GB1599747A

GB1599747A - Composite article comprising a glass panel and a surrounding frame therefor

Info

Publication number: GB1599747A
Application number: GB25521/78A
Authority: GB
Original assignee: Motors Liquidation Co
Current assignee: Motors Liquidation Co
Priority date: 1977-06-10
Filing date: 1978-05-31
Publication date: 1981-10-07
Also published as: AU3690578A; JPS5416738A; CA1098708A; AU520053B2; IT1105203B; IT7849802A0; FR2393663A1; DE2825411A1

Description

(54) COMPOSITE ARTICLE COMPRISING A GLASS PANEL AND A SURROUNDING FRAME THEREFOR (71) We. GENERAL MOTORS CORPORATION, a Company incorporated under the laws of the State of Delaware. in the United States of America, of Grand Boulevard, in the City of Detroit. State of Michigan. in the United States of America (Assignees of LAWRENCE EDWIN SCHROEDER and CARLTON MICHAEL BURGESS) do hereby declare the invention for which we pray that a patent may be granted to us. and the method by which it is to be performed to be particularly described in and by the following statement: This invention relates to the mould-forming of articles and more particularly to the manufacture of composite articles including a glass and frame unit in which a frame surrounds the edge of the glass.

While the invention has an abundance of applications, a use that has been of immediate importance has been in the development of solar collector or heater units, and the description of the invention will proceed with particular reference thereto. The advantages which will be pointed out in the context of that limited use will be seen as only a partial list and of broader significance in such fields as windows and other building products, and in furniture.

Prior solar collector assemblies have utilized various framing devices for mounting glass and a solar heat collector plate. These framing devices have been associated with single or multiple layers of glass in spaced relation to the collector plate to admit solar energy thereto while preventing heat loss from the collector plate to the atmosphere. Some materials utilized for solar collector framing have included wood and metal, particularly aluminium.

Various fastening means for the glass to the frame connection have been tried, including the use of adhesives or cement and the use of various gasket members. Although these materials and methods have worked successfully. it is believed that the subject disclosure of a unitary glass and frame member made by moulding represents an advantageous and highly desirable advance in the art. The advantages are to be discussed hereinafter. First, however. some of the disadvantages of the aforementioned earlier materials and methods will be discussed.

The use of metal or wood frames normally involves joining together a plurality of parts which must be assembled in fairlv accurate relation to one another to mount a glass panel or panels therein. The labour cost in forming this assembly will be quite significant and when larger volume production is contemplated. the labour cost in assembling wood and metal frames becomes quite excessive. Some materials, such as wood, do not provide sufficient durability and there are associated maintenance expenses. The use of a metal, such as aluminium, for a frame out-of-doors or in building exteriors may permit significant heat losses due to the high thermal conductivity of the material. In an attempt to lessen the effect of heat loss through the metal, insulation may be required about the glass edge and thus the unit dimensions will be increased in relation to the solar heat collecting area.

A composite article according to the invention comprises a glass panel and a surrounding frame therefor. said frame being formed of material which exhibits shrinkage following moulding or exhibits a linear expansion significantly different from that of glass, in which said composite article comprises: a glass panel, a packing strip mounted over the edge portion of said glass panel, and a perimeter-supporting frame of the above-recited material mould-formed about said packing strip and glass edge portion in said moulding process, said packing strip having a collapsible zone formed of an inner region of greater softness than the remainder of said strip, situated outwardly of the terminal edge of said glass panel, and structured to be susceptible to forces in the plane of said glass panel so as to allow relative movement between the latter and said frame in said plane to occur without substantial force during post-mould shrinkage of said frame or differential linear expansion thereof relative to said glass panel when said composite article is in use.

