WO2021013314A1

WO2021013314A1 - Wind turbine nacelle hatch assembly

Info

Publication number: WO2021013314A1
Application number: PCT/DK2020/050208
Authority: WO
Inventors: Maja Rose Wieland; Henrik Jakobsen
Original assignee: Vestas Wind Systems A/S
Priority date: 2019-07-24
Filing date: 2020-07-08
Publication date: 2021-01-28

Abstract

A wind turbine nacelle hatch assembly (40) includes a frame (44) including first and second rails (46, 48) extending in a longitudinal direction between proximal and distal rail ends (50, 52), and fixed against movement relative to and spaced apart from each other to define an aperture (30). The assembly (40) also includes a chassis (70) extending between proximal and distal chassis ends (80, 82), wherein the chassis (70) is pivotably coupled to the frame (44) near the proximal chassis end (80). The assembly (40) includes a hatch (42) extending between proximal and distal hatch ends (140, 142). The hatch (42) is pivotably coupled to the chassis (70) near the distal chassis end (82) and between the proximal and distal hatch ends (140, 142). The hatch (42) is pivotably and translatably supported by the first and second rails (46, 48) near the distal hatch end (142), such that the hatch (42) is movable between a closed position wherein the hatch (42) substantially covers the aperture (30) and an open position wherein the hatch (42) is transverse to the longitudinal direction.

Description

WIND TURBINE NACELLE HATCH ASSEMBLY

Technical Field

[0001] This invention generally relates to wind turbines, and more particularly to a hatch assembly for a wind turbine nacelle.

Background

[0002] Wind turbines are used to produce electrical energy using a renewable resource and without combusting a fossil fuel. Generally, a wind turbine converts kinetic energy from the wind into electrical power. A

horizontal-axis wind turbine includes a tower, a nacelle located at the apex of the tower, and a rotor having a plurality of blades extending from a hub and supported in the nacelle by means of a shaft. The shaft couples the rotor either directly or indirectly with a generator, which is housed inside the nacelle.

Consequently, as wind forces the blades to rotate, electrical energy is produced by the generator.

[0003] The nacelle houses various components that convert the mechanical energy from the rotor into electrical energy. For example, the nacelle generally includes a drive train and an electrical generator that collectively facilitate the production of electrical energy. More particularly, the drive train transforms the mechanical energy of the rotor into a suitable input for the electrical generator. In this regard, the drive train may include a gearbox that transforms the generally low angular velocity main shaft into a higher angular velocity secondary shaft. The secondary shaft is, in turn, operatively coupled to the electrical generator for rotating the generator rotor relative to the stator so as to produce electrical energy. The nacelle also includes various components that provide for the efficient operation of the wind turbine (e.g., pitch mechanism, yaw mechanism, brake mechanism, etc.). As such, the nacelle operates as a housing for many of the primary internal components that result in the efficient operation of the wind turbine.

[0004] A conventional nacelle includes at least a ceiling, a plurality of external sidewalls, a floor for supporting equipment and personnel thereon, and a subfloor positioned below the floor. A nacelle may also include at least one internal wall for separating a high voltage area, such as a transformer room, from the remaining interior of the nacelle. In any event, the floor may be spaced above the subfloor by between approximately 0.5 m and approximately 1 m, for example. Typically, a generally rectangular aperture is provided in the floor of the nacelle, and a hatch selectively covers the aperture in the floor. For example, such a hatch may be full-sized to cover the entire aperture and may be hingedly coupled to the floor of the nacelle at or near a peripheral side of the aperture such that the hatch may be rotatable between an open position (uncovering the aperture and extending into the interior of the nacelle) and a closed position (covering the aperture and generally flush with the floor).

Typically, a corresponding aperture is provided in the subfloor of the nacelle and aligned with the aperture in the floor, and another hatch selectively covers the aperture in the subfloor. For example, such a hatch may be a“split-hatch” including two panels hingedly coupled to the subfloor of the nacelle at or near opposite peripheral sides of the aperture.

[0005] During initial installation or during repair, replacement, and/or other maintenance operations, there may be a need to access the interior of the nacelle. By way of example, there may be a need to transport various items to the interior of the nacelle. This may include, for example, original components, replacement components, spare parts, service tools, and equipment. These items may typically weigh between 50 kg and 100 kg, but may weigh as much as or exceed 1 ton, for example. There may also be a need to transport such items out of the interior of the nacelle at the beginning or end of an install or repair operation. For example, if a component is broken then the initial steps of the repair operation may include removing the component from the interior of the nacelle. Conventionally, the transportation of such items to or from the interior of the nacelle is achieved via an internal lift system such as a crane positioned in the interior of the nacelle above the apertures in the floor and subfloor of the nacelle. When the hatches are rotated to the respective open positions, payloads including the desired items may be hoisted into or out of the interior of the nacelle through the uncovered apertures via the crane.

[0006] It is well-known that an uncovered aperture in the floor of the nacelle can present hazardous conditions for personnel and equipment both within the interior of the nacelle, such as a risk of accidentally falling into the uncovered aperture, and on the ground below the nacelle, such as a risk of being struck by accidental overhead falling objects. In many cases, the layout of the nacelle only allows access to one side of the aperture in the floor. A personal fall restraint system and/or a guard rail is required for preventing personnel or equipment from inadvertently falling from the interior of the nacelle into the uncovered aperture. Permanent guard rails are typically undesirable since such guard rails would require an increased vertical height of the nacelle to allow sufficient clearance for hoisting payloads thereover. Temporary or portable guard rails are typically preferred, but these must be manually installed by personnel for each use and can therefore be subject to misuse or even non use when the aperture is uncovered. In some cases, the hatch is hingedly coupled to the floor at the exposed side of the aperture so that, when the hatch is rotated to the open position, the hatch itself may provide a barrier for preventing personnel or equipment from inadvertently falling from the interior of the nacelle into the uncovered aperture.

