Abstract:
A lock unit used for an electronic apparatus that includes a foldable and unfoldable housing that has a first surface that is foldable, and a second surface orthogonal to the first surface includes a lock member that locks the housing in a folded state, an operation member that moves the lock member and releases a lock of the housing by the lock member, and a transmission mechanism that transmits a driving force applied to the operation member to the lock member by changing an operating direction of the operation member to another direction, and moves the lock member in the other direction, wherein the operation member is provided on the second surface, and an operating direction of the operation member is a first direction perpendicular to the second surface, the lock member projecting in a second direction orthogonal to the first surface, and a moving direction of the lock member being a third direction orthogonal to the first and second directions.

Description:
This application is a continuation based on International Patent Applications Nos. PCT/JP2005/007317, filed on Apr. 15, 2005, and PCT/JP2006/305665, filed on Mar. 22, 2006, each of which is hereby incorporated by reference herein in its entirety as if fully set forth herein. This application is a divisional application of U.S. patent application Ser. No. 11/907,614 filed Oct. 15, 2007, now allowed and incorporated by reference herein. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates generally to an electronic apparatus, and more particularly to a lock/unlock unit of a foldable housing of the electronic apparatus. The “electronic apparatus,” as used herein, intends to cover, for example, a laptop personal computer (“PC”), a personal digital assistant (“PDA”), an electronic dictionary, electronic stationery, and a game machine. The present invention is suitable, for example, for a lock/unlock unit (simply referred to as a “lock unit” hereinafter”) used for the laptop PC. 
     Due to the recent spreads of PCs, laptop PCs are increasingly required to be easier to use. The typical laptop PC&#39;s housing includes a display unit (upper housing) equipped with a liquid crystal display (“LCD”) screen, and a body (lower housing) over which the display unit is foldable and from which the display unit is unfoldable. The display unit typically has a hook and an operation member, and the body has an engagement hole. In folding the housing, the display unit is rotated toward the body, and the housing is locked in the folded state when the hook is engaged with the body through the engagement hole. In unfolding the housing, the operation member is operated to move the hook and to release the lock, and then the display unit is rotated in a direction separating from the body. Due to the recent widespread uses of PCs to watch TV broadcasting and DVD movies, many users enjoy images on a high-quality, wide display screen, a smaller lock unit to secure the LCD screen space has been increasingly demanded. 
       FIG. 21  shows the conventional lock unit  10  in a lock state. The lock unit  10  includes an operation button  12  provided on a display unit  11 , a hook  13  coupled with the operation button  12 , a forcing member  14 , such as a compression spring, provided in the display unit  11 , and an engagement hole  16  provided in the body  15 . The forcing member  14  forces the operation button  12  and the hook  13  in the A direction. Therefore, the hook  13  is engaged with the body  15  once inserted into the engagement hole  16 . As a result, the display unit  11  is locked up on the body  15 . In this state, when the operation button  12  is pressed, the operation button  12  moves with the hook  13  in the B direction and the hook  13  is disengaged from the body  15 . As a result, the display unit  11  is unlocked and becomes unfoldable. Thereafter, a user opens the display unit  11  by at least a predetermined angle while pressing the operation button  12 . As a result, the hook  13  is spaced from the engagement hole  16 . Once the hook  13  escapes from the engagement hole  16 , the user continues to push the operation button  12  upwardly or holds the top of the display unit  11  to rotate it upwardly, unfolding the display unit  11  from the body  15 . 
       FIG. 22  shows another example of the conventional lock unit  20 . The lock unit  20  includes an operation button  22  provided on a display unit  21 , a hook  23  fixed onto the operation button  22 , a forcing member  24 , such as a compression spring, provided on the display unit  21 , and an engagement hole  26  provided in the body  25 . The forcing member  24  forces the operation button  22  and the hook  23  in a C direction. Therefore, the hook  23  is engaged with the body  25  once inserted into the engagement hole  26 . As a result, the display unit  21  is locked onto the body  25 . In this state, when the operation button  22  with the hook  23  is slid in a D direction, the hook  23  is disengaged from the body  25  and the display unit  21  is unlocked and becomes unfoldable. Thereafter, a user opens the display unit  21  by at least a predetermined angle while pressing the operation button  22 . As a result, the hook  23  is spaced from the engagement hole  26 . Once the hook  23  escapes from the engagement hole  26 , the user continues to push the operation button  22  upwardly or holds the top of the display unit  21  to rotate it upwardly, unfolding the display unit  21  from the body  25 . 
     The conventional lock units  10  and  20  for the laptop PC are not so easy to use. Firstly, the lock unit  10  requires a width of each of the display unit  11  and the body  15  to secure a moving range of the hook  13  or the length of the engagement hole  16 , and prevents an effective utilization of the housing space. As a result, demands for a miniaturization of the entire apparatus and a wide screen display unit cannot be met unfavorably. The lock unit  20  solves this problem but the unfolding direction of the display unit  21  is perpendicular to the D direction in which the operation button  22  is moved. Therefore, in unfolding the folded housing, the user needs to execute two actions, such as a movement of the operation button  22  in the lateral direction, and then an upward rotation of the display unit, deteriorating the operability. 
     BRIEF SUMMARY OF THE INVENTION 
     Accordingly, it is an illustrative object of the present invention to provide a lock unit and an electronic apparatus having the same, which can effectively utilize the housing space and improve the operability. 
     A lock unit according to one aspect of the present invention used for an electronic apparatus that includes a foldable and unfoldable housing, the housing having a first surface that is foldable, and a second surface orthogonal to the first surface includes a lock member that locks the housing in a folded state, an operation member that moves the lock member and releases a lock of the housing by the lock member, and a transmission mechanism that transmits a driving force applied to the operation member to the lock member by changing an operating direction of the operation member to another direction, and moves the lock member in the other direction, wherein the operation member is provided on the second surface, and an operating direction of the operation member is a first direction perpendicular to the second surface, the lock member projecting in a second direction orthogonal to the first surface, and a moving direction of the lock member being a third direction orthogonal to the first and second directions. 
