VIBRATORY PILE DRIVING APPARATUS

Abstract

The present invention relates to a vibratory pile driving apparatus for upending a pile and for driving a pile into the ground and/or extracting a pile out of the ground. The apparatus comprises a frame clement. a clamping device, attached to the frame clement at a first side thereof and configured to clamp the pile, at least one vibrator device. attached to the frame element at a second side, opposite to the first side, and configured to subject the frame element and the clamping device to a vibratory load. and a lifting yoke, rotatably connected to the frame element. The pile driving apparatus is configured to be suspended from a crane by the lifting yoke during use and the lifting yoke is configured to be rotated relative to the frame element to move the pile driving apparatus between a loading configuration and a pile driving configuration. The lifting yoke comprises one or more dampening elements, which are. during use. configured to deform to inhibit transmission of vibrations to the crane.

Claims

1. Vibratory pile driving apparatus for upending a pile and for driving a pile into the ground and/or extracting a pile out of the ground, the apparatus comprising: a frame element, a clamping device, attached to the frame element at a first side thereof and configured to clamp the pile, at least one vibrator device, attached to the frame element at a second side, opposite to the first side, and configured to subject the frame element and the clamping device to a vibratory load, and a lifting yoke, rotatably connected to the frame element, wherein the pile driving apparatus is configured to be suspended from a crane by the lifting yoke during use, wherein the lifting yoke is configured to be rotated relative to the frame element to move the pile driving apparatus between a loading configuration and a pile driving configuration, and wherein the lifting yoke comprises one or more dampening elements, which are, during use, configured to deform to inhibit transmission of vibrations to the crane.

2. Vibratory pile driving apparatus according to claim 1, wherein the one or more dampening elements are configured to deform in a vertical direction during use.

3. Vibratory pile driving apparatus according to claim 1, wherein the lifting yoke further comprises: a dynamic part, which is attached to the frame element, and a static part, with which the pile driving apparatus is configured to be suspended from the crane, and wherein the one or more dampening elements are functionally arranged in between the dynamic part and the static part, to inhibit transmission of vibrations from the dynamic part to the static part.

4. Vibratory pile driving apparatus according to claim 3, wherein the static part comprises a downward yoke arm, extending in a downward vertical direction, wherein the dynamic part comprises an upward yoke arm extending in a downward vertical direction, wherein the downward yoke arm and the upward yoke arm at least partially face each other to form a set of yoke arms, and wherein the one or more dampening elements are attached in between the downward yoke arm and the upward yoke arm.

5. Vibratory pile driving apparatus according to claim 4, each set of yoke arms comprising at least two downward yoke arms, wherein the upward yoke arm is arranged centrally in between the downward yoke arms and wherein the lifting yoke comprises at least one respective dampening element in between the central upward yoke arm and each of the downward yoke arms, or each set of yoke arms comprising at least two upward yoke arms, wherein the downward yoke arm is arranged centrally in between the upward yoke arms and wherein the lifting yoke comprises at least one respective dampening element in between the central downward yoke arm and each of the upward yoke arms.

6. Vibratory pile driving apparatus according to claim 4, wherein the static part further comprises a spreader bar, extending in a horizontal direction parallel to an axis of rotation between the lifting yoke and the frame element, and wherein opposed sideward sets of yoke arms are provided at opposite ends of the spreader bar, formed by the downward yoke arms that downwardly extend from the spreader bar and by the upward yoke arms that are arranged at opposite sides of the frame element.

7. Vibratory pile driving apparatus according to claim 6, wherein the lifting yoke further comprises a central set of downward yoke arms and upward yoke arms, which is located centrally in between the opposed sideward sets of yoke arms.

8. Vibratory pile driving apparatus according to claim 1, wherein the one or more dampening elements are made of an elastomeric material.

9. Vibratory pile driving apparatus according claim 1, wherein the one or more dampening elements are modular dampening cassettes, comprising a changeable number of dampers, which are deformable in parallel to each other.

10. Vibratory pile driving apparatus according to claim 1, wherein the frame element further comprises at least one hinge device, wherein the lifting yoke is attached to the frame element by means of the at least one hinge device.

