Abstract: A force rebalance accelerometer includes a proof mass suspended by one or more flexures between stationary mounted upper and lower excitation rings. Pick-off capacitance plates formed on opposing sides of the proof mass form capacitance elements whose capacitance varies in response to displacement of the proof mass to provide a displacement signal. The displacement signal is applied to one or more electromagnets, used to force the proof mass back to a null or at-rest position. The drive current applied to the electromagnets thus represents the force or acceleration applied to the accelerometer. The electromagnets include a magnet and a pole piece which forms a magnetic return path. In order to relieve stresses due to thermal expansion, the magnet is spaced apart from the pole piece to enable the bonding area to be constrained to a minimum which, in turn, reduces the overall stress on the accelerometer.

Abstract: A force rebalance accelerometer includes a proof mass suspended by one or more flexures between stationary mounted upper and lower excitation rings. Pick-off capacitance plates formed on opposing sides of the proof mass form capacitance elements whose capacitance varies in response to displacement of the proof mass to provide a displacement signal. The displacement signal is applied to one or more electromagnets, used to force the proof mass back to a null or at-rest position. The drive current applied to the electromagnets thus represents the force or acceleration applied to the accelerometer. The electromagnets include a magnet and a pole piece which forms a magnetic return path. In order to relieve stresses due to thermal expansion, the magnet is spaced apart from the pole piece to enable the bonding area to be constrained to a minimum which, in turn, reduces the overall stress on the accelerometer.

Abstract: A force rebalance accelerometer includes a proof mass suspended by one or more flexures between stationary mounted upper and lower excitation rings. Pick-off capacitance plates formed on opposing sides of the proof mass form capacitance elements whose capacitance varies in response to displacement of the proof mass to provide a displacement signal. The displacement signal is applied to one or more electromagnets, used to force the proof mass back to a null or at-rest position. The drive current applied to the electromagnets thus represents the force or acceleration applied to the accelerometer. The electromagnets include a magnet and a pole piece which forms a magnetic return path. In order to relieve stresses due to thermal expansion, the magnet is spaced apart from the pole piece to enable the bonding area to be constrained to a minimum which, in turn, reduces the overall stress on the accelerometer.

Abstract: A force rebalance accelerometer includes a proof mass suspended by one or more flexures between stationary mounted upper and lower excitation rings. Pick-off capacitance plates formed on opposing sides of the proof mass form capacitance elements whose capacitance varies in response to displacement of the proof mass to provide a displacement signal. The displacement signal is applied to one or more electromagnets, used to force the proof mass back to a null or at-rest position. The drive current applied to the electromagnets thus represents the force or acceleration applied to the accelerometer. The electromagnets include a magnet and a pole piece which forms a magnetic return path. In order to relieve stresses due to thermal expansion, the magnet is spaced apart from the pole piece to enable the bonding area to be constrained to a minimum which, in turn, reduces the overall stress on the accelerometer.

Abstract: An accelerometer that includes a proof mass assembly comprising a paddle flexurally mounted to a support, a sensing circuit for detecting movement of the paddle, and a force rebalance system. The sensing circuit includes a capacitor plate positioned on a surface of the paddle. The proof mass assembly is clamped between upper and lower mounting pieces positioned on opposite sides of the proof mass assembly from one another. One or more fasteners extend between the upper and lower mounting pieces through the proof mass assembly. The support is shaped so as to form openings through which the fasteners pass, such that the support isolates each fastener from the paddle. This arrangement isolates the paddle from a source of contamination, provides for a more evenly distributed clamping force, and minimizes distortion of the mounting pieces. The fastener openings in the support may be shaped so as to limit movement of the paddle towards the flexures.

Abstract: An improved accelerometer of the type that comprises a paddle (30), a support (32), and suspension means (34) for suspending the paddle from the support, such that the paddle can move along a sensing axis. The support includes an unclamped portion (42) to which the suspension means is attached, and a clamped portion (40) through which the support is mounted. The invention provides restraining means (72, 100, 120, 132, 134, 176, 196, 206) separate from the clamped portion of the support, for limiting the travel of the unclamped portion in directions normal to the sensing axis, for example, along the hinge axis. The result is an accelerometer able to withstand higher cross axis shocks without failure.