AU686694B2 - A support element - Google Patents

Description

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION 0 ~0 *0 *0 S S S

S.

S

S

o .5 S S 055 S S S *S S STANDARD PATENT Title of Invention: A SUPPORT ELEMENT Name of Applicant: ROCLA CONCRETE PIPES LIMITED

S.

5555 055505

S

The following description is a full description of this invention, including the best method of performing it known to me:- SJS C A SUPPORT ELEMENT The present invention relates to a method of forming a support surface within a concrete structure and to a support element for use in this method. The invention also relates to a concrete structure. The invention has particular application for use in concrete access chambers where support surfaces are required to secure a step iron in place and the invention is herein described in this context. However, it should be appreciated that the invention has broader application and is not limited to this particular use.

Concrete access chambers are we!l known and used in many structures to provide access to a work area or inspection site. Typically, an access chamber extends vertically and includes step irons secured to the inner chamber surface to provide the necessary structure to enable workers to climb up and down the chamber. These chambers are usually pre-formed with the step irons secured to the chamber surface after forming. In a previous arrangement, holes are formed or drilled into the chamber wall and the step irons are glued in place with epoxy or cement mortar. Alternatively, the step irons include threaded ends which are inserted through the holes in the chamber to protrude from the outer side of the chamber. The step irons are bolted in place by securing nuts to these protruding ends. Whilst these arrangements are effective, the separate formation of holes and fixing operations are often difficult and 20 time consuming.

An aim of the present invention relates to an improved system for forming a support surface in a concrete structure which ameliorates this problem.

5 Accordingly, in a first aspect, the present invention provides a support element 566° adapted to be embedded in a concrete structure, the element including: a hollow 8 25 housing having an inner wall defining a cavity, the inner wall being formed about a ,*SSS longitudinal axis and the housing further including spaced apart first and second ends extending across the axis, the first end incorporating a removable portion and the second end including an opening communicating with the cavity, the portion being configured to be removed on the application of force to the first end along the axis, wherein removal of the portion provides an opening into the housing to form a passage through the support element between its first and second ends, the passage being configured to enable a member to be inserted into the cavity along the axis.

SRA,

'T OP JH P10223,5 1011.97 The removable portion may be formed integral with the housing or may be formed separately and releasably secured to the housing. In a preferred arrangement, however, this removable portion is formed integral with the housing and joined to the housing by a frangible seam or join.

Preferably at least a first end of the housing is shaped to conform to a portion of the surface of the structure. This arrangement enables the removable portion to be located either substantially flush or parallel with the surface of the structure. Preferably, the a second end of the housing which is also arranged to conform to a portion of the surface of the structure.

In a preferred arrangement the two ends of housing are generally planar and intersect the longitudinal axis of the cavity at an angle to a plane normal to the longitudinal axis.

In a second aspect, the present invention provides a method of forming a concrete structure having opposite first and second surfaces and incorporating a :15 support surface extending befween said surfaces, the method including the steps of: 9o providing a support element including a hollow housing having an inner wall defining a cavity, the inner wall being formed about a longitudinal axis and the housing I further including spaced apart first and second ends extending across said axis, the first end incorporating a removable portion and the second end incorporating an opening 20 communicating with said cavity; 9 forming the concrete structure with the support element located therein, the support element being substantially covered by concrete and the cavity being t substantially free of concrete, the support element being positioned with the removable portion located at or near the first surface, and the opening in the second end .i:i 9 communicating with the second surface of the structure; removing said removable portion of said element by the application of forcealong said axis to form an opening in the first end communicating with said first surface .Ii to thereby provide said support surface extending between said first and second surfaces of said concrete structure through said cavity of said support element.

4 OJH P10223195 101197 Preferably the method further includes the steps of providing a mould having at least one mould surface, locating the support element at or adjacent the mould surface, and applying concrete to the mould surface to form the concrete structure.

With this arrangement, the removable ?ortion of the support element may be removed when the mould is stripped from the concrete structure or after curing of the structure. If the removable portion is joined to the housing by a frangible seam, the portion may be removed merely by being tapped out or tapped in to the cavity.

