Trolley wheel assembly

A trolley wheel assembly (10) securely sealed to prevent loss of lubricant from within the assembly (10) and entrance of contaminants into the assembly (10) over extended operating periods, said assembly (10) comprising:

• an inner race (12) disposed about an axis of rotation (14);
• an outer race (16) concentrically disposed in a spaced relationship about said inner race (12);
• a plurality of ball bearings (18) disposed radially between said inner race (12) and said outer race (16) to permit said outer race (16) to rotate about said inner race (12);
• an outer sealing ring (20) fixedly mounted to said outer race (16) and extending radially inwardly toward said inner race (12);
• an inner sealing ring (22) rotatably disposed about said inner race (12), extending radially outwardly toward said outer race (16) and contiguous said outer sealing ring (20);
• biasing means (24) disposed about said inner race (12) for biasing said inner sealing ring (22) into constant friction engagement with said outer sealing ring (20);
• and
• characterized by at least one backup inner sealing ring (26) rotatably disposed about said inner race (12) between said biasing means (24) and said inner sealing ring (22) to provide a secondary seal around said inner race (12) as rotation of said inner sealing ring (22) against said inner race (12) produces wear on said inner sealing ring (22) and a less secure fit about said inner race (12).