GB2399356A

GB2399356A - Bolted conservatory rafters utilising cap to prevent bolt movement

Info

Publication number: GB2399356A
Application number: GB0305735A
Authority: GB
Inventors: Paul Rickman
Original assignee: PLANET ROOF SYSTEMS Ltd
Current assignee: PLANET ROOF SYSTEMS Ltd
Priority date: 2003-03-13
Filing date: 2003-03-13
Publication date: 2004-09-15
Anticipated expiration: 2023-03-13
Also published as: GB2399356B; GB0305735D0

Abstract

A rafter 20 is attached to a support beam 10, wherein the rafter 20 has a generally upwardly-facing channel 27 defined by side webs (28, fig 2) upstanding from a face 22 of the rafter. The rafter is positioned on the support beam 10 and a hole drilled through the channel 27 into the beam. The hole receives a bolt (36, fig 2) with a head 37 located between the side webs (28) which is prevented from turning thereby. A clip 38 fits over the head 37 of the bolt (36) and engages the side webs (28), whereafter a nut threaded on to the bolt projecting below the beam 10 may be tightened, without needing access to the head of the bolt. The clip 38 may be U-shaped and is preferably held on barb-shaped ribs extending along the side webs. The rafter 20 may be attached to the beam in two channels 27 on either side of a central web by the above fixing.

Description

RAFTER FIXING

This invention relates to methods of fixing a rafter to a support beam, for example in the production of a roof for a domestic conservatory. Further, this invention relates to a fixing arrangement for attaching a rafter to a support beam.

It is the common practice when constructing a conservatory to manufacture the roof from a plurality of extruded sections typically of aluminium or of high molecular weight polyvinyl chloride (nPVC). Typically, there will be an eaves beam extending around the upper periphery of the walls of the conservatory, and in the case of a pitch roof, a ridge beam disposed centrally of the conservatory above the level of the eaves beam. With a lean-to design, there will be a ridge beam similar to that of a pitch roof but secured to a wall of a building on which the conservatory depends. Rafters extend between the ridge beam and the eaves beam and each sheet of glazing material (be it of glass or of plastics) is supported along its side edges by the rafters, with the top and bottom edges of the sheet being supported by the ridge beam and eaves beam, respectively.

Each rafter must separately be secured to the eaves beam and this usually is done by placing the rafter in the required position and then drilling through a base wall of the rafter and a supporting wall of the eaves beam, "hereafter a nut and bolt are fitted to the aligned drilled holes, to complete the connection. Altematively, the rafter and eaves beam may be separately fitted at the appropriate positions and then assembled together to align the drilled holes, "hereafter a nut and bolt are fitted to the aligned holes, as before.

Conventionally, the bolt is pushed up from underneath and the nut is used to clamp down the rafter, with the nut being fumed from above the eaves beam.

Such an operation must normally be effected on a ladder and is less than wholly convenient.

In order to address the above problem, there have been proposals for a fixing arrangement where a bolt is provided on a rafter at an appropriate position and then the rafter together with its bolt is fitted to an eaves beam with a pre-drilled hole at the required position. Then, a nut may be run up the bolt from below, to complete the connection. This is significantly easier and faster to perform and also enhances operator safety.

In one such proposal (WO 02/097213) an extruded rafter section includes a downwardly-facing channel centrally of the extrusion, which channel includes a pair of flanges directed towards each other at the bottom (mouth) of the channel whereby the head of a bolt may be accommodated in the channel at an appropriate position by sliding the bolt lengthwise of the rafter from one end thereof. By making the head of the bolt a snug fit in the channel, the bolt also is held against rotation as a nut is tightened from below. However, this arrangement has the disadvantage that a open channel is formed for the length of the rafter and so a capping plate must be fitted over that open channel so as to enhance the visual appearance thereof. Further, the fixing of the rafter can be completed with only one bolt and there is nothing to restrain the bolt in the required position and so prevent the bolt from sliding along the rafter, until the connection is tightened down.

The present invention aims at providing an improved method and fixing arrangement for attaching a rafter to a support beam, in order to simplify yet further the process of securing a rafter to an eaves beam and to permit the fixing to be undertaken solely from below.

