Improvements to fibre cement V-ridges

Abstract

 A fibre cement V-ridge (10) comprises substantially a roof portion (11) of V-shape and a recessed lap portion (12) at one end of the roof portion (11). At least one intermediate traverse reinforcement (15) is integrally provided on the under-side of two outreaching arms or planes of the roof portion (11). A lengthwise reinforcement (17) is integrally provided along the under-side of at least half of a bending line of the V-ridge (10). On the upper-side of the lap portion (12), at least one traverse drainage slot (14) is integrally provided. The V-ridge (10) is injection moulded and a preferred injection point (16) is disposed at the under-side of the intermediate traverse reinforcement (15) or the lengthwise reinforcement (17).

Description

TECHNICAL FIELD

[0001] This invention relates generally to double-lap slating, and particularly to improvements made to fibre cement V-ridges.

BACKGROUND OF THE INVENTION

[0002] Because of its various properties, fibre cement slates have been used instead of concrete tiles and the like. Their smooth surface and dressed edges closely resemble natural slate. With their light weight, strength and durability, fibre cement slates, including V-ridges, are economical and authentic.

[0003] Traditionally, fibre cement V-ridges are manually made, but they are also injection moulded recently. Prior art V-ridges are of a single thickness throughout. One end of the prior art V-ridge is a lap portion which is recessed as seen in Figure 1a The other end of the ridge is a large roof portion of the same thickness. In double-lap slating as shown in Figure 1b, the lap portion of one ridge and the roof portion of an adjacent ridge are overlaid. This means that the portions in contact are thicker than the thickness of the lengthwise roof portion When these ridges are eventually placed over purlins, the purlins support the weight of the ridges at these contacting and overlaid portions, whereas the rest of the lengthwise roof portions are suspended away from the purlins, and hence not supported. These are considered as weak spots during fixing or installation.

[0004] The apex of the V-shape results in a bending line for the V-ridge. This is a structural weakness of V-ridges. The bending line is prone to cracking during subsequent handling, fixing or installation.

SUMMARY OF THE INVENTION

[0005] The present invention has therefore as an object to improve fibre cement V-ridges so that they are structurally stronger and more stable.

[0006] This object is achieved in that at least one intermediate traverse reinforcement is integrally provided on the under-side of a V-ridge when in use, the thickness of the traverse reinforcement being substantially the same as the combined thickness of the contacting and overlaid portions between two adjacent ridges. Additionally, a lengthwise reinforcement is integrally provided along the under-side of at least half of a bending line of the V-ridge.

[0007] Another object of the invention is to provide traverse drainage slots on a lap portion, in order to lead out water, in case water happens to seep through in between the contacting and overlaid portions.

[0008] Yet, another object of the invention is to identify an injection point for making the fibre cement V-ridges according to the invention.

BRIEF DESCRIPTION

[0009] A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which:

Figure 1a shows in perspective an under-side view of a prior art

Figure 1b shows diagrammatically a cross-section side view of two contacting and overlaid prior art.

Figure 2 shows a perspective view of one specific embodiment of the invention.

Figure 3 shows an end view of the invention as shown in Figure 2.

Figure 4 shows a side view of the invention as shown in Figure 2.

Figure 5 shows in perspective an under-side view of the invention as shown in Figure 2.

Figure 6a shows diagrammatically a cross-section side view of two contacting and overlaid V-ridges made according to this invention.

Figure 6b shows an exploded cross-section view of two contacting and overlaid V-ridges shown in Figure 6a, illustrating two drainage slots.

DETAILED DESCRIPTION

[0010] Referring to one specific embodiment of the invention as shown in Figures 2, 3 and 4, a V-ridge (10) consists of substantially a large roof portion (11) of V-shape, and a recessed lap portion (12) at one end of the roof portion (11). In two dimensions viewing, a V-shape is made out from two outreaching arms, but in three dimensions viewing of the V-ridge (10), the arm takes the form of a plane. Throughout the description, "traverse" and "lengthwise" have been used. By "traverse", it is meant "in the direction of the outreaching arms or planes of the V-ridge". By "lengthwise", it is meant "an axis perpendicular to the V-shape".

