DK178765B1 - A clamping device, one selvfremrykkende climbing device and a method for coupling the same to a tubular structure - Google Patents

Abstract

There is disclosed a clamping device, a self-advancing climbing device including two such clamping devices, and a method of coupling such a clamping device to a tubular shape. In one embodiment of the invention there is disclosed a clamping device (1) for a tubular form, in particular a thin-walled tubular form, such as the tower (3) for a wind turbine. The clamping device (1) comprises at least one clamping element in the form of a friction pad (9) adapted to grip the tear net (3), and at least one elastic elongated actuating element in the form of a clamping means (1 6) which is arranged to exert a force on the friction pad (9) to push the pad (9) to grip the tower (3), whereby the pad (9) and the clamping element (16) are arranged to exert a substantially equal, radial clamping load on the tower (3).

Description

Title beer: A clamping device, a self-advancing climbing device and a method of connecting the same to a tubular structure

The present invention relates to a clamping device, a self-advancing climbing device comprising two such clamping devices, and a method of coupling a clamping device to a tubular shape. In particular, the present invention relates to, but not exclusively, a clamping device for a thin-walled tubular form, such as a wind turbine tower, and a method for coupling a clamping device to such a thin-walled tubular shape.

As is well known, pipelines are tubular structures used in various industries for the transportation of fluids. In the oil and gas extraction and production industries, pipelines are often laid on the seabed for the transport of hydrocarbon-containing hydrocarbons, from offshore locations to onshore locations. In a pipe laying process, it is necessary to support and hold the pipeline during laying from a pipe laying vessel on the seabed. This is achieved by using clamping devices which have friction pads which are prevented in axial motion relative to the pipeline and which are coupled to the pipeline using a direct pressure over the area of the pad.

Clamping devices of this type are intended to apply a stress load over as large a portion of the perimeter of the pipeline as possible to avoid ovalisation or collapse due to instability. U.S. Patent Publication No. 2002/0009333 (Willis and Turnbull) discloses such a clamping device, the clamping device including a plurality of radially oriented pistons, each piston carrying a correspondingly rigid shoe having a curved radiused surface, which shoe is pressed to abut against the pipeline, and a friction tile mounted on the shoe's surface to increase grip on the pipeline. The piston shoes essentially surround the pipeline as they move.

While clamping devices of this type are effective for holding pipelines of known and fixed external diameters, a clamping device having different shoe dimensions is required for pipelines of different diameters. Clamp devices of this type are therefore unsuitable for use with tubes of varying diameters.

Furthermore, the clamping shoes, while effective in avoiding ovalisation or collapse of such a pipeline, are far from imposing a substantially equal radial load around the circumference of the tube. This is because the radially oriented pistons exert a greatest radial load on the tube in a direction parallel to the axis of the piston. At points on the shoe at a distance from the piston axis (and at a circumferential distance around the pipeline), the piston exerts a smaller load. This ultimately leads to variations in the local load on the pipeline around the perimeter of the pipeline. Pipelines laid using such a clamping device typically have diameters in the range of from 0.150 m to 0.6 m and diameter to thickness ratios of between 10 and 20, and are therefore relatively strong. However, the diameters of the wind turbine towers are often substantially larger than this, and the towers are tapered towards the top. In particular, the majority of current turbine towers have a diameter of about 4 m to 5 m at the bottom and about 2.5 m to 3 m at the peak and diameter-to-thickness ratios of between 165 and 295. The current turbine towers also have a circumference of 15.7 m at the bottom and 8 m at the top, a difference of 7.7 m. Future towers are likely to have diameters of about 11 m at the bottom and tapering to 3 m at the top. The perimeter of such towers will therefore vary between about 34.5 m and 9.5 m, a difference of 25 m.

Wind turbine towers are therefore relatively thin-walled relative to pipelines and are unable to maintain their circular shape when subjected to variations in loads around their perimeter, thus having a built-in tendency for local folding and collapse. In particular, this creates problems during the transportation of wind turbine towers, as the tower sections tend to bend and become oval, as discussed in U.S. Patent No. 6,592,331 (Wobben). Because of this and because the towers are tapered from the bottom up, it would not be possible to use a clamping device of the type described in US2002 / 0009333, with fixed radius shoes, on wind turbine towers.

German Patent Publication No. 19647515 (Otto) describes a mechanism for use in the construction of a wind turbine. The mechanism is used to install the wind turbine tower sections on top of one another to assemble the tower and subsequently to install a power unit head at the top of the tower. In general terms, the mechanism includes a rigid, rigid, arch-shaped foot coupled to the tower, which is hoisted up the tower using a crane coupled to the foot. However, the foot is coupled to the tower in a way that will lead to variations in the load on the tower around its perimeter (point loads), which, as discussed above, is unable to support such load. In fact, the invention, the mechanism, is far from exerting an equal radial load on the turbine tower, and local folding is likely to be in use. For example, in one embodiment of DE 19647515, the foot of the mechanism is coupled to the tower by a plurality of cables extending around the tower from the clamping device and which are clamped with hydraulic pistons mounted on the foot. When the pistons are activated, the loads exerted on the tower by the foot and cable are not an equal radial load, and variations in load will be a result, leading to loss of circular shape and local folding.

In addition, using the crane's own weight using the mechanism of DE 19647515, and in particular external loads carried by the mechanism (such as sections of the tower), will generate cantilever loads that are transmitted to the tower with the foot. These cantilever loads will induce local reactionary radial forces in the tower, which also leads to loss of circular shape and local folding.

Furthermore, the high weight of the mechanism, even if the tower is capable of carrying such cantilever forces, requires that such a clamping force be exerted on the tower that there is a likelihood of all-inclusive failure in the tower construction. SU 1791202 A1 describes an apparatus which can be clamped to a tubular structure. The apparatus comprises a bearing for placing the tubular structure and frictional surfaces intended to jointly extend in a semi-arcuate shape against the tubular structure located on the bearing. The apparatus further comprises means for moving the friction surfaces relative to the bearing and tubular structure and means for applying load to the friction surfaces. The means for moving the friction surfaces are load arms where these load arms can be moved in a first direction to bring the friction surfaces into contact with the tubular structure and in an opposite direction to bring the friction surfaces out of contact with the tubular structure.

It is among the objects of embodiments of the present invention to avoid or reduce at least one of the foregoing disadvantages. In a first example, a tubular clamping device is provided, the clamping device comprising: at least one friction pad adapted to grip the tubular shape and at least one elastic elongated clamping member adapted to exert a force on the friction pad for pressing the friction pad to grip the tubular mold, whereby the friction pad and clamping member are arranged to exert a substantially equal, radial clamping load on the tubular mold, which clamping load is independent of external loads applied to the clamping device.

Exercising a substantially equal, radial clamping load provides for the generation of a substantially equal annular load in the tubular form. This overcomes problems associated with previous clamping devices and other mechanisms by avoiding or at least minimizing variations in the load around the perimeter of the tubing, avoiding or decreasing the probability of local folding. It will be appreciated that references herein to the application of a substantially equal, radial clamping load to the tubular form are for exerting forces on a surface of the tubular shape around a circumference thereof, the forces being directed along the radii of the tubular shape and being substantially equal around the perimeter of the tubing. The radial clamping load is independent of external loads applied to the clamping device, there being or not substantially any increase / decrease in the clamping load created when an external load is carried by the clamping device. Furthermore, the structure of the clamping device is such that the clamping elements are insulated from any other force and in particular are insulated from external loads exerted on the clamping device.

It will also be understood that the reference herein to a tubular form is to a hollow member or structure which is typically a thin-walled elongated member such as a wind turbine tower. In one example, a clamping device is provided for a tubular form, the clamping device comprising: at least one friction pad adapted to grip the tubular shape and a plurality of elastic elongate clamping elements adapted to exert a force on the friction pad, of which there is at least one, to press the friction pad to grasp the tubular shape, the clamping device and the tensioning member being arranged to exert a substantially equal, radial clamping load on the tubular shape, which clamping load is independent of external loads applied the clamping device, wherein the friction pads are arranged to be spaced in a direction along a principal axis of the tubular shape, and wherein at least one of the clamping elements is adapted to be tensioned using a traction directed in a circumferential direction around the tubular shape opposite that of a tubular shape. other clamping element.

The elastic elongated tension members provide for the application of a substantially equal, radial load and thus an equally induced annular load in the tubular form. However, some variation in the tensile force of the tension members may occur along the length of the member due to friction between the tension member and the surface of the tubular form. In particular, the inventors have found that the clamping force in the clamping element may be greatest closest to the application point of the tensile load (the clamping element is typically tensioned with a winch or the like) and becomes smaller along the length of the clamping element away from the application point. By clamping at least one of the clamping elements by applying a traction directed in an opposite circumferential direction around the tubular shape to that of another clamping element, variations in the radial loads exerted on the tubular shape of the clamping device (and therefore in induced ring loading) ) due to variations in the tensile force of the tensioning elements are avoided or at least minimized.

