Vibration device

Abstract

 A vibrator device (5) for sinking an elongate ground element (7) into a ground comprises a clamping device with at least one clamping member (61,62) which bounds an infeed cavity (6) on a periphery and is able and adapted to engage clampingly on an outer wall of the ground element during operation. At least one vibrator block (51,52) is connected to the clamping device and able and adapted to apply an axial vibration during operation to a ground element clamped by the clamping device. The vibrator block (51,52) is herein provided laterally of the clamping device (61,62) and connected rigidly to the at least one clamping member. The at least one vibrator block (51,52) and the at least one clamping member (61,62) are together adjustable between a clamping position and a release position during operation in order to clamp the ground element fixedly in the infeed cavity in the clamping position and to release it therefrom in the release position.

Description

[0001] The present invention relates to a vibrator device for sinking an elongate ground element into a ground, comprising a clamping device with at least one clamping member which bounds an infeed cavity on a periphery and is able and adapted to engage clampingly on an outer wall of the ground element during operation, and comprising at least one vibrator block connected to the clamping device and able and adapted to apply an axial vibration during operation to a ground element clamped by the clamping device, wherein the at least one vibrator block is provided laterally of the clamping device, on a side thereof remote from the infeed cavity.

[0002] Such a vibrator device is for instance known from Netherlands patent number 1028140 and is applied particularly for the purpose of driving foundation piles and tubes into the ground. The known vibrator device comprises a clamping device which is equipped with a clamping chain which fits around a large part of a periphery of the infeed cavity. The clamping chain can be adjusted inside the clamping device by means of an adjusting cylinder between a tensioned position, wherein the clamping chain engages clampingly on the outer wall of the tube, and a release position wherein the tube is released in the infeed cavity. The clamping device is here received within a pair of vibrator blocks which apply a linear vibration to the clamped tube during operation. The fixed frame of the clamping device here transmits the vibrations from the vibrator blocks to the clamping chain with the tube.

[0003] A drawback of the known vibrator device is a relatively high weight of its own, this particularly making itself felt when the device is carried a great height onto a mast, as is usual for the purpose of driving relatively long foundation elements into the ground.

[0004] The present invention has for its object, among others, to provide a particularly efficient vibrator device with a relatively low weight of its own.

[0005] In order to achieve the stated object a vibrator device of the type described in the preamble has the feature according to the invention that the at least one vibrator block is rigidly connected directly to the at least one clamping member, and that the at least one vibrator block and the at least one clamping member are together adjustable between a clamping position and a release position during operation in order to clamp the ground element fixedly in the infeed cavity in the clamping position and to release it therefrom in the release position. The vibrator block is thus connected directly to the at least one clamping member so that there is no need for an intermediate adjustable construction in the clamping device. The vibrations are instead transmitted by the vibrator block directly to the clamping member connected thereto, whereby a significant weight reduction is achieved, which can amount in practice to several tons, and vibration losses are limited to a minimum.

[0006] A particular embodiment of the vibrator device according to the invention is characterized in that the at least one clamping member comprises a first clamping shoe and a second clamping shoe, that a first vibrator block is rigidly connected directly to the first clamping shoe, that a second vibrator block is rigidly connected directly to the second clamping shoe and that the vibrator blocks are adjustable together with the respective clamping shoes. The clamping means thus comprise a pair of clamping shoes which are able and adapted to engage clampingly on the outer wall of the tube. In the clamping position the clamping shoes move toward each other in order to clamp the ground element, while the clamping shoes are moved away from each other in the release position and thus release the ground element from the infeed cavity. For this purpose the clamping shoes can be urged apart in a linear movement, although a preferred embodiment of the vibrator device according to the invention has the feature that the vibrator blocks are pivotable with the clamping shoes round a shared pivot axis of the clamping device. The two clamping shoes thus pivot together with the vibrator blocks connected thereto round a fixed pivot point to engage round the ground element when pivoted toward each other, and to move apart in opposite direction so as to thus release the ground element.

