Abstract:
A wide-angle double-hinge structure to allow an electronic device to flip at different angles includes a coupling plate, a resistant hinge and a cam hinge. The double-hinge structure couples a first chassis and a second chassis of the electronic device to enable users to selectively flip in an ordinary notebook computer operating condition or a back-to-back operating condition according to their preference. Thus the users can selectively perform input operation in a handheld or desktop fashion.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a wide-angle double-hinge structure and particularly to a double-hinge structure to enable an electronic device to flip at different angles to facilitate user input operation in a handheld or desktop fashion. 
         [0003]    2. Description of the Prior Art 
         [0004]    The prevailing trend of computer development increasingly focuses on portability. Most computer makers invest heavily aiming to make computer usable anywhere anytime. Power lasting time and performance also are important factors. Meeting these ends has to rely on power-saving elements developed by semiconductor manufacturers and high capacity batteries developed by battery makers. To overcome the constraint of using site has to rely on system designers. Most notebook computers at present adopt a foldable two-piece chassis. One piece is for a computer screen and other piece is for a keyboard. The two pieces can be unfolded substantially perpendicular to each other to be rested on a table for use. But it is not convenient for handheld operation. The model for handheld operation mostly is tablet computer which has the screen located on the chassis. When in use a user holds the computer with one hand and holds a stylus with other hand to tick a function key or do writing on the screen. 
         [0005]    Although the tablet computer makes handheld operation easier, many important computer operations relate to text entry. As the tablet computer uses the stylus as the main input means, it is slower and takes more efforts than the conventional keyboard operation. Hence while the portability improves, input operation becomes a constraint. As a result, the tablet computer is not well accepted on the market. It mostly is limited to special applications, such as doctor&#39;s touring wards, warehouse stock taking and the like that require merely ticking of options without much text entry. 
         [0006]    To facilitate input operation, some tablet computers provide a fan-type keyboard table on a touch screen to enable users to hold the computer with two hands and depress keys with two thumbs. As the two hands have to hold the computer, the moving range of the thumbs is limited. Moreover, the thumbs are naturally clumsier in operation. Hence operation speed is slower than the conventional real keyboard. 
         [0007]    There is another design which adopts a slidable real keyboard. When there is a need to do a great amount of text entry, the rear keyboard hidden inside the chassis can be moved out. However, its operation approach also is same as the one with the touch keyboard table on the screen, and require user&#39;s fingers other than the thumbs to hold the computer, and input operation is done through the clumsy thumbs. As the handheld portion is the keyboard, and the screen is extended rearwards, the gravity center of the computer is located outside the two hands. Holding the computer is difficult and cannot last for a long duration for the general users. 
       SUMMARY OF THE INVENTION 
       [0008]    To resolve the aforesaid problems the operation keys and the screen have to be positioned back to back, with the keyboard table displayed on the screen mapping the keys at the back side, and each key has to be equipped with a tactile sensor so that user&#39;s eyes can see the keyboard table on the screen to determine the key layout and finger positions at the back side, then the rest fingers other than the thumbs can be freed to perform operation on the keys. 
         [0009]    But such a novel operation interface and method could hinder user&#39;s contact. This is especially troublesome for novices. Many people even are discouraged to buy or use. To provide two alternative use methods at the same time to allow users to make selection will be a great incentive to reduce use&#39;s reluctance. One is like the conventional notebook computer operation approach that allows a screen  91  to be unfolded at an angle Θ 1  about 90 degrees, and has a keyboard  921  located above a body  92  (referring to  FIG. 1 ). Such an operation method is same as the conventional notebook computer and used to by users without problems. The only handicap is that it needs a table top when in use. 
         [0010]    To overcome the shortcomings of the conventional techniques, the screen must be swivelable at a wide angle greater than 270 degrees so that user&#39;s fingers other than the thumbs can hold one side where the keys are located while the screen faces the user, and the body and the screen can be folded at an angle no greater than 90 degrees. Therefore it is an object of the invention to provide a wide-angle double-hinge structure that includes a coupling plate, a resistant hinge and a cam hinge. The double-hinge structure couples a first chassis and a second chassis of an electronic device to allow users to selectively flip to become an ordinary notebook computer operation condition, or a back-to-back operation condition according to user&#39;s preference. Therefore user can do input operation on a table top or in a handheld manner as desired. 
         [0011]    The foregoing, as well as additional objects, features and advantages of the invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  is a schematic view of a conventional portable electronic device in a use condition. 
           [0013]      FIG. 2  is a perspective view of an embodiment of the invention. 
           [0014]      FIG. 3  is a perspective view of the invention. 
           [0015]      FIG. 4  is an exploded view of the invention. 
           [0016]      FIG. 5  is a sectional view of the invention. 
           [0017]      FIG. 6  is schematic view-1 of an embodiment of the invention in an operating condition. 
           [0018]      FIG. 7  is schematic view-2 of an embodiment of the invention in an operating condition. 
           [0019]      FIG. 8  is a sectional view of an embodiment of the invention. 
           [0020]      FIG. 9  is schematic view-3 of an embodiment of the invention in an operating condition. 
