Abstract: An elastic joint for the transmission of motion between a driving shaft and a driven shaft, comprising in effect two tetrahedrons joined together along one edge.The two tetrahedrons are constituted by eight edges formed by flexible elements resistant to tensile stresses; the furthermost edges and the joining edge are formed of material resistant to compression stresses.

Abstract: A mechanical starter for internal combustion engines in which the energy necessary to start the internal combustion engine is provided by elastomeric elements which are stretched by winding them around a nucleus composed of a plurality of mutually contacting washers is disclosed.

Abstract: A device for storing and later releasing mechanical energy has an elongate body, preferably cylindrical, at least one elastic strip or band wound helicoidally about the body and fastened thereto at each end thereof. A rigid rod extends longitudinally through and supports the body. The strips are wound about the body by rotating one end of the body on the rod. The strips of elastic material are subjected only to tensile stress and can be greatly deformed to accumulate a large amount of energy. The dimensions of the device are relatively small and need not be varied to accumulate a large amount of energy. The device is useful for starting an internal combustion engine, a rechargeable element as a substitute for a motor or as an accumulator of braking energy of a motor vehicle.