[0007] However, it is also well-known that space is significantly limited in the interior of the nacelle, particularly when a payload is suspended above the aperture. The spatial constraints within the interior of the nacelle are

exacerbated when the hatch is hingedly coupled to the floor as described above, since such hatches have an undesirably large operating envelope or sweep when the hatch moves between the open and closed positions as the hatch must swing outwardly with its proximal end fixed at the hinged connection and its distal end traveling along an arc-shaped path having a radius equal to the entire length of the hatch. As a result, a suspended payload may undesirably interfere with the opening and closing of the hatch. For example, the hatch may collide with such a suspended payload during rotation between the open and closed positions. In this regard, if an incoming payload is raised into the interior of the nacelle and suspended above the aperture with the hatch in the open position, horizontal movement of or access to the suspended payload may be inhibited by the open hatch and surrounding components. Likewise, if an outgoing payload is suspended above the aperture with the hatch in the closed position, opening of the hatch may be inhibited by the suspended payload. Thus, the spatial constraints within the interior of the nacelle may render some hoisting operations difficult or impossible. At a minimum, such hoisting operations may require tedious and time-consuming manipulation of the payload and/or hatch by personnel to achieve the desired result. [0008] In an effort to address some of the concerns described above, split-hatch designs have been used to selectively cover the aperture in the floor of the nacelle. Such designs typically include two panels hingedly coupled to the floor of the nacelle at or near opposite peripheral sides of the aperture. For example, one panel may be hingedly coupled to the floor at the exposed side of the aperture and the other panel may be hingedly coupled to the floor at the opposite side of the aperture. Each panel may be approximately half of the size of the aperture, and thus approximately half of the size of a conventional full- sized hatch. As a result, a suspended payload may be less likely to interfere with the opening and closing of the panels than with a full-sized hatch.

Nevertheless, the open panels may still limit the lifting height of the payload and some interference can still occur. Moreover, the reduced size of such panels may prevent the panel located at the exposed side of the aperture from providing a sufficiently tall barrier when in the open position to prevent personnel or equipment from inadvertently falling from the interior of the nacelle into the uncovered aperture.

[0009] Manufacturers of wind turbines and wind turbine components continually strive to improve systems and methods associated with safely facilitating the transfer of service tools, equipment, and various wind turbine components into and out of the nacelle. It would therefore be desirable to provide an improved nacelle hatch assembly wherein the hatch provides a sufficiently tall barrier when in the open position to prevent personnel or equipment from inadvertently falling into the uncovered aperture and which allows personnel to perform hoisting operations with increased efficiency.

Summary

[0010] In one embodiment, a wind turbine nacelle hatch assembly includes a frame including first and second rails extending in a longitudinal direction between proximal and distal rail ends, and fixed against movement relative to and spaced apart from each other to at least partially define an aperture. The assembly also includes a chassis extending between proximal and distal chassis ends, wherein the chassis is pivotably coupled to the frame near the proximal chassis end. The assembly further includes a hatch extending between proximal and distal hatch ends, wherein the hatch is pivotably coupled to the chassis near the distal chassis end and between the proximal and distal hatch ends, and wherein the hatch is pivotably and translatably supported by the first and second rails near the distal hatch end, such that the hatch is movable between a closed position wherein the hatch substantially covers the aperture and an open position wherein the hatch is transverse to the longitudinal direction. In one embodiment, the distal end of the hatch is configured to move along a linear path when the hatch moves between the open and closed positions. For example, the hatch may further include first and second guides near the distal hatch end and extending laterally outwardly therefrom into engagement with the first and second rails,

respectively, and the first and second guides may be configured to translate along the first and second rails, respectively, in the longitudinal direction. In one embodiment, the first and second guides collectively define a movable rotational axis, and the first and second guides are configured to translate along the first and second rails, respectively, with the movable rotational axis in response to the hatch pivoting about the movable rotational axis. In addition or alternatively, at least one of the first and second guides may include a roller.

The first and second rails may each include an upper flange and a lower flange extending in the longitudinal direction and spaced apart from each other for capturing the respective one of the first and second guides therebetween. The upper flanges may include notches, and the first and second guides may be configured to pass through the respective notch for removing the hatch from the frame.

[0011] In one embodiment, the assembly further includes at least one lift support including a cylinder and a piston rod extendable from and retractable into the cylinder, wherein one of the cylinder or the piston rod is pivotably coupled to the frame and wherein the other of the cylinder or the piston rod is pivotably coupled to the chassis between the proximal and distal chassis ends. In addition or alternatively, the chassis may include at least one bumper configured to engage a bottom surface of the hatch when the hatch is in the open position to limit movement of the hatch. In one embodiment, the assembly further includes a lock configured to selectively fix at least one of the hatch and the chassis against movement relative to the frame when the hatch is in at least one of the open and closed positions.

[0012] In one embodiment, the hatch includes a slot extending from the distal hatch end toward the proximal hatch end and configured to receive a lifting cable or chain during a hoisting operation. In addition or alternatively, the hatch may be removably pivotably coupled to the chassis near the distal chassis end and between the proximal and distal hatch ends. In another embodiment, a wind turbine nacelle includes the wind turbine nacelle hatch assembly.

[0013] In another embodiment, a method of hoisting a payload into a wind turbine nacelle is provided. The method includes moving a hatch from a closed position wherein the hatch covers an aperture provided in the nacelle to an open position wherein the hatch at least partially uncovers the aperture and extends into an interior of the nacelle. The method also includes lifting the payload through the aperture, suspending the payload above the aperture and adjacent to the hatch, moving the hatch from the open position to the closed position, and accessing the payload from the interior of the nacelle. Moving the hatch from the closed position to the open position and moving the hatch from the open position to the closed position includes translating a distal end of the hatch along a linear path.

[0014] In another embodiment, a method of hoisting a payload out of a wind turbine nacelle is provided. The method includes suspending the payload above an aperture provided in the nacelle while a hatch is in a closed position wherein the hatch covers the aperture. The method also includes moving the hatch from the closed position to an open position wherein the hatch at least partially uncovers the aperture and extends into an interior of the nacelle adjacent the payload, and lowering the payload through the aperture. Moving the hatch from the closed position to the open position includes translating a distal end of the hatch along a linear path.

Brief Description of the Drawings

[0015] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with a general description of the invention given above, and the detailed description given below, serve to explain the invention.

[0016] FIG. 1 is a perspective view of an exemplary wind turbine in accordance with an aspect of the invention. [0017] FIG. 2 is a partial perspective view of the interior of the nacelle of the wind turbine shown in FIG. 1 , illustrating a wind turbine nacelle hatch assembly with the hatch thereof in a closed position.

[0018] FIG. 3 is a partial perspective view similar to FIG. 2, illustrating the hatch in an open position.

[0019] FIG. 4 is a partial disassembled view of the hatch assembly of FIG. 3, illustrating the chassis and a lift support of the hatch assembly each pivoted relative to the frame of the hatch assembly and illustrating the hatch pivoted relative to the chassis.

[0020] FIG. 5 is a cross sectional view of the hatch assembly of FIG. 3, illustrating intermediate positions of the hatch between the open and closed positions in phantom, and further illustrating a single-payload hoisting operation in phantom.

