Pneumohydraulic Jacks: Rolling Jacks For 20 Tons And Other Varieties, Principle Of Operation, Device Of Cargo Bottle Jacks

2024 Author: Beatrice Philips | [email protected]. Last modified: 2024-01-09 13:15

Any car must have a jack. No one is immune from an unpleasant situation on the road, such as the need to replace a wheel. For this, this tool is used.

Device and principle of operation

Consider several types of jacks, from complex to simple.

A pneumohydraulic jack is a device for lifting large loads (from 20 to 50 tons) to a certain height. Consists of the following parts:

• a body made of high-strength metal;
• rod - a retractable piston, which directly affects the efficiency of using the device;
• liquids and oils.

The device has two levers of action - mechanical and hydraulic.

For the operation of the pneumohydraulic jack, a special hydraulic oil of specific viscosity and density is used. With daily use of the jack, the oil is changed once a month, with rare use - once or twice a month, and if it is practically not used, the oil must be changed once a year.

Principle of operation: a force is applied by means of a mechanical lever to the piston of a small cylinder . The process takes place according to the law of hydrostatics. The pressure applied to the free surface of the liquid is transmitted equally in all directions. Consequently, by creating mechanical pressure on the surface of the piston of a small cylinder, a greater pressure is transmitted to the piston of a larger cylinder. Due to this, it moves upward with a force, which will be defined as the product of the fluid pressure and the area of this piston.

According to this scheme, the force that a large piston can overcome will be equal to the force applied to the small piston multiplied by the ratio of the area of the larger piston to the small one. The greater the difference in size between the small and large pistons, the greater the amplification factor for the hydraulic lever . To increase the power of the structure, two reverse-acting valves and a barrel of working fluid can be added. In this way, you get the simplest hydraulic jack.

In simple words: under the action of the pump, the oil enters the small cylinder, moves under pressure into the cylinder of the lifting mechanism and the load rises higher.

Use and maintenance

A possible reason for the breakdown is worn cuffs (when buying a new device, spare ones are included). The bypass valve may also fail. Oil is poured into a special hole to its level, the hole is located on the side of the jack body . During the operation of the jack, the amount of oil naturally decreases, so it must be replenished. There may also be a problem with the seals and oil seals - replacing them can fix the problem.

If there was an oil leak, excess air may appear in the cylinder, which is likely. For repairs in this situation, you need to open the oil tank and pump it without load, in "idle". NS Repeat this procedure until air is displaced.

Considering that metal parts corrode, remember to clean the internal valves and stems using kerosene or a special anti-corrosion fluid.

Any technique requires care and control. Safety directly depends on the serviceability of mechanisms and precautions.

Varieties

There is a wide range of devices to choose from.

Pneumatic, movable

The load is lifted by the method of air pressure on the air tank.

Rack jack

This is a simple and convenient tool, which is produced in a wide price range, and is designed for weights from 1.5 to 15 tons. There are 2 types of rack jack.

• toothed, working in the interaction of the handle and gears, is directly related to the height of the object's rise: the higher, the longer the main element of the device - the toothed rack;
• lever - raises and lowers loads using pressure on the lever.

Both types can be either manual or electric. Manual ones are convenient as a mobile option, electric ones are used in workshops, garages. When using rack and pinion jacks, you need to be extremely careful, as they are not sufficiently stable when the vehicle is lifted.

Screw jack

Designed for 1000 kg with a lifting height of 35 cm or 1500 kg with a lifting height of 39 cm.

Hydraulic telescopic jack (bottle type)

Carrying capacity from 2 to 20 tons. There are 9 options in the range of sizes (power) of jacks.

Selection Tips

The rolling jack can be connected to a compressor for air supply or to an exhaust pipe. But since the air cushions of the tank can be easily damaged, it is forbidden to carry out work without additional fasteners for the car raised with such a jack.

The rack and pinion jack can be used not only when replacing a wheel, but also when diagnosing a car or inspecting the bottom . Rack jacks are used in construction, on the railway and in other places of production. SUV drivers prefer to include powerful rack-and-pinion jacks in the vehicle, as they can be used to get out of the most difficult situations. For example: if you get stuck in snow or mud, or if a wheel falls into a hole.

A screw jack is suitable for a car. Do not confuse the lifting force of the jack with the weight of the vehicle. You do not need to lift the entire vehicle to replace a wheel. These jacks are divided into 2 types - with gasket and without gasket. The fact is that on the bottom of some cars there are special places where you can install a lift, but other models do not have such places, so it is better to choose a jack with a gasket so as not to damage the bottom of the car.

If you do not have the opportunity to see and check the availability of a special place, then it is better to choose with a gasket, for reliability . The jack is made of very strong steel, it can be subjected to high external forces. For example, in case of a fall from a great height or if a car accidentally passes over it, the jack will remain intact and in working order due to its stability, high-quality construction.

When working with large equipment, hydraulics are indispensable. Such powerful devices are suitable for cars, starting with jeeps and further to increase the mass of equipment . (tractor, freight transport, bus).

There is one point: if you purchased a jack for your jeep weighing 2 tons, and the manufacturer gives a plus 25% of the weight, but they want to borrow it, for example, for a truck weighing 6 tons, then it is better to refuse. The jack will withstand, but the weight limiting system may work, it will allow work to be done.

Where are they used?

A rolling jack is an integral attribute of any service station (service station). It is necessary for work in the garage in order to perform work with lifting not only the wheels, but also parts of the car. The lifting capacity of such jacks is standard for a passenger car of category B (B) - 2 tons . Lifting height - from 32 to 40 cm. In the process of lifting, the jack, which is installed on wheels, rolls under the car, the higher - the deeper, it is installed strictly vertically, maintaining balance.

Means, when choosing a lift for your car, you need to take into account its weight . For a passenger car, a screw and a hydraulic version is suitable, and from a jeep to a minibus, an exclusively hydraulic jack is needed.

It is more convenient to use trolleys permanently . They are larger than hydraulic ones.

When buying a car, a jack is already included in the package, which meets the requirements of this transport.