GB2310240A - Butt joint of a sliding door frame, with a sealing sheet and an intermediate member sandwiched between the abutted members, forming a drainage channel. - Google Patents

Description

"BUILDING FRAME CONSTRUCTION" This invention relates to building frame construction and in particular door and window frame construction.

In modern door and window construction lightweight materials such as aluminium or plastics are used to provide an attractive and durable finish. Both of these materials may be extruded to enable a wide variety of different sections to be created to suit the particular requirements. Because these materials can be of lower strength than traditional materials - wood and steel - the size of the sections used to give sufficient strength for the frames can be aesthetically unattractive. To enable smaller sections to be employed inserts1 usually of steel, are fitted to strengthen the sections. These inserts, being usually totally enclosed are subject to corrosion should any moisture find its way to the steel.

In the construction of the window itself practice at the corners of the frame varies according to the material being used. Aluminium windows generally follow conventional practice used for wood frames, namely butt-jointing using tenons or dowels; in the aluminium version, screws are usually used in place of tenons. Plastics window frames, by contrast, are normally mitre-jointed at the corners and joined by welding, a technique which1 if done well, produces an aesthetically attractive joint.

The difficulty with mitre joints is that they require some skill to produce neat joints; it is quite difficult to mask small errors in cutting. Also, the sealing of the corners against ingress of moisture can be tricky and not always successful, leading to corrosion of any steel inserts. Also mitre joints are not always the aesthetically most attractive joint to use where the width of the frame sections joining at the corner is different. In such a case the normal mitre angle of 45" is replaced by some other angle which can have quite an unattractive appearance.

The present invention provides a new form of comer construction for such frames which can be used for both aluminium and plastics frames. The joint is basically a butt joint but, according to the invention, a sheet of sealing material is placed between the frame components being joined so that, once joined, the sheet of sealing material is sandwiched between the frame components. Where, as is usual, the frame components are hollow, the sheet of sealing material acts to completely seal the hollow interior from outside, thus preventing moisture from entering the interior and damaging any strengthening insert which is located there.

The frame components for door and window frames will generally comprise horizontal and vertical lengths of extruded section. A butt joint will generally involve cutting off square one of the components, usually a horizontal component, and butting it up to the inside edge of a vertical component. Screws are passed from the remote side of the vertical component, through the vertical component and into the horizontal component to draw the two components together to effect the joint.

In the preferred form of construction, the sheet of sealing material comprises, or is mounted on, an intermediate member which is sandwiched between the frame components on assembly. This intermediate member is preferably made of a self-supporting material which may either be a rigid material with a separate sheet of sealing material attached thereto, or may be a resilient material which itself has the required sealing properties. In the former case, the intermediate member may be of rigid plastics material, similar to the plastics material used for the frame components, or may be metal, for example, aluminium where the frame components are aluminium. The sheet of sealing material which is applied to such a rigid intermediate member may be any fonn of suitable gasket but gel gaskets, in particular silicone-based gel gaskets, have been found particularly suitable.

The advantage of using an intermediate member, particularly for plastics frames, is that it contains distortion at the end of the section as it is tightened against the adjacent component at the joint. The intermediate component can be arranged to have the identical perimeter shape to the outside sectional shape of the frame component being butted so that, once assembled, the intermediate member is substantially invisible. However it is preferred to make something of a feature of the intermediate member by forming it with a perimeter flange which acts to cover the immediate joint area. This flange can make an attractive feature of the joint but additionally it hides minor misalignments and cutting errors in the frame components. The flange also prevents expansion of the material of the end of the component as it is drawn against the other component during assembly of the joint.

Thus, in its preferred form, the intermediate member/sealing sheet completely seals off the hollow interior of the frame components, thus preventing ingress of moisture to the interior. In the currently preferred embodiment, the sealing sheet is carried on that side of an intermediate member which, when assembled, faces the open end of one of the frame components being joined. The intermediate member is of rigid material which closes off the open end defining one or more closed interior spaces (depending upon the design of the frame component) in at least one of which is located a strengthening insert, for example, of steel.

