WO2012151671A1

WO2012151671A1 - Support arm assembly

Info

Publication number: WO2012151671A1
Application number: PCT/CA2012/000427
Authority: WO
Inventors: Sreedharan Venkataratnam; Michael M. Miller; Gianfranco Gabbianelli
Original assignee: Magna International Inc.
Priority date: 2011-05-10
Filing date: 2012-05-04
Publication date: 2012-11-15

Abstract

A solar panel assembly is provided including an array of reflective panels and a chassis assembly for supporting the array of reflective panels. The chassis assembly includes a plurality of support arms extending radially outwardly from a central hub. A plurality of brackets interconnect the support arms with the reflective panels. A plurality of the brackets are L-shaped brackets attached to an adjacent reflective panel at one point and a plurality of the brackets are J-shaped brackets attached to an adjacent reflective panel at two points. Each bracket includes an elongated slot, through which it is attached to one of the supporting arms. The elongated slot allows the same type of bracket to be used at various points along the support arm and to attach the same type of support arm to reflective panels having different curvatures.

Description

SUPPORT ARM ASSEMBLY

CROSS-REFERENCE TO PRIOR APPLICATION

[0001] This PCT patent application claims the benefit of U.S. Provisional Patent Application Serial No. 61 /484,404 filed May 10, 201 1 , entitled "Support Arm

Assembly," the entire disclosure of the application being considered part of the disclosure of this application and hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

[0002] The subject invention is related to a support arm assembly for supporting a solar array.

2. Description of the Prior Art

[0003] Renewable resources are becoming an increasingly popular alternative to non-renewable resources for generating electricity. One renewable resource that can be converted into electricity is solar energy. Solar power generators harness the potential energy of solar rays from the sun and convert that potential energy into electricity. One type of solar power generator utilizes focused solar rays to heat and boil a fluid. The heat in the fluid is then converted into electricity. A parabolic solar array is generally used to focus the solar rays.

[0004] The solar array is composed of a plurality of individual reflective panels, each of which must be precisely shaped to focus the solar rays. For maximum effectiveness, the solar array must remain outdoors, and therefore, it must be resistant to a wide range of environmental factors. Such environmental factors could include high winds, heavy rains, and rapid temperature changes. To resist these forces, solar arrays are generally supported by a chassis assembly having a plurality of support arms.

[0005] The amount of electricity produced by the solar power generator is proportional to the amount of solar rays harnessed. Therefore, such solar arrays are often very large in order to maximize the amount of solar rays collected and focused on the solar power generator. However, the large size often dictates that the solar array and chassis assembly must be assembled in the field rather than in a factory setting.

[0006] There is a significant and continuing need for improved support arms which can be cheaply manufactured, are resistant to environmental forces and can be efficiently assembled in the field.

SUMMARY OF THE INVENTION

[0007] One aspect of the present invention provides for an improved support arm for supporting a solar array of reflective panels. The support arm includes at least one arch arm which extends to a distal end and a bracket. The bracket has a first leg for attachment to the arch arm and a second leg for attachment to one of the reflective panels. At least one of the arch arm and the first leg of the bracket includes an elongated slot, and wherein the bracket is attachable to the arch arm at any point along the elongated slot. The elongated slot allows the brackets to be adjusted to various heights relative to the lower arch, thereby allowing the same support arm to be used to support solar arrays of different curvatures. Thus, cost savings can be realized through economies of scale by producing a single type of support arm for solar arrays having many different sizes and curvatures. [0008] According to another aspect of the present invention, the at least one arch arm is made of a metal sheet, such as steel or aluminum, and is shaped through a series of roll forming steps. The upper and lower arches may also be roll formed to define its curvature. The roll forming process is advantageous because it is a cost efficient process and the roll forming equipment can easily be adjusted to produce arch arms of varying lengths and curvatures. Thus, very few changes to the manufacturing equipment are required to change the length, width, and/or curvature of the arch arm being produced. As such, support arms having various configurations can be produced on the same machinery for little or no additional costs, thereby leading to cost savings.

