NL2009711C2

NL2009711C2 - Bearing construction and tracking system provided therewith.

Info

Publication number: NL2009711C2
Application number: NL2009711A
Authority: NL
Inventors: Jan Kranendonk; Thomas Leeuw
Original assignee: Sunuru Holdings B V
Priority date: 2012-10-29
Filing date: 2012-10-29
Publication date: 2014-05-01

Description

BEARING CONSTRUCTION AND TRACKING SYSTEM PROVIDED THEREWITH

The present invention relates to a bearing construction, as well as to a tracking system, especially an 5 orbital tracking system such as a solar system, provided therewith. Other orbital tracking systems the invention could be applicable to are systems for tracking other heavenly bodies and satellites.

High-efficiency solar systems aimed at achieving 10 the highest efficiency possible are solar systems that are capable of tracking the orbit of the sun along two axes, so that it is capable of orientating every single solar cell of said solar system towards the sun.

A beneficial solar system capable of following the 15 sun's movement is the solar system proposed by the same Applicant in WO-2012/064189. This system comprises a plurality of solar units suspended between two substantially parallel nets, that can be moved relative to each other by drive means. By moving the nets relative to each other, the 20 solar units can be directed towards the sun all at once.

This system is far more simplified than prior art solar systems that comprise an electric drive for every solar unit or every panel of photovoltaic elements. Moreover, these prior art systems are heavy, and the large amount of 25 electric drives requires maintenance and possibly replacement of motors that have failed.

While moving the nets of the solar system of W0-2012/064189 relative to each other for aiming the multiplicity of solar units towards the sun all at once, 30 tension was build up in the net structure. Although this tensioning is within acceptable limits for building a non heavy solar system of around 50 small solar units, it is desirable to further reduce the tensioning in the net 2 structure in order to allow even larger solar systems in the future .

Furthermore, while the solar system of W0-2012/064189 is aimed at achieving the highest efficiency 5 possible, there might be occasions wherein it is beneficial to further simplify the construction of the solar system, even if it is at the expense of a slightly lower efficiency thereof .

An object of the present invention is to provide a 10 tracking system, especially an orbital tracking system such as a solar system, that is improved relative to the prior art and wherein at least one of the above stated problems is obviated.

Said object is achieved with the bearing 15 construction for a tracking system, according to the present invention, said bearing construction comprising: - an attachment member, that is configured for engagement with a tracking element of said tracking system; - wherein the attachment member is arranged on at 20 least two cords that are attachable between at least two opposite attachment locations of said tracking system; - wherein said cords comprise at least two intertwined portions that are twined in the same coiling direction and that are aligned along a joined rotation axis; 2 5 and - wherein the attachment member is arranged between two associated adjacent intertwined portions.

In this application, a number of definitions is used.

30 Firstly, one 'turn' is defined as one rotation of 180° around a rotation axis.

Secondly, a ‘'winding' is defined as a series of abutting turns. Hence, it can be considered a portion 3 wherein the cords are spirally wound around each other as a result of a mutual rotation of more than 180° around the longitudinal axis of a joined rotation axis.

Furthermore, the cords according to the invention 5 might comprise an untwined and an intertwined portion. The 'intertwined portion' is defined as the portion where the winding is located, e.g. where the cords are wound around each other forming abutting turns. An 'untwined portion' is a portion where the cords are not intertwined.

10 According to the invention, the intertwined portions are twined in the same coiling direction. The 'same coiling direction' is elucidated by considering the right-hand grip rule or the corkscrew-rule or the right-hand thumb rule frequently used in mathematics and physics. This rule 15 is e.g. used in situations where a vector must be assigned to the rotation of a body. If a person grips the imaginary axis of rotation of the rotational force so that his/her fingers point in the direction of the force, then the extended thumb points in the direction of the torque vector. 20 Likewise, if a person would grip with his/her fingers the coiling direction of two associated intertwined portions, the thumb would point in the same direction.

By arranging associated intertwined portions in one line, they jointly form a rotation axis. Intertwined 25 portions which are twined in the same coiling direction, and which are also aligned along a shared rotation axis, provide a bearing construction especially suitable for orbital tracking systems that comprise nets for suspending tracking elements. When the attachment member, that is arranged 30 between two adjacent intertwined portions, is rotated, a first intertwined portion on one side of the attachment member will wind further and grow with one or more turns, while a second intertwined portion on a second side of the 4 attachment member will unwind with the same amount of turns. Hence, the winding on the one side is completely counteracted by a corresponding dewinding on the opposite side, resulting in an unchanged length of the cords. In this 5 way, stresses that would arise due to a change in length of the cords is prevented.

