1、BRITISH STANDARD AEROSPACE SERIESCONFIRMEDAPRIL 1998BS 2SP 91-92:1973(SupersedingBS SP 91 and SP 92)IncorporatingAmendment Nos. 1, 2and 3Specification forCarbon steel wormdrive clamps foraircraft*UDC 629.69.14 *Index form of title: CLAMPS, WORM DRIVE, CARBON STEEL, FOR AIRCRAFTLicensedCopy:MissJudiC
2、rimmins,BritishStandardsInstitution,04/12/201215:50,UncontrolledCopy,(c)TheBritishStandardsInstitution201291-92:+A4:2015ICS 49.035BS 2SP 91-92:1973+A4:2015ISBN 978 0 580 81034 3Amendments issued since publicationAmd. No. Date Comments1541 September 19742012 June 19765903 September 1988A4 January 201
3、5 See ForewordThis British Standard, having been approved by the Aerospace Industry Standards Committee, was published under the authority of the Executive Board on 15 May 1973 The British Standards Institution 2015 Published by BSI Standards Limited 2015The following BSI references relate to the wo
4、rk on this standard: Committee reference ACE/14 Drafts for comment 72/33600 DC 13/30273384BS 2SP 91-92:1973 BSI 01-2000 iContentsPageForeword ii1 General requirements 11.1 Scope 11.2 General principles 11.3 Materials 11.4 Range of sizes and overall dimensions 21.5 Band 21.6 Tightening device 21.7 Fi
5、nish 31.8 Operation 31.9 Identification and marking 31.10 Information to be given in drawings for inspection purposes 31.11 Information to be given in drawings and schedules for call-up 42 Inspection and testing 42.1 General 42.2 Inspection of clamps 42.3 Samples for inspection and testing 42.4 Test
6、ing of samples 52.5 Test apparatus 52.6 Tests on band material 52.7 Screw torque 52.8 Ultimate torque load 62.9 Opening test 62.10 Hydraulic pressure test 62.11 Air pressure test 7Figure 1 Details of clamps 1Figure 2 Materials 8Figure 3 Dimensions of bands 9Figure 4 Hydraulic pressure test 10Figure
7、5 Arrangement of test rig for torque testing 10Figure 6 Arrangement of clamps and joints for air pressure test 11Table 1 Dimensions of clamps 2Table 2 Clamp identification 3Table 3 Sample requirements 4Table 4 Screw torque values 6Table 5 Maximum permitted torque values 6Table 6 Hydraulic pressure t
8、est values 7Table 7 Air pressure test values 7Licensed Copy: Miss Judi Crimmins, British Standards Institution, 04/12/2012 15:50, Uncontrolled Copy, (c) The British Standards Institution 2012BS 2SP 91-92:1973ii BSI 01-2000ForewordThese British Standards have been prepared at the request of the Aeros
9、pace Industry to supersede BS SP 91-92, January 1962, to incorporate the amendments issued and to bring the format into line with current practice.The standards specify dimensional requirements of carbon steel worm drive clamps for aircraft to ensure functional interchangeability, and include detail
10、s of hydraulic and pneumatic tests to ensure adequate sealing when the clamps are used on hose connections. Provision is made for clamps with bands having serrations rolled or milled, without perforating the band, and for clamps having pierced serrations which penetrate through the band, each type b
11、eing given a distinctive identification.These standards represent the current thinking at the time of publication in the light of known or published or projected standards for inch based hoses or tubes, with equivalents inserted in order that clamps may be used for metric applications. The standards
12、 may require amendment in line with future developments.Reference is made in this standard to the following specifications.British Standards:BS 970, Wrought steels in the form of blooms, billets, bars and forgings, Part 1: Carbon and carbon manganese steels, including free-cutting steels. BS 1449, S
13、teel plate, sheet and strip. BS F 67, Hose for aviation fuel and engine lubricating oil for aeronautical purposes. Ministry of Defence (Procurement Executive) Specification:DTD 904, Cadmium plating. NOTE The values stated in inch units are to be regarded as the standard. Approximate metric units are
14、 shown alongside in parentheses or adjacent columns.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 from legal obl
15、igations.Summary of pagesThis document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 11 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.
