AU3254100A - Fence post - Google Patents

Description

S&F Ref: 507227

AUSTRALIA

PATENTS ACT 1990 COMPLETE

SPECIFICATION

FOR A STANDARD

PATENT

ORIGINAL

a Name and Address of Applicant Actual Inventor(s): Address for Service: Invention Title: Gram Engineering Pty. Ltd.

16 Cullen Place Smithfield NSW 2164 Australia Ernest Dobbie Spruson Ferguson St Martins Tower 31 Market Street Sydney NSW 2000 Fence Post ASSOCIATED PROVISIONAL APPLICATION

DETAILS

[33 Country [31] Applic. No(s) Ali PQ0210 [32] Application Date 06 May 1999 The following stateent i a full description of this invention, including the best method of performing it known to me/us:- 8

J

1 FENCE

POST

Technical Field The present invention relates to fencing, and in particular relates to a fence post suitable for use in a roll formed modular metal fence system.

Background of the Invention A currently available form of fencing, known as a roll formed modular metal fencing system is depicted in Figure 1. The fencing system is constructed of sheet steel roll formed vertical C-channel posts 10 secured to the ground at regular intervals with sheet steel fencing panels 20 secured between the C-channel posts and roll formed top and 1o bottom channel rails 30, 40. During construction of such a fence, a bottom channel rail :is positioned between each adjacent pair of C-channel posts 10, the ends of the bottom channel rail 40 are inserted into the cavity 11 of the respective adjacent C-channel post (depicted in detail in Figure 2) and fastened to the opposing side walls 12 thereof by means of fasteners 45. A fencing panel 20 is then positioned between the adjacent

C-

I. 5s channel posts 10 with its side and lower edges respectively received in the cavities of the adjacent C-channel posts 10 and the bottom channel rail 40 extending therebetween.

A

top channel rail 30 is then placed between the adjacent C-channel posts 10 with its cavity over the top of the fencing panel 20 so as to captively retain the fencing panel 20 between the channel rails 30, 40 and C-channel posts 10. The ends of the top channel rail 30 are 20 inserted into the cavity 11 of the respective adjacent C-channel post 10 and fastened to the opposing side walls 12 thereof by means of fasteners 45 in a similar manner to the bottom channel rail A typical standard C-channel post 10, which is roll formed of pre-painted sheet steel, has a constant cross section as depicted in Figure 2. Each opposing side wall is deformed out of plane adjacent the free edge 13 thereof so as to form a stiffening region 14. The overall rigidity of the section is, however, somewhat limited. At the end of a given section of fencing, stiffening of the end post 10 may be required. Such stiffening is typically provided in the form of a square RHS post 50 fastened to the rear wall 15 of the end C-channel post 10 by way of fasteners 60 as depicted in Figure 3. Production of two separate elements and fastening of the same, however, adds to the expense of the fence, both in component manufacturing and fence construction.

Between adjacent fencing panels 20, two C-channel posts 10 are typically fastened rear wall 15 to rear wall 15 as depicted in Figure 4. In certain circumstances this [I:\DayLib\LIBLL]02114.doc:KEH I I 2 structure may also be of insufficient rigidity, requiring the fastening of a third element, typically another square RHS post 50, between the two C-channel posts 10 as depicted in Figure 5. Again, the requirement for production of a third element and fastening of the same adds to the expense of the fence.

The square RHS posts 50 are typically formed by roll forming unpainted sheet steel, seam welding the formed section to close the square cross-section, then powder coating the formed and welded post. As the powder coating process is carried out separately to the pre-painting of the C-channel posts, it is difficult to obtain an accurate colour match between the square RHS and C-channel posts, often providing an 1o unacceptable finish.

Object of the Invention *It is the object of the present invention to overcome or substantially ameliorate at least one of the above disadvantages or to provide a useful alternative.

ooo Summary of the Invention There is disclosed herein a roll formed metal section, said section being formed as an integral longitudinally extending, constant cross section channel having a rear wall adjoining opposing side walls, a front opening of said channel being defined between free edges of said side walls, each of said side walls being formed with a folded projection o• projecting inwardly of said channel, each of said folded projections comprising front and 20 rear wall segments joined by an end wall segment, said end wall segments being adapted to abut so as to enable force transfer therebetween, and wherein said front wall segments are located a predetermined distance from said free edges for limiting the depth to which a member is able to pass into said channel through said opening, while said rear wall segments are spaced from said rear wall.

Preferably said front and rear wall segments of each said folded projection abut adjacent an outward end of the respective projection.

Preferably said projections are each formed with a bulbous region defined by the respective projection end wall segment and adjoining portions of the respective projection front and rear wall segments.

Preferably said projection end wall segments are each provided with complementary interlocking means.

Preferably said interlocking means comprise mating undulations.

[I:\DayLib\L I,L]021 14.doc:KE EH Alternatively said interlocking means comprise complementary groove and tongue means.

Alternately said projection end wall segments are generally planar.

Preferably said planar projection end wall segments end abut over a depth of at s least one fifth of the width of said opening.

Preferably said projection front wall segments are substantially planar.