While the structure may be formed by casting concrete between two opposing mould surfaces, in a preferred arrangement a process of rotational moulding is used where only a single mould surface is provided against which concrete is located to form the structure. The mould may be rotated at high speed to generate a centrifugal force to cause the concrete to remain against the mould surface while it hardens, or an inner roller may be employed within the mould to compact the concrete against the mould surface.

15 In a yet further aspect, the present invention provides a concrete structure including opposite first and second surfaces and having at least one support element located in the structure between said surfaces, the support element including a hollow ~housing having an inner wall formed about a longitudinal axis and defining a cavity within said structure, the housing further including spaced apart first and second ends 20 extending across said axis and said structure further including a removable portion located at, or adjacent to, the first surface of said structure, and the second end 99oooe S including an opening communicating with said cavity and said second surface, wherein .9..99 the portion is configured to be removed by the application of force along said axis, to provide an opening at said first surface communicating with said cavity so as to form a passage between said first and second surface through said support element.

Preferably, the removable portion is located below the surface of the structure and is covered by a thin layer of concrete. This arrangement has the benefit that, whilst the removable portion may still be easily removed, the support element is in an inoperative mode and is concealed. This arrangement allows for greater flexibility in the use of pre-formed structures such as access chambers as the structure may be formed with a plurality of support elements and only those support elements required for a particular use of the structure need have their removable portions removed. The other support elements may remain inoperative and not affect the use of the structure, DJH Pt0223195 1011 97 The support element according to the present invention simplifies the system for forming support surfaces in a concrete structure. The elements can be easily cast into the structure with access gained to the inner cavity merely by knocking in or knocking out the removable portion of the element. This arrangement offers the flexibility of allowing multiple segments to be cast into the structure to provide various configurations of support elements in the final structure. Furthermore, the preferred form of the elements enables the structure to be formed with the support surface extending completely through the structure wall.

It will be convenient to hereafter describe embodiments of the invention in greater detail by reference to the accompanying drawings. The particularity of these drawings in related description is not to be understood as superseding the generality of the preceding broad description of the invention.

In the drawings: embodiment of the invention; ~Figure 2 illustrates an end view of the support element of Figure 1; Figure 3 illustrates the support element of Figure 1 located against a mould; o, Figure 3 illustrates the support element of Figure 1 located against a mould; Figure 3A illustrates a variation of the support element of Figure 1 located 20 against a mould; o •Figure 4 is a partial sectional view of the support element of Figure 1 formed S within a concrete structure; and Figure 5 is a partial sectional view of a concrete access chamber incorporating a r plurality of support elements of Figure 1.

In the drawings, the support element is in the form of a ferrule which is arranged to be embedded into a concrete structure. In the illustrated arrangement, the structure is in the form of a pre-formed concrete access chamber and the ferrule provides a support for an end of a step iron.

Figures 1 and 2 illustrate, respectively, a sectional side view, and an end view, of a ferrule P10223195 101197 The ferrule 10 comprises a hollow housing 11 having an inner wall 12 defining a cavity 13. The inner wall 12 is substantially cylindrical about a longitudinal axis 14 with the cavity 13 extending along this axis 14. First and second ends (15 and 16) of the housing intersect the axis 14 at an angle to a plane normal to the longitudinal access 14. The first end 15 incorporates an opening 17 into the cavity 13 and the second end incorporates a removable portion 18 which in the illustrated arrangement is formed integral with the housing 11 and joined to the housing by a frangible seam 19. Ribs 20 are formed on the outer surface 21 of the housing 11.

The ferrule 10 is typically made from a plastics material such as i polypropylene and is formed by a process of injection moulding.

The ferrule 10 is arranged to be embedded in a pre-formed concrete access chamber 22, as illustrated in Figure 5, and the method by which the ferrule is embedded into the chamber 22 is illustrated in Figures 3 and 4. In the 15 illustrated arrangement, the chamber is formed by a process of rotational moulding with the ferrule 10 being located against a mould 23 of the chamber 22 enabling the chamber to be formed with the ferrule in place.

