EP0077717A2 - Telescopic lifting device for persons - Google Patents

Abstract

Device essentially characterised in that it comprises an orientable arm articulated at its base (2) on a carrying platform, the said arm consisting of a plurality of coaxial elements (3, 4, 5) which can be extended telescopically with respect to one another, are actuated relative to one another by internal actuators which are themselves telescopic, of the double-acting type, capable of being controlled in extension and retraction by the appropriate circulation (22, 23) of a pressurised fluid, the end element (5) being made integral with the turret. The invention can be applied to turret-carrying lifting devices (6), in particular for work on electrical networks. <IMAGE>

Description

The personnel elevating machines can be of several types, the main ones being: with gallows, with scissors, or telescopic, carrying at their free end a nacelle.

Telescopic type machines are more and more appreciated, because they are space-saving, slide very easily through very dense overhead electrical networks (electricity distribution network, trolley-bus network, etc.). very easy handling. Indeed, they make it possible to move in a straight line towards the objective to be reached.

These telescopic devices are currently not widespread on the market because their technology is complicated and therefore their cost is high.

Indeed, to have a "compact" machine you need at least three elements: one articulated angularly on the turret, and two extension elements.

• Un vérin hydraulique double effet est équipé à son extrémité d'un galet. Sur ce galet s'engrène une chaîne dont une extrémité est fixée au premier élément de télescope et l'autre au second élément. L'on voit ainsi que le second élément subit une extension double de celle du vérin.

Until now, these extension elements were produced in the usual manner with mobile cranes, namely:

• A double-acting hydraulic cylinder is equipped at its end with a roller. On this roller meshes a chain, one end of which is fixed to the first telescope element and the other to the second element. It can thus be seen that the second element undergoes a double extension of that of the jack.

The same principle is applied between extension elements N ° 2 and 3 etc.

L'cn thus sees that large extensions can be obtained with a relatively small stroke cylinder.

Unfortunately, you have to apply the same principle to get your arms into each other, so you need a second set of chains or steel cables to make the return.

• - Un coefficient de sécurité de 6 sur chaque câble.
• - Un câble de travail, plus un câble de sécurité, également au coefficient de 6.
• - Des diamètres de fond de gorge de poulies d'au moins 20 fois le diamètre du câble. 1
• - Un coefficient de sécurité de 5 pour chaque chaîne.
• - Une chaîne de travail, plus une chaîne de sécurité, également au coefficient de 5.
• - Pour les poulies, un diamètre au moins égal à 5 fois le pas de la chaîne.

A new complication comes from the constraints required by the new legislation which requires among other safety standards:

• - A safety factor of 6 on each cable.
• - A working cable, plus a safety cable, also with a coefficient of 6.
• - Bottom groove diameters of pulleys at least 20 times the cable diameter. 1
• - A safety factor of 5 for each chain.
• - A work chain, plus a safety chain, also with a coefficient of 5.
• - For pulleys, a diameter at least equal to 5 times the pitch of the chain.

In summary, all these constraints lead to monstrous machines in terms of weight and price, or even impracticable.

In addition, mounting all these elements inside necessarily narrow arm elements requires a lot of skill, and after assembly, the various components cannot be visited.

The object of the present invention is to overcome the aforementioned drawbacks. It relates in particular to a personnel lifting machine in which the operating flexibility and the safety are improved. This new machine also has considerable advantages in that it eliminates all the cables and chains that are found in previous machines, that it is of simple technology, that it is compact and space-saving, that it is of light weight and low price, and that finally, its assembly and maintenance are very easy.

An elevating machine according to the invention comprising an orientable arm articulated at its base on a carrying platform, is essentially characterized by the fact that said arm consists of two series of several coaxial elements fulfilling completely different and well separated functions: on the one hand, the telescopic outer tubular envelopes constituting the arm proper, and extensible with respect to each other, the envelope envelopes being the elements carrying the jib undergoing the mechanical forces of the arm and in particular the bending forces; on the other hand, internal telescopic cylinders coaxial with said envelopes to which said cylinders are subject, so that said cylinders do not have to undergo any bending stress and only have to work in pure compression or in pure traction, said cylinders being of the double-acting type, and being capable of being controlled in extension and in retraction by the appropriate circulation of a fluid under pressure, the extreme envelope being only made integral. of the turret, and not the extreme jack, the part furthest from the base is free inside said extreme casing, without interposition between the envelopes and the chain and / or roller jacks.

