BS 4763-1971 Methods for cutting knotted netting to shape (tapering)《结网裁剪成形(锥形)方法》.pdf

1、BRITISH STANDARD BS 4763:1971 Methods for Cutting knotted netting to shape (tapering)BS4763:1971 This British Standard, having been approved by the Ropes andCordage Industry StandardsCommittee, was published under the authorityofthe Executive Boardon 30 July 1971 BSI 12-1999 The following BSI refere

2、nces relate to the work on this standard: Committee reference RCT/8 Draft for comment 70/18858 ISBN 580 06674 6 Co-operating organizations The Ropes and Cordage Industry Standards Committee, under whose supervision this British Standard was prepared, consists of representatives from the following Go

3、vernment department and scientific and industrial organizations: British Railways Board British Tugowners Association Chamber of Shipping of the United Kingdom Cotton Twine Manufacturers Association Council of British Manufacturers of Petroleum Equipment Department of Employment (H.M. Factory Inspec

4、torate) Department of Trade and Industry Dock and Harbour Authorities Association Federation of Soft Fibre Associations* Hard Fibre Cordage Institute* Lloyds Register of Shipping London Master Stevedores Association Ministry of Aviation Supply Ministry of Defence (Air Force Department) Ministry of D

5、efence (Army Department) Ministry of Defence (Navy Department) Synthetic Cordage Manufacturers Association The industrial 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 St

6、andard: British Man-made Fibres Federation British Trawlers Federation Ltd. Department of Agriculture and Fisheries for Scotland Federation of British Trawler Owners Grimsby Net Manufacturers Association Herring Industry Board Ministry of Agriculture, Fisheries and Food Scottish Inshore White Produc

7、ers Association Limited Scottish Trawlers Federation Individual manufacturers Amendments issued since publication Amd. No. Date CommentsBS4763:1971 BSI 12-1999 i Contents Page Co-operating organizations Inside front cover Foreword ii 1 Scope 1 2 Definition 1 3 Types of cut 1 4 Cutting rate 2 5 Metho

8、ds of cutting 4 Appendix A Examples of tapering 6 Figure 1 1 Figure 2 2 Figure 3 2 Figure 4 3 Figure 5 3 Figure 6 4 Figure 7 4 Figure 8 4 Figure 9 4 Figure 10 4 Figure 11 5 Figure 12 5 Figure 13 5 Figure 14 5BS4763:1971 ii BSI 12-1999 Foreword This standard makes reference to the following British S

9、tandards: BS 4440, Glossary of basic terms for fishing nets. Technical Committee 38 Textiles of the International Organization for Standardization (ISO) agreed at its meeting in1960 to a proposal from Germany that a specialist sub-committee be appointed to deal with textile products for fishing nets

10、. This action arose from the increasing interest in standards matters being evinced by the Food and Agriculture Organization of the United Nations and other international bodies concerned with deep sea fishing. It had become evident that there was a need for ISO to examine the subject of fishing net

11、s and produce such Recommendations as were required to co-ordinate, on an international basis, the activities of the fishing industries of the maritime nations. The ISO sub-committee decided that urgent attention should be given to terminology, designation of nets and netting yarns and to methods of

12、 hanging nets and cutting them to shape. The Ropes and Cordage Industry Standards Committee appointed a technical committee to organize the UK contribution to the ISO work and to develop as British Standards such ISO Recommendations as were relevant to the UK industry. This British Standard is based

13、 on ISO/R1532 (with which it is in complete conformity) and is one of a number that will cover aspects being investigated by the ISO sub-committee. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct

14、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 to 7 and a back cover. This standard has been updated (see copyright date) and may have had

15、 amendments incorporated. This will be indicated in the amendment table on the inside front cover.BS4763:1971 BSI 12-1999 1 1 Scope This British Standard defines the different methods of cutting knotted netting to shape by means of straight cuts, the types of cut (N-, T- and Bar-cut) and the rules f

16、or the designation of the cutting rate. (See BS4440 for the definitions of the symbols N and T in netting.) NOTEThe title of the British Standard referred to in this standard is given on pageii. 2 Definition For the purposes of this British Standard, the following definition applies: cutting knotted

17、 netting to shape the cutting from knotted netting of pieces in the shape of trapezia, triangles, parallelograms or other polygons 3 Types of cut Depending on the desired final shape of the netting, tapering cuts shall be made in suitable ways. The various depths of taper are obtained by combining d