This type of joint construction is believed to be particularly suitable in constructions where the glazing unit or other panel to be mounted by the frame is located around its perimeter edge in a three-sided slot formed in the frame. Generally speaking modern door and window frame construction has tended to follow a traditional approach of forming an open rebate into which the glazing unit is placed during assembly, fixing of the unit being achieved by using a (usually) triangular-section fillet which is fixed around the frame to, in effect, take the place of putty in the traditional joining system.

Recently attention has been directed towards methods of construction which do not use these fillets and in which the frame is formed with a full three-sided slot for receiving the panel instead of the open rebate. This eliminates the need for an extra component - the fillet - and simplifies construction. It also makes it easier to seal the joint between the frame and the panel at the comers. In addition, it is easier to make an aesthetically acceptable comer joint.

In this type of construction, draining of the slot can be a problem, particularly the bottom slot into which the remaining slots drain.

This problem is solved by the construction of the present invention because the bottom frame component has its ends cut off square, and the intermediate member closes off the end leaving it substantially square.

When, during assembly, the end of the bottom component is brought against an adjacent upright component, a conduit is defined between the three-sided slot forming the glazing channel of the upright on the one hand and that side of the intermediate member remote from the bottom frame component on the other hand. Thus, provided that the intermediate member is shaped to follow the three-sided slot in the bottom frame component, any liquid which finds its way into the slot in the bottom component will spill over the edge defined by the intermediate member and will enter the aforesaid conduit.

It is thus an important feature that the bottom of this conduit is left open so that liquid entering the conduit can drain away. Likewise, it is desirable that the top of the corresponding conduit formed by the joining of the top frame component to the upright component is also open to atmosphere to provide a vent to prevent syphonage.

In the preferred embodiment of the invention the upright member is capped by end caps which have apertures communicating with said conduits so as to allow liquids to pass through and/or to provide a vent facility.

In order that the invention may be better understood various embodiments thereof will now be described by way of example only and with reference to the accompanying drawings in which: Figure 1 is a diagrammatic perspective view of a typical door/window frame arrangement of the type with which the present invention is concerned; Figure 2 is an exploded perspective view of the joint between the bottom rail and locking stile in the frame arrangement of Figure 2; Figure 3 is a view similar to Figure 2, but taken from a different direction and showing the bottom closing cap.

Figure 4 is a view similar to Figure 3 but shows the joining of the top rail to the locking or closing stile; Figure 5 is a view similar to Figure 4 but showing the joining of the top rail to the meeting stile; Figure 6 is a view similar to Figure 3 but showing the joining of the middle rail to the locking or closing stile; and Figure 7 is an exploded perspective view of the joint between the head member of the outer frame of the frame arrangement of Figure 1, and the jamb.

Referring firstly to Figure 1 there is shown an exemplary sliding door assembly which is provided in order to illustrate the locations of the joints to be described below.

The assembly comprises an outer frame comprising a rectangular frame of four elongate members, each formed as an extrusion of plastics material such as PVC: a horizontal head member/and horizontal cill member 2, and left and right-hand vertical jamb members 3,4.

The door comprises a sliding part 5 and a fixed part 6 each of which have generally similar components and joints. The sliding part 5 comprises a rectangular frame supporting a single double glazed unit 7.

The frame comprises a horizontal top rail 8, and bottom rail 9, and a vertical locking stile 10 and meeting stile 11. The fixed part 6 comprises a rectangular frame comprising a horizontal top rail 12 and bottom rail 13, and left and right vertical stiles 14,15 respectively. In addition a horizontal middle rail 16 divides the frame into upper and lower sections each supporting a respective double glazed unit 17,18. The components of the door likewise comprise elongate extrusions of plastics material such as PVC. The middle rail 16 in this case carries a letter box 19. A handle 20 permits the sliding part 5 to be moved backwards and forwards to gain access to and from the interior of the property. The sliding part may be locked by means (not shown) to the outer frame.

