Abstract:
A hinge device of a portable terminal connects a keyboard member to a comparatively massive display member and has cam and friction mechanisms. The cam mechanism has a fixing cam for axially receiving a shaft which extends into a cam case having a rotation arresting mechanism fixed on the shaft, a slider cam provided slidably in a manner to confront the fixing cam restrained in its rotation by the cam case, and an elastic mechanism for pressing the slider cam toward the fixing cam. The friction mechanism has a friction ring attached to the shaft and fitted into the friction case under pressure with a rotatable rotation arresting mechanism, so that both of automatic close lock function from a predetermined closed angle between the first and second members and a free stop function when opening and closing operation of the first and second members can be realized together without strain.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     This is a divisional of application Ser. No. 10/746,580 filed Dec. 24, 2003 which is incorporated here by reference, and which claimed priority on Japanese Patent Application No. 2002-375954 filed Dec. 26, 2002, which claim is repeated here. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to a hinge device used for a portable intelligence terminal structured with a first member composed of a keyboard main body and a second member composed of a display device, in particular, suitable for use in connecting the second member, which is comparatively massive at a portion of the display device, to the first member in a openable and closable manner relatively.  
         [0004]     2. Description of the Relevant Art  
         [0005]     Conventionally, as this kind of a hinge device, a technology disclosed in a Japanese Patent Laid-open No. 2000-337008 is well-known.  
         [0006]     A hinge device disclosed in this laid-open patent official gazette includes: a shaft having an arresting portion at an end portion; a case body having a rotation arresting means allowing the shaft to be inserted through axially at the central portion and to be arrested at an arresting portion; a slider cam slidably arrested in a key groove provided on an open end side of the case body in the axial direction and having a cam portion at one end, and at the same time, allowing the shaft to be inserted through axially at the central portion; a fixing cam having a cam portion at an end confronting to the cam portion of the slider cam and allowing the shaft to be inserted through axially at the central portion; and a compression spring rounded around the shaft, being accommodated in the case body, and installed resiliently between the case body and the slider cam.  
       SUMMARY OF THE INVENTION  
       [0007]     Since a purpose of a hinge device shown in the laid-open patent official gazette is to control an opening-and-closing operation of the display device, being the second member, to the keyboard main body, being the first member, only with a cam mechanism, there arises a disadvantage that even for a compact type portable intelligence terminal having a comparatively massive display device, being the second member, it is difficult to realize both an automatic closed lock function from a predetermined closed angle, and a free-stop function at the time of opening and closing operation with regard to the keyboard main body, being the first member, of the display device.  
         [0008]     An object of the present invention is to provide a hinge device for a portable intelligence terminal which can realize both an automatic closed lock function from a predetermined closed angle and a free-stop function at the time of opening and closing operation at the same time with a structure as simple as possible, when an opening and closing operation of a display device, which is comparatively massive second member, is conducted with regard to a keyboard main body, being the first member.  
         [0009]     In order to achieve the object described above, the present invention discloses a hinge device connecting a first member and a second member being opened and closed relatively, provided with a cam mechanism and a friction mechanism disposed on a shaft coaxially, wherein the cam mechanism includes a fixing cam provided by allowing a shaft to insert through axially at each central portion into a cam case side having a rotation arresting means fixed on the shaft, a slider cam provided slidably in a manner to confront to the fixing cam, being restrained its rotation by the cam case, and an elastic means to press the slider cam toward the fixing cam side; wherein the friction mechanism includes: a friction case having a rotation arresting means attached to the shaft in a manner to be rotatable, and a friction ring attached to the shaft and fitted in the friction case with pressure.  
         [0010]     The present invention further discloses a hinge device connecting a first member and a second member being opened and closed relatively, provided with a cam mechanism and a friction mechanism disposed on a shaft coaxially; wherein the cam mechanism includes a fixing cam provided by allowing a shaft to insert through axially at each central portion into a cam case side having a rotation 
        arresting means fixed on the shaft, a slider cam provided slidably in a manner to confront to the fixing cam, being restrained its rotation by the cam case, and an elastic means to press the slider cam toward the fixing cam side;     wherein the friction mechanism includes a flange portion provided on the shaft, a bracket attached on the shaft, a friction washer, an elastic means, and a clamping nut so that friction torque is generated there between the friction washer and one side or both sides of the bracket.        
 
         [0013]     At that time, the clamping nut can be replaced by caulking an end portion of the shaft.  
