Resonator force transducer

A vibratory, double-bar force transducer comprising a generally rectangular sheet of material having a thickness t, a width 2 w+g, and a length L, said sheet of material including an elongate slot having a length m and centrally located therein to divide the sheet into two bar segments, each having a width w, said slot having a width g, wherein

• 0.4<t/w<4, and
• L/m.gtoreq.1, and
• means for causing said bar segments to vibrate at a frequency f in substantially 180.degree. phase opposition in a transverse direction, and
• means for determining the frequency of vibration of said bar segments.

A vibratory force transducer comprising

• an elongate beam having a thickness t and width w, wherein
• 0.4<t/w<4,
• means for causing said beam to resonate at a frequency f in a transverse direction, and
• wherein t and w are selected so that for any value of S in the range S.sub.min to S.sub.max, where S is the force sensitivity of the transducer, with positive values of S representing tensile forces and negative values representing compressive forces, and S.sub.min and S.sub.max are the minimum and maximum values of S respectively used to define the desired operating range, at one of the following inequalities holds:
• ##EQU26## where f.sub.p1 is the fundamental resonant frequency of the beam in a spurious mode where the beam oscillates in a direction normal to the transverse plane, f.sub.p2 is the second overtone of f.sub.p1, and f.sub.p3 is the third overtone of f.sub.p1.

A vibratory force transducer comprising

• at least one elongate beam having a thickness t and a width w,
• means for causing said beam to resonate at a frequency f in a transverse direction,
• wherein t and w are selected so that for any value of S in the range S.sub.min to S.sub.max, where S is the force sensitivity of the transducer, with positive values of S representing tensile forces and negative values representing compressive forces, and S.sub.min and S.sub.max are the minimum and maximum values of S respectively used to define the desired operating range, at least one of the following inequalities holds:
• ##EQU27## where f.sub.p1 is the fundamental resonant frequency of the beam in a spurious mode where the beam oscillates in a direction normal to the transverse plane, f.sub.p2 is the second overtone of f.sub.p1, and f.sub.p3 is the third overtone of f.sub.p1.

A vibratory force transducer comprising

• a pair of elongate, generally parallel bars coupled together at their ends and adapted to vibrate 180.degree. out of phase in a transverse direction, said bars having a thickness t and a width w, the distance between locations at which the bar ends are coupled together being m and the lengths of the bars being generally L,
• means for causing said bars to resonate at a frequency f in substantially 180.degree. phase opposition in a transverse direction,
• wherein t, w, L, and m are selected so that for any value of S in the range S.sub.min and S.sub.max, where S is the force sensitivity of the transducer, with positive values of S representing tensile forces and negative values representing compressive forces, and S.sub.min and S.sub.max are the minimum and maximum values of S respectively used to define the desired operating range, at least one of the following inequalities holds:
• ##EQU28## where f.sub.p1 is the fundamental resonant frequency of the bars in a spurious mode where the bars oscillate in phase in a direction normal to the plane of the bars, f.sub.p2 is the second overtone of f.sub.p1, f.sub.p3 is the third overtone of f.sub.p1, and f.sub.d is the fundamental resonant frequency of the bars in a spurious mode where the bars oscillate out of phase in a direction normal to the plane of the bars.