AU2006210078A1

AU2006210078A1 - Collapsible combination ladder

Info

Publication number: AU2006210078A1
Application number: AU2006210078A
Authority: AU
Inventors: Per-Olof Eriksson
Original assignee: Telesteps AB
Current assignee: Telesteps AB
Priority date: 2005-02-01
Filing date: 2006-02-01
Publication date: 2006-08-10
Also published as: JP2008528834A; CA2594804A1; EP1686233A1; NO20074352L; CN101111658A; WO2006082032A1; NZ556606A; EA012890B1; EA200701641A1

Description

WO 2006/082032 PCT/EP2006/000856 COLLAPSIBLE COMBINATION LADDER Field of the invention The present invention relates to a collapsible stepladder provided with ladder sections being 5 telescopically inserted in each other. Background of the invention Collapsible and expandable stepladders are known in the art. Below examples of prior art are stepladders described. 10 In WO-Al-99/51848 a telescopically collapsible stepladder is disclosed comprising two legs that are hinged to one another. Each leg is formed'of telescopically collapsible sections having latch medhanisms in each of the rungs for automatically looking the sections relative to 15 one another when the leg i's extended. The latch mechanisms in each rung are designed -to-release the next higher section when the rung is collapsed against the next lower rung. The separation of the rungs of one of the legs, when ,the stepladder is extended, is greater than the separation 20 of the rungs in the other leg. The problem with the stepladder of WO-Al-99/51848 is that the collapsible sections of the two legs have different height, which is why the stepladder will never pass type approval. Further, the stepladder can not be converted to a straight ladder, 25 since folding the two legs to be adjacent, results in a ladder with many small steps due to the different height of collapsible sections. In US-A-4 989 692 a ladder including two hinged sections is disclosed, that can be oriented in an inverted 30 V-configuration for use as a stepladder, or in a straight linear configuration for use as a straight ladder. Each section of the ladder includes a number of U-shaped support units, each of which defines a crossbar and two downwardly extending side rails. The side rails of the different U- WO 2006/082032 PCT/EP2006/000856 2 shaped units are of graduated cross sectional dimensions, so that the units can be contracted together by telescopically sliding the aligned side rails within one another. The problem with the ladder of US-A-4 989 692 is 5 that.the two sections of the ladder can not be used without an external support or the user will need to balance while working, which is not preferable from a work safety aspect. ,This is due to the lack of support provided on the ladder while'using the upper ladder sections of the ladder. 10 Another problem with the ladder is that if the'ladder is Converted to a straight ladder, the ladder is rather unstable since the two legs are folded up -and fixed to each >other by a swingable tie bar 26. Such a f thing arrangement s neither very secure, nor is it very stable and would not 15 pass type approval. In GB-A-2 110 286 another stepladder is disclosed, inclidirtg a first set of strong and telescopic elements, a second set of parts, each comprising a support surface forming one step of the ladder. Each part is transversely 20 connected to one element or group of strong elements of the first set. A set of stopper studs and locking means between the various strong elements of the first set is arranged to ensure at least the stability of the two extreme positions of the ladder, that is, of the ladder folded up on itself 25 and of the extended ladder. The ladder of GB-A-2 110 286 not only suffers from the same problems as US-A-4 989 692, but also lacks a locking or fixing arrangement in the converted disposition. The object of the present invention is to overcome 30 the disadvantages and problems with the prior art step ladders and to provide a stepladder, which is easy and safe to handle and which is possible to convert into a straight ladder without lowering the standards of safety and manageability.