11. Vibratory pile driving apparatus according to claim 10, further comprising an actuator which is attached to the frame element and the lifting yoke and which is configured to move the lifting yoke relative to the frame element between the loading configuration and the pile driving configuration.

12. Vibratory pile driving apparatus according to claim 1, wherein the lifting yoke further comprises a cable guiding device, configured to guide cables and/or hydraulic fluid lines departing from the pile driving apparatus.

13. Vibratory pile driving apparatus according to claim 1, wherein the frame element comprises a plurality of clamp mounting rails at its first side, wherein the clamp mounting rails extend in a radial direction relative to the vertical direction, wherein the clamping device comprise two or more clamps, which are attached to the clamp mounting rails to define a pile clamping pattern, between them, and wherein the clamps are slidable along the clamp mounting rails to adjust a dimension of the pile clamping pattern.

14. Vibratory pile driving apparatus according to claim 1, wherein the frame element comprises one or more vibrator mounting rails at its second side, and wherein the at least one vibrator device is attached to the vibrator mounting rails.

15. Vibratory pile driving apparatus according to claim 14, wherein the vibrator mounting rails extend in a horizontal direction perpendicular to the axis of rotation and wherein the at least one vibrator device is, at least in the loading configuration, arranged in between the opposed sets of yoke arms of the lifting yoke.

16. Method of driving a pile into the ground by means of the vibratory pile driving apparatus according to claim 1, comprising the steps of: clamping the pile by means of the clamping device, moving the pile to a location where it is to be driven in the ground, and subjecting the pile to vibrations with the at least one vibrator device.

17. Method according to claim 16, wherein the step of clamping is carried out with the pile driving apparatus in the loading configuration, wherein the method further comprises the step of upending of the pile from a horizontal orientation into a vertical orientation, prior to driving it into the ground, wherein the step of upending comprising lifting the pile driving apparatus and the pile and rotating the pile driving apparatus towards the pile driving configuration during the lifting, to bring the pile from the substantially horizontal orientation into the substantially vertical orientation.

18. Method of extracting a pile out of the ground by means of the vibratory pile driving apparatus according to claim 1, comprising the steps of: clamping the pile by means of the clamping device, subjecting the pile to vibrations from the at least one vibrator device, and pulling the pile in an upward vertical direction with the pile driving apparatus.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0122] Further characteristics of the invention will be explained below, with reference to embodiments, which are displayed in the appended drawings, in which:

[0123] FIG. 1 schematically depicts an embodiment of the vibratory pile driving apparatus according to the present invention, arranged in the pile driving configuration,

[0124] FIG. 2 depicts the vibratory pile driving apparatus of FIG. 1, arranged in the loading configuration,

[0125] FIG. 3 depicts a side view on the vibratory pile driving apparatus of FIG. 1,

[0126] FIG. 4 depicts a front view on the vibratory pile driving apparatus of FIG. 1,

[0127] FIG. 5a depicts a front view on the lifting yoke of the vibratory pile driving apparatus of FIG. 1,

[0128] FIG. 5b depicts a side view on the lifting yoke of FIG. 5a,

[0129] FIGS. 6a-6c depict various different embodiments of a dampening cassette for use in the vibratory pile driving apparatus of FIG. 1,

[0130] FIG. 7 depicts the embodiment of the vibratory pile driving apparatus, including other components, such as vibrator devices,

[0131] FIGS. 8a and 8b schematically depict a further embodiment of the vibratory pile driving apparatus according to the present invention from the side, and

[0132] FIGS. 9a and 9b depict a close-up view on the lifting corrector arm of the vibratory pile driving apparatus of FIGS. 8a and 8b.

[0133] Throughout the figures, the same reference numerals are used to refer to corresponding components or to components that have a corresponding function.

DETAILED DESCRIPTION OF EMBODIMENTS

[0134] FIG. 1 schematically depicts an embodiment of the vibratory pile driving apparatus according to the present invention, to which is referred with reference numeral 1. The vibratory pile driving apparatus 1 comprises a frame element 10, onto which other components, in particular a clamping device and vibrator device 30, are attached. The vibratory pile driving apparatus 1 further comprises a lifting yoke 20. For the sake of improving clarity of the drawings, the other components, such as vibrator devices are not visible in attached in FIGS. 1-4, but are displayed in FIG. 7.

