WO2009086150A1

WO2009086150A1 - Soft-faced clamp for photovoltaic frameless modules and laminates

Info

Publication number: WO2009086150A1
Application number: PCT/US2008/087753
Authority: WO
Inventors: Jim Webb
Original assignee: Unirac, Inc.
Priority date: 2007-12-21
Filing date: 2008-12-19
Publication date: 2009-07-09

Abstract

A soft-faced clamp for securing frameless photovoltaic modules and laminates to each other and to a surface is provided herein. The clamp may be a mid-clamp securing two photovoltaic modules or an end-clamp securing a single photovoltaic module. The clamps include a top part, a bound elastomer for contacting the frameless module, and a base with extruded steps forming a ledge for securing the top part and elastomer and preventing excessive force from being applied to the photovoltaic module.

Description

SOFT-FACED CLAMP FOR PHOTOVOLTAIC FRAMELESS MODULES AND

LAMINATES

BACKGROUND

Most photovoltaic devices are framed devices called modules. The modules are held to a rooftop or pole or arrayed on the ground using various mounting devices including mounting rails, mounting clamps, nuts and bolts. The clamps are used to hold the framed modules to the rails. Photovoltaic devices without frames are called frameless modules or laminates. A method is needed to hold the frameless modules to the mounting rails.

Current products use molded elastomeric materials inserted into aluminum extrusions to provide a soft surface to contact the frameless module. During installation, the elastomeric material frequently separates from the aluminum extrusion requiring time-consuming reattachment.

In addition, current products do not provide a means of controlling the amount of force applied to the glass surfaces of frameless modules. This results in either insufficient force being applied, in which case the frameless module is not held to the rail adequately, or excessive force being applied, in which case the frameless module could be damaged.

Until recently, most modules were made from crystalline silicon and needed a frame for structural strength. Some manufacturers have developed crystalline silicon photovoltaic products which do not require frames. Now, thin film technologies have become commercially practical. These modules use two sheets of glass and no longer need the frame for structural strength. The thin film technologies promise lower module costs and, hence, are extremely attractive, but still require devices to hold them to the mounting rails with adjustable force and use an elastomeric material that does not separate from the clamping device during installation. SUMMARY OF THE INVENTION

Devices for securing frameless photovoltaic modules or laminates to mounting structures are provided herein. These clamping devices are suitable for using limited force in securing frameless modules and represent an improvement in the design of the elastomeric soft surface component or "soft face" which contacts the module. In the instant invention, the elastomeric component is securely bonded to the clamping device along one or more surfaces, preventing the elastomer from separating from the device during installation.

In a preferred embodiment of the invention, the clamping device disclosed herein is comprised of three basic elements: a clamp top with at least one elastomer which is used to make contact with the photovoltaic module or laminate without damaging the surface of said module, a clamp base, and a bolt and nut for passing through a bore in the clamp top and base to secure the assembly together and secure the clamp to a mounting structure, such as a rail. In this embodiment of the disclosed clamping device, the clamp top has a horizontal segment and two descending vertical segments spaced apart from one another and designed to provide a surface for securing the elastomer. The generally C-shaped elastomer therefore has two horizontal segments and a vertical segment. These segments may be part of a unitary elastomer, or may be manufactured as separate segments, for example an L-shaped elastomer comprising a horizontal segment and vertical segment, and a second elastomer comprising only a horizontal segment. Further, the elastomer may be designed as three separate segments: one vertical segment and two separate horizontal segments arranged into the same generally C-shaped structure described above.

In another preferred embodiment, the clamp base comprises a horizontal segment with two aluminum or other metallic extruded segments referred to as "steps" which together form a ledge capable of contacting the descending vertical segments of the clamp top and acting as a fixed-stop, thus limiting the force being applied onto the photovoltaic module or laminate to protect such modules from damage while maintaining them securely. In other embodiments, the clamp top or clamp base may be made of plastic or other similar materials. Another embodiment of the preferred invention is a clamping device wherein either the upper horizontal segment of the elastomer is bonded to the horizontal segment of the clamp top, the vertical segment of the elastomer is bonded to one of the descending vertical segments of the clamp top, or both the upper horizontal segment and the vertical segment of the elastomer are bonded to the horizontal segment and one of the descending vertical segments of the clamp top, respectively. It is contemplated that the bonding of the elastomer to the clamp top may be achieved using suitable liquid, paste, gel, or other adhesives or double-sided tapes or films. Such adhesive materials are well known to persons of ordinary skill in the art and are not described in further detail herein.

