GYRATORY CRUSHER

PURPOSE: To provide a gyratory crusher by which the production ratio of crushed products with grain size necessary to be crushed secondarily is lowered. CONSTITUTION: A gyratory crusher is made to have a structure wherein recessed parts 19, 19 whose width gradually becomes wider as going further toward a lower end part 4c from the position 4b of a chamfer for an object for crushing and, at the same time, whose maximum depth (h) is 0.5-1.0 times as deep as the deviated wear in the lower end part 4c of a concave 4 and whose maximum width W is 1.0-2.0 times as wide as the width (t) of arms 9, 9 and whose width is 26-32% of the total circumference of the lower end part of the concave 4 are formed in crushing face 4a of the concave 4 in the lower parts of the bases of the arms 9, 9. Consequently, the region except the regions of the recessed parts 19, 19 is more severely worn than the recessed parts 19, 19 and, until the time the concave 4 is changed with a new one, the deviated wear degree is kept within O.5 or the deviated wear degree is gradually lowered, so that crushed products of which 68-74% have a prescribed grain size or small are obtained.