1、BRITISH STANDARD BS 5431:1976 Specification for Bending springs for use with copper tubes for water, gas and sanitation UDC 669.14272.2:621.981.1:669.3462:621.643.24:696BS5431:1976 This British Standard, having been prepared under the directionof the Non-Ferrous Metals Standards Committee, waspublis
2、hed under the authorityof the ExecutiveBoardon 30 November1976 BSI 06-1999 The following BSI references relate to the work on this standard: Committee reference NFE/17 Draft for comment72/44724DC ISBN 0 580 09570 3 Cooperating organizations The Non-Ferrous Metals Standards Committee, under whose sup
3、ervision this British Standard was prepared, consists of representatives from the following Government department and scientific and industrial organizations: Aluminium Federation Association of Bronze and Brass Founders BNF Metals Technology Centre* British Electrical and Allied Manufacturers Assoc
4、iation* British Lead Manufacturers Association British Non-Ferrous Metals Federation* Copper Development Association* Electric Cable Makers Federation Institute of British Foundrymen Institution of Mechanical Engineers* Institution of Mining and Metallurgy Institution of Production Engineers Institu
5、tion of Structural Engineers Lead Development Association Light Metal Founders Association London Metal Exchange Magnesium Industry Council Ministry of Defence* National Brassfoundry Association Non-Ferrous Metal Stockists* Royal Institute of British Architects Society of Motor Manufacturers and Tra
6、ders Limited Tin Research Institute Zinc Development Association Individual manufacturers* The organizations marked with an asterisk in the above list, together with the following, were directly represented on the committee entrusted with the preparation of this British Standard: British Gas Corpora
7、tion Copper Tube Fittings Manufacturers Association Department of the Environment Electricity Supply Industry in England and Wales Engineering Industries Association Institution of Gas Engineers Institution of Heating and Ventilating Engineers National Association of Plumbing, Heating and Mechanical
8、 Services Contractors National Water Council Oil Companies Materials Association Amendments issued since publication Amd. No. Date of issue CommentsBS5431:1976 BSI 06-1999 i Contents Page Cooperating organizations Inside front cover Foreword ii 1 Scope 1 2 References 1 3 Spring material 1 4 Spring d
9、imensions 1 5 Spring properties 1 6 Finish 1 7 Designation and identification 1 8 Protection 1 Figure 1 Internal bending spring 2 Figure 2 External bending spring 3 Table 1 Dimensions of internal bending springs 2 Table 2 Dimensions of external bending springs 2 Table 3 Spring properties and colour
10、codes of internal and external bending springs 3 Publication referred to Inside back coverBS5431:1976 ii BSI 06-1999 Foreword Steel springs are used to support the wall of copper tubes during bending. The majority of copper tube bent by this method is copper tube meeting the requirements of BS2871-1
11、. The publication of the metric revision of BS2871-1 in1971 afforded the opportunity to rationalize the dimensional properties of steel bending springs used for this purpose. The spring sizes, properties and finish specified are intended to ensure that steel bending springs meeting the requirements
12、of this standard are satisfactory under normal conditions of use. A colour code to assist identification of the appropriate springs is also included. An essential feature of internal bending springs is the ease of withdrawal after the bending operation. This is achieved by forming the springs by win
13、ding the material from which they are made, so that on further winding after the bending, they slightly reduce in diameter, thereby permitting ease of withdrawal. Internal and external springs wound in either a right-hand or a left-hand fashion are satisfactory and, since both types currently enjoy
14、wide usage, both are included in this specification. It is hoped that after a period of time it will be possible to standardize whichever method of winding becomes the more widely used. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standa
15、rds 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, pagesi andii, pages1to4, an inside back cover and back cover. This standard
16、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.BS5431:1976 BSI 06-1999 1 1 Scope This British Standard specifies the dimensions, properties and colour code of steel bending springs intended to su
17、pport the wall during bending operations on copper tubes complying with the requirements of BS2871-1:1971, Tables W, X and Y. Dimensions and properties of the springs are specified for sizes of tube up to and including22mm diameter. 2 Reference The title of the standards publication referred to in t
18、his standard is given on the inside back cover. 3 Spring material 3.1 Manufacture. The bending springs shall be made in spring steel of chemical composition and with subsequent heat treatment to meet the requirements of5.1 and5.2. 3.2 Material section. The springs shall be produced from wire having
19、trapezoidal (truncated wedge) cross section with corners having a minimum radius of10% of the nominal size of the wire at the larger end of the section. The smaller end of the section shall have a slight radius in the corners. As an optional alternative, springs may also be produced from wire of squ
20、are section with a radius of10% of the nominal size of the wire on the corners. Sizes of wire (dimension B) shall be in accordance with Table 1 and Table 2. 4 Spring dimensions 4.1 Internal bending springs. Dimensions A, B and C of internal bending springs shall be in accordance with Table 1. An eye
21、 or loop shall be formed at one end, the external diameter of which shall not exceed the maximum diameter of the body of the spring. The spring, which may be wound either right-handed or left-handed, shall be straight and have an overall length of approximately610mm. One end shall be tapered to faci
22、litate its entry into the tube over a length not greater than1“ times the outside diameter of the spring. 4.2 External bending springs. Dimensions A, B, C and D of external bending springs shall be in accordance with Table 2. The spring, which may be wound either right-handed or left-handed, shall b
