AU2014225271B2

AU2014225271B2 - Laddertube for underground raises

Info

Publication number: AU2014225271B2
Application number: AU2014225271A
Authority: AU
Inventors: Steven Peter Durkin
Original assignee: Hiram (Wa) Pty Ltd
Current assignee: Hiram (Wa) Pty Ltd
Priority date: 2013-03-07
Filing date: 2014-01-21
Publication date: 2017-05-11
Anticipated expiration: 2034-01-21
Also published as: AU2014225271A1; CL2015002252A1; BR112015019963B1; MX359617B; BR112015019963A2; MX2015011306A; WO2014134656A1

Abstract

A laddertube (10) for an underground raise is described having an elongate tube (12) made of a suitably rigid plastics material and adapted to be received in the raise. The tube (12) has a series of steps (14) moulded into an interior side wall thereof so as to form a ladder extending substantially the full length of the tube (12). Part only of the circumference of one end of the tube (12) is formed with an inside offset male edge (30) whereas the remainder of the one end is formed with a non-offset male edge (32). Part only of the circumference of the other end of the tube is formed with an outside offset female edge (34) whereas the remainder of the other end is formed with a non-offset female edge (36). In use, the inside offset male edge (30) can be received within the non-offset female edge (36) on the other end of an adjoining tube of identical design, and the outside offset female edge (34) can be received around the non-offset male edge (32) on the one end of the adjoining tube when the tubes are joined end to end. Amongst other advantages, this ensures that part of an internal wall of adjoining tubes is substantially smooth in the region of the join when the tubes are joined end to end.

Description

PCT/AU2014/000036 WO 2014/134656 1 “LADDERTUBE FOR UNDERGROUND RAISES”

Field of the Invention

The present invention relates to a laddertube for underground raises and relates particularly, though not exclusively, to a laddertube for underground 5 mine development.

Background to the Invention

In underground mine development a raise refers to a vertical or inclined bore or shaft excavated between levels or extending to the surface. Such raises are 10 provided for several different purposes, including the transportation of ore and waste rock, ventilation and as an emergency escape through which underground miners can escape to the surface in the event of an accident. For this purpose it is common for such underground escape raises to be provided with a ladderway to permit miners to climb up out of the mine. Conventional 15 ladderways are typically in the form of a pre-fabricated steel ladder surrounded with a steel mesh caging to provide a measure of protection for the miners as they climb the ladder.

Apart from the fact that such steel ladderways are heavy and expensive to manufacture and install, they are also difficult and expensive to maintain. The 20 ladderway is constantly exposed to groundwater and seepage which contribute to corrosion, particularly in highly saline groundwater conditions. Hence such steel ladderways require regular maintenance to ensure that salt and rust forming on the ladder rungs are cleaned away. It is often difficult to ascertain to what extent the steel has corroded over time and the safety of the 25 ladderway may be compromised. Furthermore, the steel mesh cage does not provide adequate protection for miners from rock falls.

Commonly owned International Application No PCT/AU2005/001815 describes a ladderway system for an underground raise, the system comprising an elongate tube with a ladder mechanically coupled to an interior PCT/AU2014/000036 WO 2014/134656 2 of the tube. The tube is of circular cross-section and is formed with a longitudinal slit along its entire length whereby the diameter of the tube can be adjusted to conform to the shape of the raise. Both the tube and the ladder are typically made from a suitable plastics material. The ladder is used for 5 mounting both the ladder and the tube to a wall of the raise. Whilst this system operates quite well, it is rather cumbersome to install. Furthermore the manufacture and installation of the ladder and the tube as separate components detracted from the modular design of the system.

Commonly owned International Application No PCT/AU2010/001753 10 describes an improved ladderway system for an underground raise, the system comprising an elongate tube made of a suitably rigid plastics material and adapted to be received in the raise, the tube having a series of steps moulded into an interior side wall thereof so as to form a ladder extending substantially the full length of the tube. Each of the steps has a hollow interior 15 and is formed with a pair of gussets within the hollow interior to provide additional strength and rigidity. The elongate tube is of circular cross-section and each step is in the form of a generally planar platform protruding inwards from the interior side wall of the tube. Whilst this laddertube provided significant improvements to the ladderway system, further improvements are 20 desirable to overcome problems with installation and/or drainage.

