EP0803466A1 - Method and device for safety ascending to a cab, in particular on a tower crane - Google Patents

Abstract

The raised driving cabin of a tower crane is accessible through a mast comprising sections (10-12) equipped with several lateral access ladders (13,14,15). The secure access consists in utilising an individual protection nacelle (17) which can move along the mast. The nacelle which is accessible from the outside enables the crane driver to stand inside it. The nacelle is held and guided on successive ladders and moved along the mast by a harness resting on the shoulders of the crane operator. A compensator hoist (18) balances the weight of the nacelle and a winding drum (19) is used to immobilise it.

Description

The present invention relates to a method for secure access to an elevated driving position, more particularly to the cabin of a tower crane. It also relates to a device, intended for the implementation of the method. This invention finds its application in particular for access to the cabin of tower cranes with automatic assembly, telescopic or foldable mast, used on building construction sites.

In service, the cabin of such a crane is generally placed at the top of the mast, so that the crane operator, taking place in this cabin for driving the crane, can have good visibility on all work operations. To access the cabin, the crane mast is traditionally equipped with fixed ladders and protective cages, placed either inside the mast when the cross section of this mast is sufficient for the crane operator to pass , or outside the mast when the cross section of the mast is insufficient, which is often the case for self-erecting cranes.

In all cases, the ladders must include rest stops, placed at levels such that each flight of ladders does not exceed an authorized value. Preferably, the successive flights of ladders are offset laterally with respect to each other, to ensure better ergonomics. However, while climbing or descending ladders, the crane operator is not immune to a fall inside the crinoline, from a height of up to several meters, inside the crinoline . Fixed crinolines are therefore not perfect protections against the risk of falling.

In addition, in the case where the ladders and the crinolines are arranged outside the mast, the crinolines in particular have a high wind resistance, which limits the mechanical resistance and the operating range of the crane in service. The presence of external crinolines also implies additional bulk which hinders the folding of the crane into the transport position, as well as increased vulnerability.

To overcome some of the above drawbacks, an embodiment is known from European patent application No. 0.175.052 in which the cabin is slidably mounted along the crane mast, and in which the crinoline device for access ladders under the cabin, which is made up of hoops that also slide along the mast and are connected to one another by cables or straps. In the crane transport position, the cabin is lowered at the foot of the mast, and the hoops of the crinoline device stack on top of each other, thus presenting a space requirement that is as small as possible. Such an embodiment is advantageous for the road transport of the crane, but it presents technical difficulties and a significant additional cost, in particular to ensure the correct guiding of the crinoline arches during sliding, and the maintenance in position of these arches. Another vertically movable complete cabin device is known from Swiss Patent No. 665,825.

There are also known devices for accessing the top of the mast of a crane, in particular of high height, constituted by a real elevator car circulating inside the mast - see international patent application No. WO 92/18412 . Such a solution is conceivable only for cranes with masts of large cross section. It is particularly expensive, because it requires motor means, braking means and specific safety devices.

In addition, in the field of ladders in general, numerous more or less effective safety devices have already been proposed for climbing and lowering the ladder, as well as devices forming a working or intervention platform, which can be placed at the desired height on a ladder.

