AS ISO 5353:2020 – Earth-moving machinery, and tractors and machinery for agriculture and forestry —Seat index point.
5 Technical requirements
5.1 DevIce for seat Index point (SIP) determination
The device for determining the SIP shall comply with figure 1 The mass of the device shall be 6 kg t 1 kg. The work surfaces of the device shall be of hardwood (sanded with 200 or finer grit paper or equivalent and polished) or equivalent material with the same performance to provide minimum friction with the muslin cloth in 5.3.1.
5.2 Adjustments when determining the seat index point (SIP)
When the relevant adjustments are a part of the seat and Its suspension, the seat shall be adjusted according to the following sequential steps before determining the SIP.
5.2.1 Seat adIustment
All fore, alt, vertical and angular adjustments shall be placed In their centre position. When no centre position Is possible, the nearest adjustment that will move the SIP device upward or rearward of centre shall he used.
5.2.2 Suspension system
Block the suspension system according to the manufacturer’s instruction. If such instruction is not provided, block the suspension system at the midpoint of its oscillation range.
Non-adjustable suspension shall be blocked in the vertical position attained with the weighted device in place
5.3 Seat index point (SIP) determination
The SIP shall be determined by using the device illustrated in figure 1 and applying the following procedures.
5.3.1 Seat preparation
Allow sufficient time to ensure that the seat reaches a room temperature of 20 C ± 2 °C before starting the measurement procedure.
Place the seat on a level surface.
Seat a 75 kg ± 10 kg person in the seat twice for I mm periods to flex the seat and back cushions. Allow the seat to remain unloaded for a minimum period of5 mm before starting the measurement procedure.
Cover the seat with a single layer of muslin cloth of sufficient size to prevent direct contact and minimize friction between the cushion surfaces and the measurement device. Take care to prevent the cloth from influencing the positioning of the device.
5.3.2 Device placement
Place the SIP device, without additional masses, laterally central on the seat cushion pushing against the back cushion (see figure 2). Ensure that the device Is laterally controlled and level on the seat.
Add masses to bring the total mass of the device from 6 kg ± 1 kg to 26 kg ± 1 kg; the vertical force centre of the added masses shall be 40 mm in front of the SIP mark on the horizontal section of the device (see figure 1).
To obtain a good fit between the seat cushion, the back cushion, and the SIP measuring device. alternately apply and release a horizontal rearward force of approximately 100 N at the location noted in figure 1. and rock the device from side to side.
Add further masses to bring the total mass of the device from 26 kg t 1 kg to 65 kg ± 1 kg such that the vertical force centre of the additional masses is 40 mm in front of the SIP mark on the horizontal section of the device (see figure 1).
NOTE 3 A 75 kg operator approximates the 65 kg weighted device on the seat.
Repeat the alternate loading and releasing, and the rocking of the device, checking to make sure the
device is laterally central and level on the seat.
5.3.3 Measurement
Make measurements on each side of the SIP measuring device at points an equal distance from the central vertical plane (see figure 2). Average the values. Record within ± 1 mm the coordinate dimensions of the SIP from the fixing point on the seat assembly (see figure 3) that is defined by the manufacturer.
Some machines have seats which fulfil multiple functions, usually by rotating the seat. Functions may include using machine etuIpment or operating the machine in travel mode. For these cases, It may not be possible readily to calculate the location of the different SIPs relative to the fixing point. In these cases, repeat 5.2 and 5.3 for each of the positions.
5.4 Report
The test report shall include the following information:
a) reference to this International Standard;
b) a full description of any test conditions or adjustments different from those specified in this International Standard;
c) a drawing or sketch of the seat assembly showing the coordinate dimensions between the fixing point and the SIP (see figure 3 for an example);
d) description of the seat adjustment ranges available relevant to 5.2.