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Patent Searching and Data


Title:
A LADDER APPARATUS FOR A SOLAR PANEL OR SOLAR ARRAY
Document Type and Number:
WIPO Patent Application WO/2018/229617
Kind Code:
A1
Abstract:
The present invention relates to a ladder apparatus for maintenance of a solar panel or array of solar panels. The ladder apparatus has a pair of substantially parallel rails joined by a plurality of rungs and an elongate sheet provided between the rungs and the solar panel. The rails are adapted to receive at least one sliding bracket. Each sliding bracket supports at least one hook that extends from the sliding bracket to permit engagement of the hook with part of a solar panel so as to locate the ladder on the solar panel. A locking means is provided to fix each sliding bracket in position on a rail.

Inventors:
COULING MICHAEL (GB)
COULING ERIC (GB)
Application Number:
IB2018/054158
Publication Date:
December 20, 2018
Filing Date:
June 08, 2018
Export Citation:
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Assignee:
RENEWECARE LTD (GB)
International Classes:
E06C1/34; E06C7/48
Foreign References:
FR2484520A11981-12-18
JP2016084637A2016-05-19
JP2001012076A2001-01-16
US20110247895A12011-10-13
DE19815236A11999-10-14
AU2014101465A42015-02-05
Attorney, Agent or Firm:
WALKER, Neville (Swanage Dorset BH19 1DF, GB)
Download PDF:
Claims:
Claims

A ladder apparatus for maintenance of a solar panel, comprising: a pair of substantially parallel rails joined by a plurality of rungs and an elongate sheet of material arranged in use below the rungs; the rails are adapted to receive at least one sliding bracket; each sliding bracket is associated with at least one hook that extends downwards from the rail to permit engagement of the hook with part of a solar panel so as to locate the ladder on the solar panel; and a locking means to fix each sliding bracket in position on a rail.

A ladder apparatus according to claim 1 wherein a pair of sliding brackets arranged on the pair of substantially parallel rails are adapted to receive an elongate member extending therebetween from which a pair of hooks suspend.

A ladder apparatus according to claim 2 wherein the hooks are supported by and suspended from a connector mounted on the elongate member.

A ladder apparatus according to any preceding claim wherein the substantially parallel rails comprise a metal extrusion.

A ladder apparatus according to any preceding claim wherein the hook is coated in a resiliently deformable material so as to protect the solar panel from damage.

A ladder apparatus according to claim 6 including an attachment means for receiving the elongate sheet of material.

A ladder apparatus according to claim 6 wherein the elongate sheet of material is formed from a synthetic plastics material.

A ladder apparatus according to any preceding claim where're in each rung includes a harness anchor for receiving a safety line.

9. A ladder apparatus according to any preceding claim including a handle provided at each end of the rails.

10. A ladder apparatus according to claim 9 wherein each handle is attached at a pivot and includes a means for locking movement of the handle with respect to the rails.

1 1 . A ladder apparatus according to any preceding claim including an anchor bracket arranged on the solar panel for receiving the hook.

12. A ladder apparatus according to any preceding claim wherein the rungs have a grip surface.

13. A ladder apparatus according to any preceding claim wherein the rungs include padding.

14. A ladder according to claim 13 wherein the padding extends over part of the rungs only.

15. A ladder apparatus according to any preceding claim including a GPS tracker.

16. A ladder apparatus according to any preceding claim including a trolley.

17. A ladder apparatus according to claim 16 including at least ground anchoring peg.

18. A method of deploying the ladder apparatus as defined by any of claims 1 to 15 including the steps of : sliding the sliding brackets to the desired location along the rails that corresponds to the dimensions of the solar panel and locking them in position; lifting the ladder on to the module to engage the hooks associated with the sliding brackets with the solar panel.

19. A method of deploying the ladder apparatus according to claim 16 comprising the steps of: placing the trolley on the solar array; securing the trolley to the ground; lifting the ladder onto the trolley; un-securing the trolley from the ground; rolling the trolley and ladder to a location adjacent to the position of use; securing the trolley to the ground; and lifting the ladder from the trolley and placing it onto the solar panel for use so that the hooks are in contact with the solar panel.

Description:
A LADDER APPARATUS FOR A SOLAR PANEL OR SOLAR ARRAY Field of the Invention The present invention relates to a ladder apparatus for use on a solar panel or array of solar panels; in particular apparatus for allowing access to install, maintain, clean and repair a solar panel or solar array; such as but not exclusively an array formed of multiple photovoltaic modules. Background

Increasing numbers of properties and users are using photovoltaic modules, cells or solar cells to supply electricity. Frequently the photovoltaic cells or solar cells are arranged in arrays of multiple modules or panels, all being tilted towards the sun at a fixed or an adjustable angle.

