Abstract:
A joystick includes an operating stick having shaft portions protruded from a lower end thereof, an upper arm which supports the operating stick so as to be pivotable in a first direction, a lower arm which supports the operating stick so as to be pivotable in a second direction which is perpendicular to the first direction, and bearing portions which are formed at a lower face of the central portion of the lower arm for bearing the shaft portions. The bearing portions are concaved, and the shaft portions are fitted into the bearing portions from a lower side respectively.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates to a joystick and, in particular, relates to a compact joystick in which an arm member thereof is wall thickness thereby to strengthen and improve the durability thereof.  
           [0002]    Such a kind of related joystick will be explained with reference to FIGS. 7 and 8. In the figures, a joystick  1  is configured in a manner that arms  3  and  4  being orthogonal to each other in the vertical direction are disposed so as to rotate freely within a casing  2 . Each of the arms  3  and  4  is pivotally supported at the both end portions thereof by the casing  2 . The one end portions of the arms  3  and  4  are connected to variable resistors  5 ,  6  serving as signal output unit, respectively.  
           [0003]    Long holes  7 ,  8  extending in the longitudinal directions of the arms  3 ,  4  are opened at the center portions of the arms  3 ,  4 , respectively. An operation stick  9  serving as an operation stick is provided so as to pass through the long holes  7 ,  8 . The lower end portion of the operation stick  9  is formed as a convex-shaped spherical portion  9   a . A concave-shaped spherical portion  10   a  is formed at the center portion of the base  10  of the joystick  1 . The convex-shaped spherical portion  9   a  is disposed at the concave-shaped spherical portion  10   a  so as to rotate freely. A knob (not shown) is fitted into the upper end portion of the operation stick  9 .  
           [0004]    When the operation stick  9  is operated, the operation stick  9  rotates around the concave-shaped spherical portion  10   a  serving as a rotation fulcrum, then the operation stick  9  rotates the arms  3  and  4  thereby to rotate the variable resistors  5  and  6  coupled to the arms  3  and  4 , so that the variable resistors  5  and  6  generate outputs according to the operation of the operation stick  9 .  
           [0005]    Further, as shown in FIG. 8, the operation stick  9  of the joystick  1  has shaft portions  11  protrusively provided at the left and right portions of the lower portion thereof, respectively. The shaft portions  11  are fitted into shaft holes  13 , which are formed at the center portions of inside wall portions  12 ,  12  forming the long hole  8  perforated at the lower arm  4 , in a pin-coupling method so as to rotate freely, respectively. Then, the operation stick  9  and the arms  3 ,  4  are fixed in the vertical direction. In order to hold the arms  3 ,  4  at the neutral portions, a coil spring  15  is disposed between the base  10  and a ring-shaped supporting member  14  which is largely perforated at the center portion thereof abutting against the lower face of the lower arm  4  and has a reverse-U shape in its section.  
           [0006]    However, according to the related compact joystick, the shaft portions protrusively provided at the lower portion of the operation stick are forcedly inserted and fitted into the shaft holes perforated at the lower side arm so as to rotate freely.  
           [0007]    Thus, when a user operates such a compact joystick heavily, an intense force acts on the arm which tries to restore to the neutral position due to the coil spring. In particular, a more load is applied to the arm near the shaft portions of the operation stick due to a load applied from the upper side and action of a lever. Thus, the arm deforms due to the load and so the durability of the joystick is remarkably degraded. Such a phenomenon appears remarkably in the case of a compact joystick formed by processing plastics.  
         SUMMARY OF THE INVENTION  
         [0008]    It is therefore an object of the present invention to provide a joystick, in which an arm is not deformed even if a user heavily operates a compact joystick and a rigid and durable joystick can be expected.  
