Driving Bit for Harness
Headgear without a bit that uses a nose band to control a horse is called a hackamore, or, in some areas, a bitless bridle. There are many different designs with many different name variations, but all use a nose band that is designed to exert pressure on sensitive areas of the animal's face in order to provide direction and control.
Government Printing Office The Official Gazette of the United States Patent Office (Washington, DC: Government Printing Office, 1895)
Courtesy the private collection of Roy Winkelman