BRITISH STANDARD AUTOMOBILE SERIES BS AU 138a 1980 Specification for Dimensions of “contact” type couplings for air pressure braking systems on trailers and semi trailers and their towing vehicles, an[.]
BRITIS H S TAND ARD AUTO MO BILE S E RIE S BS AU 8a: 980 Specification for D imensions of “contact” type couplings for air pressure b raking systems on trailers and semi-trailers and their towing vehicles, and the arrangement of these couplings on articulated and drawbar comb inations UD C 62 1 : 62 – BS AU 8a: 980 Fore word This British Standard has been prepared under the direction of the Automobile Standards Committee and supersedes BS AU 5: 963, except in regard to its application to vacuum brake systems, and BS AU 38: 967 BS AU 38: 967 is withdrawn on publication of this edition BS AU is not withdrawn This edition of this standard makes no fundamental changes to these earlier standards but takes account of changes in normal practice since they were issued and clarifies certain details, particularly with regard to the operation of the self- sealing valves The form of coupling and layout of couplings specified in this standard constitute a system for use on any vehicle having a two- or three- line air pressure brake system 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 British Standard, having been prepared under the direction of the Automobile Standards Committee, was 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 published under the authority of the Executive Board and comes into effect on Ame ndme nts issue d since p ub lication 28 November 980 © BSI 02- 2000 The following BSI references relate to the work on this standard: Committee reference AUE/Draft for comment 79/71 031 DC IS B N 80 1 6 Amd No Date of issue Comments BS AU 138a:1980 Contents Page Foreword Scope References General requirements Articulated vehicles D rawbar comb inations Figure — C type male coupling with self- sealing valve Figure — C type female coupling with operating adaptor Figure — C type male coupling Figure — C type female coupling with self- sealing valve Figure — CA type female coupling with self- sealing valve Figure — CA type male coupling Figure — Articulated vehicle braking connections Figure — D rawb ar combination b raking connections © BSI 02 - 000 Inside front cover 10 Tab le — Couplings Tab le — Summary of dimensions for articulated vehicles i ii blank BS AU 8a: 980 Whoever installs the fifth wheel or towing hook on S cop e This British Standard specifies the dimensions necessary to ensure the correct mating of “contact” couplings for connecting the air pressure brake systems of towing vehicles to trailers or semi- trailers, and the layout of these connections Two types of “contact” coupling are specified: the C type, and the CA type; these two types of coupling are intentionally physically non- interchangeable This standard specifies the following: the chassis shall supply, and fit on to the towing vehicle, the couplings and self- sealing valves, and for articulated operation, the flexible tubes and their stowing devices The manufacturer of the towing vehicle shall supply and fit temporary blanking plugs to the female threaded ends of the fixed pipes, ready for flexible tube connections, for articulated operation, or for the couplings, in the case of drawbar combinations NOTE When vehicles are uncoupled, the connecting a) the form and dimensions for a C type “contact” tubes/hoses should be safely housed in their stowing devices coupling and for the self- sealing valve, operating C olour cod ing probe and operating adaptor that shall be fitted shall be as follows: to one or the other of the members of the coupling to enable it to be used on the service or emergency line of a two- line or three- line air pressure system; b) the form and dimensions for a CA type “contact” coupling and for the self- sealing valve a) service line, If a colour is used for a line, it yellow or orange; b) emergency line, c) secondary line, red; blue C oup lings 3.4.1 General The type of coupling to be used on on the female coupling to enable it to be used on each line at the appropriate location shall be as the secondary line of a three- line air pressure specified in Table The couplings shall comply with brake system; the form and dimensions specified in the figure c) the general layout and location of flexible referred to in the relevant entry of Table As a hoses/tubes and C type couplings for vehicles requirement of Table , all couplings that are fitted using a two- line air pressure brake system and of to, or have a fixed connection with the towing the additional secondary line and CA type vehicle shall have a self- sealing valve With coupling used in a three- line system reference to Figure to Figure 6, all couplings shall be threaded to a depth of mm full length of thread Some entries in Table specify the inclusion Re fe re nce s The following standards publications are referred to in this standard ISO metric screw threads — Part 3: Limits and tolerances for fine pitch threads (constant pitch series) BS 3643, Specification for nylon tube — Part 2: Plasticized and unplasticized nylon tubing types 1 and 12 for use primarily in the automobile industry BS 5409, 3.4.2 Self-sealing valve A male coupling fitted with a self- sealing valve shall be so arranged to open only when the assembly is connected to a female coupling