•*oo In the arrangement shown the mould 23 is cylindrical and is rotatable about i the cylinder axis (not shown). The mould has an inner mould surface 24 against 2(0 which concrete is placed, and incorporates an aperture 25 arranged to receive a support arm 26 of a mechanical jig (not shown). The support arm is arranged to i support the ferrule 10 during forming and is inserted through the aperture 25 from the outer surface 27 of the mould 23 to extend from the mould surface 24. The ii ferrule 10 is then located over the support arm 26 such that the support arm 25 extends into the cavity 13 from the opening 17 with the first end 15 of the ferrule abutting the outer surface 24 of the mould 23. In this position the ferrule 10 is located in place relative to the mould 23 ready for forming and furthermore, this position ensures the opening 17 in the first end is covered to prevent the ingress..of concrete into the cavitj 13 from this opening. The opening 17 is not-!i] necessarily required in use of the ferrule 10 but is provided primarily to facilitate locating the ferrule in place on the mould surface 24. In an alternative arrangement (not shown) a ferrule may be provided without this opening. This latter arrangement may be provided if the ferrule is located on the mould surface 24 by other means such as through retaining elements or adhesive.

ne method of forming the chamber 22, the mould 23 is suspended horizontally on an inner roller (not shown). The roller is located within the mould 23 which includes end rings which support the mould 23 and maintain a radial gap between the mould and the roller.

The mould 23 is caused to rotate on rotation of the roller. Concrete is introduced into the radial gap at one end of the mould and the rotation of the mould and roller causes the concrete to be compacted against the mould surface 24 and around the ferrule 10. Sufficient concrete is provided to completely cover i the ferrule and form an inner surface 28 of the chamber. The ferrule 10 is arranged to be just covered by the concrete such that only a thin layer 29 ofconcrete separates the inner surface 28 of the chamber and the removable portion 18 of the ferrule. As the opening 17 in the first end is completely coveredi i and the removable portion 18 is in place, concrete is prevented from ingressing into the cavity 13.

~Once the concrete has cured sufficiently the mould and support arm 26 of the mechanical jig can be removed and re-used as required. The ferrule remains fully embedded in the chamber 22 with the ribs 20 assisting in securing--:: :20 the ferrule 10 in place.

In another method of forming the chamber, a roller is not used but the mould 23 is caused to rotate at a higher speed than in the previous method, to.

generate a centrifugal force at the mould surface 24. This force is sufficient to cause concrete introduced into the mould 23 to become compacted against the 25 mould surface 24. Once the concrete has hardened sufficiently, the mould and :iii! support arm can be removed as in the previous method.

As clearly illustrated in Figure 4, the ends 15 and 16 of the ferrule are I angled such that the ends substantially conform to the shape of the outer and inner surfaces 30 and 28 of the chamber. This enables the first end 15 to be. substantially flush with the outer surface 30 and the second end 16 incorporating the removable portion to be located substantially parallel with the inner surface 28. In practice the applicant has found an angle of approximately 200 from a 8 plane normal to the longitudinal axis 14 is suitable for the ends 15 and 16 to conform to the profile of the inner and outer mould surfaces.

Typically, the chamber 22 would be formed with a plurality of ferrules each covered at the inner surface 28 of the chamber by a thin layer of concrete.

In this arrangement the ferrules are non-operative. To enable a particular ferrule to become operative, the removable portion 18 of that ferrule is removed thereby providing an opening into the cavity 13. In the illustrated arrangement, this is: achieved by tapping in the removable portion by the applicaticr:., of pressure in the i] direction of the arrow or tapping out the removable portion by inserting an appropriate tool in the opening 17 and applying pressure to the portion 18 in the L direction of the arrow This force would break the frangible seam 19 and as the concrete (ias a low resistance to tensile force, the layer 29 would offer little resistance and collapse. Once removed, the opening 31 formed enables a step iron end 32 (as illustrated in Figure 5) to be inserted. A corresponding ferrule 10 :i 15 would be used to support the other end 33 of the step iron.

It should be appreciated that the ferrule may be formed in any suitable material and is not limited to be formed in concrete. Furthermore, the shape of i:i i the ferrule 10, as well as its location in a structure, and the method by which it is i located in place for forming may vary depending on its use. Similarly, the method by which the removable portion is removed could also vary. For example the mould may include inner and outer mould walls and the removable portion could. be formed as part of the inner mould wall and could be removed automatically on removal of the mould. Furthermore, with this latter arrangement, the removable portion may act as a spigot to support the ferrule in place during forming.