     In the conventional lock unit  10 , the moving direction of the operation button  12  is the same as that of the hook  13 . In the conventional lock unit  20 , the moving direction of the operation button  22  is the same as that of the hook  23 . Therefore, either the effective utilization of the housing space and or operability in the opening and closing actions is sacrificed. On the other hand, the lock unit of the present invention solves this problem because the operating direction of the operation member is different from the moving direction of the lock member due to the transmission mechanism. In one embodiment, the operating direction of the operation member is orthogonal to the moving direction of the lock member, whereas the present invention intends to cover one of them inclines to the other, and one of them is a line and the other is a rotation. In unfolding the housing, both an action to move forward the operation member, and an action to subsequently lift the housing are necessary. However, these actions do not significantly change the hand position, and the user feels as if one action can unfold the housing. Therefore, the manipulation of the operation member and unfolding of the housing can be performed continuously, and the operability improves. On the other hand, in the conventional lock unit, the lateral movement of the operation button  22  is greatly different from the lifting action of the housing. Therefore, the user feels as if two actions unfold the housing, and the operability is bad. 
     The housing may include a first housing unit that moves in folding and unfolding time, and a second housing unit that is coupled with the first housing unit, the operation member and the lock member being provided in the first housing unit. The present invention is suitable to a structure that smoothens unlocking and unfolding of the housing when the operation member and the lock member are provided onto the first housing unit that moves relative to the second housing unit. The transmission mechanism may include a projection fixed onto one of the lock member and the operation member, and a guide member that is provided on the other of the lock member and the operation member, and guides a movement of the projection, a guidance direction of the guide member inclining to a moving direction of the lock member. The guide member may have a guide groove that extends in a direction of 45° to the moving direction of the lock member. Alternatively, transmission mechanism may include a first bevel plane provided on the operation member, and a second bevel plane that is provided on the lock member, and can operably contact the first bevel plane. In this case, one of the first and second bevel planes may have a projection, and the first and second bevel planes may contact each other via the projection. Each of the first and second bevel planes may extend in a direction of 45° to the moving direction of the lock member. 
     The lock unit may further include a guide member that guides a movement of the operation member or the lock member. Thereby, the unstableness can be prevented when the operation member and the lock member move. 
     The lock unit may further include a first guide member that guides a movement of the operation member, and has a first guide groove that extends in the operating direction of the operation member and a restricting member that is fixed onto the housing and inserted into the first guide groove, and a second guide member that guides a movement of the lock member, and has a second guide groove that extends in the moving direction of the lock member and the restricting member that is fixed into the housing and inserted into the second guide groove. The restricting member, such as a rod, is commonly used for both first and second guide members, reducing the number of components, and preventing the unstableness. 
     The lock unit may further include a first engagement member that extends in a direction approximately perpendicular to the moving direction of the lock member, and is coupled with the lock member, a second engagement member that extends in the direction approximately perpendicular to the moving direction of the lock member, and is fixed onto the housing, a rod that having one end that is fixed onto the first engagement part, and the other end that penetrates through the second engagement part, the rod extending in the moving direction of the lock member, and a forcing mechanism, such as a compression spring, that is provided around the rod, and has one end that contacts the first engagement part, and the other end that contacts the second engagement part. The rod serves to hold the forcing member and to guide a movement of the lock member, effectively utilizing the housing space. 
     The lock member may be movable between a lock position used to lock the housing and an unlock position used to unlock the housing, wherein the operation member is movable between a non-operating position that allows the lock by the lock member and an operating position that releases the lock by the lock member, and wherein the lock unit further comprising a forcing member that forces the lock member towards the lock position, and the operation member towards the non-operating position. One forcing mechanism serves two forcing functions, and contributes to effectively utilize the housing space. 
     An electronic apparatus, such as a laptop PC, having the above lock unit also constitutes one aspect of the present invention. 
     Other objects and further features of the present invention will become readily apparent from the following description of preferred embodiments with reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective overview of an electronic apparatus (laptop PC) in an unfolded state according to a first embodiment of the present invention. 
         FIG. 2  is a perspective overview of the electronic apparatus in a folded state shown in  FIG. 1 . 
         FIG. 3  is an exploded perspective view of a lock unit according to the first embodiment applicable to the electronic apparatus shown in  FIG. 1 . 
         FIG. 4  is a plane view of the electronic apparatus shown in  FIG. 1  in which a rear cover is detached from a display unit. 
         FIG. 5  is a top view of the electronic apparatus shown in  FIG. 4 . 
         FIG. 6  is an exploded perspective view of the lock unit and part of the display unit in the electronic apparatus shown in  FIG. 1 . 
         FIG. 7  is an enlarged exploded perspective view of the lock unit shown in  FIG. 6 . 
         FIG. 8  is a plane view of the electronic apparatus shown in  FIG. 2  in the lock state. 
         FIG. 9A  is a MM sectional view of  FIG. 8  in the lock state, and  FIG. 9B  is an enlarged sectional view of A1 part in  FIG. 9A . 
         FIG. 10A  is a MM sectional view of  FIG. 8  in the unlock state, and  FIG. 10B  is an enlarged sectional view of A2 part in  FIG. 10A  in the unlock state. 
         FIG. 11  is a perspective overview of the electronic apparatus (laptop PC) in an unfolded state according to a second embodiment according to the present invention. 
         FIG. 12  is a perspective overview of the electronic apparatus shown in  FIG. 11  in a folded state. 
         FIG. 13  is an exploded perspective view of a lock unit according to the second embodiment applicable to the electronic apparatus shown in  FIG. 11 . 
         FIG. 14  is a plane view of the electronic apparatus shown in  FIG. 11  in which the rear cover is detached from the display unit. 
         FIG. 15  is a top view of the electronic apparatus shown in  FIG. 14 . 