A female coupling fitted with a self- sealing valve shall be so arranged to open only when the assembly is connected to a male coupling A male coupling (fitted with a self- sealing valve) on ensure that the assembly is coupled only to a female The requirements of this standard apply equally to both two- and three- line air pressure brake systems, except that in the case of a two- line system, the secondary line, its couplings and its stowing device shall be omitted Manufacture rs’ re sp onsib ility are as follows a service line shall be conspicuously marked to Ge ne ral requireme nts Introductio n of a self- sealing valve or operating adaptor in the coupling; the requirements for these components The coupling that has an operating adaptor 3.4.3 Operating adaptor The operating adaptor fitted to the female coupling of a service line shall be of the type shown in Figure and shall incorporate an integral tip The tip shall be so arranged that it will open the self- sealing valve in the male member manufacturer of the trailer shall supply and fit the when the assembly is connected to it For this pipes and couplings on the trailer and shall provide purpose, the integral tip of the adaptor shall: hoses in the case of drawbar trailers Every trailer shall be fitted with an operating adaptor on the service line coupling whether or not the trailer is intended to be coupled to a towing vehicle with a self- sealing valve © BSI 02- 2000 a) be positioned according to the dimension specified in Figure 2(a); and b) be so shaped that it proj ects into the nozzle of the male member without fouling it; and BS AU 38a:1 980 Table — C ouplings C oupling type Coupling location Service line Articulated vehicle Drawbar combination Emergency line Secondary line Coupling on Female C type + Male C type Male CA type semi- trailer operating adaptor (Figure 3) (Figure 6) (Figure 2) Coupling on rear Male C type + Female C type + Female CA type + of flexible tube self- sealing valve self- sealing valve self- sealing valve (Figure ) (Figure 4) (Figure 5) Coupling on Male C type + Female C type + Female CA type + towing vehicle self- sealing valve self- sealing valve self- sealing valve (Figure ) (Figure 4) (Figure 5) Coupling on front Female C type + Male C type Male CA type of trailer- mounted operating adaptor (Figure 3) (Figure 6) hose (Figure 2) c) offer the minimum restriction to the flow of air; 4.2 Fixed couplings on semi-trailer and 4.2.1 d) be sufficiently robust or of a material to resist for the service line and emergency line shall be the effects of corrosion fitted on the front of the semi- trailer as nearly as Ho rizontal location of coup lings The couplings practicable equidistant from the vertical centreline Articulated vehicles of the semi- trailer and from 200 mm to 400 mm 4.1 Arrangement and location of braking connections Braking connections on articulated vehicles shall consist of: G ) The secondary line coupling shall be between the service and emergency couplings 4.2.2 a) fixed pipes on the towing vehicle; Height of coup lings The couplings shall proj ect at an angle of ° to ° downwards from the b) flexible tubes attached to these pipes; horizontal and the height to the centreline of the c) flexible tube stowing devices mounted on the couplings when fitted shall be between 50 mm towing vehicle; and 600 mm above the face of the fifth wheel d) for each line, a set of mating couplings, one of (dimension which is attached to the flexible tube, the other being fixed to the semi- trailer The location of the braking connections, flexible tubes and stowing devices on the towing vehicles and semi- trailers using the two- or three- line system shall be as shown in Figure NOTE should be located in a convenient position (see 4.3.2 ) Dimensions shown in Figure shall be as specified in Table Table — Summary of dimensions for articulated vehicles B C G mm mm mm mm +1 50 line pipe shall be fitted as nearly as practicable equidistant from the centreline of the towing vehicle G ) The pipe for the secondary line shall be between the service pipe and emergency pipe 4.3.1 Bore The pipes shall have a nominal bore of mm for the service line and the emergency line, and mm for the secondary line Pip e ends The pipe ends shall have an M22 × 5–6H female thread complying with the A H The towing in Figure The service line pipe and emergency 4.3.1 Dimension (see Figure 7) 50 to 600 Horizo ntal locatio n of p ip es vehicle shall be fitted with three pipes as shown and from 200 mm to 400 mm apart (dimension The flexible tube supports are not shown in Figure and 50 to 50 ) Pipes 4.3.1 semi- trailer B 4.3 Fixed connection on towing vehicle 4.3.1 The coupling interface shall thus be at the apart (dimension requirements of BS 3643- and shall be tapped to a depth of mm full length of thread 200 to 400 © BSI 02- 2000 BS AU 8a: 980 Flexib le tub e stow ing dev ices Stowing devices The location of the braking connections and flexible shall be provided on the back of the cab, shall hoses on the towing vehicles and drawbar trailers support the flexible tubes as far as is possible clear using the two- or three- line system shall be as of the chassis frame of the towing vehicle when they shown in Figure are not connected to the semi- trailer, shall afford NOTE adequate protection against damage and shall should be located in a convenient position (see