US Patent 7540653 Mixing machine and associated sealing arrangement for bearings

A mixing machine includes a head extending over a bowl receiving location. The head includes a shaft receiving opening extending upwardly therein and a rotatable mixing shaft having a lower portion extending below the head and an upper portion within the shaft receiving opening. An upwardly facing bearing shoulder is within the shaft receiving opening. An upper bearing member is disposed within the shaft receiving opening and about the mixing shaft. The upper bearing member is supported by the upwardly facing bearing shoulder. A gear system is in the head for effecting planetary movement of the mixing shaft. The gear system includes a gear member disposed about an upper end of the mixing shaft and linked to the upper end of the mixing shaft for effecting rotation of the mixing shaft. The gear member is supported by an upper side of the upper bearing member and the shaft is supported by the gear member. An upper seal is located at least partially in the shaft receiving opening and positioned above the upper bearing member. The upper seal includes a radially inner lip that is biased against an outer surface of the gear member.