GB1235318A - Apparatus for the determination of the orientation of a moving member, particularly for drilling heads - Google Patents

Abstract

1,235,318. Measuring the orientation of a drilling head. ASSOCIATION DES OUVRIERS EN INSTRUMENTS DE PRECISION. Aug.15, 1968 [Aug.17, 1967], No. 39014/68. Heading G1N. The angular orientations of the axis of a drilling head relative to the vertical and a fixed horizontal direction, e.g. North, is determined by suitable combinations of the angles α, # between the vertical and each of two shafts perpendicular to each other and to the drilling head axis, and each carrying a pendulum and an inductive transmitter determining the angles α, #. As shown, Fig.2, a drilling head incorporates a sealed cylindrical container 10, whose axis is parallel to the drilling head axis, in which are mounted two pendulums 12a, 12b. Each pendulum is supported by a shaft 13, Fig. 3, in an inner casing 14, which is itself supported on pivots 19, Fig.4, in an outer casing 22 fixed to the container 10. An unbalanced mass comprising weights 18 in circular members 17 is supported by shaft 13, and an inductive resolver having a rotor winding 25, Fig. 5, mounted on moving members 17, 18 and stator winding 27 attached to the casing 14 measures the angles α, # between the axes of the outer container 22 and the vertical. These axes are perpendicular to each other and to the axis of container 10. The signals in the stator windings 27a, 27b represent sin α and sin #, and are fed to the quadrature stator windings 34a, and 34b of a revolver 33 having perpendicular rotor windings 35a, 35b. The signal in winding 35a is automatically reduced to zero by a servomotor 37 driving the rotor assembly, and the signal in winding 35b represents the size of the angle between drilling axis and the vertical. Motor 37 also drives the rotor windings of a differential revolver 40, Fig. 6 whose stator windings are energized from a transmitter 54 associated with a magnetic compass, so that the direction of the resultant field in differential 40 determines the bearing of the drilling axis relative to the North.