KEYING STRUCTURES

CLAIM OF PRIORITY

This application claims priority from each of the following United States Provisional Applications, hereby incorporated by reference: (1) Photovoltaic Panels Having Laterally

Extending Keying Structures Thereon, Application S.N. 61/088,412 filed 13 August 2008 (CL-4337);

(2) Solar Array Incorporating Photovoltaic Panels Having Laterally Extending Keying Structures Thereon, Application S.N. 61/088, 413, filed 13 August 2008 (CL- 4338) ;

(3) Method For Installing A Solar Array Incorporating Photovoltaic Panels Having Laterally Extending Keying Structures Thereon, Application S.N. 61/088,416, filed 13 August 2008 (CL-4339) ;

(4) Photovoltaic Panel Having Keying Structures With Snap Engagement Features, Application S.N. 61/182,348 filed 29 May 2009 (CL-4653);

(5) Photovoltaic Panel Having Keying Structures With Horizontally Resilient Snap Engagement Features,

Application S.N. 61/182,355 filed 29 May 2009 (CL- 4654) ;

(6) Photovoltaic Panel Having Keying Structures With Pivotally Mounted Snap Engagement Features, Application S.N. 61/182,439 filed 29 May 2009 (CL- 4655) ; (7) Photovoltaic Panel Having Keying Structures With Vertically Resilient Snap Engagement Features, Application S.N. 61/182,391 filed 29 May 2009 (CL- 4656) ; (8) Photovoltaic Panel Having Modularized Frame With Registration Features, Application S.N. 61/182,416 filed 29 May 2009 (CL-4657); and

(9) Method For Mounting A Photovoltaic Array Having Photovoltaic Panels With Snap Engagement Features, Application S.N. 61/182,427, filed 29 May 2009 (CL-4700) .

CROSS REFERENCE TO RELATED APPLICATIONS Subject matter disclosed herein is disclosed and claimed in the following copending applications, all filed contemporaneously herewith and all assigned to the assignee of the present invention:

Photovoltaic Panel Having Keying Structures (CL- 4337PCT) , (cognate of CL-4337PRV, CL-4653PRV through CL- 4657PRV) ;

Method For Installing A Solar Array Incorporating Photovoltaic Panels Having Keying Structures (CL-4339PCT; (cognate of CL-4339PRV, CL-4700PRV) ; and

Photovoltaic Panel Having Snap Engagement Features (CL-4653PCT) , (cognate of CL-4653PRV through CL-4656PRV) .

BACKGROUND OF THE INVENTION

Field of the Invention This invention relates to a photovoltaic panel that has laterally extending keying structures disposed thereon, to a photovoltaic array formed from a plurality of such panels, and to a method for forming the photovoltaic array from such panels . Description of the Art The potential of solar energy as a clean, renewable energy source is well documented. However, a substantial impediment to the more widespread use of solar energy, especially in residential applications, is the significant cost of installation of an array of photovoltaic panels. A significant fraction of the cost of a typical homeowner' s conversion to solar energy is related to the labor necessary to mount the photovoltaic panels to a support structure (e.g., a roof or a framework) .

Accordingly, it is believed to be advantageous to provide a photovoltaic panel having structural features that facilitate the mechanical and electrical interconnection of adjacent panels in a solar array to each other, thereby reducing installation cost.

SUMMARY OF THE INVENTION

The present invention is directed toward a photovoltaic panel that includes keying structures whereby the panel may be interconnected in a keyed manner with at least one other similarly configured panel to form a photovoltaic array. The keying structures insure that adjacent panels are mechanically arranged in a predetermined relative orientation and are electrically interconnected in a specific desired manner.

The panel includes a photovoltaic module from which keying structures in the form of first and second keying flanges extend laterally. The panel may include a frame that engages the module, with the keying flanges extending from the frame. Each keying flange has a mating surface defined thereon. The keying flanges are disposed on the panel such that the mating surfaces are arranged in a complimentary confrontational relationship with respect to each other . An electrode of a first polarity is mounted on the mating surface of the first keying flange and an electrode of a second polarity is mounted on the mating surface of the second keying flange. The electrodes are electrically connected to the photovoltaic cells included in the photovoltaic module .

Owing to the complimentary confrontational relationship between the mating surfaces on the keying flanges a direct electrical interconnection between electrodes on adjacent panels in a photovoltaic array may be effected by disposing a first flange on a first panel in a physically overlapping relationship with a second flange on an adjacent panel. The panel may further include a latching structure that enables adjacent panels in an array to be joined together with a snapping engagement. The latching structure is mounted to the keying flanges provided on the panels. One keying flange is provided with a latching feature while the other keying flange has a latching recess formed therein. The latching recess has an axis extending therethrough. The flanges are positioned on a panel such that movement of the mating surface on the one flange of one panel into mating engagement with the mating surface on the other flange of another panel causes the latching feature to deflect into snapping engagement with the latching recess.

In one embodiment the latching feature is connected to its keying flange through a resilient bridge. Relative movement of the panels into mating engagement causes the latching feature to flex along an axis of flexure defined in the resilient bridge and snap into engagement with the latching recess on the other keying flange of the second panel. Preferably, the axis of flexure and the axis through the latching recess are each oriented substantially parallel the radiation collection surface of the photovoltaic panel. More preferably, these axes are parallel to the mating surface on the respective flange on which the latching feature or the latching recess is disposed.

In another embodiment the latching feature is carried on a latching bar that is pivotally mounted on the one keying flange. A biasing element (e.g., a spring) biases the latching bar to a first position relative to the one keying flange. Relative movement of the panels into mating engagement causes the latching bar on the one flange of the first panel to pivot about a pivot axis against the bias of the biasing element into snapping engagement with the latching recess on the other keying flange of the second panel. Again, the pivot axis and the axis through the latching recess are each preferably oriented substantially parallel to the radiation collection surface of the photovoltaic panel and, in the more preferred instance, parallel to the mating surfaces on the flanges on which the latching bar or the latching recess are disposed.

In yet another embodiment the latching feature is disposed on a latching arm on one flange of one panel, the arm being able to flex along an axis of flexure oriented substantially perpendicular to the radiation collection surface of the photovoltaic panel. When the panels are moved together the arm flexes into snapping engagement with the latching recess on the other keying flange of the second panel. The axis of the latching recess is also preferably oriented substantially perpendicular to the radiation collection surface of the photovoltaic panel. More preferably, both the axis of flexure and the axis of the recess are also substantially perpendicular to the mating surfaces on the flanges on which they are disposed.

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In another aspect the present invention is directed to a photovoltaic array comprising a framework having a plurality of photovoltaic panels secured thereon. Each panel includes a photovoltaic module having a first and a second keying structure extending laterally therefrom. The photovoltaic panels are arranged such that the first keying structure of a first photovoltaic panel physically overlaps in abutting relationship with the mating surface of a second keying structure of a second, adjacent, photovoltaic panel. In such a disposition the electrodes on the respective keying structures are in electrically conductive contact whereby an electrical interconnection between electrodes on the adjacent panels in an array of photovoltaic panels may be effected. The panels may include the snap engagement latching structures described.

