STEP IRON IMPROVEMENTS

Abstract

A step iron for a concrete structure, the step iron comprising a body and a leg; the body and leg each comprising a metal core and at least partially encapsulated in a polymer material; the body comprising a tread length to enable a user to use the step iron for climbing; the leg comprising a proximal end nearer the body and a distal end; the distal end of the leg comprising an end section to abut a complementary section of an insert which is fixable and embeddable within a concrete structure; a fixing means mounted on the leg to enable reversible engagement with a complementary section of the insert.

Claims

1. A step iron for a concrete structure, the step iron comprising a body and a leg; the body and leg each comprising a metal core and at least partially encapsulated in a polymer material; the body comprising a tread length to enable a user to use the step iron for climbing; the leg comprising a proximal end nearer the body and a distal end; the distal end of the leg comprising an end section to abut a complementary section of an insert which is fixable and embeddable within a concrete structure; a fixing means mounted on the leg to enable reversible engagement with a complementary section of the insert.

2. (canceled)

3. A step iron according to claim 1 comprising a metal core fully encapsulated in a plastic material;

4. (canceled)

5. A step iron according to claim 1 wherein the distal end of each leg comprises an end section to abut an insert which is fixable within formwork and embeddable within a concrete structure without protruding therefrom.

6. A step iron according to claim 1 comprising a locking ring centrally located on the axis of each leg just proximal to the end section.

7. A step iron according to claim 1 comprising a plastic ferrule nut slidably mounted on each leg proximal to a locking ring, such nut comprising an external thread which is complementary to that of the insert and a means for gripping the nut so that the nut can be tightened on the thread of said insert so as to securely but reversibly hold the step iron in place on the concrete structure.

8. A step iron according to claim 1 comprising vertical upstands located substantially laterally on the tread length to prevent a person's foot slipping off the end of the step iron.

9. (canceled)

10. A step iron according to claim 1 wherein the distal end of the leg comprises an end section to abut a complementary section of a substantially ring-shaped polypropylene or polyethylene insert which comprises an internal thread and a plurality of apertures to enable it to be fixed within formwork and embeddable within a concrete structure without protruding therefrom.

11. A step iron according to claim 1 comprising a locking ring centrally located on the axis of each leg just proximal to the end section, the locking ring being able to withstand a force of 5 kN.

12. A step iron according to claim 1 comprising a plastic ferrule nut slidably mounted on each leg proximal to each locking ring, such nut comprising an external thread which is complementary to that of the insert and a plurality of pre-formed holes for gripping the nut so that the nut can be tightened on the thread of said insert so as to securely but reversibly hold the step iron in place on the concrete structure in such a manner so that the security of such hold is visible to the naked eye.

13. A step iron according to claim 1 comprising a ferrule nut and wherein the nut comprises a tamper-evident cavity adapted to disfigure said plastic of the nut if an attempt is made to remove the step after initial installation.

14.-16. (canceled)

17. A step iron apparatus for a concrete structure comprising an insert and a step iron: the insert being fixable and embeddable within a concrete structure; the step iron comprising a body and a leg; the body and leg each comprising a metal core and at least partially encapsulated in a polymer material; the body comprising a tread length to enable a user to use the step iron for climbing; the leg comprising a proximal end nearer the body and a distal end; the distal end of the leg comprising an end section to abut a complementary section of the insert; a fixing means mounted on the leg to enable reversible engagement with a complementary section of the insert.

18. (canceled)

19. A step iron apparatus according to claim 17 comprising a metal core fully encapsulated in a plastic material;

20. (canceled)

21. A step iron apparatus according to claim 17 wherein the distal end of each leg comprises an end section to abut an insert which is fixable within formwork and embeddable within a concrete structure without protruding therefrom.

22. A step iron apparatus according to claim 17 comprising a locking ring centrally located on the axis of each leg just proximal to the end section.

