WO2002042595A1

WO2002042595A1 - Detachable ladder element provided with a platform

Info

Publication number: WO2002042595A1
Application number: PCT/BE2001/000200
Authority: WO
Inventors: Georges Puriks
Original assignee: Belfroid, Laurence
Priority date: 2000-11-24
Filing date: 2001-11-23
Publication date: 2002-05-30
Also published as: BE1013852A6; AU2002215712A1

Abstract

Ladder element provided with a platform (3) which can be mounted on the rungs (5, 6) of a ladder (1), whereby this platform (3) is provided with a holder (18) which must rest on a first rung (5) of a ladder (1) and whereby this platform (3) is provided with at least one support (4) defining a supporting space (27) which is designed for a second rung (6), underneath said first rung (5), whereby this support (4) has fastening means (7) which make it possible to mount said platform (3) in a detachable manner on said ladder (1), whereby said fastening means (7) comprise a locking device (8) which can be moved in relation to said support (4) according to a translation, in such a manner that said supporting space (27) is reduced or enlarged and such that it becomes possible to clamp said second rung (6) in this supporting space (27) between the support (4) and said locking device (8).

Description

DETACHABLE LADDER ELEMENT PROVIDED WITH A PLATFORM

The invention concerns a ladder element provided with a platform which can be mounted on the rungs of a ladder, whereby this platform is provided with a holder which must rest on a first rung of a ladder and whereby this platform is provided with at least one support defining a supporting space which is designed for a second rung, underneath said first rung, whereby this support has fastening means which make it possible to mount said platform in a detachable manner on said ladder.

Such a ladder element enables a person who has to carry out work by means of a ladder to stand in a stable manner with both feet on the platform of the ladder element, whereby this person has both hands free to carry out his work. With the different types of ladders which are currently available on the market, the distance between the successive rungs varies depending on the type of ladder. In order to make sure that the existing ladder elements can be mounted on these different types of ladders, they are provided for example with a rotating locking device which can be fixed in different positions as a function of the distance between successive rungs of a ladder. Such a ladder element is described for example in GB-A- 2 161 529.

Moreover, the diameter of the rungs of different types of ladders usually varies. Thus, it is dangerous to use a ladder element which has been designed for a specific type of ladder on another type. Further, many existing ladder elements have a relatively small platform, such that a person standing on this platform gets insufficient support or stability. Existing ladder elements which do have a sufficiently large platform are dangerous to use, since a person has to take a relatively large step to move from a rung under the ladder element up to the platform. Conversely, it is dangerous to move from the platform to the underlying rungs since the latter are not visible and are situated relatively far from the front end of the platform. The invention aims to remedy these disadvantages by means of a ladder element which can be very easily placed on any type of ladder, whereby a person can stand in a stable manner on the platform. Further, the ladder element according to the invention makes sure that a person can move in a simple and safe manner from the platform to the underlying rungs of the ladder and vice versa.

To this aim, said fastening means contain a locking device which can be moved in relation to said support according to a translation, in such a manner that said supporting space is reduced or enlarged, and such that it becomes possible to clamp said second rung in this supporting space between the support and said locking device. Practically, said locking device has the form of a plate and it has guides working in conjunction with said support and making it possible to shift the locking device in relation to the latter up against said second rung.

According to a preferred embodiment of the ladder element according to the invention, said guides consist of a longitudinal recess through which extends a shaft mounted on said support, such that the locking device can move in relation to the support in the direction of said recess.

According to a special embodiment of the ladder element according to the invention, the angle between the longitudinal direction of said guide and a perpendicular connecting line, between said first and second rung, is maximally equal to 75°, and it is preferably smaller than 60°.

According to an advantageous embodiment of the ladder element according to the invention, said support, on the far end opposite to said platform, has a fork with two prongs, whereby said locking device is provided on one of both prongs, such that said second rung can be clamped between this locking device and the other prong.

