1、BRITISH STANDARD AEROSPACE SERIES CONFIRMED APRIL1998 BS SP 141:1970 Specification for Design and performance requirements for toggle type panel fasteners UDC629.7:621.828.2BSSP141:1970 This BritishStandard, having been approved by the Aerospace Industry Standards Committee, was published under the
2、authorityof the Executive Boardof the Institution on 31March1970 BSI02-2000 The following BSI reference relates to the work on this standard: Committee reference ACE/14 Draft for comment69/1719 ISBN 0 580 05867 0 Foreword This BritishStandard has been prepared at the request of the Society of Britis
3、h Aerospace Companies Limited. It specifies the requirements for design and performance of toggle type panel fasteners for aircraft. NOTEInformation concerning SI units is given in BS350, “Conversion factors and tables”, Part2, “Detailed conversion tables”, Supplement No.1, “Additional tables for SI
4、 conversions”, and PD5686, “The use of SI units”. This standard makes reference to the following BritishStandards: BS410, Test sieves. BS2011, Methods of environmental testing of electronic components and electronic equipment. Part2K. Salt mist. BSSP20, Panel type air filter elements for use with in
5、ternal combustion engines and compressors on aircraft. 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
6、 obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to7 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 cove
7、r. Amendments issued since publication Amd. No. Date CommentsBSSP141:1970 BSI 02-2000 i Contents Page Foreword Inside front cover 1 General 1 1.1 Scope 1 1.2 Definition 1 1.3 Materials 1 1.4 Protective treatment 1 2 Design requirements 1 2.1 General 1 2.2 Interchangeability 1 2.3 Operation 1 2.4 Flu
8、sh fitting 1 2.5 Capacity 1 2.6 Adjustment 2 2.7 Fitting tolerances 2 2.8 Shear type fasteners 2 3 Type tests 2 3.1 General 2 3.2 Tensile proof tests 2 3.3 Torsion proof tests 3 3.4 Tensile ultimate loads 3 3.5 Adjustment tests 3 3.6 Endurance test 3 3.7 Depth tolerance test 3 3.8 Malalignment test
9、3 3.9 Fluctuating load test 3 3.10 Operating test 4 3.11 Resistance to corrosion 4 3.12 Shear type fasteners 4 Appendix A Test schedule 6 Appendix B Dust and sand test 6 Figure 1 Measuring device for dust and sand tests 7 Table 1 Ultimate tensile loads 5 Table 2 Maximum operating loads 5 Table 3 Min
10、imum range of adjustment 5 Table 4 Ultimate shear loads 5 Table 5 Test schedule 6ii blankBSSP141:1970 BSI 02-2000 1 1 General 1.1 Scope This BritishStandard specifies the design and performance requirements for aircraft toggle type panel fasteners. 1.2 Definition For the purposes of this BritishStan
11、dard a toggle type panel fastener is a fastener which secures a panel or panels by the operation of a lever which moves a second lever over a dead centre to provide a geometric lock when in the closed position. 1.3 Materials All materials shall be to specifications agreed to by the Design Approving
12、Authority 1) . 1.4 Protective treatment Protective treatment shall meet the requirements of the Design Approving Authority (e.g.SBAC Publication RS.116). 2 Design requirements 2.1 General 2.1.1 Classification. For the purposes of this standard, toggle type panel fasteners shall be classified as Type
13、s A, B, C or D and “large” or “small” according to the performances specified in the relevant tables and qualified in accordance with3.1.1. 2.1.2 Installation. Fasteners shall be capable of being installed without the use of special tools. 2.1.3 Loose parts. The design shall be such that, after asse
14、mbly of a fastener in the position for which it is intended, there shall be no loose parts when the fastener is unlocked. 2.1.4 Resistance to foreign bodies. Fasteners shall be so designed that operation of their moving parts shall not be impeded by the presence of grit, or other foreign matter, inc
15、luding driven sand or snow. Fasteners shall at all times be capable of satisfactory operation without the application of a lubricant. 2.2 Interchangeability 2.2.1 Each fastener shall be directly interchangeable with any other fastener manufactured to the same specification or part number. 2.2.2 Wher
16、e fasteners are supplied in two or more portions, each portion shall be fully interchangeable with its counterpart from any other fastener of the same type. 2.3 Operation 2.3.1 Opening and closing, including locking, shall be possible with an arctic-gloved hand, and without the use of special tools.
