Abstract:
A head control comprises a control plate ( 13 ) operable by a user with his head and biasing means ( 9, 11 ) for biasing the control plate to a predetermined orientation. A joystick control ( 19 ) is operably connected to the control plate ( 13 ) such that movement of the control plate by the user is communicated to the joystick control ( 19 ).

Description:
FIELD OF THE INVENTION 
     This invention relates to a head control such as can be used by disabled persons to control a wheelchair, computer, environmental control or other appliance. 
     OBJECT OF THE INVENTION 
     It is an object of the present invention to provide a head control, such as can be used by disabled persons, which is convenient and reliable in operation. 
     SUMMARY OF THE INVENTION 
     According to the present invention there is provided a head control comprising a control plate operable by a user with his head, biasing means for biasing the control plate to a predetermined orientation, and a joystick control operably connected to the control plate such that movement of the control plate by the user is communicated to the joystick control. 
     The head control may incorporate a cover incorporating a layer of foam material for cushioning the head of the user. The foam material may comprise a substantially continuous layer. The foam material may be provided with a fabric or like external covering. 
     The control plate may be mounted in a manner such that it is pivotable by the user. The control plate is preferably pivotably mounted with a ball-and-socket type device. The pivotal mounting therefore ideally allows pivoting in all directions. 
     The control plate may incorporate a connecting member for communicating movement to the joystick control. The connecting member may be fixed to the control plate, for example substantially at right angles thereto. Alternatively, the connecting member may be hinged relative to the control plate. The connecting member may communicate movement of the control plate to the joystick control in a manner which permits a certain amount of relative motion between the connecting member and the joystick control. 
     The control plate may be mounted intermediate a pair of side plates. 
     The biasing means may comprise one or more resilient bands extending between the control plate and each of the side plates. 
     Switch means may be provided laterally of the control plate, for example two switch means may be provided to each side of the control plate, such as in each of the side plates. The switch means may be mounted in a recess in a plate member, the recess being covered by a resilient membrane in such a manner that the switch is normally spaced from the membrane. 
    
    
     For a better understanding of the present invention and to show more clearly how it may be carried into effect reference will now be made, by way of example, to the accompanying drawings in which: 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front elevational view, partly cut away, of one embodiment of a head control according to the present invention; 
     FIG. 2 is a cross-sectional view taken along the line II—II in FIG. 1; 
     FIG. 3 is a cross-sectional view of part of a side plate of the head control shown in FIGS. 1 and 2; and 
     FIG. 4 is a diagrammatic illustration of the manner in which the head control according to the present invention is operated. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENT 
     The head control shown in FIGS. 1 and 2 comprises a back plate  1  at each side of which is mounted a contoured side plate  3 . The back plate  1  facilitates mounting of the head control on a wheelchair (not shown) or the like. Each side plate comprises a forwardly extending portion  5  and a laterally inwardly extending portion  7 . The portion  7  may be inclined towards the back plate  1  to provide lateral support for a user&#39;s head. Upper and lower resilient bands  9  and  11  are secured at each end thereof to the lateral portion  7  of each side plate  3  so as to be in tension. The upper and lower resilient bands are spaced apart and a generally rectangular control plate  13  is secured to the resilient bands  9  and  11  in the upper and lower regions of the control plate  13 . Thus, the control plate is mounted intermediate the pair of side plates and the lateral portions  7  of the side plates  3  and the control plate  13  combine to form a slightly inwardly curved head rest for a user. For comfort, the side plates  3  and control plate  13  are covered with a continuous layer  15  of foam material and a fabric  16  or the like exterior covering. 
     Secured to the back plate  1  behind the control plate  13  is a supporting plate  17  on which is mounted a joystick control  19 . The supporting plate  17  extends towards, but terminates short of, the control plate  13 . An outer edge of the supporting plate  17  is provided with a pivotal connection  21 , such as a ball-and-socket type connection, which is secured to the control plate  13 . Thus, the control plate  13  is able to pivot about the pivotal connection  21 , but the upper and lower resilient bands  9  and  11  bias the control plate towards a predetermined neutral position. The control plate  13  is pivotable in all directions relative to the supporting plate thus allowing pivoting about a generally horizontal axis, about a generally vertical axis and about any axis therebetween. 