According to an interesting embodiment of the ladder element according to the invention, said support has a step which extends almost parallel to said platform and which is parallel to the rungs of the ladder when it is mounted on the latter, whereby the distance between the platform and this step, according to the longitudinal direction of said ladder, is of the same order of magnitude as the distance between two successive rungs of the ladder. In an advantageous manner, the distance, in a direction perpendicular to the plane of said ladder, between the front end of said platform and said step is maximally equal to the width of the standing legs of the ladder according to this direction, and this distance is preferably in the order of magnitude of 70 mm. According to a more specific embodiment of the ladder element according to the invention, the distance, in a direction perpendicular to the plane of said ladder, between the front end of said step and the standing legs of the ladder is maximally equal to the width of the latter in this direction, and this distance is preferably in the order of magnitude of 70 mm. Other particularities and advantages of the invention will become clear from the following description of some specific embodiments of the ladder element according to the invention; this description is given as an example only and does not restrict the scope of the claimed protection in any way; the reference figures used hereafter refer to the accompanying drawings. Figure 1 is a schematic front view of a part of a ladder upon which the ladder element, according to a first embodiment of the invention, has been mounted.

Figure 2 is a schematic longitudinal section according to line II-II from figure 1. Figure 3 is a detailed representation to a larger scale of a part from figure

Figure 4 is a detailed representation of a part of the ladder element according to a variant of the first embodiment of the invention.

Figure 5 is a schematic front view of a part of a ladder upon which the ladder element, according to a second embodiment of the invention, has been mounted. Figure 6 is a schematic longitudinal section according to line NI-NI from figure 5.

Figure 7 is a detailed representation to a larger scale of a part from figure 6. Figure 8 is a detailed representation of a part of the ladder element according to a variant of the second embodiment of the invention.

In the different drawings, the same reference figures refer to identical or analogous elements. Figure 1 schematically represents a part of a ladder 1 which rests, for example at a certain angle, against a wall which is not represented in the figures. On this ladder 1 has been mounted a ladder element 2 with a platform 3 extending almost horizontally. The latter is provided with two parallel supports 4.

As is clearly shown in figure 2, the platform 3 rests on a first rung 5 of the ladder 1, whereby the supports 4 extend as of this platform 3 up to a second rung 6 of this ladder 1 situated under said first rung 5.

On the far end opposite to the platform 3, the supports 4 have a fork with two prongs 16 and 17 in between which is defined a supporting space 27 for said second rung 6. These prongs 16 and 17 extend almost according to the longitudinal direction of the ladder 1. When the platform 3 is thus mounted on a ladder, these prongs 16 and 17 extend on either side of the second rung 6, whereas a fork-shaped holder 18 is provided on the bottom side of the platform 3 which rests on the first rung 5 of the ladder 1.

Said supports 4 are provided with fastening means 7 which make it possible to mount the platform 3 in a detachable manner on the ladder 1, whereby the platform 3 occupies a fixed position in relation to the latter. These fastening means 7 comprise a locking device 8 which is fixed to one of the prongs 16 of the supports 4, in such a manner that this locking device 8 can be moved almost crosswise in relation to said second rung 6. Thus, the locking device 8 makes it possible to enlarge or reduce the supporting space 27, in particular the distance between the locking device 8 and the prong 17, as is represented in figure 2, to clamp the second rung 6 between the supports 4 and the accompanying locking devices 8.

The locking devices 8 have the shape of an almost rectangular plate whose far end is folded down over an angle of almost 90° on the top side, such that the respective locking device 8 can be operated via this far end 9. Further, the locking device 8, as is clearly visible in figure 3, has guides 10 and 11 which are almost parallel in relation to one another and which work in conjunction with the support 4 upon which this locking device 8 has been mounted. Each of these guides 10 and 11 consists of a longitudinal recess through which extends a shaft 12, 13 respectively, which is connected to the corresponding support 4.

