You are an expert at summarizing long articles. Proceed to summarize the following text:

You are an expert at summarizing long articles. Proceed to summarize the following text: 
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This Application claims the right of priority based on Taiwan Patent Application No. 093113829 entitled “ADJUSTABLE HINGE,” filed on May 17, 2004. 
     FIELD OF THE INVENTION 
     This invention relates to an adjustable hinge for use in a foldable apparatus, more particularly, an adjustable hinge including a rotatable portion and a fixed portion, wherein adjusting the relative position between the rotatable portion and the fixed portion can adjust a maximum opening angle to satisfy different user demands. 
     BACKGROUND OF THE INVENTION 
     A hinge is often used to connect a cover with the body of a foldable apparatus. There are many foldable mobile phones using hinges to connect their bodies and covers. A foldable mobile phone usually has a smaller volume than others not foldable. 
     In the prior art, the maximum opening angle, defined by the cover and the body, is not adjustable. According to different demands of various users, for example, different users having different facial sizes, an adjustable maximum opening angle is required to accommodate the various users. 
     SUMMARY OF THE INVENTION 
     The present invention provides an adjustable hinge for use in a foldable apparatus. The foldable apparatus herein can be a foldable mobile phone. Through adjusting the relative position between the rotatable portion and the fixed portion of the foldable apparatus, an adjustable maximum opening angle can be achieved to satisfy different user demands. 
     The present invention also provides an adjustable hinge for use in a mobile phone. Through adjusting the relative position between the rotatable portion and the fixed portion of the mobile phone, an adjustable maximum opening angle can be achieved to satisfy different user demands. 
     The present invention also provides a connection method for a cylinder and a shaft, both included in the adjustable hinge, to avoid detaching the cylinder from the hinge directly during an adjusting process. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1   a  is a schematic view of a foldable apparatus; 
         FIG. 1   b  is a side view of the foldable apparatus; 
         FIG. 1   c  is a side view of the foldable apparatus; 
         FIG. 1   d  is a schematic view illustrating how an adjustable hinge works in the foldable apparatus; 
         FIG. 1   e  is another schematic view illustrating how an adjustable hinge works in the foldable apparatus; 
         FIG. 1   f  is a schematic view illustrating an adjustable hinge in accordance with an embodiment of the present invention; 
         FIG. 2  is a side view illustrating an adjustable hinge in accordance with an embodiment of the present invention; 
         FIG. 3  is a side view illustrating an adjustable hinge in accordance with another embodiment of the present invention; 
         FIG. 4  is a schematic view illustrating a ring in accordance with an embodiment of the present invention; 
         FIG. 5  is a schematic view illustrating how to prevent accidental separation of a cylinder of the present invention; and 
         FIG. 6  is a schematic view illustrating a resilient member in accordance with the embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     An adjustable hinge for use in a foldable apparatus is provided. The foldable apparatus herein can be a mobile phone. As shown in  FIG. 1   a , the foldable apparatus  10  includes a cover  102 , a body  101  and an adjustable hinge  103 . The adjustable hinge  103  connects with the cover  102  and the body  101  to allow the cover  102  and the body  101  to open or fold according to a user&#39;s demand. As shown in  FIG. 1   b , when the cover rotates, relative to the body  101 , to a fully open position, a maximum opening angle “a” is defined. As shown in  FIG. 1   c , after the adjustment by the adjustable hinge  103  (how to adjust will be elaborated below), the value of the maximum opening angle has changed to “b (b&gt;a).” Thus, the maximum opening angle can be changed to fit different requirements. 
     Referring now to both  FIGS. 1   d  and  1   e , the foldable apparatus  10  of the present invention includes a cover  102 , a body  101  and an adjustable hinge  103 . In  FIG. 1   d , the maximum opening angle of the foldable apparatus  10  is fixed. When the user wants to adjust the maximum opening angle, he has to pull the adjustable hinge along the direction X depicted in  FIG. 1   d . Then the user has to rotate the adjustable hinge  103  following the direction Y (or the opposite direction) depicted in  FIG. 1   e  to adjust the maximum opening angle. The details of the adjustable hinge  103  will be described below. 
       FIG. 1   f  is a schematic view of an adjustable hinge of an embodiment of the present invention. Now referring to  FIG. 1   f , the adjustable hinge  103  includes a fixed portion  105  and a rotatable portion  104 . The fixed portion  105  is fixedly attached to the body  101  and the rotatable portion  104  can rotate relative to the body  101 . It should be noted that the adjustable hinge of the present invention is not limited to that as shown in  FIG. 1   f.    