Alternatively, as illustrated in Figure 3A, the ferrule 10 includes openings at both the first and second ends (15, 16) and the support arm 26 includes an outer end i: 34 which forms the removable portion and prevents the ingress of concrete intothe ferrule through the opening at the second end 16. Once the support arm 26 is removed, a thin layer concrete remains covering the opening at the second end ii'i 16 of the ferrule.

It should be further appreciated that the removable portion 18 may form a continuation of the housing 11 and as such does not include a frangible seam. In 9 this arrangement, the portion 18 is removed typically through a drilling or cutting operation which cuts through the housing rather than through the application of i:11 force to tap out the removable portion on breaking of the frangible seam 19.

However, use of the frangible seam is preferred as it simplifies the process and ensures correct location and size of the opening which is formed.

The above arrangement enables a ferrule to be located in place on forming of the chamber. Furthermore, with the provision of a removable portion, ,-the ingress of concrete is prevented though the ferrule is able to become fully operable on removal of this portion. Also, additional ferrules may be included inthe chamber that may remain in an inoperative mode which will not affect the use of the chamber. By being able to choose the ferrules that are required, different arrangements of ferrules can be provided in the chamber using a single casting process. Consequently, this provides additional benefit for the mass production of the pre-formed chambers.

Finally it is understood that various alternatives, modifications and/or additions may be introduced into the construction arrangement of the parts previously described without departing from the spirit or ambit of the invention.

too.e

Claims (29)

1. A support element adapted to be embedded in a concrete structure, the element including a hollow housing having an inner wall defining a cavity, the inner wall being formed about a longitudinal axis and the housing further including spaced apart first and second ends extending across said axis, the first end incorporating a removable portion and the second end including an opening communicating with said cavity, said portion being configured to be removed on the application of force to said first end along said axis, wherein removal of said portion provides an opening into said housing to form a passage through said support element between its first and second ends, the passage being configured to enable a member to be inserted into the cavity along said axis.

2. A support element according to claim 1, wherein the removable portion is integrally formed with the housing and joined to the housing by a frangible seam.

3. A support element according to any preceding claim, wherein the first end is :l :15 generally planar and intersects the longitudinal axis at an angle to a plane normal to the S" longitudinal axis.

4. A support element according to any preceding claim, wherein both the first and second ends are generally planar and are disposed in substantially parallel planes. A support element according to any preceding claim, wherein the housing has an 20 outer surface having a ribbed profile.

6. A support element according to any preceding claim, wherein the element is formed from a plastics material.

7. A concrete structure including opposite first and second surfaces and having at least one support element located in said structure between said surfaces, the support 25 element including a hollow housing having an inner wall formed about a longitudinal axis and defining a cavity within said structure, the housing further including spaced apart first and second ends extending across said axis and said sructure further including a removable portion located at, or adjacent to, the first surface of said structure, and the second end including an opening communicating with said cavity and said second surface, wherein the portion is configured to be removed by the application of force along said axis, to provide an opening at said first surface communicating with said cavity so as to form a passage between said first and second surface through said support element. ~gRA4/ -az LU JH: P10223195 101197 7- 0 z

8. A concrete structure according to claim 7, wherein said first end of sa c4 housing is located at or adjacent to, said first surface and incorporates said removable portion.

9. A concrete structure according to claim 8, wherein the removable portion is integrally formed with the housing and joined to the housing by a frangible seam.

10. A concrete structure according to any one of claims 7 to 9, wherein the first end of the support element is configured to conform to the first surface of the structure such that the removable portion is located substantially flush with, or parallel to, said first surface.

11. A concrete structure according to any one of claims 7 to 10, wherein said second end is configured to conform to the second surface of the structure such that the second end is located substantially flush with the second surface.

12. A concrete structure according to either claim 12 or 13, wherein the structure is tubular having an inner surface comprising the first surface of the structure and an outer surface comprising the second surface of said structure. 15 13. A concrete structure according to any one of claims 7 to 12, wherein a plurality of support elements are formed within said structure enabling various configurations of cavities within said structure to be formed on the removal of removable portions of Sselected ones of the support elements.

