GB2511492A

GB2511492A - Template for fabricating rafters

Info

Publication number: GB2511492A
Application number: GB1303542.3A
Authority: GB
Inventors: David Atkinson
Original assignee: Individual
Current assignee: Individual
Priority date: 2013-02-28
Filing date: 2013-02-28
Publication date: 2014-09-10
Anticipated expiration: 2033-02-28
Also published as: GB201303542D0; GB2511492B

Abstract

The template comprises a substantially L-shaped element 9 adapted to fit over a part of a building. A first arm 11 is pivotably mounted at one end at a first point 12 on the L-shaped element. The first arm is also provided with means for pivotably mounting the first arm at a second point 15 spaced from the first point. A second arm 13 is pivotably mounted at one end at a third point 14 on the L-shaped element , spaced from the first point. The second arm is also provided with means for pivotably mounting the second arm at a fourth point spaced from the third point. The template may also include a second L shaped part and further pivotably mounted arms. The arms may be connected to an extendable elongate bar 7. The first arm may include a mounting point which is adjustable by having a number of through holes or releasably movable along an elongate slot. The template may include a further component comprising two arms which are pivotally interconnected at one end. The template allows formation of a rafter while taking into account a birds mouth cut.

Description

TEMPLATE FOR FABRICATING RAFTERS

This invention relates to a template for fabricating rafters.

Rafters take a number of general forms, but a basic rafter is cut at its upper end so that, when installed, it provides the required pitch to a roof, while making a flush attachment to a roof beam orto an opposing rafter. The upper cut is known as a plumb cut because in practice it is substantially vertical. The lower end of the rafter may be cut in a number of ways, such as vertically, horizontally, or a combination of an outer vertical cut and a lower horizontal cut. Between the upper and lower ends the rafter is supported on a wall plate by way of a L-shaped cut, or bird's mouth, tormed on an underside of the rafter. Occasionally, the lower end may have a different configuration and may simply have a substantially horizontal face that bears directly on the wall plate. It is a complex and time-consuming task to mark up a length of timber to be cut to form a rafter, in particular marking up the bird's mouth. This is in part because the rafter, when in position, is at a different position relative to the building than when it is applied to the building for marking-up (that is, the bird's mouth affects the location of the timber relative to its longitudinal axis because it alters the point at which the timber bears against the wall plate). The bird's mouth is important, though, because it increases the ability of the rafter to bear loads.

For the roof to lie properly, all the rafters must be cut to the required length, with the correct angles, and have an accurately positioned bird's mouth cut. This requires a skilled craftsman and takes a considerable time.

It is therefore an object of the present invention to provide a template for fabricating rafters which overcomes, or at least ameliorates, the above-mentioned problem.

According to the present invention there is provided a template for fabricating rafters, the template comprising a substantially L-shaped element adapted to fit over a part of a building, a first arm pivotably mounted at one end at a first point on the L-shaped element and provided with means for pivotably mounting the first arm at a second point spaced from the first point, and a second arm pivotably mounted at one end at a third point on the [-shaped element, spaced from the first point, and provided with means for pivotably mounting the second arm at a fourth point spaced from the third point.

The template may include a further substantially L-shaped element adapted to fit over a part of a building, a further first arm pivotably mounted at one end at a first point on the further L-shaped element and provided with means for pivotably mounting the further first arm at a second point spaced from the first point, and a further second arm pivotably mounted at one end at a third point on the further [-shaped element, spaced from the first point, and provided with means for pivotably mounting the further second arm at a fourth point spaced from the third point.

The template may include an elongate member, such as a disposable batten or an elongate, optionally extendable, bar.

The first arm may be provided with first mounting means for pivotably mounting the first arm, for example to the elongate member, at a point along the first arm spaced from the mounting point. The mounting means may comprise a plurality of through holes spaced along the length of the arm, for example through which a fastener, such as a threaded fastener, can be inserted. Alternatively, the mounting means may comprise mounting means which may be secured at any chosen point along the length of the first arm or the mounting means may be provided in the region of a free end of the arm, and the arm may be provided with means for adjusting the length thereof or the mounting means may be releasably movable along an elongate slot provided along the length of the arm. In this latter case, a threaded member may be mounted on a stud forming part of the mounting means and passing through the elongate slot, the threaded member being rotatable to releasably engage the arm, for example by way of a suitable washer.

