Central arm rest for a complex of at least two seats

A seat structure useful for transportation vehicles and embodying at least two, side-by-side seats with back rests, and an arm rest pivotally mounted on said seat structure between said side-by-side seats for pivotal movement in a vertical plane between a normal, horizontal orientation of said arm rest and a retracted position with said arm rest disposed in a space between said side-by-side seats, said seat structure being characterized by an arm rest having a rear element and a forward element which is a prolongation of said rear element, said rear element having a width such that it will fit in the space between said seats and said forward element having an arm support surface of a width wider than said rear element and wider than said space between said seats and a depth such that said forward element will fit in said space between said seats, means pivotally mounting would rear element on said seat structure to effect said pivotal movement of said elements in unison between said normal, horizontal orientation of said arm rest and said retracted position in the space between said seats, and means for rotating said forward element with respect to said rear element through an angle of 90.degree. about an axis extending longitudinally of said forward element between a first orientation of said arm support part wherein its width is in a horizontal plane and said arm support part can serve comfortably as an arm rest for both seats and a second orientation wherein said arm support surface is in a substantially vertical plane, whereby said forward element will fit in the space between said seats upon pivoting said arm rest to said retracted position.