Back to results
US 4,641,525 AGranted
Method and apparatus for checking the wall thickness of a layer
AssigneeZumbach Electronic AG
InventorHubert Merki
Life of this patent
Estimating the term…
Loading patent…
Loading patent…
AssigneeZumbach Electronic AG
InventorHubert Merki
Estimating the term…
In a method of checking the insulating sheath on a wire or cable leaving an extruder, the external diameter of the insulating sheath is continuously determined over the whole circumference by means of a first measuring apparatus and the wall thickness of the insulation is continuously detected over the whole circumference by means of a second measuring apparatus. The measured values are supplied to a computer which, inter alia, continuously determines the difference between the maximum and minimum wall thicknesses found (W.sub.max -W.sub.min). Eccentricity and minimum wall thickness of the sheath are calculated from this difference and from the measured external diameter of the insulation and the diameter of the conductor of the wire or cable, and are indicated in a display device. The measurement is thus rendered largely independent of fluctuations in sensitivity of the measuring apparatus for the wall thickness of the insulation. An apparatus for carrying out the method comprises the respective measuring apparatus and a computer for effecting the required calculations.
A method of checking the wall thickness of a layer wherein the wall thickness is measured at various points of the layer by determining the distance of a coated inner part from the accessible outer surface of the layer, to ascertain maxima and minima of the measured distance values, whereby in addition to said maxima and minima of the wall thickness, at least maxima and minima of one external dimension of a member embodying said layer, this external dimension being simultaneously measured, and data relating to at least one further quantity is derived from the difference between said maxima and minima of the wall thickness and the difference between said maxima and minima of the external dimension, for minimizing the effect of drift and non linearity upon said measured wall thickness values and said external dimension values.
A measuring apparatus for checking the wall thickness of a surface coating upon a substantially cylindrical member having a known diameter, comprising a first measuring instrument for measuring the maxima and minima of the wall thickness of the surface coating, a second measuring instrument for determining the maxima and minima of the external diameter of the surface coating, and a computer for calculating the eccentricity as a function of the difference between said measured maxima and minima of the wall thickness values and the difference between said measured maxima and minima of the external diameter values, for minimizing the effect of drift and non linearity upon said measured wall thickness values and said external diameter values.
Dependencies are inferred from the claim text.