| 摘要 |
PURPOSE:To intend to improve the durability and turning performance and to lighten the device by penetrating a thrust shaft into a top portion of a fork holding a wheel for holding an inner race of a rolling bearing between the thrust shaft and the fork while holding an outer race similarly between a base plate and a socket. CONSTITUTION:A main portion of a caster 15 is constituted of a base plate 16, socket 17, fork 18, rolling bearing 19, thrust shaft 20 and a nut 21. In this case, the thrust shaft 20 is penetrated into a top portion 30 of the fork 18 holding a wheel 35 having a horizontal axial line 34. And the inner rave 19a of the rolling bearing 19 is held between the head part 20a of the thrust shaft 20 and the head part 30 of the fork 18 and then tightened up with the nut 21 and the like. And again the outer race 19b of the rolling bearing 19 is held and fixed by the boss integrally formed with the base plate 16. According to this construction, the base plate 16, fork 18 and wheel 35 are made possible to turn mutually around the shaft portion 20b of the thrust shaft 20. Therefore, respective parts can be manufactured separately, simply and also cheaply.
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