Systems, methods, and devices are provided for redundant control of parallel inverter installations. The reconfigurable shield is applicable in the medical field, in the aerospace industry, in mobile radiological laboratories and decontamination vehicles, as well as in other fields where intensity-fluctuating radiation and variable direction radiation represent a hazard. A face of the second coupling member has locking formations that are engaged by struts upon projecting outwardly from the pockets to prevent relative rotation of the first and second coupling members with respect to each other in at least one direction about the axis.