17、 2.3.2 Each fastener shall be so designed that a positive lock restrains the operating lever from accidental operation, and from operation under all possible conditions of loading, including torsion. Where a large tab pressure area is provided on the lock, this shall be additionally restrained again
18、st movement due to negative air pressures. It shall not be possible to engage the lock, without the toggle mating members being properly engaged and closed. It must be immediately visually obvious that a fastener is in the unlocked condition. 2.3.3 Each type and size of fastener shall be operable ov
19、er a temperature range of from40 C to+70 C, and shall maintain efficient locking over a range of from75 C to+150 C, with the exception of Type D which shall maintain efficient locking up to+275 C. 2.4 Flush fitting When in the closed position, fasteners shall be flush with the outer surface of the p
20、anel. Gaps between the levers and the recess in the panel are to be kept to a minimum consistent with efficient operation. As far as is possible each fastener should be adaptable to a range of panel surface curvatures. 2.5 Capacity 2.5.1 Sizes. In general two sizes of fasteners, hereinafter classifi
21、ed as “large” size and “small” size, are required for Types A and B and these shall be capable of developing the ultimate loads specified in Table 1. 2.5.2 Operating loads. The mean force required to open or close a correctly aligned fastener, when applied at the outer end of the operating lever, an
22、d measured in increments of5 of arc, shall not exceed the amounts specified in Table 2, when loaded with15% of the relevant load given in Table 1. 1) In the United Kingdom the Design Approving Authority for fasteners is the Society of British Aerospace Companies Limited (SBAC)19, King Street, St. Ja
23、mess, London, S.W.1.BSSP141:1970 2 BSI 02-2000 2.6 Adjustment 2.6.1 Simple but adequate means shall be provided for the initial adjustment of tension, and for wear during the use of the fastener. Such adjustment shall be possible after installation, and shall not require other than the normal range
24、of hand tools. Means shall be provided whereby the setting can be locked at the correct adjustment, and a visible indication given that adjustment has not exceeded the safety limit. 2.6.2 The minimum range of adjustment shall be as specified in Table 3. 2.6.3 Adjustment should be infinitely variable
25、, but if made in definite steps, each step should be as small an increment as is possible. 2.7 Fitting tolerances 2.7.1 Malalignment. Fasteners shall operate efficiently when the two mating parts are displaced relative to each other, from the centre line of a fastener by a distance of not greater th
26、an1.5mm (large size) and0.75mm (small size). 2.7.2 Depth. Fasteners shall operate efficiently when the two mating parts are displaced relative to each other, in a direction normal to the panel surface, by a distance of not more than1.5mm (large size) and0.75mm (small size) for Type A fasteners and0.
27、75mm for Type B (large and small). 2.8 Shear type fasteners 2.8.1 General. In general, shear type fasteners shall conform to all of the preceding requirements with the exception of those in2.7.1 and2.7.2 which are inapplicable to fasteners of this type. 2.8.2 Fitting tolerances. The fitting toleranc
28、es will depend upon the design of the fastener and should be close enough to develop the required shear load without preventing freedom of operation. 2.8.3 Capacity. Each fastener shall be capable of developing an ultimate shear load, either in the plane of the panel or normal to it as specified in
29、Table 4. 3 Type tests 3.1 General 3.1.1 All samples shall undergo the appropriate tests detailed below, as scheduled in Appendix A to the satisfaction of the Inspecting Authority 2) . 3.1.2 Test reports countersigned by the Inspecting Authority witnessing the tests shall be forwarded together with t
30、he drawings to the Design Approving Authority. 3.1.3 The manufacturer shall disclose to the purchaser and Design Approving Authority any proposal to introduce constructions or processes differing from those used for the fasteners submitted to the type tests, and shall obtain the Design Approving Aut
31、horities written agreement before applying the change to production. 3.1.4 The tests specified in this standard are to be made on single fasteners, mounted on suitable rigs. In each case the number of fasteners to be tested, and the tests to which individual fasteners are to be subjected, shall be i
32、n accordance with Appendix A. 3.1.5 The provision of suitable test rigs and associated equipment is the responsibility of the fastener manufacturer, and shall be to the satisfaction of the Inspecting Authority. 3.1.6 Unless otherwise stated all tests shall be conducted at normal room temperature(15
33、C to20 C). 3.1.7 The sample fasteners shall be numbered as given in Appendix A for the purposes of recording and allocation of tests. 3.1.8 A fastener shall be deemed not to comply with this standard if it fails any relevant test, or when at the completion of the tests one or more of its components:
34、 1) exhibit undue wear or corrosion; 2) fracture or break; 3) have distorted or take up a permanent set,a) presenting the fastener from being locked or unlocked, orb) allowing the fastener to be unlocked with the application of75% or less of the absolute minimum torque; 4) show evidence of grain gro
35、wth. 3.2 Tensile proof tests 3.2.1 For the purpose of the tensile load tests, suitable test plates, in each of which are incorporated the fixed anchorage and lower socket, for the appropriate size and type of fastener shall be provided. The test plates shall have extensions for fitting in the testin
36、g machine. The test plates shall be sufficiently robust to withstand use during the ultimate load tests. 2) The Inspecting Authorities for fasteners in British civil or military aircraft are the Air Registration Board (through a Design Approving Authority approved by the Board) and the Ministry of T
37、echnology respectively.BSSP141:1970 BSI 02-2000 3 3.2.2 A direct steady load, equal to75% of the ultimate load specified in2.5.1, shall be applied in the appropriate direction for a period of5minutes. During and subsequent to that period, there shall be no visible sign of separation or distortion of
38、 any part of the test specimens, or of the bolts or rivets securing the specimens to the test appliance. Three samples of each size and type shall be tested in this manner. 3.3 Torsion proof tests Specimens shall be submitted to a torsion load equal to25% of the ultimate tensile load specified in2.5
39、.1. The torsion load shall be applied in both directions, slowly over a period of5cycles. No distortion of the test samples or of their mounting attachments shall be visible. 3.4 Tensile ultimate loads Continuing the test specified in3.2.2 one of the specimens shall be further tested under a direct
40、steady load, which shall be gradually increased until failure occurs. The failing load shall be not less than the minimum specified in2.5.1. In the event of doubt arising as a result of this test a further specimen shall be so tested. 3.5 Adjustment tests Efficiency of locking and of the adjustment
41、which governs the tension on the fastener is to be tested as specified in3.5.1 to3.5.3. 3.5.1 Types A, C and D fasteners. Each of three new samples shall be tested separately for adjustment. The fastener under test shall be adjusted until the load required to close the fastener is between44.5N and67
42、N (large size) or between26.5N and40N (small size). When the fastener adjustment is by finite steps the fastener shall be opened, the adjustment varied by one step, and the fastener again closed. The resulting operating load shall not exceed the values given in2.5.2. 3.5.2 Type B fasteners. Each of
43、three new samples shall be tested separately for adjustment. The fastener under test shall be adjusted so that the load required to close it is between22N and44.5N (large size) and between9N and18N (small size). When the fastener adjustment is by finite steps the fastener shall be opened, the adjust
44、ment varied by one step and again closed. The resulting operating load shall not exceed the values given in2.5.2. 3.5.3 Locking. Every possible attempt is to be made to engage the lock with the mating parts of the panels in various degrees of disengagement. It shall not be possible to close the lock
45、 except in the correct fully closed position of the panel. 3.6 Endurance test Three samples of each size and type are to be submitted to a locking/unlocking cycle test at15% of the relevant loads given in Table 1, performed at a rate not exceeding50cycles per minute, and shall withstand2000 complete
46、 cycles. Upon satisfactory conclusion of this test, one sample of each type shall be submitted to the torsion and ultimate tensile tests specified in3.3 and3.4, the requirements of which shall also be met. 3.7 Depth tolerance test One sample of each size and type shall be mounted in a suitable rig i
47、n which metal spacer strips of1.25mm or0.56mm (large and small size) are inserted to represent a corresponding difference between the planes of the panel surfaces. With the fasteners so arranged, no difficulty shall be experienced in locking or unlocking operations. The rig used for this test shall
48、be so devised, that it will also be suitable for the malalignment and repeat depth tolerance tests which follow. 3.8 Malalignment tests The same sample as used for the depth tolerance test, specified in3.7, shall be used for this test. The fastener shall be checked for operation with the panel membe
49、rs displaced relative to centre lines as detailed in2.7.1. Upon satisfactory completion of this test, and the displacement at each of the extremes of malalignment, the fastener shall be subjected to the depth test specified in3.7. 3.9 Fluctuating load test 3.9.1 Three samples of each size and type shall, in turn, be assembled in a suitable test rig, the fastener closing load adjusted to the appropriate value specified in3.5.1 and3.5.2 and the locking device rendered inoperative. The rig shall then be inverted so that the fastener opens vertically downwards, the
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