The framework may be formed of framework elements having electrical conductors disposed therein. In such a case the framework may includes one framework element that has a keying step having an electrode thereon. The first flange on the first panel of the array overlaps with the step, thereby disposing the electrode on the flange into electrical contact with the electrode on the step. The framework includes at least one additional framework element also provided with an electrode on its support surface. The second flange on another panel of the array overlaps the support surface on the additional framework element to dispose the electrode on the second flange and on the additional framework element into electrical contact. To facilitate array maintenance and system commissioning, the electrode structure also contains a test point accessible for the connection of test equipment when the panel is configured as part of a photovoltaic array.

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In yet other aspect the present invention is directed to a method for forming an array of such photovoltaic panels. The method includes the steps of:

(a) forming a support framework;

(b) placing a first panel on the framework elements such that the first and second keying structures of the first panel respectively overlay the first and second framework elements;

(c) placing the first keying structure of a second panel in overlapping relationship with the second keying structure on the first panel;

(d) securing the first panel to the first framework element whereby an electrical interconnection is effected between the electrode on the first panel and the electrode on the first framework element.

If the framework has electrical conductors therewithin and a surface electrode the method further includes the step of: securing one of the panels to the framework element whereby the electrode on one of the panels is disposed in electrically conductive contact with the electrode on the framework element, and thereby, in electrical connection with the electrical conductors carried within the framework.

If the panels include the latching structure described the method includes moving the panels relative to each other such that the mating surfaces on the panels are disposed in confrontational relationship. The movement of the mating surfaces on the panels into mating engagement causes the latching feature on a flange on one panel to deflect into snapping engagement with a latching recess on a keying flange of a second panel.

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In still another aspect the present invention is directed to the frame comprised of various interconnected modularized elements. The frame comprises four corner pieces, at least one linear piece disposed along each side of the frame, and a terminal block within each of two opposed sides of the frame. Each of the terminal blocks has a keying flange thereon. One of the terminal blocks has a keying flange with a latching feature thereon while the other terminal block has a keying flange with a latching recess thereon. The corner pieces, the linear pieces and the terminal blocks are able to be interconnected together to form a unitized frame structure disposed around the periphery of the module.

Each frame piece has a slot formed therein. When the frame pieces are interconnected together the slots in the frame pieces register with each other to form a peripheral channel that grasps the edges of module. Each corner piece is a right-angled member having a first and a second lateral surface thereon. The lateral surfaces of the corner pieces are oriented substantially perpendicular to the radiation collection surface of the module. The first lateral surface of each corner piece has a registration boss thereon while the second lateral surface of each corner piece has a registration cavity formed therein. The bosses and the cavities are arranged such that the registration boss on one corner piece and the registration cavity on another corner piece are presented along any side of the frame. When the first and second panels are snapped into engagement the registration boss on one corner piece of the first panel is received within a registration cavity on a corner piece of the second panel.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be more fully understood from the following detailed description taken in connection with the accompanying Figures, which form a part of this application and in which:

Figure IA is a stylized view of a photovoltaic panel having a frame in accordance with the present invention from the perspective of a terminal block having a first keying flange, the block being disposed along one side of the frame;

Figure IB is a stylized view of the photovoltaic panel of Figure IA from the perspective of a terminal block having a second keying flange disposed on the opposed side of the frame, the view being taken along view lines IB-IB in Figure IA;

Figure 1C is an exploded view of the photovoltaic panel generally similar to that shown in Figures IA and IB illustrating the various frame pieces comprising the frame; Figure 2A is a stylized perspective view generally similar to Figure IA showing a photovoltaic panel with the terminal blocks having the keying flanges thereon arranged along the shorter sides of the frame; Figure 2B is a stylized perspective view similar to Figure 2A showing a photovoltaic panel with one terminal block disposed along a shorter side of the frame and the other terminal block disposed along a longer side of the frame; Figure 3A is an enlarged perspective view of the first terminal block having the first keying flange of the frame;

Figure 3B is a side elevation view entirely in section taken along section lines 3B-3B in Figure 3A;

Figure 3C is a bottom view taken along section lines 3C-3C in Figure 3B;

Figure 4A is an enlarged perspective view of the second terminal block having the second keying flange of the frame;

Figure 4B is a side elevation view entirely in section taken along section lines 4B-4B in Figure 4A;

Figure 4C is a perspective view of the section of the second terminal block shown in Figure 4B; Figures 5A through 5C are diagrammatic side elevation views illustrating the snapping engagement of the latching feature on the first keying flange of a first panel into the latching recess on the second keying flange of a second panel as mating surfaces on the first and second panels are moved relative to each other into mating engagement;

Figure 6 is a perspective view showing the first and second terminal blocks and the keying flanges thereon in accordance with an alternate embodiment of the present invention;

Figures 7A through 7C are diagrammatic side elevation views similar to Figures 5A through 5C illustrating the snapping engagement of the latching features on the first keying flanges of the first and second panels in accordance with the embodiment of the invention shown in Figure 6;

Figure 8 is a perspective view showing the first and second terminal blocks and the keying flanges thereon in accordance with yet another alternate embodiment of the present invention; Figures 9A through 9C are diagrammatic bottom views generally similar in principle to Figures 5A-5C and Figures 7A-7C illustrating the snapping engagement of the latching features on the first keying flanges of the first and second panels in accordance with the embodiment of the invention shown in Figure 8 ; Figures 1OA and 1OB are perspective views illustrating a photovoltaic array formed from three strings of photovoltaic panels mounted on a framework, the keying flanges on the panels being disposed along the shorter sides of each panel frame, the panels in the array of Figure 1OA being arranged in "landscape formation" in which the electrical interconnection path along each string is oriented along the "Y" axis of a reference coordinate system while the panels in the array of Figure 1OB are arranged in "portrait formation" in which the electrical interconnection path along each string is oriented along the "X" axis of the reference coordinate system; Figures 1OC and 1OD are perspective views illustrating a photovoltaic array formed from three strings of photovoltaic panels mounted on a framework, the keying flanges on the panels being disposed along the longer sides of each panel frame, the panels in the array of Figure 1OC being arranged in "landscape formation" in which the electrical interconnection path along each string is oriented along the "X" axis of a reference coordinate system while the panels in the array of Figure 1OD are arranged in "portrait formation" in which the electrical interconnection path along each string is oriented along the "Y" axis of the reference coordinate system;

Figure 11 is an elevation view taken along view lines 11-11 in each of Figures 1OA through 1OD showing the mounting of the panels in each string to a framework; Figure 12 is a side elevation view entirely in section showing the first keying flange of a first photovoltaic panel in a row of a photovoltaic array mounted to a first support framework element of the array, the support element having a keying step thereon; and

Figure 13 is a side elevation view entirely in section showing the second keying flange of the last photovoltaic panel in a row of a photovoltaic array mounted to the last support framework element of the array.