[0009] According to yet another aspect of the present inv ention, rubber pads are disposed between the brackets and the reflective panels. At least some of the rubber pads are affixed to the reflective panels e.g.. with an adhesive, and at least some of the rubber pads are not affixed to the reflective panels to allow for movement of the panels relative to the rubber pads in response to thermal expansion or contraction between these parts. Thus, the risk of either of these components being damaged during temperature changes is reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Other advantages of the present invention will be readily appreciated, as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

[0011] Figure 1 is a perspective and elevation view of the exemplary embodiment of the solar array; [0012] Figure 2 is a perspective and elevation view of the chassis assembly of the exemplary embodiment;

[0013] Figure 3 is a perspective and elevation view of the solar array mounted on the chassis assembly;

[0014] Figure 4 is a side view of an exemplary embodiment of the support arm;

[0015] Figure 5 is a top and fragmentary view of the B-surface of the solar array with the exemplary embodiment of the support arm;

[0016] Figure 6 is a cross-sectional view of the exemplary embodiment of the support arm taken along line 6-6 of Figure 4;

[0017] Figure 7 is another side view of the exemplary embodiment of the support arm supporting a reflective panel having a parabolic curve;

[0018] Figure 8 is a side view of the exemplary embodiment of the support arm supporting a reflective panel having a parabolic curve different than the parabolic curve of the reflector panel of Figure 7;

[0019] Figure 9 is a bottom elevation view of the solar array mounted on the exemplary chassis assembly;

[0020] Figure 10 is a perspective and fragmentary view of a plurality of exemplary support arms mounted on a solar array; and

[0021] Figure 1 1 is a perspective view of an exemplary J-shaped bracket.

DETAILED DESCRIPTION OF THE ENABLING EMBODIMENTS

[0022] Referring to the Figures, wherein like numerals indicate corresponding parts throughout the several views, an exemplary solar array 20 is generally shown in Figure 1. The solar array 20 of the exemplary embodiment includes a plurality of individual panels 22 arranged relative to one another to present a dish-like shape for focusing solar rays, as is common in the art. As shown in Figure 9, the panels 22 of the exemplary embodiment are not all of uniform shape. For example, the exemplary panels 22, adjacent the center of the dish are wedge shaped, whereas the panels along the circumference of the solar array assembly 20 (perimeter of the dish) are generally rectangularly shaped. Each of the panels 22 includes an A-surface, or upper surface, for supporting a reflective member and a B-surface, or lower surface, opposite the A- surface. The reflective members are preferably mirrors but could alternately be any other type of structure capable of reflecting light. Each of the panels 22 follows a parabolic curve to focus reflected sunlight onto a focal point.

[0023] The solar array 20 is preferably mounted outdoors to maximize the amount of sun exposure it receives. As such, it must be resistant to a wide range of environmental forces and conditions common in a range of operating environments. Some of those environmental forces and conditions could include strong winds, heavy rain, rapid temperature changes, heavy snow accumulations, etc. To resist these forces and conditions, the solar array 20 is mounted on a rigid chassis assembly 24. The exemplary chassis assembly 24 is generally shown in Figure 2 and includes a central hub 26 and a plurality of support arms 28 extending radially outwardly from the central hub 26. Each of the support arms 28 extends through an arc to present a concave center area for receiving the solar array assembly 20 described above. In the exemplary embodiment, the support arms 28 are disposed on opposite edges of the wedge-shaped reflective panels 22 such that the wedge-shaped reflective panels 22 are supported by two support arms 28 (one on each side). As discussed above, the exemplary solar array assembly 20 includes a greater number of generally rectangular panels 22 along its circumference. Referring now to Figure 9 and discussed in further detail below, the generally rectangular reflective panels 22 along the circumference of the solar array assembly 20 are each supported by a single support arm 28.

[0024] Referring now to Figures 2 and 3, a mounting bracket 30 is fastened to the central hub 26, and a boom arm 32 extends axially from the mounting bracket 30. A solar beam collector 34, which is configured to capture solar rays and converts them into electricity, is attached to the end of the boom arm 32. The boom arm 32 is sized such that the solar beam collector 34 is positioned at the focal point of the solar array 20 to maximize the amount of solar rays collected by the solar beam collector 34 during operation and thereby maximize the amount of electricity produced by the solar beam collector 34. The solar beam collector 34 could be, for example, a photovoltaic cell or a heat engine such as a steam turbine which converts heat generated by concentrated solar rays into electricity.