         FIG. 16  is a perspective overview of the lock unit and part of the display unit in the electronic apparatus shown in  FIG. 11 . 
         FIG. 17  is an enlarged exploded perspective view of the lock unit shown in  FIG. 16 . 
         FIG. 18  is a plane view of the electronic apparatus shown in  FIG. 12  in the lock state. 
         FIG. 19A  is an NN sectional view of  FIG. 18  in the lock state,  FIG. 19B  is an enlarged sectional view of A3 part in  FIG. 19A  in the lock state, and  FIG. 19C  is an enlarged plane view of the inside of the lock unit in the lock state. 
         FIG. 20A  is the NN sectional view of  FIG. 18  in the unlock state,  FIG. 20B  is an enlarged sectional view of an A4 part in  FIG. 20A  in the unlock state, and  FIG. 20C  is an enlarged plane view of the inside of the lock unit in the unlock state. 
         FIG. 21  is a schematic sectional view of a conventional lock unit. 
         FIG. 22  is a schematic sectional view of another conventional lock unit. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the accompanying drawings, a description will be given of an electronic apparatus  100  according to a first embodiment of the present invention, which is implemented as a laptop PC. Here,  FIG. 1  is a perspective overview of the laptop PC  100  in the unfolded state.  FIG. 2  is a perspective overview of the laptop PC  100  in the folded state. Referring to  FIG. 1 , the electronic apparatus  100  is illustratively implemented as, but not limited to, the laptop PC  100 . The electronic apparatus  100  may be another portable electronic apparatus, such as a PDA, hand-held PC, a palm-sized PC, a wearable PC, an electronic dictionary, electronic stationery, a gaming machine, and a portable household appliance (e.g., a portable TV, a portable VCR, and a portable DVD). The size of the laptop PC  100  intends to cover an A4 size, a B5 size, another sub-notebook size, and a mini-notebook size. 
     The laptop PC includes a PC body  110 , a hinge  120 , a display unit (LCD bezel frame)  130 , and a lock unit  140 . The body  110  and the display unit  130  constitute a housing of the laptop PC  100 . 
     The body  110  has a housing structure, for example, with a thickness between about 20 mm and about 30 mm. The body  110  includes an upper cover  111 , a middle cover (not shown), and a lower cover  118 . Each of the upper cover  111 , a middle cover, and a lower cover  118  is made of resin molding. The body  110  accommodates a circuit board and an HDD, and the upper cover  111  has a keyboard  112  for information typing, a pointing device  114 , and an engagement hole  116 . 
     The upper cover  111  is a palm rest on which palms or wrists are placed, and is located in front of the keyboard  112 . A surface of the upper cover  111  is a surface to be folded in the laptop PC  100 . As described later, a back surface of the upper cover  111  is engaged with a hook  174 . 
     A type of the keyboard  112  is not limited, such as  101 ,  106 ,  109 , ergonomic, and the keyboard arrangement is not also limited, such as QWERT, DVORAK, JIS, new-JIS, and NICOLA (NIhongo Nyuryoku COnthotium LAyout). 
     The pointing device  14  emulates part of a mouse function, and has a touch-pad  114   a , a pair of click buttons  114   b , and a roll-type scroll wheel  114   c . The touch pad  114   a  realizes the mouse function on the LCD screen  132  when the user moves his index finger on the touch pad  114   a . The pair of click buttons  114   b  serve as mouse&#39;s left and right click buttons. Since the roll-type scroll wheel  114   c  is located between the left and right click buttons  114   b  and serves as a mouse&#39;s scroll wheel, the operability of the device  114  improves. 
     The engagement hole  116  is a hole into which the hook  174  is inserted, as described later. 
     The hinge part  120  has a hinge cover and a shaft. The hinge part  120  connects the display unit  130  with the body  110  so that the display unit  130  can rotate around the body  110 . The hinge cover is mounted with a power button, but this arrangement is merely illustrative. 
     The display unit  130  includes a front cover  131 , an LCD screen  132 , and a back cover  133 . The front cover  131  and the back cover  133  are fixed and coupled with each other via plural screw holes  134  shown in  FIG. 4 , and the LCD screen  132  is arranged between them.  FIG. 4  is a plane view of the display unit  130  with the rear cover detached.  FIG. 5  is a top view of the display unit  130  shown in  FIG. 4 . 
     The front cover  131  is a hollow rectangular frame made of resin molding, and is connected to a hinge cover on the center bottom. The back cover  133  has a substantially rectangular shape when viewed from its front, and has a sectionally U-shape in which both sides rise. The back cover  133  is connected to the hinge cover at its center bottom, and made of resin molding. 
     The lock unit  140  locks and unlocks the display unit  130  that has been folded over the body  110 . The lock unit  140  includes, as shown in  FIG. 3 , a top plate  150 , an operation member  160 , a lock member  170 , a base  180 , and a forcing member  190 .  FIG. 3  is an exploded perspective view of the lock unit  140 . Illustratively, the lock unit  140  of this embodiment is arranged on the center top of the display unit  130 . 
     The top plate  150  seals the lock unit  140 , and guides a movement of an operation button  162  of the operation member  160 . The top plate  150  includes a base  151 , a pair of attachment holes  152 , and a guide groove  153  and is made, for example, of ABS resin. 
     The base  151  is a plate lid member, and seals the lock unit  140  in cooperation with the base  180 . The base  151  has a pair of perforating attachment holes  152  at both ends, and has the guide groove  153  in its back surface. A pair of rods  183  of the base  180  is inserted into a pair of attachment holes  152 . As a result, the top plate  150  is fixed onto the base  180 . The guide groove  153  extends in an L direction perpendicular to a front surface  135  of the display unit  130  shown in  FIG. 2 . The guide groove  153  is engaged with a projection part  166  of the operation member  160 . Alternatively, the base  151  may have a projection part and the operation member  160  may have a guide groove. The number of the guide grooves and the number of projection parts are not limited. An arrangement of each of the guide groove and the projection part is not also limited. For example, a pair of projection may be provided at both side surfaces of a guide part  164  of the operation member  160 , and a pair of grooves may be provided that extend in the L direction in the pair of sidewalls  155  that bend from both ends of the top plate  150  downwardly. A guidance operation between the guide groove  153  and the projection part  166  prevents unsteadiness when the operation member  160  is moving. 