For a number of years there has been a problem when installing and maintaining solar panels as well as a need to clean and repair damaged modules. There has been no way to carry out this work without standing on the solar panels.

This maintenance has caused users high costs in replacing brand modules after construction often because of cracked glass. In most circumstances only hairline cracks were created by standing on the modules. In other cases modules have cracked completely and required replacement.

Prior Art

CN 204 960 775 (LU) discloses a climbing device for a photovoltaic module. CN 204 002 517 (LI et al) discloses an anti-slip ladder for mounting and maintaining components in a photovoltaic plant.

JP 2000 145 130 (KAWAKAMI) discloses a maintenance ladder for a roof equipped with a solar battery by which maintenance work was able to be efficiently carried out. US4483416 (Garcia) discloses a ladder including upstanding opposite side rails and vertically spaced rungs.

WO2014/194366 (O'Donnell) discloses a ladder safety mechanism with at least one clamp.

GB2026073 (Primerano) discloses adjustable ladder hooks with hooks pivotably mounted on carriers in turn slideable either along the ladders stiles or along a bracket.

FR2694783 (Sevrin) discloses a safety device for stopping ladders from overturning.

DE19755390 (Kofferath) discloses a holder in the form of a guide rail parallel with the ladder struts.

The present invention arose in order to overcome problems suffered by existing devices.

Summary of the Invention

According to the present invention there is provided ladder apparatus for use with a solar panel, comprising: a pair of substantially parallel rails joined by a plurality of rungs and an elongate sheet of material arranged in use below the rungs ; the rails are adapted to receive at least one sliding bracket; each sliding bracket is associated with at least one hook that extends downwards from the rail to permit engagement of the hook with part of the solar panel so as to locate the ladder on the solar panel; and a locking means fixes each sliding bracket in position on a rail.

The at least one hook provides a means of securely engaging the ladder with the solar panel or solar array. The hook serves to connect the ladder to the solar panel or solar array.

In this way the apparatus can be deployed so that it spans over one or more solar panels thereby permitting maintenance without causing damage to the module(s). Damage is also prevented by the sheet which acts as a 'safety net' for tools or cleaning devices sued by personnel as they traverse the solar panel. A solar panel includes at least one photovoltaic cell to absorb sunlight and generate electricity. The solar panel may include an integrated frame or may be mounted on a frame. It is therefore appreciated that the hook(s) may engage with various parts that make up the module. In this way the apparatus is suitable for use with different embodiments of solar panels.

Advantageously the ladder apparatus can be arranged for use with solar panel arrays so as to allow a user to gain access to a large solar panel which may comprise many panels or arrays without standing on glass in the panels or the arrays.

The apparatus includes a ladder that extends across an upper face of a solar panel so that a user is able to climb across the modules, safely reaching all areas for maintenance, cleaning and repair works. The apparatus is adapted to fit to the module such that the photovoltaic cells or solar cells and covering layers are protected whilst access over the entire upper surface of the module is permitted.

Typically the weight of the apparatus is borne by the frame upon which the solar panel is arranged. The ladder apparatus is adapted to engage with the frame so as to locate the apparatus on the module.

The ladder apparatus is easily fitted by means of the hooks that are provided on brackets which are shaped and dimensioned to fit over parts of the module which may include the frame.

It is appreciated that different shapes and dimensions of hooks may be used to provide alternative connection means. For example to accommodate different solar panel frames. The hook may include or comprise a clamp, G clamp, bracket, or interlocking part that is received by a corresponding part or region on the solar panel or frame of the solar panel or array.

Preferably the hooks are arranged to slot between adjacent modules so that the ladder spans the photovoltaic cells and so that hooks rest against a frame provided on a lower face of the solar panel. The brackets slide along the rails so that bracket can be aligned with the part of the solar panel against which the hook will rest. In some embodiments the hooks may include a resiliently deformable layer of material so as to protect the hook from damaging any part of the solar array.

It is appreciated that different hooks may be provided with the bracket in order to accommodate different solar panels.

Preferably the weight of the apparatus is borne by the frame of a solar panel upon which the solar panel is arranged. The ladder apparatus is adapted to engage with the frame so as to locate the apparatus on and over the module, fixing it in position during use.

The ladder apparatus is adjustable so as to provide a universal device that can be adapted to fit solar panels of different shapes and dimensions. For example, the ladder apparatus can be configured to be deployed for use over a module or array of solar panels in both portrait and in landscape orientations.

Preferably the ladder apparatus has a pair of sliding brackets arranged on a pair of substantially parallel rails.

In some embodiments the ladder apparatus may include two or more pairs of sliding brackets to permit multiple points of contact and support.

