Method for determining the dimensions and/or form of surfaces.

摘要

A non-contact method is provided for measuring the dimensions and form of an unknown surface by means of a transducer or sensor probe presented to the surface and determining the variations in capacity of electrical flux between said discrete capacitance electrode in the sensor and the adjacent unknown surface. To investigate the variations in the diameter and profile of a bore 33 a probe 30 having at least two angularly spaced capacitance electrodes 31 may be advanced along the axis of the bore and the capacitance values between each electrode and the adjoining surface measured. In another variant a single capacitative transducer probe may be moved over a surface to be measured. The probe may have an air supply duct discharging through one or more orifices adjacent the or each electrode to clean the unknown surface and (in the case of measurement within a bore) to provide a self-centering action.