GB1303804A - - Google Patents

Abstract

1303804 Toothed gearing NATIONAL RESEARCH DEVELOPMENT CORP 2 Feb 1970 [5 Feb 1969] 6186/69 Heading F2Q A gear-wheel, chain wheel, or ratchet wheel comprises tooth units, each having a tooth section 5 and a root section 6, mounted on a hub 4 so that the root sections, either alone or with intermediate wedges, form a continuous annulus. The radial extent of the root sections is at least twice the tooth height. Each tooth unit may comprise a single tooth, as shown, or several teeth, and has a bifurcated root section which sits astride a circumferential rib 12 on the hub 4. Locking rings 19, 20 engage slots 13, 14 in the rib 12 and 15, 16 in the root sections 6 to retain the tooth units 1, 2 radially. The rings 19, 20 may be subdivided into short lengths, or may be integral with the rib 12. To locate the tooth units circumferentially, at least one tooth unit 3 is seated in a notch 22 in the outer periphery of the rib 12 and retained radially by axial pins (23, 24), (Fig. 3, not shown), the unit or units 3 being assembled last. Adjacent tooth units may contact one another at surfaces 9, 10 of their root sections, or along the full radial end faces of the roots. In a modification, the root sections each have a central rib which engages in a peripheral groove in the hub, which is split in a plane normal to the axis of rotation, the halves being bolted together to grip the tooth units.