The clamping members may have first and second ends where one of the ends is arranged to be coupled, secured or secured relative to a support structure for the clamping device and the other end is arranged to be coupled to a winch or the like to clamp the clamping member. At least one of the clamping elements can be clamped using a traction force at an opposite end to that of another clamping member. Thus, one of the first ends of the tensioning members can be tensioned to generate a pulling force in a first circumferential direction around the tubular shape, and the respective second end of a second tensioning element can be tensioned to generate a pulling force in a second circumferential direction around the tubular shape opposite the first direction. It will be understood that a number of clamping elements can be clamped in the first direction and a number of others in the second direction. For example, axially adjacent clamping elements can be tensioned in opposite directions. Alternatively, an axially adjacent pair (or more) of clamping members may be tensioned in an opposite direction to another, optionally adjacent, pair of clamping members. Alternatively, both ends of the clamping members may be arranged to clamp. In one example, a clamping device is provided for a tubular form, the clamping device comprising: at least one clamping device adapted to grip the tubular shape and a plurality of elastic elongate clamping elements adapted to exert a force on the friction pad, of which there is at least one, to press the friction pad to grasp the tubular shape, each clamping member being arranged to pass around a circumference of the tubular mold and to overlap in a distance along a major axis of the tubular mold, the friction pad and clamping member are arranged to exert a substantially equal, radial clamping load on the tubular shape, which clamping is independent of external loads applied to the clamping device, the overlap positioning of at least one of the clamping members being arranged to be spaced about a circumference. the tubular shape relative to the overlap position of another clamping member.

As noted above, variations in the tension of the tension members may occur along the length of the tension member. However, positioning the overlap locations around the perimeter of the tubing provides minimization of variations in the resulting radial load on the tubular and thus minimizing variations in the induced annular loading. It will be appreciated that the overlap locations of the clamping elements are spaced apart around the circumference of the tubular form by appropriate placement of the clamping elements around the clamping device. The overlay locations of the clamping members may be arranged to be spaced equally spaced around the perimeter of the tubular form. For example, the overlap locations may be spaced 180 degrees around the perimeter of the tubular form, where the clamping device includes two clamping elements, and the overlap locations may be spaced 120 degrees where the clamping device includes three clamping elements.

The clamping device may include a plurality of clamping elements having the same overlap locations, for example, a pair of axially adjacent clamping elements may have the same overlap locations which may be spaced circumferentially with an overlap of an adjacent pair of clamping elements. In examples of the invention, the clamping device comprises four such pairs of clamping elements, and the overlap locations of the clamping element pairs are spaced 90 degrees apart around the circumference of the tubular shape. This may provide for the application of a substantially equal, radial load to the tubular form, while providing a clamping device of minimal dimensions and weight. In an alternative, axially adjacent clamping elements may have overlap locations spaced circumferentially.

According to a further example, a clamping device is provided for a tubular form, the clamping device comprising: a plurality of friction pads adapted to grip the tubular form and at least one elastic elongated clamping member adapted to exert a force on the friction pads for urging the friction pads to grasp the tubular shape, wherein the friction pads are each arranged to be disposed between the tubular shape and the tensioning member, and wherein the friction pads and tensioning members are arranged to exert a substantially equal, radial, clamping load on the tubular shape, of external loads applied to the clamping device.

By placing the friction pads between the tubular mold and the tensioning element, each of the friction pads can be activated to the same extent by the tensioning elements. This can provide for an equal, radial load on the tubular form without causing the friction pads to transfer point loads on the tubular form, which point loads will result in local folding, either during application of the clamping device to the tubular form or during use when an external load is carried by the clamping device.

The clamping elements may be arranged to pass around a circumference of the tubular mold and may therefore extend around the rear surfaces of the friction pads (relative to the tubular mold) thereby encircling the tubular mold. In a further example, a clamping device is provided for a tubular form, the clamping device comprising: at least one friction pad adapted to grip the tubular form, at least one elastic elongated clamping member adapted to exert a force on the friction pad pressing the friction pad to grasp the tubular form, the friction pad and clamping member being arranged to exert a substantially equal, radial clamping load on the tubular shape, which clamping load is independent of external loads applied to the clamping device and a supporting structure coupled to the relationship to the friction pad, so that an external load exerted on the support structure at a location spaced laterally from a principal axis of the tubular form causes the friction pad to induce a substantially axially directed reaction load in the tubular form.

By coupling the support structure to the friction pad in this way, an external load exerted on the support structure at a location laterally spaced from a principal axis of the tubular (a cantilever load) cannot induce a torque in or around the friction pad. This avoids, or at least minimizes, the generation of reactive, radial point load on the tubular shape due to the external load.

In addition, the support structure does not reverse the radial clamping load which affects the tubular shape. This is unlike, for example, the mechanism of DE 19647515, in which the foot must be able to carry the high load transmitted to the wind turbine tower by using pistons, which requires the foot to be large and, consequently, relatively heavy with associated disadvantages. In known clamping devices and structures, such as the mechanism of DE 19647515, cantilever loads are exerted on a tubular shape, which cantilever loads act back radially with the tower, leading to variations in load around the perimeter of the tubular shape and ultimately to local folding. The clamping device may comprise a plurality of friction pads. Providing a support structure coupled to a plurality of friction pads in this way operatively connects the friction pads to one another, thereby avoiding or at least minimizing any reactive load generated in the tubular form when external load is exerted on the clamping device at a lateral distance from a main axis of the tubular shape. Such reactive loads are especially avoided or minimized when a cantilever load is applied to the support structure (a load supported only at one end). This occurs because the external load is carried by induced, axial, reactive loads in the tubular form, since the friction pads exert loads which alone or mainly aligned parallel to a principal axis of the tubular form. This provides the maintenance of a substantially equal, radial clamping load and thus a substantially equal annular load in the tubular form.

The support structure may be rotatably or pivotally coupled to the friction pads through a hinge, ball joint, or the like, which may provide transfer of a load to the friction pads in a direction parallel to a major axis of the tubular form but substantially preventing transfer of radial loads to due to the external load.

The support structure may include a support member connected to the friction pad to exert an application force on the friction pad to apply the friction pad relative to the tubular form, where a applying force exerted on the friction pad with the support member is released before the friction pad is pressed into the friction pad to press with the clamping element. The support member may be rotatably or pivotally coupled to a frame of the support structure to provide placement of the friction pad. The support means may be arranged to be secured against rotation relative to the frame to allow the frame to support an external load and may therefore be locked or retained before the clamping device is used to support an external load. In a further example, a clamping device is provided for a tubular form, the clamping device comprising: at least one friction pad adapted to grip the tubular shape and at least one elastic elongated clamping member adapted to exert a force on the friction pad for pressing the friction pad to grasp the tubular shape, the friction pad and clamping member being arranged to exert a substantially equal, radial clamping load on the tubular shape, which clamping load is independent of external loads applied to the clamping device wherein the clamping member is arranged to guide about a circumference of the tubular shape and to overlap in one direction at a distance along a principal axis of the tubular shape, and wherein the clamping element is arranged to extend from the overlap position in a direction substantially parallel to a tangent of the tubular shape at the overlap position.

The clamping element is arranged to be tensioned to exert the force on the friction pad. Parts of the clamping member extend away from the tubular form from the overlap position; this provides, among other things, the use of the clamping device with tubes of different diameters, and in particular use of a tubing of varying diameters, since the clamping element is capable of enclosing tubes of different diameters in a region. Arranging the clamping members to extend from the overlap position in a direction substantially parallel to a plunger tangent at that location provides the application of tensile forces to those parts of the clamping member which are aligned substantially parallel to the tangent. This avoids, or at least minimizes, the generation of any torque in the tubular form because: 1) the forces in those parts of the clamping elements which extend away from the tubular form are substantially parallel to the tangent of the tubular form, but directed in opposite directions; and, thus, tensile loads in these parts act back against each other, and 2) since the clamping element substantially surrounds the tubular shape and the clamping member's parts are positioned such that little or no torque is generated around the tubular shape when the clamping element is tensioned.

The clamping member may extend from the overlap position in the first and second opposite directions, each direction substantially parallel to the tangent of the tubular shape. The first and second directions may be within 0 to 10 degrees, preferably 0 and 5 degrees for the tangent, and the term substantially parallel must be interpreted accordingly.

The friction pad may be disposed between the tubular shape and the clamping element, and the overlay placement of the clamping member may be spaced radially between, for example, 5 mm and 50 mm, optionally between 10 mm and 20 mm, from an external surface of the tubular shape, the distance being determined by factors including the thickness of the friction pad.

The clamping member may extend from the overlap position to a disc, block pulley or the like and thence to a play or the like to clamp the clamping member. In a further example, a clamping device is provided for a tubular mold, the clamping device comprising: at least one friction pad adapted to grip the tubular mold, a support member connected to the friction pad to exert an application force on the friction pad to apply the friction pad relative to the tubular shape, and at least one elastic elongate tension member adapted to exert a force on the friction pad to press the friction pad to grasp the tubular shape, the friction pad and tension member being thereby adapted to exert a substantially equal, radial clamping load on the tubular form, which clamping load is independent of external loads applied to the clamping device, where a applying force exerted on the friction pad by the support means is released before the friction pad is pressed to grip the tubular with the clamping member.

Therefore, the friction pad can be positioned relative to the tubular shape by applying a loading force to the friction pad, and the loading force is released before applying a clamping load on the tubular mold. This adjusts the friction pad to the surface of the tubing and prevents or minimizes variation in the load on the tubing due to misalignment of the friction pad relative thereto. This avoids or minimizes the likelihood that the friction pad will create variations in the load on the tubular form, which tends to lead to local folding.