Furthermore, rotation of the attachment member, that is adapted for engagement with a tracking element of said orbital tracking system, is almost without friction, 10 while high tensioning of the cords is possible.

The bearing construction according to the invention functions as an axial bearing that is especially suitable for orbit tracking systems, because: 1. it is high-load resistant; 15 2. especially suitable for back- and forth rotational movement; 3. at very low rotational speeds of less than 0.0007 RPM; 4. by using a simple and robust design; 20 5. that has no moving parts; and 6. requires almost no maintenance.

Prior art orbit tracking systems normally apply traditional heavy duty bearings that are typically designed for continuous rotation at moderate rotational speeds of 300 25 RPM or more. The rotational speeds are more than 400.000 times faster than the required 0.0007 RPM of solar tracking systems. Such traditional heavy duty bearings bearings represent a major risk factor for lifetime and require maintenance. Moreover, they make up for a significant 30 portion of the total system costs.

Furthermore, a bearing construction for a solar tracking system could be designed for less than 10.000 back-and forth rotational movements over it's lifetime, whereas 5 traditional heavy duty bearings are typically designed for more than 100.000.000 rotations over their lifetime: a difference of factor 10.000.

The bearing construction according to the 5 invention allows for a single net structure, thereby providing a solar system that is even further simplified relative to the solar system shown in WO-2012/064189, that in itself was already significantly simplified with respect to prior art solar systems as described above.

10 Furthermore, the bearing construction reduces tension build up in the net structure, allowing for net structures with even wider span dimensions than before. This advantage is also applicable to solar systems comprising two nets than are moved relative to each other, as e.g. the 15 solar system of WO-2012/064189.

According to a preferred embodiment, the bearing construction further comprises: - an untwined portion directly adjacent each intertwined portion; and 20 - wherein said cords of said untwined portion diverge away from each other in the direction extending from their adjacent intertwined portion.

Due to the diverging away of the two cords, the turns remain 'compressed'' in the intertwined portion. This 25 prevents distribution of the turns of the winding over the whole length that is available, e.g. between the attachment member and the attachment locations.

According to a further preferred embodiment, both untwined portions that are associated with two neighboring 30 intertwined portions are directed towards each other, and wherein the attachment member is arranged between said untwined portions. Because the cords diverge away from each other in the untwined portions, the cords are arranged on 6 the attachment member at a mutual distance. This provides a more stable arrangement of the attachment member on the cords .

According to a further preferred embodiment, the 5 cords are attached to the attachment member near opposite edges thereof. When the cords are arranged on the attachment member near the opposite edges thereof, the distance between the cords is maximised, resulting in the most stable arrangement possible.

10 According to a further preferred embodiment, the intertwined portions comprise at least a number of turns identical to the required number of rotations of 180° of the attachment member, wherein one turn is defined as one rotation of 180° around the rotation axis that is jointly 15 defined by two aligned intertwined portions. During rotational movement of the attachment member, the windings will wind and unwind. By providing at least a number of turns identical to the required number of rotations of 180° of the attachment member, it is ensured that the attachment 20 member can pass through the required rotational movement.

For a solar tracking system, the orbital tracking system should ideally be able to follow the complete path from sunrise in the East to sunset in the West. This path of 180° requires a minimum of one turn.

25 Furthermore, in order to always have one remaining turn in order to encompass the wires of the net structure that form the attachment locations of the orbital tracking system, one further turn is preferred. Hence, ideally, each intertwined portion comprises at least two turns for each 30 winding.

Although the attachment member could be connected with the opposite attachment locations with independent cords, it is a preferred embodiment that the attachment 7 member is arranged on a continuous part of the cords. This simplifies the construction due to the absence of knots or other ways of attachment.

Preferably, continuous cords are arranged between 5 the two opposite attachment locations of the orbital tracking system. These continuous cords are due to the absence of knots, that would weaken the cords, especially suitable for high tensioning.

According to a further preferred embodiment, the 10 attachment member is slidably arranged on the cords. A

sufficient length of the cords in the untwined portion would result in sufficient flexibility to account for cord changes due to winding on the one side and unwinding on the opposite side. However, a slideable arrangement could slide in order 15 to average out any stresses between the untwined cord portions on both sides of the attachment member, even if the cords in the untwined portion are relatively short.

A slideable arrangement of the attachment member on the cords provides the further advantage that the 20 untwined portion can be relatively short without a negative effect on the ease at which turns can be added to or removed from a winding during respectively winding or dewinding thereof .

According to a further preferred embodiment, the 25 cords are metal wires. Of course, other suitable materials that can bend without plastic deformation are also applicable .

According to a further preferred embodiment, the intertwined portions and untwined portions comprise at least 30 three cords. Three or more cords allow for a more stable, e.g. truss-like, construction.