The present invention is primarily concerned with the joints between the components. Figures 2 and 3 illustrate a typical joint between the locking stile 10 and the bottom rail 9 of the opening part 5 of the door. The particular sections used for the stile and rail components are typical of those currently in use in the industry. In particular it will be noted that the section defines a three-sided slot 21 fitted with resilient seals 22 and into which the glazing unit (not shown) is slotted during assembly.

In addition both sections have a hollow interior chamber 23 in which is located a square section hollow steel reinforcing bar 24. The bar in the bottom rail is formed with two axially extending apertures 25 which receive fixing screws 26, as will be described in more detail below.

Located between the components to be jointed is an intermediate member 27 in the form of a flat plate of plastics material such as PVC . As can be seen, the exterior shape of the member 27 conforms generally to that of the exterior of the bottom rail 9, but a flange 28 is formed around the perimeter, as shown, this flange extending both above and below the general plane of the plate forming the member 27.

The flange does not extend across the top edge 29 of the plate, and it will be further noted that, out of this top edge 29 is formed a slot 30 which is intended to correspond in size and shape with that of the slot 21 in the bottom rail 9. Thus, once assembled, the edge of the slot 30 forms a continuation of the slot 21.

A sheet 31 of sealing material is attached to that face of the intermediate member 27 which faces the open end of the bottom rail 9 and acts, when the joint is assembled, to seal the interior chamber 23 against ingress of moisture. The sheet 31 can cover the whole area of the plate, but this is not considered necessary since it is the chamber 23 (where the reinforcing bar is situated) which most requires sealing. The sheet of sealing material can be made of any suitable resilient sealing material, but the product known as Raychem GelTek (Trade Mark) has been found particularly suitable.

In order to form the joint, the locking stile 10 and bottom rail 9 are cut off square at surfaces 32,33 respectively. The components are now brought together as shown in Figures 2 and 3, and screws 26 are screwed through the locking stile 10 and intermediate member 27 into the apertures 25 found in the reinforcing bar 24 to firmly attach the locking stile 10 and bottom rail 9 together, with the intermediate member 27 sandwiched in between. The flange 28 on the intermediate member 27 covers the raw edges of the joint between the two components and hides any imperfections in the cutting of surface 33.

A closing cap 34 having the shape shown in Figure 3 is attached at the bottom end of the locking stile 10. This cap likewise has a perimeter flange to provide a similar visual effect to the flange 28 of intermediate member 27 and also to disguise any imperfections in the cutting of surface 32. A further sealing sheet 39, similar to sheet 31, is attached to cap 34 and seals the bottom end of the chamber 23 in the locking stile 10. The closing cap 34 further has an aperture 35 which is in alignment with the slot 21 in the locking stile 10.

It will be seen that, when assembled, the intermediate member 27 forms, with the slot 21 in the locking stile 10, a vertical conduit having a bottom outlet opening in the form of the aperture 35 in the closing cap 34. The purpose of this conduit is to receive liquid which has found its way into the bottom of the slot 21 in the bottom rail 9. Such liquid will flow over the weir formed by the bottom edge of slot 30 in the intermediate member 27 and escape to the exterior via the aperture 35; likewise any liquid originating in the slot 21 of locking stile 10 itself or in the slot 21 of the top rail 8 (as will be explained in more detail later) will be drained by the same route.

Reference is now made to Figures 4 and 5 which show the joint between the top rail 8 and locking stile 10 (Figure 4) or meeting stile 11 (Figure 5). Most of the construction will be selfevident after studying the explanation given above of the joint of Figures 2 and 3. The main differences are in the different cross sectional shape of the top rail 8, as against the bottom rail 9. As can be seen, this results in the shape of the intermediate member 27 being different; however the principles are the same, and detailed explanation is felt to be unnecessary. It will be seen that the lockingimeeting stile 10/11 is equipped with a top closing cap 36 which is of similar shape to closing cap 34 and has a similar aperture, reference 37, for venting purposes. Thus in the unlikely event that moisture gets trapped in the slot 21 of the top rail 8 or locking rail 10, it will be drained away.