DETAILED DESCRIPTION OF THE INVENTION Throughout the following detailed description similar reference numerals refer to similar elements in all figures of the drawings. It should be understood that various details of the structure and operation of the present invention as shown in various Figures have been stylized in form, with some portions enlarged or exaggerated, all for convenience of illustration and ease of understanding.

With reference to the drawings, Figure IA is a stylized perspective view of a photovoltaic panel generally indicated by the reference character 10 in accordance with the present invention. Figure IB is a similar perspective view of the panel 10 taken along view lines IB-IB in Figure IA. The panel 10 comprises a photovoltaic module 12 that is surrounded by a frame generally indicated by the reference character 14. The module 12 is a four-sided, usually rectangular, laminated structure having opposed pairs of longer side edges 12L ¹ , 12L ² and respectively adjacent shorter side edges 12S ¹ , 12S ² . The major axis 1OA of the panel 10 extends in parallel to the longer side edges 12L ¹ , 12L ² of the module. The module can be implemented in square form, if desired. The photovoltaic module 12 includes a photovoltaic layer 12P (e.g., Figures 3B, 4B) having one or more electrically interconnected photovoltaic cells formed therein. The photovoltaic layer 12P is usually sandwiched between a bottom support sheet 12B and a transparent top covering sheet 12T. The outer surface of the bottom sheet 12B defines the lower surface of the module 12 while the outer surface of the transparent covering sheet 12T defines a generally planar radiation collection surface 12R for the module. Each photovoltaic cell is operative to generate an electric current in response to incident radiation falling upon the radiation collection surface 12R. Any suitable photovoltaic module 12 may be used in the panel 10. In a typical instance the string of interconnected photovoltaic cells within the module 12 terminates in electrical connection tabs generally indicated by the reference character 12E. As will be discussed the connection tabs 12E are used to electrically connect the photovoltaic cells within the module to points on the exterior of the module. One connection tab 12E _P has a positive electrical polarity while the other connection tab 12E _N has a negative electrical polarity.

The connection tabs 12E may emanate from the module 12 at any convenient location. In the usual case the tabs depend from the bottom surface of the module 12E near opposed edges of the module. In the module illustrated in Figure IA a set of four tabs (including the positive connection tab 12E _P and the negative connection tab 12E _N ) is disposed along the long edge 12L ¹ near one of the shorter edges (e.g., the edge 12S ² ) of the module. The negative tab 12E _N is connected by a lead 12L that extends through the interior of the module and emanates as an additional single negative tab 12E _N from the opposed long edge 12L ² , again near the edge 12S ² .

In the module illustrated in Figure 1C the tabs are shown as disposed substantially midway along the opposed long edges 12L ¹ and 12L ² of the module. The tabs may be located nearer to an end of the long edges if desired. Alternatively, the connection tabs can be arranged to lie along the opposed short edges 12L ¹ , 12S ² of the module, as shown in Figure 2A. As a further alternative the sets of connection tabs may be located on adjacent side edges of the module (Figure 2B) .

The frame 14 is a four-sided structure that corresponds in peripheral shape to the shape of the module 12. For use with a rectangular module the frame 14 exhibits opposed pairs of longer side edges 14L ¹ , 14L ² and respectively adjacent shorter side edges 14S ¹ , 14S ² (Figures IA, 2) . As best seen in Figure 1C, in the preferred instance the frame 14 in accordance with the present invention is a modularized structure implemented by interconnecting a plurality of frame pieces into the desired peripheral form. The frame pieces are generally indicated by reference characters with the numerical prefix "15". However, it should be understood that it lies within the contemplation of the present invention that the frame may be alternatively implemented in any other convenient fashion so long as the various structural and functional elements to be described (including the keying flanges and latching structures) are included in the frame structure. For example, the frame may be implemented using frame bars (with integral flanges and latching features) to define the opposed sides of the frame, with adjacent frame bars being connected at their ends. In general, in the embodiment illustrated in Figure 1C the frame 14 is assembled from four corner pieces 15C, at least one linear piece 15L disposed within each side of the frame, and a first and a second terminal block 15T ¹ , 15T ² , respectively. Since the terminal blocks 15T carry the electrical circuitry elements that permit adjacent panels in an array to be electrically interconnected with each other the terminal blocks 15T ¹ , 15T ² are located along the sides of the frame (i.e., between corner pieces 15C) in positions corresponding to the locations on the sides of the module 12 at which the connection tabs 12E are provided. The two linear pieces 12L connected on each end of each terminal block 15T serve to position the terminal blocks 15T ¹ , 15T ² in the desired position along each long side of the frame 14. Thus, in the embodiment illustrated in Figure IA the terminal blocks 15T ¹ , 15T ² are connected within the long sides 14L ¹ and 14L ² of the frame 14 near the shorter side 14S ² , in correspondence to the above-discussed location of the connection tabs 12E on the module 12 illustrated in Figure IA. Similarly, in the embodiment illustrated in Figure 1C the terminal blocks 15T ¹ , 15T ² are connected substantially midway along the long sides 14L ¹ and 14L ² of the frame 14. In the arrangement shown in Figure 2 the terminal blocks 15T ¹ , 15T ² are disposed along the short edges of the module, again in correspondence to the location of the connection tabs for the module there shown. Figure 2B illustrates an instance in which the terminal blocks are disposed along adjacent edges of the frame.

The frame pieces 15 may be interconnected with each other in any convenient fashion. In the embodiments illustrated the ends of the corner pieces and the terminal blocks are provided with extending male plugs 15P (shown at various convenient locations in Figure 1C) . The plugs are received into hollowed ends 15H provided in the adjoining linear frame pieces. When interconnected together the corner pieces 15C, the linear pieces 15L and the terminal blocks 15T cooperate to form a unitized support structure disposed around the periphery of the module 12.

Each frame piece 15 has a main body portion 15B (see, e.g., Figures 3C, 4C) with an upper surface 15U and a lower planar surface 15M thereon. Each frame piece includes a finger 15G that overlies the upper surface 15U of the body portion 15B of that frame piece. Each finger 15G is formed to extend toward the inward edge of the frame piece (i.e., the edge of the frame piece presented to the edge of the module 12 when the frame engages the same) . The upper surface 15U of the body 15B of the frame piece and the finger 15G cooperate to form a slot 15S that extends along the margin of the frame piece. The slots 15S in the frame pieces disposed along each side of the frame register with each other to form a peripheral channel that receives and grasps the edges of the module. A gasket 15K (Figures 3B, 4B) is provided between the module and each frame piece. As seen in Figure 1C each corner piece 15C is a right-angled member having a first and a second lateral surface 15F ¹ , 15F ² . The lateral surfaces 15F ¹ , 15F ² are oriented substantially perpendicular to the radiation incident surface 12R of the module 12. One lateral surface of each corner piece 15C carries a registration boss 15R while the second lateral surface of each corner piece is provided with a registration cavity 15V. The bosses 15R and cavities 15V on the corner pieces 15C are arranged such that the registration boss on one corner piece and the registration cavity on another corner piece are presented along each side of the frame.