In some embodiments the rails may be have a shallow arch so as to span the module. The shallow arch limits the degree of flexion towards to module so that the rails do not sag during weight bearing such that the rails become too close to the module.

The sliding brackets includes a locking means for fixing the bracket at a desired location on the rail. In some embodiments the sliding bracket includes apertures through which a fixing such as a bolt can be passed through in order to lock the sliding bracket to the rail. In another embodiment the bracket may include a grub screw or a knob bolt that can be tightened so as to come into contact with the rail and lock the sliding bracket to the rail by means of friction. The sliding brackets support hooks, or are associated with a structure that supports hooks, so that the position of the hooks can be adjusted by sliding the sliding bracket along rails so that the hooks can be positioned to correspond with the frame of the solar panel. Preferable the sliding brackets, or associated structure that supports the hooks are arranged, and sized and dimensioned, to allow the hooks to fit in between the solar panels, even when arranged in an array. The ladder apparatus serves to transfer the weight of the ladder and user(s) onto strong region of the solar panel, typically the structure of the frame underneath the solar cells. As the brackets slide they can be moved to accommodate different frames or gaps between modules.

In a preferred embodiment the pair of sliding brackets is adapted to receive an elongate member extending therebetween from which a pair of hooks suspend. In this way the sliding bracket is associated with a structure (elongate member) from which the hooks are suspended. This arrangement allows the distance between each pair of hooks to be adjusted to correspond to the width of each solar panel, as the elongate member may be wider than the rungs, thus enabling the at least one hook to pass down the side of the solar panel reach a region on the lower face. The elongate member is arranged to slide beneath the rails and rungs such that the elongate member is suspended from the sliding brackets a distance that permits the elongate member to slide freely between the ladder apparatus and the solar panel.

Preferably the sliding bracket is adapted to receive an elongate member such that is the elongate member is anchored in position below the rungs. Ideally the sliding bracket is adapted so that the elongate member can be attached to or removed from the ladder apparatus. In this way the assembly and disassembly are easily permitted.

Preferably the hooks are supported by and suspended from a connector mounted on the elongate member. Ideally the connector is moveable long the length of the elongate member so that the distance by which the hooks are spaced apart can be adjusted to correspond to the width of a solar panel and/or the frame upon which the solar panel is arranged. It is appreciated that the elongate member may extend beyond the rails of the ladder such that the hooks can be positioned at a width greater than the ladder.

In this way the ladder apparatus can be adjusted to the length of the solar panel by positioning the sliding bracket along the rails and adjusted to fit the width of a solar panel by moving the connector and thereby the hooks along the elongate member to the desired position.

The connector is also adapted to permit connection of a hook. Typically the connector provides a clamp in which a hook is mounted and secured. The hook is attached to the connector so that hook extends downwards towards the solar panel.

Preferably the hook can be added to and removed from the connector. This permits assembly and disassembly. For example the connector may be a clamp assembly that removably receives the hook. In some embodiments each hook may be arranged on a pivot so that the that hook can be displaced, for example when being slid along the rails so as not to catch on a part of the frame that the hook is not intended to connect.

The pivot may include a locking mechanism such as a ratchet mechanism so as to prevent the hook swinging freely about the pivot and potentially damaging the solar panel.

The hook is typically provided at a distal end of an arm such that the length of the arm determines the distance by which the rails are separated from the solar panel.

The hooks may be provided in different shapes such as T-shaped (one hook) or F- shaped (two hooks). The hooks may be formed from plates cut using water-jet technology into T- shaped or F-shaped members. In some embodiments the brackets may comprise a plurality of hooks, or displaceable hooks, such that the hooks may be hooked onto or over more than one part of the frame, or so as to permit connection to different parts of a frame by one hook.

In some embodiments a hook with a plurality of hook portions may permit the ladder to be set different distances from the solar panel depending upon the work to be carried out.

In yet further embodiments the hook portion may include an adjustable arm, such as a telescopic arm to allow the hook to be spaced from the rail to a desired distance and ideally a means is provided to lock the hook in that configuration .

Typically the hook is received by the solar panel frame into a recess or channel. For example often a solar array frame may be formed from C-section. Ideally the hook is arranged to engage with the C-section. In this way the hook permits the ladder apparatus to hang from the solar panel at a fixed position and to bear weight as the hook bears on a recess defined by the C-section of the frame.

In some embodiments the hook is coated with a non-conductive material so as to prevent conduction through the ladder if part of the module accidentally became electrified, such as due to damaged cables.

