Abstract: A device for elongating long bones such as thigh bones, shin bones and arm bones, including an intramedullary nail with a tubular sleeve (4), and an extension (5) axially slidable within the sleeve (4). The sleeve and the extension include means (6; 7) for rigidly connecting them to two bone portions separated by an osteotomy, and means for moving the extension (5) relative to the sleeve (4), whereby both the intramedullary nail and the corresponding bone may gradually be elongated. The means for moving the extension (5) relative to the sleeve (4) include an electric motor (8) arranged within the sleeve (4) and linked to a speed reducer (9) driving a screw/nut assembly (13, 14, 15) for moving the extension (5) relative to the sleeve, and means (2) for supplying power to the electric motor (8) and automatically controlling the value and direction of the movement imparted to the extension (5) in the sleeve (4) by the screw/nut assembly (13, 14, 15) driven by the electric motor (8).

Abstract: A control device for controlling the movements of first and second recording means support-carriages of a two-carriage duplex recorder, comprising a flexible elongated traction means connected to said first carriage, and drive means associated with said traction means for moving said first carriage selectively in two opposite directions, wherein coaxial first and second wheels are mounted for rotation as a unit on said second carriage about an axis at right angles to said two opposite directions, said first wheel being in driving relationship with said traction means so as to be rotatively driven thereby, and an elongated fixed reaction member extending in a parallel direction to said two opposite directions and being in engagement with said second wheel to cause the latter and said second carriage to move along said reaction member upon rotation of said first and second wheels.