A BUILDING FRAME ASSEMBLY AND A METHOD OF MANUFACTURING SUCH AN ASSEMBLY

Abstract: A building frame assembly and a method of manufacturing such an assembly, such as a door or window frame, has two elongate members 1, 1′ jointed together at their ends by a butt weld in a plane 7. Each member 1, 1′ has a thermoplastics outer sleeve 3 with a timber reinforcement 2. The sleeve 3 projects beyond the timber 2 to form a socket 4. Located in the socket 4 is a thermoplastics inner sleeve 5 which is preferably a complementary fit within the socket. The sleeve 5 can be retained by a settable material 6 in the bottom of the socket which material may provide a sealant for the timber reinforcement 2. The inner and outer sleeves 5 and 3 are cut to correspond with the angle of the joint in the plane 7 and the butt weld is effected between the end faces of the thermoplastics sleeves 3, 5, 3′ and 5′.

Description: TECHNICAL FIELD & BACKGROUND ART This invention relates to a building frame assembly and to a method of manufacturing such an assembly and is primarily concerned with assemblies which are manufactured from elongate members jointed together to form a corner and in which each elongate member comprises a sleeve of thermoplastics material housing a relatively rigid reinforcement. The invention was primarily developed for the assembly of window or door frames although it may be applied with advantage in the construction of other types of building frame assemblies where it is desirable that the rigid reinforcement of the jointed assembly has a protective and/or aesthetically pleasing surface provided by a thermoplastics skin. It is well known to manufacture door or window frame assemblies from lengths of timber enclosed within an extruded thermoplastics sleeve and to join the ends of such reinforced members to construct the door or window frame. However, experience has shown that difficulty can be experienced in effecting a strong joint between the members in a simple and economic manner. A conventional technique for jointing the two elongate members is by use of an injection moulded hollow corner piece which is spigoted into complementary sockets formed in the ends of the elongate members by extending the plastics sleeves of those members beyond the timber reinforcement. The spigots of the corner piece are secured in their respective sockets in the elongate members by use of a solvent adhesive and thereafter the corner piece is injected with a plastics foaming material (with the intention of filling the corner piece and providing a protective barrier to the timber). In general this technique has proved to be labour intensive, lengthly and inconvenient in the handling and application of the solvent adhesive and foam filling material. Furthermore, there may be some doubt whether the foam filling material is applied efficiently to fill the hollow corner and thereby leave voids where the corner may be without reinforcement and permit the ingress of moisture to the timber. A further prior proposal is disclosed in our British Patent No. 2,072,298 in which each elongate member is again provided with a socket at its end which is to be jointed and which socket is formed by the thermoplastics sleeve extending beyond the timber. Into this socket is located an injection moulded thermoplastics connecting member providing a relatively large surface area over which the member is to be butt jointed in appropriate angular disposition to a similar member by plastics welding. Although this latter proposal provides a simple and easily manufactured joint which can be fully sealed by welding there is the disadvantage that the thermoplastics material of the extruded sleeve and that of the injection moulded connector are usually incompatible (in the sense that they may not easily be welded together). Generally therefore some compromise has to be made to the desirable welding characteristics for the respective materials to permit them to be welded together. It is an object of the present invention to provide a building frame assembly and a method of manufacturing such an assembly by which the disadvantages of the aforementioned prior proposals may be alleviated. STATEMENT OF INVENTION & ADVANTAGES According to the present invention there is provided a building frame assembly having two elongate members which are jointed together at their ends by a butt weld and in a plane whereby the said members are maintained in a predetermined angular relationship, and in which each member comprises a thermoplastics outer sleeve and a reinforcement in said outer sleeve, the outer sleeve extending beyond the reinforcement at said end to provide a socket, a thermoplastics inner sleeve located in said socket, said inner and outer sleeves having substantially coplanar end faces at the said end of their respective elongate member, and wherein the butt weld is effected between the end faces of the thermoplastics sleeves of one member which oppose the end faces of the thermoplastics sleeves of the other member. Further according to the present invention there is provided a method of manufacturing a building frame assembly which comprises forming each of two elongate members by locating a reinforcement in a thermoplastics outer sleeve with an end of the outer sleeve extending beyond the reinforcement to form a