GB2365906A

GB2365906A - Non-impact pile driver

Info

Publication number: GB2365906A
Application number: GB0119597A
Authority: GB
Inventors: Shu Tong Siu
Original assignee: Individual
Current assignee: Individual
Priority date: 2000-08-11
Filing date: 2001-08-10
Publication date: 2002-02-27
Anticipated expiration: 2021-08-10
Also published as: CN2479064Y; HK1027264A2; CN1337500A; JP2002061186A; GB2365906B; GB0117890D0; GB0119597D0; CN1307347C

Abstract

A pile driver is constructed with a piling platform (4) mounted on a frame, where the piling platform (4) has a through hole for receiving a pile. The piling platform (4) consists of at least two pile clamping cylinder assemblies (fig 3a) and at least two hydraulic piling cylinder assemblies (4-1, 4-2, fig 4) which can be used either synchronously or asynchronously depending on the piling pressure that is required. The whole weight of the pile driver is directly connected to an oil hydraulic system so that the force exerted on the pile can be measured. The pile driver can move in a transverse or longitudinal direction and may include an operator cab (1) mounted on the frame and a hoisting machine (5) for lifting the piles into position.

Description

<Desc/Clms Page number 1> Hydraulic Pile Driver The present invention relates to a construction machine, and in particular to a pile driver.

Prior art pile drivers used in construction machinery are generally ram pile drivers which strike the pile into the ground with a ram head. Such pile drivers are very noisy and so are environmentally undesirable. Moreover", with prior art piling drivers, the piling quality is difficult to measure, as few loading data born by the pile are obtained during the piling process.

The objective of the present invention is to provide a new type of pile driver for the construction industry. The pile driver of the invention has little shake, low noise, safe and steady performance, credible piling quality and good mobility, and provides timely loading data. In addition, the frame structure of the pile driver is easily assembled and disassembled, and is easily transported.

According to a first aspect, the present invention provides a pile driver comprising: means for moving. the pile driver in a transverse and/or a longitudinal direction; a main frame; an oil hydraulic system; an electric system; and a piling platform mounted centrally on the main frame, the piling platform comprising: a central through-hole for receiving a pile in use; a clamping cylinder assembly to clamp a pile in place in use; and a piling cylinder assembly to push a pile into the ground under hydraulic pressure when clamped in use, wherein the pile driver comprises at least two

clamping cylinder assemblies and at least two piling cylinder assemblies such that said piling and clamping cylinder assemblies can be used asynchronously or synchronously depending on the piling pressure required, and wherein the whole weight of the pile driver is directly connected to the oil hydraulic system so that in use the force exerted on a pile can be measured.

At least in its preferred embodiments, the hydraulic pile driver of the present invention provides the following advantages: 1. The pile driver does not shake or emit exhaust gas and makes low noise during the operation process, thus it is less harmful to areas surrounding a construction site than-prior art pile drivers. Preferably, the noise level produced by the pile driver is less than 90dB.

2. Safe and steady performance: during the construction process, H-shaped or other steel piles can be directly and accurately positioned at the piling position by a hoist mechanism, then vertically clamped by the clamping cylinder assembly and pressed down into the ground smoothly by the pile driver until the designed bearing requirement of the pile is met.

3. Credible quality: during the construction process, two pairs of fixing clamps clamp respective upper and lower portions of a pile and keep the pile aligned in the desired piling position; in addition, detailed loading data of the oil pressure in the pile driver is read throughout the piling process, and this can greatly increase the success rate of piling.

4. High efficiency: 180 to 300 meter long H-steel piles may be pressed down into the ground within an 8- hour working day by the pile driver of the invention, so that the efficiency of the process is greatly improved. This is particularly true for large-scale construction.

5. Flexible structure: The pile driver of the invention is easy to assemble, disassemble and move, and

the clamps can conveniently be changed for different piles such as sheet piles, channel steel piles, square hollow section piles and circular hollow section piles as shown in figure 16 and figure 17.

