Abstract:
A hinge mechanism includes a main shaft ( 2 ), a torsion spring ( 6 ) and a housing ( 8 ). The main shaft has a first shaft end ( 20 ) and an opposite second shaft end ( 21 ). The main shaft includes a stopping mechanism ( 26 ) provided at the first shaft end. The torsion spring surrounds the main shaft. The torsion spring has two ends and a substantially hollow interior. The housing is cylinder-shaped and hollow, having a first housing end and a second housing end with a shaft-receiving opening. The main shaft and the torsion spring are inserted into the housing. The stopping mechanism stops the main shaft from becoming disassembled from the housing. The main shaft is inserted into the torsion spring and received in the shaft-receiving opening of the housing. Also included is an electronic device having such a hinge mechanism. The hinge mechanism is easily manufactured and has a nice interchangeability.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention generally relates to hinge mechanisms and, more particularly, to a hinge mechanism for hinging together housings of a foldable electronic device, such as a mobile phone or a PDA (Personal Digital Assistant). 
     2. Discussion of the Related Art 
     Many mobile phones and other portable electronic devices have two housings rotatably joined by a type of hinge that allows the housings to fold upon one another. Many such foldable mobile phones have most of the electronics in one housing, called the main housing, and fewer electronics in the other housing, called the cover. Other such foldable mobile phones have all the electronics in the main housing, with the cover serving only to cover a keypad and a display of the main housing. The main housing and the cover are connected together by a hinge mechanism. A typical hinge mechanism for foldable mobile phones and other portable electronic devices incorporate a torsion spring to achieve the rotation between the main housing and the cover in order to help the device to selectably remain closed or open. 
     One such kind of hinge mechanism is disclosed in U.S. Pat. No. 6,493,542, the contents of which are hereby incorporated by reference thereto. Referring to  FIG. 1  of the present application, the hinge mechanism includes a sleeve  91 , a torsion spring  92 , and a main shaft  93 . The sleeve  91  is substantially a hollow cylinder, with an open end and an opposite closed end. Disposed proximate the opposite closed end is an end portion  912  for latching with a cover section (not shown) of a foldable mobile phone (also not illustrated). Additionally, near the opposite closed end but opposing the end portion  912  is defined a blind receiving hole  914 , with inner threads. A given finger  922 ,  924  extends from the two ends of the torsion spring  92 , respectively. The main shaft  93  has a fixing portion  932  at one end thereof and a flange  934  at another opposite end. The fixing portion  932  has outer threads defined thereon. 
     In assembly, the torsion spring  92  is received in the sleeve  91 . The finger  924  is engaged with a body section (not shown) of the foldable mobile phone. The main shaft  93  is inserted into the sleeve  91 , and the fixing portion  932  is mounted into the blind receiving hole  914  of the sleeve  91 . The hinge mechanism thus is completely assembled. The duly assembled hinge mechanism is then received in the body section of the foldable mobile phone. The end portion  912  is engaged with a cover section (not shown), and the finger  924  is operative with the body section. When the cover section is closed, the torsion spring  92  has a predetermined torsion. At the same time, the cover section is mated through a locking mechanism (not shown), such as a magnet. The magnetic force can make the cover section close to the body section. 
     When in use, the locking mechanism is released, and the cover section is opened via the torsion of the spring  92 . The structure of the hinge mechanism is simple, and the operation is convenient. However, the torsion force of the whole hinge mechanism suffers from the end portion  912  of the sleeve  91 . The end portion  912  is small and thus requires a higher strength. Furthermore, the impact force burdens the body section and the cover section. The body section and the cover section, as such, are easily worn, thereby shortening the working lifetime of the foldable mobile phone. Moreover, the body section must be specially constructed in order to permit engagement thereof with the finger  924 . Therefore, the hinge mechanism has a poor exchangeability (i.e., not readily interchangeable), which could increase the cost of the mobile phones employing such a hinge mechanism. 
     What is needed, therefore, is a new hinge mechanism that overcomes the above-described problems. 
     SUMMARY OF THE INVENTION 
     The present hinge mechanism includes a main shaft, a torsion spring, and a housing. The main shaft has a first shaft end and an opposite second shaft end. The main shaft further includes a stopping mechanism, provided at the first shaft end. The torsion spring surrounds the main shaft. The torsion spring has two ends and a substantially hollow interior. The housing is cylinder-shaped and hollow, having a first housing end and a second housing end. The first housing end thereof is open and sized to receive the torsion spring therein. The second housing end has a shaft-receiving opening sized and configured to receive the main shaft therein. The torsion spring is inserted into the housing. The main shaft is inserted into the torsion spring and received in the second opening of the housing. The stopping mechanism prevents the main shaft from becoming disassembled from the housing. 
