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1、INTERNATIONAL STANDARD IS0 8720 First edition 1991-07-15 Passenger cars - Specifications for mechanical jacks Voitures particuli it shall then be possible to locate the jack correctly at each jacking point with a flat tyre to give the least favourable conditions, and to lift the vehicle off the grou
2、nd to give sufficient clearance between the ground and tyre-to fit the spare wheel, for all tyre sizes specified by the vehicle manufacturer. The spare wheel tyre shall be inflated to the maximum specified pressure. 5.2 Operational effort It shall be possible to perform the jacking operations descri
3、bed in 5.1 by applying a force that shall not exceed the following values: - 360 N for jacks operated by up and down lever action; - 120 N for all other types of jack operation. 5.3 Accidental operation At any point over its full travel while raising or lowering the vehicle, the jack mechanism shall
4、 not operate independently when the operating force is removed. 6 Stability 6.1 With the vehicle in the conditions specified in 5.1 and using the jack extended to its upper limit as specified in clause 7 at each jacking point in turn, a longitudinal static force of 250 N shall be applied in each dir
5、ection separately at a height of 44 cm above the road surface on the vehicle centreline. Furthermore a lateral static force of 250 N shall be applied in each direction separately to the middle of the wheels. The vehicle shall not come off the jack. -,-,- IS0 8720 : 1991 (El 6.2 With the vehicle load
6、ed as specified in 5.1 and parked on a surface having a gradient of (8 + 1) % and a camber of (5,5 I!C 0,5) % and with all other vehicle conditions as set by the manufacturer, the jacking procedure stipulated in 5.1 shall be carried out, first with the vehicle facing uphill and then facing downhill.
7、 The vehicle shall not come off the jack. 7 Durability NOTE - During this test the jack manufacturers instructions should be followed. With a new jack and handle, 24 jacking cycles evenly distributed around the jacking points shall be performed in accordance with the procedure -described in clause 5
8、. The upper limit of the jacking cycle is defined as the point at which there is 25 mm ground clearance with the largest fully inflated tyre/wheel combination or at which the jack is fully ex- tended, whichever occurs first. The lower limit is defined as the point at which the load is relieved from
9、the jack with the smallest deflated tyre/wheel combination. The 24 jacking cycles shall be carried out with a 5 min interval between two cycles. On completion of the test, the requirements of 5.2 shall con- tinue to be met and on visual inspection there shall be no undue wear or permanent deformation of either jack or handle. 2 -,-,- Is0 8720 : 1991 (E) UDC 829.113.012.732 Descriptors : road vehicles, private cars, screw jacks, specifications. Price based on 2 pages -,-,-
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