Abstract:
A cam device has an improved stableness in operability including a first member and a second member incorporated with each other. The first member has an engaging surface defining engaging portions moveable relative to engaging portions on an engaging surface of the second member. Each engaging portion has a top edge having two ends, a first slope extending from one end of the top edge, and a second slope extending from the other end of the top edge. Each first slope has one other first slope circumferentially spaced at an angle of 180° and each second slope has one other second slope circumferentially spaced at an angle of 180°. Additionally, each engaging portion has a central angle measured from a point within the cam device and an imaginary line dividing the central angle in half adapted to cooperate with another line to form an angle of 180°

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a cam device, in particular to a cam device that is incorporated with a hinge and such a cam device has an improved stableness in operability. 
         [0003]    2. Description of the Related Art 
         [0004]    Referring to China Patent No. 200620137499.1, a cam device includes a first member having protrusions that are formed of points abutting against a second member and that are moveably relative to the second member. While it is advantageous that the first and second members have relative small engagement areas for noise reduction during operation, these engagements however suffer rocking motions between relative movement of the first and second members rendered by any elastic behavior of resilient elements incorporated with the cam device. Additionally, the cam device has not yet provided the most effortless way for starting relative movement of the first and the second members. 
         [0005]    Referring to China Patent No. 200620115146.1, a cam device that is more durable for use is disclosed. However, the cam device still suffers the abovementioned problems. 
         [0006]    The present invention is, therefore, intended to obviate or at least alleviate the problems encountered in the prior art. 
       SUMMARY OF THE INVENTION 
       [0007]    In one aspect of the present invention, a cam device includes a first member and a second member incorporated with each other. The first member has an engaging surface defining engaging portions moveable relative to engaging portions on an engaging surface of the second member. Each engaging portion has a top edge having two ends, a first slope extending from one end of the top edge, and a second slope extending from the other end of the top edge. Each first slope has one other first slope circumferentially spaced at an angle of 180° and each second slope has one other second slope circumferentially spaced at an angle of 180°. Additionally, each engaging portion has a central angle measured from a point within the cam device and an imaginary line dividing the central angle in half adapted to cooperate with the other similar line of the other engaging portion to form an angle of 180° 
         [0008]    In another embodiment of the present invention, each engaging portion has an imaginary line dividing the central angle in half and adapted to cooperate with the other similar line of the other engaging portion to form an angle of 90°. 
         [0009]    There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are additional features of the invention that will be described hereinafter and which will form the subject matter of the claims appended hereto. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    For the present disclosure to be easily understood and readily practiced, the present disclosure will now be described in conjunction with the following figures, wherein; 
           [0011]      FIG. 1  is an exploded perspective view of a cam device in accordance with a first embodiment of the present invention. 
           [0012]      FIG. 2  is a side view of the cam device of the present invention. 
           [0013]      FIG. 3  is a cross-sectional view taken along line  3 - 3  of  FIG. 2 . 
           [0014]      FIG. 4  is an operational position of the cam device of  FIG. 1 . 
           [0015]      FIG. 5  is a cross-sectional view taken along line  5 - 5  of  FIG. 4 . 
           [0016]      FIG. 6  is an exploded perspective view of a cam device in accordance with a second embodiment of the present invention. 
           [0017]      FIG. 7  is a sectional view showing an operational position of the cam device of  FIG. 6 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0018]    Referring to  FIGS. 1 through 5 , a cam device  10  in accordance with a first embodiment of the present invention comprises a first member  20  and a second member  30  incorporated with each other. The first and the second members  20  and  30  are coaxially positionable on a pivoting element, preferably a pin-like structure. The pin is inserted though a hole  201  defined in the first member  20  and a hole  301  defined in the second member  30 . Additionally, the first member  20  may have a hooking portion  202  adapted to incorporate with a supporting bracket (not shown) of a hinge assembly. 
         [0019]    The first member  20  has an engaging surface and the second member  30  has an engaging surface positioned against the engaging surface of the first member  20  and moveable relative to the engaging surface of the first member  20 . As best shown in  FIG. 3 , the engaging surface of the first member  20  defines an inner section  205  and an outer section  206 . The inner section  205  has an inner perimeter that coincides with the perimeter of the hole  201  and an outer perimeter  203 . The outer section  206  has an inner perimeter that coincides with the outer perimeter  203  of the inner section  205  and an outer perimeter that coincides with a perimeter  204  of the engaging surface of the first member  20 . 
