The shield is mounted on a central support which consists of e.g. four telescopic tubes (1-4). The telescopic tube has a handle at one end and a support (7) at the other end to which the support wires (8) for the shield are attached. The telescopic tubes have cross-sections which are shaped so that the tubes cannot rotate relative to one another. A coil spring (22) is mounted in the space in the top of the outer telescopic tube. The spring pre-loads the tubes into their extended positions and also acts as torque spring which twists the tubes, when they are extended, into bayonet type interlocks.
