1、BRITISH STANDARD BS 7705:1993 ISO 11169: 1993 Specification for Brake systems for special wheeled forestry machines UDC 630:631.37-592:620.1BS7705:1993 This British Standard, having been prepared under the directionof the Agricultural Machinery and Implements Standards Policy Committee, waspublished
2、 under the authorityof the Standards Boardand comes into effect on 15October1993 BSI 12-1999 The following BSI references relate to the work on this standard: Committee reference AGE/29 Draft for comment 91/79517 DC ISBN 0 580 22338 8 Committees responsible for this British Standard The preparation
3、of this British Standard was entrusted by the Agricultural Machinery and Implements Standards Policy Committee (AGE/-) to Technical Committee AGE/29, upon which the following bodies were represented: Agricultural Engineers Association Arboricultural Association British Agricultural and Garden Machin
4、ery Association Consumers Association Department of Trade and Industry Forestry Commission Health and Safety Executive Hire Association Europe National Farmers Union Coopted members Amendments issued since publication Amd. No. Date CommentsBS7705:1993 BSI 12-1999 i Contents Page Committees responsib
5、le Inside front cover National foreword ii 1 Scope 1 2 Definitions 1 3 Instrument accuracy 2 4 General requirements 2 5 Test conditions 3 6 Performance tests 3 7 Test report 5 Annex A (informative) Bibliography 6 Table 1 Instrument accuracy levels 2 Table 2 Maximum test force levels for braking syst
6、em controls 3 Table 3 Results 5BS7705:1993 ii BSI 12-1999 National foreword This British Standard BS7705has been prepared under the direction of the Agricultural Machinery and Implements Standards Policy Committee. It is identical with ISO11169Machinery for forestry wheeled special machines Vocabula
7、ry, performance test methods and criteria for brake systems published by the International Standards Organization (ISO). 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 wit
8、h a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 6 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated.
9、This will be indicated in the amendment table on the inside front cover.BS7705:1993 BSI 12-1999 1 1 Scope This International Standard lays down the vocabulary and specifies performance test methods and criteria to enable uniform assessment of the service, secondary and parking brake systems of wheel
10、ed specially designed forestry machines. This International Standard applies to self-propelled, rubber-tyred special forestry machines defined in ISO68141 as skidders, forwarders and the various feller-buncher combination machines. 2 Definitions For the purposes of this International Standard, the f
11、ollowing definitions apply. 2.1 brake systems All the components which combine together to stop and/or hold the machine. Such systems include the control(s), means of power transmission, the brake(s) and all parts connecting the brake to the wheel and tyre. 2.1.1 service brake system primary system
12、used for stopping and holding the machine 2.1.2 secondary brake system system used for stopping the machine in the event of any single failure in the service brake system 2.1.3 parking brake system system used to hold a stopped machine in a stationary position 2.1.4 brake system components (See 2.1.
13、4.1, 2.1.4.2, 2.1.4.3 and 2.1.4.4.) 2.1.4.1 control(s) component(s) directly activated by the operator to cause a force to be transmitted to the brake(s) 2.1.4.2 brake actuation system all of the components between the control(s) and the brake(s) which connect them functionally 2.1.4.3 brake(s) comp
14、onents which directly apply a force to oppose movement of the machine. Brakes may, for example, be of friction, electrical or fluid types 2.1.4.4 retarder energy-absorption device normally used to control machine speed while descending gradients 2.2 common component component that performs a functio
15、n in two or more brake systems 2.3 machine mass mass of the machine which includes the heaviest combination of manufacturer-approved equipment (i.e. winch, dozer, felling head, grapple, etc.) and components (i.e. cab, protective structures, etc.), an operator of75kg and full fuel, lubricating, hydra
16、ulic and cooling systems the mass of forwarders includes the manufacturers rated payload 2.4 stopping distance, s distance travelled by the machine from the point on the test course at which the machine brake control is initially actuated to the point where the machine comes to a complete halt 2.5 m
17、ean deceleration, a average rate of change of the velocity of the machine from the instant the brake control is initially actuated until the machine comes to a complete halt the mean deceleration, a, in metres per second squared, may be determined from the equation: where 2.6 burnish procedure to co
