LU101596B1 - Energy absorber device for lifeline - Google Patents

Abstract

An energy absorber device (10) for a lifeline comprises two metal plates (20, 20 ') the plates being assembled with their fixing ends (22, 22') opposite and so as to be able, from a initial position, move relatively relative to each other in the longitudinal direction each plate has an oblong hole (28, 28 ') extending in the longitudinal direction, the oblong holes (28, 28') of both plates (20, 20 ') coinciding over most of their length in the initial position. Braking means comprise a plurality of projecting deformable elements (50, 50 ') distributed lengthwise at each oblong hole (28, 28'), and for each plate (20, 20 '), on the side of the second end (24, 24 '), an orifice (32, 32') aligned with the oblong hole (28, 28 ') of the other plate, crossed by a pin (33, 33') also engaged in the oblong hole (28, 28 ') of the other plate, so that when a tensile force is applied to at least one fixing end (22, 22'), the two plates (20, 20 ') are able to be moving axially with respect to each other, the relative displacement of the plates being effected by driving the axes (33, 33 ') in the oblong holes (28, 28'), said axes (33, 33 ') progressively deforming at least part of the projecting deformable elements (50, 50 '), so as to brake and if necessary block the relative movement of the plates (20, 20') subjected to the tensile force in the event of a fall.

Description

ENERGY ABSORBING DEVICE FOR LIFE LINE Technical field The present invention generally relates to the field of personal protection equipment against falls from a height, and in particular lifelines.

The present invention relates more particularly to an energy absorber device, intended for use at the end of a lifeline.

STATE OF THE ART Lifeline systems are systems for preventing falls from a height that have been in use for some twenty years.

These are ropes, generally metallic, permanently or temporarily installed on buildings or other structures requiring the intervention of maintenance personnel at height, or in unstable environments such as on boats for example.

The lifeline systems are designed to protect these personnel against falls while allowing them great mobility.

A lifeline system generally comprises a flexible or rigid anchor line anchored to a supporting structure such as the walls or roofs of a building or ship's deck, to which a user attaches by means of an anchor. mobile (also called mobile anchoring point, or else trolley or slider) which can move on the anchor line, the user himself being equipped with a harness connected to this mobile anchor via the intermediary of a loin.

The lifeline thus retains people in suspension by their harnesses in the event of an accidental fall.

The lifelines, and more particularly their ends and attachment points are subjected to very high stresses, in particular in tension and shear, when people fall, caused by the effect of the potential energy and, where applicable, the kinetic energy acquired by the body of people during the fall.

This is the reason why energy absorbing devices have been developed and are used to absorb the energy resulting from the accidental fall of a person and thus limit the tensile forces applied to the anchor points of the vehicle. lifeline.

These energy absorbers are generally fixed between one end of the lifeline and its terminal anchorage.

One type of energy-absorbing device is designed so that the energy of the fall is absorbed by the plastic deformation (elongation) of an element made of metallic or plastic material.

An example of such an energy absorber device is described in document US 2018/264297. The device takes the form of a curved profile itself formed of one or more coils each defining one or more curves.

The curved profile and coils are configured to gradually and sequentially deform under sudden load to provide two levels of shock absorption.

Another type of energy-absorbing device comprises a plastic cylinder with a central passage through which a wire rope passes.

A metal ball is crimped at the end of the cable and the other part of the cable is secured to the lifeline.

The metal ball has a larger diameter than the internal passage of the plastic cylinder, and is held in tension against a tapered inlet section of the internal passage.

In the event of a fall, the tensile force exerted on the cable by the lifeline will force the ball through the cylinder.

This movement of the ball is accompanied by a plastic deformation of the internal passage of the cylinder, which allows the absorption of the fall energy.

OBJECT OF THE INVENTION The object of the present invention is to provide another energy absorber device for a lifeline which is at the same time of simple construction, robust, and safe to use.

