GB2230811A

GB2230811A - Window sealing strips

Info

Publication number: GB2230811A
Application number: GB9007485A
Authority: GB
Inventors: John Lenz
Original assignee: Linear Ltd
Current assignee: Linear Ltd
Priority date: 1989-04-05
Filing date: 1990-04-03
Publication date: 1990-10-31
Also published as: EP0391700A2; EP0391700A3; GB9007485D0

Abstract

A window sealing strip is for use in wooden windows where a fixed frame receives a hinged leaf has a root 16 a base 15 and a flipper seal 17 and is to be mounted on the fixed frame 11 with the flipper seal engaging the moveable leaf 12. The majority of the strip is extruded from a rigid PVC plastics material. However, the portion 17c of the flipper adjacent the base, and, optionally, the nose of the flipper and a projection 16c on the root are all made from a plastics material which is more resilient than the PVC plastics material, eg urethane plastics. The flexible hinge 17c gives the flipper seal excellent compression set performance. <IMAGE>

Description

WINDOW SEALING STRIPS The invention relates to window sealing strips for sealing gaps in wooden windows between a fixed frame and a hinged openable leaf, for the prevention of draughts.

One proposal for sealing such gaps takes the form of a elongated sealing strip having a base from which depends a root received in a channel cut in the fixed frame and having a portion extending from the base, engaging the window leaf as the leaf is closed into the frame and then bearing resiliently against the closed leaf to seal the gap. Sealing strips of this kind can be made of extruded plastics material or from a shaped foamed plastics material, perhaps with an impervious plastics cover.

A problem with both these known types of sealing strips is their bulk (i.e. their height in a direction normal to the base in a direction opposite the root). In order to achieve the required resilient performance in extruded sealing strips, the plastics material of the strip is necessarily comparatively thick and foamed plastics materials are also necessarily comparatively thick if sufficient resilience is to be achieved. For this reason, it is currently necessary to design a window to accommodate a particular sealing strip so that there is a sufficient gap between the relevant parts of the fixed frame and the hinged leaf to accommodate the base and 1 the compressed resilient portion. This is disadvantageous because it constrains window design and prevents sealing strips being fitted to windows which have not been designed to accommodate them.

According to the invention, there is provided a sealing strip for wooden windows in which a fixed frame receives a hinged window leaf, the sealing strip comprising an elongate base having two sides, a root depending from one side of the base for receipt in a channel in the fixed frame to mount the sealing strip on the fixed frame and a flipper seal extending from the other side of the base for sealing engagement with the window leaf, the sealing strip being extruded with the majority of the sealing strip being of a PVC material but with a portion of the sealing strip between the base and the flipper seal being of a plastics material that is more resilient than the PVC material for reducing the set of the flipper seal after compression.

By making the base and the root of a rigid plastics material, their dimensions ,can be very compact indeed.

The more resilient plastics winge between the flipper seal and the base allows it to have a resilience that is maintained throughout its useful life and also allows it to have compact dimensions. Thus the whole sealing strip is compact and so does not require the window to be designed around the sealing strip - rather the sealing strip can be fitted to any wooden window.

Preferably, the flipper seal has a free edge which is also formed from said more resilient plastics material.

The roof may include at least one side projection of said more resilient plastics material.

The following is a more detailed description of an embodiment of the invention, by way of example, reference being made to the accompanying drawing which is a cross section through a window frame in which a sealing strip is mounted on a fixed frame member. Referring to the drawing, the sealing strip 10 is mounted in a wooden window formed by a fixed frame 11 and a hinged leaf 12. The hinged leaf may be side or centre hung to pivot about a vertical axis or top or centrally hung to pivot about a horizontal axis.

Alternatively, the strip may be appied to windows and doors in which a sliding leaf is received in a fixed frame or in which the leaf moves relatively to the frame via a tilt and turn mechanism.

The fixed frame is provided with a rebate 13 having a vertical surface 13a against which the moveable leaf 12 bears, when closed, and a surface 13b at right angles to the vertical surface 13A and parallel to a surface 14 of the moveable leaf 12, when the leaf is closed into the fixed frame 11. The sealing strip 10 is mounted on the surface 13b.

The sealing strip 10 comprises a base 15, a root 16 depending from one side of the base and a flipper seal 17 extending from the other side of the base. The free end of the flipper seal 17 is provided with a nose 18.

The root 16 has two projections 16a, 16b to one side and a single, longer, projection 16c to the other side.

The sealing strip 10 is extruded from two different plastics materials. The majority of the sealing strip 10, other than the longer projection 16c, the nose 18, and the portion 17a of the flipper adjacent the base 15, are formed from a relatively rigid PVC material.

The longer projection 16c, the nose 18 and the flipper portion 17a are formed from a more resilient plastics material such as a urethane plastics material. The dimension T may be 0.445mm to 0.60mm.

