Abstract:
A backlight assembly for a convertible roof of a vehicle has a fabric roof cover having a backlight opening formed therein and a plurality of apertures formed therein about a periphery of the backlight opening. A glazing is disposed in the backlight opening. The glazing has a flange extending about a periphery thereof which overlaps a portion of the fabric roof cover. The flange has a plurality of fastener-receiving structures, each of which are received within a corresponding one of the plurality of apertures in the roof cover. A first frame member extends about a periphery of the glazing and overlaps the flange and sealingly engages the roof cover. A second frame member extends about periphery of the glazing and overlaps the flange. The second frame member is disposed opposite the first frame member with the flange and the roof cover disposed therebetween. The second frame member has a plurality of fasteners, each interlocking with a corresponding one of the fastener-receiving structures to fasten the second frame member to the flange to thereby secure the glazing to the roof cover.

Description:
This application claims the benefit of Provisional Application No. 60/054,393 filed Jul. 31, 1997. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to an insert molded frame and glazing assembly, and more particularly, to an insert molded frame and glazing assembly for use as a backlight, or rear window, of a convertible roof top for an automobile and a method for making the same. 
     BACKGROUND OF THE INVENTION 
     In conventional convertible roof tops for automobiles, the roof is made primarily of a fabric material with a clear vinyl panel employed as a backlight. The vinyl panel is attached around its periphery to an opening in the fabric roof top so as to be substantially permanently attached to the fabric. The permanent attachment of the vinyl panel to the fabric roof makes it virtually impossible to replace only the vinyl panel should it become weathered or torn. To replace a weathered or torn vinyl backlight, it is often necessary to replace the entire soft portion of the convertible roof top. 
     Rigid glass panels have also been employed in convertible roof tops because they are more resistant to weathering and are not prone to tearing. Because such panels are rigid, however, they do not neatly fold into a small package for stowing and are further susceptible to cracking or shattering. 
     Accordingly, the need exists for a soft, flexible backlight for a convertible roof top which may be separately removed from the fabric portion of the roof top yet is securely fixed at its perimeter to the backlight opening in a weather-tight fashion. 
     SUMMARY OF THE INVENTION 
     The disadvantages of the prior art may be overcome by providing a backlight assembly for a convertible roof of a vehicle. The assembly comprises a fabric roof cover having a backlight opening formed therein and a plurality of apertures formed therein about a periphery of the backlight opening. A glazing is disposed in the backlight opening. The glazing has a flange extending about a periphery thereof which overlaps a portion of the fabric roof cover. The flange has a plurality of fastener-receiving structures, each of which are received within a corresponding one of the plurality of apertures in the roof cover. A first frame member extends about a periphery of the glazing and overlaps the flange and sealingly engages the roof cover. A second frame member extends about periphery of the glazing and overlaps the flange. The second frame member is disposed opposite the first frame member with the flange and the roof cover disposed therebetween. The second frame member has a plurality of fasteners, each interlocking with a corresponding one of the fastener-receiving structures to fasten the second frame member to the flange to thereby secure the glazing to the roof cover. 
     It is desirable to provide a method for securing a backlight glazing into a backlight opening formed in a fabric cover of a convertible roof of a vehicle. The method comprises the steps of: 
     providing a fabric cover with a backlight opening and a plurality of apertures extending about a periphery of the backlight opening; 
     providing a glazing having a plurality of fastener-receiving structures formed about a flange extending from a periphery of the glazing, the plurality of fastener-receiving structures being constructed and arranged to permit each of the fastener-receiving structures to be received within a corresponding one of the apertures in the roof cover when the glazing is inserted through the backlight opening; 
     forming a first frame member secured to the periphery of the glazing and overlapping the flange by placing the periphery and flange of the glazing into a cavity of a mold assembly and injecting flowable molding material into the cavity and permitting the molding material to be molded directly to the periphery and flange of the glazing to form a first frame member; 
     positioning the glazing and the first frame member with respect to the backlight opening so that each of the fastener-receiving structures is received within a corresponding one of the apertures, the flange overlapping a portion of the fabric cover; 
     providing a second frame member and positioning the second frame member opposite the first frame member with the overlapping portions of the flange and the fabric cover disposed between the first and second frame members and fastening the second frame member to the fastener-receiving structures, sandwiching the fabric between the flange and the second frame member thereby securing the glazing to the fabric cover. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In drawing which illustrate embodiments of the present invention, 
     FIG. 1 is a partial plan view of a convertible roof top backlight; 
     FIG. 2 is a cross-sectional view of a frame and glazing assembly according to a first embodiment of the present invention taken along the line A—A in FIG. 1; 
     FIG. 3 is a cross-sectional view of a frame and glazing assembly according to a second embodiment of the present invention taken along the line A—A in FIG. 1; 
     FIG. 4 is a partial cross-sectional view of an injection mold assembly for forming one part of the frame and glazing assembly of the present invention; and 
     FIG. 5 is a partial cross-sectional view of an injection mold assembly for forming one part of the frame and glazing assembly of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A convertible roof backlight, generally indicated at reference number  10 , is shown in FIG.  1 . The roof  10  comprises a fabric portion  18  having a backlight opening formed therein within which is secured a frame and glazing assembly  12 . The glazing  16  preferably comprises a panel of flexible polycarbonate material. Surrounding the glazing panel  16  and securing the glazing to the fabric  18  is a peripheral frame  14  extending continuously around the glazing panel  16 . 