Further structural details of the first terminal block 15T ¹ are illustrated in Figures 3A through 3C. The structure of the second terminal block 15T ² is shown in more detail in Figures 4A and 4B.

In addition to carrying the circuitry that facilitates electrical interconnection between panels each terminal block 15T ¹ , 15T ² includes complimentary latching structures generally indicated at the reference character 16 that facilitate the mechanical and electrical interconnection of adjacent panels into a photovoltaic array. In each embodiment of the invention to be described one of the terminal blocks 15, (e.g., the block 15T ¹ ) includes a male latching feature 16M (e.g., Figures 3A, 3B) while the other terminal block 15T ² is provided with a corresponding female latching recess 16R (e.g., Figures 4A, 4B) . The female latching recess 16R has a reference axis 16A extending therethrough. As will be developed relative movement between adjacent panels as the panels are brought together brings the terminal blocks 15T ¹ , 15T ² into contact with each other and causes the latching feature 16M on one terminal block 15T ¹ of one panel to deflect into snapping engagement with the latching recess 16R on the other terminal block 15T ² of another panel, thereby to secure adjacent panels mechanically and electrically to each other. This action is described in detail in connection with the various embodiments of the latching structure of the present invention shown in Figures 5A-5C, 7A-7C, and 9A- 9C.

Both the first and the second terminal blocks 15T ¹ , 15T ² are generally similar in structure. The main body portion 15B of each terminal block 15T has an electrical component compartment 17C formed therein. The upper end of the compartment 17C opens onto the upper surface 15U of the block.

The sizes of the compartment may differ between the terminal blocks in accordance with the number of electrical connections completed therein. Thus, in the specified arrangement here illustrated the compartment 17C in the terminal block 15T ¹ is sized to complete the various electrical connections from all four of the connection tabs 12E in the set of tabs depending from the module 12 along the side 12L ¹ thereof (Figures IA, 1C) . Thus, the block 15T ¹ serves the function formerly served by the separate junction box usually disposed on the lower surface of a module in the prior art. The lower end of the compartment 17C in the terminal block 15T ¹ is closed by a removable base plate 17P that forms part of the lower surface 15M of the block.

In the specific case under discussion the compartment 17C in the terminal block 15T ² is relatively smaller, since it is sized to complete the electrical connection from only the additional single connection tab 12E _N emanating from the side 12L ² of the module. The compartment 17C is hollowed in the body 15B of the terminal block 15T ² . A keying flange 28, 30 laterally projects from the main body portion 15B of each terminal block. Each keying flange 28, 30 has a respective planar mating surface 28A, 3OA. In the case of the first terminal block 15T ¹ (Figure 3B) the planar mating surface 28A communicates with a pocket 28P formed in the body of the block for a purpose to be discussed. The pocket 28P is closed at each axial end. By "laterally" it is meant that each keying flange 28, 30 extends from its associated terminal block in a direction that is generally perpendicular to the side of the module 12 and generally parallel to the plane of the radiation collection surface 12R.

In the case of the second terminal block 15T ² (Figure 4B) a projecting rib 3OR extends from the mating surface of the flange 30, also for a purpose to be described. The forward edge of the rib 3OR is beveled, as at 3OB. As will be seen the dispositions of the pocket 28P and the rib 3OR may be alternated, if desired, with the first terminal block 15T ¹ carrying the rib 3OR while the second terminal block 15T ² having the pocket 28P therein.

In the preferred arrangement illustrated the mating surfaces 28A, 30A are disposed parallel to the radiation collection surface 12R of the module 12. The mating surfaces 28A, 30A on the keying flanges 28, 30 are disposed in complimentary confrontational relationship with respect to each other. The term "complimentary confrontational relationship" means that the mating surface of one keying flange faces toward the radiation collection surface, while the mating surface on the other keying flange faces away from that radiation collection surface.

The expressions "faces toward" and "faces away from" (and similar terms) may be understood from Figures IA and IB. Assume a first unit reference vector U ¹ erected orthogonal to the mating surface 28A (Figure IA) and a second unit reference vector U ² erected orthogonal to the mating surface 30B (Figure IB) . The mating surface 28A may be said to "face toward" the radiation collection surface 12R because the vector U ¹ extends in a direction in which it intersects the plane of the radiation collection surface 12R. Similarly, the mating surface 30A may be said to "face away from" the radiation collection surface 12R because the vector U ² extends in a direction that does not intersect the plane of the radiation collection surface 12R. It should be understood that the mating surfaces 28A, 3OA may be oriented at any convenient inclination to the radiation collection surface 12R so long as these surfaces are in complimentary confrontation relationship with each other, as discussed. In practice, the mating surfaces 32A, 32B may be inclined at about sixty degrees, although inclinations up to about ninety degrees lie within the contemplation of the invention.

The mating surface 28A, 3OA of each keying flange 28, 30 has a primary electrode 34, 36 respectively mounted thereon. The exposed surface of each electrode 34, 36 is open to and is accessible from the respective mating surface 28A, 3OA of the flange 28, 30 on which it is mounted.

Any convenient mounting scheme for the electrodes 34, 36 may be used. For example, the primary electrodes 34, 36 may take the form of generally cylindrical members each received within a respective bore 4OA, 4OB provided in the material of the flange. As seen in Figure 3B the primary electrode 34 is resiliently urged by the bias of a spring 41 toward the mating surface 28A of the flange 28 in which it is mounted. An annular abutment surface 42 defined within the bore 4OA in the flange 28 engages an enlarged peripheral shoulder disposed on the electrode 34 to hold that electrode within the bore 4OA against the bias of the spring 41. The free end of the spring 41 acts against the base plate 17P of the terminal block 15T ¹ . The relative positions of the peripheral shoulder 34S on the electrode and the abutment surface 42 in the bore 4OA are selected such that the surface of the electrode 34 stands slightly proud of the surrounding mating surface 28A of the flange 28. An O-ring seal member 43S is disposed in a groove 28G formed on the mating surface 28A of the flange 28. A connection bore 34B is formed in the back surface of the electrode 34 for a purpose to be described.

The primary electrode 36 (Figure 4B) is held within its bore 4OB in the flange 30 by a cover plate 44 that is secured to the mating surface 3OA of the flange 30. The surface of the electrode 36 extends through an opening in the cover plate 44 so as to lie flush with the surface 3OA of the flange 30. It should be understood that either one of the primary electrodes 34, 36 may be spring biased in its bore, and that the seal member may be disposed on either of the mounting surfaces.

