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1、BRITISH STANDARD BS 7961:2004 Specification for a device for measuring the static vertical mass (noseweight) at the coupling point of a towed vehicle ICS 17.060; 43.040.70; 43.100 ? Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:01:01 GMT+00:00 2006, Uncontr
2、olled Copy, (c) BSI BS 7961:2004 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 27 January 2004 BSI 27 January 2004 The following BSI references relate to the work on this British Standard: Committee reference AUE/8 Draft for comment 00/7049
3、97 DC ISBN 0 580 43114 2 Committees responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee AUE/8, Undergear for caravans and light trailers, upon which the following bodies were represented: Camping and Caravanning Club Limited Caravan Clu
4、b Consumer Policy Committee of BSI DfT Central Transport Group National Caravan Council Limited National Trailer and Towing Association Limited Society of Motor Manufacturers and Traders Limited Trailer and Towing Advisory Service Amendments issued since publication Amd. No.DateComments Licensed Cop
5、y: London South Bank University, London South Bank University, Fri Dec 08 11:01:01 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7961:2004 BSI 27 January 2004 i Contents Page Committees responsibleInside front cover Forewordii 1Scope1 2Terms and definitions1 3The noseweight gauge1 4Test for the dete
6、rmination of durability4 5Test for the determination of overload4 6Test for the determination of accuracy5 Bibliography7 Figure 1 Coupling3 Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:01:01 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7961:2004 ii BSI 27
7、 January 2004 Foreword This British Standard has been prepared by AUE/8, Undergear for caravans and light trailers. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not
8、of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 7 and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued. Licensed Copy: London South
9、 Bank University, London South Bank University, Fri Dec 08 11:01:01 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7961:2004 BSI 27 January 2004 1 1 Scope This British Standard specifies requirements for devices intended to measure the static vertical mass of towed vehicles. Such devices are commonly
10、 known as “noseweight gauges”. This British Standard only applies to all towed vehicles up to 3 500 kg maximum technical permissible laden mass. NOTENormally such towed vehicles are fitted with a 50 mm ball coupling device but the manufacturer of a noseweight gauge may also specify its suitability f
11、or use with other coupling devices. 2 Terms and definitions For the purposes of this British Standard, the following terms and definitions apply. 2.1 ball coupling system mechanical coupling system designed to connect towing vehicles and towed vehicles by means of a coupling ball 2.2 coupling head m
12、echanical device on the drawbar or overrun device of towed vehicles for connection to a coupling ball 2.3 noseweight static vertical mass (“S” value in kg) exerted on the towing vehicle by the towed vehicle at the coupling point NOTEStatic vertical mass is commonly referred to as the S value in the
13、UK and Europe. See Directive 94/20/EEC 1 and UNECE Regulation No. 55 2 for further information. 2.4 towing vehicle mechanically propelled vehicle used for towing a towed vehicle 2.5 towed vehicle vehicle without any means of self-propulsion to be towed by a towing vehicle (e.g. caravan, horse-box, e
14、tc.) 3 The noseweight gauge 3.1 Range The noseweight gauge shall be capable of measuring from 20 kg to at least 100 kg. The noseweight gauge shall be capable of measuring in increments not greater than 5 kg and in the case of an analogue device the minimum scale separation for a 5 kg increment shall
15、 not be less than 5 mm. NOTEThe scale and marked numerical values should be clear and easy to read. Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:01:01 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7961:2004 2 BSI 27 January 2004 3.2 Performance NOTEThe sam
16、e noseweight gauge should be used in performing each of the following three tests. If the noseweight gauge fails at any stage, then no further testing should be carried out. 3.2.1 Durability When tested in accordance with Clause 4, the noseweight gauge shall be able to complete 1 000 test cycles and
17、 continue to meet the accuracy requirements of 3.2.3. 3.2.2 Overload testing After being tested in accordance with Clause 4, the noseweight gauge shall be able to withstand twice the maximum load specified by the device manufacturer, for a period of 30 s, without permanent damage when tested in acco
18、rdance with Clause 5. After removal of the load, the noseweight gauge shall show no deformation. 3.2.3 Accuracy Having undergone the tests described in Clause 4 and Clause 5, the noseweight gauge shall be accurate to within 5 kg or 10 % of the specified mass, whichever is least. 3.3 Operating height
19、 range The operating height range of the noseweight gauge shall be as specified in the manufacturers user instructions. 3.4 Finish All surfaces of the noseweight gauge shall be smooth and free from any burrs or sharp edges that could cause injury. 3.5 Markings All noseweight gauges shall be permanen
20、tly and legibly marked with the following information: a) the weight range, kg to kg; b) the operating height range mm to mm to the centre of rotation of the coupling device in relation to the ground see Figure 1a) and Figure 1b); c) the number and date of this British Standard, i.e. BS 7961:2004; d
21、) the manufacturers name or trade mark; e) reference to the user instructions (see 3.6). 3.6 User instructions Each noseweight gauge shall be supplied with user instructions that shall contain at least the following information: a) detailed instructions for use; b) recommendations for safe operation
22、 of the device; c) recommendations for maintenance, storage and re-calibration. The instructions shall include the following statement: “When assessing/adjusting the noseweight of the towed vehicle, the limiting noseweights that individual components are able to sustain should be taken into account
23、as well as those that the towed vehicle can sustain. The following components should all have limits of noseweight specified by the manufacturer, and any other limiting factors should also be considered in the assessment/adjustment of the noseweight of the towed vehicle: a) towing vehicle; b) vehicl
24、e mounted towing device (tow bar); c) towed vehicle mounted towing device (coupling assembly); d) towed vehicle drawbar assembly; e) towed vehicle.” Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:01:01 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7961:2004
