Abstract: Rocks are known to contain minute cracks and fissures and such rocks can be crushed under less force than the ordinary crushing force when a vibrational force is applied to exert tension at the cracks and fissures. Rock crushers of the type which include hydraulic means connected to a crushing member are improved by adding means for superposing a vibratory force into hydraulic circuits of such crushers.

Abstract: The shell of the breakers is mounted on the upper part of the housing of a cone crusher in such a way that when expansion of the shell occurs under operation of the cone crusher the mounting bolts are not twisted or sheared and at the same time are readily accessible for replacement. Thus the shell is provided with a number of symmetrically spaced pockets around the middle part of its outer surface, each of these pockets extends through a corresponding opening in the casing and is connected to a mounting bolt for attaching to the casing through the intermediary of a two-arm lever directed radially away from the shell.

Abstract: In a mixing machine which has three sets of mixing blades, disk means for driving the sets one above the other, and all said disk means adapted to rotate about a vertical shaft in horizontal planes and to be driven by a single motor and wherein the disk of the middle set of blades is constructed to rotate in the opposite direction to the other two, a drive comprising a gearing unit protected by cover means is provided which is adapted to drive all the sets of blades from said vertical shaft. Said drive means comprising, gearing, disk means, cover, etc., is combined into a single unit so that it can be replaced as a unit.