shows an exploded perspective view of the opening/closing device used in an exemplary embodiment of the present invention.  
         [0006]      FIGS. 3A, 3B  and  3 C show partial perspective views of the opening/closing device used in an exemplary embodiment of the present invention.  
         [0007]      FIGS. 4A, 4B  and  4 C show partial perspective views of the opening/closing device used in an exemplary embodiment of the present invention.  
         [0008]      FIG. 5  shows a cross-sectional view of a comparative example of an opening/closing device.  
         [0009]      FIG. 6  shows an exploded perspective view of a comparative example of an opening/closing device. 
     
    
     DESCRIPTION OF THE INVENTION  
       [0010]     First, a comparative example of an opening and closing (opening/closing) device is described with reference to  FIGS. 5 and 6 . The comparative example of the opening/closing device is what the inventors of the present invention have developed for downsizing and weight saving of electronic equipment.  
         [0011]      FIG. 5  shows a cross-sectional view of the comparative example of the opening/closing device, and  FIG. 6  shows an exploded perspective view of the same. The comparative example of the opening/closing device includes generally plate-like stationary member  1  and generally disc-like stationary cam  2  with a plurality of convex cam parts  2 A formed on the top surface. Through-holes  1 A and  2 B are formed in the center of stationary member  1  and stationary cam  2  respectively. Protrusions  2 C formed on the bottom surface of stationary cam  2  are inserted into mounting-holes  1 B formed outside of through-hole  1 A of stationary member  1 , so that stationary cam  2  is mounted on the top surface of stationary member  1 .  
         [0012]     Opening/closing device  10  further includes generally plate-like rotary member  3  and generally disc-like rotary cam  4  with a plurality of concave cam parts  4 A formed on the bottom surface. Through-holes  3 A and  4 B are formed in the center of rotary member  3  and rotary cam  4  respectively. Protrusions  4 C formed on the top surface of rotary cam  4  are inserted into mounting-holes  3 B formed outside of through-hole  3 A of rotary member  3 , so that rotary cam  4  is mounted on the bottom surface of rotary member  3 .  
         [0013]     Opening/closing device  10  still further includes coiled spring  5 . Spring  5  is disposed between the top surface of stationary member  1  and stationary cam  2  in a slightly contracted condition. Spring  5  pushes stationary cam  2  upward, pressing cam parts  2 A formed on the top surface of stationary cam  2  to engage cam parts  4 A formed on the bottom surface of rotary cam  4 .  
         [0014]     Opening/closing device  10  further includes a hollow cylindrical shaft  6  made of a metal. Cylindrical part  6 A of shaft  6  passes through-hole  1 A of stationary member  1 , spring  5 , through-hole  2 B of stationary cam  2 B, through-hole  4 B of rotary cam  4  and through-hole  3 A of rotary member  3 . Shaft  6  has head  6 B with a larger outer diameter than cylindrical part  6 A in its lower end, and the top surface of head  6 B abuts to the bottom surface of stationary member  1 .  
         [0015]     The upper end of cylindrical part  6 A of shaft  6  is spread out for caulking by using generally conical punch or the like (not shown) as shown in  FIG. 5 . Spread portion  6 C is formed to have a larger outer diameter than cylindrical part  6 A as well as through-hole  3 A. Rotary member  3  that has been caulked to shaft  6  keeps a distance against stationary member  1 . Within the distance, stationary cam  2  and rotary cam  4  are held so that stationary cam  2  can move vertically, and stationary member  1  and rotary member  3  are held on shaft  6  rotatably. However, shaft  6  is not fixed to rotary member  3  in opening/closing device  10 . The above is the configuration of a comparative example of opening/closing device  10 .  
         [0016]     Opening/closing device  10  with the above configuration is used in such devices as cell-phones, video cameras or the like, which have a stationary housing and a rotary housing. Stationary member  1  is fixed to the stationary housing (not shown) provided with a plurality of operating parts, a micro-phone or the like, and rotary member  3  is fixed to a rotary housing (not shown) provided with a display, a speaker, a camera or the like. Such opening/closing device  10  enables electronic equipment to open or close the rotary housing against the stationary housing.  
         [0017]      FIG. 6  illustrates an example when cam parts  2 A and  4 A of opening/closing device  10  engage at the angular positions of 0, 90, 180 and 270 degree. Next, the operation of opening/closing device with such configuration is described.  
         [0018]     A condition when rotary member  3  is laid on stationary member  1  in parallel longitudinary, or when the rotary housing is closed on stationary housing, is taken as the angular position of 0 degree.  
