The screw jack, also known 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 normal screw jack supports the weight by the thread self-locking function, and the framework is simple, but the transmission effectiveness is certainly low and the come back stroke is gradual. The thread of the self-propelled screw jack has no self-locking action and is equipped with a brake. When the brake can be released, the weight could be quickly lowered alone and the return time can be shortened, but the framework of the jack is certainly complicated. The screw jack can support heavy objects for a long period, and the utmost lifting capacity has reached 100 tons, which is trusted. After the horizontal screw is Speed Gearbox definitely mounted on the lower 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 structure makes reasonable usage of the rocking of the rocker to rotate the pinion. It is operated by a pair of conical gears to operate a vehicle the screw to rotate and drive the lifting sleeve so that the weight rises or decline.
Instructions:
1. Before use, it’s important to check whether the jack is regular, whether the elements are flexible, put lubricating oil, and correctly estimate the pounds of the heavy object. Use a jack of suitable tonnage and steer clear of overloading.
2. Adjust the method of supporting the teeth on the rocker. Firstly, turn the rocker directly in the clockwise path 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 weight will rise. When the reddish warning line shows up on the lifting sleeve, the handle should be stopped immediately. If you need to lower one’s teeth in the contrary direction, the fat will begin to fall.
Precautions:
1. Generally keep the top of machine clean, verify the internal structure regularly, make the pinion in the rocker flexible and reliable, and lift the lifting sleeve openly.
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. In order to consider the protection used, avoid overloading, work with illness, it is not appropriate to use multiple units in order to avoid danger.