A unitary glass and frame member made in accordance with the invention is readily moulded in a single operation to produce an economical and useful structure which has many desirable features. A perimeter frame of polyurethane material serves to protect the glass panel or panels from shock-related breakage and provides with the glass an electrically nonconductive assembly. The frame provides an enclosed space adjacent and below the glass panel to receive a solar collector surface and associated insulation. The wall encircling the glass panel may be tapered outward so that a plurality of the glass and frame members may be stacked in cuplike fashion one upon another prior to insertion of the associated solar heat collector parts. Polyurethane material has very good durability and the maintenance required is low. Unlike metals, such as aluminium, polyurethane does not have corrosion problems and unlike wood, the polyurethane material does not rot and require painting. Polyurethanes generally and in the so-called structural foam variations particularly, have very beneficial thermal insulative properties for this and like uses. In fact, it is readily seen that the various advantages just listed commend the article of the present invention to many uses other than solar collectors.

In a particularized practice of the invention, a unitary glass and polyurethane frame member is inexpensively manufactured in large volumes by the application of the known reaction injection moulding process, also known as liquid injection moulding. Specifically, polyurethane components are mixed and injected into a closed mould. The pressures in the mould are relatively low when compared to the more commonly utilized injection moulding for thermosetting or thermoplastic materials in which mould pressures may range from 10,O(X) to 20,00() pounds per square inch. In reaction injection moulding, the pressures in the mould are typically below about 75 pounds per square inch. These low mould pressures permit moulding of relatively large assemblies, such as in the present application, without the need for an enormous moulding machine or super rigid dies. By way of example only, the glass panels of a preferred embodiment measure approximately 34 inches by 92 inches and the outer dimensions of the frame measure about 38.4 inches by 96.4 inches. The frame width is about 3 inches and this translates into a parting area between mould pieces of almost 800 square inches. With mould pressures of about 75 pounds per square inch, the clamping force needed would equal about 60,00() pounds. Thus, a relatively light 30-ton press would be sufficient.

In general, a glass panel and frame member according to the invention is manufactured as follows. A generally U-shaped cross section seal strip formed from a medium to medium-firm durometer elastomer and having therein a collapsible zone formed of an inner region of greater softness than the remainder of said strip is first mounted on the edge of the glass panel. The leg portions of the strip extend along the surface of the glass and inward toward its centre. The glass panel with the strip thereon is placed in a mould cavity of moulding apparatus and, specifically, with one of the strip legs resting upon an upstanding ridge-like projection of one mould piece, which projection extends continuously inboard the edge of the glass panel. Then the corresponding upper half or piece of the moulding apparatus is brought into operative relationship with the first mould piece. It, too, has a continuous ridge-like projection to engage the opposite leg of the seal. This forms a closed mould space about the edge of the glass and seal into which the polyurethane material is injected to result in a composite article having a frame mould-formed around the edge of the glass.

These and other advantages and features of the present invention will be more readily apparent from an understanding of the following detailed description, reference being had to the accompanying drawings in which preferred embodiments of the unitary glass and frame are shown.

In the drawings: Figure 1 is a plan view of a solar collector unit including a unitary glass and frame member, all according to the present invention; Figure 2 is a view looking in the direction of arrows 2--2 in Figure 1: Figure 3 is an enlarged sectional view taken along section lines 3--3 in Figure 1; Figure 4 is a fragmentary sectioned view taken along section lines 4--4 in Figure 3 and looking in the direction of the arrows; Figure 5 is a partial edge view of the glass and frame member as situated between mould pieces immediately subsequent to injection of synthetic plastics material into the mould cavity; Figure 6 is a fragmentary sectioned view of a second embodiment showing the frame edge and a dual glass panel and strip; Figure 7 is a perspective view of the particular elastomeric strip utilized on the glass panel of Figure 3; Figure 8 is a fragmentary view similar to Figure 5 showing alternative moulding apparatus and an alternative U-shaped strip: Figure 9 is an enlarged view of a portion of Figure 8; Figure 10 is a perspective view similar to Figure 7 showing an alternative U-shaped strip; Figure 11 is a perspective view illustrating moulding apparatus suitable to the present invention: and Figure 12 is another view similar to Figure 6 showing an alternative strip for a dual glass panelled article.

In Figures 1 and 2. there is illustrated a solar collector or heater unit including a unitary glass and frame member 10. all in accordance with the present invention. The member 10 includes a glass panel 12 which preferably is of a convenient modular size. The glass panel 12 is encircled by a perimeter frame 14 mould-formed of polyurethane or like polymeric material.

