EP1657399A2

EP1657399A2 - Portable ladder stabilizing accessories

Info

Publication number: EP1657399A2
Application number: EP05380233A
Authority: EP
Inventors: Giulia Escaleras Escalibur S.L. Piervitali
Original assignee: Escaleras Escalibur SL
Current assignee: Escaleras Escalibur SL
Priority date: 2004-11-12
Filing date: 2005-10-20
Publication date: 2006-05-17
Also published as: ES2297961A1; ES2298018B1; ES2297961B1; EP1657399A3; ES2298018A1

Abstract

Stabilizing accessories (1) which, in principle, adapting the measurements and shapes of some elements which comprise them, are applicable to portable ladders (2), whether a single ladder or a stepladder, with one or more climbing sections, and which increase the lateral stability thereof and permit them to be positioned according to different forms adapting to the requirements of each situation. The stabilizing accessories (1) comprise a connector (5) which is fixed to the outer face of the side beam (3) of the portable ladder (2) and an elbow (13) joined at one end to the connector (5) and at the opposite end to a support element (14), which acts as a support on the ground.

Description

OBJECT OF THE INVENTION

The present invention relates to accessories that, installed on a portable ladder, increase the lateral stability thereof, therefore increasing the safety of the user who is positioned on said ladder.
The portable ladder stabilizing accessories object of this invention may be installed on any conventional ladder, provided the following is borne in mind: the inclination of the side rails of the ladder, the rung profile and the distance between them. Therefore, the adaptation of some constructive elements of the stabilizing accessories to the three points indicated above, permits positioning these stabilizing accessories on both single ladders, with one or more sections, and stepladders, with one or more climbing sections.

BACKGROUND OF THE INVENTION

Given the extensive range of application of portable ladders, which are used both in professional activities (painters, electricians, etc.), as well as in the domestic range (small household repairs, activities related to DIY, etc.), a multitude of types of ladders have been developed which are adapted for specific applications.
Ladders can basically be classified in single ladders (single, connectable or extension) and stepladders (with one or more climbing sections). All these types of ladders have the main drawback of the lower level of lateral stability they have, which may cause falls and accidents, which are increased in the event that the ladder rests on uneven surfaces.
Indeed, whilst the European Standard EN 131- 1 and 2, which are not compulsory in Spain, indicates how ladders should be manufactured, it does not cover how to use them. This standard indicates that some types of ladders have to have a stabilizing base to avoid overturning laterally, but experience demonstrates that these bases are sometimes insufficient. For example, when the user is five metres or more off the ground on a stepladder, with only the support of the legs and the stabilizing base thereof, a badly judged movement, a heavy tool or any accidental bump the ladder receives may cause the lateral overturning thereof.
To solve this problem, devices are known which permits increasing the safety of the ladders whereon they are installed. The incorporation of anti-slip devices, on the base of the ladder, are common, with the aim of avoiding it from slipping, as well as support or hooking devices on the upper part of the single ladders. As a more complex development, the existence is known of ladders, fixed-mounted on a metal structure constructed from a steel profile rectangle, resting on wheels and feed screws, with support plates. This equipment, whereby considerable working heights can be reached safely, are very heavy, difficult to move and very costly.
Through the Spanish document ES 2 193 068 T3 a stabilizer is known for ladders which comprises a rigid base, which has a linear groove, which runs parallel to the wall against which the ladder rests and two fastening devices which, fixed to the side beams of the ladder, are introduced inside said groove. The possibility of extending the rigid base, displacing the supports on which it rests, increases the lateral stability of the ladders, while making the lower surface of the supports in a material such as vulcanized rubber increases the resistance to slipping and therefore increases the front stability of the ladders. In contrast to these undoubted advantages, this invention has several drawbacks, among which is noteworthy the fact that its installation is very complex, as it is necessary to screw the fastening devices to the side beams of the ladder each time one wants to use the stabilizer or leave them permanently installed, thus rendering the ladder useless without the base. Furthermore, the fact that it can be exclusively be used on single ladders limits its scope of application.
Likewise, a "Ladder stabilizer" is known, as is disclosed in the Spanish document ES 2 030 731 T3. This device serves to provide a secure support on the ground, with the ladder in use, irrespective of the size and shape of the side beam of said ladder or the presence of projections on the outer side face of the side beam. The device thus has an advantage over the stabilizer analysed above in that it can be coupled to any model of single ladder, having for this a fastening part which is fixed to the side beam and a footing, connected to the fastening part. The fastening part also has two projections of adjustable length which extend towards the outside of said part, positioned so that the side beam can pass freely between them and be adjusted to the respective faces of the beam edge, when the device is rotated around an axis parallel to the rungs of the ladder. Despite the fact that this device has advantages with respect to the previous one, it has the drawback that, as is observed in the figures, it is only applicable to single ladders and not to stepladders.
In the light of the deficiencies of the stabilizing elements which comprise the current state of the art, the objective of the present invention is to develop accessories to stabilize ladders, which resolve the aforementioned drawbacks and increase the safety level of the ladders, increasing their lateral stability. In this way, it better complies with the Minimum provisions of health and safety at work, set down in Spain in Royal Decree 486/1997 of 14 April.

