BSI 16/30314605 DC:2016 Edition
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BS EN ISO 5459. Geometrical product specifications (GPS). Geometrical tolerancing. Datums and datum systems
Published By | Publication Date | Number of Pages |
BSI | 2016 | 107 |
PDF Catalog
PDF Pages | PDF Title |
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10 | 1 Scope 2 Normative references 3 Terms and definitions |
16 | 4 Symbols |
17 | 5 Role of a datum system |
18 | 6 General concepts |
21 | 7 Graphical language 7.1 General 7.2 Indication of datum features 7.2.1 Datum feature indicator |
22 | 7.2.2 Datum feature identifier 7.2.3 Datum targets 7.2.3.1 General 7.2.3.2 Datum target frame |
23 | 7.2.3.3 Datum target symbol |
24 | 7.2.3.4 Leader line |
25 | 7.2.4 Contacting features |
26 | 7.3 Specification of datums and datum systems 7.4 Indication and meaning of rules 7.4.1 General |
27 | 7.4.2 Rules (potential new clause 8) 7.4.2.1 Rule 1 — Datum features (established from a single feature) |
29 | 7.4.2.2 Rule 2 — Datum features established from a complete feature 7.4.2.3 Rule 3 — Datum features established from a non-complete feature defined by one or more datum targets |
36 | 7.4.2.4 Rule 4 — Datum system |
37 | 7.4.2.5 Rule 5 — Indication of a single or common datum in a datum indicator of a datum section |
38 | 7.4.2.6 Rules 6 for associated features 7.4.2.6.1 General The associated feature is established from the datum feature after filtration, by association of an ideal feature (associated feature) with a non-ideal feature (datum feature). The association criteria combines an objective function and constraint (material constraint, size, orientation, location) The association is defined by several properties: |
39 | This standard defines default objective functions and default filtration criteria. It is possible to change them for an individual specification or globally for a drawing, by defining special operators (see 7.5). 7.4.2.6.2 Rule 6.a: associated feature type |
40 | 7.4.2.6.3 Rule 6.b: dimension of an associated feature |
41 | 7.4.2.6.4 Rule 6.c: material constraints for associated feature 7.4.2.6.5 Rule 6.d: constraint between associated features in a common datum |
42 | 7.4.2.6.6 Rule 6.e: constraint between associated features in a datum system When a single datum or a common datum is indicated as a primary datum (see examples 1 to 4), then no additional constraint in orientation shall be taken into account in the association. When a single datum or a common datum is indicated as a secondary datum (see examples 2 and 3), then rules 6.a, 6.b and 6.c shall be considered with additional constraints to establish the secondary datum from associated feature(s): When a single datum or a common datum is indicated as a tertiary datum (see example 4), then rule 6.a, 6.b and 6.c shall be considered with additional constraints: |
46 | 7.4.2.7 Rule 7 — Locked or released degrees of freedom for the members of its datum system |
48 | 7.4.2.8 Rule 8 — Special indications for common datum |
49 | 7.4.2.9 Rule 9 — Indications of situation feature on the technical product documentation |
50 | 7.4.2.10 Rule 10 — Degrees of freedom indication in relation with a datum system 7.4.2.11 Rule 11 — Application of modifiers in a datum indicator |
52 | 7.5 Datum section (potential new clause 9) 7.5.1 General 7.5.2 ISO default specification operator for single or common datum 7.5.3 Individual specification operator for single or common datum |
53 | 7.5.4 Datum filtration specification elements |
54 | 7.5.5 Datum association specification elements |
55 | 7.5.6 Drawing-specific default for datum |
56 | Annex A (normative) Association for datums A.1 Basic concepts |
57 | A.2 Association methods A.2.1 General |
59 | A.2.2 Association for single datums A.2.2.1 Association for single datums without the [CF] modifier |
60 | A.2.2.2 Association for single datums with the modifier [CF] A.2.3 Association for common datums |
62 | A.2.4 Association for datum systems |
63 | Annex B (informative) Invariance classes |
65 | Annex C (informative) Indication and meaning of datum systems for some examples C.1 Examples of datum systems constituted by one single datum C.1.1 Plane |
66 | C.1.2 Cylinder |
67 | C.1.3 Cone |
68 | C.1.4 Sphere |
69 | C.1.5 Particular situation feature |
70 | C.1.6 Obvious situation feature |
71 | C.1.7 Only one situation feature needed |
72 | C.1.8 Complex surface |
73 | C.1.9 Intersecting planes |
74 | C.1.10 Two parallel opposite planes (defined as a feature of size) |
75 | C.1.11 Three datum targets on a plane |
76 | C.2 Examples of datum systems constituted by one common datum C.2.1 Two coplanar planes |
77 | C.2.2 Two coaxial cylinders |
78 | C.2.3 Plane and cylinder perpendicular to each other |
79 | C.2.4 Two parallel cylinders |
80 | C.2.5 Pattern of five cylinders |
81 | C.2.6 Two parallel planes |
82 | C.3 Examples of datum systems constituted by more than one single datum C.3.1 Three perpendicular planes |
84 | C.3.2 Perpendicular plane and cylinder |
86 | Annex D (normative) Associated feature established from a thread or a gear D.1 General |
87 | D.2 Indication for a thread |
88 | D.3 Indication for a gear |
92 | Annex E (informative) Examples of a datum system or a common datum established with contacting features E.1 Example 1 |
93 | E.2 Example 2 |
94 | E.3 Example 3 |
95 | E.4 Example 4 |
96 | E.5 Example 5 — Example for a “three jaw chuck” |
97 | Annex F (informative) Filter symbols and attached nesting index |
98 | Annex G (informative) Some basic examples of datum G.1 General G.2 Associated plane used to establish a datum |
100 | G.3 Associated circle and cylinder used to establish a datum |
104 | Annex H (normative) Relations and dimensions of graphical symbols |
105 | Annex I (informative) Former practice |
106 | Annex J (informative) Relationship to the GPS matrix model J.1 General J.2 Information about this International Standard and its use J.3 Position in the GPS matrix model J.4 Related International Standards |