Linkage assembly for a damper

A linkage assembly 10 for operating a damper 100 comprises an input member 12 (shaft) for transmitting a rotary movement and a rotary movement output member 18 connectable to a damper blade (120, fig 2). A linkage bar 16 connects the input member to the output member, and wherein rotary movement of the input member translates rotation of the output member through the linkage bar. A connecting part 20 (blade drive bar) connects a first end 30 of the linkage bar to the output member and wherein rotation of the connecting part varies the distance between the first end of the linkage bar and the output member and thereby increases the speed of the rotation of the output member as the distance between the first end of the linkage bar and the output member is reduced. The linkage bar is also connected to the input member by a drive bar 24 rotatably fixed at one of its ends to the linkage bar and fixed at the other of its ends to the input member. Distance variation may be via a cam 26 moveably connected to the linkage bar first end, which is restricted to travel within a cam slot 28.