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1、BRITISH STANDARD BS 3318:1978 ISO 5005:1977 Specification for Earth-moving machinery Method for locating the centre of gravity UDC 621.879:621.132:531.24 Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 29 06:10:12 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 3318:1978 This British Standard, hav
2、ing been prepared under the direction of the Road Engineering Standards Committee, was published under the authority of the Executive Board on 31 May 1978 BSI 12-1999 First published January 1961 First revision May 1978 The following BSI references relate to the work on this standard: Committee refe
3、rence RDB/21 Draft for comment 76/11809 DC ISBN 0 580 10235 1 Cooperating organizations The Road Engineering Standards Committee, under whose direction this British Standard was prepared, consists of representatives from the following Government departments and scientific and industrial organization
4、s: Asphalt and Coated Macadam Association Association of Consulting Engineers British Quarrying and Slag Federation British Tar Industry Association Cement and Concrete Association Concrete Society Limited Contractors Plant Association* County Surveyors Society Department of the Environment (PSA) De
5、partment of the Environment, Transport and Road Research Laboratory Department of Transport* Federation of Civil Engineering Contractors* Federation of Manufacturers of Construction Equipment and Cranes* Greater London Council Institute of Petroleum Institute of Quarrying Institution of Civil Engine
6、ers* Institution of Highway Engineers* Institution of Municipal Engineers* Institution of Structural Engineers Ministry of Defence* Refined Bitumen Association Ltd. Road Emulsion Association Ltd. Road Surface Dressing Association Sand and Gravel Association Limited Society of Chemical Industry Twist
7、 Drill and Reamer Association The organizations marked with an asterisk in the above list, together with the following, were directly represented on the committee entrusted with the preparation of this British Standard: Agricultural Engineers Association Associated Offices Technical Committee Depart
8、ment of Industry, Mechanical Engineering Health and Safety Executive National Coal Board Trades Union Congress Amendments issued since publication Amd. No.Date of issueComments Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 29 06:10:12 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 3318:1978 BSI
9、 12-1999i Contents Page Cooperating organizationsInside front cover National forewordii 0Introduction1 1Scope and field of application1 2Definitions1 3Preparation and loading of machine1 4Method of determination2 5Reference planes3 6Reporting of results3 Figure 1 Determination of the fore-and-aft co
10、-ordinate, 5 Figure 2 Determination of lateral co-ordinate in the horizontal plane, 6 Figure 3 Determination of vertical co-ordinate of the centre of gravity, 7 x y h Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 29 06:10:12 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 3318:1978 ii BSI 12-199
11、9 National foreword This British Standard is a revision of the 1961 version of BS 3318 and has been prepared under the direction of the Road Engineering Standards Committee. It is identical with ISO 5005 “Earth-moving machinery Method for locating the centre of gravity”. ISO 5005 was produced as a r
12、esult of international discussions in which the United Kingdom took an active part. This revision of BS 3318 differs from the 1961 version in that it applies specifically to earth-moving machinery and it now supersedes that edition. Terminology and conventions. The text of the International Standard
13、 has been approved as suitable for publication, without deviation, as a British Standard. 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
14、this standard, they should be interpreted as “British 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
15、from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 7 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 ins
16、ide front cover. Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 29 06:10:12 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 3318:1978 BSI 12-19991 0 Introduction Although there are many possible methods of determining the centre of gravity, the intent of this International Standard is to specify
17、one simple and practical method which requires the use of a weighbridge and crane. There is no single fixed position of the centre of gravity of a machine which has attachments or components that are movable. When such a machine is tilted, as it must be to find the vertical co-ordinates, flexible pa
18、rts deflect, fluids and loose parts move, and the position of the centre of gravity therefore changes. Again, particularly in the case of earth-moving machinery, the position of the centre of gravity will depend upon the nature and position of any attachments or ancillary equipment with which the it