An ancillary electrode 50, 52 is held in the interior of each compartment 17C of each respective terminal block 15T ¹ , 15T ² . The exterior surface of each terminal block 15T ¹ , 15T ² has a respective threaded protuberance, or boss, 56 that overlies the respective ancillary electrode 50, 52. An access bore 50B, 52B (Figures 3B, 4B) extends through each boss 56 into communication with the respective ancillary electrode 50, 52, whereby that ancillary electrode may be connected to an electrical destination. Each access bore 50B, 52B may be closed by a respective removable insulating and sealing cap 60 (one of which is shown in Figure 4B) . The cap may be attached to its boss as by threading onto exterior threads provided on each boss 56 or by any other convenient method of attachment. Each primary electrode 34, 36 has a predetermined electrical polarity dependent upon the polarity of the tab 12E to which that primary electrode is connected.

Figure 3C is believed to best illustrate the electrical connections associated with the primary electrode 34 on the block 15T ¹ . As noted earlier the connection tabs 12E depending from the module 12 proximate to the block 15T ¹ project into the compartment 17C in that block. A plurality of connection terminals 17T ¹ through 17T ⁴ is mounted within the compartment 17C of the block 15T ¹ . Each terminal 17T is conveniently secured (as by gluing) to a mounting peg 17P formed in the block. The edges of each terminal 17T are downturned to define mounting ears 17E on the terminal.

Inside the block 15T ¹ one of the terminals 17T ¹ to 17T ⁴ is electrically connected to each respective connection tab 12E. The positive connection tab 12E _P is secured to the terminal 17T ¹ while the negative polarity connection tab 12E _N is connected to the terminal 17T ⁴ . The terminal is 17T ⁴ is connected to the lead 12L that conveys the negative output from the module to the additional connection tab emanating from near the opposite edge of the module (Figures IA, 1C) .

The other two tabs 12E in the set that emanate from intermediate connection points in the string of photovoltaic cells in the module are connected to the terminals 17T ² and 17T ³ , respectively. Protective bypass diodes 17D, mounted on confronting ears 17E of adjacent terminals, are connected electrically between adjacent tabs. A wire 34W connected into the bore 34B on the back end surface of the electrode 34 passes through an opening in the material of flange 28 into the compartment 17C. The wire 34W is affixed to the terminal 17T ¹ connected to the positive connection tab 12E _P . A conductive stamping 17S is secured to an ear of the terminal 17T ¹ . The stamping 17S extends about the interior of the compartment 17 in the terminal block 15T ¹ to effect an electrical connection between the positive connection tab 12E _P and the ancillary electrode 50. The electrical connections associated with the primary electrode 36 on the block 15T ² are believed best illustrated in Figures 4B and 4C. The additional negative connection tab 12E _N on the opposite side of the module projects into the compartment 17C in the block 15T ² . The additional negative connection tab 12E _N is secured to an extending shelf portion of a conductive stamping 17S ¹ that lies on the bottom of the compartment 17C formed inside the block 15T ² . The other end of the stamping is connected to a conductive lance 17L ¹ that itself extends along one sidewall of the compartment and connects to the ancillary electrode 52. A wire 36W extends from the lance 17L ¹ and is connected to the primary electrode 36. When the connections are completed each compartment is sealed to the back of the module.

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As will be more fully discussed herein a photovoltaic array is configured as a plurality of adjacent linear rows or columns of panels arranged in matrix form and mounted on a framework. Each linear row of the matrix includes a plurality of panels connected in electrical series. Having the mating surfaces of the keying flanges of the panels disposed in the complimentary confrontational relationship as hereinabove described insures that adjacent panels in a row or a column are arranged in the desired relative mechanical orientation and are thus able to be electrically interconnected in the specific desired manner .

The complimentary latching structures provided on respective first and second terminal blocks facilitate the mechanical and electrical interconnection of adjacent panels in the array. As illustrated in Figures 3A and 3B, in accordance with one embodiment of the invention the lower edge of the flange 28 on the first terminal block 15T ¹ is provided with a forwardly extending male latching feature 16M. The latching feature 16M takes the form of a hemispherical rod-like member having a contoured surface thereon. The rod-like latching feature 16M extends a convenient distance across the breadth of the keying flange 28. The latching feature 16M is connected to the flange 28 through a resilient bridge 28B and is thus able to flex along an axis of flexure 28F that is oriented substantially parallel to the radiation collection surface (and, thus, also parallel to the mating surface 28A of the flange 28) . With reference to Figures 4A and 4B the second terminal block 15T ² has the latching recess 16R therein. The recess 16R corresponds to the rounded contoured surface of the male latching feature 16M on the block 15T ¹ . The latching recess defines a camming lip 16L. The latching recess 16R extends across the second terminal block 15T ² for a distance at least coextensive with the distance that the latching feature 16M extends across the first terminal block 15T ¹ . The axis 16A of the recess is also oriented substantially parallel to the radiation collection surface 12R and to the mating surface 3OA of the flange 30.

The operation of the latching structures whereby similarly configured adjacent panels 10, 10 ¹ are engaged with each other may be understood from Figures 5A through 5C. In these Figures the terminal blocks 15T ¹ , 15T ² are depicted as solid members to more clearly illustrate the mechanical latching action to be described. Figure 5A shows two similarly configured adjacent panels 10, 10 ¹ being brought together. As illustrated by the arrow 62, as the panels are moved relative to each other the projecting rib 3OR on the flange 30 on the block 15T ² (of the panel 10 ¹ ) is laid onto the mating surface 28A of the flange 28 on the block 15T ¹ (of the panel 10) . The initial contact between the beveled leading edge of the projecting rib 3OR and the electrode 34 (in the block 15T ¹ ) depresses the electrode to facilitate the introduction of the rib 3OR into the pocket 28P. Introducing one panel (e.g., the panel 10 ¹ ) in a slightly inclined direction facilitates this action. The panel 10 ¹ swings in the direction of the arrow 64 as it advances toward the panel 10 in the direction of the arrow 62.

As the panels 10, 10 ¹ are brought closer in the direction of the arrow 66 (Figure 5B) the rib 30R more fully enters into the pocket 28P. In addition, the camming lip 16L defined along the edge of the latching recess 16R interferes against the latching feature 16M on the flange 28 of the terminal block 15T ¹ , as illustrated.

Continued relative mating motion between the panels causes the latching feature 16M on the flange 28 of the first panel 10 to deflect, as indicated by the arrow 68. The deflection is accommodated by flexure of the resilient bridge 28B along its axis of flexure 28F.

