Apparatus for mixing molding sand

A molding sand mixer comprising an elongated tub having an arcuate bottom, an elongated shaft extending axially within the tub, a series of paddles mounted on the shaft and extending radially toward the tub wall, power means for rotating said shaft, said paddles having blade and shank portions, at least said blade portions being disposed at an oblique angle to the tub axis to advance sand along the tub when the shaft rotates, the blade portions of the paddles having a greater circumferential extent than the shank portions, the aggregate circumferential extent of said blade portions at least almost filling the space around the periphery of said arcuate bottom of the tub when viewed in end elevation, there being substantial gaps between said shank portions of the paddles when viewed in end elevation, whereby the blade portions will substantially completely sweep the arcuate bottom of the tub, but some of the sand in the vicinity of the shanks may be missed by the shanks and be bypassed, means to restrict sand flow through the tub, thus to control sand retention time in the mixer, said means comprising a disk gate on said shaft at the discharge end of the tub.

A molding sand mixer comprising an elongated tub having an arcuate bottom, an elongated shaft extending axially within the tub, a series of paddles mounted on the shaft and extending radially toward the tub wall, power means for rotating said shaft, said paddles having blade and shank portions, at least said blade portions being disposed at an oblique angle to the tub axis to advance sand along the tub when the shaft rotates, the blade portions of the paddles having a greater circumferential extent than the shank portions, the aggregate circumferntial extent of said blade portions at least almost filling the space around the periphery of said arcuate bottom of the tub when viewed in end elevation, there being substantial gaps between said shank portions of the paddles when viewed in end elevation, whereby the blade portions will substantially completely sweep the arcuate bottom of the tub, but some of the sand in the vicinity of the shanks may be missed by the shanks and be bypassed, means to restrict sand flow through the tub, thus to control sand retention time in the mixer, said means comprising a series of paddles having reverse pitch blades on said shaft at the discharge end of the tub.

A continuous molding sand mixer comprising an elongated tub having a head end and a tail end, an elongated shaft extending axially with the tub, an entry port at the head end of the tub and a discharge opening at the tail end of the tub, a series of paddles mounted on the shaft substantially equidistant therefrom and adjacent the tub wall, power means for rotating the shaft, most of said paddles being forwardly pitched in one direction to advance sand along the tub from its head end toward its tail end and out said discharge opening when the shaft rotates, some of said paddles being reversely pitched in the opposite direction and disposed in the path of sand impelled by the forwardly pitched paddles to restrict sand flow through the tub, thus to control sand retention time in the mixer and restrict premature discharge thereof through said discharge opening.

A continuous molding sand mixer comprising an elongated tub having a head end and a tail end, an elongated shaft extending axially within the tub, an entry port at the head end of the tub and a discharge opening at the tail end of the tub, a series of paddles mounted on the shaft, power means for rotating the shaft, most of said paddles being pitched in one direction to advance sand along the tub from its head end toward its tail end and out said discharge opening when the shaft rotates, some of said paddles being reversely pitched to restrict sand flow through the tub, thus to control sand retention time in the mixer and restrict premature discharge thereof through said discharge opening, said tub wall being lined with a resilient material and said paddles being provided with resilient edges, said resilient material and said resilient edges coacting to inhibit sand encrustation of said wall.