         [0014]     The present invention still further disclose a hinge device connecting a first member and a second member being opened and closed relatively, having a pair of cam mechanism disposed on a shaft coaxially on the shaft, wherein each cam mechanism includes a fixing cam provided by allowing a shaft to insert through axially at each central portion into a cam case side having a rotation arresting means fixed on the shaft, a slider cam provided slidably in a manner to confront to the fixing cam, being restrained its rotation by the cam case, and an elastic means to press the slider cam toward the fixing cam side.  
         [0015]     In any case of the invention described above, at least one portion of each cam portion provided on the fixing cam and the slider cam of each cam mechanism is formed in a plane portion so that friction torque is generated.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]      FIG. 1  is a plan view of a keyboard main body which is a first member and a display device which is a second member of a portable intelligence terminal using a hinge device relating to the present invention, both being seen in a open state;  
         [0017]      FIG. 2  is a front view of the hinge device relating to the present invention;  
         [0018]      FIG. 3  is a right side view of the hinge device shown in  FIG. 2 ;  
         [0019]      FIG. 4  is a left side view of the hinge device shown in  FIG. 2 ;  
         [0020]      FIG. 5  is a front sectional view of the hinge device shown in  FIG. 2 ;  
         [0021]      FIG. 6  is a right side view of a fixing cam of the hinge device shown in  FIG. 2 ;  
         [0022]      FIG. 7  is a front view of the fixing cam of the hinge device shown in  FIG. 2 ;  
         [0023]      FIG. 8  is a plane view of the fixing cam of the hinge device shown in  FIG. 2 ;  
         [0024]      FIG. 9  is a left side view of a slider cam of the hinge device shown in  FIG. 2 ;  
         [0025]      FIG. 10  is a right side view of the slider cam of the hinge device shown in  FIG. 2 ;  
         [0026]      FIG. 11  is a plane view of the slider cam of the hinge device shown in  FIG. 2 ;  
         [0027]      FIG. 12  is a vertical cross section of the slider cam of the hinge device shown in  FIG. 2 ;  
         [0028]      FIG. 13  is a side view of the cam guide shown in  FIG. 2 ;  
         [0029]      FIG. 14  is a vertical cross section to explain movement of the hinge device shown in  FIG. 2  to  FIG. 5 ;  
         [0030]      FIG. 15  is an explanatory view to explain movement of each cam portion;  
         [0031]      FIG. 16  is a front view showing other embodiment of the hinge device relating to the present invention;  
         [0032]      FIG. 17  is a right side view of the hinge device shown in  FIG. 16 ;  
         [0033]      FIG. 18  is a left side view of the hinge device shown in  FIG. 16 ;  
         [0034]      FIG. 19  is a vertical cross section of the hinge device shown in  FIG. 16 ;  
         [0035]      FIG. 20  is a right side view of a shaft used in the hinge device shown in  FIG. 16 ;  
         [0036]      FIG. 21  is a side view of a bracket used in the hinge device shown in  FIG. 16 ;  
         [0037]      FIG. 22  is a side view of a cam guide used in the hinge device shown in  FIG. 16 ;  
         [0038]      FIG. 23  is a left side view of a first friction washer used in the hinge device shown in  FIG. 16 ;  
         [0039]      FIG. 24  is a left side view of a second friction washer used in the hinge device shown in  FIG. 16 ;  
         [0040]      FIG. 25  is a side view of a retaining washer used in the hinge device shown in  FIG. 16 ;  
         [0041]      FIG. 26  is an explanatory view to explain operation of the hinge device shown in  FIG. 16 ;  
         [0042]      FIG. 27  is a front view showing a still another embodiment of the hinge device;  
         [0043]      FIG. 28  is a right side view of the hinge device shown in  FIG. 27 ;  
         [0044]      FIG. 29  is a left side view of the hinge device shown in  FIG. 27 ;  
         [0045]      FIG. 30  is a vertical cross section of the hinge device shown in  FIG. 27 ; and  
         [0046]      FIG. 31  is a vertical cross section to explain operation of the hinge device shown in  FIG. 27 . 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0047]     Drawings show an embodiment of the present invention. In  FIG. 1 , the one shown with a reference number  1  denotes, for instance, a portable intelligence terminal, and the one shown with a reference number  2  denotes a keyboard main body forming a first member. The one shown in a reference number  3  denotes a display device composed of, for instance, a liquid crystal display device which forms a second member.  
