MODULES MOUNTABLE ON TORQUE TUBES IN SOLAR

TRACKERS”

Field of the invention:

The present invention relates to flexible positioning and locking system for solar modules mountable on torque tubes of solar trackers, and more particularly to the flexible locking system for solar modules mountable on torque tubes with a shaped feature defined along the torque tube.

Background of the invention:

With the increase in the per capita consumption of energy, alternative sources of energy are most sought after as reliable and pollution free sources of energy. Solar energy is a renewable form of energy derived from the sun. The technology involves conversion of radiant energy from the sun into electrical energy through photovoltaic panels or similar devices. There are various technologies involved in the capture of light from the sun and converting it into electricity for further use. Maximum yield of solar energy can be obtained through maximum exposure of the photovoltaic panels or similar energy capturing apparatus to the radiant energy.

In order to maximize the light energy captured, modem solar panels mounting systems are designed to align with the direction of sunlight by orienting the structures in the direction of the sunlight. Thus, maximum sunlight is captured throughout the 10-12 hours of daylight further enabling efficient electricity generation. The system known as solar trackers position the solar panels or photovoltaic device at such an angle with respect to the position of the sun so that the sun’s rays fall at the lowest possible angle with respect to the normal of the panel. Accordingly, the trackers adjust the position of the solar panels throughout the day corresponding to the position of the sun.

The US patent application US2013037082A1 by Grant Thomas describes a solar tracker with a base, a first shaft, a second shaft and an automatic connection/disconnection device for varying the inclination of the solar panel with respect to the base. The US patent application US20180254740A1 to Corio Ronald P discloses a solar tracker assembly with a support column, torque tube, mounting mechanism, drive assembly and spring counterbalance assembly. The spring counter-balance assembly is used for improving the balance of the rotation of the solar arrays resulting in less torsional deflection of the solar assembly.

The US Patent US11035591B2 to Childress Isac Riley Joseph describes a bearing assembly for solar tracker having a rotating element sandwiched between two mounting brackets and held together by fasteners. The rotating element has an arc-shaped slot such that the rotating element can pivot against the fixed mounting brackets.

Thus, the torque tubes known in the art provide a flat resting surface for the solar modules. Torque tubes of various shapes including square, hexagonal, octagonal, or D-shaped are known in the art. It is observed that a round shaped torque tube leads to lesser thickness and is stronger in torsion. However, a solar module mounted on a rounded torque tube is more likely to have rotational motion relative to the longitudinal axis of the torque tube due to slippage as compared with torque tube of other shapes. Hence the solar modules are locked and fastened to the torque tube by a locking arrangement.

To address this problem, round torque tubes with hole-based locking were introduced in the prior art. Such torque tubes have predefined holes at predefined positions along the length of the torque tube. The said holes do generally receive fastening by means of projections to lock the relative motion between the torque tube and the solar module. This arrangement of holes and projections that are received in the holes enable proper locking of the solar module with the round torque tube.

However, it is noted that these holes are only obtained by drilling the torque tubes at predefined locations. In practice it is very much likely that the holes of the torque tubes don’t match with the locations of the projections in the solar module locking arrangement. The mismatch is likely to be on account of change of the solar module mid-project or due to issues in fabrication or installation of the torque tubes.

It is very difficult to maintain the alignment of the solar modules by locating a hole and inserting the projections in the holes when such a hole is little offset specially in huge structures of a solar tracking system. There are other problems associated with hole-based locking system like slipping of the module clamp, especially if locking assembly is not done properly. A change in the solar module type and/or module make and/or module size is a possibility during the construction of the solar plant and is one of the biggest challenges in this industry. There is a need of a flexible positioning system for fastening of solar module to torque tubes of solar trackers. There is also a need of flexible locking system for fastening of the solar module to the torque tube that locks the solar module on the torque tube irrespective of the location of the locking system.