WO 2006/082032 PCT/EP2006/000856 3 Summary of the invention A stepladder according to the characterizing features of claim 1 solves the above problem. The features of the dependent claims define further 5 aspects of the claimed invention and preferred embodiments. Brief description of the drawings In the.following, the invention will be explained. with reference to the accompanying drawings, wherein: Fig. 1 is a perspective view of a maximally collapsed 10 stepladder according to the invention; Fig. 2 is a perspective view of the stepladder according to the invention, where all ladder sections are fully 'extended; Fig. 3 is a. side view of the stepladder accordi-ng to 15 the invention,- where all ladder sections are fully extended; Fig. 4 is a perspective view of the ladder according to the invention in a converted style as a straight ladder having one ladder section collapsed; 20 Fig. 5 is a side view of the ladder according to the invention in a converted style as a straight ladder having one ladder section collapsed; Fig. 6 is a side view of the stepladder according to the invention provided with a locking device, where all 25 ladder sections are fully extended; and Figs. 7-8 are side views of the stepladder according to the invention provided with a locking device, where all ladder sections are completely collapsed. Detailed description of the embodiments 30 A collapsible stepladder 1 according to the invention is shown in the drawings. Fig. 1 shows a collapsible stepladder 1 comprising a first ladder leg 2, which is hingedly connected to a second ladder leg 3 in the upper ends of the first and second ladder leg 2, 3 by a hinge WO 2006/082032 PCT/EP2006/000856 4 connection 5. Each of the ladder legs 2, 3 comprise several ladder sections 4a-4d, where each ladder section 4a-4d comprises two ladder bars 6, 7, arranged parallel to each other and interconnected at one end by a rung 8 to form a 5 U-shaped ladder section 4a-4d. The ladder sections 4a-4d are telescopically inserted into a lower ladder section to form a collapsible ladder leg 2, 3. The ladder legs 2, 3 further comprise a lower ladder section 4e, which comprises two ladder bars 6, 7, arranged parallel to each other and 10 interconnected at a upper end-by a rung 9, at a lower end by a ladder base 10 and in between the rung 9 and the ladder base 10 by another rung 11. The ladder sections 4a 4d are telescopically inserted into the ladder section 4e. The ladder legs 2,3 .hould comprise at least three 15 ladder sections 4a-4e, but iha preferred embodiment four collapsible ladder sections 4a-4d are arranged together with the lower ladder section 4e. The number of ladder sections is limited by the stability of the stepladder and the requirement to pass type approval. 20 Each rung 8, 9 comprises a retaining mechanism for automatically locking the ladder sections relative to one another when the ladder legs 2,3 are extended. The retaining mechanism could be any kind previously known in the art, e.g. any of the retaining mechanisms shown in EP 25 B1-0 527 766 or EP-Al-l 402 143. The second. ladder leg 3 is provided with a support part 12 in one end. The support part 12 is telescopically extendible from the second ladder leg 3 to form a ladder extension 12 of the ladder leg 3, and the support part 12 30 projects above the hinge connection 5 between the two ladder legs 2, 3. The support part 12 comprise at least one support section 12a-12b, each support section comprising two ladder bars 6, 7 arranged parallel to each other and interconnected at one end by a rung 16 to form at least one 35 U-shaped support section 12a-12b. The support sections 12a- WO 2006/082032 PCT/EP2006/000856 5 12b are telescopically inserted into the ladder leg 3 to form a collapsible support part 12. The support part 12 also comprises an upper support section 12c, comprising two ladder bars 6, 7, arranged parallel to each other and 5 interconnected at one end by a rung 13 to form a U-shaped support section 12c. The support section 12c is te-lescopically inserted into the lower support section 12a 12b. In Fig 2. the ladder is shown, having both ladder 10 'legs 2, 3 and the support or extension part 12,.fully extended. The support part 12 enables the user of the stepladder to stand on the upper ladder section 4a-4b as the- support part 12 makes the user feelisafe.