Patent Publication Number: US-2005138771-A1

Title: Hinge

Description:
FIELD OF THE INVENTION  
      The present invention relates to hinges and more particularly to a hinge for a cellular phone that reduces rotational wear via implementation of cam mechanism acting on a sleeve and a cam follower of the hinge.  
     BACKGROUND OF THE INVENTION  
      Cellular phones are advantageous for being compact and portable. Typically, a person places a cellular phone in his/her pocket, handbag, briefcase, or the like whilst on the move. However, it is often that a person inadvertently presses the keys of the cellular phone since they are provided on a front surface of the phone body. Some cellular phone manufacturers have developed key lock mechanisms for the prevention of inadvertent key pressing. However, a cellular phone having such a key lock mechanism is inconvenient.  
      A solution to the above problem is to incorporate a flap cover hinged to the body of a cellular phone. A great number of different hinges have been developed. For example, U.S. Pat. No. 5,697,124 discloses a hinge mechanism for foldable electronic apparatus in which a hinge housing including internal components (e.g., hinge shaft, cam follower, hinge arm, coil spring, and hinge cover) are provided. Guide slit and hooking grooves, formed on the hinge housing, are adapted to cooperate to control the rotational angle of the cam follower about the hinge shaft to open or close a flip-cover. It is difficult to manufacture guide slit and grooves on the hinge housing. Also, the hinge housing is relatively large and the hinge housing has a thicker surface for maintaining its structural integrity. Another prior art U.S. Pat. No. 5,724,683 discloses a hinge mechanism for supporting the seat of the seat lid of a toilet bowl in which the shaft, hinge pin, cam mechanism, and spring are provided in a cylindrical case. Also, components including pads, screws, and O-ring are provided. The hinge pin has a means to rotate with the shaft. Further, the cam includes a slider mounted on the shaft in the case so as to turn together with the shaft. It is disadvantageous for being structurally complex. Also, such hinge mechanism is required to install in a pair when incorporated in a cellular phone. As a result, a reduction in size is made impossible. Still another prior art U.S. Pat. No. 5,937,062 discloses a hinge module for mounting a flip onto a portable telephone set in which a first cam, a second cam, a guiding member, an elastic member, and a retractable member are provided for controlling the opening or closing of a flip. It is advantageous for the reduction of the hinge module. However, there is no housing provided as protection. As such, it is difficult to position and assemble. Also, it is not structurally robust and has a shortened period of use.  
      Thus, it is desirable to provide a hinge having a reduced number of components while maintaining its structural integrity in order to overcome the above drawbacks such as complex construction and poor strength of the prior art.  
     SUMMARY OF THE INVENTION  
      It is an object of the present invention to provide a hinge for cellular phone that reduces rotational wear and increases operating stability. This can be attained by implementing a sleeve having a plurality of slots and a cam follower having a plurality of interdental ridges to engage with the slots.  
      To achieve the above and other objectives, the present invention provides a hinge mounted in a joint on the flap cover and the body of a cellular phone. The hinge comprising a sleeve fixed to the body, the sleeve including a plurality of longitudinal slots on an internal wall; a cam follower including a plurality of longitudinal ridges on an outer surface corresponding to the slots so that turning the cam follower will move the ridges either downward to a steady position or upward to a non-steady position along the slots. Having a cam means fixing the flap cover, the cam means including a bottom cavity and two cam members at opposite sides of the cavity wherein the cavity and the cam members are adapted to engage with the raised members and the recess respectively so that the cam adapts to turn either to an first position or a second position with respect to the sleeve; a spring in the sleeve, the spring having one end pressed against the bottom of the sleeve and the other end against the cam follower so to maintain the cam and the cam follower in the steady position; and a shaft having one end fixed to the cam means so as to turn either from the first position to the second position or from the second position or the first position with the cam follower being moved either downward to a steady position or upward to a non-steady position with respect to the sleeve, and the other end passing through the cam follower and spring to control the movement of the cam follower.  