• Le dispositif n'assure pas une protection complète, c'est-à-dire à la fois latérale, inférieure et éventuellement supérieure de l'opérateur.
• L'utilisation d'un tel dispositif est particulièrement fatigante, puisque l'utilisateur doit monter à l'échelle par la seule force de ses jambes, sans pouvoir s'aider de ses bras.
• Cet inconvénient est aggravé par le fait que le dispositif ne comporte aucun moyen de compensation de son poids, lequel s'ajoute à celui de l'utilisateur.
• Le dispositif n'offre pas une sécurité véritable, au sens d'une immobilisation ferme de ce dispositif sur l'échelle, à toute hauteur; l'utilisation de la seule pression de ressorts est notablement insuffisante pour immobiliser le protecteur sur les montants de l'échelle.
• L'entraînement du dispositif le long de l'échelle, lors de la montée, se fait seulement par la tenue des poignées, ce qui impose un geste volontaire et inhabituel; une sangle entre-jambes retient l'utilisateur mais ne permet pas l'entraînement du dispositif vers le haut, lors de la montée de l'échelle.
• Le dispositif ne comporte aucun moyen facilitant son accès depuis l'extérieur, et la sortie de l'utilisateur; en particulier, il n'est prévu aucune disposition permettant à l'utilisateur, parvenu en position haute, de sortir en toute sécurité du protecteur, pour gagner un poste de conduite élevé, notamment une cabine de grue à tour qui se situerait sur le côté de l'échelle.
• Enfin, ce dispositif connu n'est pas véritablement adapté au passage d'une échelle à une autre, avec guidage continu, alors que les grues à mât télescopique ou repliable possèdent habituellement une succession d'échelles. Ainsi, la solution révélée par la demande de brevet français N° 2.495.684, au demeurant formulée de manière très succincte, s'avère non ergonomique et même totalement irréaliste, en particulier vis-à-vis du domaine spécifique d'application de la présente invention.

In particular, French patent application No. 2,495,684 discloses a sliding protector, constituted by a sort of carriage rolling along the uprights of a ladder, and provided laterally with handles gripped by the operator when the l 'ladder. This device in itself has many drawbacks, and it is neither intended nor adapted for access to a high driving position, such as a crane cabin:

• The device does not provide complete protection, that is to say at the same time lateral, bottom and possibly top of the operator.
• The use of such a device is particularly tiring, since the user must climb the ladder by the sole force of his legs, without being able to use his arms.
• This drawback is aggravated by the fact that the device does not include any means of compensating for its weight, which is added to that of the user.
• The device does not offer real security, in the sense of a firm immobilization of this device on the ladder, at any height; the use of spring pressure alone is notably insufficient to immobilize the guard on the uprights of the ladder.
• The training of the device along the ladder, during the climb, is done only by holding the handles, which requires a voluntary and unusual gesture; a crotch strap retains the user but does not allow the device to be driven upwards, when climbing the ladder.
• The device has no means facilitating its access from the outside, and the exit of the user; in particular, no arrangement allowing the user, having reached the high position, to exit the guard in complete safety, to gain a high driving position, in particular a tower crane cabin which would be located on the side of the ladder.
• Finally, this known device is not really suitable for passing from one ladder to another, with continuous guidance, whereas cranes with telescopic or folding mast usually have a succession of ladders. Thus, the solution revealed by French patent application No. 2,495,684, moreover formulated very succinctly, turns out to be non-ergonomic and even completely unrealistic, in particular with regard to the specific field of application of the present invention.

French patent application N ° 2.518.519 discloses a lifting device, intended to facilitate the mounting of a crane operator on a tower crane, the device presenting itself mainly as a mobile seat, suspended on a cable, and also comprising a counterweight and possibly a drive motor.

In this known device, the seat is neither maintained nor guided on the ladder or on another part of the mast of the crane, this seat being simply suspended from the cable. Consequently, if the crane operator is uncomfortable, he can tip around the seat or even with this seat, with the additional risk of hitting the bars of the ladder or parts of the crane mast, and of hanging head below. In addition, the device is not likely to surround and protect the crane operator on all sides. This device therefore does not provide adequate protection and security, which are precisely the aims of the present invention.

Furthermore, with its mobile part limited to a single seat, the device of French patent application N ° 2.518.519 does not allow the transport of tools, documentation or any other useful object for the personnel responsible for the maintenance of the crane. Finally, this device cannot constitute a working platform for maintenance personnel.

French patent application No. 2,682,098 describes a safety device, for tower cranes and the like, which comprises a cable and a counterweight, the cable being intended to be connected, by a hook which is fixed to a belt or to a harness, with the person using the ladder. This document does not provide any protection which would accompany the person moving along the ladder and who would surround this person, and the ladder remains provided with a conventional fixed crinoline, whereas the present invention aims precisely to remove the crinoline and the disadvantages associated with it.

