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.  汽车安全带英文文献和中文翻译(9):http://www.751com.cn/fanyi/lunwen_45011.html