EP1914378A1 - Sliding safety ladder for working at height - Google Patents

Abstract

The ladder has a sliding element (C) with bars (5a, 5b) to carry a platform (15) that is articulated on the bar (5b) while pivoting towards front. A rail (20) is formed by a U shaped frame whose branches are articulated on posts (3) around a virtual axis replacing the bar (5a) while pivoting on the rear of the element. The rail is linked to the front of the platform by a rod to constitute a workstation folding and deployment movement control part. A lock blocks the station in one of end positions and is actuated by a hand while another hand controls pivoting of the rail.

Description

The invention relates to the field of sliding ladders with at least two elements or planes, respectively fixed and sliding, each formed by amounts carrying bars and intended to be used for working at height on columns or walls supporting, for example, electrical or communication equipment.

It concerns the ladders which are equipped at the head of the sliding element of a workstation comprising a platform and a railing, as for example in the document GB2195388 , and more especially those in which said platform is foldable against the sliding element.

In the description and the claims which follow the expression "back" designates the part of the ladder facing the operator, while the expression "front" designates the part that is opposite the operator. Work zone.

The addition of a platform at the head of the sliding element to improve the safety of a workstation that can be located at height, revealed numerous disadvantages, both during the assembly and training of the ladder than during its use. These disadvantages are all the more important as the scale extends to a height of up to 5 meters for a ladder with stabilizing feet and 10 meters and more for a ladder in support.

Thus, after the operator has brought the ladder to work, it has positioned it against a vertical support, of pole or wall type or, if the support is not strong enough to accept the support of the ladder, has developed supporting legs around the fixed element, and then sliding the sliding element, it must set up or deploy the platform from its storage position, in which it is folded against the sliding element. This operation forces the operator to climb to the top of the ladder and to perform, from a position where he is resting on a rung, wide movements which, depending on the deployment kinematics, may lead the operator to very unstable positions, even dangerous ones if he has to make a lot of effort.

An object of the invention is to provide a ladder whose actuating movements of the platform are carried out without having to perform movements out of the scale and significant efforts may unbalance or cause instability.

When an operator moves on the platform and comes in particular near its lateral edges, at the limit of the support polygon delimited by the feet of the ladder and either by the support wall, or by the cooperating legs of support legs with the fixed element, its sole mass generates, relative to the base, a pair which, tending to tilt the ladder, creates a pendulous movement very unpleasant and uncomfortable.

Another object of the invention is to provide a platform which, in the deployed state, does not generate any pendulum movement during the movement of the operator on it.

For this purpose, in the scale according to the invention, the last two bars of the sliding element carrying the platform are spaced apart more than the other bars and are structured in axes of articulation, while, firstly, the platform is articulated by its rear end on the penultimate bar of the ladder element with possibility of pivoting towards the front of the element, secondly, the guard is formed by a U-shaped frame whose ends of branches are articulated on the uprights around a virtual axis replacing the last bar of the ladder element, with possibility of pivoting on the back of the element, this guard being connected to the front of the platform by a connecting rod for constituting control of the movements of deployment and folding of the workstation, and that, thirdly, the locking means of this station in each of its extreme positions are constituted by a single spring return latch, operable by one hand when the other hand controls the pivoting of the railing.

With this structure, to deploy the platform, contained in the folded state between the last two bars, the operator having his feet resting on a bar, must, with one hand, unlock the platform and, simultaneously and with the other hand, either push the platform forward to rotate it down, or lift the guard upwards. By the play of the lever arms between the various components of the structure, the effort to be exerted is very small and can not be a source of imbalance of the operator.

When the platform is deployed, it extends on the front of the ladder and the guard on the back. The movements of the operator are limited longitudinally and laterally by the guardrail and can not be performed outside the ladder's support polygon, so can not generate pendulum movements at the top of this scale.