         [0019]     Upon turning the rotary housing from the angular position of 0 degree to the opening direction, rotary cam  4  rotates together with rotary member  3 . When rotary cam  4  rotates just 90 degrees, concave cam parts  4 A provided on the bottom surface of cam  4  comes to engage with convex cam parts  2 A provided on the top surface of cam  2 , and rotary member  3  is once held at the opening position of just 90 degrees.  
         [0020]     When rotary member  3  rotates further from the angular position of 90 degrees, stationary cam  2  moves down, cam parts  4 A released from cam parts  2 A, and rotary cam  4  rotates. After turning another 90 degrees where angular position is 180 degrees from the closed condition (0 degree), cam parts  2 A pushed by spring  5  comes to engage cam parts  4 A, and then rotary member  3  is stopped.  
         [0021]     Namely, by turning rotary member  3  fixed to the rotary housing of electronic equipment, the rotary housing opens and closes against stationary housing. Depending on the relative angular position between rotary cam  4  fixed to rotary member  3  and stationary cam  2  fixed to stationary member  1 , the rotary housing can be held at a predetermined angular position such as 0, 90, 180 degree or the like.  
         [0022]     In the aforementioned comparative example of opening/closing device, however, head  6 B provided on the lower end of shaft  6  only contacts to the bottom surface of stationary member  1 . Also, spread portion  6 C formed at the upper end of shaft  6  only contacts to rotary member  3 . As shaft  6  does not function to limit the rotation of stationary member  1  or rotary member  3 , wears between head  6 B and the bottom surface of stationary member  1  and wears between spread portion  6 C and the top surface of rotary member  3  are caused after repeating the opening/closing operation. When the wears becomes worse, the opening/closing operation becomes malfunctioned with irregular feeling.  
         [0023]     The present invention is aiming at improving the durability and operability of the opening/closing device in the comparative example with keeping the features of downsizing and weight saving.  
         [0024]     Next, the exemplary embodiments of the present invention are described with reference to FIGS.  1  to  4 . Elements similar to the elements used to describe the comparative example of the opening/closing device have the same reference marks and the description is simplified.  
       EXEMPLARY EMBODIMENTS  
       [0025]      FIG. 1  shows a cross-sectional view of the opening/closing device used in exemplary embodiment 1 of the present invention and  FIG. 2  shows an exploded perspective view of the same. Opening/closing device  20  used in exemplary embodiment 1 of the present invention includes: stationary member  1 , or the first board, formed generally plate-shaped using a metal such as steel, copper-alloy or the like; and stationary cam  2  (first cam) formed generally disc-shaped using a metal such as steel, copper alloy or the like and provided with a plurality of convex cam parts  2 A on its top surface. Through-holes  1 A and  2 B are formed in the center of stationary member  1  and stationary cam  2  respectively. Protrusions  2 C formed on the bottom surface of stationary cam  2  are inserted into mounting-holes  1 B formed outside of through-hole  1 A of stationary member  1  to mount stationary cam  2  on the top surface of stationary member  1 .  
         [0026]     Opening/closing device  20  further includes rotary member  13 , or the second board, formed generally plate-shaped using a metal such as steel, copper-alloy or the like. Through-hole  13 B provided with at least one notch  13 A dented outwardly is formed in the center of rotary member  13 . Mounting-holes  13 C are formed outside of through-hole  13 B.  
         [0027]     Opening/closing device  20  still further includes rotary cam  4  made of a metal such as steel, copper-alloy or the like, formed generally disc-shape. Rotary cam  4  (second cam) has a plurality of concave cam parts  4 A on its bottom surface and additionally has through-hole  4 B formed in the center. Protrusions  4 C formed on the top surface of rotary cam  4  are inserted into mounting-holes  13 C formed on stationary member  13  to mount rotary cam  4  on the bottom surface of rotary member  13 .  
         [0028]     Opening/closing device  20  further includes spring  5  made of a coiled steel wire. Spring  5  is disposed between the top surface of stationary member  1  and stationary cam  2  in a slightly contracted condition. Spring  5  performs to push stationary cam  2  upward and presses cam part  2 A to cam part  4 A formed on the bottom surface of rotary cam  4 . Also, cam part  2 A and cam part  4 A eangage each other.  
         [0029]     Opening/closing device  20  still further includes a hollow shaft  16  made of a metal such as steel, copper-alloy or the like in cylindrical shape. Cylindrical part  16 A of shaft  16  passes through-hole  1 A, spring  5 , through-hole  2 B of stationary cam  2 , through-hole  4 B of rotary cam  4  and through-hole  13 B of rotary member  13 . Shaft  16  has head  16 B with a larger outer diameter than cylindrical part  16 A on its lower end.  
