ISO 10303-214:2010(E)
4.2.231 General_classification
A General_classification is a classification of an object which characterizes all objects of the same kind; such a classification is independent from the application of the classified object.
EXAMPLE A fastener with subclasses, such as fastener with 2 or 3 fixture holes, a bracket with subclasses, e.g., with 90 or 100 degrees bending angle, or screws with subclasses such as metal screws or machine screws are examples for General_classification.
EXAMPLE For facilitating an effective part retrieval for slotted screws, several General_classification objects may be defined to classify screws:
- A General_classification *1 with description 'slotted screws' and three subclasses with the descriptions *2: 'slotted cheese head screws - product grade A', *3: 'slotted pan head screws - product grade A', and *4: 'slotted countersunk flat head screws - product grade A'.
- Each of the General_classification objects is based on a Classification_system that further defines where the definition of the General_classification comes from. For General_classification *1 this is a company internal Classification_system for 'screw classes'. For the other General_classification objects these are ISO standardized Classification_system objects, namely for *2 'ISO 1207' [8], for *3 'ISO 1580' [9], and for *4 'ISO 2010' [10].
- The General_classification objects may be defined as well in an ISO 13584 compliant library (PLIB). In this case, General_classification *1 references as a classification source an External_library_reference that has an id corresponding to the class_BSU, i. e. a world wide unique identification of that class as defined according to ISO 13584-42. In another case, the source of a General_classification may only be available as a document in paper form. In this case, General_classification *4 references a Physical_document with document id 'DIN EN ISO 2010' and description 'slotted countersunk flat head screws - product grade A'.
- The General_classification objects may be characterized further by Classification_attribute objects. According to ISO 1207, the General_classification *2 has the attributes *11 with id 'd' and description 'thread', *12 with id 'l' and description 'nominal length', *13 with id 'mechanical properties' and description 'property class', etc. The possible values 'M1.6', 'M2', ..., 'M10' for Classification_attribute *11 may be defined as Property_value_representation objects in a set of the attribute allowed_value. The according specification is given as 'value_name' of the AO Property_value referenced by 'specified_value'. The Property_value_representation refer as their definition to a General_property with the 'property_type' 'nominal metric thread diameter'.
- To identify the designation 'Cheese head screw ISO 1207 - M5 x 20 x 4.8', a subclass of General_classification *2 is defined with the same description and classification source and the description 'slotted cheese head screws ISO 1207 -M5 x 20 x 4.8' but with the values for Classification_attribute corresponding to *11 restricted to 'M5' only, i.e., to get just the M5 screws, corresponding to *12 restricted to value '20' only, and corresponding to *13 restricted to value '4.8' only (for steel according to ISO 898-1 [7]).
The data associated with a General_classification are the following:
- classification_source;
- description;
- id;
- used_classification_system;
- version_id.
4.2.231.1 classification_source
The classification_source specifies the External_library_reference or the Plib_class_reference that contains the specification of the General_classification.
See general_classification to external_library_reference and general_classification to plib_class_reference for the application assertions.
The classification_source need not be specified for a particular General_classification.
If present, there shall be exactly one object that defines the classification_source for a General_classification.
4.2.231.2 description
The description specifies additional information about the General_classification.
EXAMPLE 'fastener with 2 fixture holes' or 'bracket with 90 degree bending angle' are examples for description.
See general_classification to multi_language_string for the application assertion.
The description need not be specified for a particular General_classification.
If present, there shall be exactly one object that defines the description for a General_classification.
4.2.231.3 id
The id specifies the identifier of the General_classification.
4.2.231.4 used_classification_system
The used_classification_system specifies the Classification_system that contains the information about the definition of the classification and how to interpret the name of the General_classification.
See general_classification to classification_system for the application assertion.
The used_classification_system need not be specified for a particular General_classification.
4.2.231.5 version_id
The version_id specifies the identification of a particular version of the General_classification.
The version_id need not be specified for a particular General_classification.
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