GB2598379A

GB2598379A - Connector for joining thermal insulation material

Info

Publication number: GB2598379A
Application number: GB2013589.3A
Authority: GB
Inventors: Wheeler Alan
Original assignee: Greenraft Ltd
Current assignee: Greenraft Ltd
Priority date: 2020-08-28
Filing date: 2020-08-28
Publication date: 2022-03-02
Also published as: GB202013589D0

Abstract

The connector, particularly for joining bodies of thermal insulation material in insulated concrete formwork structures, comprises a strip 1 with longitudinal L and transverse T dimensions and two opposite faces 2,3, which includes two wing portions 4,5 that extend along the strip in the longitudinal dimension on opposite sides of an intermediate region 6, wherein each of the wing portions has at least one locking projection 9,10. The connector preferably has at least one locking projection on each opposing face. Each locking projection is preferably associated with a respective channel 13 in which it is received when flexing. The locking projections on opposite side faces are preferably mutually offset in the transverse direction. The intermediate region of the connector preferably includes two ribs 7,8, one on each opposite face. Also claimed is a thermal insulation structure and a method of joining two bodies of thermal insulation material in a poured concrete structure.

Description

CONNECTOR FOR JOINING

THERMAL INSULATION MATERIAL

TECHNICAL FIELD OF THE INVENTION

This invention relates to a connector which is particularly adapted for joining bodies of thermal insulation material.

BACKGROUND

Insulating concrete formwork (ICF) is increasingly being used in building construction. A formwork with inner and outer skins is constructed from blocks of lightweight thermal insulation material. The two skins are joined by spaced cross-ties and form a continuous cavity into which concrete is pumped. When the concrete hardens the skins provide permanent insulating layers on opposite sides of the concrete core. In one particular system which is supplied by Polarwall Limited of Exeter, top and bottom faces of the insulating blocks are connected by H-rails which are in turn interconnected by plastic cross-ties which snap-engage with the H-rails. The bottom-most course of blocks may be seated on U-rails which are also also connected by similar cross-ties. When the position of the walls is laid out on site the U-rails can be -2 -accurately positioned and fastened to a pre-laid concrete foundation or floor raft.

Often the concrete floor slab is constructed on a layer of thermal insulation material which is first laid over a layer of compacted aggregate blinded with a thin layer of sand. In such cases it is desirable for one or both skins of the insulating formwork to have close thermal contact with the insulating floor layer to prevent lateral heat loss from the floor slab. One way of achieving this is to prefabricate the thermal material off-site according to an architect's specifications. The wall blocks may, for example, slot into pre-formed channels in the insulating floor layer. Another way is to use L-shaped blocks linking the formwork to the floor insulation. There can, however, be inaccuracies in the wall positions if the flooring layer is not laid perfectly. For example, slight unevenness in the aggregate layer can cause slight distortion and cumulative variations in the spacing between pre-formed insulating boards which result in significant errors in the wall positions.

An objective of the present invention is to provide a new and inventive way of securely joining blocks of insulation material which is quick and accurate and can (if so desired) be carried out using only on-site fabrication.

SUMMARY OF THE INVENTION

When viewed from one aspect the present invention proposes a -3 -connector: a strip (1) having a longitudinal dimension (L), a transverse dimension (T), and two opposite faces (2, 3), the strip including two wing portions (4, 5) which extend along the strip in the longitudinal dimension on opposite sides of an intermediate region (6), wherein each of said wing portions has at least one locking projection (9, 10).

In a preferred embodiment each of said wing portions has at least one locking projection (9, 10) on each of said two opposite faces.

In a preferred embodiment each locking projection has an outer face (11) which is inclined away from the respective wing portion in the direction of the intermediate region.

In a preferred embodiment each locking projection has an inner face (12), opposite said outer face, which is inclined away from the respective wing portion in the direction of the intermediate region.

In a preferred embodiment each locking projection is associated with a respective channel (13) which extends along the respective wing portion in the longitudinal dimension.

In a preferred embodiment each channel is dimensioned to receive the respective locking projection upon flexing thereof.

In a preferred embodiment the locking projections (9, 10) on the -4 -opposite side faces (2, 3) of each wing portion are mutually offset in said transverse dimension.

In a preferred embodiment the intermediate region (6) includes two ribs (7, 8) which extend in the longitudinal dimension, one on each of said opposite faces.

The invention also provides a thermal insulation structure: - two bodies (23, 26) of thermal insulation material; - the connector; wherein each of said wings is inserted into a slot in a respective body of thermal insulation material to hold the two bodies together.