       FIG. 2  is a side view of an adjustable hinge in accordance with an embodiment of the present invention. As shown in  FIG. 2 , the adjustable hinge includes a fixed portion  23  and a rotatable portion  21 . The rotatable portion  21  includes a first protrusion portion  201  and defines a space  204 . The fixed portion  23  connects with the body (not illustrated). The fixed portion  23  includes a second protrusion portion  203  and defines a recess  202 . When the first protrusion portion  201  is disposed in the recess  202 , the rotatable portion  21  and the fixed portion  23  cannot have any relative movement and the maximum opening angle cannot be adjusted. When the user pulls the rotatable portion  21  out of the fixed portion  23  (along x direction depicted in  FIG. 2 ), then the first protrusion portion  201  is outside the recess  202  and the user can adjust the maximum opening angle. After the user has finished the adjustment, he only has to put the first protrusion portion  201  into the recess  202 , and then the maximum opening angle value will be fixed again. 
     Referring now to  FIG. 3 , the adjustable hinge  103  includes a cap  301 , a cylinder  302 , a shaft  304 , a ring  305 , a holder  307  and a cam  308 . The cap  301  includes a first protrusion portion  303  and the holder  307  defines a recess  309 . The first protrusion portion  303  can be disposed in the recess  309 . When the first protrusion portion  303  is disposed in the recess  309 , the maximum opening angle, defined by the cover and the body, is not adjustable. On the contrary, when the first protrusion portion  303  is outside the recess  309 , the maximum opening angle can be adjusted according to different requirements. As shown in  FIG. 3 , the cam  308  includes a second protrusion portion  310  and the ring  305  defines a space  306 . Referring to  FIG. 4 , the second protrusion portion  310  is inside the space  306 . The space  306  provides the second protrusion portion  310  with a limit room to adjust the maximum opening angle by changing the relative position of the second protrusion portion  310  in the space  306 . The size of the space  306  determines the adjusting range of the maximum opening angle. The more the second protrusion portion can move in the space  306 , the wider range the maximum angle can be adjusted. 
     As shown in  FIG. 3 , the cap  301 , the cylinder  302 , the shaft  304  and the ring  305  can rotate relative to the body  101  (these parts are functionally similar to the rotatable portion  21  as shown in  FIG. 2 ), and the holder  307  and the cam  308  are fixedly attached to the body  101  (these two parts are functionally similar to the fixed portion  23  as shown in  FIG. 2 ). 
     Referring to the embodiment as shown in  FIG. 3 , the user pulls the cap  301  and cylinder  302  out of the holder  307  (along x direction depicted in  FIG. 3 ), then the first portion  303  is outside the recess  309  and the user can adjust the maximum opening angle. After the user has finished his adjustment, he only has to put the cap  301  and cylinder  302  into the recess  309 , and then the maximum opening angle value will be fixed again. 
     Referring now to  FIG. 5 , the cylinder  302  includes a hook  503 , and one end of the shaft  304  includes a third protrusion portion  501 . The hook  503  is used to join the third protrusion portion  501  of the shaft  304  to avoid detaching the cylinder  302  accidentally from the adjustable hinge, when the user tries to pull out the cylinder  302 . In other embodiments, similar methods can provide the same function, for example by increasing the friction force between the cylinder  302  and the shaft  304 . 
     Referring back to  FIG. 2 , the fixed portion  23  connects with the body (not illustrated) by utilizing at least one latch (not illustrated) and at least one corresponding trench (not illustrated). The latch is disposed on the fixed portion  23 , and the trench is disposed on the body. However, in another embodiment of  FIG. 3 , the latch can be disposed on the holder  307  and the trench is disposed in the body. 
     In the embodiment of  FIG. 3 , the adjustable hinge of the present invention further includes a resilient member  601 . Referring to  FIG. 6 , the resilient member  601  provides a resilient force to maintain the relative position between the cam (not illustrated) and the holder (not illustrated). The adjustable hinge of the present invention can further include a sleeve  602  and a fixing ring  603  to use with the resilient member  601 . As shown in  FIG. 6 , the sleeve  602  covers the resilient member  601 , and the fixing ring  603  connects with one end of the shaft to get some support. When the resilient member  601  connects with the cam (not illustrated) along the x direction, the resilient member  601  provides a resilient force to maintain the relative position between the cam and the holder to ensure the adjustable hinge works in normal condition. 
     While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not to be limited to these embodiments. The invention is intended to cover various modifications and equivalent arrangements within the spirit and scope of the appended claims.

Summary:
An adjustable hinge device is provided for a foldable apparatus in accordance with the present invention. The foldable apparatus, such as a portable mobile phone, comprises a cover and a body connected by the hinge so as to make the cover rotatable relative to the body between a fully opened position and a fully closed position. When the cover rotates to the fully opened position, a maximum opening angle is defined. According to the relative movement between a rotatable portion and a fixed portion of the adjustable hinge, the maximum opening angle can be adjusted to fit different requirements.