BS/EN 12733-2018 pdf download.Agricultural and forestry machinery – Pedestrian controlled motor mowers – Safety.
Where necessary the grassland mower may be elastically restrained at the handle to limit horizontal movement during the tests.
6.2.2.2.3 Configuration/attachments
For the tests the grassland mower shall be tested with all guards In place.
6.2.2.2.4Test enclosure and targct” arrangements for tests 6.2.2.3, 6.2.2.4 and 6.2.2.5
6.2.2.2.4.1 The test enclosure required for the thrown object and impact tests shall be constructed generally as shown in Figure 7.
6.2.2.2.4.2 The walls shall consist of eight panel areas, each 900 mm high, perpendicular to the base of the test fixture so as to form an octagon. The test fixture target panel composition shall meet the material specification of Annex F.
In order to facilitate the counting of hits, the panel supports should be designed to allow sliding in and out of at least one target panel.
The targets shall be located perpendicular to a radial line extending (750 ± 50) mm from the blade tip circle. If a target interferes with a part of the grassland mower such as a handle or a wheel the target shall be moved back sufficient to just avoid such interference.
The target shall be divided into elevation zones by horizontal lines as indicated in Figure 7 and described in Annex G. The target in the operator target area of a grassland mower above 900 mm shall consist of a single sheet of Kraft paper rising to a height of 2 000 mm.
6.2.2.2.5 Ambient temperature during the tests shall be not less than 15 °C.
6.2.2.3 Thrown object test
6.2.2.3.lTest equipment
6.2.2.3.1.1 The grassland mower shall be tested in the test enclosure described in 6.2.2.2.4 and shall be placed on coconut matting/plywood base as specified in Annex H.
The operator target area is determined by the intersection of lines extending from centre A of the blade tip circle and tangent to the 1 000 mm diameter operator area (see Figure 8). The centre of the operator area is located 330 mm to the rear of the handles, when against the upper stop, on a line passing from centre NA through the centre of the handgrip part of the handlebar. The target surface between the intersection of the two tangents and the target is the operator target area.
For grassland mowers with adjustable handlebars, the handlebar shall be positioned to the left to locate the left limit of the operator target area and then to the right to locate the corresponding right limit.
The machine shall be constrained in a suitable manner such that the specified position relative to the injection point is maintained throughout the test. The constraint(s) shall not obstruct free passage of the balls from under the machine.
6.2.2.3.1.2 Five hundred 6,35 mm diameter balls of hardened steel 45 HRC minimum, (e.g. balls used as ball bearings) shall be used as projectiles.
6.2.2.3.1.3 An injection point shall be provided at the 12 h position as in Figure 8 and located (25 i 5) mm inside the blade tip circle for Injection of balls.
The injection tube outlets shall be fixed and flush with, or below, the upper surface of the coconut mat and the system shall be so arranged that the balls can be injected with variable velocity.
6.2.2.3.2 Test method
The grassland mower blade shall be adjusted to the lowest attainable Cut height when set on a hard level surface.
The ball injection mechanism shall ensure consistent free rise heights within a range of 100 mm. Adjust the velocity with which the ball is ejected so that the ball rises not less than 40 mm above the surface of the coconut matting and within an angle of 100 of the vertical axis. Then with the grassland mower in place and operating at maximum engine speed allow balls one at a time Into the grassland mower. Increase the velocity of the balls in small increments until each ball is hit by the grassland mower blade.
NOTE This procedure is intended to ensure that the ball rise height is as low as possible consistent with regular blade impact.
Start the test when this minimum velocity is established. Chipped or damaged balls shall be replaced.
During the tests, in the event of excessive hits in a localized area, the target panel shall be repaired or replaced after counting the hits before continuing with the tests. A target panel shall be replaced If hits from previous tests leave holes that cannot be covered by a 40 mm square gummed label. Not more than one thickness of gummed labels (patch) shall be placed over any one area. Balls remaining within the test fixture (on test surface) shall be removed at the option of the tester to minimize ricochet hits.
The test does not require that the machine has to suitable for use after test.
6.2.2.3.3 Test results
Only test balls passing completely through all layers of the target material shall be regarded as hits. Balls that hit the line dividing one elevation zone from the next shall be scored with the target area below that line.
6.2.2.3.4 Test acceptance (pass/fail cntena)
6.2.2.3.4.1 Machines less than or equal to 1 200 mm width of cut.BS/EN 12733-2018 pdf download.
BS/EN 12733-2018 pdf download
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