         [0030]     The upper end of cylindrical part  16 A of shaft  16  is spread out for caulking by using generally conical punch or the like (not shown) as shown in  FIG. 1 . Spread portion  6 C is formed to have a larger outer diameter than cylindrical part  16 A as well as through-hole  13 B. Rotary member  13  that has been caulked to shaft  6  keeps a distance against stationary member  1 . Within the distance, stationary cam  2  and rotary cam  4  are held so that stationary cam  2  can move vertically, and stationary member  1  and rotary member  3  are held on shaft  6  rotatably.  
         [0031]     Next, forming method of spread portion  16 C is described.  
         [0032]     First, the upper end of cylindrical part  16 A of shaft  16  is inserted into through-hole  13 B from beneath rotary member  13  as shown in  FIG. 3A . Next, the upper end of cylindrical part  16 A is projected slightly out of the top surface of rotary member  13  as shown in  FIG. 3B , and the upper end is then depressed from above rotary member  13  by using generally conical punch (not shown), to form spread portion  16 C for caulking.  
         [0033]     As shown in  FIG. 3C , the upper end of cylindrical part  16 A is spread out and bent down radially for caulking. As through-hole  13 B is provided with at least one notch  13 A dented outward, the periphery of cylindrical part  16 A protrudes to the notch  13 A, forming at least one fixing portion  16 D on inner periphery of spread portion  16 C. As a result, the upper end of cylindrical part  16 A of shaft  16  is fixed by caulking on rotary member  13 , thereby integrating rotary member  13  with shaft  16 . That is, shaft  16  has on its first end a caulked portion, consisting of spread portion  16 C and fixing portions  16 D, to fix rotary member  13 . Fixing positions  16 D protruded into notches  13 A can limit a rotation of shaft  16  against rotary member  13 . Additionally, spread portion  16 C spread out radially on the top surface of rotary member  13  can limit rotary member  13  to move upward.  
         [0034]     Opening/closing device  20  further includes lubricating plate  17  disposed between head  16 B located at the end of shaft  16  and the bottom surface of stationary member  1  as shown in  FIG. 1 . Lubricating plate  17  is a plate having a through-hole and is produced by using mixed-nylon with carbon, nickel-plated steel or the like to have a lubricating surface. Lubricating plate  17  is requested to have a through-hole and a lubricating surface, but is not limited to have a round outline.  
         [0035]     Opening/closing device  20  with the aforementioned configuration is used for instance in cell-phones, video cameras or the like. Stationary member  1  is fixed to a stationary housing (not shown) provided with a plurality of operation parts, micro-phone or the like, and rotary member  13  is fixed to a rotary housing (not shown) provided with a display, a speaker, a camera or the like. Electronic equipment with such opening/closing device enables to open and close the rotary housing against the stationary housing.  
         [0036]      FIG. 2  illustrates a case in which cam parts  2 A and cam parts  4 A of opening/closing device  20  can engage at the angular positions of 0, 90, 180 and 270 degrees respectively in the exemplary embodiment of the present invention. The operation of opening/closing device with such configuration is described next.  
         [0037]     The condition when rotary member  13  is laid in parallel on stationary member  1  longitudinally, or when the rotary housing is closed on the stationary housing, is taken as the angular position of 0 degree. Upon turning rotary member  13  to the opening direction by turning rotary housing from the angular position of 0 degree, rotary cam  4  also rotates accordingly. After turning by 90 degrees, concave cam parts  4 A provided on the bottom surface of rotary cam  4  engage convex cam parts  2 A provided on the top surface of stationary cam  2  to hold rotary member  13  once being opened at the angular position of just 90 degrees.  
         [0038]     When turning rotary member  13  further from the angular position of 90 degrees, stationary cam  2  moves downward leaving cam parts  4 A released from cam parts  2 A to rotate rotary cam  4  also. After turning still further 90 degrees to the angular position of 180 degrees from the closed condition (0-degree), spring  5  pushes cam parts  2 A to engage cam parts  4 A and then rotary member  13  will be stopped  
         [0039]     Namely, turning rotary member  13  fixed to the rotary housing of equipment can perform to open and close the rotary housing against the stationary housing, and that the rotary housing can be held at a predetermined angular position such as 0, 90, 180 degree or the like with the movements of rotary cam  4  fixed to rotary member  13  and stationary cam  2  fixed to stationary member  1 .  
