(57) A scrap ejector comprises a pneumatic motor imparting a vibratory motion by means
of a first piston that is arranged to reciprocatingly slide within a first cavity
of an outer body owing to the action of an elastic spring or an adjustable, but substantially
constant pneumatic force acting on a side of said piston, and a pulsed pneumatic force
acting on the other side thereof. This pulsed force is obtained by applying a pneumatic
pressure onto said other side of the piston, while alternately cutting off and re-establishing
said second force by means of a valve arrangement based on a second piston adapted
to slidably reciprocate within a respective cavity, wherein the opening and closing
stroke of this second piston for applying and exhausting the pressure acting upon
said first piston is controlled, i.e. actuated in a direct manner in one direction,
and in an indirect manner in the opposite direction, by the same reciprocating displacement
of said first piston.
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