Brief description of the drawings:

The objectives and advantages of the present invention will become apparent from the following description read in accordance with the accompanying drawings wherein:

FIG. 1 shows a perspective view of a flexible positioning and locking system for solar modules mountable on torque tubes in solar trackers in accordance with an embodiment of the present invention;

FIG. 2 shows a perspective view of a torque tube including a slot along length of the torque tube of the flexible positioning locking system of FIG. 1;

FIG. 3 shows an enlarged cross-sectional view of slot of the torque tube of FIG. 2; FIG. 4 shows a perspective view of a connector with U-bolt for securely positioning the top hat section on the torque tube of the flexible locking system of FIG. 1;

FIG. 5 shows a perspective view of another embodiment of the flexible locking system of FIG. 1;

FIG. 6 shows a cross sectional view of the torque tube of the system of FIG. 5;

FIG. 7 shows an enlarged cross-sectional view of step of the torque tube of the flexible locking system of FIG. 5; FIG. 8A shows an exploded perspective view of the second connector of the flexible locking system of FIG. 5;

FIG. 8B shows an assembled perspective view of a second connector of the flexible locking system of FIG. 5;

FIGS. 9 A and 9B show another embodiment of the flexible locking system of FIG.

5 including a pair of opposed steps and opposed connectors; and

FIGS. 10 is a perspective view showing a preferred method of connecting any two torque tubes of the flexible locking system of FIG. 5; and

FIG. 11 is a perspective view showing an assembly of two torque tubes of the flexible locking system of FIG. 5.

Summary of the invention:

A flexible positioning and locking system for solar modules on torque tubes used in solar trackers 500 is disclosed. The flexible positioning and locking system includes a step, and a second connector that connects the torque tube with a top hat that supports the solar module. Accordingly, the step defines a ridge along length of a torque tube 504 of the solar tracker. The second connector connects the torque tube 504 with a top hat 520. The connector has depression that slidably receives the step of the torque tube that defines a first torsional lock that constrains a relative rotational motion between the torque tube 504 and the connector 512. In accordance with the present invention, a plurality of torque tubes 504/504’ are connected with each other to define a composite torque tube structure of required length without any inappropriate orientation while connecting any two adjacent torque tubes 504/504’. The composite torque tube of predefined length includes a plurality of torque tubes 504/504’ that are advantageously connected with each other without any inappropriate orientation while connecting any two adjacent torque tubes. The system includes a second longitudinal lock that is defined by the second connector and the U-bolt. The second lock constraints longitudinal movement of the connector relative to the torque tube by selectively tightening the U-bolt. The step includes a head, a first link a second link, a first leg and a second leg, the links and that is angularly connected with respective legs and supporting the head. The depression of the second connector being movable in longitudinal direction for positioning the second connector on the torque tube. It is noted that the radius of the head of the step is approximately equal to a radius of the torque tube that facilitates rotational motion of the respective torque tube. The torque tube includes a first end and a second end such that the first swaged end includes a smaller step relative to the step of the second end. The torque tube includes a pair of opposed steps, a second connector and a third connector such that the second connector and the third connectors are approximately identical in shape and being opposedly positioned such that the each of the steps are positoinable in the respective depression of the opposed pair of second and third connectors that define the torsional lock. The torque tube includes a slot that runs along the length of the of the torque tube. The slot includes a first hem, a first under cut, a base, a second under cut, and a second hem. The first connector is a planar body including approximately centrally positioned projection, and a pair of housings. Detailed description of the drawings:

The invention described herein is explained using specific exemplary details for better understanding. However, the invention disclosed can be worked on by a person skilled in the art without the use of these specific details.

References in the specification to "one embodiment" or "an embodiment" means that feature, structure, characteristic, or function described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment.

References in the specification to “preferred embodiment” means that a particular feature, structure, characteristic or function described in detail thereby omitting known constructions and functions for clear description of the present invention.

The foregoing description of specific embodiments of the present invention has been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching.

Referring to FIG. l, a flexible positioning and locking system for solar modules mountable on torque tubes in solar trackers 100 is shown. Accordingly, the flexible positioning and locking system for solar modules mountable on torque tubes of solar trackers 100, hereinafter, referred as locking system 100 includes a torque tube 104 with a longitudinal slot 108, and a first connector 112. The first connector 112 connects the torque tube 104 to the solar module 116.

The first connector 112 connects the torque tube 104 with a top hat 120 that is fixedly connected with the solar module 116. It is, however, noted that the solar module 116 is securely connected with the top hat 120 preferably by fasteners like clamps, nut-bolts etc., known in the art. In accordance with the present invention, the torque tube 104 is connected to the top hat 120 with the connector 112 that includes a U-bolt 124

It is appreciated that the top hat 120 is component that is generally used in solar panel mounting systems. The top hat 120 includes a steel profile that is shaped like a hat, hence it is referred to as a top hat or hat section. In solar structures, the hats 120 are used as beams and purlins to provide support for solar panels and other components. The flat top of the top hat 120 section imparts a stable surface for attaching solar panels and the vertical sides offer rigidity and strength to the structure.

