Regulation No. 55-01

Name:Regulation No. 55-01
Description:Towing Couplings, Forks, Eyes, Fifth Wheels etc.
Official Title:Uniform Provisions Concerning the Approval of: Mechanical Coupling Components of Combinations of Vehicles.
Country:ECE - United Nations
Date of Issue:1983-01-18
Amendment Level:01 Series, Supplement 6
Number of Pages:83
Vehicle Types:Bus, Car, Component, Heavy Truck, Light Truck, Trailer
Subject Categories:Miscellaneous
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Keywords:

coupling, vehicle, device, class, test, paragraph, drawbar, couplings, annex, approval, type, devices, mechanical, component, force, towing, figure, maximum, wheel, vertical, ball, regulation, manufacturer, components, requirements, mass, position, eyes, horizontal, dimensions, centre, standard, trailer, mounting, case, fitted, permissible, static, vehicles, pin, remote, tests, load, values, technical, table, locking, hook, axle, eye

Text Extract:

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E/ECE/324
) Rev.1/Add.54/ Rev.2/Amend.2
E/ECE/TRANS/505 )
February 22, 2017
STATUS OF UNITED NATIONS REGULATION
ECE 55-01
UNIFORM PROVISIONS CONCERNING THE APPROVAL OF:
MECHANICAL COUPLING COMPONENTS OF COMBINATIONS OF VEHICLES
Incorporating:
00 series of amendments
Date of Entry into Force: 01.03.83
Supplement 1 to the 00 series of amendments
Date of Entry into Force: 12.12.93
01 series of amendments
Date of Entry into Force: 16.09.01
Corr. 1 to the 01 series of amendments
Dated: 13.03.02
Supplement 1 to the 01 series of amendments
Date of Entry into Force: 17.03.10
Supplement 2 to the 01 series of amendments
Date of Entry into Force: 30.01.11
Supplement 3 to the 01 series of amendments
Date of Entry into Force: 13.04.12
Supplement 4 to the 01 series of amendments
Date of Entry into Force: 08.10.15
Supplement 5 to the 01 series of amendments
Date of Entry into Force: 08.10.16
Supplement 6 to the 01 series of amendments
Date of Entry into Force: 09.02.17

REGULATION NO. 55
UNIFORM PROVISIONS CONCERNING THE APPROVAL OF MECHANICAL
COUPLING COMPONENTS OF COMBINATIONS OF VEHICLES
CONTENTS
REGULATION
1. Scope
2. Definitions
3. Application for Approval of a Mechanical Coupling Device or Component
4. General Requirements for Mechanical Coupling Devices or Components
5. Application for Approval of a Vehicle fitted with a Mechanical Coupling Device or Component
6. General Requirements for Vehicles fitted with a Mechanical Coupling Device or Component
7. Markings
8. Approval
9. Modifications of the Mechanical Coupling Device or Component, or of the Vehicle and Extension of
Approval
10. Conformity of Production Procedures
11. Penalties for Non-conformity of Production
12. Production Definitively Discontinued
13. Transitional Provisions
14. Names and Addresses of Technical Services Responsible for Approval Tests, and of Type
Approval Authorities

1. SCOPE
REGULATION NO. 55
UNIFORM PROVISIONS CONCERNING THE APPROVAL OF MECHANICAL
COUPLING COMPONENTS OF COMBINATIONS OF VEHICLES
1.1. This Regulation lays down the requirements which mechanical coupling devices and
components shall meet in order to be regarded internationally as being mutually compatible.
1.2. This Regulation applies to devices and components intended for:
1.2.1. Motor vehicles and trailers intended to form a combination of vehicles
1.2.2. Motor vehicles and trailers intended to form articulated vehicles , where the vertical load
imposed on the motor vehicle by the trailer does not exceed 200kN,
1.3. This Regulation applies to:
1.3.1. Standard devices and components as defined in Paragraph 2.3.;
1.3.2. Non-standard devices and components as defined in Paragraph 2.4.;
1.3.3. Non-standard miscellaneous devices and components as defined in Paragraph 2.5.
2. DEFINITIONS
For the purposes of this Regulation:
2.1. "Mechanical Coupling Devices and Components" means all those items on the frame,
load-bearing parts of the bodywork and the chassis of the motor vehicle and trailer by
means of which they are connected together to form the combination of vehicles or the
articulated vehicles. Fixed or detachable parts for the attachment or operation of the
mechanical coupling device or component are included.
2.2. Automatic coupling requirement is achieved if reversing the towing vehicle against the trailer
is sufficient to engage the coupling completely, to lock it automatically and to indicate proper
engagement of the locking devices without any external intervention.
In the case of hook type couplings automatic coupling requirement is achieved if opening
and closing of the coupling locking device takes place without any external intervention
when the drawbar eye is inserted into the hook.
2.3. Standard mechanical coupling devices and components conform to standard dimensions
and characteristic values as given in this Regulation. They are interchangeable within their
class, independent of manufacturer.
2.4. Non-standard mechanical coupling devices and components do not conform in all respects
to the standard dimensions and characteristic values given in this Regulation but can be
connected to standard coupling devices and components in the relevant class.

2.6.4.4. Class D50-X Non-standard 50mm pin diameter drawbar eyes.
2.6.5.
Class E
Non-standard drawbars comprising overrun devices
and similar items of equipment mounted on the front
of the towed vehicle, or to the vehicle chassis, which
are suitable for coupling to the towing vehicle by
means of drawbar eyes, coupling heads or similar
coupling devices – see Annex 5, Paragraph 5.
Drawbars may be hinged to move freely, in a vertical plane and not support any vertical load
or be fixed in a vertical plane so as to support a vertical load (Rigid drawbars). Rigid
drawbars can be entirely rigid or be flexibly mounted.
Drawbars may comprise more than one component and may be adjustable or cranked.
This Regulation applies to drawbars which are separate units, not an integral part of the
chassis of the towed vehicle.
2.6.6.
Class F
Non-standard drawbeams comprising all components
and devices between the coupling devices, such as
coupling balls and drawbar couplings, and the frame
(for example the rear cross member), the loadbearing
bodywork or the chassis of the towing vehicle
– see Annex 5, Paragraph 6.
2.6.7.
Class G
Fifth wheel couplings are plate type couplings having
an automatic coupling lock and are fitted to the
towing vehicle for connecting with a 50mm diameter
fifth wheel coupling pin fitted to a semi-trailer – see
Annex 5, Paragraph 7.
2.6.7.1. Class G50 Standard 50mm pin diameter fifth wheel couplings.
2.6.7.2.
Class G50-X
Non-standard
50mm
pin
diameter
fifth
wheel
couplings.
2.6.8.
Class H
Fifth wheel coupling pins, 50mm diameter, are
devices fitted to a semi-trailer to connect with the fifth
wheel coupling of the towing vehicle – see Annex 5,
Paragraph 8.
2.6.8.1.
Class H50-X
Non-standard 50mm pin diameter fifth wheel coupling
pins.
2.6.9. Class J Non-standard mounting plates comprising all
components and devices for attaching fifth wheel
couplings to the frame or chassis of the towing
vehicle. The mounting plate may have provision for
moving horizontally, that is to form a sliding fifth
wheel – see Annex 5, Paragraph 9.
2.6.10.
Class K
Standard, hook type couplings intended for use with
appropriate Class L type toroidal drawbar eyes – see
Annex 5, Paragraph 10.

