Patent Description:
From <CIT>, such a blade access arrangement is known, where sub-platforms are connected by means of swivel joints and surround an opening through which a rotor blade can be accommodated. When the shape of the platform is changed, the angular relation of the sub-platforms with respect to the rotor blade is changed.

<CIT> discloses a suspendable maintenance platform for accessing a blade of a wind turbine. The platform includes arms for holding a maintenance unit, a frame onto which each arm is movably attached in a joint enabling planar movement, and means for supporting the frame in relation to the wind turbine tower. The maintenance unit is slidably attached to the arms that are configured for positioning the platform in relation to the blade, and wherein the frame is configured to be in close proximity to the turbine tower.

<CIT> discloses an inspection device for a rotor blade having a maintenance chamber through which a rotor blade can pass vertically through a floor opening and a roof opening. The maintenance chamber is arranged on a supporting frame, and the supporting frame is connected to a bracing frame, which bracing frame can be supported on the tower of the wind turbine. By moving the bracing frame, and thereby the maintenance chamber, relative to the supporting frame it is possible to turn the maintenance chamber in relation to the rotor blade running through the maintenance platform.

The document <CIT> discloses a blade access arrangement according to the preamble of claim <NUM>.

The object of the invention is to provide a blade access arrangement where the platform can access the blade tip, which is positioned in a distance from the tower greater than other parts of the blade and where the platform can be manoeuvred in relation to the tower and the blade.

This object is solved by a blade access arrangement according to claim <NUM>.

Hereby it is possible to change shape of the platform by changing the configuration of the sub-platforms in relation to each other. For example widening the shape of the platform.

In an embodiment, the displaceable connections are connected to each other by a drivetrain comprising a flexible member being flexible around its longitudinal axis and a pulley.

In alternative embodiments, the drivetrain can be one or more racks, belts, toothed belts, threaded spindles or combinations thereof.

Hereby it is possible to ensure a symmetrical movement of the displaceable connections, and thereby a position of the bar arrangement in relation to each other. For example it is possible to align a movement of a bar arrangement at one side of the platform with the movement of a bar arrangement at the other side of the platform in a mirrored way in relation to an axis in a radial direction from the tower.

The bar arrangement consist of a pair of telescopic lattice beams, which can comprise outer beams and inner beams which outer beams are capable of being displaced in beam guides in a longitudinal direction of the outer beams and in relation to the platform.

Hereby it is possible to provide a platform for a blade access arrangement, which platform in a transport situation between wind power plants can be reduced in size in such a way the whole arrangement can be transported on a trailer or on other suitable vehicle.

The telescopic beams are provided at each side of the platform and can be extended or retracted synchronously at both sides of the platform.

Hereby it is possible to move the platform along an axis in a radial direction of the tower without turning the platform.

The telescopic beams are provided at each side of the platform and can be extended or retracted independently at each sides of the platform.

Hereby it is possible to turn or rotate the platform in relation to a vertical axis by moving the telescopic beams over a distance in opposite directions or by moving the telescopic beams over a distance with different velocity, or even by moving one beam at a time.

In an embodiment, the lattice beams are provided with a square or rectangular cross section.

In an alternative embodiment, the lattice beams are provided with a triangular or trapezoidal cross section.

Hereby it is possible to provide strong telescopic beams and at the same time keep the weight low.

In an embodiment the pivot points in which the bar arrangement is connected to the tower guide means are positioned in a fixed distance to each other.

Hereby the ends of the telescopic beams is in a fixed distance in relation to each other.

In an embodiment the pivot points in which the bar arrangement is connected to the tower guide means are positioned in a variable distance to each other by means of a length adjustable connection bar.

This will give a further possibility of changing the shape or configuration of the platform in relation to a cross section of the blade.

Effects and features of the different embodiments are to a large extent analogous to those described above in connection with the first embodiment.

The present disclosure will become apparent from the detailed description given below. The detailed description and specific examples disclose preferred embodiments of the disclosure by way of illustration only. Those skilled in the art understand from guidance in the detailed description that changes and modifications may be made within the scope defined by the appended claims.

<FIG> shows a blade access arrangement <NUM> for a rotor blade <NUM> of a wind power plant <NUM>. The wind power plant <NUM> has a tower <NUM>. A nacelle <NUM> is arranged on top of the tower <NUM>. The blade <NUM> is fixed to a hub of a rotor which is rotatably supported in the nacelle <NUM>, the rotor comprising a number of blades <NUM>.

The blade access arrangement <NUM> comprises a platform <NUM>, The platform <NUM> has sides extending from a front end to a back end of the platform <NUM> and is connected to tower guide means <NUM> which rest against the tower <NUM>. The tower guide means <NUM> can be provided with rollers <NUM> so that the tower guide means <NUM> can guide the platform <NUM> along the tower <NUM>. The tower guide means <NUM> are connected to the platform <NUM> by means of a bar arrangement <NUM>, <NUM>, which bar arrangement <NUM>, <NUM> connects the platform <NUM> with the tower guiding means <NUM> and a hoisting arrangement for hoisting the blade access arrangement <NUM> up and down. The hoisting arrangement comprises a pair of hoisting means <NUM>, <NUM> placed on each side <NUM>, <NUM> of the platform <NUM>. The hoisting arrangement <NUM>, <NUM> comprises a further hoisting means <NUM>, which is placed on a hoisting arm <NUM> at the back end of the platform <NUM> or placed on the back end of the platform <NUM>. The hoisting arm <NUM> can be connected pivotably to the back end of the platform <NUM>, the back end of the platform <NUM> being the end closest to the tower guide means <NUM>.