The second arm may be provided with second mounting means for pivotably mounting the second arm, for example to the elongate member, at a point spaced from the point at which the first arm can be mounted and at a point along the second arm spaced from the mounting point thereon. The second mounting means may comprise a bracket to which the region of the free end of the second arm is pivotably mounted. The bracket may comprise a first and second substantially planar portions provided substantially at right angles to each other.

One or both of the planar portions may be provided with through holes for the passage of a fastener, such as a threaded fastener. Alternatively, the second mounting means may comprise a plurality of through holes spaced along the length of the second arm, for example through which a fastener, such as a threaded fastener, can be inserted, or the mounting means may comprise mounting means which may be secured at any chosen point along the length of the second arm, or the mounting means may be provided in the region of the free end of the second arm, and the arm may be provided with means for adjusting the length thereof or the mounting means may be releasably movable along an elongate slot provided along the length of the arm. In this latter case, a threaded member may be mounted on a stud forming part of the mounting means and passing through the elongate slot, the threaded member being rotatable to releasably engage the arm, for example by way of a suitable washer. As a further alternative, the second arm may be in the form of two arm portions which are pivotable about interconnected ends thereof, the pivot being releasably lockable so as to secure the arm portions relative to each other.

One or both of the arms of the or each L may be provided with one or more through holes by which the [-shaped element can be releasably secured to a part of a building. Alternative releasable securing means include a releasable clamp, and an angled element mounted to one side of the L-shaped element and provided with one or more through holes for releasably securing the first component to part of a building.

The first arm may be pivotably mounted at one end thereof at a point in the region of the free end of the longer arm of the L and the second arm may be pivotably mounted at one end thereof ata point in the region of the other end of the longer arm of the L or, alternatively, at a mounting point on the shorter arm of the L. The first component may be mounted at a lower end (in use) of the elongate member.

The template may include a further component comprising a first arm and a second arm, the first and second arms being pivotably interconnected at one end of each arm. The two arms may be releasably locked in a chosen configuration if desired. Each arm may be provided with a plurality of through holes spaced along the length thereof, for example to facilitate securing of the arms to the elongate member.

For a better understanding of the present invention and to show more clearly how it may be carried into effect reference will now be made, by way of example, to the accompanying drawings in which: Figure 1 is a diagrammatic illustration of one embodiment of a template for fabricating rafters according to the present invention, the template incorporating a number of individual components forming aspects of the invention; Figure 2 shows part of a first component of the template in more detail; Figure 3 shows an alternative configuration of part of the first component in more detail; Figure 4 shows a further alternative configuration for part of the first component in more detail; Figure 5 is a diagrammatic illustration of the use of a second component of the template for forming a lay board or valley board of a roof; Figure 6 illustrates use of the template in the fabrication of jack rafters; and Figure 7 Is a diagrammatic illustration of use of the first components of the template shown in Figure 1.

Figure 1 shows one embodiment of a template for fabricating rafters according to the present invention. The template includes a first component for bearing against a wall plate 1 and for indicating a bird's mouth to be cut in a rafter, a second (optional) component for indicating a plumb cut at an upper end of the rafter where the rafter bears against a ridge beam 3, and a third (optional) component for indicating a bird's mouth to be cut at where the rafter bears against an intermediate purlin 5. The ridge beam may be positioned between two sets of rafters as shown or may be secured to a wall so as to support a single set of rafters such as in the case of a lean-to roof. The third component and the first component may be identical, for example taking the form of the third component as illustrated in Figure 1.

As will be explained hereinafter, the template can be used for common rafters, hip rafters, inverted hip rafters, jack rafters and other roof parts such as lay boards, valley boards and ridge beams.

The individual components are employed in conjunction with an elongate member 7 such as a disposable batten, for example a 50mm by 25 mm batten such as is commonly found on a building site. Alternatively, an elongate, optionally extendible, bar may be used in place of the batten as the elongate member.