Accordingly, according to one aspect of the present invention there is provided a method of fixing a rafter to a support beam wherein the rafter has a generally-upward facing channel formed therealong which channel is defined by a pair of spaced side webs upstanding from a face of the rafter, comprising the steps of: positioning the rafter on the support beam in the required position; drilling a hole substantially perpendicularly through the channel and into the beam; inserting a bolt through the drilled hole so that the head of the bolt is located between the side webs of the channel and is prevented from fuming thereby; fitting a clip over the head of the bolt which clip engages the outside faces of the side webs to be retained thereby; and threading a nut on to the part of the bolt projecting below the beam, to tighten the rafter to the beam.

According to a second, but closely related, aspect of this invention, there is provided a method of fixing a rafter to a support beam wherein the rafter has a generally-upward facing channel formed therealong which channel is defined by a pair of spaced side webs upstanding from a face of the rafter, comprising the steps of: drilling a hole substantially perpendicularly through the channel of the rafter at the required position along the length of the rafter; inserting a bolt through the drilled hole so that the head of the bolt is located between the side webs of the channel and is prevented from fuming thereby; fitting a clip over the head of the bolt which clip engages the side webs to be retained thereby; drilling a hole through the eaves beam at the location where the rafter is to be fixed; positioning the rafter on the support beam with the bolt passing through the drilled hole in the eaves beam; and threading a nut on to the part of the bolt projecting below the beam, to tighten the rafter to the beam.

These two aspects of the invention differ in the order in which the steps of the method are performed. In the former, the rafter is fitted to the eaves beam and the assembly is drilled in situ, but in the latter the eaves beam and the rafter are appropriately marked and then fitted separately before being assembled together.

to According to yet another aspect of this invention, there is provided a fixing arrangement for attaching a rafter to a support beam in which arrangement: the rafter is provided with a generally-upward facing channel extending therealong and defined by a pair of spaced side webs upstanding from a face of the rafter, a bolt passes through aligned holes s in the channel and the support beam, the head of the bolt locating in the channel between the side webs thereof and being prevented from turning thereby; a clip is fitted over the head of the bolt which clip engages the outside faces of the side webs to be retained thereby; and a nut is threadingly engaged with the part of the bolt projecting below the beam, no to clamp the rafter to the beam.

It will be appreciated that with both methods and the fixing arrangement of this invention, a generally upwardly facing channel is provided along the rafter, which channel may be defined by a pair of opposed side webs which upstand from a base section of the channel, the webs being spaced by a distance appropriate for the head of a bolt to be accommodated therebetween.

Then, following the drilling of a hole through the base of the channel, a bolt is passed through that hole and held in position by the clip. The bolt cannot slide along the channel, the clip prevents the bolt from lifting out of the channel and the underside of the rafter has no unsightly slot which must subsequently be covered over.

Further, having regard to the shape of a typical extruded rafter which is intended to support glazing on both sides, it is possible to provide two channels 0 in the base section of the rafter, one to each side of the central vertical plane.

Two bolts may then be used to provide an enhanced connection, one bolt to each side of the rafter.

The clip preferably is generally U-shaped and has a base section from which extend opposed arms, the inside faces of the arms interengaging with the outside faces of the side webs to secure the clip in position over a bolt. The outside face of each side web may have a rib extending therealong, and each arm of the clip is held to the channel by engaging an inwardly directed abutment on each arm behind the respective rib. To facilitate interengagement of the clip with the channel, each said rib may be of barbed-shaped cross section. In this way, the abutment on each arm may more readily ride over the respective rib.

Conveniently, the clip is formed by a pressing operation on sheet metal such as spring steel. The abutment on each arm may then be defined by turning inwardly the free longitudinal edge of each arm, towards the opposed arm.

By way of example only, one specific embodiment of this invention will now be described in detail, reference being made to the accompanying drawings, in which: Figure 1 is an isometric cut-away view of the assembly of a rafter with an eaves beam in a domestic conservatory roof construction; and Figures 2A and 2B show two different rafters profiled for performing the method of this invention.

Referring initially to Figure 1, there is shown an eaves beam 10 intended for installation around the upper part of the walls of a domestic conservatory.