Preferred embodiments of the invention will now be described, by way of example only, and with reference to the accompanying drawings in which: Figure 1 is a side view of a pile driver according to the present invention showing the whole structure thereof; Figure 2 is a top view of the pile driver of Figure 1; Figure 3 shows the manner of operation of the clamps of the pile driver of the present invention. Figure 4 is a front view of the piling platform of the pile driver of Figure 1; Figure 5 is a top view of the piling platform of the pile driver of Figure 1; Figure 6, figure 7 and Figure 8 show the structure of the elevating mechanism of the pile driver of Figure 1; Figure 9 shows a three-point pile-locating method used in an operation process according to the present invention; Figure 10 shows two piling methods used by the pile driver of the present invention; Figure 11 shows the sequence of movements of the longitudinal motion mechanism and the transverse motion mechanism of a pile driver according to the present invention; Figure 12 shows the oil hydraulic system of a pile driver according to the present invention; Figure 13 shows the hoisting machine oil hydraulic system of a pile driver according to the present invention; Figure 14 shows the electric system of a pile driver according to the present invention;

Figure 15 shows the operation panel of a pile driver according to the present invention; Figure 16 shows the fixing jaws of a pile driver according to the present invention for use with a square hollow section pile; and Figure 17 shows fixing jaws for use with a circular hollow section pile in a pile driver according to the present invention.

Figure 1 is a front view showing the main structure of a pile driver according to the invention, and Figure 2 is a top view of the pile driver of Figure 1. The pile driver comprises an operator cab 1, a body of the pile driver 3, a piling platform 4, a hoisting machine 5, a pair of long hulls 6, and a pair of short hulls 77 which together form longitudinal and transverse motion mechanisms for allowing longitudinal and/or transverse movement of the pile driver, an elevating mechanism 8, an oil hydraulic system 9, a balance weight 11 and an unshown electrical system. The operator cab 1 is the working place of the operator. The main component of the oil hydraulic system 9 is located below the operator cab 1. The body 3 of the pile driver is located above the short hulls in the. middle part of the pile driver. The piling platform 4 is mounted on the body 3 of the pile driver. As is shown by Figure 2, the piling platform 4 is also located in the middle part of the pile driver and is the most important component for the piling operation. Figure 1 also shows a hoisting machine 5 which as shown is provided with a second operator's cab. Figure 2 shows the chain wheels of the pile driver and the operator cab of the hoisting machine 5 which is used to place a pile into a hole in the middle of the piling platform 4. The two long hulls 6 are located under either side of the pile driver, and each long hull is mounted to a longitudinal motion cylinder to cause the components of piling platform 4 to move

longitudinally. The two short hulls 77 are located between the two long hulls, and each short hull is mounted by a transverse motion cylinder which provides the functions of rotation and transverse movement. Figure 11 shows the steps in the movement of the long hulls and short hulls. An elevating mechanism 8 is located on the top of the long hulls for moving the pile driver body 3, elevating the long hulls and short hulls and adjusting the level and balance of the pile driver body 3. A balance weight 11 is provided on either side of the body 3, which increases the weight of the pile driver body so as to keep the pile driver steady and increase piling pressure applied to a pile in use.

The piling platform 4 is an especially important component of the pile driver of the present invention. Figure 3 shows the way in which a pile is clamped before the piling operation using the pile driver of the present invention. The pile shown in Figure 3 is an H- shaped steel pile. The H-shaped steel pile is lowered by the hoisting machine 5 into the right position and passes through the through-hole of the piling platform. The lower end of the pile touches the ground, and two pairs of clamps of a clamping cylinder assembly 4-8 arranged at 90 to one another and each including first and second clamping surfaces arranged opposite one another move inwardly so as to clamp the H-shaped pile (as is shown by Figure 3a), and then the piling cylinder assembly presses the pile down into the ground (as is shown by Figure 3b). The particular character of the invention lies in the fact that it provides a static piling operation by pressing clamped piles down with a piling cylinder assembly.

Figure 4 and Figure 5 show the piling platform 4 and its directly relevant parts of the pile driver according to the present invention. Figure 4 shows a front view of the platform and Figure 5 is a top view thereof. The piling platform 4 comprises main piling

