Patent attributes
A castor structure includes a wheel support unit, an operation unit, a locking member, a directional member, a directional brake member, a bent elastic bar, and two resting members. The operation unit includes a drive shank formed with an annular groove which has an upper tapered face and a lower tapered face. The locking member includes a plurality of locking teeth. The directional brake member includes a plurality of directional toothed grooves. The elastic bar extends through the directional member and the annular groove. Thus, the elastic bar is stretched outward by the annular groove of the drive shank when the drive shank is moved downward, to provide a micro-adjustment effect, such that the directional toothed grooves of the directional brake member align with and exactly engage the locking teeth of the locking member.