[0007] In a further particular embodiment the vibrator device according to the invention has the feature that the clamping shoes are mutually connected on a side of the infeed cavity remote from the pivot axis via a linear actuator, and particularly via a pressure cylinder with a hydraulically driven piston. Such an actuator can be extended mechanically in order to drive the clamping shoes apart during an outward stroke and to clamp the clamping shoes round the ground element during an inward stroke. The direct engagement on the clamping shoes limits losses in the transmission of the forces to the ground element required for this purpose.

[0008] Vibrator blocks of diverse nature can be applied per se in the vibrator device according to the invention. Particularly favourable results have been obtained with a further particular embodiment of the vibrator device according to the invention, which is characterized in that the two vibrator blocks each comprise a pair of at least substantially identical eccentric discs which are rotatable in opposite directions, wherein at least during vibration a mass centre of each eccentric disc lies eccentrically relative to a rotation shaft thereof. During rotation the eccentric mass centre of the discs causes an intrinsic vibration, a horizontal component of which is compensated by an opposite, similar component of the other of the pair of discs. The device is thus at least substantially vibration-free in horizontal direction and vibrates at least substantially only in vertical direction. In order to ensure that the two discs remain completely in phase, a further particular embodiment has the feature here that the eccentric discs of each pair of eccentric discs are mutually coupled by a gear transmission.

[0009] For a stable operation of the device it is also advantageous for the vibrator blocks to also run mutually in phase, or synchronously. For this purpose a further preferred embodiment of the vibrator device according to the invention has the feature that the two vibrator blocks each comprise a mechanical drive, particularly a hydromotor, and that the pairs of eccentric discs thereof are mutually coupled by a synchronizing shaft. Although the vibrator blocks here each have their own direct drive, the same stroke will thus be imposed thereon by the synchronizing shaft. The vibrator blocks thereby always vibrate in phase with each other, thereby achieving an optimal drive force on the ground element.

[0010] A further particular embodiment of the vibrator device according to the invention has the feature here that the synchronizing shaft comprises an articulated shaft which allows at least an axial adjustment. The synchronizing shaft is thus able to adjust at least axially to a current position of the vibrator blocks in order to allow an unimpeded adjustment thereof together with the clamping members. A preferred embodiment of the vibrator device according to the invention is characterized here in that the synchronizing shaft is arranged on a side of the infeed cavity directed toward the pivot axis of the clamping device. By thus positioning the synchronizing shaft close to the pivot axis, it is possible to suffice with a relatively small adjustability thereof in order to provide the vibrator blocks with sufficient freedom of movement, whereby the construction of the synchronizing shaft can remain relatively simple.

[0011] The invention will be further elucidated hereinbelow on the basis of an exemplary embodiment and an accompanying drawing. In the drawing:

figure 1

shows a view of a foundation device in which an exemplary embodiment of a vibrator device according to the invention is applied;

figure 2

shows a section of the vibrator device applied in the foundation device of figure 1;

figure 3

shows a rear view of the vibrating means of the vibrator device of figure 2;

figure 4

shows a front view of the vibrating means of the vibrator device of figure 2;

figure 5

shows a section of the vibrating means of figures 3 and 4 in a release position; and

figure 6

shows a section of the vibrating means of figures 3 and 4 in a clamping position.

[0012] The figures are purely schematic and not drawn to scale. Some dimensions in particular can be exaggerated to a greater or lesser extent for the sake of clarity. Corresponding parts are generally designated with the same reference numeral.

