1、BRITISH STANDARD AEROSPACE SERIES CONFIRMED APRIL1998 BS SP 144-147:1971 Incorporating Amendment Nos.1 and2 Specification for Corrosion resisting worm drive clamps for aircraft* UDC 629.7:621.643.44:621.885.6:669.018.8:669.14+669.245 *Index form of title: “Clamps, worm drive, corrosion resisting, fo
2、r aircraft”.BSSP144-147:1971 This BritishStandard, having been approved by the Aerospace Industry Standards Committee, was published under the authorityof the Executive Boardof the Institution on 23April1971 BSI 02-2000 The following BSI references relate to the work on this standard: Committee refe
3、rence ACE/14 Draft for comment69/15786 ISBN 0 580 06601 0 Foreword This BritishStandard has been prepared at the request of the Aerospace Industry to introduce a range of corrosion resisting worm drive clamps to complement the range of normal steel hose clamps given in BS SP91 and BSSP92 which corre
4、spond dimensionally with BS3628, “Hose clips (wormdrive type) for general purpose use”. The standard specifies dimensional requirements to ensure functional interchangeability, and includes details of hydraulic and pneumatic tests to ensure adequate sealing when the clamps are used on hose connectio
5、ns. It makes provision for clamps with bands having serrations rolled or milled without perforating the band, and for clamps with bands having pierced serrations which extend right through the band, each type having a distinctive identification. This standard represents the current thinking at the t
6、ime of publication in the light of known published or projected standards for metric hoses and tubes, and may subsequently require amendment in line with future developments. This standard makes reference to the following BritishStandards: BS1449, Steel plate, sheet and strip Part4: Stainless and he
7、at resisting plate, sheet and strip. BS1554, Rust, acid and heat resisting steel wire. BS3073, Nickel and nickel alloys. Strip. BS3076, Nickel and nickel alloys. Rods. BSF67, Hose for aviation fuel and engine lubricating oil for aeronautical purposes. NOTEThe values stated in metric units are to be
8、regarded as the standard. Approximate imperial units are 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
9、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, pages1 to12 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be in
10、dicated in the amendment table on the inside front cover. Amendments issued since publication Amd. No. Date of issue Comments 887 March1972 1542 September 1974 Indicated by a sideline in the marginBSSP144-147:1971 BSI 02-2000 i Contents Page Foreword Inside front cover 1 General requirements 1.1 Sco
11、pe 1 1.2 General principles 1 1.3 Materials 1 1.4 Range of sizes 1 1.5 Overall dimensions 1 1.6 Band 1 1.7 Tightening device 2 1.8 Finish 2 1.9 Operation 2 1.10 Marking and identification 2 1.11 Information to be given in drawings for inspection purposes 3 1.12 Information to be given in drawings an
12、d schedules, for call-up 3 2 Inspection and testing 2.1 General 3 2.2 Inspection of clamps 3 2.3 Samples for inspection and testing 4 2.4 Testing of samples 4 2.5 Test apparatus 4 2.6 Tests on band material 4 2.7 Screw torque 5 2.8 Ultimate torque load 5 2.9 Opening test 5 2.10 Hydraulic pressure te
13、st 5 2.11 Air pressure test 6 Figure 1 Materials 8 Figure 2 Overall dimensions of clamps 9 Figure 3 Dimensions of bands 10 Figure 4 Hydraulic pressure test 11 Figure 5 Arrangement of test rig for torque testing 11 Figure 6 Arrangement of clamps and joints for air pressure test 12 Table 1 Range of si
14、zes 1 Table 2 Clamp identification 3 Table 3 Sample requirements 4 Table 4 Screw torque values 5 Table 5 Maximum permitted torque values 5 Table 6 Hydraulic pressure test values 6 Table 7 Air pressure test values 7ii blankBSSP144-147:1971 BSI 02-2000 1 1 General requirements 1.1 Scope These BritishS
15、tandards specify the dimensions, material, finish and test requirements for corrosion resisting worm drive clamps for aircraft. 1.2 General principles The clamp shall consist of a band with serrations pierced, milled or rolled across the longitudinal axis and extending in from one end. A screw with
16、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 in Figure 1 it will engage with the serrations. The loop so formed shall be capable of being tightened and slackened when the screw is
17、turned, and shall be capable of easy fitment and removal. 1.3 Materials 1.3.1 The clamps shall be made from the materials specified in Figure 1 and certified as such by the material supplier. 1.3.2 The band material shall comply with the test specified in2.6. 1.4 Range of sizes The range of sizes of