2.11. The characteristic values D, D , S, V and U are defined or determined as:
2.11.1. The D or D value is the theoretical reference value for the horizontal forces in the towing
vehicle and the trailer and is used as the basis for horizontal loads in the dynamic tests.
For mechanical coupling devices and components not designed to support imposed vertical
loads, the value is:
T ⋅ R
D = g
T + R
[ kN]
For mechanical coupling devices and components for centre axle trailers as defined in 2.13,
the value is:
D
T ⋅ C
= g
T + C
[ kN]
For fifth wheel couplings of Class G, fifth wheel coupling pins of Class H and mounting
plates of Class J, as defined in Paragraph 2.6., the value is:
where:
0.6 ⋅ T ⋅ R
D = g
T + R − U
[ kN]
T
R
C
is the technically permissible maximum mass of the towing vehicle, in tonnes. Where
relevant, this includes the vertical load imposed by a centre axle trailer.
is the technically permissible maximum mass, in tonnes, of a trailer with drawbar free
to move in a vertical plane, or of a semi-trailer.
is the mass, in tonnes, transmitted to the ground by the axle or axles of the centre
axle trailer, as defined in Paragraph 2.13., when coupled to the towing vehicle and
loaded to the technically permissible maximum mass . For Category O and O
centre axle trailers the technically permissible maximum mass will be that declared
by the manufacturer of the towing vehicle.
g is the acceleration due to gravity (assumed to be 9.81m/s )
U is as defined in Paragraph 2.11.2.
S is as defined in Paragraph 2.11.3.
2.11.2. The U value is the vertical mass, in tonnes, imposed on the fifth wheel coupling by the
semi-trailer of technically permissible maximum mass

Figure 1
Dimensions of the Centre Axle Trailer
2.12. Symbols and Definitions used in Annex 6 to this Regulation
A
C
D
D
R
T
F
F
F
S
U
V
a
e
= maximum permitted axle mass of the steered axle in tonnes.
= mass of centre axle trailer in tonnes – see Paragraph 2.11.1. of this Regulation.
= D value in kN – see Paragraph 2.11.1. of this Regulation.
= D value in kN for centre axle trailers – see Paragraph 2.11.1. of this Regulation.
= mass of towed vehicle in tonnes – see Paragraph 2.11.1. of this Regulation.
= mass of towing vehicle in tonnes – see Paragraph 2.11.1. of this Regulation.
= static lifting force in kN.
= horizontal component of test force in longitudinal axis of vehicle in kN.
= vertical component of test force in kN.
= static vertical mass in kg.
= fifth wheel imposed vertical mass in tonnes.
= V-value in kN – see Paragraph 2.11.4. of this Regulation.
= equivalent vertical acceleration factor at the coupling point of centre axle trailers
depending on the type of suspension of the rear axle(s) of the towing vehicle – see
Paragraph 2.11.4. of this Regulation.
= longitudinal distance between the coupling point of coupling balls which can be
dismantled and the vertical plane of the fixing points (see Figure 20c to 20f) in mm.

3. APPLICATION FOR APPROVAL OF A MECHANICAL COUPLING DEVICE OR
COMPONENT
3.1. The application for approval shall be submitted by the holder of the trade name or mark, or
by his duly accredited representative.
3.2. For each type of mechanical coupling device or component the application shall be
accompanied by the following information, for example, by means of the Communication
form given in Annex 1:
3.2.1. Details of all manufacturer's or supplier's trade names or marks to be applied to the coupling
device or component;
3.2.2. Three sets of drawings which are sufficiently detailed to define the device or component and
which specify how it is to be fitted to the vehicle, the drawings shall show the position and
space provided for the approval number and other marking as given in Paragraph 7;
3.2.3. A statement of the values of D, D , S, V and U as applicable and as defined in
Paragraph 2.11.
For Class A towing brackets a statement of the maximum permissible towing vehicle and
trailer masses and the maximum permissible static vertical imposed load on the tow ball as
advised by the manufacturer of the towing vehicle;
3.2.3.1. The characteristic values shall be at least equal to those applicable to the maximum
permissible towing vehicle, trailer and combination masses.
3.2.4. A detailed technical description of the device or component, specifying, in particular, the
type and the materials used;
3.2.5. Restrictions on the vehicles to which the coupling may be fitted – see Annex 1,
Paragraph 12, and Annex 5, Paragraph 3.4.;
3.2.6. One sample, plus additional samples as requested by the Type Approval Authority or
technical service;
3.2.7. All samples shall be fully finished with the final surface treatment applied. However, if the
final treatment is by painting or epoxy powder coating, this should be omitted;
3.2.8. In the case of a mechanical coupling device or component designed for a specific vehicle
type, the manufacturer of the device or component shall also submit the installation data,
according to Annex 2, Appendix 1, given by the vehicle manufacturer. The Approval
Authority or Technical Service may also request that a vehicle representative of the type be
submitted.

4.7. For devices and components of Class A, Class K or Class S, if applicable, for use with
trailers of maximum permissible mass not exceeding 3.5t, and which are produced by
manufacturers not having any association with the vehicle manufacturer and where the
devices and components are intended for fitting in the after-market, the height and other
installation features of the coupling shall, in all cases, be verified by the Type Approval
Authority or Technical Service in accordance with Annex 7, Paragraph 1.
4.8. For heavy duty and other non-standard miscellaneous coupling devices or components,
Class S and Class T, the relevant requirements in Annexes 5, 6 and 7 for the closest
standard or non-standard device or component shall be used.
5. APPLICATION FOR APPROVAL OF A VEHICLE FITTED WITH A MECHANICAL
COUPLING DEVICE OR COMPONENT
5.1. Where a vehicle manufacturer applies for approval of a vehicle fitted with a mechanical
coupling device or component or authorises the use of a vehicle for towing any form of
trailer, then, at the request of a bona fide applicant for possible type approval for a
mechanical coupling device or component, or of the Type Approval Authority or Technical
Service of a Contracting Party, the vehicle manufacturer shall readily make available to that
inquirer or Authority or Technical Service, such information as required in Annex 2,
Appendix 1, to enable a manufacturer of a coupling device or component to properly design
and manufacture a mechanical coupling device or component for that vehicle. At the request
of a bona fide applicant for possible type approval for a mechanical coupling device or
component, any information given in Annex 2, Appendix 1 which is held by the Type
Approval Authority shall be released to that applicant.
5.2. The application for approval of a vehicle type with regard to the fitting of a mechanical
coupling device or component shall be submitted by the vehicle manufacturer or by his duly
accredited representative.
5.3. It shall be accompanied by the following information to enable the Type Approval Authority
to complete the communication form given in Annex 2.
5.3.1. A detailed description of the vehicle type according to Annex 2, Appendix 1 and of the
mechanical coupling device or component and, at the request of the Type Approval
Authority or Technical Service, a copy of the approval form for the device or component;
5.3.2. Deleted.
5.3.2.1. Deleted.
5.3.3. Three sets of drawings which are sufficiently detailed to identify the device or component
and which specify how it is to be fitted to the vehicle; the drawings shall show the position
and space provided for the approval number and other marking as given in Paragraph 7.;
5.3.4. A detailed technical description of the device or component, specifying, in particular, the
type and the materials used;
5.3.5. A statement of the values of D, D , S, V and U as applicable and as defined in
Paragraph 2.11.;
5.3.5.1. The characteristic values shall be at least equal to those applicable to the maximum
permissible towing vehicle, trailer and combination masses.