[0135] The frame element 10 has a first side 11 and a second side 12, which are located opposite to each other. The lifting yoke 20 of the vibratory pile driving apparatus 1 is rotatably connected to the frame element 10 and is configured to support the weight of the vibratory pile driving apparatus 1 when the vibratory pile driving apparatus 1 is suspended from a crane. The lifting yoke 20 thereto comprises four lifting trunnions 21, which are, during use, configured to receive lifting cables that are attached to the crane.

[0136] The lifting yoke 20 and the frame element 10 are rotatable relative to each other during use of the pile driving apparatus 1 for upending the pile. This mutual rotation between the lifting yoke 20 and the frame element 10 is effected about a horizontal axis of rotation R, so that the pile driving apparatus 1 can be moved between a loading configuration and a pile driving configuration.

[0137] During this rotation, the lifting yoke 20 remains substantially stationary, for example aligned in a vertical direction V, as a result of being suspended from the crane. Meanwhile, the frame element 10 is rotated relative to the lifting yoke 20.

[0138] In FIG. 1, the vibratory pile driving apparatus 1 is shown in the pile driving configuration. The frame element 10 is thereby aligned substantially horizontally, so that the first side 10 is formed by a bottom surface of the frame element 10. The second side 12 is accordingly formed by a top surface of the frame element 10.

[0139] In FIG. 2, the vibratory pile driving apparatus 1 is shown in the loading configuration. In the loading configuration, the frame element 10 is aligned in a plane parallel to the vertical direction V, so that the first side 11 of the frame element 10 faces to the left and that the second side 12 of the frame element 10 faces to the right.

[0140] The stationary orientation of the lifting yoke 20 during movement of the pile driving apparatus 1 between the loading orientation and the pile driving configuration implies that the mechanical loads transmitted by the lifting yoke 20, i.e. from the frame element 10 towards the crane, remain substantially constant.

[0141] The frame element 10 comprises four vibrator mounting rails 13 at its second side 12, which are each configured to receive at least one vibrator device 30. The vibrator devices 30 are configured to subject the pile to a vibratory load and thereto comprise a hydraulic motor that is configured to drive multiple eccentric weights in rotation to obtain an oscillatory vibrational load. In FIG. 7, the vibratory pile driving apparatus 1 is displayed with the vibrator devices 30 mounted thereon.

[0142] The vibrator devices 30 are configured to exert vibrational loads on the frame element 10, which are, in turn, transmitted on the pile via the clamping device. The vibrator mounting rails 13 are fixedly attached to the frame element 10, in order to improve the transmission of vibrations on the pile that is clamped by the clamping device at the second side 12 of the frame element 10.

[0143] The vibrator mounting rails 13 extend in a horizontal direction H perpendicular to the axis of rotation R. As such, the vibrator mounting rails 13 extend in the horizontal direction H in the pile driving configuration and extend in the vertical direction V in the loading configuration.

[0144] The number of vibrator devices 30 can be selected on the basis of the requirements for the magnitude of the vibrations to which the pile needs to be subjected. According to the present embodiment, the frame element 10 comprises two outer vibrator mounting rails 13 and two inner vibrator mounting rails 13.

[0145] The inner vibrator mounting rails 13 have a length that is relatively large compared to the length of the outer vibrator mounting rails 13. Accordingly, the vibratory pile driving apparatus 1 comprises a total of six vibrator devices 30, as is shown in FIG. 7. Each of the inner vibrator mounting rails 13 is configured to receive two vibrator devices 30 and the outer vibrator mounting rails 13 are each configured to receive a single vibrator device 30.

[0146] The vibrator devices 30 are mounted on the vibrator mounting rails 13 symmetrically with respect to the axis of rotation R, i.e. seen in the pile driving configuration. This contributes to an improved distribution of weight, so that the centre of gravity of the frame element 10 with the clamping device and all vibrator devices 30 horizontally coincides with the lifting yoke 20, seen along the horizontal direction H.