18、ndition the frictional surfaces of the machine brake(s) 2.7 brake reservoir pressure pressure in the air or hydraulic reservoir(s), if so equipped, to assist the application of force to the brakes v is the velocity of the machine immediately prior to the brake control being activated, in metres per
19、second; s is the stopping distance, in metres. a v 2 2s - =BS7705:1993 2 BSI 12-1999 2.8 brake system pressure gas or hydraulic pressure available at the brake mechanism 2.9 test course surface upon which the test is carried out 2.10 cold brakes brakes in one of the following conditions: a) the brak
20、es have not been actuated in the previous1h, except in accordance with 5.9; b) the brakes have been cooled to100 C or less when measured on the brake disc or the outside of the brake drum; c) in the case of totally enclosed brakes, including oil-immersed brakes, the temperature measured on the outsi
21、de of the housing is below50 C, or within the manufacturers specification. 3 Instrument accuracy The instruments used to carry out the required measurements shall be accurate to the levels given in Table 1. Table 1 Instrument accuracy levels 4 General requirements The requirements for brake systems
22、in 4.1 to 4.6 apply to all machines indicated in clause 1. 4.1 Required brake systems All machines shall be equipped with a) a service brake system; b) a secondary brake system; c) a parking brake system. No brake system shall be connected to the wheel and tyre through a disconnect such as a clutch
23、or shiftable gear-box. 4.2 Common components Brake systems may use common components; however in the event of a failure of any single component other than a tyre, the brake systems shall be capable of bringing the machine to a halt in accordance with performance requirements specified for the second
24、ary brake system in 6.6.3.4. 4.3 Service brake system 4.3.1 All machines shall meet the service brake performance requirements of 6.5 and 6.6. 4.3.2 The temperature of brake components exposed to debris shall not exceed120 C over ambient when measured within1min after completing the stopping test de
25、scribed in 6.6. The point of measurement shall be the outer surface of the drum or the periphery of the disc. 4.3.3 If other systems are provided with power from the service brake system, any failure in these systems shall be considered as a failure in the service brake system. 4.4 Secondary brake s
26、ystem All machines shall meet the secondary brake performance requirements of 6.6. The secondary brake system shall be actuated by a manual control, in addition, automatic application is permitted if a warning device is actuated prior to the automatic application. 4.5 Parking brake system 4.5.1 All
27、machines shall meet the parking brake performance requirements of 6.5. 4.5.2 All machines shall be equipped with a parking brake system capable of being applied by a person seated in the drivers seat. 4.5.3 While applied, the parking brake system shall maintain, parking performance in compliance wit
28、h6.5, despite any contraction of the brake parts, exhaustion of the source of energy, or leakage of any kind. 4.5.4 The parking brake system may use common components which also form part of other brake systems provided that the requirements given in6.5 are met. 4.6 Warning device 4.6.1 The service
29、brake system using stored energy as its primary application force shall be equipped with a warning device which actuates before system energy drops below either50% of the manufacturers specified maximum operating energy level or the level required to meet the secondary brake performance requirements
30、, whichever is higher. Parameter being measured and related unit Instrument accuracy % Brake system pressure (kPa) 3 Machine speed (km/h) 3 Machine mass (kg) 2,5 Stopping distance (m) 1 Brake control actuating force (N) 3 Slope (%) 1BS7705:1993 BSI 12-1999 3 This warning device shall be readily visi
31、ble and/or audible to the operator, and provide a continuous warning. Gauges shall not be acceptable to meet these requirements. 4.6.2 Any friction-type parking brake system not automatically disengaged by engagement of the transmission, or which does not automatically disengage the transmission whe
32、n applied, shall be equipped with a warning device which is activated when the engine is running, the transmission is engaged, and the parking brake is engaged. This warning device shall provide continuous warning to the operator. Gauges shall not be acceptable to meet these requirements. 5 Test con
33、ditions 5.1 Precautions specified by the manufacturer shall be taken while carrying out performance tests. 5.2 The test course shall consist of a hard, dry surface with a well-compacted base. Ground moisture may be present to the extent that it does not adversely affect the braking test. The test co
34、urse shall not have a gradient of more than3% at right angles to the direction of travel. Gradient in the travel direction shall be as specified for the test being carried out. The approach to the test course shall be of sufficient length, smoothness and uniformity of gradient to ensure the required