7.5. If the application of the mechanical coupling device or component is restricted in any way,
for example, if it is not to be used with steering wedges, then that restriction shall be marked
on the device or component.
7.6. All markings shall be permanent and legible when the device or component is installed on
the vehicle.
8. APPROVAL
8.1. If the sample(s) of a type of mechanical coupling device or component meets (meet) the
requirements of this Regulation, approval shall be granted subject to the requirements of
Paragraph 10 being satisfactorily met.
8.2. An approval number shall be assigned to each type approved. Its first two digits (at present
01) shall indicate the series of amendments incorporating the most recent major technical
amendments made to the Regulation at the time of issue of the approval. The same
Contracting Party may not assign the same number to another type of device or component
referred to in this Regulation.
8.3. Notice of approval or of extension, refusal or withdrawal of approval or of production
definitely discontinued, relating to a type of mechanical coupling device or component
approved pursuant to this Regulation, shall be communicated to the Parties to the 1958
Agreement applying this Regulation, by means of a communication form conforming to the
model in either Annex 1 or Annex 2 to this Regulation.
8.4. In addition to the mark prescribed in Paragraph 7.1., there shall be affixed to every
mechanical coupling device or component approved under this Regulation, in the space
referred to in Paragraph 7.2., an approval mark as described in Paragraph 8.5.
8.5. The approval mark shall be an international approval mark comprising:
8.5.1. A circle surrounding the Letter "E", followed by the distinguishing number of the country
which has granted approval,
8.5.2. The approval number prescribed in Paragraph 8.2.;
8.5.3. The approval mark and number shall be arranged as shown in the example in Annex 3.

12. PRODUCTION DEFINITIVELY DISCONTINUED
If the holder of the approval completely ceases to manufacture a type of mechanical
coupling device or component approved in accordance with this Regulation, he shall so
inform the Type Approval Authority or Technical Service which granted the approval. Upon
receiving the relevant communication, that Type Approval Authority or Technical Service
shall inform thereof the other Contracting Parties to the 1958 Agreement applying this
Regulation by means of a communication form conforming to the model in either Annex 1 or
Annex 2 to this Regulation.
13. TRANSITIONAL PROVISIONS
13.1. Until the United Nations Secretary-General is notified otherwise, Contracting Parties
applying this Regulation that are Member States of the European Union declare that, in
relation to mechanical coupling devices and components, they will only be bound by the
obligations of the Agreement to which this Regulation is annexed with respect to such
devices and components intended for vehicles of categories other than M .
13.2. As from the official date of entry into force of Supplement 5 to the 01 series of amendments
to this Regulation, no Contracting Party applying this Regulation shall refuse to grant or
refuse to accept type approvals according to Supplement 5 to the 01 series of amendments.
13.3. Until twelve months after the date of entry into force of the Supplement 5 to the 01 series of
amendments, Contracting Parties applying this Regulation can continue to grant type
approvals according to the 01 series of amendments to this Regulation without taking into
account the provisions of Supplement 5.
14. NAMES AND ADDRESSES OF TECHNICAL SERVICES RESPONSIBLE FOR
APPROVAL TESTS, AND OF TYPE APPROVAL AUTHORITIES
14.1. The Contracting Parties to the 1958 Agreement applying this Regulation shall communicate
to the United Nations Secretariat the names and addresses of the Technical Services
responsible for conducting approval tests and of the Type Approval Authorities which grant
approval and to which forms certifying approval or extension or refusal or withdrawal of
approval, or production definitively discontinued, issued in other countries, are to be sent.

9.2. Characteristic values: ...................................................................................................................
9.2.1. Primary values: .............................................................................................................................
D ................................... kN
D ................................ kN
S .................................. kg
U ............................. tonnes
V .................................. kN
Alternative values:
D ................................... kN
D ................................ kN
S .................................. kg
U ............................. tonnes
V .................................. kN
9.3. For Class A mechanical coupling devices or components, including towing brackets:
Maximum permissible vehicle mass as declared by the vehicle manufacturer's: .................... kg
Distribution of maximum permissible vehicle mass between the axles: .......................................
Vehicle manufacturer's maximum permissible towable trailer mass: ....................................... kg
Vehicle manufacturer's maximum permissible static mass on coupling ball: ........................... kg
Maximum mass:
Maximum mass of the vehicle, with bodywork, in running order, including coolant, oils, fuel,
tools and spare wheel (if supplied) but not including driver: .................................................... kg
Loading condition under which the tow ball height of a mechanical coupling device fitted to
Category M vehicles is to be measured – see Paragraph 2 of Annex 7, Appendix 1:
......................................................................................................................................................
9.4. For Class B coupling heads, is the coupling head intended to be fitted to an unbraked O
trailer: ........................................................................................................................... Yes/No
10. Instructions for the attachment of the coupling device or component type to the vehicle and
photographs or drawings of the mounting points (see Annex 2, Appendix 1) given by the
vehicle manufacturer: ...................................................................................................................
11. Information on the fitting of any special reinforcing brackets or plates or spacing
components necessary for the attachment of the coupling device or component (see Annex 2,
Appendix 1): ..................................................................................................................................
12. Additional information where the use of the coupling device or component is restricted to
special types of vehicles – see Annex 5, Paragraph 3.4.:
......................................................................................................................................................
13. For Class K hook type couplings, details of the drawbar eyes suitable for use with the
particular hook type: .....................................................................................................................

ANNEX 2
COMMUNICATION
(Maximum format: A4 (210 x 297mm) )
issued by:
Name of administration
.............................................
.............................................
.............................................
concerning:
APPROVAL GRANTED
APPROVAL EXTENDED
APPROVAL REFUSED
APPROVAL WITHDRAWN
PRODUCTION DEFINITIVELY DISCONTINUED
of a vehicle type with regard to the fitting of a mechanical coupling device or component pursuant to
Regulation No. 55
Approval No. ...................
Extension No.....................
1. Trade name or mark of vehicle: ....................................................................................................
2. Vehicle type: .................................................................................................................................
3. Manufacturer's name and address: ..............................................................................................
......................................................................................................................................................
4. If applicable, name and address of the manufacturer's representative: .......................................
......................................................................................................................................................
5. Vehicle category, for example, M , N : ......................................................................................

