A Carolina balance gate is an archaic type of balance gate that was once popular (pre-1900s) in North Carolina.
A balance gate is a gate which, instead of being hung on two or more hinges, is built to descend from a crossbeam that rests on top of the gatepost; this crossbeam rotates using the gatepost as an axis. On one side of the post the gate hangs down from the crossbeam, and on the other side there is a counterweight to balance the gate. In New England the counterweight was usually made using a large rock or bucket of stones, and thus the projecting arm of the crossbeam counterbalancing the gate could be quite short.
In a Carolina balance gate, there was no proper counterweight, and balance was provided by having a much longer arm of the crossbeam -- constructed from a hefty beam of wood -- project out on the side away from the gate. This long beam swung into place over top of the fence, and when the gate was closed it was safely out of the way. When the gate was open it swung out into the yard, hopefully not beaning or kneecapping anyone in the process.
While these gates were simple and easy to make, the long swinging balance arm was a bit of a safety hazard, and the prefabricated options provided by modern hardware stores have made homemade balance gates a rare sight. If one does want a balance gate, the availability of cheap cement -- and the rising cost of heavy wood beams -- makes the New England style of gate more economical.