7.6 ADDITIONAL TESTS FOR SAFETY BELTS WITH RETRACTORS

7.6.1 Durability of retractor mechanism

7.6.1.1 The strap must be withdrawn and allowed to retract for the required number of cycles at a rate of not more than 30 cycles per minute. In the case of emergency locking ‘Type 4N Retractors’, a snatch to lock the retractor must be introduced at each fifth cycle.The snatches must occur in equal numbers at each of five different extractors, namely, 90, 80, 75, 70 and 65 per cent of the total length of the strap remaining wound on the retractor. However, where more than 900 mm is provided the above percentages must be related to the final 900 mm of strap which can be withdrawn from the retractor.

7.6.1.2 A suitable apparatus for the tests specified in paragraph 7.6.1.1 above is shown in annex 3 to this Regulation.

7.6.2 Locking of ‘Type 4N Retractors’

7.6.2.1 The retractor must be tested once for locking when the strap has been unwound to full length less 300 ± 3 mm.

7.6.2.1.1 In the case of a retractor actuated by strap movement, the extraction must be in the direction in which it normally occurs when the retractor is installed in a vehicle.

7.6.2.1.2 When retractors are being tested for sensitivity to vehicle deceleration they must be tested at the above extraction along two perpendicular axes, which are horizontal if the retractor is installed in a vehicle as specified by the safety belt manufacturer. When this position is not specified, the testing authority must consult the safety belt manufacturer. One of these axes must be in the direction chosen by the technical service conducting the approval test to give the most adverse conditions with respect to actuation of the locking mechanism.

7.6.2.2 A suitable apparatus for the tests specified in paragraph 7.6.2.1 above is described in annex 4 to this Regulation. The design of any such test apparatus must ensure that the required acceleration is given at an average rate of increase of acceleration at least 25 g[1] per second.

7.6.2.5 To check conformity with the requirements of paragraph 6.2.5.3.1.3 and 6.2.5.3.1.4, the retractor must be mounted on a horizontal table and the table tilted with speed not exceeding 2o per second until locking has occurred. The test must be repeated with tilting in other directions to ensure that the requirements are fulfilled.

7.6.3 Dust resistance

7.6.3.1 The retractor must be positioned in a test chamber as described in annex 5 to this Regulation. It must be mounted in an orientation similar to that in which it is mounted in the vehicle. The test chamber must contain dust as specified in paragraph 7.6.3.2 below. A length of 500 mm of the strap must be extracted from the retractor and kept extracted, except that it must be subjected to ten complete cycles of retraction and withdrawal within one or two minutes after each agitation of the dust. For a period of five hours, the dust must be agitated every twenty minutes for five seconds by compressed air free of oil and moisture at a gauge pressure of 5.5 x 105 ± 0.5 x 105 Pa entering through an orifice, 1.5 ± 0.1 mm in diameter.