[0013] The foundation device shown in figure 1 comprises a moving vehicle 1 with a cab 2, from which extends a guide column 3 which can be erected to the operating position shown in the figure by means of a hydraulic cylinder 4. A vibrator device 5 according to the invention is connected for axial movement to guide column 3. Provided here in or on the guide column are drive means (not further shown) with which the vibrator device can be driven downward with a thrust in the order of 70 to 240 kN. The vibrator device comprises an internal infeed cavity 6 in which an elongate ground element 7 is received in fixedly clamped manner and which can thus be driven with said thrust into an underlying ground 8. Ground element 7 for instance comprises a foundation pile or foundation tube, but can otherwise be of diverse nature. By means of a lifting device 9 provided for this purpose at the top of column 3 the tube can be placed from above inside the infeed cavity of vibrator device 5.

[0014] In order to facilitate penetration of the ground, and particularly to be able to pass through heavier ground layers, vibrator device 5 comprises vibrating means with which an oscillating vibration in the order of 1500-3000 vibrations per minute can be applied to the ground element. Vibrator device 5 is shown in more detail in figure 2, and comprises for this purpose two vibrator blocks 51,52, or vibrator assemblies. The vibrator assemblies are freely suspended in a surrounding frame 50, usually referred to as pull cover, which extends for axial movement from guide column 3 and can be moved both upward and downward from the foundation device with the above stated thrust. A tube body 7 clamped in infeed cavity 6 can thus be driven into or pulled out of ground 8 in a linear movement. In order to accelerate the introduction into the ground here, and also be able to pass through denser and thereby heavier ground layers, the tube body can also be forced into a linear vibration using vibrator device 5. For this purpose the two vibrator assemblies 51,52 have available a pair of eccentric discs 53 which are each driven by a hydromotor 55. Eccentric discs 53 comprise a gear ring 54 at their base and are thereby in mutual engagement for the purpose of performing a rotation in opposite directions. The two eccentric discs 53 take an identical form with a mass centre eccentrically of their own rotation axis, whereby the two discs will perform a rotation in opposite directions and will set the whole into an at least substantially purely vertically directed vibration. A rotation speed of hydromotors 55, and thereby of eccentric discs 53, can be regulated here in a range of 1500 to 3000 revolutions per minute.

[0015] Situated between the two vibrator blocks is a clamping device with a pair of clamping shoes 61,62 which on the one hand are rigidly connected to a respective vibrator block 51,52 and on the other bound the infeed cavity and during operation herein engage clampingly on an outer wall of a ground element 7 inserted into infeed cavity 6. Clamping shoes 61,62 are mounted directly and at least substantially without clearance on vibrator assemblies 51,52 using bolts or by means of welding, and will thereby be set into vibration generated thereby and transmit this vibration one to one to the ground element clamped therein. Owing to the absence of intermediate moving parts between clamping shoes 61,62 and vibrator assemblies 51,52 the whole construction can remain relatively light, and the vibrations generated by vibrator blocks 51,52 are transmitted practically without losses to ground element 7.

[0016] In order to enable clamping and eventual release of ground element 7, clamping shoes 61,62 are adjustable in frame 50 together with vibrator blocks 51,52. For this purpose, see figure 3, the one vibrator block 51 is connected on a rear side, together with the one clamping shoe 61, to the other clamping shoe 62 and the other vibrator block 52 for pivoting round a pivot shaft 65. On a front side a pair of hydraulically extensible cylinders 66,67 extends between the two halves of the vibrator device, see figure 4, to drive the two halves apart round the pivot shaft to the release position shown in figure 5 or move them toward each other to the active position shown in figure 6. In this latter position the two clamping shoes 61,62 engage clampingly on the outer wall of the ground element, whereby it is fixed firmly inside the vibrator device.

