GB1573888A

GB1573888A - Sub-frame elements for use in building construction

Info

Publication number: GB1573888A
Application number: GB476778A
Authority: GB
Original assignee: Radway Plastics Ltd
Current assignee: Radway Plastics Ltd
Priority date: 1978-02-07
Filing date: 1978-02-07
Publication date: 1980-08-28

Description

(54) IMPROVEMENTS IN OR RELATING TO SUB-FRAM] ELEMENTS FOR USE IN BUILDING CONSTRUCTION (71) We, RADWAY PLASTICS LIMITED, of Radway Road, Shirley, Solihull, West Midlands, a British Company, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- When a metal window frame is fitted into the wall of a building, it is generally necessary to provide a sub-frame surrounding the metal frame. Such a subframe can be made in timber, although this can add considerably to the cost of the metal window frame installation. It has been proposed therefore, to manufacture striplike sub-frame elements from plastics material (for example unplasticised polyvinylchloride -- u.p.v.c.) but since such a sub-frame strip element will generally have to be of hollow construction, for economic reasons, it is difficult to attach other elements such as sills to the subframe. One of the objects of the present invention is to provide a composite subframe element, which is adapted to receive external fittings such as sills.

Another problem which arises with a plastics sub-frame element, is that it is undesirable to have any projecting lips or flanges. because these are easily broken in transport or on the building site. It is another object of the present invention therefore. to provide a composite sub-frame element which has certain projections, but in which the projections are not vulnerable.

According to this invention, a composite sub-frame element for use in building construction comprises a strip element adapted to form the underside of a subframe and grooved on its underside, and a platform element comprising a moulded article having at least one flat-topped arm and a column upstanding from the arm and interengaged with a groove in the underside of the strip element, whereby the platform element is suspended from the strip element and its arm provides a platform beneath the strip element, the arrangement providing a pocket open at one edge between the underface of the strip element and the platform. In effect, a pocket is formed between the underside of the strip element and the arm on the platform element, and this pocket provides a convenient means of attaching members such as sills to the subframe element. Since the platform element is detachable, it may be kept separate from the sub-frame strip element, and only affixed to that element, after the sub-frame has been built into a window opening in a wall. In that way, the projection formed by the arm of the platform element which would be a vulnerable part of the composite sub-frame element, is only attached to the strip element, at a time when it is unlikely to be damaged.

Preferably the underface of the strip element is flat and the top face of the arm is parallel with the underface of the strip element. It is also preferred that the free end of the arm is level with one of the edges of the strip element. In this way, the pocket provided between the underside of the strip element and the arm is generally rectangular, and open at the edge of the strip element. It is also preferred that the top face of the arm is roughened to provide a friction grip surface.

According to a preferred feature of the invention, there are two similar arms extending on opposite sides of the column.

With this preferred arrangement, it will be appreciated that pockets are provided opening on to each edge of the sub-frame element.

Preferably the groove in which the column is engaged is undercut, and the top of the column has formations engaging in the undercut portions of the groove. For example, the top of the column may be a snap-fit in the groove. One way of achieving this is to make the column in two parts, adapted to spring towards each other to provide for the snap fitting. Alternatively, the column may have a head which will only pass through the mouth of the groove when the platform element is in one orientation with respect to the strip element, and becomes engaged in the undercut portions of the groove when the platform element is turned to the orientation which is required in the completed composite element.

Various constructions in accordance with the invention will now be described by way of examples only, with reference to the accompanying drawings, in which: Figure 1 is a transverse section through detail of a wall of a building at a window opening, Figure 2 is a side view of a platform element, Figure 3 is a plan view of the platform element shown in Figure 2, Figure 4 is a perspective view of the platform element shown in Figures 2 and 3, Figure 5 is a cross-section through a subframe strip element.

Figure 6 is a perspective view of an alternative form of platform element, and Figure 7 is a perspective view of a third form of platform element.

Referring to Figure 1, there is shown part of a cavity wall of a building including an outer leaf 10 and an inner leaf 12, with a cavity 14 between them. A sill member 16 of a sub-frame for a metal window frame (not shown) is illustrated in Figure 1 in a position where it bridges the cavity 14. The sill member 16 is made as a plastics extrusion in u.p.v.c., and as shown in Figure 1, it is generally rectangular in cross-section, although it is formed with undercut Tshaped grooves 18 and 20 in its underside. In fact, the sill member 16 may be constructed as described in the specification of our copending United Kingdom Patent Application No: 3581/78.

An extruded plastics sill 22 is fitted to the outside of the sub-frame member 16, and covers the reveal on top of the outer leaf 10 of the wall. The sill 22 shown in Figure 1 is constructed as described in the specification of our co-pending United Kingdom Patent Application No: 3583/78 (Serial No.

