| 摘要 |
The castor fork (23) of a castor (10) is pivotably mounted on a bearing element (11) arranged at the foot of the device and comprising a pressure-medium cylinder (12). Arranged in the castor fork (23) is a braking member (34) which acts upon the castor wheel (40) and on a blocking disc (36) which is connected to the bearing element (11) in a rotationally fixed manner, which braking member can be actuated by means of a piston (28) guided in the pressure cylinder (12). The pressure-medium cylinder (12) of the castor (10) is connected to a central pressure-generating piston-actuated control unit (42) by means of a pressure-medium line (16), which control unit is however only capable of producing two operating positions, that is to say a release position and a braking position. A blocking device is intended to be provided by means of which, in addition to the release of pivoting movement of the castor fork (23) and rotary movement of the castor wheel (40), as well as the total blocking of both movements, a pressure-medium-controlled position determining solely the running direction of the castor (40) can also be triggered. …<??>The control unit (42) comprises in each case a piston/cylinder unit (43) which is assigned to each castor (10) and which can be actuated by a central control cam (50), with which unit each pressure-medium cylinder (12) of each castor (10) can be supplied with an itemised amount of pressure medium. …<??>This possibility of pressure-medium metering for more than two end positions guarantees a pressure-medium-controlled third position for fixing the direction of the castor wheel (40). …<IMAGE>… |