[0017] In order to ensure that the two vibrator assemblies 51,52 run synchronously to each other and the whole remains as stable as possible in the horizontal plane, the two vibrator assemblies 51,52 between infeed cavity 6 and pivot shaft 65 are mutually coupled by means of a synchronizing shaft 58. This shaft 58 does not take a rigid form here but is articulated in order to provide an axial and radial freedom of movement which allows an unlimited relative adjustability of the two halves 51,61..52,62 of the vibrator device. The synchronizing shaft forces both vibrator assemblies into the same stroke, while the two gear rings 54 on the eccentric discs provide for a mutual synchronization within a vibrator assembly. The horizontal components of the oscillations transmitted by the eccentric discs thus at least substantially wholly compensate each other and an optimum efficiency is achieved in vertical direction. Despite a relatively low weight of its own in the order of 6000 kg, the vibrator device shown in this example is hereby nevertheless able to produce a thrust in the order of 70-240 kN with vibrations in the order of 1500-3000 per minute. Existing devices which are able to achieve such performance require a construction of one and a half times to twice this weight. This results in a considerably greater stability of the foundation device during operation, wherein the vibrator device is situated at (great) height on the guide column, and thereby also requires a lighter vehicle.

[0018] Although the invention has been elucidated above with reference to only a single embodiment, it will be apparent that the invention is by no means limited thereto. On the contrary, many other variations and embodiments are still possible within the scope of the invention for a person with ordinary skill in the art. Instead of using clamping shoes, it is thus possible to opt for a clamping chain which clamps round the outer wall of a ground element. As well as being suitable for round, tubular ground elements the device is also suitable for ground elements of other cross-section, wherein a cross-section of the infeed cavity and a boundary surface of the clamping members or the clamping member will be modified accordingly. Instead of fixed eccentric discs adjustable eccentric discs can also be applied, the mass centre of which can be mechanically extended radially relative to the rotation shaft during operation.

Claims

1. Vibrator device for sinking an elongate ground element into a ground, comprising a clamping device with at least one clamping member which bounds an infeed cavity on a periphery and is able and adapted to engage clampingly on an outer wall of the ground element during operation, and comprising at least one vibrator block connected to the clamping device and able and adapted to apply an axial vibration during operation to a ground element clamped by the clamping device, wherein the at least one vibrator block is provided laterally of the clamping device, on a side thereof remote from the infeed cavity, characterized in that the at least one vibrator block is rigidly connected directly to the at least one clamping member, and that the at least one vibrator block and the at least one clamping member are together adjustable between a clamping position and a release position during operation in order to clamp the ground element fixedly in the infeed cavity in the clamping position and to release it therefrom in the release position.

2. Vibrator device as claimed in claim 1, characterized in that the at least one clamping member comprises a first clamping shoe and a second clamping shoe, that a first vibrator block is rigidly connected directly to the first clamping shoe, that a second vibrator block is rigidly connected directly to the second clamping shoe and that the vibrator blocks are adjustable together with the respective clamping shoes.

3. Vibrator device as claimed in claim 2, characterized in that the vibrator blocks are pivotable with the clamping shoes round a shared pivot axis of the clamping device.

4. Vibrator device as claimed in claim 3, characterized in that the clamping shoes are mutually connected on a side of the infeed cavity remote from the pivot axis via a linear actuator, and particularly via a pressure cylinder with a hydraulically driven piston.

5. Vibrator device as claimed in claim 3 or 4, characterized in that the two vibrator blocks each comprise a pair of at least substantially identical eccentric discs which are rotatable in opposite directions, wherein a mass centre of each eccentric disc lies eccentrically relative to a rotation shaft thereof.

6. Vibrator device as claimed in claim 5, characterized in that the eccentric discs of each pair of eccentric discs are mutually coupled by a gear transmission.

7. Vibrator device as claimed in claim 5 or 6, characterized in that the two vibrator blocks each comprise a mechanical drive, particularly a hydromotor, and that the pairs of eccentric discs thereof are mutually coupled by a synchronizing shaft.

8. Vibrator device as claimed in claim 7, characterized in that the synchronizing shaft comprises an articulated shaft which allows at least an axial adjustment.

9. Vibrator device as claimed in claim 7 or 8, characterized in that the synchronizing shaft is arranged on a side of the infeed cavity directed toward the pivot axis of the clamping device.

Drawing