16、Licensed Copy: Miss Judi Crimmins, British Standards Institution, 04/12/2012 15:50, Uncontrolled Copy, (c) The British Standards Institution 2012BS 2SP 91-92:1973+A4:2015i The British Standards Institution 2015Protective finishBS 2SP 91-92:1973+A4:2015ii The British Standards Institution 2015Forewor
17、dPublishing informationBS 2SP 91-92:1973+A4:2015 is published by BSI Standards Limited, under licence from The British Standards Institution, and came into effect on 31 January 2015. It was prepared by Technical Committee ACE/12, Aerospace Fasteners and Fastening. A list of organizations represented
18、 on this committee can be obtained on request to its secretary.SupersessionBS 2SP 91-92:1973+A4:2015 supersedes BS 2SP 91-92:1973 (incorporating Amendments No.1, No.2 and No.3), which is withdrawn.Information about this documentThe standards specify dimensional requirements of carbon steel worm driv
19、e clamps for aircraft to ensure functional interchangeability, and include details of hydraulic and pneumatic tests to ensure adequate sealing when the clamps are used on hose connections. Provision is made for clamps with bands having serrations rolled or milled, without perforating the band, and f
20、or clamps having pierced serrations which penetrate through the band, each type being given a distinctive identification.These standards represent the current thinking at the time of publication in the light of known or published or projected standards for inch based hoses or tubes, with equivalents
21、 inserted in order that clamps may be used for metric applications. NOTE The values stated in inch units are to be regarded as the standard. Approximate metric units are shown alongside in parentheses or adjacent columns.This document makes reference to the following standards:British Standards:BS 9
22、70-1, Wrought steels in the form of blooms, billets, bars and forgings Part 1: Carbon and carbon manganese steels, including free-cutting steels.BS 1449, Steel plate, sheet and strip.BS 2F 67:1980, Aerospace series Specification for Hose for aviation fuel and engine lubricating oil for aeronautical
23、purposes. BS EN 2133, Aerospace series Cadmium plating of steels with specified tensile strength 1 450 MPa, copper, copper alloys and nickel alloys.BS EN 10139, Cold rolled uncoated mild steel narrow strip for cold forming Technical delivery conditions. BS EN ISO/IEC 17025, General requirements for
24、the competence of testing and calibration laboratories.MoD Defence Equipment and Support Standard:Def Stan 03-19, Electro-Deposition of Cadmium The start and finish of text introduced or altered by Amendment No.4 is indicated in the text by tags . Minor editorial changes are not tagged. Previous ame
25、ndments are not indicated.Presentational conventionsThe provisions of this standard are presented in roman (i.e. upright) type. Its requirements are expressed in sentences in which the principal auxiliary verb is “shall”.Commentary, explanation and general informative material is presented in smalle
26、r italic type, and does not constitute a normative element.Contractual and legal considerationsThis 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 cannot confer immunity from leg
27、al obligations.BS 2SP 91-92:1973 BSI 01-2000 11 General requirements1.1 ScopeThese British Standards specify the dimensions, material, finish and test requirements for carbon steel worm drive clamps for aircraft.1.2 General principlesThe clamp shall consist of a band with serrations rolled, milled o
28、r pierced across the longitudinal axis and extending in from one end. A screw with a thread of the same pitch as the serrations shall be retained in a suitable housing attached to the other end of the band, so that when the band is formed as shown inFigure 1 it will engage with the serrations. The l
29、oop so formed shall be capable of being tightened and slackened when the screw is turned, and shall be capable of easy fitment and removal.1.3 Materials1.3.1 The clamps shall be manufactured from the materials specified in Figure 2 and certified as such by the material supplier.1.3.2 The band materi
30、al shall comply with the tests specified in 2.6.Housing depth V = 0.55 in (14 mm) max.Overall width W1= 0.625 in (16 mm) max.Housing width W2= 0.55 in (14 mm) max.Slot depth d = 0.094 in (2.4 mm) max.Slot width s = 0.63 in (1.6 mm) max.Head diameter H = 0.38 in (9.7 mm) max.Figure 1 Details of clamp
31、sLicensed Copy: Miss Judi Crimmins, British Standards Institution, 04/12/2012 15:50, Uncontrolled Copy, (c) The British Standards Institution 2012BS 2SP 91-92:1973 BSI 01-2000 11 General requirements1.1 ScopeThese British Standards specify the dimensions, material, finish and test requirements for c
32、arbon steel worm drive clamps for aircraft.1.2 General principlesThe clamp shall consist of a band with serrations rolled, milled or pierced across the longitudinal axis and extending in from one end. A screw with a thread of the same pitch as the serrations shall be retained in a suitable housing a
33、ttached to the other end of the band, so that when the band is formed as shown inFigure 1 it will engage with the serrations. The loop so formed shall be capable of being tightened and slackened when the screw is turned, and shall be capable of easy fitment and removal.1.3 Materials1.3.1 The clamps
