GB587488A - Concrete mixer - Google Patents

Abstract

587,488. Mixing-machines. DEHN, F. B. (Chain Belt Co.). Sept. 27, 1944, No. 18473. [Class 86] In a concrete mixer comprising a rotatable mixing drum, a charging hopper movable to and from a position adjacent the drum, and an annular member interposed between the hopper and the drum and mounted rotatably on either hopper or drum, means are provided for ensuring relative rotation between the annular member and its supporting element whilst preventing, by means independent of friction, relative rotation between the annular member and the other element. Contact between the drum 11, Fig. 2, and the hopper 29 is sealed by an annular bearing element 30, which, in the discharging position of the hopper 29 may rotate with the drum 11 through the frictional engagement of the contacting surfaces. The hopper 29 is moved from its discharging to its charging position by a handwheel geared to the shaft 55 of a crank arm 56 connected to one of a pair of arms 50 which are mounted on a pivoted shaft 40. The lower end of each arm 50 is pinned to an extensible link 51 which exerts pressure through a spring loaded arm 52 connected to a trunnion 53 mounted on the side of the hopper. As the hopper moves towards the drum the crank 56 rotates through linkage 66, 65 a sleeve 63, Fig. 4, on the shaft 40, and a pin 62 thereon contacts a lug 60 on the surface 59 of the ring 30 and prevents the rotation of the ring when the hopper is in the charging position. The drum is mounted for rotation about an inclined axis and carries a track 16 which is spaced outwardly from the drum by means of a relatively flexible web 69 and which is rotatable on rollers 17. A discharge shoot 28 is mounted with its centre offset with respect to the vertical plane through the axis of the drum. In a modified construction the hopper is supported by a bracket extending radially from the upper edge of the discharge opening of the hopper and fixed to a shaft mounted in bearings disposed axially within the mixing drum; and a vibratory plate is hingedly mounted on a wall of the hopper in order to loosen material which might prevent the escape of air from the drum during charging.