     The operation member  160  moves the lock part  170 , and serves to unlock the folded housing that has been locked by the lock part  170 . The operation member  160  can move in the L direction. The operation member  160  includes an operation button  162 , a guide member  164 , the projection part  166 , and a pair of guide grooves  168  and is made, for example, of ABS resin. 
     The operation button  162  serves as a release button onto which a compressive force is applied by a user in the unlock time. The operation button  162  projects to the front from the front surface  135  of the display unit  130 , as shown in  FIGS. 2 ,  4 , and  8 . In addition, the operation button  162  of this embodiment is illustratively flat. 
     The guide member  164  is integrated with the operation button  162 , and exhibits two guiding functions. The first guiding function is a guidance of a movement of the operation member  160  in the L direction in cooperation with the top plate  150 . In order to exhibit this function, the guide member  164  has the projection part  166  at its center, which extends in the L direction. The second guiding function is a moving function of the hook  174  of the lock member  170  in a W 2  direction by converting a direction of the driving force applied to the operation button  162  in the L 2  direction into the W 2  direction in cooperation with a pair of projections  173  of the lock member  170 , and transmitting the converted driving force to the hook  174 . For this function, the guide member  164  has a pair of guide grooves  168  engaged with a pair of projections  173 . Each guide groove  168  is configured to have the same angle θ of 45° to the W direction. As the angle θ increases, the operation button  162  is likely to move but the moving amount of the hook  174  becomes small. In order to secure the same moving amount, the moving amount of the operation button  162  in the L 2  direction becomes large. As the angle θ decreases, the moving amount of the hook  174  becomes large and a smaller moving amount of the operation button  162  in the L 2  direction is enough for the same moving amount. However, the operation button  162  becomes hard to move. Setting the angle θ to 45° can properly maintain the movement easiness and moving amount of the operation button  162 , and the moving amount of the hook  174 . 
     While this embodiment provides the guide groove  168  in the guide member  164  and the projection  173  on the lock member  170 , the guide member  164  may have a projection part and the lock member may have a guide groove. 
     According to this embodiment, the guide member  164  converts a direction of the driving force applied to the operation button  162  in the L 2  direction and transmits the converted driving force to the hook  174  of the lock member  170 , but this embodiment does not limit the driving-force direction or a conversion direction. When the driving-force direction is the L 2  direction, a hand position seldom changes when the driving force transfers to the rotating direction (R 2  direction) to open the display unit  130  in  FIG. 2 . Therefore, the user feels as if one action can unfold the housing. A H 2  or C 1  direction is, for example, a conceivable driving-force direction which achieves the opening action of the display unit  130  without greatly changing the user&#39;s hand position. In other words, in  FIG. 2 , the present invention is applicable when the operation button  162  is displaced in the upper direction (H 2  direction) or rotated counterclockwise (C 1  direction), and then the display unit  130  is opened in the R 2  direction. A moving direction of the hook  174  is not limited as long as the hook  174  is disengaged from the upper cover  111 . Therefore, for example, the hook  174  may rotate around the projection part  166  in  FIG. 3 . 
     The lock member  170  serves to lock the housing in the folded state, and can move the housing in the W direction. The lock member  170  includes a base  171 , a pair of sidewalls  172   a  and  172   b , the pair of projections  173 , a hook  174 , a shaft  175 , and a guide groove  176  and is made, for example, of polyacetal. 
     The base  171  is a plate member that is movable in the W direction. A pair of sidewalls  172   a  and  172   b  extends upwardly from both ends of the base  171 , and the forcing member  190  forces the sidewall  172   b . As a result, the hook  174  is forced in the W 1  direction. 
     A pair of projections  173  are provided on the surface of the base  171 , and engaged with the pair of guide grooves  168 . As discussed above, the projections  173  constitute part of the transmission mechanism that changes the direction of the driving force applied to the operation button  162 . 
     The hook  174  is a hook member that is engageable with the back surface of the upper cover  111  and serves to lock the housing in the folded state. The hook  174  projects from the back surface of the base  171 , and is movable with the base  171  in the W direction. The hook  174  is inserted into a perforation hole  185 , and its movement in the W direction is restricted. The end of the perforation hole  185  in the W 1  direction is a lock position at which the hook  174  is engaged with the back surface of the upper cover  111 , and the end of the perforation hole  185  in the W 2  direction is an unlock position at which the hook  174  is disengaged from the back surface of the upper cover  111 . The base  171  has a notch  177  as shown in  FIG. 7 , and the hook  174  is housed in the notch  177 .  FIG. 7  is an enlarged exploded perspective view of  FIG. 6 , and  FIG. 6  is an exploded perspective view of the lock unit  140  and part of the display unit  130 . 
     The shaft  175  supports the compression spring  190  that serves as a forcing member, and serves to guide a movement of the lock member  170  in the W direction. The shaft  175  serves to hold the forcing member and to guide a movement of the lock member  170 , effectively utilizing the housing space. The shaft  175  is a rod, one end of which is fixed onto the sidewall  172   b , and extends in the W 2  direction. The other end of the shaft  175  is engaged with an engagement groove  182  of a holder  181   b  of the base  180  shown in  FIG. 3 . The forcing member is not limited to the compression spring, and may be another member, such as cylindrical rubber, as long as it satisfies the function in the present invention. 
     The guide groove  176  serves to guide a movement of the lock member  170  in the W direction in cooperation with a rail  184  of the base  180 . The guide groove  176  is formed on the bottom surface of the base  171 . A guidance operation between the guide groove  176  and the rail  184  would prevent unstableness when the lock member  170  is moving in the W direction. 