This objective is achieved by an energy absorber device according to claim 1.

General description of the invention The invention relates to an energy absorber device comprising two metal plates (at least) extending in a longitudinal direction between a first end, called the fixing end, and a second end. The plates are assembled with their opposite fixing ends so that, from an initial position, they can move relatively relative to each other in the longitudinal direction when a tensile force is applied to at least l 'one of the fixing ends.

Braking means are able to slow the movement of the two plates under a tensile force.

According to the invention, each plate has an oblong hole extending in the longitudinal direction, the oblong holes of the two plates coinciding over most of their length in the initial position. In addition, the braking means comprise a plurality of projecting deformable elements distributed lengthwise at each oblong hole, and for each plate, on the side of the second end, an orifice aligned with the oblong hole of the other plate, traversed by an axis also engaged in the oblong hole of the other plate, so that when a tensile force is applied to at least one fixing end, the two plates are able to move axially with respect to one another the other. The relative displacement of the plates is effected by driving the axes in the oblong holes, the axes progressively deforming at least part of the protruding deformable elements, so as to slow down and if necessary block the relative displacement of the plates subjected to the force. traction in the event of a fall.

The energy absorber device thus comprises a braking means implementing a mechanism with projecting elements opposing a resistance to the displacement of the axes in the oblong holes. In normal use of the lifeline, the forces exerted on the energy absorber device are insufficient to deform the protruding elements. The device therefore remains in the initial position. In the event of a fall, a significant tensile force (or fall tensile force) is exerted on the device, causing it to lengthen. The relative displacement of the plates is therefore accompanied by a displacement of the axes in the oblong holes.

During this movement, the axes must overcome the resistance opposed by the protruding deformable elements.

The protruding deformable elements thus constitute a plurality of points and friction surfaces which will make it possible to slow down or even stop the relative movement of the metal plates, therefore absorbing the energy linked to the fall.

According to one embodiment, the energy absorber device also comprises a third metal plate, similar or identical to the two metal plates with the oblong holes.

The three metal plates are assembled so that one of said so-called central metal plates is disposed between the other two so-called side metal plates, the two side plates having their fixing ends on the same side, opposite to the fixing end of the plate. center, and so that the oblong holes in the three plates coincide substantially in the initial position, the holes in the two side plates being aligned and being traversed by the same axis extending also through the oblong hole in the center plate, and the orifice in the central plate having its axis engaged through the two oblong holes of the side plates.

The use of a third metal plate makes it possible to improve the distribution of stresses within the device, as well as its performance in terms in particular of energy absorption by adding a series of deformable protruding elements.

The protruding deformable elements are disposed along at least one side of the oblong hole, preferably on both sides.

Advantageously, the protruding deformable elements are arranged in symmetrical rows on either side of the oblong hole.

In addition, the projecting elements are preferably distributed over the entire length of said oblong hole.

According to the variants, the projecting deformable elements are teeth arranged in parallel directions secant to the longitudinal axis.

The projecting deformable elements can in particular take the form of teeth arranged in a spike.

The protruding deformable elements are preferably inclined, in the initial state, towards the second end of the metal plate, forming a predetermined, acute angle α at their base. The angle a is between 40 and 80 °, preferably between 60 and 75 °, in particular around 70 °.

In other words, the protruding deformable elements are pre-oriented in the direction of their deflection caused by the passage of the axes during the movement of the metal plates.

In general, it is possible to play on the positioning and dimensioning of the projecting elements in order to vary the frictional force. The protruding elements can have constant dimensions (length / width) or vary according to the axial position. For example, protruding elements with a first width may be at the start of the race, then from a certain axial position along the oblong hole, protruding elements with a different width (for example greater), or several sizes. Also, the spacing between the protruding elements can be constant or variable. Advantageously, the protruding deformable elements comprise at their base, on the side of the acute angle a, an indentation or groove intended to facilitate their deformation. These indentations facilitate the bending of the teeth and thus promote the deformation of the protruding elements, reducing jolts and breaks.

