EP0612899B1 - Scaffolding-platform and method for erecting scaffolds with such platform - Google Patents

Abstract

The scaffolding platform (7), of rectangular overall shape, includes retractable hooks (10) at its ends towards its four corners, these hooks being mounted so that they can pivot about horizontal pins (13). The pivoting hooks (10) lock onto the horizontal bars (6) of the ladder elements (3) belonging to the vertical structure of the scaffolding, but these hooks (10) retract into the overall size of the platform (7) when the platform is being lifted up. The platform (7) is hoisted up and lowered by means of hauling cables or ropes (16, 17) attached (at 15', 15'') to the hooks (10) and which can be operated from the ground or from a winch borne by the platform (7). This device applies more particularly to moving scaffolding. <IMAGE>

Description

The present invention relates to a scaffolding plate, more particularly a rolling scaffolding plate, the scaffolding plate of generally rectangular shape comprising at its opposite ends means for hooking to horizontal bars belonging to vertical scales, making them - same part of the vertical structure of a scaffolding, the hooking means comprising in total four hooks mounted pivoting, at the ends of the plate, around axes which, in the mounted position of the plate are substantially horizontal and which extend parallel to the rungs of the ladders, the hooks normally projecting at the ends of the tray but being erasable by pivoting in the space requirement of the tray, in particular when the ladder rungs pass, these pivoting hooks having in their upper part a ramp configuration allowing them to automatically erase when passing a bar, then re position automatically above this bar, during a lifting movement of the plate. The invention also relates to a scaffolding mounting system using this scaffolding plate. This invention relates, more particularly, to the field of rolling scaffolding.

A rolling scaffold, in steel or aluminum, generally comprises a vertical structure equipped with work or access platforms. The vertical structure is fixed on a mobile base structure, provided with wheels.

The vertical structure of rectangular horizontal section includes two opposite scales and connected to each other by crossbars or diagonals. These scales generally correspond to the short sides of the rectangular horizontal section, while the braces or diagonals correspond to the long sides of this section.

• elles participent à la résistance mécanique de la structure verticale ;
• elles permettent l'accès aux planchers de travail ou d'accès ;
• elles permettent le positionnement et le réglage en hauteur des plateaux.

The tubular ladders are essentially made up of vertical uprights and horizontal bars regularly arranged along the uprights. These scales fulfill the following functions:

• they participate in the mechanical resistance of the vertical structure;
• they allow access to work or access floors;
• they allow positioning and height adjustment of the trays.

The work or access trays are arranged regularly along the structure. They include devices allowing the attachment of these plates on the bars of the ladders.

The creation of the trays remains simple. A metal frame ensures the mechanical resistance of the tray and the plinth function, and a plywood panel inserted in the frame provides the floor function.

One of the major difficulties when assembling rolling scaffolding is the installation of work or access platforms. A procedure commonly used consists in using two ropes which are attached to each end of the plates, then placing this plate outside the vertical structure, parallel to the long side of the rectangle formed by the horizontal section of this vertical structure. After climbing to the ends of the ladders, two operators can, using the ropes, hoist the platform on the outside of the vertical structure to the desired level. The tray is temporarily held at this level by the cords fixed to the structure, then in a more or less awkward manner, the tray is manually slid by the operators inside the structure to be hung in position there; finally, railings are put in place on the longitudinal sides of the tray.

This operation remains long and dangerous since the operators are placed outside the vertical structure, held on ladders only by their legs, in order to have their arms to pull the tray.

A second difficulty lies in adjusting the level of the tray. Indeed, for height positioning needs to work in the ceiling, it is often necessary to vertically move the tray of a bar or two. This operation requires two people, because it is necessary to lift the plate to release its hooks from the bars, tilt the plate so that the hooks escape these bars during the vertical adjustment movement, and reposition it horizontally often by engaging the plate between bars. This operation is not only dangerous but also difficult to perform, because the operators must stand outside the ladders, while holding the tray inside the vertical structure.