18、ifferent lengths of cuts, either along a row of sequential knots (N- or T-cuts respectively) or parallel to a line of sequential mesh bars (B-cuts). (See BS4440 for the definition of the symbols N and T in netting.) The cuts along a row of sequential knots are distinguished by their situation in the

19、 drawing of the net or in the netting that has been hung up for tapering as described in clauses3.1.1 and3.1.2 below. 3.1 K-cuts (knot cuts). Symbol: K. Cuts just beyond the knots. NOTEThe term K-cut may be used instead of the two following terms in cases where the relation to the general course of

20、the netting yarn is insignificant. 3.1.1 N-cut (vertical cut). A cut at right angles to the general course of the netting yarn just beyond the knots; symbol: N. Figure 1 BS4763:1971 2 BSI 12-1999 3.1.2 T-cut (horizontal cut). A cut parallel to the general course of the netting yarn just beyond the k

21、nots; symbol: T. 3.2 Bar-cut. A cut parallel to a line of sequential mesh bars, each from adjacent meshes, and severing one or more bars; symbol: B. 4 Cutting rate 4.1 Definition of cutting rate. To obtain a desired shape and area of netting by tapering, the sequence of N-cuts and B-cuts, N-cuts and

22、 T-cuts or T-cuts and B-cuts shall be such that each cut of one type is the same length as the preceding cut of that type, and the alternation shall proceed in a rhythmical way. This rhythmical alternation of the various types of cuts is called the cutting rate. 4.2 Designation of the cutting rate.

23、The cutting rate is determined by the lengths of consecutive sections of N- or T-cuts and B-cuts. The lengths of the various cuts are indicated as follows: 1) for N- and T-cuts by the number of consecutive meshes cut; 2) for a B-cut by the number of consecutive bars severed along the cutting edge, n

24、ot counting the bars on the preceding knot. Figure 2 Figure 3 BS4763:1971 BSI 12-1999 3 To describe the cutting rate for tapering netting, the number and the type of each cut are indicated, giving first N- or T-cuts, then B-cuts. The following combinations are used for cutting netting to shape: N- a

25、nd B-cuts T- and B-cuts N- and T-cuts Exceptions are cutting rates where any of the named types of cutting is used alone. For these the following symbols are valid: AB = all bars cut AN = all cuts entirely in N-direction (at right angles to the general course of the netting yarn) AT = all cuts entir

26、ely in T-direction (parallel to the general course of the netting yarn) 4.3 Examples of the designation of the cutting rate 4.3.1 Example 1. 1N2B means the rhythmical alternation of one N-cut and two B-cuts. 4.3.2 Example 2. 1T2B means the rhythmical alternation of one T-cut and two B-cuts. Figure 4

27、 Figure 5 BS4763:1971 4 BSI 12-1999 4.3.3 Example 3. 1N2T means the rhythmical alternation of one N-cut and two T-cuts. NOTEFurther examples of cutting rates are given inAppendix A. 5 Methods of cutting (tapering) 5.1 By tapering only one edge of the netting, right-angled trapezia or right-angled tr

28、iangles are made. 5.2 By using the same cutting rate in the same direction on two opposite edges of the netting, parallelograms are made. In the case of netting in the shape of a parallelogram, the triangular piece cut off on one side may be joined to the other edge (seeFigure 10). Figure 6 Figure 7

29、 Figure 8 Figure 9 Figure 10 BS4763:1971 BSI 12-1999 5 5.3 Netting in the shape of isosceles trapezia or isosceles triangles The area of such netting may be divided into two right-angled trapezia or triangles respectively, each of these parts being tapered correspondingly in opposite directions. For

30、 triangular shaped netting (seeFigure 12) each of the two halves must be tapered to a point. 5.4 Netting in the shape of asymmetrical trapezia The area of such netting may be divided into one right-angled trapezium and one right-angled triangle respectively, each of these parts being tapered corresp

31、ondingly. NOTEThe desired final shape of netting should be shown by a diagram which will indicate the direction of the cuts. Figure 11 Figure 12 Figure 13 Figure 14 BS4763:1971 6 BSI 12-1999 Appendix A Examples of tapering Taper cuts losing meshes in suspended netting. Cutting into the piece startin

32、g at top tapered piece on leftBS4763:1971 BSI 12-1999 7 Taper cuts gaining meshes in suspended netting. Cutting away from the piece starting at top tapered piece on leftBS 4763:1971 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsib

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