1、BRITISH STANDARD BS 7262:1990 Specification for Automatic safe load indicators UDC 621.873.1/.2/.3:621.317.782:621.039.587:629.1.018:614.8BS7262:1990 This British Standard, having been prepared under the directionof the Mechanical Handling Standards Policy Committee, was published underthe authority
2、 of the BoardofBSI and comes into effect on 28February 1990 BSI 07-1999 The following BSI references relate to the work on this standard: Committee reference MHE/3 Draft for comment 88/72855 DC ISBN 0 580 18145 6 Committees responsible for this British Standard The preparation of this British Standa
3、rd was entrusted by the Mechanical Handling Standards Policy Committee (MHE/-) to Technical Committee MHE/3, upon which the following bodies were represented: Associated British Ports Associated Offices Technical Committee Association of Consulting Engineers British Ports Federation and the National
4、 Association of Ports Employers British Railways Board British Steel Corporation Construction Plant-Hire Association Department of the Environment (Building Research Establishment) Department of Trade and Industry (Mechanical Engineering and Manufacturing Technology Division) Electricity Supply Indu
5、stry in England and Wales Engineering Equipment and Materials Users Association Federation of Civil Engineering Contractors Federation of Manufacturers of Construction Equipment and Cranes Federation of Wire Rope Manufacturers of Great Britain Health and Safety Executive Independent Engineering Insu
6、rers Committee Institute of Materials Management Institution of Mechanical Engineers Institution of Plant Engineers Institution of Production Engineers Institution of Structural Engineers Lloyds Register of Shipping Welding Institute Coopted member Amendments issued since publication Amd. No. Date o
7、f issue CommentsBS7262:1990 BSI 07-1999 i Contents Page Committees responsible Inside front cover Foreword ii 1 Scope 1 2 Definitions 1 3 General 1 4 Mechanical 8 5 Electrical 8 6 ASLIs using programmable electronic systems 10 7 Type testing 10 8 Protection and painting 17 9 Marking of equipment 17
8、10 Instruction manual 17 Appendix A British Standards for material and equipment suitable for use in the manufacture of automatic safe load indicators 18 Appendix B Legislation related to cranes 19 Figure 1 Interpolated duties 4 Figure 2 Stepped duties 5 Figure 3 Graph of safe working load against r
9、adius 6 Figure 4 Block diagram showing the position of the interference pulse generator for the test specified in 7.2.6.4 15 Table 1 Form of warnings 3 Table 2 Indications required for ASLIs for different types of cranes 7 Table 3 Summary of tests 11 Table 4 Test sequence 12 Table 5 Common and diffe
10、rential mode transient overvoltage tests for mains supplied ASLI 13 Table 6 Common and differential mode transient overvoltage tests for generator supplied ASLI 14 Table 7 Common and differential mode transient overvoltage tests for vehicle supplied ASLI 14 Table 8 Data cable interference test 14 Pu
11、blications referred to Inside back coverBS7262:1990 ii BSI 07-1999 Foreword This British Standard was prepared under the direction of the Mechanical Handling Standards Policy Committee. Automatic safe load indicators have been used with cranes for many years. Before this standard was introduced, the
12、 design, manufacture and type testing of these devices was largely influenced by the need, in certain circumstances, to use an automatic safe load indicator of a type approved by the Health and Safety Executive. This standard was developed from a specification produced by the Health and Safety Execu
13、tive to define the essential requirements required for approval. This British Standard replaces the Health and Safety Executives specification with regard to all aspects of approval under Health and Safety Legislation. It is important to ensure that close cooperation exists between manufacturers and
14、 purchasers in order that automatic safe load indicators are correctly specified, installed and operated. This British Standard has been written on the basis that the automatic safe load indicator manufacturer is responsible for the specification, installation and type testing of the automatic safe
15、load indicator in conjunction with the crane on which it is to be used. 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 im
16、munity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages1 to 20, 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 t
17、he amendment table on the inside front cover.BS7262:1990 BSI 07-1999 1 1 Scope This British Standard specifies constructional and testing requirements for automatic safe load indicators for cranes. It is common practice to fit devices associated with an automatic safe load indicator which prevent ce