35、 machine speed is reached before the brakes are applied. 5.3 The machine mass shall be as defined in 2.3 and shall not exceed the axle distribution specified by the manufacturer. The manufacturers rated payload shall be included for forwarders only, up to the maximum machine gross mass and the axle
36、loads approved by the manufacturer. 5.4 All parameters relating to brake systems, i.e. tyre size and pressure, brake adjustment, warning device actuation point, etc., shall be within the machine manufacturers specifications. All the brake system pressures shall be within the machine manufacturers sp
37、ecification range. No manual adjustment shall be made to the brake system during any single performance test. 5.5 When the machine transmission provides a selection of gear ratios, the stopping tests shall be carried out with the transmission in a gear suitable for the test speed specified. The powe
38、r train may be disengaged prior to completing the stop. 5.6 Retarders shall not be used in these tests unless the retarder is simultaneously actuated by the applicable brake system control. 5.7 Blades, grapples and other equipment shall be carried in the transport position recommended by the manufac
39、turer. 5.8 Burnishing or conditioning of brakes before testing is permissible. The burnishing procedure shall be indicated in the operators and/or maintenance manual for the machine and shall be verified by consulting the machine manufacturer. 5.9 Immediately prior to a test, the machine shall be op
40、erated until the machine fluids, i.e. engine and transmission oils, are at normal operating temperature. 5.10 Machine speed shall be measured immediately prior to the brake control being applied. 5.11 As a minimum requirement, all data required for the completion of the test report in clause 7 shall
41、 be recorded and reported. 6 Performance tests 6.1 Brake system control 6.1.1 Control forces needed to meet the required braking performance for the systems defined in 2.1 shall not exceed the levels given in Table 2. Table 2 Maximum test force levels for braking system controls 6.1.2 All brake syst
42、em controls shall be capable of being applied by someone sitting in the operators seat. The secondary and parking brake system(s) control(s) shall be arranged so that they cannot be released from the operators seat once they have been applied unless they can be reapplied immediately from the operato
43、rs seat. 6.2 Service brake system recovery capacity (stored energy system) The engine speed control (throttle) shall be set to obtain maximum engine rotational speed (r/min) or frequency (min 1 ). The service brake system shall be capable of delivering at least70% of the pressure measured during the
44、 first brake application after the service brake has been fully applied20times at the rate of six applications per minute. Type of control Maximum test force to be applied N Finger grasp 20 Hand grasp upwards 400 fore/aft 300 sideways 300 Foot pedal (foot control) 600 Foot pedal (ankle control) 350B
45、S7705:1993 4 BSI 12-1999 Calculate the percentage of the service brake system stored energy residual pressure, $p, after the brake application test, from the following equation: where 6.3 Secondary brake system capacity (stored energy system) If the stored energy reservoir(s) of the service brake sy
46、stem are used to apply the secondary brake system, then, with the energy source disconnected and the machine stationary, the capacity of the service brake system reservoir(s) shall be such that energy remaining in the reservoir(s) after five full service brake applications shall not be less than tha
47、t required to meet the secondary stopping requirements specified in 6.6.3.4. 6.4 Warning device for stored energy system The service brake system energy shall be reduced by any suitable means. The warning device (see 4.6.1) shall be activated before the system energy drops below either50% of the max
48、imum stored energy level specified by the manufacturer or the stored energy level required to meet the secondary stopping requirement specified in6.6.3.4, whichever level is higher. The warning device shall be activated before a secondary brake system is automatically applied. 6.5 Holding performanc
49、e 6.5.1 The service brake system shall have a capability equivalent to holding the machine stationary, in both forward and reverse directions, on a40% gradient with the machine mass specified in5.3. 6.5.2 The parking brake shall have a capability equivalent to holding the machine stationary, in both forward and reverse directions, under the conditions specified in 6.5.1. 6.5.3 If the machine slides or if it is otherwise impractical to test on a40% gradient, use the surface specified in 5.2 with not more than1% gradient in