         [0048]     The hinge devices A and A relating to the present invention are used for connecting the keyboard main body  2 , being the first member, and the display device  3 , being the second member, so that the key board main device and the display device can open and close relatively to each other, and installed between attachment portions  2   a  and  2   a  of the keyboard main body  2  and attachment portions  3   a  and  3   a  of the display device. Though the hinge devices A and A are provided in a pair in this drawing, they can be in one piece. Since the hinge devices A and A are bilaterally symmetrical, and they are structured in the same way, the explanation thereof will be made hereinafter for a left hinge device A in  FIG. 1 .  
         [0049]     The structure of a cam mechanism  4  affected by an elastic means is as follows. Firstly, in  FIG. 2 , the one shown with a reference number  5  denotes a shaft, and a reference number  6  denotes a cam case. The cam case  6  opens at one end, having rotation arresting means  6   a  and  6   a  formed of a pair of concave grooves axially on the periphery, and a deformed attachment portion  5   a  provided at one end of the shaft  5  is allowed to insert through into a deformed attachment hole  6   c  provided on the side wall  6   b  and engaged therewith, and fixed to the shaft  5  so as to be rotated with the shaft  5  by a fixing pin  7 .  
         [0050]     On the open end side of the cam case  6 , a slider cam  8  is slidably accommodated axially, being restrained its rotation by the cam case  8 , while allowing the shaft  5  to insert through into a through hole  8   a  provided oxially at the central portion, and allowing a pair of key portions  8   b  and  8   b  provided on the outside thereof to engage with a key grooves  6   d  and  6   d  provided on the periphery of the cam case  6 . An elastic means  9  composed of a compression spring wound around the shaft  5  is disposed between the slider cam  8  and the side wall  6   b  of the cam case  6 .  
         [0051]     A fixing cam  10  is disposed at a position confronting to the slider cam  8 , allowing the shaft  5  to insert through into a through hole  10   a  provided axially at the central portion, the fixing cam  10  is locked at one side of a flange portion  11   a  of a friction ring attachment portion  11  in a friction mechanism, to be described later, which is provided on one side of the shaft  5 , and is in a state that its rotation is restricted by a cam guide  12  having a rotation arresting means  12   b  which has a flat portion on the outside thereof. A method of arresting the rotation of the fixing cam  10  at the cam guide  12  is conducted by engaging a concave groove  10   b  of the fixing cam  10  inserted into a deformed attachment hole  12   a  with a convex portion  12   c  of the deformed attachment hole  12   a  provided on the cam guide  12 , but it is not limited to this method.  
         [0052]     On the confronting faces of the slider cam  8  and the fixing cam  10 , cam portions  13  and  14  composed of convex portions  13   a  and  14   a , and concave portions  13   b  and  14   b  whose respective upper surfaces are flat, are disposed.  
         [0053]     A structure of a friction mechanism  15  is as follows. A reference number  16  denotes a friction case which has a side wall  16   a , opens at one end, and is provided with a rotation arresting means  16   b  composed of a flat portion on the outer periphery. A shaft  5  is inserted axially at the central portion of the friction case  16 , and rotatably supported in a through hole  16   c  provided on the side wall  16   a . The friction case  16  is locked at the shaft  5  by the E ring  5   c  attached to on the other end portion of the shaft so as not to be got out. In the inside of the friction case  16 , a friction torque generation hole  16   d  is provided concentrically with a through hole  16   c , and in this friction torque generation hole  16   d , three pieces of friction rings  17  made of, for instance, rubber, is press fitted to the friction ring attachment portion  11  between the flange portions  5   b ,  5   b  formed to the shaft  5 . Incidentally, though not shown, between the friction ring  17  and the friction torque generation hole  16   d , viscous lubricant oil, for instance, silicone oil, is applied.  
         [0054]     Therefore, as shown in  FIG. 1 ,  FIG. 4 , and  FIG. 14 , the cam case  6  of the hinge device A is allowed to insert through into and engage with the deformed attachment hole  3   b  provided on the attachment portion  3   a  of the display device  3 , and the friction case  16  is inserted into and locked at the deformed attachment hole  2   b  provided on the attachment portion  2   a  of the keyboard main body  2  to complete assembling to the hinge device A.  