A coating may be formed from a resiliently deformable material so as to prevent damage to the surface of a solar panel with which the hook is in contact. For frames that do not include recesses or channels for receiving a hook, or for which the alignment of the recess or channel does not correspond to the hook, the ladder apparatus includes an anchor bracket that is arranged on the frame for receiving the hook. The anchor bracket has an attachment means for connecting it to the frame and a channel for receiving the hook. Preferably the attachment means comprises clips that define a channel for hooking over the frame so as to be quickly and easily deployed and attached to the frame. In this way the at least one anchor bracket may thereby be enabled to clip over horizontally arranged parts of the solar panel frame by being hung by the clips. Preferably the rails are formed from a metal extrusion to provide a strong, lightweight structure suitable for supporting a user. Ideally the rails are in the form of an I-beam or strut. In some embodiments the rails are formed from box sections of rigid material.

In some embodiments the ladder may comprise more than one set of rails, for example so as to define a side depth to the ladder.

In a preferred embodiment there is provided an outer rail portion, furthest from the solar panel in use, and an inner rail section that is arranged closest to the solar panel in use. The upper and lower rail portions are preferably spaced apart by a body, which body has braces to strengthen the rails.

The braces may be in the form or diagonal struts, or the body may be a sheet arranged between the rail portions. The sheet may be provided with apertures so as to reduce weight of the rails. Preferably such apertures may be circular to maintain optimal strength.

In some embodiments lengths of rail sections may be connected together to enable compact storage and to enable the length of the rails to be adjusted for use.

It is appreciated that an extrusion may be drawn to include an inner and outer section with a body arranged between. Rungs are arranged between the rails to form a ladder and may be circular or triangular in cross-section.

The rungs may be removably connected to the rails, for example being connected with bolts. This permits the ladder apparatus to fully disassembled and packed into a compact container when not in use; or modified for use with non-standard solar panels. In other embodiments the rungs may be welded or bonded to the rails.

In some embodiments upper and lower rungs may be provided to create some rungs closer to the solar panel and some rungs further away from the solar panel. This may help an operative to best position themselves on the ladder depending upon the works to be carried out. For example, a lower rung may extend between lower rail sections and an upper rail may extend between upper rail sections.

In other embodiments the rungs may all be in the same alignment, for example being substantially central extending from the body of the pair of opposed rails.

In some embodiments the rungs of the ladder may be located in pairs so that, for example, rungs are provided between rails of a ladder and extend outwards from the ladder, thereby enabling a user to step beyond the parallel rails.

In some embodiments the rungs or sets of rungs of the ladder may be offset on the rails, for example some rungs on a lower rail (lower rungs) may have a different spacing to rungs positioned on an upper rail (upper rungs).

Optionally lower rungs may be arranged intermittently further along the rails than the upper rungs. In this way the sets or rungs may be arranged to provide support for a user when climbing the structure, and the sets of rungs may provide a substantially horizontal alignment when the structure is provided at a known photovoltaic array angle horizontally and vertically.

The rungs may be shaped and dimensioned to provide a surface that is horizontal in use, in this way items such as tools can be rested on the rungs to provide a work surface at height. The horizontal surfaces of the rungs may include lips to prevent items from falling from a rung.

In some embodiments the rungs may comprise one or more coaxial or telescopic portions so as to enable adjustment of a width or length of the ladder.

In some embodiments the rungs may be coloured so as to be clearly visible to user, for example the rungs may have black and yellow stripes.

The ladder includes an elongate sheet of material arranged below the rungs. The elongate sheet provides a protective layer between the user and the solar panel and serves to prevent dropped items from damaging the solar panel. Preferably the ladder apparatus may include attachment means for receiving the elongate sheet of material.

For example the rails may include projections upon which the elongate sheet rests in use.

In another embodiment the projections may be provided on the sliding bracket. In this way the elongate sheet is located between the rails. In some embodiments projections are attached at a pivot so that the projections can be moved in order to engage with and secure the elongate sheet in place.

In yet a further embodiment the ladder apparatus may include an attachment point for the elongate sheet, such as bolt on connection or a clamp.

Ideally the elongate sheet of material is formed from a strong, lightweight material such as a synthetic plastics material.

In a preferred embodiment the sheet may include a strengthened edge, section or region, such as metal, or metal alloy edging to provide improved rigidity. Ideally the edge is provided along the elongate parallel sides of the sheet. The edging, for example, may be attached to the sheet by adhesive or may be bolted to the sheet.

The elongate sheet may be transparent or translucent to enable visibility to the panel whilst the ladder is in use and so as not to inhibit energy generation.

In some embodiments the elongate sheet may include or comprise a lip, net or skirt to catch any dropped items (such as tools) thereby preventing them from sliding off the ladder apparatus onto the ground.

