Jacks are divided into mechanical jacks and hydraulic jacks, their principles are different. In principle, the most basic principle on which hydraulic transmission is based is Pascal’s law. In this way, in a balanced system, the pressure applied to the smaller piston is relatively small, while the pressure applied to the larger piston is relatively large, so that the liquid can be kept still. Therefore, through the transfer of liquid, different pressures at different ends can be obtained, and the purpose of a transformation can be achieved. The hydraulic jack commonly used by people uses this principle to achieve force transmission. The screw jack is used to reciprocate the handle, and the pawl pulls the ratchet gap back and forth. The small bevel gear drives the large bevel gear to rotate the weight lifting screw, so that the lifting sleeve can be raised or lowered to achieve the function of lifting tension. The hydraulic jack is simple.
(1) Screw jack: Its advantage is that it is safe and reliable. The disadvantages are slow speed, low efficiency, small lifting weight, lifting weight is generally 5 ~ 50t, minimum height is 250 ~ 700mm, and lifting height is 130 ~ 400m
Attention to use:
① Before use, check the screw and nut for cracks or wear.
② When using, the bottom must be cushioned with sleepers or wooden boards to prevent it from sliding, and the base cushion must be leveled.
Positive, so as not to subject the screw to additional bending load, at the same time, it is not allowed to use it at overload, and the jacking height is not allowed to exceed the specified value.
③ Transmission parts should be lubricated frequently
(2) Hydraulic jack: It has the advantages of large load, stable rise, safety and reliability, labor saving and simple operation. The lifting weight is generally 3 ~ 320t, the minimum height is 200 ~ 450mm, and the lifting height is 130 ~ 200mm.
① Before use, check whether the lifting piston and other parts are flexible and the oil circuit is smooth.
② When using, the bottom should be placed on a strong and solid foundation, with iron plates and sleepers underneath and wooden boards on the top to prevent heavy objects from sliding.
③ When the crane stops working midway, lock it tightly.
④ The lifting height of the large piston is not allowed to exceed the specified value, and the length of the handle is not allowed to be arbitrarily, so as not to overload the jack.