Screening machine with acceleration modification

Abstract

A screening machine of the type used to separate or classify mixtures of solid particles of different sizes includes a fixed base and a perforate screen deck mounted for movement relative to the base during a screening operation. Leaf springs connect the tail end of the screen deck to the fixed base so that the leaf springs support the tail end of screen deck for movement relative to the base. The leaf springs are oriented horizontally to avoid introducing vertical movement to the screen deck as it moves to and from the head and tail ends. The leaf springs are offset or deflected when the machine is at rest or in the neutral mid-point of its stroke. This arrangement advantageously utilizes the bias of the leaf springs to accelerate, assist or enhance movement of the screen deck during portions of its stroke and likewise to decelerate, hinder or retard the movement during other portions of its stroke. With an appropriate offset, an increase in the effectiveness of the screening process (i.e., fewer defective particles passing through the screen deck) while a decrease in the screening time is attained.