The torque tube 104 preferably has circular cross section and the torque tube 104 advantageously includes the deep drawn slot 108 that is defined on the circumferential portion of the torque tube 104 and preferably along the length of the torque tube 104. In accordance with the present invention, the first connector 112 has a projection 128 that is receivable in the slot 108.

The slot 108 is a shaped feature such as a channel defined in the torque tube 104 that advantageously receives the projection 128 while that is insertably positioned in the slot 108. Slot 108 and the projection 128 combiningly advantageously define a torsion lock that constrains motion of the solar module 116 relative to the torque tube 104. It is noted that slot 108 of the torque tube is preferably made by roll forming process that is known in the prior art. Projection 128 is movable for adjusting the position of the first connector 112 in the slot 108.

Now referring to FIG. 2 and 3, the torque tube 104 in accordance with the present invention is described. The torque tube 104 includes slot 108 that runs along the length of the of the torque tube 104 as indicated by axis- X. The slot 108 includes a first hem 200, a first under cut 204, a base 208, a second under cut 212, and a second hem 216. The slot 108 also includes a pair of opposed links 212A and 212B. The opposed links 212 A and 212B are connected to respective hems 200, 216. The links 212A and 212B are further connected with the torque tube 104. It is noted that the slot 108 including the first hem 200, the first under cut 204, the base 208, the second under cut 212, and the second hem 216 defines a shaped feature that imparts advantageously flexibility of positioning the solar module 116 on the torque tube 104.

As shown in FIG. 4, the first connector 112 is a planar body including an approximately centrally positioned projection 128, and a pair of housings 400 and 404. The U-bolt 124 has two opposed arms 408, 412 that are received in housings 400, 404 of the first connector 112, and that the torque tube 104 is tightly securely positioned in the U-shaped portion of the U-bolt 124. The opposed arms have nuts 406 to hold the top hat 120 with connector 112 on the torque tube 104 supported in the U-shaped portion of the U-bolt 124, together. The projection 128 of the connector 112 is advantageously positioned at a desired location in the slot 108 of the torque tube 104 and the nuts 406 on the U bolt arms 408 and 412 are tightened. Accordingly, the first connector 112 and thereby the solar module 116 is securely positioned at a desired location both torsionally and longitudinally on the torque tube 104.

As shown in FIG. 5, another embodiment of a flexible positioning and locking system for solar modules mountable on torque tubes in solar trackers 500, hereinafter, referred to as locking system 500 is described. Accordingly, the locking system 500 includes a torque tube 504, a step 508, and a second connector 512. The torque tube 504 preferably has a circular cross section, however, it may have other cross-sections like elliptical, semicircular etc. Step 508 runs along the length of the torque tube 504. The second connector 512 connects the torque tube 504 with a top hat 520 that is fixedly connected with the solar module (Ref. FIG. 1).

The step 508 is a longitudinal construction that is a bulge defined along the circumference of the torque tube 504 and that runs along the length of the torque tube 504. The step 504 is preferably made by tube manufacturing processes such as roll forming or the like. The torque tube 504 is connected to the top hat 520 with the second connector 512 that includes a U-bolt 524.

The second connector 512 includes a depression 528 that advantageously slidably receives the step 508. The step 508 is insertably positionable in the depression 528 of the second connector 512. In accordance with the present invention, step 508 and the depression 528 combiningly advantageously define a torsional lock that constrains motion of the solar module relative to the torque tube 504. The depression 528 of the second connector 512 is movable in longitudinal direction for positioning the second connector 512 on the torque tube 504 and also while securely frictionally positioning the second connector 512 on torque tube 504 by the U bolt 524 and nuts.

Now referring to FIGS. 6 and 7, the torque tube 504 includes the step 508 i.e. a ridge defined long the length of the torque tube 504. The step 508 includes a head 700, a first link 702A, a second link 702B, a first leg 704 and a second leg 708. The head 700 has a top portion that has an arcuate shape. The top portion is supported by links 702A and 702B that are angularly connected with respective legs 704 and 708.

