GB2238591A

GB2238591A - Thatching spar

Info

Publication number: GB2238591A
Application number: GB8926416A
Authority: GB
Inventors: Jonathan Francis Fletcher
Original assignee: Individual
Current assignee: Individual
Priority date: 1989-11-22
Filing date: 1989-11-22
Publication date: 1991-06-05
Anticipated expiration: 2009-11-22
Also published as: GB2238591B; GB8926416D0

Abstract

A moulded plastics spar of U or V form (or capable of being flexed to that form) has limbs (1) and (2) each of T-shape in transverse cross-section, the confronting webs (5) forming the stems of the T-sections having a profiled edge to assist in gripping reeds of the thatch. The profiled edge has a series of barb formations (8) defined by an abutment shoulder (9) connected by a rounded corner (10) with a long back face (11). The barb formations help to resist removal of the staple from the reeds, yet avoid cutting of the reeds. <IMAGE>

Description

THATCHING SPAR This invention relates to a thatching spar.

Thatching spars are used to secure, either permanently or temporarily, a coatwork (layer) of new reeds to an underlying base coatwork. The base coatwork may be old or new.

Traditional spars are cut from hazel twigs which are split lengthwise to provide four splittings, the ends of the splittings are sharpened by the provision of three flats, and the splittings are bent into a U-shape for use. It has become more difficult to obtain adequate supplies of hazel twigs at a satisfactory price and there is a need for a cost-effective thatching spar.

It is known to use a long metal pin with a hooked outer end to secure particularly thick layers of reed in place to a thatch supporting roof structure, but such pins are not suitable as a general purpose spar.

According to the invention a thatching spar adapted to secure a bundle of reeds to an underlying layer of reeds of a thatched roof comprises first and second elongate limbs integrally connected by a bridging portion such that the spar is of substantially U-shape, or such that the limbs can be brought into alignment by flexing of the bridging portion to define a substantial U-shape, each of the limbs in transverse cross-section comprising a plurality of webs, at least one of the webs of at least one of the limbs being provided with a reed gripping means, which is so arranged as to resist any attempt to withdraw the spar from a layer of reeds into which the limbs have been inserted.

The spar is preferably formed by moulding, preferably from moulded plastics which may or may not be a filled plastics.

In the free, as-moulded state, the spar is preferably of substantially V-shape, the limbs extending at an acute angle to one another.

Each limb preferably comprises at least three webs which radiate from a longitudinal axis of the limb.

Preferably each limb comprises three webs only, and most preferably the webs are arranged in a T-configuration.

The web forming the stem of the T is preferably oriented substantially in that plane which includes the axes of both limbs.

The reed gripping means provided on said one web preferably comprises a profiled free edge of that web. The profiled edge may be of substantially barb-shape, preferably with rounded corners such that the reeds are not severed by the barbs in the event that it is required to withdraw the spar.

In a preferred embodiment in which the limbs are each of T-shape in transverse cross-section, the stem webs lying substantially in that plane which includes the axes of the limbs, the free edges of the stem webs are provided for part of their lengths with rounded barbs, and the free edges of the remaining webs are of undulatory shape.

A moulded plastics thatching spar in accordance with the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a side elevation of the spar in its condition of use, Figure 2 is a view of the spar looking from the right in Figure 1, but omitting the longer limb, and Figure 3 shows schematically the moulding of a plurality of such spars.

As shown in Figure 1, the moulded plastics spar comprises a first, longer limb 1 and a second, shorter limb 2, integrally connected by a bridging portion 3.

For convenience of moulding, and to provide a resilient splayingapart action of the limbs to assist retention of the spar in use, the spar is preferably moulded in a V-configuration with the limbs extending at approximately 30 to each other, as indicated in Figure 3 which shows a preferred arrangement for a plurality of such spars in a mould cavity. In Figure 3 the sprue positions are indicated by numerals 4.

The limbs 1, 2 and desirably of unequal lengths to accommodate the roof slope, the first limb 1 being positioned upwards of the slope in use.