A solar panel or array of solar panels may be arranged in a plurality of orientations or arrangements, but typically at set angles to the horizontal. It is common for solar panels to be arranged at an angle of 22 degrees in the UK; different angles of inclination are preferred in different latitudes. Therefore the ladder apparatus is arranged on an angled surface and use of the invention enables a user to work at an optimum height and orientation irrespective of the location of the solar panels. It is appreciated that the brackets and associated hooks may be configured to sit correctly at these angles, or to be configured to a specific angle.

To ensure safety of a user each rung may include a harness anchor for receiving a safety line. Preferably the harness anchor has an attachment point in the form of an aperture through which a safety line, or clip attached to a safety line, can be secured. In this way a user can move the safety line from rung to rung as the move up and down the ladder. In preferred embodiments the ladder apparatus has a handle provided at each end of the rails. The handle enables the ladder part of the ladder apparatus to be moved to and positioned over a solar panel.

Ideally each handle is attached at a pivot so that the handle can pivot relative to the rails. The handle may be connected to the rails by a pin-in-recess arrangement or similar means that permits quick and easy removal. The pin may be provided on a tether to prevent the pin being separated from or falling from the apparatus.

In some embodiments the handle may be associated with a means of locking movement of the handle with respect to the rails. In this way the handle can be arranged to extend at a different angle relative to the rails.

Typically the handles fold downwards towards the ground when the ladder apparatus is in position. In some embodiments the ladder may provide addition rungs that enable a user to step more easily up to the solar panel. The portions of the handle that are stepped on may be coloured so as to be clearly visible to a user. These portions may also have a grip surface to prevent a user slipping during use.

It is appreciated that the handles may be used to arrange the ladder at the desired angle so that the structure can be walked over a solar panel or an array of solar panels.

In some embodiments the rungs have a grip surface so that a user is less likely to slip when using the ladder apparatus. In some embodiments the rungs may include padding for increased comfort during use. For example a user may need to rest against the rungs whilst maintaining the solar panel and if the run is padded this may prevent or reduce the likelihood of the user being bruised. The padding may extend over part or substantially the entire rung. Alternatively a separate pad may be provided which fits over the rungs so as to enable a user to kneel comfortably and perform installation, cleaning, repair or maintenance duties.

The ladder allows a user to climb or walk up the array and access the solar panels for installation of/maintenance or replacement purposes. In particular the user is enabled to access the modules on large ground mounted or rooftop commercial solar farms without placing pressure on the glass or the modules, advantageously removing the need for persons to stand directly on the glass/modules. The apparatus may be assembled on site wherein users carry and lift the ladder into place over the desired area of the solar array or panel to be worked on.

Once placed into position the array can be accessed from ground level by stepping up onto the first stepping bar whilst holding on for extra safety. The user can manoeuvre all the way to the top of the module array to install panels or carry out maintenance as desired.

In this way the apparatus provides a valuable tool for operations and maintenance (O&M) of solar farms. The apparatus solves the problem of maintenance by allowing users to gain access onto the solar array without transferring any weight of the frame or user(s) onto the solar panels.

In preferred embodiments the ladder apparatus includes a trolley adapted to receive the ladder and transport it to the location of use.

Preferably the trolley is adapted to securely and to hold the assembled ladder.

Advantageously the trolley is sized and dimensioned so as to be suitable for rolling on tracks so that the assembled ladder apparatus can be rolled to the desired location, spanning the solar array, and then be deployed. Optionally the trolley has wheels suitable for rolling over a face of a module, for example wheels with pneumatic tyres.

Ideally the trolley includes a set of wheels mounted in an alternative orientation for running along the top, side edge of the solar array such that the trolley is prevented from slipping down the solar array.

Preferably the trolley includes buckets for receiving the distal end of the hooks. In this way the ladder is secured in the trolley, the hooks are spaced apart from the solar panel, or array, during transport.

The buckets may be moveable so as to enable the sliding brackets to be positioned at the desired locations for use before placing on the trolley. In this way the buckets can be move to the necessary position for receiving the hooks.

A means for securing the trolley to the ground is provided. Preferably the means include at least one ground anchoring peg, each peg connected to the trolley by a line so that the peg can be driven into the ground to prevent movement of the trolley along the solar panel.

Ideally a pair of ground anchoring pegs is provided at each end of the trolley providing four attachment points to the ground.

Ideally the trolley is also suitable for rolling the ladder over the ground to reach the solar panel. It is appreciated that the trolley may be adapted for different uses, for example having wheels suitable for the ground and wheels suitable for a solar panel.