Reference is now made to Figure 6 which shows the joint between the left-hand stile 14 of the fixed part 6 and the middle rail 16.

Once again the construction should be apparent from the previous explanation. The main difference from previouslytescribed constructions is that the horizontal rail 16 is effectively doubled in the sense that it has two interior chambers containing strengthening bars 24 and two slots 21, one for the upper unit 17 and one for the lower unit 18 (Figure 1). It will be noted that the sealing sheet 31 spans both chambers 23, but two separate sheets could be used.

The pillars 37 formed on that surface of the intermediate member 27 remote from the rail 16 and through which the screws 26 pass are intended to prevent the material of the stile 14 from collapsing as the screws are tightened up during assembly of the joint. Although not shown, similar pillars could be used in the above-described embodiments or separate collars, slipped into the screws during assembly, could be used for the same purpose.

Reference is now made to Figure 7 which illustrates the top right comer joint of the outer frame of Figure 1. Thus the joint is formed between the right-hand end of the horizontal head member 1 and the righthand vertical jamb member 4. In this case an L-shaped intermediate member 40 us used. The shape of the member is apparent from the drawings; in particular, it will be noted that it is equipped with a flange 41 serving an equivalent purpose to the flange 28 of intermediate member 27.

A sheet 42 of sealing material, equivalent to sheet 31, is sandwiched between the open top end of the jamb member 4 and serves, as before, primarily to seal the chambers in which are situated the jamb reinforcing bar 24. A similar sealing sheet 43 acts to seal the right-hand end of the head member 1. Screws 26, passing through pillars 37 on the intermediate member, act to fasten the components together to effect a secure joint.

Claims (12)

1. A building frame comprising a plurality of hollow elongate members which are joined together to form the frame using joints including butt joints, and wherein a sheet of sealing material is sandwiched between the butted surfaces of the components of the butt joints in such a way as to seal the open ends of such surfaces.

2. A frame as claimed in claim 1 wherein the sheet of sealing material comprises or is mounted on an intermediate member which is sandwiched between the butted frame members and is made of a selfsupporting material.

3. A frame as claimed in claim 2 wherein said intermediate member is made of resilient material and forms also the sheet of sealing material.

4. A frame as claimed in claim 2 wherein said intermediate member is made of a rigid material to which said sheet of sealing material is attached.

5. A frame as claimed in claim 4 wherein said sheet is applied to one side only of the intermediate member, namely that side which is to face a hollow open end of a frame member, which is to be sealed as aforesaid.

6. A frame as claimed in either one of claims 4 or 5 wherein the sealing material comprises a gel gasket.

7. A frame as claimed in claim 6 wherein the sealing material comprises a silicone-based gel gasket.

8. A frame as claimed in any one of claims 2 to 7 wherein the intermediate member has an external shape which matches that of the section of the frame member being butted.

9. A frame as claimed in any one of claims 2 to 7 wherein the intermediate member has a shape which matches that of the section of the frame member being butted, and is equipped with a perimeter flange which covers the immediate joint area.

10. A frame as claimed in any one of claims 2 to 9 wherein at least one of the frame members carries the panel within a three-sided slot formed on an inwardly-facing surface of the frame member and wherein at least one of said butt joints is formed by butting a frame member against said surface of said at least one frame member1 the arrangement being such that said intermediate member acts as a fourth side to said slot in the area of the joint, thus forming a drainage conduit.

11. A frame as claimed in claim 10 wherein both the frame members forming a butt joint are formed with a three-sided slot as aforesaid, and wherein the intermediate member is shaped to conform with said slot so that liquid present in the slot of the butting frame member can flow away past the intermediate member and into the drainage conduit formed by the drainage member and the slot of the butted frame member.

12. A frame as claimed in claim 11 wherein said butted frame member is intended as a vertical frame member and said butting frame member is intended as a horizontal frame member, and wherein said vertical frame member is equipped with sealing end caps equipped with apertures in the area of the slot to allow for drainage.