The clamping device may comprise at least one pair of friction pads adapted to be placed over a diameter of the tubular mold and operatively connected so that an external load exerted on the clamping device at a location at a lateral distance from a main axis of the tubular mold causes the friction pads substantially induces axially directed reaction loads in the tubular form. The friction pads may be operatively connected to each other through a support structure coupled to the friction pads, the support structure comprising a support member connected to each friction pad.

The support member may be pivotally coupled to the friction pad, preferably through a ball joint, which prevents a torque from being transferred between the support structure and the friction pad. Alternatively, the support member may be coupled through a hinge. The clamping device may further comprise first and second support members in the form of arms, each arm being pivotally coupled to the friction pad, the first and second arms serving to position the friction pad at a desired radial location relative to a surface of the tubular shape and to position it. a gripping surface of the friction pad substantially parallel to or in the same plane as the surface of the tubular mold.

It should be noted that the support means is coupled to the clamping device to ensure that no clamping force exists in the support means when the clamping device is activated. In a further example, a clamping device is provided for a tubular form, the clamping device comprising: a plurality of flexible friction pads adapted to grip the tubular shape and at least one elastic elongated clamping member adapted to exert a force on the friction pads for pressing the friction pads to grasp the tubular shape, wherein the friction pads and tensioning member are arranged to exert a substantially equal, radial clamping load on the tubular shape, which clamping load is independent of external loads applied to the clamping device, essentially encircling a perimeter of the tubular shape.

By dimensioning the friction pads to substantially surround the tubular shape, the clamping load exerted on the tubular form can be directed through the friction pads. In this way, a substantially complete ring consisting of the friction pads can be formed around the perimeter of the tubular form, which provides for the application of an equal clamping load to the tubular form and reduces the likelihood of generating variations in tubular loading which variations are prone to lead. for local folding. The tubular shape may be tapered along a length thereof and therefore may have varying diameters. The friction pads may be sized to substantially surround the tubular shape at a desired position along a length thereof and may therefore be configured to surround a defined or predetermined perimeter of the tubular shape. The tubular form may be a wind turbine tower and the preferred circumference may be at a desired operating location of the clamping device, which may be an operating height where it is desired to position the clamping device to subsequently perform a desired method. This method may be a maintenance or installation method and may involve supporting an external load from the tower using the clamping device such as when a turbine component is removed for maintenance or subsequently reinstalled.

The dimensions of the friction pad may be adjustable and / or the friction pads may be releasably coupled to a remaining portion of the clamping device to provide removal and replacement with an alternative friction pad. In a further example, there is provided a joint comprising two clamping devices coupled to a coupling providing adjustment of a distance between the clamping devices to provide advance of the joint along a length of a tubular form, the clamping devices each comprising a clamping device. as defined in any of the above examples. In a further example, a self-advancing climbing device is provided for mounting on a tubular column, the assembly comprising two clamping devices coupled to a coupling providing adjustment of a distance between the clamping devices to provide advance of the joint along a length of the column. wherein the clamping devices each comprise a clamping device as defined in any of the above examples.

The tubular column is preferably the tower of a wind turbine. In a further example, there is provided a method of coupling a clamping device to a tubular molding comprising the steps of: placing a clamping device around the tubular molding, the clamping device having at least one friction pad and at least one elastic elongated clamping member, and clamping the clamping member to exerting a force on the friction pad to compress the friction pad to grip the tubular form, thereby applying a substantially equal, radial clamping load to the tubular shape, which clamping load is independent of external loads applied to the clamping device. In a further example, there is provided a method of climbing in a tubular column comprising the steps of: providing a climbing device comprising upper and lower clamping devices coupled to one another by an actuator, each clamping device having at least one friction pad and at least one elastic elongate clamping member, secure the upper clamping device to the tubular form by clamping the respective upper clamping member to exert a force on the respective upper friction pad to press the friction pad to grip the tubular shape, thereby applying a substantially equal , radial clamping load on the tubular shape, which clamping independent of external loads applied to the clamping device, secure the lower clamping device to the tubular shape by tightening the respective lower clamping member to exert a force on the respective lower friction pad to press the friction pad to grip tubular thereby applying a substantially equal, radial clamping load to the tubular form, releasing the upper clamping device from the tubular form, increasing a distance between upper and lower clamping devices by using the actuator to advance the upper clamping device along a length of the tubular shape, retaining the upper clamping device the tubing, releasing the lower clamping device from the tubing, reducing the distance between the upper and lower clamping devices to advance the lower clamping device along a length of the tubing, and securing the lower clamping device to the tubing.