- In Fig. 2 the support part 12 comprises two collapsible ladder sections 15 12-a and 12c. On the upper rung 13 of the support part 12, a device for holding tools or objects, such an a tray, a table, a shelf, a box/case or a basket, can be arranged. The device is clamped, squeezed, hanged, hooked or in any other suitable manner arranged to be positioned at the 20 upper rung 13. The rung 13 might be arranged with receiving means such as holes, chamfered surfaces, recesses or the like to better receive the holding device. In Fig. 2 a strap 14 is also shown arranged between the ladder legs 2, 3 to increase the stability of the 25 ladder in the extended and folded mode and to prevent the ladder legs from splaying apart. The strap 14 is attached by suit fastening means, e.g. a pop rivet or the like, in one end to a rear side of a rung 8 of the ladder leg 2 and in another end to a rear side of a rung 8 of the ladder leg 30 3. Preferably, the strap 14 is attached to the rungs 8 positioned on ladder section 4e of the ladder legs 2, 3, respectively, but it would also be possible to attach the strap 14 to rungs associated with ladder sections located above or below ladder sections 4e. The strap 14 is also 35 shown in Figs. 3 and 5, but has been omitted in Figs. 1 and WO 2006/082032 PCT/EP2006/000856 6 4 for clarity reasons. The strap 14 can be made of nylon woven nylon material. In Fig. 3 is shown how the hinge connection 5 almost creates a platform between the upper part of the ladder 5 legs 2, 3, that can be used for placing a toolbox or the like or to stand on. In Figs. 4 and 5 the ladder section 4d of the ladder leg 2 is collapsed. The stepladder 1 is converted to. a straight ladder, which is positioned against a wall. The 10 support part 12 enables the ladder to be leaned against the. wall without the ladder leg 2 interfering or instabilizing the ladder in the leaned position. Since the ladder <section. 4d of the, ladder leg 2 is collapsed, the ladder leg .2 is. hanging freely and out of the way when the ladder isi 15 convertedto a straight ladder. Any or several:of.the collapsible ladder sections 4a-4d can be collapseds.To ensure that the collapsed ladder sections are not extended by its own weight, a holding means 15 holds the collapsed ladder sections and the ladder section positioned 20 adjacently below the collapsed ladder sections together. In Fig. 4 the holding means is a strap 15 of a nylon material, but it can also be a hook, which is attached to the rung of one ladder section and which can be pivoted so that the hook part is surrounds the rung of an adjacently 25 positioned ladder section. It is 'also possible to use a U shaped clamp of a plastic material, which holds the rungs of the collapsed ladder sections and the ladder section positioned adjacently below the collapsed ladder sections together. The advantage with a clamp is that any of the 30 ladder sections 4a-4d can be collapsed and held my the clamp, whereas the location of a hook or a strap decides which collapsible ladder sections 4a-4d should be collapsed and held together with the ladder section positioned adjacently below the collapsed ladder section. According to 35 yet another alternative, the retaining mechanism or more WO 2006/082032 PCT/EP2006/000856 7 the specifically the locking pins of the retaining mechanism can be used to hold or lock a collapsed collapsible ladder sections 4a-4d in relation to a ladder section positioned adjacently below the collapsed ladder 5 section 4a-4d. In Figs. 4 and 5 the ladder section 4d is collapsed and the strap 15, i.e. the holding means, surrounds the collapsed ladder section 4d and. the ladder section 4e of the ladder leg 2. The strap 15 is preferably attached to 10 one of the rungs 8, 9.and being long enough to surround the rungs of the collapsed ladder sections and the rung of the ladder section positioned adjacently below the collapsed ladder sections. In the embodiment shown in Figs. 4 and 5 the strap 15 is attached torung 9 by a pop rivet or any 15 other suitable fastening means. The strap 15 is fastened by the center of the strap 15 so that the strap extends substantially equallyin both directions from the fastening position. In the end parts of the strap 15, Velcro@ fasteners or