[0025] Figure 3 shows the exemplary solar array 20 of Figure 1 mounted onto the exemplary chassis assembly 24 of Figure 2. The solar array 20 includes a gap without reflective panels 22, which provides clearance for a mounting pole (not shown). The solar array 20 can thus articulate from a stowing position to a range of sun tracking positions. As such, the solar array 20 is able to "follow the sun" through the sky and optimize the amount of solar light reflected by the solar array 20 to the solar beam collector 34 throughout each day. Movement of the solar array 20 is controlled by a controller (not shown), as is common in the art. [0026] Referring now to Figure 4, one of the support arms 28 of the exemplary chassis assembly 24 is generally shown. The support arm 28 includes an upper arch arm 36 (upper arch), a lower arch arm 38 (lower arch) and a plurality of vertical braces 40 spaced from one another and interconnecting the upper and lower arches 36, 38. The upper and lower arches 36, 38 each extend from the central hub 26 and converge together at a distal end. In the exemplary embodiment, the vertical braces 40 are strategically spaced relative to one another to optimize the stiffness of the support arm 28. The upper and lower arches 36, 38 and the vertical braces 40 are preferably of metal, such as steel or aluminum. However, depending on the size, weight, strength, and cost requirements of the chassis assembly 24, the upper and lower arches 36, 38 could alternately be made of any other suitable material, including other metals, composites or polymeric materials.

[0027] In the exemplary embodiment, the lower arch 38 is attached to the B- surface of at least one reflective panel 22 through a plurality of L-shaped brackets 42 and a plurality of J-shaped brackets 44. However, it should be appreciated that the lower arch 38 could be alternately be connected to the reflective panels 22 with only L- shaped brackets 42 or only J-shaped brackets 44. The upper and lower arches 36, 38 are each curved to support the solar array 20, which preferably follows a second, third or fourth order parabolic curve. As will be discussed in greater detail below, the upper and lower arches 36, 38 could have a wide range of sizes and curvatures depending on the particular solar array 20 to be supported. In other words, the support arm 28 is scalable to accommodate solar arrays having a range of different sizes and shapes. [0028] In the exemplary embodiment, the upper arch 36 includes a pair of apertures (not shown) for receiving bolts (not shown) or other fasteners to attach the upper arch 36 to the central hub 26. Either the lower arch 38 or the central hub 26 includes a slot (not shown) and the other includes an aperture (not shown). One way to connect the support arm 28 to the central hub 26 is to first attach the upper arch 36 to the central hub 26 with the pair of bolts. Then, with the upper arch 36 connected to the central hub 26, another bolt is inserted through the slot and aperture of the central hub 26 and lower arch 38 to interconnect the central hub 26 and lower arch 38. This process may minimize internal stresses within the support arm 28. However, it should be appreciated that support arms 28 could be attached to the central hub 26 through a wide range of other connection mechanisms.

[0029] Referring now to the cross-sectional view of Figure 6, the upper arch 36 is shaped to present a generally rectangular opening with a pair of legs 48 extending downwardly therefrom and disposed adjacent to one another. Each of the vertical braces 40 is disposed between the legs 48 and is preferably spot welded to the upper arch 36. However, it should be appreciated that the vertical braces 40 could be attached to the upper arch 36 through any suitable type of connection, including for example, mechanical fasteners, adhesives, brazing, etc.

[0030] The lower arch 38 of the exemplary support arm 28 is generally I-shaped as viewed in cross-section and includes two halves 49a, 49b. Each half 49a, 49b presents a crown 51a, 51b, an upper flange 53a, 53b and a lower flange 55a, 55b. The crowns 51a, 51b of the two halves 49a, 49b are preferably spot welded to one another with the vertical braces 40 being sandwiched therebetween to interconnect these components. However, it should be appreciated that the halves 49a, 49b could be attached to one another and to the vertical braces 40 through any suitable connection.

