IE45081B1 - Improvements relating to frames for windows or doors - Google Patents

Description

This invention relates to frame constructions for windows, doors and the like and is particularly, though not exclusively, concerned with the provision of sub-frames intended to be fitted around a main frame. A sub-frame is a rectangular frame structure formed of a plurality of frame members joined together and designed to be located between the main frame and the surrounding brickwork, masonry or other wall constructions. The invention may however also be applied to constructions in which the main frame is in effect combined in one with the sub-frame. The invention is principally applicable to domestic as opposed to industrial buildings Xt is generally accepted that a metallic main window frame cannot easily and satisfactorily be installed, or replaced, in a window opening of a brick wall for example, without some form of sub-frame surrounding the main frame. There are practical difficulties in locating a metallic main frame directly • in a brick window opening, particularly if the wall is of hollow cavity construction, and in addition problems can arise from the lack of thermal insulation between =24SS81 the brickwork and the metallic frame, and consequent condensation. One generally accepted procedure is to . provide a timber sub-frame surrounding the main metallic frame, and these timber sub-frames are often constructed of hardwood since at least part of the sub-frame will be exposed and Visible. This in turn creates problems, particularly for do-it-yourself installation, since the hardwood is difficult to saw or drill on site, it is now very expensive, it requires surface finishing and maintenance after installation, joints between the sub-frame members are not easy to construct, and difficulties are also met .in installing such a sub-frame in a water-tight manner in a brick wall opening. Sub-frames of other materials such as metal or rigid plastics would present equal or <·νι-η urosl'-r problems, being extremely difficult und laborious io work ·>η silo, and inconvenient for forming corner joints.

The invention is particularly applicable to the replacement of old window and door frames, either for aesthetic purposes or to cure structural defects.

When an old frame is removed from a wall an irregular opening is left and when inserting a new metallic frame it is of advantage to fit a non-metallic surrounding sub-frame. For the reasons stated metallic and timber sub-frames suffer from serious practical disadvantages.

A particular advantage of the combination frame or subframe construction of the present invention is ihat it is maintenance free, requires no painting, is thermally insulating, and proof against moisture and condensation, and importantly frames or sub-frames of this material 3can be readily cut, sawn, drilled, screwed and joined, *» and can also be stored, if necessary in the open, without loss of shape or deterioration. By comparison timber frames are prone to warp or distort, and cannot be stored in the open.

Accordingly it is an object of the invention to provide an improved frame or sub-frame construction which will be relatively inexpensive and will ease the construction and installation problems.

Broadly stated from one aspect the invention consists in a sub-frame for surrounding a main frame of a window or door, comprising a plurality of separately formed rigid sub-frame members joined together at the cornerSof the frame by means of reinforcing corner cleats, and each formed of a foamed or cellular rigid synthetic plastics material, with an integral relatively dense surface layer or skin of the same synthetic plastics composition.

According to a preferred feature of the invention the frame may include a thin metal covering element or extension piece attached to at. least one of the members.

In a particular preferred construction each frame member has a cross-section providing a main web portion, at least two outwardly extending spaced flanges constituting an open channel, and at least one inwardly extending shoulder or flange providing a locating surface for a main frame.

The invention may be applied to a sub-frame for surrounding and locating a main frame of a window or door, and .also locating an additional or subsidiary frame or panel, the frame having at least one transverse frame -4· •^5081 member of channel cross-section, and including a further cover piece located over the mouth of the channel.

