Accelerometer

Claim 1

An accelerometer comprising a casing having a sensing axis, a pendulum mounted in said casing coaxially therewith, said pendulum being adapted to move with respect to said casing in response to accelerations along said axis, first and second capacitive pickoff units mounted on said pendulum coaxially therewith to generate a signal in proportion to said movement, first and second torquer units disposed adjacent said respective pickoff units coaxially therewith for establishing first and second variable forces on said pendulum, said forces varying substantially in direct proportion to the magntidue of said signal, said forces providing a net force-to-movement ratio having a selective scale factor, first and second manual torque adjusting units for adjusting said torquer scale factor before start-up, first and second automatic temperature responsive torque adjusting units for automatically adjusting said torquer scale factor after start-up, and bias means to adjust the alignment and null position of said pendulum before start-up, wherein said casing has first and second axially spaced end walls and a cylindrically shaped peripheral wall forming a cylindrically shaped sealed cavity containing a fluid and symmetrically disposed about said sensing axis, and wherein said pendulum has a flat circular web plate portion and has a cylindrically shaped outer flange ring portion symmetrically disposed about said sensing axis, wherein said first and second capacitive pickoff units respectively include first and second capacitor plates respectively mounted on axially opposite faces of said pendulum web plate portion, wherein said first and second capacitive pickoff units have means to establish an electricaL circuit including said capacitor plates, wherein said end walls respectively have substantially flat axially inner faces, said flat inner wall faces being substantially parallel and being separated by a space of substantially uniform thickness, and wherein said first and second capacitor plates respectively have substantially flat axially outer faces respectively facing said flat inner wall faces, said flat outer plate faces being substantially parallel to and being separated from said flat inner wall faces respectively forming first and second gaps having selective thicknesses whereby the ratio of gap thickness to plate area is minimized.