cylinders 4-1, subsidiary piling cylinders 4-2, concave ball seats 4-3 and protruding ball seats 4-4 which together provide a flexible connection between the hydraulic jacks of the piling cylinders and the hulls of the pile driver and which allow slight rotational movement to keep the whole pile driver in balance, clamping apparatus 4-5.1,4-5.2, clamping cylinders 4-6, fixing jaws 4-8, movable jaws seats 4-9, a body 3 and guide wheels 17. As an example, the pile 51 shown in the drawings is an H-shaped steel one. The clamping cylinders clamp the pile along the radial direction, that is to say when the pile is pressed vertically down to the ground, the clamping cylinders will clamp the pile in the horizontal direction. The structure of this part is described from the centre outwards as follows: the fixing jaws 4-8 clamp the pile 51; the clamping cylinders 4-6 push the movable jaws seats 4-9 which push the fixing jaws 4-8; the clamping apparatus 4-5.1,4-5.2 provides oil and forms a part of oil circuit. The above mentioned components form a whole apparatus to clamp the pile 51 and are adjusted by guide wheels 17 towards the desired position. In the piling operation process, the main piling cylinders 4-1 and/or the subsidiary piling cylinders 4-2 press the pile down, and the concave ball seats 4-3 and protruding ball seats 4-4 keep the pressure balanced. The location of the body 3 of the pile driver in the pile driver is shown in Figure 1 and Figure 2.

The piling platform 4 shown in the drawings has two sets of clamping cylinder assemblies 4-5.1,4-5.2. Each set is made up of four cross-located clamping cylinders 4-6, having four fixing jaws 4-8 which are used to fix the pile. The provision of an upper clamping cylinder assembly 4-5.1 and a lower clamping cylinder assembly 4- 5.2 as in the piling platform shown in the drawings speeds up the piling operation. In addition, the clamping cylinders and piling cylinders are separately

located. The piling cylinder assembly comprises two main piling cylinders and two subsidiary piling cylinders. The piling platform may achieve both asynchronous and synchronous piling operations or achieve a piling operation to install an inclined pile. These are features enjoyed only by pile drivers according to the present invention.

The operation process of the piling platform 4 is described as follows: The piling platform is the main working component of the pile driver which performs the clamping operation and the piling operation. The structure of the piling platform is described as above, and mainly comprises the main and subsidiary piling cylinders, the piling apparatus and the clamping cylinder assemblies.

At first, the main piling cylinders retract and lift the piling apparatus to its highest place. Then an H-shaped steel pile is put into the clamping apparatus and clamped by the four clamping cylinders (Figure 3).

A piling valve is controlled to then drive the main piling cylinders to move downwards and press the pile into the ground. Meanwhile, the subsidiary piling cylinders move upwards. When the main piling cylinders have moved down as far as possible, the clamping cylinders thereof release the pile. Then the subsidiary piling cylinders clamp the pile and press it down into the ground until they reach the end of their cycle. The main piling cylinders and subsidiary piling cylinders alternately press the pile until the whole pile is pressed into the right depth in the ground.

When the required piling force to drive the pile into the ground is over 3000kN, a piling force- increasing valve is operated after the piling oil pressure has reached 20Mpa so as to make the pistons of the subsidiary piling cylinder extend and press on the clamping seats of the piling apparatus. Thus, the main piling cylinders and the subsidiary cylinders will work

together and enable the piling force to reach 6000kN or more.

Figure 6, Figure 7 and Figure 8 show the structure of the elevating displacement mechanism of the pile driver of the present invention. In comparison with Figure 1 and Figure 2, the balance weight, the operator cab and the hoisting machine etc are not shown, in order to better explain the mutual relation among the components of the elevating displacement mechanism. Figure 6 is a front view, Figure 7 is a top view, and Figure 8 is a side view. The elevating mechanism mainly includes elevating hydraulic cylinders 14 and two beams 13. One end of each beam is hinged with the body 3 of the pile driver, while the other end is mounted on an elevating cylinder 14. The piston rod of elevating cylinder 14 is hinged with four stepping wheel carriers. When the piston rod extends in one direction or the other, the body will be lifted up, or brought down.

The long hulls 6 are two rectangular components that are respectively located on opposite sides of the pile driver. Each long hull has a longitudinal motion cylinder 6-1 which retracts in or extends out so as to cause the stepping wheel carriers 6-2 and beams to move along in the longitudinal direction via linkage cylinders 6-3. As a result, the short hulls 77 also move along in the longitudinal direction. Each short hull 77 has a transverse motion cylinder 78 pushing the short hull to move transversely along the beams 13. A turntable platform 75 is located on the short hulls 77 and the body with the elevating cylinders 14 is located above the turntable platform. The elevating cylinders 14 drive the long hulls and the short hulls up and down. A central axle 73 is located at the center of the turntable platform 75, this enables the turntable platform 75 to perform rotary motion easily. There are restoring springs 74 located inside the turntable platform 75 and restoring seats 15 under the pile driver

body 3 so as to position the body.

