What is Screw Jack used for?

In our daily work, we often encounter situations where heavy objects need to be lifted. At this time, screw jacks are needed to help us complete the lifting operations of heavy objects. Screw jack refers to a lifting device that uses a rigid jacking piece as a working device to lift heavy objects within a small stroke of the top bracket claw. Screw jacks are used in a wide range of applications. Next, we will learn about their specific application scenarios.

What are screw jack application?

The screw jack has a large lifting capacity and is an ideal large-tonnage mechanical jack. It is widely used in building support, bridge construction, equipment handling and other occasions, bringing many conveniences to people's production and life. In terms of industry, it is also applicable to electric power, chemical industry, steel, bridge, machinery and other enterprises. Screw jacks can also be used for jacking up of equipment (heavy objects), disaster relief, power maintenance, static pile pressing, foundation settlement, ship building and other aspects. It is also suitable for fine-tuning operations, such as in small gaps and limited height space.

Working principle

The screw jack is one of the types of manual lifting tools. The screw jack can also be called a mechanical jack. Its structure is compact, and the swing of the rocker is used reasonably to make the pinion rotate. After a pair of bevel gears are combined, the screw is rotated to promote the lifting sleeve, whereby the weight is raised or lowered.

And its structure is very simple, the maximum lifting capacity can reach 100 tons. If the job is to use very bulky instruments or machinery, screw jacks are the most suitable weightlifting items.

How to use screw jack?

When using screw jacks, the following safety precautions should be observed:

1. The foundation of the screw jack. The foundation of the screw jack should be stable, solid and reliable. When setting the screw jack on the bottom surface, appropriate materials should be padded to expand the force bearing area.
2. Placement of the screw jack. When placing the screw jack on the soft ground, a wooden block should be placed under the jack to prevent it from tilting when it is free of force. When the weight rises, support skids should be placed under the weight at any time, but the hands should not stray into the danger zone.
3. During the placement of the jack, keep the action line of gravity center of the load consistent with the axis of the jack, and strictly prevent the danger of the jack being deflected or tilted due to the horizontal displacement of the jack's load during the lifting process. It is also necessary to prevent the jack from sliding in contact with the metal surface of the heavy object or the smooth surface of the concrete, and use hardwood blocks if necessary.
4. Lifting operation of the screw jack. The jacking height of the jack should not exceed the effective jacking distance. When lifting a large object (such as a girder), the two ends should be lifted and lowered separately, one end should be raised and lowered, and the other end must be padded, and stabilized. The jack is not allowed to be overloaded.
5. It is not advisable to start the jack in a hurry. It should rise rhythmically and at a uniform speed, and it should be slow when falling. When multiple jacks are used at the same time, they must be operated synchronously. After the operation of the screw jack, it is necessary to check carefully, check the oil pressure and hidden dangers, perform maintenance, and place it in an appropriate place.

Maintenance of screw jack

1. Always keep the surface of the machine body clean, regularly check whether the internal structure is intact, keep the pinion in the rocker flexible and reliable, and the lifting sleeve to move freely.
2. The friction surface between the lifting sleeve and the shell must be oiled at any time, and other oil holes should be lubricated regularly.
3. In order to consider the safety of use, avoid screw jack overloading, and it is not suitable to use multiple sets at the same time to avoid danger.
4. The liquid level of the oil tank should always be kept on the center line of the oil mark during work to prevent the oil grease pump from being sucked out. When refueling, use an oil filter to filter the impurities in the new oil. When used frequently, clean the oil filter every 2 months, clean the fuel tank every six months, and replace with new oil at the same time.
5. The normal working temperature of the jack oil pump is about 10-50°C. If the oil temperature is too high, take cooling measures or stop the pump. The oil temperature is too low, it is necessary to take warming measures or low-pressure operation to increase the oil temperature.
6. Before the motor starts, the reversing valve needs to be changed to the middle half position. Jog several times to prevent the high-pressure pump from being sucked out, and it can be used only after the air is removed.
7. The working pressure set by the pump at the factory shall not be increased arbitrarily.
8. When the high-pressure hose leaves the factory, it has passed a pressure test of 1.25 times the rated pressure. Due to the aging of the glue, users should pay attention to regular inspections when using them for a long time, once every six months. When checking and doing the pressure test, if leakage, protrusion or burst occurs, it must be replaced in time. When using, avoid discounts and sharp bends, and at the same time, do not get too close to the rubber hose to prevent blasting and hurting people.
9. The pump needs to be overhauled once a year. Clean all the parts with kerosene, pay attention to protect the various surfaces of the jack, and do not bump them arbitrarily. After assembly, each moving part should move flexibly without local jamming.