DESCRIPTION OF THE INVENTION

The object of the present invention is to develop stabilizing accessories for ladders, which may be applied to varied models of portable ladders, whether they are single ladders with one or more sections or stepladders with one or more climbing sections; in short, all those ladders which use rungs, of different section, forming a cavity on the outer face of the side beams. These stabilizers can be applied to any portable ladder, of any model, make, measurement and material (aluminium, iron, fibreglass, plastic, etc.), provided that some constructive elements of the stabilizing accessories, object of this invention, are adapted to the gradient of the side beams of the ladder, to the profile comprising the rungs and to the distance between them.
The invention, which is described below, has the purpose of providing some types of portable ladders for professional use (without excluding household use) with stabilizers which provide the ladders with high stability, permitting the user to safely and comfortably work at a height. These accessories to stabilize portable ladders, provide a very extensive support base, forming a virtual rectangle or square, within which the ladder is situated. In this way, the user, equipped with a helmet and suitable harness, can safely work several metres off the ground, with almost the same convenience that he would enjoy if he was working on scaffolding. Compared to said scaffolding these accessories, to stabilize ladders, object of this invention, stand out as they are very easily assembled accessories, which allow a very high ladder to be assembled and dismantled in a few minutes and even transport it on a car roof rack, also being a considerably more economic solution than the use of scaffolding. It is evident that a ladder equipped with these stabilizing accessories cannot completely replace scaffolding, but, in many cases, it can be used alternatively, more simply and economically, e.g. changing the bulb in the centre of a warehouse several metres of the ground.
The use of these stabilizing accessories prevents the ladder from moving backwards, therefore remaining fixed and stable in the position in which it has been placed.
One of the great advantages of the ladder stabilizing accessories, object of this invention, is, as has been previously mentioned, their adaptation to different types of portable ladders. These stabilizers, conveniently adapted, as stated above, can be applied to the ladders without them needing modifications of any kind, i.e. they can be applied to standard ladders included in one of the following types (according to the European Standard EN 131-1 of 1993):

One-piece leaning rung ladder
Sectional ladder
Extending ladder.
Push-up extending ladder.
Standing run ladder.
Combination ladder.
Step ladder.
Leaning step ladder.
Standing step ladder.
Wide-rung stepladder

