Document ID: chunk:federal_register_of_legislation:F2017C00972:body:0:p19
Version: federal_register_of_legislation:F2017C00972
Segment Type: other
Provision Reference: 
Character Range: 49989–52741

line, is determined.

        6.4.3.5. The distance X, provided for in paragraph 5.11. above, between the tangent Y and the displaced reference line is measured.

        6.4.3.6. To check the effectiveness of the head restraint, the initial load specified in paragraphs 6.4.3.3. and 6.4.3.3.2. is increased to 89 daN unless the breakage of the seat or seat‑back occurs earlier.

        6.5. Determination of the height of the head restraint

        6.5.1. All lines, including the projection of the reference line, shall be drawn in the vertical median plane of the seat or seating position concerned, the intersection of such plane with the seat determining the contour of the head restraint and of the seat‑back (see figure 1 of annex 4 to this Regulation).

        6.5.2. The manikin described in annex 3 to this Regulation shall be placed in a normal position on the seat.

        6.5.3. The projection of the reference line of the manikin shown in annex 3 to this Regulation is then, in the seat concerned, drawn in the plane specified in paragraph 6.4.3.1. above.

         The tangent S to the top of the head restraint is drawn perpendicular to the reference line.

        6.5.4. The distance "h" from the R point to the tangent S is the height to be taken into consideration in implementing the requirements of paragraph 5.5. above.

6.6. Determination of the width of the head restraint
 (see figure 2 of annex 4 to this Regulation)

        6.6.1. The plane S1, perpendicular to the reference line and situated 65 mm below the tangent S defined in paragraph 6.5.3. above, determines a section in the head restraint bounded by the outline C.

        6.6.2. The width of the head restraint to be taken into consideration in implementing the requirements of paragraph 5.10. above, is the distance "L" measured in the plane S1 between the vertical longitudinal planes P and P'.

        6.6.3. The width of the head restraint shall if necessary also be determined in the plane perpendicular to the reference line 635 mm above the R point of the seat, this distance being measured along the reference line.

        6.7. Determination of distance "a" of head restraint gaps
         (see annex 8 to this Regulation)

        6.7.1. The distance "a" shall be determined for each gap and in relation to the front face of the head restraint, by means of a sphere having a diameter of 165 mm.

        6.7.2. The sphere shall be put into contact with the gap in a point of the gap area which allows the maximum sphere intrusion, considering no load is to be applied.

        6.7.3. The distance between the two points of contact of the sphere with the gap will constitute the distance "a" to be considered for the evaluation of the provisions