The invention is further directed to a tracking system, especially an orbital tracking system such as a 8 solar tracking system. According to a first aspect of the invention, said tracking system comprises: - a plurality of tracking elements; - suspension means for suspending the plurality of 5 tracking elements, said suspension means comprising a net; - drive means, comprising connecting members interconnecting a series of tracking elements such that said interconnected series of tracking elements is simultaneously adjustable via the drive means; 10 - wherein the suspension means comprise attachment locations to which the tracking elements are attachable; and - wherein the net of the suspension means comprises wires that form the attachment locations to which the tracking elements are arranged via a bearing 15 construction according to the invention as described above.

The single net structure with the bearing construction according to the invention provides an orbit tracking system that is even further simplified relative to the solar system shown in WO-2012/064189, that in itself was 20 already significantly simplified with respect to prior art solar systems as described above.

Furthermore, it provides a solar energy system that can be easily transported to remote locations, since it requires only limited space in collapsed state, and 25 furthermore comprises mainly lightweight components. For example, (metal) wires of a relatively thin cross sectional area are able to withstand the high tensile forces required for pre-tensioning the net structure. A profile beam structure - as applied in conventional solar energy system 30 for supporting solar panels - that spans the same distance would be significantly heavier.

The connecting members can be a flexible drive member such as a belt, wire, cable, chain or the like.

9

According to a preferred embodiment of the orbital tracking system, every tracking element is only connected to one single net.

According to a further preferred embodiment, the 5 tracking elements are arranged in a grid, and wherein a plurality of tracking elements arranged in a row or column of the grid are driveably connected via the drive means. The drive means drive a series of tracking elements, such as a number of tracking elements that are arranged in a line 10 simultaneously. This line can be a row or column of a grid.

The invention is further directed to a tracking system, especially an orbital tracking system such as a solar tracking system, according to a second aspect of the invention, said tracking system comprises: 15 - a plurality of tracking elements; - suspension means for suspending the plurality of tracking elements, said suspension means comprising a first net and a second net oriented parallel in a plane, a distance existing therebetween; 20 - wherein at least two drive means are arranged to the suspension means such that the first and second net are moveable relative to each other in the plane by the drive means; - rotation limiting means configured to limit a 25 rotation of one or more tracking elements with respect to the suspension means; - wherein every tracking element is arranged to both the first and second net such that the orientation of the tracking elements is adjustable via the drive means 30 driving the suspension means; and - wherein wires of the nets of the suspension means form attachment locations to which the tracking 10 elements are arranged via a bearing construction according to the invention as described above.

The tracking system according to the second aspect of the invention uses a structure that is build out of nets.

5 By using the principle of tension, a very strong, lightweight structure is possible, that is easily produced on a large scale. Also, by moving the nets relative to each other, solar units that are connected to the nets can be aimed at the sun all at once. This structure is completely 10 modular and requires only two drives.

Moreover, the net structure provides a solar energy system that can be easily transported to remote locations, since it requires only limited space in collapsed state, and furthermore comprises mainly lightweight 15 components.

According to a preferred embodiment, the solar energy system comprises only two drive means, as this suffices for all movements required for the solar units to follow the path of the sun during the day and for each 20 successive day over the year.

According to a further preferred embodiment: - the solar unit is attached to the first net with a first attachment point; - the solar unit is attached to the second net 25 with a second attachment point; - wherein said two attachment points define a first rotation axis; and - wherein the rotation limiting means are configured to limit the rotation of the one or more solar 30 units with respect to the suspension means around said first rotation axis.

According to a further preferred embodiment, the rotation limiting means comprise at least one further 11 attachment point attaching the first net and/or second net to the solar unit, said at least one further attachment point defining an imaginary plane with the first and second attachment points, and preventing the rotation of the one or 5 more solar units with respect to the suspension means around the first rotation axis.

The rotation limiting means are comprising that at least one of the plurality of solar units is attached to the first and second net of the suspension means with a total of 10 at least three attachment points, said three attachment points together defining an imaginary plane and thereby preventing the rotation of the one or more solar units with respect to the suspension means around the first rotation axis .

15 If both first and second net would each only comprise a single attachment point with the solar unit, a rotation axis around which the solar unit could rotate would be defined through these two points. The at least one further attachment point provides a moment arm that allows 20 the moment of force that would rotate the solar unit to be compensated with. This torque compensation is achieved by the net structure counteracting any moment force.

Because the three attachment points together define an imaginary plane, an in-line placement of said 25 points is prevented. This ensures that the third attachment point provides a moment arm that allows the moment of force that would rotate the solar unit to be compensated with.

According to a further preferred embodiment, the at least one further attachment point is attached 30 substantially close to a corner of the solar unit.