A third difficulty lies in the installation of scales and diagonals. These, according to a known operating mode, are hoisted to the top of the structure using ropes or manually, the ladder nesting operation being possible only if the operator releases his body outside of the structure, while being attached to the structure with its legs. It is a dangerous operation. Another method consists in placing the trays approximately every two meters and in constructing the scaffolding from said trays. This operation remains long and requires a large number of trays, which is not always advantageous, especially for great heights where you only need the last tray to work.

As can therefore be seen, a large part of the difficulties currently encountered results from the fact that the plates cannot be engaged or moved, except inside the vertical scaffolding structure, between the two opposite scales, only if these plates are inclined, because the distance between their hooks is equal to the distance between the two scales, therefore at the distance between the corresponding bars of these scales.

To simplify and rationalize the mounting operations of the scaffolding plates, scaffolding plates have already been proposed provided, at their ends, with hooks mounted pivoting about substantially horizontal axes, which in the assembled position of the plate s' extend parallel to the bars of the ladders, so that the hooks can be erased by pivoting in the space requirement of the tray. These pivoting hooks have in their upper part a ramp configuration allowing them to automatically disappear when a bar passes, then to automatically reposition themselves above this bar, during a lifting movement of the plate. In this regard, reference may be made to documents FR-A-2231235 and FR-A-2261387, serving here as a basis for the preamble of claim 1.

These known devices with pivoting hooks, which act like pawls, bring a certain mechanization but retain insufficiencies. Thus, in the case of document FR-A-2231235, there are two hooks in total (only one hook at each end of the plate), and they occupy median positions, making the stability of the plate uncertain. In addition, these hooks are manually actuated by operators, who must again place themselves in a dangerous position on the ladders to change the level of the platform.

In the case of document FR-A-2261387, the hooks totaling eight constitute a complex device, and these hooks are only safety hooks intended to act in the event of breakage of the cable. lifting used to move the plate. Again, the actuation of the hooks must be done manually, by an operator located on site.

Thus, the devices of the documents discussed above retain the disadvantage of requiring personnel interventions, at height and often in dangerous positions.

The present invention aims to avoid these drawbacks by providing a scaffolding platform with pivoting hooks which can be maneuvered more simply, more quickly and more safely by the personnel, in particular from the ground or from this platform itself, which allows to consider a complete mechanized system of scaffolding assembly.

To this end, in the scaffolding plate which is the subject of the invention, of the type specified in the introduction, said pivoting hooks, situated outside the longitudinal sides of the frame of the plate, respectively near its four angles, comprise, towards the two ends, respectively inner and outer, of their upper part, mooring points for a rope or a traction cable used for hoisting or lowering this platform inside the vertical structure of the scaffolding, the mooring point used tends to align with the vertical of the pivot axes when the rope or pull cable is stretched.

Thus, the scaffolding plate according to the invention offers the advantage of being able to be hoisted or lowered, inside the vertical structure of the scaffolding, by means of ropes or traction cables linked to the pivoting hooks in judiciously chosen mooring points. Unlike the previously known embodiments, in the invention the hooks not only ensure the connection between the scaffolding plate and a ladder bar, when this plate is brought to the level desired, but still these hooks are an integral part of the traction chain, allowing the platform to be raised to a higher level or lowered. The action on the hooks via cables or ropes can be exerted, alternately, at one end of the platform and at its other end (the platform taking intermediate inclined positions), so that only one operator can climb or descend the platform, in particular by operating at a distance from the ground, in complete safety. The invention is therefore essentially based on the inventive idea of connecting the cables or traction cords to the plate by means of the pivoting hooks, which is by no means the case in the state of the art as illustrated by the aforementioned document FR-A-2261387. Furthermore, the hooks being arranged at the four angles of the scaffolding plate, this plate is hung in a stable manner, and resistant to loads, on the vertical scales of the structure of the scaffolding.

According to one embodiment of the invention, the two pivoting hooks located on either side of the scaffolding plate, at the same end of said plate, are connected to each other by a cross member, ensuring synchronization of their movements.

The present invention also provides a scaffolding mounting system, in particular a rolling scaffolding, using the swivel hook plate previously defined, this mounting system comprising at least two ropes or traction cables whose ends are attached to the points of mooring provided on the upper parts of said hooks, and which pass over respective return pulleys, of substantially horizontal axis, positioned towards the top of the scales of the vertical structure of the scaffolding.