In some embodiments the ladder apparatus may be provided with a tracker to monitor location of the ladder apparatus. Advantageously this enables use of the apparatus to be monitored. Sensors or imagers such as cameras may be provided to obtain evidence of an event and safe use of the ladder on solar panels. In this way failure to use the ladder apparatus can be detected which would indicate that a cleaning or maintenance event has not occurred. Likewise sensor or camera data confirms safe usage to be easily monitored. The use of a tracker can also enable location of ladder apparatus to be recorded, for example for storage purposes or logistics of supplying or hiring a ladder to a customer or maintenance team. Typically the tracker is a surface mounted device with global positioning system (GPS or GSM) means. The tracker may have anti-tamper means so that location data cannot be adjusted or prevented from being sent.

Preferred embodiments of the invention will now be described by way of example only and with reference to the Figures in which:

Brief Description of Figures

Figure 1 shows a perspective view of an embodiment of the apparatus in use on a solar panel array;

Figure 2 shows a detail view of a second embodiment of the apparatus according to the present invention ;

Figure 3 shows a detail view of the embodiment as shown in Figure 2;

Figure 4 shows a detail view of the embodiment as shown in Figure 2;

Figures 5A, 5B and 5C shows a third embodiment of the ladder apparatus; Figure 6 shows an end view of the second embodiment of the ladder apparatus; Figure 7 shows a side view of the third embodiment of the ladder apparatus; Figures 8A and 8B show handles of a ladder apparatus; Figures 9A to 9F show various views of a rung;

Figures 10A to 10D show various views of a safety line attachment point; Figures 1 1 A an 1 1 B shows a rung section and a rail section; Figure 12 show side view of a pair of rails; Figure 13 shows and alternative embodiment of rail section

Figures 14A to 14D show an anchor bracket; Figures 15A and 15B show a trolley and ladder arranged on the solar panel; and

Figure 16 shows an alternative embodiment of the sliding bracket including a projection for receiving the elongate sheet. Detailed Description of Figures

The method of using the ladder apparatus includes the following steps.

Before the ladder apparatus is deployed the area of use must be identified and a suitable plan on how to access the area determined along with a safety check for any dangers.

The ladder apparatus is delivered and assembled and the sliding brackets are positioned as per the physical on site measurements of the solar panel(s).

The ladder is lifted into position, typically by two persons, using the handles (one person located at the back and the other at the front of the array) taking care to ensure the hooks associated with the sliding brackets pass through the gaps in between the solar panels and locate correctly onto the frame or into the anchor brackets mounted on the frame. The person standing at the back of the solar panel can visually guide on this step.

Once the ladder is correctly fitted into position a designated person fitted in a harness with a restricted lanyard for connecting to the rungs can begin to use the ladder. The user can reach the ladder by using the bars associated with the handle as steps to the ladder.

Method of use of the ladder with the trolley. If the carrier frame is to be used it must first be placed into position on the solar panel. The trolley is anchored to the ground using ground pegs to prevent it from moving away on its own. Once the trolley is in position the ladder can then be lifted/positioned by two persons onto the trolley, aligning the hooks with buckets on the trolley.

Once the ladder is located in the trolley the ground anchor pegs can be removed and the apparatus can be rolled along the solar panel(s) to the desired position.

Once the desired location is reached the trolley is stopped adjacent to where the ladder is required. The trolley is once again fixed in position by ground anchor pegs.

If required, anchor brackets can be mounted on the solar panel for receiving the hooks. Care must be taken to ensure cables are not impinged.

Once the trolley has been secured by the ground pegs the ladder is removed and secured in place by correctly position the sliding brackets so that hooks connect with the solar panel.

Once work in that area is complete the ladder can be reloaded to the trolley, the trolley repositioned and the ladder deployed at a second location.

Referring to Figure 1 , the pictured embodiment of the ladder apparatus 100 comprises two rails 10 comprising square box tube sections welded together in parallel with rungs 20 running between.

The rails 10 comprise two vertically spaced apart rail sections 1 1 A (upper rail section), 1 1 B (lower rail section) with bracing 12 therebetween to give the rails 10 a rigid strength over a long distance.

Various forms or bracing 12 are provided. Figures 1 , 3, 4, 5, 7, 12, 14A, 14B and 15 show rails 10 with diagonal bracing 12.

Figure 13A shows an alternative bracing with the upper and lower rail section connected by a sheet with circular cut outs 10A. The upper rail section 1 1 A is tubular, the lower rail section 1 1 B is U-shaped

Preferably the rails and rungs are formed from aluminium so as to be strong, durable and lightweight.

In Figure 1 the top face of the ladder further comprises a plurality of rungs 20 periodically spaced apart and consisting of box section tube aluminium welded onto rails 10 to create steps which the user uses to access to the top of the array in use.