As the male latching feature 16M clears the lip 16L the latching feature 16M snaps into engagement with the latching recess on the second keying flange of the second panel (as suggested by the arrow 70,

Figure 5C) . The rib 30R is completely inserted into the pocket 28P and the surfaces 28A, 30A are brought into full mated relationship. The electrodes 34, 36 on these surfaces are thus placed in direct electrical contact. The full mated engagement of the keying flanges 28, 30 is shown in Figure 5C. Since the axis of flexure 28F and the axis 16A of the recess 16R are substantially parallel to the radiation collection surface 12R and to the mating surfaces 28A 3OA of the flanges 28, 30 the directions of the deflection and the resilient return of the latching feature 16M in accordance with this embodiment of the invention occur in a plane that is oriented substantially perpendicular to the collection surface 12R and the mating surfaces 28A, 3OA of Figures 5A through 5C. The flexibility of the latching feature is controlled by judicious selection of the thickness dimension of the bridge.

The snapping engagement of the latching feature 16M into the latching recess 16R locks the flanges 28, 30 and prevents the panels 10, 10 ¹ from being withdrawn one from the other in substantially horizontal directions. Simultaneously, full receipt of the rib 3OR into the pocket 28P restricts relative motion of the panels in substantially vertical directions (as viewed in the plane of Figures 5A through 5C) . Since the pocket 28P is closed at each axial end movement of the panels 10, 10 ¹ into and out of the plane of Figure 5C is also precluded. Relative motion between the panels 10, 10 ¹ is thus restricted along all three degrees of freedom.

Arranging panels 10, 10 ¹ such that the mating surface 28A on the first keying flange 30 of a first panel 10 is in complimentary confrontational relationship with the mating surface 30A on the second keying flange 30 of the second panel 10 ¹ insures that when the flanges are physically overlapped in the described abutting relationship the primary electrodes 32, 34 on the respective flanges 28, 30 are connected in proper electrical fashion.

-o-O-o- Figure 6 illustrates terminal blocks having keying flanges with latching features configured in accordance with an alternate embodiment of the present invention. Figures 7A through 7C are diagrammatic views similar to Figures 5A through 5C illustrating the snapping engagement of the latching features on the keying flanges of the first and second panels in accordance with the embodiment of the invention shown in Figure 6.

The structural arrangement of the keying flanges on the terminal blocks is modified in several aspects from the arrangement illustrated in Figures 3 through 5. In the arrangement shown in Figures 6 and 7 the latching recess 16R is disposed on the keying flange

28 of the terminal block 15T ¹ of the panel 10 while the male latching feature 16M (implemented in two sections 16M ¹ , 16M ² as will be discussed) is carried on the keying flange 30 of the terminal block 15T ² on the frame 14 of the panel 10 ¹ .

The terminal block 15T ¹ is also modified to exhibit an enlarged central porch 28H through which the bore 4OA for the primary electrode 34 of panel 10 extends. The presence of the enlarged central porch 28H interrupts the continuity of the latching recess 16R and subdivides it into first and second recess sections, thus necessitating the subdivision of the male latching feature 16M into the two sections 16M ¹ , 16M ² . In this embodiment the camming lip 16L along the leading edge of each recess sections is planar.

The male latching feature on each section 16M ¹ , 16M ² is carried on the forward end of a respective first and a second latch bar 16B ¹ , 16B ² . As seen in Figures 7A through 7C the bottom surface at each axial end of the terminal block 15T ² is hollowed, as at 16H, to accept the latch bars 16B ¹ , 16B ² . Each latch bar 16B ¹ , 16B ² is pivotally mounted on a pivot pin 16V. Each pivot pin 16V has an axis 16X therethrough. The axes 16X are collinear. The latch bars 16B ¹ , 16B ² are pivotally movable against the bias of a biasing element 16S (illustrated as a coil spring) received in an opening communicating with the hollow 16H. Any convenient alternative form of biasing element (such as a leaf spring, Belleville washer arrangement) may be used. In this arrangement each section of the male latching feature 16M is pyramidal in shape and the recess 16R is likewise configured. The force required to deflect the latching feature is controlled by the biasing spring.

The operation of this embodiment of the invention is similar to that shown in connection with Figures 5A through 5C. As the adjacent panels 10, 10 ¹ are moved relative to each other in the direction of the arrow 72 (Figure 7A) the beveled leading edge 3OB of the projecting rib 3OR on the flange 30 (of the panel 10 ¹ ) depresses the electrode 34 on the flange 28 as the rib 30 enters into the pocket 28P on the flange 28 (of the panel 10) .

As suggested in Figure 7A continued relative motion in the direction of the arrow 72 brings the forward edge of the male latching feature 16M on each latch bar 16B into contact with the planar camming lip 16L adjacent to the latching recess 16R. This interaction causes each latch bar 16B ¹ , 16B ² to deflect by pivoting in the direction of the arrow 74 about its pivot axis against the bias of its associated spring.

As they clear the camming lip in response to continued mating motion of the panels each of the male latching features 16M on the latch bars is returned by the action of its spring and enters into snapping engagement with the latching recess, as illustrated by the arrow 76. The full mated engagement of the parts is shown in Figure 7C.

Similar to the situation extant with the structures of Figures 5A through 5C, since the pivot axis 16A of each latch bar 16B is substantially parallel to the radiation collection surface 12R and to the mating surface 3OA of its flange 30 the deflection and resilient return of the latching features in accordance with this embodiment of the invention also occurs in a plane that is oriented generally perpendicular to these surfaces (i.e., in a plane substantially parallel to the plane of Figures 7A through 7C) .

With the latching features on the flanges received in snapping engagement and with the rib fully seated in the pocket the relative motion between the panels along all three degrees of freedom is restricted.

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Figure 8 illustrates terminal blocks having keying flanges with latching features configured in accordance with yet another alternate embodiment of the present invention. Figures 9A through 9C are diagrammatic views (taken from beneath the flanges) illustrating the snapping engagement of the latching features on the first keying flanges of the first and second panels in accordance with the embodiment of the invention shown in Figure 8.

The structural arrangement of the keying flanges on the terminal blocks of Figures 8 and 9 is modified in several respects from the arrangement illustrated in Figures 3 through 5 and Figures 6 and 7, again to illustrate the versatility of the latching arrangement in accordance with the present invention. Although the mating surfaces 28A, 3OA are in complimentary confrontational relationship with respect to each other, it is noted that in the embodiment shown in Figures 8 and 9 the orientation of the mating surfaces 28A, 3OA on the keying flanges 28, 30 is reversed from that illustrated in the other Figures. In these Figures the mating surface 28A on the flange 28 (on the terminal block 15T ¹ on the panel 10) faces away from the radiation collection surface 12R (i.e., a vector U ² erected on the surface 28A does not intersect with the collection surface 12R of the module on the panel 10 received by the terminal block 15T ¹ ) . Conversely, the mating surface 3OA (on the flange 30 on the terminal block 15T ² ) faces toward the radiation collection surface 12R (a vector U ¹ erected on the surface 30A does intersect with the collection surface 12R of the module on the panel 10 ¹ received by the terminal block 15T ² ) . It will also be noted that in the arrangement shown in Figures 8 and 9 the male latching features 16M are carried on the keying flange 28 of the terminal block 15T ¹ of the panel 10 while the latching recesses 16R are disposed on the keying flange 30 of the terminal block 15T ² of the panel 10 ¹ . In addition the projecting rib 28R is carried on the keying flange 28 of the terminal block 15T ¹ while the pocket 30P is disposed on the keying flange 30 of the terminal block 15T ² .

