Abstract:
A collapsible keyboard that is collapsible between a deployed configuration in which the keyboard is generally planar and a collapsed configuration, the keyboard being foldable about three substantially parallel axes between the deployed and collapsed configurations, the keyboard having four rigid subframes for supporting keys, each subframe being pivotally connected at a folding axis to an adjacent subframe. The keyboard preferably has support frames supporting keys thereon. The keys are slidable and are connected by flexible connectors that span the axes. The keyboard can be locked in either the collapsed or deployed configuration and can be combined with a remote communication unit.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a continuation of International Application PCT/GB98/00841, with an international filing date of Mar. 20, 1998, which claims priority from GB/9705881.2 and has a priority date of Mar. 21, 1997. 
    
    
     The present invention relates to a collapsible keyboard. 
     There have been various proposals for collapsible keyboards for use with computers and particularly for use with portable computers. One of the main constraints when attempting to reduce the size of a portable computer is the fact that the keyboard must be greater than a certain minimum size in order to be usable by a person. If a keyboard is too small, the keys become too small and cramped to be used effectively. In several prior art proposals, including for example that shown in U.S. Pat. No. 3,940,758, the number pad of the keyboard is positioned on a separate part of the keyboard which is attached to the main portion of the keyboard holding the alphabetic and other control keys so that the number pad can be folded over onto the main part of the keyboard when the keyboard is not in use, thereby to reduce the overall size of the keyboard. However, in practice, this still does not reduce the overall size of the keyboard very much. As the other components of portable computers, such as display screens and hard disk drives, become increasingly smaller as the technology improves, there is an increasing need to reduce the overall size of the keyboard. Furthermore, there are various computers available now or shortly which do away with a keyboard and use a pen input to a touch-sensitive screen or voice-activation for example. However, users often find a keyboard convenient to use, but do not wish to carry a separate keyboard with them as keyboards have conventionally been very bulky. There is therefore also a need for an independent keyboard which can be used as an optional accessory to a computer and which is conveniently stored when not in use. Such a keyboard could also be used with mobile telephones, electronic organisers and potentially with interactive television systems, screen telephone units, and the like. 
     EP-A-0640489 discloses a foldable computer which has a keyboard which can be folded in half about a central axis transversely of the keyboard and which is attached to a separate portion containing the processor which is foldable about an axis arranged longitudinally of the keyboard. 
     U.S. Pat. No. 5,459,461 discloses an inflatable keyboard which can be deflated and then rolled or folded for storage and inflated for use. 
     SUMMARY OF THE INVENTION 
     According to the present invention, there is provided a collapsible keyboard, the keyboard being collapsible between a deployed configuration in which the keyboard is generally planar and a collapsed configuration, the keyboard being foldable about three substantially parallel axes between the deployed and collapsed configurations, the keyboard having four rigid subframes for supporting keys, each subframe being connected at a folding axis to an adjacent subframe. 
     Preferably, the keyboard is foldable in one direction about the middle axis and in the opposite direction about the adjacent axes. Thus, the keyboard may fold through a “W” shape so as to collapse in a concertina-like fashion. 
     The keyboard may have keys at least some of which are slidable in the plane of the keyboard in a direction transverse of said axes. As the keyboard is folded, the slidable keys, which in the deployed configuration may overlap a folding axis, can move away from said folding axis so as to facilitate or allow folding of the keyboard and also to provide a straight edge with no keys overlapping the folding axes in the collapsed configuration. 
     At least some of the slidable keys may be connected to other keys by flexible means passing over an axis so as to cause said at least some slidable keys to slide as the keyboard is folded. The keyboard is constructed such that at least some of the slidable keys are biased toward their deployed position when the keyboard is deployed. 
     The keyboard may further comprise a support structure for keys. The support structure is preferably a matrix of cells, each cell accommodating a respective key. In the collapsed configuration, the support structure preferably encases each depressed key. This protects and hides the key mechanism, particularly at the edges of the folding axes in the collapsed configuration. Where some of the keys are slidable, corresponding portions of the support structure may be slidable with the slidable keys. 