• La fig. 1 est une vue en élévation schématique d'un élévateur télescopique à tourelle, conforme à l'invention.
• La fig. 2 est un schéma en coupe axiale d'un bras télescopique à trois éléments selon la technique antérieure.
• La fig. 3 est un schéma d'un bras télescopique conforme à l'invention.
• Les fig. 4, 5.et 6 sont des schémas montrant les positions successives des trois éléments d'un bras télescopique conforme à l'invention dans la phase extension des vérins.
• Les fig. 7, 8 et 9 sont des vues analogues successives montrant les positions respectives des éléments du bras dans la phase rétraction des vérins.

Other features and advantages will appear on reading the description and the claims which follow, which are made with reference to the appended drawings, in which:

• Fig. 1 is a schematic elevational view of a telescopic turret lift, according to the invention.
• Fig. 2 is a diagram in axial section of a telescopic arm with three elements according to the prior art.
• Fig. 3 is a diagram of a telescopic arm according to the invention.
• Figs. 4, 5.and 6 are diagrams showing the successive positions of the three elements of a telescopic arm according to the invention in the extension phase of the jacks.
• Figs. 7, 8 and 9 are successive analogous views showing the respective positions of the elements of the arm in the retraction phase of the jacks.

In the diagram of Figure 1, we see in 1, a transporter truck on the platform of which is articulated in 2 the base element 3 of the telescopic arm from which protrude the telescopic elements 4 and 5, the end free of the element 5 carrying the turret 6.

We see at 7 the hydraulic cylinder articulated on the same platform as the element 3, said cylinder 7 being articulated elsewhere at 8 on the arm 3, to order the modification of the angular position of the telescopic arm 3, 4, 5 .

We see in Figure 2, the principle of a telescopic arm according to the prior art, using the extension of a double-acting cylinder, multiplied by a rod. The double-acting cylinder is represented by its two telescopic elements 9, 10, the element 9 being secured to the articulation 2, while the element 10 is secured to the element 4 at the point of attachment 11. The free end of the mobile part of the telescopic jack is integral with a grooved roller 12 over which passes a chain 13, the chain 13 being secured at one of its ends at 14, and at the other end at a point 15 of the internal part of the third element 5 of the telescopic arm.

In Figure 3, there is shown a telescopic arm with three successive elements 3, 4, 5, inside which has been removed any system catne and roller. The displacements of the different parts of the arm, with respect to each other, are provided both in one direction (extension) and in the other direction (retraction) by the set of successive telescopic coaxial jacks: the jack 16, 17 ensuring the respective displacement of the elements 3 , 4, while the jack 17, 18 ensures the respective displacement of the elements 4, 5. Of course, the jack member 16 is secured to the arm member 3 at 19, the jack member 17 is secured to the arm element 4 at 20, and the jack element 18 is integral with the arm element 5 at 21.

This description of principle is obviously only schematic and it can be carried out in practice according to numerous modes of execution, the common principle always remaining that of an extension or a retraction, by elements of internal cylinders in the arm, in double-acting operation.

We will describe, with reference to FIGS. 4 to 9, a particular embodiment in which it is the very bodies of the telescopic arm elements which constitute the cylinder elements, that is to say that there is identity between the arm elements 3, 4, 5 and the elements of jacks 16, 17, 18.

Figure 4 shows the telescopic arm elements 3, 4, 5 in the rest position, elements retracted. The internal part of the element 3 is crossed by two pipes 22 and 23 which open respectively on the lateral surface of the element 3 at the nozzles 22a and 23a. The pipe 22 also opens into a chamber 24 formed between the ends of the elements 3, 4 and 5 located to the right of the figure. This chamber is closed by the bottom 5a of the element 5.

Furthermore, the pipe 23 terminates and can be placed in communication with one or the other (or both) of the chambers 25 and 26 formed respectively between the external surface of the element 3 and the internal surface of the element 4, and between the external surface of the element 4 and the internal surface of the element 5. An orifice 27 formed in the element 4 allows the chamber 25 to be placed in communication with the chamber 26.

The pipes 22 and 23 and the chambers 24, 25 and 26 of FIG. 4 are filled with the working fluid which has been represented in the form of a special gray, when the pressure of the fluid is zero or when the fluid is in situation back to the hydraulic pump (not shown) while we have shown in another gray (for example chamber 24 of FIG. 5) when the fluid is under pressure to cause the extension of the internal volume of the jack or when (case of chambers 25 and 26 of Figure 9) the pressurized fluid causes the retraction of the telescopic arm elements one inside the other.

It can therefore be seen, from what has just been described, that in FIG. 4, in all the chambers and in the two pipes, the fluid is at rest and without internal pressure.