ANNEX 2 – APPENDIX 1
LIST OF INSTALLATION DATA FOR A MECHANICAL COUPLING DEVICE
OR A COMPONENT DESIGNED FOR A SPECIFIC VEHICLE TYPE
1. DESCRIPTION OF THE VEHICLE TYPE:
1.1. Trade name or mark of the vehicle;
1.2. Models or trade names of vehicles constituting the vehicle type, if available.
2. MASSES OF THE TOWING AND TOWED VEHICLES:
2.1. Maximum permissible masses of the towing and towed vehicles;
2.2. The distribution of the maximum permissible mass of the towing vehicle between the axles;
2.3. The maximum permissible vertical loading to be imposed on the coupling ball/hook of the
towing vehicle;
2.4. The loading condition at which the height of the tow ball of M Category vehicles is to be
measured – see Paragraph 2. of Annex 7, Appendix 1.
3. SPECIFICATION OF FIXING POINTS:
3.1. Details and/or drawings of the installation mounting points for the device or component and of
any additional reinforcing plates, support brackets and so on, necessary for reliable
attachment of the mechanical coupling device or component to the towing vehicle;
3.2. The vehicle manufacturer shall specify:
(a)
(b)
The number and location of the fixing points of the coupling device on the motor
vehicle;
The maximum permissible overhang of the coupling point;
(c) The height of the coupling point above the road surface as specified in Annex 7,
Paragraph 1.1.1. and the height of the coupling point in relation to the fixing points of
the coupling.

ANNEX 3
EXAMPLE OF AN ARRANGEMENT OF THE APPROVAL MARK
a = 8mm minimum
The mechanical coupling device or component or vehicle bearing the approval mark shown above is a
device or component approved in the Netherlands (E4), under Approval Number 2439, meeting the
requirements of the 01 series of amendments to this Regulation.
Note:
The approval number and additional symbols shall be placed close to the circle and either
above or below the Letter "E", or to the left or right of that letter. The digits of the approval
number shall be on the same side of the Letter "E" and face in the same direction. The use of
Roman numerals as approval numbers should be avoided so as to prevent any confusion with
other symbols.

ANNEX 5
REQUIREMENTS FOR MECHANICAL COUPLING DEVICES OR COMPONENTS
1. COUPLING BALLS AND TOWING BRACKETS
The requirements stated in Paragraphs 1.1. to 1.5. of this Annex are applicable to all coupling
balls and towing brackets of Class A. Paragraph 1.6. details additional requirements which
shall be fulfilled by standard 50mm diameter coupling balls with flange type bolted fixings.
1.1. Coupling balls of Class A shall conform to Figure 2 in external shape and external
dimensions.
Figure 2
Coupling Ball of Class A

Figure 3
Dimensions of Standard Flange Type Ball Couplings of Class A50-1
(see Table 2)
Figure 4
Dimensions of Standard Flange Type Ball Couplings of Class A50-2 to A50-5
(see Table 2)

2.2. Coupling heads shall be able to satisfy the tests laid down in Annex 6, Paragraph 3.2.
2.3. Any additional device (e.g. braking, stabiliser, etc.) shall not have any adverse effect on the
mechanical connection.
2.4. When not attached to the vehicle, horizontal rotation of the coupling head shall be at least 90°
to each side of the centre line of the coupling ball and mounting described in Paragraph 1 of
this Annex. Simultaneously, there shall be an angle of free vertical movement 20° above and
below the horizontal. Also, in conjunction with the horizontal angle of rotation of 90° it shall be
possible for there to be 25° of roll in both directions about the horizontal axis. The following
articulation shall be possible at all angles of horizontal rotation:
(a) Vertical pitch ±15° with axial roll ±25°
(b) Axial roll ±10° with vertical pitch ±20°
3. DRAWBAR COUPLINGS
The requirements of Paragraphs 3.1. to 3.6. of this Annex are applicable to all drawbar
couplings of Class C50. Additional requirements which shall be fulfilled by standard drawbar
couplings of Classes C50-1 to C50-6 are given in Paragraph 3.7 of this Annex.
3.1. Performance requirements - All drawbar couplings shall be able to satisfy the tests stated in
Annex 6, Paragraph 3.3.
3.2. Suitable drawbar eyes - Class C50 drawbar couplings shall be compatible with all Class D50
drawbar eyes and couplings with the specified characteristics.
3.3. Jaw
Class C50 drawbar couplings shall have a jaw which is designed such that the appropriate
drawbar eye is guided into the coupling.
If the jaw, or a part supporting the jaw, can pivot about the vertical axis, it shall establish itself
automatically in the normal position and with the coupling pin open, be effectively restrained
in this position to give satisfactory guidance for the drawbar eye during the coupling
procedure.
If the jaw, or a part supporting the jaw, can pivot about the horizontal transverse axis, the joint
providing the rotation capability shall be restrained in its normal position by a locking
torque. The torque shall be sufficient to prevent a force of 200N acting vertically upwards on
the top of the jaw producing any deflection of the joint from its normal position. The locking
torque shall be greater than that created by operation of the hand lever described in
Paragraph 3.6 of this Annex. It shall be possible to bring the jaw to its normal position
manually. A jaw that pivots about the horizontal transverse axis is only approved for bearing
mass, S, of up to 50kg and a V-value of up to 5kN.
If the jaw, or a part supporting the jaw, is pivoted about the longitudinal axis, the rotation shall
be restrained by a locking torque of at least 100Nm.

3.4.2. ±20° vertically about the transverse axis from the horizontal plane of the vehicle -
see Figure 6.
Figure 6
Vertical Rotation of the Coupled Drawbar Eye
3.4.3. ±25° axial rotation about the longitudinal axis from the horizontal plane of the vehicle –
see Figure 7.
Figure 7
Axial Rotation of the Coupled Drawbar Eye

Figure 8
Dimensions of Standard Drawbar Couplings (mm)
see Table 4

4. DRAWBAR EYES
4.1. General requirements for drawbar eyes of Class D50:
All drawbar eyes of Class D50 shall be able to satisfy the test stated in Annex 6,
Paragraph 3.4.
Class D50 drawbar eyes are intended for use with C50 drawbar couplings. Drawbar eyes
shall not be able to rotate axially (because the respective couplings can rotate).
If Class D50 drawbar eyes are fitted with sleeves, they shall comply with the dimensions
shown in Figure 9 (not permitted for Class D50-C) or Figure 10.
The sleeves shall not be welded into the drawbar eyes. Class D50 drawbar eyes shall have
the dimensions given in Paragraph 4.2. The form of shank for drawbar eyes of Class D50-X is
not specified. but for a distance of 210mm from the centre of the eye the height "h" and the
width "b" shall be within the limits given in Table 6.
Figure 9
Slotted Sleeve for Class D50 Drawbar Eyes

4.2. Special requirements for Class D50 drawbar eyes:
4.2.1. Class D50-A and D50-X drawbar eyes shall have the dimensions illustrated in Figure 11.
Figure 11
Dimensions of Classes D50-A and D50-X Drawbar Eyes,
see Table 6

4.2.3. Classes D50-C and D50-D drawbar eyes shall have the dimensions illustrated in Figure 13.
Figure 13
Dimensions of Classes D50-C and D50-D Drawbar Eyes,
see other dimensions in Figure 11
4.2.4. Classes D50-C and D50-D drawbar eyes shall be fitted with non slotted sleeves shown in
Figure 10.
4.3. Load Values for Standard Drawbar Eyes
Standard drawbar eyes and the means of attachment shall be suitable for, and tested for, the
load values stated in Table 7.

