GB2339230A

GB2339230A - A weather seal

Info

Publication number: GB2339230A
Application number: GB9814847A
Authority: GB
Inventors: George Ioannou Sergides
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-07-08
Filing date: 1998-07-08
Publication date: 2000-01-19
Anticipated expiration: 2018-07-08
Also published as: GB2339230B; GB9814847D0

Description

2.339230 WEATHER SEAL FOR DOORS, WINDOWS AND THE LUM This invention

relates to weather seals of the kind used e.g. to seal windows and doors against draughts and/or ingress of moisture, and to a method of forming such seals.

Weather seals comprising a resiliently compressible hollow tube 2, see Figure IA, are known. Such seals are located between a door or window and its frame. When the door or window is shut against the frame, the tube is squashed flat (Figure 1B) and recovers its shape (Figure 1A) when the pressure on it is released by opening the door or window. However, the resilience tends to be lost with time and to overcome this it has been proposed to enclose a resiliently compressible solid foam material, e.g. foam rubber, within the tube. The current product is, however, relatively expensive since its production involves first forming the foam rubber insert 4 (Figure 2) and then wrapping it in a resilient outer 6, which is in the form of a strip or tape to form the tube.

This disadvantage is overcome by the present invention which provides a weather seal comprising a flexible tubular skin and resiliently compressible solid foam insert which are co-extruded.

Preferably, the foam insert is hollow. Control of the force required to compress the seal may then be achieved, at least in part, by controlling the size of the crosssection of the hole relative to the overall crosssection of the insert. Also, providing a hole through the insert enables the foam-forming material employed to form the insert to foam within the flexible tubular skin during manufacture. If the hole is not present, it is difficult for the gases generated during foaming to escape and the foam tends to be too hard or too dense for many applications.

The invention will now be described in greater detail with reference to a preferred embodiment and with the aid of the accompanying drawings in which:

- I - Figures 1A and 1B are cross-sections through one prior art form of weather seal in unstressed and compressed conditions;

Figure 2 is a cross-section through an improved form of prior art weather seal; Figure 3 is a cross-section through an embodiment of a weather seal according to the present invention; Figure 4; is a cross-section through the die of an extruder suitable for use in the production of the product illustrated in Figure 3;

Referring to Figure 3, in a preferred embodiment the weather seal comprises an extruded flexible hollow tube 12 having a resiliently compressible foamed coextruded insert 14 provided with a generally central hole 16. In the embodiment shown, the tube is formed integrally with a neck 18 and V-shaped flange 20. The flange is for fitting into a corresponding slot which is provided on some windows and doors or associated frames, thereby enabling the seal to be mounted on the window, door or frame, respectively.

The tube 12 and associated neck 18 and flange 20 are preferably extruded from a thermoplastic elastomer composition, e.g. SBS, EP, EPR, SEBS or mixture of two or more thereof. The insert 14 preferably comprises foamed elastomer and is preferably bonded to the inner wall of the tube. The bonding may be achieved simply by the normal heat applied during the coextrusion process. The elastomer of the foam and the elastomer of the tube may be the same or different. The foam is preferably a closed-cell foam, however, to prevent ingress of moisture.

The force required to compress the seal will be a function primarily of the nature of the material employed as the foamed elastomer, and the degree of foaming, and also of the size of the hole. If the hole 16 is too large, the function of the insert in prolonging the resilience of the seal in service may be adversely effected. If it is too small, the force required to compress the seal may be greater than desired and the product will be difficult to produce. Preferably the cross-sectional area of the hole is about 1/25 to 1/3 the cross-sectional area of the insert.

Referring now to Figure 4, the weather seal may be formed by co-extrusion using an extruder with two concentric die orifices 102, 104. The material forming the tubular skin is extruded through the outer orifice 102 and the foarn-forming composition which expands to form a resiliently compressible elastomeric foam core within the tubular skin is extruded through the inner orifice 104. Located centrally within the inner orifice is a tube 106 through which a compressed gas is injected, which is conveniently air, into the foam-forming composition to form an axially extending hole within the core. The size of the hole may be adjusted by adjustment of the pressure and rate of delivery of the gas. The compressed gas stream also acts to sweep the gas generated by the foaming of the foam-fonTling composition, thus encouraging expansion of the foam and enabling a soft resilient foam to be produced. The greater the flow rate of the air, the more efficient the removal of the gas generated by the foaming and the greater the degree of expansion of the foam and the lower its ultimate density. Thus, controlling the flow rate of the air provides a convenient means of controlling the compressibility of the product; i.e. the force required to compress it.

Claims

1. A weather seal comprising a flexible tubular skin and resiliently compressible foam insert which are co-extruded.

2. A weather seal as claimed in Claim I in which the foam insert is hollow.

3. A weather seal as claimed in Claim 2 in which the foam insert is provided with a generally central hole the cross-sectional area of which is about 1/25 to 1/3 the cross-sectional area of the insert.

4. A weather seal as claimed in any one of Claims 1 to 4 in which the foam is closed cell.

5. A method of forming a weather seal comprising co-extruding a flexible tubular skin and a foam-forming composition which expands to form a resiliently compressible foam core within the skin.

6. A method as claimed in claim 5 in which a compressed gas is injected into the foam forming composition to form an axially extending hole within the core.