GB623750A - Improvements in hydrostatic balances - Google Patents

Abstract

623,750. Weighing-apparatus. LANGE, B. G., and LANGE, K. H. July 19, 1946, No. 21646. [Class 143] A hydrostatic weighing apparatus suitable for tolerance measurement comprises a float 10 in a liquid filled vessel 11 which has secured to it an auxiliary member 14 of relatively small cross-sectional area dipping into an open cup 15 carried by the float 10. The auxiliary member 14 is shown as a tube providing an outlet for a rod 13 which connects the weigh pan 12 to the float and also carries the cup 15. A normal load 16 on the pan 12 is substantially balanced by the float 10, and small variations in load are balanced by vertical displacement of the float and the parts 12, 13 and 15 carried by it, such displacement varying the hydrostatic upthrust on the tube 14 and the downward reaction thereof on the cup 15 to restore equilibrium. An annular pointer 25 on the cup 15 indicates the weight against a fixed scale 24 and is adjusted to read correctly by turning a screw 22 to raise or lower the cover 17 of the vessel 11, the cover being connected to the vessel by a bellows 18. Effects of temperature change may be nullified by suitable selection of materials for the vessel and float, and of the liquid employed. The float may be of hard rubber and the liquid a mixture of glycerine and water. In a modification, Fig 3 (not shown), the rod 13 is connected by a flexible band and pulley to a rock shaft which carries a depending indicator pointer. This pointer acts pendulum-wise to counterbalance the variations in load either wholly (the tube 14 then having a very small diameter) or in conjunction with the tube 14. In Fig. 4 (not shown) a separate pendulum, additional to the pointer is provided on the rock shaft, and the load platform is connected to the rod 13 through a conventional lever system beneath the platform.