BS 3318-1978 Specification for earth-moving machinery - method for locating the centre of gravity《土方机械规范 重心定位方法》.pdf

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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 621.879:621.132:531.24BS3318:1978 This British Standard, having been prepared under the directionof the Road EngineeringStandards Committee, was published underthe autho

2、rity of the Executive Board on 31May1978 BSI 12-1999 First published January1961 First revision May1978 The following BSI references relate to the work on this standard: Committee reference RDB/21 Draft for comment 76/11809 DC ISBN 0 580 10235 1 Cooperating organizations The Road Engineering Standar

3、ds Committee, under whose direction this British Standard was prepared, consists of representatives from the following Government departments and scientific and industrial organizations: Asphalt and Coated Macadam Association Association of Consulting Engineers British Quarrying and Slag Federation

4、British Tar Industry Association Cement and Concrete Association Concrete Society Limited Contractors Plant Association* County Surveyors Society Department of the Environment (PSA) Department of the Environment, Transport and Road Research Laboratory Department of Transport* Federation of Civil Eng

5、ineering Contractors* Federation of Manufacturers of Construction Equipment and Cranes* Greater London Council Institute of Petroleum Institute of Quarrying Institution of Civil Engineers* Institution of Highway Engineers* Institution of Municipal Engineers* Institution of Structural Engineers Minis

6、try of Defence* Refined Bitumen Association Ltd. Road Emulsion Association Ltd. Road Surface Dressing Association Sand and Gravel Association Limited Society of Chemical Industry Twist Drill and Reamer Association The organizations marked with an asterisk in the above list, together with the followi

7、ng, were directly represented on the committee entrusted with the preparation of this British Standard: Agricultural Engineers Association Associated Offices Technical Committee Department of Industry, Mechanical Engineering Health and Safety Executive National Coal Board Trades Union Congress Amend

8、ments issued since publication Amd. No. Date of issue CommentsBS3318:1978 BSI 12-1999 i Contents Page Cooperating organizations Inside front cover National foreword ii 0 Introduction 1 1 Scope and field of application 1 2 Definitions 1 3 Preparation and loading of machine 1 4 Method of determination

9、 2 5 Reference planes 3 6 Reporting of results 3 Figure 1 Determination of the fore-and-aft co-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 hBS3318:1978 ii BSI 12-1999 National fore

10、word This British Standard is a revision of the1961version of BS3318and has been prepared under the direction of the Road Engineering Standards Committee. It is identical with ISO5005 “Earth-moving machinery Method for locating the centre of gravity”. ISO5005 was produced as a result of internationa

11、l discussions in which the United Kingdom took an active part. This revision of BS3318differs from the1961version in that it applies specifically to earth-moving machinery and it now supersedes that edition. Terminology and conventions. The text of the International Standard has been approved as sui

12、table 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 this standard, they shoul

13、d 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 from legal obligations. S

14、ummary of pages This document comprises a front cover, an inside front cover, pagesiandii, pages1to7 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.BS3318:1978 BSI

15、 12-1999 1 0 Introduction Although there are many possible methods of determining the centre of gravity, the intent of this International Standard is to specify one simple and practical method which requires the use of a weighbridge and crane. There is no single fixed position of the centre of gravi

16、ty 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 parts deflect, fluids and loose parts move, and the position of the centre of gravity therefore changes. Again, particularly in the case of e

17、arth-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 item is fitted. It is therefore essential in all cases to state exactly the conditions of test. 1 Scope and field of application This Interna

18、tional Standard specifies a method for determining the co-ordinates of the centre of gravity of earth-moving machinery such as tractors, loaders, dumpers and graders in any condition of loading or position of attachments. 2 Definitions For the purpose of this International Standard the following def

19、initions 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 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 ex

20、ample 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 mass of the machine as submitted for test 3 Preparation and loading of machine The machine shall be clean and shall be tested in normal worki

21、ng conditions or in a specified condition agreed between the manufacturer and the testing authority. 3.1 Radiator, sump, hydraulic and other reservoirs, shall be filled to specified working levels; the fuel tank shall be full or empty or in a specified condition as agreed between the manufacturer an

22、d 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 Tyre pressures shall be as specified in the manufacturers operating instructions or, if a range of pressures is allowed, at the highest pres