According to a simple embodiment of this mounting system, the two traction cords associated respectively with the two ends of the plate scaffolding each have, in addition to their strand extending between the pivoting hooks and the corresponding return pulley, another strand extending from the corresponding return pulley to the ground. Thus, the traction on the two ropes can be exerted from the ground, or quite safely, by two operators, this to hoist a tray to the chosen level, the hooks of the tray automatically disappearing with each passage of a bar according the principle set out above. This simple and inexpensive embodiment allows the rapid assembly, adjustment and disassembly of the scaffolding platform (s).

According to a variant of this scaffolding mounting system, the two traction cables associated respectively with the two ends of the scaffolding plate each have, in addition to their strand extending between the pivoting hooks and the corresponding return pulley, another strand extending from the corresponding return pulley to a winch carried by the scaffolding plate itself. The hoisting of the platform is thus achievable by operators posted on this platform, who actuate or control the winches so as to wind the cables and thus cause the elevation of the platform, whose pivoting hooks are erased as before the passage of the bars .

This latter system, also using removable crossmembers carrying the deflection pulleys over which the two traction cables pass, allows not only the mounting of the plates, but also the mounting of the entire vertical structure of the scaffolding, with its ladders and diagonals or crosspieces, this in a fast and safe way, the tray being already initially fitted with railings along its longitudinal sides. The winches are either manual or motorized which can represent an additional advantage.

• Figure 1 est une vue en perspective d'un échafaudage roulant équipé d'un plateau et d'un système de montage conformes à la présente invention ;
• Figure 2 est une vue de face partielle de l'échafaudage de figure 1, avec indication du plateau accroché à ses échelles ;
• Figures 3 et 4 sont des vues similaires à figure 2, mais montrant le plateau d'échafaudage en cours de hissage au moyen de cordes ;
• Figure 5 est une vue similaire aux précédentes, illustrant la manoeuvre de descente de ce plateau d'échafaudage au moyen de cordes ;
• Figure 6 est une vue de face partielle d'un échafaudage en cours de montage mécanisé, avec plateau équipé de treuils ;
• Figures 7, 8 et 9 sont des vues similaires à figure 6, illustrant des phases successives du montage mécanisé de l'échafaudage.

In any case, the invention will be better understood, and other characteristics and advantages will be highlighted, using the following description, with reference to the appended schematic drawing representing, by way of examples, some forms of execution of this scaffolding platform and the scaffolding mounting system using this platform:

• Figure 1 is a perspective view of a rolling scaffold equipped with a plate and a mounting system according to the present invention;
• Figure 2 is a partial front view of the scaffolding of Figure 1, with indication of the platform attached to its scales;
• Figures 3 and 4 are views similar to Figure 2, but showing the scaffolding plate being hoisted by means of ropes;
• Figure 5 is a view similar to the previous ones, illustrating the maneuver of descent of this scaffolding plate by means of ropes;
• Figure 6 is a partial front view of a scaffolding during mechanized assembly, with platform equipped with winches;
• Figures 7, 8 and 9 are views similar to Figure 6, illustrating successive phases of the mechanized assembly of the scaffolding.

Referring first to Figures 1 to 5, it is recalled that a rolling scaffolding comprises a movable base structure 1, provided with wheels 2, which is surmounted by a vertical structure or "tower" of rectangular horizontal section. The vertical structure is made up of two opposite ladders 3, connected to each other by cross bars or diagonals 4. The ladders 3, corresponding to the short sides of the horizontal section of the scaffolding, each consist of two vertical tubular uprights 5, connected between them by horizontal bars 6, also tubular, arranged at regular vertical intervals. These scales 3 allow the positioning and the height adjustment of at least one work or access platform 7, the structure and mounting method of which are more particularly the object of the present invention.

The scaffolding plate 7, of generally rectangular shape, has a metal frame 8 into which is inserted a horizontal plywood panel 9, forming a floor capable of supporting people and equipment.