In addition, the performance of the long-hull longitudinal motion mechanism, the short-hull transverse motion mechanism and the rotational motion mechanism may be summed up as follows with reference to Figure 1, Figure 2, Figure 6 and Figure 8.

The longitudinal motion mechanism will be described first. As shown in the drawings, the longitudinal motion mechanism is mainly made up of moving wheel carriers, longitudinal motion cylinders 6-1 and long hulls 6. The pistons of the longitudinal motion cylinders are hinged with the two long hulls, while the longitudinal motion cylinder bodies are hinged with the moving wheel carriers. When the cylinder pistons extend or retract, there is a relative longitudinal movement between the body 3 of the pile driver and the long hulls 6. The transverse motion mechanism and the rotation mechanism will now be described. As shown in the drawings, the transverse 7 and rotation motion mechanisms are mainly made up of a turntable 75, stepping wheel carriers, two short hulls 77, transverse motion cylinders 78, central shafts and restoring springs 74. Two central shafts and four restoring springs are fixed to the body 3 of the pile driver. The turntable, 4 sets of stepping wheel carriers hinged with the turntable and the two short hulls are hung on the central shafts and can rotate against the central shafts. When two of the transverse motion cylinder pistons extend or retract together, there is a relative transverse movement between the body 3 of the pile driver and the turntable. When one cylinder piston extends while the other retracts, there is a relative rotation between the body 3 of the pile driver and the turntable to reach a desired rotary angle.

When the short hulls leave the ground surface after the relative rotation of the pile driver body and the

turntable, the pile drive body can be returned to the middle position approximately by activating the restoring springs mounted on the turntable to pull the turntable back to its original position relative to the short hulls.

Figure 9 shows the sequence of events when positioning a pile by means of a three-point method. The foundations of a building are a very important aspect of its construction, so the position of each pile in the building should not deviate from the designed location. In order to make sure that the piles are pressed into the ground at the correct location, the pile driver of the present invention, besides having a leveller adopts a "three-point defining a line" method to ensure that the piles can be pressed down into the ground exactly vertically when required. As is shown in Figure 9, two of the three points on the line are determined by the two sets of clamping cylinder assemblies, and the third point is determined when the pile touches the ground. Thus, the pile can be pressed vertically and steadily into the ground.

Figure 10 shows two alternative piling methods which can be achieved by the pile driver of the present invention, namely a synchronous piling method and an asynchronous piling method. These methods are distinguishable from others. As is shown in Figure 10, the upper clamping apparatus 4-51 and the lower clamping apparatus 4-52 can work either separately or together to press a pile into the ground.

The following is a description of the asynchronous piling method. At the beginning, the upper and lower clamping apparatuses 4-5.1 and 4-5.2 both clamp the pile to press it into the ground. When the pressed pile reaches a certain depth, the two clamping apparatuses release the pile and move to the middle of the remaining exposed part of the pile at the same time as shown in Figure 10-b. Then, the lower clamping apparatus 4-5.2

clamps the pile to press it down, while the upper clamping apparatus 4-5.1 moves upward as shown in Figure 10-c. When the clamping cylinders of the lower clamping apparatus reach their end point of travel, the lower clamping apparatus will open and the upper clamping apparatus clamps the pile and presses it down as shown in Figure 10-d. Simultaneously, the lower clamping apparatus moves upward-to the middle of the remaining exposed part of the pile and repeats the above-mentioned steps. While the lower segment of a pile is being pressed into the ground, the force borne by the pile driver is less than 3000kN, and at this time, the two clamping apparatuses work separately. In this way, the alternate operation of the two clamping apparatuses can be implemented to speed up piling and elevate the efficiency thereof while producing the pressure of a single clamping apparatus. It will of course be understood that the method of asynchronous piling described can be improved to extend to the operation of more than two clamping apparatuses.

The force required to press the remaining upper segment of a pile into the ground is however greater than 3000kN. Thus, for this part of the piling operation, the two clamping apparatuses work together to meet the desired piling load so as to ensure that each pile has the same carrying capability. Thus, in this part of the piling operation, the upper and lower clamping apparatus work synchronously.

Another feature of the pile driver of the invention lies in that the pile driver may put in a pile at up to a 5 oblique angle, so as to pile an inclined pile having an oblique angle to meet some special requirements.