The first component is mounted at a lower end of the elongate member 7 and comprises a substantially L-shaped element 9 in which in use the longer arm of the L is substantially horizontal and the shorter arm of the L extends substantially vertically downwards so as to engage the wall plate 1. One or both of the arms of the [ are provided with one or more through holes by which the [-shaped element can be releasably secured to the wall plate 1. Alternative releasable securing means can be employed, such as a releasable clamp or an angled element 10 mounted to one side of the L-shaped element and provided with one or more through holes for releasably securing the first component to the wall plate 1, as shown in Figure 2. A first arm 11 is pivotably mounted at one end thereof eta point 12 in the region of the free end of the longer arm of the Land a second arm 13 is pivotably mounted at one end thereof at a point 14 in the region of the other end of the longer arm of the L (although the second arm 13 may alternatively be pivotably mounted at a mounting point on the shorter arm of the L).

The first arm may have a width of about 20 mm and a length of about 400 mm, while the second arm may have a width of about 20 mm and a length of about 400 mm. A shorter length second arm, of about 300 mm, may be provided for alternative use, such as in the case of inverted hip rafters. The longer arm of the L may be about 100mm and the shorter arm may be about 60 mm, the width of each arm being about 20 mm. In each case alternative dimensions may be used.

The first arm 11 is provided with first mounting means 15 for pivotably mounting the first arm to the elongate member 7 at a point along the first arm spaced from the mounting point 12. The mounting means 15 may comprise a plurality of through holes 15 spaced along the length of the arm as shown in Figure 1 through which a fastener, such as a threaded fastener can be inserted, but alternatively the mounting means may comprise mounting means which may be secured at any chosen point along the length of the first arm 11 or the mounting means may be provided in the region of a free end of the arm 11 and the arm may be provided with means for adjusting the length thereof or the mounting means may be releasably movable along an elongate slot provided along the length of the arm as shown in Figure 3 where a threaded member may be mounted on a stud forming pad of the mounting means and passing through the elongate slot, the threaded member being rotatable to releasably engage the arm by way of a suitable washer.

The second arm 13 is provided with second mounting means 17 for pivotably mounting the second arm to the elongate member 7 at a point along the elongate member spaced from the point at which the first arm 11 is mounted and at a point along the second arm spaced from the mounting point 14. The second mounting means 17 may comprise a bracket to which the region of the free end of the second arm is pivotably mounted, the bracket having a length of about 100 mm, for example. The bracket may comprise a first substantially planar portion adapted to be positioned against a side of the batten and a second substantially planar portion adapted to be positioned against a surface of the batten remote from the L-shaped element, one or both of the planar portions being provided with through holes for the passage of a fastener, such as a threaded fastener.

Alternatively, the second mounting means may comprise a plurality of through holes spaced along the length of the second arm for receiving a fastener, such as a threaded fastener or any of the further alternatives described in relation to the first arm 11. As a further alternative, as shown in Figure 4, the second arm may be in the form of two arm portions which are pivotable about interconnected ends thereof, the pivot being releasably lockable so as to secure the arm portions relative to each other when the template has been adjusted to the dimensions of a rafter.

When both the first and second arms 11, 13 are secured to the elongate member the L-shaped element 9 is positioned at a predetermined distance from the elongate member and at a predetermined angle relative to the elongate member.

These are determined by securing the L-shaped element to the wall plate and resting the upper end of the elongate member against the ridge beam. Once the first and second arms have been correctly positioned and secured, the arms, the L-shaped element and part of the elongate member form a quadrilateral which is substantially rigid until the fasteners have been removed. The elongate member may be secured to the ridge beam by the second component if desired, as will be explained hereinafter. The underside of the elongate member 7 corresponds to the position of the top of the rafter to be cut and secured in place, so the relative positioning of the first and second arms 11, 13 and their respective mounting means is first adjusted such that the underside of the elongate member is located a desired distance from the wall plate 1 (allowing for the bird's mouth to be formed in the rafter. The location and orientation of the upper end of the rafter can then be marked on the elongate member or the position of the second component can be used to determine the location and orientation of the upper end of the rafter.