Preferably, each plate of the energy-absorbing device comprises on its fixing side an attachment means, in particular an attachment hole passing through the plate in a region which is not, in the initial position, covered by the plate. neighboring metal. The attachment means make it possible to connect the energy-absorbing device to a lifeline.

Each axis of the present energy absorbing device is advantageously blocked transversely with respect to the oblong holes. The pins can be formed from a cylindrical rod, hollow or solid, held in place by screwing or riveting. In practice, the axes define a mounting space for stacking the slotted hole plates and possibly other elements of the device. Thus the axes also have the function of a spacer, avoiding compressing the elements or hampering their movement.

Advantageously, the energy absorber device comprises two protection plates positioned in such a way that a protection plate is mounted on the exterior face of each side plate so as to cover the oblong hole in the initial position. Each protection plate preferably has a first end mounted to pivot on one of the axes, and a second end, opposite, comprising a temporary fixing element on the other axis, configured so as to allow its release when the two axes getting closer. The temporary fixing element may in particular take the form of a hook which is engaged on the other axis in the initial position, the protective plate having an oblique edge arriving at the base of the hook, on which the other slides. axis when the axes approach. The protective plates help prevent an object from entering the slotted holes, which could jam or damage the toothed brake mechanism.

According to other embodiments, the energy absorber device comprises a housing in which the metal plates are placed so that the attachment end of the side plates protrudes outwardly through a slot in the bottom of the housing. A compression spring surrounds the metal plates and has one end in abutment against the housing and another end in abutment against protruding elements provided on the longitudinal edges of the central plate. The box includes fixing means for its integration into the lifeline, in particular to an end / terminal anchor. Such a box makes it possible to protect the energy-absorbing device in the same way as the protection plates, by making it possible to prevent an object from engaging in the oblong holes, risking blocking or damaging the braking mechanism. teeth. Advantageously, the spring makes it possible to maintain the assembly of the plates in the case while ensuring that the tension in the lifeline is maintained.

The simplicity of the present device makes it particularly robust and reliable. The different plates can be produced by cutting / machining from metal sheets. Stainless steel is particularly preferred for its resistance to corrosion, the device being exposed to the elements. Generally,

all metallic materials having appropriate mechanical properties can be used, if necessary with anti-corrosion treatment (galvanized steel, paint, etc.). The device is also particularly appreciable by the small variety of parts.

The plates with the oblong holes can be identical or very similar (it is however possible to vary the thicknesses for reasons of mechanical resistance). Thus the three plates with oblong holes are advantageously identical, based on the same model.

The two protective plates also have the same shape.

In the variants with three metal plates with oblong holes, the side plates may have the same thickness and the central plate has a thickness greater than the side plates, preferably at least double.

The greater thickness of the central plate makes it possible to improve the solidity of the device, and to increase the resistance of the deformable elements projecting from said central plate to a tensile force exerted when a user falls.

In general, the energy absorption capacity of the present device can be adjusted by adjusting the dimensioning of certain elements such as: number of deformable protruding elements, dimensions of these, axial length of the oblong hole, number of plates, constituent material thereof.

The design principle of this absorption device is compatible with the standards for lifelines because it reduces the impact forces of a fall to less than 6 kN.

The present energy absorber device is suitable for attachment to any type of lifeline, vertical, horizontal or inclined, or comprising vertical, horizontal or inclined portions.

In particular, the present energy absorber device can be used on already existing lifelines, which facilitates its installation and reduces the costs linked to the deployment of such a device.

Detailed description with the aid of the figures Other features and characteristics of the invention will emerge from the detailed description of some advantageous embodiments presented below, by way of illustration, with reference to the accompanying drawings.

