GB2157793A - Corner joints for architectural frames - Google Patents

Abstract

An architectural frame is constructed from sheet metal members (14,15,16) rolled into channel form and mitred at the corners. Inside and parallel to the lateral flanges (20,21) of these members are welded blanking plates (30,31;40), which project beyond the mitre line. When each 17 corner is made, portions of these plates overlap, with the plates (30,32) on one member press fitting in pockets (50 Fig. 6) in the other member formed between its banking plates (40) and lateral flanges (20,21). Detents (34,44) in the blanking plates inter-engage to enhance the rigidity of the corner. Additionally, hooked plates (41,42) welded to the web 22 of one channel engage over and behind the web of the other channel at each corner, first to serve as a fulcrum whilst the blanking plates are being interdigitated, and finally to receive fasteners. <IMAGE>

Description

SPECIFICATION Corner joints for architectural frames This invention relates to corner joints for architectural frames such as are used in doorways and window openings for example, though the invention can be applied in general to any type of architectural frame for an opening in a wall.

A common form of building construction for walls employs light metal studs or frame members with panels of plasterboarding or the equivalent applied on opposite sides and there is a need for a frame which can be positioned in an opening through such a wall and can be readily assembled and erected and will be secure and of good appearance when installed. It is desirable that the frame should provide firm "tight" corner joints and that it can be installed after a wall has been constructed and the opening formed, as opposed to methods of construction in which the frame is erected first and the wall built around the frame.

Broadly stated the invention consists in an architectural frame including two adjacent sheet metal frame members each of generally channel cross-section, the frame members being mitred at their ends and formed to engage and interlock, the side flanges of the two channels being mitred on the external surface, but provided with internal overlapping blanking plates.

Preferably one of the internal blanking plates is spaced from the adjacent side flange of the channel by a narrow gap approximately equal to the thickness of the blanking plate on the other channel. In a particular preferred construction the base web of one of the channels is cut off on the plane of the mitre, but is provided with an additional bracket having a flange arranged to hook over the web of the channel of the other frame member. The hook flange and the adjacent part of the web may be provided with openings to receive a fastening bolt. The blanking plates are preferably provided with detents which interengage to enhance said interlock.

From another aspect the invention consists in an architectural frame with mitred corner joints, including a pair of perpendicular frame members each of sheet metal and of generally channel cross-section, the two members being mitred at adjacent ends and formed to interengage so that after initial assembly at a relative angle of less than 90 subsequent pivotal movement into the 90 position causes tightening of the mitre joint.

A fulcrum for the pivotal movement is provided by a hook shaped bracket on one of the member engaging over the web of the other member.

The invention may be performed in various ways and one specific embodiment will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic front elevation of a door opening through a wall with a door frame installed in the opening, Figure 2 is a sectional plan view on the line Il-Il in Fig. 1, Figure 3 is a perspective view illustrating the upper end of one jamb of the frame before final assembly, Figure 4 is a perspective view of the adjacent mitred end of the head of the frame, Figure 5 is a side view illustrating the initial positions of the two frame members before assembly, and Figure 6 is a sectional view through the jamb and head positioned side by side.

In this example the wall is formed from two plasterboard panels 10 and 11 spaced apart and located on internal metal studs or frame bars 12. In itself this forms no part of the invention. The door frame illustrated includes two jambs 14, 16 and a horizontal head 15 forming two mitred corner joints 17. The individual frame members 14, 15, 16 are preferably attached to the metal studs 12 of the wall by fastening bolts, but the frame is itself a rigid self-supporting structure with tight corner joints.

The three frame members are all formed of sheet steel by a roll-forming process and are of generally channel cross-section, as illustrated, the channel having two side flanges 20, 21, a base web 22 and a deeper central channel 23. The lips of the two side flanges 20, 21 are inturned at 25 and provide clean edge flanges on opposite sides of the door opening, with no sharp edges.

