EP1416117B1 - Adjustable ladder - Google Patents

Abstract

The adjustable step ladder has two uprights (2) connected by rungs (3). A counter strut (4) is hinged to the uprights and is adjustable in length. The counter strut has a locking brace (5) adjacent to its top to retain the uprights and counter strut in their relative positions. The counter strut can be telescopic.

Description

The invention relates to an adjustable ladder.

Classically, a ladder consists of two uprights connected by bars or sleepers.

Often the amounts are parallel but sometimes the amounts converge towards the top of the scale.

Such is the case of ladders used by window cleaners who often have to support their ladder on the amounts of windows, which amounts are narrow.

Indeed, there is no question of leaning on the glass because it is considered too fragile.

These scales therefore require to have a fulcrum for the top of it.

In some cases, the user of the ladder does not have a fulcrum and he must therefore use another type of scale namely double scales.

This double ladder includes a second ladder articulated on the upper part of the uprights.

This second scale is often in a simplified form consisting of two amounts connected, in particular, at the base by a single cross.

This support or against-support and the ladder, when in the position of use, form in side view a triangle.

To prevent the triangle from opening, generally, a flexible link can limit the opening.

These ladders, at four points of support on the ground, must be used on flat ground.

Indeed, in soft ground, the risk of falling is important.

Sometimes, at the base of these scales, one adds a stabilizer but whose effectiveness is limited.

Ladders are also known whose counter-support is constituted by a simple section so that a support is formed at three points which is favorable to the stability.

A scale according to the preamble of claim 1 is described in US-548670 .

If these scales work perfectly well on a flat ground, when it is tilted, the center of gravity is then displaced and the risk of falling becomes not insignificant.

One of the results that the invention aims is a scale of the aforementioned type that provides a solution to the problems mentioned above.

• en ce que le contre-appui est de longueur variable et,
• en ce qu'elle comprend, à distance de son sommet, un dispositif dit de verrouillage comprenant une pièce de liaison formant un plan articulé sur les montants et guidé en translation sur le contre-appui qui, en position active, s'étend toujours dans un plan parallèle au plan d'appui de l'échelle quel que soit l'inclinaison dudit plan d'appui et verrouille la disposition géométrique des montants et du contre-appui.

For this purpose, the subject of the invention is an adjustable ladder comprising two uprights connected by sleepers or rungs and a counter-support articulated on the uprights, this ladder being characterized:

• in that the counter-support is of variable length and,
• in that it comprises, at a distance from its top, a so-called locking device comprising a connecting piece forming a plane articulated on the uprights and guided in translation on the abutment which, in the active position, always extends into a plane parallel to the support plane of the scale regardless of the inclination of said support plane and locks the geometric disposition of the amounts and the counter-support.

• figure 1 : une vue de face de l'échelle,
• figure 2 : une vue de côté de l'échelle,
• figure 3 : un détail de l'échelle vue de dessus
• figure 4 : une vue partielle de côté de la figure 3,
• figure 5 : une échelle sur un sol pentu,
• figures 6 à 8 : trois variantes de l'invention.

The invention will be better understood using the following description given by way of non-limiting example with reference to the attached drawing which schematically shows:

• figure 1 : a front view of the ladder,
• figure 2 : a side view of the ladder,
• figure 3 : a detail of the ladder seen from above
• figure 4 : a partial view of the side of the figure 3 ,
• figure 5 : a ladder on a sloping ground,
• Figures 6 to 8 : three variants of the invention.

Referring to the drawing, we see a scale 1.

Classically, a ladder 1 consists of two uprights 2 connected by sleepers 3 or steps 3 and a counter-support 4 articulated on the uprights 2.

The sleepers are steps.

As can be seen in the example shown counter-support 4 is constituted by a profile maintained at its upper end between the two amounts 2 above.

This scale comprises a means for limiting the distance of the counter-support relative to the amounts.

In a known embodiment, it is one or two straps.

According to the invention, the scale comprises, at a distance from its vertex A, a so-called locking device 5 which, in the active position, extends in a plane P parallel to the support plane R of the scale and locks the geometric arrangement amounts 2 and counter-support 4.

This device 5 is articulated on the uprights 2 and guided in translation on the abutment support 4.

To simplify the reading, the locking device 5 is not represented on the figure 1 .

The articulation of the counter-support is done on the top of the uprights.

The abutment bears, on its side facing the uprights, a fitting 6 slightly spaced from the face of the abutment behind which the fitting slides the end of a triangular piece 5A whose base is hinged to the rear of the uprights .

This triangular piece 5A is, for example, formed from a round wire folded so that it forms a kind of Vé whose free ends 5C are engaged in 5D fittings carried by the uprights 2 to form a hinge.

This triangular piece 5A has in its opposite portion to the aforementioned articulation a loop 20 which slides along the fitting 6 carried by the counter-support 4.

The loop 20 may be delimited by the round wire and a tablet 5B engaging inside the Vee of the triangular piece 5A.

It could also be a passer defined by the round wire for forming the V e piece and a metal piece attached to this triangular piece.

Transverse stiffeners 21 connect the branches of the V e for better rigidity.

Note that the tip 22 of the Ve is inclined relative to the plane containing the branches and downwards so that the loop 20 slides with a small clearance of operation around the fitting 6 of the counter-support.

