1、BRITISH STANDARD BS 6268:1982 ISO 6544:1981 Method of measurement for Reaction torque and torque impulse from hand-held pneumatic assembly tools for installing threaded fasteners ISO title: Hand-held pneumatic assembly tools for installing threaded fasteners Reaction torque and torque impulse measur
2、ements UDC 621.542:621.883:531.781BS6268:1982 This British Standard, having been prepared under the directionof the Mechanical Engineering Standards Committee, was published underthe authority of the BoardofBSI and comes into effect on 30July1982 BSI 09-1999 The following BSI references relate to th
3、e work on this standard: Committee reference MEE/39 Draft for comment 80/78597 DC ISBN 0 580 12838 5 Cooperating organizations The Mechanical Engineering Standards Committee, under whose direction this British Standard was prepared, consists of representatives from the following: The organizations m
4、arked with an asterisk in the above list, together with the following, were directly represented on the Technical Committee entrusted with the preparation of this British Standard: Associated Offices Technical Committee Department of Trade (Marine Division) Association of Consulting Engineers Depart
5、ment of Transport Association of Hydraulic Equipment Electricity Supply Industry in England and Manufacturers Wales* Association of Mining, Electrical and Energy Industries Council* Mechanical Engineers Engineering Equipment Users Association British Compressed Air Society* Federation of Manufacture
6、rs of Construction British Constructional Steelwork Association Equipment and Cranes British Electrical and Allied Manufacturers Health and Safety Executive* Association (BEAMA)* Institution of Gas Engineers* British Gas Corporation* Institution of Mechanical Engineers* British Gear Manufacturers As
7、sociation Institution of Plant Engineers British Internal Combustion Engine Institution of Production Engineers Manufacturers Association Lloyds Register of Shipping British Pump Manufacturers Association London Transport Executive British Steel Corporation Machine Tool Industry Research Association
8、 British Steel Industry Ministry of Defence* British Valve Manufacturers Association Ltd. National Coal Board* Chartered Institution of Building Services Oil Companies Materials Association Crown Agents for Oversea Governments and Process Plant Association Administrations Society of Motor Manufactur
9、ers and Traders Department of Industry (Mechanical Limited Engineering) Telecommunication Engineering and Department of Industry (National Engineering Manufacturing Association (TEMA) Laboratory)* Water-tube Boilermakers Association Department of the Environment (PSA) Construction Plant-hire Associa
10、tion Institution of Mining Engineers Imperial College of Science and Technology South Wales Institute of Engineers Institute of Marine Engineers Coopted member Institution of Mining and Metallurgy Amendments issued since publication Amd. No. Date of issue CommentsBS6268:1982 BSI 09-1999 i Contents P
11、age Cooperating organizations Inside front cover National foreword ii 0 Introduction 1 1 Scope and field of application 1 2 References 1 3 Definitions and symbols 1 4 Methods for measurement of reaction torque 3 Figure 1 Torque-time curve 5 Figure 2 High and low torque rate joints 6 Table 1 Symbols
12、and units 2 Table 2 Subscripts 3 Publications referred to Inside back coverBS6268:1982 ii BSI 09-1999 National foreword This British Standard, which has been prepared under the direction of the Mechanical Engineering Standards Committee, is identical with ISO6544:1981 “Hand-held pneumatic assembly t
13、ools for installing threaded fasteners Reaction torque and torque impulse measurements” prepared by Technical Committee118, Compressors, pneumatic tools and pneumatic machines, and published by the International Organization for Standardization (ISO). Terminology and conventions. The text of the Int
14、ernational Standard has been approved as suitable for publication as a British Standard without deviation. Some terminology and certain conventions are not identical with those used in British Standards; attention is especially drawn to the following. Wherever the words “International Standard” appe
15、ar, referring to this standard, they should be read as “British Standard”. The comma has been used throughout as a decimal marker. In British Standards it is current practice to use a full point on the baseline as the decimal marker. The Technical Committee has reviewed the provisions of ISO2787, IS
