Abstract: A gyroscopic device comprising a supporting structure (2; 104) and at least one mass (1; 50, 51; 100-103), the masses being attached to the structure by beams (3-6; 25-28; 52-63; 98-99). Masses, supporting structure and beams lie within a common plane when the device is at rest. A voltage source (V) to generates electromotive forces between such masses and structures to excite the masses into a vibratory primary motion. By simple flexure the beams can permit the masses to make limited motion relative to the structure in response to a rate of turn applied to the device, a measure of that rate being obtained from sensing that relative motion. By appropriate arrangement of the flexural connections (85-88) between the mass and the supporting structure, the device can measure rates of turn about two orthogonal axes. By connecting the supporting structure (104) to further structure (112) with additional flexural members (113) the device may be made capable of measuring rates of turn about three orthogonal axes.

Abstract: A method of monitoring the tension in a flexible drive belt (1) which passes around a plurality of pulleys (2, 3) includes the steps of causing a portion of the belt (1) when installed around the pulleys to vibrate at a natural frequency and detecting that frequency. In one arrangement the belt (1) is set into a vibrating motion by an impulse and the frequency of the transient vibrations measured. In another arrangement the belt (1) vibrated by a drive mechanism which receives a drive signal derived from the belt movement. Specific methods and apparatus for monitoring the tension are also applied to measuring the tension in elongate flexible members other than drive belts.

Abstract: A vibratory angular rate sensor of the kind comprising a hollow cylinder (3) secured at one end to a base (5) and free at the other end and transducers (9) on the cylinder (3) for exciting and detecting radial vibrations in the cylinder wall. The transducers (9) are positioned near the end of the cylinder (3) secured to the base (5), and the base (5) rigidly fixes the adjacent end of the cylinder (3) thereby to maximise coupling of the transducers (9) to vibrations produced in the cylinder (3) in operation of the sensor.

Abstract: A gyroscopic device comprising a resonator in the form of a disc, cylinder or like structure of circular outline, of a composition containing piezo-electric material and preferably made of a an integral mass of such material. The resonator is excited into dilatation-type vibration by electric currents applied to exciting electrodes electro-deposited in a regular pattern around the circumference of the structure, and these vibrations are sensed by detecting electrodes similarly deposited around the wall in a similar but angularly displaced pattern. A measure of any rate of turn which the structure is undergoing about its axis can be derived from the resulting phase shift of the electrical output from the detecting electrodes.

Abstract: A gyroscopic device comprising a beam, column or other continuous unitary structure of consistent vibratory characteristics along its full length and including piezoelectric material. The piezoelectric effect is used both excite the structure into resonant vibrations along a first axis and then, when a rate of turn is applied along a second axis at right angles to the first, to detect that rate of turn by sensing vibrations set up in the beam in a direction parallel to a third, orthogonal axis due to Coriolis forces resulting from the applied rate of turn. The beam may be held at both ends, or may be supported at one end only with the other end free. The vibrations applied to and sensed within the beam by means of the piezoelectric effect may be parallel, transverse and radial relative to the beam axis, or may be in a rotary sense around that axis. A mode of vibration in which opposite faces of the beam oscillate in parallel directions but out-of-phase is also disclosed.

Abstract: A gyroscope in which sprung elements are supported in cantilever fashion from a rotor and extend in a generally inward direction towards the rotor axis. The centers of mass of the elements are out of alignment with the rotor axis and the elements are free to vibrate in directions parallel to that axis. The output of the gyroscope is derived from detection of these vibrations.