Further examples are: 1. A clamping device for a tubular form, the clamping device comprising: at least one friction pad adapted to grip the tubular shape, and at least one elastic elongated clamping member adapted to exert a force on the friction pad to pressing the friction pad to grasp the tubular form, whereby the friction pad and clamping member are arranged to exert a substantially equal, radial clamping load on the tubular shape, which clamping load is independent of external loads applied to the clamping device. A clamping device according to point 1, which comprises a plurality of clamping elements, the clamping elements being arranged to be spaced in a direction along a principal axis of the tubular form, wherein at least one of the clamping elements is arranged to clamp to exert the force on the friction pad. , of which there is at least one, when applying a pulling force to the clamping element, which is directed in a circumferential direction around the tubular shape opposite that of another of the clamping elements. A clamping device according to any of the points 1 or 2, said clamping device comprising a plurality of clamping members, the clamping members being adapted to clamp to exert the force on the friction pad, of which there is at least one where each clamping member is arranged to is arranged around a perimeter of the tubular shape and to overlap in a distance at a distance along a principal axis of the tubular form, wherein the overlap locations of at least one of the clamping elements are arranged to be spaced about a perimeter of the tubular shape relative to the overlap of a other clamping element. A clamping device according to any of the preceding points, said clamping device comprising a plurality of friction pads, each friction pad being arranged to be disposed between the tubular shape and the clamping element. A clamping device according to any of the foregoing points, said clamping device comprising a support structure coupled to the friction pad, so that an external load exerted during application on the support structure at a location laterally spaced from a main axis of the tubular form causes the friction pad to induce a substantially axially directed reaction load in the tubular form. A clamping device according to item 6, wherein the support structure is coupled to the friction pad so that a cantilever load exerted on the support structure in use induces a substantially axially directed reaction force in the tubular form. A clamping device according to any one of the preceding points, wherein the clamping element is arranged to pass around a circumference of the tubular shape and to overlap in a distance at a distance along a principal axis of the tubular shape, and wherein the clamping element is further arranged to extending from the overlap position in a direction substantially parallel to a tangent of the tubular shape at the overlap position. A clamping device according to any of the foregoing points, said clamping device comprising a support member connected to the friction pad to exert an application force on the friction pad to apply the friction pad relative to the tubular mold, wherein a positioning force exerted on the friction pad with the support member in use is released before the friction pad is pressed to grasp the tubular shape with the clamping member. A clamping device according to any of the foregoing points, said clamping device comprises a plurality of friction pads, the friction pads being resilient and dimensioned to substantially encircle a circumference of the tubular shape. A tubular clamping device, the clamping device comprising: at least one friction pad adapted to grip the tubular shape; and - a plurality of elastic elongate clamping elements adapted to clamp to exert a force on the friction pad; of which at least one, for pressing the friction pad to grasp the tubular shape, the friction pad and clamping elements being arranged to exert a substantially equal radial clamping load on the tubular form, which clamping load is independent of external loads applied to the clamping device, the clamping members are arranged to be spaced in a direction along a principal axis of the tubular shape, and - wherein at least one of the clamping members is arranged to be tensioned by applying a traction to the clamping element directed in a circumferential direction around the tubular shape opposite that of another clamping elements. A tubular clamping device, the clamping device comprising: - at least one friction pad adapted to grip the tubular mold, and - a plurality of elastic elongate clamping elements adapted to clamp to exert a force on the friction pad , of which at least one, for pressing the friction pad to grasp the tubular shape, each clamping member being arranged to pass around a circumference of the tubular shape and to overlap in a distance along a major axis of the tubular shape, the friction pad and clamping member are arranged to exert a substantially equal radial clamping load on the tubular shape, which is independent of external loads applied to the clamping device, wherein the overlap of at least one of the clamping elements is arranged to be spaced about a circumference of the tubular shape in relative to the overlap of another clamping member. A tubular clamping device, the clamping device comprising: a plurality of friction pads adapted to grip the tubular mold, and at least one elastic elongated tension member adapted to exert a force on the friction pads to compress the friction pads to; grasping the tubular form, wherein the friction pads are each arranged to be disposed between the tubular form and the clamping element, and wherein the friction pads and clamping element are arranged to exert a substantially equal, radial clamping load on the tubular shape, which clamping load is independent of external loads. is applied to the clamping device. 13. A clamping device for a tubular form, the clamping device comprising: at least one friction pad adapted to grip the tubular form, at least one elastic elongated clamping member adapted to exert a force on the friction pad to press the friction pad to grip gripping the tubular shape, the friction pad and clamping element being arranged to exert a substantially equal, radial clamping load on the tubular shape, which clamping load is independent of external loads applied to the clamping device, and - a support structure coupled to the friction pad, so an external load applied during application to the support structure at a location laterally spaced from a principal axis of the tubular form causes the friction pad to induce a substantially axially directed reaction load in the tubular form. A tubular clamping device, the clamping device comprising: - at least one friction pad adapted to grip the tubular shape, at least one elastic elongated clamping member adapted to exert a force on the friction pad to press the friction pad to gripping the tubular form, the friction pad and clamping element being arranged to exert a substantially equal, radial clamping load on the tubular shape, which clamping is independent of external loads applied to the clamping device, the clamping element being adapted to pass around a circumference of the tubular shape and to overlap in a distance spaced along a principal axis of the tubular shape, and wherein the clamping member is adapted to extend from the overlap location in a direction substantially parallel to a tangent of the tubular shape at the overlap location. A tubular clamping device, the clamping device comprising: - at least one friction pad adapted to grip the tubular mold, - a support member associated with the clamping means for exerting a frictional pad applying force to the friction pad relative to the tubular mold and at least one elastic elongate tension member adapted to exert a force on the friction pad to press the friction pad to grasp the tubular shape, the friction pad and tension element being thereby adapted to exert a substantially equal, radial clamping load on the tubular mold , which clamping load is independent of external loads applied to the clamping device, in which an application force exerted on the friction pad by the support means is released before the friction pad is pressed to grip the tubular with the clamping member. A tubular clamping device, the clamping device comprising: - a plurality of elastic friction pads adapted to grip the tubular mold and at least one elastic elongated tension member adapted to exert a force on the friction pads to press the friction pads for gripping the tubular form, wherein the friction pads and the tensioning element are arranged to exert a substantially equal, radial clamping load on the tubular form, which clamping load is independent of external loads applied to the clamping device and the friction pads are substantially sized. encircle a perimeter of the tubular shape. A clamping device according to point 2, any of points 3 to 9 in combination with point 2 or point 10, said clamping device comprises a plurality of pairs of clamping members, each pair of clamping elements being adapted to be tensioned by applying tensile forces, which are directed in opposite circumferential directions around the tubular shape. A clamping device according to item 17, wherein the pairs of clamping elements are arranged to be spaced axially with respect to the main axis of tubular one. A clamping device according to point 2, any of points 3 to 9 in combination with point 2 or point 10, wherein axially adjacent clamping elements are arranged to be tensioned by applying pull forces directed in opposite circumferential directions around the tubular shape. A clamping device according to point 2, any of points 3 to 9 in combination with points 2, point 10 or points 17 to 19, the clamping elements each having respective first and second ends, one of the ends being arranged to be coupled in relation to a supporting structure of the clamping device, and the other end is arranged to be coupled to a winch for clamping the clamping element. A clamping device according to paragraph 20, wherein axially adjacent clamping elements are tensioned by applying a traction force at opposite ends. A clamping device according to either point 20 or 21, wherein the first end of one of the tensioning members is tensioned to generate a tensile load in a first circumferential direction around the tubular shape and the respective second end of the tensioning is tensioned to generate a tensile load in a second circumferential direction. around the tube shape opposite the first direction. A clamping device according to point 3, any of points 4 to 9 in combination with point 3 or point 11, wherein the overlap locations for axially adjacent clamping elements are spaced equally spaced around the circumference of the tubular shape. A clamping device according to paragraph 23, wherein the clamping device comprises two clamping elements and wherein the overlap locations are arranged to be spaced 180 degrees around the circumference of the tubular shape. A clamping device according to point 23, wherein the clamping device comprises four clamping members and wherein the clamping overlays of the clamping members are arranged to be spaced 90 degrees around the circumference of the tubular shape. A clamping device according to paragraph 23, wherein the clamping device comprises four pairs of clamping members, the clamping members of each pair being arranged to have the same overlap locations and the pairs' overlap locations being arranged to be spaced about the circumference of the tubular shape. A clamping device according to point 3, any of points 4 to 9 in combination with point 3 or point 11, said clamping device comprising a plurality of pairs of clamping elements, the overlap locations for each pair of clamping elements being arranged to be spaced apart around the perimeter of the tubular relative to another pair of clamping members. 28. A clamping device according to item 27, wherein the pairs of clamping elements are arranged to be arranged so that the respective overlap locations for the pairs of clamping elements are arranged equally spaced around the circumference of the tubular shape. A clamping device according to item 27 or 28, said clamping device comprising four pairs of clamping members, the overlap locations of each pair of clamping elements being spaced at the same distance around the perimeter of the tubular shape. A clamping device according to point 4, any of points 5 to 9 in combination with point 4 or point 12, wherein the clamping element is arranged to pass around a circumference of the tubular shape and therefore extends around the rear surfaces of the friction pads thereby surround the tubing. A clamping device according to point 4, any of points 5 to 9 in combination with point 4 or point 12, said clamping device comprising four friction pads arranged at the corners of a rectangle when viewed from above. A clamping device according to item 6, any of points 7 to 9 in combination with item 6 or item 13, wherein the clamping device comprises a plurality of friction pad pairs disposed over a diameter of the tubular mold, each pair of friction pads disposed with distance around the perimeter of the tubing. A clamping device according to point 32, wherein the clamping device comprises two pairs of friction pads, the friction pads being spaced 90 degrees around the circumference of the tubular mold. A clamping device according to paragraph 32, wherein the clamping device comprises four pairs of friction pads, the friction pads being spaced 45 degrees around the circumference of the tubular mold. A clamping device according to paragraph 6, any of points 7 to 9 in combination with paragraphs 6, 13 or 32 to 34, wherein the clamping device comprises a support structure coupled to the friction pads, so that an external load which when applied to the support structure is exerted at a location laterally spaced from a principal axis of the tubular form, the friction pads induce substantially axially directed reaction loads in the tubular form. 36. A clamping device according to paragraph 35, wherein the support structure is pivotally coupled to the friction pads to prevent a torque transfer between the support structure and the friction pad. 37. A clamp device according to item 35 or 36, wherein the supporting structure is coupled to each friction pad with a ball joint. 38. A clamping device according to any of points 35 to 37, wherein the supporting structure includes a support member connected to the friction pad to exert an application force on the friction pad to apply the friction pad relative to the tubular shape, and wherein an application force used during use. exerted on the friction pad with the support means is released before the friction pad is pressed to grip the tubular shape with the clamping member. 39. A clamp device according to point 38, wherein the support means is pivotally coupled to a frame of the support structure to provide placement of the friction pad. A clamping device according to any of points 38 or 39, wherein the tubular shape is tapered and wherein the clamping device comprises first and second support members in the form of arms, each arm being pivotally coupled to the friction pad, the first arm serving to place the friction pad at a desired radial location relative to a surface of the tubular shape, and the other arm serves to adjust an angle of the friction pad relative to the tubular shape so that the friction pad matches the conical shape of the tubular shape. A clamping device according to point 40 in combination with point 39, wherein the first arm is arranged to be secured against rotation relative to the frame to allow the frame to support an external load. 42. A clamp device according to point 7, any of points 8 to 9 in combination with point 7 or point 14, wherein the clamping member extends from the overlap position in the first and second opposite directions, each of the directions substantially parallel to that of the tubular shape. key. 43. A clamping device according to point 42, wherein the first and second directions are within 0 to 10 degrees of the tangent. 44. A clamp device according to either point 42 or 43, wherein the first and second directions are within 0 to 5 degrees of the tangent. 45. A clamp device according to point 7, any of points 8 to 9 in combination with point 7, points 14, 43 or 44, where the friction pad is arranged between the tubular shape and the clamping element and the overlap position of the clamping element is arranged at a radial distance between 5 mm and 50 mm from an external surface of the tubular mold. 46. A clamp device according to paragraph 45, wherein the overlap position is spaced between 10 mm and 20 mm from the outer surface of the tubular form. 47. A clamp device according to point 7, any of points 8 to 9 in combination with points 7, points 14 or 42 to 46, wherein the clamping member extends from the overlap location to a disc and thence to a play to clamp the clamping member. 48. A clamping device according to any of the preceding points, wherein the friction pad and clamping member are arranged to move radially away from the tubular form and thus retract relative to the tubular shape when the force exerted on the friction pad of the clamping member is applied. is triggered. 49. A clamping device according to any of the preceding points, wherein the tubular form is a wind turbine tower. 50. A clamping device according to any of the preceding points, wherein the friction pad defines a friction gripping surface. 51. A clamping device according to any of the preceding points, wherein the equal, radial load is exerted on the tubular form by direct contact of the friction pad and the clamping element with a surface of the tubular mold. 52. A clamping device according to any of the preceding points, which clamping device comprises a plurality of friction pads and wherein the friction pads are adapted to substantially surround the tubular shape so that the uniform radial load is generated with the clamping element and transmitted through the friction pads to the tubular shape. surface. 53. A clamping device according to any of the preceding points, wherein the clamping element is arranged to be tensioned to exert the force on the friction pad. 54. A clamping device according to paragraph 52, wherein one end of the clamping member is arranged to be secured relative to a supporting structure for the clamping device and the other end is arranged to be connected and tensioned by a winch. 55. A self-advancing climbing device for mounting on a tubular column, the climbing device comprising two clamping devices coupled with a coupling providing adjustment of a distance between the clamping devices to provide advance of the joint along a length of the column, each clamping device comprises a clamping device as defined in any of the foregoing points. 56. An assembly comprising two clamping devices coupled to a coupling providing adjustment of a distance between the clamping devices to provide advance of the assembly along a length of a tubular form, the clamping devices each comprising a clamping device as defined in a any of points 1 to 54. 57. A method of coupling a clamping device to a tubular form, the method comprising the steps of: - placing a clamping device around the tubular shape, the clamping device having at least one friction pad and at least one elastic elongated clamping member; and - clamping the clamping member to exert a force on the friction pad to press the friction pad to grip the tubular form, thereby applying a substantially equal, radial clamping load to the tubular form, which clamping load is independent of external loads applied to the clamping device. 58. A method according to paragraph 56, comprising: - disposing a plurality of spacers at a distance along a principal axis of the tubular shape, and - clamping the clamping elements by applying a traction to at least one of the clamping elements, which is directed. in a first circumferential direction around the tubular opposite to that of a second of the clamping members. 59. A method according to either point 57 or 58, comprising: - disposing a plurality of clamping elements extending around a circumference of the tubular shape so that each clamping element overlaps in a distance along a principal axis of the tubular shape, and - arranging the clamping elements so that the overlap of at least one of the clamping elements is spaced about a circumference of the tubular shape relative to another of the clamping elements. 60. A method according to any of points 57 to 59, which comprises placing a plurality of friction pads between the tubular mold and the tension member. 61. A method according to any of points 57 to 60, which comprises coupling a support structure for the clamping device with respect to the friction pad, so that an external load exerted during use on the support structure at a lateral distance from the a principal axis of the tubular form causes the friction pad to induce a substantially axially directed reaction force in the tubular form. 62. A method according to any one of points 57 to 61, comprising applying the clamping element extending around a circumference of the tubular shape so that the clamping element overlaps in a distance along a major axis of the tubular shape and then clamping element extends from the overlap position in a direction substantially parallel to a tangent of the tubular shape at the overlap position. 63. A method according to any of points 57 to 62, comprising applying a frictional pad application force by using a friction pad coupling member to apply the friction pad relative to the tubular shape and releasing the post-application force. of the load means and before making sure the clamping element applies the force on the friction pad to press the friction pad to grip the tubular shape. 64. A method according to any of points 57 to 63, which comprises selecting a plurality of elastic friction pads which are sized to substantially encircle a circumference of the tubular shape. A method of climbing in a tubular column, the method comprising the steps of: - providing a climbing device comprising upper and lower clamping devices coupled to one another by an actuator, each clamping device having at least one friction pad and at least one elastic member , elongated clamping member, - securing the upper clamping device to the tubular form by clamping the respective upper clamping member to exert a force on the respective upper friction pad to press the friction pad to grip the tubular shape, thereby applying a substantially equal, radial clamping load to the the tubular mold, which clamping load is independent of external loads applied to the clamping device, secure the lower clamping device to the tubular mold by tightening the respective lower clamping member to exert a force on the respective lower friction pad to press the friction pad to grip the tubular mold, thereby applying one in essence an equal radial clamping load on the tubular, triggering the upper clamping device from the tubular form, increasing a distance between the upper and lower clamping devices by using the actuator to advance the upper clamping device along a length of the tubular shape, securing the upper clamping device to the tubular shape, - shorten the clamp from the pipe mold, - shorten the distance between the upper and lower clamp devices by using the actuator to advance the lower clamp along a length of the pipe mold, and - secure the lower clamp to the pipe mold.