[0031] In the exemplary embodiment, the cross-sectional shapes of the upper arch 36 and the lower arch halves 49a, 49b are shaped through a series of roll forming steps. The curvature of the upper arch 36 and lower arch halves 49a, 49b can also be formed by roll forming before, during or after the shaping of the cross-section of the respective component. The roll forming process is beneficial because, with simple adjustments in the roll forming equipment, the upper and lower arches 36, 38 can be formed to any desired length or curvature. Thus, the same machinery can quickly be adjusted to produce a wide range of support arms 28 for supporting a range of different solar arrays 20. This leads to reduced manufacturing costs and an ability to quickly adapt the roll forming machinery to produce support arms 28 for solar arrays 20 of different sizes and curvatures. However, it should be appreciated that any other forming process, such as extrusion, could alternatively be employed to produce the upper and lower arches 36, 38.

[0032] In the exemplary embodiment, at least one of the flanges 53a, 53b of each of the lower arch halves 49a, 49b presents a plurality of apertures (not shown) spaced from one another along the length of the lower arch 38. A weld nut 57 is attached to the flange 53a, 53b and aligned with each of the apertures. Either an L- shaped bracket 42 or a J-shaped bracket 44 is aligned with each of the apertures opposite of the weld nut 57 for interconnecting the support arm 28 and the reflective panel 22. [0033] Each L-shaped bracket 42 includes a first leg 50 and a second leg 52 extending at a right angle from, or generally perpendicularly to, the first leg 50.

Referring now to Figure 8, the first leg 50 of each L-shaped bracket 42 presents an elongated slot 46. Referring back to Figure 6, in the exemplary embodiment, a bolt 59 extends through the slot 46 of the L-shaped bracket 42 and threaded ly engages the aligned weld nut 57 of the adjacent lower arch 38 to connect the L-bracket 42 to the lower arch 38. The second leg 52 of each of the L-shaped brackets 42 is either connected to or abuts the B-surface of the reflective panels 22, as will be described in further detail below. It should be appreciated that the elongated slot 46 could alternately be on the lower arch 38 and that any suitable fastener could be employed to attach the L-shaped brackets 42 to the lower arch 38.

[0034] The bolt 59 can extend through any portion of the elongated slot 46, and thus, the same L-shaped bracket 42 may be used to attach reflective panels 22 having a wide range of curvatures to the lower arch 38. For example, Figure 7 shows a solar array 20 having a first curvature mounted on the support arm 28 of the exemplary embodiment, and Figure 8 shows a different solar array 120 mounted on the support arm 28, wherein the different solar array 120 has a second curvature which is different, i.e. flatter, than the first curvature of the solar array 20 shown in Figure 7. It should be appreciated that the L-shaped brackets 42 could be used to support a wide range of solar arrays, not just those shown in Figures 7 and 8. Thus, because the same L-shaped bracket 42 can be used for solar arrays 20 having different curvatures, manufacturing costs are reduced through economies of scale. [0035] As shown in Figures 9 and 10, some of the reflective panels 22 farthest from the central hub 26 are only supported by a single support arm 28. For additional strength, a J-shaped bracket 44, as opposed to an L-shaped bracket 52 - may be used to interconnect these reflective panels 22 with the support arm 28. As shown in Figure 1 1 , the J-shaped brackets 44 each have a first leg 58 presenting an elongated slot 60 similar to the elongated slot 46 of the L-shaped brackets 42 and a second leg 62 for mounting to the reflective panel 22. Unlike the L-shaped brackets 42, the J-shaped brackets 44 further include a third leg 64 which extends at an angle from the top of the first leg 58 downwardly to engage the adjacent reflective panel 22 at a location spaced from the second leg 62.

[0036] Referring back to Figure 4, a rubber pad 56 may be disposed between the

L-shaped brackets 42 (or the J-shaped brackets 44) and the reflective panel 22. The rubber pad 56 is preferably attached to the L-shaped and J-shaped brackets 42, 44 with an adhesive. The same or a different type of adhesive also adheres the rubber pads 56 to the reflective panels 22; however, it should be appreciated that any desirable attachment means could be employed to connect the rubber pads 56 to the brackets 42, 44 and/or the reflective panels 22. Additionally, not all of the rubber pads 56 need to be attached to the reflective panels 22. In some instances, it might be advantageous to have only a fraction of the rubber pads 56, e.g. every other rubber pad 56, attached to the reflective panels 22. The non-attached rubber pads 56 and their respective L-shaped or J-shaped brackets 42, 44 then act as guides to support the reflective panels 22 while allowing for thermal expansion or contraction of the reflective panels 22 and/or the support arms 28 while reducing the risk that either of these components will be damaged by the expansion.