In a preferred embodiment one of the bodies (23) is comprised in a layer of thermal insulation in a floor structure and the other body (26) is a closer defining one edge of a floor slab (24) supported on said layer of thermal insulation.

In a preferred embodiment the two bodies are comprised in an insulating concrete formwork structure.

The invention also provides a method of joining two bodies of thermal insulation material in a poured concrete structure: - cutting a slot in one face of each body; - inserting the wing portions of the connector strip into the two slots to hold the two bodies together. -5 -

BRIEF DESCRIPTION OF THE DRAWINGS

The following description and the accompanying drawings referred to therein are included by way of non-limiting example in order to illustrate how the invention may be put into practice. In the drawings: Figure 1 is a transverse cross-sectional view of a connector for joining blocks of thermal insulation material, including an enlarged detail; Figure 2 is a vertical section through a ground-bearing floor structure incorporating bodies of insulation material which are joined together using the connector.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring firstly to Fig. 1, the connector 1 is a flexible strip which is formed from thermoplastic material such as polyethylene or polyvinyl chloride by an extrusion process. By way of example, the strip may typically be between 50 mm and 100 mm wide. The connector strip has a longitudinal dimension L and a transverse dimension T, and is of uniform cross-section throughout its length without through-apertures. The strip has two opposite faces 2 and 3 and includes two wing portions 4 and 5 of substantially equal width which extend along the strip in the longitudinal -6 -dimension L on opposite sides of an intermediate region 6. The intermediate region 6 is delineated by two shallow ribs, 7 and 8, one on the opposite faces 2 and 3, which both extend along the mid-line of the strip.

Each of the wing portions 4 and 5 has two resiliently flexible locking projections, 9 and 10, which are formed on the two opposite faces 2 and 3. The locking projections again extend along the strip in the longitudinal dimension L. As shown in the enlarged inset detail, each locking projection has an outer face 11 and an opposite inner face 12. Both faces 11 and 12 are inclined away from the respective wing portion 4, 5 in the direction of the intermediate region 6 (e.g. at an angle of about 160 degrees, as indicated). The two faces 11 and 12 are substantially parallel although they may converge slightly away from the respective wing portion as shown. Each locking projection 9, 10 is associated with a respective channel 13 which is formed in the associated face 2, 3. The channels similarly extend along the flexible strip in the longitudinal dimension L. One edge 14 of each channel 13 adjoins the base of the respective locking projection 9, 10, while the opposite edge 15 underlies the tip of the respective locking projection. The width and depth of each channel is dimensioned to receive the locking projection so that, when sufficient pressure is applied, the locking projections may flex inwardly towards the wing portions and enter the respective channels.

It will be noted that the locking projections 9 and 10 on the opposite faces 2, 3 of each wing portion are mutually offset in the -7 -transverse dimension T. This ensures that the wing portions do not need to be very thick to accommodate the locking projections and their respective channels 13. Furthermore, resilient deformation of both locking projections produces pressure at different positions on opposite sides of each wing portion so that the wing portion has a tendency to become slightly S-shaped under such sustained pressure. (See below.) Since the extruded connectors are flexible in their longitudinal dimension they can easily be wound onto a drum after manufacture for ease of storage and transportation. A length of the strip can then be unwound on site as required, and cut to the appropriate length.

The connector is particularly adapted to hold together two bodies of lightweight thermal insulation material. For example two boards can be connected edge-to-edge in the same plane or joined together at ninety degrees to each other. One particular application of the connector will now be described with reference to Fig. 2 which shows a typical insulated slab as used to construct the ground-bearing floor of a building. Following site excavation a layer of compacted hardcore 21 is laid over the sub-soil 20 and then blinded with a thin layer of sand 22. Thermal insulation boards 23, e.g. of extruded polystyrene, are laid edge-to-edge to support a poured concrete slab 24 which contains a steel reinforcement 25 to an engineer's specification. The edge of the slab is defined by a line of closer blocks 26 of a depth equal to the required depth of the poured slab. The closers may be of similar -8 -thermal insulation material to the boards 23 and are laid out on site and fixed to the boards in the measured positions according to a design specification. Fixation of the closers 26 is achieved by means of the connectors 1, described above, which are unrolled and cut to the required length. Matching grooves of the required depth and length are cut into the closers and the insulation layer on site using a standard circular saw blade. One wing of the connector is inserted into the insulation layer 23, and the other wing is inserted into a matching groove cut in the closers 26.