     A lock may be provided for locking the keyboard in its deployed configuration. The lock may comprise locking elements that are biased into recesses in subframes of the keyboard. The lock may be releasable by operation of a button connected to the locking means. 
     A lock may also be provided for locking the keyboard in its collapsed configuration. 
     The keyboard may be combined with a remote control unit. This has particular application for use with a television type unit, for example. 
     While reference is made herein primarily to the keyboard being useful for a portable computer, it will be appreciated that the principles of the present invention can be applied to a keyboard for a desktop computer, a so-called “personal digital assistant” or “electronic organiser”, or used as an independent portable pocket-sized keyboard for use with such devices, or, indeed, to any kind of generally planar input device such as a keyboard for a musical instrument such as an electric piano or synthesizer. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Embodiments of the present invention will now be described by way of example with reference to the accompanying drawings, in which: 
     FIGS. 1A to  1 C are respectively a plan view, a side elevation and an end elevation of an example of a keyboard in its deployed configuration; 
     FIG. 2 is a schematic fragmentary plan view of the keyboard; 
     FIGS. 3A to  3 C are respectively views of the keyboard just after folding has begun, almost in its collapsed configuration, and in its fully collapsed configuration; 
     FIG. 4 is an exploded view of one section of the keyboard; 
     FIGS. 5A to  5 C are sequential perspective views of a preferred assembly method for a portion of the keyboard; 
     FIG. 5D is a partial exploded view of an alternative embodiment of FIG. 5A; 
     FIG. 6A is a partial schematic plan view of a preferred locking mechanism for the present keyboard; 
     FIG. 6B is a side view of a first feature of the mechanism of FIG. 6A; 
     FIGS. 6C and 6D are a partial plan view and a partial perspective view, respectively, of a second feature of the mechanism of FIG. 6A; 
     FIGS. 7A and 7B are a partial schematic plan view and a partial schematic perspective view, respectively, of an alternative locking mechanism for the keyboard; 
     FIG. 8 is a disassembled plan view of bases of the subframes; 
     FIG. 9 is a cross-sectional view of a further example of a keyboard in accordance with the present invention; 
     FIG. 10 is an expanded view of a portion of FIG. 9; and 
     FIG. 11 is a diagrammatic perspective view of a further example of a keyboard in accordance with the present invention in its collapsed configuration with the addition of keys on the front panel. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A keyboard  1  is particularly useful for providing a compact keyboard for a portable computer. The keyboard  1  is generally planar in the deployed configuration shown in FIG.  1 . The keyboard  1  has plural keys  2  distributed over its upper surface generally in a format which is familiar to users of computer keyboards in general. In particular, there is a row  3  including function keys; a row  4  including digits (from 1 to 9 and 0); three rows  5  which include alphabetic keys; and a space bar  6  which, for reasons to be described below, is in two parts  6 A, 6 B. Other keys such as “CTRL”, “ALT”, “TAB”, etc. which are familiar to computer keyboard users are also provided generally in their conventional positions. 
     The keyboard  1  has a support frame  10  which is in four generally rectangular portions referred to herein as subframes  11 - 14 . The subframes  11 - 14  are connected in series at respective long edges to each other by hinges  15  as shown. In particular, the first subframe  11  is connected to the subframe  12  by hinges  15  at their adjacent corners, these hinges  15  being mounted on or towards the uppermost portion of the keyboard  1 . The third and fourth subframes  13 , 14  are similarly connected at adjacent comers by hinges  15  on the uppermost surface of the keyboard  1 . The second and third subframes  12 , 13  are connected at their adjacent corners by hinges  15  which are fixed on or towards the lowermost surface of the keyboard  1 . Thus, as shown in FIGS. 3A and 3B for example, the keyboard  1  folds in a concertina-like fashion through a W-shape in which the central axis  16  moves relatively upwards whilst the two outermost axes  17  move relatively downwards. The arrangement of the keys  2  and the hinges  15  is preferably such as to allow the keyboard  1  to be completely collapsed to the configuration shown in FIG. 3C in which the various keys  2  on the subframes  11 - 14  touch one another and depress such that the keys are stored under compression in the collapsed configuration. This provides for an extremely compact collapsed keyboard  1 . For example, in the deployed configuration shown in FIG. 1, the keyboard may have a size of 30×15×0.5 cm with the keys protruding 3 mm above this when not depressed, whereas, in the collapsed configuration, the collapsed keyboard  1  may have a size of just 8×15×2 cm. 