Details of the shape of frame 14 are apparent in Figures 1 - 3 which disclose the wall-like frame with indented wall portions 16 and rib-like portions 18. This configuration may obviously take many forms without departing from the scope of the present invention. The illustrated configuration of frame 14 is adapted to impart rigidity to the frame. As best shown in Figure 3. frame 14 is moulded about the outer edge portion 12' of the glass panel 12. A wall portion 20 extends substantially normal to the plane of the glass panel 12 from the portion 22 about the glass edge 12'. Integrally formed therewith and continuous with the wall portion 20 is a slightly outboard second wall portion 24. The juncture between wall portions 20 and 24 forms a shoulder 26. The wall portions 20 and 24 encircle a space adjacent and below the glass surface of panel 12 in which a solar heat exchanger or collector panel assembly 28 is supported. In Figures 1, 3 and 4, particularly, the collector panel assembly 28 is shown and includes a substantially flat collector plate 30 of aluminium or other material having a high thermal conductivity. The plate 30 has a series of parallel crimped portions 32 adapted to partially encircle lengths 34 of a copper, or like material, conduit or pipe. Such pipe is bent into a serpentine pattern as best shown in Figure 1. One end 36 is directed downward toward the bottom of the frame 14 to form a fluid inlet while the other end 38 forms the fluid outlet. Liquid is pumped through the continuous copper conduit to transfer heat from the plate 30. As shown in Figure 3, the collector panel assembly 28 including plate 30 and copper conduit 34, is held along the frame edge between a narrow upper blanket of insulation 40 and a lower blanket of insulation 42. The collector panel assembly 28 and insulation 42 is supported at its bottom by a thin panel 44 of board-like insulative material. The edge of panel 44 engages the shoulder 26 and is attached by means of staples 46. The solar collector panel assembly 28 may take many forms and in the present description of the application of the invention to solar collector units it is not intended to limit the use of the unitary glass and frame member to any particular collector configuration.

Engaging the outer edge portion 12' of glass panel 12 is a rectangular-plan strip 48 of generally U-shaped cross section as best shown in Figures 3. 7. The strip 48 is preferably a single integral unit. made of elastomeric material. and includes relatively thin laterally extending leg portions 50 which, when the strip is stretched and mounted over glass edge portion 12', will snugly engage the surfaces of said edge portion all around panel 12. As best shown in Figure 7. the leg portions 50 have a thin cross section and a rounded inboard end 52. On the inside surface of the leg portions are a series of ridges 54. These are felt to aid in accommodating any dimensional variations and their effects on the moulding process, as will appear. At the base of the leg portions and outboard from the ridges 54 is located, in one form, an enlarged bottom portion 56 into which the outer edge portion of the glass panel 12 may extend. Still further outboard from the bottom portion 56 is located, by way of a preferred form of a collapse zone. a cavity 58 with, in this particular illustration, a hexagonal configuration which cavity extends continuously through the strip 48 around the associated glass panel.

The outboard cavity 5X provides a space or zone to prevent from developing in the assembly undue stress caused by differing expansion characteristics of the glass panel 12 and the surrounding frame 14. Specifically. it has been found that in any attempt to mould-form a composite article having a polymeric or like material frame around a glass panel, the post-mould shrinkage which generally occurs with mould polymers, and even in nonpolymeric mouldable materials, will place severe stresses within the article resulting in fractures thereof, particularly the glass. while curing or during handling. The bodily contraction of the polyurethane element. frame 14, relative to the glass must be accommodated without producing substantial force or stress. In accordance with one feature of the invention, the strip 48 is provided with a collapsible compression zone outboard of the terminal edge of glass edge portion 12', as seen, for example, in Figure 3, extending generally continuously around glass panel 12, and particularized there in the form of cavity 58. The zone defined by this cavity enables post-mould relative movement of the contracting polymeric frame 14 with respect to the glass panel without any substantial resulting stress being induced therein. since the cavity 58 readily permits volume reduction directly within the body of strip 48 under relatively light forces. The strip member 48 is thus seen as being in the nature of a packing element which is firm for intimate moulding of frame 14 about the strip member over glass edge portion 12', and yet provides a relatively soft compliance function to achieve the advantages set forth above.