similar fastening means are provided that 20 interacts with each other when the strap ends surround the rungs. The ladder sections 4b-4e of the ladder leg 3 are suitably designed with deeper rungs 8, 9, 11 (see Figs. 3 and 5) to provide an extra foot support compared with the 25 rungs of the ladder sections of the ladder leg 2. The rungs are suitably made of an extruded aluminum profile. In the above embodiment showing the converted ladder, i.e. the use of the ladder as a straight ladder, at least one collapsible ladder section 4a-4d of the first ladder 30 leg 2 is collapsed to enable the ladder to be used as a straight ladder. However, it is also possible to keep all ladder sections 4a-4d of the first ladder leg 2 extended and fold in the ladder leg 2 to be adjacent and parallel to the second ladder leg 3. The holding means 15 can in that 35 case be used to maintain the two ladder legs 2, 3 in the WO 2006/082032 PCT/EP2006/000856 8 adjacent and parallel position. The lower ladder section 4e of the second ladder leg 3 could in that case be longer than the lower ladder section 4e of the first ladder leg 2 so that both lower end parts of the two ladder legs 2, 3 5 are supported by the ground at the same time. In Figs. 6-8 the collapsible stepladder shown having fewer collapsible ladder sections is provided with a lock ing device 20. The locking device 20 comprises a first part 21-and a second part 22. The first part -21 is pivotally 10 connected to a rung 8 of the first ladder: leg 2 in one end, preferably the rung 8 of a ladder section. located closely below the hinge connection 5. The second-part"22 is similarly pivotally connected to a corresponding rung 8 of the second ladder leg 3 in one end, preferably the rung 8 15 of a ladder section located closely below the hinge connection 5. The other ends of the firstiand.the second parts 21, 22 are lockably and foldably connected to each other. In the connection between the first and the second parts 21, 22 a locking part 23 is also arranged having a 20 handle portion 24 extending upwards. The locking device 20 serves to secure that the ladder legs 2, 3 of the stepladder 1 are not folded together unintentionally when the stepladder 1 is in use. As the collapsible ladder sections of the stepladder 1 are 25 extended and the fully extended ladder legs 2, 3 are unfolded to the use mode, the first and second part 21, 22 of the locking device 20 are unfolded to constitute an almost straight and horizontal part between the rungs 8 of the corresponding ladder sections of the stepladder 1. By 30 pulling the locking part 23 upwards by the handle portion 24, the first and second part 21, 22 of the locking device 20 are locked in relation to each other by the locking part 23 and any external force of normal magnitude on the stepladder 1 will not result in that the ladder legs 2, 3 35 are folded together and potentially putting any user using WO 2006/082032 PCT/EP2006/000856 9 the stepladder 1 in a hazardous position. In Fig. 6 the locking device 20 is in the locked position. To unlock the locking device 20, the handle portion 24 is pushed downwards thereby moving the ends of the first 5 and second parts 21, 22 of the locking device 20 downwards and enabling the ladder legs 2, 3 to be folded together if so desired. As the locking device 20 in its entirety is arranged inside the ladder bars 6, 7 the locking device 20 is 10 protected from any external forces during handling of the stepladder 1. Moreover, as the first and second parts 21, 22 of the locking device .20 are- arranged on a small pro truding part of the -short ends of the rungs 8, the locking device 20 can be folded: without. interfering with the tele 15 scopically collapsing-functionality of the stepladder 1, but the locking device 20 will follow the ladder sections downwards as the ladder. sections are collapsed. Figs. 7 and 8 clearly show that the locking device 20 is arranged inside a space defined by the ladder legs 2, 3, more 20 specifically by the ladder bars 6 or 7 of the ladder legs 2, 3 and the rungs 8 of the ladder sections. The invention is not limited to the embodiments described above and shown on the drawings, but can be supplemented and modified in any manner within the scope of 25 the invention as defined by the appended claims. 30