23. A step iron apparatus according to claim 17 comprising a plastic ferrule nut slidably mounted on each leg proximal to a locking ring, such nut comprising an external thread which is complementary to that of the insert and a means for gripping the nut so that the nut can be tightened on the thread of said insert so as to securely but reversibly hold the step iron in place on the concrete structure.

24. step iron apparatus according to claim 17 comprising vertical upstands located substantially laterally on the tread length to prevent a person's foot slipping off the end of the step iron.

25. (canceled)

26. A step iron apparatus according to claim 17 wherein the distal end of the leg comprises an end section to abut a complementary section of a substantially ring-shaped polypropylene or polyethylene insert which comprises an internal thread and a plurality of apertures to enable it to be fixed within formwork and embeddable within a concrete structure without protruding therefrom.

27. A step iron apparatus according to claim 17 comprising a locking ring centrally located on the axis of each leg just proximal to the end section, the locking ring being able to withstand a force of 5 kN.

28. A step iron apparatus according to claim 17 comprising a plastic ferrule nut slidably mounted on each leg proximal to each locking ring, such nut comprising an external thread which is complementary to that of the insert and a plurality of pre-formed holes for gripping the nut so that the nut can be tightened on the thread of said insert so as to securely but reversibly hold the step iron in place on the concrete structure in such a manner so that the security of such hold is visible to the naked eye.

29. A step iron apparatus according to claim 17 comprising a ferrule nut and wherein the nut comprises a tamper-evident cavity adapted to disfigure said plastic of the nut if an attempt is made to remove the step after initial installation.

30.-47. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0058] FIGS. 1A to 1E depict various aspects of a preferred embodiment of the step iron component of the invention.

[0059] FIGS. 2A to 2C depict various aspects of a preferred embodiment of the step insert component of the invention.

[0060] FIGS. 3A to 3E depict various aspects of a preferred embodiment of the ferrule nut component of the invention

[0061] FIG. 4 depicts the assembly of the components described in FIGS. 1A to 3E.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0062] It is convenient to describe the invention herein in relation to particularly preferred embodiments. However, the invention is applicable to a wide range of embodiments and it is to be appreciated that other constructions and arrangements are also considered as falling within the scope of the invention. Various modifications, alterations, variations and or additions to the construction and arrangements described herein are also considered as falling within the ambit and scope of the present invention.

[0063] According to some preferred embodiments, the invention consists of an improved steel reinforced, plastic encapsulated step iron used in combination with threaded plastic step inserts and a ferrule nut. The plastic step inserts are cast into the walls of the concrete structures. The step legs are then inserted into the step plug inserts and the ferrule nut is tightened to secure the step in place. The system of the invention is much safer than prior art systems, in particular in relation to minimum pull-out force.

[0064] Since the step is secured by means of a threaded system rather than through permanent embedment into a concrete wall it can be easily removed by persons working inside the structures, allowing them enough working space inside the structures. The steps can be easily re-inserted while being able to guarantee ongoing compliance with pull-out force safety requirements.

[0065] With reference to FIG. 1, the step iron component of the invention comprises a generally U-shape design consisting of 2 legs (1) and a tread length (2). The structure of this step is a steel reinforced core fully encapsulated in plastic, preferably high impact polypropylene. Other types of plastic are also suitable, for example, polyethylene or polypropylene. The steps are encapsulated to prevent corrosion of the steel core and to ensure there is no electrical conductivity in the steps. From a manufacturing standpoint, some plastics can be less preferable, for example standard polypropylene can be too brittle under impact and can crack and some plastics can be ‘too slippery’. In some embodiments, steps can be manufactured from steel, cast iron or aluminium with corrosion protection applied. It has been found that plastic encapsulation through plastic injection moulding is preferable. By using a mould, the manufacturing process can be undertaken with very tight tolerances, in particular with the threaded components. It is possible but less preferable to use steel, aluminium or cast iron, however it is more difficult to obtain such tight tolerances and it may necessitate that the components are hand-made with more variance in the end product. Further, using these materials without plastic encapsulation creates the potential for corrosion, compromising structural integrity of the materials and therefore creating safety risks.