However, the primary modification effected by this embodiment of the invention relates to the orientation of the axis 16A of the latching recess 16R and the orientation of the axis of flexure 16F of the male latching features 16M with respect to the radiation collection surface 12R and the mating surfaces 28A, 30A of the flanges on which they are disposed. As seen from Figures 8 and 9A-9C the latching structure includes a pair arms extending forwardly from the terminal block terminal block 15T ¹ . Each arm is a generally planar plank-shaped member terminated by distended bulbous end. The bulbous end on the arm serves as the male latching feature 16M. The planar region of each arm is able to flex about an axis of flexure 16F that is also oriented substantially perpendicular to the radiation collection surface 12R and to the plane of the mating surface 28A of the flange 28. The flexibility of the arms may be controlled by judiciously selecting the thickness dimension of the planar region.

Corresponding latching recesses 16R are provided in the keying flange 30 of the other terminal block

15T ² on the frame. Generally speaking, these latching recesses 16R are substantially similar in form to the latching recess depicted in the embodiment of Figures 3 through 5, except that the reference axis 16A through each latching recess 16R is also oriented substantially perpendicular to the radiation collection surface 12R and to the mating surface 3OA on the keying flange 30.

The operation of the latching structures in accordance with this embodiment may be understood from Figures 9A through 9C taken from the underside of the keying flanges on the panels 10, 10 ¹ .

The adjacent panels 10, 10 ¹ are moved relative to each other in the direction of the arrow 80 (Figure 9A) until the camming lip 16L at the leading edge of each latching recess 16A contacts the bulbous male latching feature 16M at the outboard end of each latching arm. This interaction is suggested in Figure 9B . Interference between the camming lips and the bulbous male latching features causes each latch arm to deflect by flexing along its axis of flexure in the direction of the arrow 82.

As the bulbous male latching features 16M clear the camming lip 16L in response to continued mating motion of the panels each of the male latching features is returned by the resiliency of its arm and enters into snapping engagement with the latching recess, as illustrated by the arrow 84. In accordance with this embodiment of the invention the directions of the deflection and resilient return of the arms occur in a plane that is oriented substantially parallel to the plane of the radiation collection surface and to the mating surfaces of the flanges.

The full mated engagement of the parts is shown in Figure 9C.

The receipt of the male latching features in snapping engagement into the latching recesses prevents the panels from being withdrawn horizontally relative to each other. The seating of the rib on one of the flanges in the pocket on the other flange serves to restrict relative motion between the panels along the other two degrees of freedom.

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The frame pieces may be manufactured in any convenient manner. The terminal blocks and corner pieces are preferably injection molded from any suitable electrically non-conductive material. A suitable material is a glass-reinforced polyester resin such as the injection moldable glass-fiber reinforced polyethylene terephthalate (PET) resin sold by E.I. du Pont de Nemours and Company under the trademark RYNITE ^® . The linear pieces may be either injection molded or extruded from the same material. Should be understood that although the keying flanges and the latching structures in accordance with any embodiment of the present invention carried thereon have been described in connection with a frame formed from interconnected modularized frame pieces, it lies within the contemplation of the present invention that the latching structures may be provided on keying flanges disposed on a frame manufactured in any other manner. For example, the latching arrangement in accordance with any embodiment of the present invention may be used on a frame configured from interconnected elongated frame bars manufactured using an extrusion process with the keying flanges formed on the frame bars by a machining process.

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As mentioned earlier an array of photovoltaic panels is usually configured in matrix form comprised of adjacent linear rows or columns of panels supported on a framework. The framework is mounted to a support structure (e.g., a roof) . However, the actual arrangement of the panels in an array for a given installation is determined by various practical circumstances presented by that installation.

An installer usually seeks to maximize the extent of panel coverage over the available area while minimizing the use of expensive inverters and connectors. To meet this goal the installer must usually determine whether it is more advantageous for the support framework for the array to be positioned in a vertical orientation (e.g., toward the roof ridge) or a horizontal orientation (i.e., parallel to the roof ridge) . The installer must also determine whether the electrical interconnections between adjacent panels in any string should extend in a vertical or a horizontal direction. In accordance with the present invention panels may be configured that will enable an installer to realize that arrangement that most efficiently accommodates these various considerations.

Figures 1OA through 1OD illustrate various exemplary arrangements for photovoltaic arrays made possible using photovoltaic panels configured in accordance with the present invention. Each of these Figures includes a reference coordinate system for ease of explanation.

Figures 1OA and 1OB are perspective views illustrating a photovoltaic array formed from three strings of photovoltaic panels 10. The panels are mounted on a framework F that is itself mounted to a support structure, depicted as a residential roof R. In these Figures 1OA and 1OB the terminal blocks having the keying flanges thereon are disposed along the shorter sides of each panel frame. Figures 1OC and 1OD are similar perspective views, with the terminal blocks having the keying flanges thereon are disposed along the longer sides of each panel frame.

The support framework F in Figures 1OA and 1OD is arranged such that the rails of the support structure extend vertically (in the direction of the X-axis) toward the ridge of the roof R. In Figures 1OB and 1OC the elements of the support structure extend horizontally (in the direction of the Y-axis), parallel to the ridge of the roof R. Gaps G are defined between adjacent rows or columns of the array, as the case may be. The gaps G extend perpendicular to the direction of the framework elements. As seen from Figure 11 the gaps G accommodate double-sided mid-clamp anchors A _D that secure confronting edges of adjacent panels to the support framework F. Single-sided end-clamp anchors A _s are used to attach panels along the edge of the array to the framework. Suitable mid-clamps and end-clamps are available from Unirac, Inc., Albuquerque, New Mexico . For a given framework direction panels may be attached in either "landscape formation" or "portrait formation" .

Figure 1OA illustrates an array in which the elements of the framework F extend vertically and in which the panels are arranged in "landscape formation". In Figure 1OD the elements of the framework F also extend vertically, but the panels are arranged in "portrait formation". However, in each instance, owing to the positioning of the terminal blocks on the frames, the electrical interconnection path along each string is oriented along the "Y" axis of a reference coordinate system.

Analogously, Figures 1OB and 1OC illustrate arrays in which the elements of the framework F extend horizontally. In Figure 1OB the panels are arranged in "portrait formation" while in Figure 1OC the panels are arranged in "landscape formation". In both cases, however, the position of the terminal blocks on the frames allows the electrical interconnection path along each string to be oriented along the "X" axis of a reference coordinate system.

