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 utilized as a jacking member. The ordinary screw jack supports the weight by the thread self-locking function, and the structure is simple, but the transmission effectiveness is certainly low and the return stroke is slow. The thread of the self-propelled screw jack has no self-locking action and is equipped with a brake. When the brake is normally released, the weight could be quickly lowered by itself and the return time can be shortened, but the structure of the jack can be complicated. The screw jack can support heavy items for a long time, and the maximum lifting capacity has Conveyor Chains reached 100 tons, which is widely used. Following the horizontal screw is mounted on the low part, the weight could be traversed at a small distance.
Principle of use:
The mechanical jack is among 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 pair of conical gears to operate a vehicle the screw to rotate and drive the lifting sleeve to ensure that the pounds rises or decline.
Instructions:
1. Before use, it is necessary to check whether the jack is regular, whether the components are flexible, add lubricating oil, and properly estimate the weight of the heavy object. Use a jack of appropriate tonnage and steer clear of overloading.
2. Adjust the technique 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 up and down, and the weight will rise. When the red warning line shows up on the lifting sleeve, the handle should be stopped immediately. If you want to lower the teeth in the contrary direction, the pounds will begin to fall.
Precautions:
1. Generally keep the surface of the machine clean, check the internal structure frequently, make the pinion in the rocker versatile and dependable, 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 should be lubricated regularly.
3. To be able to consider the safety used, avoid overloading, work with illness, it is 
not appropriate to use multiple units to avoid danger.