18、 clamps shall be as listed in Table 1. Special sizes larger than this range shall be designated by the maximum diameter in millimetres, e.g.180mm(7in) will be size180 (see also2.4.6), and the working diameter range of these larger sizes shall be25mm(1in). Table 1 Range of sizes 1.5 Overall dimension
19、s The overall dimensions of the clamps shall not exceed those specified in Figure 2. 1.6 Band 1.6.1 The band shall have suitable provision for attachment of the housing at one end and transverse serrations centrally disposed commencing at the other end and extending for a length (dependent upon the
20、size of the clamp) sufficient to enable the clamp to be tightened on to the smallest assembly for which it is designed. Clamp size Working diameter range From Up to and including 013 016 019 022 025 028 035 041 048 054 060 070 080 090 100 115 125 mm 9 13 13 16 19 22 25 28 32 38 44 50 60 70 82 95 105
21、 in 0.375 0.5 0.5 0.625 0.75 0.875 1.0 1.125 1.25 1.5 1.75 2.0 2.375 2.75 3.25 3.75 4.125 mm 13 16 19 22 25 28 35 41 48 54 60 70 80 90 100 115 125 in 0.5 0.625 0.75 0.875 1.0 1.125 1.375 1.625 1.875 2.125 2.375 2.75 3.125 3.5 4.0 4.5 5.0BSSP144-147:1971 2 BSI 02-2000 1.6.2 BS SP144 and BS SP145 requ
22、ire that the serrations shall be rolled or milled. Serrations 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 conform to those given in Figure
23、3a. 1.6.3 BS SP146 and BS SP147 require that the serrations shall be pierced through the band. Serrations and the metal between them shall be of equal width and shall be such that the screw forms an adequate key in them when engaged. The dimensions of the band shall conform to those given in Figure
24、3b. 1.6.4 The internal surface of the band shall be smooth and all surfaces shall be free from burrs, projections or sharp edges. 1.7 Tightening device 1.7.1 The tightening device shall consist of a cheese head screw permanently retained in a housing firmly attached to one end of the band. 1.7.2 The
25、 clamps shall be capable of being tightened or slackened only by a screwdriver slot. 1.7.3 The following screw details shall apply: 1.7.3.1 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
26、to prevent sideways or axial movement of the screw. 1.7.3.2 On clamps having bands with rolled or milled serrations, the screw shall have an8mm(0.312in) nominal or larger diameter. The thread shall be single start, right-hand, and of square or Acme type. For sizes013,016 and019 the screw may have a6
27、mm(0.236in) nominal diameter. 1.7.3.3 On clamps having bands with pierced serrations, the screw shall have an8mm(0.312in) nominal or larger diameter. The thread shall be single start, right-hand, and of square or buttress type. 1.7.4 The housing shall hold the screw firmly in engagement with the ser
28、rations on the band. The housing shall be of rigid construction and shall not distort permanently when the test load is applied. 1.7.5 The housing shall be rigidly and securely attached to the band by riveting, welding and/or mechanical keying. This arrangement shall not permit any quick release dev
29、ice; the only method of loosening the clamp shall be by turning the screw in a counter-clockwise direction. 1.8 Finish Clamps shall be supplied in the “as machined” and lubricated condition. NOTEThe “lubricant” is the anti-seize compound applied during assembly. 1.9 Operation 1.9.1 The clamp shall e
30、xpand automatically when the tightening device is turned in a counter-clockwise direction. 1.9.2 For clamps of sizes larger than035, after expanding until the band is disconnected from the screw, it shall be possible to open the clamp to provide a gap equal to the largest diameter for which the clam
31、p is designed and so permit easy fitting or removal of the clamp by passing the clamp over the assembly. 1.9.3 The clamps shall be designed so that when tightened on the assembly they remain secure. NOTEIn some applications, locking wire may be specified. For details see Figure 2. 1.9.4 Clamps confo
32、rming to BSSP144 and BSSP146 are suitable for use over the temperature range65 C to+450 C. 1.9.5 Clamps conforming to BSSP145 and BSSP147 are suitable for use over the temperature range65 C to+300 C. 1.10 Marking and identification Clamps shall be clearly and indelibly marked with the following mini
33、mum information: 1) Manufacturers identification; 2) BritishStandard number (see Table 2). 3) Size of clamp, e.g.025.BSSP144-147:1971 BSI 02-2000 3 4) Clamps may be supplied to special order with the head drilled to take locking wire. These shall be identified by the letter “H”, e.g.BSSP146H025. Tab
34、le 2 Clamp identification 1.11 Information to be given in drawings for inspection purposes Certain features of the clamps are defined in Figure 2 by maximum envelope dimensions and in Section2 by functional test requirements. For inspection purposes however the Inspecting Authority 1)shall be provid
