BS EN ISO 7096:2020 pdf download – Earth-moving machinery – Laboratory evaluation of operator seat vibration 5.3 Test seat 5.3.1 General The operator seat for the test shall be representative of series-produced models, with regard to construction, static and vibration characteristics and other features which can affect the vibration test result. 5.3.2 Run-in Before the test, the suspension seats shall be run-in under conditions stipulated by the manufacturer. If the manufacturer does not state such conditions, then the seat shall be run-in for 5 000 cycles, with measurements at 1 000 cycle intervals. For this purpose, the seat shall be loaded with an inert mass of 75 kg and adjusted to the mass in accordance with the manufacturer’s instructions. The seat and suspension shall be mounted on the platform of a vibrator, and a sinusoidal input vibration shall be applied to the platform at approximately the suspension natural frequency. This input vibration shall have a peak to peak displacement sufficient to cause movement of the seat suspension over approximately 75 % of its stroke. A platform peak to peak displacement of approximately 40 % of the seat suspension stroke is likely to achieve this. Care should be taken to ensure against overheating of the suspension damper during the running-in, for which forced cooling is acceptable. The seat shall be considered to have been run-in if the value for the vertical transmissibility remains within a tolerance of ±5 % when three successive measurements are performed under the condition described above. The time interval between two measurements shall be half an hour, or 1 000 cycles (whichever is less), with the seat being constantly run-in. 5.3.3 Seat adjustment The seat shall be adjusted to the weight of the test person in accordance with the manufacturer’s instructions. With seats where the suspension stroke available is unaffected by the adjustment for seat height or test person weight, testing shall be performed with the seat adjusted to the centre of the stroke. With seats where the suspension stroke available is affected by the adjustment of the seat height or by test person weight, testing shall be performed in the lowest position which provides the full working suspension stroke as specified by the seat manufacturer. When the inclination of the backrest is adjustable, it shall be set approximately upright, inclined slightly backwards (approximately 10° ± 5°). 5.4 Test person and posture The posture of the test...
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