The platform <NUM> comprises four sub-platforms <NUM>, <NUM>, <NUM>, <NUM>, where the sub-platform <NUM> further can be divided into two sub-platform parts for easy access of a wind turbine blade <NUM> into the center of the platform <NUM> by opening the platform <NUM> for encircling the blade <NUM>.

The sub-platforms <NUM>, <NUM>, <NUM>, <NUM> are connected by a plurality of spaced apart slats or lamellae hinged to the sub-platforms <NUM>, <NUM>, <NUM>, <NUM> forming a decking <NUM>. The number of slats in the decking <NUM> is adapted so that openings between slats are kept at a minimum preventing items to fall from the platform <NUM> when the platform <NUM> changes its shape or configuration during use.

When the platform <NUM> is in closed position an opening is provided in centre of the platform <NUM> through which opening a wind turbine blade <NUM> can extend.

Changing shape or configuration of the platform <NUM> can be done by use of actuators or like equipment positioned between sub-platforms <NUM>, <NUM>, <NUM>, <NUM> or between sub-platforms <NUM>, <NUM>, <NUM>, <NUM> and frames for the decking <NUM>.

Hereby it is possible to follow the shape of the cross section of the blade <NUM>.

An advantageous form or shape of each sub-platform <NUM>, <NUM>, <NUM>, <NUM> can be a trapezoid.

The tower guide means <NUM> is arranged in pairs in a distance from each other and configured to be distributed along a perimeter of the tower, for example as shown in <FIG>. Here the tower guide means <NUM> comprises a connection element <NUM> spacing the tower guide means <NUM> apart. Each of the tower guide means is provided with a pivot point <NUM>, <NUM> to which a bar of the bar arrangement in shape of telescopic lattice beams <NUM>, <NUM> is connected in a joint in such a way that the joint can pivot around an axis perpendicular to a plane parallel to a floor section of the platform <NUM>.

The telescopic lattice beams <NUM>, <NUM> comprises outer beams <NUM>, <NUM> and inner beams <NUM>, <NUM> which inner beams is capable of being displaced inside and in a longitudinal direction of the outer beams <NUM>, <NUM> as indicated for example in <FIG>, <FIG> and <FIG>. The inner <NUM>, <NUM>, <NUM>, <NUM> and outer <NUM>, <NUM> beams are displaceable relative to each other in a lengthwise direction in order to perform a telescopic action. The outer and inner beams can be moved relative to each other by hydraulic or pneumatic cylinders, but since weight is an important factor other solutions such as a wire or belt drive in combination with a number of pulleys and one or more motors driving a pulley, wheel or capstan (not shown), can be suitable solutions.

Also the beams <NUM>, <NUM> being lattice beams reduces the overall weight of the blade access arrangement <NUM>. The beams <NUM>, <NUM> can have a square or rectangular cross section.

In an alternative embodiment (not shown), the lattice beams <NUM>, <NUM> can have a triangular or trapezoidal cross section.

A number of wheels, rollers or bushings (not shown) can be provided between the inner <NUM>, <NUM>, <NUM>, <NUM> and outer <NUM>, <NUM> beams in order to facilitate relative movement between the beams.

Between the platform <NUM> and the telescopic beams <NUM>, <NUM> one or more pair of beam guides <NUM>, <NUM> are provided. The beam guides <NUM>, <NUM> allows the beams <NUM>, <NUM> to be displaced in a crosswise direction in relation to a longitudinal direction of the beams <NUM>, <NUM>. One pair of beam guides <NUM> are provided at the sub-platform <NUM> end of the platform <NUM> pointing towards the tower <NUM> and a beam guide <NUM> is provided at each of the sub-platforms <NUM>, <NUM> forming a middle part of the platform <NUM>. The beam guides <NUM>, <NUM> are also provided with wheels or rollers <NUM> to facilitate relative movement between the outer beams <NUM>, <NUM> and the beam guides <NUM>, <NUM> in a lengthwise direction in relation to the beams and in relation to the platform <NUM>.

The beam guides <NUM> at the sub-platforms <NUM>, <NUM> is connected to the sub-platforms <NUM>, <NUM> each via a pivot point <NUM>, <NUM>.

When the platform <NUM> changes shape as shown in <FIG>, <FIG> and <FIG>, <FIG> by moving two or more of the sub-platforms <NUM>, <NUM>, <NUM>, <NUM> relative to each other by actuating means, the pivot points <NUM>, <NUM> connecting the sub-platforms <NUM>, <NUM> with the beam guides <NUM>, a distance between the pivot points <NUM>, <NUM> will change. A distance between the pivot points <NUM>, <NUM> shown in <FIG>, <FIG> connecting the telescopic beams <NUM>, <NUM> with the tower guide <NUM> will remain the same.

