Patent Abstract:
A portable electronic device ( 10 ) such as a mobile phone comprises two body parts ( 12, 14 ) moveably connected by hinges ( 16 ). Each hinge comprises a shaft part ( 22 ) and a housing part ( 20 ), the parts being relatively moveable about a common axis of rotation. The shaft part has a shaft pin ( 28 ) lying on the common axis of rotation and a leg ( 24 ) extending laterally with respect to the shaft pin. The housing part has an groove ( 36, 38 ) and a bore ( 32 ), the bore co-operating with the shaft pin and the groove engaging with the leg to restrain the shaft part from rotational movement. The shaft part is moveable relative to the housing part between a first position in which the leg is engaged with the groove and a second position in which the leg is not engaged with the groove.

Full Description:
FIELD OF THE INVENTION 
     The invention relates to hinges. It is particularly, but not exclusively, related to hinges used in electronic devices. In one embodiment, it relates to hinges used in portable electronic devices. 
     BACKGROUND OF THE INVENTION 
     Many types of electronic devices are known. Portable electronic devices include mobile telephones, personal digital assistants (PDAs) and portable computers such as laptops. As technology improves, it is desired to include more functions in such devices. These functions may include messaging, for example e-mails and SMS (short message service), and entry of various types of information which are useful for a user to be able to access, such as address and calendar information. To provide access to these functions, the devices often comprise user interfaces such as displays and full alphanumeric keyboards or touch-sensitive screens. 
     It may not be necessary for the complete user interface to be available all of the time. Therefore, some of these devices are foldable so that at least part of the user interface can be stored away when it is not required. In the case of a laptop, it is typically provided in a two-part form connected by hinges having a display in one part and a keyboard in another part. In the case of a multi-function device such as a combined mobile telephone/PDA, there are occasions when a full alpha-numeric keyboard is needed, for example when composing messages or editing text, and other occasions when it is not needed, for example when it is being used as a telephone. An example of such a device is the Nokia® 9110 Communicator. 
     FIG. 1 shows a prior art mobile device  10 . The mobile device  10  comprises a body part  12  and a cover part  14  which are moveable between a configuration in which the mobile device is open (unfolded) and a configuration in which the mobile device is closed (folded). The body part  12  and the cover part  14  are connected by a pair of hinges  16 . The body part  12  comprises necessary control electronics to enable the mobile device  10  to carry out telephony and PDA functions and, on an inner surface which faces the cover part  14  when the mobile device  10  is closed, a full keyboard. The keyboard is used in operation of the mobile device  10  as a PDA and in other operations. The cover part  14  comprises a conventional telephone interface on an outer surface and, on an inner surface which faces the body part  12  when the mobile device  10  is closed, a display. The cover part also comprises an antenna for transmission and reception of radio signals. 
     Since these devices are usually opened to present a user interface to a user, it is convenient if they can be held open at one or more particular angular configurations. To provide this ability, hinges are used having a suitable stiffness to resist rotation. It is difficult to maintain this ability after thousands or even tens of thousands of openings since wear tends to reduce the stiffness. Although it is possible to provide additional locking means to hold the device in any desired angular configuration (including locking the device in a closed configuration), having such locking means requires additional parts which results in additional weight and space. This is often not desirable since these devices are typically portable and should be lightweight and compact. 
     The hinge  16  used in the device  10  is shown in FIG.  2 . The hinge  16  comprises a first hinge pin element  220  attached to the body part  12  and a second hinge pin element  221  attached to the cover part  14 . The hinge pin elements are fixed against rotational movement relative to their respective parts. The first hinge pin element  220  and part of the second hinge pin element  221  are contained in a common hinge pin housing (not shown). An end  222  of the first hinge pin element  220  is provided with a tab  223  and an end  224  of the second hinge pin element  221  is provided with a slot  225 . The hinge pin elements abut at their respective ends so that the tab  223  is received in the slot  225 . The first hinge pin element  220  is spring-biased by a spring  226  so that the tab  223  is pressed into the slot  225 . This keeps the body part  12  and the cover part  14  held relatively to each other. 
     When the cover part  14  and the body part  12  are moved about the hinge  16  relatively to each other, the tab  223  is forced out of the slot  225 , the first hinge pin element  220  moves against its spring-biasing and the hinge pin elements rotate relatively to each other. 