4.4.4. Class L toroidal drawbar eyes shall satisfy the tests given in Annex 6, Paragraph 3.4 and shall
be suitable for the characteristic values given in Table 9.
5. DRAWBARS
Table 8
Dimensions of Class L Toroidal Drawbar Eyes
see Figure 14 (Dimensions in mm)
Class L L L L L Remarks
a 68
+1.6/ -0.0
b 41.2
± 0.8
76.2
± 0.8
41.2
± 0.8
76.2
± 0.8
41.2
± 0.8
76.2
± 0.8
41.2
± 0.8
68
+1.6/ -0.0
41.2
± 0.8
c 70 65 65 65 70 Min
Table 9
Minimum Characteristic Values for Class L Toroidal Drawbar Eyes
Class L L L L L
D kN 30 70 100 130 180
D kN 27 54 70 90 120
S kg 200 700 950 1000 1000
V kN 12 18 25 35 50
5.1. Drawbars of Class E shall satisfy the tests prescribed in Annex 6, Paragraph 3.3.
5.2. In order to provide a connection to the towing vehicle, the drawbars can be fitted either with
coupling heads as in Paragraph 2 or drawbar eyes as in Paragraph 4 of this Annex. The
coupling heads and drawbar eyes can be attached by screwing, bolting or welding.
5.3. Height Adjusting Devices for Hinged Drawbars
5.3.1. Hinged drawbars shall be fitted with devices for adjusting the drawbar to the height of the
coupling device or jaw. These devices shall be designed so that the drawbar can be adjusted
by one person without tools or any other aids.
5.3.2. Height adjusting devices shall be able to adjust the drawbar eyes or ball couplings from the
horizontal above the ground at least 300mm upwards and downwards. Within this range the
drawbar shall be adjustable steplessly, or in maximum steps of 50mm measured at the
drawbar eye or ball coupling.
5.3.3. Height adjusting devices shall not interfere with the easy movement of the drawbar after
coupling.

Table 10
Mounting Dimensions for Standard Drawbar Couplings (mm)
see Figure 15
Class
C50-1
C50-2
C50-3
C50-4
C50-5
C50-6
C50-7
Remarks
e
83
83
120
140
160
160
± 0.5
e
56
56
55
80
100
100
± 0.5
d

55
75
85
95
95
+1.0/-0.5
d
10.5
10.5
15
17
21
21
H13
T

15
20
35
35
35
maximum
F
120
120
165
190
210
210
minimum
G
95
95
100
130
150
150
minimum
L

200
300
400
400
400
minimum
7. FIFTH WHEEL COUPLINGS AND STEERING WEDGES
The requirements of Paragraphs 7.1 to 7.7. below are applicable to all fifth wheel couplings of
Class G50.
Additional requirements which shall be fulfilled by standard coupling devices are given in
Paragraph 7.9.
Steering wedges shall satisfy the requirements listed in Paragraph 7.8.
7.1. Suitable Fifth Wheel Coupling Pins
7.2. Guides
Class G50 fifth wheel couplings shall be designed so that they can be used with Class H50
coupling pins and, together, provide the specified characteristics.
Fifth wheel couplings shall be equipped with a guide which ensures safe and correct
engagement of the coupling pin. The entry width of the guide for standard 50mm diameter
fifth wheel couplings shall be at least 350mm (see Figure 16).
For small, non-standard, fifth wheel couplings of Class G50-X and having a maximum "D"
value of 25kN, the entry width shall be at least 250mm.

Figure 16a
Mounting Holes Tolerances for Class J Mounting Plates for Fifth Wheel Couplings
(see Paragraph 9.1. of this Annex)
Table 11
Dimensions of Standard Fifth Wheel Couplings (mm)
see Figure 16
Class G50-1 G50-2 G50-3 G50-4 G50-5 G50-6
H 140-159 160-179 180-199 200-219 220-239 240-260
7.3. Minimum Articulation of the Fifth Wheel Coupling
With the coupling pin engaged, without the fifth wheel coupling being attached to a vehicle or
mounting plate, but taking into account the effect of the mounting bolts, the coupling shall
permit, simultaneously, the following minimum values of articulation of the coupling pin:
7.3.1. ±90° about the vertical axis (not applicable to fifth wheel couplings with positive steering);
7.3.2. ±12° about the horizontal axis transverse to the direction of travel. This angle does not
necessarily cover off-road use.
7.3.3. Axial rotation about the longitudinal axis of up to ±3° is permitted. However, on a fully
oscillating fifth wheel coupling, this angle may be exceeded, providing that the locking
mechanism enables the restriction of the rotation to ±3° maximum.

7.8. Steering Wedges
7.8.1. The dimensions of steering wedges for the positive steering of semi-trailers shall be as in
Figure 17.
Notes:
Figure 17
Dimensions of Spring-mounted Steering Wedges
7.8.2. The steering wedge shall allow safe and correct coupling and shall be spring-mounted. The
strength of the spring shall be selected so that it is possible to couple an unloaded semi-trailer
and so that, with the semi-trailer fully loaded the steering wedge is firmly in contact with the
flanks of the coupling during use. Uncoupling of the fifth wheel shall be possible with the
semi-trailer both loaded and unloaded.
7.9. Special Requirements for Standard Fifth Wheel Couplings:
7.9.1. The dimensions shall be as shown in Figure 16 and Table 11.
7.9.2. They shall be suitable for, and tested for, a D value of 150kN and a U value of 20t.
7.9.3. Release shall be possible by a hand lever mounted directly on the coupling.
7.9.4. They shall be suitable for the positive steering of semi-trailers by means of steering wedges –
see Paragraph 7.8.

10. HOOK TYPE COUPLINGS
10.1. General Requirements for Class K Hook Type Couplings:
10.1.1. All Class K hook type couplings shall satisfy the tests given in Annex 6, Paragraph 3.5 and
shall be suitable for the characteristic values given in Table 13
10.1.2. Class K hook type couplings shall have the dimensions given in Figure 19 and
Table 12. Class K1 to K4 are non-automatic couplings for use only on trailers not exceeding
3.5t maximum permissible mass and Class KA1 to KA3 are automatic couplings.
Figure 19
Dimensions and Articulation of Class K Hook Type Couplings
10.1.3. A hook type coupling shall only be used with a toroidal drawbar eye and when used with a
Class L toroidal drawbar eye the Class K coupling shall have the degrees of articulation given
in Paragraph 10.2 of this Annex.
10.1.4. A Class K hook type coupling shall be used with a toroidal eye giving a minimum clearance,
or free movement, of 3mm and a maximum clearance of 5mm when new. Suitable drawbar
eyes shall be declared by the coupling manufacturer on the Communication form shown in
Annex 1.