These show: Fig. 1: a front view of an embodiment of the energy absorber device according to the invention; Fig. 2: a front view of the energy absorbing device of FIG. 1 after absorption of the energy due to a fall; Fig. 3: a front view of a metal plate of the energy absorber device of FIG. 1; Fig. 4: a front view of the energy absorber device of FIG. 1 in its initial configuration; Fig. 5: a sectional view A-A of the energy absorbing device of FIG. 4; Fig. 6: a view of detail B of FIG. 5; and Fig. 7: a perspective view of a second embodiment of the present energy absorber device.

In the figures, the same reference signs designate identical or similar elements.

An energy absorber device 10 according to the invention is presented here, in which the device comprises three metal plates.

The plates are arranged substantially parallel to each other (Fig.5). A plate 20, called the central or main plate, is therefore located between two other plates 20 ', which are called side plates or secondary plates.

In Figs. 1 and 2 only one of the two side plates 20 'can be distinguished (the second side plate being located behind and perfectly superimposed). The three metal plates 20, 20 'each extend in a longitudinal direction (axis L) between a first end 22, 22' called the fixing end, and a second end 24, 24 '. Each of the plates 20, 20 'has on its fixing end 22, 22' a fixing hole 26, 26 'passing through the plate.

The fixing holes 26, 26 'allow the energy absorber device to be attached to a lifeline (not shown). Device 10 is typically mounted at one end of a lifeline.

In the initial position, the plates are assembled so that the fastening ends 22 'of the side plates 20' are opposite the fastening end 22 of the central plate 20.

It will be noted that in the variant the three metal plates 20, 20 'are designed on the same model. Fig.3 shows a front view of the central plate 20, but the side plates 20 ’are identical, except for their thickness, and therefore have the same structure.

Each metal plate 20, 20 'also has an oblong hole 28, 28' extending in the longitudinal direction L. In the initial position of the device 10 (Fig. 1, 4 or 5) the plates are positioned so that the oblong holes 28, 28 'coincide along their length. That is to say, the oblong holes 28, 28 'constitute axial slots which are aligned along most of their length.

A plurality of protruding deformable elements 50, 50 'are distributed lengthwise at each oblong hole 28, 28 ". In the present variant, the projecting deformable elements 50, 50 'are teeth arranged in symmetrical rows on either side of the oblong holes 28, 28' over the entire length thereof. As seen in Fig. 3, the teeth 50 are arranged in parallel directions secant to the longitudinal axis of the oblong hole 28 so that these secant parallel directions form with the longitudinal axis L of the oblong hole 28, on the side of the second end 24 of the metal plate 20, an angle a. It will be noted that the teeth are, in their initial configuration, inclined towards the second end 24 of the plate. The angle a is an acute angle which can have a value between 40 and 80 °, preferably between 60 and 75 °, in particular about 70 °. The teeth 50 'are arranged in a similar manner on either side of the oblong holes 28' of the side metal plates 20 ". Each metal plate 20, 20 'also has an orifice 32, 32' on the side of the second end 24. , 24 '. As best seen in Fig. 6, the orifice 32 is crossed by a shaft 33 in the form of a cylindrical sleeve, here held by rivets 34, which is also engaged in the oblong holes 28' of the plates. side 20 ', between the edge of said oblong holes on the side of the first end 22' and the first pair of teeth 50 '. Similarly, the holes 32', aligned, are crossed by a pin 33 ', held by rivets 34 ', also engaged in the oblong hole 28 of the central plate 20 between the edge of said oblong hole 28 on the side of the first end 22 and the first pair of teeth 50. The positions of the two axes 33 and 33' are indicated. dotted lines in Fig. 3. The present device 10 is based on a principle of absorption of energy. Energy from plastic deformation of teeth 50, 50 "through pins 33, 33" as the center plate and pair of side plates are moved in opposite directions under the effect of a tensile force generated by a fall.

Fig.2 shows the energy absorbing device of Fig.1 after absorption of the energy due to the fall of a user.