[0021] FIG. 5A is a cross sectional view similar to FIG. 5, illustrating a multi-payload hoisting operation in phantom.

[0022] FIG. 6 is a magnified view of the hatch assembly of FIG. 3, illustrating the auxiliary guard in a deployed position.

[0023] FIG. 7 is a magnified view of the hatch assembly of FIG. 3, illustrating the removal of a pivot pin to facilitate removal of the hatch from the frame.

[0024] FIG. 8 is a magnified view of the hatch assembly of FIG. 3, illustrating removal of the hatch from the frame.

Detailed Description

[0025] With reference to FIG. 1 , a wind turbine 10 includes a tower 12, a nacelle 14 disposed at the apex of the tower 12, and a rotor 16 operatively coupled to a generator (not shown) housed inside the nacelle 14. In addition to the generator, the nacelle 14 houses miscellaneous components required for converting wind energy into electrical energy and various components needed to operate, control, and optimize the performance of the wind turbine 10. The tower 12 supports the load presented by the nacelle 14, the rotor 16, and other components of the wind turbine 10 that are housed inside the nacelle 14 and also operates to elevate the nacelle 14 and rotor 16 to a height above ground level or sea level, as may be the case, at which faster moving air currents of lower turbulence are typically found. [0026] The rotor 16 of the wind turbine 10, which is represented as a horizontal-axis wind turbine, serves as the prime mover for the

electromechanical system. Wind exceeding a minimum level will activate the rotor 16 and cause rotation in a plane substantially perpendicular to the wind direction. The rotor 16 of the wind turbine 10 includes a central rotor hub 18 and a plurality of blades 20 that project outwardly from the central hub 18 at locations circumferentially distributed thereabout in equal intervals. In the representative embodiment, the rotor 16 includes three blades 20, but the number may vary. The blades 20 are configured to interact with the passing air flow to produce lift that causes the rotor hub 18 to spin about a longitudinal axis defined thereby. As shown, the tower 12 includes a foundation or base 22 for supporting the wind turbine 10 on a surface, such as a platform or the ground 24.

[0027] The wind turbine 10 may be included among a collection of similar wind turbines belonging to a wind farm or wind park that serves as a power generating plant connected by transmission lines with a power grid, such as a three-phase alternating current (AC) power grid. The power grid generally consists of a network of power stations, transmission circuits, and substations coupled by a network of transmission lines that transmit the power to loads in the form of end users and other customers of electrical utilities. Under normal circumstances, the electrical power is supplied from the generator to the power grid as known to a person having ordinary skill in the art.

[0028] With reference to FIGS. 2 and 3, the nacelle 14 of the wind turbine 10 includes a floor 26 and at least one internal wall 28. The floor 26 may be integrally formed or may be modular, such as by comprising a plurality of floor panels coupled together. In any event, a generally rectangular aperture 30 (FIG. 3) is provided in the floor 26 for allowing the transport of various items to and from the interior of the nacelle 14 such as original components,

replacement components, spare parts, service tools, and equipment via an internal lift system such as a crane positioned in the interior of the nacelle 14 above the aperture 30 so that payloads including the desired items may be hoisted into or out of the interior of the nacelle 14 through the aperture 30 via the crane. In one embodiment, the aperture 30 may have a width of between approximately 0.5 m and approximately 1.5 m, and may have a length of between approximately 0.5 m and approximately 1 m. For example, the aperture 30 may have a width of approximately 1.2 m and a length of

approximately 0.8 m. However, the aperture 30 may be of any suitable size and shape to accommodate the desired hoisting operations. In the embodiment shown, one side of the aperture 30 is generally adjacent to the internal wall 28. In addition or alternatively, various other components housed in the nacelle 14 such as electrical cabinets (not shown) may be adjacent one or more sides of the aperture 30.

[0029] In accordance with an aspect of the invention, the nacelle 14 of the wind turbine 10 includes an exemplary wind turbine nacelle hatch assembly 40. In the embodiment shown, the hatch assembly 40 includes a hatch 42 which is movable relative to the floor 26 of the nacelle 14 between a closed position wherein the hatch 42 covers the aperture 30 and at least a portion of the hatch 42 is generally flush with the floor 26 (FIG. 2) and an open position wherein the hatch 42 uncovers the aperture 30 and extends into the interior of the nacelle 14 (FIG. 3). As described in greater detail below, the hatch 42 provides a sufficiently tall barrier when in the open position to prevent personnel or equipment from inadvertently falling into the uncovered aperture 30, and the relatively small operating envelope or sweep of the hatch 42 when the hatch 42 moves between the open and closed positions allows personnel to perform hoisting operations with increased efficiency over the prior art.

[0030] The illustrated hatch assembly 40 includes a frame 44 fixed relative to the floor 26 of the nacelle 14. The frame 44 includes first and second rails 46, 48 extending in a longitudinal direction between proximal and distal rail ends 50, 52, and fixed against movement relative to and spaced apart from each other to at least partially define the aperture 30. Each rail 46, 48 includes an upper flange 54, a lower flange 56, and a side flange 58 extending

therebetween, such that each rail 46, 48 may have a generally C-shaped cross section and so that each upper flange 54 and lower flange 56 may reliably capture respective portions of the hatch 42 therebetween. The upper, lower, and side flanges 54, 56, 58 of each rail 46, 48 may be integrally formed together as one or more unitary pieces, or may be separately formed as distinct pieces and coupled together to form each rail 46, 48. In the embodiment shown, the first and second rails 46, 48 each include a notch 60 provided in the respective upper flange 54 for allowing the respective portions of the hatch 42 to pass therethrough, such as for selectively removing the hatch 42 from the frame 44, as described in greater detail below. As shown, the frame 44 also includes a laterally-extending proximal mount 61 (FIG. 4) for supporting various components of the hatch assembly 40 described below, and a laterally- extending distal ledge 62 for supporting at least a portion of the hatch 42 in the closed position.

