Typebar

A typebar is an 'arm' inside a typewriter with a characters on the end of it. There are generally two characters per typebar; one which will be printed if the key is struck by itself, the other of which will be printed if the key is struck while the shift key is depressed. The typewriter will jam when two or more typebars are depressed simultaneously. Such jamming led to the creation of the QWERTY keyboard.