     SUMMARY OF THE INVENTION 
     According to a first aspect of the invention there is provided a hinge comprising a shaft part and a housing part, the parts being relatively moveable about a common axis of rotation, the shaft part having a first portion lying on the common axis of rotation, the first portion carrying a bearing surface, and a second portion extending radially beyond the bearing surface of the first portion, the housing part having an engagement surface and a hinge surface, the hinge surface cooperating with the bearing surface of the first portion and the engagement surface engaging with the second portion to restrain the shaft part from rotational movement, the shaft part being moveable relative to the housing part between a first position in which the second portion is engaged with the engagement surface and a second position in which the second portion is not engaged with the engagement surface. 
     In a hinge according to the invention, it is not necessary to provide separate parts, such as a latch, to provide a locking function since this is provide by the interrelation between the shaft part and the housing part. Therefore, the hinge can be provided in a miniature form relatively straightforwardly. 
     Preferably the bearing surface is spaced apart from the common axis of rotation in radial directions. Preferably different parts of the bearing surface are spaced from the common axis of rotation by the same distance. In this case, the first portion has a round cross-section. 
     Preferably the second portion extends laterally with respect to the common axis of rotation. 
     Preferably the hinge surface encloses the first portion. Preferably the hinge surface does not enclose the second portion. Preferably the hinge surface does not enclose the engagement surface. 
     Preferably, in the second position, the shaft part is not restrained from rotational movement. Preferably in this position the first portion is acted upon by a biasing force in a first direction parallel to the common axis of rotation. Preferably in moving from the first position to the second position, the second portion is displaced axially in a second direction opposite to the first direction. 
     Preferably the first portion and the second portion meet at a junction and are disposed in an angular relationship. Most preferably, they are disposed at right angles to each other. This disposition may not be exactly equal to 90°. It may be slightly more or slightly less. It may vary as the shaft part and the housing part move relatively to each other. In another embodiment, the first portion and the second portion meet at an acute or an obtuse angle. Preferably the first and second portions are integrally formed. They may comprise a bent wire. A wire can be bent easily to fit into small hinges. Clearly, this is also inexpensive. 
     Preferably the shaft part comprises spring biasing means to provide the biasing force. Preferably the biasing force is provided by energy stored when the first and second portions are moved relatively to each other. Preferably the hinge surface does not enclose the spring biasing means. 
     Preferably the shaft part comprises a pair of first portions. Preferably the shaft part comprises a pair of second portions. The second portions may be substantially parallel. Preferably the second portions are connected together by a connecting portion. Preferably the first portions extend from the second portions away from each other. Alternatively the first portions extend from the second portions towards each other. The second portions may lie on the same axis. They may both lie on the common axis of rotation. 
     Preferably the housing part comprises a pair of hinge surfaces. Each of the hinge surfaces may co-operate with the bearing surfaces of the pair of the first portions. 
     Each hinge surface may be associated with a pair of engagement surfaces. This pair of engagement surfaces may be provided to restrain the second portion at two separate angular orientations of the shaft. The angular orientations may be separated by an angular separation of 120°. Alternatively, the angular separation may be another value such as 90° or 180°. Each hinge surface may be associated with more than two engagement surfaces to provide more than two restraining angular orientations. 
     Preferably the or each engagement surface has a profile which is complementary to that of a least a part of the bearing surface of the first portion which it restrains. Alternatively, the profile is not complementary so that there is limited contact between the or each engagement surface and the first portion. The or each engagement surface may be provided by a groove having a pair of walls and a bottom. The or each engagement surface may comprise a wall of the groove. In this embodiment, restraining of the shaft part occurs by the first portion being pressed into the groove by the biasing force. In order for the shaft part to move rotationally, the first portion needs to move out of the groove. The depth of the groove may determine the amount of restraining force provided by engagement between the engagement surface and the first portion. A deeper groove may provide a greater restraining force. The angle of the groove wall may determine the amount of restraining force provided to the first portion. The restraining force may be determined by factors such as the length or the thickness of the second portion. 
     According to a second aspect of the invention there is provided an electronic device comprising a first body element and a second body element connected by a hinge according to the first aspect of the invention. 