The present invention was developed with a view to providing a laddertube that provides improved joining of tube sections and/or improved drainage of water from each of the steps moulded into the interior side wall of the tube.

References to prior art documents in this specification are provided for 25 illustrative purposes only and are not to be taken as an admission that such prior art is part of the common general knowledge in Australia or elsewhere. WO 2014/134656 PCT/AU2014/000036 3

Summary of the Invention

According to one aspect of the present invention there is provided a laddertube for an underground raise, the laddertube comprising: an elongate tube made of a suitably rigid plastics material and adapted to be 5 received in the raise; the tube having a series of steps moulded into an interior side wall thereof so as to form a ladder extending substantially the full length of the tube; and part only of the circumference of one end of the tube is formed with an inside offset male edge whereas the remainder of the one end is formed with a non-10 offset male edge, and part only of the circumference of the other end of the tube is formed with an outside offset female edge whereas the remainder of the other end is formed with a non-offset female edge wherein, in use, the inside offset male edge can be received within the non-offset female edge on the other end of an adjoining tube of identical design and the outside offset 15 female edge can be received around the non-offset male edge on the one end of the adjoining tube when the tubes are joined end to end.

Preferably the inside offset male edge is provided along the part of the circumference of the tube corresponding substantially to the location of the series of steps moulded into the side wall of the tube. Advantageously the 20 outside offset female edge is provided along the part of the circumference of the tube corresponding substantially to a hanging wall side of the tube wherein, in use, the internal wall of the hanging wall side of adjoining tubes is substantially smooth in the region of the join when the tubes are joined end to end. 25 Advantageously the tube is of generally circular cross-section and each step is in the form of a generally planar platform protruding inwards from the interior side wall of the tube and wherein, in use, the part of the side wall of the tube in which the steps are formed normally rests against a footwall side of the raise. . Typically the cross-section of the tube bulges outwardly on either side near 30 the hanging wall side of the tube. Preferably an outer edge of each step is PCT/AU2014/000036 WO 2014/134656 4 substantially straight and is formed on a chord of the cross-section of the tube near the footwall side of the tube. Preferably the outer edge of each step is provided with a tread grip. Advantageously each step is provided with a void therethrough to allow for drainage of fluid. 5

Preferably the laddertube further comprises a pair of elongate handrails adapted to be attached to the steps and extending substantially the full length of the tube; and, wherein a plurality of the steps are formed with a pair of enlarged side wings, 10 the side wings each formed with a recess for receiving the respective handrails therein.

Preferably the pair of enlarged side wings is provided on selected steps only i with one or more steps absent the enlarged side wings provided there between. Typically each handrail is in the form of a substantially rigid member 15 of circular cross-section having an outside diameter that can be readily gripped by a person’s hand. Preferably the handrails are manufactured from a similar suitably rigid plastics material as the tube. Preferably each handrail is formed with a protruding portion of reduced diameter at a top end, which is adapted to be received in a matching recess provided in a bottom end of a 20 corresponding handrail on an adjacent tube.

According to another aspect of the present invention there is provided a laddertube for an underground raise, the laddertube comprising: an elongate tube made of a suitably rigid plastics material and adapted to be received in the raise, the tube having a series of steps moulded into an interior 25 side wall thereof so as to form a ladder extending substantially the full length of the tube; and, each step having a void provided there through to allow for drainage of fluid.

Preferably the void is provided adjacent an interior sidewall of the tube. Preferably the voids in each of the respective steps are aligned so as to form PCT/AU2014/000036 WO 2014/134656 5 an internal drainage channel through which fluids can flow straight down the interior sidewall of the tube behind the steps.

Preferably each of the steps has a hollow interior and is formed with a front wall defining an outer edge of the step, and a rear wall defining the void 5 through the hollow interior, the rear wall of the step providing additional strength and rigidity. Preferably the rear wall of each step is in the shape of an arc. Preferably an external sidewall of the tube is formed with a substantially flattened region extending the full length of the tube in the region of the void. Advantageously the flattened region creates an external drainage channel on 10 the footwall side of the laddertube, which allows water and other liquids to drain down the footwall side of the raise with minimum interference due to the presence of the laddertube.

