BS EN ISO 2692 pdf free download

BS EN ISO 2692-2021 pdf free download.Geometrical product specifications [GPS] – Geometrical tolerancing – Maximum material requirement (MMR), I east material requirement (LMR) and reciprocity requirement (RPR).
4.1.4 MMR or LMR applied to several toleranced features
When an MMR or LMR applies to several toleranced features, the symbols CZ or SZ shall always be indicated in the zone section of the tolerance indicator following the sequence order specified in
iso noi.
NOTE See Annex B for former practice.
4.1.5 Simultaneous requirement
A simultaneous requirement can be useful for example for MMR or LMR with same datum indication containing MMR or LMR.
When a simultaneous requirement is needed, the SIM symbol possibly followed by an identification number (SIMI) without a space shall be indicated in the adjacent indication area of each related geometrical specification in accordance with ISO 5458.
The use of the SIM modifier transforms a set of more than one geometrical specification with MMR or LMR into a combined specification. The corresponding MMVC or LMVC are locked together with location and orientation constraints according to the rules ofthis document. The datum system is also constrained to be the same for each specification in the same SIM group.
Figure A.17 shows an example of simultaneous requirement.
4.1.6 MMR or LMR on a datum without MMR or LMR on the toleranced feature
When an MMR or LMR is applied to the datum only (see Figure A.19), then the rules for datum fully apply (see 4.2.2. 4.2.4 and 4.3.2. 4.3.4). In addition, the constraints on the MMVC(s) ofthe datum(s) and the MMVC(s) ofthe toleranced feature(s) stated in rule D [see 4.2.1 d)] or in rule K (see 4.3.1 d)] are replaced with the corresponding constraints applied on the MMVC(s) ofthe datum(s) and the tolerance zone as defined in ISO 1101 and ISO 5459.
4.2 Maximum material requirement (MMR)
4.2.1 MMR for toleranced features with indirect determination ofvirtual size
When the MMR applies to the toleranced feature and the indirect determination of virtual size is selected, it shall be indicated on drawings by the symbol ® placed after the geometrical tolerance of the derived feature of the feature of linear size (toleranced feature) in the tolerance indicator with no size indicated in square brackets.
The MMR for toleranced features with indirect determination ofvirtual size results in four independent requirements:
— a requirement for the upper limit ofthe size [see rules A 1) and A 2)];
— a requirement for the lower limit ofthe size [see rules B 1) and B 2)];
— a requirement for the surface non-violation ofthe MMVC (see rule C);
— a requirement for applying constraints on MMVCs (see rule D).
When the MMR is specified for the toleranced feature with indirect determination ofvirtual size, then the following rules shall be applied for the surface(s) (of the feature of linear size), and the MMVS shall be computed from the size specification and the geometric specification according to the rules of this document.
a) Rule A: The sizes ofthe toleranced feature shall be:
1) equal to or smaller than the MMS, for external features; equal to or larger than the MMS, for internal features.
NOTE 1 This rule can be altered by the indication of RPR, with symbol® after the symbol [see 52 and Figure A.1 b)].
b) Rule B: The sizes ofthe toleranced feature shall be:
1) equal to or larger than the LMS, for external features [see Figures A.2 a), A a), AA a), A4 a), Al a), A.10. A.11 and A.12]
equal to or smaller than the LMS, for internal features [see Figures A.2 b), &3 b), A4 b), A b), Al b), A.1O to A.13, A.16 to A.19].
c) Rule C: The MMVC ofthe toleranced feature shall not be violated by the extracted (integral) feature (see Figures A.2. A.i AA, A Al A.10 to A.19).
NOTE 2 Use of the envelope requirement ® may lead to superfluous constraints, reducing the technical and economic advantage oIMMR, ifthe functional requirement is purely assemblability.
NOTE 3 The indication O(applied to a form specification on a feature of linear size has the same meaning as the envelope requirement() applied to a size.
d) Rule D: The rule applies as follows:
— When the geometrical specification is an orientation or a location relative to a (primary) datum or a datum system, the MMVC of the toleranced feature shall be in theoretically exact orientation or location relative to the datum or the datum system, in accordance with ISO 1101 and ISO 5459 (see 39, Note 2 to entry, and Figures A.3. AA, Afi and Al).
— Moreover, if several toleranced features are controlled by the same tolerance indication with the CZ symbol, the MMVCs shall also be in theoretically exact orientation and location relative to each other (see Figures A.1, AlO. All and A.13).
— lfseveral toleranced features are controlled by the same tolerance indicator with the SZ symbol, then the MMVCs are not constrained to be in theoretically exact orientation nor location relative to each other (see Figure A.18). In both cases (CZ or SZ indication) constraints relative to datums remain.
— Additionally, if the symbol SIM possibly followed by an index number as required by ISO 5458 is indicated, then the MMVCs shall be constrained in orientation and location with the MMVCs of the SIM group.
4.2.2 MMR for related datum features with indirect determination of virtual size
When the MMR applies to the datum feature and the indirect determination of virtual size is selected, it shall be indicated on drawings by the symbol Q!J placed after the datum letter(s) in the tolerance indicator.
The datum letter(s) followed by the symbol ® result in an associated feature with a fixed size defined by the MMVC.
NOTE 1 Virtual conditions of toleranced feature and datum feature are constrained between them in orientation and location. The result is one combined virtual condition.BS EN ISO 2692 pdf download.