GB1395177A - Precision laboratory balance - Google Patents

Abstract

1395177 Precision balance TORSION BALANCE CO 16 July 1973 [28 July 1972] 35399/72 Heading G1W A precision balance comprises a balance beam 10 pivoted at 14 to a frame 12, a truss 20 pivoted at 18 to the beam 10 and carrying a weighing pan 22, and a lower link 32 attached to the truss 20 and frame 12 by means of torsional pivots 28, 30, the lower pivots 28, 30 being less torsionally rigid about axes other than their pivot axes than the upper pivots 14, 18. Each torsional pivot may comprise a torsion stop 28, 30 clamped at its ends to the truss or frame and clamped in the middle to link 32. Alternatively the torsion strips may be clamped at their ends to the link 32 and in their middles to the truss and frame. The torsion strips may be adjustable vertically and the length of the link 32 may be adjustable. Provision may be made for adjusting the tension in the torsion strips to alter the sensitivity of the balance. The link 32 may be pivotally attached to the torsion strips by means of ball bearings Fig.4 (not shown). The torsion strips may be of beryllium copper alloy or stainless steel. The upper pivots 14, 18 may be of the knife edge type as shown in Fig.1, or may be of the crossed flexure strip type Fig.2 (not shown). A graticule 16 co-operates with a light beam to allow the deflection of the beam to be read off.