Advantageously, the platform has a defined length so that, when the ladder bears against a vertical support, such as a wall or a post, and forms with the horizontal its normal angle of inclination, between 65 and 75 degrees, its front end does not come into contact with the vertical support.

This arrangement is very important because it allows, with a ladder without support legs and to be applied against a vertical support, such as post or wall, to put the ladder in support, before deploying the platform and, consequently, guarantee the stability of the operator during deployment.

In one embodiment of the invention, one of the uprights of the fixed lower element carries, against its internal face and at eye level, a bubble level forming an inclinometer and making it possible to give the fixed element the bearing the inclination for which the platform is horizontal in the deployed state.

The spirit level is interesting in sliding ladders with support legs articulated on the uprights of the fixed plane, since it facilitates the positioning of this plane during the training of the legs, so before implementation of the sliding plane. It is also interesting in ladders which, equipped with non separable plans, are heavier, because it facilitates the adjustment of their inclination during their training or stitching against a vertical support.

In an application of the invention to ladders with separable planes, the sliding element carrying the platform is the rear plane of the ladder and its movements of deployment or folding are controlled by a rope during the front and under the ladder.

This assembly says "the Italian" is particularly interesting for the scales to be used by one man, because it allows, by separating the elements, to lighten the weight of the burdens to be brought to work. After placement of the lower fixed element and possibly stabilization by supporting legs, the operator sets up the upper element sliding against the fixed element and comes under the ladder to grasp the deployment rope of this element sliding. At the end of the deployment of the ladder, the operator climbs on the rungs safely to deploy the platform.

In another application relating more specifically, but not necessarily, sliding ladders with non-separable planes, the sliding element carrying the platform is the front plane of the ladder and its movements of deployment or folding are controlled by an accessible rope of the back of the ladder.

This type of ladder, which by nature is heavier than the previous one, is intended to be moved and set up by two people. At the end of training, also called stitching, an operator arranged under the ladder straightening slightly to move its end of the support on which it rests, while the other operator, arranged behind the ladder, deploys the sliding element sliding against the lower fixed element by pulling the operating rope. Since this rope is accessible from the rear of the ladder, the pulling force generates a rearward transverse component which helps to move the ladder away from its vertical support and relieves the other operator, reducing the effort he has to make to hold the ladder.

Other features and advantages will emerge from the description which follows with reference to the attached schematic drawing showing several embodiments of the ladder with its platform.
Figure 1 is a perspective view of a first embodiment of the scale, called "Italian", when it is supported by support legs and deployed in front of a pole;
Figure 2 is a partial view, in perspective and on an enlarged scale, of the upper part of another embodiment, when this part is in abutment against a vertical wall and when the platform is being deployed;
Figures 3 to 6 are side views in elevation and reduced scale, showing, respectively, different phases of the mounting of the sliding plane on the fixed plane of the scale of Figure 1 and the deformation of the platform after sliding of the element carrying it
Figure 7 is a partial view partially in section of the lower part of the fixed plane, along VII- VII of Figure 4, during the establishment of the sliding plane;
Figure 8 is a partial sectional side view of the fixed plane showing the inclinometer and the position of the operator's feet on the platform
Figures 9 and 10 are perspective views of the scale of Figure 2 called "French" when it is, respectively, folded into the storage position and deployed in abutment against an electrical pole.

In general, the invention applies to sliding ladders composed of a lower element or fixed plane F and a sliding element or plane C. Each of them is formed by amounts, respectively, 2 and 3, bearing bars 4 and 5. The uprights 2 and 3 are tubular and made, depending on the application, aluminum or composite materials. As for the bars 4 and 5 they are tubular and aluminum.

The scale shown in Figures 1 and 3 to 8 is called "Italian" and has its fixed plane F which is at the front, while its sliding plane C is at the rear. In the version shown, the sliding plane C can be separated from the fixed plane F, for example, to facilitate the transport of the ladder by a single man, by halving the weight to be transported on each trip, for example between a transport vehicle and the point of intervention.