Each of the frame members is cut off on a clean 45 mitre, as illustrated in Figs. 3 and 4. It is difficult to achieve this on a continuous production from a coiled steel strip and the steel is preferably roll formed in the required lengths and cut to the mitre subsequently. The upper end of each jamb is additionally provided with a pair of blanking plates 30, 31 welded to the adjacent side flange 20, 21 and having a corner 32 which projects beyond the line of the mitre. Thus when the two frame members are assembled tightly the mitre joint is effectively closed by the blanking plates close behind.

Each of the blanking plates 30, 31 also has a small dimple or projection 34 to assist in the final assembly as will be described and the two separate parts of the bottom web 22 of the channel are each formed with a small hole 36 for a locking screw.

The adjacent end of the head frame member 15 is also provided with a full mitre, as indicated in Fig. 4. In addition two brackets are welded in position, each bracket including a blanking plate 40 lying parallel with an adjacent side flange 20, 21 and a perpendicu lar integral plate 41 lying flush against and welded to the respective bottom web portion 22 of the channel. Each of these plates 41 has a perpendicular tab or tongue 42 projecting downwardly, out of the channel, with a small hole 43 arranged to align with one of the holes 36 in the other frame member. The plates 40 have dimples or apertures 44 which will register with the dimples 34 when assembly is complete.

For assembly, one of the jambs 14, 16 is initially placed in position against and partly embracing the plasterboard panels of the wall and the head 15 is then offered up with its adjacent mitred and close to the mitred end of the jamb, as shown in Fig. 5. The blanking flanges 32, 40 are arranged in overlap and the tongues 42 are hooked over the bottom web portions 22 on the jamb to provide a fulcrum effect. The head 15 is then rocked upwards and simultaneously pressed in against the top of the jamb 17 thus causing the two frame members to interengage. This rocking movement automatically tightens one against the other so that when in the final perpendicular position the mitred joint is closed tight thus making a rigid self-supporting corner. As the members reach this position; the dimples 34 snap into the concave side of the dimples 44 or the equivalent apertures, further rigidifying the corner. A similar assembly process can be performed on the opposite top corner of the frame by engaging the two mitred corner ends and swinging the jamb 16 downwards into position against the wall.

It will be noted from Fig. 6 of the drawings that the blanking plates 40 on the head member 15 are spaced from the adjacent side flange 20 by a narrow clearance which provides a thin deep pocket 50 of approximately the same width as the thickness of the sheet metal. Thus the opposing blanking plates 30, 31 during assembly are press-fitted into these pockets and in combination with the hooked flanges 42 and the other components of the assembly a very firm rigid corner joint results.

Claims (9)

1. An architectural frame including two adjacent sheet metal frame members each of generally channel cross-section, the frame members being mitred at their ends and formed to engage and interlock, the side flanges of the two channels being mitred on the external surface, but provided with inter nal overlapping blanking plates.

2. A frame according to Claim 1, in which one of the -internal blanking plates is spaced from the adjacent side flange of the channel by a narrow gap approximately equal to the thickness of the blanking plate on the other channel.

3. A frame according to Claim 1 or Claim 2, in which the base web of one of the channels is cut off on the plane of the mitre, but is provided with an additional bracket having a flange arranged to hook over the web of the channel of the other frame member.

4. A frame according to Claim 3, in which the hook flange and the ajdacent part of the web of the other frame member are provided with openings to receive a fastening bolt.

5. A frame according to any preceding claim, wherein the blanking plates are provided with detents which interengage to enhance said interlock.

6. An architectural frame with mitred corner joints, including a pair of perpendicular frame mebmers each of sheet metal and of generally channel cross-section, the two members being mitred at adjacent ends and formed to inter-engage so that after initial assembly at a relative angle of less than 90 subsequent pivotal movement into the 90 position causes tightening of the mitre joint.

7. A frame according to Claim 6, in which a fulcrum for the pivotal movement is provided by a hook shaped bracket on one of the members engaging over the web of the other member.

8. An architectural frame as claimed in any one of claims 1 to 4 and as claimed in Claim 5 or 6.

9. An architectural frame substantially as hereinbefore described with reference to the accompanying drawings.