socket; locating in the socket a thermoplastics inner sleeve; cutting the inner and outer sleeves to provide end faces thereon which are substantially coplanar and lie in a plane consistent with a predetermined angular relationship which is to be formed between the two members in the assembly, and welding the end faces of one member in abutting relationship with the end faces of the other member and with the two members in said angular relationship. By the present invention it is envisaged that the two members which are to be jointed together in the construction of the building assembly will each have its outer thermoplastics sleeve extending beyond its reinforcement to form a socket and into this socket is located, and preferably secured, an inner thermoplastics sleeve so that these two sleeves can then be cut or mitred to provide appropriately angled and coplanar end faces for its elongate member. These coplanar end faces of the two elongate members may easily be heated and welded together in opposing relationship to form a butt joint between the two members. This has the advantage that the provision of the inner sleeve can form an end face with a relatively large surface area for an efficient and strong welded joint. Furthermore, the inner sleeve can be, and is preferably, of the same thermoplastics material as that from which the outer sleeve is formed so that when two similar elongate members are jointed together the butt weld can be formed utilising the most efficient characteristics of a common plastics material. Preferably the inner sleeve member is formed by extrusion so that it can simply be cut to length for insertion into the socket of its elongate member. The reinforcement of the elongate members is preferably rigid and formed of timber although it will be appreciated that other reinforcement may be employed such as an aluminium or plastics foam core, or what may be regarded as compacted waste material. Usually the reinforcement will have a profile which presents longitudinally extending rebates or recesses on the elongate member and the outer plastics sleeve is extruded on to the reinforcement to follow the rebates or recesses in conventional manner. Preferably the inner sleeve is securely retained in the socket of the elongated member to ensure that the inner and outer sleeves are held in position relative to each other during the formation of the end faces and that those end faces are maintained coplanar during the butt welding operation. The inner sleeve may be retained in its socket by an interference or tight fit within the outer sleeve. Preferably however the inner sleeve is retained in its socket by use of a settable material which is deposited in the socket so that as the inner sleeve is inserted into the socket the sleeve dips into and sets in the settable material. The settable material is preferably in the form of a sealant which seals the end of the reinforcement adjacent to the socket; this is particularly advantageous where the reinforcement is timber so that the sealant may protect the timber against the ingress of water or moisture should the corner joint be damaged. Preferably the external profile of the inner sleeve corresponds to the internal profile of the outer sleeve so that the inner sleeve is received in the socket formed by the outer sleeve as a close, substantially, complementary fit. Preferably the inner sleeve is inserted into the socket of its elongate member to abut the reinforcement of that member and thereby be retained against displacement further into the outer sleeve. In the majority of assemblies, particularly for door and window frames, the joint formed between the two elongate members will be angled at 90° so that the coplanar end faces will be mitred in a 45° plane to their respective elongate members. However, it is to be realised that the present invention can be applied with advantage to the formation of joints which are angled other than at 90°, for example in the construction of pentagonal or hexagonal window frames. DRAWINGS One embodiment of a building frame assembly manufactured in accordance with the method of the present invention will now be described, by way of example only, with reference to the accompanying illustrative drawings in which:- Figure 1 is a perspective view of the end of an elongate member with its socket about to receive an inner sleeve, and Figure 2 is a longitudinal section of a corner joint of the frame assembly formed from two elongate members similar to that shown in Figure 1. DETAILED DESCRIPTION OF DRAWINGS The elongate member 1 (which is in the course of construction as shown in Figure 1) has a wood core reinforcement 2 which is profiled with longitudinally extending rebates and recesses to conform substantially to the profile required for the building frame assembly; such profiling may be achieved in conventional manner and in the present example the building frame assembly is conveniently regarded as a window frame. The length of wood 2 is received within a thermoplastics sleeve 3 which is extruded on to the wood in conventional manner to generally follow the profile of the core and present an accurately defined outer profile to the elongate member 1. The thermoplastics material of the sleeve 3 is preferably unplasticised polyvinyl chloride. The wood core 2 is positioned