Mention may also be made of U.S. Patent No. 2,245,661, in which is described a harness device, movable along a ladder and used for carrying out work at height. Thus, this device constitutes a small work platform, which can be hung at the desired level on the bars of a ladder, but like the previous ones, it is not designed for secure access to a driving position located high up, in particular to the cabin of a tower crane.

The object of the present invention is to remedy the drawbacks set out above, by providing a method and a device for secure access to a high driving position, in particular to the cabin of a tower crane, which limit the effects of wind to increase the mechanical resistance and the range of autonomy of the crane, and which facilitate the folding of the crane for transport on the road, while ensuring optimal ergonomics and safety, both during the ascent and the lowering the mast only when the crane operator goes from the ladder to the cabin, and vice versa.

To this end, a method is essentially proposed for secure access to a high driving position, in particular on a tower crane, accessible by a mast or the like in one or more parts laterally equipped with one or more ladders of access to a driving position or cabin, method which according to the invention consists in using an individual protection device, mobile along the mast, maintained and guided on the ladder or successively on the ladders and driven along the mast, by through a harness resting on the crane operator's shoulders or a harness supporting the crane operator, on the path of this crane operator when climbing along the ladder or ladders to the cabin, and vice versa during from his descent from the cabin.

As is easily understood, the fact of using a mobile individual protection device accompanying the crane operator during his ascent or descent, between the ground and the cabin, makes it possible to eliminate the traditional fixed crinolines, therefore to limit the effects of wind, thanks to the significant reduction of surfaces exposed to the wind. The removal of crinolines also facilitates folding and transporting of the crane, and makes it much less vulnerable; it will be noted that, for the transport of the crane, the individual protection device is brought back to the base of the mast of the crane, or even removed from the crane. This device mainly provides permanent protection, as close as possible to the crane operator, and it can also provide, at any time and in any position along the mast, a function of rest or intervention platform.

As indicated above, the personal protective device is driven along the mast, by means of a harness resting on the shoulders of the crane operator, or of a harness supporting the crane operator. In all cases, the personal protective device can thus accompany the crane operator, during the climb or the Descent of the ladder, which is always done in a normal gesture, the crane operator placing his hands and feet on the bars of the ladder.

The device, according to the invention, for secure access to an elevated driving position, in particular on a tower crane, for implementing the method defined above, comprises a personal protective nacelle, accessible from the outside , inside which the crane operator can stand upright, the nacelle being provided with means for holding and guiding on the ladder (s) of the mast, and with a harness or harness for his training by the crane operator, the device comprising still means for compensating for the weight of the nacelle and means for immobilizing said nacelle.

Advantageously, the protective nacelle is presented as a rigid closed but perforated structure, composed of horizontal arches joined by vertical rails, of a floor located at its base and having a function of rest and intervention platform, and, possibly a protective roof in its upper part. Thus, this structure provides lateral, dorsal, lower and, where appropriate, superior protection. The floor also allows the safe installation of tools or documentation necessary for maintenance personnel.

According to an additional characteristic, the protective nacelle is provided with a side access door, opening inwards, and an emergency hatch formed in the floor. The side door facilitates the crane operator's access to the interior of the platform, when it is in the low position, and above all, in the high position of the platform, the crane operator can safely pass the platform towards the cabin, and vice versa. The fact that the door opens only towards the interior of the nacelle avoids any risk of falling due to a push against this door, or an untimely opening whatever the cause, while the nacelle is located at an intermediate height.

According to another characteristic, the means for holding and guiding the protective nacelle consist of pairs of rollers mounted in lines respectively on sleepers symmetrically fixed on either side of the nacelle, on the one hand, at its lower part or floor and, on the other hand, at an intermediate level between the lower part or floor and the upper part of the nacelle, the pairs of rollers bearing continuously on the uprights of the ladder or scales of the mast.