The strip 48 with its collapse zone also accommodates differential thermal expansion and contraction between the glass 12 and the frame 14 during use of the solar collector unit. An iron-free tempered glass of the type used in one preferred embodiment of the solar collector unit normally has a coefficient of linear expansion of 4.7 x 10-6 inches per inch per degree Fahrenheit. A polyurethane material used in this same embodiment for frame 14 and having an average specific gravity of 0.55 has a linear expansion coefficient of 40 x 10-6 inches per inch per degree Fahrenheit. Thus, the linear expansion (and wherever herein that term is used, contraction is also implied) of the glass per degree temperature change is substantially less than the expansion and contraction of the surrounding polyurethane frame. With increasing temperatures, the polyurethane frame will enlarge more than the glass panel and with decreasing temperatures. the polyurethane frame 14 will shrink in dimension more than the glass. Consequently. assuming for the moment the absence of strip 48 and the glass edge 12' thus being embedded directly within a full thickness of the material of frame 14, even slight temperature changes in a large composite article of this type, (or, of course, substantial temperature changes in even small articles) would create extreme stresses within the two elements of the composite article which, it has been found, the glass particularly cannot tolerate without breaking. The collapsing zone of the strip 48, again. provides that necessary compliance to relative movement that eliminates the creation of destructive stresses.

Referring now to the process in detail. Figure 5 illustrates first and second mould pieces 60, 62 which when brought together on either side of the glass panel 12 and strip 48 form a cavity into which mouldable material is then injected to form the peripheral polyurethane frame 14. In the particular cross section shown in Figure 5, the midportion of a ridge 18 is illustrated. Both mould members 60. 62 have projecting narrow ridge-like projections 64, 66 which are continuous along the seal and prevent the flow of the moulded material out of the cavity and onto the surface of the mid-portion of glass 12. Such a flow of the moulded material onto the glass can be particularly destructive when, for example, the moulded material is a polyurethane or like polymer which can adhere strongly to the surface of the glass. Any leakage of the polyurethane out of the mould cavity and onto the glass would thus require scrapping of the article or a polyurethane removal technique elaborate enough to leave the glass surface unimpaired. Accordingly, preferred feature of this invention is in the use of a strip member which serves as a mould-piece seal providing a dam which prevents such material flow onto the panel element of the composite article during moulding. It is highly advantageous to combine such a mould-piece sealing function directly within the strip 48 so that strip 48 alone serves the two functions of compliance of relative movement and mould-piece sealing.

Thus, returning to the cross sectional view of Figure 5, the process entails, in a preferred version, the mounting over glass edge portion 12' of a combined-function strip 48 of such configuration in section as to have laterally extending legs, such as 50, which project a distance inboard of the terminal edge of the glass as shown so as to be engageable by mould piece ridge projections. such as the narrow projections 64 and 66 at the edges of the mould cavities of the mould pieces 60 and 62. During the process, and with the mould pieces 60 and 62 at first separated, the mould piece 60 (or 62 if it be the lower one) lies open to receive directly in its mould cavity the panel 12 with the strip 48 thereon. The glass panel 12 would be laterally adjusted in all directions within such mould cavity to have the lower leg 5() of strip 48 resting upon ridge projection 64 all around such ridge as in the relation seen in Figure 5. The mould piece 62 would then be brought generally into the moulding relationship shown in Figure 5 and in which the upper ridge projection 66 engages the upper leg 50 of strip 48. A final closing movement is then applied to the mould pieces to bring them closer together in such a manner as to deform the thickness of legs 50 at the narrow regions throughout the length thereof engaged by the ridge projections 64 and 66. This amounts to a highly localized squeezing of the legs causing material flow thereof from under and to around the ridge projections so that the result is a substantial pressure-proof fluid dam preventing flow of the moulded material out of the cavity onto the midportion of glass panel 12. all as viewed in Figure 5. A particularized specification for such deformation will be set forth in connection with another Figure hereinafter.