[0066] The step iron also comprises vertical upstands (3) that prevent a person's foot from slipping off the end of the step iron when in use. Vertical upstands according to the invention are preferably at least 20 mm in height, and preferably in the range 20 to 30 mm and in some embodiments in the range 20 mm to 50 mm. A particularly preferred embodiment as depicted in FIG. 1d is 25 mm in height. The length of the vertical upstands (measurement along the leg (1) of the step iron) is preferably at least 50 mm, and preferably in the range 55 to 65 mm. It has been found that a length of about 58 mm or 59 mm is preferred and a length of 58.79 mm is depicted in FIG. 1D.

[0067] Additionally, the rear of the tread length (2) incorporates a series of raised profiles (5) to improve the handhold of a person as they descend and ascend into and out of the structures incorporating the invention.

[0068] The legs of the step iron also comprise a locking ring (4) that forms part of the locking mechanism for the step. In some preferred embodiments, the locking rings are 40 mm in diameter and 6.84 mm thick (refer dimensions shown in FIG. 1A). However, it will be appreciated that a range of suitable dimensions are possible, for example approximately 30 mm to 50 mm in diameter and approximately 5 to 10 mm thick. For safety reasons, the locking ring should ideally withstand a minimum force of 5 kN (500 kg).

[0069] With reference to FIG. 2, the step insert component of the invention is comprised of plastic, preferably polypropylene that is designed to be cast into the walls of the concrete structures. Polypropylene is preferable as this component will be made by plastic injection moulding and for the same reasons we use polypropylene to encapsulate the steel core of the step (as described above). Steel is less preferable as each item would most likely have to be hand made and therefore tolerances would be out, in particular for the threaded component. Additionally within concrete structures exposed steel is not optimal as it will rust and risks transferring the rust to the steel reinforcing inside the concrete of the structure causing concrete cancer and compromising the integrity of the structure. Further, this would also potentially cause electrical conductivity issues as described above for the step component.

[0070] In some embodiments, the step inserts can be fixed to the internal formwork of the structure prior to concrete placement using nails for wooden formwork and magnets for steel formwork.

[0071] In one preferred embodiment, the insert comprises a threaded recess (6) and a cavity (7) that is designed to accept the legs of the step iron component (1). Further, the insert contains holes in the exterior (8) designed to allow the steel reinforcement of the concrete structures to pass through, thereby securing the insert into the wall of the structure.

[0072] In some embodiments, steps would first be fixed to the inner formwork using nails or magnets. As the person constructing the structure builds the steel reinforcement they would pass reinforcement bars through these holes and tie this to the reinforcement of the structure. It should be noted that this is not a critical step and it could potentially work without the exterior holes but this would provide additional support to ensure that the step inserts don't move when the concrete is placed into the formwork.

[0073] With reference to FIG. 3, the ferrule nut component of the invention is preferably comprised of plastic, preferably polypropylene consisting of a threaded exterior face (9) that matches the threaded recess of the step insert (6), a central hole (10) designed to fit over the leg of the step iron (1) above the locking ring (4). There are also included pre-formed holes (11) to allow the tightening of the ferrule nut into the threaded section of the step insert (6).

[0074] These pre-formed holes have an additional cavity at the rear (12) (see FIG. 3C) that will disfigure if attempts are made to remove the step after initial installation, thereby showing evidence of tampering. The cavity as shown in FIG. 3C is approximately 10 mm long. Turning to FIG. 3A it is evident that the hole at the top is 5 mm diameter. However the plastic at the surface is only approximately 2 mm thick. When force is applied against it in order to loosen the step and remove it, that thin piece of plastic will deform and elongate from a round 5 mm diameter hole to the 10 mm long cavity.