           [0009]    In order to achieve the above object, according to the present invention, there is provided a joystick comprising:  
           [0010]    an operating stick, having shaft portions protruded from a lower end thereof;  
           [0011]    an upper arm, which supports the operating stick so as to be pivotable in a first direction;  
           [0012]    a lower arm, which supports the operating stick so as to be pivotable in a second direction which is perpendicular to the first direction; and  
           [0013]    bearing portions, which are formed at a lower face of the central portion of the lower arm for bearing the shaft portions, and the bearing portions being concaved;  
           [0014]    wherein the shaft portions are fitted into the bearing portions from a lower side respectively.  
           [0015]    In the above configuration, the lower arm is provided with bearing portions being opened at their lower faces which are formed by removing the lower faces of the center portions of both the side wall portions forming a long hole passed through the operating stick in almost semicircular shapes, respectively, and the shaft portions of the operation stick are abutted against and fitted into the bearing portions from a lower side, respectively. Thus, unlike the related example, the operation stick is not required to be fitted into the shaft hole perforated at the arm by utilizing the elasticity of the arm. Thus, it is possible to make the arm well round or fat.  
           [0016]    Preferably, the shaft portions have different diameters, and the bearing portions into which the shaft portions is fitted have corresponding diameters respectively.  
           [0017]    Preferably, the bearing portions are semicircular recessed portions.  
           [0018]    In the above configurations, the arm is removed in its thickness by a size corresponding to the moving amount of the operation stick, that is, only for portions corresponding to the long hole provided at a longitudinal direction of the arm and the bearing portions being opened in their lower face for fitting the shaft portions therein. Thus, the arm becomes more rigid and the durability thereof is remarkably improved. Accordingly, the invention can attain quite remarkable effects. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]    The above objects and advantages of the present invention will become more apparent by describing in detail preferred exemplary embodiments thereof with reference to the accompanying drawings, wherein:  
         [0020]    FIG . 1  is a plan view of a joystick according to an embodiment of the invention;  
         [0021]    [0021]FIG. 2 is a sectional view along a line B-B in FIG. 1;  
         [0022]    [0022]FIG. 3 is a sectional view along a line C-C in FIG. 1;  
         [0023]    [0023]FIG. 4 is a perspective view of an operation stick;  
         [0024]    [0024]FIG. 5A is a perspective view of an upper arm seen from the lower side;  
         [0025]    [0025]FIG. 5B is a perspective view of the upper arm seen from the upper side;  
         [0026]    [0026]FIG. 6A is a perspective view of an lower arm seen from the lower side;  
         [0027]    [0027]FIG. 6B is a perspective view of the lower arm seen from the upper side;  
         [0028]    [0028]FIG. 7 is a plan view of an example of related joysticks; and  
         [0029]    [0029]FIG. 8 is a sectional view along a line A-A in FIG. 7. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0030]    The embodiment of the invention will be explained in detail with reference to FIGS.  1  to  6 . In this respect, portions same as those of the related technique are explained for the convenience of explanation.  
         [0031]    In FIG. 1, a reference numeral  20  depicts a joystick. The joystick  20  is configured in a manner that an upper arm  22  serving as an upper arm and a lower arm  23  being orthogonal to each other in the vertical direction are disposed so as to rotate freely within a casing  21 . Each of the upper arm  22  and the lower arm  23  is pivotally supported at the both end portions thereof by the casing  21 . The one end portions of the upper arm  22  and the lower arm  23  are connected to variable resistors  24 ,  25 , respectively.  
         [0032]    Long holes  26 ,  27  extending in the axial directions of the upper arm  22  and the lower arm  23  are opened at the center portions thereof, respectively. An operation stick  28  is provided so as to pass through the long holes  26 ,  27 . The lower end portion of the operation stick  28  is formed as a convex-shaped spherical portion  28   a . A concave-shaped spherical portion  21   a  is formed at the center portion of the upper portion of the base  21   b  of the joystick  20 . The convex-shaped spherical portion  28   a  is disposed on the concave-shaped spherical portion  21   a  so as to swing freely. A knob (not shown) is fitted into the upper end portion of the operation stick  28 .  
