US Patent 7385873 Mass positioning adjustment mechanism for a seismic sensor

A mass position adjustment apparatus for use in a seismic sensor having axis mechanics including a pivotable boom with a defined null point is described. The apparatus comprising: (a) adjustment means for positioning the boom at the null point; (b) actuator means for moving the adjustment assembly; and (c) interface means having hard mineral members for interfacing the actuator means with the adjustment means for reducing occurrences of micro-mechanical movement when the mass position adjustment apparatus is not being operated.