ISO 18207:2006 道路車両—最大3.5 tのトレーラー—疲労試験後のカップリングボール用の溶接牽引ブラケットの制御 | ページ 2

Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established 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. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.

The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote.

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights.

ISO 18207 was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 4, Caravans and light trailers.

Introduction

Almost all of the towing brackets available on the European market are made of steel parts constructed by mechanical welding using semi-automatic machines. This process of welding is used for its good adaptation to mass production which generates welding defects that do not necessarily lead to cracking or fatigue ruptures during the test.

The uniqueness of control after fatigue testing thus leads to the detection of indications ¹ of which the origin, determining the outcome of the control, cannot be deduced with certainty:

• Welding defects which have not developed after the imposed 2×, 10⁶ cycles, thus deduced without seriousness;
• Fatigue cracks initiated during the test or defects of welding having started a process of cracking, constituting a crippling deterioration.

In the absence of data on the initial state of the product before fatigue test, the discrimination of these two types of indications can require long and expensive work (appropriate cutting up of the coupling for micrographic and/or microfractographic examination under a scanning electron microscope), which is not possible in a systematic way for economic reasons within the framework of these tests.

Hence, the requirement for a method of non-destructive tests acceptable in all cases without having to resort to these long and expensive examinations.

1 Scope

This International Standard defines a simplified and reliable check procedure of the mechanical coupling devices between light trailers, and towing vehicles, covered by ISO 3853 and European regulation (94/20/CE), which specify a dynamic test of mechanical resistance at the conclusion of which these devices should present neither fractures, splits, cracks, nor visible external deteriorations caused by the test.

This International Standard is applicable to all the components of the mechanical coupling devices whose failure can cause the fracture of the attachment, manufactured out of steel, forged steel or cast steel (i.e. generally in ferromagnetic materials).

In the case of use of other materials, the manufacturer will check their compatibility with the methods of non-destructive testing.

2 Normative references

The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

Bibliography