Patent ID: 6708566
Filing Date: 2004-03-23
Classification: G01B

Abstract:
A gauge assembly for measuring a cylindrical hole in a workpiece, the gauge assembly comprising:a body portion and a cylindrical probe attached thereto and extending therefrom, the probe having a diameter sized to allow the probe to be inserted into a hole in a workpiece to be measured, the probe being provided with at least one radial port connected to a source of pressurized gas so that back pressure of the gas upstream of the port varies as a function of the local diameter of the hole in the region of the port; a bushing oriented about the probe and attached to the body portion in a manner to enable axial movement of the probe between an extended position and a retracted position, the bushing defining an abutment face to engage a region of the workpiece adjacent the hole; and a spring biasing the bushing relative to the body portion to cause the probe normally to be in the retracted position with the radial port spaced a first distance from the abutment; whereby a user may insert the probe into the hole in the workpiece to be measured and take pressure measurements at two axial positions, the first axial position corresponding to the first distance when the probe is inserted into the hole sufficiently to cause the abutment face to engage the workpiece and a second axial position when the user urges the body portion axially inward sufficiently to cause the spring to compress allowing the probe to move to an extended position placing the probe port a second distance from the abutment face.