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Screening machine

  • US 4,896,835 A
  • Filed: 06/30/1989
  • Issued: 01/30/1990
  • Est. Priority Date: 07/11/1988
  • Status: Expired
First Claim
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1. A screening machine for earth materials comprising:

  • a frame member;

    a screening drum mounted on said frame member and rotatable about a longitudinal axis;

    said screening drum having a screen peripheral wall with openings therethrough to separate the materials being screened as to size;

    means to support said drum for rotation about the longitudinal central axis with ends of the drum open to receive and discharge material to be screened;

    a first rotary brush having an axis parallel to the longitudinal axis and mounted on the interior of the screening drum and having bristles engaging the screen peripheral wall;

    a second rotary brush having an axis parallel to the longitudinal axis and mounted on the exterior of the screening drum and having bristles engaging said screen wall, the second brush being offset along the circumference of the screen peripheral wall from the first brush;

    beater means mounted for rotation on a central shaft within said screening drum and having a plurality of spaced beater flaps thereon, each comprising a flexible material flap fixed to the shaft and hammer means fixed to outer ends of the flap to engage material being screened; and

    means for rotating said beater means independently of rotation of the drum at a speed to cause the beater flaps to extend radially under centrifugal force to break up clods of the earth material, and the beater flaps being of size and mounted to move in a path adjacent to but clear of said screen peripheral wall of the screening drum and clear of the first brush as the beater means is rotated.

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