23、e straight and have an overall length of approximately300mm. At one end, four end coils shall be opened out to diameter D given in Table 2 to facilitate insertion of the tube. 5 Spring properties 5.1 Spring strength. The strength of the spring shall be determined by suspending it vertically by the i
24、nsertion of a plate in the taper portion, and then applying at the eye end the appropriate load given in Table 3 (in the case of external bending springs, two plates will be needed). Under these conditions the spring shall be capable of supporting the test load without exceeding the permissible exte
25、nsion given in Table 3. 5.2 Bend properties. The bend properties of the spring shall be determined by placing it at90 to the longitudinal axis of a mandrel of the appropriate diameter given in Table 3. The spring shall then be wrapped round the mandrel to form one complete turn. After completion of
26、the test, the spring shall be allowed to return to a straight condition and shall show no sign of permanent distortion. 6 Finish The outside diameter of the spring may be lightly ground to ensure a smooth even surface, in which case precautions shall be taken to ensure that the corner radii (see3.2)
27、 are still sufficient to prevent the edges from damaging the tube during bending operations. The surface of the spring in contact with the tube shall be smooth and free from any surface damage marks. 7 Designation and identification The spring shall be designated by the size of the tube with which i
28、t is intended to be used, e.g.10mm,18mm, etc. The springs shall be identified by the appropriate colour code given in Table 3. 8 Protection The springs shall be packed and protected from deterioration during storage. BS5431:1976 2 BSI 06-1999 Table 1 Dimensions of internal bending springs Table 2 Di
29、mensions of external bending springs NOTEValues of dimensions A, B and C are given in Table 1. Figure 1 Internal bending spring For use with copper tube to BS2871-1:1971 Designated spring size Bending spring dimensions Outside diameter A Length B of large side of trapezoidal section or side of squar
30、e section Overall Length C (approx.) Min. Max. Table X mm 12 15 18 22 mm 10.50 13.28 16.06 19.85 mm 10.62 13.40 16.18 19.97 mm 2.0 2.24 2.50 2.80 mm 610 610 610 610 Table Y 12 15 18 22 10.06 12.62 15.62 19.19 10.18 12.74 15.74 19.31 2.0 2.24 2.50 2.80 610 610 610 610 For use with copper tube to BS28
31、71-1:1971 Designated spring size Bending spring dimensions Inside diameter A Outside diameter D of opened-out end coil Length B of large side of trapezoidal section or side of square section Overall length C (approx.) Min. Max. Tables W X and Y mm 6 8 10 mm 6.30 8.30 10.30 mm 6.45 8.45 10.45 mm 14 1
32、7.5 21 mm 1.25 1.50 1.80 mm 300 300 300BS5431:1976 BSI 06-1999 3 Table 3 Spring properties and colour codes of internal and external bending springs NOTEValues of dimensions A, B, C and D are given in Table 2. Figure 2 External bending spring For use with copper tube to BS2871-1-1971 Designated spri
33、ng size Spring properties Colour code Load Extension (max.) Mandrel diameter Table X mm 12 15 18 22 kg 6.8 7.6 8.4 9.1 mm 12 12 12 12 mm 25 25 30 38 Amber Table Y 12 15 18 22 6.8 7.6 8.4 9.1 12 12 12 12 25 25 30 38 White Tables W, X and Y 6 8 10 2.2 3.2 4.5 12 12 12 16 22 22 Amber and white bands4 b
34、lankBS5431:1976 BSI 06-1999 Publication referred to BS2871, Copper and copper alloys. Tubes. BS2871-1, Copper tubes for water, gas and sanitation. BS 5431:1976 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing Briti
35、shStandards. It presents the UK view on standards in Europe and at the international level. It is incorporated by Royal Charter. Revisions BritishStandards are updated by amendment or revision. Users of BritishStandards should make sure that they possess the latest amendments or editions. It is the
36、constant aim of BSI to improve the quality of our products and services. We would be grateful if anyone finding an inaccuracy or ambiguity while using this BritishStandard would inform the Secretary of the technical committee responsible, the identity of which can be found on the inside front cover.
37、 Tel:02089969000. Fax:02089967400. BSI offers members an individual updating service called PLUS which ensures that subscribers automatically receive the latest editions of standards. Buying standards Orders for all BSI, international and foreign standards publications should be addressed to Custome
38、r Services. Tel:02089969001. Fax:02089967001. In response to orders for international standards, it is BSI policy to supply the BSI implementation of those that have been published as BritishStandards, unless otherwise requested. Information on standards BSI provides a wide range of information on n
39、ational, European and international standards through its Library and its Technical Help to Exporters Service. Various BSI electronic information services are also available which give details on all its products and services. Contact the Information Centre. Tel:02089967111. Fax:02089967048. Subscri
40、bing members of BSI are kept up to date with standards developments and receive substantial discounts on the purchase price of standards. For details of these and other benefits contact Membership Administration. Tel:02089967002. Fax:02089967001. Copyright Copyright subsists in all BSI publications.
41、 BSI also holds the copyright, in the UK, of the publications of the international standardization bodies. Except as permitted under the Copyright, Designs and Patents Act 1988 no extract may be reproduced, stored in a retrieval system or transmitted in any form or by any means electronic, photocopy
42、ing, recording or otherwise without prior written permission from BSI. This does not preclude the free use, in the course of implementing the standard, of necessary details such as symbols, and size, type or grade designations. If these details are to be used for any other purpose than implementation then the prior written permission of BSI must be obtained. If permission is granted, the terms may include royalty payments or a licensing agreement. Details and advice can be obtained from the Copyright Manager. Tel:02089967070.