In the embodiment of the ladder element according to the invention represented in the figures, the shaft 12, 13 respectively, is formed of a bolt 14, 15 respectively, which connects the support 4 to the .locking device 8.

Thus, the locking device 8 can be moved in relation to the support 4 by shifting it in the longitudinal direction of said guides 10 and 11 along the bolts 14 and 15.

The angle which is formed between the longitudinal direction of the guides 10 and 11 and the longitudinal direction of the ladder 1, or in other words the perpendicular connecting line between said first rung 5 and the second rung 6, is maximally equal to 75°.

When a person is standing on the platform 3, due to the weight of this person, a force 19 will be exerted on said second rung 6 via the locking devices 8 in a direction which is almost perpendicular to the longitudinal direction of the ladder 1. Thus, the angle α is selected such that the component of this force 19 in the direction of said guides 10 and 11 is insufficient to overcome the frictional force between the locking devices 8 and the support 4 of the shafts 12 and 13. In this manner is made sure that the locking devices 8 take up a fixed position and that said second rung 6 is clamped between these locking devices 8 and the opposite prong 17 of the support 4.

Thus, the angle α is preferably smaller than 60°, and it will be in particular comprised between 45° and 10°. Good results were obtained with an angle α in the order of magnitude of 30°.

The ladder element 2 is mounted on a ladder by placing said fork-shaped holder 18 on the first rung 5 of the ladder, while the prongs 16 and 17 of the support 4 enclose the second rung 6 on either side. Next, the locking device 8 is moved up to this second rung 6 by pressing it on via the above-mentioned folded far end 9 and by thus subjecting it to a translation, whereby the supporting space 27 is reduced, such that this rung 6 becomes clamped in between the locking device 8 and the prong 17.

According to a variant of the preceding embodiments of the ladder element according to the invention which is not represented in the figures, one prong 17 is formed by the supports 4 themselves, whereas a second prong is made of said locking device 8. In such a case, the angle α can be smaller than 30°, and it can be in the order of magnitude of for example 15°.

Figure 4 represents a variant of the preceding embodiment of the invention. This embodiment is provided with an additional safety locking device 20 which is fixed to a prong 16 of the support 4 in a rotating manner by means of said bolt 14. This safety locking device 20 makes it possible to connect both prongs 16 and 17 of the support 4 to one another, such that said second rung 6 becomes enclosed in the supporting space 27 formed between these prongs 16 and 17 and the safety locking device 20. The latter is locked with the prong 17 by means of a locking pin 21. A very interesting embodiment of the ladder element according to the invention is represented in figures 5 to 7. This embodiment is different from the preceding ones in that it contains a step 22 which is provided on the supports 4.

Thus, figure 5 schematically represents a part of a ladder 1 which rests for example at a certain angle against a wall which is not represented in the figures. On this ladder 1 has been mounted a ladder element 2 having a platform 3 which extends almost horizontally. The latter is provided with two supports 4 extending almost parallel to one another.

The ladder 1 thus contains two almost parallel standing legs 23 and 24 in between which rungs extend. The step 22 extends almost parallel to said platform and to said rungs and is fixed to the prong 16 of the supports 4 situated on the side of the ladder 1 on which a person normally climbs up the ladder 1.

This step 22 prevents a person, when climbing up the ladder 1, from having to take a considerably large and dangerous step in order to move from said second rung 6 to the platform 3. This step 22 also makes sure that a person wishing to leave the platform 3 can move in a simple manner to this underlying step 22.

Further, the distance between the platform 3 and the step 22 in the longitudinal direction of the ladder 1 is of the same order of magnitude as the distance between two successive rungs 5 and 6 of this ladder 1.

The front edge 25 of the platform 3 on the side of the ladder 1 on which a person will climb up this ladder, is preferably situated at a distance C from the step 22, in particular from the front edge 26 of the step 22, which is equal to the width A of the standing legs 23 and 24. This distance C, and the width A, is measured in a direction perpendicular to the rungs and the standing legs 23 and 24 of the ladder 1, or in other words perpendicular to the plane of the latter. For most types of ladders, the distance C is in the order of magnitude of 70 mm.