16、O5393 and ISO5941, to which reference is made in the text, and has decided that they are acceptable for use in conjunction with this standard. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct appli
17、cation. Compliance with a British Standard does not of itself confer immunity from legal obligations. Cross-references International Standard Corresponding British Standard ISO 31 BS 5775 Specification for quantities, units and symbols (Identical) ISO 1000:1981 BS 5555:1981 Specification for SI unit
18、s and recommendations for the use of their multiples and of certain other units (Identical) ISO 3534:1977 BS 5532:1978 Statistics Vocabulary and symbols (Identical) Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages1 to 8, an inside back cover and a
19、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.BS6268:1982 BSI 09-1999 1 0 Introduction This International Standard covers the test method for measurement of reaction to
20、rque and torque impulse from hand-held pneumatic assembly tools for installing threaded fasteners and specifies how such measurements should be evaluated. Such methods are important for the following purposes a) enabling manufacturers to measure reaction torque impulse from assembly tools in accorda
21、nce with a standardized method and to offer their products under correlated technical specifications; b) giving users standardized technical information on reaction torque and torque impulse from pneumatic tools for threaded fasteners. The values of reaction torque and torque impulse are measured on
22、 test joints with standardized torque rates that are in accordance with those specified in the performance test of ISO5393. 1 Scope and field of application This International Standard specifies a test method for evaluation of reaction torque and torque impulse from hand-held pneumatic tools for ins
23、talling threaded fasteners and gives instructions on how measured data should be evaluated and presented. This International Standard is directly applicable to assembly torque control tools. In the case of stall type tools, only the reaction torque can be measured. Impacting, pulsing or ratcheting a
24、ssembly tools are not covered. 2 References ISO 31, Quantities, units and symbols. ISO 1000, SI units and recommendations for the use of their multiples and of certain other units. ISO 2787, Rotary and percussive pneumatic tools Acceptance tests. ISO 3534, Statistics Vocabulary and symbols. ISO 5393
25、, Rotary pneumatic assembly tools for threaded fasteners Performance test. ISO 5941, Compressors, pneumatic tools and machines Preferred pressures. 3 Definitions and symbols The following definitions and symbols are specific to this International Standard. 3.1 Definitions 1) 3.1.1 installed torque t
26、he peak torque transmitted to the joint when installing a threaded fastener by use of a hand-held pneumatic assembly tool 3.1.2 reaction torque the peak torque transmitted to the operator when installing a threaded fastener by use of a hand-held pneumatic assembly tool 3.1.3 reaction force the peak
27、force transmitted to the operator when installing a threaded fastener by use of a hand-held pneumatic assembly tool 1) Where reference is made to this International Standard, it is to be understood that indicated values of reaction torque, reaction force, reaction torque impulse and reaction force i
28、mpulse correspond to measurements made at an effective inlet pressure of6,3bar and the tool adjusted in such a way that the test torque level equals the rated torque of the tool. If for any reason the test pressure is other than6,3 bar, the test pressure must be specified each time a torque is cited
29、.BS6268:1982 2 BSI 09-1999 3.1.4 reaction time duration of reaction torque exceeding threshold torque values specified in this International Standard during a tightening cycle. The reaction time is the time span between a low time limit t uand a high time limit t dcorresponding to the threshold torq
30、ue level on the torque time curve (seeFigure 1) 3.1.5 reaction torque impulse (I M ) the torque impulse over the reaction time span of the tightening cycle defined by 3.1.6 reaction force impulse (I F ) applicable to angle wrenches, pistol grip wrenches and other wrenches when the force in the handl
31、e is of primary interest 3.1.7 test torque level the mean torque measured at actual test conditions, when the tool is tested on the low torque rate joint 3.1.8 rated torque the specific term used for mean torque when measured on the low torque rate joint at an effective test pressure of6,3 bar 2) .