Table 12
Dimensions for Class K Hook Type Couplings
see Figure 19
Class K K K K KA KA KA Remarks
e − 83 83 120 120 140 160 ± 0.5
e − 56 56 55 55 80 100 ± 0.5
e 90 − − − − − − ± 0.5
d 17 10.5 10.5 15 15 17 21 H13
c 3 3 3 3 3 3 3 Min
f 130 175 175 180 180 200 200 Max
g 100 100 100 120 120 140 200 Max
a 45 45 45 45 45 45 45 +1.6/ -0.0
L 120 120 120 120 250 300 300 Max
L 74 74 63 74 90 90 90 Max
L 110 130 130 150 150 200 200 Max
Table 13
Minimum Characteristic Values for Class K Hook Type Couplings
Class
K
K
K
K
KA
KA
KA
D kN
17
20
20
25
70
100
130
D kN


17
20
54
70
90
S kg
120
120
200
250
700
900
1,000
V kN


10
10
18
25
35
11. DEDICATED DRAWBAR TYPE COUPLINGS - CLASS T
11.1. Class T dedicated drawbar type couplings are intended for use on specific vehicle
combinations, for example, car transporters.
These vehicles have special structures and may need particular and unusual location of the
coupling.
11.2. Class T couplings shall be restricted to use with centre axle trailers and this restriction shall
be notified on the Communication form shown in Annex 1.

13. DEVICES FOR REMOTE INDICATION AND REMOTE CONTROL
13.1. Devices for remote indication and remote control are permitted only on automatic drawbar
couplings and automatic fifth wheel couplings.
Devices for remote indication and remote control are permitted only on automatic coupling
devices of Classes C50-X and G50-X.
Devices for remote indication and remote control shall not interfere with the minimum free
movement of the coupled drawbar eye or coupled semi-trailer. They shall be permanently
fitted to the vehicle.
All the devices for remote indication or remote control fall within the scope of testing and
approval of the coupling device together with all parts of the operating devices and
transmission devices.
13.2. Remote Indication
13.2.1. For an automatic coupling procedure, remote indication devices shall indicate the closed and
doubly locked position of the coupling in an optical manner according to
Paragraph 13.2.2. Additionally the open position may be indicated. In this case, the indication
shall be performed as in Paragraph 13.2.3.
The remote indication device shall be automatically activated and reset during every opening
and closing of the coupling.
13.2.2. The change from the open to the closed and doubly locked position shall be indicated by a
green optical signal.
13.2.3. If the open and/or unlocked position is indicated, a red optical signal shall be used.
13.2.4. In the case of indicating the completion of the automatic coupling procedure, the remote
indicator shall ensure that the coupling pin has reached the doubly locked end position.
13.2.5. The appearance of any fault in the remote indication system shall not indicate a closed and
locked position during the coupling procedure if the end position has not been reached.
13.2.6. The disengagement of one of the two locking devices shall cause the green optical signal to
extinguish and the red optical signal (if fitted) to show.
13.2.7. The mechanical indicators fitted directly to the coupling device shall be retained.
13.2.8. In order to avoid distracting the driver during normal driving, there shall be a provision for
switching off the remote indication device but this shall be automatically reactivated when the
coupling is next opened and closed – see Paragraph 12.2.1.
13.2.9. When installed in the vehicle cab, the remote indication devices shall be mounted within the
driver's direct field of vision, and be clearly identified.
When installed on the side of the vehicle, the remote indication devices shall be permanently
and clearly identified.

ANNEX 6
TESTING OF MECHANICAL COUPLING DEVICES OR COMPONENTS
1. GENERAL TESTING REQUIREMENTS
1.1. Samples of coupling devices shall be tested for both strength and function. Physical testing
shall be carried out wherever possible but unless stated otherwise the Type Approval
Authority or Technical Service may waive a physical strength test if the simple design of a
component makes a theoretical check possible. Theoretical checks may be carried out to
determine worst case conditions. In all cases, theoretical checks shall ensure the same
quality of results as with dynamic or static testing. In cases of doubt it is the results of physical
testing that are overriding.
See also Paragraph 4.8 of this Regulation.
1.2. With coupling devices the strength shall be verified by a dynamic test (endurance test). In
certain cases additional static tests may be necessary (see Paragraph 3 of this Annex).
1.3. The dynamic test (except the test according to Paragraph 3.10. of this Annex) shall be
performed with approximately sinusoidal load (alternating and/or pulsating) with a number of
stress cycles appropriate to the material. No cracks or fractures shall occur.
1.4. Only slight permanent deformation is permitted with the static tests prescribed. Unless stated
otherwise the permanent, plastic, deformation after releasing shall not be more than 10% of
the maximum deformation measured during the test. In the case where measurement of
deformation during the test puts the tester at risk then, provided that the same parameter is
checked during other tests, such as the dynamic test, then this part of the static test may be
omitted.
1.5. The loading assumptions in the dynamic tests are based on the horizontal force component in
the longitudinal axis of the vehicle and the vertical force component. Horizontal force
components transverse to the longitudinal axis of the vehicle, and moments, are not taken
into account provided they are of only minor significance. This simplification is not valid for the
test procedure according to Paragraph 3.10. of this Annex.
If the design of the coupling device or its attachment to the vehicle or the attachment of
additional systems (such as stabilisers, close coupling devices, etc.) generate additional
forces or moments, additional tests may be required by the Type Approval Authority or
Technical Service.
The horizontal force component in the longitudinal axis of the vehicle is represented by a
theoretically determined reference force, the D or D value. The vertical force component,
where applicable, is represented by the static vertical bearing load, S, at the point of coupling
and the assumed vertical load, V, or by the static vertical bearing load, U, in the case of fifth
wheel couplings.
1.6. The characteristic values D, D , S, V and U, on which the tests are based and which are
defined in Paragraph 2.11. of this Regulation, shall be taken from the manufacturer’s
information given in the application for type approval – see communication form shown in
Annexes 1 and 2.

3. SPECIFIC TESTING REQUIREMENTS
In case the test procedure according to Paragraph 3.10. of this Annex is used, the
requirements of Paragraphs 3.1.1. to 3.1.6. are not applicable.
3.1. Coupling Balls and Towing Brackets
3.1.1. Mechanical coupling devices with coupling balls may be of the following types:
(a)
(b)
(c)
One-piece coupling balls including devices with non- interchangeable detachable balls
(see Figures 20a and 20b),
Coupling balls, comprising a number of parts which can be dismantled (see
Figures 20c, 20d and 20e),
Towing brackets without ball fitted (see Figure 20f).
a
One piece towing bracket and coupling ball
b
The ball unit on the above may be detachable by
hand without the use of tools, for example, a
bayonet fitting
c
Towing bracket with ball detachable by the use of
tools
d
Towing bracket with detachable ball on an integral
support, for example, a Class A 50
e
Towing bracket with ball detachable by the use of
tools
f
Towing bracket without fitted ball unit
Figure 20
Arrangements of Ball Type Towing Brackets

3.1.6. The test procedure is applicable to the different types of coupling devices (see
Paragraph 3.1.1 of this Annex) as follows:
3.1.6.1. One piece coupling balls including devices with non-interchangeable detachable balls (see
Figures 20a and 20b).
3.1.6.1.1. The strength test for the devices shown in Figures 20a and 20b shall be carried out according
to the requirements of Paragraph 3.1.5;
Note:
The line parallel to the reference line passes through the centre of the highest and
nearest point for mounting the towing bracket to the vehicle – see Annex 6,
Paragraph 3.1.5.
Figure 21
Angles of Application of Test Force
Note: Direction of alternating test force, F , depending on the location of the ball centre
horizontal reference line in relation to the line parallel to this reference line –
see Figure 21
Figure 22
Angles of Application of Test Force