Preferably the laddertube is one of a plurality of substantially identical laddertubes forming a modular system and the elongate tube is one of a 15 plurality of elongate tubes adapted to be joined end to end in the raise.

Throughout the specification, unless the context requires otherwise, the word “comprise” or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated integer or group of integers but 20 not the exclusion of any other integer or group of integers. Likewise the word “preferably" or variations such as “preferred”, will be understood to imply that a stated integer or group of integers is desirable but not essential to the working of the invention. Furthermore, throughout the specification, unless the context requires otherwise, the word “raise” will be understood to refer to any vertical 25 or angled underground development opening, bore or shaft that can be used for ventilation, materials handling or as a manway including, but not limited to, winzes and rises. WO 2014/134656 PCT/AU2014/000036 6

Brief Description of the Drawings

The nature of the invention will be better understood from the following detailed description of a preferred embodiment of the laddertube and modular system, given by way of example only, with reference to the accompanying 5 drawings, in which:

Figures 1 (a) and (b) are top perspective views of a first embodiment of the laddertube in accordance with the invention;

Figure 2 is a top plan view of the laddertube of Figure 1;

Figure 3 is an enlarged top plan view of the part of the circumference of 10 the laddertube of Figure 1 where the steps are located;

Figure 4 (a) is a side elevation of a pair of the laddertubes of Figure 1 joined end to end;

Figure 4 (b) is a cross-section view of the pair of laddertubes through the line A-A of Figure 4 (a); 15 Figure 5 is an enlargement of the join between the pair of laddertubes of Figure 4;

Figures 6 is an enlargement of a dog bracket provided on an external wall of the laddertube of Figure 1;

Figure 7 is a side elevation of the laddertube of Figure 1 viewed from 20 the footwall side; and,

Figure 8 illustrates the bulging in the cross-sectional area of the laddertube of Figure 1, compared to a prior art tube of circular cross-section. 25 PCT/AU2014/000036 WO 2014/134656 7

Detailed Description of Preferred Embodiments A first embodiment of a laddertube 10 in accordance with the invention, as illustrated in Figures 1 to 7, comprises an elongate tube 12 made of a suitably rigid plastics material and adapted to be received in a raise. The tube 12 has a 5 series of steps 14 moulded into an interior side wall of the tube 12 so as to form a ladder extending substantially the full length of the tube 12. In use, the tube 12 acts to protect a person on the ladder from falling rocks, and so on.

As can be seen most clearly in Figure 2, the elongate tube 12 is of generally circular cross-section and each step 14 is in the form of a generally planar 10 platform protruding inwardly from an interior side wall of the tube 12. Preferably an outer edge 16 of each step 14 is substantially straight and is formed on a chord of the cross-section of the tube 12. Preferably the outer edges 16 of all of the steps 14 are substantially vertically aligned.

Preferably the ladder of the laddertube 10 further comprises a pair of handrails 15 20 adapted to be attached ,to the steps 14. The handrails 20 extend substantially the full length of the tube 12. Typically each handrail 20 is in the form of a substantially rigid member of circular cross-section having an outside diameter that can be readily gripped by a person’s hand. The handrails 20 are preferably manufactured from a similar suitably rigid plastics 20 material as the tube 12.

As can be seen most clearly in Figures 1(b), 2 and 3, a plurality of the steps 14 are formed with a pair of enlarged side wings 18. The side wings 18 are each formed with a recess 22 for receiving the respective handrails 20 therein. In the illustrated embodiment the reCesses 22 are formed of semi-circular 25 cross-section with an inside diameter matching the outside diameter of the handrails 20. The handrails 20 are typically fastened in the recesses 22 by thermoplastic welding and/or a suitable plastics adhesive and/or other fasteners.

Preferably the laddertube 10 is one of a plurality of substantially identical 30 laddertubes 10 forming a modular system and the elongate tube 12 is one of a PCT/AU2014/000036 WO 2014/134656 8 plurality of elongate tubes 12 adapted to be joined end to end in the raise, as shown in Figure 4. A pair of the laddertubes 10 are typically joined end to end prior to installation in a raise. Then when the first pair has been installed, the next laddertube 10 is pushed down on top of the first pair, joined end to end, 5 and then used to push the first pair of laddertubes further down the raise. This process is continued until the full length of the raise has been covered.