         [0055]     As shown in  FIG. 4 , in a closed state of the display device  3 , being the second member, into the keyboard main body  2 , being the first member, the convex portion  13   d  of the cam portion  13  in the slider cam  8  is in a state of sliding down to the middle in the concave portion  14   b  of the cam portion  14  in the fixing cam  10 , as shown in  FIG. 15 . When the display device  3  being the second member, is opened in relation to the keyboard main body  2  being the first member from this state, the cam case  6  rotates together with the display device  3 . At first, the convex portion  13   a  of the cam portion  13  in the slider cam  8  rotating together with the cam case  6  meets with resistance at the time of getting out from the concave portion  14   b  of the cam portion  14  of the fixing cam  10  in the compression spring  9 , and then, as shown with a solid line and an imaginary line in FIG;  15 , the convex portions  13   a  and  14   a  of respective cam portions  13  and  14 , on the surfaces of which are flat, slide on each other in a pressure contact state. Accordingly, by friction torque generated from a pressure contact force between respective convex portions  13   a  and  14   a  of these respective cam portions  13  and  14 , and friction torque generated between an outer periphery of the friction ring  17  in the friction mechanism  15  and inner periphery of the friction torque generation hole  16   d , the display device  3  opens in a free-stop state to the keyboard main body  2 .  FIG. 14  shows a state that the display device  3  is opened at 90° with regard to the keyboard main body  2 . When exceeded an open angle of about 1100 with regard to the key board main body  2 , at which angle the display device  2  is often opened, the display device  3  is opened only with friction torque of the friction mechanism  15  by sliding down of the convex portion  13   a  of the cam portion  13  in the slider cam  8  into the concave portion  14   b  of the cam portion  14  in the fixing cam  10 .  
         [0056]     As for the case that an opened display device  3  is closed with regard to the keyboard main body  2 , when the display device  3  is opened at an angle of 110° or more, the convex portion  13   a  of the cam portion  13  in the slider cam  8  meets with some resistance at the time of getting out from the concave portion  14   b  of the cam portion  14  in the fixing cam  10 . However, from an angle of 110°, the display device  3  is closed with regard to the keyboard main body  2  in a free-stop state, due to a synergistic effect of friction torque generated from a state of pressure contact of respective convex portions  13   a  and  14   a  of respective cam portions  13  and  14  and friction torque of the friction mechanism  15  as shown in  FIG. 15  with a solid line and an imaginary line.  
         [0057]     From an angle of about 10° just before the display device  3  is closed, since the convex portion  13   a  of the cam portion  13  in the slider cam  8  slides down from the convex  14   a  of the cam portion  14  in the fixing cam  10  into the concave portion  14   b , the display device  3  is automatically closed, and locked not to open naturally in a closed state by a suction force generated at that time.  
         [0058]     Thus, the hinge device of this embodiment locks the display device  3  in a closed state with regard to the keyboard main body  2 , can open to a usage angle in a free-stop state, and at the usage angle, while the display device is kept stably, it can be closed as if it were inhaled just before closing of the display device  3  by the cam mechanism  4 . At the time of opening and closing operation of the display device  3 , a soft opening and closing feeling is given to an operator by the friction mechanism, and a buffering effect at the time of closing can be realized.  
         [0059]      FIG. 16  to  FIG. 26  show another embodiment. According to the drawings, a hinge device B relating to this embodiment is shown as a left side one in  FIG. 1 , a cam mechanism  21  and a friction mechanism  22  are provided on the left and right of a flange portion  20   a  provided approximately in the central portion of a shaft  20 . Since the structure of the cam mechanism  21  is the same as that in the previous embodiment, the explanation thereof will be omitted. The friction mechanism  22  is provided on the left side of the flange portion  20   a  of the shaft  20 , and as shown in  FIG. 21 ,  FIG. 23  to  FIG. 25 , includes a first friction washer  23 , a bracket  24 , a second friction washer  25 , a spring washer  26 , a retaining washer  27 , and a clamping nut  28  from an adjacent side of the flange portion, disposed in a manner to allow the shaft to insert through the through holes  23   a ,  24   a ,  25   a ,  26   a  and  27   a  provided axially at respective central portions. The first friction washer  23  is fixed to the shaft  20  by engaging an arresting piece  23   b  which is bent from its outer periphery with an arresting groove  20   b  provided on the flange portion  20   a . The bracket  24  is rotatable to the shaft  20 , but a rotation arresting means  24   b  formed of a flat portion is provided on the outer periphery thereof. The second friction washer  25  is structured to rotate with the bracket  24  by engaging an arresting piece  25   b  which is bent from its outer periphery with an arresting groove  24   c  provided on the outer periphery of the bracket  24 . The spring washer  26  and the retaining washer  27  are restrained their rotation by the shaft  20  by allowing respective deformed through holes  26   a  and  27   a  to insert through and engage with a deformed portion  20   c  of the shaft  20 . The clamping nut  28  is screwed on a male screw portion  20   d  of the shaft  20 , so that it is structured to generate friction torque accompanied by rotational movement of the shaft  20  by pressure contact of the first friction washer  23  to one side of the bracket  24 , and by pressure contact of the second friction washer  25  to the side face of the spring washer  26 .  
