BRITISH STANDARD AUTOMOBILE SERIES BS AU 3 1970 Specification for Clearance dimensions and fifth wheel positions for tractors and semi trailers UDC 629 114 2 013 6 BS AU 3 1970 This British Standard,[.]
BRITISH STANDARD AUTOMOBILE SERIES Specification for Clearance dimensions and fifth wheel positions for tractors and semi-trailers UD C 62 1 BS AU 3:1 970 BS AU : 970 Fore word This British Standard, prepared under the authority of the Automobile Industry Standards Committee of the BSI, was first published in 963 and later revised in 968 to assist interchangeability of tractors and semi- trailers to the weights and dimensions permitted by the Motor Vehicles (Construction and Use) Regulations No 321 : 969 The present revision incorporates additional data for articulated vehicles considered necessary as a result of experience in the use of the standard Trailer manufacturers will note that the application of this standard depends upon the knowledge of the dimensions of the towing vehicles Users will note that the physical interchangeability between the towing vehicle and the semi- trailer does not itself ensure compatibility of load carrying, braking, lighting and overall length It is important that the equipment be so designed that semi- trailers will couple easily and satisfactorily with the towing vehicle, and not slope forward when the fifth wheel is mounted in accordance with the dimensions given in this standard NO TE The values specified in imperial units are to be regarded as the standard The metric units are given as approximate equivalents 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 o mp liance with a British S tand ard doe s not o f itse lf co nfe r immunity fro m le gal ob ligations S ummary o f p age s This document comprises a front cover, an inside front cover, pages i and ii, pages to 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 This British Standard, having been approved by the the inside front cover Automobile Industry Standards Committee, was published under the authority of the Executive Ame ndme nts issue d since p ub lication Board of the Institution on 20 March 970 © BSI 09- 999 The following BSI reference relates to the work on this standard: Committee reference AUE/- IS B N 80 7 Amd No Date Comments BS AU 3:1970 Contents Page Foreword Inside front cover Scope D imensions Articulation Heights Figure — D imensions of towing vehicle with single rear axle and of semi- trailer Figure — Clearance dimensions between towing vehicle and semi- trailer to permit specified articulation Tab le — Preferred dimensions for single axle semi- trailers in articulated vehicles not exceeding tons and tandem axle semi- trailers in articulated vehicles not exceeding tons gross train weight Tab le — Preferred dimensions for single axle semi- trailers in articulated vehicles exceeding tons and tandem axle semi- trailers in articulated vehicles exceeding tons gross vehicle weight Tab le — Towing vehicle with single rear axle height to face of fifth wheel from ground vehicle unladen and uncoupled © BSI 09- 999 i ii blank BS AU 3:1 970 Scope 1 This British Standard specifies clearance dimensions and the positions and heights of fifth wheel attachments fitted to the tractive units of articulated vehicles for the purpose of coupling semi- trailers It relates to towing vehicles with single rear axles not exceeding metres width and to semi- trailers fitted with king pins complying with BS AU 1) The standard applies to vehicles in normal road use and excludes vehicles used under cross- country conditions Dimensions The basic dimensions shall b e as given in Table , Tab le and Tab le 3, with reference to Figure and Figure Table and Table give preferred dimensions for the tractors and semi- trailers as follows: Table : preferred dimensions for single axle semi- trailers in articulated vehicles not exceeding tons and tandem axle semi- trailers not exceeding 24 tons gross train weights Table : preferred dimensions for single axle semi- trailers in articulated vehicles exceeding tons and tandem axle semi- trailers in articulated vehicles exceeding tons gross train weights NO TE Sub j ect to agreement between the user and the manufacturer, and where special conditions exist, the dimensions given in either Tab le or Tab le may b e selected as alternatives Table 3: gives the heights of the fifth wheel face from the ground Table — Preferred dimensions for single axle semi-trailers in articulated vehicles not exceeding 20 tons and tandem axle semi-trailers in articulated vehicles not exceeding 24 tons gross train weight Detail Symbol Dimensions in mm D min 50 D max max 305 max CA 64 62 CA-D 58 475 X1 60 max 52 max Y 54 max 370 max Z 63 600 D istance from fifth wheel face to point C on clearance plane h 00 Angle of forward inclination of clearance plane from point C µ 8° 8° W 61 max 560 max ¶ ° ° Position of fifth wheel from centre of rear axle D istance from point C on clearance plane at back of cab to centre line of