BS 7398-1991 Specification for hand hacksaw frames《手动弓形锯结构规范》.pdf

1、BRITISH STANDARD BS 7398:1991 Specification for Hand hacksaw framesBS7398:1991 This British Standard, having been prepared under the directionof the Machine, Engineers and Hand Tools Standards Policy Committee, waspublished under the authorityof the Board of BSI andcomes into effect on 28February199

2、1 BSI 11-1999 The following BSI references relate to the work on this standard: Committee reference MTE/15 Draft for comment 89/78529 DC ISBN 0 580 19268 7 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Machine, Engineers and Hand Tools

3、 Standards Policy Committee (MTE/-) to Technical Committee MTE/15, upon which the following bodies were represented: British Coal Corporation British Telecommunications plc Consumer Policy Committee of BSI Electricity Supply Industry in England and Wales Federation of British Engineers Tool Manufact

4、urers Federation of British Hand Tool Manufacturers Handle Manufacturers Association Institute of Carpenters Institute of Trading Standards Administration Institution of Production Engineers Ministry of Defence The following body was also represented in the drafting of the standard, through subcommi

5、ttees and panels: Building Employers Confederation Amendments issued since publication Amd. No. Date CommentsBS7398:1991 BSI 11-1999 i Contents Page Committees responsible Inside front cover Foreword ii 1 Scope 1 2 Definitions 1 3 Hand hacksaw frames 1 4 Miniature hand hacksaw frames 4 5 Finish 4 6

6、Marking 5 Appendix A Performance tests for hand hacksaw frames 6 Appendix B Performance tests for miniature hand hacksaw frames 7 Appendix C Restrictions on the use of materials for hacksaw frames for use underground and in other potentially dangerous atmospheres 8 Appendix D Safe usage of hacksaws

7、8 Figure 1 Typical hand hacksaw frame 2 Figure 2 Typical designs of miniature hand hacksaw frames 3 Figure 3 Test rig for hand hacksaw frames 6 Figure 4 Test rig for miniature hand hacksaw frames 7 Figure 5 Tensile test rig for miniature hand hacksaw frames 8 Publication(s) referred to Inside back c

8、overBS7398:1991 ii BSI 11-1999 Foreword This British Standard has been prepared under the direction of the Machine, Engineers and Hand Tool Standards Policy Committee. It takes into account the specific requirements of the Ministry of Defence and of the British Coal Corporation. Performance tests ar

9、e given for both hand hacksaw and miniature hand hacksaw frames. A British Standard does not purport to include all the 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

10、from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to8, 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 amendmen

11、t table on the inside front cover.BS7398:1991 BSI 11-1999 1 1 Scope This British Standard specifies requirements for the design, dimensions, and performance of hand hacksaw frames to take blades of nominal length300mm complying with BS1919 and of miniature hand hacksaw frames to take blades of nomin

12、al length146mm complying with BS6271. NOTE 1Materials are at the discretion of the manufacturer provided that design and performance criteria are met. Normally the working parts are in steel and the handles in either die cast alloy, plastic injection mouldings or shaped wood. NOTE 2Restrictions on t

13、he use of materials for use underground and in other potentially explosive atmospheres are given in Appendix C. NOTE 3The titles of the publications referred to in this standard are given on the inside back cover. 2 Definitions For the purposes of this British Standard the following definitions appl

14、y. 2.1 hacksaw frames frames designed to take hacksaw blades of nominal length300mm NOTETypical hacksaw frames are shown in Figure 1 which also identifies important parts. 2.2 throat depth the distance between the toothed edge of the hacksaw blade and the lower edge of the bow of the frame (see Figu

15、re 1 and Figure 2 for hacksaw frames and miniature hacksaw frames respectively) 2.3 tension pieces those components which link the frame to the blade and through which the tensioning force is applied (see Figure 1) 2.4 pin hole the hole at each end of the blade by means of which the blade is held an

16、d tensioned when inserted into a hand hacksaw frame (see Figure 1) 2.5 frame 1) of hacksaw frames. That component which incorporates a handle and tensioning pieces into which the blade is fitted (see Figure 1). 2) Of miniature hacksaw frames. That component which incorporates a handle and blade anch

17、orage slots (see Figure 2). 2.6 blade retaining pin the pin of the tensioning pieces which enters the pin hole of the blade thus enabling blade location and via which the tension is applied via the tensioning mechanism (see Figure 1) 2.7 handle the piece by which the frame is gripped and through whi

