Abstract: A mounting structure for double-bar resonators to ensure symmetrical loading of the resonator responsive to external forces. In one embodiment, the resonator is connected to a pair of mounting pads through compliant coupling members. The coupling members allow longitudinal, force-induced displacements of the mounting pads to load the resonator while making the resonator insensitive to spurious transverse displacements of the mounting pads. In another embodiment, a force is applied to a load-sensitive, double-bar resonator through a force-transmitting bar which is mounted on an elongated flexure hinge. The hinge is compliant about an axis of rotation which is perpendicular to the longitudinal axis of the resonator so that the hinge attenuates any force component acting perpendicular to the longitudinal axis of the resonator which would otherwise non-symmetrically load the resonator.

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 vibratory, force transducer includes a pair of elongate, generally parallel bars coupled together at their ends in a type of double-ended tuning fork arrangement. The bars each have a thickness of t, a width of w and a length between fixed ends of L. The distance separating the points where the bars are coupled together is m. Apparatus is provided to cause the bars to vibrate in a transverse direction and in substantially 180.degree. phase opposition. Apparatus is also provided for determining the frequency of vibration of the bars so that when the bars are subjected to either compressive or tensile forces along the longitudinal axis of the bars, the magnitude of such forces can be readily determined by simply determining the magnitude of the frequency change. The values of w and t are selected so that 0.

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.