rear axle D istance from centre line of king- pin to point C on clearance plane at back of cab or other chassis equipment D istance from fifth wheel to extreme rearwards proj ection of vehicle D istance from king- pin to extreme forward proj ection of semi- trailer D istance from king- pin rearwards to any proj ection likely to foul towing vehicle Maximum flat width of b ack of cab to permit 00 ° articulation of semi- trailer Clearance angle at sides of rear of cab to permit 00 ° articulation of semi- trailer 1) + BS AU , “Dimensions of – © BSI 09- 999 in diameter fifth wheel king pin for use with semi-trailers ” BS AU 3:1 970 Table — Preferred dimensions for single axle semi-trailers in articulated vehicles exceeding 20 tons and tandem axle semi-trailers in articulated vehicles exceeding 24 tons gross vehicle weight Detail Symbol Dimensions in Position of fifth wheel from centre of rear axle mm D min 305 D max 27 max 685 max CA 76 930 CA-D 64 625 X2 78 max 980 max Y 60 max 525 max Z 81 060 Distance from fifth wheel face to point C on clearance plane h 00 Angle of forward inclination of clearance plane from point C µ 8° 8° W 98 max 500 max ¶ Zero Zero Distance from point C on clearance plane at back of cab to centre line of rear axle Distance from centre line of king- pin to point C on clearance plane at back of cab or other chassis equipment Distance from fifth wheel to extreme rearwards proj ection of towing vehicle Distance from king- pin to extreme forward proj ection of semi- trailer Distance from king- pin rearwards to any proj ection likely to foul towing vehicle Maximum flat width of back of cab to permit 00 ° articulation of semi- trailer Clearance angle at sides of rear of cab to permit 00 ° articulation of semi- trailer Articulation Care shall be taken to ensure that when working to the positions and heights shown in the tables there shall be no fouling between the rear of the towing vehicle and its mudguards and the adj acent parts of the semi- trailer at a fore and aft articulation of up to plus and minus ° from the designed static position when the combination is in a straight line The clearance plane passing through point C (see Figure 2) at the back of the cab is a flat transverse plane sloping forward from point C at an angle of ° as shown and is intended to provide clearance for the ° fore and aft articulation requirement, and for semi- trailer clearance over chassis equipment mounted at the back of the tractor cab The cab profile shown in Figure permits a maximum semi- trailer articulation of 00 ° The clearances of vehicles built to the dimensions in Table are such that the flat back of cab may extend to the full legal width of metres Heights The heights of the fifth wheel face from the ground, with the vehicle unladen and uncoupled, shall be as given in Table when the fifth wheel is set at a minimum of in (1 50 mm) and a maximum of 27 in (685 mm) forward of the rear axle centre line The heights of intermediate positions shall be determined on a sloping line between the position in (1 50 mm) forward of the rear axle centre- line and the position 27 in (685 mm) forward of the rear axle centre- line NOTE These heights are based on the towing vehicle rear springs having a deflection of approximately in (75 mm) laden to unladen NOTE It is emphasized that advantage should be taken of the height tolerances specified only in extreme cases where coupling could not be otherwise effected © BSI 09- 999 BS AU 3:1 970 Table — Towing vehicle with single rear axle height to face of fifth wheel from ground vehicle unladen and uncoupled (see Figure ) (United Kingdom and overseas) Dimensions Tyre size at H D = in at (1 50 mm) in D = 27 in (685 mm) mm in mm 50 – 20 25 – 20 47 1 95 50 270 48 230 51 31 50 270 53 350 51 31 54 385 or tyres of equivalent diameter 00 – 20 or tyres of equivalent diameter 0 – 20 or tyres of equivalent diameter 1 – 20 or tyres of equivalent diameter NOTE The dimensions for H in this table are subj ect to a tolerance of plus and minus in (25 mm) Figure — Dimensions of towing vehicle with single rear axle and of semi-trailer © BSI 09- 999 BS AU 3:1 970 Figure — C learance dimensions between towing vehicle and semi-trailer to permit specified articulation © BSI 09- 999 blank BS AU 3:1970 BSI — British Standards Institution BS I is the indep endent national b ody res p ons ib le for p rep aring Britis h S tandards It p res ents the UK view on s tandards in E urop e and at the international level It is incorp orated b y Royal C harter Revisions Britis h S tandards are up dated b y amendment or revis ion Us ers of Britis h S tandards should make s ure that they p oss es s the latest amendments or editions It is the constant aim of BS I to imp rove the quality of our p roducts and services We would b e grateful if anyone finding an inaccuracy or amb iguity while us ing this Britis h S tandard would inform the S ecretary of the technical committee 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