1573887). It is not necessary therefore to describe the sill 22 in detail, nor is it necessary to give a detailed description as to how the sill 22 is fitted, since this is all explained in the specification of Patent Application No: 3583/78. (Serial No.

1573887).

A second extruded plastics sill 24 is fitted on the inside of the sub-frame sill element 16, and extends horizontally therefrom, over the top of the inner leaf 12 of the cavity wall, to provide a simulated window board on the inside of the window frame. Again, it is unnecessary to describe the method of fitting the inside sill 24 in detail, since this is also described in the specification of our copending Patent Application No: 3583/78.

(Serial No. 1573887).

It will be noted, that each of the sills 22 and 24 has a scroll formation 26 at the window frame end of its cross-section, and that each of these scroll formations is supported by a platform element 32. The latter is more clearly illustrated in Figures 2, 3 and 4, and is made as a moulding in u.p.v.c. material. The platform member 32 comprises a pair of aligned horizontal arms 38 and 40 extending on opposite sides of an upstanding column 42. Each of the horizontal arms 38 and 40 is formed with a serrated top surface as indicated in Figures 3 and 4, for the purpose of providing a friction surface.

The upstanding column 42 is of the same width as the arms 38 and 40, but is surmounted by an elliptical head 44, the length of which is greater than its width. A shoulder piece 46 is formed in the angle between the column 42 and the underside of the elliptical head 44, and the dimensions of this part of the platform element, are such that the head 44 can fit tightly into either of the grooves 18 and 20 formed in the underside of the sill member 16 when the platform element is so orientated relatively to the sill member 16, that its arms 38 and 40 extend transversely of the sill element (i.e.

as shown in Figure 1). Furthermore, the size of the shoulder piece 46 is such that when the platform element is so positioned, the outer edge of the shoulder piece 46 engages with the lip formed on that side of the groove 18 or 20 into which the platform element is secured. Now it will be apparent, that it is impossible to push the head 44 into the groove 18 or 20, when the platform element is orientated as shown in Figure 1, but the arrangement is such, that if the platform element is turned through 90" about a vertical axis, so that its arms 38 and 40 extend longitudinally with respect to the sill member 16, then it is possible for the head 44 to pass through the mouth of the appropriate groove 18 or 20, and when the top of the head engages with the bottom of the groove, then the platform element can be turned back through 90" to the position shown in Figure 1, and this will exercise a locking effect, whereby the head 44 becomes secured in the groove. In this position, the platform element is suspended from the underside of the sill member 16.

In a refinement which is not illustrated in the drawings, the head 44 may be formed with flats at its ends, and of such dimensions that these flats engage with the ends of the undercut portions of the groove when the platform element is fitted to the sill member 16. This means that the walls of the groove will be slightly distended by the head 44 as it is approaching the position shown in Figure 1, but when it arrives at that position, the walls will revert to their original position, and ensure that the platform element is held in the correct transverse orientation relatively to the sill member 16. In practice however, it will generally be obvious whether or not the platform elements are correctly aligned, and in any event, the alignment is not very critical.

When the platform element is in the position shown in Figure 1, it forms a pocket 48 between the underside of the bottom wall of the sill member 16 and the top face of the arm 38, and a similar pocket 50 between the underside of the sill member 16 and the top surface of the arm 40. These pockets receive the scroll formations 26 along the edges of the sills 22 and 24. The friction surfaces provided on the arms 38 and 40 by the small serrations are useful in retaining the scroll formation 26 in the correct lateral position relatively to the sill member 16, when the sills 22 and 24 are being rocked about their scroll ends, as described in the specification of our co-pending Patent Application No: 3583/78. (Serial No. 1573887). It is to be understood, that before a sill 22 or 24 is fitted, a plurality of platform elements 32 will be attached to the underside of the sill member 16 of the sub-frame at spaced apart positions, and generally it will be adequate to fit them at about 30 centimetre spacings.

Figure 5 illustrates an alternative form of sub-frame structural element 90, which can be used as a sill in place of the sill member 16 illustrated in Figure 1. The sill member 90 is also formed as an extrusion in u.p.v.c.

material, so that it is only necessary to illustrate the cross-section in Figure 5, and the construction of this sill member is also described in the specification of our copending Patent Application No: 3581/78.

For present purposes, it is only necessary to refer to the fact that three dovetail-shaped grooves 92, 94 and 96 are provided in the underside of the sill member 90, in place of the grooves 18 and 20 illustrated in Figure 1.

