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1、BRITISH STANDARD BS 4890:1973 Test methods for mechanical joints in conveyor belting UDC 621.867:678.066-419:621.88 Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 07:47:42 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS4890:1973 This British Standard, having been approved by the Rubber Industr
2、y Standards Committee, was published under the authority of the Executive Board on 15 June 1973 BSI 11-1999 The following BSI references relate to the work on this standard: Committee reference RUC/16 Draft for comment 71/55072 ISBN 0 580 07449 8 Co-operating organizations The Rubber Industry Standa
3、rds Committee, under whose supervision this British Standard was prepared, consists of representatives from the following Government departments and scientific and industrial organizations: British Association of Synthetic Rubber Manufacturers British Rubber Manufacturers Association Ltd.* Departmen
4、t of Trade and Industry* Institution of the Rubber Industry Ministry of Aviation Supply Natural Rubber Producers Research Association Rubber and Plastics Research Association of Gt. Britain* Rubber Growers Association Society of Motor Manufacturers and Traders Ltd. Tyre Manufacturers Conference The
5、Government department and scientific and 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 Standard: Association of Solid Woven Belting Manufacturers British Assoc
6、iation of Balata Belting Manufacturers British Man-made Fibres Federation British Plastics Federation Electricity Council, the Central Electricity Generating Board and the Area Boards in England and Wales Engineering Equipment Users Association Federation of Associations of Mining Equipment Manufact
7、urers Institution of Mechanical Engineers Mechanical Handling Engineers Association National Coal Board Amendments issued since publication Amd. No.Date of issueComments Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 07:47:42 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS4890:1973 BSI 11-1999
8、i Contents Page Co-operating organizationsInside front cover Forewordii 1General1 1.1Scope1 1.2Definitions1 2Static tensile strength of joints made with mechanical fasteners1 2.1Method A. Method for joints that can be disconnected1 2.2Method B. Method for joints that cannot be disconnected2 2.3Metho
9、d C. Method for joints that can be disconnected (alternative method for high strength belting)3 3Dynamic life tests for joints made with mechanical fasteners3 3.1Method D. Method for joints in medium strength belting3 Figure 1 Layout for static test6 Figure 2 Single compartment grips7 Figure 3 Doubl
10、e compartment grips7 Figure 4 Testing machine used in method D8 Figure 5 Layout for joint that lacks symmetry about the hinge9 Publications referred to10 Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 07:47:42 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS4890:1973 ii BSI 11-1999 Foreword Thi
11、s British Standard has been prepared under the authority of the Rubber Industry Standards Committee. The methods described are those in use at the Mining Research and Development Establishment of the National Coal Board, Methods C and D having been devised by that Establishment. With the exception o
12、f certain points of detail, Methods A and B are based on those given in ISO/R 1120, “Strength of mechanical fastenings for conveyor belts (Static test method)”, prepared by TC 41, “Pulleys and belts (including vee-belts)” of the International Organization for Standardization (ISO). Method C is inten
13、ded specifically for high strength joints and is designed to overcome the problem of gripping the test pieces at high tension. Method D is intended to enable laboratory comparisons to be made of the joint life in service; it employs 250 mm diameter pulleys that subject the test joint to very severe
14、flexing. It is not suitable for use with belting of the highest strength as the flexing is too severe for a realistic assessment of joint life. A modified method for use under these circumstances is under development and will be published later. A British Standard does not purport to include all the
15、 necessary provisions of a contract. 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,
16、pages 1 to 10, an inside back cover and 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. Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 07:47:42 GMT+00:00 2006,
17、 Uncontrolled Copy, (c) BSI BS4890:1973 BSI 11-19991 1 General 1.1 Scope This British Standard describes static and dynamic methods of test for the evaluation of the strength of joints made in conveyor belting using mechanical fasteners. NOTEThe titles of the British Standards and ISO Recommendation
18、 referred to in this standard are given on the page 10. 1.2 Definitions 1.2.1 pitch the nominal distance between a point on a fastener unit and the corresponding point on the next fastener unit (see Figure 1) 1.2.2 fastened width the number of fastener units inserted in one end of a test piece multi