In order to learn the piling situation of the pile driver clearly, the pile driver is provided with measurement equipment to measure piling pressure and piling depth during the piling operation. It is thus

possible to not only improve the success rate of piling compared to prior art processes but to know the practical carrying capability and exact location of every pile once in situ. The net weight of the pile driver is 660 tons. This can be increased to a maximum of 700 tons by adding counter weights so as to reach testing load completely.

Since there is a direct relation between the structure and the oil meter of the pile driver, it is possible to directly check and measure the carrying capability of the pile at any moment without any other oil meter being added. The piling platform shows the piling pressure and will keep the pressure at a desired value for a period. If the pile goes into the ground within a desired range of pressure and within a desired time, the piling check is completed.

Figure 11 shows the relative movement possible between the long hulls and short hulls of the pile driver of the present invention. There are three possible movements: fore and aft movement, left and right movement and rotational movement against the central shaft. Each pile driver has two long hulls 6 and two short hulls 77 as discussed above. In Figure 11, the narrow rectangles represent long hulls 6 and the short rectangles represent short hulls 77. Each situation is shown in top view (11a, 11c and 11e) and side view (11b, 11d and 11f) in Figure 11.

Relative fore and aft movement between long hull 6 and short hull 77 is shown in Figures 11a and 11b. The long hulls 6 are lifted off the ground by the elevating cylinders 14 and then pushed by longitudinal motion cylinders 6-1 to move forward. When the longitudinal motion cylinders reach their maximum range or predetermined distance, the long hulls will fall down (as shown at ii) until the short hulls are lifted off the ground and pushed to move forward. When the transverse motion cylinders reach their maximum range or

predetermined distance (as shown at iii), the short hulls will fall down, and the long hulls are lifted off the ground to start the above cycle of steps again. Thus, the continual movement of the long hulls and the short hulls through the above cycle makes them move forward or rearward. The movement method is distinguishable from that of known pile drivers.

Relative left and right movement is shown in Figures 11c and 11d. The method is similar to the fore and aft movement mentioned above.

The elevating cylinders 14 retract to lower the body 3 of the pile driver, and the long hulls 6 are lifted off the ground while the short hulls 77 fall back to the ground. The transverse motion cylinders 78 then extend and drag the wheel carriers as well as the turntable 75 rightwards or leftwards until the transverse motion cylinders reach their limit. The elevating cylinders then extend to lift the body 3 and the long hulls 6 fall back to the ground while the short hulls are lifted off the ground. Meanwhile the transverse motion cylinders extend and push the short hulls to move upwardly until the transverse motion cylinders reach their limit. Then the elevating cylinders retract to lower the body of the pile driver and the long hulls 6 are once again lifted off the ground and the cycle is repeated.

Relative rotation movement against the central shaft is shown in Figures 11e and 11f. At first, the transverse motion cylinders extend or retract to a midway point simultaneously, then the following steps are carried out: The elevating cylinders 14 retract back and then the long hulls 6 are lifted off the ground while the short hulls 77 fall back to the ground. Next the left transverse motion cylinders 78 extend while the right ones retract so as to push the body to turn through an angle of about 8 clockwise. Then the elevating

cylinders 14 extend so the long hulls 6 fall back to the ground while the short hulls 77 are lifted off the ground. Meanwhile the right transverse motion cylinders extend while the left ones retract so as to push the turntable to turn through an angle of about 8 anticlockwise. The elevating cylinders then retract back and again lift the long hulls off the ground while the short hulls fall down to the ground. Once the desired angle is reached, the short hulls return back to their original positions.

To do this, the elevating cylinders extend and then the long hulls fall down to the ground while the short hulls are lifted off the ground. The short hulls return back to their midposition by the action of the restoring spring pushing the turntable.

In order to meet a variety of requirements according to different topography and piling positions, the machine may turn through a required angle. Although the rotational range is limited to only 8 each time, it is enough to meet most requirements of engineering. The rotation is achieved by rotating the short hulls 77 about the centre of the machine in either the clockwise or anticlockwise direction as shown at ii) and iii) respectively and described above.

Since relative movement between the long hulls and the short hulls is possible, the pile driver has a broader practicability than pile drivers of the prior art. The movement and the elevation of the pile driver of the present invention are carried out by cooperation of the specific structure and the hydraulic cylinders. The long hulls 6 are lifted off the ground by the elevating cylinders 14 and driven by longitudinal motion cylinders 6-1 to move forward or rearward; similarly, the short hulls 77 are lifted off the ground by the elevating cylinders 14. and driven by transverse motion cylinders 78 to move leftwards of rightwards. The short

hulls are lifted off the ground as above and turned through a certain angle by means of the transverse motion cylinders 78.