It should be noted that after the mould pieces 60, 62 are removed and the frame is exposed. the projecting inboard end portions 52 of the legs 50 are trimmed flush with the edge of frame portion 22. This trimming serves two purposes. First, the trimming away of the leg portions a greater glass area for entry of solar energy. Secondly, the trimming prevents water and foreign particles from getting between the glass and the inside surface of the leg portions.

As mentioned hereinabove. advantage is had in the combining within strip 48 of both the relative movement compliance and mould-piece sealing functions. However, a highly specialized strip 48 necessarily results since the two functions conflict with one another when strip material is considered. For example, a foam or sponge elastomer material or even a non-elastomer strip with suitable collapsible structure, could be satisfactory for the movement compliance function, but would be unacceptable as a mold-piece seal. A high durometer elastomer material could be satisfactory for sealing purposes but, without special provisions. would generally not in itself allow relative movement under shrinkage or temperature growth without developing high forces in the glass. Accordingly, an elastomer strip 48 serving both functions is fabricated through extrusion to have a generally U-shaped configuration such as seen generally in Figures 5 and 7, is provided with a compression zone such as cavity 58, and has a material specification in which a key element is material hardness generally in the medium to medium-firm durometer range of from 40 to 60.

Satisfactorv material hardness and other factors are present, for example, in a commercially available rubber strip material having a specification according to the following code of the American Society of Testing and Materials: ASTM D 2000 ' CA 515 B 44 F 1721 Grade 2 rubber Durometer (hardness) 50 + 5 Tensile strength 1500 psi Compression Set 35% max. in 70 hrs. &commat; 100" C.

Cold Temperature Flex -40 F.

Ozone and Heat Aged Figure 6 illustrates a fragmentary view of a second embodiment showing a unitary glass and frame structure with dual glass panels. The glass panels 68, 70 have an integral generally single-E-shaped strip 72 slipped over glass edge portions 68', 70'. The strip 72 has a leg portion 74 which extends along the outer surface of the outer glass panel and a leg portion 76 extending along the bottom surface of the inner glass panel. A midportion or web 78 projects slightly between glass panels to space them and supports the panels 68, 70.

Otherwise. the strip 72 is similar to seal 48 and it includes ridged inner surfaces 80, enlarged end portions 82, and cavities 84. The moulding operation is similar to that described in association with Figure 5. The projecting portions of the mould pieces engage inboard portions of legs 74. 76 to prevent any flow of moulded material over the glass surface.

The midportion 78 of this E-type of the generally U-shaped strip is a feature of the second embodiment of this invention. It has been found possible to mould this dual glass composite article, despite the great inherent susceptibility to breakage of the glass panels for lack of proper support in the mould pieces. if the midportion 78 projects inboard a distance generally about as far as does the inner terminal edge of the frame 14; i.e., generally equal to the trimmed length of legs 74. 76. The length of midportion 78 illustrated in Figure 6 is somewhat short of that, and is about the limit of shortness which such a midportion should have to properly support the glass edge portion 68' and 70' within the mould pieces. It preferably should not extend beyond said inner terminal edge so as to occlude the glass panel area or provide unsightly interspace between glass panels. In any event, a durometer firmness figure for the strip 72. such as suggested hereinabove, provides a midportion 78 sufficiently rigid to support the glass panels inside the mould-piece cavities and offer that resistance necessary to the pinching pressure of the mould-piece ridge projections for mould-piece sealing.

The particular embodiment shown in Figure 6 would be applicable for use in northern climates, where the double glass panel provides extra insulation to prevent undue heat loss due to severe wind effects. It should be noted that in Figure 6. the inboard ends of the legs 74, 76 have not yet been trimmed flush with the frame. Trimming of this portion will provide more glass area for passage of solar energy. A third or more solar glass panels might be provided, and a multiple E-shaped strip would serve to suitably stack such multiple panels.