18、rtain motions of the crane after the point has been reached where the overload warning is given; these additional motion limiting features are not covered by this British Standard. Appendix A lists British Standards for material and equipment suitable for use in the manufacture of automatic safe loa
19、d indicators. Appendix B details legislation relating to cranes. NOTEThe titles of the publications referred to in this standard are listed on the inside back cover. 2 Definitions For the purposes of this British Standard the following definitions apply. 2.1 safe load indicator a device which when f
20、itted to a crane gives, within certain specified tolerance limits (see 3.8.2 and3.8.3), a warning of the approach to the safe working load of the crane, and a further warning when the safe working load has been exceeded NOTE 1In addition, a safe load indicator may have to supply certain defined info
21、rmation (see 3.8.5) associated with the safe use of the crane. NOTE 2Rated capacity indicator is an equivalent term. 2.2 automatic safe load indicator (ASLI) a safe load indicator which requires no manual resetting or adjustment, from the application of a load to the crane until the release of that
22、load 2.3 configuration the combination of structural members, counterweights, hook block reeving and other items which when assembled according to the crane manufacturers instructions permit the crane to lift a range of safe working loads 2.4 fail to a safe condition a condition in which a fault cau
23、ses an overload warning or some equally obvious indication to be given by the ASLI 2.5 radius for slewing cranes, the horizontal distance between the point at which the axis of rotation meets the ground and the vertical centre line through the hook. For non-slewing cranes, the horizontal distance be
24、tween the front axle or other forward support and the vertical centre line through the crane hook 2.6 safe working load (SWL) the maximum load that can be lifted by the crane under certain specified conditions NOTE 1The safe working loads for a particular crane and, when appropriate, corresponding o
25、perating radii or jib angle are given in the current certificate of test for that crane. NOTE 2Rated capacity is an equivalent term. 2.7 actual load the mass of all loads and of all lifting attachments suspended from the hook or fixed lifting appliance. For mobile cranes the mass of the hook block,
26、if fitted, is also included in the actual load NOTESeealso ISO4306-1 ADD2. 2.8 watchdog a hardware timer which monitors the duration of internal hardware functions, and/or application program functions, and/or system software functions, and which will fail to a safe condition if not periodically res
27、et at a predetermined interval 2.9 continuous warning a warning that is given visually by either a flashing or uninterrupted light or audibly by either a pulsing or uninterrupted sound and persists throughout the time that the condition being indicated exists 2.10 protective circuit the circuit whic
28、h includes connections to the conductive mass of the crane which might in turn be connected to earth mass 3 General 3.1 Construction All parts of the automatic safe load indicator necessary for its operation shall comply with this standard for all configurations of the type of crane to which it is t
29、o be fitted. For a particular crane, the ASLI shall comply with this standard for all safe working loads indicated on the SWL charts of that crane. NOTE 1The safe working loads given on the SWL chart for a crane should be consistent with those given on the test certificate.BS7262:1990 2 BSI 07-1999
30、An automatic safe load indicator shall operate automatically to the extent that from the application of a load to the release of that load, using any motion or combination of motions permitted by the crane manufacturer, no manual resetting or adjustment of the safe load indicator is required. The lo
31、cation/design of the configuration selecting device shall prevent alteration of the configuration during the lifting cycle while remaining readily accessible between lifting operations. NOTE 2The design should minimize the risk of accidental or inaccurate changing of any manual setting device. For e
32、xample, toggle switches, which can be easily knocked to change the setting, are unsuitable and a switch having a number of possible settings exceeding the number of crane configurations by ten would be unsatisfactory. NOTE 3The equipment should be sufficiently robust in its construction and/or prote
33、cted to prevent damage from shock, vibration and the general rigours of crane duties including erection, rope changing, use and dismantling or maintenance including arc welding on the crane. NOTE 4Special consideration should be given to the material strength of any part of the construction that is
34、likely to be exposed to accidental damage. The ASLI shall function such that at intermediate radii, between those shown on the SWL chart for the crane, it follows an interpolation of a smooth curve graph of the plots of the safe working loads and the radii given on the SWL chart. For telescopic jib