3.1.7. In the case where detachable ball units are retained using fixing arrangements other than
screwed fittings, for example, spring clips, and where the positive mechanical engagement
aspect of the arrangement is not tested during the dynamic test, then the arrangement shall
be subject to a static test applied to the ball or to the positive mechanical engagement
arrangement in an appropriate direction. Where the positive mechanical engagement
arrangement retains the ball unit vertically, the static test shall be to apply an upwards vertical
force to the ball equivalent to the "D" value. Where the positive mechanical engagement
arrangement retains the ball unit by means of a transverse horizontal design, the static test
shall be to apply a force in this direction equivalent to 0.25D. There shall not be any failure of
the positive mechanical engagement device or any distortion likely to have an adverse effect
on its function.
3.1.8. The attachment points for the secondary coupling referred to in Annex 5, Paragraph 1.5 shall
withstand a horizontal static force equivalent to 2D with a maximum of 15kN. Where there is a
separate attachment point for a breakaway cable this shall withstand a horizontal static force
equivalent to D.
3.2. Coupling Heads
3.2.1. The basic test is an endurance test using an alternating test force followed by a static test
(lifting test) on the same test sample.
3.2.2. The dynamic test shall be performed with a Class A coupling ball of appropriate strength. On
the test rig the coupling ball and coupling head shall be arranged as instructed by the
manufacturer and orientated in a way corresponding to the relative positions in normal
use. There should be no possibility of extra forces in addition to the test force acting on the
specimen. The test force shall be applied along a line passing through the centre of the ball
and inclined downwards to the rear at 15° (see Figure 23). An endurance test must be
performed on a test specimen with the following test force:
F = ± 0.6D
Where the maximum permissible static vertical mass, S, exceeds 120 D, then the angle of
test shall be increased to 20°.
Figure 23
Dynamic Test

The following test forces shall be applied:
Table 14
Test Forces
Test force
Mean Value (kN)
Amplitude (kN)
Horizontal force

3.6.2. For drawbars for full trailers with free movement in the vertical plane, in addition to the
endurance test or theoretical verification of strength, the resistance to buckling shall be
verified either by a theoretical calculation with a design force of 3.0 × D or by a buckling test
with a force of 3.0 × D. The permissible stresses in the case of calculation shall be in
accordance with Paragraph 5.3. of ISO 7641/1:1983.
3.6.3. In the case of steered axles, the resistance to bending shall be verified by theoretical
calculations or by a bending test. A horizontal, lateral static force shall be applied in the centre
of the coupling point. The magnitude of this force shall be chosen so that a moment of
0.6 × Av × g (kNm) is exerted about the front axle centre. The permissible stresses shall be in
accordance with Paragraph 5.3. of ISO 7641/1:1983.
3.7. Fifth Wheel Couplings
3.7.1. The basic strength tests are a dynamic test and a static test (lifting test). Fifth wheel couplings
intended for the positive steering of semi-trailers shall be subject to an additional static test
(bending test). For the purpose of the tests the fifth wheel coupling shall be equipped with all
the fixings needed to attach it to the vehicle. The method of mounting shall be identical to that
employed on the vehicle itself. It is not permissible to use a calculation method as an
alternative to physical testing.
3.7.2. Static Tests
3.7.2.1. Standard fifth wheel couplings designed for a steering wedge or similar device for the positive
steering of semi-trailers (see Paragraph 2.7 of this Regulation) shall be tested for adequate
strength by means of a static bending test within the working range of the steering device with
the simultaneous application of fifth wheel load. The maximum permitted imposed vertical
load, U, for the fifth wheel shall be applied vertically to the coupling in its operating position by
means of a rigid plate of sufficient size to cover the coupling completely.
The resultant of the applied load shall pass through the centre of the horizontal joint of the
fifth wheel coupling.
Simultaneously, a horizontal lateral force, representing the force needed for positive steering
of the semi-trailer, shall be applied to the flanks of the guide for the coupling pin. The
magnitude of this force and the direction in which it acts shall be chosen so that a moment of
0.75m × D is exerted about the centre of the coupling pin by means of a force acting on a
lever arm 0.5m ± 0.1m long. Permanent, plastic deformation up to 0.5% of all nominal
dimensions is permitted. There shall not be any cracking.

3.7.3.2. In the case of fifth wheel couplings intended for the positive steering of semi-trailers the
following forces shall be used:
Horizontal: F = ± 0.675 D
Vertical: F and F as in Paragraph 3.7.3.1.
The lines of action of the forces are as given in Paragraph 3.7.3.1.
3.7.3.3. For the dynamic test of fifth wheel couplings, a suitable lubricating material shall be placed
between the coupling plate and the trailer plate so that the maximum coefficient of friction,
μ ≤ 0.15.
3.8. Mounting Plates for Fifth Wheel Couplings
The dynamic test for fifth wheel couplings described in Paragraph 3.7.3. and the static tests
described in Paragraph 3.7.2. shall also be applied to mounting plates. With mounting plates,
it is sufficient to perform the lifting test on one side only. The test shall be based on the
maximum designated installation height for the coupling, the maximum designated width and
the minimum designated length of the mounting plate design. It is not necessary to carry out
this test if the mounting plate in question is identical to one which has already undergone this
test except that it is narrower and/or longer and the total height is lower. It is not permissible
to use a calculation method as an alternative to physical testing.
3.9. Fifth Wheel Coupling Pins of Semi-trailers
3.9.1. A dynamic test with alternating stress shall be performed on a sample mounted on a test
rig. The testing of the coupling pin shall not be combined with the testing of the fifth wheel
coupling. The test shall be conducted so that the force is also applied to the fixings needed for
attaching the coupling pin to the semi-trailer. It is not permissible to use a calculation method
as an alternative to physical testing.
3.9.2.
A dynamic test with an alternating horizontal force of F
= ± 0.6 D shall be applied to the
coupling pin in the operating position.
The line of action of the force shall pass through the centre of the smallest diameter of the
cylindrical part of the coupling pin having a diameter of 50.8mm for Class H50 (see Annex 5,
Figure 18).
3.10. Alternative Endurance Test for Coupling Balls and Towing Brackets with a
D-value ≤14kN.
Alternatively to the test procedure described in Paragraph 3.1., coupling balls and towing
brackets with a D-value ≤ 14kN can be tested under the following conditions.
3.10.1. Introduction
The endurance test described below consists of a multi-axial test with 3 load directions, with
simultaneously introduced forces, defined maximum amplitudes and fatigue equivalences
(load intensity values, according to the definition given below).

