not exceeding 3,5 tonnes at least one ofthe angles α 1 and α 2 is constant in all normal positions ofuse, its value shall be 60 ± 10º.
4.4.3.4. R e a r sea t s a n d spec ia l fro nt or rea r sea t s, vehi cle ca te g o r i e s o th e r t h a n M1
In vehicles ofcategories other than M , in the case of:
— bench seats,
— adjustable seats (front and rear) with an adjusting device as described in item 1.12 with a seatbac k angle ofless than 20º (see Annex III, figure 1), and
— other rear seats, angles α 1 and α 2 may be between 20 and 80º in any normal position ofuse.
Where in the case offront seats ofvehicles with a maximum vehicle mass not
exceeding 3,5 tonnes at least one ofthe angles α 1 and α 2 is constant in all
normal positions ofuse, its value shall be 60 ± 10º.
▼M4
In the case ofseats, other than front seats, ofvehicles in categories M 2 and M3, the angles α 1 and α 2 shall be between 45 and 90 degrees for all normal positions of use.
4.4.3.5. ◄ The distance between the two vertical planes parallel to the
median longitudinal plane ofthe seat and each passing through a different one of two effective lower anchorages L1 and L2 of the same seat belt shall not be less than 350 mm.
The median longitudinal plane ofthe seat shall pass between points L1 and L2and shall be at least 120 mm from those points.
4.4.4. Location of the effective upper belt anchorage
▼M2
4.4.4.1. If a strap guide or similar device is used which affects the location of the effective upper belt anchorage, this location sha ll be determined in a conventional way by considering the position ofthe anchorage when the longitudinal centre line ofthe strap passes through a point J defined successively from point R by the following three segments:
RZ, which is a segment ofthe reference line measured in an upward direction from R and 530 mm long, ZX, which is a segment perpendicular to the median longitudinal plane ofthe vehicle, measured from point Z in the direction of the anchorage and 120 mm long,
XJ which is a segment perpendi cular to the plane defined by
segments RZ and ZX, measured in a forward direction from point X
and 60 mm long.
Point J2 is determined by symmetry with point J1 about the longitudinal vertical plane passi ng through the reference line described in Item 4.1.2 of the manikin positioned in the seat under consideration.
▼M3
Where a two-door configuration is used to provide access to both the front and rear seats and the upper anchorage is fitted to the ‘B’ post, the system must be designed so as not to impede access to or egress from the vehicle.
▼M2
4.4.4.2. The effective upper anchorage must lie below the plane FN, which runs perpendicular to the longitudi nal median plane ofthe seat and makes an angle of65º with the reference line. The angle can be reduced to 60º in the case ofr ear seats. The plane FN must be positioned as to intersect the reference line at a point D such that DR = 315 mm + 1·8 S. However, when S ≤ 200 mm, DR becomes 675 mm.