William T Dalebout, Sohrab Vassoughi, William J Martinell, David C Rohrer, Steven W Martinell, Robert L Marchant: General purpose exercise machine. Pro Form, Klarquist Sparkman Campbell Leigh & Whinston, August 4, 1987: US04684126 (87 worldwide citation)

An exercise machine having a frame supporting a seat in an off-the-floor position. A pair of arm levers are mounted on the frame and provide resistance to movement in two directions, with the resistance to pushing from rest positions being less than the resistance to pulling to return the arms to th ...