Abstract: An operating lamp has at least one main bulb 11 arranged at a desired position 13 and a replacement bulb 12 arranged at a waiting position 14 located close the desired position 13. The main bulb 11 and the replacement bulb 12 are displaceably mounted and controlled in such a way that when the main bulb 11 burns out it is moved away from the desired position 13 and the replacement bulb 12 is moved from the waiting position 14 to the desired position 13 and is held there. The main bulb 11 and the replacement bulb 12 are mounted on holders 15, 16 which are moveable independently of one another.

Abstract: A joint support structure comprising means forming a housing defining a chamber embodies an axially movable wall portion constituting a clamping device which forms one wall portion of the chamber. This chamber contains radially movable means and means responsive to movement of the axially movable wall portion to induce or accommodate a radial shift of said radially movable means. Means projecting outwardly of the housing includes a rod axially movable in response to movements of said radially movable means to clamp a related joint element to or release the related joint element from a defined seat.Various arrangements are provided to constitute the means responsive to movement of the axially movable wall portion, each of which dictates that essentially the total of the applied forces are translated into a direct radial movement of the rod or rods associated with the joint support structure.