Preferably each of said side walls is formed to provide a stiffening region toward the respective free edge.

Preferably said section is roll formed from prepainted sheet steel.

0 Preferably the section is a fence post.

Brief Description of the Drawings Preferred forms of the present invention will now be described by way of ,example only with reference to the accompanying drawings wherein: Figure 1 is a front elevation view of a prior art fence; S, 15 Figure 2 is a plan view of a prior art C-channel fence post; ,Figure 3 is a plan view of a prior art assembly of a C-channel fence post and a square post; Figure 4 is a plan view of a prior art assembly of two C-channel fence posts; Figure 5 is a prior art assembly of two C-channel fence posts and a square post; Figure 6 is a plan view of a fence post according to a first preferred embodiment of the present invention; *Figure 7 is a plan view of the fence post of Figure 6 assembled with a channel rail; Figure 8 is a plan view of a fence post according to a second embodiment of the present invention; Figure 9 is a plan view of a fence post according to third embodiment of the present invention; and Figures 10 through 19 are plan views of fence post according to various alternative embodiments of the present invention.

3o Detailed Description of the Preferred Embodiments With reference to Figure 6, the fence post 100 of a first embodiment of the present invention is roll formed of sheet metal material as an integral longitudinally extending constant cross section channel. The post 100 has a rear end wall 105 adjoining [I:\DayLib\LIBLL]02 114.doc:KEH opposing side walls 102. A front opening 106 of the channel is defined between free edges 103 of the side walls 102. The fence post 100 is typically roll formed from sheet steel, which will preferably be supplied with a pre painted finish.

Each of the first and second side walls 102 is formed with a folded projection 108 projecting inwardly of the channel. Each folded projection comprises front and rear wall segments 108a, 108c joined by an end wall segment 108b. The end wall segments 108b are adapted to engage, as depicted in Figure 1, so as to enable force transfer between the end wall segments 108b, thereby transferring load across the channel through the projections 108.

As a result of the springback effect associated with operations such as roll forming of sheet metal materials, the projection end portions 108b may not actually engage prior to use, with a small gap between the projection end portions being typical o *"•until a fence channel rail 30,40 is fastened to the post 100 as depicted in Figure 7, *drawing the opposing side walls 102 and projections 108 together into an abutting 15 Is relationship. The channel rail 30, 40 is inserted through the opening 106 and fastened to the front region of the side walls 102 of the channel post 100 with fasteners as per the standard C-channel post 10.

.The projection front wall segments 108a are located a predetermined distance from the free edges 103 of the side walls 102 and can be seen in Figure 7 to limit the depth to which a fence channel rail 30 may pass into the channel. The projection front wall segments 1 08a thus act in much the same manner as the rear wall 15 of the standard C-channel post 10 in this regard. The projection front wall segments 108a will typically be generally planar so as to approximate the rear wall of the standard C-channel post and not interfere with the fitting of channel rails 30, It can be seen that a single fence post 100 approximates the current twin post assembly of Figure 3 formed of a C-channel post 10 and RHS post 50. Two components are thus replaced with a single component. Having the projections 108 abut enables transfer of load therebetween, ensuring the structural rigidity of the post 100. The typical major service loading experienced by the fence posts is a bending load due to gusts acting on the fence. The ability to transfer load between the projections 108 is necessary to counter the bending loads and avoid premature buckling of the post 100. The service load acting on the fence post 100 is typically eccentric, resulting in a degree of twist of the section. There will thus be a tendency for the projections 108 to slide with respect to one another. Having end wall segments 108b engage, as opposed to merely having the sharp [I:\DayLib\LIBLL 2I 14.doc:KEH edges of sheet wall projections meet at a point, ensures that a degree of slip is possible without the projections slipping past each other out of engagement.

Replacing the assembly of Figure 3 with a single roll formed fence post 100, as well as reducing cost of component manufacture and fence construction, facilitates the colour matching of components, as all components can be roll formed of sheet metal which has all been pre-painted through the same process and same batch of paint.

As well as replacing the assembly of Figure 3 with a single fence post 100, the current assembly of either of Figures 4 and 5 can be replaced with an assembly of one fence post 100 fastened rear wall to rear wall with a standard C-channel post 10. Such a 10 two component assembly will provide an intermediate post assembly between fencing panels 20 which has a strength and rigidity in excess of the current two component assembly of Figure 4 and close to that of the current three component assembly of Figure If additional strength and rigidity is desired, two of the fence posts 100 of the first embodiment can be fastened rear wall 105 to rear wall 105.

