1、BRITISH STANDARD AEROSPACE SERIES BS 3SP 170-171:2002 Braided rubber cord assemblies for aerospace use ICS 49.035 BS 3SP 170-171:2002 This British Standard, having been prepared under the direction of the Engineering Sector Policy and Strategy Committee, was published under the authority of the Stan
2、dards Policy and Strategy Committee on 27 September 2002 BSI 27 September 2002 The following BSI references relate to work on this British Standard: Committee reference ACE/25 Draft for comment DC 00/706549 ISBN 0 580 40307 6 Committees responsible for this British Standard The preparation of this B
3、ritish Standard was entrusted to Technical Committee ACE/25, Rubber, elastomeric and sealant materials for aerospace purposes, upon which the following bodies were represented: British Hydromechanics Research Group (BHR) British Narrow Fabrics Association (BNFA) British Rubber Manufacturers Associat
4、ion Ltd (BRMA) UK Defence Standardization Society of British Aerospace Companies (SBAC) Amendments issued since publication Amd No. Date CommentsBS 3SP 170-171:2002 BSI 27 September 2002 i Contents Page Committees responsible Inside front cover Foreword ii 1S c o p e 1 2 Normative references 1 3 Met
5、hod of assembly 1 4 Tests on finished assembly 1 5 Identification 2 6 Packaging and storage 2 Bibliography 3 Figure 1 Braided rubber cord assembly 2 Table 1 Test loads 2BS 3SP 170-171:2002 ii BSI 27 September 2002 Foreword This British Standard has been prepared by Technical Committee ACE/25. It sup
6、ersedes BS 2SP 170-171:1985, which is withdrawn. This new edition reverses the precedence of material and plating requirements. This new edition of BS SP 170-171 incorporates technical changes only. It does not reflect a full review or revision of the standard, which will be undertaken in due course
7、. WARNING. This British Standard calls for the use of substances and/or procedures that may be injurious to health if adequate precautions are not taken. It refers only to the technical suitability and does not absolve the user from legal obligations relating to health and safety at any stage. Durin
8、g manufacture and subsequent cutting and handling of materials containing aramid fibre, dust is released into the workroom atmosphere. Some of this dust is in the respirable size range. The Control of Substances Hazardous to Health Regulations 1 require this dust to be controlled, preferably at sour
9、ce, so as to minimize the risk of inhalation so far as is reasonably practicable. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from leg
10、al obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 3 and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued.BS 3SP 170-171:2002 BSI 27 September 2002 1 1 Scope This Briti
11、sh Standard specifies requirements for assemblies for aerospace applications of the following four types of braided rubber cords conforming to BS F 70 and BS F 71 with ferrules and assembly wires conforming to BS SP 168-169 manufactured from stainless steel or cadmium plated steel. BS 3SP 170: heavy
12、 duty cotton covered in accordance with BS F 70; heavy duty aramid fibre covered in accordance with BS F 70/A; BS 3SP 171: light duty cotton covered in accordance with BS F 71; light duty aramid fibre covered in accordance with BS F 71/A. 2 Normative references The following referenced documents are
13、 indispensable for the application 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. BS F 68, Specification for controlled storage of vulcanized rubbers for use in aerospac
14、e applications. BS F 69, Specification for packaging and identification of vulcanized rubber items. BS F 70, Specification for heavy duty braided rubber cord. BS F 71, Specification for light duty braided rubber cord. BS 3SP 168-169:2002, Ferrules and assembly wires for braided rubber cord assemblie
15、s for aerospace use. 3 Method of assembly 3.1 The range of assembly wires shall be as given in BS 3SP 168-169:2001, Table 1. The wire shall be squeezed firmly into position while the cord is stretched at approximately 100 % elongation. Care shall be taken to avoid damage to either the braiding or ru
16、bber threads when elongating the cord or securing the assembly wire. After fixing the assembly wire the cord shall be cut at not less than its own diameter beyond the assembly wire, the ends of the assembly wire shall not butt, but overlap or be left with a gap not exceeding 10 % of the diameter of
17、the cord. 3.2 The ferrule, which shall have been threaded previously on to the cord, shall be pulled tightly over the assembly wire. The cord, after trimming, shall be not more than the equivalent of one ferrule wire diameter above or below the top coil of the ferrule. The ferrule shall not be disto
18、rted by opening out the bottom coil to gain ease of assembly. 3.3 Stainless steel and cadmium plated steel ferrules and assembly wires shall not be mixed on any one assembly. 4 Tests on finished assembly 4.1 Measurement of unstretched length Assemblies shall be measured for length inside the hooks o
19、f the ferrules, as shown in Figure 1, within 24 h of stretching by the method given in 4.2. The measured length shall not differ from the specified length by more than: a) plus the equivalent of half the diameter of the cord used or 1 % of length, whichever is the greater; b) minus the equivalent of
20、 the diameter of the cord used or 2 % of length, whichever is the greater. 4.2 Tests on stretched assembly 4.2.1 Each assembly shall be capable of withstanding the test loads shown in Table 1 after remaining in the test conditions for determination of the mechanical properties of the cord as require
21、d by BS F 70 and BS F 71.BS 3SP 170-171:2002 2 BSI 27 September 2002 4.2.2 Tests shall be applied to at least 25 % of any batch of less than 20 per type manufactured at one time, and larger batches shall be tested at least 5 % per type manufactured at one time. Should any failure occur during such t
22、ests the whole batch shall be tested. The test load shall be applied over a period of at least 3 s. 5 Identification Each assembly shall be identified for ordering purposes by the relevant British Standard number suffixed by a code letter designating the material used for the ferrules and assembly w
23、ires, followed by the nominal cord diameter, followed by the unstretched length expressed to the nearest millimetre. The material of manufacture of the ferrules and assembly wires shall be identified by the letter “S” for stainless steel or “P” for cadmium plated steel (see BS SP 168-169). The outer
24、 braiding shall be identified by the letter “A” for aramid fibre; no suffix letter is required for cotton braid. Examples BS 3SP 171/S/6.5/100 mm BS 3SP 170/P/12.5/A/150 mm 6 Packaging and storage Finished assemblies shall be packaged in accordance with BS F 69 and shall be stored in accordance with
25、 BS F 68. Table 1 Test loads Cord diameter Test load Cord assemblies in accordance with BS 3SP 170 Cord assemblies in accordance with BS 3SP 171 mm N N 3,0 11 4,0 20 5,0 65 31 5,5 40 6,5 130 53 8,0 196 80 9,5 280 114 11,0 152 12,5 480 16,0 800 NOTE During normal operation, the extension of cord asse
26、mblies should not exceed 30 % for cords conforming to BS F 70, and 50 % for cords conforming to BS F 71, of the exposed length of cord as shown in Figure 1. The maximum extension of the assemblies during installation should not exceed 75 % for cords conforming to BS F 70 or 100 % for cords conformin
27、g to BS F 71. Figure 1 Braided rubber cord assemblyBS 3SP 170-171:2002 BSI 27 September 2002 3 Bibliography 1 GREAT BRITAIN. Control of Substances Hazardous to Health Regulations 1994. London: The Stationery Office.BS 3SP 170-171:2002 BSI 389 Chiswick High Road London W4 4AL BSI British Standards In
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