     As the keyboard  1  is folded towards its collapsed configuration, the keys immediately either side of the outermost folding axes  17  will tend to approach each other and, indeed, may obstruct the folding of the keyboard  1 . The keys may also overlap the outermost folding axes  17  in the collapsed configuration, which may make the keys vulnerable to damage and also may produce an unsightly jagged edge in the collapsed configuration. 
     There are various possible ways of preventing these keys from hindering complete collapse of the keyboard  1 . For example, computer keys are often bevelled so that their base is wider than their top. This bevelling alone may be sufficient to prevent the keys adjacent the outermost axes  17  from contacting each other. Alternatively or additionally, a dead space or recess may be formed under the keys adjacent the outermost axes  17 , these recesses accommodating the edges of these keys as the keyboard  1  is folded. The recesses may be covered by a flexible flap which is moved aside by the keys when the keyboard  1  is folded to its collapsed configuration. The recesses will be described further below. 
     However, in the most preferred embodiment, the keys which otherwise might cause obstruction are allowed to be slidable so that as the keyboard  1  is folded, the slidable keys can move away from the axes  17  to allow complete collapse of the keyboard  1  to take place. The use of sliding keys means that the keyboard  1  can retain the familiar relatively staggered layout of the keys in the deployed configuration, which is particularly important for touch typists who rely on the various keys  2  being in predetermined positions on a keyboard  1 . Furthermore, the use of sliding keys allows those keys to be withdrawn into the folded keyboard  1 , which provides a straight edge at the outermost folding axes  17  and also allows the keys to be protected in the collapsed keyboard  1 . 
     The keys which are made slidable are preferably those that overlap or project over the outermost axes  17 . For convenience, the slidable keys may be grouped in sets which respectively extend across the width of the subframe  11 - 14  concerned. In particular, the first four digit keys  40  mounted on the first subframe  11  are slidable away from the first foldable axis  17  (i.e. to the left in FIGS. 1A and 3A) and can move into a recess  18  provided in edge of the subframe  11 . Similarly, the last three digit keys  41  which are mounted on the fourth subframe  14  to the right hand side of the keyboard  1  can move into a recess  19  provided in the edge of the subframe  14 , the last set  41  of the digit keys  4  moving away from the centre of the keyboard  1  and the rightmost folding axis  17 . In the first row of alphabetic keys  5  which is immediately below the digit keys  4 , the two sets  20 , 21  of central keys, i.e. those mounted on the two central subframes  12 , 13 , can move towards each other, i.e. towards the central axis  16  and away from the outermost axes  17 , so that these sets of keys  20 , 21  clear the outermost axes  17  during folding of the keyboard  1 . Other sets of keys supported on the central subframes  12 , 13  and which also overlap the outermost axes  17  can be arranged to slide towards the central axis  16  as indicated in FIG. 3A, again to ensure that these sets of keys do not obstruct folding of the keyboard  1 , such as sets  22 , 23 . The last two rows of keys including the part  6 A of the space bar  6  on the second subframe  12  are movable as a set  23 . Finally, if any of the keys overlap the central axis  16  by a significant degree, for example the set  42  of digit keys supported by the third subframe  13 , such keys can be arranged to slide slightly away from the central axis  16  so that such keys  42  do not project beyond the edges of the respective subframes  11 - 14  when the keyboard  1  is in its collapsed configuration. It will be appreciated that the space bar  6  needs to be split into two portions  6 A, 6 B as mentioned above as the space bar  6  crosses the central axis  16  and, as a consequence, will have two linked electrical connection contact points. 