18、ch the major cutting forces are applied (seeFigure 1 and Figure 2 for hacksaw frames and miniature hacksaw frames respectively) 2.8 miniature hacksaw frames frames designed to take miniature hacksaw blades of nominal length146mm NOTETypical frames are illustrated in Figure 2 which also identifies im

19、portant parts. 2.9 blade anchorage slots/blade retainers the means by which the blade pins are secured to the frame for tensioning (see Figure 2) 2.10 blade tensioning the means by which the miniature hacksaw blade is tensioned in the frame (see Figure 2) 2.11 blade pin the pin at each end of the mi

20、niature hacksaw blade by means of which it is held and tensioned in use 3 Hand hacksaw frames NOTEThis clause applies to hand hacksaw frames for use with a hand hacksaw blade of nominal length300mm as specified in BS1919:1983. 3.1 Design 3.1.1 The frame shall provide a secure location for the blade

21、parallel to the centre line axis of the frame. The tension pieces shall provide for this alignment along the whole length of the blade thus avoiding blade twist. 3.1.2 The handle shall provide a comfortable grip and isolate the hand from the throat area of the frame. 3.1.3 The frame shall provide a

22、minimum tension of450N to the blade achieved within the elastic limit of the frame. 3.1.4 There shall be no rotation of the tension pieces when the blade is loaded to minimum tension. 3.1.5 The frame shall be protected against corrosion and rusting.BS7398:1991 2 BSI 11-1999 NOTEVariations in design

23、and means of tensioning are illustrated. Figure 1 Typical hand hacksaw frameBS7398:1991 BSI 11-1999 3 Figure 2 Typical designs of miniature hand hacksaw framesBS7398:1991 4 BSI 11-1999 3.1.6 Provision shall be made for the retention of all of the components in the case of blade failure or removal. N

24、OTEThe following additional design features may be included. a) Additional blade location, e.g.at90 to the plane of the frame. b) Provision for the acceptance of blade lengths other than300mm, e.g.250mm. c) Provision for the acceptance of sawing wires (e.g.tension files and rodsaws). 3.2 Form, dimen

25、sions and tolerances 3.2.1 The frame shall accept a hand hacksaw blade as specified in BS1919:1983. 3.2.2 The frame shall have a minimum throat depth of90mm. 3.2.3 The handle shall provide a minimum unimpeded grip length of85mm. 3.3 Performance 3.3.1 General When tested in accordance with Appendix A

26、 the criteria given in3.3.2 to3.3.5 shall be met. 3.3.2 Tension When the frame has been tensioned in accordance with the manufacturers instructions either by screw, cam or levers the frame shall subject the blade to a minimum load of450N and still function within its elastic limit. 3.3.3 Lateral def

27、lection When the frame has been tensioned to exert a minimum load of450N on the blade, the lateral deflection of the frame shall not exceed3mm. 3.3.4 Tensioning after deformation After4mm of permanent creep deformation has occurred (a reduction in the distance between the blade retaining pins) the f

28、rame shall still be capable of applying a minimum load to the blade of450N and shall still comply with3.3.3. 3.3.5 Creep When the frame has been tensioned at ambient temperature to exert a minimum load of450N on the blade, the permanent deformation of the frame by creep shall not exceed0.1mm per1000

29、h. 4 Miniature hand hacksaw frames NOTEThis clause applies to frames for use with a miniature hacksaw of nominal length146mm as specified in BS6271:1982. 4.1 Design Miniature hacksaw frames shall be of one of the following designs. a) type A, with integral tension A simple structure consisting of a

30、single wire component bent to form a frame. The distance between the ends of the frame is of sufficient dimension to allow a blade to be mounted between slots/blade retainers at each end of the wire frame which locate the pins of the blade. The tensioning of the blade is created by the elastic defor

31、mation of the frame on insertion of the blade. b) type B, with tensioning device This type of frame is a smaller version of a hand hacksaw frame which consists of separate handle and frame and where the tension can be provided by screw or cam action. NOTEType A and type B miniature hand hacksaw fram

32、es are shown in Figure 2. 4.2 Form, dimensions and tolerances 4.2.1 The frame shall accept a miniature hacksaw blade as specified in BS6271:1982. 4.2.2 Throat depth of the frame shall be50mm minimum and the blade shall be held within10 of the plane of the frame NOTEThe frame may also accommodate saw

33、ing wires (e.g.tension files and rodsaws). 4.3 Performance When tested in accordance with Appendix B the following criteria shall be met. a) The frame shall be capable of applying a minimum tension to the blade of200N. b) The frame shall not creep at a rate in excess of0.05mm per1000h when loaded to