     The base  180  serves to accommodate each part of the lock unit  140  in cooperation with the top plate  150 , and to guide and restrict a movement of the lock member  170 . The base  180  includes a pair of holders  181   a  and  181   b , a pair of projections  183 , a rail  184 , a perforation hole  185 , and a support member  186 . The base  180  is made, for example, a blend of polycarbonate and ABS resin, and integrated with the back surface of the front cover  131  of the display unit  130 . 
     A pair of holders  181   a  and  181   b  each has a U shape, defines an outline of the lock unit  140 , and holds the top plate  150 . The holder  181   a  contacts the sidewall  172   a , and restricts its movement. The holder  181   b  has an engagement groove  182  that supports the shaft  175 . The inside of the sidewall having the engagement groove  182  of the holder  181   b  contacts the end  190   b  of the forcing member  190 . A pair of rods  183  is formed at one corner of the holders  181   a  and  181   b . A pair of rods  183  is inserted into the pair of attachment holes  152  of the top plate  150 . The rail  184  extends in the W direction, and is engaged with the guide groove  176 . The hook  174  is inserted into the perforation hole  185 . The support member  186  supports the operation button  162 . 
     The forcing member  190  serves as a forcing member that forces the hook  174  towards the lock position, and as a forcing member that forces the operating member  160  to the projection position. One forcing member  190  serves two forcing functions, and contributes to the effective utilization of the housing space. The forcing member  190  includes a compression spring, and is penetrated by the shaft  175 . One end  190   a  of the forcing member  190  contacts the sidewall  172   b , and the other end  190   b  contacts the inside of the sidewall having the engagement groove  182  of the holder  181 . As a result of that the forcing member  190  forces the lock member  170  in the W 1  direction, the hook  174  is forced to the lock position. A direction of the force which the forcing member  190  applies to the lock member  170  is converted by the guide member  164 , and transmitted to the operation member  160 . As a consequence, the operation member  160  projects in the L 1  direction. 
     Referring now to  FIGS. 8-10 , a description will be given of opening and closing actions of the housing. Here,  FIG. 8  is a top view of the laptop PC  100  in the lock state.  FIG. 9A  is a MM sectional view of  FIG. 8  in the lock state, and  FIG. 9B  is an enlarged sectional view of A1 part in  FIG. 9A  in the lock state.  FIG. 10A  is the MM sectional view of  FIG. 8  in the unlock state, and  FIG. 10B  is an enlarged sectional view of A2 part of  FIG. 10A  in the unlock state. 
     In the lock state shown in  FIGS. 8 ,  9 A, and  9 B, each projection  173  is located in the back ends of the guide groove  168  in  FIG. 3  due to the force by the forcing member  190 . As a result, the operation button  162  projects from the housing in the L 1  direction, and the hook  174  is located in the perforation hole  185  at an end in the W 1  direction, and contacts the back surface of the upper cover  111  as shown in  FIG. 9B . In the lock state, due to the engagement between the hook  174  and the upper cover  111 , the display unit  130  cannot be unfolded. 
     Next, the user presses the operation button  162  shown in  FIG. 3  in the L 2  direction. When the operation member  160  moves in the L 2  direction due to the engagement between the projection member  166  and the guide groove  153 , each projection  173  moves to the front end in the guide groove  168 . As a result, the lock member  170  moves in the W 2  direction against the force of the forcing member  190  until the hook  174  moves to the end in the perforation hole  185  in the W 2  direction. 
     In the unlock state shown in  FIGS. 10A and 10B , each projection  173  is located at the front end in the guide groove  168 . The operation button  162  retreats to the end in the L 2  direction, and the hook  174  is located at the end in the perforation hole  185  in the W 2  direction and spaced from the back surface of the upper cover  111  as shown in  FIG. 10B . In the unlock state, the hook  174  is not engaged with the upper cover  111 . Therefore, the display unit  130  can be lifted upwardly (in the R 2  direction). 
     After the display unit  130  is unfolded to some extent or a desired angle, the user releases the compression to the operation button  162 . As a result, the projections  173  move from the front side to the backside in and along the guide grooves  168  of  FIG. 3  due to the force by the forcing member  190 . Therefore, the operation button  162  projects in the L 1  direction, and moves to the lock position in the W 1  direction. Thereafter, the user inputs necessary information using the keyboard  112  and the pointing device  114 . 
     According to the conventional lock unit  20 , in laterally sliding the operation button  22 , the whole hand must laterally move and then lift the display unit  21  upwardly while maintaining the lateral force. Therefore, the user feels two actions in unfolding the housing, and a bad operability. 
     On the other hand, according to this embodiment in unfolding the housing, for example, the right palm contacts the front surface  135  and lifts the display unit  130  upwardly (in the R 2  direction) while a right thumb, for example, presses the operation button  162  of the operation member  160  in the L 2  direction. However, this action does not change the hand position except for pressing by the thumb. In addition, it is easy to move the entire hand upwardly while maintaining a press by the thumb. Therefore, the user feels as if one action unfolds the housing. Due to the continuous action from manipulating of the operation member  160  to unfolding of the housing, the operability improves in comparison with the conventional one. 
     After the information is input, the display unit  130  is folded in the R 1  direction in  FIG. 2 . In that case, the user pressing the operation button  162 , and closing the display unit  130 , like a reverse action to the above opening action. However, even if the user closes the display unit  130  without touching the operation button  162 , the hook  174  is forced in the W 2  direction when contacting the surface of the upper cover  111 . As a result, the hook  174  is inserted into the engagement hole  116  and then contacts the back surface of the upper cover  111  as shown in  FIG. 9B . Therefore, it is optional to press the operation button  162  in folding the housing. 
