BS-6268-1982 ISO-6544-1981.pdf

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 measurements UDC 621.542:621.883:531.781 Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 05:52:23 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6268:1982 This British Standard, having been prepared under the direction of the Mechanical Engineering Standards Committee, was published under the authority of the Board of BSI and comes into effect on 30 July 1982 © BSI 09-1999 The following BSI references relate to the 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 marked 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 CommitteeDepartment of Trade (Marine Division) Association of Consulting EngineersDepartment of Transport Association of Hydraulic EquipmentElectricity Supply Industry in England and ManufacturersWales* Association of Mining, Electrical andEnergy Industries Council* Mechanical EngineersEngineering Equipment Users Association British Compressed Air Society*Federation of Manufacturers of Construction British Constructional Steelwork AssociationEquipment and Cranes British Electrical and Allied ManufacturersHealth and Safety Executive* Association (BEAMA)*Institution of Gas Engineers* British Gas Corporation*Institution of Mechanical Engineers* British Gear Manufacturers AssociationInstitution of Plant Engineers British Internal Combustion EngineInstitution of Production Engineers Manufacturers AssociationLloyds Register of Shipping British Pump Manufacturers AssociationLondon Transport Executive British Steel Corporation Machine Tool Industry Research Association British Steel IndustryMinistry of Defence* British Valve Manufacturers Association Ltd.National Coal Board* Chartered Institution of Building ServicesOil Companies Materials Association Crown Agents for Oversea Governments andProcess Plant Association AdministrationsSociety of Motor Manufacturers and Traders Department of Industry (MechanicalLimited 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 AssociationInstitution of Mining Engineers Imperial College of Science and TechnologySouth Wales Institute of Engineers Institute of Marine EngineersCoopted member Institution of Mining and Metallurgy Amendments issued since publication Amd. No.Date of issueComments Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 05:52:23 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6268:1982 © BSI 09-1999i Contents Page Cooperating organizationsInside front cover National forewordii 0Introduction1 1Scope and field of application1 2References1 3Definitions and symbols1 4Methods for measurement of reaction torque3 Figure 1 Torque-time curve5 Figure 2 High and low torque rate joints6 Table 1 Symbols and units2 Table 2 Subscripts3 Publications referred toInside back cover Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 05:52:23 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6268:1982 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 ISO 6544:1981 “Hand-held pneumatic assembly tools for installing threaded fasteners Reaction torque and torque impulse measurements” prepared by Technical Committee 118, Compressors, pneumatic tools and pneumatic machines, and published by the International Organization for Standardization (ISO). Terminology and conventions. The text of the International 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” appear, 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 ISO 2787, ISO 5393 and ISO 5941, 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 application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Cross-references International Standard Corresponding British Standard ISO 31BS 5775 Specification for quantities, units and symbols (Identical) ISO 1000:1981BS 5555:1981 Specification for SI units and recommendations for the use of their multiples and of certain other units (Identical) ISO 3534:1977BS 5532:1978 Statistics Vocabulary and symbols (Identical) Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 8, 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 amendment table on the inside front cover. Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 05:52:23 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6268:1982 © BSI 09-19991 0 Introduction This International Standard covers the test method for measurement of reaction torque 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 accordance 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 test joints with standardized torque rates that are in accordance with those specified in the performance test of ISO 5393. 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 installing 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 assembly 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, 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 Definitions1) 3.1.1 installed torque the 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 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 impulse correspond to measurements made at an effective inlet pressure of 6,3 bar 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 than 6,3 bar, the test pressure must be specified each time a torque is cited. Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 05:52:23 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6268:1982 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 tu and a high time limit td corresponding to the threshold torque level on the torque time curve (see Figure 1) 3.1.5 reaction torque impulse (IM) the torque impulse over the reaction time span of the tightening cycle defined by 3.1.6 reaction force impulse (IF) applicable to angle wrenches, pistol grip wrenches and other wrenches when the force in the handle 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 of 6,3 bar2). 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 of 6,3 bar 3.2 Symbols 3.2.1 Symbols and units are chosen according to ISO 31 and ISO 1000 when applicable. 3.2.2 The symbols and units used in this International Standard are given in Table 1. 3.2.3 The subscripts used in this International Standard are given in Table 2. Table 1 Symbols and units 2) 1 bar = 100 kPa SymbolQuantityUnit MAInstallation torqueN·m MRReaction torqueN·m FRReaction forceN tReaction times bEffective 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 RMReference torque rate for the low torque rate test jointN·m/rev RLActual torque rate for the low torque rate test jointN·m/rev ILTorque impulse measured on joint with torque rate RLN·m·s IMReaction torque impulseN·m·s MTThreshold torqueN·m IFReaction force impulseN·s Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 05:52:23 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6268:1982 © BSI 09-19993 Table 2 Subscripts 4 Methods for measurement of reaction torque 4.1 General rules for tests 4.1.1 All measurements carried out 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 observations 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 mechanism. 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 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 characteristics 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 writing 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 when the tool is rigidly mounted. No dynamic effects are present in this case and the following relations are valid: MR = MA FR = 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. SubscriptDesignation uLow time limit for impulse measurements dHigh time limit for impulse measurements MTorque AInstallation RReaction aMomentarily applied rMomentary reaction FForce HHigh torque rate joint LLow torque rate joint TThreshold MA b - - Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 05:52:23 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6268:1982 4 © BSI 09-1999 4.2.2 Low torque rate 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 MR = MA FR = These relationships are valid regardless of 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 Mr = Ma, and in this case The reaction torque impulse is recorded by means of a torque-time integrator. Alternatively the torque is plotted as a function of time for evaluation of the torque impulse from the torque-time curve shown in Figure 1. Time limits tu and td are 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 reaction 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 joint should be performed on a joint with the torque rate corresponding to an angular displacement of 360° as the torque is increased from 50 % to 100 % o