Torsion Balance

Torsion Balance, textile scale, type No. 5000, No. 6656, with die and mallet, by the Torsion Balance Company, New York, United States, 1902-1915.

These scales are for finding the weight of cloth, expressed in both the English and the metric systems. The feature of the construction is that in place of ordinary knife edges there are three taut steel tapes. In the original form, patented in 1882 by Roeder, steel wire was used. The tapes are stretched over frames, one of which is rigidly fixed to the base plate and forms the fulcrum, while the other two connect the ends of the two beam members, so that any displacement, due to a weight on one scale, causes twisting of the tapes. Adjustable poises are mounted on the beam, and these partly neutralise the torsional resistance, and so increase the sensitiveness of the scales. The scales shown are a modification without loose weights. First the scales are brought to zero by the weight at the left. A sample 2 in. square, cut from the cloth to be tested by the punch and mallet shown, is then placed with its right- hand edge at the graduation on the carrier that corresponds with its woven width. The scales are then again brought to zero by sliding the weight on the graduated beam and the weight in oz. per yd. or gram. per metre, to an accuracy of o.2 oz. or 5 gram., can be read off.