As indicated hereinabove. polyurethane material has been found quite suitable to the solar collector application of the invention described herein. Specifically, reaction injection moulding, also known as liquid injection moulding, is advantageous to this application in that low mould pressures are utilized and solar collector units are preferably of such a large size that pressures can be a limiting factor when tooling expense is of concern. Further, that process enables the use of polyurethane or like polymer materials introduced with a foaming agent for the purpose of achieving a so-called structural foam having a relatively low density core but a high density outer skin region. Such a polyurethane frame provides a rigid support for the solar collector unit shown in Figures 3 and 4, yet the side walls 20, 22 of the polyurethane frame may have excellent insulating properties, with a conductivity factor of only about 0.55 when the overall specific gravity of the polyurethane frame is also about 0.55. To arrive at the aforesaid overall specific density of about 0.55, the moulding charge specifications and mould cooling requirements are set to produce an outer skin having a density of about 65 pounds per cubic foot. while the midportion of the thick wall sections has a density of only about 2 pounds per cubic foot. Thus, it can be seen that the range of densities varies greatly and this is an advantageous factor in producing a strong and lightweight frame with good insulating properties.

Figure 8 illustrates details of a mould-piece design alternative to that illustrated in Figure 5. Rather than the narrow generally rectangular ridges with flat surfaces of that Figure, the mould pieces 6() and 62 may incorporate corresponding projections 64' and 66' of a sloping ledge configuration merging with the edge of the mould cavity of each mould piece. The two sloping projections are preferably identical in detail and each includes, as best illustrated in the enlarged Figure 9. a sloping wall 86a directed outwardly to merge with a very narrow (0.060 inches or so) land 86b at the edge of the mould cavity. The inboard extremity of wall 86a merges with the generally horizontal flat base surface of the mould piece. It has been found that the slope of the projection wall 86a is best made shallow, the angle 0 between it and the flat base wall, as shown in Figure 9, being kept in a range of around 10 . particularly. when the medium to medium-firm durometer elastomer is used for strip legs 50.

As set forth above in the detailed process description, the final closing movement of mould pieces 60 and 62 into final moulding relationship is intended to cause the ridge projections of the mould pieces to deform the legs 50. When using the sloped projections of Figure 8. a depth of penetration of each projection into a leg 50-- dimension a of ridge 66' in Figure 9 -- of about 0.02 inches has been found to produce the desired result. Thus, with an illustrative total normal thickness of glass panel 12 and strip legs 50 either side thereof of about 0.397 inches, final closing movement of the mould pieces after initial engagement of each surface 86b with its respective leg 50, to bring the final gap between the two surfaces 86b to about 0.357 inches, will produce sufficient degree of material flow in legs 50 around the sloping projections to create the fluid dam. An alternative cavity 58' for strip 48 of a rectangular configuration in Figure 8 illustrates the choices available.

Figure 10 shows yet another configuration for strip 48 in which the enlarged end portion 56 is eliminated in favor of fullv flat inner surfaces inside legs 50 merging with a bottom portion provided with an arcuate section sealing rib 88 running the length of strip 48. The flat inside leg surfaces may aid in eliminating cocking of the strip 48 on the glass edge during mould process or otherwise. The rib 88. particularly under post-mould shrinkage of the frame 14. will tightly engage the terminal glass edge and aid in providing a moisture seal preventing migration of water or foreign matter from the exterior to underneath the glass panel 12. A completely circular form of cavity 58" is illustrated in Figure 10.

Figure 11 illustrates a mold apparatus which has been found suitable to achieve the process steps outlined hereinabove, yet with relatively low cost and complexity. Thi pieces for strip squeezing may be derived from final movement of the hydraulic jacks 102, or by additionally actuating a series of rotary or like clamps 104 affixed to the upper mould piece 60 and engageable with a flange of mould piece 62 or table 90. Mouldable material is introduced into the common mould cavity of the mould pieces 60 and 62 through an injecting and mixing head 106 incorporated at one end of the mould piece 60. Adjacent the other end, another hydraulic actuator 108 is affixed between the mould piece and a post 96 to selectively tilt the joined mould pieces about the axis of pivots 98. Thus, during injection of mouldable material into the joined mould pieces, air may escape the tilted mould cavity through a single vent 110 adjacent actuator 108. Following moulding and untilting, the rotary clamps are released, table 90 and mould piece 62 are lowered on bed 94, and then the table and mould piece are moved by the screw drive back to original position wherein the completed composite article may be removed from the mould piece 62.