The top portion of the head 508 has an arcuate shape such that the radius of the top portion i.e. radius R2 of the head 700 of step 508 is approximately equal to the radius R1 of the torque tube 504. R1 indicates radius of the torque tube 504 and R2 indicates a radius of the head 700 of step 508 relative to the center of the torque tube 504. It is noted that a circle defined by the radius R2 of the arcuate head 700 of step 508 is approximately identical to a circle defined by radius R1 of the torque tube 504. The head 700, links 702A, 702B and legs 704, 708 defining the step 508 impart flexibility of positioning the solar module on the torque tube 504.

In this one embodiment, the width of the head is approximately 40 mm, the length of each of the legs 704, 708 is approximately 24 mm. Further, the angle between the leg 708 and the head is approximately in the range of (90°to 120°), similarly an angle between the leg 704 and the head is approximately in the range of (90°to 120°). In this embodiment, the diameter of the torque tube is 139 mm approximately. Also, a circumscribing circle with radius Rlof the torque tube 508 has diameter of approximately 139 mm. This is because a portion of the torque tube 504 is within the circumscribing circle having radius Rl.

As shown in FIGS. 8 A and 8B, the second connector 512 includes a channel 800 and a washer plate 804. Channel 800 has a deeper U-shaped cross section. The washer plate 804 has a C-shaped cross section. For example, in one embodiment, the channel 800 is around 100mm deep, where as the C-shaped cross section of washer plate 804 is 15mm deep. The channel 800 includes a top 808 and a pair of opposed side walls 812. The washer plate 804 is positioned over the top 808 of the channel 800 with a U-bolt 816 such that the top hat 520 is sandwiched between washer plate 804 and the channel 800 thereby securely holding the torque tube 504. The U- bolt 816 is removably attachable with the connector 512 by positioning arms of U-bolt 816 in the through holes of the washer plate 804 and the channel 800.

Referring to FIGS. 9A and 9B, another embodiment 900 of the flexible locking system of FIG. 5 is shown. Accordingly, in this one embodiment, the torque tube 904 includes an opposed pair of steps 908, a second connector 912 and a third connector 914. The second connector 912 and the third connectors 914 are approximately identical in shape and are opposedly positioned such that the each of the steps 908 is positionable in the respective depression 928 of the opposed pair of second and third connectors 912, 914. As a result, in this embodiment a torsional lock of higher capacity is formed.

The connectors 912 are securely connected with the top hat 920 with a pair of opposed studs or threaded rods 932. It is understood, however, that a second connector is positioned in close proximity with the top hat 920 and is secured with the top hat 920 by bolts 932 and a washer plate 936 arrangement. The top hat 920 is sandwiched between the second connector 912 and the washer plate 936.

Referring to FIGS. 10 and 11, a preferred method of assembly of two torque tubes 504 / 504’of the present invention is described. In accordance with the present invention, the torque tubes 504/504’ include a plurality of pairs of opposed through holes 1012 at each end. The opposed holes 1012 are preferably diametrically opposedly located on the respective ends of the torque tubes 504 / 504’. In the present invention, the first torque tube 504 has a first end 1000 i.e. a swaged end, and the second end 1000’ is regular end i.e. it is not swaged end. The second torque tube 504’ has a first end 1004 i.e. a swaged end, and the second end 1004’ is a regular end.

In the first torque tube 504, the first swaged end 1000 includes a step 508’ and the second end 1000’ includes a step 508. In the second torque tube 504’, the first swaged end 1004 includes a step 508’ and the second end 1004’ includes a step 508. The step 508’ of the first swaged end 1004 of the torque tube 504’ is slidably insertable in the second end 1000’ of the torque tube 504 in a direction indicated by arrow ‘A’. In this assembly, the step 508’ of the second torque tube 504’ is slidably received in the step 508 of the second end 1000’ of the first torque tube 504.

The step 508’ has smaller shape so as to slidably insertably fit in the step 508 of the second end 1000’ of the first torque tube 504. The assembled torque tubes 504 and 504’ are fixedly secured preferably positioning blind bolts 1008 in respective holes 1012. In accordance with the present invention, a composite torque tube is formed by securely connecting a plurality of collinear torque tubes 504/504’ of the present invention. In this one arrangement, the composite torque tube of predefined length is formed. For example, in one case, to achieve a total length of a uniform torque tube construction of steel material of 97 (Ninety seven) meters, 09 (nine) units of torque tubes, each of length 11.125 meters were used. In this one embodiment the length of the swaged end as well as the respective step 508’ of the torque tube 504 was 350 mm. The composite torque tube is formed without any inappropriate orientation of one or more torque tubes 504 / 504’ while connecting any two adjacent torque tubes 504 / 504’.