     In FIG. 4, there is shown an exploded view of a typical subframe  11 . It will be understood that the other subframes  12 - 14  are constructed in a similar fashion. The subframe  11  has a planar rectangular base  50  made of a rigid material such as metal or rigid plastics. A planar circuit board  52  is fixed to the base  50  and is connected to circuit boards on the other subframes  12 , 13 , 14  by a flexible wire loop (not shown). A rubber bubble sheet  54  fits over the circuit board  52  to provide electrical connection to the circuit board  52  when a key  2  is pressed. The rubber bubble sheet  54  acts in a known manner and provides a spring bias to the keys  2 . A support structure  56  for the keys  2  fits over the bubble sheet  54  and is preferably fixed to the bubble sheet  54 , for example by gluing. The support structure  56  may be plastics and is divided into individual cells  57  each of which supports a respective key  2 . The keys  2  are retained in their respective cells  57  by a scissor-action spring  58  fixed to the key  2  and respective cell  57 . The scissor-spring  58  acts in a known manner to secure and control the movement of the key  2 . An upper edge trim  60  fits over the support structure  56  to provide rigidity and can be fixed to the base  50  by any suitable means, such as by screws or clips (not shown). The hinges  15  are fitted to the edge trim  60 . 
     In a preferred embodiment, base  50  has recesses  51 , the circuit board  52  has recesses  53 , and the bubble layer  54  has recesses  55 , all of which allow keys on an adjacent subframe to move into the recesses  51 , 53 , 55  as necessary during folding as mentioned above. FIG. 8 shows the position of the recesses  51  in the bases  50  of each of the subframes  11 - 14 , the various recesses  51  being positioned according to the positions of the sliding keys mounted on the particular subframe  11 - 14 . It will be appreciated that recesses are not required adjacent the central folding axis  16  for example because the central subframes  12 , 13  fold outwards. 
     In order to allow keys  40  to be slidable as mentioned above, the sections  54 ′, 56 ′ of the bubble layer  54  and support structure  56  that correspond to the sliding keys  40  are preferably made as separate components, as indicated in FIG. 4 for example. As shown in FIGS. 5A to  5 C, the sliding portions  54 ′, 56 ′ of the bubble layer  54  and support structure  56  have small rectangular slots  61  through which screws  62  pass for fixing the sliding portions  54 ′, 56 ′ to the base  50 . Because the fixing screws  62  pass through rectangular slots  61 , the sliding portions  54 ′, 56 ′ of the bubble layer  54  and support structure  56  can move during folding as necessary and therefore carry the sliding keys  40  with them. A similar construction is used for all of the sliding keys mentioned above. Optionally, as shown in FIG. 5D, the screws  62  may be slightly longer and pass through a small spring  63  before passing through the bubble layer  54  and support structure  56  to provide some freedom of movement in the vertical direction during folding of the keyboard  1 . 
     A system of springs and flexible straps or links are preferably provided in order to encourage or ensure that the sliding keys move as required during folding and unfolding of the keyboard  1 . In particular, those keys  20 , 21 , 6 A that move towards the central folding axis  16  are connected to the adjacent keys towards which they move by flexible straps or links  70  which pass over the central folding axis  16  so that, as the keyboard  1  is folded, the sliding keys are pulled towards the central axis  16 . Return springs  71  connect the other ends of these sliding keys to fixed keys mounted on the outermost subframes  11 , 14  to ensure that these sliding keys return to the proper position when the keyboard  1  is unfolded to its deployed configuration. Optionally, the return springs  71  may be placed within the support structure  56  and connected laterally to the screws  62 . 