Starting from the initial position of Fig. 1, when the energy absorbing device 10 is subjected to a fall tensile force applied to one of the fixing ends 22, 22 ', the three metal plates 20, 20' undergo a relative axial displacement: the central plate moves away from the air gap of the side plates.

This movement causes the movement of the rivets 34, 34 'within the oblong holes 28, 28'. The teeth 50, 50 'oppose the displacement of the rivets 34, 34' and are deformed as they pass, as seen in Fig.2. The deformation of the teeth 50, 50 'makes it possible to absorb the potential and kinetic energies of the fall of a user, and to slow down or even block the relative movement of the metal plates 20, 20 ". The general operating principle having been presented, certain implementation details will be described below.

The metal plates are preferably cut / machined, with the holes, orifices and teeth, in steel plates, even if any mode of manufacture is conceivable.

For reasons of mechanical strength, the central plate has a thickness which is twice that of the side plates.

The teeth 50, 50 'preferably present at their base, on the side of the acute angle, therefore on the side of which they will deform, an indentation 52, 52 ". This indentation facilitates plastic deformation on this side of the tooth, preventing the formation of a bulge at its base. As will be understood, the teeth are, in the initial position, inclined in the direction in which they will be deformed by the axes 33, 33 ".

The energy absorber device 10 advantageously comprises two protective plates 40, 40 '. The plates 40, 40 'are mounted on the outer faces of the side plates 20'. In the initial position, the protective plates 40, 40 'cover the oblong holes 28, 28' so as to prevent an object from engaging therein, risking blocking or damaging the toothed braking mechanism.

The protective plates 40, 40 'are pivotally mounted on the axis 33 and extend to the opposite axis 33 ′, from which they disengage in the event of a fall.

The protection plate 40 has a first end 42 pivotally mounted, through an orifice 31, on the axle 33. The second end 44 of the protection plate 40 comprises a fastening element, here taking the form of a hook 35, which is engaged on the axis 33 'in the initial position. It will be noted that the front edge 37 of the second end of the protection plates is oblique with respect to the longitudinal direction, and arrives at the base of the hook 35. This edge 37 therefore forms a sliding edge which will facilitate the release of the plate. protection 40 when the two axes 33 and 33 'will approach under the tensile force of the fall. The second protection plate 40 'is of identical construction to the protection plate 40.

Referring to Fig. 6, it will be observed that the length of the axis 33, 33 ’is greater than the cumulative thickness of the five metal plates, so as not to clamp the plates together. The rivets 34, 34 '(of the hollow type) are engaged on both sides of the pins 33, 33 ". Washers 36, 36' are interposed between the heads of the rivets 34, 34 'and the ends of the pins 33, 33'. These washers allow better transverse locking of the pins, and better guidance along the oblong holes, preventing the pins 33, 33 'from getting askew.

Spacers 60 in the form of washers are placed between each of the plates 20, 20 °, 40 and 40 ', and under the washers 36, 36 ". The washers 60 may be metallic or of a polymer material (eg PTFE). It will be noted that that in the initial position, the hooks 35 of the protective plates are engaged under the washers 36 ', between two spacers 60.

The metal plates 20, 20 ', or in general the metal parts, are preferably made of stainless steel, for example AISI 304 stainless steel. However, this example is not limiting. Any other steel with suitable mechanical and anti-corrosion properties can however be used.

The rivets are made of an anti-corrosion material, for example aluminum.

The energy absorption capacity of the present device can be adjusted by adjusting the dimensioning of certain elements such as: number of deformable projecting elements, dimensions of these, axial length of the oblong hole, number of plates, constituent material of these. The design principle of this absorption device is compatible with the standards relating to lifelines because it reduces the impact forces of a fall to less than 6 kN.

By way of example, and in a nonlimiting manner, in the context of conventional lifelines and in consideration of standards, some examples of dimensions can be cited: - the oblong hole can have an axial length L1 between 100 and 400 mm and a width L2 between 20 and 30 mm, depending on the application, in particular depending on whether the device is installed vertically or horizontally. For vertical lifelines, the oblong hole can have an axial length between 100 and 200 mm.