Neither does this exclude other types of ladders provided by the current state of the art or which may be developed in the future.
The portable ladder stabilizing accessories, which form the object of this invention, aim to make up for the shortages of the ladder stabilizers known up the present and which have been analysed in the previous section. In this sense, these stabilizers are easily installed on the ladder side beams, increasing their lateral stability and therefore, greater safety, preventing them from overturning, whether the ladders are single or stepladders, with one or more climbing sections, further enabling the adaptation of these stabilizers to uneven ground, if there is a certain gradient or it is rough terrain (e.g. when work is performed in the open air).
The portable ladder stabilizing accessories, object of this invention, basically comprise two assemblies of elements: the first of these assemblies has the function of fastening these stabilizers or supports to the ladder, whilst the second assembly are the actual supports, which extend from the fastening assembly to the ground. The joint between the fastening assembly and the support assembly can be of different types (welding, nuts and bolts, grips, etc.), provided that said joint guarantees both assemblies are safely joined, eliminating the possibility of misalignments in this joint, which may be the cause of an accident, thus invalidating the function of the stabilizing accessories.
As has previously been stated, the accessories to stabilize portable ladders increase the stability of different types of ladders. A possible first application consists of installing two of these stabilizers on the side beams of a single ladder which rests on vertical surfaces, such as walls. This thus increases the lateral stability of the ladder, making it difficult for it to laterally overturn.
In the event that it is necessary to perform work at a height, at a point far from any vertical support plane, such as for example the central area of a warehouse, it will logically be necessary to use a stepladder, whether it has one or more climbing sections. In this case, as with the previous one, it is desirable to increase the lateral stability of the ladder to avoid accidents basically caused by the person who is on the ladder moving sharply or possible bumps that it may receive, due to the work he is performing around him. The installation of four accessories to stabilize the ladder, one on each side of the beam thereof, increases the points of support on the ground, whether the ladder is supported on a smooth surface or an irregular surface. Likewise, these stabilizers increase the lateral stability of the ladder as it increases the number of supports on the floor, which increases the area covered thereby, substantially increasing the torque necessary to be applied before it laterally overturns.
A third way of positioning the accessories to stabilize the ladder arises from the need to increase safety during the use of a stepladder, with one or more climbing sections, which is positioned against a wall, i.e. when the ladder, without resting on it, is practically right up against it, with the rungs of all its sections forming a 90° angle with the wall. Logically, this installation of the ladder beside a wall may involve, in some cases, the need to dismantle the horizontal base that the stepladders usually incorporate on the widest, lowest section. In this case it is obvious that the installation of four supports would hinder the approximation of the ladder to the wall, for which reason only two stabilizers would be installed on the side beams of the two lower sections, which are furthest from the wall. In this way, the ladder is secured by one of its sides with the stabilizing accessories, whilst, on the opposite side, the wall prevents it from overturning.
In the three previous forms of application, not only is the lateral stability of the ladder increased, preventing its lateral overturning, but the portable ladder stabilizing accessories, object of this invention, enable the adaptation of the ladder to the unevenness of the ground, a possibility which acquires maximum importance when work is performed outside, where it is more typical that the ground is uneven. To do this, the stabilizers have, on their lower end, in the area close to the base or plate, which acts as a support on the floor, an endless screw-check nut system, which permits regulating the height of each support, independently from the others, thus overcoming the unevenness of sloping or rough ground, typical of a construction site, where ladders are commonly used. In this aspect, it is important to correctly level the ladder, for which the use of a spirit level is appropriate, adjusting the height of the supports until the ladder, in its use position, has its rungs horizontal to the ground and its weight rests on the largest number of possible points, bearing in mind the supports of the ladder, the two supports provided by the horizontal base, the stepladders incorporate and the additional support points which the stabilizing accessories provide.
It includes the possibility of using a set of weights, which conveniently placed on the stabilizers, as will be seen further on, consolidate the ladder on the ground, avoiding it from overturning.
The possibility of wheels can also be considered, with or without brakes, on the ground supports, instead of plates or together with them. Therefore, the stabilizing accessory can rest on the ground using a plate, a wheel or both, according to well-known construction techniques on scaffolding, cranes, etc. The use of wheels is of great use in moving the extended ladder from one place to another without dismantling it.

DESCRIPTION OF THE DRAWINGS

To complement the description being made and with the aim of aiding towards a better understanding of the characteristics of the invention, in accordance with a preferred example of embodiment thereof, a set of drawings is attached as an integral part of said description, wherein, with an illustrative, non-limiting character, the following has been represented:

Figure 1.-: It shows a perspective view of two portable ladder stabilizing accessories installed on a single ladder resting against a wall.
Figure 2.-: Its shows a perspective view of four portable ladder stabilizing accessories installed on a stepladder.
Figure 3.-: It shows a perspective view of two portable ladder stabilizing accessories installed on a stepladder beside a wall.
Figure 4.-: It shows a semi-exploded view of two portable ladder stabilizing accessories, before being installed on the side beams of a section of single ladder, according to figure 1, or stepladder, according to figure 2.
Figure 5.-: It shows a semi-exploded view of a portable ladder stabilizing accessory, before being installed on the side beam of a stepladder, according to figure 3.
Figure 6.-: It shows a partial perspective view, in detail, of a portable ladder stabilizing accessory installed on the side beam of a ladder viewed from the exterior side.
Figure 7.-: It shows a partial perspective view, in detail, of the installation of a portable ladder stabilizing accessory viewed from the interior of the side beam of a ladder, on the inner side, having made cuts on the rungs for better compression.
Figure 8.-: Shows the cut according to the A-A plane represented in figure 6.