[0031] As best shown in FIGS. 3 and 4, the hatch assembly 40 also includes a chassis 70 pivotably coupled to the frame 44. The illustrated chassis 70 includes first and second bars 72, 74 and a cross member 76 extending therebetween for rigidly coupling the first and second bars 72, 74 to each other. The chassis 70 and, more particularly, each of the first and second bars 72, 74, extends between proximal and distal chassis ends 80, 82, and the chassis 70 is pivotably coupled to the frame 44 at or near the proximal chassis end 80. In this regard, each of the first and second bars 72, 74 includes a proximal chassis bore 84 at or near the proximal chassis end 80, a distal chassis bore 86 at or near the distal chassis end 82, and an intermediate chassis bore 88 between the proximal and distal chassis ends 80, 82. In the embodiment shown, the chassis 70 includes distal bushings 90 at least partially defining the distal chassis bores 86. Each of the proximal, distal, and intermediate chassis bores 84, 86, 88 at least partially defines a respective pivot axis of the chassis 70 relative to other components of the hatch assembly 40 as described below. For example, the proximal chassis end 80 is pivotably coupled to the frame 44 to at least partially define a fixed pivot axis X1 of the chassis 70 relative to the frame 44. More particularly, the proximal chassis bores 84 are aligned with

corresponding bores 93 provided in brackets 94 fixed to the laterally-extending mount 61 of the frame 44, and respective pivot pins 96 extend therethrough such that the chassis 70 and the frame 44 are pivotably coupled to each other.

[0032] The illustrated chassis 70 also includes at least one bumper 98 configured to engage a portion of the hatch 42 when in the open position to limit movement of the hatch 42. The bumper 98 may be constructed of any suitable material such as rubber, for example, for avoiding damage to the hatch 42 and/or bumper 98 during such engagement. In the embodiment shown, the at least one bumper 98 is positioned on the cross member 76 proximate at least one of the first and second bars 72, 74. A lock 100 is configured to selectively fix the chassis 70 and/or hatch 42 against movement relative to the frame 44 when in the open and/or closed positions. The illustrated lock 100 includes a latch 102 (FIG. 7) pivotably coupled to a bracket 104 which is fixed to the cross member 76 of the chassis 70 and having a hook end 106 for mechanically engaging with a portion of the hatch 42 to selectively fix the hatch 42 against movement relative to the chassis 70 when in the open position and a pedal end 108 for allowing a user to manipulate the hook end 106 into or out of

engagement with the portion of the hatch 42, such as by using the user’s foot.

[0033] With continuing reference to FIGS. 3 and 4, first and second lift supports 1 10, 1 12 are provided between the frame 44 and the chassis 70 to assist a user in manipulating the chassis 70 and/or hatch 42. The exemplary lift supports 1 10, 1 12 are provided to operate as gas springs that push the hatch 42 upwards. In this regard, the lift supports 110, 1 12 each include a cylinder 1 14 and a piston rod 116 extendable from and retractable into the cylinder 1 14. As best shown in FIG. 4, each cylinder 1 14 includes a terminal end 120 having a proximal lift support bore 121 and each piston rod 1 16 includes an opposite terminal end 122 having a distal lift support bore 123. The terminal end 120 of each cylinder 114 is pivotably coupled to the frame 44 to at least partially define a fixed pivot axis X2 of the lift support 1 10, 112 relative to the frame 44, and the opposite terminal end 122 of the respective piston rod 1 16 is pivotably coupled to the chassis 70 between the proximal and distal chassis ends 80, 82 to at least partially define a movable pivot axis X3 of the lift support 110, 1 12 relative to the chassis 70. More particularly, the laterally-extending mount 61 of the frame 44 includes flanges 124 having bores 125 below the fixed pivot axis X1 of the chassis 70 relative to the frame 44 which are aligned with the proximal lift support bores 121 of the cylinders 1 14, and respective pivot pins 126 extend therethrough such that the lift supports 1 10, 112 and the frame 44 are pivotably coupled to each other. The relative positions of the pivot axes X1 , X2, X3 may be useful for providing the desired operation of the lift supports 1 10, 1 12.

[0034] Likewise, the distal lift support bores 123 of the piston rods 1 16 are aligned with the intermediate chassis bores 88 and respective pivot pins 128 extend therethrough such that the lift supports 1 10, 1 12 and the chassis 70 are pivotably coupled to each other. Alternatively, the terminal end 120 of each cylinder 1 14 may be pivotably coupled to the frame 44 and the terminal end 122 of each piston rod 1 16 may be pivotably coupled to the chassis 70 between the proximal and distal chassis ends 80, 82. In any event, each cylinder 1 14 may contain a gas which is capable of being compressed when the respective piston rod 1 16 is retracted into the cylinder 1 14, and which is capable of expanding to assist in extending the piston rod 1 16 from the cylinder 1 14. In another embodiment, one or both lift supports 110, 112 may be eliminated.

[0035] As best shown in FIGS. 2 and 3, the hatch 42 includes a generally rectangular panel 130 having a top surface 132 and a bottom surface 134 and extending between proximal and distal hatch ends 140, 142. The illustrated hatch 42 is configured to cover substantially the entire aperture 30, such that the hatch 42 may be considered to be full-size. In this regard, the top surface 132 may be configured to be generally flush with the floor 26 of the nacelle 14 when the hatch 42 is in the closed position to provide a generally even and continuous walking and/or support surface across substantially the entire area of the aperture 30. In one embodiment, the hatch 42 may have a width of between approximately 0.5 m and approximately 1.5 m, and may have a length of between approximately 0.5 m and approximately 1 m. For example, the hatch 42 may have a width of approximately 1.2 m and a length of

approximately 0.8 m. A pair of handholds 144 are provided in the panel 130 at or near the proximal hatch end 140, and a slot 146 extends inwardly from the distal hatch end 142 toward the proximal hatch end 140, the purposes of which are described below. A receiving portion in the form of an eyelet 148 is provided on the bottom surface 134 of the panel 130 for selectively receiving the hook end 106 of the latch 102 when the hatch 42 is in the open position, for example. In the embodiment shown, the panel 130 includes a proximal rim 150, a distal rim 152 (FIG. 4), and first and second side rims 154, 156 at or near the periphery of the panel 130. At least one lateral brace 158 extends between the first and second side rims 154, 156, and a pair of supplementary braces 159 flank the slot 146 to assist in providing rigidity to the hatch 42.

[0036] The hatch 42 is pivotably coupled to the chassis 70 at or near the distal chassis end 82 and between the proximal and distal hatch ends 140, 142, and the hatch 42 is pivotably and translatably supported by the lower flanges 56 of the first and second rails 46, 48 at or near the distal hatch end 142. In this regard, and as best shown in FIG. 4, each of the first and second side rims 154, 156 includes a proximal hatch bore 160 between the proximal and distal hatch ends 140, 142, and a distal hatch bore 162 at or near the distal hatch end 142. The proximal hatch bores 160 at least partially define a movable pivot axis X4 of the hatch 42 relative to the chassis 70. More particularly, the proximal hatch bores 160 are aligned with the distal chassis bores 86 and accompanying bushings 90, and respective pivot pins 164 extend therethrough such that the hatch 42 and the chassis 70 are pivotably coupled to each other. In the embodiment shown, each pivot pin 164 includes a bore 166 for receiving a respective spring pin 168 (FIG. 7) to selectively secure the pivot pin 164 within the proximal hatch bore 160, distal chassis bore 86, and accompanying bushing 90. In this manner, the hatch 42 may be removably pivotably coupled to the chassis 70 proximate the distal chassis end 82 and between the proximal and distal hatch ends 140, 142 as described below.