19、em is fitted. It is therefore essential in all cases to state exactly the conditions of test. 1 Scope and field of application This International Standard specifies a method for determining the co-ordinates of the centre of gravity of earth-moving machinery such as tractors, loaders, dumpers and gra
20、ders in any condition of loading or position of attachments. 2 Definitions For the purpose of this International Standard the following definitions apply: 2.1 machine the machine or other object whose centre of gravity is to be determined 2.2 apparatus the equipment required to determine the centre
21、of gravity of a machine 2.3 attachment a piece of equipment which is available for mounting on the machine for a particular purpose (for example a bulldozer blade, winch or bucket) 2.4 “left-hand” and “right-hand” sides these terms apply when facing in the primary direction of travel 2.5 mass the ma
22、ss of the machine as submitted for test 3 Preparation and loading of machine The machine shall be clean and shall be tested in normal working conditions or in a specified condition agreed between the manufacturer and the testing authority. 3.1 Radiator, sump, hydraulic and other reservoirs, shall be
23、 filled to specified working levels; the fuel tank shall be full or empty or in a specified condition as agreed between the manufacturer and testing authority. 3.2 Tools, spare tyre, and loose accessories and equipment shall be complete as supplied and shall be in the normal stowage positions. 3.3 T
24、yre pressures shall be as specified in the manufacturers operating instructions or, if a range of pressures is allowed, at the highest pressure recommended. In the case of machines fitted with hydro-inflation tyres they shall be filled in accordance with the manufacturers operating instructions. 3.4
25、 The attachment shall be normally put in the operating position; for example: a) for crawler or wheeled tractors, with the dozer equipment lowered, tilt adjustment horizontal, to the lowest possible position just clear of the horizontal reference plane (see 5.3); b) for loaders with the bucket fully
26、 crowded back and the front linkage in such a position that the lower part of it or the bucket is just clear of the horizontal reference plane; Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 29 06:10:12 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 3318:1978 2 BSI 12-1999 c) for graders with th
27、e cutting edge of the blade horizontal and perpendicular to the horizontal axis of the machine and 20 cm above the horizontal reference plane. The front wheels shall be vertical. The centre of gravity may be determined in a similar manner with the attachment(s) in many different positions and the co
28、-ordinates for these different positions recorded as indicated in the report table at 6.4. 3.5 Articulated machines will normally be tested locked in a straight line, but the test may be required to be conducted with the joint set at the maximum or any intermediate angle. 3.6 When a scribing board i
29、s required it shall be at least 600 mm (24 in) high by 450 mm (18 in) wide, rigidly constructed, and attached to the machine in a suitable position with a smooth face vertical and parallel to the side or other appropriate plane (see clause 6). 4 Method of determination 4.1 Principle The suspension a
30、nd ground reaction method is used. This method involves measuring the ground reactions with the machine under test first level and second tilted in the fore-and-aft direction. The calculated horizontal distance of the centre of gravity from a ground contact point is measured in each case and vertica
31、ls drawn on a scribing board affixed to the machine. The intersection of the verticals (which in practice forms a small triangle) indicates the centre of gravity, the exact position being taken at the intersection of the medians. 4.2 Apparatus The following apparatus is suggested: 4.2.1 Weighbridge,
32、 calibrated, for example 20 kg (44 lb). 4.2.2 Crane 4.2.3 Decking 4.2.4 Knife edges (conveniently sized rolled steel angle). 4.2.5 Level conveniently combined in a field level. 4.2.6 Plumb rule conveniently combined in a field level. 4.2.7 Squares conveniently combined in a field level. 4.2.8 Scribi
33、ng board 4.2.9 Marking materials 4.2.10 Tape measure 4.3 Procedure The horizontal fore-and-aft co-ordinate, the lateral co-ordinate in the horizontal plane and the vertical co-ordinate of the centre of gravity shall be determined as stated in 4.3.1 to 4.3.3. 4.3.1 Horizontal fore-and-aft co-ordinate
34、, 4.3.1.1 TRACKED MACHINE (see Figure 1) Measure M, the mass of the whole machine, on the weigh-bridge. Measure r, the reaction under the knife edge due to its mass and part of the decking. Move the machine on to the decking part supported by the weighbridge and measure R + r. Measure P, the distanc