[0075] FIG. 4 depicts an example embodiment of the invention as an assembly of the components described in FIGS. 1 to 3. The assembly depicts how the ferrule nut shown in FIG. 3 fits over the leg of the step iron insert (1) above the locking ring (4). The assembly contains an exploded view which shows how the leg of the step iron (1) component is inserted into the step insert until the locking ring (4) seats hard inside the cavity (7). The ferrule nut is then tightened using the pre-formed holes (11) until the nut presses hard against the locking ring (4) thereby securing the step in place. Item (13) depicts how this preferred embodiment of the invention appears once the nut has been tightened.

[0076] In practice, the invention can for example be installed as follows: [0077] (a) the step inserts (FIG. 2C) are fixed to the internal formwork of the concrete structure using nails for wooden formwork or magnets for steel formwork. The location of the step inserts, vertical spacing etc. within the structure itself are done in accordance with standard safety principles and the requirements of the particular site. [0078] (b) Steel reinforcement is passed through the exterior holes of the step insert and tied into the steel reinforcement of the structure. [0079] (c) After the concrete is placed into the formwork and cured the formwork is removed, thus exposing the opening of the step insert on the inside face of the structure walls. [0080] (d) The legs of the step are inserted into the recess of the step insert until the locking ring is seated hard inside the step insert. [0081] (e) Using the appropriate tool, the ferrule nut is tightened until it is secure against the locking ring.

[0082] Example of manufacture method.

[0083] The steel core may for example be comprised of a standard straight rectangular section of steel. It is then cut to the desired length and bent into a U-shape. It is then inserted into a plastic injection mould with the first moulding encapsulating the step iron legs and locking ring. It is then removed from the mould and the ferrule nuts are placed onto the legs. The step is then placed back into the mould and the remainder of the step is encapsulated through plastic injection moulding.

[0084] An example method for this step is as follows:

[0085] (a) opening the ejection half and injection half of the mould body and inserting the step iron core into the injection half of the mould body;

[0086] (b) holding the core of the step iron in place using magnets at the end of each leg of the step iron;

[0087] (c) closing the ejection half and the injection half of the mould body so as to form a mould cavity enclosing the tread length and each leg of the step iron. The cavity formed around each step leg terminates at a point above the locking rings to allow the ferrule nut to be placed over the step legs after the first injection process;

[0088] (d) injecting a molten material, preferably high impact polypropylene into the mould cavity whereby the material flows into the mould cavity evenly, encapsulating the core of the step iron comprising the tread length and a portion of the each step leg to a position above the locking ring, leaving a portion of the steel core on each leg exposed;

[0089] (e) opening the ejection half and injection half of the mould body and ejecting the step iron comprising the encapsulated tread length and a portion of each step leg to a position above the locking ring;

[0090] (f) sliding a ferrule nut over each step leg. The ferrule nut is formed in a separate injection mould in a single injection process;

[0091] (g) re-positioning the step iron and gripping via a bracket to secure the tread length and strong magnets to grip each step leg through the injected plastic along the leg;

[0092] (h) closing the ejection half and the injection half of the mould body so as to form the mould cavity enclosing the end of each leg of the step iron extending only to the portion of each leg where the steel core remains exposed and includes a few millimetres of the previously injected plastic to meld together into one unit. The mould forms a seal at outside circumference of the portion of each step leg that has been encapsulated in the first injection moulding process;

[0093] (i) injecting a molten material, preferably high impact polypropylene into the mould cavity enclosing the end portion of each leg of the step iron and forming the locking ring on each step leg. Each step leg is encapsulated to a position extending from the termination of the moulding from the first process, ensuring an overlap in the moulding and the plastic melds together as a single piece, creating a complete seal encapsulating the entire steel core of the step insert;

[0094] (j)) opening the ejection half and injection half of the mould body and ejecting the step iron comprising of a fully encapsulated step iron, comprising a tread length and each step leg with a locking ring and ferrule nut integral to the whole assembly.