AU2020102598A4 - Improved Portable Ladder Configuration - Google Patents
Improved Portable Ladder Configuration Download PDFInfo
- Publication number
- AU2020102598A4 AU2020102598A4 AU2020102598A AU2020102598A AU2020102598A4 AU 2020102598 A4 AU2020102598 A4 AU 2020102598A4 AU 2020102598 A AU2020102598 A AU 2020102598A AU 2020102598 A AU2020102598 A AU 2020102598A AU 2020102598 A4 AU2020102598 A4 AU 2020102598A4
- Authority
- AU
- Australia
- Prior art keywords
- leg
- stile
- strut
- ladder
- foot
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 230000007246 mechanism Effects 0.000 claims abstract description 40
- 230000005484 gravity Effects 0.000 claims description 7
- 238000000034 method Methods 0.000 claims description 7
- 238000003780 insertion Methods 0.000 description 3
- 230000037431 insertion Effects 0.000 description 3
- 238000010276 construction Methods 0.000 description 2
- 208000025940 Back injury Diseases 0.000 description 1
- 229920002943 EPDM rubber Polymers 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000012856 packing Methods 0.000 description 1
- 239000012858 resilient material Substances 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E06—DOORS, WINDOWS, SHUTTERS, OR ROLLER BLINDS IN GENERAL; LADDERS
- E06C—LADDERS
- E06C7/00—Component parts, supporting parts, or accessories
- E06C7/42—Ladder feet; Supports therefor
- E06C7/44—Means for mounting ladders on uneven ground
-
- E—FIXED CONSTRUCTIONS
- E06—DOORS, WINDOWS, SHUTTERS, OR ROLLER BLINDS IN GENERAL; LADDERS
- E06C—LADDERS
- E06C1/00—Ladders in general
- E06C1/02—Ladders in general with rigid longitudinal member or members
- E06C1/04—Ladders for resting against objects, e.g. walls poles, trees
- E06C1/06—Ladders for resting against objects, e.g. walls poles, trees in one piece
-
- E—FIXED CONSTRUCTIONS
- E06—DOORS, WINDOWS, SHUTTERS, OR ROLLER BLINDS IN GENERAL; LADDERS
- E06C—LADDERS
- E06C7/00—Component parts, supporting parts, or accessories
- E06C7/42—Ladder feet; Supports therefor
- E06C7/423—Ladder stabilising struts
-
- E—FIXED CONSTRUCTIONS
- E06—DOORS, WINDOWS, SHUTTERS, OR ROLLER BLINDS IN GENERAL; LADDERS
- E06C—LADDERS
- E06C7/00—Component parts, supporting parts, or accessories
- E06C7/42—Ladder feet; Supports therefor
- E06C7/426—Height adjustable supports for receiving both ladder feet
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Ladders (AREA)
Abstract
A ladder 1 including rungs 2, a first stile 3a, a second stile 3b, a first leg 4a, a second
leg 4b, a first foot 6a, a second foot 6b, a first strut 8a, a second strut 8b and two or
more locking mechanisms 9a, 9b. The first leg is pivotally connected to the first stile
and the second leg is pivotally connected to the second stile to enable the legs to be
mutually splayed. The one or more locking mechanisms are configured to lock the first
leg and second leg at orientations selected to suit uneven ground and at which the first
leg and the second leg hold the first stile and the second stile off the ground.
DRAWINGS
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Description
992
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Fiig 2
[0001]The invention relates to portable ladders.
[0002] A simple form of portable ladder includes a pair of parallel stiles mutually connected by rungs. The lower ends of the stiles rest on the ground whilst the upper ends are rested against the wall that is to be scaled.
[0003] Rungs are sometimes referred to as 'treads'. Stiles are sometimes referred to as 'rails'.
[0004] Portable ladders can be dangerous, in part because they are at risk of toppling to one side or the other.
[0005] One approach to addressing this risk is to incorporate downwardly-splayed stiles to provide a wider base of support to the ladder. In the context of larger ladders, the lower ends of the stiles can be 1200 mm (4 ft) apart. The weight and bulk of such ladders can be inconvenient and present their own safety risks.
