SCALES INSIDE AND OUT

SCALES INSIDE AND OUT

The hundreds of scales available today for commercial use represent a wide range of special adaptations of one basic lever principle: the common see-saw. Scale maintenance is a simple task if the scale mechanic understands that any scale, from the most critical analytical balance to a heavy capacity railroad track scale, uses the same see-saw principle.

When a board fulcrumed over a pivot is centered, it will be at equilibrium when empty or when it carries a load as long as weights are properly placed. Scale errors are most often caused by improper leverage, improper weight location, or friction.

Biblical history gives the first clue to scales that were used in 5000 B.C.. These first scales were probably made with rope suspended from a wooden beam. Later, holes were drilled through the beam, and eventually, round metal loops were placed through the holes. Pivots or knives with metal loop bearings were introduced some 1000 years ago. Today's fine scales are the result of 7000 years of development. They are based on the same see-saw principle with refinements that include almost perfect knife edges, bearings, and alignment.

To meet the need of weighing commodities on platters located above the beam, Roberval's Enigma was developed in 1669. In principle, this scale is again the basic see-saw with a lower see-saw which acts as a check rod to keep the platters level. This innovation sped up hand weighing of small commodities, and the even balance scale has been improved in a number of ways over time.

We at TARE INC have been manufacturing scales for over 28 years, and thoroughly understand the theory of weighing devices. We manufacture and service all types of scales, from grams to thousands of pounds.

This excerpt was taken out of "Scales Inside and Out" written by TARE INC, and available at www.tare.com. Or call us at 800-237-6422. This manual is a scale inspection and repair manual for all types of scales, including mechanical scales.

Posted by Gail G. Nagle, TARE Inc.
www.tare.com
800-237-6422