     A first embodiment of the frame and glazing assembly  12  is shown in FIG.  2 . The frame  14  comprises a first frame member  20  and a second frame member  22 . First and second frame members  20  and  22  preferably extend continuously around the periphery of the glazing  16  and are preferably formed by injection molding a thermoplastic material, preferably a polycarbonate blend such as ASA or PMMA. In the preferred embodiment, first frame member  20  is an exterior frame and second frame member  22  is an interior frame. 
     First frame member  20  preferably includes a section  26  which is substantially coplanar with the glazing  16 , a rounded edge  31  on the glazing side of the frame member, and a sloping portion  30  on the fabric side of the frame member. Sloping portion  30  terminates in a flexible lip  28 . The underside of the frame member has a planar surface  25  which is substantially coplanar with the glazing  16  and an inner edge  24  which is substantially perpendicular to the planar surface  25  and extends at a right angle therefrom. Planar surface  25  and inner edge  24  define an interior shelf for receiving a peripheral edge of the glazing panel  16 . 
     A sealant groove  32  is also preferably formed on the underside of the first frame member  20  below sloping section  30  and also extends around the entire periphery of the frame  14 . 
     The glazing panel  16  comprises a central portion  51  typically having a thickness between 3.5 and 6 millimeters and a peripheral flange  50  having a reduced thickness as compared to the central portion  51 . The thickness of flange  50  of the glazing  16  is the same as the height of the inner edge  24  of the first frame member  20 . 
     The first frame member  20  is preferably formed by an injection molding process wherein the glazing  16  is inserted into the injection mold and the first frame member is molded into the glazing  16  so as to create a bond line  80  between the first frame member  20  and the glazing  16  at the interfaces of the planar surface  25  and the inner edge  24  with the peripheral edge of the glazing  16 . 
     Second frame member  22  includes a first section  42  that is substantially coplanar with the glazing  16 , an angled section  44 , and a second section  46 . The first section  42 , angled section  44 , and second section  46  define an inner open area  40 , the height of the inner open area  40  being slightly less than the difference in the thickness between the central portion  51  and the flange  50  of the glazing  16 . Second frame member  22  preferably has glazing-side and fabric-side rounded edges  72 ,  74 . 
     Defined within the inner open space  40  are first and second knife edges  34 ,  36  extending into the open space  40  and having a height approximately the same as that of the open space  40 . Knife edges  34  and  36  are preferably continuous, extending about the entire periphery of the frame  14 , but may also be discontinuous, i.e. being in the form of discrete spikes or cleats. 
     An aperture  38  extending through the first section  42  of the second frame member  22  is preferably provided between the first knife edge  34  and the second knife edge  36 . Aperture  38  has a countersink  48 . 
     The glazing  16  is formed with a plurality of fastener receiving structures  86  formed about its periphery and extending from the flange  50 . As can be appreciated from FIG. 2, the height of the fastener receiving structure  86  is preferably the same as the difference between the thickness of the central portion  51  and the thickness of the flange  50  of the glazing  16 . The fastener receiving structures  86  are spaced about the periphery of the glazing  16  with a spacing determined by the particular application and/or the expected localized loads in that area of the perimeter. 
