1、BRITISH STANDARD AUTOMOBILE SERIES BS AU26:1964 (Supersedes S.M.M.T. Standard No. 62) Incorporating Amendment No.1 Specification for Towing jaw for use between trailers of516tons gross weight and towing vehicle UDC 629.11.013.5:629.11.013.35BSAU26:1964 This BritishStandard, having been approved by t
2、he AutomobileIndustry StandardsCommittee and endorsed by the Chairman oftheEngineering Divisional Council, was published under theauthority of the General Council of the Institution on 15June1964 BSI03-2000 The following BSI reference relates to the work on this standard: Committee reference AUE/- I
3、SBN 0 580 34549 1 Amendments issued since publication Amd. No. Date of issue Comments 72 August1968 Indicated by a sideline in the marginBSAU26:1964 BSI 03-2000 i Contents Page Foreword ii 1 Scope 1 2 Materials 1 3 Dimensions 1 4 Design 1 5 Mounting 1 6 Marking 1BSAU26:1964 ii BSI 03-2000 Foreword T
4、his BritishStandard, which is published under the authority of the Automobile Industry Standards Committee of the BSI, is based upon data-sheet SMMT62:1957 of the Society of Motor Manufacturers and Traders Ltd. The requirements of this standard, which relate only to vehicles used on the public highw
5、ays, are intended to ensure the maximum degree of interchangeability between commercial and Government department and Services standards. Towing jaws may be forged (as shown in Figure) or cast. The material specifications are for the minimum qualities acceptable, and do not exclude the use of other
6、materials provided that these are at least equal in quality so that road safety is not impaired. This standard should be used in conjunction with BS AU29 1) . The jaw has been designed to accommodate a drawbar eye of2in internal diameter and1; in stock, or3 in internal diameter and1C in stock. The s
7、tandard applies to connections to trailers of516tons gross weight. The specification for a towing jaw for connections to trailers of535tons gross weight is given in BS AU28 2) , and for trailers of25tons gross weight in BSAU24 3) . NOTEIf it is required to convert the figures in this standard from B
8、ritish units into metric units it is recommended that the conversion factors and tables contained in BS350, “Conversion factors and tables”, be used. Attention is drawn to BS2856, “Precise conversion of inch and metric sizes on engineering drawings”. A British Standard does not purport to include al
9、l the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andi
10、i, pages1 and 2 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. 1) BS AU29, “Drawbar eyes and forecarriage pins for connection between trailers of535tons gross wei
11、ght and towing vehicle”. 2) BS AU28, “Towing jaw for use between trailers of535tons gross weight and towing vehicle”. 3) BS AU24, “Towing connections for trailers of25tons gross weight”.BSAU26:1964 BSI 03-2000 1 1 Scope This BritishStandard specifies the basic dimensions and quality of materials for
12、 a towing jaw and its mounting, for use in connections between a towing vehicle and a trailer of5 16 tons gross weight. The gross weight refers to gross laden train weights where more than one trailer is drawn. 2 Materials The jaw shall be made from a material of quality not less than BS970 4) . En3
13、A for the forged jaw, or BS592A 5)for the cast jaw, both materials to be in their normalized condition. The towing pin shall be made from a material of quality not less than BS970 4)En8Q. 3 Dimensions Dimensions shall be as shown in the figure. The ringed dimensions are essential for interchangeabil
14、ity, other dimensions apply to the forges jaw and are for guidance only. NOTEThe dimensions specified for the forged jaws have been calculated on the basis of the total yield strength being not less than two thirds of the gross weight being towed. It is necessary that any other parts not covered by
15、this standard, connecting the coupling to the towing vehicle shall have a similar strength. 4 Design An efficient safety locking device shall be provided as indicated in the Figure to prevent accidental extraction of the towing pin from the jaw. The jaw shall be so designed that a bar1 in diameter m
16、ay be passed freely between the pin and the inside faces of the jaw (seeFigure). 5 Mounting The jaw shall be mounted with four bolts, C in diameter, at4 in 4in centres. This renders it interchangeable in mounting with hooks specified in BS AU25 6)and BS AU27, 7)and with certain Government department
17、 and Services standard hooks. Bolts and nuts shall comply with: i) BS1083 8) , threaded BSF, code symbol R, or ii) BS1768 9) , threaded UNF, code symbol R. The nuts shall be secured either by peening the end of the bolt or by fitting a positive locking device such as a safe locking nut or a slotted
18、nut and split pin. 6 Marking The following working, in clear lettering B in high, raised or impressed, shall be marked on each towing hook: “TO TOW16TONS GROSS” on one side, and on the other side “BS AU26”. 4) BS970, “Wrought steels in the form of bars, billets and forgings, up to6 in ruling section
19、, for automobile and general engineering purposes. En series”. 5) BS592, (including BS3100), “Carbon steel castings for general engineering purposes”. 6) BS AU25, “Towing hook for use between trailers of514tons gross weight and towing vehicle”. 7) BS AU27, “Towing hook for use between trailers of5 3
20、5tons gross weight and towing vehicle”. 8) BS1083, “Precision hegagon bolts, screws and nuts”. 9) BS1768, “Unified precision hexagon bolts, screws and nuts (UNC and UNF thread-normal series)”.BSAU26:1964 2 BSI 03-2000blankBS AU26:1964 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInsti
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