35、ed by the manufacturer with all the approved drawings 2) , with adequate dimensions and limits. No change shall be made to the approved drawings without the prior agreement of the Approving Authority, and the Inspecting Authority shall have the right to require a complete series of tests to be made
36、before accepting any clamp to the new drawings. 1.12 Information to be given in drawings and schedules, for call-up Clamps shall be identified on drawings and for ordering purposes by the BritishStandard number, code letter for head drilling, and the clamp size thus: 2 Inspection and testing 2.1 Gen
37、eral The clamps shall comply with the inspecting and testing requirements in this section. Tests shall be carried out to the satisfaction of the Inspecting Authority, at whose discretion any clamp may be required to be submitted to all or any of the subsequent tests. The manufacturer shall satisfy t
38、he Inspecting Authority that adequate control is maintained throughout manufacture to ensure compliance with the approved drawings. 2.2 Inspection of clamps Each clamp selected in accordance with2.3 shall be inspected for compliance with the approved drawings. BritishStandardnumber Type of clamp BSS
39、P144 BS SP145 BS SP146 BS SP147 Clamp with band with rolled or milled serrations (corrosion resisting steel) Clamp with band with rolled or milled serrations (nickel copper alloy) Clamp with band with pierced serrations (corrosion resisting steel) Clamp with band with pierced serrations (nickel copp
40、er alloy) 1) In the United Kingdom, the Inspecting Authority is the Aeronautical Quality Assurance Directorate (Ministry of Aviation Supply) for Military purposes, and the Air Registration Board for Civil purposes. 2) For clamps used on aircraft subject to British civil or military airworthiness req
41、uirements the drawings have to be approved by the Approving Authority, which is the Air Registration Board (through a design authority approved by the Board) or the Ministry of Aviation Supply, as appropriate.BSSP144-147:1971 4 BSI 02-2000 2.3 Samples for inspection and testing Before clamps are rel
42、eased by the manufacturers, the inspector shall take a random sample of the size specified in Table 3. A random sample is one for which every clamp in the batch has an equal chance of being taken. Clamps shall be taken at random from the sample and allocated to each test (see2.6 to2.11) in accordanc
43、e with the quantities specified in Table 3. Table 3 Sample requirements 2.4 Testing of samples 2.4.1 One series of tests in accordance with2.6 to2.11 shall be made on each batch of clamps subject to a maximum quantity of1000clamps in a batch and sampled in accordance with2.3. At the discretion of th
44、e Inspecting Authority the frequency of testing may be increased or decreased. 2.4.2 Unless otherwise, stated, a new clamp shall be used for each test; the number to be tested is indicated in Table 3. 2.4.3 All tests shall be carried out on clamps in the lubricated condition. 2.4.4 Where all the cla
45、mps in the sample satisfy the inspection and testing requirements the batch shall be deemed to comply with this standard. If, however, any manufacturing defects are found during inspection of the sample the remainder of the batch shall receive100% inspection. From the clamps that pass inspection a f
46、urther sample shall be taken for testing. If all the clamps in this second sample comply with the testing requirements the remainder of the batch shall be deemed to comply with this standard. Should any clamp from the first or second samples fail to comply with the testing requirements the batch rep
47、resented shall be deemed not to comply with this BritishStandard. 2.4.5 Clamps tested under this clause shall not be subsequently released, but shall be destroyed. 2.4.6 Clamps for type approval, to approve a new design or a new source of manufacture, shall be selected at random, from batches of cla
48、mps which have been manufactured by the methods and techniques to be used for subsequent quantity production. The Inspecting Authority will record the result of the type test by letter to the manufacturer. 2.4.7 Type approval and production tests for sizes larger than size125 shall be restricted to
49、those specified in2.6, and2.7. 2.5 Test apparatus 2.5.1 Details of the test apparatus to be used to ensure that clamps comply with the requirements of2.7, 2.8, 2.10, and2.11 is shown in Figure 4, Figure 5 and Figure 6. 2.5.2 Unless otherwise specified, the hose used in the tests shall be of the “ordinary” reinforced type suitable for aviation fuels and hot mineral oils (BS F67, Type3, or an agreed equivalent). 2.6 Tests on band material The strip for manufacture of the band shall withstand without cracking: 1) bending across the width of t