As can be seen most clearly in Figures 1 and 4 (b), part only of the circumference of one end of the tubes 12 (in this embodiment the top end) is formed with an inside offset male edge 30 whereas the remainder of the one 10 end is formed with a non-offset male edge 32. Similarly, as can be seen most clearly in Figures 4 (b) and 5, part only of the circumference of the other end of the tubes 12 (in this embodiment the bottom end) is formed with an outside offset female edge 34 whereas the remainder of the bottom end is formed with a non-offset female edge 36. In use, when two tubes 12 of substantially 15 identical design are joined end to end, the inside offset male edge 30 on the top end of one tube 12a is received within the non-offset female edge 36 on the bottom end of the adjoining tube 12b, and the outside offset female edge 34 on the bottom end of the adjoining tube 12b is received around the nonoffset male edge 32 on the top end of the one tube 12a. 20 Preferably the inside offset male edge 30 is provided along the part of the circumference of the tube 12 corresponding substantially to the location of the series of steps 14 moulded into the side wall of the tube 12. The part of the side wall of the tube 12 in which the steps 14 are formed would normally rest against a footwall side of the raise. As can be seen most clearly in Figure 2, 25 this part of the circumference of the tube occupies about 40% of the circumference of the tube 12. In this part of the circumference of the joined tubes 12 the inside offset male edge 30 will protrude about 9mm from the internal wall of the tubes at the join (as can be seen in Figures 2 and 3). However this is not a problem in this region of the circumference as it will not 30 interfere with the free movement of personnel in the laddertube 10. PCT/AU2014/000036 WO 2014/134656 9

On the other hand, the outside offset female edge 34 is provided along the rest of the circumference of the tube 12. This part of the circumference of the tube 12 corresponds substantially to a hanging wall side of the tube. Although in this region of the circumference the offset female edge 34 will protrude 5 about 9mm from an external wall of the tubes 12 at the join (as can be seen in Figures 2, 4 and 5), advantageously the internal wall in this region of the circumference of the joined tubes is substantially smooth at the join (as can be seen most clearly in Figure 5). This is advantageous as it ensures a more comfortable climbing experience for personnel, since articles of clothing, 10 breathing apparatus or other equipment are less likely to catch on the internal wall of the laddertube 10. This feature also increases the internal space by at least 11mm at the join. It provides visual continuity in the ladderway when looking upwards.

The respective offset male and female edges 30 and 34 ensures that when 15 the laddertubes 10 are joined end-to-end, the tubes 12 are automatically aligned, and the steps 14 and handrails 20 of the adjoining tubes 12 will always align so as to form a continuous ladder throughout the length of the joined laddertubes 10. The amount of overlap of the tubes 12 at the joins can be reduced by about 15mm (from 90mm to 75mm), which will reduce material 20 usage by 350g/laddertube. Over the course of a year this could represent several thousand dollars of savings in material costs.

As noted above, and as shown most clearly in Figures 2 and 8, the elongate tube 12 is of generally circular cross-section, with an outer diameter of about 960mm. However typically the cross-section of the tube 12 bulges outwardly 25 on either side near the hanging wall side of the tube, i.e. along the remaining approximately 60% of the circumference of the tube where the outside offset female edge 34 is provided. This bulging or fully tangent non-rounded shape provides more internal space of about 31mm on each side of the centre line. This provides a more comfortable climbing position for users carrying a 30 breathing apparatus and for climbers in low angle rises. The illustrated embodiment of the laddertube 10 is designed for installation in a raise having PCT/AU2014/000036 WO 2014/134656 10 a minimum diameter of 1066mm, as shown in Figure 2. This allows a sufficient gap to enable installation, and to accommodate a dog bracket 40 on the external wall of the tube 12. The dog bracket 40 is conveniently built-into the moulding for the tube 12 on the hanging wall side, and is used as a lifting lug. 5 Previously it was necessary to bolt a plate to the tube as a lifting lug.

