SPAN ADJUSTING DEVICES FOR WEIGHING MACHINES

摘要

In an automatic weighing apparatus of the type in which the load of a weighing hopper containing articles to be weighed is applied to a corresponding weighing mechanism through means of a support member (25) adapted for supporting the weighing hopper, and in which the weight is derived as the magnitude of the output signal from a displacement sensor provided on the weighing mechanism, a span adjusting device (15) is provided which includes a reference weight rest (27) which is secured to the support member (25) and on which a reference weight (34) may be placed so that the span weight constituted by the reference weight is applied to the weighing mechanism through means of the support member (25). A vertical displacement mechanism (28) includes an operating bar (30) passed through the reference weight rest (27) and vertically movable therethrough in such a manner that the reference weight (34) is supported entirely on the end of the operating bar (30) when the bar projects above the weight rest but is removed from the end of the operating bar and supported freely by the weight rest (27) when the bar (30) is moved to a position below the weight rest. Such an arrangement makes it possible to simplify a span adjustment facilitating accuracy and rapidity in carrying out such adjustments.