longitudinally within the sleeve 3 (conveniently by longitudinal displacement of the wood relative to the sleeve following appropriate cutting to length of the respective components) so that the sleeve 3 extends beyond the wood 2 to form a socket 4 in the end of the member 1. To be located in the socket 4 is an inner thermoplastics sleeve 5 having an external profile which substantially corresponds to the internal profile of the socket 4. The inner sleeve 5 which is preferably extruded and cut to length, is of a material which is compatible for welding with the material of the outer sleeve 3. Preferably the sleeves 3 and 5 are of the same thermoplastics. Usually the sleeve 5 will have a wall thickness substantially greater than the wall thickness of the sleeve 3. Prior to insertion of the sleeve 5 into the socket 4, a layer of settable material 6 is located in the bottom of the socket 4 to cover the end of the wood 2. The settable layer 6 is preferably a sealant and/or adhesive which may be applied in liquid form but is quick setting in the bottom of the socket. Examples of appropriate materials for the layer 6 are polyurethane elastomers, hot melt adhesives or RTV (room temperature vulcanisable) silicone rubbers. Prior to the layer 6 setting, the sleeve 5 is pushed as a close sliding fit into the socket 4 until it abuts the wood core 2 and its inner end dips into the layer 6 as shown in Figure 2. In this latter condition the outer end of the sleeve may project from the socket 4. As the layer 6 sets it provides a barrier to alleviate the ingress of water or moisture from the socket 4 into the end of the wood 2 and also serves to hold the sleeve 5 within the socket 4 during mitre cutting of the elongate member 1 as will be described. The member 1 is to form part of a 90° joint of a window frame and for this the outer and inner sleeves are cut or mitred simultaneously in a plane 7 which extends at 45° to the longitudinal extent of the member 1. During mitre cutting the inner sleeve 5 should be firmly retained relative to the outer sleeve 3 and this retention may be achieved by having the sleeve 5 as an interference fit within the sleeve 4 and/or by the adhesive or bonding effect of the layer 6. Following the mitre cutting the elongate member 1 is jointed to a second elongate member 1′ which is similarly formed to the member 1 (in Figure 2 the parts of the member 1′ similar to those of the member 1 are indicated by the same dashed references). The two members 1 and 1′ are to be welded together at opposing end faces in the plane 7 of the right angle joint shown in Figure 2. To achieve this welding, the 45° end faces of the inner and outer sleeves are subjected to a heated platen (not shown) so that the thermoplastics material is partially melted, the inclined end faces of the respective elongate members are then accurately positioned in opposition and pressed together to effect the right angle welded joint. During this welding operation the material of each of the inner and outer sleeves of the respective members 1 and 1′ will become welded, in the plane 7 of Figure 2, to the material of each of the other three sleeves in the corner joint so that a relatively firm and strong joint can be provided.

Claims: 1. A building frame assembly having two elongate members (1, 1′) which are jointed together at their ends by a butt weld and in a plane (7) whereby the said members are maintained in a predetermined angular relationship, each said member comprising a thermoplastics outer sleeve (3) and a reinforcement (2) in said outer sleeve, the outer sleeve (3) extending beyond the reinforcement (2) at said end to provide a socket (4), CHARACTERISED IN THAT a thermoplastics inner sleeve (5) is located in said socket (4), said inner and outer sleeves (3, 5) having substantially coplanar end faces at the said end of their respective elongate member (1, 1′), and wherein the butt weld is effected between the end faces of the thermoplastics sleeves (3, 5) of one member (1) which oppose the end faces of the thermoplastics sleeves (3′, 5′) of the other member (1′). 2. An assembly as claimed in claim 1 CHARACTERISED IN THAT the inner sleeves (5, 5′) and the outer sleeves (3, 3′) are of the same thermoplastics material. 3. An assembly as claimed in either claim 1 or claim 2 CHARACTERISED IN THAT at least one of the inner and outer sleeves (5, 3) is formed as an extrusion. 4. An assembly as claimed in any one of the preceding claims CHARACTERISED IN THAT the external profile of each inner sleeve (5) corresponds to the internal profile of the outer sleeve (3) within which it is received and said inner sleeves (5, 5′) are received in the respective outer sleeves (3, 3′) as substantially complementary fits. 5. An assembly as claimed in any one of the preceding claims CHARACTERISED IN THAT the inner sleeves (5, 5′) have a wall thickness greater that that of the outer sleeves (3, 3′). 6. An assembly as claimed in any one of the preceding claims CHARACTERISED IN THAT the reinforcement (2) is rigid. 7. An assembly as claimed in any one of the preceding claims CHARACTERISED IN THAT the reinforcement (2) comprises at least one of timber, aluminium, plastics foam and compacted waste material. 8. An assembly as claimed in any one of the preceding claims CHARACTERISED IN THAT a or each inner sleeve (5) is retained in its respective socket (4). 