It should also be appreciated that the use of a panel in which the terminal blocks are positioned in the manner shown in Figure 2B imparts further flexibility. With terminal blocks disposed on adjacent (rather than opposed) sides of the frame, it is possible to connect a panel in one row or column to a panel in an adjacent row or column.

To install the array, the framework F is created on the support structure. Panels 10 configured to meet the particular needs of the installation are placed on the framework in the desired formation. Adjacent panels are then moved relative to each other such that the mating surfaces on the adjacent panels are disposed in confrontational relationship with the mating surface on the one flange of a first panel is mated against the mating surface on the second flange of the second panel. The electrodes on the mating surfaces are disposed in electrical contact. Depending upon the embodiment of the complimentary latching structure 16 disposed on the panels, as discussed in connection with Figures 5A through 5C, Figures 7A through 7C, or Figures 9A through 9C, the movement of the mating surfaces on the panels into mating engagement causes the latching feature on the one flange of the first panel to deflect into snapping engagement with the latching recess on the other keying flange of the second panel.

If the corner pieces of the panel frames are provided with registration bosses 15R and corresponding registration cavities 15V (Figure IA) , these features are also engaged by inserting the boss on the frame of the one panel into the cavity on frame of an adjacent panel.

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The complimentary confrontational relationship between the mating surfaces 28A, 3OB results in the flange 30 of a panel being vertically offset from the exterior surface of the other flange 28 of the panel 10. The magnitude of the vertical offset is determined by the thickness dimension of the flange 28. Thus, the use of a keying structure in accordance with the invention requires that the framework elements F that support the panels at the beginning and end of each row of the array must exhibit certain structural features that accommodate the vertical offset of the flange 30 of a panel.

A framework element having one such structural feature is shown in Figure 12. In Figure 12 the framework element F ¹ that supports the first panel 10 ¹ in any given row of panels (e.g., extending in either the X or Y directions across the various arrays shown in Figures 1OA through 10D) includes at least one keying step 176. The keying step 176 is positioned along and mounted to the framework element F ¹ such that the keying step 176 underlays the flange 30 of the first panel 10 ¹ in that row of the array. The keying step 176 may alternatively be attached to the panel. The keying step 76 has a thickness dimension 176T that is equal to the thickness dimension of the second flange 28 of the panel 10 ¹ . The keying step 176 is preferably a nonconductive member, fabricated from the same material as the framework elements. A suitable seal 163 may be provided to prevent the entry of moisture to the electrode 36.

The situation existing at the distal end of the same given row of the array is illustrated in Figure 13. The flange 28 of the panel 10 ^N (the last of the N panels in that row) directly overlays and is supported by last framework element F ^L of the array. Since the electrode 34 is exposed on the surface of the flange it is necessary to take suitable precautions against the possibility of unwanted electrical contact. To this end (and for aesthetic reasons) a cap piece 191 may be provided over the mating surface of the flange 28. The cap piece 191 is a nonconductive member, preferably fabricated from the same material as the framework elements. A seal 162 prevents the ingress of water along the interface between the mating surface 28A of the flange 28 and the undersurface of the cap piece 191. As illustrated both the step 176 (Figure 12) and the cap piece 191 (Figure 13) may carry a latching structure corresponding to the embodiment of the latching structure carried on the panels 10 ¹ and panel 10 ^N to facilitate attachment thereto.

It should be understood that various protective structures are required by relevant safety standards (e.g., Underwriters' Laboratory Standards UL-1703 or UL-486A) for considerations of personal safety. However, it should be understood that these protective structures have been omitted from the drawings for clarity of illustration. It may also be desirable that the panels forming the array include an accessible test point contact that facilitates array maintenance and system commissioning through which test equipment may be connected. Accordingly, as shown in Figure 12, a test point contact 175T is mounted at the base of a threaded counterbore 175B formed in the flange 30. The test contact 175T is connected by a conductor 175W to the electrode 36. The conductor 175W is diagrammatically illustrated in Figure 12. The counterbore 175B is closed by a weather-tight cap 175C.

The framework elements F ¹ and F ^N may carry internal electrical conductors for use in interconnecting the panels forming the array to various destination points (such as a series connection to an adjacent panel, a parallel connection to combined strings, or in the case of a panel having a dedicated AC inverter, to the AC distribution bus) . A framework element having such internal wiring is disclosed in Application PCT/US08/87890, filed December 22, 2008 and published July 9, 2009, assigned to the assignee of the present invention. If such framework elements are used to support the array it is necessary to connect the panels 10 ¹ and 10 ^N to the respective framework elements F ¹ and F ^N supporting the same. Such connections for the panels 10 ¹ and 10 ^N are respectively illustrated in Figures 12 and 13.

To facilitate these connections of the panel 10 ¹ (Figure 12) to a framework element that includes internal conductors the surface of the keying step 176 has an electrode 178 mounted thereon. The electrode 178 is connected to a conductor 184 whereby the panel 10 ¹ may be interconnected into the internal electrical wiring of the framework element whereby the panel may be connected as described above. The conductor 184 may take any convenient form and is conveniently routed through vias 186 in the step 176 and through a via 188 into the interior of the framework element F ¹ . The step 176 should be appropriately secured to the framework element F ¹ . To connect the last panel 10 ^N (Figure 13) to internal conductors disposed within the framework element F ^L an electrode 190 is provided in the surface S of framework element F ^L . A conductor 194 is connected to the electrode 190. The conductor 194 may be routed through via 198 into the interior of the framework element F ^L whereby the panel 10 ^N may be interconnected into the electrical wiring of the array or to an adjacent panel. A seal 166 prevents the ingress of water along the interface between the exterior surface 28B of the flange 28 and the surface S of the framework elements F ^N .

It is also necessary to modify the electrode arrangement 34 mounted on the flange 28 to effect an electrical contact with the electrode 190. To this end a carrier rod 154 is received with a sliding fit within an access bore 140 formed within the flange 28. The carrier rod 154 may be injection molded or insert molded from a suitable material such as polybutylene terephthalate (PBT) . The electrode 34 is mounted at the first end of the carrier rod 154. A secondary electrode 34' is mounted to the tapered second end of the carrier rod 154. The secondary electrode 34' is electrically connected to the primary electrode 34 by a conductor 34W (diagrammatically illustrated) . A biasing spring 157 is received around a spring guide 150 formed by a counterbore provided in the material of the flange 28. In the preferred instance the spring 157 is implemented using stacked Belleville spring washers. The spring 157 acts to bias the secondary electrode 34' toward the exterior surface 28B of the flange 28.

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Those skilled in the art, having the benefit of the teachings of the present invention as hereinabove set forth may effect numerous modifications thereto. Such modifications are to be construed as lying within the contemplation of the present invention as defined by the appended claims.