ISO 7096 pdf download – Earth-moving machinery – Laboratory evaluation of operator seat vibration.
5.2 Test seat
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 may affect the vibration test result, Before the test, the suspension seats shall be run-in under cordtions stipulated by me manufacturer. If the manufacturer does not state such contions, then the seat shall be runin for 5000 cycles, with measurements at 1 000 cycle IntervalS.
For this purpose, the seat shall be loaded with an inert mass of 75kg and adjusted to the mass In accordance vnth the manufacturers instructions. The seat and suspension shall be mounted on the platlorm of a vibrator, and a sinusoidal input vibration shall be applied to the platform at approximately the suspension natural frequency. This laput 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 ldely 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, on 000 cycles (whichever is less), with the seat being constantly run-In,
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 unatfected by the adjustment for seat height or test person weight, testing shall be performed with the seat adfusted 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 worlIng 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° t 50).
5.3 Test person and posture
The simulated input vibration test shall be performed with two persons. The light person shall have a total mass of
52 kg to 55kg, of which not more than 5 kg may be carried in a bolt around the waist. The heavy person shall have
a total mass of 98kg to 103 kg. of which not more than 8kg may be carried in a belt around the waist.
Each person shall adopt a natural upright position on the seat and maintain this position throughout the test (see Figure 1).
Diflerences in the posture of the test person can cause a 10% difference between test results. For thrs reason, recommended angles of knees and ankles have been specified in Figure 1.
5.4 Input vibration
5.4.1 Simulated input vibration test to evaluate the SEAT factor
This International Standard specifies the mput vibration in nine input spectral classes I EM 1 through EM 9) for earth-moving machinery for the purpose of determining the SEAT factor.
e)type of measuring disc used: semi-rigid, rigid;f)input spectral vibration class;
gvibration transmission to the persons with the simulated input vibration test:
-platform vibration awP12-
-seat disk vibration aws12.
– test person mass, in kilograms,- SEAT factor;
h)calculated transmissibility at the resonance and the resonance frequency;
i)the name of the person responsible for the test;
j)identification of test laboratory;
k)llocation of marking (see clause 7).
ISO 7096 pdf download – Earth-moving machinery – Laboratory evaluation of operator seat vibration