     The first set  40  of digit keys is preferably connected by a further spring  72  to the wall of the recess  18  in the first subframe  11 , the spring  72  biasing the first set  40  of digit keys into the recess  18  when the keyboard  1  is folded. A resilient link  70  connects the other end of the first set  40  of digit keys to the adjacent fixed digit keys  43  mounted on the second subframe  12 , which ensures that the first set  40  of digit keys are pulled back to their proper position when the keyboard  1  is unfolded. A similar spring  73  connects the last set  41  of digit keys mounted on the fourth subframe  14  to the recess  19  in order to bias this last set  41  of digit keys into the recess  19  during folding. The last set of digit keys  41  is connected by a flexible link  74  to the set of digit keys  42  mounted on the third subframe  13  in order to carry the third set  42  of digit keys away from the central folding axis during folding. A further spring  75  connects the other end of the third set  42  of digit keys to the fixed digit keys  43  on the second subframe  12  so that the third set  42  and last set  41  of digit keys are pulled back to their proper position when the keyboard  1  is deployed. 
     A mechanism for locking the keyboard  1  in its deployed configuration is shown in FIGS. 6A to  6 D. Three sprung bolts  80 , 81 , 82  slide in recesses  83  provided in the edge trims  60  and/or bases  50  of the subframes  11 - 14 . The bolts  80 , 81 , 82  are preferably connected in series to each other by wires  84 . The wire  84  running through the first subframe  11  is connected to a tab  85  which projects through an opening  86  in the edge trim  60  of the first subframe  11 . The user simply pulls the tab  85  to the left as shown in the drawings, which causes the respective bolts  80 , 81 , 82  to move to the left in the drawings, thereby allowing the keyboard  1  to be folded. The position of the tab  85  in the top left hand corner of the keyboard  1  means that it will be locked in position by the second subframe  12  in the collapsed configuration of the keyboard  1 . Springs  87  bias the bolts  80 , 81 , 82  in the locking direction. 
     An alternative locking mechanism may have plural rigid rods or bars in place of the wires  84  of the example shown in FIGS. 6A to  6 D. The rods are interconnected in series by flexible hinges such as of rubber and an end one of the rods is connected to the operating tab  85 . The use of rigid rods does away with the need for the springs  87  of the example shown in FIGS. 6A to  6 D. The rods may further be connected to the various sets of sliding keys so that the keys are slid into position and the keyboard  1  is locked open by movement of the tab  85  in a first direction. The tab  85  is operated in the reverse direction to withdraw the locking rods and to slide back the sliding keys to allow the keyboard  1  to be collapsed. 
     A yet further alternative locking mechanism is shown in FIGS. 7A and 7B. Instead of the linear bolts  80 , 81 , 82  of the example shown in FIGS. 6A to  6 D, sector-shaped locking bars  90 , 91 , 92  can pivot in sector-shaped recesses  93  provided in the subframes  11 - 14 . The locking bars  90 , 91 , 92  are connected to one another by wires  94  which are again connected to a tab  85  which projects from the surface of the first subframe  11 . When the tab  85  is pulled to the left, the respective locking elements  90 , 91 , 92  are all caused to pivot out of locking engagement with the adjacent subframe  12 , 13 , 14 , thereby allowing the keyboard  1  to be folded. The locking elements  90 , 91 , 92  are biased by springs  95  into engagement with the adjacent subframe  12 , 13 , 14  so that the keyboard  1  is locked when in its deployed configuration. 
     The very outermost edges of the first and fourth subframes  11 , 14  are preferably provided with upward facing curves  100 , 101  which allows the keyboard  1  to have a smooth and attractive finish when in its collapsed or folded configuration. A clip  102  may be provided on one of the upward curves  100  so as to engage in a corresponding recess  102  on the other upward curve  101  in order to lock the keyboard  1  in its collapsed configuration. A similar clip may act at the base of the second and third subframes  12 , 13  to prevent the central portion of the keyboard  1  from opening out when the keyboard  1  is in its collapsed configuration; such a clip may be provided by a thin magnetic strip attached to the base  50  of the second and third subframes  12 , 13 . The curves  100 , 101  also serve to protect any keys which overhang the central folding axis  16 . This is facilitated by virtue of the first and fourth subframes  11 , 14  being wider than the second and third subframes  12 , 13 . It will be understood that various other locking mechanisms may be suitable for performing the desired locking function and are within the scope of the present invention. 