The distance B between the front edge 26 of said step 22 and the standing legs 23 and 24, in the same direction perpendicular to the rungs and the legs 23 and 24, will preferably be maximally in the order of magnitude of the width A of these legs 23 and 24. The distance B thus amounts to for example 70 mm.

According to an advantageous embodiment of the ladder element 2, the distance B' between the rungs of the ladder 1 and the front edge 26 of the step 22, in the same direction, is maximally equal to the width A. Such dimensions make sure that a person can move in a safe and easy manner from the platform 3 to the underlying rungs of the ladder 1 via the step 22, and vice versa.

Figure 8 shows a variant of the preceding embodiment of the ladder element according to the invention. Hereby is provided an additional safety locking device 20 which is fixed in a rotating manner to a prong 16 of the support 4 by means of said bolt 14. This safety locking device 20 makes it possible to connect both prongs 16 and 17 of the support 4 to one another, such that said second rung 6 is enclosed in the supporting space 27 formed between these prongs 16 and 17 and the safety locking device 20. The latter is locked with the prong 17 by means of a locking pin 21. The ladder element, as described in the preceding embodiments, can for example be cast in aluminium or made of steel plates. If steel plates are used, the edges of these plates resting against the ladder are preferably folded down at an angle of almost 90°, such that the thus formed edge makes sure that the load on the ladder is divided over the width of this edge.

Further, the supports 4 can be hinge-mounted to the platform 3, such that, in order to store the ladder element 2, the supports 4 can be rotated up against the platform 3. In this case, means are provided which make it possible to fix the supports 4 in a specific position in relation to the platform 3, such that this can be mounted on a ladder 1.

Naturally, the invention is not restricted to the above-described embodiments of the ladder element represented in the accompanying drawings. Thus, it is for example not absolutely necessary to provide two supports 4 as described above, but, in certain cases, one support which is fixed for example in the middle of the platform 3 will be sufficient.

Also the length of the supports 4 can be made adjustable, such that the ladder element can be adjusted for practically any type of ladder. Thus, as represented in figure 9, the support 4 may consist of a top part 4' and a lower part 4" whereby the top part 4' is provided with a guide 30 in the shape of a longitudinal recess and the lower part 4" is provided with two bolts 28 and 29 which extend through said guide 30. The length of the support 4 can then be adjusted by moving the lower part 4" thereof in relation to the top part 4' in the direction of said guide 30, whereby the bolts 28 and 29 move in the latter. Thus, the distance D between the holder 18 and the supporting space 27 can be adjusted and, as a consequence, the distance between the front edge 25 of the platform 3 and the step 22 is adjusted correspondingly, for example to the distance between the rungs 5 and 6.

Claims

1. Ladder element provided with a platform (3) which can be mounted on the rungs (5,6) of a ladder (1), whereby this platform (3) is provided with a holder (18) which must rest on a first rung (5) of a ladder (1) and whereby this platform (3) is provided with at least one support (4) defining a supporting space (27) which is designed for a second rung (6), underneath said first rung (5), whereby this support (4) has fastening means (7) which make it possible to mount said platform (3) in a detachable manner on said ladder (1), characterised in that said fastening means (7) comprise a locking device (8) which can be moved in relation to said support (4) according to a translation, in such a manner that said supporting space (27) is reduced or enlarged, and such that it becomes possible to clamp said second rung (6) in this supporting space (27) between the support (4) and said locking device (8).

2. Ladder element according to claim 1, characterised in that said locking device (8) has the shape of a plate and comprises guides (10,11) which work in conjunction with said support (4) and which make it possible to shift the locking device (8) in relation to the latter.