If we now examine Figure 5, we see that we send the pressurized fluid in the pipe 22, we cause the extension of the volume of the chamber 24 until the internal rim 28 of the element 5 comes into contact with the internal rim 29 of the element 4. If, from this position, one continues to send fluid under pressure, the element 5 drives the element 4 and a second chamber is created extension 30 (figure 6). In the situation in FIG. 5, the chamber 26 has been reduced to zero volume while the chamber 25 has kept its own volume. The fluid discharged from the chamber 26 is therefore returned to the pump through the orifice 27 and the pipe 23, through the nozzle 23a. In the case of FIGS. 5 and 6 the nozzles 22a and 23a are respectively nozzles for admission under pressure of the working fluid and for return to the pump of the pressureless fluid. Indeed, with reference to FIG. 6, it can be seen that the element 4 has moved to the right relative to the element 3, until the internal rim 31 of the element 4 has come into contact with the internal rim 32 of the element 3. During this stroke, the volume of the chamber 25 (just as before the internal volume of the chamber 26) was reduced to zero, and the fluid was discharged to the pump by the pipe 23 and the nozzle 23a.

In FIG. 6, the pressurized fluid has therefore brought the successive elements of the telescopic arm 3, 4, 5 to their position of maximum extension.

The kinematic position of the elements of the telescopic arm shown in Figure 7 is the same as that shown in Figure 6. With the difference that the gray of the internal parts, in Figure 7, is that of the rest position 'elements out.

When you want to bring the elements one into the others, we will first of all cause the retraction of all the elements 4, 5 on the element 3 until the element 4 (end B3) comes into abutment on the flange 34 of the element 3 , then the element 5 will then be retracted on the element 4 until the end piece 35 abuts on the rim 36 of the element 4.

To this end, the functions of the external pipes (not shown) which end at the nozzles 22a and 23a are reversed, so that the nozzle 23a admits the fluid under pressure first into the chamber 26 to cause its extension and bring the assembly 4.5 back to the element 3 (case of FIG. 8) then into the chamber 25 by communication through the orifice 27 in order to bring the element 5 back to the element 4 (case of the figure 9). In this cylinder retraction movement, to retract the arm elements one into the other, the chamber 30 first (FIG. 8) then the chamber 24 (FIG. 9) decrease in volume and the fluid returns to the pump through the nozzle 22a, via line 22.

In the return situation corresponding to FIG. 9, the operating cycle is closed and we find ourselves in the position of the elements represented in FIG. 4.

It goes without saying that one can, without departing from the scope of the present invention, make any modification to the embodiments which have just been described.

In particular, it will be possible to produce the geometry of the internal chambers of the jacks as well as the path of the pipes according to any other embodiment, subject to respecting the principle of extension and retraction according to the present invention and which has just been described. in the above.

Claims (3)

1 - Telescopic type personnel lifting device comprising an orientable arm articulated at its base (2) on a carrying platform, essentially characterized in that said arm consists of two series of several coaxial elements fulfilling completely different functions and well separated: on the one hand, telescopic outer tubular envelopes (3,4,5) constituting the arm proper, and extensible with respect to each other, said envelopes being the elements carrying the boom undergoing the mechanical forces of the arm and in particular the bending forces; on the other hand, internal telescopic jacks (16,17,18) coaxial with said envelopes to which said jacks are subjected, so that said jacks do not have to undergo any bending stress and only have to work in compression pure or in pure traction, said cylinders being of the double-acting type, and being capable of being controlled in extension and in retraction by the appropriate circulation (22,23) of a fluid under pressure, the extreme envelope (5) being only made integral with the turret (6) and not the extreme jack (18), the part furthest from the base (19) ect free inside said extreme envelope (5) without interposition between the envelopes and the chain and / or roller cylinders. 2 - Machine according to claim 1, characterized in that the telescopic arm comprises three tubular cylindrical elements fitted coaxially one inside the other: a first basic element articulated on the carrying platform, a second element partially surrounding the first, and a third element partially surrounding the second, said elements defining, by the geometry of their internal parts, extension and retraction chambers, the volume modification of which is limited by the set of annular stops which cooperate with each other respectively, while it is provided in the body of the first element, inlet pipes and return of the working fluid, said pipes opening appropriately respectively in one or the other of the appropriate extension and retraction chambers. 3 - Machine according to claim 2, characterized in that the inlet pipe for the working fluid in the first phase of extension of the jacks becomes the return pipe for the working fluid in the retraction phase of the jacks, and vice versa, the return pipe of the fluid in said first phase, becomes the inlet pipe of the working fluid in said retraction sentence.

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