Compared with link constant hangers, main-compensating constant hangers are structural symmetric, having high theoretical constant force. Swing cams are important component of the device, therefore the design of cam curve is the key of constant hangers. Based on the analysis of working principle of constant hangers, a mechanical model of constant hanger is established, and the differential
... [Show full abstract] equation of cam curve is derived by means of coordinate transformation .Meanwhile, spring parameters are determined. Curve equation is resolved and the cam curves are plotted. Then, the influence of spring parameters on cam curves is discussed. Finally, force values acting on the cam and the central rod are calculated according to cam curve. The simulations in this paper can be used to instruct the actual engineering design.