PREFERRED EMBODIMENT OF THE INVENTION

In the light of the figures, we can observe therein an example of embodiment of the invention, which consists of stabilizing accessories (1) for a portable ladder (2), which comprise a first assembly, called fastening assembly, and a second assembly or support assembly. Despite the fact that the two assemblies are joined by a firm joint, they will be described separately, as they have different functions. In the particular embodiment described below, and which is represented in the figures, it has been considered that this joint is welded, although other types of joint (screws, use of grips, etc.), which guarantee the correct fastening between both assemblies, are not rejected.
The fastening assembly, so called as it is the assembly of elements which permits installing each one of the stabilizing accessories (1) on the portable ladder (2), fixing it to the corresponding side beam (3), comprises a connector (5), two threaded rods (6), two nuts (7) and two keeper pins (8). The two threaded bars (6), if two stabilizers are mounted, each on one side of the ladder, are common to the fastening assembly of the other side of the ladder (single ladders and stepladders). If the fastening assembly is mounted as indicated in figures 3 and 5, which refer to ladders against the wall, this will further comprise two bushings and corresponding washers by way of tips (12), another two nuts (7) and another two keeper pins (8).
The support assembly, which will be analysed in greater detail further on, comprises an elbow (13) by way of extension and a support element (14).
The connector (5) of the fastening assembly is designed to be adapted to the side beam (3) of the portable ladders (2) and basically consists of a metal part constituted from an L-shaped steel strip. On its inner face, which is opposite the side beam (3), it has two insertion pieces (9), welded at their ends. These insertion pieces (9) are constituted from a steel cylinder, welded on a washer, welded to the L-shaped part and have a through-bore. The external diameter of the insertion pieces (9), and the distance between them, are such that they can be manually introduced, but without looseness, in two of the square hollows formed by the inside of the ladder rungs and which appear on the outer face of the side beams. If we consider the L-shaped connector (5) as if it was a right-angled triangle, with the ladder in its position of use, its greatest side must be perpendicular to the ground. Logically, this is only possible if the ladder maintains the working angle indicated and established by the manufacturer. In this preferred embodiment, these insertion pieces (9) have been represented as cylindrical bushings, as in this case the ladder rungs (4) are square profiles. Logically, the shape and dimensions the insertion pieces adopt (9) will be determined by the rung profile of each ladder (rectangular, circular, half-round, trapezoidal, etc.) and their angle so that they tightly penetrate in the rung cavity. Two orifices are present (10) in concordance with the through-bore of the insertion pieces (9), but on the outer face of the connector (5). On this same face, the welding, or the joint which is considered suitable, are made, to guarantee the joint of the fastening assembly to the support assembly.
The two threaded rods (6), also metal, have a greater length than the width of the portable ladder (2), i.e. it is greater than the sum of the internal width (useful distance between the inner faces of the side beams (3)) and the width of the two side beams (3). Diametral orifices are made (11) at the ends of each threaded rod (6), which traverses it. The threaded rods (6), once the connector (5) is inserted, run along the entire width of the portable ladder (2), through the hollow rungs (4), and protrude at the two sides thereof.
In a first assembly, as is represented in figures 1 and 4, two stabilizing accessories (1) are installed in the same section of the ladder. This form of assembly is performed if the stabilizing accessories (1) are installed on a single ladder (figure 1), or on a stepladder with one or more climbing sections, at a distance from a wall (figure 2). The connectors (5) of the two accessories are identical but opposite one another and symmetrical and specular. Each connector (5) is fastened to the side beams (3, 21) by threading the nuts (7) at the ends of the threaded rods (6) which protrude from side beams (3, 21). In this particular embodiment, the nuts (7) are butterfly nuts, commonly called lug nuts, although any other type of nut can be used. Preferably, nuts will be used which can be tightened by hand, due to their speed of manoeuvre and not requiring spanners or any other tightening tool to be used. Once the nuts (7) are threaded, a keeper pin (8) is inserted in each one of the diametral orifices (11) of the threaded rods (6), by way of a grip, which, although it does not have the function of immobilising the threaded joint, does prevent the nuts (7) from falling off if they loosen, thus avoiding the possible loss thereof and the misalignment of the entire stabilizing assembly.