As the wings are inserted the locking projections 9 and 10 are deflected inwards towards the channels 13 so that they exert sustained outward pressure on the sides of the cut grooves. The channels 13 also provide additional space on the inside of the locking projections so that the projections are better able to bite into the thermal insulation material and provide an effective lock against withdrawal. The aforementioned tendency to form an S shape due to the offset projections may also assist with retention within the grooves. The shallow ribs 7 and 8 provide a visual indication to ensure that the first wing is inserted to the correct depth. After insertion, the outward force exerted by the locking projections effectively pulls the boards and closers together. The connectors thus create a strong mechanical fixation between the closers and the boards and provide the joint with high value mechanical shear resistance.

In addition to the connectors a suitable adhesive may be used to bond the boards and closers together in situations where a very -9 -high strength joint is required. If adhesive is used then the resilient locking elements act to pull the boards together and maintain sufficient pressure to allow the adhesive to set and create a good bond between the abutting faces of the boards and closers.

The connectors allow a very long and continuous join to be formed. To a certain extent the connector may also act as a water barrier to resist future passage of moisture through the joint.

The row of closer blocks 26 may be incorporated into the permanent formwork of an ICF wall using existing connection methods to join the closers to the insulation blocks such as the Polarwall H-rail system described above. The connectors can also be used at other positions in the ICE structure where the use of existing connections may not be possible, for example where a closer is to be fixed between the ICE skins around a window or door opening.

Various modifications to the connector described above are possible. In some uses apertures could be punched through the extruded connector strip at intervals, e.g. to reduce weight. It should also be noted that the wing portions 4 and 5 could be of unequal width if desired. It would also be possible for the junction region 6 to be delineated in other ways, e.g. by shallow marker grooves running along the mid-line of the strip. In some cases it may be sufficient if only one of the opposite faces 2 and 3 has a locking projection on each wing portion. Furthermore, in other -10 -applications the opposite faces 2 and 3 of each wing portion could each have more than one locking projection for extra strength.

Whilst the above description places emphasis on the areas which are believed to be new and addresses specific problems which have been identified, it is intended that the features disclosed herein may be used in any combination which is capable of providing a new and useful advance in the art.

Claims

CLAIMS1. A connector: a strip (1) having a longitudinal dimension (L), a transverse dimension (T), and two opposite faces (2, 3), the strip including two wing portions (4, 5) which extend along the strip in the longitudinal dimension on opposite sides of an intermediate region (6), wherein each of said wing portions has at least one locking projection (9, 10).
2. A connector according to claim 1 wherein each of said wing portions has at least one locking projection (9, 10) on each of said two opposite faces.
3. A connector according to claim 1 or 2 wherein each locking projection extends along the strip in the longitudinal dimension.
4. A connector according to any of claims 1 to 3 wherein each locking projection has an outer face (11) which is inclined away from the respective wing portion in the direction of the intermediate region.
5. A connector according to claim 4 wherein each locking projection has an inner face (12), opposite said outer face, which is inclined away from the respective wing portion in the direction of the intermediate region.
-12 - 6. A connector according to any preceding claim wherein each locking projection is associated with a respective channel (13) which extends along the respective wing portion in the longitudinal dimension.
7. A connector according to claim 6 wherein each channel is dimensioned to receive the respective locking projection upon flexing thereof.
8. A connector according to any preceding claim wherein the locking projections (9, 10) on the opposite side faces (2, 3) of each wing portion are mutually offset in said transverse dimension.
9. A connector according to any preceding claim wherein the intermediate region (6) includes two ribs (7, 8) which extend in the longitudinal dimension, one on each of said opposite faces.
10. A connector according to any preceding claim wherein the flexible strip is of uniform transverse cross throughout the longitudinal dimension.
11. A thermal insulation structure: - two bodies (23, 26) of thermal insulation material; - a connector according any of claims 1 to 10; wherein each of said wings is inserted into a slot in a respective body of thermal insulation material to hold the two bodies -13 -together.
12. A thermal insulation structure according to claim 11 wherein one of the bodies (23) is comprised in a layer of thermal insulation in a floor structure and the other body (26) is a closer defining one edge of a floor slab (24) supported on said layer of thermal insulation.
13. A thermal insulation structure according to claim 11 or 12 wherein the two bodies are comprised in an insulating concrete formwork structure.
14. A method of joining two bodies of thermal insulation material in a poured concrete structure: - cutting a slot in one face of each body; - inserting the wing portions of a connector strip according to any of claims 1 to x into the two slots to hold the two bodies together.
15. A method according to claim 14 wherein one of the bodies (23) is comprised in a layer of thermal insulation in a floor structure and the other body (26) is a closer defining one edge of a floor slab (24) supported on said layer of thermal insulation.
16. A method according to claim 14 or 15 wherein the two bodies are comprised in an insulating concrete formwork structure.