ISO 7096:2000 pdf free.Earth-moving machinery — Laboratory evaluation of operator seat vibration.
The operators of earth-moving machinery are often exposed to a low frequency vibration environment partly caused by the movement of the vehicles over uneven ground and the tasks carried out. The seat constitutes the last stage of suspension before the driver. To be efficient at attenuating the vibration, the suspension seat should be chosen according to the dynamic characteristics of the vehicle. The design of the seat and its suspension are a compromise between the requirements of reducing the effect of vibration and shock on the operator and providing him with stable support so that he can control the machine effectively.
Thus, seat vibration attenuation is a compromise of a number of factors and the selection of seat vibration parameters needs to be taken in context with the other requirements for the seat.
The performance criteria provided in this International Standard have been set in accordance with what is attainable using what is at present the best design practice. They do not necessarily ensure the complete protection of the operator against the effects of vibration and shock. They may be revised in the light of future developments and improvements in suspension design.
The test inputs included in this International Standard are based on a very large number of measurements taken in situ on earth-moving machinery used under severe but typical operating conditions. The test methods are based on ISO 10326-1, which is a general method applicable to seats for different types of vehicles.
1.1 This International Standard specifies, in accordance with SO 103261, a laboratory method for measuring and evaluating the effectiveness of the seat suspension in reducing the vertical whole-body vibration transmitted to the operator of earth-moving machines at frequencies between 1 Hz and 20 Hz. It also specifies acceptance criteria for application to seats on different machines.
1. 2 This International Standard is applicable to operator seats used on earth-moving machines as defined in ISO 6165.
2 Normative references
ISO 2041: 1990, Vibration and shock- Vocabulary.
ISO 2631-1: 1997, Mechanical vibration and shock-Evaluation of human exposure to whole-body vibration – Part1:General requirements.
ISO 6016: 1998, Earth-moving machinery-Methods of measuring the masses of whole machines, their equipment and components.
ISO 6165: 1997, Earth-moving machinery-Basic types-Vocabulary.
ISO 8041: 1990, Human response to vibration-Measuring instrumentation.
ISO 10326-1: 1992, Mechancal vibration-Laboratory method for evaluating vehicle seat vibration – Part 1: Basic requirements.
4 General
4.1 The laboratory-simulated machine vertical vibration, specified as input spectral class, is based on representative measured data from machines in severe but typical working conditions. The input spectral class is a representative envelope for the machines within the class, as measured under severe conditions.
1.2 Two criteria are used for the evaluation of seat:
a)the Seat Effective Amplitude Transmissibility(SEAT) factor according to SO 103261: 1992, 91, but with frequency weighting according to ISO 2631-1;
b)the maximum transmissibility ratio in the damping test according to SO 10326-1: 1992, 9.2.
4.3 The measuring equipment shall be in accordance with ISO 8041(type 1 instrument)and SO 103261: 1992 clauses 4 and 5. The frequency weighting shall include the effects of the band limiting filters, and be in accordan with ISO 2631.
4.4 Safety precautions shall be in accordance with ISO 13090-1
Any compliant end-stops or devices normally fitted to production versions of the seat to be tested to minimise the effect of suspension overtravel shall be in place for the dynamic tests.ISO 7096:2000 pdf free download.