However, it will generally be understood that the features of one or more of the above examples may be provided singly or in combination.

According to one aspect of the present invention, there is provided a method of clamping one or more friction surfaces to the external surface of a tubular structure without damaging the structure or the tubular structure by applying a substantially equal, radial load over the tubular structure. perimeter using the apparatus of the first example of the invention.

According to a further aspect of the present invention, there is provided a method of clamping friction surfaces to a thin-walled tubular structure's external surface without damage to the structure or coatings by applying controlled radial load so that the effect on the tubular structure's folding behavior is the same as applying a substantially equal radial load to the entire circumference, thereby enabling the maximum possible axial load to be applied to the fastened clamping device without folding the tubular structure due to the combined axial and radial loads.

According to a further aspect of the present invention there is provided an apparatus for clamping one or more friction surfaces to a tubular structure, the apparatus comprising a frame which can be assembled around the tower structure, means for moving one or more friction surfaces relative to the frame, and means for applying a load to one or more friction surfaces, wherein the friction surfaces and means for applying load to the friction surfaces are adapted to apply a substantially uniform radial tension load to the tubular structure.

The apparatus preferably imposes a substantially equal, radial load over the entire circumference of the tubular structure.

The apparatus may preferably be arranged according to variations in circumference and cone shape along the length of the tubular structure.

The friction surface, of which there is one or more, is preferably friction pads.

The friction pad, of which there is one or more, is preferably made of a metal or composite material.

The friction pad, of which there is one or more, preferably has at least one surface made of natural or elastomeric friction material, which surface faces the tubular structure.

The friction pad, of which there is one or more, is preferably flexible and adapts to the shape of the tubular structure.

The means for moving the friction surface, of which there is one or more, relative to the frame typically comprises one or more load arms.

Moving the load arm in a first direction acts to bring the friction surface into contact with the surface of the tubular structure. Moving the load arm in a different, opposite direction brings the frictional surface out of contact with the surface of the tubular structure.

Beams of the load arms, of which there are one or more, are preferably moved by the action of a hydraulic cylinder.

Prongs of the friction surfaces, of which there are one or more, are preferably connected to a loading arm.

Prongs of the friction surfaces, of which there are one or more, preferably have a reinforcement to which the loading arm is connected. In one embodiment, the means for applying a radial load to the one or more friction surfaces comprises one or more tension elements. Most clamping members typically take the form of an elastic elongated object to which load can be applied.

The clamping elements can be made of a suitable material such as fiber rope, steel rope, belt, chain or steel strip.

The clamping elements, of which there are one or more, are preferably passed around the entire circumference of the tubular structure.

Typically, the clamping members, of which there are one or more, are passed around the entire circumference of the tubular structure, so that frictional surfaces are disposed between the surface of the tubular structure and the clamping members, of which there is one or more.

Preferably, the reinforcement for each friction surface, of which there is one or more, has openings through which the tensioning elements, of which the deflector or more, can be passed.

Each of the load arms preferably has at least one winch which can be used to clamp the tensioning elements, of which there is one or more. Where the tensioning members are tensioned by applying the play, a radial load is applied to the friction surface so that it is pressed against the tubular structure. Close contact between the friction surfaces, of which there is one or more, and the tubular structure can preferably be maintained in spite of the tubular structure's diameter and cone shape angle with a lever system applied by force actuators together with deflection of the friction pads under the influence of the radial load. , which is applied by the tensioning elements, of which there is one or more. In another embodiment, the means for applying a radial load to the friction surfaces, of which there is one or more, comprises a circumferential series of linear actuators.

Twelve or more linear actuators are preferably provided in the series.

The linear actuators optionally act unanimously to apply equal load to the friction surfaces, one or more of which are distributed around the perimeter of the tubular structure through connectors attached to the frame which is assembled around the tubular structure.

Alternatively, the linear actuators act unanimously to apply a straight load to friction pads evenly distributed around the perimeter of the tubular structure with direct radial displacement, the load acting back against the frame assembled around the tubular structure. In a further embodiment, the means for applying a load to the friction surfaces, of which there is one or more, comprises a bladder.

The bladder preferably surrounds the tubular structure.

The bladder can take the form of a tube with closed ends.

Means may also be provided to change the length of the bladder tube. The means for changing the length of the bladder tube is preferably a roller.

The bladder is internally pressurized with a fluid.

The bladder is optionally made of a material with a Poisson's ratio sufficiently high to allow radial expansion to produce a sufficient circular shortening (for example, approaching 1), so that changes in the circumference of the tubular structure can be accommodated by changing the geometry of the bladder. change the amount of blister material used to enclose the tubular structure.

The bladder is preferably retained at its outer diameter by the frame assembled around the tubular structure. In a further embodiment, the means for applying a radial load to the friction surfaces, of which there are one or more, one or more wedges acting on arms, connecting joints or pistons adapted to move the friction surfaces, of which there are one or more , radially to the surface of the tubular structure.

Each of the friction surfaces, of which the drier or more, may also be connected to a rectifier. The upright member typically takes the form of an arm which is connected to the opposite end of the reinforcement relative to the load member. The alignment arm is preferably moved by means of a hydraulic cylinder.

The angle between the vertical and the friction surface can be changed by the movement of the upright arm. Lifting and operating tools may be attached to the appliance.

Apparatus for carrying men may be attached to the apparatus.

A system comprising a first apparatus and a second apparatus according to the present invention, wherein the first apparatus is attached to the second apparatus by linear actuators aligned in line with the axis of the tubular structure so that the first and second apparatus may be spaced apart or pulled apart.

The movement and clamping of the first and second apparatus may be coordinated to produce a linear movement of the joint along the axis of the tubular structure.

The first and second apparatus may be used to transport objects parallel to the axis of the tubular structure.

According to a further aspect of the present invention, there is provided a method of clamping one or more friction surfaces to the outer surface of a tubular structure without damage to the structure or the tubular structure surface upon application of a substantially equal radial load across the perimeter of the tubular structure. by using the apparatus according to the second aspect.

The tubular structure is typically thin-walled.

The tubular structure may be a wind turbine tower.

By applying a substantially equal radial load over the perimeter of the tubular structure, a larger axial load can advantageously be applied to the friction pads without folding the tubular structure due to the combined axial and radial loads.

According to a further aspect of the present invention, there is provided a method of increasing the axial load capacity of a friction clamp device used on a wind turbine tower by increasing the folding capacity of the tower without substantially altering the natural frequency of the tower.