Figure 12 shows the circuit of an oil hydraulic system of the pile driver of the present invention. The system mainly includes:

D Electromotor E1 to EQ Selector valve F1 Overflow valve P Oil pump H1 to HZ Selector valve Fz to F, Electromagnetic PI to P9 Selector valve A,B,C,D Cylinders reversal valve The principle of the system is shown in Figure 12. A variable double pump provides oil and the overflow valve Fl keeps the pressure at 20Mpa.

The selector valves El to E41 Hl to HZ and Pl to P4 are separately responsible for the longitudinal movement, the transverse movement, the piling operation, the clamping operation and the elevating operation.

They are divided into four groups, including longitudinal/ transverse motion cylinder assemblies made up of two transverse motion cylinders and two longitudinal motion cylinders in this embodiment; a piling cylinder assembly made up of two main piling cylinders and two subsidiary piling cylinders; a clamping cylinder assembly made up of eight clamping cylinders; and an elevating cylinder assembly made up of four elevating cylinders. The oil pump presses the oil to flow from the final oil cylinder into the oil pipes and relevant controlling valves to control these cylinders to extend or retract. All components are shown in Figure 12, the person skilled in the art can understand the controlling system and the oil channels of the pile driver from Figure 12.

Figure 13 shows the oil hydraulic system of the hoisting machine 5 of the pile driver of the present invention. The oil hydraulic system shown in Figure 13

is a separate system from the main oil hydraulic system and belongs to the hoisting machine 5 shown in Figure 1 and Figure 2. The oil hydraulic system shown in Figure 13 has a different working range from that in Figure 12. During the piling process, the pile should be moved to the predetermined place with the hoisting machine, to weld the pile and then to start the piling operation. The pile driver has a hoisting machine with hoisting capability of 12 tons so as to complete hoisting, welding and piling operations rapidly by the pile driver itself.

The principle of the oil-pressure controlling system is shown by Figure 13. A variable pump provides the oil, and overflow valves 3 in selector valves keep the oil pressure at 20Mpa.

A manual selector valve is responsible for changing the piling pressure, and controlling the oil flow rate. The oil-pressure controlling system mainly comprises an oil filter 13-1, an electromotor 13-2, an oil pump 13-3, selector valves 13-4, a manual selector valve 13-5, balance valves 13-6, a motor for moving the beams 13-7, a hoisting hydro motor 13-8, a one-way block valve 13-9, an oil-pressure motor for rotation 13-10, a duodirectional cushion valve 13-11, oil cylinders 13-12, an oil manometer 13-13 and an oil-returning filter 13- 14.

Figure 14 shows the piling electrical system of the pile driver of the present invention. As is shown by Figure 4, the piling electrical system comprises two main electric motors 1D and 2D, a plurality of AC contactors, a plurality of breakers, a controlling transformer, an automatic switch, a control button, various plug seats, etc. The components are listed as follows:

Name Mark Name Mark Automatic switch K Main switch 1-4K Current transformer H Stop button TA,TA2 Current meter A Start button QAIQA2 Voltmeter V Lock button TK AC contacter KM1KM2 Top lamp ZD,ZD2 AC contacter KM2 Metal haloid ZD3 flood light AC contacter KMIKM3 AC contacter KM6 Signal lamp XD, XD2 XD3 Intermediate relay 1ZJ-3ZJ Signal lamp XD3 XD3 Thermo-relate 1JR 2JR Trinomial ZC1 fore-wire plug Control transformer KB, Breaker 1QF 2QF Monomial ZC2 three-wire plug Breaker 3QF 4QF Breaker 5QF Monomial two- ZC3 wire plug Breaker 6QF Breaker 7QF Phase converter JX Breaker 8-IOQF Figure 15 shows the operation panel of the pile driver of the present patent. Although the pile driver has a number of cylinders and electric components, the operation panel is not complex, and includes three sets of handles H1 and H2, E1 to E4 and P1 to P4 and five buttons. An operator may control the whole system by following the below listed process.

