| 摘要 |
The invention relates to a steering castor unit intended primarily for hospital beds. The steering castor unit has a bearer (10) with two castors (14) fitted on a common axle and a hollow shaft (18) fitted on the bearer to pivot about a vertical axis. In the hollow shaft (18) there is an axially movable control rod (26) by means of which, by adjustment on a cam disc (28), the rotary movement of the castors (14) and the swivelling movement of the hollow shaft (18) may be locked or freed together or the running direction of the castors (14) in relation to the hollow shaft (18) can be blocked in a predetermined straight-ahead direction. In order to ensure a stable bearing arrangement for the hollow shaft (18) with properly designed force transmission and reliable operation in all circumstances, the control rod (26) is a pushrod, while the hollow shaft (18) bears a control ring (56), secured in rotation to the hollow shaft (18) and axially movable to a limited extent against the force of a spring (40) acting towards the cam disc (28). On its side facing the cam disc (28), the control ring has an anti-pivoting pawl (58) which can engage in a recess (60) in the bearer and on its side opposite the pawl (58) it has a peripheral conical control surface (88). On the bearer (10) there is a locking lever (68) actuatable via the control surface (88) of the control ring (56) having a locking member (76, 87) on each of its lever arms, one of which can be engaged with a locking drum (82) integral with the castor and the other with a locking drum (52) integral with the hollow shaft at the same time. |