[0006] Some ladders incorporate screw-adjustable leg levellers which in theory enable the rungs to be levelled. In reality, although such screw adjustments may reduce the safety risk associated with using a ladder on uneven ground, the risk of toppling arising from the inherent slender shape of the simple form of ladder is not addressed.
[0007] Another arrangement incorporates a respective pivotally-mounted strut for each of the stiles. The struts are arranged to be outwardly splayed and placed on the adjacent ground to provide a wider base for support. The present inventor has recognised that, in practice, these ladder arrangements too are often installed with unsatisfactory packing arrangements.
[0008] A fourth approach to reducing the risk of toppling incorporates a respective pivotally-mounted leg for each of the stiles. The legs are arranged to be outwardly splayed at various orientations to allow for level treads on uneven ground and a wider base for support generally. The present inventor has recognised that, in practice, these ladders can be cumbersome or awkward to adjust, especially for the time-poor worker and for those who might be susceptible to back injuries.
[0009] Beyond the simple ladder mentioned above, similar issues arise in relation to other ladders such as extension ladders and A-frame ladders.
[0010] Accordingly, the present invention aims to provide improvements in and for portable ladders suited to flat or uneven ground, or at least to provide an alternative for those concerned with portable ladders.
[0011] One aspect of the invention provides a ladder including
a first stile;
a second stile;
rungs connecting the first stile to the second stile;
a first leg;
a second leg;
a first foot;
a second foot; a first strut; a second strut; and two or more locking mechanisms; the first end of the first leg being pivotally connected to the first stile below the lowest of rungs ; the second end of the first leg being connected to the first foot; the first end of the first strut being pivotally connected to the top side of the first leg at a point that is less than 200mm from the centre of gravity of the first foot; the second end of the first strut being pivotally connected to the first locking mechanism; the first locking mechanism being connected to the first stile at a point that is higher than the second lowest rung; and the two or more locking mechanisms being configured to lock the first leg and second leg at orientations selected to suit uneven ground and at which the first leg and the second leg hold the first stile and the second stile off the ground.
[0012] Each of the struts is a position-adjustable strut.
[0013] Preferably, each of the two or more locking mechanisms include one or more sliding blocks, pivotally mounted to the second end of the respective strut for insertion into one or more guide brackets mounted on the respective stile. Most preferably, each of the locking mechanisms includes a spring-loaded shear pin mounted to the strut for easy insertion and withdrawal to a selected index hole on the respective stile.
[0014] Each of the stiles includes a series of index holes, sized and aligned to enable easy insertion and withdrawal of the index pin, as mounted to the respective strut, for the purpose of locking the first leg and second leg at orientations selected to suit uneven ground.
[0015] Each of the guide brackets includes one or more stop bolts to prevent the mounted slide blocks from sliding beyond the length of the guide rails in either the up or down direction.
[0016] The ladder may include an orientation-indicating device. The orientation indicating device may include an observable bubble.
[0017] Optionally, the first leg and the second leg each have a respective foot formed of durable material; shaped to grip the ground at a range of leg orientations and ladder inclinations.
[0018] The ladder may be a simple ladder or a trestle-type ladder, or it may be an A-frame ladder including a third stile and a fourth stile. The ladder may be an extension ladder. Other variants may take the form of a simple 'single' type ladder consisting of a single section. Alternatively the ladder may have separable sections, e.g. two or three separable sections, that can be temporarily 'locked' together, e.g. locked with plates and lock pins, when in use and separated for transport/storage.
[0019] Optionally, the ladder may be an existing portable ladder, comprising
a first existing stile;
a second existing stile;
existing rungs connecting the first existing stile to the second existing stile and subsequently fitted with
a first leg; a second leg; a first foot; a second foot; a first strut; a second strut; and two or more locking mechanisms; the first end of the first leg being pivotally connected to the first existing stile below the lowest of existing rungs ; the second end of the first leg being connected to the first foot; the first end of the first strut being pivotally connected to the top side of the first leg at a point that is less than 200mm from the centre of gravity of the first foot; the second end of the first strut being pivotally connected to the first locking mechanism; the first locking mechanism being connected to the first existing stile at a point that is higher than the second lowest existing rung; and the two or more locking mechanisms being configured to lock the first leg and second leg at orientations selected to suit uneven ground and at which the first leg and the second leg hold the first existing stile and the second existing stile off the ground.