         [0060]     Therefore, a portion of the friction mechanism  22  is allowed to insert into the deformed attachment hole  2   b  provided on the attachment portion  2   a  of the keyboard main body, being the first member, the cam guide  12  and the bracket  24  are engaged with the deformed attachment hole  2   b , and then a portion of the cam case  6  is allowed to insert and lock at the deformed attachment hole  3   b  provided on the attachment portion  3   a  of the display device  3 , being the second member, thereby assembling of the hinge device B is completed.  
         [0061]      FIG. 19  shows this state in a vertical cross section. In this state, as shown in  FIG. 15  with a solid line, the convex portion  13   a  of the cam portion  13  in the slider cam  8 , inserts into the concave portion  14   b  of the cam portion  14  in the fixing cam  10  to lock the display device  3  not to open naturally with regard to the keyboard main body  2 .  
         [0062]     When the display device  3  opens with regard to the keyboard main body  2  from this closed state, since the cam case  6  rotates together with the shaft  20  and the slider cam  8  as shown in  FIG. 15  with a solid line and an imaginary line, friction torque by sliding in pressure contact of a flat convex portion  13   a  of the cam portion  13  in the slider cam  8  with a flat convex portion  14   a  of the cam portion  14  in the fixing cam  10 , and friction torque by sliding in pressure contact between the first friction torque  23  and the bracket  24 , and between the second friction washer  25  and the spring washer  26 , are generated, the display device  3  is suspended and kept stably, especially at an open angle of about 100° to 110°, which is the usage angle. It is of course possible to open further to 180°, and the friction torque at that time can be freely selected.  
         [0063]     Subsequently, when the display device  3  is closed, at about 10° which is a closed position, owing to the rotary torque generated when the convex portion  13   a  of the cam portion  13  in the slider cam  8  fits in the concave portion  14   b  of the cam portion  14  in the fixing cam  10 , the display device  3  is closed as if being inhaled and locked in a closed state.  
         [0064]     It should be noted that on which face of the first friction washer or the second friction washer should the friction torque of the friction mechanism  22  be generated can be freely selected other than that in the embodiment and the clamping nut  28  can be replaced by caulking of the end portion of the shaft  20 .  
         [0065]      FIG. 27  to  FIG. 30  show another embodiment of a hinge device C relating to the present invention. The hinge device C of the present embodiment is the one shown on the right in  FIG. 1 , and the hinge device C is provided with bilaterally symmetrical first cam mechanism  31  and a second cam mechanism  32  on both sides of the shaft, and the structure of the first cam mechanism  31  and the second cam mechanism  32  are the same as that of the cam mechanism  4  and  21  in the previous embodiment. At nearly the central portion of a shaft  30 , a pair of a first fixing cam  33  and a second fixing cam  34  allow the shaft  30  to insert through into through holes  33   a  and  34   a  provided axially at the central portion so that respective side faces are allowed into contact impactedly with each other, and a first cam guide  36  and a second cam guide  37  having rotation arresting means  36   b  and  37   b  composed of a flat portion on the outer periphery while accommodating the first fixing cam  33  and the second fixing cam  34  in the inside.  
         [0066]     On the one of both end portions of the shaft  30 , a first cam case  38  with an open end and provided with a rotation arresting means  38   a  having a concave groove on the periphery is arranged allowing the shaft  30  to insert through inside in the axial direction, and a deformed portion  30   a  provided on an end of the shaft  30  is allowed to insert into a deformed through hole  38   c  provided on a side wall  38   b  of the first cam case  38  and fixed so that the shaft  30  is arrested with a attachment pin in order not to get out.  
         [0067]     On the other end of both end portions of the shaft  30 , a second cam case  40  with an open end is arranged allowing the shaft  30  to insert through inside in the axial direction similarly, and the shaft  30  is allowed to insert into a through hole  40   b  provided on a side wall  40   a , so that the shaft  30  is arrested with a deformed flange portion  30   b  in order not to get out while the deformed flange portion  30   b  is engaged into a deformed hole.  
