AU2004205125B2 - Method of attaching non-metal frame to metal frame, and metal and non-metal frame adapted for such method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method of attaching a non-metal frame to a metal frame, and a metal and non-metal frame adapted for such method. In particular the invention relates to a method of attaching a non-metal frame such as decorative wooden 5 frame to a metal frame such as an aluminium door or window frame. However, it is to be understood that the invention is not to be limited as such. Moreover, because the invention may have many other applications, the prior art and possible applications of the invention discussed below are given by way of example only. BACKGROUND ART 10 Non-metal frames such as wooden or plastics decorative frames are often attached to metal window and door frames in order to enhance the appearance of the window or door frame and to match with the interior decor of a room. A basic method of attaching non-metal frames involves simply bonding the non-metal frame to the metal frame with adhesive. In this case to ensure a neat appearance at the join, a thin film of adhesive is 15 applied to the surfaces, so that when clamped and bonded, the joint is practically invisible. However, due to the difference in coefficient of expansion of non-metal and metal frames, and due to shrinkage and warping in the case of a wood frame, the bond usually fails with time. Therefore, it is also necessary to provide mechanical fastenings, such as screws through the metal frame into the non-metal frame. Hence time is required to fit the 20 mechanical fasteners. Moreover, when bonding the non-metal frame this must be aligned carefully and then screwed in position which also takes time. Furthermore, the screw heads can detract from the final appearance. DISCLOSURE OF THE INVENTION It is an object of the present invention to address the above problems with 25 attachment of non-metal frames to metal frames, or to at least provide the public with a useful choice. According to a first aspect of the present invention there is provided a method of attaching a non-metal frame to a metal frame using adhesive, comprising the steps of: forming a spacing rib of a predetermined height around an outer periphery of an 30 attachment area of the metal frame and/or the non-metal frame; applying an adhesive of appropriate flexibility to one or both surfaces of the non metal frame and metal frame within an area bounded by the spacing rib, and in a suitable