     The relative height of the keys  2  can be such that the keys  2  touch each other on their top surfaces when the keyboard  1  is in its folded configuration, the keys  2  depressing each other so as to reduce the thickness of the folded keyboard  1  to an absolute minimum. 
     There is space within the subframes  11 - 14  to accommodate a short piece of cable and connector for connecting the keyboard  1  to a device such as a computer. Alternatively or additionally, a small infra-red unit may be contained within the subframes  11 - 14  for providing a connection to a suitably equipped computer. As a further alternative, a connection cable could be accommodated within the space under the curved sections  100 , 101 . Such a cable may have a slightly magnetic outer sheath so that it can be stored tidily when the keyboard  1  is in its collapsed configuration. 
     An alternative mounting for the keys  2  is shown in FIGS. 9 and 10. The base  50  of each subframe  11 - 14  is provided with plural parallel rails  110  of T-shape cross-section across its centre. Each rail  110  therefore provides opposed flanges  111  raised from the surface of the base  50 . Corresponding side flanges  112  are provided at the edges of the base  50  as shown. The support structure  56 , particularly the sliding support structure  56 ′, to which the keys  2  are fixed is provided in each case with a corresponding pair of opposed flanges  113  which engage under the flanges  111 , 112  of the base  50  to retain the support structure  56 , 56 ′ on the base  50 . This is a particularly advantageous method of mounting for the sliding keys as manufacture of the keyboard  1  is simplified. 
     A further example of the present invention is shown in FIG.  11 . The folding keyboard  1  is combined with a remote control unit having control keys  120  on an upper surface (i.e. the rear of one of the end subframes  11 ) of the keyboard  1  when in its folded configuration. Thus, when the keyboard  1  is in its folded configuration, it can be used as a remote control device for controlling any suitable apparatus. The keyboard  1  can be deployed for use as a keyboard whenever required, and can even be used to send signals corresponding to data input via the keyboard  1  to the apparatus being controlled remotely. Examples of such include televisions, interactive television systems, screen telephones, computers connected to the Internet, so-called “network computers” (which have only a small storage capacity hard disk or no hard disk at all), etc. This combination of a remote control unit and a folding keyboard  1  according to the present invention conveniently provides the user with full keyboard functions whilst allowing the remote control unit to remain small and unobtrusive when keyboard functions are not required. This may be particularly advantageous in a domestic environment. 
     In a preferred embodiment keyboard  1  includes is constructed such that at least some of the keys, and preferably at least some of the slidable keys, are biased toward their deployed position when the keyboard is deployed. Keys  2  can be biased by any suitable type of spring or the like. It is further preferred that keyboard  1  be constructed such that when it is in its collapsed configuration, the support structure encases each depressed key. This helps prevent damage to the keys during transport of the keyboard. 
     While an embodiment of the present invention has been described with particular reference to the examples illustrated, it will be appreciated that variations and modifications may be made to the examples described within the scope of the present invention. For example, the keys  2  may be of the touch pad/membrane type instead of the mechanically sprung type shown in the drawings. This may allow the keyboard  1  to have a slimmer cross-section in its collapsed configuration and may also save in manufacturing costs compared to the mechanically sprung keys  2  described above. It may also avoid the need to have some of the keys slide during deployment and collapsing of the keyboard  1 , which would certainly provide savings in manufacturing costs. A particularly slim collapsed keyboard  1  is very desirable when the keyboard  1  is combined with a remote control unit as described above, or with portable devices such as mobile telephones.