[0037] The illustrated hatch 42 further includes first and second guides in the form of rollers 170, 172 at or near the distal hatch end 142 and extending laterally outwardly from the first and second side rims 154, 156, respectively, and into engagement with the first and second rails 46, 48, respectively. The rails 46, 48 and rollers 170, 172 collectively define a guiding system for guiding movement of the distal hatch end 142. In this regard, the first and second rollers 170, 172 are aligned with the distal hatch bores 162, and respective axles 174 extend therethrough, such that the first and second rollers 170, 172 are configured to translate along the first and second rails 46, 48, respectively, between the proximal and distal rail ends 50, 52 thereof in the longitudinal direction. The illustrated first and second rollers 170, 172 are captured between the respective upper and lower flanges 54, 56 of the rails 46, 48 to assist in guiding movement of the rollers 170, 172 along the respective rails 46, 48. The axles 174 of the first and second rollers 170, 172 also collectively define a movable rotational axis X5 of the hatch 42 relative to the translation path of the rollers 170, 172. In this regard, the first and second rollers 170, 172 are configured to translate along the first and second rails 46, 48, respectively, in response to the hatch 42 pivoting about the rotational axis X5, thereby resulting in a corresponding translation of the movable rotational axis X5 of the hatch 42 defined by the rollers 170, 172. The rollers 170, 172 may be constructed of any suitable material such as plastic, for example, for minimizing friction between the rollers 170, 172 and the respective rails 46, 48.

[0038] In the embodiment shown, an auxiliary guard 180 is pivotably coupled to the hatch 42 such that the auxiliary guard 180 is movable between a stowed position wherein the auxiliary guard 180 substantially confronts the hatch 42 within a footprint thereof (FIG. 3) and a deployed position wherein the auxiliary guard 180 extends laterally away from a side of the hatch 42 (FIG. 6). The illustrated auxiliary guard 180 includes first and second brackets 182, 184 for receiving first and second hinge pins 186, 188 fixedly coupled to the bottom surface 134 of the panel 130 via respective third and fourth brackets 190, 192. As shown, the first bracket 182 includes a stop wall 194 configured to engage a portion of the hatch 42, such as the second side rim 156 thereof, when in the deployed position to limit movement of the auxiliary guard 180. An auxiliary guard lock 196 is configured to selectively fix the auxiliary guard 180 against movement relative to the hatch 42 when in the stowed and/or deployed position(s). The illustrated auxiliary guard lock 196 includes a plunger 198 extendably and retractably coupled to the third bracket 190 and having an end for receipt within one or more bores (not shown) in the first bracket 182 of the auxiliary guard 180 to selectively fix the auxiliary guard 180 against movement relative to the hatch 42. For example, the first bracket 182 of the auxiliary guard 180 may include a first bore which aligns with the plunger 198 when the auxiliary guard 180 is in the stowed position, such that receipt of the end of the plunger 198 in the first bore may selectively lock the auxiliary guard 180 in the stowed position, and/or the first bracket 182 of the auxiliary guard 180 may include a second bore which aligns with the plunger 198 when the auxiliary guard 180 is in the deployed position, such that receipt of the end of the plunger 198 in the second bore may selectively lock the auxiliary guard 180 in the deployed position. The plunger 198 may be biased, such as by a spring (not shown), to urge the end of the plunger 198 into one or both of such bores when aligned therewith. The auxiliary guard 180 may be sized to extend from a side of the hatch 42 substantially to the internal wall 28 of the nacelle 14 to inhibit personnel from passing between the hatch 42 and the internal wall 28 when in the deployed position. In one embodiment, the auxiliary guard 180 may have a width W of between approximately 0.25 m and approximately 1 m. For example, the auxiliary guard 180 may have a width W of approximately 0.4 m.

[0039] Referring now primarily to FIG. 5, with continuing reference to FIGS. 2-4, the hatch 42 may be moved from the closed position to the open position to allow at least one payload 200 to be hoisted through the aperture 30 into or out of the interior of the nacelle 14 via an internal lift system such as a crane (not shown) and one or more lifting cables or chains 204 and

accompanying hook(s) 208. While a single-payload hoisting operation is shown including a single payload 200 hoisted by the crane via the chain 204 and accompanying hook 208, any suitable number of payloads may be hoisted through the aperture 30 into or out of the interior of the nacelle 14, such as in a multi-payload hoisting operation as described in greater detail below.

[0040] Initially, the hatch 42 may be in the closed position such that the hatch 42 covers the aperture 30 and at least the top surface 132 of the hatch 42 is generally flush with the floor 26. When the hatch 42 is in the closed position, the rollers 170, 172 are at or near the distal rail ends 52, the distal hatch end 142 may be at least partially supported on the ledge 62, and the piston rods 1 16 of the lift supports 110, 1 12 may be retracted within the respective cylinders 1 14 such that the gas contained therein may be compressed.

[0041] Subsequently, an upward force may be applied to the hatch 42 at or near the proximal hatch end 140, such as via the handholds 144, as indicated by the arrows A1 in FIG. 2. As a result of such an upward force, the proximal hatch end 140 may be lifted upwardly. The motional constraints imposed on the hatch 42 described above cause the upward lifting of the proximal hatch end 140 to be directed about the movable rotational axis X5 defined by the axles 174 of the rollers 170, 172, and further cause the rollers 170, 172 and the rotational axis X5 to translate along the rails 46, 48 in the longitudinal direction toward the proximal rail ends 50. As the hatch 42 begins to move away from the closed position, the gas within the cylinders 114 of the lift supports 110, 1 12 may be permitted to expand, thereby extending the piston rods 1 16 from the cylinders 1 14 to assist the user in continued opening of the hatch 42. In this regard, the extension of the piston rods 1 16 from the cylinders 1 14 may apply a generally upward force against the chassis 70 at the movable pivot axis X3, thereby urging the hatch 42 to continue pivoting upwardly about the movable rotational axis X5 and causing the rollers 170, 172 and rotational axis X5 to translate along the rails 46, 48 further toward the proximal rail ends 50.