         [0068]     On an aperture sides in the first and second cam cases  38  and  40 , a pair of first slider cam  41  and second slider cam  42  are provided confronting to the first and second fixing cam  33  and  34 , allowing the shaft  30  to insert through into through holes  41   a  and  42   a  provided axially at the central portion, a first and second elastic means  43  and  44  allowing to wind around the shaft  30 , composed of a compression spring are disposed between respective first and second slider cams  41  and  42 , and respective side walls  38   b  and  40   a  of the first and second cam cases  38  and  40 , so that the first and second slider cams are always forced slidably toward respective first and second fixing cam sides.  
         [0069]     Respective first and second slider cams  41  and  42  are provided with a pair of first and second key portions  41   b  and  42   b  on the outer periphery, the shaft  30  can be slide in the axial direction by engaging respective first and second key portions  41   b  and  42   b  with a first and second key grooves  38   d  and  40   c  provided in the cam cases  38  and  40 .  
         [0070]     On confronting surfaces of respective first and second fixing cams  33 ,  34  and respective first and second slider cams  41  and  42 , first and second cam portions  45  and  46  composed of convex portions  45   a ,  45   a  and  46   a ,  46   a  and concave portions  45   b ,  45   b  and  46   b ,  46   b  similarly to the above-described respective embodiment are provided.  
         [0071]     Accordingly, as shown in  FIG. 27 ,  FIG. 28  and  FIG. 30 , by allowing the first cam case  38  to insert into and lock at the deformed attachment hole  3   b  provided on the attachment portion  3   a  of the display device  3 , being the second member, and by allowing the second cam case  40  and the first and second cam guides  36 ,  37  to insert into and lock at the deformed attachment hole  2   b  provided on the attachment portion  2   a  of the keyboard main body  2 , being the first member, the assembling is completed.  
         [0072]     When the display device  3  is opened and closed with the regard to the keyboard main body, the first cam case  38  rotates together with the shaft  30  and the first slider cam  41 , and the second cam case  40  rotates together with the shaft  30  and the second slider cam  42 . Then, since respective first and second convex portions  45   a  and  46   a  of respective first and second cam portions  45  and  46  in the closed state of the display device  3  are separated from first and second concave portions  45   b  and  46   b  of respective first and second fixing cam  34  and rotate in a pressure contact state with respective flat first and second convex portions  45   a  and  46   a  of respective first and second cam portions  45  and  46  in respective first and second fixing cam  33  and  34 , friction torque is generated, respective first and second slider cam  41  and  42  can stably suspend the display device  3  especially at an open angle about 100° which is its usage angle. It is of course possible here to open the display device to 180° with regard to the keyboard main body  2 . It is possible to select the friction torque at that time at will by arbitrary selecting the shapes of respective first and second cam portions  45  and  46 .  
         [0073]     When the display device  3  is closed with regard to the keyboard main body  2 , at just before its closed position (for instance about 10°), since respective first and second convex portions  45   a  and  46  of respective first and second cam portions  45  and  46  in the first and second slider cams  41  and  42  are forced to rotate in the closed direction when they slide down into respective first and second concave portions  45   b  and  46   b  of respective first and second cam portions  45  and  46  in respective first and second fixing cam  33  and  34 , the display device  3  is closed as if being inhaled naturally even taking the hand off. And in this closed state, the display device  3  is locked to prevent itself from opening naturally after closed.  
         [0074]     It should be noted that, as another embodiment, the cam case  6  and the cam case  38  can be attached to the attachment portion  2   a  on the keyboard main body  2  side, being the first member, and each of the rotation arresting means provided on the outside and inside of the cam cases  6 ,  38 , on the outside of the friction case  16 , and respective outsides of the fixing cam  10 , the slider cams  8 ,  13 , and the cam guides  12 ,  36  and  37  is not limited to the above-described embodiments. It is also acceptable to be structured that the flange portion of the shaft is provided in the opposite direction from that in the above-described embodiments so that the cam cases  6  and  38  are locked with E rings. Further, the shapes of deformed portions, deformed attachment portions, and deformed through holes of respective shafts of the fixing cams and the fixing members are not limited to those in the embodiments, they can be formed in various well-known shapes. As for materials used in the shaft, respective cases, the fixing cams, the fixing members and slider cams are not limited to that in the embodiment, material such as SUS, POM, and the like can be used as necessary, though for materials for the shafts, the fixing cams, and the slider cams, it is desirable to use hard material made of metal because strength and abrasion resistance are required.