     The fastener receiving structures  86  each include a raised boss portion  52 , which is preferably cylindrical in shape. An insert aperture  54  is provided in the center of the boss portion  52  and extends into the boss portion  52  and is coaxial therewith. An inner chamber  56  is defined within the boss portion  52  and communicates with the insert aperture  54 . The diameter of the inner chamber  56  is greater than that of the insert aperture  54 , thus defining an annular, inwardly facing shoulder  57  at the interface of the insert aperture  54  and the inner chamber  56 . 
     The frame and glazing assembly  14  is assembled as follows. The sealant groove  32  is filled with a suitable sealant material  70 , which may be any flowable elastomeric material, preferably urethane. The sealant  70  provides bonding of the first frame member  20  with the fabric  18  and further provides sealing therebetween. The fabric  18  has apertures  82  corresponding in size and spacing to the fastener receiving structures  86  of the glazing  16 . The fabric  18  is positioned on the inner surface of the first frame member  20  and glazing  16  assembly with the fastener receiving structures  86  protruding through the corresponding apertures  82 . The fabric  18  is supported on an inwardly facing surface  58  of the flange  50  of the glazing  16  and also on a support surface  84  of the first frame member  20 . 
     The second frame member is positioned against the fabric  18  and glazing  16  on the opposite side as the first frame member  20 . Aperture  38  of the second frame member  22  is aligned with the insert aperture  54  of the fastener retaining structure  86 . Surface  76  of the second frame member  22  bears against a portion of the glazing  16 , thus sandwiching the glazing  16  between surface  76  and surface  25  of the first frame member  20 . Fabric  18  is also sandwiched between surface  78  of the second frame member  22  and surface  84 , sealant  70 , and flexible lip  28 , which deflects upwardly when the second frame member  22  is pressed against the first frame member  20 . The elastically deflected lip  28  biased toward an undeflected position provides an improved seal between first frame member  20  and fabric  18 . 
     Second frame member  22  is secured to the first frame member  20  by frame fasteners  60  having a head portion  62  and a shank portion  64 . When installed, head portion  62  is seated within counter sink  48 . Fastener  60  has an enlarged tip portion  66  having a frusto-conical shape which permits the enlarged tip to be inserted through the insert aperture  54  and into the inner chamber  56  of the boss  52  of the fastener receiving structure  86 . It can be appreciated that the frusto-conical surface of the enlarged tip  66  causes the insert aperture  54  to expand, thus permitting the enlarged head to pass therethrough. An annular shoulder  68  is defined between the interface of the shank  64  and the enlarged tip  66 . Shoulder  68  engages the shoulder  57  of the fastener receiving structure  86 , thus resisting extraction of the fastener  60  from the fastener receiving structure  86 . Frame fastener  60  is preferably formed of a suitable thermoplastic material including polycarbonate blends such as ASA and PMMA. 
     As can be appreciated from FIG. 2, with the fastener  60  inserted into the fastener receiving structure  86 , the glazing  16  and fabric  18  are sandwiched between the first frame member  20  and the second frame member  22 . The knife edges  34  and  36  press into the fabric  18  and glazing  16  to tightly hold the fabric  18  in the frame and glazing assembly  12  and limit the bearing forces imposed on the aperture  82  of the fabric  18 . 
     A second embodiment of the frame and glazing assembly is represented generally by a reference number  12 ′ in FIG.  3 . In FIG. 3, components and features in the framing and glazing assembly that are the same as those shown in FIG. 2 are given identical reference numbers as shown in FIG.  2 . 
     In the second embodiment of the frame and glazing assembly  12 ′, second frame member  100  includes a first planar surface  114  that is substantially parallel to the glazing  16  and fabric  18  with rounded ends  102  and  104 . At the glazing end of the second frame member  100 , a notch portion  106  is provided. Notch  106  defines a second planar surface  118  that is substantially parallel to first planar surface  114  and an inner edge  120  that is substantially perpendicular to planar surface  118 . The height of inner edge  120  is slightly less than the difference between the thickness of the glazing  16  at section  51  and the thickness of the glazing  16  at flange  50 . 
     In the second embodiment of the frame and glazing assembly  12 ′, the glazing  16  and first frame member  20  are physically the same as the like structures in the first embodiment shown in FIG.  2 . 
     Second framing member  100  is preferably formed of a suitable thermoplastic material including polycarbonate blends such as ASA and PMMA. Second frame member  100  includes a plurality of insert apertures  108 , associated counter sinks  110 , and openings  112 , preferably cylindrical in shape and coaxial with aperture  108 , spaced about the peripheral extent of second frame member  100 . 