     According to the laptop PC  100 , the lock unit can be configured in a smaller space. In addition, its operability improves because the display unit  130  is pressed upwardly (in the R 2  direction) while the operation button  162  is pressed in the L 2  direction. 
     Referring now to  FIGS. 11 to 20 , a description will be given of an electronic apparatus  100 A according to a second embodiment of the present invention, which is implemented as a laptop PC. Here,  FIG. 11  is a perspective overview of the laptop PC  100 A in the unfolded state.  FIG. 12  is a perspective overview of the laptop PC  100 A in the folded state.  FIG. 14  is a plane view of the display unit  130  from which the rear cover is detached.  FIG. 15  is a top view of the display unit  130  shown in  FIG. 14 . 
     Referring to  FIG. 11 , details of the laptop PC  100 A are different from those of the laptop PC  100 , but their basic structures are similar. Therefore, those elements in  FIGS. 11-20 , which are corresponding elements in  FIGS. 1-10 , are designated by the same reference numerals, and a description thereof will be omitted. The laptop PC  100 A is different from the laptop PC  100  in that the laptop PC  100 A includes a lock unit  200  instead of the lock unit  140 . 
     The lock unit  200  locks and unlocks the display unit  130  that has been folded over the body  110 . The lock unit  200  includes, as shown in  FIG. 13 , a top plate  210 , an operation member  220 , a lock member  230 , a base  240 , and a forcing member  250 .  FIG. 13  is an exploded perspective view of the lock unit  200  when viewed from the top. Illustratively, the lock unit  200  of this embodiment is arranged on the center top of the display unit  130 . 
     The top plate  210  seals the lock unit  200 , but unlike the top plate  150 , the top plate  210  does not guide a movement of an operation button  221  of the operation member  220 . The top plate  210  includes a base  211 , two pairs of attachment holes  212  and  217 , a chamfer  215 , and a pair of support members  216  and is made, for example, of ABS resin. 
     The base  211  is a plate lid member, and seals the lock unit  200  in cooperation with the base  240 . The base  211  has a pair of perforating attachment holes  212  at two back corners and a pair of perforating attachment holes  217  at its front side, but has no guide groove in its back surface as shown in  FIG. 17 .  FIG. 17  is an enlarged exploded perspective view of the lock apparatus  200  when viewed from the bottom, enlarging part of  FIG. 16 .  FIG. 16  is an exploded perspective view of the lock unit  200  and part of the display unit  130 . A pair of rods  243  of the base  240  is inserted into the pair of attachment holes  212 . In addition, a tip  247   b  of a pair of rod  247  of the base  240  is inserted into a pair of attachment holes  217 . As a result, the top plate  210  is fixed onto the base  240 . The chamfer  215  chamfers the top and front surfaces of the base  211  so that the user&#39;s finger that presses the operation button  221  does not contact the corner of the base  211 , improving the operability. A pair of support members  216  is provided around a pair of attachment holes  217 , and each equipped with a cap (not shown). The cap prevents exposure of a tip  247   b  of the rod  247  from the attachment hole  217 . 
     The operation member  220  moves the lock part  230 , and serves to unlock the folded housing that has been locked by the lock part  230 . The operation member  220  can move in the L direction. The operation member  220  includes an operation button  221 , a pair of projection parts  222  and  223 , a pair of guide grooves  224 , and a central groove  226  and is made, for example, of ABS resin. 
     The operation button  221  serves as a release button onto which a compressive force is applied by a user in the unlock time. In this embodiment, the operation button  221  projects to the front from the front surface  135  of the display unit  130 , as shown in  FIGS. 12 ,  14 , and  18 . In addition, the operation button  221  of this embodiment is illustratively flat. 
     The projection part  222  projects from a left side of the operation member  220  in the W 1  direction. The projection part  222  has a bevel plane  222   a . The bevel plane  222   a  is approximately parallel to the bevel plane  223   a , which will be described later, and the bevel plane  222   a  forms 45° relative to the W direction. If necessary, the bevel plane  222   a  may serve as a transmission mechanism, which will be described later, together with or instead of the bevel  223   a . In this embodiment, the bevel plane  222   a  does not serve as a transmission mechanism. The bevel plane  223   a  restricts a movement of the operation member  220  in the W 1  direction in cooperation with the bevel  232   a  of a cam projection  232 . 
     The projection  223  projects from a right side of the operation member  220  in the W 2  direction. The projection part  223  has a bevel plane  223   a , and a projection  223   b  provided on the bevel plane  223   a , exhibiting two functions. 
     The first function is a function of a transmission member. The transmission mechanism is a mechanism that converts a direction of the driving force applied to the operation button  221  in the L 2  direction, transmits the converted driving force to the hook  236  of the lock member  230 , and moves the hook  236  in the W 2  direction. In this embodiment, one of the transmission mechanisms includes a projection  223   b  provided on the bevel plane  223   a  of the projection part  223 , and a bevel plane  233   b  of the cam projection  233  of the lock member  230 . The projection part  223  contacts the bevel plane  233   b  via the projection  223   b . This is because the contact between the bevel planes  223   a  and  233   b  would possibly cause an unsmooth relative movement due to frictions. However, the present invention does not prohibit a surface contact between them. In addition, the bevel plane  233   b  may have a projection, and the bevel plane  223  may have no projection. 
     The second function is a stabilization function. A contact between the projection part  223  and the bevel plane  233   b  would prevent a rotation of the operation button  221  in a C 1  direction. 
     A pair of guide grooves  224  extends in the L direction perpendicular to the front surface  135  of the display unit  130  shown in  FIG. 12 . Each base  247   a  of the rod  247  provided onto the base  240  is inserted into a pair of guide grooves  224 . The number of guide grooves and the number of rods are not limited, and an arrangement of each of the guide groove and the rod is not also limited, as long as they correspond to the guide grooves  235 , which will be described later. A guidance operation between a pair of groove guides  224  and the rods  247  prevents unstableness in the W direction when the operation member  220  is moving. 
