ISO 翻译作业.pdf

21 _______________________ Differences between ISO Standards and other Standards 21.1 ASME Y14.5M – 1994, ANSI B89.3.1 In the following the terminology of ASME Y14.5 is used (see Table 21.3). 21.1.1 Symbols The National Standard of the United States of America ASME Y14.5M–1994 specifies in addition to or deviating from ISO 1101 the symbols and drawing indications shown in Tables 21.1 and 21.2. Table 21.1 Symbols according to ASME Y14.5M *Not specified in ASME Y14.5M but usual in US practice. 327 328 Geometrical Dimensioning and Tolerancing for Design, Manufacturing The symbol “CZ” is not standardized according to ASME Y14.5. When it is used in drawings referenced to ASME Y14.5 the reference to ISO 1101 should also be intro- duced into the drawing title block, together with the remark: In cases of contradiction ASME Y14.5 applies. 21.1.2 Rules ASME Y14.5M deviates in some rules from the specifications given in the ISO Standards. ASME Y14.5M specifies the following rules: Rule #1: Where only a tolerance of size is specified, the limits of size of an individual feature prescribe the extent to which variations in its geometrical form, as well as size, are allowed. In other words, for individual features of size the envelope requirement applies with- out drawing indication. Exceptions are as follows: ● stock materials (such as bars, sheets, tubing, structural shapes) for which straight- ness, flatness or other geometrical tolerances are standardized and which remain in the “as-furnished” condition on the finished part; Table 21.2 Drawing indications according to ASME Y14.5M Differences between ISO standards and other standards 329 ● (non-rigid) parts subject to free state variation in the unrestrained condition (see 12); ● features with a straightness tolerance to the axis or a flatness tolerance to the m