     An electronic device includes a main housing, a cover, and the present hinge mechanism. The hinge mechanism is used to rotatably hinge the main housing and the cover. The housing and the main shaft of the present hinge mechanism respectively engage with the main housing and the cover. 
     It is unnecessary to provide any special structure within the main housing and/or the cover of the electronic device, so the electronic device is easily manufactured and assembled. In addition, the hinge mechanism has a nice exchangeability and could potentially be employed in any of a variety of situations in which it desired that a hinge be configured for selectably maintaining one of an open and closed position. 
     Other advantages and novel features of preferred embodiments of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Many aspects of the present hinge mechanism can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, the emphasis instead being placed upon clearly illustrating the principles of the present hinge mechanism. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
         FIG. 1  is an exploded, isometric view of a conventional hinge mechanism; 
         FIG. 2  is an exploded, isometric view of the present hinge mechanism, in accordance with a preferred embodiment thereof; 
         FIG. 3  is similar to  FIG. 2 , but viewed from an opposite direction; 
         FIG. 4  is an assembled, isometric view of the hinge mechanism of  FIG. 2 ; and 
         FIG. 5  is an isometric view of an electronic device employing the hinge mechanism of  FIG. 4 . 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Referring to  FIG. 2  through  FIG. 4 , a hinge mechanism  12  includes a main shaft  2 , a washer  4 , a torsion spring  6 , a housing  8  and a pin  10 .  FIG. 5 , in turn shows the hinge mechanism  12  in use within a mobile phone  100  having a main housing  14  and a cover  16 , in accordance with a preferred embodiment. The hinge mechanism  12  is shown and detailed as follows for the purposes of providing a simple description of the preferred embodiment thereof, and the embodiments thereof are not to be construed as being limited to the following description. 
     The main shaft  2  is approximately column-shaped and has a first shaft end  20  and an opposite second shaft end  21 . A fixing portion  22  and a stopping portion  24  (e.g., a circular member affixed to the main shaft  2 ) are formed at the first shaft end  20 , and a flange  26  is formed at the second shaft end  21  of the main shaft  2 . The flange  26  is beneficially in the shape of a frustum of a cone, easing its insertion through a hole  82  within the housing  8  but making it difficult to remove thereafter. A slot  28  is defined in the main shaft  2  and runs along an axis thereof. The slot  28  runs from a side of the stopping portion  24  facing the flange  26  and through the flange  26 . The fixing portion  22  is used to engage with the main housing  14  of the mobile phone  100 . The stopping portion  24  and the flange  26  are each configured for stopping/preventing the main shaft  2  from becoming disassembled from the hinge mechanism  12  or from at least sliding out of place relative to remainder of the assembly. 
     The washer  4  is approximately ring-shaped. A central hole  42  is defined in the washer  4  along a central axis thereof. The washer  4  forms two protrusions  44  and a catch piece  46  at the edge/outer periphery thereof. The protrusions  44  and the catch piece  46  are arranged symmetrically along the outer periphery of the washer  4 . A rectangular hole  462  is defined in the catch piece  46 . 
     The torsion spring  6  is formed of a piece of metal sheet. The metal sheet coils into several layers of approximate cylinders (i.e., multiple essentially cylindrical coils) to form the main portion of the torsion spring  6 . An end portion of the outside layer of the torsion spring  6  is bent into a hollow, approximately cuboid-shaped (i.e., a rectangular-parallelepiped shape) mounting portion  62 . An end of the inside layer of the torsion spring  6  coils into a holding portion  64 , which is substantially hollow and specifically configured for receiving the main shaft  2  therein. The cross-section of the holding portion  64  is “S” shaped. The central section of the holding portion  64  is a flat holding piece  642 , which extends at least part of the length of the torsion spring  6  (more advantageously, substantially, if not all, the length thereof, to promote better engagement with the slot  28  of the main shaft  2 ). The holding piece  642  engages the slot  28  of the main shaft  2 , upon insertion of the main shaft  2  into the holding portion  64  of the torsion spring  6 . The torsion spring  6  is received in the housing  8 . 
     The housing  8  is approximately in the shape of a hollow cylinder. The housing  8  has an open end  80  and a second end, which has a hole  82  therein. A hollow projection  84  is formed on the sidewall of the housing  8  along a line parallel to an axis of the housing  8 . A gap  840  is defined at the open end  80  of the projection  84 . Accordingly, the housing  8 , with its projection  84 , is appropriately configured for receiving the torsion spring  6 , with its mounting portion  62 , therein. An inserting hole  842  is defined at the opposite end of the projection  84 . A figure of the open end  80  is matingly the same as the section figure of the washer  4 . Two grooves  86  are defined at the open end  80 . Positions of the gap  840  and the grooves  86  correspond to the positions of the catch piece  46  and the protrusions  44  of the washer  4 , so that the washer  4  can be received in the open end  80  of the housing  8 . The projection  84  of the housing  8  is used to engage with the cover  16  of the mobile phone  100 . 
