The screw jack, also called 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 normal screw jack supports the excess weight by the thread self-locking function, and the framework is simple, however the transmission performance is normally low and the return stroke is sluggish. The thread of the self-propelled screw jack does not have any self-locking action and has a brake. When the brake is normally released, the weight can be quickly lowered by itself and the return period can be shortened, however the structure of the jack can be 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. After the horizontal screw is definitely mounted on the low part, the weight can be traversed at a small distance.

Principle of use:

The mechanical jack is among the types of manual lifting tools. Its compact structure makes reasonable use of the rocking of the rocker to rotate the pinion. It really is operated by a pair of conical gears to drive the screw to rotate and drive the lifting sleeve to ensure that the excess weight rises or decline.


1. Before use, it’s important to check if the jack is regular, whether the components are flexible, increase lubricating oil, and properly estimate the excess weight of the large object. Make use of a jack of appropriate tonnage and prevent overloading.

2. Adjust the method of supporting the teeth on the rocker. First of all, turn the rocker straight in the clockwise direction by hand to help make the lifting sleeve quickly ascend the top weight.

3. Insert the handle in to the rocker hole, move the handle along, and the pounds will rise. When the reddish Conveyor Chains colored warning line appears on the lifting sleeve, the handle should be stopped instantly. If you want to lower the teeth in the contrary direction, the fat will start to fall.


1. Always keep the surface of the machine clean, examine the internal structure frequently, make the pinion in the rocker versatile and reliable, and lift the lifting sleeve freely.

2. The friction surface between your lifting sleeve and the housing must be oiled anytime. Other oil filling holes ought to be lubricated regularly.

3. To be able to consider the security in use, avoid overloading, work with illness, it isn’t appropriate to make use of multiple units in order to avoid danger.