US 6,662,072 B2Granted

Grinding process and control device for a knife shaft

AssigneeEastman Kodak Company

InventorsOlivier L. Berne, Frederic J. Gaudiller

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Abstract

The present invention relates to a process and control device to grind a knife shaft used in a machine intended for cutting sheets of materials into strips, for example, sheets of paper, plastic, plates of photosensitive film or any other material having the form of thin sheets. The process includes determining the actual differences of position of the knives of the knife shaft in relation to a theoretical position and then dividing these differences to cut the film strips by widths practically equal to one another, and determining the quantities of material to be eliminated by grinding for each knife. This process especially finds its principal application in the photographic industry, in particular on grinding machines for the knives of knife shafts equipping the film slitters.

A grinding process for knives placed on a periphery of a knife shaft, the process comprising the steps of:

(a) defining a difference of an actual position of each of the knives in relation to a reference position corresponding to a theoretical position of said knives, by determining an algebraic value of a difference between an actual pitch measured between two consecutive knives and a theoretical pitch for each different pair of consecutive knives of the knife shaft;
(b) calculating an average algebraic value of the algebraic values of the differences between the actual pitch and the theoretical pitch determined at said step (a), by dividing a sum of said algebraic values of the differences by a total number of different pairs of consecutive knives of the knife shaft;
(c) determining an algebraic value corresponding to a first corrected relative position of each of the knives, by removing said average algebraic value of the differences calculated at said step (b) from each of the algebraic values of the difference between the actual pitch and the theoretical pitch determined at said step (a);
(d) determining an algebraic value of a difference between a total actual length between the two end knives of the knife shaft, and a total theoretical length of the knife shaft calculated by multiplying the total number of different pairs of consecutive knives by the value of the theoretical pitch;
(e) determining an algebraic value of the difference for the length per knife by dividing the algebraic value of the difference between the total theoretical length and the total actual length obtained at said step (d) by the total number of knife pairs of the knife shaft;
(f) determining an algebraic value corresponding to a second corrected relative position of each of the knives by adding the algebraic value of
(g) the difference for the length per knife to the algebraic values corresponding to the first corrected relative position;
and
(h) from the sum of the algebraic values of the second corrected relative position, determining quantities of material to be removed per knife.

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Abstract

Claims8