BS ISO 9518:2018 pdf download

BS ISO 9518:2018 pdf download.Forestry machinery — Portable chain-saws — Kickback test
1 Scope
This document specifies the methodology for determining the kickback potential of gasoline-powered and electric-powered (including battery powered) chain-saws, complete with guide bar and saw-chain. This document has been demonstrated to be an accurate method of measurement for evaluating computed kickback angles and energy associated with chain-saw kickback for electric-powered chain- saws (including battery powered) and gasoline-powered chain-saws with engine capacity up to 80 cm 3 . It is not intended to evaluate chain-saws with an engine capacity of above 80 cm 3 . Furthermore, because of physical size limitations of the kickback machine, it is not intended for testing of units with guide bar cutting length in excess of 63 cm. Modifications to the methodology for determining the kickback potential introduced in this edition are aimed to have a better reproducibility of the results; test results obtained according to the previous methodology still maintain their validity.
4 Test method
4.1 Principles
The flat surface of the test specimen (MDF) is thrust into contact with the moving saw-chain at the tip of a chain-saw guide bar at a specified speed in order to produce a simulated kickback reaction. This takes place under controlled conditions in the kickback machine, which is designed to measure the magnitude of rotary and horizontal energies generated during the resulting kickback reaction. A step-by-step search, covering a range of critical test conditions, determines the peak energy values to be used in calculating the computed kickback angle(s) CKA using the analytical model. This peak value is intended to simulate the most severe conditions reasonably expected to be encountered by typical users. Since there may be some variability, several impacts are made under each set of conditions and the results averaged. NOTE Test parameters such as approach speed, engine speed, shape and type of test materials have been established to permit consistent evaluation of a wide range of cutting attachment and type of power heads and to simulate kickback situations found in actual practice.
4.2.3 Requirements for testing bars and saw-chains
A guide bar with the largest bar nose radius and/or the greatest number of sprocket teeth represents the highest energy configuration and covers all other bars of the same length with a smaller radius. Tests need not be repeated for saw-chains that have been documented to have lower kickback potential than the highest kickback energy saw-chain on equivalent types of chain-saws. At a minimum, testing shall be performed with the largest bar nose radius of the manufacturer’s designated standard guide bars recommended for sale to the end-user. If multiple bar lengths are listed in the operator’s manual, the longest, shortest, and one other length shall be tested. If the kickback test results for each of these lengths are less than 35° CKA, all other lengths shall be accepted. If any guide bar exceeds 35° CKA, all bar lengths shall be tested.