inhibit entry of moisture and dirt Fixe d coup lings on tow ing ve hicle Fle xib le tub e s The flexible hose supports are not shown in Figure and Ho rizontal location of coup lings Typ e, attachm ent and sup p ort The tube shall be flexible nylon tube complying with the 5.3.2) The couplings for the service line and emergency line shall be fitted on the rear of the towing vehicle as nearly as requirements of BS 5409- The coiled nylon tube practicable equidistant from the vertical centreline shall be arranged generally as shown in Figure of the vehicle and from 550 mm to 700 mm apart Any support shall be flexible, such that the slack of (dimension the tube does not make contact with any part of the secondary line shall be on the same side as the towing vehicle or its fittings emergency coupling Dimension Tub e ends The ends of the towing ) , located as shown in Figure The C Z shall be 75 mm minimum vehicle- mounted tubes that are to receive the The face of the fixed part of the female C type couplings shall be male M22 × 5–6g threaded coupling to the centreline of the towing pin connections, threaded to a length of mm, (dimension complying with the requirements of BS 3643- and 50 mm minimum, with the other couplings 4.4.3 Dimensions Bo re B ) shall be 50 mm maximum mounted approximately in line, as shown in Figure The nominal bore of the flexible tube shall be as follows: Height of coup lings The couplings shall proj ect at an angle of ° to ° downwards from the a) for service line and emergency line, mm; horizontal and shall all be on the same horizontal b) for secondary line, mm plane The centreline of the couplings shall The coiled nylon tube shall be of Length sufficient length so that it will readily stretch to the dimension J plus 750 mm, where J is the distance from the back of the cab (or any proj ection from the cab likely to foul the semi- trailer) to the centreline of the rear axle, as shown in Figure Tilt cab s Special provision shall be made for the tube supports and stowage devices on an articulated vehicle with a tilt cab D rawb ar comb inations Arrange me nt and lo cation of b raking co nne ctions Braking connections on drawbar combinations shall consist of: be 200 mm maximum and mm minimum vertically below the centreline of the towing j aw (dimension A ) Pip e s and co nne ctio ns on drawb ar traile r 5.3.1 Pipes and hoses Locatio n Flexible hoses shall be run directly from the trailer forecarriage, and shall be secured at a point near the apex of the drawbar (see Figure 8) The length of hoses shall be such that, when coupled to the towing vehicle, the maximum angle of the drawbar centreline with the longitudinal axis of the towing vehicle of 90 ° either way can be attained while at the same time permitting a vertical angular movement of 20 ° minimum above or below the a) flexible hoses taken directly from the trailer horizontal position For angles less than 60 ° to forecarriage; either side there shall be complete freedom of lateral b) stowing devices mounted on the drawbar trailer; c) for each line, a set of mating couplings, one of which is attached to the flexible hose, the other being fitted to the towing vehicle The coupling interface shall thus be at the towing vehicle movement without any tension on the hoses When in the straight ahead position with the drawbar at its normal operating height, any hose shall not sag below a line, proj ected from the face of the fixed part of the couplings, at an angle of 20 ° below the horizontal centreline of the coupling Bore The pipes and hoses shall have a nominal bore of mm for the service line and the emergency line, and mm for the secondary line © BSI 02- 2000 BS AU 38a:1 980 3.1 Hos e ends The ends of the trailer- mounted hos es that are to receive the coup lings shall b e male M2 × –6g threaded connections , threaded to a length of mm, comp lying with the requirements 5.3.2 Hos e stow ing dev ices S towing devices shall b e p rovided on the trailer s o as to s up p ort the hos es , shall afford adequate p rotection agains t damage and s hall inhib it the entry of mois ture and dirt of BS 643 - NO TE D etail dimens ions for the coup ling are given in Figure All dimens ions in millimetres Figure — C type male coupling with self-sealing valve © BS I - 00 BS AU 138a:1980 NOTE Detail dimensions for the coupling are given in (b) (a) General arrangement of coupling with operating adaptor fitted (b) Detail dimensions of coupling All dimensions in millimetres Figure — C type female coupling with operating adaptor © BSI 02- 2000 BS AU 38a:1 980 Figure — C type male coupling NOTE Detail dimensions for the coupling are given in Figure 2(b) All dimensions in millimetres Figure — C type female coupling with self-sealing valve © BSI 02- 2000 BS AU 38a:1 980 NOTE Detail dimensions for the coupling are given in (b) (a) General arrangement of coupling with self- sealing valve (b) Detail dimensions of coupling All dimensions in millimetres Figure — C A type female coupling with self-sealing valve © BSI 02- 2000 BS AU 138a:1980 Figure — CA type male coupling © BSI 02 - 000 BS AU 138a:1980 Figure — Articulated vehicle braking connections © BSI 02 - 000 BS AU 138a:1980 Figure — Drawbar combination braking connections 10 © BSI 02 - 000 blank BS AU 138a:1980 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 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