Abstract: A new type of involute gear is presented. The tooth shape of the gear consists of two involute curves, which are linked by a transitional curve and form the ladder shape of the tooth. Such gear is called "the double involute gear with ladder shape of tooth” by the authors. Because of the tooth thickness of the dedendum is larger than that of the common involute gear and the pitches do not contact each other, the beam strength and surface strength of tooth are increased. In addition, the technology, of this kind of gear is much better than that of the W-N gear. The main results about the theory, manufacture and experiments on the bedstand are reported.

Key words: Double involute, Gear, Ladder shape