In another embodiment, the at least one elastomer of the clamping device may be bonded to the clamp base as an alternative to bonding it to the clamp top. In this embodiment, the lower horizontal segment of the elastomer is bonded to the horizontal segment of the clamp base.

In some embodiments of the claimed invention, the clamping device is a mid-clamp which secures photovoltaic modules on both sides of the clamp, using one elastomer to secure each of the two modules at the module or laminate's edge. In other embodiments disclosed herein, the claimed invention is an end-clamp, using only one elastomer to secure a single photovoltaic module or laminate.

In still another embodiment of the disclosed invention, the clamping device is secured to a mounting structure on a surface, such as a rail with a track to which the clamp may be fixed with a bolt and nut assembly used to assemble the clamping device. Such attachment to a mounting rail or other photovoltaic device mounting structure may take a wide variety of possible forms depending on the structure used, but the bolt used to assemble the clamping device is easily adapted by the person of ordinary skill in the art to fit the appropriate rail or alternative mounting structure to secure the clamping device and photovoltaic modules to said structure. It is further contemplated that instead of a conventional bolt and nut assembly, a similar part could be used to secure the clamp assembly to the rail. Such modifications are believed to be well within the skill of the person of ordinary skill in the art. In another contemplated embodiment of the disclosed invention, the elastomer could be molded to fit around the horizontal and one of the descending vertical segments, in whole or in part.

In yet another contemplated embodiment, the elastomer could be manufactured to grip and secure the photovoltaic module with finger-like or hollow closed shapes or protrusions commonly known to persons of ordinary skill for improving the security of the contact between the clamping device and the module. Such simple modifications in the design of the elastomer are considered within the scope of the disclosed invention.

An "elastomer" is a polymer material with the property of elasticity. The term, which is derived from elastic polymer, is often used interchangeably with the term rubber, but is not limited to that embodiment. Generally, each of the monomers which link to form the polymer is usually made of carbon, hydrogen, oxygen and/or silicon. Elastomers are typically amorphous polymers existing above their glass transition temperature, so that considerable segmental motion is possible. At ambient temperatures elastomers are thus relatively soft and deformable. Their primary uses are for seals, adhesives and molded flexible parts.

A durometer may be used to analyze the properties of the elastomer and select an elastomer, such as rubber, which best suits the need of the application. The durometer functions by analyzing a given substance, and then assigning it a number to denote the level of harness and durability. A lower number would indicate a softer nature for the substance, while a higher number would indicate the product is harder and less susceptible to bending or cracking. The durometer value of an elastomer can be varied for use with the disclosed clamping device to increase or decrease gripping strength on the frameless photovoltaic module or laminate.

In addition, the foregoing has outlined broadly the more important features of the invention to better understand the detailed description which follows, and to better understand the contribution of the present invention to the art. Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in application to the details of construction, and to the arrangements of the components, provided in the following description or drawing figures. The invention is capable of other embodiments, and of being practiced and carried out in various ways. Also, the phraseology and terminology employed in this disclosure are for purpose of description, and should not be regarded as limiting.

As those skilled in the art will appreciate, the conception on which this disclosure is based readily may be used as a basis for designing other structures, methods, and systems for carrying out the purposes of the present invention. The claims, therefore, include such equivalent constructions to the extent the equivalent constructions do not depart from the spirit and scope of the present invention. Further, the abstract associated with this disclosure is neither intended to define the invention, which is measured by the claims, nor intended to be limiting as to the scope of the invention in any way.