The beam guide <NUM> in the end of the platform <NUM> closest to the tower guide means <NUM> is constructed as displaceable connections 40a, 40b or sliding arms having a slidable connection to the platform, shown for example in <FIG>, <FIG>, <FIG> and <FIG>. When the platform changes shape or configuration, the sliding arms 40a, 40b will slide in a crosswise direction in relation to the lengthwise direction of the telescopic beams <NUM>, <NUM>. The sliding arms 40a, 40b is connected to each other by a drivetrain.

In an embodiment, as indicated in <FIG>, the drivetrain comprises a flexible member <NUM> being flexible around its longitudinal axis and a pulley <NUM>. The flexible member <NUM> can be a wire a belt or another bendable element without substantial longitudinal elasticity.

The flexible member <NUM> is connected to ends of the sliding arms 40a, 40b pointing towards each other. When the flexible member <NUM> is led over the pulley <NUM> having an axis substantially perpendicular to the flexible member the result is that when one sliding arm 40a is moved away from a center line through the platform <NUM> running along and between the telescopic beams <NUM>,<NUM> the opposite sliding arm 40b will be forced to move in the opposite direction.

Between the sliding arms 40a, 40b can be provided a return spring (not shown) to bring the sliding arms 40a, 40b into a closer position when tension of the flexible member becomes smaller due to one of the arms 40a, 40b moving towards the center line again.

Hereby is obtained a symmetric movement of the sliding arms causing a movement of the beams <NUM>, <NUM> from a parallel position to a more open angle position, where free ends of the beams <NUM>, <NUM> or extension beams <NUM>, <NUM> achieves a greater distance between each other compared to the distance between the ends of the beams <NUM>, <NUM> connected to the pivot points <NUM>, <NUM>.

Thereby the wire system <NUM> provides that movement of one telescopic beam <NUM> in relation to the platform <NUM>, more precisely in relation to sub-platform <NUM>, will be mirrored in the other telescopic beam <NUM> and vice versa.

Movement can be initiated by movement of the sub-platforms relative to each other.

In an embodiment the bars <NUM>, <NUM> can be angular displaced in relation to each other whereby the platform <NUM> changes its configuration from square-shaped or rectangular to another shape. Examples is shown in <FIG> and <FIG>.

In an embodiment, the drivetrain between the sliding arms 40a, 40b can be disabled. Hereby it is possible to turn the platform <NUM> around a wind turbine blade <NUM> going through the center opening of the platform <NUM> by extending one side of the telescopic beams at a time, moving the telescopic beams in opposite directions or by moving the telescopic beams with different speed or velocity (moving one beam <NUM> on one side of the platform <NUM> slower than the beam <NUM> at the other side of the platform <NUM> or vice versa).

In an embodiment, the connection element <NUM> can be adjustable in length to be able to further adjust the shape or configuration of the platform <NUM>.

Claim 1:
Blade access arrangement (<NUM>) for a rotor blade (<NUM>) of a wind power plant (<NUM>) having a tower (<NUM>), the arrangement (<NUM>) comprising a platform (<NUM>) having a number of sub-platforms (<NUM>, <NUM>, <NUM>, <NUM>) movably connected to each other by means of a connecting arrangement, tower guide means (<NUM>) arranged in pairs in a distance from each other and configured to be distributed along a perimeter of the tower (<NUM>) for guiding the platform (<NUM>) against the tower (<NUM>), a bar arrangement (<NUM>, <NUM>) connecting the platform (<NUM>) with the tower guiding means (<NUM>) and a hoisting arrangement for hoisting the blade access arrangement (<NUM>) up and down, where each of the tower guide means (<NUM>) is provided with a pivot point (<NUM>, <NUM>),
characterized in that the bar arrangement (<NUM>,<NUM>) is provided at each side of the platform (<NUM>), and in that to the pivot point (<NUM>,<NUM>) a bar of the bar arrangement (<NUM>, <NUM>) in shape of telescopic lattice beams (<NUM>, <NUM>) is at an end connected to the tower guide means (<NUM>) in a joint (<NUM>, <NUM>) in such a way that the joint can pivot around an axis perpendicular to a plane parallel to a floor section of the platform (<NUM>), and in that in a distance from the end of the bar arrangement (<NUM>, <NUM>), the bar arrangement (<NUM>,<NUM>) at each side of the platform (<NUM>) is connected to a sub-platform (<NUM>, <NUM>) of the platform (<NUM>) by a further pivot point (<NUM>, <NUM>) and that the bar arrangement (<NUM>, <NUM>) at each side of the platform (<NUM>), is connected to another sub-platform (<NUM>) by a pair of displaceable connections (40a, 40b) capable of being displaced in a direction crosswise to a lengthwise direction of the bar arrangement (<NUM>, <NUM>).