3.10.2.2. Required LIVs and maximum amplitudes
The following coordinate system has to be considered:
x direction: longitudinal direction/opposite of driving direction
y direction: to the right considering the driving direction
z direction: vertical upwards
The load time history can then be expressed following the intermediate directions based on
the main directions (x, y, z) considering the following equations (α = 45; α' = 35.2):
F (t) = F (t) × cos(α) + F (t) × sin(α)
F (t) = F (t) × cos(α) + F (t) × sin(α)
F (t) = F (t) × cos(α) + F (t) × sin(α)
F
F
F
(t) = F (t) × cos(α') + F (t) × sin(α')
(t) = F (t) × cos(α') - F (t) × sin(α')
(t) = F (t) × cos(α') - F (t) × sin(α')
The LIVs expressed in each direction (also combined directions) are calculated respectively
as the sum of the ratio n /N for all available amplitude levels defined in the adequate direction.
In order to demonstrate the minimum fatigue life of the device to be type-approved, the
endurance test has to achieve at least the following LIVs:
LIV (1kN ≤D ≤7kN)
LIV (7kN LIV 0.0212 0.0212
LIV
linear regression between:
D=1 kN: 7.026 e ; D=7kN: 1.4052 e
1.4052 e
LIV 1.1519 e 1.1519 e
LIV
linear regression between:
D=1 kN: 6.2617 e ; D=7kN: 4.9884 e
4.9884 e
LIV 9.1802 e 9.1802 e
LIV
linear regression between:
D=1kN: 7.4988 e ; D=7kN: 4.2919 e
LIV
linear regression between:
D=1kN: 4.5456 e ; D=7kN: 3.9478 e
LIV
linear regression between:
D=1kN: 5.1977 e ; D=7kN: 4.3325 e
LIV
linear regression between:
D=1kN: 4.5204 e ; D=7kN: 2.9687 e
4.2919 e
3.9478 e
4.3325 e
2.9687 e

3.10.4. Failure Criteria
In addition to the criteria given in Paragraph 4.1. of this Regulation verified by liquid
penetration verification, the coupling device shall be deemed to have failed the test, if:
(a)
(b)
(c)
(d)
Any visible plastic deformation is detected;
Any functionality and safety of the coupling is effected (e.g. safe connection of the
trailer, maximum play);
Any torque loss of the bolts exceeding 30% of the nominal torque measured in the
closing direction;
A coupling device with detachable part cannot be detached and attached for at least
3 times. For the first detachment, one impact is permitted.

Figure 25(a)
Clearance Space for, and Height of, Coupling Ball - Side View

1.2. Attachment of Coupling Heads or Toroidal Drawbar Eyes.
1.2.1. Class B coupling heads are permitted for trailers of maximum mass up to and including 3.5t.
With the trailer horizontal and carrying the maximum permitted axle load, coupling heads or
toroidal drawbar eyes shall be fitted so that the centre line of the spherical area into which the
ball fits is 430 ± 35mm above the horizontal plane on which the wheels of the trailer rest.
In the case of caravans and goods trailers, the horizontal position is regarded as when the
floor or loading surface is horizontal. In the case of trailers without such a reference surface
(e.g. boat trailers or similar) the trailer manufacturer shall give an appropriate reference line
defining the horizontal position. The height requirement shall apply only to trailers intended to
be attached to vehicles mentioned in Paragraph 1.1.1. of this Annex. In all cases the
horizontal position shall be determined to within ±1°.
1.2.2. It shall be possible to operate the coupling heads/toroidal drawbar eyes safely within the free
space of the coupling ball/hook coupling given in Figures 25a and 25b, up to angles of
α = 25° and β = 60°.
1.2.3. The design of the drawbar including the coupling head/toroidal drawbar eyes for use on O
and O centre axle trailers shall be such as to prevent the coupling head/toroidal drawbar
eyes from digging into the ground in the event of separation from the main coupling.
1.3. Attachment of Drawbar Couplings and Mounting Blocks
1.3.1. Mounting Dimensions for Standard Drawbar Couplings:
In the case of types of standard drawbar couplings the mounting dimensions on the vehicle
given in Figure 15 and Table 10 of Annex 5 shall be met.
1.3.2. Need for Remote Controlled Couplings
If one or more of the following requirements regarding easy and safe operation
(Paragraph 1.3.3.), accessibility (Paragraph 1.3.5.) or clearance for the hand lever
(Paragraph 1.3.6.) cannot be met, a coupling with a remote control device as described in
Annex 5, Paragraph 12.3. shall be used.

1.3.6. Clearance for the Hand Lever
In order to permit safe operation of drawbar couplings there shall be adequate free space
around the hand lever.
The clearance illustrated in Figure 26 is regarded as sufficient.
If different types of standard drawbar couplings are intended to be fitted to the vehicle, the
clearance shall be such that the conditions are also satisfied for the largest size of coupling of
the appropriate class given in Annex 5, Paragraph 3.
Figure 26
Hand Lever Clearance
The clearance dimensions are also applicable as appropriate for drawbar couplings having
hand levers pointing downwards or of a different design.
The clearance shall also be maintained within the specified minimum angle for coupling up
and uncoupling given in Paragraph 1.3.4. of this Annex.
1.3.7. Clearance for Free Movement of Drawbar Coupling
The drawbar coupling attached to the vehicle shall have a minimum clear gap of 10mm from
every other part of the vehicle taking into account all possible geometrical positions given in
Annex 5, Paragraph 3.
If different types of standard drawbar couplings are intended to be fitted to the vehicle type,
the clearance shall be such that the conditions are also satisfied for the largest possible
coupling of the appropriate class stated in Annex 5, Paragraph 3.

ANNEX 7 - APPENDIX 1
LOADING CONDITIONS FOR THE MEASUREMENT OF COUPLING BALL HEIGHT
1. The height shall be as specified in Annex 7, Paragraph 1.1.1.
2. In the case of M category vehicles the vehicle mass at which this height shall be measured
shall be declared by the vehicle manufacturer and shall be given in the Communication form
(Annex 2). The mass shall be either the maximum permissible mass, distributed between the
axles as declared by the vehicle manufacturer or the mass given by loading the vehicle in
accordance with Paragraph 2.1. of this Appendix.
2.1. The maximum figure for the mass in running order as declared by the towing vehicle
manufacturer (see Item 6. of the Communication form, Annex 2); plus
2.1.1. Two masses, each of 68kg, positioned in the outer seating position of each row of seats, with
the seats in the rearmost adjustable position for normal driving and travel, and with the
masses located:
2.1.1.1. For original equipment coupling devices and components submitted for approval by the
vehicle manufacturer, approximately at a point located at 100mm in front of the "R" point for
adjustable seats and 50mm in front of the "R" point for other seats, the "R" point being
determined according to Regulation No. 14 Paragraph 5.1.1.2.;
or
2.1.1.2. For coupling devices and components submitted for approval by an independent
manufacturer and intended for replacement market fitting, approximately at the position of a
seated person;
2.1.2. In addition, for each mass of 68kg, an additional mass of 7kg allowance for personal luggage
shall be distributed evenly in the luggage area of the vehicle;
3.
In the case of N category vehicles
, the vehicle mass at which this height shall be measured
shall be:
3.1. The maximum permissible mass, distributed between the axles as declared by the towing
vehicle manufacturer (see Item 6. of the Communication form, Annex 2).
Towing Couplings, Forks, Eyes, Fifth Wheels etc.