[0042] As the hatch 42 reaches the open position, the rollers 170, 172 may approach the proximal rail ends 50 and the hatch 42 may be pivoted about the movable rotational axis X5 to a vertical or near-vertical orientation wherein the hatch 42 is transverse to the longitudinal direction in which the rails 46, 48 extend such that the hatch 42 may be angled relative to the longitudinal direction. In one embodiment, the hatch 42 may be pivoted to an orientation substantially perpendicular to the longitudinal direction. For example, the hatch 42 may be angled at between approximately 80° and approximately 100° relative to the longitudinal direction in the open position. In one embodiment, the hatch 42 may be angled at approximately 86° or approximately 92° relative to the longitudinal direction in the open position. When in the open position, the hatch 42 provides a sufficiently tall barrier to prevent personnel or equipment from inadvertently falling into the uncovered aperture 30 from the interior of the nacelle 14. For example, the vertical distance FI between the raised proximal hatch end 140 and the floor 26 of the nacelle 14 may be between approximately 0.8 m and approximately 1.5 m. For example, the vertical distance FI may be approximately 0.9 m. As shown, the chassis 70 and lift supports 1 10, 1 12 may be at least partially received between the side rims 154, 156 of the hatch 42 when in the open position to provide a compact arrangement.

[0043] In one embodiment, the at least one bumper 98 may engage a portion of the hatch 42, such as the bottom surface 134 of the panel 130, when the hatch 42 is in the open position to limit movement of the hatch 42 and, more particularly, to prevent the hatch 42 from moving about the movable rotational axis X5 beyond the open position. The lock 100 may be operated by the user to selectively fix the chassis 70 and/or hatch 42 against movement relative to the frame 44 when in the open position. For example, the hook end 106 of the latch 102 may be manipulated into engagement with a portion of the hatch 42, such as the eyelet 148, by applying the user’s foot against the pedal end 108 of the latch 102. The engagement of the hook end 106 of the latch 102 with the eyelet 148 may resist movement of the hatch 42 away from the chassis 70 and thus resist movement of the rollers 170, 172 toward the distal rail ends 52, thereby securing the hatch 42 in the open position.

[0044] With the hatch 42 secured in the open position, the payload 200 may be reliably hoisted through the aperture 30 into or out of the interior of the nacelle 14 via the chain 204 and accompanying hook 208 in a known manner, for example.

[0045] In order to return the hatch 42 to the closed position, the hook end 106 of the latch 102 may be manipulated out of engagement with the eyelet 148 and a downward force may be applied to the hatch 42 at or near the proximal hatch end 140 sufficient to overcome any threshold force imposed by the lift supports 1 10, 1 12. As a result of such a downward force, alone or in combination with an inherent gravitational force acting on the hatch 42 at or near the proximal hatch end 140, the proximal hatch end 140 may be lowered downwardly. Such lowering may occur gradually due to the lift supports 1 10, 1 12. The motional constraints imposed on the hatch 42 described above cause the downward lowering of the proximal hatch end 140 to be directed about the movable rotational axis X5 defined by the axles 174 of the rollers 170, 172, and further cause the rollers 170, 172 and the rotational axis X5 to translate along the rails 46, 48 in the longitudinal direction toward the distal rail ends 52. As the hatch 42 begins to move away from the open position, the piston rods 1 16 may be forced to retract within the respective cylinders 1 14, thereby compressing the gas within the cylinders 1 14.

[0046] As the hatch 42 reaches the closed position, the rollers 170, 172 may approach the distal rail ends 52 and the hatch 42 may be pivoted about the movable rotational axis X5 to a horizontal or near-horizontal orientation wherein the hatch 42 covers the aperture 30 and is at least partially supported by the ledge 62, and at least the top surface 132 of the hatch 42 is generally flush with the floor 26.

[0047] It will be appreciated that the operating envelope or sweep of the hatch 42 may be substantially reduced as compared to that of a conventional hinged hatch. In other words, the open position, closed position, and

intermediate positions of the hatch 42 between the open and closed positions may be collectively confined to a reduced area when viewed from the side shown in FIG. 5. For example, unlike conventional hinged hatches, the exemplary hatch 42 does not swing outwardly with the proximal hatch end 140 fixed at a peripheral side of the aperture 30 and the distal hatch end 142 traveling along an arc-shaped path having a radius equal to the entire length of the hatch 42 between the open and closed positions. Rather, both the proximal and distal hatch ends 140, 142 move cooperatively to maintain the entire hatch 42 in relatively close proximity to one side of the aperture 30 throughout movement between the open and closed positions. More particularly, the distal hatch end 142 is confined to a linear path within the same horizontal footprint occupied by the hatch 42 when in the closed position. Likewise, the proximal hatch end 140 is confined to a generally vertical path which may avoid intersecting the space above the aperture 30. As a result, the intermediate positions of the hatch 42 between the open and closed positions may be tightly confined close to one side of the aperture 30, as compared to conventional hinged hatches. The reduced operating envelope may enable hoisting a payload 200 of a relatively large size through the aperture 30 without requiring complete disassembly or removal of the hatch 42. The reduced operating envelope may also allow the hatch 42 to be moved between the open and closed positions while the payload 200 is suspended above the aperture 30, so that such a relatively large payload 200 may be accommodated in the interior of the nacelle 14 without requiring an increase in the height of the nacelle 14.

[0048] As shown in FIG. 5, when the hatch 42 is in the open position, the payload 200 may be hoisted through the uncovered aperture 30 into the interior of the nacelle 14 and may be subsequently suspended above the aperture 30 and adjacent to the open hatch 42.

[0049] While the payload 200 is suspended at the illustrated position, it may be desirable to access the payload 200 within the interior of the nacelle 14. However, doing so may be difficult while the hatch 42 is the open position, since the uncovered aperture 30 may prevent personnel from being able to stand immediately next to the payload 200, and/or since the payload 200 may be too heavy to lift off of the hook 208 in one piece. Thus, it may be desirable to move the hatch 42 to the closed position in order to access the payload 200 within the interior of the nacelle 14. Due to the reduced operating envelope or sweep of the hatch 42, the hatch 42 may be moved from the open position to the closed position in the manner described above without colliding with the payload 200.

In this regard, as the hatch 42 transitions from the open position toward the closed position, the hatch 42 is able to tilt around and below the payload 200, rather than swing toward and collide with the payload 200 as a conventional hinged hatch would. Thus, the suspended payload 200 may avoid interfering with the closing of the hatch 42. With the hatch 42 in the closed position, the payload 200 may be accessed within the interior of the nacelle 14 as desired. Subsequently, the hatch 42 may be returned to the open position for performing additional hoisting operations through the uncovered aperture 30 into or out of the interior of the nacelle 14, for example.