Each tube 12 of the illustrated embodiment is approximately 2.175 metres in length and is joined to an adjoining tube 12 by welding or bolting. Typically there are seven steps 14 moulded into the interior side wall of each tube 12. Preferably three of the steps 14, spaced apart at equal intervals, are formed 10 with the side wings 18. This spacing ensures that the handrails 20 have sufficient support to be mounted securely in the tube 12, whilst allowing a user to maintain his or her grip on the handrails while climbing without having to release the handrails completely at every step in order move the hands along the handrails. 15 Advantageously each step 14 has a void 50 provided there through to allow for drainage of fluid. Preferably the void 50 is provided adjacent an internal sidewall of the tube corresponding to the footwall side of the raise. Preferably the voids 50 in each sfep are aligned so as to form an internal drainage channel through which fluids can flow straight down the internal sidewall of the 20 tube behind the steps 14. Preferably each of the steps 14 has a hollow interior and is formed with a front wall 52 defining the outer edge 16 of the step and a rear wall 54, as can be seen most clearly in Figure 4 (b) and 5. The rear wall 54 defines the void 50 through the hollow interior of the step 14. This rear wall 54 provides additional strength and rigidity for each of the steps 14. Preferably 25 the rear wall 54 is in the shape of an arc.

The provision of an internal drainage channel is very important as it ensures the accumulation of fluids within the laddertubes 10 can be minimised. Puddles of water on the steps 14 are potentially hazardous, resulting in slipping and loss of footing, as well as spattering of climbers lower on the 30 ladderway. Preferably the outer edge 16 of each step14 is provided with a tread grip 24, as shown in Figures 2 and 3. 11

As can be seen most clearly in Figures 1 (a), 3, 7 and 8, the external sidewall of the tube 12, in the region of the void 50, has a substantially flattened region 60 so as to also create an external drainage channel on the footwall side of the laddertube 10. This allows water and other liquids to drain down the 5 footwall side of the raise with minimum interference due to the presence of the laddertube.

The tubes 12 of the laddertube 10, with the steps moulded integral therewith, can be readily mass-produced by a suitable plastics moulding process such as, for example, rotamoulding. 10 Now that a preferred embodiment of the laddertube has been described in detail, it will be apparent that it provides a number of advantages over the prior art, including the following: (i) Due to its unitary construction it is much easier to manufacture and install than prior art systems. 15 20 25 WO 2014/134656 PCT/AU2014/000036 (ii) Male and female mating edges on the ends of adjoining tubes ensures they are automatically aligned, and therefore the steps and handrails of the adjoining tubes will always align so as to form a continuous ladder throughout the length of the joined laddertubes. (iii) Due to its relatively lightweight construction it is easier to transport and handle. (iv) Due to its modular construction it can be used to provide any desired length of ladderway. Longer lengths, in particular, are simpler and easier to install. (v) Because the system is manufactured substantially entirely of plastics materials it will not corrode like prior art steel ladderways. PCT/AU2014/000036 WO 2014/134656 12 (vi) The tube of the laddertube provides improved safety and comfort for personnel and also protects the ladder from groundwater and seepage. 5 10 15 (vii) It is relatively inexpensive to manufacture and can be assembled and installed without the need for expensive steel welding equipment or a large crane. (viii) The moulding of the steps to the interior of the tube prevents the potential safety issue of the ladder coming away from the tube when the ladder is provided as a separate component which is affixed to the tube. (ix) Non-circular cross-section of the tube provides increased internal space for movement of personnel climbing through the laddertube, as well as providing an external drainage channel. (x) Improved step design provides for increased strength and an internal drainage channel.

It will be readily apparent to persons skilled in the relevant arts that various modifications and improvements may be made to the foregoing embodiments, in addition to those already described, without departing from the basic inventive concepts of the present invention. For example, the shape and 20 - configuration of the tube and the steps may vary considerably from that shown in the accompanying drawings. For instance, although the arcuate shape of the void in the steps, is preferred because of its inherent strength and ease of moulding, the void could be made of rectangular cross-section. Therefore, it will be appreciated that the scope of the invention is not limited to the specific 25 embodiments described but is to be determined from the appended claims.