The position adopted by the ladder of figure 1 prevents it sliding backwards thanks to the stabilizers, remaining fixed and stable in the position in which it has been placed.
Figure 5 shows a semi-exploded view of a second assembly of the stabilizing accessories (1). This second form of assembly is suitable when trying to stabilize a stepladder which is positioned against a wall, as is represented in figure 3. Evidently, the pair of stabilizing accessories will be mounted on the side of the ladder which is furthest from the wall. In this assembly, a single stabilizing accessory (1) is installed on each section of ladder, meaning that its fastening to the side beams (3) varies with respect to the previous assembly, although both assemblies have in common that the connectors (5) of the supports are also identical, but specular and symmetrical to one another with respect to an imaginary central vertical axis. The fastening of each connector (5) to the side beam (3), whereon the stabilizing accessory (1) is installed, does not vary, although on the opposite side beam (21), which in this case lacks the stabilizing accessory (1), is completed with cylinders by way of tips (12), similar to the insertion pieces (9) welded to the connector (5). The part with the least diameter of these tips (12), also with through-bores, is introduced in the cavity of the rungs (4), on the outer face of the opposite side beam (21), the part of the tips (12) with the greatest diameter remaining visible. The threaded rods (6) traverse these tips (12) and, as in the previous assembly, they are fastened to the opposite side beam (21) by threading the nuts (7). The installation is finalized by introducing the keeper pin (8) in the diametral orifices (11) of the threaded rods (6).
Having described the composition of the fastening assembly, as well as the assembly thereof on the portable ladder (2), the elements which form the support assembly will now be detailed. As has been indicated above, the support assembly basically comprises a bent rod or part (13) and a support element (14). In this particular embodiment, the bent rod or part (13) is a steel part, normally tubular, which has a first vertical section (15), which is welded to the connector (5). After a pronounced elbow, the second inclined section (16) of the part is extended to the ground and, at its end, is attached to a third section (17), or internally threaded vertical bushing. It includes the possibility of incorporating a support (24) which extends from the first section (15), forming the elbow (13), until the second section (16) of said part, to avoid deformations in the elbow (13), due to the stresses it bears. Other possible configurations of this elbow (13) are not rejected, provided that there is a first section (15) perpendicular to the ground and a second section (16) which extends to the ground, joining the first section (15) to a third section or vertical bushing (17). The angles or curves which this section (16) may describe are variable. Even this section of joint (16) may vary provided that the vertical section (15) is resistant with the support base (14), which is also positioned vertically on the ground.
The support element (14) consists of a threaded feed screw (18), which, on its lower end, has a flat base (19), which rests on the ground. This base (19), normally circular, may also have other geometrical forms. The threaded feed screw (18) is introduced in the vertical bushing (17) of the elbow (13), thus forming an endless screw-check nut system which permits regulating the height of the support element (14). Once the support element (14) is regulated to the desired height, a threaded lock bushing (22), which remains on the vertical bushing (17), is adjusted on the threaded feed screw (18). The possibility has been provided that a cap is incorporated (20), of rubber or similar, on the upper end of the support element (14), which prevents dirt from entering the threaded feed screw (18) and at the same time acts as a protection element against possible injuries such as bumps or cuts, that the upper end of said part may cause. A similar cap (20) may also be inserted in the upper end of the first section (15) of the elbow (13) with the same purpose. Once the stabilizing accessory has been mounted, the support element (14) should be perpendicular to the ground.
Once the stabilizing accessories (1) have been installed on the portable ladder (2) and the height of the support elements (14) has been regulated, it includes the possibility of inserting, through the upper part of each of the threaded feed screws (18), a weight (23) which further increases the stability of the assembly.
The possibility of using wheels, with or without brakes, on the support elements (14), can also be considered, instead of plates or together with them. Therefore, the stabilizing accessory can rest on the ground using a plate, a wheel or both, according to well-known construction techniques on scaffoldings, cranes, etc. The use of wheels is highly useful to move the extended ladder from one place to another without dismantling it.