Attachment near a corner allows the moment arm that is configured for counteracting the moment of force that would 12 - if not compensated - rotate the solar unit, to be maximized.

According to an alternative embodiment, the rotation limiting means comprise a rigid fixing member 5 attached to both the suspension means and one or more the solar units. Although net structures are preferred because they provide the additional benefit of a foldable and therefore easily transportable solar energy system, one or more rigid fixing members could also function as rotation 10 limiting means for preventing rotation between a solar unit and the suspension means.

According to a further preferred embodiment the first net is an upper net, and the second net is a lower net.

15 According to a further preferred embodiment the upper and lower net are arranged in a substantially lying plane .

According to a further preferred embodiment, the attachment locations are wires of the first net and second 20 net of the suspension means, and at least two cords are connected to a wire of the first net and at least two cords are connected to a wire of the second net.

According to a further preferred embodiment applicable to both orbital tracking systems according to the 25 first and second aspects of the invention, a series of associated tracking elements is arranged on the tracking system with one or more bearing constructions that comprise intertwined portions with the same coiling direction.

During rotational movement of an attachment member 30 and its associated tracking element, the winding on a first side of the attachment member will grow, i.e. wind up, while the winding on the opposite side of the attachment member will dewind. As a result of the winding on the first side 13 obtaining more turns, while the winding on the opposite side loses the same amount of turns, the attachment member will slightly move in the direction of the dewinding side. By providing a series of associated tracking elements with the 5 same coiling direction, the mutual distance between the series of associated tracking elements remains constant during joined rotation of said tracking elements.

According to a further preferred embodiment the attachment member is an integrated part of the tracking 10 element.

According to a further preferred embodiment, the orbital tracking system is a solar tracking system, wherein the attachment member is configured to receive a solar unit as tracking element.

15 In the following description preferred embodiments of the present invention are further elucidated with reference to the drawing, in which:

Figure 1: is a perspective view of a solar system with a single net structure according to the invention; 20 Figure 2: shows a bearing construction of the solar system shown in figure 1;

Figure 3: shows a schematic view of drive means for adjusting a series of solar units at once according to a first embodiment; 25 Figures 4 and 5: show schematic views of drive means for adjusting a series of solar units at once according to a second embodiment in a first state (figure 4) and in a second state (figure 5);

Figure 6: shows a schematic view of drive means 30 for adjusting a series of solar units at once according to a third embodiment;

Figures 7A and 7B: show a bearing construction with a non-preferred winding; 14

Figures 8A and 8B: show a bearing construction with a preferred winding according to the invention; and

Figures 9-11: show three alternative embodiments of a bearing construction according to the invention; 5 Figure 12: shows the solar system of W0- 2012/064189 provided with a bearing construction according to the invention; and

Figure 13: shows a detailed perspective view of the solar system of figure 12.

10 The tracking system shown in figure 1 is an orbital tracking system, and more specifically a solar energy system 100. The tracking elements 101 are solar units 102 that are suspended by suspension means 104. Said suspension means comprise a net structure 105 with a single 15 net that is arranged between support members 136 and comprises outer main suspender cables 138 and wires 124. The main suspender cables 138 and the wires 124 together form the web structure of the net 105. The solar energy system 100 comprises a grid of eighteen solar units 102, which are 20 arranged in six columns and three rows.

The arrangement of the solar units 102 on an attachment member 8 of a bearing construction 1 according to the invention is described with reference to figure 2. The bearing construction 1 is attached to two wires 124 of a net 25 structure, e.g. net structure 105 of figure 1. The bearing construction 1 according to the invention is also applicable to an alternative orbit tracking system 200 as shown in figures 13 and 14. The wires 124, 224 shown in figure 2 function as opposite attachment locations 111, 211 of the 30 orbital tracking system, such as the single net solar energy system 100 (figure 1) or the double net solar energy system 2 0 0 (figure 13) .

15

Two cords 2 are arranged between the attachment locations 111, 211 and comprise at least two intertwined portions 4a, 4b that are twined in the same coiling direction and that are aligned along a joined rotation axis 5 10. An attachment member 8 is arranged on these two cords 2.

The attachment member 8 is configured for engagement with a tracking element 101, 201 of said orbital tracking system. In the single net solar energy system 100 (figure 1) this tracking element 101 is a solar unit 102, 10 and in the double net solar energy system 200 (figure 12) this tracking element 201 is a solar unit 202.

In the embodiment shown in figure 2, there are arranged two attachment members 8 between the two associated adjacent intertwined portions 4a, 4b. It is however also 15 possible that one single attachment member 8, or more than two attachment members 8, are arranged between associated adjacent intertwined portions 4a, 4b. Said multiple attachment members 8 than perform a joined rotational movement.

