| 摘要 |
A caster or dolly for placement under a heavy object that is intended to be moved across a floor or other surface; the dolly including a spring-loaded, telescopic arm which at each opposite end is supported upon a rotatable roller mounted on an axle that can selectively be placed so that both axles are either parallel or else arially aligned in order that the dolly can travel in either of two directions at right angle to each other, and each roller being vertically adjustable between an operative and an inoperative position by means of a rotatable cam resting upon the opposite ends of each axle. |