[0147] The frame element 10 comprises a plurality of clamp mounting rails 14 at its first side 11 i.e. at the bottom side of the frame element 10 in the pile driving configuration. The clamp mounting rails 14 extend in a radial direction relative to the vertical direction V, in the pile driving configuration, and to the horizontal direction H perpendicular to the axis of rotation R, in the loading configuration.

[0148] In the loading configuration shown in FIG. 2, the clamping device points to the side and is therefore connectable to a head end of a pile that is in a horizontal configuration. This connection can be established by clamping of the pile with the clamping device at a number of points around the perimeter of the pile. In the pile driving configuration shown in FIG. 1, after upending, the pile eventually becomes aligned parallel to the vertical direction V and the first side 11 of the frame element 10 with the clamping device will end up facing down.

[0149] The vibratory pile driving apparatus 1 further comprises a clamping device, which is provided at the first side 11 of the frame element 10 and which comprises a plurality of hydraulic clamps, not shown in the figures. The clamps are configured to grip an upper edge of the pile and are configured to be attached to the clamp mounting rails 14 to define a circular pile clamping pattern between them. As such, the vibratory pile driving apparatus 1 is suited to insert or extract monopiles having a circular cross-section. The clamps are slidable along the clamp mounting rails 14 to adjust a diameter of the pile clamping pattern, so that the present vibratory pile driving apparatus 1 can be adjusted for various different types of piles, having different diameters. The diameter of the pile clamping pattern can be increased by moving the clamps in a radially outward direction, to be able to clamp a pile with a relatively large diameter. Similarly, the diameter of the pile clamping pattern can be reduced by moving the clamps in a radially inward direction, to be able to clamp a pile with a relatively small diameter.

[0150] During upending, mechanical forces between the crane and the pile can be regarded to bypass the vibrator devices 30. Hence, these loads are transmitted via the clamping device, the frame element 10 and the lifting yoke 20. The upending loads are not transmitted via the vibrator devices 30, which means that the present pile driving apparatus 1 does not suffer from the undesirable loading of resilient dampening elements in the vibrator devices 30.

[0151] The lifting yoke 20 is attached to the frame element 10 directly, by means of a hinge device 15 of the frame element 10. The lifting yoke 20 is thus not directly coupled to the vibrator devices 30, but rather indirectly, via the frame element 10. The lifting yoke 20 is in particular attached to a dynamic part of the pile driving apparatus 1, i.e. a part of the pile driving apparatus that is subjected to vibrational loads during use of the apparatus 1 for driving or extracting piles.

[0152] The frame element 10 comprises three hinge devices 15. The lifting yoke 20 is attached to the frame element 10 by means of the hinge devices 15. A single hinge device 15 is provided for each respective set of arms of the lifting yoke 20. The hinge devices 15 are configured to effect the mutual rotation between the lifting yoke 20 and the frame element 10 and thereto each comprise a hinge pin 16 extending through holes in the yoke arms of the lifting yoke 20.

[0153] The vibratory pile driving apparatus 1 further comprises a hydraulic actuator 40, which is attached to the frame element 10, at an actuator fixture 17 of the hinge device 15, and to an actuator fixture 24 of the lifting yoke 20. The actuator 40 is configured to move the frame element 10 relative to the lifting yoke 20 between the loading configuration and the pile driving configuration. The hydraulic actuator 40 is a hydraulic cylinder 40 and is configured to effect a mutual displacement between the actuator fixture 17 of the hinge device 15 and the actuator fixture 24 of the lifting yoke 20.

[0154] The axis of rotation R coincides with the combined centre of gravity of the frame element 10 and the vibrator devices 30, in order to reduce the effort needed to rotate the frame element 10 and the vibrator devices 30 relative to the lifting yoke 20.

[0155] The lifting yoke 20 further comprises a cable guiding device 22, which is configured to guide cables and hydraulic fluid lines departing from the pile driving apparatus 1. The cable guiding device 22 is attached to the lifting yoke 20 and is thus configured to remain substantially stationary as well, irrespective of a mutual position between the lifting yoke 20 and the frame element 10.

[0156] The cable guiding device 22 extends substantially horizontally away from the lifting yoke, in the horizontal direction H substantially perpendicular to the axis of rotation R. In the loading configuration of the vibratory pile driving apparatus 1 shown in FIG. 2, the cable guiding device 22 faces the second side 12 of the frame element 10, which implies that the cables and hydraulic fluid lines are guided away from the vibratory pile driving apparatus 1 in a direction away from the pile that is clamped.