The eaves beam is an aluminium alloy extrusion, and is suitably profiled having regard to the function it must fulfil. Thus, the eaves beam 10 has a foot portion 11 to be secured to the top of the side walls of the conservatory, an internal face 12 which in use is covered by a trim plate 13 and a rafter fixing surface 14 opposed to the foot portion 11. The outwardly directed face 15 is adapted for the mounting of a gutter section 16 thereto.

The rafter fixing surface 14 is carried by a hollow section 17 so as to be above the main box section of the eaves beam 10, the rafter fixing surface including a channel 18 and a load bearing surface 19 on which a rafter 20 bears.

The rafter 20 also is an aluminium alloy extrusion and has a base section 22 from the centre of which upstands a column 23. The base section is profiled so as to be suitable to support glazing to each side of the central column 23, for example by using a glazing trim 25 (Figures 2A and 2B) which fits externally around the base section and is provided with sealing lips 26 on which the glazing panels are carried.

To each side of the column 23, there is formed a channel 27 on the base section 22, defined by a pair of spaced webs 28 upstanding from the base section. Each web has a barb 29 formed externally along its free edge, for a purpose to be described below.

The rafter is completed by a cap strip 31 having a central mounting 32 which is received in the column 23 as shown in Figures 2A and 2B. The cap strip includes side legs 33 each terminating in a glazing seal 34 such that when fully assembled, with glazing bearing on the sealing lips 26 of the glazing trim 25, the cap strip 31 may be pressed down so as to bear on that glazing and retain it in position.

The rafter 20 is secured to the eaves beam 10 by a pair of bolts 36 each having a conventional hexagonal head 37. The across-the-flats dimension of the head 37 substantially equal to the internal spacing of the webs 28 defining the channel 27. A hole is drilled through the base section 22 of a rafter at an appropriate position, centrally of the channel, and then a bolt is passed through that hole so that the head fits between the side webs. The bolt is then held in position by a spring metal clip 38 of Cshaped cross-section, the clip being formed of pressed steel and having the free edges 39 of the arms 40 fumed inwardly to face each other, as best seen in Figures 2A and 2B. Once a bolt has been passed through a drilled hole in the base section, the clip may be fitted over the bolt head with the inturned-edges of the arms engaging behind the barbs 29 formed on the webs defining the channel. This completed assembly is shown on the left hand side of both Figures 2A and 2B.

The drilling of a hole through the base section 22 but centrally of the channel 27 is facilitated by the base section being profiled within the channel to have a V-shaped form. The side webs 28 defining the channel are equi-spaced to each side of this V-shaped form, which serves to centralise the drill bit.

It will be appreciated that the overall assembly may be completed in one of two ways. Either two holes could be drilled through the rafter and separately two holes are drilled through the eaves beam at appropriate positions, so that the bolts may be assembled to the rafter, "hereafter the rafter is fitted to the eaves beam. Altematively, the rafter could be held in the correct position on the eaves beam and then two holes drilled through both the rafter and the eaves beam. Once a hole has been formed through the rafter and eaves beam, a bolt may be fitted thereto in the manner described above. In either case, the 1s completion of the fixing of the rafter to the eaves beam may be performed solely from below, by running a nut up the portion of the bolt projecting below the load bearing surface 19 of the eaves beam 10. Once all of the rafters have appropriately been secured, each by means of two bolts, then the trim plate 13 may be fitted to the eaves beam, so concealing the bolts and nuts.

The rafters of Figures 2A and 2B differ only in that the rafter of Figure 2A has a central column 23 of a greater height than that of Figure 2B. This permits the accommodation of a thicker glazing panel (for example, six-wall polycarbonate glazing sheets, giving five cavities) as compared to the arrangement of Figure 2B which is able to accommodate only threewall glazing panels (that is, double cavity glazing). In all other respects, the rafter of Figure 2B corresponds to that of Figure 2A. -

Claims

1. A method of fixing a rafter to a support beam wherein the rafter has a generally-upward facing channel formed therealong which channel is defined by a pair of spaced side webs upstanding from a face of the rafter, comprising the steps of: - positioning the rafter on the support beam in the required position; to - drilling a hole substantially perpendicularly through the channel and into the beam; - inserting a bolt through the drilled hole so that the head of the bolt is located between the side webs of the channel and is prevented from turning thereby; - fitting a clip over the head of the bolt which clip engages the side webs to be retained thereby; and - threading a nut on to the part of the bolt projecting below the beam, to tighten the rafter to the beam.