1) Starting up: turning on the air switch and then the power switch, and putting the handles of all selector valves in midposition; pressing down the left pump button and the right pump button after eight seconds; pushing the handle H2 to the position of "releasing pile" after three-minute no-load running without abnormal phenomenon; watching whether the

operation panel shows that the oil pressure of the system increases by a desired 20Mpa then pushing the handle H2 back to its midposition.

2) Positioning: operating the four stepping handles E1 to E4 together with the four elevating handles P1 to P4 to move the pile driver longitudinally or transversally so as to find the right piling position.

3) Levelling: operating the four elevating handles P1 to P4 and observing whether the omnibearing levelmeter on the operation panel stays zero to level the pile driver before piling, in order to make sure that the piles are positioned perpendicular to the ground surface.

When there is no limitation to height, the pile driver is able to press down a variety of piles with different length (such as a 12-meter pile, 24-meter one, 36-meter one or longer one) to make them reach a desired depth rapidly.

The pile driver itself weights 600 tons, so it is hard to transport from one building site to another. Therefore, the pile driver may be disassembled before it is transported from one place to another. The pile driver comprises two long hulls 6, two short hulls 77, four beams 13, a hoisting machine 5, a main operation platform 3 and a number of heavy fittings 11. Since the structure of the pile driver is not complex, it is easy to assemble or disassemble the machine rapidly.

Figure 16 shows the piling platform 4 in the clamping state when the pile driver of the present invention is piling the pile. The shape of the fixing jaws 4-8 of the pile driver may be changed accordingly to fit the different sections of different types of pile. In this example, the front surface of the fixing jaw 4-8 is flat.

In Figure 17, the section 6 of the pile is circular, so the front surface of fixing jaw 4-8 is a

concave curved surface so as to match with the surface of the pile.

Some data relating to a preferred embodiment of the pile driver of the present invention is given below: 1. External dimensions (length x width x height) Working state (m) 14 x 8.2 x 22 Transport state (the biggest component m) 14.8 x 3.4 x 3 2. Piling capability The largest piling capability (kN) 6000 Piling speed (m/min) 2 (quick speed) 1 (small speed) The shortest distance between center of piling position and side of the pile driver (m) 4.1 3. Size of pile (length x width) H-shaped steel pile (m) 0.3 x 0.3 to 0.5 x 0.5 Length of single pile (m) 2.5 to 12 Length of welded pile (m) >60 4. Stepping capability Stepping speed of long hull and short hull (m/min) 2.5 to 5 Stepping course of long hull (m) 3.6 Stepping course of short hull (m) 0.8 Grounding pressure of long hull (Mpa) 0.13 Grounding pressure of short hull (Mpa) 0.14 Turning angle each rotation s8 5. Hoisting machine Hoisting capability (t) < _ 12 Effect hoisting height (m) 18 Hoisting moment (kN.m) 600 Hoisting speed (m/min) 8.5 Rotation speed (r/min) 0.6

6. Further data Net weight of the pile driver (t) 150 Balanced weight (t) 450 Weight of the largest component (t) 36 Limited working pressure of oil pressure system (Mpa) 20 ' Power capability of electric motor (kw) 105 The embodiments described above is an illustrative example only of a pile driver according to the present invention. The invention claimed may take various different forms according to different practical needs and the scope of the invention is limited only by the appended claims.

Claims

Claims 1. A pile driver comprising: means for moving the pile driver in a transverse and/or a longitudinal direction; a main frame; an oil hydraulic system; an electric system; and a piling platform mounted centrally on the main frame, the piling platform comprising: a central through-hole for receiving a pile in use; a clamping cylinder assembly to clamp a pile in place in use; and a piling cylinder assembly to push a pile into the ground under hydraulic pressure when clamped in use, wherein the pile driver comprises at least two clamping cylinder assemblies and at least two piling cylinder assemblies such that said piling and clamping cylinder assemblies can be used asynchronously or synchronously depending on the piling pressure required, and wherein the whole weight of the pile driver is directly connected to the oil hydraulic system so that in use the force exerted on a pile can be measured.
2. A pile driver as claimed in claim 1, further comprising an operator cab mounted on said main frame.
3. A pile driver as claimed in claim 1 or 2, wherein said main frame comprises: a pair of parallel spaced apart long hulls and a plurality of short hulls arranged in between the pair of long hulls, the said long and short hulls being connected to one another to form said main frame in such a way as to allow longitudinal and/or transverse motion of the pile driver.

