Patent ID: 8522397

Claim:
A castor, comprising: an upright support shaft; a stop ring secured on the support shaft and having an outer wall provided with a toothed first locking portion; a castor body rotatably mounted on the support shaft; two rollers rotatably mounted on two opposite sides of the castor body by a mandrel and each having a side provided with a toothed second locking portion; a locking module movably mounted on the castor body and movable to engage the first locking portion of the stop ring and the second locking portion of each of the rollers; and a control wire movably mounted on the support shaft and connected with the locking module to move the locking module relative to the stop ring and each of the rollers; wherein the locking module is movable in concert with the control wire and has a first end provided with a first locking member and a second end provided with a second locking member; the first locking member of the locking module has a top face provided with a toothed first engaging portion that is movable to engage the first locking portion of the stop ring so as to lock the first locking member of the locking module onto the stop ring; the second locking member of the locking module has two opposite sides each having a top provided with a toothed second engaging portion that is movable to engage the second locking portion of a respective one of the rollers so as to lock each of the rollers onto the second locking member of the locking module.