In use, the sealing strip 10 is mounted on the fixed frame 11 by insertion of the root 16 into a channel 19 formed in the rebate 13. Due to the very compact dimensions of the sealing strip 10, it is not necessary to enlarge the gap between the surfaces 13b and 14 to accommodate the sealing strip 10. Further, the resilience of the longer projection 16c allows the root 16 to be accomodated in channels 19 of widely varying widths.

As the leaf 12 is closed into the fixed frame 11, the surface 14 on the leaf 12 contacts the flipper seal 17 and depresses it, with the resilience of the flipper seal portion 17a maintaining contact between the seal 17 and the surface 14. Thus, when the leaf 12 is fully closed into the rebate 13, the flipper seal 17 seals the gap between the surfaces 13b and 14 and prevents the passage of air between those parts, so reducing draughts.

Timber surfaces are usually irregular rather than perfectly flat. In addition, timber usually moves or changes shape with varying conditions such as those caused by seasonal changes., The more resilient nose 18 enables the seal to form itself flexibly to the contours of the mating surface, forming a good seal. A more rigid material would be likely to bridge across high points leaving gaps for air to penetrate, allowing gaps to occur.

One important parameter in the performance of sealing strips, is the long term resilience of the sealing strip. In order to give adequate performance over a considerable length of time, it is necessary that the overall height of the sealing strip (that is to say the height from the base to the end of the seal in a direction normal to the base) be maintained substantially constant over a period of time - because if this height reduces, then the effectiveness of the seal is likely also to reduce.

One way of testing such long term effectiveness is to measure the "compression set" of a sealing strip by holding the sealing strip compressed for a period of time (for example 24 hours) at a particular temperature and then removing the compression, allowing the sealing strip to become uncompressed, measuring the height and comparing it with the original height. Any different in these heights is the "qompression set" and plainly the smaller the "compression set" of a sealing strip the better the long term performance of the sealing strip.

EXAMPLE 1 In this example, the samples were tested of four commercially available extruded sealing strips (EXTRUDED 1, EXTRUDED 2, EXTRUDED 3, EXTRUDED 4), a sealing strip of foamed plastics material (FOAMED 1) and a sealing strip in accordance with the invention (INVENTION). The normal height, the fully compressed height and the deflection of the seal were all measured. Then all the samples were fully compressed and kept at -200C for 24 hours. The pressure was then removed and the samples kept at -10 C for 30 minutes and the height of the sealing strips was then again measured. The samples were then tested in the same way at +230C.The results were as follows: -10 C SEAL A P C D E t G Normal Fully Deflection Height Compre- Thick Height Comp (mm) After A-O ssion ness (mm) Height Test Set s (T) (mm) (INn) (mm) Extruded 1 5.02 1.89 3.13 3.56 1.46 46.88 0.9-1.1 Extruded 2 5.86 1.83 4.03 3.87 1.99 49.39% 0.8-0.9 Extruded 3 7.31 2.91 4.40 5.55 1.76 40.1% 0.9-1.1 Extruded 4 7.73 2.70 5.03 6.81 0.92 18.3% INVENTION 6.27 1.40 4.87 6.10 0.15 3.4% 0.45-0.6 Foamed 1 6.56 2.50 4.06 6.41 0.15 3.7% +230C SEAL A B C D E F Normal Fully Deflection Height Compre Height Comp (mm) After A-0 ssion (mm) Height Test Set % (mm) (mm) Extruded 1 5.09 1.90 3.19 4.86 0.23 7.1% Extruded 2 5.13 2.01 3.12 3.72 1.41 45.3% Extruded 3 7.88 2.88 5.00 6.55 1.33 26.6% Extruded 4 7.84 2.96 4.88 7.04 0.80 16.5% INVENTION 6.27 1.40 4.87 6.11 0.16 3.4% Foamed 1 6.52 2.75 3.77 6.30 0.22 6.1% It will be seen that the of the sealing strip of the INVENTION offers very thin seal (column G) with a good range of delection (column C) and excellently low compression set (column F), particularly in comparision with other extruded strips.

Claims

1. A sealing strip for wooden windows in which a fixed frame receives a hinged window leaf, the sealing strip comprising an elongate base having two sides, a root depending from one side of the base for receipt in a channel in the fixed frame to mount the sealing strip on the fixed frame and a flipper seal extending from the other side of the base for sealing engagement with the window leaf, the sealing strip being extruded with the majority of the sealing strip being of a PVC material but with a portion of the sealing strip between the base and the flipper seal being of a plastics material that is more resilient than the PVC material for reducing the set of the flipper seal after compression.

2. A sealing strip according to claim 1 wherein the flipper seal has a free edge which is also formed from said more resilient plastics material.

3. A sealing strip according to claim 1 or claim 2 where the root includes at least one side projection of said more resilient plastics material.

4. A sealing strip according to any one of claims 1 to 3 wherein the more resilent plastics material is a urethane plastics material.

5. A sealing strip substantially as hereinbefore described with reference to the accompanying drawings.