[0157] The lifting yoke 20 in the present vibratory pile driving apparatus 1 is subdivided in a dynamic part, which is attached to the frame element 10, and a static part, with which the pile driving apparatus 1 is configured to be suspended from the crane. The lifting yoke 20 comprises a spreader bar 23, which forms part of the static part. The spreader bar 23 extends in a horizontal direction parallel to an axis of rotation R. The spreader bar 23 comprises the lifting trunnions 21, so that the vibratory pile driving apparatus 1 is configured to be suspended from the crane with the spreader bar 23. The spreader bar 23 horizontally spans above the frame element 10, having a width along the axis of rotation R substantially corresponding to a width of the frame element 10, as is best shown in FIG. 4.

[0158] As a result of the lifting yoke 20 comprising both a static part and a dynamic part, it is still desired to inhibit transmission of vibrations from the dynamic part towards the crane. To this effect, the lifting yoke 20 comprises a plurality of resilient dampening elements 50. These dampening elements 50 are functionally arranged in between the dynamic part and the static part, to inhibit transmission of vibrations from the dynamic part to the static part and thus to inhibit transmission of vibrations to the crane.

[0159] The lifting yoke 20 is thereto configured to dampen relative movements between the dynamic part of the lifting yoke 20 and the static part thereof with the dampening elements 50. The dampening elements 50 are thereby configured to deform in a direction substantially parallel to the vertical direction V during use, since the lifting yoke 20 remains in a substantially vertical orientation both in the loading configuration and the pile driving configuration, and in all relative positions of the lifting yoke 20 between these configurations. The dampening elements 50 are positioned to be able to accommodate deformations in the vertical direction V, to be able to dampen vibrations from the vibrator devices 30 in the vertical direction V. As a result, the dampening elements 50 may not be subjected to deformations other than in the vertical direction V, thereby avoiding undesired damaging of the dampening elements 50.

[0160] In the present embodiment of the vibratory pile driving apparatus 1, the dampening elements 50 are made of a synthetic rubber material, which is an elastomeric material having resilient properties, thereby being able to deform elastically when loaded. As a result, the deformations of the elastomeric material may be used to compensate for mutual displacements within the lifting yoke 20, i.e. between the dynamic part and the static part, thereby allowing for inhibition of vibrations by the lifting yoke 20. The synthetic rubber material is thereby able to offer desired dampening properties, whilst still offering a strength sufficient for use in a vibratory pile driving apparatus 1.

[0161] According to the present embodiment, the lifting yoke 20 comprises a number of downward yoke arms 25, which are attached to the spreader bar 23 and which form part of the static part of the lifting yoke 20. The downward yoke arms 25 extend away from the spreader bar 23 in a downward vertical direction. The lifting yoke 20 further comprises a number of upward yoke arms 26, which are rotatably attached to the hinge devices 15 and which form part of the dynamic part of the lifting yoke 20.

[0162] The upward yoke arms 26 extend away from the frame element 10 and from the hinge devices 15 in an upward vertical direction The downward yoke arms 25 and the upward yoke arms 26 thus extend in opposite directions, respectively having free lower ends and free upper ends. The dampening elements 50 are attached in between the downward yoke arms 25 and the upward yoke arms 26 and are thereby configured to form a resilient connection between the downward yoke arm 25 and the upward yoke arm 26 to inhibit transmission of vibrations between them.

[0163] The dampening elements 50 in between the downward yoke arms 25 and the upward yoke arms 26 are subjected to shear forces, following mutual vertical displacements between the downward yoke arms 25 and the upward yoke arms 26, since they are loaded in a substantially vertical direction V. Accordingly, the dampening elements 50 are configured to accommodate mutual shear strains between the downward yoke arms 25 and the upward yoke arms 26.