3. Ladder element according to claim 2, characterised in that said guides (10,11) consist of a longitudinal recess through which extends a shaft (12,13) which is mounted on said support (4), such that the locking device (8) can be moved in relation to the support (4) in the longitudinal direction of said recess.

4. Ladder element according to claim 2 or 3, characterised in that the angle (α) between the longitudinal direction of said guide (10,11) and a perpendicular connecting line, between said first and second rung (5,6), is maximally 75°, and is preferably smaller than 60°.

5. Ladder element according to claim 4, characterised in that said angle is smaller than 45° and is preferably in the order of magnitude of 30°.

6. Ladder element according to any of claims 1 to 5, characterised in that said support (4) has a fork with two prongs (16,17) on the far end opposite to said platform (3), whereby said locking device (8) is provided on one of the two prongs (16), such that said second rung (6) can be clamped between this locking device (8) and the other prong (17).

7. Ladder element according to any of claims 1 to 5, characterised in that said support (4) has a fork with two prongs (16,17) on the far end opposite to said platform (3), whereby a first prong (16) is formed by said locking device (8) and a second prong (1 ) is formed by the support (4) itself.

8. Ladder element according to any of claims 1 to 7, characterised in that said support (4) is hinge-mounted in relation to said platform (3), whereby means are provided to fix the latter in a specific position in relation to the platfoπn (3).

9. Ladder element according to any of claims 1 to 8, characterised in that said platform (3) has means, in particular a fork-shaped holder (18), with which the platform can rest on said first rung (5).

10. Ladder element according to any of claims 1 to 9, characterised in that it comprises a support (4) for the platform (3) on two side edges of the platform situated opposite to one another, which extend perpendicular to the plane of the latter.

11. Ladder element provided with a platform (3) which can be mounted on the rungs (5,6) of a ladder (1), whereby this platform (3) must rest on a first rung (5) of this ladder (1) and whereby this platform (3) is provided with at least one support (4) which rests against a second rung (6), underneath said first rung (5), whereby this support has fastening means (7) which make it possible to mount said platform (3) in a detachable manner on the ladder (1), characterised in that said support (4) has a step (22) which extends almost parallel to said platform (3) and which is parallel to the rungs of the ladder when it is mounted on the latter, whereby the distance between the platform (3) and this step (22), in the longitudinal direction of said ladder (1), is of the same order of magnitude as the distance between two successive rungs (5,6) of the ladder (1).

12. Ladder element according to claim 11, characterised in that the distance (C), in a direction perpendicular to the plane of said ladder (1), between the front end (25) of said platform (3) and said step (22) is maximally equal to the width (A) of the standing legs (23,24) of the ladder (1) in this direction, and is preferably in the order of magnitude of 70 mm.

13. Ladder element according to claim 11 or 12, characterised in that the distance (B), in a direction perpendicular to the plane of said ladder (1), between the front edge (26) of said step (22) and the standing legs (23,24) of the ladder (1), is maximally equal to the width (A) of the latter in this direction, and is preferably in the order of magmtude of 70 mm.

14. Ladder element according to any of claims 11 to 13, characterised in that the distance (B'), in a direction perpendicular to the plane of said ladder (1), between the front edge (26) of said step (22) and the rungs (5,6) of the ladder (1) is maximally equal to the width (A) of the legs (23,24) thereof in this direction, and is preferably in the order of magnitude of 70 mm.

15. Ladder element according to any of claims 1 to 14, characterised in that means are provided which make it possible to adjust the length of said support (4) in order to adjust the distance (D) between the holder (18) and the supporting space (27) to the distance between the rungs (5,6) of said ladder.

16. Ladder element according to claim 15, characterised in that said support (4) has two parts (4',4") which can be moved in relation to one another.

17. Ladder element according to claim 16, characterised in that one of said parts (4',4' ') has a guide (30), whereas the other part (4' ',4') is provided with bolts (28,29) which extend through this guide (30) and work in conjunction with it.