[0020] Another aspect of the invention provides a method of configuring a ladder to suit uneven ground;
the ladder including a first stile; a second stile; rungs connecting the first stile to the second stile; a first leg; a second leg; a first foot; a second foot; a first strut; a second strut; and two or more locking mechanisms; the first end of the first leg being pivotally connected to the first stile below the lowest of rungs ; the second end of the first leg being connected to the first foot; the first end of the first strut being pivotally connected to the top side of the first leg at a point that is less than 200mm from the centre of gravity of the first foot; the second end of the first strut being pivotally connected to the first locking mechanism; the first locking mechanism being connected to the first stile at a point that is higher than the second lowest rung; the method including pivoting the first leg and second leg to selected orientations to suit the uneven ground and at which the first leg and the second leg hold the first stile and the second stile off the ground; and configuring the two or more locking mechanisms to lock the first leg and second leg to selected orientations.
[0021] Features of any of the embodiments described herein may be combined with features of other embodiments without limitation.
[0022] Figure 1 is a front view of a lower end of a ladder with position-adjustable struts in a first configuration;
[0023] Figure 2 is a front view of a lower end of a ladder with position-adjustable struts in a second configuration;
[0024] Figure 3 is a front view of the lower end of the ladder with position adjustable struts in a third configuration;
[0025] Figure 4 is a front view of the locking mechanism;
[0026] Figure 5 is a side view of the locking mechanism;
[0027] Figure 6 is a cross-section view corresponding to the line A-A in Figure 4;
[0028] Figure 7 is a top view of a foot;
[0029] Figure 8 is a side view of the foot; and
[0030] Figure 9 is a cross-section view corresponding to the line B-B in Figure 8.
[0031] Figures 1, 2 and 3 illustrate variations of a ladder 1 incorporating stiles 3a, 3b mutually connected by rungs 2. Legs 4a, 4b are pivotally connected to the stiles 3a, 3b at pivotal connections 5a, 5b.
[0032] Legs 4a, 4b are pivotally connected to struts 8a, 8b at a point that is less than 200mm from the centre of gravity of the foot 6a, 6b at pivotal connections 7a, 7b.
[0033] Legs 4a, 4b are locked at selected orientations by a locking mechanism 9a (Figures 4, 5 and 6), 9b. The mechanisms 9a, 9b are independently unlockable to enable the legs 4a, 4b to be pivoted to selected orientations. In Figures 1 and 2, the legs are widely splayed to provide a wider base of support. In Figure 3, the legs are substantially parallel to their respective stiles to provide a base of support akin to a simple ladder. This is a compact configuration enabling the ladder to be stored as efficiently as a simple ladder of similar size.
[0034] Preferably the rungs 2 are mutually spaced by a common nominal spacing and the ladder is configured so that, when the legs are splayed to their widest configuration and the ladder is on level ground, a lowest of the rungs is at the nominal spacing above the ground.
[0035] In Figure 2, the leg 4b is substantially parallel to its stile 3b whilst the leg 4a is outwardly splayed to level the rungs 2 whilst the ladder sits atop uneven ground UG. In this configuration it is safest for workers to step towards the left-hand side of the treads so as to place their centres of mass between the feet 6a, 6b. The ladder may carry instructions to this effect. As such a preferred method of using a ladder, having a foot movable relative to a stile, is disclosed.
[0036] Struts 8a, 8b (Figures 1, 2 and 3) may carry instructions to reduce the risk of workers tripping on the feet 6a, 6b.
[0037] A preferred construction of struts 8a, 8b entails a tubular construction to reduce the risk of strut buckling failure under extra-ordinary loading conditions. In Figures 1, 2 and 3, each of the struts 8a, 8b is pivotally connected to the locking mechanisms 9a, 9b.