     The central groove  226  is provided behind the central backside of the operation member  220 , as shown in  FIG. 17 . When viewed from the top, the central groove  226  has an approximately parallelogram shape, and has a pair of bevel planes  226   a  and  226   c , and a projection  226   b  formed on the bevel plane  226   a . The bevel plane  226   a  opposes to a bevel plane  234   a  of the cam projection  234 , and the bevel plane  226   c  opposes to a bevel plane  234   b  of the cam projection  234 . The bevel planes  226   a ,  226   c ,  234   a  and  234   b  incline by an angle of 45° to the W direction. The central groove  226  contacts the bevel plane  234   a  via the projection  226   b  of the bevel plane  226   a . A contact between the projection  226   b  and the bevel plane  234   a  would prevent a rotation of the operation button  221  in the C 2  direction. In this embodiment, during the movement of the operation button  221 , the projection  223   b  moves on the bevel plane  233   b , and the projection  226   b  moves on the bevel plane  234   a . The bevel plane  226   c  and the  234   b  restrict a movement of the operation member  220  in the W 1  direction. 
     Similar to the bevel planes  223   a  and  233   b , the present invention does not prohibit a surface contact between the bevel planes  226   a  and  234   a . Only one of the bevel planes  226   a  and  234   a  may have a projection. The bevel planes  226   c  and  234   b  may serve as a transmission mechanism, or only one of them may have a projection, similar to the bevel planes  222   a  and  232   a . Similar to the guide groove  168 , an inclination angle of each of the bevel planes  223   a ,  226   a ,  233   b , and  234   a  is 45°. 
     This embodiment converts a direction of the driving force applied to the operation button  221  in the L 2  direction into the W 2  direction, and transmits the converted driving force to the hook  236  of the lock member  230 , but the present invention does not limit the driving-force direction and a conversion direction, similar to the first embodiment. 
     The lock part  230  serves to lock the housing in the folded state, and can move in the W direction. The lock part  230  includes a base  231 , cam projections  232 ,  233 , and  234 , and a pair of guide grooves  235 , a hook  236 , a shaft  237  and is made, for example, of polyacetal. 
     The base  231  is a plate member that is movable in the W direction. Part of the shaft  237  is supported on a side surface  231   a  at the right side. As a result, the force by the forcing member  250  is applied to the side surface  231   a , and the hook  236  is forced in the W 1  direction. 
     The cam projection  232  is an approximately right-angled triangle-pole projection provided at the front left corner, and has the bevel plane  232   a . The cam projection  232  is integrated with the base  231 . In this embodiment, the bevel plane  232   a  does not contact the bevel plane  222   a , but the bevel plane  232   a  may contact the bevel plane  222   a  as discussed above. 
     The cam projection  233  is an approximately right-angled triangle-pole projection provided at the back right corner, and has a side surface  233   a , the bevel plane  233   b , and a hollow  233   c . The cam projection  233  is integrated with the base  231 . The side surface  233   a  supports part of the shaft  237  together with the side surface  231   a . As a result, the force by the forcing member  250  is applied to the side surface  233   a  to force the hook  236  in the W 1  direction. The bevel plane  233   b  contacts the projection  223   b  of the bevel plane  223   a  as discussed above, and the projection  223   b  moves on the bevel plane  233   b . The hollow  233   c  is formed to lighten the lock unit  200 . In another embodiment, the side surface  231   a  of the base  231  and the side surface  233   a  of the cam projection  233  are formed as a sidewall similar to the sidewall  172   b . The bevel plane  233   b  may be formed as a plate member separate from the side surface  233   a.    
     The cam projection  234  is a square-pole projection with an approximately parallelogram section provided at the back center, and has a pair of bevel planes  234   a  and  234   b , and a hollow  234   c . The cam projection  234  is integrated with the base  231 . The bevel plane  234   a  contacts the projection  226   b  of the bevel plane  226   a , as discussed above, and the projection  226   b  moves on the bevel plane  234   a . In this embodiment, the bevel plane  234   b  does not contact the bevel plane  226   c , but may contact the bevel plane  226   c , as discussed above. The hollow  234   c  is formed to lighten the lock unit  200 . In another embodiment, the bevel planes  234   a  and  234   b  may be formed as a pair of plate members. 
     A pair of guide grooves  235  extends in the W direction parallel to the front surface  135  of the display unit  130  shown in  FIG. 12 . The bases  247   a  of the rods  247  provided onto the base  240  are inserted into a pair of guide grooves  235 . The number of guide grooves and the number of rods are not limited, and an arrangement of each of the guide groove and the rod is not also limited. However, the guide groove and the rod must correspond to the above guide grooves  224 . A guidance operation between a pair of guide grooves  224  and the rod  247  in the W direction would prevent unstableness in the L direction when the operation member  220  is moving. 
     The hook  236  is a hook member that is engaged with the back surface of the upper cover  111  and serves to lock the housing in the folded state. The hook  236  projects from the back surface of the base  231 , and is movable with the base  231  in the W direction. The hook  236  is inserted into the perforation hole  245 , and its movement in the W direction is restricted. The end of the perforation hole  245  in the W 1  direction is a lock position at which the hook  236  is engaged with the back surface of the upper cover  111 , and the end of the perforation hole  245  in the W 2  direction is an unlock position at which the hook  236  is disengaged from the back surface of the upper cover  111 . 
     The shaft  237  supports the compression spring  250  that serves as a forcing member, and serves to guide a movement of the lock member  230  in the W direction. The shaft  237  serves to hold the forcing member and to guide a movement of the lock member  230 , effectively utilizing the housing space. The shaft  237  is a rod, one end of which is fixed onto the side surfaces  231   a  and  233   a , and extends in the W 2  direction. The other end of the shaft  237  is engaged with an engagement groove  242  of a holder  241   b  of the base  240  shown in  FIG. 13 . The forcing member is not limited to the compression spring, and may be another member, such as cylindrical rubber, as long as it satisfies the function in the present invention. 