At each end, the plate 7 is equipped with two hooks 10, located outside the longitudinal sides of its frame 8, on either side of the plate; the plate 7 thus comprises, in total, four hooks 10 located respectively near its four angles. Each hook 10 has a general "T" shape, with an elongated arm 11 and an enlarged upper part 12.

The lower end of the arm 11 of each hook 10 is pivotally mounted about a horizontal axis 13, linked to the frame 8 of the plate 7 and parallel to the short sides of this frame. The upper part 12 of the hook 10, attached to the upper end of the arm 11, forms on its side facing the outside of the plate 7 a hooking spout, designed to cooperate with a horizontal bar 6. Still on the outside, the upper part 12 of the hook 10 also has, above the hooking beak, an inclined or curved edge 14, forming a ramp also intended to cooperate with the bars 6, with a view to erasing the hook 10. Points 15 'and 15' 'mooring, for a rope or a traction cable, are provided towards the two ends, respectively inner and outer, of the upper part 12 of each pivoting hook 10.

Thus, the scaffolding plate 7 can be moved, in the direction of its hoisting or its descent, at the by means of two traction cords 16 and 17, which pass over respective return pulleys 18 and 19 with a horizontal axis mounted, respectively, at the top of the two opposite scales 3 as shown in FIG. 1, and as also shown, more schematically, Figures 2 to 5. Each rope 16 or 17 has a first strand, which is subdivided into two end parts 20 intended to be moored respectively at points 15 'and 15''of the two hooks 10 at the same end of the plate 7. The other strand of each rope 16 or 17 extends from the corresponding return pulley 18 or 19 to the ground, and can thus be actuated by an operator posted on the ground.

As shown in Figures 1 and 2, when the scaffolding plate 7 is in place at the desired level, its four hooks 10 cooperate, by their hooking spouts, with two bars 6 corresponding, that is to say located facing each other at the same level, which belong respectively to the two scales 3. All the hooks 10 then occupy a position pivoted outwards.

To hoist the plate 7, either during its initial installation, or on the occasion of a subsequent adjustment, the two traction cords 16 and 17 are attached, by their end portions 20, to the mooring points 15 ' located on the inner side of the upper parts 12 of the hooks 10.

When tensile forces are exerted on the cords 16 and 17, as indicated by arrows F, the mooring points 15 ′ and the pivot axes 13 of the hooks 10 tend to align on the same vertical, the beak of each hook 10 coming to be placed in the space located between two consecutive bars 6 - see FIG. 3.

During the upward movement of the plate 7, the upper part 12 of each hook 10 comes into contact at a given moment, by its edge 14 forming a ramp, with a bar 6. The cooperation of the bar 6 and the ramp 14 repels the hook 10 inward, this hook pivoting about its axis 13 as shown in FIG. 4. As soon as the bar 6 is crossed, under the force of the pull of the rope 16 or 17 and the misalignment of the mooring point 15 'relative to the vertical of axis 13, the hook 10 automatically returns to position in the space between two consecutive bars 6 (return to the position of Figure 3).

The two ropes 16 and 17 being pulled in a synchronized manner, by two operators posted on the ground on either side of the scaffolding, the plate 7 can thus be hoisted inside the vertical structure, crossing without difficulty all the bars 6 encountered, and while remaining horizontal, the length L of this plate 7 being less than the center distance E of the two scales 3.

When the plate 7, thus hoisted, reaches the desired level of work, it is enough to release the traction exerted on each rope 16 or 17 so that the four pivoting hooks 10 are automatically positioned on two corresponding bars 6 (refer again to Figure 2).

To lower the scaffolding plate 7, in order to bring it back to the ground, the two ropes 16 and 17 are attached, by their end portions 20, to the mooring points 15 '' located on the outside of the upper parts 12 of the hooks 10 - see Figure 5. The mooring points 15 '' then tend to align with the vertical of the hinge pin 13, this for each hook 10. The hooking lugs of the four hooks 10 are thus brought back from the bars 6 of the ladders 3, these hooks 10 being kept erased in the space taken up by the plate 7. The two ropes 16 and 17 being actuated in a suitable direction indicated by arrows G, still by operators posted on the ground, the plate 7 can thus be lowered without encountering any obstacle, in particular without hitting the bars 6.