         [0040]     Setting the angular position of concave cam parts  4 A or convex cam parts  2 A in various degrees can change the holding angle between the rotary housing and stationary housing. For example, six pieces of concave cam parts  4 A disposed with the angular spacing of 60 degrees each, against the same six pieces of convex cam parts  2 A disposed with the same spacing of 60 degrees each or two pieces with the spacing of 180 degrees each can provide the rotary housing with a finer holding angle, or an opening angle.  
         [0041]     In the exemplary embodiment 1, a plurality of fixing portions  16 D are formed on inner periphery of spread portion  16 C and the upper end of cylindrical part  16 A of shaft  16  is fixed by caulking to integrate with rotary member  13 . Namely, upon turning rotary member  13 , which is fixed to shaft  16 , the opening/closing operation would cause no wear between the bottom surface of spread portion  16 C and the top surface of rotary member  13 .  
         [0042]     Moreover, lubricating plate  17  disposed between head  16 B located at the end of shaft  16  and the bottom surface of stationary member  1  can reduce the wear between head  16 B and stationary member  1 . Consequently, rotary member  13  of opening/closing device  20  can perform the opening/closing operation smoothly without irregular feeling.  
         [0043]     As described in exemplary embodiment 1, shaft  16  can be fixed to rotary member  13  by fixing the upper end of shaft  16  by caulking, which is a simple work for fixing compared with welding or the like. In addition, the opening/closing device can perform the operation smoothly and surely without irregular feeling or the like.  
         [0044]     Additionally, lubricating plate  17  disposed between the lower end of shaft  16  and stationary member  1  can prevent wear between head  16 B located at the end of shaft  16  and stationary member  1 .  
         [0045]     A method different from the description to fix the upper end of shaft  16  to rotary member  13  by caulking with reference to  FIG. 3  is described in next exemplary embodiment 2.  
         [0046]     In exemplary embodiment 2, the partial perspective view in  FIG. 4A  shows that at least one notch  16 E is provided at the upper end of cylindrical part  16 A of shaft  16 , and that at least one protrusion  13 D is provided on through-hole  13 B of rotary member  13 . The example shown in this exemplary embodiment 2 has two notches  16 E and two protrusions  13 D.  
         [0047]     Cylindrical part  16 A is inserted into through-hole  13 B from beneath rotary member  13  as shown in  FIG. 4B . And then the upper end of cylindrical part  16 A is then depressed from above by using, for instance, generally conical punch (not shown) or the like to spread out the upper end of cylindrical part  16 A, forming spread portion  16 C as shown in  FIG. 4C .  
         [0048]     In this case, protrusions  13 D of rotary member  13  fit notches  16 E of shaft  16 , thereby fixing the upper end of cylindrical part  16 A to rotary member  13  by caulking integrally. Like in exemplary embodiment 1, the fixed configuration can prevent the wear between rotary member  13  and shaft  16 . In exemplary embodiment 2, shaft  16  has spread portion  16 C engaging protrusions  13 D to act as a caulking portion. The caulking portion (or spread portion  16 C) that is spread out on the top surface of rotary member  13  also can stop rotary member  13  to move upward. In addition, the caulking portion (or spread portion  16 C) that contacts appressed at edges of protrusions  13 D can stop rotary member  13  to rotate around shaft  16 .  
         [0049]     In exemplary embodiment 1 and 2, it is described that the upper end of shaft  16  is fixed to shaft  16  by caulking and shaft  16  and rotary member  13  rotate together. Contrarily, a configuration in which rotary member  13  is held rotatably by shaft  16 , which is fixed to stationary member  1  by caulking, is also acceptable within the scope of the embodiment of the present invention.  
         [0050]     Moreover in exemplary embodiment 1 and 2, it is described that the configuration includes four components: stationary member  1 ; rotary member  13 ; stationary cam  2 ; and rotary cam  4 . However, it may be acceptable that convex stationary cams are formed integrally on the top surface of stationary member  1 , and concave rotary cams are formed integrally on the bottom surface of rotary member  13 . In addition to this, a configuration with spring  5  disposed on the bottom surface of stationary member  1  or on the top surface of rotary member  13 , to perform a resilient contact between convex stationary cams and concave rotary cams, can provide the opening/closing device with a low cost price due to a decrease in a number of parts.  
         [0051]     It will be obvious to those skilled in the art that various changes may be made in the above-described embodiments of the present invention. However, the scope on the present invention should be determined by the following claims.