14. A method of forming a concrete structure having opposite first and second 20 surfaces and incorporating a support surface extending between said surfaces, the method including the steps of: providing a support element including a hollow housing having an inner wall S" defining a cavity, the inner wall being formed about a longitudinal axis and the housing further including spaced apart first and second ends extending across said axis, the first end incorporating a removable portion and the second end incorporating an opening communicating with said cavity; forming the concrete structure with the support element located therein, the support element being substantially covered by concrete and the cavity being substantially free of concrete, the support element being positioned with the removable i portion located at or near the first surface, and the opening in the second end communicating with the second surface of the structure; removing said removable portion of said element by the application of force along said axis to form an opening in the first end communicating with said first surface 4U JH P10223195 101197 Q'r o- to thereby provide said support surface extending between said first and second I surfaces of said concrete structure through said cavity of said support element. A method according to claim 14, wherein said removable portion is removed by the application of force applied at the first surface of said structure.

16. A method according to claim 14, wherein said removable portion is removed by the application of force applied within the cavity.

17. A method according to any one of claims 14 to 16 further including the steps of: providing a mould having at least one mould surface; locating the second end of the support element at or adjacent to the mould surface; and casting concrete against the mould surface to form the second surface of the i, concrete structure.

18. A method according to claim 17, wherein the second end of the housing is. adapted to abut the mould surface.

19. A method according to claim 18 wherein the abutment of said second end against said mould surface is adapted to inhibit the ingress of concrete into the cavity on forming of the concrete structure.

20. A method according to any one of claims 17 to 19, wherein the support elements i is located against said mould by a retaining element extending from said mould through J i 20 said second opening and into the cavity of the support element.

22. A method according to claim 21, wherein the retaining element, when located within the cavity of the support element, is adapted to prevent the ingress of concrete into the cavity on forming of the concrete structure. o

23. A method according to any one of claims 18 to 22, wherein the structure formed i is tubular and wherein the mould is cylindrical having an inner surface extending about ^^l a cylinder axis, ard wherein concrete is applied to the inner surface and the mould is rotated about said cylinder axis to form said tubular structure. ;i

24. A method according to claim 23, wherein the inner surface of the tubular structure comprises the first surface f said structure.

25. A method according to any one of claims 18 to 24, wherein said removable portion is connected to, or forms part of, said mould. -o TH P10223195 10.11.97 ^r 13

26. A method according to any one of claims 14 to 24, wherein said removable portion is integrally formed with the housing and is joined to the housing by a frangible seam, and wherein said frangible seam is broken on removing said removable portion.

27. A method according to either claim 21 or 22, wherein said removable portion is connected to, or forms part of, said retaining element.

28. A method according to any one of claims 18 to 25; wherein said removable portion is removed on removal of the mould from said structure.

29. A method according to any one of claims 14 to 28, wherein said removable portion is adapted to be removed after curing of said structure.

30. A concrete structure formed by a method according to any one of claims 14 to 29.

31. A support element substantially as herein described with referencc to the accompanying drawings.

32. A method of forming a concrete structure substantially as herein described with 15 reference to the accompanying drawings.

33. A concrete structure substantially as herein described with reference to the accompanying drawings. DATED: 10 November 1997 PHILLIPS ORMONDE FITZPATRICK Attorneys for: ROCLA CONCRETE PIPES LIMITED P1022395 10.11.97 I i -r 14 ABSTRACT A method of providing a support surface in a concrete structure 22 is disclosed wherein a support element 10 is formed within the structure, the support element including a housing 11 having an inner wall 12 defining a cavity 13 and a removable portion 18. The support element is arranged such that the removable portion 18 is located at or adjacent the surface of the structure 28 and the support surface is provided by removing the portion 18 enabling the inner wall of the housing to provide the support surface for a member 31 inserted through the opening and received in the cavity. A support element 10 including a removable portion 18 which is suited for this method is also disclosed. A preformed concrete structure having a plurality of the support elements located below the surface of the concrete is also disclosed which is adapted to enable different configurations of support surfaces to be easily formed therein. The invention has particular application to concrete access chambers where support surfaces are required to secure step irons in place. S* S °o *0 S =IL