The plane or fixed element F has, near its upper end, on the one hand, two U-shaped slats 11 with unequal flanges, whose large flange 11a is fixed against the outer lateral face of the corresponding upright 2 and, on the other hand, pads 6 of good slip coefficient material, such as PTFE or equivalent. These pads 6 are arranged in front of slides 11 relative to the direction of engagement of the ends of the uprights 3 of the sliding element C in the slides.

The fixed element F of the embodiment shown in FIGS. 1 and 7 is provided at its lower end with a compensating stabilizer 7. This stabilizer is in the form of an inverted V, whose two arms 8a and 8b of the body, carrying sliding lockable legs are fixed on the last bar 4d and are connected to the corresponding upright 2 by fittings 9 (visible in Figure 7). Each fitting 9 is shaped to provide, at the base of the element F, a space 10 whose utility will be specified below.

The sliding element C carries, near its lower end, tabs 12 which, fixed against the external lateral faces of the uprights 3, extend towards the front of the ladder and each carry a roller or roll 13 which can roll against the rear field of the upright 2 of the fixed element F. It is these tabs 12 with their rollers 13 which, by passing through the spaces 10 previously described, allow their rollers 13 to come behind the uprights 2 to guide and retain the element C against that F.

As shown in Figures 1 and 2, the last bars 5a and 5b of the element C are spaced apart by a step S greater than the normal pitch P between bars, to form the storage space of the platform when it is at folded state, shown in Figure 9. These bars 5a and 5b are structured in the form of axes of joints and, more precisely, that 5b is formed by a real bar while the 5a is virtual and is arranged in place of the last bar.

The platform 15 of the workstation is made of metal or plastic material and is articulated by its rear edge 15a on the second to last bar 5b. It is arranged to protrude forward of the ladder as it is deployed. It has in cross section the shape of a U with two side wings 15b projecting upwards. The rear ends of these wings are connected by a vertical and transverse flange 15c, projecting upwards.

The platform is associated with a guard 20 protruding rearwardly and constituted by a U-shaped frame, metal or plastic material, and whose branches 20a are hinged to the uprights 3 about a virtual axis arranged at the lap. lace of the last bar 5a. A connecting rod 23 connects the front part of the bodyguard to the front end of one of the side wings 15b of the platform. The wings 15b are provided, as shown in Figure 8, studs 16 which projecting laterally outwardly from their front ends slide in vertical rails 17, hinged at 18 on legs 19 solder branches 20a of the bodyguard. The two slides 17 are connected by a cross member 21 to form a safety barrier.

The platform can occupy two positions, a storage position, shown in Figure 9 and a working position, shown in Figure 1, in which it can receive an operator. In Figure 2, the platform is in an intermediate position of folding or deployment.

In its two extreme positions, the platform is blocked by a lock 25, spring return. The housing containing the lock is fixed on a tab 26 attached to the inner face of the upright 3 of the ladder and protruding forwardly. The latch 25 cooperates with lugs in the connecting rod 23 and not visible in the drawing.

The scale according to the embodiment of FIGS. 1 and 3 to 7 is brought into two separate elements near the workplace, and then the fixed element F is positioned either by pressing against a vertical support or by means of support legs. support 28, shown in phantom in Figures 1 and 3 to 6.

The operator performing this positioning is assisted by a spirit level 29 which, as shown in Figure 8, is fixed at eye level against the inner face of one of the uprights 2 of the fixed element F to constitute inclinometer. The body of the level is arranged on the upright so that the bubble is between its references when the upright forms, relative to the horizontal H, an angle a having a value of between 65 to 75 degrees and for example of the order of 65 degrees, which is the usual tilt value of a scale.

