Rate gyroscopes

Claim 1

A RATE GYROSCOPE COMPRISING A MAIN CASING, A GIMBAL STRUCTURE MOUNTED FOR ROTATION IN THE MAIN CASING ABOUT A FIRST AXIS, MEANS FOR EXERTING SPRING RESTRAINT ACTING AGAINST ROTATION OF THE GIMBAL STRUCTURE ABOUT SAID FIRST AXIS FROM A DATUM ORIENTATION, A GYROSCOPE MOTOR MOUNTED WITHIN THE GIMBAL STRUCTURE AND HAVING A ROTOR MOUNTED FOR ROTATION ABOUT A SECOND AXIS AT RIGHT ANGLES TO THE FIRST AXIS, A DAMPING DEVICE FOR DAMPING ROTARY MOTION OF THE GIMBAL STRUCTURE ABOUT THE FIRST AXIS, THE DAMPING DEVICE BEING DISPOSED IN A PLANE AT RIGHT ANGLES TO SAID FIRST AXIS AND SPACED APART IN ONE DIRECTION FROM SAID SECOND AXIS AND COMPRISING A FIRST MEMBER MOUNTED ON THE GIMBAL STRUCTURE AND HAVING A FIRST CYLINDRICAL SURFACE COAXIAL WITH SAID FIRST AXIS, A SECOND MEMBER MOUNTED ON THE MAIN CASING AND HAVING A SECOND CYLINDRICAL SURFACE COAXIAL WITH SAID FIRST AXIS, ONE OF THE FIRST AND SECOND CYLINDRICAL SURFACES BEING EXTERNAL AND THE OTHER INTERNAL, THE INTERNAL ONE BEING OF GREATER RADIUS THAN THE EXTERNAL ONE AND AT LEAST PARTIALLY OVERLAPPING IT AXIALLY, A BODY OF LIQUID IN THE GAP BETWEEN THE OVERLAPPING PARTS OF THE FIRST AND SECOND SURFACES, THE LIQUID BEING PROVIDED TO DAMP THE MOTION OF THE GIMBAL STRUCTURE ABOUT THE FIRST AXIS AND BEING THE ONLY BODY OF LIQUID PROVIDED FOR THAT PURPOSE, AND MEANS FOR CONFINING THE BODY OF LIQUID TO SAID GAP, SAID MEANS COMPRISING, ON EACH OF THE FIRST AND SECOND MEMBERS, A PAIR OF RINGS OF A MATERIAL WHICH IS NOT WETTED BY THE LIQUID, THE RINGS OF A PAIR EACH SURROUNDING THE FIRST AXIS AND BEING SPACED APART AXIALLY ALONG THE SURFACE OF THE MEMBER CONCERNED TO INCLUDE BETWEEN THEM AT LEAST THE OVERLAPPING PART OF THE CYLINDRICAL SURFACE AND THE FIRST AND SECOND MEMBERS BEING CONSTRUCTED OF MATERIALS HAVING DIFFERENT TEMPERATURE COEFFICIENTS OF EXPANSION, THAT OF THE MEMBER HAVING THE INTERNAL SURFACE BEING SMALLER THAN THAT OF THE MEMBER HAVING THE EXTERNAL SURFACE, THE DIFFERENCE IN SAID COEFFICIENTS BEING RELATED TO THE CHANGE OF VISCOSITY OF THE LIQUID WITH TEMPERATURE, AT LEAST PARTIALLY TO COMPENSATE FOR ANY CHANGE IN THE CHARACTERISTICS OF THE DEVICE ARISING FROM THE SAID VISCOSITY VARIATION AT LEAST WITHIN A PREDETERMINED RANGE OF TEMPERATURES, AND A BEARING WHICH IS DISPOSED IN A PLANE AT RIGHT ANGLES TO SAID FIRST AXIS AND SPACED APART IN SAID ONE DIRECTION FROM SAID SECOND AXIS, AND SURROUNDS BUT IS NORMALLY SPACED FROM A PART OF THE GIMBAL STRUCTURE SO THAT IT PERMITS ROTARY MOTION OF THE GIMBAL STRUCTURE ABOUT SAID FIRST AXIS BUT LIMITS MOTION OF THE GIMBAL STRUCTURE IN DIRECTIONS NORMAL TO THE FIRST AXIS, AND PREVENTS THE CYLINDRICAL SURFACES OF THE DAMPING DEVICE FROM COMING INTO CONTACT WITH EACH OTHER.