whiffletree

whiffletree (HWIF-uhl-tree, WIF-uhl-tree) - (NE US) a crossbar for a plow or carriage, pivoted in the middle, to which the two traces from a draft animal are fastened.


Better known as a singletree, leader bar, or whippletree, and as you might guess this is a variation on the latter. The purpose is to distribute the forces of the pulling animal(s) evenly. When there are multiple pullers, these can and typically are stacked to continue the distribution:


Thanks, WikiMedia!

---L.