Standard accurancy on chain lenght
The finished, unlubricated chain to be measured must be supported along its entire length and subjected to a measuring load equivalent to approximately 1% of the minimum breaking load.
The degree of accuracy of the chains differs according to the types listed below.
Agriculture chains (ISO 487 Norm)
The length must be equal to the nominal length, with a limiting deviation of 0/+0.30%, which equals 0/+3 mm/m
Heavy conveying chains (ISO 1977 Norm)
The lenght must be equal to the nominal lenght, with a limiting deviation of 0/+0,25%
Rollers precision chains, short pitch (ISO 606 Norm)
Rollers precision chains, long pitch (ISO 1275 Norm)
Bushes precision chains , short pitch (ISO 1935 Norm)
The lenght must be equal to the nominal lenght, with a limiting deviation of 0/+0,15%
Otherwise, for the same chains with attachments (attachment or hollow pins) the length must be equal to the nominal length with a limit deviation of 0/+0.30%.
Coupling is a further operation that follows the pre-stretching stage and consists of selecting pairs of chain lenghts that have a linear development within a certain range, which will form chain links arranged in parallel for particular applications where high precision is required.
The degree of coupling accuracy can be standard, in other words a manual visual coupling. In this case, the chain lenghts are usually tied together or appropriately numbered in pairs 1-1,2-2, 3-3 etc. Or one can opt for a more accurate measurement and classification using digital equipment that guarantees higher accuracies. In this case, the lengths are labelled and numbered and a coupling model is provided to the customer together with the necessary instructions.
For the most appropriate choice of coupling grade, please contact our Technical Department.
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