20 The drive means 110 of the single net solar energy system 100 shown in figure 1 drive a series of solar units 102 that are arranged in a row of the grid. The drive means 110 drives the movement of the most right solar unit 102, and via connecting members 109 the other solar units 102 in 25 the row are moved jointly.

Figure 3 shows a first embodiment of the drive means 110 wherein every attachment member 8 comprises a pulley. The rotational drive 162 drives a pulley that is drivably connected via a connecting member 109 to the 30 pulleys of the attachment members. The connecting member 109 is a belt 166 or chain, and via the rotational drive 162 driving the first pulley, all connected pulleys of the attachment members 8 are rotated.

16

Figures 4 and 5 show two successive states of a second embodiment of the drive means 110. The rotational drive 162 drives a rod, that is connected via a connecting rod member 168 with rods 170 near each attachment member.

5 The rod driven by drive 162, the rod member 168 and the rods 170 together form an articulated system of rods. The rods 170 are connected via a further rod member 172 to the rotational axis of the associated attachment member 8, so that it transfers the rotational movement of the axle 163 of 10 the rotational drive 162 to the attachment member 8.

Figure 6 shows a third alternative embodiment of the drive means 110, that is closely related to the embodiment shown in figures 4 and 5. However, instead of a rotational drive 162, now a linear drive 164 with a driven 15 piston member 165 is used for moving rod member 168.

The cords normally diverge away from their attachment points on wires 124 towards their attachment points on an associated attachment member 8, because the attachment points on the attachment member 8 are preferably 20 arranged at some mutual distance in order to have the attachment member 8 arranged in a stable way.

When the two cords 2 are independently and directly attached in a (not shown) joint to a wire 124 of a net structure 105, they are independently pulled outwards of 25 the joint, and this pulling force is in different directions. In practice, this sometimes resulted in failure due to splitting of the joint as a consequence of the heavy pulling loads tearing the joint apart.

In order to reduce the above mentioned joint 30 problems between the cords 2 and the wires 124, 224 of the orbital tracking system, the cords 2 were twined such that they encompass the wires 124, 224 that form the attachment locations 111, 211 of the orbital tracking system. By 17 encompassing the wires 124, 224 of the net structure 105, 205 the joints between the cord 2 and the wires 124, 224 are more robust than non-twined wires. The intertwined portions 4a, 4b result in the cords 2 first pulling on each other in 5 the winding region, thereby together as one applying a pulling force in a single direction on the wires 124, 224. A splitting force on the joint is thereby prevented.

During first tests, the cords 2 were twisted around the wires 124, 224 via a rotational movement of the 10 attachment member 8. During this twisting, the attachment member 8 was not yet connected via connecting members 109 to neighboring tracking elements 101. This resulted in intertwined portions 4a, 4b with opposite coiling directions (figure 7A). After applying the winding, the connecting 15 members 109 were arranged between the attachment members 8, also preventing unwinding of the intertwined portions 4a, 4b.

The embodiment shown in figure 7A provides more robust joints, wherein the above mentioned splitting forces 20 and accompanying failure was prevented. However, the intertwined portions 4a, 4b with opposite coiling directions had the drawback that it introduced stresses to the net structure 105, 205.

When the attachment member 8 was rotated, it 25 resulted in winding or dewinding at both intertwined portions 4a, 4b. When both intertwined portions 4a, 4b were wound, meaning that additional turns were edit to the intertwined portions 4a, 4b, tensioning was introduced between the wires 124, 224 of the net structure 105, 205.

30 The wires 124, 224 are pulled together over a distance D (figure 7B) .

By disregarding the obvious fabrication method as described with reference to figure 8A, Applicant applied an 18 alternative and more complex fabrication method in order to test intertwined portions 4a, 4b that have the same coiling directions (figures 8A and 8B). Because the two associated adjacent intertwined portions 4a, 4b now have the same 5 coiling direction, the length of the cords 2 is maintained during rotation of the attachment member 8.

Between the states shown in figures 8A and 8B, the intertwined portion 4a on the upper side in figure 8B is increased with one extra turn, while the intertwined portion 10 4b on the lower side of figure 8B is decreased with one single turn when comparing it with the state shown in figure 8A. Hence, the winding on the upper side is completely counteracted by a corresponding dewinding on the lower side of figure 8B, resulting in an unchanged length of the cords 15 2. In this way, stresses that would arise due to a change in length of the cords (as in figure 7B) is prevented.

The total number of turns, i.e. the sum, of two associated adjacent intertwined portions 4a, 4b remains the same when the attachment member 8 is rotated between the 20 states shown in figures 7A and 7B. However, the number of turns belong to one specific winding does change, because one of the intertwined portions 4a, 4b will wind up one or more turns, while the other of the intertwined portions 4a, 4b will dewind the same amount of turns.