[0164] Each one of the downward yoke arms 25 at least partially faces one or more of the upward yoke arms 26, i.e. overlapping with each other partly in a vertical plane. Part of the downward yoke arm 25 thus lies directly opposite to part of the upward yoke arm 26, seen in a vertical plane. The dampening elements 50 are attached in between these overlapping parts of the yoke arms 25, 26. The downward yoke arms 25 and upward yoke arms 26 that face each other with dampening elements 50 in between them are defined herein as sets of yoke arms 25, 26.

[0165] In the present embodiment, the lifting yoke 20 comprises two opposed sideward sets 27 of yoke arms 25, 26, as is best shown in FIG. 5a. The sideward sets 27 of yoke arms 25, 26 are provided at opposite ends of the spreader bar 23 and are formed by downward yoke arms 25 that downwardly extend from the spreader bar 23 and by the upward yoke arms 26 that are arranged at opposite sides of the frame element 10.

[0166] Each sideward set 27 of yoke arms 25, 26 comprises two downward yoke arms 25 and a single upward yoke arm 26, which are aligned parallel to each other and which are spaced at a distance from each other. A spacing is present between the downward yoke arms 25, in which the upward yoke arm 26 is provided, centrally in between the downward yoke arms 25.

[0167] For each of the sideward sets 27 of yoke arms 25, 26, the lifting yoke 20 comprises a respective dampening element 50 in between the central upward yoke arm 26 and each of the outer downward yoke arms 25. This configuration offers symmetric loading of the sideward sets 27 of yoke arms 25, 26 and provides that the dampening elements 50 at the opposite sides of the central upward yoke arm 26 are loaded in parallel.

[0168] The lifting yoke 20 further comprises a central set 28 of yoke arms 25, 26, which is located centrally in between the opposed sideward sets 27 of yoke arms 25, 26. The central set 28 of yoke arms 25, 26 comprises three downward yoke arms 25 that are spaced at a distance from each other along the axis of rotation R, defining two spacings in between them. Accordingly, the central set 28 of yoke arms 25, 26 comprises two upward yoke arms 26, each projecting in a respective spacing between the downward yoke arms 25. The central set 28 of yoke arms 25, 26 comprises four dampening elements 50, which are provided side by side between the yoke arms 25, 26 of the central set 28. These four dampening elements 50 are loaded in parallel to each other and in parallel to the dampening elements 50 in the sideward sets 27 of yoke arms 25, 26, to further increase the loads that can be transmitted between the downward yoke arms 25 and the upward yoke arms 26.

[0169] With the central set 28 of yoke arms 25, 26 being present, the space between the sideward sets 27 of yoke arms 25, 26 is subdivided in two space parts 18. The vibrator mounting rails 13 project in these space parts 18, so that the vibrator devices 30 are arranged on opposite sides of the central set 28 of yoke arms 25, 26. The placement of vibrator devices 30 on these vibrator mounting rails 13 allows that rotation of the frame element 10 relative to the lifting yoke 20 is not obstructed by the vibrator devices 30 colliding with the lifting yoke 20. Furthermore, each of these space parts 18 comprises an equal number of vibrator devices 30, as is best shown in FIG. 7, to obtain a substantially symmetrical vibratory pile driving apparatus 1.

[0170] It is furthermore shown best in FIG. 5b that all downward yoke arms 25 vertically project beyond their respective hinge devices 15 and that the downward yoke arms 25 each comprise a slotted hole 29 that is substantially elongate in the vertical direction V. The hinge pins 16 project through the slotted holes 29 in the downward yoke arms 25, but do not contact the downward yoke arms 25 during normal use of the vibratory pile driving apparatus 1, i.e. during upending and during vibrating.

[0171] The slotted holes 29 are configured to only contact the downward yoke arms 25 in case of failure of one or more of the dampening elements 50. Hence, this could cause the normal connection between the upward yoke arms 26 and downward yoke arms 25 via the dampening elements 50 to break, resulting in a drop of the frame element 10 relative to the lifting yoke 20. The hinge pin 16 may then become supported in the slotted hole 29 of the downward yoke arm 25, which thus offers an emergency support.

[0172] In the vibratory pile driving apparatus 1 shown in the figures, the dampening elements 50 are modular dampening cassettes 50. Several examples of these dampening cassettes 50 are displayed in FIGS. 6a-6c. Each of these dampening cassettes 50 comprises a changeable number of dampers 52, which are deformable in parallel to each other. The dampening cassettes 50 comprise a number of dampers 52 that corresponds to a height or width of the overlap between the upward yoke arm 26 and the downward yoke arm 25 with which they are associated.