     The base  240  serves to accommodate each part of the lock unit  140  in cooperation with the top plate  210 , and to guide and restrict a movement of the lock member  230 . The base  240  includes a pair of holders  241   a  and  241   b , two pairs of projections  243  and  247 , a perforation hole  245 , and a support member  246 . The base  240  is made, for example, a blend of polycarbonate and ABS resin, and integrated with to the back surface of the front cover  131  of the display unit  130 . 
     A pair of holders  241   a  and  241   b  each has an L shape, defines an outline of the lock unit  200 , and holds the top plate  210 . The holder  241   a  contacts the side surface of the cam projection  232  of the base  231 , and restricts its movement. The holder  241   b  has the engagement groove  242  that supports the shaft  237 . The inside of the sidewall having the engagement groove  242  of the holder  241   b  contacts an end  250   b  of the forcing member  250 . A pair of rods  243  is formed at one corner of each of the holders  241   a  and  241   b . A pair of rods  243  is inserted into a pair of attachment holes  212  of the top plate  210 . The hook  236  is inserted into the perforation hole  245 . The support member  246  supports the operation button  221 . Each rod  247  has the base  247   a  and tip  247   b . The base  247   a  and the tip  247   b  have a cylindrical shape, and the tip  247   b  is smaller in diameter than the base  247   a . The bases  247   a  perforate through two pairs of guide grooves  224  and  235 . Each tip  247   b  is attached to the attachment hole  217 , and covered with a cap (not shown) that is engaged with the support member  216 . 
     The forcing member  250  serves as a forcing member that forces the hook  236  towards the lock position, and as a forcing member that forces the operating member  220  towards the projection position. One forcing member  250  serves two forcing functions, and contributes to the effective utilization of the housing space. The forcing member  250  includes a compression spring, and is penetrated by the shaft  237 . One end  250   a  of the forcing member  250  contacts the side surfaces  231   a  and  233   a , and the other end  250   b  contacts the inside of the sidewall having the engagement groove  242  of the holder  241 . As a result of that the forcing member  250  forces the lock member  230  in the W 1  direction, the hook  236  is forced to the lock position. A direction of the force which the forcing member  250  applies to the lock member  230  is converted by the projections  223   b  and  226   b  and the bevel planes  233   b  and  234   a , and transmitted to the operation member  220 . As a consequence, the operation member  220  projects in the L 1  direction. 
     Referring now to  FIGS. 18-20 , a description will be given of the opening and closing actions of the housing. Here,  FIG. 18  is a top view of the laptop PC  100 A in the lock state.  FIG. 19A  is an NN sectional view of  FIG. 18  in the lock state, and  FIG. 19B  is an enlarged sectional view of A3 part in  FIG. 19A  in the lock state.  FIG. 20A  is the NN sectional view of  FIG. 18  in the unlock state.  FIG. 20B  is an enlarged sectional view of A4 part of  FIG. 20A  in the unlock state.  FIG. 20C  is an enlarged plane view of the inside of the lock unit in the unlock state. 
     In the lock state shown in  FIGS. 18 ,  19 A to  19 C, the base  247   a  of the rod  247  is located at the (back) end of the guide groove  224  on the L 2  side and the (right) end of the guide groove  235  on the W 2  side in  FIG. 13  due to the force by the forcing member  250 . As a result, the operation button  221  projects from the housing in the L 1  direction, and the hook  236  is located at the end of the perforation hole  245  on the W 1  direction side, and contacts the back surface of the upper cover  111  as shown in  FIG. 19B . In the lock state, due to the engagement between the hook  236  and the upper cover  111 , the display unit  130  cannot be lifted. 
     Next, the user presses the operation button  221  shown in  FIG. 13  in the L 2  direction. When the operation member  220  moves in the L 2  direction due to the engagement between the base  247   a  and the guide groove  224 , the base  231  moves in the W 2  direction due to the action of the transmission mechanism. As a result, the lock member  230  moves in the W 2  direction against the force of the forcing member  250  until the hook  236  moves to the end in the perforation hole  245  on the W 2  direction side. 
     In the unlock state shown in  FIGS. 20A to 20C , each base  247   a  is located at the (front) end of the guide groove  224  in the L 1  side and at the (left) end of the guide groove  235  at the W 1  side in  FIG. 13 . The operation button  221  retreats to the end on the L 2  direction side, and the hook  236  is located at the end in the perforation hole  245  on the W 2  direction side, and spaced from the back surface of the upper cover  111  as shown in  FIG. 20B . In the unlock state, the hook  236  is not engaged with the upper cover  111 , and the display unit  130  can be lifted upwardly (in the R 2  direction). 
     The operation is similar to that of the first embodiment after the display unit  130  is unfolded to some extent or a desired angle. Also, it is similar to the lock unit  140  that the lock unit  200  improves the operability in comparison with the conventional lock unit  20 . The folding operation after the information is input is also similar to the first embodiment. 
     According to the laptop PC  100 A, the lock unit can be configured in a smaller space. In addition, its operability improves because the display unit  130  is pressed upwardly (in the R 2  direction) while the operation button  221  is pressed in the L 2  direction. 
     Further, the present invention is not limited to these preferred embodiments, and various variations and modifications may be made without departing from the scope of the present invention. For example, a similar effect can be obtained even when the hook  174  is configured to face the right and the shaft  175  and the forcing member  190  may be provided at the sidewall  172   a  side, and the guide groove  168  may extend in the right oblique direction in  FIG. 3 . In addition, while this embodiment configures the hooks  174  and  236  displaceable, the hook  174  or  236  may be fixed and an engagement member may be provided in the engagement hole  116  so as to be engageable with the hook  174  or  236 , and the lock unit may be provided in the body  110  to make the engagement member displaceable. 
     Thus, the present invention can provide a lock unit and an electronic apparatus having the same, which can effectively utilize the housing space and the operability.