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US 6,219,141 B1Granted
Method and apparatus for measuring waviness of paper
AssigneeAlliance Forest Products Inc.
InventorJacques Perrault
Life of this patent
Estimating the term…
Abstract
The invention provides a simple and efficient method and apparatus for carrying out a quantitative measurement of waviness in a sample of paper. This is done by stretching the paper sample to the point where all waviness is removed and measuring the elongation produced at that point. The observation of waviness and its removal is facilitated by illumination of the paper sample with low incidence light while the sample is being stretched.
Claims11
Method of measuring waviness of paper, which comprises:
- (a) stretching a sample of the paper while projecting a low incidence light on said sample;
- (b) observing said sample while it is being stretched under a low incidence light that facilitates visibility of the waviness, and stopping the stretching operation as soon as all waviness has disappeared and the paper sample becomes straight;
- and
- (c) measuring the elongation of the paper sample produced by the stretching operation.
1 more element
Apparatus for measuring waviness of paper, which comprises:
- (a) a supporting table for supporting a sample of the paper;
- (b) a holding clamp at one end of said table for clamping and holding one end of the paper sample;
- (c) a tensioning clamp at the opposite end of the table for clamping and holding the other end of the paper sample;
- (d) means for pulling the tensioning clamp to produce stretching of the paper sample;
- (e) measuring means for measuring elongation of the paper sample produced by the stretching of said sample;
- and
- (f) a source of low incidence light for projecting such light unto the paper sample during stretching of said sample to the point where waviness disappears and the paper is fully straight, said low incidence light being such as to facilitate visibility of the waviness in the sample and the point of its disappearance.
4 more elements
Dependencies are inferred from the claim text.