The invention may be performed in various ways and one specific embodiment with a number of possible modifications will now be described with reference to the accompanying drawings in which:Figure 1 is a sectional elevation through a window frame with a surrounding sub-frame in accordance with the invention, Figure 2 is a similar section through another window frame construction according to. the invention, Figure 3 is a section through another form of cill for a sub-frame according to the invention, Figure 4 is a similar section through yet 15 another form of cill for a sub-frame according to the invention designed for universal application to doors, windows and patio doors, Figure 5 is another section through a further modified form of cill for a sub-frame according to the invention, Figure 6 is a fragmentary exploded perspective view illustrating one form of corner joint for a subframe according to the invention, Figure 7 is a vertical section through 25 another frame member according to the invention, forming the cill of a combination main frame and sub-frame, with the usual aluminium main frame omitted, and the glazing panels fixed directly in the frame, and Figure 8 is a similar view to Figure 6, showing a preferred alternative corner joint. -5Referring first to Figure 1, the main frame for the window consists of an upper head section 10 and a lower bottom rail section 11, both formed of extruded aluminium, and arranged to provide support for the glazing 12. In addition of course this main frame includes vertical jambs at both sides. The surrounding sub-frame comprises an upper head member 15 and a lower cill 16, again with vertical jambs at both ends, all four members being joined at the corners by corner cleats as illustrated in Figures 6 or 8. All four members are somewhat wider horizontally than the main frame, and designed to fit within a double hollow cavity brick wall window opening 18. The four frame members of the subframe are provided with inwardly directed locating flanges or shoulders 17 to locate the main frame.

The component members of tho sub-frame are formed of a rigid foamed PVC (polyvinylchloride) plastics material which is of light weight and is specially formed with an integral external dense surface layer or skin also of the same plastics composition, polyvinylchloride but of non-cellular consistency. The upper head 15 is of generally channel shape as illustrated, with a web 9 and two outwardly directed flanges 8, and compared With a member of solid cross-section of the same external dimensions in profile this results in a reduction in volume of approximately 40%, The open {. channel 19 faces upwards, or outwardly from the centre of the frame, and also provides a hollow cavity between the main frame and the brickwork above the window opening, whieh further increases the thermal insulating effect. The bottom cill 16 is also of open channel construction with a downwardly facing channel mouth 20, and in addition a projecting cill element 21, which is of inverted channel construction in this embodiment. Here again the total saving on material compared with a Solid cross-section of the same external dimensions is approximately 40% to 45%.

The foamed PVC material is light in weight and can be very easily machined, sawn or drilled, and rigid connections can be made direct to the main frame and to adjacent'sub-frame members by means of simple angle cleats and by driving screws through the base or web 9 of the open channels, for example where indicated at 22. The external dense skin provides an excellent weather15 resistant surface which does not require painting or other maintenance and the foamed PVC material itself has excellent thermal insulating properties.

The construction illustrated in Figure 2 is designed tc provide a complete frame and sub-frame assembly for a replacement window. The sub-frame is in most respects similar to that of Figure 1, but the head 30 and jambs (not shown) are simple channel section members having a web 9 and flanges 8, but without the locating flange 17 of Figure 1, and the main frame 31 is formed with a flange 32 which abuts against the external face of the sub-frame. The cill 33 of the sub-frame also omits the locating flange 17 of Figure 1, and is formed with a step or shoulder 34 to be engaged by the flange 32 on the main frame. The projecting cill portion 35 is similar to that of Figure 1 but displaced -7somewhat downwardly. In other respects this is similar to the Figure 1 construction.

The construction illustrated in Figures 1 and 2 may readily be adapted to provide a replacement frame for double sliding patio doors. For some purposes each sub-frame member may include a cover plate designed to fit over the open mouth of an open channel, to form a closed or hollow construction.

The cill illustrated in Figure 3 is essentially similar to that of Figure 1, but the projecting cill 46 is of hollow cross-section and the inclined part of the cill is provided with grooves to locate an aluminium threshhold strip 45, for use when incorporated in a door frame or patio door assembly. When used as a window frame this threshhold strip may be omitted.

Figure 4 illustrates another foamed PVC cill sub-frame member where the main component 26 is similar to the head member 15 of Figure 1, but is formed to receive (if required) a variety of optional extensions. One possible extension is a channel shaped aluminium extrusion 48 having inturned lips 49 to locate in grooves in the member 26. This provides a sloping cill extension similar to the extension 21 of Figure 1. Alternatively, a modified aluminium extrusion 50 may be fitted, with an upper inclined surface 51 at a lower level, providing the equivalent of the Step or shoulder 32 in Figure 2. In lieu of aluminium extrusions, solid or foamed PVC extension members may be used. This construction allows all four members of the sub-frame to be of the same cross-section, the cill having -33 ί» Ο 81 the appropriate extension piece fitted as required.

