Bsi bs au 028 1964 (2000)

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[.]

Sta nd a r d No.6 )

U C 6 9.1 0 3.5:6 9.1 0 3.3

This Bri sh Stan ard, ha ing

b en a pro ed b the

Automo ileIn ustry

Stan ardsCommi e an

en or ed b the Chairman of

theEng ine ring Divisional

Cou cil, was published

u derthe uthoriy of the

GeneralCou cil of the

Inst utonon

1 Ju e1 6

© BSI 0 -2 0

The folowing BSI reference

relates to the work on this

stan ard:

Commi e reference AUE/

-ISBN 0 5 0 3 5 1 3

Am endm ents is ued sinc publ cation

B

This British Stand rd which is publshed u der the authority of the Automobie

Ind ustry Stand ards Commit e of the BSI, is b sed upon

d ata-she t SMMT6 :19 7 of the Society of Motor Man facturer and

Tra er Ltd The requirements of this stand rd , which relate only to v ehicles

used on the publc hig hway s, are intended to ensure the ma imum deg re of

inter hang ea i ity betwe n commer ial and Gov ernment dep rtment and

Serv ices stand ard s

Towing jaws ma be forg ed( as shown in Fig ure) or cast

The material specifications are for the minimum qual ties ac epta le, and do not

exclude the use of other materials prov id ed that these are at least eq ual in q ual ty

so that roa safety is not imp ired

This stand ard should be used in conju ction with BS AU29

1)

The jaw has be n

desig ned to ac ommod te a drawb r ey e of3in internal d iameter

and 1 5

/

8

in stock

The stand ard a ples to con ections to trai er of5–35 tons g ros weig ht

Thespecification for a towing jaw for con ections to traier of5 14 tons g ros

weig ht is g iv en in BS AU26

2)

and for traier of2– tons g ros in BSA U24

3)

N T If i is re uired to conv ert the fig ures in this stan ard fom Bri sh u is into metric u is i

is recommen ed that the conv r ion factor an ta les contained in BS3 0,“Conver sion factor s a d

ta ble ”, b used Attenton is drawn to BS2 5 , “Pr ecis conver sion of inch a d metr ic sizes on

en ine r in d r awin s”

A British Stand ard d oes not purport to includ e al the neces ary prov isions of a

contract User of British Stand rd s are responsible for their cor ect a plcation

Com pl anc with a British Standard does not ofitself confer im m unity

f om leg al o l g ations

Sum mary of pag es

This document comprises a f ont cov er, an insid e font cov er, p g esi andi ,

p g es1 and2 an a b ck cov er

This stand rd has be n up ated ( se copy rig ht d ate) an ma hav e ha

amendments incorporated This wi l be indicated in the amendment ta le on the

inside f ont cov er

1)

BS AU2 ,“Dr awbar ye a d for ecar r ia e pins for on eton betwen tr aier s of5–35 tons

gr os weig t a d towin vehicle ”

2)

BS AU2 ,“Towin jaw for us betwe n tr aier s of5– 4 tons gr os weig t a d towin vehicle”

3)

BS AU2 ,“Towin con e tons for tr aier s of2–5 tons gr os weig t

1 Scope

This British Stand rd specifies the b sic

dimensions and q ual ty of materials for a towing jaw

an its mou ting s, for use in connection betwe n a

towing v ehicle an a trai er of5 3 tons g ros

weig ht

The g ros weig ht refer to g ros la en train weig hts

where more than one traier is drawn

2 Materia ls

The jaw shal be mad e f om a material of q ual ty not

les than BS9 0

4)

En3A for the forg ed jaw, or

BS5 2A

5)

for the cast jaw, both materials to be in

their normalz d condition

The towing pin shal be ma e fom a material of

q ualty not les than BS9 0

4)

En16S

Dimensions shal be as shown in the Fig ure

Thering ed d imensions are es ential for

inter hang ea i ity , other d imensions a ply to the

forg ed jaw and are for g uid ance only

NOT The d imensions sp cified for the forg ed jaws ha e b en

calculated on the b sis of the total yield streng th b ing not les

than two thirds of the g ros weig ht b ing towed, I is neces ary

that any ther p rts not cov ered b this stan ard,con ectng the

coupling to the towing ehicle shal hav e a similar streng th

4 Desig n

An eficient safety locking dev ice shal be prov ided

as indicated in the Fig ure to prev ent ac idental

extraction of the towing pin fom the jaw

The jaw shal be so d esig ned that a b r1

3

/

4

in

diameter ma be p s ed f e ly betwe n the pin and

the insid e face of the jaw( se Fig ure)

The jaw shal be mounted with four bolts,

3

/

4

in

diameter, at4in ×4 in centres This render it

inter hang ea le in mou ting with ho ks specified in

BS AU25

6)

and BS AU27

7)

and with certain

Gov ernment dep rtment and Serv ices stand rd

ho ks

Bolts and nuts shal comply with:

i BS10 3, thr ea d ed B SF, cod e symbol R , or

)

i ) BS17 8, thr ea d ed UNF, cod e symbol R

9)

The n ts shal be secured either b pe ning the end

of the bolt or b fit ing a positiv e locking d ev ice such

as a safe locking n t or a slot ed n t and spl t pin

6 Ma rking

The fol owing wording , in clear let ering

3

/

8

in hig h,

raised or impres ed, shal be marked on each towing

jaw:

“TO TOW3 TONS GROS ” on one side, and on

the other side BS AU28”

4)

BS9 0, “Wr ou ht stels in the for m of bar s, bi ets a d for gin s, up to6in r uln s cton, for a tomo ie a d gener al

en ine r in pur pos s En sr ie”

5)

BS5 2, (nclu ed in BS3 0 ) “Car bon ste l castn s for gener al en iner in pur pos s”

6)

BS AU2 , “Towin ho k for us betwen tr aier s of5–14 tons gr os weig t a d towin vehicle”

7)

BS AU2 , “Towin ho k for us betwen tr aier s of5–35 tons gr os weig t a d towin vehicle”

8)

BS1 8 ,“Pr ecision hexa on b ls, s r ews a d n ts”

9)

BS1 6 ,“Unified pr ecision hexa on b ls,s r ews a d n ts UNC a d UNF thr ea nor mal s r ie ) ”

B

b

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London

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