The first swaged end 1000 advantageously defines the outer diameter of the respective end which is smaller than the inner diameter of the torque tube 504 i.e. the inner diameter of the second end 1000’. It is noted that swaging is a plastic deformation process that enables reducing the cross section of a tubular section by forcing it into a specifically shaped die with a cross section smaller than the original cross section of the tubular section. The first end of the torque tube 504 is swaged by the swaging process. Each end of the torque tube 504 has two or more pairs of holes 1012 that are configured diametrically opposite to each other.

In a preferred method of the colinearly joining two torque tubes, in a first step the first swaged end 1004 of the second torque tube 504’ is inserted into the second (non-swaged) end 1000’ of the second torque tube 504. In a next step, the pairs of diametrically opposite holes 1012 on both the swaged ends 1004 of the second torque tube 504’ and the non-swaged end 1000’ of the first torque tube 504 are aligned with each other. In a third step, the blind bolts 1008 are inserted and fitted in the holes 1012 to fit the torque tubes 504 / 504’ securely to each other.

Due to the steps 508/508’ running along the length of both the first and the second torque tube 504, there is no possibility of one torque tube being inserted inverted into the other.

In the present invention, blind bolts 1008 are preferably used to fasten one torque tube 504 to another in a rapid manner relative to the existing systems. The increase in speed of fastening any two torque tubes 504/504’ of the present invention while employing a swaged connection, as per the present invention, instead of a spliced connection is at least 08 (eight) times with least possibility of error or defect of the orientation of the torque tube 504/504’. With the step 508/508’, larger tolerances in the length of the torque tube 504 are accommodated as the location of the swaged joint is less important.

It will be appreciated that in the prior art a splice joint is generally used to connect one traditional torque tube to another, which requires many bolts and is very time consuming to install. However, in accordance with system and method of the present invention, for defining the connection of the two torque tubes 504/504’ the amount of time required is substantially reduced, and that there is no likelihood of incorrect positioning/assembling or locating the torque tubes because of the presence of the step 508/508’ in the joint between two torque tubes. Further, in the prior art generally only round traditional torque tubes are connected to each other and there is a possibility of fitting one torque tube inverted with respect to the other amounting to an error in the installation. However, due to the advantageous torque tube with the step 508/508’ any such possibility of inappropriate assembly of any two torque tubes 504/504’ shall not arise.

The step 508 allows positive torsional locking between the torque tube 504 and the second connector 512, however at the same time, the said step 508 prevents accumulation of water due to its convex shape and thereby reduces the possibility of any corrosion or rusting.

In accordance with the present invention, the slot 108 in the torque tube 104 of the first embodiment and the step 508 of the torque tube 504 of the another embodiment advantageously allow fast manufacturing of the torque tubes 104/504 as compared to traditional manufacturing of locating and making drilled holes in the traditional torque tubes. As a result, higher quantities of torque tubes 104/504 are shipped to the desired location. The cost of torque tube manufacture with longitudinal feature like a step 508 or slot 108 by roll forming is considerably lower than that of any other locking system known in the prior art.

The second connector 512 has a structure that advantageously maintains a predefined distance, whether higher or lower distance, between the torque and the rear surface of the solar module. The height of the opposed side walls 812 define the said distance. It is worthwhile to mention that in case of bi-facial solar modules that generate energy from both the front and the rear surfaces, such second connector 512 increases the gap between the bi-facial solar module and the torque tube 504 thereby reducing the direct shadowing on the rear surface of the bi-facial solar module. Also that, when the second connector 512 is employed, the energy generated by the bi-facial solar module is increased due to lower umbral shadowing of the rear surface due to the increased distance.

The foregoing description of specific embodiments of the present invention has been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching.

The embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, to thereby enable others, skilled in the art to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omission and substitutions of equivalents are contemplated as circumstance may suggest or render expedient, but such are intended to cover the application or implementation without departing from the scope of the present invention.