[0037] The foregoing invention has been described in accordance with the relevant legal standards, thus the description is exemplary rather than limiting in nature. Variations and modifications to the disclosed embodiment may become apparent to those skilled in the art and fall within the scope of the invention.

Claims

CLAIMS In The Claims:

Claim 1. A support arm for supporting a panel of a solar array, comprising: at least one arch arm extending to a distal end;

at least one bracket including a first leg for attachment to said at least one arch arm and a second leg for attachment to the panel; and

at least one of said arch arm and said first leg of said bracket including an elongated slot, and wherein said bracket is attachable to said arch arm at any point along said elongated slot.

Claim 2. The support arm as set forth in claim 1 wherein said at least one bracket is an L-shaped bracket with said first and second legs extending generally perpendicularly to one another.

Claim 3. The support arm as set forth in claim 1 wherein said at least one bracket is a J-shaped bracket with said first and second legs extending generally perpendicularly to one another and further including a third leg for attachment to the panel at a location spaced from said second leg.

Claim 4. The support arm as set forth in claim 1 wherein said at least one bracket includes a plurality of L-shaped brackets with said first and second legs extending generally perpendicularly to one another and a plurality of J-shaped brackets with said first and second legs extending generally perpendicularly to one another and further including a third leg for attachment to the panel at a location spaced from said second leg.

Claim 5. The support arm as set forth in claim 4 wherein said plurality of brackets are spaced from one another long the length of said at least one arch arm.

Claim 6. A solar panel assembly, comprising:

an array of reflective panels;

a chassis assembly including a central hub and plurality of support arms for supporting said reflective panels;

each of said support arms including a plurality of arch arms extending radially outwardly from said central hub to distal ends;

at least one bracket including a first leg coupled with at least one of said arch arms and a second leg coupled to at least one of said reflective panels; and

at least one of said arch arm and said first leg of said bracket including an elongated slot, through which said bracket is coupled to said arch arm.

Claim 7. The solar panel assembly as set forth in claim 6 further including a pad disposed between said second leg of each of said brackets and said reflective panels.

Claim 8. The solar panel assembly as set forth in claim 7 wherein said pad is of a rubber material.

Claim 9. The solar panel assembly as set forth in claim 7 wherein at least one of said pads is fixed to the adjacent one of said reflective panels and wherein at least one of said pads is unfastened to the adjacent one of said reflective panels to allow for expansion and contraction of said support arm and said panel relative to one another.

Claim 10. The solar panel assembly as set forth in claim 9 wherein a plurality of said pads are fixed to the adjacent ones of said panels with an adhesive.

Claim 1 1. The solar panel assembly as set forth in claim 6 wherein said at least one bracket includes a plurality of L-shaped brackets with said first and second legs extending generally perpendicularly to one another and a plurality of J-shaped brackets with said first and second legs extending generally perpendicularly to one another and further including a third leg for attachment to the panel at a location spaced from said second leg.

Claim 12. The solar panel assembly as set forth in claim 1 1 wherein at least one L-shaped bracket is attached to each side of at least one of said reflective panels.

Claim 13. The solar panel assembly as set forth in claim 12 wherein at least one of said reflective panels is supported only by one of said J-shaped brackets.

Claim 14. The solar panel assembly as set forth in claim 6 further including a plurality of brackets spaced from one another along each of said support arms.

Claim 15. A method of forming a solar panel assembly, comprising the steps of: providing an array of reflective panels;

roll forming at least a portion of a support arm to a predetermined shape and a predetermined curvature;

providing a plurality of brackets each having a first leg with an elongated slot and a second leg; attaching the second leg of at least one of the brackets to at least one of the reflective panels; and

attaching at least one of the brackets to the support arm through the elongated slot.