Hagati ya 1926 na 1933, NielsA Christensen wo muri Danemark wavumbuye kandi akora imashini yarushijeho gutera imbere no gushyira mu bikorwa ubu bwoko.Ubuhanga bwe (O-ring) bwasohowe mu 1930, butangwa mu 1933, kandi butwara igihembo kinini mu 1938.
Igihe cyo kohereza: Ugushyingo-07-2022
