| 摘要 |
A caster structure for cases including a coupling frame and a plurality of rollers. The coupling frame is comprised of a curved plate and two protective covers extending from the lateral edges of the bottom side of the plate such that they define a clearance therebetween. The rollers are pivotally mounted on the protective covers in the clearance. The outer circumferences of every two adjacent rollers form a level line and may come into contact with the ground surface simultaneously to facilitate pulling and provide a steadier movement.
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