ISO INTERNATIONAL STANDARD 7643 Second edition 1991-07-15 Caravans and light trailers --. Trailers of categories O, and O, with overrun brakes Linear bench test methods for brake controls Caravanes et remorques legeres -- Remorques des categories O et O2 a freins a inertie -- Methodes d'essai des dispositifs de commande de freinage sur barc lineaire Reference number ISO 7643:1991(E) Not for Resale ISO 7643:1991(E) Foreword IsO (the Internationai 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 IsoO 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 International organizations, govern- committee. mental 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. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an Inter- national Standard requires approval by at least 75 % of the member bodies casting a vote. International Standard isO 7643 was prepared by Technical Committee ISO/TC 22, Road vehicles, Sub-Committee SC 4, Caravans and light trailers. This second edition cancels and replaces the first edition (isO 7643:1983), certain values of which have been altered and references updated. C ISO 1991 All rights reserved. No part of this publicatlon may be reproduced or utilized in any. form permission in writing from the publisher. Internatlonal Organization for Standardization Case Postale 56· CH-1211 Geneve 20 · Switzerland Printed in Switzerland without license from IHS Not for Resale ISO 7643:1991(E) INTERNATIONAL STANDARD Caravans and light trailers --. Trailers of categories O, and O, with overrun brakes --- Linear bench test methods for brake controls ISO/TR 4114:1979, Road vehicles Caravans and Scope light trailers -- Static load on ball couplings This International Standard specifies test methods for type approval testing of controls on trailers for overrun brakes.1) The test method is based on the requirements of ECE Regulation No. 13 of the United Nations, Uni- Symbols and definitions (see figure 1) 3 form provisions concerning the approval of vehicles withregard to braking.lt istherefore recommended G'A is the trailer total weight capable of being that reference should be made to this Regulationto braked by the control device, as declared assist with the use of this International Standard. by the manufacturer; G'A These test methods apply to the type approval of is the minimum total weight capable of categories O and O,2) trailers with inertia brakes being braked; by testing the control devices on a linear test bench. G'A2 is the maximum total weight capable of being braked; s is the travel of the control, in millimetres; s" is the effective travel of the control in millimetres; S。 is the loss of travel, applicable to multi- Normative reference axle trailers only, i.e. travel in millimetres of coupling head when this is actuated to move from 300 mm above to 300 mm be- The foilowing standard contains provisions which, low the horizontal, the transmission re- through reference in this text, constitute provisions maining stationary; of this International Standard.At the time of publi- cation, the edition indicated was valid. All standards S"! is the spare travel of the master cylinder, are subject to revision, and parties to agreements measured in millimetres at the coupling based on this International Standard are encour- head; aged to investigate the possibility of applying the most recent edition of the standard indicated below. is the reduction ratio between the travel iH. Members of IEc and 1so maintain registers of cur- of the couping head and the lev