For good synchronization of the movements of the hooks, and possible manual operation of the latter, the two pivoting hooks 10 located at the same end of the scaffolding plate 7 are connected to each other by a cross member 21, joining by example the respective upper parts 12 of the two hooks 10 passing over the frame 8 of the plate 7 (see Figure 2).

The hoisting, lowering and adjustment operations, described above and illustrated in the drawing for a single scaffolding plate 7, can be repeated for one or more other plates of identical structure, brought to other levels.

In a more sophisticated mode of use, the scaffolding plate 7, produced as described above with four pivoting hooks 10, allows the mechanized mounting of this plate 7 itself, ladders 3 and diagonals 4. As shown in Figure 6, the plate 7 is initially equipped with its longitudinal railings 22, and on this plate 7 are fixed two winches 23 and 24, positioned respectively towards its two ends. The two winches 23 and 24 are here manual winches, each provided with a crank and which can thus be actuated by operators standing on the floor 9 of the plate 7. On this plate 7 are also stored ladder elements 3 and diagonals 4, the mounting of which remains to be carried out.

A first traction cable 16 connects the mooring points provided on the two hooks 10, mounted at one end of the plate 7, to the first winch 23 placed towards the same end, passing over a deflection pulley 18 carried by a cross-member 25 removably mounted at the top of the last ladder element 3 located on the corresponding side. Symmetrically, a second cable 17 connects the mooring points provided on the other two hooks 10, mounted at the opposite end of the plate 7, to the second winch 24 placed towards this end, passing on a return pulley 19 carried by a cross member 26 removably mounted at the top of the last ladder element 3 located on the corresponding side.

Since the plate 7 is initially located at a certain level, towards the base of the last ladder elements 3 in place (starting position in FIG. 6), the operators wind the two cables 16 and 17 synchronously using the respective winches 23 and 24. The plate 7 is thus hoisted to the top of the ladder elements 3, as shown in FIG. 7, the hooks 10 of the plate 7 disappearing as each bar 6 encountered, in the manner described above. .

By then initiating a downward movement, the plate 7 is locked on two corresponding bars 6 by its four hooks 10. After having relaxed the cables 16 and 17, the operators can remove the cross members 25 and 26 supporting the respective pulleys 18 and 19.

As shown in Figure 8, two new scale elements 3 'and 3' 'are then added above the scale elements 3 already previously in place and additional 4' diagonals are put in place between the new elements d 'scales 3' and 3 '', so as to reconstitute a new module of the vertical structure of the scaffolding.

The two crosspieces 25 and 26 are put back in place at the respective vertices of the new scale elements 3 'and 3' ', and as illustrated in FIG. 9 the operators can then perform a new sequence identical to that previously described, namely : elevation of the platform 7 using the winches 23 and 24, locking of the platform 7 on the tops of the new ladder elements 3 'and 3' ', and disassembly of the crosspieces 25 and 26, and so on ...

As is easily understood, the scaffolding plate 7 previously described, and the scaffolding assembly which results, are applicable not only to new scaffolding remaining to be created, but also to existing rolling scaffolding, since the implementation of the invention requires no modification of the vertical structure (3 and diagonal scales 4) scaffolding.

• en modifiant les formes de détail des crochets pivotants du plateau d'échafaudage ;
• en prévoyant sur les crochets des dispositions complémentaires, telles qu'un organe de sécurité améliorant le verrouillage de ces crochets sur les barreaux des échelles ;
• en remplaçant les treuils manuels, prévus dans la dernière forme d'exécution décrite (figures 6 à 9), par des treuils motorisés, notamment des treuils électriques, ces modifications restant toutefois dans le cadre des revendications.

We would not depart from the scope of the present invention:

• by modifying the detail forms of the swivel hooks of the scaffolding plate;
• by providing additional hooks on the hooks, such as a safety device improving the locking of these hooks on the bars of the ladders;
• by replacing the manual winches, provided in the last embodiment described (Figures 6 to 9), by motorized winches, in particular electric winches, these modifications however remaining within the scope of the claims.