34、shall be manufactured from the materials specified in Figure 2 and certified as such by the material supplier.1.3.2 The band material shall comply with the tests specified in 2.6.Housing depth V = 0.55 in (14 mm) max.Overall width W1= 0.625 in (16 mm) max.Housing width W2= 0.55 in (14 mm) max.Slot d
35、epth d = 0.094 in (2.4 mm) max.Slot width s = 0.63 in (1.6 mm) max.Head diameter H = 0.38 in (9.7 mm) max.Figure 1 Details of clampsLicensed Copy: Miss Judi Crimmins, British Standards Institution, 04/12/2012 15:50, Uncontrolled Copy, (c) The British Standards Institution 2012BS 2SP 91-92:1973+A4:20
36、151 The British Standards Institution 2015CAUTION. BS SP 91 and SP 92 clamps have cadmium as a plating material, which has been restricted and/or banned for use in many countries owing to environmental and health concerns; they should not be used in new product designs. Local officials should be con
37、sulted about any concerns on using cadmium-plated parts.BS 2SP 91-92:19732 BSI 01-2000Table 1 Dimensions of clamps1.4 Range of sizes and overall dimensionsThe range of sizes and overall dimensions of the clamps shall be in accordance with those specified in Figure 1 and Table 1.1.5 Band1.5.1 The ban
38、d shall have suitable provision for attachment of the housing at one end and transverse centrally disposed serrations at the other end, commencing at the end and extending for a length (depending upon the size of clamp) sufficient to enable the clamp to be tightened on the smallest assembly for whic
39、h it is designed.1.5.2 For BS SP 91 clamps, the serrations shall be rolled or milled; they shall not penetrate through the band. The serrations and the metal between them shall be of equal width, and such that the screw forms an adequate key in them when engaged. The dimensions of the band shall con
40、form to those given inFigure 3a.1.5.3 For BS SP 92 clamps the serrations shall be pierced through the band. The serrations and the gaps between them shall be of the form and dimensions shown in Figure 3b, and shall be such that the screw forms an adequate key in them when engaged. The dimensions of
41、the band shall conform to those given in Figure 3b.1.5.4 The internal surface of the band shall be smooth and all surfaces shall be free from burrs, projections and sharp edges.1.6 Tightening device1.6.1 The tightening device shall consist of a cheese head screw permanently retained in a housing fir
42、mly attached to one end of the band.1.6.2 The clamps shall be capable of being tightened or slackened only by means of a screwdriver slot.Clamp sizeWorking range diameter Housing length LengthX Y Zmin. max. max. max.in mm in mm in mm in mmA 0.5 13 0.625 16 0.55 14 1.0 25B 0.5 13 0.75 19 0.55 14 1.0
43、25C 0.625 16 0.875 22 0.785 20 1.0 25D 0.75 19 1.0 25 0.785 20 1.0 25E 0.875 22 1.125 28 0.95 24 1.16 29F 1.0 25 1.375 35 0.95 24 1.16 29G 1.125 28 1.625 41 0.95 24 1.16 29H 1.25 32 1.875 48 1.095 28 1.30 33J 1.5 38 2.125 54 1.095 28 1.30 33K 1.75 44 2.375 60 1.095 28 1.30 33L 2.0 50 2.75 70 1.095 2
44、8 1.30 33M 2.375 60 3.125 80 1.095 28 1.30 33N 2.75 70 3.5 90 1.095 28 1.30 33P 3.25 82 4.0 100 1.095 28 1.30 33Q 3.75 95 4.5 115 1.095 28 1.30 33R 4.125 105 5.0 125 1.095 28 1.30 33NOTE Special sizes larger than the above range shall be designated by the MAXIMUM diameter in 1/10ths in, in increment
45、s of 0.5 in, e.g. 7 in (180 mm) will be Size 070 (see also 2.4.6) and the working diameter range of these larger sizes shall be 1.0 in (25.4 mm).Licensed Copy: Miss Judi Crimmins, British Standards Institution, 04/12/2012 15:50, Uncontrolled Copy, (c) The British Standards Institution 2012BS 2SP 91-
46、92:1973+A4:2015 The British Standards Institution 2015BS 2SP 91-92:1973 BSI 01-2000 31.6.3 The following screw details shall apply.1.6.3.1 The screw shall have a washer or retaining device attached to each end, or to a recess in the screw, to retain and adequately support the head of the screw and t
47、o prevent sideways or axial movement of the screw.1.6.3.2 On clamps having bands with rolled or milled serrations, the screw shall have an 0.3125 in (8 mm) or larger nominal diameter. The thread shall be single start, right hand and of square or ACME type. For sizes A and B the screw may have an 0.2
48、5 in (6 mm) nominal diameter.1.6.3.3 On clamps having bands with pierced serrations the screw shall have an 0.3125 in (8 mm) or larger nominal diameter. The thread shall be single start, right hand and of square or buttress type.1.6.4 The housing shall hold the screw firmly in engagement with the se
49、rrations on the band. The housing shall be of rigid construction and shall not distort permanently when the test load is applied.1.6.5 The housing shall be rigidly and securely attached to the band by riveting, welding and/or mechanical keying. The arrangement shall not permit any quick release device; the only method of releasing or loosening the clamp shall be by turning the screw in a counter-clockwise direction.1.6.6 All parts of the clamps shall be cadmium plated in accordance with the latest issue of Procurement Executive, Minis