     The hinge may enable the body elements to move relatively to each other so that the device may be opened and closed. Preferably the shaft part is fixed to one body element and the housing part is fixed to another body element. 
     Preferably the device is portable. Preferably the device is selected from a group consisting of a mobile station, a mobile telephone, a mobile communicator, a personal digital assistant or a mobile computer such as a laptop. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     An embodiment of the invention will be described with reference to the accompanying drawings in which: 
     FIG. 1 shows a mobile device according to the prior art; 
     FIG. 2 shows a hinge prior according to the prior art; 
     FIG. 3 shows a hinge according to the invention in a disassembled state; 
     FIG. 4 shows the assembled hinge in a closed position; 
     FIG. 5 shows the assembled hinge in an open position; 
     FIGS. 6 a  to  6   d  show different hinge configurations; 
     FIGS. 7 a  and  7   b  show details of different hinge embodiments; 
     FIGS. 8 a  and  8   b  show details of different hinge embodiments; 
     FIGS. 9 a  and  9   b  show details of different hinge embodiments; 
     FIG. 10 shows detail of another hinge embodiment; and 
     FIG. 11 shows yet another hinge embodiment; and 
     FIG. 12 shows still yet another hinge embodiment. 
    
    
     DETAILED DESCRIPTION 
     FIG. 3 shows a hinge  16  according to the invention. It is shown in a disassembled state in order to present its features and its construction clearly. The hinge  16  is to be used in a mobile device according to FIG. 1 described above. The hinge  16  comprises an elongate hinge housing  20  and a co-operating hinge shaft element  22 . The hinge shaft element  22  is generally U-shaped having two parallel legs  24 . The legs  24  are connected at one end by a curved portion  26 . Located at the other end of the legs  24  are oppositely extending hinge shafts  28 . 
     The hinge housing  20  comprises polymeric material, such as an injection moulded plastic. The material is hard-wearing enough to resist wear caused by movement of the hinge shaft element  22 . 
     The hinge shaft element  22  is formed out of a single piece of metal wire which is bent into shape. Spring steel wire is suitable. Once it has been formed, the hinge shaft element  22  can be elastically deformed by pushing the hinge shafts  28  towards each other. In effect, the hinge shaft element  22  is a spring. The hinge shafts  28  co-operate with the hinge housing  20 . The hinge housing  20  comprises an entry part  30  into which the hinge shaft element  22  is inserted and a pair of bore holes  30  for receiving each of the hinge shafts  28 . The boreholes  32  are located at opposite ends of the hinge housing  20 . Each bore hole  32  is associated with a contact surface  34  over which ends of the legs  24  ride as the hinge shaft element  22  moves in relation to the hinge housing  20 . The contact surfaces  34  each comprise a pair of grooves  36  and  38  separated by a flat surface  40 . The entry part  30  is provided with a pair of sloping faces  42  and  44  which help in locating the hinge shafts  28  in the bore holes  32  as will be described below. 
     On assembly, the hinge shaft element  22  is pushed, curved portion  26  first, into the entry part  30 . The hinge shafts  28  engage the sloping faces  42  and  44  and they are pushed closer together as the hinge shaft element  22  is pushed further into the entry part  30 . When the hinge shafts  28  reach a position level with the bore holes  32 , elastic energy stored by the hinge shaft element  22  pushes the hinge shafts  28  into place in the bore holes  32  and the hinge shaft element  22  snaps into place. It may be preferred for the hinge shaft element  22  to have a relaxed, undeformed, state in which it is wider at the ends of its legs  24  than the separation of corresponding opposing pairs of grooves. In this case, when the hinge shaft element  22  is snapped into place and the ends of the legs  24  are located in the grooves, elastic energy remains stored in the hinge shaft element  22  resulting in a biasing force being applied to the hinge shafts  28 . 
     Once assembled the hinge can move between two locked configurations as shown in FIGS. 4 and 5. In moving, the hinge shaft element  22  moves about a common axis of rotation which runs through the boreholes  32  and through the hinge shafts  28 . 
