Systron Donner

Richard D Marquess

A pendulous type of oil filled accelerometer is disclosed herein, specifically one which is sensitive to temperature changes sufficient to introduce a temperature related error into its output signal, if left uncorrected. A technique which compensates for these temperature changes in order to reduce the resultant error to an acceptable level is also disclosed herein. This technique uses the oil itself, specifically its sensitivity to changes in temperature resulting in changes in its density, in combination with an expandable/contractible bellows.

Accelerometer including an overall arrangement for reducing temperature

A pendulous type of accelerometer is disclosed herein and includes a sealed housing defining an oil filled internal chamber, a pendulous member located within the housing chamber and a pair of bearing mechanisms for pivotally supporting the pendulous member. The accelerometer also includes an assembly associated with each of the bearing mechanisms for preloading the latter, each of which includes two preload arrangements, a first or inner arrangement and a second or outer arrangement. The inner arrangement is provided for applying and adjusting a preload force against its associated bearing mechanism before the housing is assembled and its chamber is filled with oil and sealed and the outer arrangement is provided for further adjusting the applied preload force from outside the housing after the latter is assembled and its inner chambers filled with oil and sealed.

Bearing preload assembly for use in an oil filled accelerometer

A cylindrical bearing housing has an axial bore therethrough and external threads. A land is formed around the circumference of the bore having a width less than the axial length of the bore. A bearing member has a bearing surface on one end accessible through one end of the bore and has shoulders on each end of the bearing member. The bearing member is fabricated to pass through the bore and to have a length such that the shoulders are spaced apart a distance greater than the width of the land. An elastic filler material is disposed between the bearing member and the walls of the bore while the bearing member is suspended centrally therein, thereby retaining the bearing member axially in the bore. The bearing housing is configured for mounting and axial adjustment in a base member. A rotating member having a pair of pivots, one each on opposite sides thereof is provided having an axis of rotation passing through the pivots. When mounted bearing assemblies are positioned so that the bearing surfaces contact the pivots, a preload is set having improved stability over wide temperature variation. In one embodiment of the bearing assembly, the elastic filler material applies a shear force against the bearing member for preloading its bearing surface against the associated pivot. In another embodiment, separate apparatus, specifically a spring member applies a force against the back of the bearing member to at least aid in preloading the bearing surface against its associated pivot.

Stable preload shock mounted bearing assembly

A linear accelerometer is contained within a combination framework and case having a magnetic circuit including an annular gap with a magnetic flux density therethrough. An insulated bearing mount is fixed within the framework carrying a pair of opposed axially adjustable bearings defining a pivot axis. The bearings are supported in a resilient mass. A moving member carries a pair of pivots which seat in the bearings allowing motion of the moving member about the pivot axis. The moving member carries a torque coil disposed in the annular gap. Pick-off coils are mounted on the framework closely spaced from opposing planar conducting surfaces on the moving member. A pair of flexible leads extend between the framework and the moving member, providing electrical power to the torque coil. The flexible leads are disposed proximate to the pivot axis and at substantially 180.degree. separation thereabout to reduce static and dynamic torques on the moving member. Motion of the moving member between the pair of pick-off coils provides acceleration sensing output and a signal to the torque coil which servoes the moving member to a reference position.

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Concord, CA, United States of America

Richard D Marquess