[0173] In the vibratory pile driving apparatus 1 according to the present invention, a single dampening cassette 50 is provided between each opposed downward yoke arm 25 and upward yoke arm 26. The sideward set 27 of yoke arms 25, 26 comprises a single upward yoke arm 26 in between two downward yoke arms 26 and therefore comprises two dampening cassettes 50, i.e. one at each side of the upward yoke arm 26. The central set 28 of yoke arms 25, 26, on the other hand, comprises two upward yoke arms 26 in between three downward yoke arms 25 and therefore comprises four dampening cassettes 50, i.e. one at each side of both upward yoke arms 26.

[0174] The dampening cassette 50 in FIG. 6a comprises five dampers 52, which are mounted in between two opposed cassette frames 51 having five corresponding mounting positions. The dampening cassettes 50, 50 in FIGS. 6b and 6c respectively comprise three dampers 52s and two dampers 52, which are mounted in between two opposed cassette frames 51, 51 having three and two corresponding mounting positions.

[0175] The dampening cassette 50 in FIG. 6a has a relatively large number of dampers 52 and is thus preferably applicable for lifting yokes of which the yoke arms overlap over a relatively large distance. However, when the yoke arms only overlap over a small distance, the relatively small dampening cassettes from FIGS. 6b and 6c may be applied, comprising a relatively small number of dampers.

[0176] FIGS. 8a and 8b schematically depict a further embodiment of the vibratory pile driving apparatus according to the present invention from the side, to which is referred with reference numeral 101. This vibratory pile driving apparatus 101 comprises all components of the vibratory pile driving apparatus 1 shown in FIGS. 1-6, and additionally comprises a lifting corrector arm 102.

[0177] This embodiment of the vibratory pile driving apparatus 101 further comprises an even number primary lifting lines 103, of which two are visible in the side view in FIGS. 8a and 8b. The primary lifting lines 103 are embodied as lifting cables and are attached to the lifting yoke 120. The primary lifting lines 103 are configured to be attached to a crane for suspending the vibratory pile driving apparatus 101.

[0178] The lifting corrector arm 102 is attached to the lifting yoke 120 and is rotatable relative to the lifting yoke 120 between an inner position, shown in FIG. 8a and in FIG. 9a, and an outer position, shown in FIG. 8b and in FIG. 9b. The vibratory pile driving apparatus 101 comprises two hydraulic actuators 105 for moving the lifting corrector arm 102 relative to the lifting yoke 120.

[0179] The vibratory pile driving apparatus 101 further comprises an auxiliary lifting line 104, which is attached to the lifting corrector arm 102 and which is configured to be attached to the crane as well. The lifting corrector arm 102 and the auxiliary lifting line 104 are together configured to shift a suspension point S the vibratory pile driving apparatus 101 relative to a vertical axis G through the centre of gravity of the vibratory pile driving apparatus 101.

[0180] In the inner position of the lifting corrector arm 102, shown in FIG. 8a, the entire weight of the vibratory pile driving apparatus 101 is suspended by the primary lifting lines 103. In this inner position, the suspension point S of the vibratory pile driving apparatus 101, i.e. the point where the lifting lines 103, 105 are attached to the crane, are aligned vertically above the centre of gravity of the vibratory pile driving apparatus 101.

[0181] In the outer position of the lifting corrector arm 102, shown in FIG. 8b, the auxiliary lifting line 105 is tensioned and part of the weight of the vibratory pile driving apparatus 101 becomes suspended by the auxiliary lifting line 105. In this configuration, at least one of the primary lifting lines 103 becomes relaxed.

[0182] Due to the outward movement of the lifting corrector arm 102 towards the outer position, the suspension point S of the vibratory pile driving apparatus 101 is shifted relative to the centre of gravity of the vibratory pile driving apparatus 101. The suspension point S thereby becomes aligned with a vertical axis G offset relative to the centre of gravity of the vibratory pile driving apparatus 101. As such, the stability of the vibratory pile driving apparatus 101 is adjusted.