I

amount so as to give a predetermined width and area when the two frames are held together; and bringing the two surfaces together and holding in position until the adhesive sets. 5 By providing a spacing rib of a predetermined height around the outer periphery of the attachment area, the adhesive can be provided in a predetermined thickness between the two surfaces, while still having a neat practically invisible join around the edge of the frame. Moreover by applying a suitable amount of adhesive to give a predetermined width of adhesive, the adhesive in its finally set state can hold 10 the two frames together, and can flex with differential expansion or contraction of the non-metal frame, without failing. The predetermined width and thickness of the adhesive depends on the type of adhesive used. For example in the case of 3M Scotch-Seal 5300TM polyurethane general purpose seam sealer, a thickness of 0.7 to 1.0 mm and a maximum width of 15 2mm is suitable for allowing transverse flexing of the adhesive without failure over time. Preferably the adhesive is applied over a part of the area in the form of a continuous wavy line of a predetermined width and bead height. A suitable width may be for example 2mm with a bead height of between 1.1 20 and 1.5 times the height of the spacing rib for a rib of 0.7 to 1.0 mm. Having a bead height slightly higher than the height of the spacing rib ensures that the adhesive adequately contacts both surfaces to give a good bond. Preferably the height does not exceed 1.5 times the height of the spacing rib (gap width). If the height is too great, the width of the adhesive strip after squashing 25 will be too wide, and will not allow sufficient transverse flexure of the set adhesive, resulting in eventual failure over time. According to another aspect of the invention, the method further comprises a step of providing location means on the metal frame for locating with location means provided on the non-metal frame. 2 By providing location means, the non-metal frame can be easily and accurately located relative to the metal frame at the time of assembly, thus ensuring consistent quality of assembly. The location means may comprise for example a protruding member in the 5 form of a rod or an elongate strip. In the case of a rod, the non-metal frame would be provided with corresponding holes, while in the case of a strip the non-metal frame would be provided with corresponding recesses. Moreover the location means may also include holding means for holding the two frames together once assembled, at least for a sufficient time to allow the 10 adhesive to set. In this case the step of holding the two frames in position until the adhesive sets is achieved by the holding means. According to another aspect of the invention, the method further comprises a step before the step of applying an adhesive, of forming one or more deep elongate grooves in the non-metal frame within the attachment area. 15 By forming one or more elongate deep grooves in the non-metal frame within the attachment area, the material of the non-metal frame in the vicinity of the attachment area can expand and contract by a greater amount without causing overall expansion and contraction of the non-metal frame. Hence the attachment area has a greater resistance to failure of the adhesive. 20 According to another aspect of the present invention there is provided a non metal frame adapted for attachment to a metal frame by means of the above described method, comprising; a spacing rib of a predetermined height formed around an outer periphery of an area over which said metal frame is to be attached. 25 According to another aspect of the present invention there is provided a metal frame adapted for attachment to a non-metal frame by means of the above described method, comprising; a spacing rib of a predetermined height formed around an outer periphery of an area over which said non-metal frame is to be attached. 3 The metal frame may further comprise protrusions protruding from the area of attachment, and the non-metal frame may be formed with recesses for accurately accommodating the protrusions. Furthermore, the protrusions may be formed with a deforming and/or 5 deformable tip for deforming the non-metal frame, and/or for being deformed by the non-metal frame when inserted in the recess of the non-metal frame. With such a construction, the non-metal frame can be maintained in a tightly held together condition until the adhesive sets, thereby obviating the need for additional clamps to hold the two frames together. 10 The present invention may also broadly be said to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more of the parts, elements or features, and where specific integers are mentioned herein which have known equivalents in the art to which this invention relates, such known 15 equivalents are deemed to be incorporated herein as if individually set forth. BRIEF DESCRIPTION OF THE DRAWINGS Further aspects of the present invention will become apparent from the ensuing description which is given by way of example only and with reference to the accompanying drawing in which; 20 FIG. 1 is a sectional view of a window frame and non-metal frame illustrating a method of attachment according to an embodiment of the present invention. FIG. 2 is a sectional view of a window frame and non-metal frame illustrating a method of attachment according to another embodiment of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION 25 Embodiments of the present invention will now be described with reference to FIG. I and FIG. 2. As shown in FIG. 1 a metal frame 1 in the form of an aluminium extrusion window frame which is attached to a non-metal frame 2 in the form of a decorative wood frame, by the method of the present invention, comprises a spacing rib 4 30 formed around an outer periphery of a metal attachment surface of the metal frame 1 4 generally indicated by arrow 6. Moreover the metal frame I is provided with location means in the form of two elongate protrusions 8 for locating with recesses 10 formed in the non-metal frame 2 for locating the non-metal frame 2 relative to the metal frame 1. The protrusions 8 in this case are elongate upstanding members formed on 5 the metal attachment surface 6 of the metal frame 1 along the full length. Such protrusions 8 are easily formed when extruding the metal frame 1. However the protrusions need not necessarily be continuous strips and may for example be in the form of intermittent protrusions at intervals along the metal attachment surface 6, or in the form of rod like protrusions, depending on the manufacturing methods used. 10 In this embodiment the tips of the protrusion 8 are in the form of barbs 14 which can deform the non-metal frame 2 when inserted in the recesses 10 of the non metal frame 2. Moreover, as shown in FIG. 1, additional recesses in the form or one or more deep elongate grooves 15 are formed in the non-metal frame 2 within the attachment 15 area. Preferably these grooves extend the full length of the non-metal frame 2 and are formed at the same time as forming the spacing ribs 4 and the recesses 10. However, they may be formed after forming the spacing ribs 4 and the recesses 10, by for example cutting into the attachment area surface with a router or saw. By forming these deep elongate grooves 15 in the non-metal frame within the attachment area, the 20 material of the non-metal frame in the vicinity of the attachment area can expand and contract by a greater amount without causing overall expansion and contraction of the non-metal frame 2. Hence the attachment area has a greater resistance to failure of the adhesive. Fitting the non-metal frame 2 to the metal frame 1, involves cleaning both 25 surfaces (for example including cleaning off any wax or dirt with a solvent, and/or scuffing the metal surface), and then applying an adhesive 16 of appropriate flexibility to one or both surfaces of the metal attachment surface 6 and a non-metal attachment surface 18 of the non-metal frame 2, within an area bounded by the spacing rib 4, and in a suitable amount so as to give a predetermined width and area 30 when the two frames 1 and 2 are held together. For example in this embodiment, the adhesive 16 is applied as a wavy line along the length of the metal frame 1 from one edge to the other within the area bounded by the spacing ribs 4, with a bead height 5 slightly higher than a height X of the spacing ribs 4 (in the cross-section of FIG. 1 and FIG. 2, the adhesive 16 is shown as a single location, which could be anywhere on the metal attachment surface 6 within in the area bounded by the spacing ribs 4, or 104, depending on the cross-section taken). Then the two surfaces 6 and 18 are 5 brought together and held in position until the adhesive sets. Due to the spacing ribs 4 along the outer periphery of the attachment surface 6, the adhesive is squashed to the thickness of the spacing ribs 4, between the two surfaces 6 and 18, and in its finally set state can hold the two frames 1 and 2 together. Moreover a height H of the adhesive strip (equal to the height X of the spacing ribs 4) 10 and width W of the adhesive strip is such as to allow the adhesive 16 to flex with expansion or contraction of the non-metal frame 2 relative to the metal frame 1, without failing. In this embodiment, due to the barbs 14 on the end of the elongate protrusions 8 biting into the non-metal frame 2, this is held tightly in place once clamped against 15 the metal frame 1. Hence there is no need to keep holding the two frames 1 and 2 together by external means until the adhesive sets. It is important when applying the adhesive 16 to avoid filling adhesive into the recesses 10 in the non-metal frame 2. If too much adhesive 16 enters the recesses 10, the adhesive 16 can prevent the two surfaces 6 and 18 from being brought 20 together and held in position, since the adhesive in the recesses will tend to act as a cushion, and push the surfaces away when the clamping force is released. The recesses 10 are thus made deep enough so that this does not happen. FIG. 2 shows a second embodiment of the present invention. In FIG. 2, parts having a similar function to those of FIG. 1 are denoted by the same reference 25 symbols, and description is omitted or abbreviated. In the second embodiment of FIG. 2, a metal frame 101 has a similar function to the metal frame 1 of the first embodiment. For example this is a metal window frame. This metal frame 101 differs from the metal frame I of FIG. 1 in that there is no spacing rib 4 along the periphery of the metal attachment surface 6. Instead a 30 spacing rib 104 is formed along the periphery of the attachment area 18 of a non metal frame 102. 6 Moreover, the deforming tips on the end of protrusions 108 are in the form of one sided double barbs 114. With this design for the protrusions 108, accurate alignment of the non-metal frame 102 relative to the metal frame 101 can be achieved since one side of the protrusion 108 does not deform, and slides accurately along the 5 side of a recess 110. Moreover, having the two barbs 114 on one side achieves a similar holding function to that of the first embodiment with a single barb on each side. With this embodiment also, the required height of the adhesive to avoid failure with time, can be ensured by the height of the spacing rib 104. 10 We believe the advantages of our invention to be as follows, however it should be appreciated that all such advantages may not be realised on all embodiments of the invention and the following list is given by way of example only as being indicative of potential advantages of the present invention. Furthermore it is not intended that the advantages of the present invention be restricted to those of the 15 list which follows: I. By providing a spacing rib around the periphery of a join between the metal and non-metal frame, the required height of the adhesive to avoid failure with time, can be ensured, thus enabling two frames with different coefficients of thermal expansion to be reliably attached using adhesive, without the need for mechanical 20 fasteners such as screws. 2. Having the spacing rib around the edge of the frames ensures a neat and consistent joint line between the two members. 3. By providing the protrusion on the metal frame, the non-metal frame can be accurately located on the metal frame, thus simplifying assembly. 25 4. By providing the barbs on the tips of the protrusions, the non-metal frame can be held in position on the metal frame until the adhesive sets. Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope of the invention as defined in the appended claims. 30 7

