Origin of doubletree
Examples from the Web for doubletree
The doubletree served as a lever on which to mount two singletrees.
Three horses drew the plow, which has three singletrees and one doubletree.
Across the doubletree behind them hung the limp form of their driver, a great, gaping wound in his head.Castle Craneycrow|George Barr McCutcheon
The arms of the tongue are connected by a crossbar, to which the doubletree is pivoted by a hammer bolt.