35、cranes capable of operating at intermediate jib lengths, between those shown on the crane SWL chart, the ASLI shall follow the duties determined for the crane by the crane designer. Where the duties are of interpolated form the ASLI shall function as illustrated by the three dimensional graph shown
36、in Figure 1. Where the duties are of stepped form the ASLI shall function as illustrated by the three dimensional graph shown inFigure 2. 3.2 Environmental operating conditions The correct operation (see 3.8) of the ASLI shall not be affected by the mechanical shocks and vibration transmitted by the
37、 crane structure during transportation and operation. The ASLI shall be designed to operate in ambient temperatures between 20 C and +60 C. It shall be designed, constructed and installed so that when tested in accordance with7.2.4 to 7.2.10, the ASLI meets the relevant acceptance criteria in accord
38、ance withTable 3. The ASLI shall be protected against rain, water spray, frost, snow, dirt, dust, condensation or other adverse conditions. The degree of protection shall be in accordance with 5.7. NOTE 1Steps should be taken to dissipate any heat which may be generated within an enclosure that coul
39、d possibly affect the correct operation of the ASLI. NOTE 2Guidance on the degree of protection to be adopted for explosive atmospheres is given in BS5345-1. NOTE 3The automatic safe load indicator should be protected against corrosion (see clause 8). NOTE 4The construction and installation of the a
40、utomatic safe load indicator should give adequate protection from all the effects of lightning so far as is reasonably practicable. 3.3 Overload testing of crane The design of the ASLI shall permit overload testing of the crane without any disconnection or adjustment. 3.4 Provision for routine inspe
41、ction and verification The ASLI shall be designed so that it can be verified other than by applying loads to the crane (see 3.9 and 6.4). NOTEThe need for routine inspection and testing should be taken into account at the design stage. When testing the ASLI without the application of loads it may be
42、 practicable for limit switches to be operated manually without the need for additional facilities. However specific provision may need to be made for checking other devices such as those incorporating electrical resistances. 3.5 Security All adjusters affecting the performance of the ASLI shall be
43、located within enclosures or at a position giving the same level of security. 3.6 Special provision for the rigging of mobile cranes The ASLI design shall allow for rigging operations on mobile cranes by either of the following: a) the installation of a rigging switch, which, when activated, causes
44、the audible overload warning provided for persons in the vicinity of the crane to be cancelled, but which allows the remaining audible overload warning provided for the driver to remain in full operation at all times; NOTE 1The rigging switch should be arranged such that it cannot be left inadverten
45、tly activated when rigging operations are completed and the crane is restored to normal duties. NOTE 2It is important to emphasize that this facility should only be provided to avoid the disturbance otherwise caused during long rigging operations. b) the indicator giving all the appropriate warnings
46、 whenever a load is applied to the crane when it is in the rigging position. 3.7 Control positions and markings All visual warning devices, information displays, switches and controls shall have clear markings on or adjacent to them, with symbols or words in English to indicate their function and mo
47、de of operation (see ISO 7000). NOTEDue consideration should be given to good ergonomic practices both in the operation of controls and in the presentation of warnings and information.BS7262:1990 BSI 07-1999 3 3.8 Warnings and indications 3.8.1 General. The ASLI shall give warnings and indications i
48、n accordance with 3.8.2 to 3.8.4 for all permitted motions of the crane that induce an overload and for all configurations shown on the certificate of test and thorough examination of the crane to which it is fitted. NOTEAll graduations and markings on analogue instruments should be clearly visible
49、from the crane operating position and should enable all the positions and loads given on the certificate of test and thorough examination of the crane to be clearly distinguished within the specified accuracy. All pointers and similar devices should provide a fast response to changing conditions and be suitably damped to prevent excessive oscillation or overrun. 3.8.2 Warning of approach to SWL. The ASLI shall give a clear and continuous warning of approach to SWL. The warning shall commence at not less than90 % of the SWL and at not more than 97.5 %