A platform element 98 (see Figure 6) is specially adapted for fitting into one of the grooves 92, 94 and 96, and comprises a single arm 100 having a serrated upper surface 102, which arm is similar to the arm 38 on the platform element shown in Figures 2 to 4. At the inner end of the arm 100, there is a pair of upstanding columns 104 and 106, spaced apart from eath other, and formed with triangular heads 108 and 110 respectively. The arrangement of the heads 108 and 110 is such that they can fit tightly into any one of the grooves 92, 94 and 96. The platform element 98 is fitted to the sill member 90, by nipping together the upstanding members 104 and 106, until the triangular heads 108 and 110 will pass through the mouth of one of the grooves 92, 94 and 96. and the head members 108 and 110 are then pushed upwardly into that groove, and nipping pressure on the columns 104 and 106 is then released allowing the head members 108 and 110 to snap into the recesses of the dovetail-shaped groove. Hence, the platform element 98 is a snap-fit within any one of the grooves 92, 94 and 96, and when fitted acts in the same manner as the platform element 32 illustrated in Figures 1 to 4, excepting that it only provides a single pocket 48 on the outside of the sub-frame. It will be appreciated, that by fitting the platform element pointing in the opposite direction, it is possible to provide a pocket open on the inside of the sub-frame instead of one that is open on the outside.

However, in most instances, if only a single pocket is required, it will be on the outside.

In Figure 7, there is illustrated another form of platform element 112, which also has a single arm 114, so that it is adapted to produce only one pocket on the underside of the sill member 16 or 90. In this construction, there is a pair of upstanding columns 116 and 118 similar to the columns 104 and 106 on the element 98, but the head formations 120 and 122 are round nosed, instead of triangular. In fact, the platform element 112 can be fitted in exactly the same way as the element 98, and can be used with either of the sub-frame sill elements 16 or 90.

Whilst the platform element 32 has been described as being fitted by a turning action, and the platform elements 98 and 112 fitted by a snap-in action, it will be appreciated that any of these elements could also be fitted by sliding along the grooves 18, 20, 92, 94 or 96 from one end of the sub-frame sill element 16 or 90. However, this would mean that the platform elements would have to be fitted to the sill member before construction of the sub-frame, and before building the sub-frame into the wall, and this is undesirable, as it would leave the arms of the platform elements vulnerable.

It is to be understood, that snap-in type fittings as illustrated in Figures 6 and 7 could be used with a two-armed platform element as illustrated in Figures 2 to 4, and conversely, a rotatable fitting as illustrated in Figures 2 to 4 could be used with single arm type platform elements as illustrated in Figures 6 and 7.

The platform element shown in Figures 2, 3 and 4 is also shown in the Specification of Application No: 3583/78. (Serial No.

1573887).

WHAT WE CLAIM IS: 1. A composite sub-frame element for use in building construction comprising a strip element adapted to form the underside of a sub-frame and grooved on its underside, and a platform element comprising a moulded

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Claims

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walls will revert to their original position, and ensure that the platform element is held in the correct transverse orientation relatively to the sill member 16. In practice however, it will generally be obvious whether or not the platform elements are correctly aligned, and in any event, the alignment is not very critical.

When the platform element is in the position shown in Figure 1, it forms a pocket 48 between the underside of the bottom wall of the sill member 16 and the top face of the arm 38, and a similar pocket 50 between the underside of the sill member 16 and the top surface of the arm 40. These pockets receive the scroll formations 26 along the edges of the sills 22 and 24. The friction surfaces provided on the arms 38 and 40 by the small serrations are useful in retaining the scroll formation 26 in the correct lateral position relatively to the sill member 16, when the sills 22 and 24 are being rocked about their scroll ends, as described in the specification of our co-pending Patent Application No: 3583/78. (Serial No. 1573887). It is to be understood, that before a sill 22 or 24 is fitted, a plurality of platform elements 32 will be attached to the underside of the sill member 16 of the sub-frame at spaced apart positions, and generally it will be adequate to fit them at about 30 centimetre spacings.

Figure 5 illustrates an alternative form of sub-frame structural element 90, which can be used as a sill in place of the sill member

16 illustrated in Figure 1. The sill member 90 is also formed as an extrusion in u.p.v.c.

material, so that it is only necessary to illustrate the cross-section in Figure 5, and the construction of this sill member is also described in the specification of our copending Patent Application No: 3581/78.

For present purposes, it is only necessary to refer to the fact that three dovetail-shaped grooves 92, 94 and 96 are provided in the underside of the sill member 90, in place of the grooves 18 and 20 illustrated in Figure 1.