Each of the limbs 1, 2 is of substantially T-cross-section for most of the length of the limb comprising a respective stem web 5, and a pair of co-planar webs 6, 7, constituting the cross-piece of the T-section.

The stem webs 5 lie in the same plane, that plane which includes the longitudinal axes of the limbs 1, 2, and are directed towards each other. The free edges at a mid-length of each of the webs 5 are profiled to define a plurality of barb formations 8.

Each of the barb formations comprises an abutment shoulder 9 extending at a substantial angle to the axis of the respective limb, a rounded corner 10, and a long back face 11 extending at only a small angle to said axis. As shown rounded corner 10 provides the connection between shoulder 9 and base face 11 of a barb formation, and a further, internal rounded corner 12 connects the base face 11 with the abutment shoulder 9 of adjacent barbs.

This shape of barb provides a substantial gripping action on a reed bundle which is in use trapped between the limbs 1, 2 by engagement with the webs 5, yet it is possible to withdraw the spar, if desired, without the barbs causing significant damage to the reeds engaged by the barbs.

As shown in Figure 2, the webs 6, 7 (of both limbs) have their edges of undulatory profile to define alternating thicker 13 and thinner 14 sections which assist in gripping reed which engages with the free edges of webs 6, 7. Since the webs 6, 7 are not shaped as barbs the retention forces will be kept within reasonable limits to enable withdrawal of the spar if desired.

The webs 6, 7 terminate short of pointed free ends 15, 16 of the webs 5, to assist the initial insertion of the spar into the reeds, and the adjacent end portions 17 of webs 6, 7 are made of spear shape to facilitate insertion.

Where the limbs 1, 2 merge with the bridging portion 3, the webs 6, 7 are continuous with the respective ribs of the other limb and remain of the same width, to define a flat platform 18 which spreads, in use, the impact of a mallet used to drive the spar home into the thatch. Initial insertion can be under hand pressure on the platform 18.

The stem webs 5 are progressively reduced in length at 51 so as to provide a measured degree of resilient give to the mid-portion of the bridging portion 3, to enable the limbs 1, 2 to be angularly flexed about the axis 20.

The plastics material can be of any suitable type of weatherresistant plastics having an appropriate degree of resilience and strength. The strength may, if desired, be improved by filling of the plastics, for example with glass fibre.

Claims

1. A thatching spar adapted to secure a bundle of reeds to an underlying layer of reeds of a thatched roof comprising first and second elongate limbs integrally connected by a bridging portion such that the spar is of substantially U-shape, or such that the limbs can be brought into alignment by flexing of the bridging portion to define a substantial U-shape, each of the limbs in transverse cross-section comprising a plurality of webs, at least one of the webs of at least one of the limbs being provided with a reed gripping means, which is so arranged as to resist any attempt to withdraw the spar from a layer of reeds into which the limbs have been inserted.

2. A spar as claimed in claim 1 and formed by moulding from plastics.

3. A spar as claimed in claim 1 or claim 2 which in the free, as-moulded state is of substantially V-shape, the limbs extending at an acute angle to one another.

4. A spar as claimed in any of the preceding claims in which each limb comprises at least three webs which radiate from a longitudinal axis of the limb.

5. A spar as claimed in claim 4 in which each limb comprises three webs only, and the webs are arranged in a T-configuration.

6. A spar as claimed in claim 5 in which the web forming the stem of thP T is oriented substantially in that plane which includes the axes of both limbs.

7. A spar as claimed in claim 6 in which the reed gripping means provided on said one web comprises a profiled free edge of that web.

8. A spar as claimed in claim 7 in which the profiled edge is of substantially barb-shape, with rounded corners such that the reeds are not severed by the barbs in the event that it is required to withdraw the spar.

9. A thatching spar substantially as described with reference to the accompanying drawings.

10. A thatched roof in which a layer of reeds is secured to an underlying layer of reeds by a plurality of thatching spars as claimed in any of the preceding claims.