Horse drawn carriage two main different types of swingle tre

The two main types are the solid bar swivelling on a central pin and the flexible rope type that moves on a system of pulleys. The swingle tree fulfils an important function, when the horse is pulling the carriage via the traces and breast collar there is a horizontal seesawing movement caused by the shoulder action of the horse if you did not have a swingle tree the breast collar would rub the shoulder of the horse causing discomfort and harm.