     Second frame member  100  is preferably formed by injecting molding, with the fabric  18  inserted into the mold so that the perimeter of the backlight opening of the fabric extends into the injection mold. The second frame member  100  is then injection molded onto the backlight opening perimeter so as to form a bond line  116  between the second framing member  100  and the fabric  18 . 
     The frame and glazing assembly  12 ′ is assembled by placing the second frame member  100  on the opposite side of the glazing  16  and fabric  18  from the first framing member  20  with the boss portions  52  of the fastener receiving structures  86  being received into the openings  112  formed in the second frame member  100 . The glazing  16  is sandwiched between surface  118  of the second framing member  100  and surface  25  of the first framing member  20 , and the fabric  18  is sandwiched between surface  114  of the second frame member  100  and bearing surface  58  of the glazing  16 , bearing surface  84  of the first frame member  20 , sealant  70 , and lip  28  of the first framing member  20 . 
     Second framing member  100  is held in place by inserting a fastener  60  through aperture  108  and into the fastener receiving structure  86  of the glazing  16  in a snap fit. Again, the fastener head  62  of the fastener  60  is seated within the counter sink  110  of the second frame member  100 , and an enlarged tip portion  66  retains the fastener  60  within the fastener receiving structure  86 . 
     As illustrated in FIG. 4, a process for forming second frame member  100  of the embodiment illustrated in FIG. 3, preferably by injection molding, is illustrated. The process includes a mold, preferably made of metal, having a first part  122 , and a second part  124 . First and second mold parts  122  and  124  cooperate to define a continuous peripheral molding cavity. 
     First mold part  122  includes a molding surface defined by an inner surface  126  having a plurality of inwardly extending hole forming portions  139 , an edge surface  134  defining generally a right angle with inner surface  126 , and a surface  130  extending from edge surface  134  in a generally parallel orientation with respect to inner surface  126 . Intersecting surfaces  134  and  130  form an outwardly facing shoulder potion  137  that dimensionally is the difference between the thickness of glazing panel central portion  51  and peripheral flange  50  of glazing  16 . 
     The hole forming portions  139 , extending inwardly from inner surface  126  of first mold part  122 , are preferably cylindrically shaped and each defines a larger cylindrical section  138  and a smaller cylindrical section  140 . The larger cylindrical section  138  is diametrically sized to form opening  112  of frame member  100  (see FIG. 3) preferably having a depth equal to that of edge surface  134 . The number and orientation of hole forming portions  139  correspond to the plurality of fastener receiving structures  86 , spaced about the periphery of the glazing  16 . 
     Smaller cylindrical section  140  extends axially from each of the larger cylindrical sections  138  having a smaller diameter that corresponds to aperture  108  of second frame member  100  (see FIG.  3 ). The smaller cylindrical section  140  extends inwardly and communicates with an inner surface  142  of the second mold part  124 . At the intersecting portion of inner surfaces  126  and  134 , first mold part  122  may include a groove  144  which extends laterally from inner surface  126 , thereby allowing the fabric  18  to slidingly enter thereinto. 
     Second mold part  124  includes a mold surface defined by an inner surface  158 , a first arcuate inner surface  160 , and a second inner arcuate surface  164 . Inner surface  158  is generally parallel with inner surface  126  of first mold part  122 . A plurality of inwardly extending frusto-conical portions  154  extend from inner surface  158 . Frusto-conical portions  154  are axially aligned with the hole forming portions  139  of the first mold part  122  and are sized to form the counter-sunk portions  110  of second frame member  100 . A plurality of injection gates  156  are provided about the periphery of the mold assembly. In the illustrated embodiment, injection gate  156  extends through second mold part  124 . It will be understood that injection gates could be provided in either or both the first mold part  122  and second mold part  124 . 
     The first mold part  122  cooperates with the second mold part  124  to define a mold cavity  168  which is substantially the same size and shape as frame member  100 . More specifically, when first mold part  122  is placed into proper orientation with second mold part  124 , inner surface  166  of second mold part  124  engages surface  130  of first mold part  122 , and inner surface  126  of first mold part  122  and surface  162  of second mold part  124  sandwich the fabric  18  therebetween on the fabric side. An inwardly facing circular surface  141  of the smaller cylindrical portion  140  engages with the inner surface  142  of the frusto-conical portion  154 . 
