Door opening and closing apparatus for tumbling barrel

A rotatable barrel for use in the surface treatment of particulate matter enclosed therein,

• said barrel having ends and side structure, said ends being mechanically attached to means forming the side structure,
• said side structure means being foraminous,
• an opening means in said foraminous side structure means for the insertion and discharge of particulate matter,
• said barrel being rotatable about an axis extending perpendicular to the ends of said barrel,
• a door for opening and closing said opening means, said door being mounted on lever arms,
• one said lever arm being spaced from each end of the barrel and extending radially from its axis of rotation, a hub means on each end of the barrel extending coaxially with said axis of rotation,
• said lever arms being mechanically attached to the hub means to thereby swing the door in an arc having an axis coaxial with said hub means,
• stop means for limiting the angle of said arc in which said door may swing relative to the barrel,
• at least one of said lever arms being mechanically attached to a gear mounted on one side of said hub means whereby, rotation of said gear in one direction drives the door to closed abutting position against one of said stop means and the barrel is thereafter rotated by force exerted by (1) the gear, (2) the attached lever arm and (3) the door pushing against the stop means,
• the stop means in abutment with the door comprising an L-shaped channel member welded to the periphery of said barrel adjacent one edge of the opening means and extending from one end to the other,
• the portion of the door abutting the stop means comprising a radially inwardly extending flange whereby the abutting flange and stop means serve to seal one edge of the opening against loss of the particulate matter during tumbling.