Position plotting apparatus for use with radar or other positional information systems

Claim 1

APPARATUS FOR TRANSFERRING POSITIONAL CO-ORDINATES OF AN OBJECT SHOWN ON A RADAR SCREEN TO A PLOTTING SHEET, COMPRISING A CASING, A PLOTTING SHEET DISPOSED IN SAID CASING, MEANS FOR CONTINUOUSLY MOVING SAID PLOTTING SHEET IN ONE DIRECTION IN ACCORDANCE WITH AN OBSERVING VESSEL''S SPEED AND DIRECTION, A CARRIAGE MOUNTED WITHIN SAID CASING FOR MOVEMENT TRANSVERSELY OF THE DIRECTION OF PLOTTING SHEET MOVEMENT, MEANS FOR MOVING SAID CARRIAGE IN ACCORDANCE WITH THE SPEED AND DIRECTION OF THE OBSERVING VESSEL, AN ARM MOUNTED ON SAID CARRIAGE FOR ROTATIONAL MOVEMENT RELATIVE THERETO, MEANS FOR ROTATING SAID ARM TO AN ANGULAR POSITION RELATIVE TO SAID CARRIAGE IN ACCORDANCE WITH THE AZIMUTH OF AN OBSERVED OBJECT, A PRINTING ELEMENT CARRIED BY SAID ARM FOR MOVEMENT LONGITUDINALLY THEREALONG, MEANS FOR MOVING SAID PRINTING ELEMENT ALONG SAID ARM IN ACCORDANCE WITH THE RANGE OF THE OBSERVED OBJECT, SAID PRINTING ELEMENT NORMALLY BEING OUT OF ENGAGEMENT WITH SAID PLOTTING PAPER, MEANS FOR SELECTIVELY PERIODICALLY URGING SAID PRINTING ELEMENT INTO CONTACT WITH SAID PLOTTING SHEET FOR MAKING A DISCRETE MARK ON THE PLOTTING SHEET TO INDICATE THE RANGE AND AZIMUTH OF A PARTICULAR OBJECT AFTER SUCH RANGE AND AZIMUTH HAVE BEEN PREDETERMINED BY RADAR, SAID SELECTIVE MEANS FOR URGING THE PRINTING ELEMENT INTO CONTACT WITH THE PLOTTING SHEET PERMITTING THE INDICATION OF A PLURALITY OF OBJECTS IN TRUE GEOGRAPHICAL RELATIONSHIP TO ONE ANOTHER, A SECOND PRINTING ELEMENT MOUNTED ON SAID CARRIAGE FOR PRINTING MARKS INDICATIVE OF THE OBSERVING VESSEL''S POSITION.