         [0033]    In the joystick  20  thus configured, When the operation stick  28  is operated, the operation stick  28  rotates around the concave-shaped spherical portion  21   a  serving as a rotation fulcrum, then the operation stick rotates the upper arm  22  and the lower arm  23  thereby to rotate the variable resistors  24  and  25  coupled to the upper arm  22  and the lower arm  23 , respectively, so that the variable resistors  24  and  25  generate outputs according to the operation of the operation stick  28 .  
         [0034]    In order to hold the upper arm  22  and the lower arm  23  respectively at the neutral positions, like the related example, a coil spring  30  is disposed between the base  21   b  and a ring-shaped supporting member  29  which is abutted against the lower face of the lower arm  23 . That is, since the coil spring  30  elastically pushes the lower arm  23  upward, the upper arm  22  and the lower arm  23  are held at the neutral positions, respectively.  
         [0035]    Further, the operation stick  28  is provided with shaft portions  31  protrusively provided at the left and right portions of the lower portion of the operation stick  28  as shown in FIGS. 2 and 4.  
         [0036]    As shown in FIGS. 2 and 6, the lower arm  23  has the side wall portions  23   a  formed by the long hole  27 . Bearing portions  32  are formed at the lower faces of the center portions of the left and right side wall portions  23   a  in almost recessed semicircular shapes, respectively. Thus, the bearing portions  32  are provided in a manner that the lower faces thereof are opened at the side wall portions  23   a  of the lower arm  23 , respectively. Further, the bearing portions  32  are formed to have sizes corresponding to the sizes of the shaft portions  31  which are provided at the operation stick  28  so that the shaft portions are fitted in loosely in the bearing portions. Furthermore, the left and right shaft portions  31  are formed to have different sizes and the bearing portions  32  corresponding thereto also are formed to have different sizes. In this case, in a case where the left and right shaft portions  31  are fitted in from the lower faces of the bearing portions  32 , if the shaft portions are mistakenly fitted in loosely in erroneous bearing portions in a manner that left and right directions are erroneous, the shaft portions  31  of the operation stick  28  can not be fitted into the bearing portions  32 , respectively. Thus, there is no possibility that the operation stick  28  is attached in an erroneous direction.  
         [0037]    Further, since the shaft portions  31  are loosely fitted in from the lower faces of the corresponding bearing portions  32 , respectively, such a mutual fitting operation can be performed easily. The shaft portions  31  are prevented from moving upward due to the presence of the bearing portions  32 . Thus, the bearing portions also serve for preventing the operation stick  28  from dropping out and the shaft portions  31  fit in the lower arm  23  and rotate. Further, the shaft portions  31  coincide with the shafts of the upper arm  22  and the lower arm  23  serving as the upper and lower arms, respectively. The operation stick  28  is prevented from being pushed in by the concave-shaped spherical portion  21   a  provided at the base  21   b.    
         [0038]    In this manner, the joystick  20  is provided with a restriction portion for restricting the assembling direction to a predetermined direction in order to prevent the erroneous assembling. To this end, the respective parts are subjected to various improvement for their configurations and then assembled within the casing  21 , and so the joystick is configured to attain its function smoothly.  
         [0039]    As described above, unlike the related example, the operation stick  28  of the joystick  20  according to the invention is not required to be fitted into the shaft hole perforated at the lower arm  23  by utilizing the elasticity of the lower arm  23 . Thus, it is possible to make the lower arm  23  wall thickness. Further, the lower arm  23  is removed in its thickness by a size corresponding to the moving amount of the operation stick  28 , that is, only for portions corresponding to the long hole  27  and the bearing portions  32  for fitting the shaft portions  31  therein. Thus, particularly, the lower arm  23  becomes more rigid and the durability thereof is improved. Accordingly, such a problem that the arms are deformed or broken can be prevented from occurring even if a user heavily operates the joystick  20 . It is considered to provide sphere portions at the lower portion of the operation stick  28  in place of the shaft portions  31 . However, in this case, if bearing portions are provided at the arm in correspondence with the sphere portions, the lower arm is largely removed in its thickness at portions corresponding to the bearing portions. As a result, it becomes almost impossible to firmly hold the arms and expect the durability.