According to an additional characteristic, in the case of a mast with successive elements, of sections which are different from each other, carrying respective scales, provision is made for free spaces, substantially equal to the thickness of the uprights of the scales of the mast, are provided between the different lines of rollers, in correspondence with the different positions of the ladders on the mast elements. The passage of the protective basket, from one scale to the next, is thus carried out without discontinuity, whatever the number of scales.

In a particular embodiment, the means for compensating for the weight of the protective nacelle consist of a winch, equipped with a torque motor, fixed to the top of the mast, the cable of the winch descending directly above the nacelle and being fixed at a point located at the top of said nacelle. These means make it possible to compensate for the weight of the nacelle driven by the crane operator, so that the effort to be provided by the crane operator during the climb is practically not increased. In addition, by the appropriate adjustment of the effort to compensate for the weight of the nacelle, it is ensured that the nacelle is effectively driven by the crane operator, either by through the harness, or through the harness.

As for the means of immobilization of the protective nacelle, in a particular embodiment, these consist of a reel provided with an anti-fall device operating by inertia, known per se, fixed to the top of the mast substantially at plumb with the nacelle, the cable of the reel being fixed at a point located at the upper part of said nacelle. Such means immediately stop any fall of the nacelle, therefore of the crane operator who is inside.

The device defined above is more particularly applicable to the access to a cabin of an automated assembly tower crane, with telescopic or folding mast composed of successive mast elements carrying respective scales, on which the nacelle is maintained and guided. protection. It can be, among other things, a tower crane whose cabin, to which this device gives access, is itself mobile along the crane mast, and in particular guided on the same scales as the nacelle of protection. Such a cabin can be immobilized at any intermediate height, and it will be noted that the device according to the invention allows in this case access to the cabin, whatever its level of immobilization.

Still more particularly, the invention is applicable to a tower crane with telescopic mast in which the ladders, other than the scale of the lower mast element, are rigidly fixed, only by their upper part, at the top of the corresponding mast element, the ladders being offset transversely with respect to each other and being provided with a middle rail for holding and guiding the lower end of the ladder of the immediately upper mast element, this end being equipped with a rolling and / or sliding means cooperating with the rail. These provisions allow the mast to be telescoped with its ladders, and ensure that the ladders are kept in position, to allow the passage of the protective nacelle from one ladder to the next, during its ascent, or to the previous, during its descent.

• Figure 1 est une vue latérale d'ensemble, à l'état monté, d'une grue à tour à laquelle s'applique le procédé selon l'invention, la nacelle de protection du dispositif d'accès à la cabine occupant sa position basse;
• Figure 2 est une vue arrière d'ensemble de la même grue, correspondant à la figure 1;
• Figure 3 est une vue latérale d'ensemble de la même grue, la nacelle de protection occupant sa position haute;
• Figure 4 est une vue arrière de la même grue, correspondant à la figure 3;
• Figure 5 est une vue latérale de détail de la nacelle de protection, guidée sur une échelle et associée à des moyens de compensation de son poids et d'immobilisation, dans une première forme de réalisation;
• Figure 6 est une vue en plan par dessus de la nacelle de protection selon la figure 5, montrant sa disposition par rapport à la cabine de la grue;
• Figure 7 est une vue latérale de détail de la nacelle de protection, guidée sur une échelle et associée à des moyens de compensation de son poids et d'immobilisation, dans une seconde forme de réalisation;
• Figure 8 est une vue arrière de détail de la nacelle de figure 7, montrant sa disposition par rapport à la cabine de la grue;
• Figure 9 est une vue en plan par dessus de cette nacelle, correspondant à la figure 8;
• Figure 10 est une vue latérale partielle du mât, et des échelles associées, d'une grue à tour à laquelle est appliquée l'invention;
• Figure 11 est une vue en plan par dessus de l'ensemble d'échelles équipant le mât de cette grue.