<Desc/Clms Page number 22>
4. A pile driver as claimed in claim 3, wherein the long hulls and short hulls are connected to one another by beams.
5. A pile driver as claimed in any preceding claim, wherein the clamping cylinders are arranged so as to clamp a pile in use substantially perpendicular to the longitudinal axis thereof.
6. A pile driver as claimed in any preceding claim, wherein each clamping cylinder assembly is made up of four clamping cylinders arranged to extend at right angles to one another.-
7. A pile driver as claimed in any preceding claim, wherein the pile driver comprises a first said clamping cylinder assembly and a second said clamping cylinder assembly and wherein the first clamping cylinder assembly is located above the second clamping cylinder assembly.
8. A pile driver as claimed in any preceding claim, wherein each said piling cylinder assembly comprises either two or four piling cylinders.
9. A pile driver as claimed in any preceding claim, wherein the pile driver comprises only two piling cylinder assemblies.
10. A pile driver as claimed in any of claims 3 to 9, wherein the pile driver further comprises an elevating cylinder assembly for elevating the long hulls and/or the short hulls to enable the pile driver to move in a longitudinal or transverse direction or to rotate without overbalancing.

<Desc/Clms Page number 23>
11. A pile driver as claimed in claim 10, wherein the elevating cylinder assembly comprises four elevating cylinders.
12. A pile driver as claimed in any of claims 3 to 11, the pile driver further comprising a body located above the short hulls, wherein the piling platform is mounted on the body.
13. A pile driver as claimed in any of claims 3 to 12, wherein a longitudinal motion cylinder is provided on each said long hull.
14. A pile driver as claimed in any of claims 3 to 13, wherein the main frame comprises two short hulls each of which is provided with a transverse motion cylinder.
15. A pile driver as claimed in any of claims 3 to 14, the piling platform further comprising concave ball seats and protruding ball seats which together provide a flexible connection between the piling cylinder assemblies and the hulls of the pile driver and which allow slight rotational movement to keep the whole pile driver in balance.
16. A pile driver as claimed in any preceding claim, further comprising a balance weight for increasing the weight on a driven pile during the piling process.
17. A pile driver as claimed in any preceding claim, further comprising a hoisting machine for lifting piles into position for piling.
18. A pile driver as claimed in any of claims 8 to 16, wherein the elevating cylinder assembly may be positioned at an angle of between 0 and 5 to the vertical depending on the angle at which a pile is to be

<Desc/Clms Page number 24>

inserted.
19. A pile driver as claimed in any preceding claim, wherein the pile driver is H-shaped so as to correspond to longitudinal -transverse line positions in construction engineering, to make it convenient to transport the machine and to carry out building and so that in use the machine is located and moved along longitudinal and transverse lines.
20. A pile driver as claimed in any preceding claim, wherein the pile driver may be disassembled and reassembled easily to aid in transportation thereof.
21. A pile driver as claimed in any preceding claim, wherein the two clamping cylinder assemblies are arranged one above the other such that in use a pile may be held vertically at three points along a line defined respectively by the first and second clamping cylinder assemblies and the point at which the pile contacts the ground.
22. A pile driver as claimed in any preceding claim, wherein the clamping cylinder assemblies comprise fixing jaws and the shape of the jaws is altered depending on the shape of pile to be installed.
23. A pile driver as claimed in claim 22, wherein the fixing jaws have a flat contact surface for clamping H- shaped or square hollow section piles.
24. A pile driver as claimed in claim 22, wherein the fixing jaws have a concave arched surface for clamping circular hollow section piles.
25. A pile driver as claimed in any preceding claim, wherein the pile driver may perform either an

<Desc/Clms Page number 25>

asynchronous piling operating or a synchronous piling operation such that during the asynchronous piling operation a first clamping cylinder assembly and a first piling cylinder assembly work alternately with a second clamping cylinder assembly and a second piling cylinder assembly, and during the synchronous piling operation the first clamping cylinder assembly and the first piling cylinder assembly work synchronously together with the second clamping cylinder assembly and the second piling cylinder assembly to press a pile down into the ground under a greater pressure than that produced by the asynchronous piling operation.
26. A pile driver as claimed in claim 25, wherein in use a pile is inserted into the ground by initially using the asynchronous piling operation and then, when the pile reaches a certain depth in the ground at which a greater piling pressure is required, the synchronous piling operation is used.
27. A pile driver substantially as herein described with reference to the accompanying drawings.