When the element F is positioned, the element C is brought on it, as shown in FIG. 3. It will be noted that the element C has a length L2 which is less than that L1 of the element F of a value at least equal to the distance T between the lower edge of the slides 11 and the end of the sliding element C. This arrangement allows the operator to easily position the element C on the F, bringing the ends of its uprights 3 on the sliding pads 6, arranged below the slides 11. As a result, as shown in FIG. 4, the tabs 12 coincide with the spaces 10 formed at the bottom of the fixed element F and that, by bringing the plane C closer together of the plane F, as shown in Figure 5, the guide rollers 13 are at the back of the uprights 2. To complete the assembly is sufficient, as shown in Figure 6, to slide the element C on the F using, from below the ladder, a rope 30 hung on a bar of e the element F and passing on a return 31 formed at the top of the element C.

When the upper end of the ladder has reached the working level, the operator climbs close to the platform and, while his feet are resting on a bar, he actuates with a hand the lock 25, in the direction unlocking, while the other hand it controls the deployment, either by raising the guard 20 upwards, or by pushing the platform 15 towards the low. This movement is effortless and smooth, so without giving a feeling of instability and discomfort to the operator. It can then be placed on the platform 15, which, as shown in Figures 6 and 8, by its perfect position above the support polygon, does not amplify the parasitic movements created by the movements of the operator and or by its approach of the edges of the platform.

FIG. 11, concerning a French scale, shows that the length of the platform 15 and its kinematics are determined in such a way that, with the optimal inclination of the ladder, the pivoting movements of the platform 15 are carried out without that its front end can come into contact with the support support, such as wall post or wall, to eliminate any risk of friction, generators destabilizing shots.

FIGS. 2 and 9 to 11 show another form of ladder execution with a safety platform, in which the structure and the mounting of the platform are identical to those described previously, but is distinguished by the application of the invention on a scale called "French", that is to say on a scale whose sliding element C 'is disposed under the fixed element F'.

FIG. 9 shows that the fixed element F 'is less high than the element C' and that the last bar 40 of the sliding element C 'has a shape complementary to that of the pole 41 on which it is intended to be supported . The amounts 3 of the element C 'are each provided with an outer wheel 42 adapted to roll on a vertical wall.

The two elements or planes C 'and F' are not designed to be separated for transport, so that full scale requires at least two people to be moved and brought to work, then erected or stitched.

Its dressing is facilitated by the French assembly since, as shown in Figure 10, the strand 43a of the rope 43 serving for sliding of the element C 'on the element F' is pulled from the rear of the scale by generating on it a transverse force E which tends to spread the scale of the support 41 and reduces the effort that must make the assistant of the operator to hold vertically the elements of the scale during deployment.

The same figure 10 also shows that, for works at high height, the stability of the scale can be increased by interposing stabilization means, between the pole 41 and its fixed lower element F '. These means comprise a stabilizing bar 44 and a strap 48 of tensioning.

The posterior end of the bar 44 is shaped to the shape of the section of the post against which it can be supported and, for example, is provided with a V 45, while its front end 46 is T-shaped with clevises facing downwards and hooking on one of the bars 4 'of the fixed element F'. The body of the bar is composed of two telescopic parts 44a and 44b, provided with locking means 47.

The strap 48 is attached to one of the bars 4 of the fixed element F ', goes to the pole 41, bypasses it at least once and returns to the bar, where it is hooked by generating a tension, in the direction represented by the arrow 49, and tending to bring the element F 'to the post.

Thus positioned and maintained the ladder is very stable, regardless of the height relative to the ground reached by the platform. It then remains for the operator to climb to the platform to put it in working position by proceeding as indicated above.

It is obvious that the stabilizing bar 44 and the strap 48 can also be implemented on the scale of the previous embodiment.

It follows from the foregoing that the platform according to the invention applies without difficulty to different types of ladders and in any case, alone or in combination with accessories, improves the assembly conditions, the stability of the ladder and the safety of the staff.

