| 摘要 |
A castor comprises a moulded plastics body (1) having a socket for a swivel pin and a center wall (6) with an aperture of which the edge is formed as the outer ball track (9) of a ball bearing. Two moulded plastics wheels (2) have hollow hub portions (11) extending towards the center wall and shaped to co-operate to provide the inner ball track (17) of the ball bearing. |