The L-shaped element 9 is then released from the wall plate 1 and placed against an edge of a timber intended to form the rafter. The bird's mouth can be marked directly onto the timber and the upper end ot the ratter can either be extrapolated from the marking on the upper end of the elongate member or the location and orientation of the second component. The rafter can then be cut to size and shape and secured directly to the wall plate 1 and ridge beam 3.

As shown in Figure 1, the second component comprises a first arm 21 and a second arm 23, the first and second arms being pivotably interconnected at one end of each arm. Each arm may have a width of about 6 mm and a length of about 300 mm, but other dimensions are possible. The two arms may be releasably locked in a chosen configuration if desired. Each arm is provided with a plurality of through holes spaced along the length thereof to facilitate securing of the arms to the elongate member 7. When the elongate member is in position, bearing against the ridge beam 3, the first arm 21 of the second component is secured to the elongate member 7 immediately adjacent to the ridge beam and allowed to be oriented substantially vertically and the second arm 23 is then secured to the elongate member to maintain the orientation of the first arm.

Where the second component is used in this manner, the location and orientation of the upper end otthe rafter can be directly transcribed to the timber forming the rafter.

Where the root includes a longitudinally extending purlin 5 then a third component is employed in the manner of the first component (and, as has previously been noted, may be in the same form as the first component) in order to determine the location and orientation of the bird's mouth required for the rafter to bear on the purlin. When the third component has been correctly located and oriented the bird's mouth can be directly transcribed to the timber forming the rafter.

When the timber has been fully marked-up, it can be cut to shape and size and mounted on the roof.

In the case of a hip rafter and an inverted hip (valley) rafter, where the end of the rafter is required to fit within a 90 degree angle, the location and orientation of the cut to be made must be transcribed in effect to the centre of the timber, from which point two 45 degree lines are marked to achieve the 90 degree corner.

Also, the lower end ofan inverted hip should have a spacer at 45 degrees across the adjoining wall plates (which are at 90 degrees to each other) to allow determination of the bird's mouth at the lower end of the rafter.

A lay board or a valley board can be determined with the aid of two of the second components. As illustrated in Figure 5, a first one of the second components is provided at a position on the elongate member corresponding to a lower end of the lay board or valley board and provides a template for the lay board or valley board in the direction of the wall plate of the main roof, while a second one of the second components is provided at a position on the elongate member corresponding to an upper end of the lay board or valley board and provides a template in the direction of the ridge beam of the intersecting subsidiary roof structure.

The first and second components of the template can also be used to fabricate jack rafters as shown in Figure 6. In this case the [-shaped element 9 of the first component is secured to the wall plate 1 with the upper end of the elongate member 7 resting against a hip rafter 31. The second component is then secured in placed adjacent to the hip rafter and provides a template for the plumb cut at the upper end of the jack rafter. The underside of the elongate member can be used to provide the angle relative to the hip which can be marked with a pencil or the like on the underside of the elongate member. As previously explained, the template can then be placed against an edge of a timber to form the jack rafter and the cuts transcribed from the template to the timber prior to cutting.

The template can be adapted for use with a ridge beam 33 to which the rafters are attached by way of a bird's mouth as shown in Figure 7 as compared with a ridge beam as shown in Figure 1 in which the rafters bear against sides of the ridge beam. As shown in Figure 7, two of the first components of the template are employed to establish the locations and orientations of two bird's mouths for transcription to a timber forming the rafter.

