US Patent 9175508 Metal door

A metal door comprising first and second side frames or stiles and upper and lower frames or rails which are joined together. Each of the frames includes front and rear panels which are spaced apart and which are secured together by means of insulating panel connectors. The space between the panel connectors in each of the frames is filled with an insulating foam material. The panel connectors are also comprised of an insulating material such as wood, fiberglass, plastic or other insulative material.