19、plied by the pitch (see Figure 1) 1.2.3 test tension the tension force in the belt divided by the fastened width 2 Static tensile strength of joints made with mechanical fasteners 2.1 Method A. Method for joints that can be disconnected 2.1.1 Field of application. This method is suitable for determi
20、ning the static tensile strength of joints in conveyor belting made with mechanical fastenings. The method is restricted to joints that can be disconnected. The method is suitable for most types of belting having tensile strengths in the range covered by BS 490 and should be used whenever possible i
21、n preference to Method C. 2.1.2 Apparatus 2.1.2.1 A suitable tensile testing machine complying with the following requirements shall be used. 1) The accuracy of the machine shall be within the limits specified in BS 1610 for Grade A machines. 2) The range of the machine shall be so chosen that the l
22、oads to be measured fall within the upper 90 % of the full-scale deflection. 3) The machine shall have either an autographic force recorder or a maximum force indicator. 4) The rate of traverse of the driven grip shall be 100 5 mm/min. The power shall be sufficient to maintain the rate substantially
23、 constant up to the maximum capacity of the machine. 5) The method of holding the test piece shall be such as to ensure proper alignment of the test pieces in the machine grips, eliminating slip or damage during testing. The use of transverse serrated grips such as are illustrated in Figure 2 has be
24、en found to be suitable. For very thick belts, double compartment grips such as are illustrated in Figure 3 have been found to be suitable. The grips shall be free to move without undue friction and in correct alignment. 2.1.2.2 A steel adaptor plate suited to the dimensions of the type of fastener
25、under test. The adaptor plate shall be such that a half joint can be coupled to it by means of a solid steel rod of suitable diameter (see Figure 1). 2.1.3 Preparation of test pieces 2.1.3.1 The test pieces shall be prepared not less than five days after the date of manufacture of the belting. 2.1.3
26、.2 No test piece shall be cut with its longitudinal edge less than 25 mm from the edge of the belting sample. 2.1.3.3 Three rectangular test pieces shall be prepared from the full thickness of belting. The length of the test piece shall be 150 10 mm plus the gripped length and shall be parallel to t
27、he longitudinal direction of the belting. The width of the test piece shall be 25 mm plus the fastened width (see 2.1.3.4) and shall be parallel to the transverse direction of the belt. Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 07:47:42 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS4890:
28、1973 2 BSI 11-1999 NOTEThe dimensional requirements given differ in detail from those given in ISO/R 1120; the exposed length is precisely defined as 150 mm instead of 100 mm minimum. In addition, the method of defining the test piece width differs from the one standard width of 150 mm given in ISO/
29、R 1120; this has been changed to standardize the stress concentration on the outer fastener units. 2.1.3.4 A number of fastener units shall be inserted into one end of each test piece in such a way that they are disposed symmetrically about the longitudinal centre line. The number of fastener units
30、in each test piece shall be such that the fastened width is as near to 100 mm as possible. NOTEIn the preparation of test pieces good craft practice in belt jointing should be observed and careful attention should be paid to the instructions of the fastener manufacturers. In particular, attention is
31、 drawn to the need for the sheared end of the belting to be cleanly cut and perpendicular to the edge of the belting and for fastening grips to be inserted at the recommended distance from the sheared end. 2.1.4 Conditioning of the test pieces. The test pieces shall be conditioned for three days imm
32、ediately prior to testing, at a temperature of 20 2 C and a relative humidity of 65 5 %. In cases of dispute the conditioning period may be increased to a maximum of 14 days. 2.1.5 Procedure 2.1.5.1 The test piece shall be placed in the grip of the tensile testing machine and the joint shall be coup
33、led to the adaptor plate as shown in Figure 1. The length of test piece exposed between the adaptor plate and the grip shall be 150 10 mm. The test piece shall be assembled symmetrically on the centre line of the testing machine. 2.1.5.2 The testing machine shall then be started and the driven jaw t
34、raversed at the specified rate see 2.1.2.1 4) until rupture occurs. The maximum tensile force shall be recorded as the breaking tension. 2.1.5.3 The manner in which rupture of the joint occurs shall be noted. 2.1.5.4 Three tests shall be carried out, one on each of the three test pieces. NOTEThe req
35、uirements in ISO/R 1120 that the tests are made at standard conditions of temperature and humidity have been omitted as they are considered to be unnecessary and impractical. 2.1.5.5 For each test piece the tensile strength of the joint shall be the breaking tension divided by the fastened width. 2.
