Directive 94/20/EC of the European Parliament and of the Council (repealed)Show full title

7. FIFTH WHEEL COUPLINGS AND STEERING WEDGES

The requirements of Sections 7.1 to 7.9 are applicable to all fifth wheel couplings of Class G 50.

Section 7.10 lists the additional requirements which must be fulfilled by standard coupling devices.

Steering wedges must satisfy the requirments listed in Section 7.9.

7.1. Suitable fifth wheel coupling pins.

Class G 50 fifth wheel couplings must be designed so that they can be used with Class H 50 coupling pins and provide the specified characteristics with them.

7.2. Automatic operation

Fifth wheel couplings must be automatic in operation (see Annex I, Section 2.1.17).

7.3. Guides

Fifth wheel couplings must be equipped with a guide which ensures safe and secure engagement of the coupling pin. The entry width of the guide must be at least 350 mm.

7.4. Minimum free movement of the fifth wheel coupling with the coupling pin engaged (but with the fifth wheel coupling not attached to a mounting plate or vehicle)

With the coupling pin engaged, fifth wheel couplings must permit the following minimum values of rotation of the coupling pin in the travelling position:

7.4.1.

± 90^o about the vertical axis (not applicable to fifth wheel couplings with positive steering) and, simultaneously,

7.4.2.

± 12^o about the horizontal axis transverse to the direction of travel. This angle does not necessarily cover off-road use.

7.4.3.

Rotation about the longitudinal axis of up to ± 3^o is permitted. However, on a fully oscillating fifth wheel coupling, this angle may be exceeded, providing that locking mechanism enables the restriction of the rotation up to ± 3^o.

7.5. Locking devices to prevent uncoupling of fifth wheel couplings

The locking mechanism of the coupling must secure the coupling pin two positive ways; the second locking device may operate on the first. The first locking device must operate automatically at coupling-up. If the second locking device has to be operated by hand it should only be possible to engage it after the first device has been fully engaged. If the second locking device operates automatically, the engagement of both must be indicated visually.

7.6. Operating devices

In the closed position the operating devices must be secured to prevent inadvertent operation.

7.7. Surface finish

The surfaces of the coupling plate and coupling lock must be functionally satisfactory and carefully machined, forged, cast or pressed.

7.8. Load requirements

All fifth wheel couplings must be able to satisfy the tests described in Annex VI, Section 4.6.

7.9. Steering wedges

Coupling of Class G 50-X which are unsuitable for positive steering must be marked appropriately.

7.9.1. The dimensions of steering wedges for the positive steering of semi-trailers must be as in Figure 15.

7.9.2 The steering wedge must allow safe and secure coupling-up. The steering wedge must be spring-mounted. The strength of the spring must be selected so that it is possible to couple up 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 travel. Uncoupling of the fifth wheel must be possible with the semi-trailer both loaded and unloaded.

7.10. Special requirements for standard fifth wheels couplings

7.10.1. Standard fifth wheel couplings must have the dimensions indicated in Figure 14 and Table 7.

7.10.2. Standard fifth wheel couplings must be suitable for and tested for a D-value of 150 kN and a value of U of 20 tonnes.

7.10.3. Release must be possible by a hand lever directly at the coupling.

7.10.4. Standard fifth wheel couplings must be suitable for the positive steering of semi-traiters by means of steering wedges (see Section 7.9).

TABLE 7

Dimensions of standard fifth wheel couplings (mm) (see Figure 14)

	G 50-1	G 50-2	G 50-3	G 50-4	G50-5	G 50-6
H	140 to 159	160 to 179	180 to 199	200 to 219	220 to 239	240 to 260