         [0020]    The inner section  205  has a first and a second engaging portions  21  and  22 , preferably a protruded configuration, thereon and spaced by a third and a fourth engaging portions  25  and  26  forming portions of surface defining the inner section  205 . The first, second, third and fourth engaging portions  21 ,  22 ,  25  and  26  have shapes symmetrical with respect to line V. Additionally, the first and the second engaging portions  21  and  22  have their respective central angles with respect to point O halved by line V and therefore a line dividing the central angle of the first engaging portion  21  in half and a line dividing the central angle of the second engaging portion  22  in half cooperate to form an angle of 180° and these lines coincide with line V. Additionally, the third and fourth engaging portions  25  and  26  are disposed symmetrically with respect to line V and have their respective central angles with respect to point O being equal. 
         [0021]    In addition, the first engaging portion  21  defines a top edge  213  which is preferably a planar surface, a slope  211  bridging the third engaging portion  25  and the top edge  213 , a slope  212  bridging the fourth engaging portion  26  with the top edge  213 , and two chamfered edges  214 , with one interconnecting the slope  211  and the top edge  213  and another interconnecting the slope  212  and the top edge  213 . The second engaging portion  22  defines a top edge  223  which is preferably a planar surface, a slope  221  bridging the fourth engaging portion  26  and the top edge  223 , a slope  222  bridging the third engaging portion  25  with the top edge  223 , and two chamfered edges  224 , with one interconnecting the slope  221  and the top edge  223  and another interconnecting the slope  222  and the top edge  223 . 
         [0022]    The outer section  206  has a first and a second engaging portions  23  and  24 , preferably a protruded configuration, thereon and spaced by a third and a fourth engaging portions  27  and  28  forming portions of surface defining the outer section  206 . The first, second, third and fourth engaging portions  23 ,  24 ,  27  and  28  have shapes symmetrical with respect to line V. Additionally, the first and second engaging portions  23  and  24  have their respective central angles with respect to point O halved by line V and therefore a line dividing the central angle of the first engaging portion  23  in half and a line dividing the central angle of the second engaging portion  24  in half cooperate to form an angle of 180° and these lines coincide with line V. Additionally, the third and fourth engaging portions  27  and  28  are disposed symmetrically with respect to line V and have their respective central angles with respect to point O being equal. 
         [0023]    In addition, the first engaging portion  23  defines a top edge  233  which is preferably a planar surface, a slope  231  bridging the third engaging portion  27  and the top edge  233 , a slope  232  bridging the fourth engaging section  28  and the top edge  233 , and two chamfered edges  234 , with one interconnecting the slope  231  and the top edge  233  and another interconnecting the second slope  232  and the top edge  233 . The second engaging portion  24  defines a top edge  243  which is preferably a planar surface, a slope  241  bridging the fourth engaging portion  28  and the top edge  243 , a slope  242  bridging the third engaging section  27  and the top edge  243 , and two chamfered edges  244 , with one interconnecting the slope  241  and the top edge  243  and another interconnecting the second slope  242  and the top edge  243 . 
         [0024]    Moreover, the slope  211  of the first engaging portion  21  on the inner section  205  is circumferentially spaced from the slope  231  of the first engaging portion  23  on the outer section  206  at an angle of 180°; the slope  212  of the first engaging portion  21  on the inner section  205  is circumferentially spaced from the slope  232  of the first engaging portion  21  on the outer section  206  at an angle of 180°; the slope  221  of the second engaging portion  22  on the inner section  205  is circumferentially spaced from the slope  241  of the second engaging portion  24  on the outer section  206  at an angle of 180°; and the slope  222  of the second engaging portion  22  on the inner section  205  is circumferentially spaced from the slope  242  of the second engaging portion  24  on the outer section  206  at an angle of 180°. 
         [0025]      FIG. 3  also shows that the engaging surface of the second member  30  defines an inner section  305  and an outer section  306 . The inner section  305  has an inner perimeter that coincides with the perimeter of the hole  301  and an outer perimeter  303 . The outer section  306  has an inner perimeter that coincides with the outer perimeter  303  of the inner section  305  and an outer perimeter that coincides with a perimeter  304  of the engaging surface of the second member  30 . 
         [0026]    The inner section  305  has a first and a second engaging portions  31  and  32 , preferably a protruded configuration, thereon and spaced by a third and a fourth engaging portions  35  and  36  forming portions of surface delimiting the inner section  305 . The first, second, third and fourth engaging portions  31 ,  32 ,  35  and  36  have shapes symmetrical with respect to line V. Additionally, the first and second engaging portions  31  and  32  are disposed symmetrically with respect to line V and have their respective central angles with respect to point O being equal. Additionally, the third and fourth engaging portions  35  and  36  have their respective central angles with respect to point O halved by line V and therefore a line dividing the central angle of the third engaging portion  35  in half and a line dividing the central angle of the fourth engaging portion  36  in half cooperate to form an angle of 180° and these lines coincide with line V. 