Figure 5 illustrates a further embodiment where the cill 36 of the sub-frame is of closed hollow profile, with or without an internal web 47, as opposed to the open channel construction of the other examples described.

Figure 6 illustrates one form of corner joint between the head and jamb of a sub-frame, including a steel angle cleat having two perpendicular limbs. The web 9 of the head 15 is cut back at 55 to receive the cleat, one limb 56 being secured to the top surface of the web by countersunk fastening screws driven upwards through the web into tapped holes 57 in the limb. The other vertical limb 58 is similarly secured to the web of the jamb. Further fastening screws 59 are also driven downwards through the web of the head member 15 into the thickened portions of the jamb section. The cleat is then fully concealed from the interior of the frame, and there are no internal or external projections, and a minimum of operations are required.

The frame section illustrated in Figure 7 is a one-piece member designed to act as a combination main frame and sub-frame. The member 60 is formed of foamed PVC with an integral dense non-cellular PVC skin as described above and is a generally open channel section, as illustrated, with a web 9 and two flanges 8, and an upstanding flange 61 acting as an abutment for the glazing 62, v/hich is held in position by a resilient snap-in glazing bead 63 conveniently formed of aluminium. The flange 61 and the bead 63 are also formed to locate resilient dry glazing sealing strips 64. ι The same frame section may be used in combination with an opening window or ventilation frame, preferably formed in aluminium and designed to receive and locate a glazing panel, again with a removable resilient beading and dry glazing sealing strips.

. Figure 8 is a perspective view corresponding to Figure 6 illustrating another, and preferred, form of corner joint, which is particularly useful at the bottom corners where the jambs connect to the cill.

The joint construction illustrated in Figure 8 differs from that of Figure 6 in the use of a steel cleat 71 of a different design and so arranged that the cill 70 runs horizontally throu Reference is drawn to ,s.

Patent No. 45080 .

Patent has been'divided. from which this -10a 3 0 81

Claims (11)

1. a 3 0 81

1. A sub-frame for surrounding a main frame of a window or door, comprising a plurality of separately formed rigid sub-frame members joined together at the 5 corners of the frame by means of reinforcing corner cleats, and each formed of a foamed or cellular rigid synthetic plastics material, with an integral relatively dense surface layer or skin of the same synthetic plastics composition. 10

2. A sub-frame according to claim 1, in which the cross-section of at least one of the sub-frame members at each corner is of hollow or channel shape, and the corner cleat has a limb extending into the interior * of the hollow or channel member. 15

3. A sub-frame according to claim 1 or claim 2, - i in which the corner cleat has a flat plate-like clement which is secured to a flat face of one of the sub-frame members.

4. A sub-frame according to any of claims 1 to 3, 20 including a thin metal covering element or extension piece attached to at least one of the frame members.

5. A sub-frame according to claim 4, in which the metal covering element is attached to the lower horizontal member or cill of the frame. 25

6. A sub-frame according to claim 4 or claim 5, in which the metal element is an extension and has formed lips to key into grooves in the respective frame member.

7. A sub-frame according to any of the preceding claims, in which each frame member has a cross-section 30 providing a main web portion, at least two outwardly extending spaced flanges constituting an open channel, •11· and at least one inwardly extending shoulder or flange providing a locating surface for a main frame.

8. A sub-frame according to any of the preceding claims, for surrounding and locating a main frame of a window or door, and also locating an additional or subsidiary frame, or panel, including at least one transverse frame member of channel cross-section, and including a further cover piece located over the mouth of the channel.

9. A sub-frame according to any of the preceding claims, in which each of the frame members has an inwardly projecting flange or shoulder, providing a locating surface for the associated main frame, and an outwardly directed flange, to assist in locating the sub-frame within an opening in a wa11.

10. A sub-frame according to any of the preceding claims, in which the frame members are formed of foamed polyvinylchloride.

11. A frame construction for a window or door, including a main rectangular frame, formed principally of metal frame member^ and a surrounding sub-frame, as defined in any of the preceding claims.