[0050] With continuing reference to FIG. 5, when the hatch 42 is in the closed position, the payload 200 may be suspended above the covered aperture 30. [0051] While the payload 200 is suspended at the illustrated position, it may be desirable to remove the payload 200 from the interior of the nacelle 14. Thus, it may be desirable to move the hatch 42 to the open position in order to allow hoisting the payload 200 out of the interior of the nacelle 14. Due to the reduced operating envelope or sweep of the hatch 42, the hatch 42 may be moved from the closed position to the open position in the manner described above without colliding with the payload 200. In this regard, as the hatch 42 transitions from the closed position toward the open position, the hatch 42 is able to tilt around and beside the payload 200, rather than swing toward and collide with the payload 200 as a conventional hinged hatch would. Thus, the suspended payload 200 may avoid interfering with the opening of the hatch 42. With the hatch 42 in the open position, the payload 200 may be hoisted out of the interior of the nacelle 14 as desired. Subsequently, the hatch 42 may be returned to the closed position for covering the aperture 30, for example.

[0052] Referring now to FIG. 5A, first, second, and third payloads 200a, 200b, 200c may be hoisted through the aperture 30 into or out of the interior of the nacelle 14 by the crane via the chain 204 and one or more accompanying hooks 208 in a multi-payload hoisting operation. Movement of the hatch 42 between the open and closed positions may be substantially similar to that described above with respect to FIG. 5.

[0053] As shown in FIG. 5A, when the hatch 42 is in the open position, first and second payloads 200a, 200b may be hoisted through the uncovered aperture 30 into the interior of the nacelle 14 and may be subsequently suspended above the aperture 30 and adjacent to the open hatch 42.

Meanwhile, a third payload 200c may be suspended below the aperture 30 and secured to the same chain 204 carrying the first and second payloads 200a, 200b.

[0054] While the payloads 200a, 200b, 200c are suspended at the illustrated positions, it may be desirable to access the first and second payloads 200a, 200b within the interior of the nacelle 14. Thus, the hatch 42 may be moved from the open position to the closed position in the manner described above without colliding with the first and second payloads 200a, 200b. As the hatch 42 moves to the closed position, a portion of the chain 204 above the third payload 200c may be received by the slot 146 in the hatch 42 to accommodate the suspension of the third payload 200c below the aperture 30 via the chain 204. Thus, the suspended third payload 200c may avoid interfering with the closing of the hatch 42. Subsequently, the hatch 42 may be returned to the open position for hoisting the third payload 200c through the uncovered aperture 30 into the interior of the nacelle 14, for example.

[0055] With continuing reference to FIG. 5A, when the hatch 42 is in the closed position, the first, second, and third payloads 200a, 200b, 200c may initially be within the interior of the nacelle 14.

[0056] While the payloads 200a, 200b, 200c are within the interior of the nacelle 14, it may be desirable to remove the payloads 200a, 200b, 200c from the interior of the nacelle 14. Thus, the third payload 200c may be secured to the chain 204, such as via the hook 208, and the hatch 42 may be moved to the open position to allow hoisting the third payload 200c through the uncovered aperture 30 out of the interior of the nacelle 14. Subsequently, it may be desirable to secure the first and second payloads 200a, 200b to the same chain 204 while the third payload 200c is suspended below the aperture 30, such as to perform a multi-payload hoisting operation. Thus, the hatch 42 may be returned to the closed position while the third payload 200c remains suspended below the aperture 30. As the hatch 42 moves to the closed position, a portion of the chain 204 above the third payload 200c may be received by the slot 146 in the hatch 42 to accommodate the suspension of the third payload 200c below the aperture 30 via the chain 204. With the hatch 42 in the closed position, personnel may safely secure the first and second payloads 200a, 200b to the chain 204 within the interior of the nacelle 14. The hatch 42 may then be returned to the open position to allow hoisting the first and second payloads 200a, 200b through the uncovered aperture 30 out of the interior of the nacelle 14.

[0057] Referring now to FIG. 6, when the hatch 42 is in the open position, it may be desirable to supplement the barrier provided by the hatch 42 adjacent the uncovered aperture 30. For example, there may be a small void between the hatch 42 and the internal wall 28 of the nacelle 14. Thus, in one

embodiment, the auxiliary guard 180 may be moved from the stowed position to the deployed position in order to close off such a void. Initially, the end of the plunger 198 may be manipulated out of a respective bore in the first bracket 182 of the auxiliary guard 180. Such manipulation may include overcoming a spring bias urging the end of the plunger 198 toward such a bore. With the auxiliary guard lock 196 disengaged, the auxiliary guard 180 may be moved from the stowed position to the deployed position, as indicated by the arrow A2, so that the auxiliary guard 180 may extend laterally away from the hatch 42 substantially to the internal wall 28 of the nacelle 14 to inhibit personnel from passing between the hatch 42 and the internal wall 28. The stop wall 194 may engage a portion of the hatch 42, such as the second side rim 156 thereof, when in the deployed position to limit movement of the auxiliary guard 180 and, more particularly, to prevent the auxiliary guard 180 from pivoting beyond the deployed position. The auxiliary guard lock 196 may be operated by the user to selectively fix the auxiliary guard 180 against movement relative to the hatch 42 when in the deployed position. For example, the end of the plunger 198 may be manipulated into a respective bore in the first bracket 182 of the auxiliary guard 180, or may be biased thereinto by a spring when aligned therewith.

[0058] Referring now to FIGS. 7 and 8, it may be desirable in certain circumstances to remove the hatch 42 from the chassis 70 and/or from the frame 44. For example, it may be desirable to remove the hatch 42 to accommodate hoisting an oversized payload or large component through the aperture 30, or during a personnel rescue situation to accommodate a stretcher. Thus, in one embodiment, the hatch 42 may be selectively removed from the chassis 70 and/or from the frame 44. In this regard, the spring pins 168 may be removed from the bores 166 in the respective pivot pins 164 to allow removal of the pivot pins 164 from the respective proximal hatch bores 160, distal chassis bores 86, and accompanying bushings 90, as indicated by the arrow A3 (FIG.