As shown in the second embodiment shown in Figures 2 to 4 the lower rail 1 1 B may have a plurality of basal rungs 20B arranged less frequently between the rails 10, so as to provide a sturdy construction. Such basal rungs may be offset so as to provide a substantially horizontal alignment with the upper rungs in use.

The rungs 20, as shown in the first embodiment (Figure 1 ), may have a foam or rubber coating or padding 21 for comfort and to protect the knees. The padding 21 is arranged proximate the rails 10, providing approximately a third coverage at each end wherein a central part of the rungs 20 are not covered. In this way the user is enabled to stand on the central part of the rung 20 without risking slippage of feet or padding.

The rails 10 comprise an upper rail 1 1 A, and a lower rail 1 1 B, wherein the bracing 12 is arranged to extend in a zigzag arrangement at 45 degrees to the top and bottom rails 1 1 A, 1 1 B.

The apparatus further comprises a handle 30 at each end of the ladder. The handle 30 secures to both rails 10 when in use. Once the ladder has been carried to the location of use the handles can be folded downwards to the ground to provide legs. The legs may be variable in angle with respect to the rails 10. The legs may also be telescopic so as to variable with regards to height.

The handle 30 on the top enables the ladder 30 to be carried and positioned carefully into place where required, wherein the top handles may be large so as to allow the apparatus to be lifted up around 2-3 metres high dependant on the array. Such handles may also be rubber/plastic coated for comfort and health and safety reasons. The coating is also preferably non-conductive.

The apparatus comes in two parts and will be assembled on site when needed so as to be easier to transport.

Figure 2 shows a second embodiment of the ladder apparatus with a hook 50 suspended from a sliding bracket (not shown) extending downwards between adjoining solar panels 500. The hook 50 is F-shaped with a distal hook below the solar panel and a second hook visible.

Figures 3 shows a hook 50 extending from a sliding bracket 40. The hook 50 is welded to the sliding bracket 40. There are two hooks 50A, 50B extending from the arm 51 . In use the hook 50 rests on the frame of the solar panel (not shown) so as to space the ladder apparatus from the solar panel 500.

The sliding bracket 40 has a grub screw 41 for locking the sliding rail in place.

The hooks 50 are formed of 10mm aluminium plate which is small enough to fit in between the lateral gaps between modules 500 and make contact with the sturdy structure frame system underneath the solar panels 500.

In Figure 3 there are two hooks 50 that are spaced apart appropriate the depth of the solar panel and are radiused to limit damage to the array. In some embodiments the sliding brackets 40 may include a plurality of hooks, or displaceable hook, so as to adjust to different depths.

In the pictured embodiment there are envisaged to be eight of these hooks 50 on the ladder, arranged four to each rail 10, so as to allow points of support on and contact with the array frame underneath the modules 500.

As shown in Figure 4 the bracing 12 provided between the upper and lower rails 1 1 A, 1 1 B further includes orthogonal bars 13 and bars 14 parallel to the top and bottom rails 10. The rails 10 provide a body along which a sliding bracket 40 can slide. The sliding brackets 40 extend from and below the lower rail 1 1 B. The sliding bracket 40 is adapted to fit about the rail 1 1 B. Typically the sliding bracket has a channel that corresponds to the rails 10. The channel may include a return 43 (see Figure 5C) so as to secure the sliding bracket about the rail during sliding.

The sliding bracket 40 has apertures 44 that correspond to apertures on the rails 10. In Figure 1 1 A the lower rail 1 1 B has an aperture through which a fixing can be arranged. In this way the sliding bracket 40 can be locked to the rail in a fixed position, for example by a nut a bolt or similar fixing means.

In some embodiments the sliding bracket does not include a return and is held in position by a fixing means.

The sliding bracket 40 can be locked in place by a screw threaded locking means 41 . Other locking mechanism may be used, for example a pin and hole arrangement. In Figures 3 and 4 there is shown a grub screw arrangement in which when the grub screw is tightened by turning the grub screw 41 causes contact of the grub screw with the lower rail 1 1 B to provide a friction lock.

By release of this friction lock the sliding brackets 40 can slide up and down the frames to fit different solar panel framing systems.

The ladder apparatus thereby transfers the weight of the ladder and user(s) onto the subordinate array frame underneath the modules to leave zero pressure on the solar panels and the glass of the solar panels.

The hooks 50 have a non-conductive coating (not shown), typically rubber/plastic coating to prevent the flow of electric in case of damaged cables for health and safety reasons. The costing also protects the frame from damage by the hooks. Figure 5 shows a third embodiment 300 of the ladder apparatus. The rails 10 are formed from a metal extrusion with the lower section of the extrusion adapted to receive a sliding rail 40. The sliding rail 40 is adapted to hold an elongate member 60. The sliding bracket 40 has an opening 42 for receiving the elongate member 60. The elongate member 60 extends between a pair of sliding brackets 40. The elongate member hangs below the rails 10. The elongate member 60 also receives connectors 61 which are slidably mounted on the elongate member and are also adapted to receive the hooks 50. The connectors 61 shown in Figure 5 have square sections 62 that corresponds to the elongate member 60. The connectors 61 can be slid on the elongate member 60 to adjust position of the hooks 50.