Claims

Portable ladder stabilizing accessories, designed to be used in pairs, i.e. two by two, on portable single ladders and stepladders, of both one or more sections, and these accessories being removably fastened to the side beams, characterized in that each one of the accessories is constituted from an L-shaped connector (5) whose inner face or surface is fastened to the side beam (3) and to whose outer face or surface a bent rod or part (13) is joined, finished off at its opposite end close to the floor in a internally threaded bushing (17) which grips an endless screw in vertical position in its corresponding support base (19), the L-shaped part preferably being positioned so that the long side thereof is vertical and the short side horizontal with respect to the ground so that the system functions optimally.
Portable ladder stabilizing accessories, according to claim 1, characterized in that the L-shaped connector (5) has joined to it, on its inner face or surface, or applicable to the side beams (3), two through-bushings (9) smooth on the outside, identical to one another, which protrude orthogonally from said surface and are positioned at a distance from one another which coincides with the distance between the orifices of two cross beams (4), either consecutive or not, of the ladder in whose orifices they are introduced, tightly but performed manually and with no auxiliary tool by the assembler.
Portable ladder stabilizing accessories, according to claims 1 and 2, characterized in that the fastening between the accessories of both side beams of the same section of ladder is made by corresponding threaded bars (6) at their ends (11) which, traversing the rungs, either consecutive or not, and the through-bushings (9) of the L-shaped connectors (5), protrude therefrom and are tightened by the classic system of butterfly nut (7) or lug nut.
Portable ladder stabilizing accessories, according to claim 2, characterized in that the threaded rods (6) introduced inside two rungs, either consecutive or not, (4) have a diametral orifice made in each one of their ends to receive a keeper pin (8).
Portable ladder stabilizing accessories, according to preceding claims, characterized in that the bent rod or part (13) comprises a first vertical section (15), joined and non-detachable to the connector (5), a second inclined section (16), which extends to the floor, on a plane which is perpendicular to the plane defined by the connector (5) and an internally threaded vertical bushing (17), wherein a threaded feed screw (18) of the support element (14) is introduced, both elements forming an endless screw-check nut system which permits regulating the height of the support element (14).
Portable ladder stabilizing accessories, according to claim 4, characterized in that they comprise a threaded lock bushing (22) which is threaded to the threaded feed screw (18), once the height of the support elements (14) is regulated, being positioned on the vertical bushing (17).
Portable ladder stabilizing accessories, according to claims 4 and 5, characterized in that between the first section (15), forming the bent part or elbow (13), and the second section (16), of said part, a support (24) extends, which has the purpose of avoiding possible deformations in the elbow (13), due to the stresses it bears.
Portable ladder stabilizing accessories, according to claims 4, 5 and 6, characterized in that they comprise weights (23), which are inserted through the upper part of the threaded feed screws (18), increasing the stability of the assembly.
Portable ladder stabilizing accessories, according to preceding claims, characterized in that the support elements (14) can include wheels, with or without a brake, so that the movement of the ladder is facilitated.
Portable ladder stabilizing accessories, according to preceding claims, characterized in that if the accessories are installed on stepladders (figure 3), when it is positioned with one of its sides right against a wall, the fastening of each L-shaped connector (5) and the corresponding threaded rods (6) is performed by coupling the end of loose bushings (12) which have been introduced in the end orifices of the rungs (4), either consecutive or not, where the rods (6) are, bushings (12), which are similar to those which protrude from the L, symmetrically positioned with respect to the bushings of the L and tightened with the corresponding butterfly nut (7) or lug nut and keeper pin (8) system.
Portable ladder stabilizing accessories, according to preceding claims, characterized in that both the bushings (9) and the cylindrical shaped through-bushings (12) have washers joined to one of their corresponding ends.