      The above and other objects, features and advantages of the present invention will become apparent from the following detailed description provided with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a perspective view of a preferred embodiment of a hinge according to the present invention;  
       FIG. 2  is an exploded view of the present invention;  
       FIGS. 3A and 3B  are cross-sectional views of closing and opening operation of the hinge respectively for the illustration of one article incorporating the hinge pivoting about the other coupled article; and  
       FIG. 4  illustrates a hypothetical view of the hinge mounted in a joint of a flap cover and a body of a cellular phone. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      Referring to  FIGS. 1 and 2 , there is shown a hinge constructed in accordance with the invention. The hinge comprises a sleeve  11  including two opposite rectangular flats  111  on the circumferential surface, the flats  111  being adapted to fasten at a joint of two articles as detailed later, a plurality of longitudinal slots  113  on an internal wall, a first opening  112  at one end, and a second opening  114  at the other end, the second opening  114  having a diameter much smaller than that of the first opening  112 ; and a cam follower  12  including a recess  123  at one end, a hollow cylindrical protrusion  124  at the other end, two raised members  122  at opposite sides of the recess  123 , and a plurality of longitudinal ridges  121  on the outer surfaces of the raised members  122 , the ridges  121  fitting in the slots  113 . Turning the cam follower  12  causes the ridges  121  to move downward to a steady position or upward to a non-steady position along the slots  113  (indicated by dash line of  FIG. 3A ). That is, the cam follower  12  has a steady position and a non-steady position with respect to the sleeve  11  as described in detail later.  
      The hinge further comprises a cam device  13  including two opposite rectangular flats  131  on the outer surface, the flats  131  being adapted to fasten at a joint of two articles as detailed later, a flat top surface  135 , a longitudinal cylindrical bore  134  open at both ends, a bottom cavity  133 , and two cam members  132  at opposite sides of the cavity  133 . The cavity  133  and the cam members  132  are adapted to engage with the raised members  122  and the recess  123  respectively. The cam device  13  has a diameter slightly smaller than that of the first opening  112  so as to fit in the sleeve  11 . As indicated by the dashed line, the cam device  13  is adapted to dispose in either the first or second positions with respect to the sleeve  11  by turning. Also, the turning force of the cam device  13  will exerts evenly onto the ridges  121  and the mated slots  113 . As a result, the cam device  13  is neither subject to excessive wear nor deformity.  
      The hinge further comprises a helical spring  14  having one end pressed against the second opening  114  and the other end put on the protrusion  124  as the helical spring  14  mounted in the sleeve  11  (as indicated by the dashed line). The provision of the helical spring  14  aims at maintaining both the cam device  13  and the cam follower  12  in the steady position. The hinge further comprises a shaft  15  formed of metal. The shaft  15  comprises a circular top member  151 , a neck  152  engaged with edges of the bore  134 , a main shank  153 , and a cylindrical bottom projection  154  having a diameter smaller than that of the shank  153 . The shaft  15  is passed through the helical spring  14 , the cam follower  12 , and the cam device  13  and has its top member  151  flush with the top surface  135  and bottom projection  154  coming from the second opening  114  to tightly couple with a washer  16 . The cam follower  12  and cam device  13  together with the helical spring  14  and shaft  15  are mounted in the sleeve  11  so that the hinge can be operated by turning the cam device  13  and thus the cam follower  12  as detailed later.  
      Referring to  FIGS. 3A, 3B , and  4 , operations of the invention for opening and closing a flap cover  17  with respect to a body  18  of a cellular phone will now be described in detail below. In a first position, the flap cover  17  is closed onto the body  18  with both the cam device  13  and the cam follower  12  held in place (see  FIG. 3A ). Turning the cam device  13  (i.e., turning the cam members  132  and the cavity  133 ) with respect to the cam follower  12  (i.e., the recess  123  and the raised members  122 ) will cause both the cam device  13  and cam follower  12  to move to a second position (see  FIG. 3B ). That is, the flap cover  17  is pivoted to form an angle with respect to the body  18  in an opened state.  
      Referring to  FIG. 4  again, in an exemplary example of the invention the hinge is mounted in a joint of the flap cover  17  and the body  18  of a cellular phone. As shown, the flats  111  of the sleeve  11  are fixed to the body  18  and the flats  131  of the cam device  13  are fixed to the flap cover  17  respectively. Hence, a user can either open the flap cover  17  (i.e., in the second position) or close the flap cover  17  (i.e., in the first position) with respect to the body  18 .  
      While the invention herein disclosed has been described by means of specific embodiments, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope and spirit of the invention. Accordingly, the appended claims are intended to cover all of the aforementioned.