Jack itself is a common tool, which is used to repair the slewing bearing, ring gear and other parts of the excavator, or to repair the whole chassis. In order to stably support the upper structure of hundreds of tons of excavator, wooden stacks were often used in the past, and the use process was complicated. Now, professional jack is very important. Usually, the special jack has 3-4 groups of hydraulic props, each group includes 1-2 hydraulic cylinders, and the lifting capacity is up to 1300T. In order to lift smoothly and avoid the damage of slewing pivot and other slewing parts, the hydraulic prop must be synchronized. In the structure, there are two ways of direct support and beam support. The direct support is relatively simple and economical. The beam supporting structure is more complex, but the compatibility and flexibility are better, and the stability is better, which can resist the wind or other possible safety risks. Either way, there is a problem of support point. For the direct support mode, the support point at the rear end is very easy, but the front end often needs to be connected to the boom cylinder support of the excavator or the boom support of the wire rope excavator with an auxiliary bracket, which means that the boom cylinder or boom needs to be removed. If the front support point is convenient and the chassis does not need to be moved, it is unnecessary to remove the boom cylinder or boom. Although the beam support method also needs to use auxiliary support, due to different forces, it is usually not necessary to dismantle the oil cylinder or boom. In addition, for the jack, the locking device is also essential to avoid safety hazards.