Claims

CLAIMS1. A template for fabricating rafters, the template comprising a substantially L-shaped element adapted to fit over a part of a building, a first arm pivotably mounted at one end at a first point on the L-shaped element and provided with means for pivotably mounting the first arm at a second point spaced from the first point, and a second arm pivotably mounted at one end at a third point on the L-shaped element, spaced from the first point, and provided with means for pivotably mounting the second arm at a fourth point spaced from the third point.
2. A template as claimed in claim 1 and including a further substantially L- 04 shaped element adapted to fit over a part of a building, a further first arm pivotably mounted at one end at a first point on the further L-shaped element 0 and provided with means for pivotably mounting the further first arm at a second point spaced from the first point, and a further second arm pivotably mounted at one end at a third point on the further L-shaped element, spaced from the first point, and provided with means for pivotably mounting the further second arm at a fourth point spaced from the third point.
3. Atemplateasclaimed inclaim 1 or2and includinganelongatemember.
4. A template as claimed in claim 3, wherein the elongate member comprises an elongate bar.
5. A template as claimed in claim 4 wherein the elongate bar is extendable.
6. A template as claimed in any preceding claim, wherein the first arm is provided with first mounting means for pivotably mounting the first arm at a point along the first arm spaced from the mounting point.
7. Atemplate as claimed in claim 6, wherein the mounting means comprises a plurality of through holes spaced along the length of the arm.
8. Atemplate as claimed in claim 6, wherein the mounting means comprises mounting means which may be secured at any chosen point along the length of 04 the first arm.LO0
9. A template as claimed in claim 6, wherein the mounting means is provided in the region of a free end of the arm, and the arm is provided with means for adjusting the length thereof.
10. A template as claimed in claim 6, wherein the mounting means is releasably movable along an elongate slot provided along the length of the arm.
11. A template as claimed in claim 10, wherein a threaded member is mounted on a stud forming part of the mounting means and passing through the elongate slot, the threaded member being rotatable to releasably engage the arm.
12. A template as claimed in any preceding claim, wherein the second arm is provided with second mounting means for pivotably mounting the second arm at a point spaced from the point at which the first arm can be mounted and at a point along the second arm spaced from the mounting point thereon.
13. A template as claimed in claim 12, wherein the second mounting means comprises a bracket to which the region of the free end of the second arm is pivotably mounted.
14. A template as claimed in claim 13, wherein the bracket comprises first and second substantially planar portions provided substantially at right angles to each other.LOO
15. A template as claimed in claim 14, wherein one or both of the planar portions is provided with through holes for the passage of a fastener.
16. A template as claimed in claim 12, wherein the second mounting means comprises a plurality of through holes spaced along the length of the second arm.
17. A template as claimed in claim 12, wherein the mounting means comprises mounting means which may be secured at any chosen point along the length of the second arm.
18. A template as claimed in claim 12, wherein the mounting means is provided in the region of the free end of the second arm, and the arm is provided with means for adjusting the length thereof.
19. A template as claimed in claim 12, wherein the mounting means is releasably movable along an elongate slot provided along the length of the arm.
20. A template as claimed in claim 19, wherein a threaded member is mounted on a stud forming part of the mounting means and passing through the elongate slot, the threaded member being rotatable to releasably engage the arm. (421. A template as claimed in claim 12, wherein the second arm is in the formLO0 of two arm portions which are pivotable about interconnected ends thereof, the pivot being releasably lockable so as to secure the arm portions relative to each other.22. A template as claimed in any preceding claim, wherein one or both of the arms of the or each L is provided with one or more through holes by which the L-shaped element can be releasably secured to a part of a building.23. A template as claimed in any one of claims 1 to 21, wherein one or both of the arms of the or each L is provided with releasable securing means in the form of a releasable clamp.24. A template as claimed in any one of claims 1 to 21, wherein one or both of the arms of the or each L is provided with releasable securing means in the form of an angled element mounted to one side of the L-shaped element and provided with one or more through holes for releasably securing the first component to part of a building.25. A template as claimed in any preceding claim, wherein the first arm is pivotably mounted at one end thereof at a point in the region of the free end of the longer arm of the L and the second arm is pivotably mounted at one end thereof at a point in the region of the other end of the longer arm of the L. 26. A template as claimed in any one of claims I to 24, wherein the first arm is pivotably mounted at one end thereof at a point in the region of the free end 0 of the longer arm of the L and the second arm is pivotably mounted at one end thereof at a mounting point on the shorter arm of the L. 27. A template as claimed in any preceding claim, wherein the first component is mounted in use at a lower end of the elongate member.28. A template as claimed in any preceding claim and including a further component comprising a first arm and a second arm, the first and second arms of the further component being pivotably interconnected at one end of each arm.29. A template as claimed in claim 28, wherein the two arms of the further component are adapted to be releasably locked in a chosen configuration.30. A template as claimed in claim 29, wherein each arm of the further component is provided with a plurality of through holes spaced along the length thereof.31. A template for fabricating rafters substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings. (4LO