Vehicular navigation set

Claim 1

A PORTABLE NAVIGATION DISPLAY UNIT ADAPTED FOR USE WITH PLUG-IN MEANS FOR SUPPLYING AS INPUTS TO THE UNIT CONTINUOUS ELECTRICAL ANALOGUE SIGNALS OF THE CARTESIAN COORDINATES OF CHANGE IN A VEHICLE POSITION AND A CONTINUOUS ELECTRICAL ANALOGUE SIGNAL OF THE INSTANTANEOUS VEHICLE HEADING; WHICH UNIT COMPRISES A BOX-LIKE HOUSING; SOCKET MEANS IN SAID HOUSING ADAPTED TO RECEIVE SAID PLUG-IN MEANS; A TRANSPARENT PRESENTATION SCREEN ADAPTED TO RECEIVE A CHART; A PROJECTOR MOUNTED BENEATH SAID SCREEN WITH SAID HOUSING FOR TRANSVERSE MOVEMENT ON THE HOUSING ON A LEAD SCREW, SAID LEAD SCREW BEING MOUNTED ON A CARRIAGE ADAPTED FOR LONGITUDINAL MOVEMENT IN THE UNIT ON SECOND LEAD SCREW MEANS WHICH EXTEND LONGITUDINALLY WITHIN THE UNIT ON AT LEAST ONE SIDE THEREOF AND ARE ADAPTED TO DRIVE THE CARRIAGE IN A LONGITUDINAL DIRECTION WITH THE UNIT; MEANS INCLUDING ELECTRICAL MOTORS RESPONSIVE TO THE CONTINOUS INPUT ANALOGUE SIGNALS OF THE CHANGE IN VEHICLE POSITION TO DRIVE SAID LEAD SCREWS TO POSITION SAID PROJECTOR WHEREBY IT CAN PROJECT A LIGHT IMAGE ONTO THE SCREEN TO CONTINUOUSLY DISPLAY THE INSTANTANEOUS VEHICLE GEOGRAPHICAL POSITION ON A CHART, WHEN IN PLACE ON THE SCREEN; A HEADING IMAGE ON SAID PROJECTOR, MECHANICAL MEANS FOR ROTATING SAID HEATING IMAGE; MEANS INCLUDING ELECTRICAL MOTORS TO DRIVE SAID MECHANICAL MEANS IN RESPONSE TO THE INPUT ANALOGUE OF INSTANTANEOUS VEHICLE HEADING TO ORIENT SAID IMAGE MEANS TO PROJCET A LIGHT IMAGE OF VEHICLE HEADING ON THE SCREEN; AND SWITCH MEANS ON SAID UNIT OPERABLE TO DRIVE EACH SAID MOTOR TO POSITION SAID PROJECTOR AT INITIAL DATUM POSITIONS.