The folding capacity of the wind turbine tower is preferably increased by the use of internal bracing rings.

The stiffening rings are preferably made of a steel or plastic composite material.

The stiffening rings are optionally held in place by friction. Alternatively, the bracing rings are held in place with adhesive or welding.

Embodiments of the present invention will now be described by way of example only with reference to the following drawings, in which

FIG. 1 is a perspective view of a clamping device according to an embodiment of the present invention, the clamping device being shown after coupling to a pipe form in the form of a wind turbine tower;

FIG. 2 is an enlargement of a friction pad and a portion of a supporting structure forming part of the clamping device of FIG. 1

FIG. 3 is an enlargement of the friction pad and a tension member forming part of the clamping device of FIG. 1

FIG. 4 is a further enlargement of the friction pad and tension element shown in FIG. 3, with certain parts shown in brief for illustrative purposes,

FIG. 5 is a schematic drawing of the clamping device of FIG. 1 shown in use supporting an external load, and

FIG. 6 shows an assembly comprising two of the clamping devices of FIG. 1 coupled together, the joint being shown in advance along the length of a tubular form in the form of a wind turbine tower.

As described below, the apparatus and method of the present invention offer significant advantages over prior tubing clamping devices and over known mechanisms coupled to thin-walled tubes, particularly wind turbine towers.

Referring to FIG. 1, there is shown a clamping device / apparatus 1 for a tubular shape which, in the illustrated embodiment, takes the form of a thin-walled conical wind turbine tower 3. The clamping device 1 comprises at least one friction pad 9 arranged to grip the tower 3 and which is shown in greater detail on the magnification of FIG. 2. The clamping device 1 also comprises at least one elastic elongated clamping member 16, which is shown in more detail in FIG. 3. The clamping member 16 is arranged to exert a force on the friction pad 9 to force the pad 9 to grip the tower 3 so that the friction pad 9 and the clamping member 16 exert a substantially equal, radial clamping load on the tubular mold. The friction pad 9 thereby restrains the clamping device 1 from movement relative to the tower 3 in a direction along a length thereof, which makes it possible to support an external load from the tower 3 by using the clamping device 1.

Using the clamping device 1 to exert a substantially equal radial clamping load on the tower 3 provides the generation of a substantially equal ring load in the tower. This solves problems associated with known clamping devices and other mechanisms by avoiding or at least minimizing variations in the load around the perimeter of the tubular form, thereby avoiding or reducing the probability of varied point loads leading to local folding.

It is also to be understood that the method described herein dramatically improves the performance of a clamping device by applying the greatest possible radial loads to friction pads through the application of uniform radial load so that the circular shape of a thin walled tubular structure is maintained. These loads are far greater than the performance of discreetly loaded cushions currently used.

In more detail, the clamping device / apparatus 1 comprises a support structure 22 having a substantially rectangular lower annular boom 2 assembled around the base of the tower 3, a plurality of posts or vertical columns 4, and a substantially rectangular upper annular boom 5. upper annular boom 5 is typically attached to the top of vertical columns 4 at each corner to provide a rigid, approximately cube-shaped skeleton 6 surrounding the tower 3.

Each of the vertical columns 4 is connected at its top end to a first supporting member or rigid load arm 7, which is moved by a hydraulic cylinder 8 connected between the vertical column 4 and the arm 7 as shown in FIG. 2. In the preferred embodiment shown in the drawings, the clamping device comprises four friction pads 9 spaced equally around a circumference of the tower 3. The friction pads 9 are made of a resilient, natural or elastomeric friction material such as neoprene rubber or polyurethane, which is attached to a rigid but flexible sheet of metallic or composite material to which a load may be applied, such as a sheet of steel, which plate has vertical, rigid reinforcements 10 in its center. The reinforcements 10 are each pivotally connected at their upper ends to the lower end of a respective arm 7 via a hinge or ball joint 24. A ball joint is preferred over a hinge as the ball joint provides transfer of a load on the friction pads in a direction parallel to a major axis. for the tubular form but essentially prevents transfer of radial loads to the friction pads due to the external load.

The arms 7 are again pivotally attached to the vertical columns 4 in a manner which allows them to rotate relative to the tower. With this device, the load arms 7 are coupled to the friction pads 9 to provide an application force to the friction pads 9, whereby movement of the load arm 7 causes the respective friction pad 9 to abut and / or contact the surface of the tower 3. This allows the friction pads 9 to contact the surface of the tower 3 and to take up the cone shape angle or to be vertically oriented as appropriate.

The support structure 22 also includes a second support member or upright arm 11 connected to each friction pad 9, each upright arm 11 being pivotally connected to the respective vertical column 4 through a connecting link 13 via a pivot pin 26. The arm 11 is also pivotally coupled to the pad 9 at the lower end of the reinforcement 10 (i.e., at the end of the reinforcement 10 opposite the end to which the loading arm 7 is connected). A second hydraulic cylinder 12 is connected between the vertical column 4 and the pivot pin 26 and thus acts to move the connecting link 13. Accordingly, the angle between the vertical column 4 and the pad 9 can be changed to suit different tower cone shape angles by extending or retracting the connecting cylinder 12. Therefore, the position of the friction pads 9 relative to the tower 3 can be adjusted using a combination of the load arm 7 and the upright arm 11 so that the clamping device 1 can be adjusted to accommodate variations in the circumference / diameter and cone shape angle of the tower 3. This therefore provides the use of the clamping device 1 for towers of different diameters, and especially for towers having cone shape along their length.

As shown in FIG. 3, the clamping device includes a plurality of clamping members, and in the embodiment shown, eight clamping members 16, two clamping members 16 associated with each load arm 7 of the clamping device 7 are included. Each clamping member 16 is tensioned by a respective winch 15 and two such winches 15 are mounted. on each load arm 7. This device allows the clamping elements 16 to compensate for the change in the circumference of the tower 3. Each tension member 16 is guided from an anchor point on load arm 7 or winch 15 and extends through ports 14 in reinforcement 10 for each pad 9 and back to winch 15 on the same load arm 7. Two tension members 16 originate and consequently end at each load arm 7.

The clamping elements 16 each circle the circumference of the tower 3 and thus cross and overlap in a direction along a length of the tower 3 at an overlap 38. As shown in more detail in the further enlargement of FIG. 4, the friction pads 9 are each disposed between the surface of the tower 3 and the clamping members 16, and the clamping members overlap or intersect at the reinforcement 10 of the cushion 9 attached to the respective load arm 7 so that the clamping member 16 is in contact with the tower 3 or cushion 9 when it is carried around the perimeter of the entire tower 3. The clamping elements are typically made of fiber rope, wire, belt, chain or steel with low friction and high performance. Discs 17 are provided to rotate the clamping member 16 from its circumferential passage to the anchor point and winch 15.

As the tension members 16 are tensioned by the pins 15, the tension members exert a force on the friction pads 9 to force the friction pads to grip the tower 3. When the clamping device 1 is securely coupled to the tower 3, the friction pads 9 serve to hold the clamping device back in axial motion. relative to the tower 3 and thus, as indicated above, provides a contact force providing sufficient friction to support usable axial load.

Actually, the tensioning members 16 are arranged around the outside of the friction pads 9 so that when they are pulled tight they "pull" the friction pads towards the tower 3, and the friction pads 9 and tensioning members 16 transfer a substantially equal radial clamping load on the tower 3. This induces as close as practicable a true ring load in the tower 3.

The clamping load on the tower 3 is released by releasing the winches 15, thereby releasing or reducing the force exerted on the friction pads 9 by the tensioning elements 16. The cylinders 8,12 are then moved to move the load and alignment arms 7 and 11 and therefore the friction pads 9 away from the tower 3. This movement carries the clamping elements 16 which are further slackened as required so that the clamping elements 16 can be pulled free from the tower surface.

The friction pads 9 are sized to contact almost the entire circumference of the tower 3 at or toward the top of the tower, while the friction pads at locations toward the bottom of the tower 3 are separated due to the increased diameter of the tower, as shown in FIG. First

There is a further detailed description of the construction and method of operating the clamping device of the present invention and of the consequent advantages offered during operation of the clamping device.

As noted above, the friction pads 9 are positioned between the tower 3 and the tensioning members 16, which enable each pad 9 to be actuated to the same degree with the tensioning members 16. This provides for the generation of an equal, radial load on the tower 3 without causing the friction pads 9 to transmit. point loads on the tower 3, which would lead to local folding, either during placement of the clamping device 1 on the tubular form or in use when an external load is carried by the clamping device 1.

As noted in FIG. 1 to 4, the clamping device 1 includes two pairs of friction pads 9, each pair being arranged over a diameter of the tubular shape, so that each pad 9 is spaced 90 degrees apart. The friction pads 9 are operatively connected to each other in an axial coupling through the support structure 22, since the friction pads 9 are each pivotally coupled to the arms 7 and the arms 7 are pivotally connected to the vertical columns 4. This avoids or at least minimizes any reactive radial load generated in the tower 3 when an external load A is applied to the clamping device 1 at a lateral distance from a main axis 32 of the tubular shape (a cantilever load), as shown in FIG. 5, there is a schematic illustration of the clamping device 1 in use. Such a load A can be exerted on the clamping device 1, for example, during the construction of the tower 3, or during maintenance when a load, such as a section of the tower 3, is lifted by using a crane or the like connected to the clamping device 1.