In any case, the invention will be better understood with the aid of the description which follows, with reference to the appended diagrammatic drawing which, by way of example, illustrates modes of implementation of this method for secure access to a high operator position, and represents embodiments of the associated device, in the case of application to a tower crane:

• Figure 1 is an overall side view, in the assembled state, of a tower crane to which the method according to the invention applies, the protection nacelle of the access device to the cabin occupying its low position ;
• Figure 2 is an overall rear view of the same crane, corresponding to Figure 1;
• Figure 3 is an overall side view of the same crane, the protective nacelle occupying its high position;
• Figure 4 is a rear view of the same crane, corresponding to Figure 3;
• Figure 5 is a detail side view of the protective nacelle, guided on a ladder and associated with means of compensation for its weight and immobilization, in a first embodiment;
• Figure 6 is a plan view from above of the protective nacelle according to Figure 5, showing its arrangement relative to the crane cabin;
• Figure 7 is a detail side view of the protective nacelle, guided on a ladder and associated with means of compensation for its weight and immobilization, in a second embodiment;
• Figure 8 is a rear detail view of the nacelle of Figure 7, showing its arrangement relative to the cabin of the crane;
• Figure 9 is a plan view from above of this nacelle, corresponding to Figure 8;
• Figure 10 is a partial side view of the mast, and associated ladders, of a tower crane to which the invention is applied;
• Figure 11 is a plan view from above of the set of ladders fitted to the mast of this crane.

The tower crane, shown as a whole in FIGS. 1 to 4, comprises in known manner a fixed or rolling base chassis 1 supporting, by means of an orientation device 2 with vertical axis 3, a rotating chassis 4 which carries a mast 5. This tower crane is provided with a distributing jib 6, carried by the top of the mast 5 and kept horizontal by means of a tie rod 7, a punch 8 and a rear shroud 9 , connected to the rear of the rotating chassis 4.

In the particular case illustrated in the drawing, the mast 5 is telescopic. It consists of three successive mast elements 10, 11, 12 whose respective cross sections are different and decreasing from bottom to top, to allow telescoping. Each mast element 10, 11, 12 carries a ladder, respectively 13, 14, 15, fixed laterally to this mast element. As shown schematically in Figures 2 and 4, the scales 13, 14, 15 are offset transversely, with respect to each other; this provision will be explained below.

The crane is provided with a cabin 16, carried by the mast 5 and offset laterally with respect to this mast 5 and to the jib 6. The cabin 16 occupies in particular, when the crane is in service, a high position, at the top of the mast 5. However, it should be noted that this cabin 16 can also be immobilized at an intermediate height on the mast 5, when the crane is in service, or be lowered at the foot of the mast 5 for folding the crane, said cabin 16 being guided on the ladders 13, 14, 15.

According to the invention, the crane is equipped with a device for access to the cabin 16, placed at the chosen height, this device allowing the crane operator to safely access the cabin 16, from the ground. The device generally comprises a protective nacelle 17 inside which the crane operator can stand, means 18 for compensating for the weight of the nacelle 17, and means 19 for immobilizing said nacelle 17.

As shown in Figures 5 and 6, relating to a first embodiment of this device, the protective nacelle 17 has a rigid structure, closed but perforated, composed of horizontal arches 20 joined by vertical rails 21, a floor 22 located at the base of the structure, and a harness 23 located in the upper half of this structure.

The protective nacelle 17 is equipped, at the level of the floor 22 and at an intermediate level between the floor 22 and the harness 23, of two superimposed pairs of horizontal crosspieces 24 and 25, fixed symmetrically on either side of the nacelle 17 The crosspieces 24 and 25 respectively carry rollers 26 and 27, with horizontal axes, spaced horizontally from the thickness e of the uprights 28 of the scales 13, 14, 15 of the mast 5. In the example illustrated, each crosspiece 24 or 25 carries four rollers 26 or 27 mounted in lines, providing between them three identical free spaces of value e, corresponding respectively to the passage of the uprights 28, offset horizontally, of the different scales 13, 14, 15.

The protective nacelle 17 is also provided with a lateral access door 29, articulated around a vertical axis 30 and opening towards the interior of the nacelle (see FIG. 6), and with an emergency hatch 31 formed in the floor 22.

The upper part of the nacelle 17, indicated at 32, possibly forms a protective roof, not shown in detail.

