Commission Regulation (EC) No 631/2009Show full title

1. Lower Legform impactor U.K.

1.1. The lower legform impactor shall consist of two foam-covered rigid segments, representing femur (upper leg) and tibia (lower leg), joined by a deformable, simulated knee joint. The overall length of the impactor shall be 926 ± 5 mm and comply with Figure 1. U.K.

The length of the femur and tibia shall be 432 mm and 494 mm from the centre of the knee respectively.

The centre of gravity of the femur and tibia shall be 217 ± 10 mm and 233 ± 10 mm from the centre of the knee respectively.

Brackets, pulleys, etc. attached to the impactor for the purpose of launching it, may extend the dimensions shown in Figure 1, with the exception of the location of the centre of gravity.

1.2. The diameter of the femur and tibia shall be 70 ± 1 mm and both shall be covered by foam ‘flesh’ and skin. The foam flesh shall be 25 mm thick Confor™ foam type CF-45 or equivalent. The skin shall be made of neoprene foam, faced with 0,5 mm thick nylon cloth both sides, with an overall thickness of 6 mm. U.K.

1.3. The mass of the femur and tibia shall be 8,6 ± 0,1 kg and 4,8 ± 0,1 kg respectively, and the total mass of the impactor shall be 13,4 ± 0,2 kg. U.K.

1.4. The moment of inertia of the femur and tibia, about a horizontal axis through the respective centre of gravity and perpendicular to the direction of impact, shall be 0,127 ± 0,010 kgm² and 0,120 ± 0,010 kgm² respectively. U.K.

1.5. Transducers shall be fitted to measure knee bending angle and knee shearing displacement. A uniaxial accelerometer shall be mounted on the non-impacted side of the tibia, 66 ± 5 mm below centre of the knee, with its sensitive axis in the direction of impact. U.K.

1.6. A damper shall be fitted to the shear displacement system and may be mounted at any point on the rear face of the impactor or internally. The damper properties shall be such that the impactor meets both the static and dynamic shear displacement requirements and prevents excessive vibrations of the shear displacement system. U.K.

1.7. The instrumentation response value channel frequency class (CFC), as defined in ISO 6487:2002, shall be 180 for all transducers. The channel amplitude class (CAC) response values, as defined in ISO 6487:2002, shall be 50° for the knee bending angle, 10 mm for the shearing displacement and 500 g for the acceleration. This does not require that the impactor itself be able to physically bend and shear to these angles and displacements. U.K.

1.8.

The impactor shall meet the certification requirements specified in Section 2 of Appendix I, and shall be fitted with deformable knee elements from the same batch as those used in the certification tests. U.K.

1.8.1. For each test the impactor shall be fitted with new foam cut from one of up to four consecutive sheets of Confor™ foam flesh material, or equivalent, produced from the same batch of manufacture (cut from one block or bun of foam), provided that foam from one of these sheets was used in the dynamic certification test and the individual weights of these sheets are within ±2 % of the weight of the sheet used in the certification test. U.K.

1.8.2. The test impactor or at least the foam flesh shall be stored during a period of at least four hours in a controlled storage area with a stabilised humidity of 35 percent ± 15 percent and a stabilised temperature of 20 ± 4 °C prior to impactor removal for calibration. After removal from the storage the impactor shall not be subjected to conditions other than those existing in the test area. U.K.

1.8.3. Each test shall be completed within two hours of when the impactor to be used is removed from the controlled storage area. U.K.

1.9. The certified impactor may be used for a maximum of 20 impacts before re-certification. With each test new plastically deformable knee elements shall be used. U.K.

The impactor shall also be re-certified if more than one year has elapsed since the previous certification or if any impactor transducer output, in any impact, has exceeded the specified CAC or has reached the mechanical limits of the leg impactor deformation capability.

Figure 1

Lower legform impactor with skin and foam covering