Claims (9)

1. Scaffold platform, particularly a mobile-scaffold platform, the scaffold platform (7), rectangular in shape overall, having at its opposite ends means (10) for hooking onto horizontal bars (6) belonging to vertical ladders (3), themselves forming part of the vertical structure of a scaffold, the hooking-on means comprising in total four hooks (10) mounted so as to pivot, at the ends of the platform (6), about pins (13) which, in the mounted position of the platform, are substantially horizontal and extend parallel to the bars (6) on the ladders (3), the hooks (10) normally projecting at the ends of the platform (7) but being retractable by pivoting within the overall dimensions of the platform (7), notably when the bars (6) on the ladders (3) pass, these pivoting hooks (10) having in their top part (12) a slope configuration (14) enabling them to retract automatically when a bar (6) passes, and then to reposition themselves automatically above this bar (6), during a rising movement of the platform (7), characterised in that the said pivoting hooks (10), situated outside the longitudinal edges of the frame (8) of the platform (7), respectively close to its four corners, have, towards the two ends, respectively inner and outer, of their top part (12), anchoring points (15', 15") for a traction rope or cable (16, 17, 20) used for hoisting or lowering this platform (7) within the vertical structure of the scaffold, the anchoring point (15', 15") used tending to align itself on the vertical to the pivot pins (13) when the traction rope or cable (16, 17, 20) is tensioned.
2. Scaffold platform according to Claim 1, characterised in that each pivoting hook (10) has an overall T shape, with an elongate arm (11), the bottom end of which is mounted so as to pivot about a horizontal pin (13) connected to the frame (8) of the platform (7), and the top end of which is attached to a broadened top part (12) forming a hooking-on nose designed to cooperate with a bar (6), the top part (12) having, above the hooking-on nose, an inclined or curved edge (14) forming the slope designed to cooperate with the bars (6) for the purpose of the retraction of the hook (10).
3. Scaffold platform according to Claim 1 or 2, characterised in that the two pivoting hooks (10) situated on each side of the platform (7) at the same end of the latter are connected to each other by a cross member (21).
4. Scaffold platform according to Claim 3, characterised in that the cross member (21) connects the respective top parts (12) of the two pivoting hooks (10), passing above the frame (8) of the platform (7).
5. Scaffold erection system, notably for a mobile scaffold, using the scaffold platform (7) with pivoting hooks (10) according to any one of Claims 1 to 4, characterised in that it comprises at least two traction ropes or cables (16, 17), the ends (20) of which are attached to the anchoring points (15', 15") provided on the top parts (12) of the said hooks (10), and which pass over respective return pulleys (18, 19), with a substantially horizontal axis, positioned towards the top of the ladders (3) on the vertical structure of the scaffold.
6. Scaffold erection system according to Claim 5, characterised in that the two traction ropes (16, 17) associated respectively with the two ends of the scaffold platform (7) each have, in addition to their length extending between the pivoting hooks (10) and the corresponding return pulley (18, 19), another length extending from the corresponding return pulley (18, 19) as far as the ground, so as to be able to be actuated by operators stationed on the ground.
7. Scaffold erection system according to Claim 5, characterised in that the two traction cables (16, 17) associated respectively with the two ends of the scaffold platform (7) each have, in addition to their length extending between the pivoting hooks (10) and the corresponding return pulley (18, 19), another length extending from the corresponding return pulley (18, 19) as far as a winch (23, 24) carried by the scaffold platform (7) itself, so that the winches (23, 24) can be actuated or controlled by operators stationed on this platform (7).
8. Scaffold erection system according to Claim 7, characterised in that the return pulleys (18, 19) are carried by respective cross members (25, 26), mounted removably at the top of the last ladder elements (3, 3', 3").
9. Scaffold erection system according to any one of Claims 5 to 8, characterised in that each traction rope or cable (16, 17) is subdivided into two end parts (20) attached respectively to the anchoring points (15', 15") of the two hooks (10) situated at the same end of the platform (7).

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