The Simulation of Hydraulic Synchronous Lift of Heavy Loads

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Figure 2. The rotation of the Apollo Bridge [8]

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3.2. The Example of Usage Abroad

Another example of usage of the hydraulic lifting system is from abroad. In the USA, it is very popular to move entire houses. Also in this case, the relocation of such large, heavy and bulky object would be impossible without the use of hydraulic system. In America, houses are usually built of wood and their only concrete parts are the foundations. Therefore, it is easy to disconnect the wooden part (of the house) from the concrete base. The advantage of this moving is that the whole complex can be relocated to another place.

Figure 3. Relocation of a house [11]

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3.3. The Example of Synchronous Lift on Transport Communications

When it comes to transport communications, maintenance and repairs to the bridges are very important owing to the ever increasing traffic. Nowadays, the constructions of new bridges or repairs to them are carried out exclusively by hydraulics. Using hydraulics, bridge structures can be lifted but also let down or they can be manipulated with in some other way. The most common operation that is carried out when bridges are being lifted is the replacement of the bearings. In most cases, this operation is very easy but only if the bridge structure is not very complicated.

Figure 4. Replacement of a bridge structure

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Figure 5. Lift of a bridge in order to repair the bearings [10]

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Figure 6. Detail of the lift of a bridge [9]

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4. Arranging for the Synchronous Lift

Synchronous lift system components consist of a control unit, sensors and hydraulic equipment. The sensors achieve a high accuracy of measurement. Using the control unit, it is possible to change several settings as for example the setting of the initial “zero” position or the setting of the allowed regulation deviation. The regulation system is two-positional which means that each pressure output is controlled by the solenoid valve. The most commonly used is the regulation of fluid pressure of synchronous lift by solenoid valves. The high-pressure pump is one of the main components that comprise the system. The solenoid valves constitute the main part of this method. These valves are designed to regulate the flow and they consist of three basic components which are the connector, the valve body and the coil.

A scheme for 4 up to 64-point lift systems. This system is capable of controlling up to 64 lift points and it can be used with both single and double-acting hydraulic cylinders.

It is possible to program this system so that each hydraulic cylinder simultaneously performs a different lift.

Figure 7. A diagram of a 4-point synchronous lift system [12]

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Figure 8. Tilting performed by the programmed hydraulic cylinders [12]

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In hydraulic systems, lift height is controlled by sensors. These position sensors measure the coordinates of a particular point within the system.

5. Proposal for a Hydraulic System

Figure 9. A diagram designed in Matlab

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The aim of the proposal for a hydraulic system is to propose a system capable of providing synchronous lift of heavy loads. In order to maintain security, the proposed system should use a maximum of 80% of its power. Cylinders must be placed stably on smooth and flat surfaces. Load’s fulcrum must be stable and centered on the cylinder’s axis.

Figure 10. The resulting graphs that capture a 30 second spans using simulation

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