9. An assembly as claimed in claim 8 CHARACTERISED IN THAT the retention of each or an inner sleeve (5) is by a tight or interference fit of that sleeve in its associated socket (4). 10. An assembly as claimed in either claim 8 or claim 9 CHARACTERISED IN THAT the retention of each or an inner sleeve (5) is by use of a settable material (6) in the socket (4). 11. An assembly as claimed in any one of the preceding claims CHARACTERISED IN THAT a sealant (6) is provided in the bottom of each or a socket (4) to seal the end of the reinforcement (2) in that socket. 12. An assembly as claimed in claim 11 when appendant to claim 10 CHARACTERISED IN THAT the sealant is said settable material (6). 13. An assembly as claimed in either claim 10 or claim 12 CHARACTERISED IN THAT the settable material (6) comprises at least one of polyurethane elastomer, hot melt adhesive and RTV silicone rubber. 14. An assembly as claimed in any one of the preceeding claims CHARACTERISED IN THAT each or an inner sleeve (5) abuts the reinforcement (2) at the bottom of the socket (4) within which that inner sleeve is received. 15. An assembly as claimed in any one of the preceding claims CHARACTERISED IN THAT each of the inner and outer sleeves (3, 5) is welded substantially in said plane (7) to the respective other three of the inner and outer sleeves (3, 5, 3′, 5′). 16. An assembly as claimed in any one of the preceding claims and in the form of a door or window frame. 17. A method of manufacturing a building frame assembly which comprises forming each of two elongate members (1, 1′) by locating a reinforcement (22′) in a thermoplastics outer sleeve (3, 3′) with an end of the outer sleeve (3) extending beyond the reinforcement (2) to form a socket (4); CHARACTERISED BY locating in the socket (4) a thermoplastics inner sleeve (5); cutting the inner and outer sleeves (3, 5) to provide end faces thereon which are substantially coplanar and lie in a plane (7) consistent with a predetermined angular relationship which is to be formed between the two members (1, 1′) in the assembly, and welding the end faces of one member (1) in abutting relationship with the end faces of the other member (1′) and with the two members in said angular relationship. 18. A method as claimed in claim 17 CHARACTERISED BY extruding the outer sleeve (3) on to its respective reinforcement (2). 19. A method as claimed in either claim 17 or claim 18 CHARACTERISED BY cutting the outer sleeve (3) to length and displacing the reinforcement (2) longitudinally within that sleeve to provide the required socket (4). 20. A method as claimed in any one of claims 17 to 19 CHARACTERISED BY extruding the inner sleeve (5) for insertion into its respective socket (4). 21. A method as claimed in any one of claims 17 to 20 CHARACTERISED BY forming the inner sleeve (5) with an external profile which corresponds substantially to the internal profile of the outer sleeve (3) within which it is to be received and locating the inner sleeve (5) in the respective outer sleeve (3) as a substantially complementary fit. 22. A method as claimed in any one of claims 17 to 21 CHARACTERISED BY cutting the inner and outer sleeves (3, 5) to provide the substantially coplanar end faces of an elongate member while said inner sleeve (5) is located in its associated socket (4) so that the inner and outer sleeves (3, 5) are cut substantially simultaneously. 23. A method as claimed in any one of claims 17 to 22 CHARACTERISED BY locating the inner sleeve (5) in its socket (4) to abut the reinforcement (2). 24. A method as claimed in any one of claims 17 to 23 CHARACTERISED BY retaining the inner sleeve (5) in its respective socket (4) as a tight or interference fit. 25. A method as claimed in any one of claims 17 to 24 CHARACTERISED BY retaining the inner sleeve (5) in its respective socket (4) by a settable material (6) in the socket (4). 26. A method as claimed in any one of claims 17 to 25 CHARACTERISED BY providing a sealant (6) in the bottom of the socket (4) to seal the end of the reinforcement (2) in that socket. 27. A method as claimed in claim 26 when appendant to claim 25 CHARACTERISED BY providing a layer (6) of a settable sealant in the bottom of the socket (4) and inserting the inner sleeve (5) into that socket (4) prior to the sealant setting so that the inner sleeve (5) dips into the sealant (6) whereby, when the sealant sets, it seals the end of the reinforcement (2) and retains the inner sleeve (5) in the socket (4). 28. A method as claimed in any one of claims 17 to 27 CHARACTERISED BY welding the end faces so that each of the inner and outer sleeves (3, 5) is welded substantially in said plane (7) to the respective other three of the inner and outer sleeves (3, 5, 3′, 5′). 29. A method as claimed in any one of claims 17 to 28 CHARACTERISED BY welding the two members (1, 1′) together by heating the end faces of each member with a heated platen and then bringing those heated end faces of the two members together in abutting relationship. 30. A building frame assembly when manufactured by the method as claimed in any one of claims 17 to 30.

Inventors: BALKWILL, GEOFFREY LEONARD
Applicants: BLACKNELL BUILDING PRODUCTS LIMITED
Application year: 1986
Main classification: E06B3
IPC codes: E06B3, B29C65