1、BRITISH STANDARD BS 7747:1994 ISO 8380:1993 Forestry machinery Portable brush cutters and grass trimmers Cutting attachment guard strengthBS7747:1994 This British Standard, having been prepared under the directionof the Agricultural Machinery and Implements Standards Policy Committee, waspublished u
2、nder the authorityof the Standards Boardand comes into effect on 15March 1994 BSI 08-1999 The following BSI references relate to the work on this standard: Committee reference AGE/29 Draft for comment 92/74801 DC ISBN 0 580 22861 4 Committees responsible for this British Standard The preparation of
3、this British Standard was entrusted by the Agricultural Machinery and Implements Standards Policy Committee (AGE/-) to Technical Committee AGE/29, upon which the following bodies were represented: Agricultural Engineers Association Arboricultural Association British Agricultural and Garden Machinery
4、 Association Consumers Association Department of Trade and Industry Forestry Commission Health and Safety Executive Hire Association Europe National Farmers Union Coopted members Amendments issued since publication Amd. No. Date CommentsBS7747:1994 BSI 08-1999 i Contents Page Committees responsible
5、Inside front cover National foreword ii 1 Scope 1 2 Normative reference 1 3 Test requirements 1 4 Test procedure 1 Annex A (informative) Bibliography 3 Figure 1 Test of cutting attachment guard 2 List of references Inside back coverBS7747:1994 ii BSI 08-1999 National foreword This British Standard h
6、as been prepared under the direction of the Agricultural Machinery and Implements Standards Policy Committee. It is identical with ISO8380:1993 Forestry machinery Portable brush-cutters and grass-trimmers Cutting attachment guard strength, published by the International Organization for Standardizat
7、ion (ISO). The Technical Committee has reviewed the provisions of ISO7918, to which normative reference is made in the text, and has decided that they are acceptable for use in conjunction with this standard. A British Standard does not purport to include all the necessary provisions of a contract.
8、Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages1 to4, an inside back cover and
9、a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.BS7747:1994 BSI 08-1999 1 1 Scope This International Standard specifies a test method and the corresponding strength req
10、uirements for cutting attachment guards of portable hand-held combustion engine brush-cutters, for use primarily in forestry, and grass-trimmers, to test their safety in practical use. This ensures safety for the operator being protected from thrown objects and unintentional contacts with the cuttin
11、g attachment. Another aspect of safety when designing a cutting attachment guard is its dimensions: required dimensions are given in ISO7918. NOTE 1The present edition is ISO7918:1985and covers only circular saw-blade guards to brush-saws, but it is anticipated that the new edition will cover cuttin
12、g attachment guard dimensions for portable brush-cutters, brush-saws and grass-trimmers. This International Standard does not apply to cutting attachment guards for lawn-trimmers, which are dealt with in ISO105181. 2 Normative reference The following standard contains provisions which, through refer
13、ence in this text, constitute provisions of this International Standard. At the time of publication, the edition indicated was valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the mo
14、st recent edition of the standard indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO7918:1985, Forestry machinery Portable brush-saws Circular saw-blade guard Dimensions. 3 Test requirements When tested in accordance with clause4, the cutting a
15、ttachment guard shall not break or crack. The dimensions shall comply with the specification in ISO7918before and after the test. 4 Test procedure 4.1 The cutting attachment shall be removed prior to the test. The test shall be carried out at a guard temperature of + 40 C 2 C, and for brush-cutter g
16、uards only, at 25 C 3 C. It is not necessary to heat up or cool down the whole brush-cutter. The brush-cutter shall be mounted on a swivel bracket as close to the powerhead as possible, with the cutting attachment guard downwards (see Figure 1). 4.2 The impact on the cutting attachment guard is gene
17、rated by a total of50blows at each temperature (see4.1) from a steel hammer, suspended on a pendulum length of700 mm 5 mm. The pendulum arm shall be as light as possible. The weight of the hammer shall correspond to a potential energy of the total pendulum system of25J 0,5 J with the hammer raised t
18、o a height in accordance with 4.2.1 and 4.2.2. The hammer shall have a diameter of approximately 85mm and the edges of the impact plane rounded to a radius of maximum5mm. 4.2.1 The hammer shall be raised to a height of1000mm 10mm above the guard and allowed to fall so that it strikes the cutting att
19、achment guard rear edge see Figure 1a). There shall be25 such blows on the rear edge at each temperature (see4.1). 4.2.2 The hammer shall be raised to a height of1000mm 10mm above the guard and allowed to fall so that it strikes the guard from the side where the cutting attachment rotates towards th
20、e guard see Figure 1b). There shall be25such blows from the side at each temperature (see4.1).BS7747:1994 2 BSI 08-1999 Figure 1 Test of cutting attachment guardBS7747:1994 BSI 08-1999 3 Annex A (informative) Bibliography 1 ISO10518:1991, Powered walk-behind and hand-held lawn trimmers and lawn edge
21、 trimmers Mechanical safety requirements and test methods.4 blankBS7747:1994 BSI 08-1999 List of references See national foreword.BS 7747:1994 ISO 8380:1993 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing BritishS
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