Figure 12 illustrates still another embodiment of a dual glass panel composite article for solar collector units. Again, rectangular cavities 84' may be employed in lieu of hexagonal or circular shaped cavities and it will be apparent that many other shapes of cavity may be found suitable. Also, partial curing or similar process expedients in the forming of elastomer strips 48 and 72 may lead to the utilization of soft or foam cores within the strips to substitute for fabricated cavities therewithin, yet with care not to sacrifice the hardness or stiffness needed in the areas of legs 50 or 74, 76 for mould-piece sealing. The midportion 78' illustrated in Figure 12 for the strip 72 has the advantage of a rounded end facilitating initial mounting of the strip around the glass edges.

WHAT WE CLAIM IS: 1. A composite article comprising a glass panel and a surrounding frame therefor, said frame being formed of material which exhibits shrinkage following moulding or exhibits a linear expansion significantly different from that of glass, in which said composite article comprises: a glass panel, a packing strip mounted over the edge portion of said glass panel, and a perimeter- supporting frame of the above-recited material mould-formed about said packing strip and glass edge portion in said moulding process, said packing strip having a collapsible zone formed of an inner region of greater softness than the remainder of said strip, situated outwardly of the terminal edge of said glass panel, and structured to be susceptible to forces in the plane of said glass panel so as to allow relative movement between the latter and said frame in said plane to occur without substantial force during post-mould shrinkage of said frame or differential linear expansion thereof relative to said glass panel when said composite article is in use.

2. A composite article according to claim 1, in which said packing strip is of elastomeric material. and said collapsible zone is readily compressible in volume under the relative movement between the glass panel and said frame in the plane of said glass panel without the exertion of substantial force during said post-mould shrinkage of said frame of said differential linear expansion thereof relative to said glass panel.

3. A composite article according to claim 1, in which the packing strip is an elastomeric packing and mould-piece seal strip having laterally extending legs, said strip being mounted with its legs embracing the edge portion of said glass panel, which legs are in sealing engagement with the mould pieces during said moulding process, and said perimeter frame is formed of polymeric material mould-formed about said strip and glass edge portion, the legs of said strip completely intervening said frame and the glass panel throughout the perimeter of said frame.

4. A composite article according to claim 1, in which the packing strip is a generally U-shaped elastomeric packing and mould-piece seal strip mounted with the legs thereof embracing the edge portion of said glass panel, said legs being in sealing engagement with the mould pieces during said moulding process, and being formed from a medium to medium-firm durometer elastomer and completely intervening said frame and the glass panel throughout the perimeter of said frame, and the collapsible zone of said strip comprising a shaped cavity in the base of the U-shaped strip extending the length of the strip.

5. A moulded solar heat collector including a composite article according to any one of the preceding claims, in which said frame includes an enclosing wall portion extending generally normal to the plane of said glass panel, and there is a heat collecting panel mounted within said wall portion adjacent to and below said glass panel which heat collecting panel includes conduit means through which fluid may be made to flow, and thermal insulation means within said wall portion.

6. A composite article according to any one of claims 1 to 4, in which the article includes at least two glass panels. said packing strip is of elastomeric material mounted over juxtaposed edge portions of said glass panels, said strip has at least a single generally E-type cross section including a middle web interposed between each juxtaposed pair of edge portions of said glass panels and extending inboard a predetermined distance from the