23、sure recommended. In the case of machines fitted with hydro-inflation tyres they shall be filled in accordance with the manufacturers operating instructions. 3.4 The attachment shall be normally put in the operating position; for example: a) for crawler or wheeled tractors, with the dozer equipment

24、lowered, tilt adjustment horizontal, to the lowest possible position just clear of the horizontal reference plane (see5.3); b) for loaders with the bucket fully 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 pla

25、ne;BS3318:1978 2 BSI 12-1999 c) for graders with the cutting edge of the blade horizontal and perpendicular to the horizontal axis of the machine and20cm above the horizontal reference plane. The front wheels shall be vertical. The centre of gravity may be determined in a similar manner with the att

26、achment(s) in many different positions and the co-ordinates for these different positions recorded as indicated in the report table at6.4. 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

27、 intermediate angle. 3.6 When a scribing board is required it shall be at least 600mm (24in) high by450mm (18in) 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 (seeclause6). 4 Method of det

28、ermination 4.1 Principle The suspension and 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 p

29、oint is measured in each case and verticals 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 a

30、pparatus is suggested: 4.2.1 Weighbridge, calibrated, for example 20kg (44lb). 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

31、combined in a field level. 4.2.8 Scribing 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 in4.3.1 to4.3.3. 4.3.

32、1 Horizontal fore-and-aft co-ordinate, 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

33、measure R + r. Measure P, the distance 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 clause5.

34、 4.3.1.2 WHEELED MACHINES With wheeled 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 clause5. x x R P M - = x x x xBS3318:1978 BSI 12-1999 3

35、4.3.2 Lateral co-ordinate in the horizontal plane,(see Figure 2) Measure left-hand R 1and right-hand R 2wheels or track loadings. Calculate offset of centre of gravity using track gauge or wheel track as the moment arm. NOTEIt will usually be found that the right-hand and left-hand side loads do not

36、 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 use the total right-hand side and left-hand side wheel (track) loading

37、s to determine the mass of the machine M. Then referto the appropriate reference plane in accordance with clause5. 4.3.3 Vertical co-ordinate of the centre of gravity, (see Figure 3) 4.3.3.1 Suspend the machine under test from one end at an angle of15 to25 from the horizontal, the other end resting

38、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 the ground reaction, i.e. the ground contact. In wheeled machines, which sh

39、all 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 all cases the suspension cable shall be vertical in both planes as teste

40、d 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 distance from the ground contact to the line of suspension. 4.3.3.4 Calcul

41、ate 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 suspended from the other end. The suspension angle need not be the same for bo

42、th 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 clause5. NOTEThe machine may be conveniently run on the weighbridge, square, using chalked lines. This will ass

43、ist in drawing the plan. If, with tracked machines, the grousers are not in line at B and B (seeFigure 3) it is necessary to resort to trial and error by running the machine in varying circles till the required result is attained at the last approach. 5 Reference planes The reference planes may conv

44、eniently 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 design. 5.2 Vertical 2: Through the major fore-and-aft axis of a machine,

45、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-ordinates of the centre of gravity: , horizontal fore-and-aft co-ordinate, be

46、ing the distance from vertical1; , lateral co-ordinate or displacement from the vertical2; 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 - = h x y hBS3318:1978 4 BSI 12-1999 6.2 The position of the centre of gravity sha

47、ll be reported in millimetres to the nearest10mm from three reference planes. The reference planes, if other than those given in clause5, shall be stated. 6.3 All details relevant to the position of the centre of gravity of the machine shall be reported (seeclause3). Details and positioning of attac

48、hment(s) and loading shall be stated. 6.4 A suggested form of report is shown below. Machine mass M Unladen Laden . . . . . . . . . . . kg (lb) . . . . . . . . . . . kg (lb) Left-hand side Right-hand side Total Co-ordinates of centre of gravity, mm Position of attachment(s) x y h x y hBS3318:1978 BS

49、I 12-1999 5 Figure 1 Determination of the fore-and-aft co-ordinate, xBS3318:1978 6 BSI 12-1999 Figure 2 Determination of lateral co-ordinate in the horizontal plane, yBS3318:1978 BSI 12-1999 7 Figure 3 Determination of vertical co-ordinate of the centre of gravity, hBS 3318:1978 ISO 5005:1977 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing BritishStandards. It presents the UK view on standards in Europe and at the international level. I