     FIG. 4 shows the assembled hinge  16  in a closed position in which the legs  24  are received and held in the grooves  36 . The hinge housing  20  is fixed to the body part  12  of the mobile station and the curved portion  26  is fixed to the cover part  14 . The body part  12  is not shown. Only part of the cover part  14  is shown. It can be seen that the curved portion  26  is located in a slot which extends around a former. A hole located in the former can receive a screw with is used to mount the hinge  16  onto the cover part  14 . 
     FIG. 5 shows the assembled hinge  16  in an open position in which the legs  24  are received and held in the grooves  38 . 
     In moving the hinge  16  from the closed position to the open position, force is applied to the hinge shaft element  22  to move it about the common axis of rotation. This forces the ends of the legs  24  located in the grooves  36  to ride up side walls of the grooves  36  so that the hinge shafts  28  are pushed closer together against the biasing force which acts along the common axis of rotation. As the hinge shaft element  22  is moved, the ends of the legs  24  come completely out of the grooves  36  so that they rest on the flat surfaces  40 . This increases the biasing force applied to the hinge shafts  28 . The legs  24  then ride across the flat surface  40  until, in their progress, they arrive at the location of the grooves  38  and are pushed into them. 
     It may be preferred for the hinge shaft element  22  to have a relaxed, undeformed, state in which it is as wide at the ends of its legs  24  as the separation of corresponding opposing pairs of grooves. In this case, there is no biasing force when the ends of the legs  24  are located in the grooves. However, it is still desirable for a biasing force to be applied when the ends of the legs  24  rest on the flat surfaces  40  in order that the ends of the legs be pushed into the grooves  36  and  38 . 
     It can be understood that a certain amount of force is required to cause the ends of the legs  24  out of the grooves  36  and  38 . Accordingly, the engagement of the ends of the legs  24  with the grooves  36  and  38  creates a locking force which serves to hold the hinge shaft element  22  in a particular orientation and thus likewise hold the body part  12  and the cover part  14  in a particular orientation. 
     To assist in understanding the preceding description, FIGS. 6 a  to  6   d  show part of a different hinge embodiment having a plurality of hinge configurations. The principles involved in operation of this hinge embodiment are the same as those involved in operation of the hinge embodiment previously described. The hinge embodiment of FIGS. 6 a  to  6   d  comprises a hinge housing  60  and a hinge shaft  62  carried by a leg  64 . The hinge shaft  62  locates in a borehole  66 . Grooves  67  and  68  are located on opposite sides of the borehole  66  corresponding to the hinge shaft  62  occupying rotational orientations separated by 180°. The grooves  67  and  68  are separated by a flat surface  69 . As can be seen, the hinge housing  60  is presented only in a fragmentary view which shows its significant features. 
     FIG. 6 a  shows the hinge shaft  62  being inserted into the borehole  66 . FIG. 6 b  shows a first locking position in which the end of the leg  64  is located in the groove  67 . In common with the previous description, it is held in place by a biasing force. FIG. 6 c  shows the leg  64  moving from the first locking position. A turning force applied to the leg  64  forces its end to come out of the groove  67  and the hinge shaft  62  to move relatively to the hinge housing  60  in a direction opposite to the biasing force. Once the leg  64  is free of the groove  67 , its end can move across the flat surface  69 . The biasing force increases the limiting friction between the end of the leg  64  and the flat surface  69  and so enables the leg  64  to be held relatively to the hinge housing  60  in an intermediate position between grooves. In this way, intermediate locking positions are possible although in these positions the leg  64  is not as firmly locked as the locking positions provided by co-operation between the leg  64  and the grooves  67  and  68 . The end of the leg  64  completes its progression across the flat surface  69  and its end is pushed into groove  68  by the biasing force. 
     These Figures show an arrangement in which locking positions have an angular separation by 180°. The grooves can be located so that the locking positions have other angular separations. In addition, the hinge housing  60  may have more than two grooves in order to provide more than two locking positions. 