     Injection gate  156  in the second mold part  124  provides a means to inject molding material into the mold cavity  168  thereby forming frame member  100 . It can be appreciated that a number of injection gates would extend into mold cavity  168  around the periphery of the second mold part  124  and/or the first mold part  122  in order to ensure that mold cavity  168  is completely filled and properly evacuated during the forming process such that frame member  100  is solidly and completely formed. 
     Second frame member  100  is preferably formed by injection molding of any suitable thermoplastic material including polycarbonate blends such ASA or PMMA. 
     Fabric  18  is inserted into the mold with hole forming portions  139  of the first mold  122  extending through fabric apertures  82 . The fabric thusly lays flat against the inner surface  126 . Second mold part  124  is then placed onto the first mold part  122  and resin material  170  is injected through injection gates  156  into the mold cavity  168  thereby forming frame member  100 . Additionally, the molten thermoplastic material adheres to the fabric in the mold thus creating a bond line  116  between framing member  100  and fabric  18 . 
     As illustrated in FIG. 5, a process for forming the top frame member  20 , preferably by injection molding, is illustrated. The process is substantially the same as for molding frame member  100  and includes a mold, preferably made of metal, comprising a first mold part  172  and second mold part  174 . 
     First mold part  172  includes a molding surface defined by a surface  188  that extends into an inwardly sloped convex surface  190  which extends into an inwardly sloped concave surface  178  and finally into an inwardly sloped surface  180 . The sloping surface  180  continues until it terminates at a second surface  192 . The inner surface  188  extends arcuately inward forming a rounded inner surface  194  which intersects with a surface  196  on the glazing side. Preferably located in a central portion of the first mold part  172  is one or more injection gates  186  extending therethrough. 
     Second mold part  174  includes a molding surface defined by an inner surface  206  which intersects an inwardly formed surface  208  having a height that conforms to the size of sealed groove  70  on the fabric side. Extending from surface  208  is a first portion  200  generally parallel to surface  206  and a sloping surface  210  that terminates at the end of sloping surface  180  of first mold part  172  thereby defining the form of flexible lip  28  of frame member  20 . Extending on the fabric side is a second surface  212  that is substantially coplanar with second surface  192  of first mold part  172 . 
     On the glazing side, inner surface  206  ends at edge surface  214  that extends at a right angle therefrom and intersects surface  216 . The height of edge surface  214  corresponds to the difference in thickness between the glazing panel central portion  51  and flange  50  of glazing  16 . 
     A plurality of wells  220  are formed into the inner surface  206  of second mold part  174 . The wells  220  are sized to accommodate the fastener receiving structures  86  of glazing  16  and are formed about the periphery and are aligned to admit a corresponding plurality of fastener receiving structures  86  spaced about the periphery of the glazing  16 . 
     The first mold part  172  cooperates with the second mold part  174  to define mold cavity  224 . More specifically, when first mold part  172  is oriented with respect to second mold part  174 , planar inner surfaces  192  of first mold part  172  and  212  of second mold part  174  engage each other on the fabric side and inner surfaces  196  of first mold part  172  and  216  of second mold part  174  sandwich glazing panel central portion  51  therebetween. 
     The injection gates  186  in first mold part  172 , provide a means to inject molding material into mold cavity  224 , thereby forming frame member  20 . It can be appreciated that a number of injection gates may extend into mold cavity  224  around the periphery of first mold part  172  and/or second mold part  174  in order to ensure that frame member  20  is solidly and completely formed. 
     Frame member  20  is preferably formed by injection molding in the same manner as frame member  100  using any suitable thermoplastic material. The glazing  16 , is inserted into the second mold part  174  such that the fastener receiving structures  86  are placed into the wells  220  and ensuring the glazing inner surface lays flat against the inner surface  206  of second mold part  174 . First mold part  172  is then placed onto second mold part  174  and the resin material  170  is injected through injection gates  186  into the cavity therebetween, thus forming frame member  20 . The molten material adheres to the glazing  16  creating a bond line  80  between the first frame member  20  and the glazing  16  at the planar surface  25  and inner edge  24 . 
     It thus will be seen that the objects of this invention have been fully and effectively accomplished. It will be realized, however, that the foregoing preferred embodiments of the present invention have been shown and described for the purposes of illustrating the structural and functional principles of the present invention and is subject to change without departure from such principles.