Claims

1. A collapsible stepladder (1) comprising a first and a second ladder leg (2, 3), where the legs (2, 3) are 5 hingedly connected to each other in one end, and where each of the ladder legs (2, 3) comprises several ladder sections (4a-4e), and where each section (4a-4d) comprises two ladder bars (6, 7) arranged parallel to each other and interconnected at one end by a rung (8) to form a U-shaped 10 ladder section, furthermore each ladder.;section (4a-4d) are telescopically inserted into a lower ladder; section to form a collapsible ladder comprising at least three ladder sections, where the second ladder leg (3) is. provided with asupport part (12) in one end,.the support part (12) being 15 telescopically extendible from the ladder.,leg (3) to form an extension ladder of the ladder leg. (3), wherein the support part (12) projects above ahinge (5) inter connecting the two ladder legs (2, 3) , characterized in that the collapsible stepladder (1) is arranged to be 20 converted to a straight ladder.

2. A collapsible stepladder (1) according to claim 1, wherein the first ladder leg (2) is provided with a holding means (15) to keep one or several collapsible 25 sections (4a-4d) in a collapsed position.

3. A collapsible stepladder (1) according to claim 2, wherein the holding means (15) is a strap or hook attached to one of the ladder sections (4a-4e) of the first 30 ladder leg (2) to hold a collapsed ladder section (4a-4d) together with a ladder section positioned adjacently below the collapsed ladder section (4a-4d).

4. A collapsible stepladder (1) according to claim 35 2, wherein the holding means (15) is a U-shaped clamp WO 2006/082032 PCT/EP2006/000856 11 arranged to hold the rungs (8, 9) of a collapsed ladder sections (4a-4d) and the ladder section positioned adjacently below the collapsed ladder section (4a-4d) together. 5

5. A collapsible stepladder (1) according to claim 1, wherein the collapsible stepladder is arranged to be converted to a straight ladder by means of the hingedly connected ladder legs (2, 3), enabling completely extended 10 ladder legs' (2,-3) to be parallelly arranged.

6' A collapsible stepladder (1) according to claim 5, wherein a lower ladder section (4e) of the second ladder leg (3) is longer than the lower ladder section (4e). of the 15 first ladder leg (2) .

7. A collapsible stepladder (1) according to any of the preceding claims, wherein the support part (12) comprises at least one collapsible ladder section (12a, 20 12b, 12c).

8. A collapsible stepladder (1) according to any of the preceding claims, wherein the support part (12) is provided with means to hold tools, paint or other working 25 materials.

9. A collapsible stepladder (1) according to any of the preceding claims, wherein the two ladder legs (2, 3) are connected by a flexible link (14), provided between 30 corresponding ladder sections (4b-4d) of the ladder legs to prevent the ladder legs (2, 3) of the stepladder from splaying apart during use.

10. A collapsible stepladder (1) according to any of 35 the preceding claims, wherein the two ladder legs (2, 3) WO 2006/082032 PCT/EP2006/000856 12 are connected by a locking device (20), provided between corresponding ladder sections (4b-4d) of the ladder legs to prevent the ladder legs (2, 3) of the stepladder from moving in relation to each other during use. 5

11. A collapsible stepladder (1) according to claim 10, wherein the locking device (20) is arranged with one end of a first and a second part pivotally attached, respectively, to one side of corresponding rungs of 10 corresponding ladder sections '(4b-4d) of the two ladder legs (2, 3), and where the first and second parts are lockably and foldably connected to each other in another end. 15

12. A collapsible stepladder (1) according to claim 10 or 11, wherein the locking device (20) is arranged to be folded so that the-locking.device (20) in a folded mode is stored in the space between the ladder legs (2, 3). 20

13. A collapsible stepladder (1) according to any of the preceding claims, wherein at least one of ladder legs (2, 3) of the stepladder is provided with means (10) for improving lateral stability. 25

14. A collapsible stepladder (1) according to claim 13, wherein the stabilizing means is a ladder base ((10) attached to the lower end of the ladder bars (6, 7) of the lowermost sections (4e) of the ladder leg and extending between the ladder bars. 30