BRITISH STANDARD AUTOMOBILE SERIES BS AU 28 1964 (Supersedes S M M T Standard No 63) Specification for Towing jaw for use between trailers of 5–35 tons gross weight and towing vehicle UDC 629 11 013 5[.]
Li cen sed Copy: Lon d on Sou th Ban k U n i versi ty, Lon d on Sou th Ban k U n i versi ty, Sat Dec 09 01 : 52: 38 G M T+00: 00 2006, U n trol l ed Copy, (c) BSI BRITISH STANDARD AUTOMOBILE SERIES Specification for Towing jaw for use between trailers of 5–35 tons gross weight and towing vehicle UD C 62 1 : 62 1 BS AU 28:1964 (Supersedes S M M T Standard No 63) Li cen sed Copy: Lon d on Sou th Ban k U n i versi ty, Lon d on Sou th Ban k U n i versi ty, Sat Dec 09 01 : 52: 38 G M T+00: 00 2006, U n trol l ed Copy, (c) BSI BS AU 28:1964 This Britis h S tandard, having b een ap p roved b y the Automob ile I ndus try S tandards C ommittee and endors ed b y the C hairman of the E ngineering D ivis ional C ouncil, was p ub lis hed under the authority of the General C ouncil of the Amendments issued since publication Ins titution on June 64 © BS I - 0 The following BS I reference relates to the work on this s tandard: C om mittee reference AUE /- ISBN 580 34551 Amd No D ate C omments Li cen sed Copy: Lon d on Sou th Ban k U n i versi ty, Lon d on Sou th Ban k U n i versi ty, Sat Dec 09 01 : 52: 38 G M T+00: 00 2006, U n trol l ed Copy, (c) BSI © BSI 02 - 000 Scope 1 BS AU 28:1964 Materials Contents D imensions Page D esign 1 ii Marking Mounting Foreword i Li cen sed Copy: Lon d on Sou th Ban k U n i versi ty, Lon d on Sou th Ban k U n i versi ty, Sat Dec 09 01 : 52: 38 G M T+00: 00 2006, U n trol l ed Copy, (c) BSI BS AU 8: 964 Fore word This British Standard which is published under the authority of the Automobile Industry Standards Committee of the BSI, is based upon data- sheet SMMT 63: 957 of the Society of Motor Manufacturers and Traders Ltd The requirements of this standard, which relate only to vehicles used on the public highways, are intended to ensure the maximum degree of interchangeability between commercial and Government department and Services standards Towing j aws may be forged (as shown in Figure) or cast The material specifications are for the minimum qualities acceptable, and not exclude the use of other materials provided that these are at least equal in quality so that road safety is not impaired This standard should be used in conj unction with BS AU 29 1) The j aw has been designed to accommodate a drawbar eye of in internal diameter and /8 in stock The standard applies to connections to trailers of 5–35 tons gross weight The specification for a towing j aw for connections to trailers of 5–1 tons gross weight is given in BS AU 26 NOTE 2) , and for trailers of 2–5 tons gross in BS AU 24 3) If it is required to convert the figures in this standard from British units into metric units it is recommended that the conversion factors and tables contained in BS 350, “Conversion tables ”, be used Attention engineering drawings ” is drawn to BS 2856, “ Precise factors and conversion of inch and metric sizes on A British Standard does not purport to include all the necessary provisions of a contract Users of British Standards are responsible for their correct application C omp liance with a British S tand ard d oe s no t of itse lf confe r immunity from le gal ob ligatio ns S ummary of p age s This document comprises a front cover, an inside front cover, pages i and ii, pages and 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 AU 29, “Drawbar eyes and forecarriage pins for connection between trailers of – 35 tons gross weight and towing vehicle” 2) 3) ii BS AU 26, “Towing BS AU 24, “Towing jaw for use between trailers of – tons gross weight and towing vehicle ” connections for trailers of – tons gross weight ” © BSI 02- 2000 Li cen sed Copy: Lon d on Sou th Ban k U n i versi ty, Lon d on Sou th Ban k U n i versi ty, Sat Dec 09 01 : 52: 38 G M T+00: 00 2006, U n trol l ed Copy, (c) BSI BS AU 28:1964 Scope Design This British Standard specifies the basic An efficient safety locking device shall be provided dimensions and quality of materials for a towing j aw as indicated in the Figure to prevent accidental and its mountings, for use in connection between a extraction of the towing pin from the j aw towing vehicle and a trailer of 5–35 tons gross The j aw shall be so designed that a bar /4 in weight diameter may be passed freely between the pin and The gross weight refers to gross laden train weights where more than one trailer is drawn Materials 5) BS 592A 4) En 3A for the forged j aw, or for the cast j aw, both materials to be in their normalized condition diameter, at in × /4 in in centres This renders it interchangeable in mounting with hooks specified in BS AU 25 6) and BS AU 27 7) , and with certain Government department and Services standard The towing pin shall be made from a material of quality not less than BS 970 4) En 6S Dimensions Dimensions shall be as shown in the Figure The ringed dimensions are essential for interchangeability, other dimensions apply to the forged j aw and are for guidance only NOTE Mounting The j aw shall be mounted with four bolts, The j aw shall be made from a material of quality not less than BS 970 the inside face of the j aw (see Figure) The dimensions specified for the forged j aws 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 this standard, connecting the coupling to the towing vehicle shall have a similar strength hooks Bolts and nuts shall comply with: i) BS 083, ii) BS 768, threaded BSF, code symbol R, or 8) threaded UNF, code symbol R9) 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 nut and split pin Marking The following wording, in clear lettering /8 in high, raised or impressed, shall be marked on each towing j aw: “TO TOW 35 TONS GROSS” on one side, and on the other side BS AU 28” 4) BS 970, “Wrought steels in the form of bars, billets and forgings, up to in ruling section, for automobile and general engineering purposes En series” 5) BS 592, (included in BS 31 00) “Carbon steel castings for general engineering purposes ” 6) BS AU 25, “Towing hook for use between trailers of 5–1 tons gross weight and towing vehicle ” 7) BS AU 27, “Towing hook for use between trailers of 5–35 tons gross weight and towing vehicle ” 8) BS 083, “Precision hexagon bolts, screws and nuts ” 9) BS 768, “Unified precision hexagon bolts, screws and nuts (UNC and UNF thread normal series)” © BSI 02- 2000 Li cen sed Copy: Lon d on Sou th Ban k U n i versi ty, Lon d on Sou th Ban k U n i versi ty, Sat Dec 09 01 : 52: 38 G M T+00: 00 2006, U n trol l ed Copy, (c) BSI BS AU 28:1964 © BSI 02 - 000 Li cen sed Copy: Lon d on Sou th Ban k U n i versi ty, Lon d on Sou th Ban k U n i versi ty, Sat Dec 09 01 : 52: 38 G M T+00: 00 2006, U n trol l ed Copy, (c) BSI blank Li cen 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