[0038] Various locking arrangements are contemplated. By way of example, each of the pivotal connections 5a, 5b may have its own locking mechanism such as a detent arrangement that enables each leg to click into place at selected angular orientations relative to its stile.
[0039] A preferred locking mechanism 9a, 9b entails one or more guide rails 10a, 1Ob (Figures 4, 5 and 6) attached to each respective stile 3a, 3b with suitable fasteners 12, at points above the second lowest tread. A most preferred connection position is above the fourth lowest tread.
[0040] In Figure 6, one or more sliding blocks 15a, 15b are pivotally mounted to each respective strut 8a, 8b using a dowel pin 17a. The sliding blocks 15a, 15b are able to slide freely inside the guide rails 10a, 1Ob. Fasteners 12 ensure the sliding blocks 15a, 16a are unable to be separated from the guide rails 10a, 1Ob.
[0041] A most preferred locking mechanism 9a, 9b includes a spring-loaded shear pin 14a. The shear pin 14a is mounted inside a mount block 16a fixed to the respective strut 8a and configured to allow the worker to pull back the pin and select the required index hole 13a (Figure 4) for the pin to be re-inserted, thereby locking the strut, 8a in a fixed position.
[0042] The use of position-adjustable struts has been found to be simple and convenient, and particularly suited to reducing physical effort, such as bending up and down, as normally required to adjust ladders for different ground conditions and locations.
[0043] A preferred method of setting up the ladder correctly entails up-righting the ladder into the approximate required position and inspecting the rungs to provide an indication of the direction in which adjustment is required.
[0044] If the alignment of the treads 2 are not level, the appropriate one of the two locking mechanisms, 9a, 9b can be unlocked, adjusted and relocked to pivot the legs 4a, 4b towards positions selected to suit the uneven ground, UG. By way of example, with reference to Figure 2, if observation of the treads indicated that anti-clockwise rotation of the ladder was required, the locking mechanism 9a could be adjusted, enabling foot 6a to raise vertically by an appropriate amount so that the treads 2 are observed to be horizontal.
[0045] During the tread-levelling process, the stiles 3a, 3b are held off the ground UG and the ladder is equally supported by the legs 4a, 4b. The struts 8a, 8b are pivotally connected to the legs 4a, 4b. As such, the ladder is solidly supported by two points of contact, i.e. the feet 6a, 6b, both or all of which bear significant weight. The present inventor has recognised that this is a significant advance over the previously mentioned pre-existing pivotally mounted leg arrangements ([007]) in which, for the example of a simple ladder, there are four points of contact, two of which may not be solidly engaged with the ground at any one time. This can cause packers to move the ladder to'walk'as a workman shifts their weight around on the ladder.
[0046] For improved engagement with the ground, each leg 4a, 4b has a respective foot 6a, 6b as detailed in Figures 7 to 9. Each foot 6 at least predominantly consists of an integral body of suitable resilient material, e.g. EPDM rubber. In this case, the foot 6a is a cap fitted to the end of the main body of the leg 4a.
[0047] As seen from above (Figure 7), the foot 6 has a socket 18 shaped to receive the I-beam shaped leg 4a. As shown in Figures 8 and 9, the lower ground engaging portion of the foot 6a is curved 19, 20 in at least two orthogonal directions. The curve 19 (Figure 8) is configured to engage the ground whether the foot 6 is vertical or inclined at a suitable angle, in this case 17.5 degrees, to engage the ground when the ladder is tilted, e.g. tilted up against a wall. Concurrently, the curve 20 (Figure 9) is configured to engage the ground whether the legs 4a, 4b are rotated outwards or vertically aligned with their respective stiles 3a, 3b. This provides the worker with the ability to set up the ladder on many different types of uneven grounds.
[0048] Figure 9 illustrates a cross-section view corresponding to line B-B in Figure 8. In this example, the foot 6a has an ellipsoid exterior 19 and a circular exterior in an orthogonal direction, although other rounded profiles are possible.
