Artillery fire control system

Claim 1

IN A FIRE CONTROL SYSTEM INCLUDING A COMMUNICATION CHANNEL FOR TRANSMITTING FIRE COMMANDS IN TRUE AZIMUTH AND ELEVATION BETWEEN A BATTERY COMMAND POST AND A GUN CREW AND MEANS FOR COMPARING THE ACTUAL GUN SETTING IN AZIMUTH AND ELEVATION WITH SAID COMMANDS, A COORDINATE CONVERTER FOR TRANSLATING APPARENT AZIMUTH AND ELEVATION DERIVED FROM THE ACTUAL MOVEMENT OF A GUN ABOUT ITS ELEVATION AND DEFLECTION AXIS INTO TRUE AZIMUTH AND ELEVATION, WHERE TRUE AZIMUTH IS TAKEN FROM AN ARBITRARY REFERENCE POINT, COMPRISING MEANS FOR TRANSLATING THE AXIS OF THE GUN IN ELEVATION TO A POSITION WHICH INTERCEPTS THE AXIS OF DEFLECTION IN AZIMUTH, A FIRST GIMBAL-LIKE MEMBER COUPLED TO THE GUN DEFLECTION MECHANISM FOR ROTATING SAID TRANSLATED ELEVATION AXIS ABOUT SAID AXIS OF DEFLECTION IN RESPONSE TO TRAINING SAID GUN IN AZIMUTH, A SECOND GIMBAL-LIKE MEMBER FOR ROTATING A THIRD AXIS ABOUT SAID TRANSLATED ELEVATION AXIS IN A PLANE PASSING THROUGH SAID AXIS OF DEFLECTION, A THIRD GIMBAL-LIKE MEMBER CONNECTED TO SAID SECOND GIMBAL-LIKE MEMBER AT SAID THIRD AXIS, SAID THIRD GIMBAL-LIKE MEMBER BEING CONSTRAINED TO ROTATE ABOUT AN AXIS IN THE SAME PLANE AS THE TRANSLATED ELEVATION AXIS, A FOURTH GIMBAL-LIKE MEMBER CONNECTEDD TO SAID THIRD GIMBAL-LIKE MEMBER TO RESTRAIN THE AXIS OF ROTATION OF SAID THIRD GIMBAL-LIKE MEMBER PERPENDICULAR TO A VERTICAL AXIS, LEVELING MEANS FOR ADJUSTING SAID VERTICAL AXIS TO TRUE VERTICAL, WHEREBY TRAINING SAID GUN IN ELEVATION AND AZIMUTH WILL CAUSE SAID THIRD AND FOURTH GIMBAL-LIKE MEMBERS TO ROTATE ABOUT THE TRUE ELEVATION AXIS AND THE TRUE AZIMUTH AXIS IN RESPONSE TO ACTUAL MOVEMENT OF THE GUN, AND ANGULAR POSITION TRANSDUCER CONNECTED TO SAID THIRD AND FOURTH GIMBAL-LIKE MEMBERS FOR PRODUCING A SIGNALS INDICATING THE TRUE ELEVATION AND AZIMUTH OF THE GUN.