This fitting 6 of the counter-support has at least one notch 23 to lock in translation the triangular piece 5A in horizontal position.

A second notch is provided for locking in the folded position.

This locking device makes it possible to give a geometrical resistance to the tripod thus opened.

Note that the front of the uprights is connected by a plate 24 stiffening the assembly at the head and maintaining the axis of rotation which is invisible.

By rendering this triangular arrangement indeformable and by determining a relatively wide support triangle, the user of the scale and its center of gravity always remain in the triangle of levitation.

It is almost impossible to pour laterally.

It should also be noted that, ergonomically, the user is in workstation on the penultimate step in support of the access plan with practically the hip at the height of the hedge and therefore at the appropriate height for the cutting tool.

The ladder can not switch.

Advantageously, the angle defined between the plane defined by the amounts and the counter-support is of the order of 40 °.

The angle V formed by the two uprights is of the order of 22 °.

The length of the abutment and the angles are determined so that the center of gravity is closer to the counter-support so that the weight of the user is oriented towards the profile 4.

For this purpose, the angle G between the ground and the plane containing the amounts is less than the angle F between the ground and the counter-support.

This angle G is about 65 ° and the angle F is 75 °.

It is noted that the fact of using a counter-support in the form of a single profile makes it possible to introduce this profile into the depth of a hedge and therefore to be closer to it.

Advantageously, there is provided at the base of the counter-support a pad 7 or support shoe extended much greater than the section of the section 4 so as to place this counter-support on loose ground.

To increase the resistance of the section 4 or counter-support 4, it is a T-section.

When it comes, in particular, a wooden ladder, this section is either cut in the mass, or consists of two pieces of wood assembled.

In one embodiment, the first sleepers from the bottom are connected by a bar 8 of load recovery avoiding in particular a risk of bending of the longer sleepers.

Advantageously, the face of this bar 8 facing the counter-support will present a groove to partially accommodate the counter-support.

The rear of this bar 8 may be provided with a fastening means of the profile such as a system loops and hooks, which may be partially housed in the aforementioned groove.

According to the invention, the counter-support 4 is of variable length so that the horizontality of the steps can be maintained even if the ground is sloping in one direction or the other.

It therefore comprises a means 40 of adjustment.

Of course, you have to place your ladder in the direction of the slope and not on the slope.

In a first solution, the counter-support 4 is formed of at least one telescopic element with a locking means 41, either stepwise or at any point.

Depending on the material used, the counter-support 4 may consist of two nested tubes but a more resistant solution and to implement full profiles is described below.

In one embodiment, the abutment 4 comprises, on the one hand, a main branch 4A which, extending from the top of the ladder, is of shorter length than the uprights and, on the other hand, a secondary branch 4B consists of two sections held apart by 4D legs, this secondary branch to cap the main branch.

Holes 50 in the two branches come into coincidence to introduce a pin 51 and thus to lock the translation of the branches.

In one embodiment, the abutment 4 comprises, on the one hand, a main branch 4A which, extending from the top of the ladder, is of shorter length than the uprights and, on the other hand, a secondary branch 4B consisting of a profile having a longitudinal groove 4E coming to house the main branch, one or more tabs closing the entrance of the groove to maintain the second branch on the first.

Advantageously, use a first branch 4A having a T-section so that the inner faces 4G of the horizontal arm of the T participate in guiding.

Such solutions make it possible to provide a counter-support of variable length with all types of material, such as wood, composites, aluminum, etc.

The lengths of the branches will be determined so that the length of the counter-support may be shorter than the length of the uprights or be greater.

The range of variation may be of the order of a meter or more.

The skilled person is able to choose this beach.

Claims (5)

1. An adjustable ladder comprising two uprights (2) interconnected by cross-members (3) or rungs (3), and a prop (4) hinged to the uprights (2), the prop (4) being of variable length, the ladder including, at a distance from its top (A), a locking device (5) comprising a connection part forming a plane that is hinged to the uprights (2), said ladder being characterized in that the plane of the connection part is guided to move in translation along the prop (4), said locking device, in the active position, always extending in a plane (P) parallel to the support plane (R) of the ladder regardless of the angle of inclination of said support plane (R) and locking the geometrical configuration of the uprights (2) and of the prop (4).
2. A ladder according to claim 1, characterized in that the prop (4) is formed by at least one telescopic element with locking means (41), operating either stepwise or continuously.
3. A ladder according to claim 2, characterized in that the prop (4) comprises firstly a main branch (4A) that extends from the top of the ladder over a length that is shorter than the length of the uprights, and secondly a secondary branch (4B) constituted by two section members spaced apart by tabs (4D), said secondary branch overlying the main branch.
4. A ladder according to claim 2, characterized in that the prop (4) comprises firstly a main branch (4A) that extends from the top of the ladder over a length that is shorter than the length of the uprights, and secondly a secondary branch (4B) constituted by a section member presenting a longitudinal groove (4E) receiving the main branch, one or more tabs (4F) closing the inlet of the groove in order to hold the second branch on the first.
5. A ladder according to claim 2, characterized in that the prop (4) comprises firstly a main branch (4A) that extends from the top of the ladder over a length that is shorter than the length of the uprights, and secondly a secondary branch (4B), the first branch (4A) comprising a T-section member such that the inside faces (4G) of the horizontal branch of the T-shape contribute to guidance.

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