         [0027]    In addition, the first engaging portion  31  defines a top edge  313  which is preferably a planar surface, a slope  311  bridging the third engaging portion  35  and the top edge  313 , a slope  312  bridging the fourth engaging portion  36  with the top edge  313 , and two chamfered edges  314 , with one interconnecting the slope  311  and the top edge  313  and another interconnecting the slope  312  and the top edge  313 . The second engaging portion  32  defines a top edge  323  which is preferably a planar surface, a slope  321  bridging the fourth engaging portion  36  and the top edge  323 , a slope  322  bridging the third engaging portion  35  with the top edge  323 , and two chamfered edges  324 , with one interconnecting the slope  321  and the top edge  323  and another interconnecting the slope  322  and the top edge  323 . 
         [0028]    The outer section  306  has a first and a second engaging portions  33  and  34 , preferably a protruded configuration, thereon and spaced by a third and a fourth engaging portions  37  and  38  forming portions of surface defining the outer section  206 . The first, second, third and fourth engaging portions  33 ,  34 ,  37  and  38  have shapes symmetrical with respect to line V. Additionally, the first and second engaging portions  33  and  34  are disposed symmetrically with respect to line V and have their respective central angles with respect to point O being equal. Additionally, the third and fourth engaging portions  37  and  38  have their respective central angles with respect to point O halved by line V and therefore a line dividing the central angle of the third engaging portion  37  in half and a line dividing the central angle of the fourth engaging portion  38  in half cooperate to form an angle of 180° and these lines coincide with line V. 
         [0029]    Moreover, a line dividing the central angle of the first engaging portion  31  on the inner section  305  in half and a line dividing the central angle of the first engaging portion  33  on the outer section  306  in half cooperate to form an angle of 180°; a line dividing the central angle of the second engaging portion  32  on the inner section  305  in half and a line dividing the central angle of the second engaging portion  34  on the outer section  306  in half cooperate to form an angle of 180°. 
         [0030]    Moreover, the slope  311  of the first engaging portion  31  on the inner section  305  is circumferentially spaced from the slope  331  of the first engaging portion  33  on the outer section  306  at an angle of 180°; the slope  312  of the first engaging portion  31  on the inner section  305  is circumferentially spaced from the slope  332  of the first engaging portion  33  on the outer section  206  at an angle of 180°; the slope  321  of the second engaging portion  32  on the inner section  305  is circumferentially spaced from the slope  341  of the second engaging portion  34  on the outer section  306  at an angle of 180°; and the slope  322  of the second engaging portion  32  on the inner section  305  is circumferentially spaced from the slope  342  of the second engaging portion  34  on the outer section  306  at an angle of 180°. 
         [0031]    In addition, the first engaging portion  33  defines a top edge  333  which is preferably a planar surface, a slope  331  bridging the third engaging portion  37  and the top edge  333 , a slope  332  bridging the fourth engaging section  38  and the top edge  333 , and two chamfered edges  334 , with one interconnecting the slope  331  and the top edge  333  and another interconnecting the second slope  332  and the top edge  333 . The second engaging portion  34  defines a top edge  343  which is preferably a planar surface, a slope  341  bridging the fourth engaging portion  38  and the top edge  343 , a slope  342  bridging the third engaging section  37  and the top edge  343 , and two chamfered edges  344 , with one interconnecting the slope  341  and the top edge  343  and another interconnecting the slope  342  and the top edge  343 . 
         [0032]    The central angles of the first engaging portion  21  of the first member  20  and third engaging portions  35  of the second member  30  are substantially equal, the central angles of the second engaging portion  22  of the first member  20  and the fourth engaging portions  36  of the second member  30  are substantially equal, the central angles of the first engaging portion  23  of the first member  20  and the third engaging portions  37  of the second member  30  are substantially equal, and the central angles of the second engaging portion  24  of the first member  20  and the fourth engaging portions  38  of the second member  30  are substantially equal. Also, the central angles of the first engaging portion  31  of the second member  30  and third engaging portions  25  of the first member  20  are substantially equal, the central angles of the second engaging portion  32  of the second member  30  and the fourth engaging portions  26  of the first member  20  are substantially equal, the central angles of the first engaging portion  33  of the second member  30  and the third engaging portions  27  of the first member  20  are substantially equal, and the central angles of the second engaging portion  34  of the second member  30  and the fourth engaging portions  28  of the first member  30  are substantially equal. Thus, the first and second members  20  and  30  can be positioned with respect to each other such that the engaging portions  21 ,  22 ,  23  and  24  are complemently received in the engaging portions  35 ,  36 ,  37 , and  38  and the engaging portions  31 ,  32 ,  33  and  34  are complemently received in the engaging portions  25 ,  26 ,  27 , and  28 , as shown in  FIG. 3 . 