This is because the external load A generates axial loads F1 and F2 on the friction pads 9, which load thereby induces reactive loads in the tower 3, which are directed parallel to the main axis 32 of the tower 3. Thus, the friction pads 9 exert loads that are clean or in substantially aligned parallel to the tower main axis 32. This axial coupling provides maintenance of a substantially equal, radial clamping load and thus a substantially equal ring load in the tower.

In addition, as noted above, the tensioning members 16 are tensioned to exert a force on the friction pads 9 to generate the uniform radial clamping load. As shown in FIG. 4, tendon members 34 and 36 of each clamping member 16 extend away from tower 3 from an overlap location 38 in a direction substantially parallel to a tangent T to tower 3 at that location. Through this device, a pulling force is exerted on the tensioning members 16, which pulling force is directed substantially parallel to the tangent as the coils 15 are moved to tension the tensioning members 16.

This avoids or at least minimizes the generation of any torque in the tower 3 because: a) the forces in the tendon members 34, 36 of the clamping elements 16, which extend away from the tower 3, are parallel to the tangent T but directed in the opposite direction; directions, and thus tensile loads in the tendon members 34, 36 react to each other, and b) since the tension members 16 substantially surround the tower 3, and the tendon members 34, 36 are thus disposed, little or no torque is generated around the tower 3 when the tension elements 16 are tense. To provide this, the friction pads 9 are made as thin as possible so that the overlap 38 is as close as possible to the surface of the tower 3. The pad thickness 9 may be in the range of 5 to 50 mm, typically 10 to 20 mm, to achieve this. Lower discs 40 are also similarly arranged as close as possible to the rear surface of the friction pads 9 to allow the tendon members 34, 36 to be oriented substantially parallel to the tower key T.

However, it will be appreciated that while it is desired that the tendon portions 34, 36 extend from the overlap 38 in directions substantially parallel to the tower tangent T, the tendon portions may be oriented within, for example, 0 to 10 degrees of the tangent and still act to generate a the substantially equal, radial load on the tower 3.

In addition, it will be appreciated that some variation in the tension force of the tension members 16 may occur along the length of the tension member due to friction between the tension member 16 and the surface of the tower 3. In particular, the inventors have found that the tensile force of the tension members 16 may be greatest closest to the point of application of the traction (play 15) and decrease along the length of the tension member 16 away from the point of application of the load.

As a result, a number of clamping elements 16 are tensioned by the application of tensile forces directed in opposite circumferential directions around the tower 3 to other clamping elements. In this way, variations in the radial loads exerted on the tower 3 by the clamping device 1 (and thus in induced ring load) can be avoided or at least minimized due to variations in the tensile force of the tension members 16.

To achieve this, the tensioning members 16 are tensioned by applying tensile forces at opposite ends. Thus, the first end of one of the tensioning members 16 is tensioned to generate a pulling force in a first circumferential direction around the tower 3, and the respective second end of a second tensioning member 16 is tensioned to generate a tensile load in a second circumferential direction around the tower 3 opposite the one. first direction. For example, each pair of clamping elements 16 connected to a respective arm 7 can be clamped in a first circumferential direction around the tower. The pairs of axially adjacent clamping elements 16 (relative to the main axis 32) are tensioned in the opposite circumferential direction. This has the effect of balancing all variations in load of the individual clamping members 16. In another embodiment, axially adjacent clamping members 16 can be tensioned in opposite circumferential directions. Accordingly, the tensioning members 16 of the pair connected to each arm 7 can be tensioned in opposite directions.

In addition, the overlap locations 38 for a plurality of tension members 16 are spaced around the circumference of the tower to provide minimization of variations in the resulting radial load on the tower 3 and thus minimize variations in the induced ring load. In the illustrated embodiment, the overlap locations 38 for the pairs of clamping elements 16 connected to each arm 7 are spaced apart from the overlap locations 38 for an adjacent pair of clamping elements 16. In particular, the overlap locations 38 for the pairs of clamping elements 16 are spaced equally at 90 degree intervals around the perimeter of the tower. This provides for the application of a substantially equal, radial load to the tower (by balancing variations over a number of adjacent clamping elements 16) while providing a clamping device 1 of minimal dimensions and weight. In one variation, the overlap of axially adjacent tension members 16 may be spaced in a similar manner around the perimeter of tower 3.

In addition, as described above, the friction pads 9 are positioned relative to the tower 3 by exerting a force on the friction pads 9. This application force is released prior to the application of a clamping load on the tower, which adjusts the friction pads 9 to the surface of the tower 3 and prevents or minimizes the load. on the tower 3 around its perimeter by preventing misalignment of the friction pads 9 on the surface of the tower 3. This avoids or minimizes the likelihood of friction pads 9 generating non-uniform point loads that can lead to local folding of the tower 3.

In addition, the friction pads 9 are sized to substantially surround the tower at a certain circumference. This may be at a desired operating location of the clamping device 1, which may be an operating height where it is desired to position the clamping device 1 to subsequently perform a desired method. The method may be a maintenance or installation method and may involve supporting an external load from the tower 3 by using the clamping device 1, such as when a turbine component is serviced or subsequently reinstalled.

Therefore, it will be appreciated that the clamping load exerted on the tower 3 at this location is directed through the friction pads 9. Accordingly, a substantially whole ring comprising the friction pads 9 is formed around the circumference of the tower 3, which provides for the application of an equal clamping load on the the tower and reduces the likelihood of generating variations in load on the tower 3, which tends to lead to local folding.

In addition, the clamping device 1's support structure 22 is effectively locked when in an operating location and before any external load is supported from the clamping device. This is accomplished by locking the arms 7 by using the cylinders 8 when the friction pads 9 have been pressed to grip the tower 3 by the clamping members 16. This hard effect enables the clamping device 1 to support a cantilever load without causing any part of the skeleton 6, such as the upper annular boom 5, comes into contact with the tower 3. However, the pivotal connection between the arms 7 and the friction pads 9 ensures that clean or primarily axial loads are transferred to the friction pads 9.

This also has the effect of triangulating the skeleton 6 with respect to the tower 3, as best shown in FIG. 5, which generates the axial loads F1, F2 in the friction pads 9 and thus the reactive axial loads in the tower 3.

Referring to FIG. 6, an assembly in the form of a self-advancing climbing device 28 coupled to the tower 3 is shown, which climbing device is shown during advance of the climbing device 28 along the length of the tower 3. The climbing device 28 comprises two clamping devices 18 and 19 of similar construction and operation as the clamping device 1 in FIG. 1 to 5. The clamping devices 18, 19 are coupled to an actuator 20 which comprises a plurality of linear actuators providing adjustment of a distance between the two clamping devices 18, 19 to advance the device along the tower 3. The actuators 20 may be hydraulic rams. , telescopic box means moved by a rack, screwdriver and bolt, winches and wires, or any suitable means.

In more detail, the climbing device 28 is arranged around the tower 3, typically near the foot of the tower 30. The climbing device 28 is moved to advance along the length of the tower 3 and thus climb into the tower as follows. First, the upper clamping device 18 is moved and thus connected to the tower 3 in the manner described above. The actuators 20 are initially in a retracted configuration or condition, so that the distance between the clamping devices 18, 19 is relatively small. The lower clamping device 19 is then coupled to the tower 3 in the same way, the upper clamping device 18 is released from the tower 3 and the actuators 20 are stretched to increase the distance between the clamping devices 18 and 19, thereby advancing the upper clamping device 18 a distance along the length of the tower 3.

The upper clamping device 18 is then reconnected to the tower 3, the lower clamping device 19 is released, and the actuators 20 are contracted to reduce the distance between the clamping devices 18,19. This hard effect of advancing the lower clamping device 19 a corresponding distance along the length of the tower 3. The lower clamping device 19 is then reconnected to the tower 3, and the device is thereby advanced a certain distance up the tower. The process is repeated until the climbing device 28 reaches a desired operating height at a particular location along the length of the tower 3. The clamping devices 18,19 are then both clamped to the tower and locked, and an increased operating clamping load is applied to the tower through each of the clamping devices 18, 19. This operating clamping load is higher than that applied while the climbing device 28 climbs into the tower 3. The increased clamping load is generated by applying greater tensile loads to the clamping elements 16 by using the winches 15. The reason for this is that the device only has to exert a sufficient clamping load to securely connect the climbing device 28 to the tower to carry the weight of the device, while the climbing device 28 climbs into the tower 3. However, a greater clamping load is required when it is desired to support an external load from the climbing device 28 to ensure that a sufficiently large frictional force exists between the friction pads 9 and the surface of the tower 3 to maintain the position of the climbing device 28. The clamping load is determined depending on the weight of clamping device 1 / climbing device 28 and the load to be supported, and will typically be set at 5 times the probable total weight carried, assuming a coefficient of friction between the friction pads 9 and the surface of the tower 3 of about 0.2 . Thus, the climbing device 28 can be used during the construction of the tower to carry additional tower sections or other turbine components, as well as in a maintenance process. To provide this, a suitable platform, crane and the like are mounted on the support structures for one or both clamping devices 18,19. In general terms, the apparatus described herein allows friction surfaces or pads to be clamped to a thin-walled tubular structure, such as a wind turbine, without deformation or damage to the structure. This is achieved by the application of controlled radial load so that the effect on the folding behavior of the tubular structure is the same as that of applying a substantially equal, radial load to the entire circumference of the tubular structure. In FIG. Figures 1 to 5 describe a way in which an axial load can be applied to the friction surfaces 9, while a substantially equal radial clamping load can be applied over the perimeter of the tubular structure. In an alternative embodiment, a torus-shaped bladder is installed around the perimeter of the tower with the friction pads inserted between the bladder and the outer surface of the tower. Radial force is applied by pressurizing a fluid, such as air, within the bladder to produce an equal, radial force over the circumference of the tower and the friction pads which can then be axially loaded.