35、e between the knife edges. Calculate R by subtraction; then: Using this calculated value of , draw a perpendicular through the centre of gravity on the scribing board affixed to the machine. Then referto the appropriate reference plane in accordance with clause 5. 4.3.1.2 WHEELED MACHINES With wheel
36、ed machines it is not necessary to use decking or knife edges. With brakes off, measure axle loads and calculate , from the pitch of the axles. Then referto the appropriate reference plane in accordance with clause 5. x x R P M -= x x xx Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 29 06:10:1
37、2 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 3318:1978 BSI 12-19993 4.3.2 Lateral co-ordinate in the horizontal plane,(see Figure 2) Measure left-hand R1 and right-hand R2 wheels or track loadings. Calculate offset of centre of gravity using track gauge or wheel track as the moment arm. NOTEIt wi
38、ll usually be found that the right-hand and left-hand side loads do not total the mass of the machine exactly due to small differences in level between the weighbridge deck and the surround. Any error is minimized by equalizing the overlap of the side being weighed in both cases. It is preferable to
39、 use the total right-hand side and left-hand side wheel (track) loadings to determine the mass of the machine M. Then referto the appropriate reference plane in accordance with clause 5. 4.3.3 Vertical co-ordinate of the centre of gravity,(see Figure 3) 4.3.3.1 Suspend the machine under test from on
40、e end at an angle of 15 to 25 from the horizontal, the other end resting on the weighbridge. The maximum convenient angle should be employed. The method is applicable either to wheeled or tracked machines, the main difference being in establishing the exact location of the point of application of th
41、e ground reaction, i.e. the ground contact. In wheeled machines, which shall be unbraked, this is vertically below the axle. In tracked machines, it is necessary to manoeuvre until the contact-grousers are in line BB on either side or to make contact through a length of angle iron set on line BB. In
42、 all cases the suspension cable shall be vertical in both planes as tested by plumb rule. This is an essential condition to ensure that the ground reactions in the horizontal plane are zero. 4.3.3.2 Measure R, the reaction at the ground contact on the weighbridge. 4.3.3.3 Measure d, the horizontal d
43、istance from the ground contact to the line of suspension. 4.3.3.4 Calculate c, the horizontal distance from the centre of gravity to the line of suspension, from the formula 4.3.3.5 Draw the vertical through the centre of gravity on the scribing board fixed to the machine. Repeat with machine suspe
44、nded from the other end. The suspension angle need not be the same for both ends. The intersection of the verticals on the scribing board gives the position of the height of the centre of gravity. Refer this to the appropriate reference plane in accordance with clause 5. NOTEThe machine may be conve
45、niently run on the weighbridge, square, using chalked lines. This will assist in drawing the plan. If, with tracked machines, the grousers are not in line at B and B (see Figure 3) it is necessary to resort to trial and error by running the machine in varying circles till the required result is atta
46、ined at the last approach. 5 Reference planes The reference planes may conveniently be taken as follows: 5.1 Vertical 1: Through the driving sprocket axle if for a crawler tractor but through the front axle, or front idler centres, if a crawler or wheeled shovel as this is an important datum used in
47、 design. 5.2 Vertical 2: Through the major fore-and-aft axis of a machine, i.e. midway between the wheels or tracks. 5.3 Horizontal: Ground level. A hard contact shall be assumed, i.e. no grouser penetration in the case of a tracked machine. 6 Reporting of results 6.1 The report shall give the co-or
48、dinates of the centre of gravity: , horizontal fore-and-aft co-ordinate, being the distance from vertical 1; , lateral co-ordinate or displacement from the vertical 2; positive to the right, negative to the left; , vertical co-ordinate or height above the horizontal ground level. y y h c R d M - -=
49、h x y h Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 29 06:10:12 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 3318:1978 4 BSI 12-1999 6.2 The position of the centre of gravity shall be reported in millimetres to the nearest 10 mm from three reference planes. The reference planes, if other than those given in clause 5, shall be stated. 6.3 All details relevant to the position of the centre of gravity of the machine shall be reported (see clause 3). Details and positioning of attachment(s) and loading shall be stated. 6.4 A suggested