Abstract: The present invention relates to a bench grinder apparatus. The object of the invention is to provide a bench grinder apparatus and a method for safe and exact grinding of tools, and at the same time minimizing the damage to the tools and to the user during grinding. Bench grinder apparatus for grinding tools comprising: —at least one grinding wheel with a grinding surface arranged in a wheel casing, where the wheel casing is provided with one working opening which provides an access to a part of the grinding surface, —an operational means arranged in relation to said grinding wheel, capable of rotating the grinding wheel, —at least one tool rest moveably attached to the wheel casing, and arranged in a predefined distance to the grinding wheel, —at least one angle adjustable means capable of moving the tool rest in said predefined distance to the grinding wheel from a first grinding angle position to a second grinding angle position.

Abstract: The charging apparatus for lead-acid-accumulators controls the charging current and the charging voltage above the gassing voltage level according to a linearly declining characteristic. The charging current and the charging voltage are converted to a current signal (50) and a voltage signal (60) which are normalized (70, 80) and combined (150) into an indicating signal (160) which is constant as long as the charging current and the charging voltage follow the linear characteristic. A regulating device (130, 140, 40) compares the indicating signal (160) to a reference signal (132) for correcting the charging current and the charging voltage. The current signal (50) and the voltage signal (60) are converted to the indicating signal (160) by means of a weighted summation. For performing the summation there is provided an operational amplifier circuit.