[0049] Preferred forms of the ladder 1 have three or more rungs. One variant of the disclosed ladder is an A-frame ladder having a similar arrangement of legs 4a, 4b and locking mechanism 9a, 9b at each of the front and the back sections of the A-frame.
[0050] The invention is not limited to the described examples. Rather, the invention is defined by the claims.
Claims (5)
1. A ladder including
a first stile;
a second stile;
rungs connecting the first stile to the second stile;
a first leg;
a second leg;
a first foot;
a second foot;
a first strut;
a second strut; and
two or more locking mechanisms;
the first end of the first leg being pivotally connected to the first stile below the lowest of rungs;
the second end of the first leg being connected to the first foot;
the first end of the first strut being pivotally connected to the top side of the first leg at a point that is less than 200mm from the centre of gravity of the first foot;
the second end of the first strut being pivotally connected to the first locking mechanism; the first locking mechanism being connected to the first stile at a point that is higher than the second lowest rung; and the two or more locking mechanisms being configured to lock the first leg and second leg at orientations selected to suit uneven ground and at which the first leg and the second leg hold the first stile and the second stile off the ground.
2. The ladder of claim 1 wherein each of the two or more locking mechanisms include one or more sliding blocks, pivotally mounted to the second end of the respective strut; and
one or more guide brackets mounted on the respective stile; and
a spring-loaded shear pin mounted to the second end of the strut; and the shear pin being configured to insert into, and withdraw from, a selected index hole on the respective stile.
3. A set of ladder components including
a first leg;
a second leg;
a first foot;
a second foot;
a first strut;
a second strut; and
one or more locking mechanisms;
the first end of the first leg being pivotally connected to a first existing ladder stile below the lowest of existing rungs ; the second end of the first leg being connected to the first foot; the first end of the first strut being pivotally connected to the top side of the first leg at a point that is less than 200mm from the centre of gravity of the first foot; the second end of the first strut being pivotally connected to the first locking mechanism; the first locking mechanism being connected to a first existing ladder stile at a point that is higher than a second lowest existing rung; and the two or more locking mechanisms being configured to lock the first leg and second leg at orientations selected to suit uneven ground and at which the first leg and the second leg hold the first existing stile and the second existing stile off the ground.
4. The ladder of any one of claims 1 to 3 being a trestle-type ladder.
5. A method of configuring a ladder to suit uneven ground;
the ladder including
a first stile;
a second stile;
rungs connecting the first stile to the second stile;
a first leg;
a second leg;
a first foot;
a second foot; a first strut; a second strut; and two or more locking mechanisms; the first end of the first leg being pivotally connected to the first stile below the lowest of rungs ; the second end of the first leg being connected to the first foot; the first end of the first strut being pivotally connected to the top side of the first leg at a point that is less than 200mm from the centre of gravity of the first foot; the second end of the first strut being pivotally connected to the first locking mechanism; the first locking mechanism being connected to the first stile at a point that is higher than the second lowest rung; the method including pivoting the first leg and second leg to selected orientations to suit the uneven ground and at which the first leg and the second leg hold the first stile and the second stile off the ground; and configuring the two or more locking mechanisms to lock the first leg and second leg to selected orientations.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU2019903938 | 2019-10-18 | ||
| AU2019903938A AU2019903938A0 (en) | 2019-10-18 | Improved Portable Ladder | |
| AU2020903567 | 2020-10-02 | ||
| AU2020903567A AU2020903567A0 (en) | 2020-10-02 | Improved Portable Ladder Configuration |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| AU2020102598A4 true AU2020102598A4 (en) | 2020-11-26 |
Family
ID=73458031
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| AU2020102598A Active AU2020102598A4 (en) | 2019-10-18 | 2020-10-05 | Improved Portable Ladder Configuration |
Country Status (1)
| Country | Link |
|---|---|
| AU (1) | AU2020102598A4 (en) |
-
2020
- 2020-10-05 AU AU2020102598A patent/AU2020102598A4/en active Active
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FGI | Letters patent sealed or granted (innovation patent) |