25 A further advantage of both associated intertwined portions 4a, 4b having the same coiling direction, is that there is no tendency to unwind, as was the case with the embodiment shown in figures 7A and 7B. Consequently, the connecting members 109 will not have to continuously resist 30 a preloading.

Figures 9-11 show three alternative embodiments of a bearing construction 1 according to the invention.

19

In all three alternative embodiments, the diverging away of the two cords 2 has the effect that the turns remain 'compressed'' in the intertwined portions 4a, 4b. This prevents distribution of the turns of the winding 5 over the whole length that is available, e.g. over the whole length between the attachment member 8 and the attachment locations 111, 211.

The cords 2 of the untwined portion 6a, 6b form a triangular shape with the attachment member 8, and this 10 triangular shape remains mainly unchanged when the attachment member 8 is rotated, provided the untwined portions 6a, 6b are long enough.

On both sides of the attachment member 8, the cords 2 arrive at the intertwined portions 4a, 4b at 15 substantially the same angle. As a consequence, the winding of the intertwined portions 4a, 4b will more or less have an identical 'compressed' shape on both sides of the attachment member 8. Hence, the difference in length of both intertwined portions 4a, 4b as a result of respectively 20 addition and subtraction of one or more turns, will be substantially equal. The resistance against respectively winding and dewinding will be also substantially equal on both sides, resulting in a low-resistance rotation of the attachment member 8.

25 The embodiment shown in figure 9 is the preferred embodiment, because the relatively wide mutual distance between the attachment of the cords 2 to the attachment member 8 results in a stable bearing construction 1.

Also the alternative embodiments shown in figures 30 10 and 11 comprise an attachment member 8 that is arranged between two associated adjacent intertwined portions 4a, 4b that have an untwined portion 6a, 6b directly adjacent said intertwined portion 4a, 4b. The cords 2, of the untwined 20 portion 6a, 6b diverge away from each other in the direction extending from their adjacent intertwined portions 4a, 4b.

The solar energy system 200 shown in figure 12 comprises a plurality of solar units 202 suspended by 5 suspension means 204, said suspension means comprising an upper net 206 and a lower net 208. The solar units 202 are attached to both the upper net 206 and lower net 208.

The upper and lower net 206, 208 are arranged with their respective corners 220, 222 to rigid spacing elements 10 226, 228. In the embodiment shown in figure 12, the rigid spacing elements 226 are driveable via drive means 210, whereas the opposite rigid spacing elements 228 is pivotably arranged to the tensioning member 230.

The solar units 202 are arranged to both the upper 15 net 206 and lower net 208, and will undergo an angular movement when the upper and lower net 206, 208 are moved relative to each other in their the plane, i.e. their inplane direction.

The structure of the inner wires of the nets 206, 20 208 is such that any solar unit 202 arranged between the nets is able to move freely without getting into contact with itself, other solar units 202, or the nets 206, 208.

By moving the nets with respect to each other, it is possible to "aim" the solar units 202 hanging in the nets 25 206, 208. This way, all solar units 202 can be pointed continuously towards the moving sun. The nets 206, 208 can be sized to any scale or amount of solar units 202 arranged.

The side-wires forming the edges of the nets 206, 208 are a suspension cable 238 suspended in a substantially 30 parabolic shape, to obtain a homogeneous force distribution across the centre-part of the nets 206, 208, similar like the principle of a suspension bridge. This enables to hang the nets 206, 208 with the least amount of deflection.

21

The centre-part of the nets is repetitive in structure. The wires that connect to a solar unit 202 converge and diverge again towards the next solar unit 202, thereby forming a row 212 comprising an array of rhombuses 5 214. Every solar unit 202 is arranged to both upper and lower net 206, 208 in a diamond-shaped / rhomboidal fashion.

Each diamond / rhombus comprises two rhombus-corners 216 substantially oriented in the direction of the row 212, and two rhombus-corners 218 substantially 10 transverse to the direction of the row 212 (figure 13). The rhombus-corners 218 form the attachment points for the solar units 202.

The rhombus-corners 216 are connected to the wires 224 using a bearing construction according to the invention 15 that comprises intertwined portions (figure 13), thereby forming a web structure in the plane of the net 206, 208. Said web structure couples different rows 212. It furthermore allows a greater pre-tensioning to be applied to the net structure, thereby reducing sagging of the net 20 structure.

Although they show preferred embodiments of the invention, the above described embodiments are intended only to illustrate the invention and not to limit in any way the scope of the invention. It is particularly noted that the 25 skilled person can combine technical measures of the different embodiments. The scope of the invention is therefore defined solely by the following claims.

