Abstract: A digital angular rate and acceleration sensor is constructed with force-sensitive resonators positioned longitudinally on one or both sides of the neutral bending plane of a cantilevered structure. The cantilevered structure has an inertial proof mass at its free end with a periodic velocity applied sideways to the bending plane. Rotation about the longitudinal axis, which produces periodic Coriolis acceleration, as well as inertial acceleration applied perpendicular to the bending plane, generate tensile and compressive forces on the resonators thereby altering the resonant frequencies that are thus a measure of angular rate of rotation and acceleration.

Abstract: Digital pressure transducers employing force-sensitive resonators are designed according to a method that eliminates spurious mode resonances. The dimensional and geometrical relationships of the force-producing pressure elements and structures are chosen such that spurious modes of oscillation are not excited by the resonant modes of the force-sensitive resonators.

Abstract: A load cell having single or multiple resonators arranged to receive a strain that is proportional to the strain in a beam to which the resonator(s) is attached. Arrangement of the multiple resonators with respect to a force-bearing beam of the cell determines whether the cell is a bending mode load cell or a shear mode load cell. Absolute and differential pressure sensors, accelerometers and weighing devices are disclosed which employ the multiple-resonators of the invention.

Abstract: A digital differential pressure sensor with relatively low sensitivity to common mode line pressure errors. The sensor includes an airtight enclosure having a pair of pressure ports through which pressures are coupled to opposite sides of a pressure-sensing diaphragm, bellows, or Bourdon tube. The pressure-sensing elements generate torques which are transmitted by a shaft to stress-sensitive resonators which are isolated from the torque-producing elements by a sealed, flexible tube.

Abstract: A digital pressure transducer is formed by mounting a force-sensitive resonator to a structure of nonsymmetrical configuration which produces loads under applied pressure. The frequency of the resonator is measured to provide a digital indication of the applied pressure.

Abstract: A mounting structure for crystal resonators used as frequency standards and transducers which maximizes performance and reduces the sensitivity to environmental errors. In one embodiment, force sensitive crystal resonators having inherent unmounted temperature sensitivities are used in conjunction with reactive spring-like mounting arrangements having predetermined temperature stress characteristics such that the thermally induced mechanical stress of the mounting arrangements changes, compensates, and optimizes the overall combined temperature characteristics. In another embodiment crystal resonators are isolated from the external environment so that they are capable of sensing forces while operating in a vacuum or inert atmosphere. Environmental isolation is provided by bellows and/or diaphragm arrangements used alone or in conjunction with air-tight enclosures which enable forces to be applied to stress-sensitive crystals while isolating the crystals from the external force producing environment.

Abstract: A digital differential pressure transducer with relatively low sensitivity to common mode line pressure errors. The transducer includes an airtight enclosure having a pair of pressure ports through which pressure is coupled to opposite sides of a pressure-sensing diaphragm or bellows. The force generated by the pressure differential across the diaphragm or bellows is coupled to a stress-sensitive resonator either directly or through a force-transmitting structure. A first bellows extends from the diaphragm or a bellows end cap. The first bellows has an effective area which is substantially smaller than the effective area of the pressure-sensing diaphragm or bellows so that it applies substantially less pressure-induced stress to the resonator than does the pressure-sensing diaphragm or bellows. A second bellows has an effective area and a mounting position chosen to counteract the effect of the first bellows on the pressure-sensing diaphragm or bellows.

Abstract: A system for isolating the mounting pads of a vibrating beam or tuning fork force transducers from longitudinal vibrations generated by transverse vibrations of the beam or tuning fork tines which extend between the mounting pads. The system includes an arrangement of longitudinally resilient support links and masses that flex responsive to change in the length of the beam or tines as the beam or tines vibrate transversely. The support links and masses thus isolate the mounting pads from the longitudinally vibrations of the beam or tuning fork tines while allowing transmission of forces applied between the mounting pads which vary the force dependent resonant frequency of the beam or tuning fork.