         [0033]    When the second member  30  is rotated clockwise with respect to first member  20 , as best shown in  FIG. 5 , the top edge  313  defined by the first engaging portion  31  at the inner section  305  of the second member  30  is moved to gradually engage with the top edge  213  defined by the first engaging portion  21  at the inner section  205  of the second member  20 , and this area of contact is defined as A 1 . The top edge  323  defined by the second engaging portion  32  at the inner section  305  of the second member  30  is moved to gradually engage with the top edge  223  defined by the second engaging portion  22  at the inner section  205  of the second member  20 , and the area of contact is defined as A 2 . The top edge  333  defined by the first engaging portion  33  at the outer section  306  of the second member  30  is moved to gradually engage with the top edge  233  defined by the first engaging portion  23  at the outer section  206  of the first member  20 , and this area of contact is defined as A 3 . The top edge  343  defined by the second engaging portion  34  at the outer section  306  of the second member  30  is moved to gradually engage with the top edge  243  defined by the second engaging portion  24  at the outer section  206  of the first member  20 , and this area of contact is defined as A 4 . 
         [0034]    Preferably, areas A 1  and A 2  are kept symmetrical with respect to line L and areas A 3  and A 4  are kept symmetrical with respect to line L, respectively. Line L is a line passing through point O. Thus, the second member  30  can engage with the first member  20  in a very stable manner and it is not a problem that any elastic behavior would rock the engagement throughout the process, particularly at initial stage thereof, which is normally a problem of the conventional cam devices. 
         [0035]    In addition, the top edge  313  can be easily pushed to engage with the top edge  213  (area of contact is defined as A 1 ) without any rocking movement by cooperation of the slope  211  and the chamfered edge  214  between the slope  211  and the top edge  213  with the slope  311  and the chamfered edge  314  between the slope  311  and the top edge  313 . Likewise, the top edge  313  can be easily pushed to disengage with top edge  213  without any rocking movement by cooperation of the slope  212  and the chamfered edge  214  between the slope  212  and the top edge  213  with the slope  312  and the chamfered edge  314  between the slope  312  and the top edge  313 . Similarly, other engagement of top edges involved, such as A 2 , A 3 , and A 4 , would also be easily performed without any rocking movement. 
         [0036]      FIGS. 6 and 7  show an alternate cam device  10 ′ in accordance with a second embodiment of the present invention. Similar to the prior embodiment, a line dividing a central angle (measured with respect to O) of the first engaging portion  21 ′ on the inner section  205 ′ of the first member  20 ′ in half and a line dividing a central angle (measured with respect to O) of second engaging portion  22 ′ on the inner section  205 ′ of the first member  20 ′ in half cooperate to form an angle of 180°; and a line dividing a central angle (measured with respect to O) of the first engaging portion  23 ′ on the outer section  206 ′ of the first member  20 ′ in half and a line dividing a central angle (measured with respect to O) of the second engaging portion  24 ′ on the outer section  206 ′ of the first member  20 ′ in half cooperate to form an angle of 180°. But the lines associated with the first and second engaging portions  21 ′ and  22 ′ and the lines associated with the first and second engaging portions  23 ′ and  24 ′ cooperate to form an angle of 90°. 
         [0037]    Additionally, the slope  211 ′ of the first engaging portion  21 ′ on the inner section  205 ′ is spaced from the slope  221 ′ of the second engaging portion  22 ′ on the inner section  205 ′ at an angle of 180°; the slope  212 ′ of the first engaging portion  21 ′ on the inner section  205 ′ is spaced from the slope  222 ′ of the second engaging portion  22  on the inner section  205 ′ at an angle of 180°; the slope  231 ′ of the first engaging portion  22 ′ on the outer section  306 ′ is spaced from the slope  241 ′ of the second engaging portion  24 ′ on the outer section  206 ′ at an angle of 180°; and the slope  232 ′ of the second engaging portion  23 ′ on the outer section  206 ′ is spaced from the slope  242 ′ of the second engaging portion  24 ′ on the outer section  206 ′ at an angle of 180°. 
         [0038]    Also, a line dividing a central angle (measured with respect to O) of the first engaging portion  31 ′ on the inner section  305 ′ of the second member  30 ′ in half and a line dividing a central angle (measured with respect to O) of the second engaging portion  32 ′ on the inner section  305 ′ of the second member  30 ′ in half cooperate to form an angle of 180°; a line dividing the central angle of the first engaging portion  33 ′ on the outer section  306 ′ of the second member  30 ′ in half and a line dividing a central angle of the second engaging portion  34 ′ on the outer section  306 ′ of the second member  30 ′ in half cooperate to form an angle of 180°. The lines associated with the first and second engaging portions  31 ′ and  32 ′ and the lines associated with the first and second engaging portions  33 ′ and  34 ′ cooperate to form an angle of 90°. 
         [0039]    While the specific embodiments have been illustrated and described, numerous modifications come to mind without significantly departing from the spirit of invention and the scope of invention is only limited by the scope of accompanying claims.