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. pieces for strip squeezing may be derived from final movement of the hydraulic jacks 102, or by additionally actuating a series of rotary or like clamps 104 affixed to the upper mould piece 60 and engageable with a flange of mould piece 62 or table 90. Mouldable material is introduced into the common mould cavity of the mould pieces 60 and 62 through an injecting and mixing head 106 incorporated at one end of the mould piece 60. Adjacent the other end, another hydraulic actuator 108 is affixed between the mould piece and a post 96 to selectively tilt the joined mould pieces about the axis of pivots 98. Thus, during injection of mouldable material into the joined mould pieces, air may escape the tilted mould cavity through a single vent 110 adjacent actuator 108. Following moulding and untilting, the rotary clamps are released, table 90 and mould piece 62 are lowered on bed 94, and then the table and mould piece are moved by the screw drive back to original position wherein the completed composite article may be removed from the mould piece 62. Figure 12 illustrates still another embodiment of a dual glass panel composite article for solar collector units. Again, rectangular cavities 84' may be employed in lieu of hexagonal or circular shaped cavities and it will be apparent that many other shapes of cavity may be found suitable. Also, partial curing or similar process expedients in the forming of elastomer strips 48 and 72 may lead to the utilization of soft or foam cores within the strips to substitute for fabricated cavities therewithin, yet with care not to sacrifice the hardness or stiffness needed in the areas of legs 50 or 74, 76 for mould-piece sealing. The midportion 78' illustrated in Figure 12 for the strip 72 has the advantage of a rounded end facilitating initial mounting of the strip around the glass edges. WHAT WE CLAIM IS:

1. A composite article comprising a glass panel and a surrounding frame therefor, said frame being formed of material which exhibits shrinkage following moulding or exhibits a linear expansion significantly different from that of glass, in which said composite article comprises: a glass panel, a packing strip mounted over the edge portion of said glass panel, and a perimeter- supporting frame of the above-recited material mould-formed about said packing strip and glass edge portion in said moulding process, said packing strip having a collapsible zone formed of an inner region of greater softness than the remainder of said strip, situated outwardly of the terminal edge of said glass panel, and structured to be susceptible to forces in the plane of said glass panel so as to allow relative movement between the latter and said frame in said plane to occur without substantial force during post-mould shrinkage of said frame or differential linear expansion thereof relative to said glass panel when said composite article is in use.

terminal edge of said edge portions, and said perimeter supporting frame, mould-formed about said packing strip and said glass edge portions, extends inwardly from the terminal edge of said edge portions a distance not substantially further than the predetermined distance of said web so as to provide adequate support from said web for said glass panels during said moulding process.

7. A method of moulding a composite article according to claim 1, which method comprises the steps of: mounting on the edge portion of said glass panel a generally U-shaped cross section seal strip, said seal strip being formed from a medium to medium-firm durometer elastomer and having therein a collapsible zone formed of an inner region of greater softness than the remainder of said strip, so as to have the legs of said strip embrace and extend inwardly a predetermined distance from the terminal edge of said panel edge portion; placing the unit of the panel and seal strip on one mould piece to have the panel edge portion and strip lie in a mould cavity thereof and with one leg of said strip engaging a ridge projecting thereof; moving the mould pieces into a moulding relationship with one another in which a corresponding ridge projection of the other mould piece engages the other leg of said strip; applying final closing movement to said mould pieces so that said ridge projections thereof deform the engaged portions of said legs of said strip to produce a highly localized squeezing of the strip material to establish a dam against the flow of mouldable material from the mould cavity past said ridge projections of the mould pieces: filling the mould cavity of the closed mould pieces with mouldable material; and then separating said mould pieces for removal of the composite moulded article.

8. A composite moulded article substantially as hereinbefore particularly described and as shown in Figures 1 to 5 and Figure 7 of the accompanying drawings.

9. A composite moulded article substantially as hereinbefore particularly described and as shown in Figures 1 to 5, as modified by Figure 6 of the accompanying drawings.

10. A composite moulded article substantially as hereinbefore particularly described and as shown in Figures 1 to 5, as modified by Figures 8 and 9 of the accompanying drawings.

11. A composite moulded article substantially as hereinbefore particularly described and as shown in Figures 1 to 5, as modified by Figure 10 of the accompanying drawings.

12. A composite moulded article substantially as hereinbefore particularly described and as shown in Figures 1 to 5, as modified by Figure 12 of the accompanying drawings.

13. Apparatus for carrying out a process of manufacturing a composite moulded article substantially as hereinbefore particularly described and as shown in Figures 1 to 5, substantially as hereinbefore particularly described and as shown in Figure 11 of the accompanying drawings.