     The pin  10  is cuboid-shaped and has a hook  102  at one end thereof. The pin  10  is contained in the projection  84  of the housing  8  and, more specifically, is slidingly inserted into the mounting portion  62  of the torsion spring  6 . The hook  102  of the pin  10  thus engages with the one end of the projection  84  where the inserting hole  842  is located. 
     When assembling the hinge mechanism  12 , firstly, the torsion spring  6  is placed into the housing  8 , and the mounting portion  62  is directed into the projection  84 . Next, the washer  4  is mounted at the open end  80  of the housing  8 . The catch piece  46  and the protrusions  44  of the washer  4  are respectively accepted in the gap  840  and the grooves  86  of the housing  8 . Then, the main shaft  2  is sequentially run through the central hole  42  of the washer  4 , the holding portion  64  of the torsion spring  6 , and the hole  82  of the housing  8 , with the holding piece  642  of the torsion spring  6 , in turn, running through the slot  28  of the main shaft  2 . During the process of running through the hole  82  of the housing  8 , the flange  26  deforms and is locked at the opposite end of the open end  80  of the housing  8  because a maximum diameter of the flange  26  is larger than that of the hole  82 . The stopping portion  24  is stopped by the washer  4  as a diameter of the stopping portion  24  is larger than that of the central hole  42  of the washer  4 , thereby helping to properly position the main shaft  2 . Finally, the pin  10  is sequentially inserted into the inserting hole  842  of the housing  8 , the mounting portion  62  of the torsion spring  6 , and the rectangular hole  462  of the washer  4 . The pin  10  is stopped at the side of the inserting hole  842  by the hook  102 . The hook  102  is fixed on the housing  8  by, e.g., gluing, plastering, soldering, or melting/welding. The hinge mechanism  12  is thereby assembled, as best shown in  FIG. 4 . The mounting portion  62  of the torsion spring  6  is fixed to the housing  8 , and the holding portion  64  of the torsion spring  6  is fixed to the main shaft  2 . 
     Referring to  FIG. 5 , the hinge mechanism  12  is used in the exemplary mobile phone  100  having the main housing  14  and the cover  16 . The assembled hinge mechanism  12  is assembled to connecting portions (not shown) of the main housing  14  and the cover  16 . The housing  8  engages with the cover  16  by the projection  84 . The housing  8  can rotate together with the cover  16  relative to the main housing  14 . The main shaft  2  engages with the main housing  14  by the fixing portion  22 . The mounting portion  62  of the torsion spring  6  is fixed relative to the cover  16 , and the holding portion  64  of the torsion spring  6  is fixed relative to the main housing  14 . When the cover  16  is closed, the torsion spring  6  is in a twisted state, and the cover  16  is fixed to the main housing  14  by a fixing structure or a magnetic mechanism. The hinge mechanism  12  is in an unsteady state, and the cover  16  is apt to open relative to the main housing  15 . 
     When the cover  14  needs to be opened, the fixing structure or magnetic mechanism is manually released. The holding portion  64  of the torsion spring  6  is released and rotates due to the resilient force of the torsion spring  6 . Therefore, the cover  16  rotates together with the housing  8 , since the housing  8  is fixed relative to the mounting portion  62 . As such, the cover  16  is opened. The torsion spring  6  is completely released, and the cover  16  stops rotating. The cover  16  can also be opened to a prearranged angle, limited by a structural limitation of the main housing  14  and the cover  16 . When closing the cover  16 , the cover  16  is rotated manually and then fixed to the main housing  14  by the fixing structure or the magnetic mechanism. 
     In alternative embodiment, the pin  10  can be omitted, and the holding portion  64  of the torsion spring  6  could fixed to the housing  8  directly by pasting/gluing, soldering, or melting, for example. The slot  28  of the main shaft  2  can also be omitted, so long as the holding portion  64  is eliminated and the main shaft  2  is then otherwise attached to the torsion spring  6  (e.g., adhesively or metallurgically). The washer  4  also can be omitted. The torsion spring  6  can be of another form, such as a column helical spring, as long as it can attach to and/or engage with the housing  8 . The flange  26  of the main shaft  2  can be replaced with another stopping mechanism, such as a ring or a nut, arranged at the second shaft end  21  of the main shaft  2 , in order to stop the main shaft  2  from becoming disassembled from the housing  8 . As a further alternate, it is recognized that the hinge mechanism  12  could have potential applications beyond foldable electronic devices (e.g., cabinet doors), and such uses are considered to be within the scope of use of this hinge assembly  12 . 
     It is believed that the embodiments and their advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the examples hereinbefore described merely being preferred or exemplary embodiments of the invention.