The novel features of this invention, and the invention itself, both as to structure and operation, are best understood from the accompanying drawings, considered in connection with the accompanying description of the drawings, in which similar reference characters refer to similar parts, and in which:

BRIEF DESCRIPTION OF THE FIGURES

FIG. IA is an illustration showing the assembled mid-clamp.

FIG. IB is an illustration showing a top view of the assembled mid-clamp.

FIG. 1C is an illustration showing side view of the assembled mid-clamp.

FIG. ID is an illustration showing an exploded- view of the mid-clamp assembly.

FIG. 2 A is an illustration showing the assembled end-clamp. FIG. 2B is an illustration showing a top view of the assembled end-clamp.

FIG. 2C is an illustration showing side view of the assembled end-clamp.

FIG. 2D is an illustration showing an exploded- view of the end-clamp assembly.

FIG. 3 is an illustration of an assembled mid-clamp oriented between two photovoltaic modules

FIG. 4 is an illustration showing the side view of an assembled end-clamp with the bolt securing the clamp in the track of mounting rail

FIG. 5 is an illustration of an end-clamp assembly securing the edge of a photovoltaic module and further securing the module to a mounting rail DETAILED DESCRIPTION OF THE INVENTION

FIGS. IA, IB, and 1C show the "mid-clamp" version of the assembled structure, including clamp top 1, elastomer 2, bolt 4 with washers 11 and nut 5 attached to the bottom of the assembly underneath clamp base 3, which provides steps 10a and 10b to constrain descending vertical parts 6a and 6b of the clamp top. This mid-clamp holds two laminates or frameless modules 12. Individual elements of the clamp assembly are best viewed in FIG. ID. Mid-clamp top 1 could be metallic or plastic and is shaped like the Greek letter "pi" consisting of a horizontal segment 8 and two vertical segments 6a and 6b. C-shaped elastomers 2 consist of two horizontal segments, 9a and 9b, and one vertical part 9c. Horizontal part 9a of elastomer 2 is bonded to horizontal segment 8 of mid-clamp top 1 using a suitable liquid, paste, gel or similar adhesive or a double-sided tape or film. Vertical segment 9c of elastomer 2 is similarly bonded to vertical part 6a or 6b of mid-clamp top 1. In one embodiment, bonded surfaces are 9a to 8, 9c to 6a or 6b, 9b to mid-clamp base 3. However, optional construction may bond only 9a to 8, 9b to 8, or 9C to 6a or 6b.

Vertical parts 6a and 6b engage with and are constrained by steps 10a and 10b forming ledge 7, formed in mid-clamp base 3, a second clamp part which also could be metallic or plastic. These steps 10a and 10b forming ledges 7a and 7b center mid-clamp top 1 over mid- clamp base 3 and constrain the vertical motion of mid-clamp top 1 toward base 3 during installation of bolt 4, washers 11 abutting both mid-clamp 1 and base 3, and nut 5. The constraint provided by steps 10a and 10b forming ledges 7a and 7b limits the force placed on the laminates or photovoltaic modules 12 placed between the horizontal surfaces of 9a and 9b of each elastomer 2.

FIGS. 2 A, 2B, and 2C show the "end-clamp" version of the assembled structure, including clamp top 13, elastomer 2, bolt 4 with washers 11 and nut 5 attached to the bottom of the assembly underneath clamp base 14, which provides steps 10a and 10b to constrain descending vertical parts 6a and 6b of the clamp top 13. This end-clamp holds two laminates or frameless modules 12 as seen in FIG. 2C. Individual elements of the clamp assembly are best viewed in FIG. ID. end-clamp top 13 could be metallic or plastic and is shaped like the Greek letter "pi" consisting of a horizontal segment 8 and two vertical segments 6a and 6b. C-shaped elastomers 2 consist of two horizontal segments, 9a and 9b, and one vertical part 9c. Horizontal part 9a of elastomer 2 is bonded to horizontal segment 8 of end-clamp top 13 using a suitable liquid, paste, gel or similar adhesive or a double-sided tape or film. Vertical segment 9c of elastomer 2 is similarly bonded to vertical part 6b of end-clamp top 13. In one embodiment, bonded surfaces are 9a to 8, 9c to 6b, 9b to end-clamp base 14. However, optional construction may bond only on of 9a to 8, 9b to 8, or 9C to 6b.

