2203 NTERNATIONALSTANDARD (TSO) INTERNATIONAL ORGANIZATION FOR STANDARDIZATION·MEKAYHAPOAHA OPTAHH3ALIHA IO CTAHIAPTH3ALIHH·ORGANISATION INTERNATIONALE DE NORMALISATION Technical drawings -- Conventional representation of gears First edition -- 1973-03-15 ISO 2203-1973 (E) UDC 744.4 : 621.83 Ref.No. ISO 2203-1973 (E) Descriptors : drawings, engineering drawings, gears, chain wheels, representation. Price based on 6 pages FOREWORD ISO (the International Organization for Standardization) is a worldwide federation of national standards institutes (isO Member Bodies). The work of developing International Standards is carried out through Iso Technical Committees. Every Member Body interested in a subject for which a Technical Committee has been set up has the right to be represented on that Committee. International organizations, governmental and non-governmental, in liaison with isO, also take part in the work. Draft international Standards adopted by the Technical Committees are circulated to the Member Bodies for approval before their acceptance as International StandardsbytheISOCouncil. InternationalStandardIS02203wasdrawnupbyTechnical Committee ISO/Tc 10, Technical drawings, and circulated to the Member Bodies in January 1971. It has been approved by the Member Bodies of the following countries : Australia Hungary Portugal Austria India Romania Belgium Ireland South Africa, Rep. of Canada Israel Sweden Chile Italy Switzerland Czechoslovakia Japan Turkey Denmark Korea, Dem.P.Rep. of United Kingdom Egypt, Arab Rep. of Korea,Rep.of U.S.A. France Netherlands U.S.S.R. Germany New Zealand Greece Norway No Member Body expressed disapproval of the document. InternationalOrganizationforStandardization,1973 Printed in Switzerland. ISO 2203-1973 (E) INTERNATIONALSTANDARD Technical drawings -- Conventional representation of gears 1 SCOPEANDFIELDOFAPPLICATION This International Standard establishes the conventional representation of the toothed portion of gears including worm gearing and chain wheels. It is applicable to detail drawings and assembly drawings. As a fundamental principle a gear is represented (except in axial section) as a solid part without teeth, but with the addition of the pitch surface in a thin long chain line. NOTE-For uniformity all figures in this international Standard are in first angle projection (Method E). It should be understood that the third angle projection (Method A) could equally well have FIGURE1 been used withoutprejudice to the principles established. 2 DETAIL DRAWINGS (INDIVIDUAL GEARS) 2.1 Contours and edges Represent the contours and the edges of each gear (see Figures 1, 2 and 3), as if they were, in an unsectioned view, a solid gear bounded by the tip surface; in an axial section, a spur gear having two diametrically opposed teeth, represented unsectioned, even in the case of a gear that does not have spur teeth FIGURE2 or that has an odd number of teeth. 2.2 Pitch surface Draw the pitch surface with a thin, long chain line, even in concealed portions and sectional views, and represent it, in a projection normal to the axis, by its pitch circle (external pitch circle in the case of a bevel gear and the median pitch circle in the case of a worm wheel) (see Figures 1, 2 and 3); in a projection parallel to the axis, by its apparent contour, extending the line beyond the gear contour on each side (see Figures 1, 2 and 3). FIGURE3 1