US Patent 10206832 Swing arm linkage for a mid-wheel drive wheelchair

The present disclosure relates to a swing arm linkage (1) for a mid-wheel drive wheelchair, comprising: a first swing arm (3) having a first swing arm pivot point (3a) and a linkage member first mounting point (3b), a second swing arm (5) having a second swing arm pivot point (5a) and a linkage member second mounting point (5b), a linkage member (7) configured to be connected to the linkage member first mounting point (3b) and to the linkage member second mounting point (5b), to enable force transfer between the second swing arm (5) and the first swing arm (3), wherein the linkage member (7) has an elongated shape defining a linkage axis (A) extending between the linkage member first mounting point (3b) and the linkage member second mounting point (5b), a first straight line being formed between the first swing arm pivot point (3a) and the linkage member first mounting point (3b), and a second straight line being formed between the second swing arm pivot point (5a) and the linkage member second mounting point (5b), wherein the linkage member first mounting point (3b) and the linkage member second mounting point (5b) are so arranged relative to each other that the sum of an angle α between the linkage axis and a line perpendicular to the first straight line and extending from the linkage member first mounting point and an angle β between the linkage axis and a line perpendicular to the second straight line and extending from the linkage member second mounting point is constant or increasing with increasing ditch angle.