Roberval balance

A bar scale is a weighing device to determine the weight of an unknown mass by direct comparison with the weight of a known mass. With the panel scales the mass of a body is determined by comparison with standard weights.

Description

As a simple beam balance, including the balance board has an equal-armed balance beam. In contrast to this, however, it has no hanging on the balance beam scales, but panels ( platforms) or shells, which have a lower beam (plate scale to Roberval ) or with levers on each panel ( panel balance according to Beranger ) are mounted on the balance beam. The balance beam is located at the board level always below the panels.

The agreement of the mass of the sample to the mass of the applied standard weights can be of metal flags that are attached to the boards, read.

The properties of the panel scales differ from those of the simple beam balance the fact that the position of the sample and the standard weights on the respective panel not affect the weighing result. In the simple beam balance, however, the weighing result is influenced by the relative position of the mass in the pan.

Platform scales are commonly used in the weighing up to ten kilograms.

History

The panel scale was in 1669 by the French mathematician Gilles Personne de Roberval ( born August 10, 1602 Roberval, Senlis, † October 27th 1675 in Paris) invented. While Roberval balance still had a lower beam, that of the mechanic Joseph Beranger (* 1802, † 1870) in 1847 was replaced by two levers. Both skew and site movements are better compensated in the Beranger - scale, which significantly expands the possibilities to use the panel scales.