The compensation means 18 for the weight of the nacelle 17 consist, in the examples considered, of a winch 33, equipped with a torque motor, the cable 34 of which is fixed, at an attachment point 35, to the upper part 32 of the nacelle 17. The winch 33 is fixed to the top of the mast 5; it can in particular be supported by the platform 36 of the crane lifting winch.

The immobilization means 19 of the protective nacelle 17 consist, for their part, of a reel 37 unwinding or automatically winding a cable 38 which is fixed, at an attachment point 39, to the upper part 32 of the nacelle 17 The reel 37 is provided with an anti-fall device operating by inertia; it can also be provided with a control cable, provided for manual control. This reel 37 is fixed to the top of the mast 5, and it can in particular be supported by the platform 36 of the crane lifting winch.

The immobilization means 19 previously described allow immobilization of the protective nacelle 17 at any intermediate height. These immobilization means are advantageously supplemented by means, mechanical or electro-mechanical, of automatic locking of the nacelle 17 in the low position and in the high position, with manual unlocking.

The operation of the device described above, for access to the cabin 16 of the crane, is as follows:

At the start, as shown in FIGS. 1 and 2, the crane is in the assembled state with the cabin 16 arranged at the top of the mast 5 (the cabin 16 having been previously brought to the top of the mast, if it is a question of a cabin that can also occupy a low position). The protective nacelle 17 is in the low position, and it is located accessible from the rotating chassis 4, via a recipe platform 40.

In this configuration, the crane operator directly accesses the interior of the nacelle 17 through the side door 29; it goes into the usual position for climbing the lower ladder 13, and initiates the climbing of this ladder 13.

As soon as the first steps of the ladder 13 are climbed, the crane operator's shoulders are supported under the harness 23 of the nacelle 17. Thus, continuing to climb normally on the ladder 13, the crane operator carries with him, by the intermediate of the harness 23, the nacelle 17, the weight of which is compensated by the tractive force, directed upwards, exerted by the cable 34 of the winch 33. During this time, the cable 38 belonging to the immobilizing means 19 s' rolls up automatically on the reel 37, to ensure the safety of movement of the nacelle 17 throughout its ascent, accompanying that of the crane operator, along the mast 5.

The nacelle 17 firstly moves along the lower element 10 of the mast 5, the first pairs of rollers 26 and 27 ensuring its guidance and its maintenance on the uprights 28 of the ladder 13 associated with this lower element 10 When the nacelle 17 driven by the crane operator crosses the passage from the lower mast element 10 to the intermediate mast element 11, the second pairs of rollers 26 and 27 take over from the first pairs of rollers, ensuring continuity guiding and holding on the uprights 28 of the following ladder 14. Likewise, when the nacelle 17 which has reached higher crosses the passage from the intermediate mast element 11 to the upper mast element 12, the third pairs of rollers 26 and 27 intervene to ensure the continuity of the guidance and the maintenance on the uprights 28 of the last ladder 15. The nacelle 17 thus accompanies the crane operator, throughout the ascent of the mast 5, ensuring lateral and dorsal protection, an intermediate position of the nacelle 17 being indicated in FIG. 2.

Finally, the nacelle 17 arrives, with the crane operator, in its high position located at the level of the cabin 16 - see Figures 3 and 4. The nacelle 17 locks automatically in this high position, and the crane operator accesses directly inside the cabin 16, the door of which comes in correspondence with the side door 29 of the nacelle 17, the relative arrangement of the cabin 16 and of the nacelle 17 also appearing clearly in FIG. 6.

Conversely, the crane operator descends from the crane with the protective nacelle 17, after having manually unlocked said nacelle.

To ensure correct operation, uphill and downhill, the harness 23 must permanently exert a downward and substantially constant force, of the order of a few kilograms, on the shoulders of the crane operator. The value of this force is adjusted by means of the torque motor of the winch 33 to compensate for the weight of the nacelle 17. In other words, the self-weight of this nacelle 17 need not be fully compensated, so that the harness 23 remains supported on the crane operator's shoulders.