[0011] When installed or in use, the V-ridge (10) is placed with its apex (13) at a higher position. A bending line is formed along the length of the V-ridge (10) at the position of the apex (13). It is important to note that the inclined angle between two outreaching arms or planes of the V-ridge can be varied depending on building applications.

[0012] Throughout the following description, the word "upper-side" or "under-side" connotes element of the V-ridge when it is installed or in use. Two traverse drainage slots (14) are integrally provided on the upper-side of the lap portion (12). When in use, the V-ridges (10) are overlaid, one over the other. The drainage slots (14) provide a means for water between the contacting and overlaid portions of the V-ridges (10) to run off. Otherwise, water may seep through crevices between the V-ridges (10).

[0013] As shown in Figure 5, the invention has been turned over to show an intermediate traverse reinforcement (15) integrally provided on the under-side of the V-ridge (10). The thickness of the intermediate traverse reinforcement (15) is substantially the same as the combined thickness of the lap portion (12) and the roof portion (11). It is important to note that the width of the intermediate traverse reinforcement (15) is enlarged somewhat.

[0014] A lengthwise reinforcement (17) is integrally provided along the under-side of at least half of the bending line of the V-ridge (10). This adds to the structural strength of the V-ridge (10) which will not be easily cracked along the bending line. The thickness of the lengthwise reinforcement (17) is substantially the same as the thickness of the intermediate traverse reinforcement (15).

[0015] It is important to note that a preferred injection point (16) is disposed at the under-side of the intermediate traverse reinforcement (15) or lengthwise reinforcement (17). The injection point (16) corresponds to the largest thickness of the V-ridge (10). If the injection point (16) is located elsewhere, the moulding process will not be efficient.

[0016] When the V-ridges (10) are installed or in use, their relative positions are shown in Figures 6a and 6b. Evidently, the underlying purlins support the V-ridges (10) at the positions of the intermediate traverse reinforcement (15) as well as the contacting and overlaid portions of the lap portions (12) and the roof portions (11). These in-contact positions represent support points between the purlins and the V-ridges (10). The intermediate traverse reinforcement (15) shortens the unsupported length of the V-ridges, hence increases the structural strength of the V-ridges (10).

[0017] From the above description, it is clear that both the intermediate traverse reinforcements (15) and the lengthwise reinforcements (17) increase the structural strength of the V-ridges (10) according to this invention.

Claims

1. A fibre cement V-ridge (10) comprising substantially a large roof portion (11) of V-shape and a recessed lap portion (12) at one end of the roof portion (11), is characterised in which
at least one intermediate traverse reinforcement (15) is integrally provided on the under-side of two outreaching arms or planes of its roof portion (11).

2. A fibre cement V-ridge (10) as in Claim 1 in which a lengthwise reinforcement (17) is integrally provided along the under-side of at least half of a bending line of the V-ridge (10).

3. A fibre cement V-ridge (10) as in Claim 1 in which the thickness of the intermediate traverse reinforcement (15) is substantially the same as the combined thickness of the lap portion (12) and the roof portion (11).

4. A fibre cement V-ridge (10) as in Claim 3 in which the width of the intermediate traverse reinforcement (15) is enlarged.

5. A fibre cement V-ridge (10) as in Claim 1 in which at least one traverse drainage slot (14) is integrally provided on the upper-side of the lap portion (12) when the V-ridge (10) is in use.

6. A fibre cement V-ridge (10) as in Claim 1 in which the V-ridge (10) is injection moulded and a preferred injection point (16) is disposed at the under-side of the intermediate traverse reinforcement (15).

7. A fibre cement V-ridge (10) as in Claim 2 in which the thickness of the lengthwise reinforcement (17) is substantially the same as the thickness of intermediate traverse reinforcement (15).

8. A fibre cement V-ridge (10) as in Claim 2 in which the V-ridge (10) is injection moulded and a preferred injection point (16) is disposed at the under-side of the lengthwise reinforcement (17).

Drawing