25、BSI 27 January 2004 3 Key 1 is the vehicle 2 is the center of rotation 3 is the range of operating height from the centre of rotation to the ground a) Coupling ball Key 1 is the vehicle 2 is the center of rotation 3 is the towed vehicle drawbar 4 is the range of operating height from the centre of r
26、otation to the ground b) Coupling jaw and eye Figure 1 Coupling 1 2 3 1 3 2 4 Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:01:01 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7961:2004 4 BSI 27 January 2004 4 Test for the determination of durability 4.1 Pr
27、inciple The noseweight is operated in cycles from an S value of zero to the maximum specified for the noseweight gauge under test and back again to an S value of zero. The gauges ability to successfully complete a given number of test cycles is taken as a measure of its durability. 4.2 Apparatus 4.2
28、.1 test rig, with a suitable means of force application so that it is not subjected to any additional forces or moments apart from an S value commensurate with the maximum specified for the noseweight gauge under test. 4.2.2 noseweight gauge. 4.3 Initial inspection of the noseweight gauge Prior to t
29、he start of the test check the noseweight gauge for any deformation. 4.4 Procedure Set up the test rig to apply the specified test forces to the noseweight gauge. Perform the load/unload cycle from an S value of zero to the maximum specified for the noseweight gauge under test and back again to an S
30、 value of zero. Repeat the load/unload cycle at a frequency of not greater than 1 Hz until a minimum of 1 000 cycles have been completed. 4.5 Final inspection of the noseweight gauge Check the noseweight for any deformation. If there is no obvious deformation, undertake the overload test described i
31、n Clause 5. 4.6 Expression of results Record the number of test cycles completed without failure. If 1 000 or more test cycles have been successfully completed, record a “PASS”. If less than 1 000 test cycles have been completed, record a “FAIL”. 4.7 Test report The test report shall include the fol
32、lowing: a) reference to this British standard, i.e. BS 7961:2004; b) the test result recorded in accordance with 4.6; c) the date of the test; d) where the test took place. 5 Test for the determination of overload 5.1 Principle Following testing in accordance with Clause 4, the noseweight gauge is l
33、oaded to twice the maximum specified S value for the noseweight under test for a measured time and inspected for signs of deformation and damage. The gauges ability to successfully complete a given number of test cycles without deformation is taken as a measure of its durability. Licensed Copy: Lond
34、on South Bank University, London South Bank University, Fri Dec 08 11:01:01 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7961:2004 BSI 27 January 2004 5 5.2 Apparatus 5.2.1 test rig, with a suitable means of force application so that it is not subjected to any additional forces or moments apart fro
35、m an S value commensurate with the maximum specified for the noseweight gauge under test. 5.2.2 noseweight gauge. 5.3 Initial inspection of the noseweight gauge Prior to the start of the test, check the noseweight gauge for any deformation. If there is any deformation, do not proceed with the test.
36、5.4 Procedure Set up the test rig to apply the test force to the noseweight gauge. Maintain twice the maximum specified S value for the noseweight under test for a period of 30 s and then release. 5.5 Final inspection of the noseweight gauge Check the noseweight for any deformation. If there is no o
37、bvious deformation, undertake the accuracy test described in Clause 6. 5.6 Expression of results Record any visible changes shown between the initial and final inspections of the noseweight gauge. If there is no obvious deformation, record a “PASS”. If there is obvious deformation, record a “FAIL”.
38、5.7 Test report The test report shall include: a) reference to this British Standard, i.e. BS 7961:2004; b) the result of the test in accordance with 5.6; c) the date of the test; d) where the test took place. 6 Test for the determination of accuracy 6.1 Principle After the noseweight gauge has been
39、 successfully tested in accordance with the tests described in Clause 4 and Clause 5, test forces of one-third, two-thirds and the maximum specified S value for the noseweight gauge under test are applied and the results indicated by the noseweight gauge are analysed for conformance with 3.2.3. 6.2
40、Apparatus 6.2.1 test rig, with a suitable means of force application so that it is not subjected to any additional forces or moments apart from an S value commensurate with the maximum specified for the noseweight gauge under test. 6.2.2 noseweight gauge. 6.3 Initial inspection of the noseweight gau
41、ge Prior to the start of the test, check the noseweight gauge for any deformation. If there is any deformation, do not proceed with the test. 6.4 Procedure Apply each force to the noseweight gauge. Note the reading of each force. Licensed Copy: London South Bank University, London South Bank Univers
42、ity, Fri Dec 08 11:01:01 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7961:2004 6 BSI 27 January 2004 6.5 Final inspection of the noseweight gauge Check the noseweight for any deformation. 6.6 Expression of results Record the weight of each test force and the reading taken from the noseweight gauge
43、. Calculate the variance between each applied force and the indicated reading taken from the noseweight gauge. 6.7 Test report The test report shall include: a) reference to this British Standard, i.e. BS 7961:2004; b) the result of the test in accordance with 6.4; c) the date of the test; d) where
44、the test took place. Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:01:01 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7961:2004 BSI 27 January 2004 7 Bibliography 1 Directive 94/20/EC of the European Parliament and of the Council of 30 May 1994 relating to
45、 the mechanical coupling devices of motor vehicles and their trailers and their attachment to those vehicles. Official Journal L 195, 29/07/1994, p. 00010060. 2 UNECE (Economic Commission for Europe of the United Nations) Regulation No. 55, Agreement Concerning the Adoption of Uniform Conditions of
46、Approval and Reciprocal Recognition of Approval for Motor Vehicle Equipment and Parts. Geneva, 20 March 1958. Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:01:01 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7961:2004 BSI 389 Chiswick High Road London W4 4A
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