22

Various aspects of the invention are defined in the following clauses: 1. Bearing construction for a tracking system, 5 especially for an orbital tracking system such as a solar tracking system (100), said bearing construction (1) comprising: - an attachment member (8), that is configured for engagement with a tracking element (101) of said tracking 10 system; - wherein the attachment member (8) is arranged on at least two cords (2) that are attachable between at least two opposite attachment locations (111) of said tracking system; 15 - wherein said cords (2) comprise at least two intertwined portions (4a, 4b) that are twined in the same coiling direction and that are aligned along a joined rotation axis (10); and - wherein the attachment member (8) is arranged 20 between two associated adjacent intertwined portions (4a, 4b) .

2. Bearing construction according to clause 1, further comprising: 25 - an untwined portion (6a, 6b) directly adjacent each intertwined portion (4a, 4b); and - wherein said cords of said untwined portion (6a, 6b) diverge away from each other in the direction extending from their adjacent intertwined portion (4a, 4b).

30 3. Bearing construction according to clause 1 or 2, wherein both untwined portions (6a, 6b) that are associated with two neighboring intertwined portions (4a, 23 4b) are directed towards each other, and wherein the attachment member (8) is arranged between said untwined portions (6a, 6b).

5 4. Bearing construction according to any of the foregoing clauses, wherein the intertwined portions (4a, 4b) comprise at least a number of turns identical to the required number of rotations of 180° of the attachment member (8), and wherein one turn is defined as one rotation 10 of 180° around the rotation axis (10) that is jointly defined by two aligned intertwined portions (4a, 4b).

5. Bearing construction according to any of the foregoing clauses, wherein the attachment member (8) is 15 arranged on a continuous part of the cords (2).

6. Bearing construction according to clause 5, wherein the attachment member (8) is slidably arranged on the cords (2).

20 7. Bearing construction according to any of the foregoing clauses, wherein the intertwined portions (4a, 4b) and untwined portions (6a, 6b) comprise at least three cords (2) .

25 8. Tracking system, especially an orbital tracking system such as a solar tracking system, said tracking system comprising: - a plurality of tracking elements (101); 30 - suspension means (104) for suspending the plurality of tracking elements (101), said suspension means comprising a net (105); 24 - drive means (110), comprising connecting members (109) interconnecting a series of tracking elements such that said interconnected series of tracking elements (101) is simultaneously adjustable via the drive means (110); 5 - wherein the suspension means (104) comprise attachment locations (102) to which the tracking elements (101) are attachable; and - wherein the net (105) of the suspension means (104) comprises wires (124) that form the attachment 10 locations (102) to which the tracking elements (101) are arranged via a bearing construction (1) according to any of clauses 1-7.

9. Tracking system according to clause 8, wherein 15 every tracking element (101) is only connected to one single net (105) .

10. Tracking system according to clause 8 or 9, wherein the tracking elements (101) are arranged in a grid, 20 and wherein a plurality of tracking elements arranged in a row or column of the grid are driveably connected via the drive means (110) .

11. Tracking system, especially an orbital 25 tracking system such as a solar tracking system, said tracking system comprising: - a plurality of tracking elements (201); - suspension means (204) for suspending the plurality of tracking elements, said suspension means 30 comprising a first net (206) and a second net (208) oriented parallel in a plane, a distance existing therebetween; - wherein at least two drive means (210) are arranged to the suspension means (204) such that the first 25 and second net (206, 208) are moveable relative to each other in the plane by the drive means (210); - rotation limiting means (213) configured to limit a rotation of one or more tracking elements (201) with 5 respect to the suspension means (204); - wherein every tracking element (201) is arranged to both the first and second net (206, 208) such that the orientation of the tracking elements (201) is adjustable via the drive means (210) driving the suspension means (204); 10 and - wherein wires (224) of the nets (206, 208) of the suspension means (204) form attachment locations (211) to which the tracking elements (201) are arranged via a bearing construction (1) according to any of clauses 1-7.

15 12. Tracking system (100) according to clause 11, wherein the attachment locations (211) are wires (224) of the first net (206) and second net (208) of the suspension means (204), and wherein at least two cords (2) are 20 connected to a wire (224) of the first net (206) and at least two cords (2) are connected to a wire (224) of the second net (208) .

13. Tracking system (100, 200) according to any of 25 clauses 8-12, wherein a series of associated tracking elements (101, 201) is arranged on the tracking system with one or more bearing constructions (1) that comprise intertwined portions (4a, 4b) with the same coiling direction.

30 14. Tracking system (100, 200) according to any of clauses 8-13, wherein the attachment member (8) is an integrated part of the tracking element (101).