32、For torque control tools, the rated torque value is determined with the highest setting of the torque control means in accordance with the manufacturers recommendation and an effective test pressure of6,3 bar 3.2 Symbols 3.2.1 Symbols and units are chosen according to ISO31 and ISO1000 when applicab
33、le. 3.2.2 The symbols and units used in this International Standard are given inTable 1. 3.2.3 The subscripts used in this International Standard are given inTable 2. Table 1 Symbols and units 2) 1 bar = 100 kPa Symbol Quantity Unit M A Installation torque Nm M R Reaction torque Nm F R Reaction forc
34、e N t Reaction time s b Effective length of tool (length of lever arm of an applicable type wrench measured from the centre of the grip handle to the spindle centre) m R M Reference torque rate for the low torque rate test joint Nm/rev R L Actual torque rate for the low torque rate test joint Nm/rev
35、 I L Torque impulse measured on joint with torque rate R L Nms I M Reaction torque impulse Nms M T Threshold torque Nm I F Reaction force impulse NsBS6268:1982 BSI 09-1999 3 Table 2 Subscripts 4 Methods for measurement of reaction torque 4.1 General rules for tests 4.1.1 All measurements carried out
36、 in compliance with this International Standard shall be performed by competent persons and with accurate instrumentation, which is calibrated against existing standard methods. 4.1.2 Air supply and lubrication consistent with the manufacturers specification shall be provided. 4.2 General observatio
37、ns 4.2.1 High torque rate joints On high torque rate joints, the tightening process is of extremely short duration. Torque is applied to the fastener for a very short period of time, which is determined by the time required to reach the present torque level and the delay time of the torque release m
38、echanism. It has been demonstrated that the relationship between installed torque and the reaction torque and reaction force is influenced by the mass inertia of the tool, the size of the operator and the way the tool is held by the operator. The reaction torque can be both higher and lower than the
39、 installed torque. Likewise the reaction force can be both higher and lower than the installed torque divided by the effective length of the tool. Various attempts of measuring reaction force and reaction torque on high torque rate joints in a test rig that simulates standard operator characteristic
40、s have not been encouraging. It is considered to be beyond the scope of this International Standard to determine such Standard operator conditions that would yield results which are in complete correspondence with the actual stress experienced by human operators. Nor are there, at the time of writin
41、g this International Standard, any known devices for measuring torque and force that can be used between the tool and the operator. As a consequence it must be realized that for high torque rate joints, accurate values of reaction torque and reaction force can only be obtained in the special case wh
42、en the tool is rigidly mounted. No dynamic effects are present in this case and the following relations are valid: M R= M A F R= These relations are also approximately true when the operator holds the tool in such a way that the direction of the reaction force coincides with his straight arm. Subscr
43、ipt Designation u Low time limit for impulse measurements d High time limit for impulse measurements M Torque A Installation R Reaction a Momentarily applied r Momentary reaction F Force H High torque rate joint L Low torque rate joint T Threshold M A b -BS6268:1982 4 BSI 09-1999 4.2.2 Low torque ra
44、te joints On low torque rate joints, the dynamic effects are negligible and consequently the reaction torque is equal to the installed torque and the reaction force is equal to the installed torque divided by the effective length of the tool M R= M A F R= These relationships are valid regardless of
45、how the tool is held or mounted. 4.3 Torque and torque impulse measurements 4.3.1 The reaction torque impulse is defined by But for a rigidly mounted tool M r= M a , and in this case The reaction torque impulse is recorded by means of a torque-time integrator. Alternatively the torque is plotted as
46、a function of time for evaluation of the torque impulse from the torque-time curve shown inFigure 1. Time limits t uand t dare triggered by a threshold torque setting on the torque-time integrator or the torque amplifier. 4.3.2 The reaction force impulse is defined by but , for a rigid mount. The re
47、action force impulse can consequently be calculated from the reaction torque impulse. 4.3.3 When the reaction torque impulse is measured on a low torque rate joint the result is a function of the torque rate of the joint. Ideally the measurement of reaction torque impulse on the low torque rate join
48、t should be performed on a joint with the torque rate corresponding to an angular displacement of360 as the torque is increased from50% to100% of the test torque level. The corresponding torque rate is denoted R M . (See Figure 1) M A b - F r M a b - = I F I M b - =BS6268:1982 BSI 09-1999 5 For prac
49、tical reasons it is acceptable to measure reaction torque impulse on a low torque rate joint with a lower torque rate than R M . The actual torque rate of the low torque rate joint is denoted R L . The corresponding measured value of the reaction torque impulse is denoted I L . The reaction torque impulse corresponding to torque rate R Mcan then be calculated from 4.3.4 The assembly tool shall be rigidly mounted in the test stand. 4.3.5 The assembly tool shall be tested on both a high and a low tor
