ISO 789-3-2015 pdf free download.Agricultural tractors — Test procedures — Part 3: Turning and clearance diameters
Tracteurs agricoles — Méthodes d’essai — Partie 3: Diamètres de bra quage et de degagement.
5.1.1 Direct measurement
5.1.1.1 Drive the tractor slowly forward while making its sharpest possible right-hand turn, that is, with the steering kept on full right-hand lock, at a speed not exceeding 2 km/h for at least one complete turn, until it is established that the minimum turning circle is being described.
5.1.1.2 Continue to drive the tractor slowly forward on the same lock for a further complete turn, at a speed not exceeding 2 km/h. At short regular intervals around the turn, mark on the ground those points coinciding with the centre of the tire-to-ground contact area of the outermost wheel. Make the marks immediately behind this contact area and determine the position of each mark by visually projecting vertically downwards from the centre of the tire tread width at points on the tire circumference situated as close as possible to the ground.
The marking may be done with or without stopping the tractor. The broken circle formed by the marks on the ground is the turning circle.
5.1.1.3 During the turn described In 5.1.1.2. stop the tractor and drop a plumb-line (32) to the ground from the outermost point of the tractor (that is from the point of the tractor describing the largest circle). Clearly mark the point on the ground beneath the plumb-line: this point lies on the tractor clearance circle.
5.1.1.4 Measure (ii) the diameter of the turning circle (see 5.1.1.2) at a minimum of three places spaced approximately equally around the circle as shown in Figurci. Calculate the average value of the diameter measured and report it as the “minimum turning diameter, right-hand, without brakes”
5.1.1.5 Measure and record the radial distance between the point on the tractor clearance circle (see
5.1.1.3) and the circumference of the tractor turning circle (see 5.1.1.2). Add twice this dimension to the minimum turning diameter and report the result as the “minimum clearance diameter, right-hand, without brakes”
5.1.2 Alternate GPS method
5.1.2.1 Drive the tractor slowly forward while making its sharpest possible right-hand turn, that is, with the steering kept on full right-hand lock, at a speed not exceeding 2 km/h for at least one complete turn, until It Is established that the minimum turning circle Is being described.
5.1.2.2 The diameter of the turning circle shall be calculated as shown in Figure 5 and report It as the “minimum turning diameter, right-hand, without brakes”
5.1.2,3 Measure and record the lateral and longitudinal position from the GPS receiver (i3) to the points on the vehicle most likely to produce the largest clearance circle.ISO 789-3-2015 pdf free download.