The previously described device allows the crane operator, by locking the nacelle 17, to rest at any time during his ascent or descent path along the mast 5, by placing himself on the floor 22. This device also allows the crane operator to intervene at any intermediate point in the path between the ground and the cabin 16, the floor 22 of the nacelle 17 then acting as a working platform. During such interventions, the harness 23 can be retracted so as not to hinder the crane operator in his movements.

In the event of discomfort of the crane operator, or of a technical incident involving the blocking of the protective basket 17 at a point remote from the ground, rescue or maintenance personnel can intervene to rescue the crane operator, using the ladders 13, 14 , 15 from the mast 5 and individual safety equipment, access to the interior of the nacelle 17 being made possible in particular by the emergency hatch 31.

Figures 7 to 9 show another embodiment of the protective nacelle 17, in which the unmodified elements (with respect to the first embodiment) are designated by the same references, and will not be described again. In this second embodiment, the harness is replaced by a harness 41, composed of one or more straps moored to the rigid structure of the nacelle 17. Unlike the previous embodiment, the compensation means 18 exert here on the nacelle an upwardly directed effort which is greater than the self-weight of the nacelle 17, so that the harness 41 permanently supports the crane operator. It is thus guaranteed that the nacelle 17 accompanies the crane operator during the raising or lowering of the mast 5.

Figures 10 and 11 show details of the scales 13, 14, 15 respectively associated with the three elements 10, 11, 12 of the telescopic mast 5. The scale 13 of the lower mast element 10 is located closest to the central axis 3 of the mast 5. The scale 14 of the intermediate mast element 11 is offset towards the outside, with respect to the previous scale 13. The scale 15 of the upper mast element 12 is itself even offset towards the outside, compared to the previous scale 14. The two scales 14 and 15, other than the scale 13 of the lower mast element 10, are rigidly fixed only by their upper part at the top of the corresponding mast element 11 or 12, via a pair horizontal spacers 42. In addition, the lower ends of the two scales 14 and 15 are held and guided, respectively, on the two scales 13 and 14.

To this end, each scale 13, 14, 15 comprises, over its entire height, a vertical median rail 43, of "T" section. The lower end of the upper ladder 15 is provided with a holding and guide shoe 44, engaged on the middle rail 43 of the intermediate ladder 14. Likewise, the lower end of this intermediate ladder 14 is provided a holding and guiding pad 45, engaged on the median rail of the lower ladder 13.

These provisions allow the relative sliding of the three ladders 13, 14, 15, accompanying the telescoping of the mast 5. In addition, in relation to the device object of the present invention, they ensure the holding in position of the ladders 13, 14, 15 with the required horizontal spacing, corresponding to the diameter of the rollers 26 and 27, between their respective uprights 28, which is necessary for the passage of the protective nacelle 17, from one scale to the next or to the previous one, during the ascent or descent of the crane operator.

We would not depart from the scope of the invention as defined by the claims by applying the same process to access to driving positions, whether or not in the form of a cabin, always situated at a height, but belonging to other lifting and handling devices, such as port cranes, gantry cranes, overhead cranes, etc., always provided with at least one mast or the like, also referred to as "leg" or "palée" , fitted laterally with one or more access ladders to the driving position. We would not depart, either, from the scope of the invention as defined by the claims by modifications of forms and constructive details, concerning the protective nacelle and its guidance along the mast of the crane or other lifting or handling device, or concerning the means of compensating for the weight of the nacelle and the means of immobilizing said nacelle, or also concerning the ladders with their holding means and guide, where the sliding pads can be replaced or supplemented by rolling means.