2. A method of fixing a rafter to a support beam wherein the rafter has go a generally-upward facing channel formed therealong which channel is defined by a pair of spaced side webs upstanding from a face of the rafter, comprising the steps of: - drilling a hole substantially perpendicularly through the channel of the rafter at the required position along the length of the rafter; - inserting a bolt through the drilled hole so that the head of the bolt is located between the side webs of the channel and is prevented from turning thereby; - fitting a clip over the head of the bolt which clip engages the side webs to be retained thereby; - drilling a hole through the eaves beam at the location where the rafter is to be fixed; - positioning the rafter on the support beam with the bolt passing through the drilled hole in the eaves beam; and to - threading a nut on to the part of the bolt projecting below the beam, to tighten the rafter to the beam.

3. A method as claimed in claim 1 or claim 2, wherein the clip is generally U-shaped and has a base section from which extend opposed arms, the inside faces of the arms interengaging with the outside faces of the side webs.

4. A method as claimed in claim 3, wherein the outside face of each side web has a rib extending therealong, and each arm of the clip is held to the channel by engaging an inwardly-directed abutment on each arm behind the respective rib.

5. A method as claimed in claim 4, wherein each said rib is of barb shaped cross-section whereby as the clip is pressed into engagement with the channel, the abutment of each arm rides over the respective rib. - 12

6. A method as claimed in any of the preceding claims, wherein the nut is threaded on the bolt solely from below the support beam.

7. A method as claimed in any of the preceding claims, wherein the rafter has a second channel extending therealong parallel to the first- mentioned channel, the second channel being similarly configured to the first-mentioned channel and the rafter is fixed to the support beam by a second fixing arrangement provided by the same method as the firstmentioned arrangement.

8. A method of fixing a rafter to a support beam and substantially as to hereinbefore described, with reference to the accompanying drawings.

9. A fixing arrangement for attaching a rafter to a support beam, in which arrangement: - the rafter is provided with a generally-upward facing channel extending therealong and defined by a pair of spaced side webs upstanding from a face of the rafter, - a bolt passes through aligned holes in the channel and the support beam, the head of the bolt locating in the channel between the side webs thereof and being prevented from turning thereby; - a clip is fitted over the head of the bolt which clip engages the go side webs to be retained thereby; and - a nut is threadingly engaged with the part of the bolt projecting below the beam, to clamp the rafter to the beam. - 13

10. A fixing arrangement as claimed in claim 9, wherein the clip is generally channel-shaped.

11. A fixing arrangement as claimed in claim 10, wherein the clip has a base section which overlies the head of the bolt and a pair of opposed arms each of which lies alongside the outside face of the respective side web.

12. A fixing arrangement as claimed in claim 10 or 11, wherein the outside face of each side web has a rib extending therealong, and each arm of the clip has an inwardly-directed abutment which engages behind to the respective rib to hold the clip engaged with the channel.

13. A fixing arrangement as claimed in claim 12, wherein each said rib is of barb-shaped cross-section to facilitate the engagement of the clip abutment behind the rib.

14. A fixing arrangement as claimed in claim 13, wherein said abutment on each arm of the clip is defined by the free longitudinal edge of each arm being fumed inwardly towards the opposed arm.

15. A fixing arrangement as claimed in claim 14, wherein the clip comprises a sheet metal pressing.

16. A fixing arrangement as claimed in any of claims 9 to 15, wherein so the rafter has a second channel extending therealong parallel to the first- mentioned channel, the second channel being similarly configured to the - 14 first-mentioned channel whereby the rafter is secured to the beam by two similar and parallel fixing arrangements.

17. A fixing arrangement for attaching a rafter to a support beam and substantially as hereinbefore described, with reference to and as illustrated in the accompanying drawings.