     FIGS. 7 a  and  7   b  and FIGS. 8 a  and  8   b  show details of groove profiles P 1 , P 2 , P 3 , P 4  which can be used in any of the grooves  36 ,  38 ,  67 ,  68  of different hinge embodiments shown in FIGS. 3-5, and  6   a - 6   d . The principles shown in the Figures can apply to any of the embodiments of the invention previously described. In FIGS. 7 a  and  7   b , grooves are shown which have different depths. Deeper grooves provide a greater locking force since a leg of the hinge shaft element located in the groove has to move a further distance against the biasing force in order for the hinge shaft element to be free for rotational movement. In FIGS. 8 a  and  8   b , groove profiles P 3 , P 4  are shown which have different wall angles  80  and  82 . The wall angle  80  provides a smaller locking force than the wall angle  82  since if the same force is applied to rotate a hinge shaft element in each case, in the case of profile P 3  in the FIG. 8 a  embodiment, a greater proportion of this force is available to force the leg of the grove due to the wall angle  80 . 
     FIGS. 9 a  and  9   b  show detail of hinge shaft elements  90   a  and  90   b  which can be used in different hinge embodiments. These are of the same basic configuration as the hinge shaft elements described in relation to FIGS. 3 to  5  being generally U-shaped having parallel legs  92   a  and  92   b  connected by curved portions  94   a  and  94   b . Located at the ends of the legs are oppositely extending hinge shafts  96   a  and  96   b . The legs  92   a  are longer than the legs  92   b . Since it is preferred to mount the curved portions  94   a  and  94   b  of each hinge shaft element  90   a  and  90   b  in a slot extending around a former as shown in FIG. 4, the curved portions are constrained against changing their shapes in order to allow the legs  92   a  and  92   b  to be moved towards each other. Accordingly, such movement of the legs  92   a  and  92   b  occurs by elastic deformation of the legs  92   a  and  92   b  themselves. The shorter the legs are, the greater amount of force is required to provide such movement and the higher the locking force is. 
     The locking force can also be varied by using different thicknesses of wire to form the hinge shaft element. 
     FIG. 10 shows detail of a groove used in another hinge embodiment. The groove  100  has a pair of walls  102  and  104  and a bottom  109 . Adjacent to the wall  102  is a flat surface  106 . At the junction of groove wall  102  and the flat surface  106 , a curved or rounded edge  107  is provided to reduce excessive wear or breakage. The walls  102  and  104  taper relatively to each other so that they become closer as they extend into the groove. The effect of this is to prevent a hinge shaft  108  from being able to rest at the bottom  109  of the groove  100  and instead being gripped by contact with both of the walls  102  and  104 . If there are no gaps between the hinge shaft  108  and the walls  102  and  104 , looseness between the body part and the cover part is eliminated, that is the shaft  108  cannot “jiggle” in the groove  100 . Thus, a gap is left between the hinge shaft  108  and the bottom  109 . The cooperation between the shaft and the taper angle of the walls  102  and  104  may also provide a locking force. The smaller is the taper angle, the greater is the locking force. 
     FIG. 11 shows yet another hinge embodiment. The hinge  110  comprises a hinge housing  111  and a hinge shaft element  112 . In this case the hinge shaft element  112  has legs  113  carrying hinge shafts  114  which face and extend towards each other. In FIG. 11, the legs  113  are shown located in grooves  115  and  116 . End faces of the hinge housing  111  provide flat surfaces  117  and  118  over which ends of the legs can ride. In this embodiment, when the ends of the legs  113  come out of the grooves,  115  and  116 , the legs  113  are opened so that the hinge shafts  115  are moved away from each other. 
     FIG. 12 shows still yet another hinge embodiment. The hinge  120  comprises a hinge housing  121  and a hinge shaft element  122 . The hinge housing  121  is fixed relatively to the body part and the hinge shaft element is fixed relatively to the cover part. The hinge shaft element  122  terminates in a locking loop  123  a first leg  124  of which moves in a slot  125  and a second leg  126  of which engages with a groove  127 . An end face of the hinge housing  121  provides a flat surface  128  over which the second leg  126  can ride when it comes out of the groove  127 . The hinge housing  121  comprises two half pieces  129   a  and  129   b  to allow the hinge  120  to be assembled. 
     Particular implementations and embodiments of the invention have been described. It is clear to a person skilled in the art that the invention is not restricted to details of the embodiments presented above, but that it can be implemented in other embodiments using equivalent means without deviating from the characteristics of the invention. The scope of the invention is only restricted by the attached patent claims.

Technology Classification (CPC): 6