Claims (10)

Safety sliding ladder for high-rise work consisting of at least two elements (F and C), also called planes, each formed by uprights (2, 3) and bars (4, 5), namely: a fixed lower element (F), and at least one sliding element C that can slide and be locked on the preceding one, said sliding element, removable or not, carrying at its upper end a folding workstation which, formed by a platform (15) with a guard (20). ), is provided with locking means (25) in each of its positions, respectively folded storage and unfolded working, characterized in that the last two bars (5a, 5b) of the sliding element C carrying the platform are more spaced apart as the other bars and are structured in the form of axes of articulation, while, firstly, the platform (15) is articulated by its rear end (15a) on the second to last bar (5b) of the C ladder element with possibility of pivoting forward, secondly, the guard (20) is formed by a U-shaped frame whose legs (20a) are hinged to the uprights (3) about an axis virtual replacing the last bar ( 5a) of the ladder element, with possibility of pivoting on the rear of the element C, this guard being connected to the front of the platform (15) by a connecting rod (23) to constitute a control member movements of deployment and folding of the workstation, and thirdly, the locking means of the workstation in each of its extreme positions are constituted by a single latch (25) spring return actuated by a hand when the other hand controls the pivoting of the guard rail. Safety sliding ladder according to Claim 1, characterized in that the platform (15) has a U-shaped cross-section whose wings (15b) are lateral and vertical and are provided at their front end with a horizontal finger ( 16) protruding laterally outward and slidably mounted in the longitudinal lumen of a vertical slide (17), said slide (17) being articulated by its upper end to the guard (20) and connected to its neighbor by a crossbar (21) to form a safety barrier. Safety sliding ladder according to claim 1, characterized in that the lock (25) is carried by a lug (26) projecting rearwardly from a post (3) of the sliding element C, and the cooperating lugs. with it are provided in the connecting rod (23) connecting the guard (20) to the platform (15). Safety sliding ladder according to Claim 1, characterized in that the platform (15) has a length (P) defined so that, when the ladder bears against a vertical support, wall or column, and forms with the horizontal its normal angle of inclination (a), between 65 and 75 degrees, its front end does not come in the deployed state in contact with the vertical support. Sliding safety ladder according to claim 1, characterized in that one of the uprights (2) of the fixed lower element F carries, against its inner face and at eye level, a bubble level (29) forming an inclinometer and allowing to give the element F carrying the inclination for which the platform (15) is horizontal in the deployed state. Sliding safety ladder according to claim 1, characterized in that the connection between the uprights (2) of the fixed lower element F and the telescopic and V-shaped arms (8a, 8b) of a level-compensating stabilizer (7) is provided by fittings (9) providing, between the lower end of each upright (2) and the end of the corresponding branch of the stabilizer, a transverse space (10) opening laterally and allowing the assembly or disassembly of the two elements C and F, the passage of the rollers (13) which, carried by the sliding element C, guide the sliding bearing against the front portion of the uprights (2) of the fixed element F. Safety sliding ladder according to Claims 1 and 6, characterized in that the sliding element C is shorter than the fixed element F, of a value at least equal to the distance T between the upper end of the the fixed element F of the lower edge of the guide rails (11) carried by this fixed element, and each slide (11) is associated with a sliding shoe (6) arranged downstream of it with respect to the engagement direction of the sliding element on the fixed element. Safety sliding ladder according to claim 1 characterized in that the sliding element C carrying the platform (15) is the front plane of the ladder and its movements, deployment or folding, are controlled by an accessible rope (30) under and through the back of the ladder. Safety ladder according to claim 1, characterized in that the sliding element C carrying the platform (15) is the front plane of the ladder and its movements, deployment or folding, are controlled from the rear of the ladder. ladder by a rope (43). Safety ladder according to Claim 1, characterized in that it comprises a stabilizing bar (44) with an anterior end (45) conforming to the shape of the section of the post against which it can be supported and a rear end ( 46) provided with hooking means on one of the bars of the ladder, and a strap (47) for tensioning by veneering against the pole (41), going from one of the bars to the pole and having a length allowing him to work around it at least once.

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