Claims (16)

1. A method of attaching a non-metal frame to a metal frame using adhesive, comprising the steps of: forming a spacing rib of a predetermined height around an outer periphery of 5 an attachment area of said metal frame and/or said non-metal frame; applying an adhesive of appropriate flexibility to one or both surfaces of said non-metal frame and said metal frame within an area bounded by said spacing rib, and in a suitable amount so as to give a predetermined area and width suitable for allowing transverse flexing of the adhesive without failure over time when said two 10 frames are held together; and bringing said two surfaces together and holding in position until said adhesive sets.

2. A method of attaching a non-metal frame to a metal frame according to claim 1, wherein said adhesive is applied over a part of said area in the form of a continuous 15 wavy line of a predetermined width and bead height.

3. A method of attaching a non-metal frame to a metal frame according to either one of claim 1 and claim 2, further comprising a step of providing location means on said metal frame for locating with location means provided on said non-metal frame.

4. A method of attaching a non-metal frame to a metal frame according to claim 20 3, wherein said location means comprises a protruding member in the form of a rod and said non-metal frame is provided with corresponding holes.

5. A method of attaching a non-metal frame to a metal frame according to claim 3, wherein said location means comprises a protruding member in the form of an elongate strip and said non-metal frame is provided with corresponding recesses. 25

6. A method of attaching a non-metal frame to a metal frame according to any one of claim 3 through claim 5, wherein said location means also includes holding means for holding said two frames together once assembled, at least for a sufficient time to allow said adhesive to set, and said step of holding said two surfaces in position until said adhesive sets is achieved by said holding means. 8

7. A method of attaching a non-metal frame to a metal frame according to any one of claim 1 through claim 6, further comprising a step before said step of applying an adhesive, of forming one or more deep elongate grooves in said non-metal frame within said attachment area.. 5

8. A non-metal frame adapted for attachment to a metal frame by means of the method of attaching a non-metal frame to a metal frame according to any one of claim 1 through claim 7, comprising; a spacing rib of a predetermined height formed around an outer periphery of an area over which said metal frame is to be attached. 10

9. A non-metal frame according to claim 8, formed with recesses for accurately accommodating protrusions of said metal frame.

10. A non-metal frame according to either one of claim 8 and claim 9, further comprising one or more deep elongate grooves formed within said area.

11. A metal frame adapted for attachment to a non-metal frame by means of the 15 method of attaching a non-metal frame to a metal frame according to any one of claim 1 through claim 7, comprising; a spacing rib of a predetermined height formed around an outer periphery of an area over which said non-metal frame is to be attached.

12. A metal frame according to claim 11, further comprising protrusions 20 protruding from said area.

13. A metal frame according to claim 12, wherein said protrusions are formed with a deforming and/or deformable tip for deforming said non-metal frame, and/or for being deformed by said non-metal frame when inserted in a corresponding recess in said non-metal frame. 25

14. A method of attaching a non-metal frame to a metal frame substantially as described herein with reference to the appended drawings.

15. A metal frame substantially as described herein with reference to the appended drawings. 9

16. A non-metal frame substantially as described herein with reference to the appended drawings. M. J. SERVICE & ASSOCIATES Attorneys for: 5 Aluminium Systems NZ Limited 10