Claims

Claims

1. A laddertube for an underground raise, the laddertube comprising: an elongate tube made of a suitably rigid plastics material and adapted to be received in the raise; the tube having a series of steps moulded into an interior side wall thereof so as to form a ladder extending substantially the full length of the tube; and part only of the circumference of one end of the tube is formed with an inside offset male edge whereas the remainder of the one end is formed with a non-offset male edge, and part only of the circumference of the other end of the tube is formed with an outside offset female edge whereas the remainder of the other end is formed with a non-offset female edge wherein, in use, the inside offset male edge can be received within the non-offset female edge on the other end of an adjoining tube of identical design and the outside offset female edge can be received around the non-offset male edge on the one end of the adjoining tube when the tubes are joined end to end.
2. A laddertube as defined in claim 1, wherein the inside offset male edge is provided along the part of the circumference of the tube corresponding substantially to the location of the series of steps moulded into the side wall of the tube.
3. A laddertube as defined in claim 2, wherein the outside offset female edge is provided along the part of the circumference of the tube corresponding substantially to a hanging wall side of the tube wherein, in use, the internal wall of the hanging wall side of adjoining tubes is substantially smooth in the region of the join when the tubes are joined end to end.
4. A laddertube as defined in claim 3, wherein the tube is of generally circular cross-section and each step is in the form of a generally planar platform protruding inwards from the interior side wall of the tube and wherein, in use, the part of the side wall of the tube in which the steps are formed normally rests against a footwall side of the raise.
5. A laddertube as defined in claim 4, wherein the generally circular crosssection of the tube bulges outwardly on either side near the hanging wall side of the tube.
6. A laddertube as defined in claim 5, wherein an outer edge of each step is substantially straight and is formed on a chord of the cross-section of the tube near the footwall side of the tube.
7. A laddertube as defined in claim 6, wherein the outer edge of each step is provided with a tread grip.
8. A laddertube as defined in any one of the preceding claims, wherein the laddertube further comprises a pair of elongate handrails adapted to be attached to the steps and extending substantially the full length of the tube; and, wherein a plurality of the steps are formed with a pair of enlarged side wings, the side wings each formed with a recess for receiving the respective handrails therein.
9. A laddertube as defined in claim 8, wherein the pair of enlarged side wings is provided on selected steps only with one or more steps absent the enlarged side wings provided there between.
10. A laddertube as defined in claim 9, wherein each handrail is in the form of a substantially rigid member of circular cross-section having an outside diameter that can be readily gripped by a person’s hand.
11. A laddertube as defined in claim 10, wherein the handrails are manufactured from a similar suitably rigid plastics material as the tube.
12. A laddertube as defined in claim 11, wherein each handrail is formed with a protruding portion of reduced diameter at a top end, which is adapted to be received in a matching recess provided in a bottom end of a corresponding handrail on an adjacent tube.
13. A laddertube as defined in claim 1, wherein each step is provided with a void therethrough to allow for drainage of fluid.
14. A laddertube as defined in claim 13, wherein the void is provided adjacent an interior sidewall of the tube.
15. A laddertube as defined in claim 14, wherein the voids in each of the respective steps are aligned so as to form an internal drainage channel through which fluids can flow straight down the interior sidewall of the tube behind the steps.
16. A laddertube as defined in claim 15, wherein each of the steps has a hollow interior and is formed with a front wall defining an edge of the step and a rear wall defining the void through the hollow interior, the rear wall of the step providing additional strength and rigidity.
17. A laddertube as defined in claim 16, wherein the rear wall of each step is in the shape of an arc.
18. A laddertube as defined in any one of claims 13 to 17, wherein an external sidewall of the tube in the region of the void is formed with a substantially flattened region extending the full length of the tube.
19. A laddertube as defined in claim 18, wherein the flattened region creates an external drainage channel on the footwall side of the laddertube, which allows water and other liquids to drain down the footwall side of the raise with minimum interference due to the presence of the laddertube.
20. A laddertube as defined in any one of the preceding claims, wherein the laddertube is one of a plurality of substantially identical laddertubes forming a modular system and the elongate tube is one of a plurality of elongate tubes adapted to be joined end to end in the raise.