26 15. Tracking system according to any of clauses 8-14, being a solar tracking system (100, 200), wherein the attachment member (8) is configured to receive a solar unit 5 (102, 202) as tracking element (101, 102) .

Claims

A bearing construction for a web tracking system, in particular for a sun tracking system (100), the bearing construction (1) comprising: - a fastening member (8), which is adapted to engage with a follower element (101) of the tracking system; - wherein the fixing member (8) is arranged on at least two cords (2) that are attachable between at least two opposite mounting locations (111) of the tracking system; - wherein the cords (2) comprise at least two wound parts (4a, 4b) which are wound in the same winding direction and which are aligned along a common axis of rotation (10); and - wherein the fixing member (8) is arranged between two adjacent adjacent wound parts (4a, 4b). 20

Bearing structure according to claim 1, further comprising: - an unwound part (6a, 6b) that is directly adjacent to each wound part (4a, 4b); and 25. wherein the cords of the unwrapped portion (6a, 6b) move away from each other in the direction extending from an adjacent wound portion (4a, 4b).

3. Bearing construction as claimed in claim 1 or 2, wherein the two non-wound parts (6a, 6b) belonging to two adjacent wound parts (4a, 4b) face each other, and wherein the fastening member (8) is arranged between the non-wound parts (6a, 6b).

Bearing construction according to one of the preceding claims, wherein the wound parts (4a, 4b) comprise at least a number of turns that are identical to the required number of rotations of 180 ° of the fastening member (8), and wherein one turn is defined as one 180 ° rotation about the axis of rotation (10) that is jointly defined by the two aligned wound portions (4a, 4b). 10

Bearing construction according to one of the preceding claims, in which the fixing member (8) is arranged on a continuous part of the cords (2).

Bearing construction according to claim 5, wherein the fixing member (8) is slidably mounted on the cords (2).

7. Bearing construction according to one of the preceding claims, wherein the wound parts (4a, 4b) and the unwound parts (6a, 6b) comprise at least three cords (2).

8. Tracking system, in particular a web tracking system such as a sun tracking system, the tracking system comprising: - a number of follower elements (101); - suspension means (104) for suspending therein the number of follower elements (101), wherein the suspension means comprise a net (105); - drive means (110), comprising connecting members (109) which connect a series of follower elements to each other such that the connected series of follower elements (101) can be adjusted simultaneously via the drive means (110); - wherein the suspension means (104) comprise mounting locations (102) to which the follower elements 5 (102) can be attached; and - wherein the net (105) of the suspension means (104) comprises wires (124) which are the fixing locations (102) to which the follower elements (101) are arranged via a bearing construction (1) according to one of claims 1-7, 10 to shape.

The tracking system of claim 8, wherein each follower element (101) is connected to only a single net (105). 15

10. Tracking system according to claim 8 or 9, wherein the follower elements (101) are arranged in a grid, and wherein a number of follower elements arranged in a row or column of the grid are drivably connected via the drive means (110).

A tracking system, in particular a web tracking system such as a sun tracking system, the tracking system comprising: 25. a plurality of tracking elements (201); - suspension means (204) for suspending therein a number of follower elements, wherein the suspension means comprise a first net (206) and a second net (208) arranged parallel in a plane with a distance between them; - wherein at least two drive means (210) are arranged on the suspension means (204) such that the first and second net (206, 208) are movable in the plane relative to each other with the aid of the drive means (210); - rotation-limiting means (213) adapted to limit the rotation of one or more follower elements (201) relative to the suspension means (204); - wherein each follower element (201) is arranged on both the first and the second net (206), (208) such that the orientation of the follower elements (201) is adjustable via the drive means (210) that the suspension means (204) drive; and - wherein wires (224) of the nets (206, 208) of the suspension means (204) form attachment locations (211) to which the follower elements (201) are arranged via a bearing structure (1) according to any of claims 1-7. 15

The tracking system (100) of claim 11, wherein the mounting locations (211) are wires (224) of the first net (206) and second net (208) of the suspension means (204), and wherein at least two cords (2) are connected to a wire (224) of the first net (206) and at least two cords (2) are connected to a wire (224) of the second net (208).

13. Tracking system (100, 200) as claimed in any of the claims 8-12, wherein a series of associated follower elements (101, 201) with one or more bearing constructions (1), said wound parts (4a, 4b) with the same winding direction on the tracking system.

The tracking system (100, 200) according to any of claims 8-13, wherein the mounting member (8) forms an integral part of the follower (101).

A tracking system according to any of claims 8-14, which is a solar tracking system (100, 200), wherein the mounting member (8) is adapted to receive a solar unit (102, 202) as a follower (101, 202) .