Internal structure of the screw jack

The screw jack, also referred to as the mechanical jack, is driven by a manpower through a screw pair, and a screw or nut sleeve is used as a jacking member. The ordinary screw jack supports the weight by the thread self-locking function, and the framework is simple, but the transmission performance can be low and the come back stroke is slow. The thread of the self-propelled screw jack does not have any self-locking action and is equipped with a brake. When the brake is usually released, the weight could be quickly lowered by itself and the return time can be shortened, but the structure of the jack is normally complicated. The screw jack can support heavy items for a long time, and the utmost lifting capacity has already reached 100 tons, which is widely used. Following the horizontal screw is usually mounted on the low part, the weight can be traversed at a small distance.

Principle of use:

The mechanical jack is one of the types of manual lifting tools. Its compact framework makes reasonable use of the rocking of the rocker to rotate the pinion. It is operated by a set of conical gears to drive the screw to rotate and press the lifting sleeve to ensure that the pounds rises or decline.


1. Before use, it’s important to check whether the jack is China Air Compressor normal, whether the parts are flexible, put lubricating oil, and properly estimate the excess weight of the large object. Use a jack of suitable tonnage and prevent overloading.

2. Adjust the technique of supporting one’s teeth on the rocker. Firstly, turn the rocker straight in the clockwise direction by hand to make the lifting sleeve quickly ascend the top weight.

3. Insert the handle into the rocker hole, move the handle up and down, and the weight will rise. When the red warning line shows up on the lifting sleeve, the handle should be stopped instantly. If you need to lower the teeth in the opposite direction, the excess weight will begin to fall.


1. Usually keep the top of machine clean, examine the internal structure regularly, make the pinion in the rocker flexible and dependable, and lift the lifting sleeve freely.

2. The friction surface between the lifting sleeve and the casing must be oiled anytime. Other oil filling holes should be lubricated regularly.

3. In order to consider the basic safety in use, avoid overloading, use illness, it is not appropriate to use multiple units to avoid danger.