Shaft coupling with variable timing

Device for coupling together two coaxial rotary shafts and permitting of varying within certain limits the relative angular timing of said shafts under running conditions, notably for driving the valves of internal combustion engines, which comprises a sliding member adapted to move axially in relation to said shafts for varying their relative angular timing, said device further comprising a bevel gear rotatably integral with one shaft, at one end thereof, a pair of toothed segments having bevel teeth in constant meshing engagement with diametrally opposed portions of said bevel gear, said segments being pivoted by means of a diametral pin carried by the other shaft, each bevel-toothed segments being rotatably solid with a lever having a fork-shaped cavity engageable by a driving pin carried by said sliding member, the cavities of said levers being diametrally opposed and disposed on either side of said other shaft, whereby any movement of translation impressed to said sliding member is attended by opposite angular movements of said bevel toothed segments, thus varying the relative angular timing of said shafts.