Vertical parts 6a and 6b engage with and are constrained by steps 10a and 10b forming ledge 7, formed in end-clamp base 14, a second clamp part which also could be metallic or plastic. These steps 10a and 10b forming ledges 7a and 7b center end-clamp top 13 over end- clamp base 14 and constrain the vertical motion of end-clamp top 13 toward base 14 during installation of bolt 4, washers 11 (abutting both end-clamp top 13 and base 14), and nut 5. The constraint provided by steps 10a and 10b forming ledges 7a and 7b limits the force placed on the laminates or photovoltaic modules 12 placed between the horizontal surfaces of 9a and 9b of each elastomer 2.

FIG. 3 shows a mid-clamp assembly including clamp top 1 oriented between and securing two photovoltaic modules 12 in each of two C-shaped elastomers 2, best seen in FIG. 1C.

FIG. 4 and FIG. 5 show an end-clamp assembly including end clamp top 13 and mounting rail 15, shown as an example of a mounting structure to which the clamping devices disclosed herein may be bound.

Claims

1. A clamping device for frameless photovoltaic modules or laminates comprising: a clamp top, a clamp base, and at least one elastomer, wherein the clamp top further comprises a horizontal segment and two descending vertical segments and further wherein the elastomer comprises two horizontal segments and one vertical segment, and secures the end of said frameless photovoltaic module between said segments

2. The clamping device of claim 1, wherein the clamp base further comprises a horizontal segment and two ascending steps forming a ledge capable of contacting the descending vertical segments of the clamp top and constraining the force applied by the clamp top on the frameless photovoltaic modules

3. The clamping device of claim 1, wherein one of said horizontal segments of the elastomer is bonded to the clamp top horizontal segment

4. The clamping device of claim 1, wherein said vertical segment of the elastomer is bonded to a clamp top descending vertical segment and further wherein said vertical segment of the elastomer is bonded to a clamp top descending vertical segment

5. The clamping device of claim 2, wherein one of said horizontal segments of the elastomer is bonded to said clamp base horizontal segment

6. The clamping device of claim 1, wherein the clamp top, clamp base, and at least one elastomer are fixed in position by a bolt passing through the clamp top, adjacent to said vertical segments of the at least one elastomer, and through the clamp base, where it adjustably secured with a nut

7. The clamping device of claim 1, wherein the clamp top and clamp base are metallic

8. The clamping device of claim 1, wherein the clamp top and clamp base are plastic

9. The clamping device of claim 1, wherein the clamp is a mid-clamp that secures the edges of two photovoltaic modules

10. The clamping device of claim 1, wherein the clamp is an end-clamp that secures the edge of no more than one photovoltaic module

11. The clamping device of claim 1, wherein the bolt further secures the clamp assembly to a structure for attaching said photovoltaic module or laminate to a surface

12. The clamping device of claim 11, wherein said structure is a rail attached to a surface

13. A clamping device for frame less photovoltaic modules or laminates comprising: a clamp top, a clamp base, and at least one elastomer, wherein the clamp top further comprises a horizontal segment and two descending vertical segments, and wherein the clamp base further comprises a horizontal segment and two ascending steps forming a ledge capable of contacting the descending vertical segments of the clamp top and constraining the force applied by the clamp top on the frameless photovoltaic modules, and wherein the elastomer comprises two horizontal segments and one vertical segment, and secures the end of said frameless photovoltaic module between said segments, and further wherein said upper horizontal segment of the elastomer is bonded to the clamp top horizontal segment, and said vertical horizontal segment of the elastomer is bonded to the clamp top descending vertical segments, and further wherein the clamp top, clamp base, and at least one elastomer are fixed in position by a bolt passing through the clamp top, adjacent to said vertical segments of the at least one elastomer, and through the clamp base, where it is adjustably secured with a nut.