36、1.6 Test report. The test report shall state: 1) the method of test used (i.e. BS 4890, Method A); 2) the manufacturer and designation of the fastener used; 3) the manufacturer, designation and overall thickness of the conveyor belting; 4) the three values of tensile strength of the joint, together
37、with the average value; 5) the type of failure. 2.2 Method B. Method for joints that cannot be disconnected 2.2.1 Field of application. The method is suitable for determining the static tensile strength of joints in conveyor belting made with mechanical fastenings. The method is suitable for joints
38、that cannot be disconnected and is not to be used for joints that can be disconnected. 2.2.2 Test method. The test shall be carried out and the results shall be reported in accordance with Method A, except where modified by the following clauses. 2.2.3 Test pieces 2.2.3.1 Six rectangular test pieces
39、 shall be prepared in accordance with 2.1.3.1, 2.1.3.2 and 2.1.3.3 of Method A. 2.2.3.2 The test pieces shall be jointed end-to-end in pairs by means of fasteners under test to form three test assemblies. The number of fastener units used to join each pair of test pieces shall be such that the faste
40、ned width is as near as possible to 100 mm. 2.2.4 Procedure 2.2.4.1 The test assembly shall be mounted symmetrically between the grips of the tensile testing machine. The length of belting exposed between the grips shall be 150 10 mm on each side of the joint. Licensed Copy: sheffieldun sheffieldun,
41、 na, Fri Dec 01 07:47:42 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS4890:1973 BSI 11-19993 2.3 Method C. Method for joints that can be disconnected (alternative method for high strength belting) 2.3.1 Field of application. This method is for determining the static tensile strength of joints in con
42、veyor belting made with mechanical fastenings. The method is restricted to joints that can be disconnected. The method is suitable for joints in high strength belting and is only for use when excessive slipping between the test piece and the grips of the testing machine renders Method A unsuitable.
43、2.3.2 Test method. The test shall be carried out and the tests shall be reported in accordance with Method A, except where modified by the following clauses. 2.3.3 Apparatus. Two steel adaptor plates, suited to the dimensions of the type of fastener under test, shall be used. 2.3.4 Test pieces 2.3.4
44、.1 Three rectangular test pieces shall be prepared from the full thickness of belting. The length of the test pieces shall be 200 mm and shall be parallel to the longitudinal direction of the belt. The width of the test piece shall be 25 mm plus the fastened width (see 2.3.4.2) and shall be parallel
45、 to the transverse direction of the belting. 2.3.4.2 An equal number of fastener units shall be inserted into each end of each test piece in such a way that they are disposed symmetrically about the longitudinal centre line. The number of fastener units in each end of each test piece shall be such t
46、hat the fastened width is as near to 100 mm as possible. 2.3.5 Procedure. Each end of the test piece shall be coupled to an adaptor plate and the assembly then mounted symmetrically on the centre line of the testing machine. 3 Dynamic life tests for joints made with mechanical fasteners 3.1 Method D
47、. Method for joints in medium strength belting 3.1.1 Field of application 3.1.1.1 This method provides a laboratory comparison of the expected life of the joint. 3.1.1.2 The method is suitable for joints made with mechanical fasteners in belting having a nominal tensile strength of up to about 700 k
48、N/m. However, it may be applicable to some belting of higher tensile strength (up to 1 120 kN/m) but in this range conveyor belting may, in some cases, be unduly damaged, or unduly heated, by the severe flexing imposed by the use of small diameter pulleys. In such cases some caution should be exerci
49、zed in interpreting the results and consideration should be given to the adoption of a less severe test method. 3.1.1.3 The normal test tension see 1.2 3) applied to the belt in the test is either 10 % or 12.5 % of the nominal tensile strength of the belting, corresponding, respectively, to the normal service tension and likely overload conditions. However, for investigations into special cases it may be necessary to use higher tensions and, if so, it is recommended that 15 % or 20 % of the nominal tensile strength of the belting be used. 3.1.2 Test