34、200N. 5 Finish 5.1 Plating When the frame is protected from corrosion by nickel or chromium plating, it shall meet the requirements of BS1224. When the frame is protected from corrosion by zinc plating, it shall meet the requirements of BS1706. 5.2 Painting Where paints are employed for protection p

35、urposes, the minimum thickness of coating shall be75m.BS7398:1991 BSI 11-1999 5 5.3 Elimination of defects The fully assembled hacksaw or miniature hacksaw frame shall be neatly finished and free from burrs, sharp edges and other defects detrimental to the user. 6 Marking Each frame shall be legibly

36、 marked with the manufacturers name or trademark and the number of this British Standard, i.e.BS7398 1) . NOTEIt is recommended that packaging used for the initial supply of hand hacksaw frames and miniature hand hacksaw frames should include safety notes based on Appendix D. 1) Marking BS7398 on or

37、 in relation to a product represents a manufacturers declaration of conformity, i.e.a claim by or on behalf of the manufacturer that the product meets the requirements of the standard. The accuracy of the claim is therefore solely the responsibility of the person making the claim. Such a declaration

38、 is not to be confused with third party certification of conformity, which may also be desirable.BS7398:1991 6 BSI 11-1999 Appendix A Performance tests for hand hacksaw frames A.1 Principle The performance of a frame is assessed by its ability to apply a minimum amount of tension to a blade, to reta

39、in that tension with time and to be capable of repeated tensioning operations. A.2 Description of apparatus The apparatus shown in Figure 3 may be used for conducting the tension performance test on adjustable and fixed hacksaw frames. NOTEThe letters used to denote positions and apparatus in this c

40、lause correspond to those in Figure 3. Positions C1 and C2 on the fixed bar allow the test to be adapted for250mm and300mm frame sizes. It is essential that the fixed and moving steel bar sections be of sufficient strength so as to avoid deformation when the maximum load is applied at position M. Th

41、e apparatus used in this test consists of a fixed steel bar, E, and a moving notched bar, D, of40mm 15mm section held together pivotally by a steel pin at point C2 or C1. The distance between the pivot point and A and the pivot point and Q is50mm. Further notches are at intervals of25mm to M. NOTETh

42、e letters used in this figure are explained inA.2. Figure 3 Test rig for hand hacksaw framesBS7398:1991 BSI 11-1999 7 The whole arrangement is supported within a rigid steel frame. A and B are the centre line positions of the blade location pins. The distance between A and B is adjusted by using piv

43、ot positions C1 or C2 to accept250mm or300mm size frames. By placing a weight between positions M and Q various loads can be applied to the frame. Each notched position represents a load factor. The factor is1 when the weight is placed at position Q and is increased by0.5 increments to a maximum of5

44、 when the weight is placed at position M. A.3 Test procedure A.3.1 Position the frame with the blade retaining pins secured at A and B under no load conditions. Adjust the tension mechanism of the frame to bring bar D into the horizontal position. Note the position of the tensioning mechanism (zero

45、position). A.3.2 Apply a load of450N (i.e.by applying a weight of9.179kg at position M). Adjust the tension mechanism to return bar D to the horizontal. Measure the lateral deflection of the frame. A.3.3 Check that the amount of further available movement of the tension mechanism for repeated tensio

46、ning to450N is4mm, i.e.the allowance for permanent creep deformation (see3.3.4). A.3.4 Release the load, reposition the tensioning mechanism to zero position and check that the frame has suffered no permanent deformation, i.e.the frame operates within its elastic limit (see3.3.2). A.3.5 For creep te

47、sting load the frame as described inA.3.2 and record movement against time. Check that the permanent deformation of the frame by creep does not exceed that given in3.3.5. Appendix B Performance tests for miniature hand hacksaw frames B.1 Principle The performance of a frame is assessed by its abilit

48、y to apply a minimum amount of tension to a blade and to retain that ability over a finite time period. B.2 Description of apparatus The apparatus shown in Figure 4 or Figure 5 may be used for conducting the performance tests on miniature hand hacksaw frames. B.3 Method B.3.1 Minimum tension Measure

49、 the frame length between the blade retainers with the frame without a blade fitted. Measure again with a blade fitted, and on the adjustable tension type at full tension. The difference between these two measurements is the maximum frame compression. Place an empty frame into the test rig (see Figure 4 and Figure 5), apply a small load,2kg, to remove slack then apply further loads until the frame is compressed to the maximum frame compression. The load required to achieve this compression shall be at least20kg. NOTEA load of20kg is equivalent to a