           [0021]      FIG. 10  is schematic view-4 of an embodiment of the invention in an operating condition. 
           [0022]      FIG. 11  is another sectional view of an embodiment of the invention. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0023]    Referring to  FIGS. 2 through 6 , the wide-angle double-hinge structure according to the invention includes a coupling plate  1 , a resistant hinge  2  and a cam hinge  3  that are installed on an electronic device A to couple a first chassis  4  and a second chassis  5 . The first chassis  4  has a display screen  41 . The second chassis  5  has at least one key zone  51  which may be a touch key. 
         [0024]    The coupling plate  1  has a first retaining hole  11  and a second retaining hole  12  that are non-circular through holes to retain respectively the resistant hinge  2  and the cam hinge  3 . 
         [0025]    The resistant hinge  2  has a fastening axle  22  at one end fastened to the coupling plate  1  and a movable sleeve  21  at another end with at least one fastening hole  211  formed thereon to be fastened to one end of the first chassis  4 . The sleeve  21  has an axle  212  on other end to be inserted by a bolt  221  of the fastening axle  22 . The fastening axle  22  has a retaining portion  222  at one side to be confined in the first retaining hole  11  of the coupling plate  1 . 
         [0026]    The cam hinge  3  has one end fastened to the coupling plate  1  and a stem  31  running through an anchor plate  32 , a first element  33 , a second element  34  and a spring  35  to be fastened by a nut  36 . 
         [0027]    The stem  31  runs through the second retaining hole  12  of the coupling plate  1  and has a screw thread section  311  on one end and a polygonal section  312  to be confined in the second retaining hole  12  to be driven together with the coupling plate  1 . 
         [0028]    The anchor plate  32  has a first bracing plate  321  with an aperture  3211  and an anchor hole  3212  formed thereon, and a second bracing plate  322  perpendicular to the first bracing plate  321  to be fastened to one end of the second chassis  5 . 
         [0029]    The first element  33  has a circular through hole  331  to be run through by the stem  31  and a first cam action surface  332  on one side and a latch stub  335  on another side  334  to be wedged in the anchor hole  3212 . 
         [0030]    The second element  34  has a rectangular hole  341  run through by the stem  31  to be driven together, and a second cam action surface  342  on one side to form interaction with the first cam action surface  332  of the first element  33 . 
         [0031]    The spring  35  pushes the second element  34  in regular conditions. 
         [0032]    The nut  36  is fastened to the screw thread section  311  of the stem  31  to confine the elements set forth above. It also can adjust the elastic force of the spring  35  pushing the second element  34  to form a resistant force when the second element  34  tries to rotate. The resistant force is slightly greater than the rotation resistant force of the resistant hinge during rotating. 
         [0033]    By means of the construction set forth above the invention provides two types of use approaches to users. One is like the conventional notebook computer that is flappable at a maximum angle about 180 degrees (referring to  FIGS. 6 ,  7  and  8 ). During flipping, first, unfold the first chassis  4 ; the fastening axle  22  of the resistant hinge  2  serves as the axis of the flipping for a first stage, namely the sleeve  21  is turnable while the fastening axle remains still so that the first chassis  4  can be freely swiveled between 0-180 degrees (preferably between 90-130 degrees). Thereby the key zone  51  on the second chassis  5  can be used like a conventional notebook computer, or the display screen  41  on the first chassis  4  can be looked at like the conventional one. Another use approach is to flip the first chassis  4  more than 270 degrees so that the first chassis  4  and the second chassis  5  are formed in a back-to-back manner (referring to  FIGS. 9 ,  10  and  11 ). During flipping, first, swivel the first chassis  4 , the fastening axle  22  of the resistant hinge  2  serves as an axis, and the first chassis  4  is swiveled over 180 degrees and can be continuously swiveled downwards. Meanwhile, the turning force is greater than the force of the spring  35  pushing the second element  34  so that the stem  31  becomes the swiveling center, and also becomes the axis of a second stage swiveling to drive the stem  31  and the second element  34  (referring to  FIG. 11 ). The second cam action surface  342  slides on the first cam action surface  332  and moves to an apex h. Hence the first chassis  4  can continuously swivel about the cam hinge  3  approximately 180 degrees. As a result the total flipping angle can reach at least between 270 degrees and 360 degrees. Thus the first chassis  4  and the second chassis  5  are formed in the back-to-back manner to be used as a tablet computer. The first and second chassis  4  and  5  can be held by hands to do input operation. 
         [0034]    As a conclusion, by means of the double-hinge structure of the invention, users can have two alternatives when in use. One is like, the conventional notebook computer, and another one is to flip the screen more than 270 degrees to make the keyboard and the screen in a back-to-back manner. Hence user can spend less time of trials and errors in learning new operation interfaces. It can effectively overcome the shortcomings of the conventional techniques. 
         [0035]    While the preferred embodiments of the invention have been set forth for the purpose of disclosure, modifications of the disclosed embodiments of the invention as well as other embodiments thereof may occur to those skilled in the art. Accordingly, the appended claims are intended to cover all embodiments which do not depart from the spirit and scope of the invention.