Claims (11)

Method for secure access to a high driving position, in particular on a tower crane, accessible by a mast or the like (5) in one or more parts (10, 11, 12) fitted laterally with one or more ladders ( 13, 14, 15) of access to a driving position or cabin (16), characterized in that it consists in using an individual protection device (17, 18, 19), movable along the mast (5) , maintained and guided on the ladder or successively on the ladders (13, 14, 15) and driven along the mast (5), by means of a harness (23) resting on the shoulders of the crane operator or a harness (41) supporting the crane operator, on the path of this crane operator when climbing along the ladder or ladders (13, 14, 15) up to the cabin (16), and vice versa during his descent from the cabin (16). Device for secure access to an elevated driving position, in particular on a tower crane, for implementing the method according to claim 1, characterized in that it comprises an individual protection nacelle (17), accessible from outside, inside of which the crane operator can stand, the basket (17) being provided with holding and guiding means (24, 25, 26, 27) on the ladder (s) (13, 14, 15) of the mast (5), and of a harness (23) or harness (41) for its training by the crane operator, the device further comprising means of compensation (18) for the weight of the nacelle (17) and means immobilization (19) of said nacelle (17). Device for secure access to a high driving position, according to claim 2, characterized in that the protective nacelle (17) is presented as a rigid closed but perforated structure, composed of horizontal arches (20) joined by vertical rails (21), a floor (22) located at its base and having a function of rest or intervention platform and, possibly a protective roof in its upper part (32). Device for secure access to a high driving position, according to claim 3, characterized in that the protective nacelle (17) is provided with a side access door (29), opening inwards , and an emergency hatch (31) formed in the floor (22). Device for secure access to an elevated driving position, according to any one of claims 2 to 4, characterized in that the means for holding and guiding the protective nacelle (17) consist of pairs of rollers ( 26, 27) mounted in lines respectively on crosspieces (24, 25), symmetrically fixed on either side of the nacelle (17), on the one hand, at its lower part or floor (22) and, on the other hand, at an intermediate level between the lower part or floor (22) and the upper part (32) of the nacelle (17), the pairs of rollers (26, 27) resting continuously on the uprights (28) the ladder (s) (13, 14, 15) of the mast (5). Device for secure access to an elevated driving position, according to claim 5, characterized in that free spaces, substantially equal to the thickness (e) of the uprights (28) of the ladders (13, 14, 15) of the mast, are formed between the different lines of rollers (26, 27), in correspondence with the different positions of the ladders (13, 14, 15) on mast elements (10, 11, 12) successive, of different sections each others. Device for secure access to an elevated driving position, according to any one of claims 2 to 6, characterized in that the compensation means (18) for the weight of the protective nacelle (17) consist of a winch ( 33), fitted with a torque motor, fixed to the top of the mast (5), the cable (34) of the winch (33) descending directly above the nacelle (17) and being fixed at a point (35) located at the upper part (32) of said nacelle (17). Device for secure access to a high driving position, according to any one of claims 2 to 7, characterized in that the immobilization means (19) of the protective nacelle (17) consist of a reel (37 ) provided with an anti-fall device operating by inertia, fixed to the top of the mast (5) substantially in line with the nacelle (17), the cable (38) of the reel (37) being fixed at a point (39) located at the upper part (32) of said nacelle (17). Device for secure access to an elevated driving position, according to any one of claims 2 to 8, characterized by its application to access to a cabin (16) of an automated tower crane, with mast telescopic or foldable (5) composed of successive mast elements (10, 11, 12) carrying respective scales (13, 14, 15), on which the protective nacelle (17) is held and guided. Device for secure access to a high driving position on a tower crane, according to claim 9, characterized in that the cabin (16), to which this device gives access, is itself movable along the mast ( 5) of the crane, and in particular guided on the same scales (13, 14, 15) as the protective nacelle (17). Device for secure access to a high driving position, on a tower crane with telescopic mast according to claim 9 or 10, characterized in that the ladders (14, 15), other than the ladder (13) of the 'lower mast element (10), are rigidly fixed (at 42) only by their upper part at the top of the corresponding mast element (11, 12), the scales (13, 14, 15) being offset transversely compared to the others and being provided with a middle rail (43) for holding and guiding the lower end of the ladder (14, 15) of the immediately upper mast element (11, 12), this lower end being fitted with rolling and / or sliding means (44, 45) cooperating with the rail (43).

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