7). Removal of the spring pins 168 and pivot pins 164 may be performed with the hatch 42 in or near the open position to allow access thereto. The hook end 106 of the latch 102 may be manipulated out of engagement with the eyelet 148 to disengage the lock 100, as indicated by the arrow A4, thereby completely releasing the hatch 42 from the chassis 70, and the hatch 42 may be slid toward the distal rail ends 52 under the respective upper flanges 54 until the rollers 170, 172 reach the respective notches 60. With the rollers 170, 172 aligned with the respective notches 60, the hatch 42 may be lifted above the nacelle floor 26 such that the rollers 170, 172 pass through the notches 60, as indicated by the arrows A5, thereby releasing the hatch 42 from the frame 44. The hatch 42 may then be set aside while an oversized hoisting operation is performed through the uncovered aperture 30, for example, and may be subsequently returned to the frame 44 and chassis 70.

[0059] Thus, as set forth above, the hatch assembly 40 may allow the hatch 42 to provide a sufficiently tall barrier when in the open position to prevent personnel or equipment from inadvertently falling into the uncovered aperture 30, and the relatively small operating envelope or sweep of the hatch 42 when the hatch 42 moves between the open and closed positions allows personnel to perform hoisting operations with increased efficiency over the prior art

[0060] While the present invention has been illustrated by a description of various preferred embodiments and while these embodiments have been described in some detail, it is not the intention of the Applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. The various features of the invention may be used alone or in numerous

combinations depending on the needs and preferences of the user.

Claims

What is claimed is:

1. A wind turbine nacelle hatch assembly (40), comprising:

a frame (44) including first and second rails (46, 48) extending in a longitudinal direction between proximal and distal rail ends (50, 52), and fixed against movement relative to and spaced apart from each other to at least partially define an aperture (30);

a chassis (70) extending between proximal and distal chassis ends (80, 82), wherein the chassis (70) is pivotably coupled to the frame (44) near the proximal chassis end (80); and

a hatch (42) extending between proximal and distal hatch ends (140, 142), wherein the hatch (42) is pivotably coupled to the chassis (70) near the distal chassis end (82) and between the proximal and distal hatch ends (140, 142), and wherein the hatch (42) is pivotably and translatably supported by the first and second rails (46, 48) near the distal hatch end (142), such that the hatch (42) is movable between a closed position wherein the hatch (42) substantially covers the aperture (30) and an open position wherein the hatch (42) is transverse to the longitudinal direction.

2. The wind turbine nacelle hatch assembly (40) of claim 1 , wherein the distal hatch end (142) is configured to move along a linear path when the hatch (42) moves between the open and closed positions.

3. The wind turbine nacelle hatch assembly (40) of claim 2, wherein the hatch (42) further includes first and second guides (170, 172) near the distal hatch end (142) and extending laterally outwardly therefrom into engagement with the first and second rails (46, 48), respectively, and wherein the first and second guides (170, 172) are configured to translate along the first and second rails (46, 48), respectively, in the longitudinal direction.

4. The wind turbine nacelle hatch assembly (40) of claim 3, wherein the first and second guides (170, 172) collectively define a movable rotational axis (X5), and wherein the first and second guides (170, 172) are configured to translate along the first and second rails (46, 48), respectively, with the movable rotational axis (X5) in response to the hatch (42) pivoting about the movable rotational axis (X5).

5. The wind turbine nacelle hatch assembly (40) of claim 3, wherein at least one of the first and second guides (170, 172) includes a roller.

6. The wind turbine nacelle hatch assembly (40) of claim 3, wherein the first and second rails (46, 48) each include an upper flange (54) and a lower flange (56) extending in the longitudinal direction and spaced apart from each other for capturing the respective one of the first and second guides (170, 172) therebetween.

7. The wind turbine nacelle hatch assembly (40) of claim 6, wherein the upper flanges (54) each include at least one notch (60), and wherein the first and second guides (170, 172) are configured to pass through the respective at least one notch (60) for removing the hatch (42) from the frame (44).

8. The wind turbine nacelle hatch assembly (40) of claim 1 , further comprising:

at least one lift support (1 10, 1 12) including a cylinder (1 14) and a piston rod (1 16) extendable from and retractable into the cylinder (1 14), wherein one of the cylinder (1 14) or the piston rod (1 16) is pivotably coupled to the frame (44) and wherein the other of the cylinder (1 14) or the piston rod (1 16) is pivotably coupled to the chassis (70) between the proximal and distal chassis ends (80, 82).

9. The wind turbine nacelle hatch assembly (40) of claim 1 , wherein the chassis (70) includes at least one bumper (98) configured to engage a bottom surface (134) of the hatch (42) when the hatch (42) is in the open position to limit movement of the hatch (42).

10. The wind turbine nacelle hatch assembly (40) of claim 1 , further comprising: a lock (100) configured to selectively fix at least one of the hatch (42) and the chassis (70) against movement relative to the frame (44) when the hatch (42) is in at least one of the open and closed positions.

1 1. The wind turbine nacelle hatch assembly (40) of claim 1 , wherein the hatch (42) includes a slot (146) extending from the distal hatch end (142) toward the proximal hatch end (140) and configured to receive a lifting cable or chain (204) during a hoisting operation.

12. The wind turbine nacelle hatch assembly (40) of claim 1 , wherein the hatch (42) is removably pivotably coupled to the chassis (70) near the distal chassis end (82) and between the proximal and distal hatch ends (140, 142).

13. A wind turbine nacelle (14) including the wind turbine nacelle hatch assembly (40) of claim 1.

14. A method of hoisting a payload (200) into a wind turbine nacelle (14), the method comprising:

moving a hatch (42) from a closed position wherein the hatch (42) covers an aperture (30) provided in the nacelle (14) to an open position wherein the hatch (42) at least partially uncovers the aperture (30) and extends into an interior of the nacelle (14);

lifting the payload (200) through the aperture (30);

suspending the payload (200) above the aperture (30) and adjacent to the hatch (42);

moving the hatch (42) from the open position to the closed position; and accessing the payload (200) from the interior of the nacelle (14), wherein moving the hatch (42) from the closed position to the open position and moving the hatch (42) from the open position to the closed position each include translating a distal end (142) of the hatch (42) along a linear path.

15. A method of hoisting a payload (200) out of a wind turbine nacelle (14), the method comprising: suspending the payload (200) above an aperture (30) provided in the nacelle (14) while a hatch (42) is in a closed position wherein the hatch (42) covers the aperture (30);

moving the hatch (42) from the closed position to an open position wherein the hatch (42) at least partially uncovers the aperture (30) and extends into an interior of the nacelle (14) adjacent the payload (200); and

lowering the payload (200) through the aperture (30),

wherein moving the hatch (42) from the closed position to the open position includes translating a distal end (142) of the hatch (42) along a linear path.