The connectors have a clamp 63 for receiving a hook 50. The arm 51 of the hook 50 is sandwiched between the clamp 63. Corresponding apertures (not shown) are aligned and a bolt is passed through the aligned apertures in order to form a connection.

Each rung 20 has a safety line attachment point 22 for securing the safety of user climbing the ladder apparatus. The safety line anchor point has an aperture 22A for receiving a line or clip. The ladder apparatus 300 in Figure 5 also has an elongate sheet 70 that prevents dropped items from contacting the solar panel.

Figure 6 shows an end on view of the third embodiment of the ladder apparatus. Figure 7 shows a side view of the third embodiment of the ladder apparatus.

Figures 8A and 8B shows an example of a pair of handles 30A, 30B and indicated preferred dimensions. The larger handle 30A shown in Figure 8A is intended to enable the ladder apparatus to be lifted over the highest part of the solar panel. Close up image C shows how two box sections weld together such that part of the handle can slide inside another part. Close up B shows a close up of two box sections welded together and then welded to the outside box allowing the internal frame to slide inside. This is also a crimp box bracket with a hole and a rivet nut fitted. The smaller handle 8B is arranged in use at the lowest part of the solar panel and may also serve to provide additional steps to the ladder. Close up A shows two box sections welded together to the outside box allowing the internal frame to slide inside. This is also a crimp box bracket with a hole and a rivet nut fitted. Figure 9 shows different views of a second embodiment of a rung 20. The rung 20 as a triangular cross section and includes an internal rib. The rung ends includes a plate 23 that is for joining the rung to the rails. The rungs 20 can be bolted to the rails 10. Figure 10 shows different views of the safety line attachment point 22. A first portion of the safety line attachment point 22B has an aperture 22A. The first portion is angled with respect to the second portion 22C that attaches to the rung 20. This angle makes it easier to connect the safety line to the aperture 22A without the rung interfering. Typically the angle between the portion 22B and 22C is 146 degrees.

Figure 1 1 shows a cross section of the rung 20 (Figure 1 1 A) and a cross section of the rail 10 (Figure 1 1 B). Preferred dimensions are indicated.

Figure 12 shows side views of the rails 10 indicating preferred dimensions.

Figures 13A, Figure 13B shows an alternative embodiment of rail section 10 in which the rail has circular cut out sections to reduce 10A the overall weight of the rail and to improve strength. Figure 13A shows a side view of the rail 10 with circular cut out sections 10A arranged along the length of the rail 10.

Figure 13B shows a cross section of the rail 10 with a tubular upper rail 1 1 A and a U- shaped lower rail 1 1 B. Figure 14 shows an anchor bracket 80 that may be hung from the frame of a solar panel. The anchor bracket 80 is for receiving the hooks 50 of the ladder apparatus 100, 200, 300, if the frame of the module does not provide a suitable mounting position for the hooks.

The anchor bracket 80 has two clips 81 that hook over part of the frame, in use, so as to provide a channel 82 in the correct orientation for receiving a hook 50.

Figure 15 shows a trolley 90 arranged on a solar array 500. The trolley 90 has a frame 93 with six wheels 92 arranged on the face of the modules 500 and a pair of wheels 94 arranged on a top, side edge of the solar panel (See Figure 14B). The frame 93 is formed from tubular sections. The wheels 92 are spaced to correspond to the edges of the solar panels 500. The wheels 92 that contact the face of the solar panel 500 have pneumatic tyres. The wheels 94 that travel along the side edge of the module 500 are smaller and may not be pneumatic, for example having solid tyres.

The trolley 90 has four buckets 91 for receiving the hooks of the ladder. The buckets 91 locate the hooks and ensure the ladder stays in position as it is rolled over the solar array. The buckets 91 are mounted on the frame 93.

The position of the buckets 91 can be adjusted to correspond to the position of the hooks. Once the desired location is reached the ladder 100 can be lifted from the trolley 90 and position of the solar array 500.

Figure 16 shows an alternative embodiment of the sliding bracket 40 including a projection 45 for receiving the elongate sheet 70. The projection 45 provides a ledge on which the sheet is positioned in use. The invention has been described by way of examples only and it will be appreciated that variation may be made to the above-mentioned embodiments without departing from the scope of invention as defined by the claims.