PURPOSE: To make it possible to surely turn a wheel to the advancing direction by receiving the reaction force of a ball by means of a pair of wheels disposed above the ball housed in a ball supporting cylinder and contact points of the ball with inner surfaces, which are in the opposite side of the advancing direction, of the ball-supporting cylinder.
CONSTITUTION: A turnable wheel 9 is provided with a cylindrical ball-supporting cylinder 11 which comprises a cylinder part 11a, a fitting base 11b for a truck or the like, fitting holes 11c, inserting holes 11d for ball bearings 13, and a projection 11e. A ball 10 is housed in the ball-supporting cylinder 11 in such a manner that a part of the ball projects downward. Above the ball 10 housed in the ball-supporting cylinder 11 is mounted a small-wheel frame 12 comprising supporting parts 12a for a pair of small wheels 14a and 14b, a swivel shaft 12b and a flange part 12c which are integrally formed with each other. The small- wheel frame 12 is turnably supported by the ball bearings 13. The reaction force of the ball 10 is thus received by a pair of small wheels 14a and 14b, and contact points P1 and P2 of the ball 10 with inner surfaces, which are in the opposite side of the advancing direction, of the ball-supporting cylinder 11, and accordingly the ball 10 is surely turned to the advancing direction.
| WO/2004/081396 | ARRESTING DEVICE OR BALL CASTER |
KANEKO KAZUO
OGASAWARA HITOSHI
WATABE MITSURU