A platform element 98 (see Figure 6) is specially adapted for fitting into one of the grooves 92, 94 and 96, and comprises a single arm 100 having a serrated upper surface 102, which arm is similar to the arm 38 on the platform element shown in Figures 2 to 4. At the inner end of the arm 100, there is a pair of upstanding columns 104 and 106, spaced apart from eath other, and formed with triangular heads 108 and 110 respectively. The arrangement of the heads 108 and 110 is such that they can fit tightly into any one of the grooves 92, 94 and 96. The platform element 98 is fitted to the sill member 90, by nipping together the upstanding members 104 and 106, until the triangular heads 108 and 110 will pass through the mouth of one of the grooves 92, 94 and 96. and the head members 108 and 110 are then pushed upwardly into that groove, and nipping pressure on the columns 104 and 106 is then released allowing the head members 108 and 110 to snap into the recesses of the dovetail-shaped groove. Hence, the platform element 98 is a snap-fit within any one of the grooves 92, 94 and 96, and when fitted acts in the same manner as the platform element 32 illustrated in Figures 1 to 4, excepting that it only provides a single pocket 48 on the outside of the sub-frame. It will be appreciated, that by fitting the platform element pointing in the opposite direction, it is possible to provide a pocket open on the inside of the sub-frame instead of one that is open on the outside.

However, in most instances, if only a single pocket is required, it will be on the outside.

In Figure 7, there is illustrated another form of platform element 112, which also has a single arm 114, so that it is adapted to produce only one pocket on the underside of the sill member 16 or 90. In this construction, there is a pair of upstanding columns 116 and 118 similar to the columns 104 and 106 on the element 98, but the head formations 120 and 122 are round nosed, instead of triangular. In fact, the platform element 112 can be fitted in exactly the same way as the element 98, and can be used with either of the sub-frame sill elements 16 or 90.

Whilst the platform element 32 has been described as being fitted by a turning action, and the platform elements 98 and 112 fitted by a snap-in action, it will be appreciated that any of these elements could also be fitted by sliding along the grooves 18, 20, 92, 94 or 96 from one end of the sub-frame sill element 16 or 90. However, this would mean that the platform elements would have to be fitted to the sill member before construction of the sub-frame, and before building the sub-frame into the wall, and this is undesirable, as it would leave the arms of the platform elements vulnerable.

It is to be understood, that snap-in type fittings as illustrated in Figures 6 and 7 could be used with a two-armed platform element as illustrated in Figures 2 to 4, and conversely, a rotatable fitting as illustrated in Figures 2 to 4 could be used with single arm type platform elements as illustrated in Figures 6 and 7.

The platform element shown in Figures 2, 3 and 4 is also shown in the Specification of Application No: 3583/78. (Serial No.

1573887).

WHAT WE CLAIM IS: 1. A composite sub-frame element for use in building construction comprising a strip element adapted to form the underside of a sub-frame and grooved on its underside, and a platform element comprising a moulded

article having at least one flat-topped arm and a column upstanding from the arm and interengaged with a groove in the underside of the strip element, whereby the platform element is suspended from the strip element and its arm provides a platform beneath the strip element, the arrangement providing a pocket open at one edge between the underface of the strip element and the platform.
2. A composite sub-frame element as claimed in Claim 1, in which the under face of the strip element is flat and the top face of the arm is parallel with the under face of the strip element.
3. A composite sub-frame element as claimed in Claim 2, in which the free end of the arm is level with one of the edges of the strip element.
4. A composite strip element as claimed in any one of Claims 1 to 3, in which the top face of the arm is roughened to provide a friction grip surface.
5. A composite sub-frame element as claimed in any one of Claims 1 to 4, in which there are two similar arms extending on opposite sides of the column.
6. A composite sub-frame element as claimed in any one of Claims 1 to 5, in which the groove in which the column is engaged is undercut and the top of the column has formations engaging in the undercut portions of the groove.
7. A composite sub-frame element as claimed in Claim 6, in which the top of the column is a snap-fit in the groove in the strip element.
8. A composite sub-frame element as claimed in Claim 7, in which the column is in two parts adapted to spring towards each other to provide for the snap fitting.
9. A composite sub-frame element as claimed in Claim 6, in which the column has a head which will only pass through the mouth of the groove when the platform element is in one orientation with respect to the strip element and becomes engaged in the undercut portions of the groove when the platform element is turned to the orientation which is required in the completed composite element.
10. A composite sub-frame element as claimed in any one of Claims 1 to 9, in which the strip element is constructed as claimed in any one of Claims 1 to
11 of United Kingdom Patent Application No: 3581/78.

I 1. A composite sub-frame element as claimed in any one of Claims 1 to 10, in which the platform element is made in plastics material.
12. A composite sub-frame element as claimed in any one of Claims 1 to 10, constructed and arranged substantially as herein described with reference to Figures 1 to 4 of the accompanying drawings.
13. A composite sub-frame element constructed and arranged substantially as herein described with reference to Figures 5 and 6 or Figures 5 and 7 of the accompanying drawings.