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 ordinary screw jack supports the weight by the thread self-locking function, and the framework is simple, however the transmission performance is usually low and the return stroke is sluggish. The thread of the self-propelled screw jack has no self-locking action and has a brake. When the brake is released, the weight could be quickly lowered alone and the return time can be shortened, but the framework of the jack is usually complicated. The screw jack can support heavy objects for a long period, and the utmost lifting capacity has reached 100 tons, which is widely used. After the horizontal screw is normally mounted on the lower part, the weight could be traversed at a little distance.

Principle of use:

The mechanical jack is one of the types of manual lifting tools. Its compact structure 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 drive the lifting sleeve so that the pounds rises or decline.


1. Before use, it’s important to check whether the jack is normal, whether the elements are flexible, increase lubricating oil, and properly estimate the fat of the heavy object. Make use of a jack of suitable tonnage and steer clear of overloading.

2. Adjust the technique of supporting the teeth on the rocker. Firstly, turn the rocker straight in the clockwise path by hand to make the lifting sleeve quickly ascend the very best weight.

3. Insert the handle in to the rocker hole, move the handle along, and the excess weight will rise. When the reddish colored warning line shows up on the lifting sleeve, the handle ought to be stopped instantly. If you need to lower the teeth in the opposite direction, the weight will start to fall.


1. Usually keep the top of 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 the lifting sleeve and the Conveyor Chain casing must be oiled anytime. Other essential oil filling holes ought to be lubricated regularly.

3. To be able to consider the protection used, avoid overloading, use illness, it is not appropriate to make use of multiple units to avoid danger.