The side walls 102 will typically be formed with stiffening regions 113 toward °o the free edge 103 as per the standard C-channel post 10. The side walls 102 will typically be deformed out of plane in any number of known ways to provide the stiffening region 113 which increases the overall rigidity of the fence post.

oo* The various bends formed during the roll forming of the projections 108 will preferably have an internal radius exceeding three times the thickness of the sheet *material so as to avoid cracking of the pre-painted finish. Here the sheet thickness is approximately 0.9 mm and the bend internal radii are approximately 3.0 mm. All other radii of the fence post 100 cross section should also exceed three times the sheet thickness when pre-painted sheet steel is being employed. The overall cross section of the preferred fence post 100 measures approximately 87 mm from the rear wall 105 to the side wall free edges 103, with the side walls 102 being separated by approximately 50 mm for reception of a 50 mm wide channel rail 30, In the preferred first embodiment, the projection front and rear wall segments 108a, 108c of each respective projection abut adjacent the outward end 108d thereof. This ensures that the exterior profile presented by each side wall 102 is closed, with the line defined by the abutting wall segments 108a, 108c appearing, from the exterior, much the same as a rear wall to rear wall joint between any of the various forms of post 10, 50, 100.

Each of the projections 108 of the first embodiment fence post 100 is formed with a bulbous region 109 defined by its end wall segment 108b and adjoining portions of [I:\DayLib\LIBLL]02114.doc:KEH the projection front and rear wall segments 108a, 108c. Forming the bulbous portion 109 enables the provision of an end wall segment 108b of increased depth (length measured from the front to rear wall segments 108a, 108c). Any increased depth of the projection end wall segments 108b will reduce the chance of them slipping past one another when subjected to twisting loads. It is preferred that the projection end wall segments engage over a depth of at least one fifth of the width of the opening 106.

The projection end segments 108b are provided with complementary interlocking means, which are here in the form of mating undulations. The provision of such interlocking means helps resist any twisting loads which tend to make the projection o end wall segments 108b slide over each other.

An alternative interlocking means is provided in the second embodiment fence post 200 of Figure 8. The projection end wall segments 208b are provided with a tongue 220 and groove 221 arrangement, providing a more secure interlock.

Rather than providing the projection end wall segments with complementary ;1 5 interlocking means, a third embodiment post 300, depicted in Figure 9, contemplates having planar projection end wall segments 308b. Friction acting between the abutting end wall segments 308b is relied on here to inhibit relative sliding of the end wall *segments 308b. Again it is preferred that the planar end wall segments 308b abuttingly engage over a depth of at least one fifth of the width of the opening 306 so as to provide a significant friction bearing surface and so that a large sliding displacement is required to cause the two end wall segments 308b to disengage. Smaller engagement depths can, however, still provide effective results.

Figures 10 through 19 depict various other variations of fence post contemplated by the current invention. It can be seen that the projections can take a number of varying forms and sizes, each comprising a front, rear and engaging end wall segments. The person skilled in the art will appreciate that many further variations will also be possible.

The above described preferred embodiments, that is the various fence posts, are merely examples of a roll formed metal section which may be employed in other instances apart from fencing. For example, the metal section may be employed to support sheet material such as glass, fibreboard and plaster, as typically used in the construction of buildings.

[I:\DayLib\LIBLL]02 114.doc:KEH

Claims (9)

1. A roll formed metal section, said section being formed as an integral longitudinally extending, constant cross section channel having a rear wall adjoining opposing side walls, a front opening of said channel being defined between free edges of said side walls, each of said side walls being formed with a folded projection projecting inwardly of said channel, each of said folded projections comprising front and rear wall segments joined by an end wall segment, said end wall segments being adapted to abut so as to enable force transfer therebetween, and wherein said front wall segments are located a predetermined distance from said free edges for limiting the depth to which a member is 0i able to pass into said channel through said opening, while said rear wall segments are spaced from said rear wall. The roll formed metal section according to claim 1, wherein said front ~and rear wall segments of each of said folded projections abut adjacent an outward end of o• S 9 the respective projection. I5

3. The roll formed metal section according to claim 2, wherein said projections are each formed with a bulbous region defined by the respective projection end wall segment and adjoining portions of the respective projection front and rear wall 9 9 segments. too.

4. The roll formed metal section according to claim 3, wherein said projection end wall segments are each provided with complementary interlocking means. The roll formed metal section according to claim 4, wherein said *bointerlocking means comprise mating undulations.

6. The roll formed metal section according to claim 4, wherein said interlocking means comprise complementary groove and tongue means.

7. The roll formed metal section according to claim 3, wherein said projection end wall segments are generally planar.

8. The roll formed metal section according to claim 7, wherein said planar projection end wall segments end abut over a depth of at least one fifth of the width of said opening.

9. The roll formed metal section according to any one of claims 1 to 8, wherein said projection front wall segments are substantially planar. The roll formed metal section according to any one of claims 1 to 9, wherein each of said side walls is formed to provide a stiffening region toward the respective free edge. [I:\DayLib\LIBLL02I

14.doc:KEH 11. The roll formed metal section according to any one of claims 1 to wherein said section is roll formed from prepainted sheet steel. 12. The roll formed metal section according to any one of claims 1 to 11, wherein the section is a fence post. 13. A roll formed metal section, substantially as herein described with reference to any one of the embodiments of the invention shown in the accompanying drawings. Dated 5 May, 2000 Gram Engineering Pty. Ltd. 10 Patent Attorneys for the Applicant/Nominated Person SPRUSON FERGUSON 0 0 [I:\DayLib\LIRLL]02

114.doc:KEH