초록 ▼

A castor includes a castor body, an operation unit, a locking unit, and two rollers. The operation unit includes a pressing plate and a rotation member. The locking unit includes a locking module, a stop ring, a locating member, and an upper positioning plate. The locking module has a locking member

A castor includes a castor body, an operation unit, a locking unit, and two rollers. The operation unit includes a pressing plate and a rotation member. The locking unit includes a locking module, a stop ring, a locating member, and an upper positioning plate. The locking module has a locking member and a braking member. When the driving portion of the rotation member presses the first ramp of the pressing plate, the locating member is locked in the locking hole of the upper positioning plate. When the driving portion presses the second ramp of the pressing plate, the first engaging portion of the locking member engages the first locking portion of the stop ring, while the second engaging portion of the braking member engages the second locking portion of each of the rollers.

대표청구항 ▼

1. A castor comprising: a castor body, an operation unit, a locking unit, two rollers, a mandrel, and a bushing;wherein:the operation unit includes a support tube, a control rod, a housing, a pressing plate, a rotation member, a first elastic member, and an operation handle;the support tube of the o

1. A castor comprising: a castor body, an operation unit, a locking unit, two rollers, a mandrel, and a bushing;wherein:the operation unit includes a support tube, a control rod, a housing, a pressing plate, a rotation member, a first elastic member, and an operation handle;the support tube of the operation unit has a top provided with at least one slideway;the control rod of the operation unit is movably mounted in the support tube;the control rod of the operation unit has a top provided with a receiving groove;the control rod of the operation unit has a bottom provided with a fixing portion;the fixing portion of the control rod has an interior provided with a screw bore;the housing of the operation unit is mounted on the support tube;the housing of the operation unit includes two shells which encircle the control rod and the support tube;the housing of the operation unit has an inner face provided with at least one limit flange and has a peripheral wall provided with at least one through hole;the pressing plate of the operation unit is partially received in the receiving groove of the control rod and is movable in the slideway of the support tube;the pressing plate of the operation unit has a top provided with a first ramp, a second ramp and an arcuate dimple;the first ramp of the pressing plate has a height greater than that of the second ramp;the arcuate dimple of the pressing plate is located between the first ramp and the second ramp;the rotation member of the operation unit is rotatably mounted in the housing and is disposed above the pressing plate;the rotation member of the operation unit has an interior provided with a fixing hole and has a periphery provided with a first limit ear, a second limit ear and a driving portion;the fixing hole of the rotation member is fixed on the operation handle;the rotation member is rotatable in concert with the operation handle;the driving portion of the rotation member is received in the arcuate dimple of the pressing plate and is movable to press the first ramp and the second ramp of the pressing plate;each of the first limit ear and the second limit ear of the rotation member is movable to abut the limit flange of the housing;the first elastic member of the operation unit is received in the support tube and is biased between the support tube and the control rod;the operation handle of the operation unit is extended through the through hole of the housing and the fixing hole of the rotation member;the castor body is swivelably mounted on the support tube of the operation unit;the castor body has a mediate portion provided with a mounting hole;the bushing is mounted in the mounting hole of the castor body and encircles the mandrel;the two rollers are rotatably mounted on two opposite sides of the castor body by the mandrel which is extended through the bushing;each of the two rollers is mounted on the mandrel and has a side provided with a toothed second locking portion;the locking unit includes a second elastic member, a locking module, a stop ring, a mounting sleeve, a third elastic member, a locating member, an upper positioning plate, a lower positioning plate, and a screw and washer assembly;the stop ring of the locking unit is secured on the support tube of the operation unit;the stop ring of the locking unit has an outer wall provided with a toothed first locking portion;the upper positioning plate of the locking unit is secured on a bottom of the castor body;the upper positioning plate of the locking unit has a first end provided with a locking hole and a second end provided with a first passage;the lower positioning plate of the locking unit is secured on a bottom of the upper positioning plate;the lower positioning plate of the locking unit has a first end provided with an exposing hole aligning with the locking hole of the upper positioning plate and a second end provided with a second passage aligning with the first passage of the upper positioning plate;the locking module of the locking unit has a first end provided with a locking member and a second end provided with a braking member;the locking member of the locking module has a top face provided with a toothed first engaging portion movable to engage the first locking portion of the stop ring;the control rod is extended through the locking member of the locking module and the mounting sleeve;the braking member of the locking module has two opposite sides each having a top provided with a toothed second engaging portion movable to engage the second locking portion of a respective one of the two rollers;each of the two opposite sides of the braking member has a surface provided with an elongate guiding slot slidable on the bushing;the braking member of the locking module has a bottom wall provided with a recessed protrusion;the protrusion of the braking member is movable to extend into the first passage of the upper positioning plate and the second passage of the lower positioning plate;the second elastic member of the locking unit is received in the protrusion of the braking member and is biased between the braking member of the locking module and the castor body;the mounting sleeve of the locking unit is mounted on the control rod and has a top abutting the locking member of the locking module;the locating member of the locking unit is mounted on the mounting sleeve;the locating member of the locking unit is movable to extend into the locking hole of the upper positioning plate;the locating member of the locking unit is locked by the upper positioning plate;the third elastic member of the locking unit is mounted on the mounting sleeve and is biased between the mounting sleeve and the locating member; andthe screw and washer assembly of the locking unit is screwed into the screw bore of the fixing portion of the control rod and abuts a bottom of the mounting sleeve. 2. The castor of claim 1, wherein: when the driving portion of the rotation member is movable to press the first ramp of the pressing plate, the pressing plate is moved downward to press and move the control rod which presses and moves the locating member with the locating member extended into and locked in the locking hole of the upper positioning plate to lock the castor body; andwhen the driving portion of the rotation member is movable to press the first ramp of the pressing plate, the second limit ear of the rotation member is movable to abut the limit flange of the housing to limit a further rotation of the rotation member. 3. The castor of claim 1, wherein: when the driving portion of the rotation member is movable to press the second ramp of the pressing plate to release the pressing plate and the control rod, the control rod is pushed upward by the first elastic member, the mounting sleeve and the locating member are moved upward by the control rod, and the locking member of the locking module is pushed upward by the mounting sleeve with the first engaging portion of the locking member moved upward to engage the first locking portion of the stop ring to lock the locking member of the locking module onto the stop ring, while the second engaging portion of the braking member is moved upward to engage the second locking portion of each of the rollers to lock each of the rollers onto the braking member of the locking module; andwhen the driving portion of the rotation member is movable to press the second ramp of the pressing plate, the first limit ear of the rotation member is movable to abut the limit flange of the housing to limit a further rotation of the rotation member. 4. The castor of claim 1, wherein when the driving portion of the rotation member is movable to extend into the arcuate dimple of the pressing plate, the control rod is pressed and moved downward slightly, and the mounting sleeve is moved downward by the control rod to release the locking member of the locking module, with the locking module released and moved downward by the second elastic member, the first engaging portion of the locking member is moved downward to disengage the first locking portion of the stop ring to unlock the locking member of the locking module from the stop ring, and the second engaging portion of the braking member is moved downward to disengage the second locking portion of each of the rollers to unlock each of the rollers from the braking member of the locking module. 5. The castor of claim 1, wherein the guiding slot of the braking member is slidable on the bushing when the braking member of the locking module is moved relative to the castor body to guide movement of the braking member.