Combination castor brake system whose castor assemblies are braked and positioned simultaneously

A combination castor brake system, comprising:

• a linking device;
• and
• a plurality of castor assemblies connected with the linking device;
• wherein each of the castor assemblies comprises:
• an operation unit;
• a braking unit connected with the operation unit;
• and at least one roller connected with the braking unit;
• the operation unit of each of the castor assemblies includes:
• a mounting seat having an interior provided with a slideway;
• a slide slidably mounted in the slideway of the mounting seat and having a first end provided with a connecting portion pivotally connected with the linking device and a second end provided with a pressing ramp;
• and
• at least two limit rods each extended through the mounting seat and the slide;
• the mounting seat of the operation unit has two opposite sidewalls each provided with at least two through holes to allow passage of the limit rods;
• the slide of the operation unit has two opposite sidewalls each provided with at least two elongate limit slots slidable on the limit rods;
• the limit rods of the operation unit in turn extend through the through holes of the mounting seat and the limit slots of the slide;
• the connecting portion of the slide is driven by the linking device so that the slide of the operation unit is movable in concert with the linking device;
• the braking unit of each of the castor assemblies includes:
• a housing rotatably mounted on the mounting seat of the operation unit;
• a top cap mounted on the mounting seat of the operation unit;
• a control shaft movably mounted in the housing and having an upper end provided with a head pressing the pressing ramp of the slide and a lower end extended into the housing;
• an elastic member mounted on the control shaft and biased between the mounting seat of the operation unit and the control shaft;
• and
• a braking member secured on the lower end of the control shaft to move in concert with the control shaft and having a bottom provided with a braking portion that is movable to engage the roller;
• the braking member of the braking unit is received in the housing;
• the roller of each of the castor assemblies is rotatably mounted on the housing of the braking unit and is disposed under the braking portion of the braking member.