     A connecting member  23  is provided extending between the upper edge of the control plate  13  and an operating stick  25  of the joystick control  19 . The connecting member  23  extends between the control plate and the operating stick in a manner which permits a certain amount of relative motion. For example, the connecting member may be provided with an aperture through which the operating stick extends. Additionally, as an alternative to the connecting member being fixed substantially at right angles to the control plate  13 , the connecting member  23  may be mounted on the control plate  13  by way of a hinged connection. 
     As shown in FIG. 3, laterally spaced to the left and right of the control plate  13  and positioned in recesses  25  provided in each of the side plates  3  in the upper and lower regions thereof are four microswitches  27 . A resilient membrane in the form of a resilient sheet  29  covers each recess and is maintained in tension thereacross with the switch spaced from the resilient sheet. The resilient sheet  29  therefore serves to prevent the layer of foam material  15  entering a recess  25  and unintentionally operating one of the microswitches  27 . 
     The head control is operated in the manner illustrated diagrammatically in FIG.  4 . The control plate  13  is pivoted such that the lower region thereof is moved towards the back plate  1  by the user exerting pressure against the head control with the nape of his neck. The effect of such pressure is to move the lower region of the control plate towards the back plate and consequently to move the upper region of the control plate away from the back plate. Movement of the upper region of the control plate  13  away from the back plate  1  additionally moves the operating stick of the joystick away from the back plate. 
     The control plate  13  is pivoted such that the upper region thereof is moved towards the back plate  1  by the user exerting pressure against the head control with the back of his head. The effect of such pressure is to move the upper region of the control plate  13  towards the back plate  1  and thus to move the operating stick of the joystick towards the backplate. 
     The control plate  13  is pivoted such that the left hand region (as shown in FIG. 1) thereof is moved towards the back plate  1  by the user exerting pressure against the left hand side of the control plate by turning his head to the right. The effect of such pressure is to move the left hand side of the control plate  13  towards the back plate, to pivot the connecting member to the right (as shown in FIG. 1) and to move the operating stick of the joystick towards the right as shown in FIG.  1 . 
     The control plate  13  is pivoted such that the right hand region (as shown in FIG. 1) thereof is moved towards the back plate  1  by the user exerting pressure against the right hand side of the control plate by turning his head to the left. The effect of such pressure is to move the right hand side of the control plate  13  towards the back plate, to pivot the connecting member  23  to the left (as shown in FIG. 1) and to move the operating stick of the joystick towards the left as shown in FIG.  1 . 
     The control plate  13  may be pivoted in a manner which combines one of the backwards and forwards movements of the operating stick and one of the left and right movements of the operating stick by exerting pressure in one of the four corners of the control plate. Thus pressure in the upper left hand corner of the control plate  13  moves the operating stick back and to the right as shown in FIG. 1, pressure in the upper right hand corner of the control plate moves the operating stick back and to the left as shown in FIG. 1, pressure in the lower right hand corner of the control plate moves the operating stick forward and to the left as shown in FIG.  1  and pressure in the lower left hand corner of the control plate moves the operating stick forward and to the right as shown in FIG.  1 . 
     When the user releases pressure from the control plate  11  the upper and lower resilient bands  9  and  11  pivot the control plate, and therefore the operating stick of the joystick, back to a neutral position. 
     The microswitches  27  are operated in a similar manner to the corners of the control plate  13  except that the user needs to stretch his head somewhat further to the side in order to operate one of the microswitches. 
     When attached to a wheelchair, the joystick control  19  allows, for example, control of movement of the wheelchair forwards, backwards, to the left or to the right. When the user releases pressure from the headrest the operating stick of the joystick returns to the neutral position and the wheelchair comes to a halt. The microswitches  27  can be used to control different modes of operation such as slow or fast, or can switch control to the attitude of the wheelchair seat to move the seat to any desired position between a lying position and a standing position, or can be used to control other apparatus such as a computer or environmental controls.