BS ISO 7915:2021 pdf download – Forestry machinery — Portable chain-saws — Determination of handle strength
This document specifies a test method and strength requirements for the handles of portable handheld chain-saws for use primarily in forestry and tree-service.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 6531, Machinery for forestry — Portable chain-saws — Vocabulary
ISO 6533, Forestry machinery — Portable chain-saw front hand-guard — Dimensions and clearances
ISO 7914, Forestry machinery — Portable chain-saws — Minimum handle clearance and sizes
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 6531 apply.
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4 Test procedure
4.1 Test temperature
The test temperature shall be (20 ± 5) °C.
4.2 Test performance
The test shall be performed with the test loads specified in 4.3. The load shall be gradually applied until the test load is achieved in such a manner that there is no impact damage. When the load specified in 4.3 is obtained, hold the load for a duration of (4 ± 1) s. The test shall be completed within 1 min.
4.3 Load application
The chain-saw handles shall be subjected to static loads as specified in Table 1, separately applied at both handles grip, in each of the six directions illustrated in Figure 1 or Figure 2 and as described in 4.3.3.
4.3.2 Fixation In each case, the chain-saw shall be fixed rigidly by the guide bar mounting pad and securely clamped to prevent flexing of the fixture greater than 2° when load is applied. The sprocket cover may be installed if needed. Direction X P shall be aligned parallel to the theoretical centreline of the guide bar. A minimum clearance shall be maintained to prevent contact between the fixture and any part of the body of the chain-saw, excluding the bar mounting pad, so that they do not touch each other during the test.
4.3.3 Load application
188.8.131.52 General The load shall be applied to each handle over an area of (70 ± 5) mm in width. A means to apply the loads to the handles shall be designed in such a way as to maintain directional orientation to X P , Y P and Z P through the handle midpoint.
184.108.40.206 Load application to the front handle The load shall be centred on the normal handle grip area at (50 ± 5) mm to the left of X 0 (see ISO 6533). 220.127.116.11 Load application to the rear handle The load shall be centred on the grip area (25 ± 5) mm behind the point where the rear most end of the released throttle trigger enters the rear handle in the X direction, and centred on the handle profile in the Y and Z directions.
4.3.4 Relative load directions The load shall be applied to each handle over an area of (70 ± 5) mm in width. A means to apply the loads to the handles shall be designed in such a way as to maintain directional orientation to X P , Y P and Z P through the handle midpoint within ±5° relative to the guide bar mounting pad, while the load is applied. These directions shall be observed, irrespective of any deformation of the handles or the chain- saw body.
5 Test requirements The chain-saw handles shall not break or crack when tested in accordance with Clause 4. After the test it shall be possible that the operator can hold the machine and stop the engine even in the case of full failure of the vibration isolation system. Before and after the test, the dimensional requirements of ISO 6533 and ISO 7914 shall be complied with.