The bladder may be arranged as a closed-end tube, which tube is passed from a fixed point around the tower and back to the fixed point where it is wound on a roll to allow the reduction in the circumference of the tower as it is tapered toward the top. Pressing the bladder is done from the fixed end while the roller is attached to the opposite end. In another alternative embodiment, the bladder is made of a material with a high Poissons ratio (the ratio of deformation in the direction of the applied load to the deformation perpendicular to the load, or ratio of transverse contraction deformation to longitudinal extension deformation in the direction of the tensile force) so that it extends under pressure. causes the circumference of the torus to be significantly reduced, thereby avoiding the need for a tensioner roller, and applying radial load to the friction pads, which can then be axially loaded. In a third alternative embodiment, a series of lever systems operated by linear or rotary actuators are mounted on a circular boom or skeleton so that the levers apply radial force to friction pads which can then be axially loaded.

Where relatively heavy external loads are to be supported by the climbing device 28, the required clamping force in the clamping members 16 to generate a sufficient clamping load can induce a greater deflection in the tower than it is capable of supporting. In other words, the loads that can be applied may be limited by the ability of the tower 3 to withstand global folding under the combined influence of radial load from friction pads 9 / tension members 16 and potentially compressive or shear loads from the climbing system's own weight or loads suspended. from there. The capacity of the tower 3 can be increased by the installation of bracing rings within the tower, which bracing rings are placed in places where the clamping devices will apply radial pressure. These can be constructed from relatively light T-rolled rollers to form a corresponding boom in combination with the adjacent shell of the tower. The T-iron can be held in place by welding or preferably by bonding with adhesive component. These will form part of the manufacturing process for the tower 3. At the larger diameters, vertical ribs will be arranged at the same distance around the part of the tower that is not covered by the friction pads. These will ensure that the radial load transmitted by the tension members 16 is transferred to the internal ring struts and thence to the shell of the tower.

These tools can then be used onshore or offshore for the maintenance of wind turbines.

The clamping device 1 and self-climbing climbing device 28 of the present invention have the inherent advantage of being able to grip towers of varying diameters and varying cone shape angles from parallel to 5 degrees of cone shape or more. In particular, the self-climbing device may be arranged to accommodate variations in circumference and cone shape along a length of the tubular structure. In the embodiment shown in the figures, the pins 15 can be used to clamp the clamping elements 16 which are passed around the tubular structure so that the length of the clamping elements can be changed to maintain a suitable radial force on the tubular structure, even though the circumference of the structure or diameter changes. In the embodiment where a bladder is used, a roller may be provided which allows the circumference of the bladder to be increased or decreased in line with the circumference of the tower. The bladder may alternatively be made of a material with a high Poisson ratio, which eliminates the need for a roll.

The apparatus is also capable of grasping a very thin tower without inducing folding, as the clamping elements apply a substantially equal load over the entire circumference of the tubular structure. The method and apparatus described herein allow the maximum possible axial load to be applied to the fastened clamping device without folding of the tubular structure due to the combined axial and radial forces. It is therefore particularly suitable for wind turbine towers.

Further modifications and improvements may be included without departing from the scope and scope of the invention contemplated herein.

Claims (30)

An apparatus (1, 18, 19) for clamping one or more friction surfaces (9) against a tubular structure (3), wherein the apparatus (1, 18, 19) comprises a frame (22) which can be assembled around it. tubular structure (3), means for moving one or more friction surfaces (9) relative to the frame (22), and means for applying a load to one or more friction surfaces (9), characterized in that the friction surfaces (9) and the means for applying load to the friction surfaces (9) are adapted to apply a substantially uniform radial tension load to the tubular structure (3). Apparatus (1, 18, 19) according to claim 1, wherein one or more friction surfaces (9) are friction pads (9). Apparatus (1, 18, 19) according to claim 2, wherein the one or more friction pads (9) are made of metal or a composite material. Apparatus (1, 18, 19) according to claim 2, wherein the one or more friction pads (9) have at least one surface made of a natural or elastomeric friction material, the surface facing the tubular structure (3) · Apparatus (1, 18, 19) according to any one of claims 2-4, wherein the one or more friction pads (9) are flexible and adapt to the shape of the tubular structure (3). Apparatus (1,18,19) according to any one of the preceding claims, wherein the means for moving one or more friction surfaces (9) relative to the frame (22) comprises one or more load arms (7). Apparatus (1, 18, 19) according to claim 6, wherein movement of the load arm (7) acts in a first direction to contact the friction surface (9) with the surface of the tubular structure (3) and movement of the load arm (7). ) in another opposite direction brings the friction surface (9) out of contact with the surface of the tubular structure (3). Apparatus (1, 18, 19) according to claim 6 or 7, wherein each of the load arms (7), of which there is one or more, is moved by actuation from a hydraulic cylinder (8). Apparatus (1, 18, 19) according to any one of the preceding claims, wherein the means for applying a load to one or more friction surfaces (9) comprises one or more clamping elements (16). Apparatus (1, 18, 19) according to claim 9, wherein each clamping element (16) is typically in the form of an elastic elongated object to which load can be applied. Apparatus (1, 18, 19) according to claim 9 or 10, wherein the clamping elements (16) are made of steel rope. Apparatus (1, 18, 19) according to any one of claims 9-11, wherein the one or more clamping elements (16) are guided around the entire tubular structure (3) so that friction surfaces (9) are arranged between the surface of the tubular structure (3) and one or more clamping elements (16). Apparatus (1, 18, 19) according to any one of claims 9-12, wherein the one or more friction surfaces (9) is supported by a reinforcement (10) having apertures through which one or more tensioning elements (16) fed. Apparatus (1, 18, 19) according to any one of claims 9-13, wherein the means for applying a radial load to one or more friction surfaces (9) comprises at least one coil (15) which can be used for tensioning the one or more clamping elements (16). Apparatus (1, 18, 19) according to any one of claims 1-13, wherein the means for applying a load to one or more friction surfaces (9) comprises one or more linear actuators (20). Apparatus (1, 18, 19) according to claim 15, wherein there is a plurality of linear actuators (20) which act unanimously to apply equal load to one or more friction surfaces (9) distributed around the tubular structure (3) circumferentially through connecting links attached to the frame (22). Apparatus (1, 18, 19) according to claim 15, wherein there is a plurality of linear actuators (20) which apply an equal load to one or more friction surfaces (9) by direct radial displacement, the load acting back toward the frame (22). Apparatus (1, 18, 19) according to claim 15, wherein the linear actuator (20) comprises a bladder. Apparatus (1, 18, 19) according to claim 18, wherein the bladder surrounds the tubular structure (3). Apparatus (1, 18, 19) according to claim 18 or 19, wherein the bladder comprises a closed-end tube. Apparatus (1, 18, 19) according to any one of claims 18 - 20, wherein means are provided for changing the length of the bladder tube. Apparatus (1, 18, 19) according to claim 18, wherein the means for changing the length of the bladder tube is a roller. Apparatus (1, 18, 19) according to any one of claims 18-22, wherein the bladder is retained at its outer diameter by the frame (22) assembled around the tubular structure (3). Apparatus (1,18,19) according to any one of the preceding claims, wherein the means for applying a load to one or more friction surfaces (9) comprises one or more wedges acting on arms (7, 11), connecting joints (13) or pistons arranged to move one or more friction surfaces (9) radially toward the surface of the tubular structure (3). Apparatus (1, 18, 19) according to any one of the preceding claims, wherein at least one of the friction surfaces (9), of which there is one or more, is connected to a straightening arm (11), the angle between the vertical and the friction surface (9) ) can be changed by the movement of the upright arm (11). Apparatus (1, 18, 19) according to claim 25, wherein the upright arm (11) is moved by a hydraulic cylinder (12). Apparatus (1,18,19) according to any one of the preceding claims, wherein the means for applying a load to one or more friction surfaces (9) comprises means for applying a radial load to one or more friction surfaces ( 9). System comprising a first apparatus (18) and a second apparatus (19) according to any one of the preceding claims, characterized in that the first apparatus (18) is fixed to the second apparatus (19) with linear actuators (20), aligned in parallel with a longitudinal axis of the tubular structure (3) such that the first apparatus (18) and the second apparatus (19) may be spaced apart or contracted. A method of clamping one or more friction surfaces (9) against a tubular structure (3), which comprises assembling a frame (22) around the tubular structure (3) and moving one or more friction surfaces (9). ) relative to the frame (22), characterized in that the method further comprises applying a load to one or more of the friction surfaces (9) to clamp the friction surfaces (9) to the tubular structure (3) with a substantially uniform, radial tension load. An apparatus (1,18,19) for clamping one or more friction surfaces (9) against a tubular structure (3), wherein the apparatus (1, 18, 19) comprises a series of rod systems driven by linear (20) or rotary actuators and arranged on a circular frame such that the rods apply a radial force to the friction surfaces (9), characterized in that the friction surfaces (9) and the rods are adapted to apply a substantially uniform radial tension load to the tubular construction (3).