- The teeth may have a length L3 between 10 and 15 mm, and a width L4 between 2 and 5 mm, in particular between 3 and 5 mm.

- the spacing E between the teeth can vary between 8 and 16 mm, in particular 9 to 14 mm.

1 |

Figure 7 shows a variant of the present energy absorber device which comprises three metal plates 120, 120 ’of the type of Figure 3 mounted according to the principle of the previous variant. We therefore have an assembly of the three plates 120, 120 ’identical to that of the variant of Figs. 1 to 5, but without protective plates. Here the three plates 120, 120 'are placed inside a case 160, here cylindrical, closed on one side by a bottom 162 and on the other by a plug 164. The pins 133, 133' are fixed. in the same way as in the previous variant and therefore engaged in all oblongs of the plates 120, 120 °.

On the side of the plug 164, the box comprises a fixing end 166 with two protruding portions 168 each carrying a hole through which a bolt or threaded rod 170 passes, which allows fixing to a terminal anchor.

A slot 171 is made in the bottom 162 of the housing 160 to let the fixing end 122 ’out of the two side plates 120’. It will be noted that the central plate 120 does not include any attachment means since the assembly is secured by the attachment end 166 of the housing 160.

A coil spring 172 is placed in the housing and around assembly plates 120, 120 ". It comes into abutment on the bottom of the case and rests, on the other hand, on two projecting lugs 174 provided on the longitudinal edges of the central plate 120. The spring 172 therefore makes it possible to maintain the assembly of the plates in the case. while ensuring that tension is maintained in the lifeline.

Claims (20)

Claims 1. Energy absorber device (10) intended to be installed at the end of a lifeline comprising: - two metal plates (20, 20 ") extending in a longitudinal direction (L) between a first end (22, 22 "), called the fixing end, and a second end (24, 24"), the plates being assembled with their fixing ends (22, 22 ") opposite and so as to be able, from an initial position, to move relative to each other in the longitudinal direction when a tensile force is applied to at least one of the fixing ends (22, 22 "); - means brake suitable for braking the movement of the two plates under a tensile force; characterized in that each plate has an oblong hole (28, 28 ") extending in the longitudinal direction, the oblong holes (28, 28") of the two plates (20, 20 ") coinciding over most of their length in the initial position, and in that the braking means com take: - a plurality of projecting deformable elements (50, 50 ") distributed lengthwise at the level of each oblong hole (28, 28"), and - for each plate (20, 20 "), on the side of the second end (24, 24 "), a hole (32, 32") aligned with the oblong hole (28, 28 ") of the other plate, crossed by a pin (33, 33") also engaged in the oblong hole ( 28, 28 ") of the other plate, so that when a tensile force is applied to at least one fixing end (22, 22"), the two plates (20, 20 ') are able to move axially with respect to one another, the relative displacement of the plates being effected by driving the pins (33, 33 ") in the oblong holes (28, 28"), said pins (33, 33 " ) progressively deforming at least part of the protruding deformable elements (50, 50 "), so as to slow down and if necessary block the relative movement of the plates (20, 20") subjected to the tensile force in fall case. 2. Energy absorber device (10) according to claim 1, characterized in that it comprises a third metal plate similar or identical to said two metal plates (20, 20 "), the three metal plates (20, 20") being assembled so that one of said so-called central metal plates (20) is disposed between the other two so-called lateral metal plates (20 '), the two side plates having their fixing ends (22') on the same side, opposite to the 'fixing end (22) of the central plate (20), and so that the oblong holes (28, 28 ") in the three plates coincide substantially in the initial position, the holes (32") in the two side plates being aligned and traversed by the same axis (33 ') also extending through the oblong hole (28) of the central plate (20), and the orifice (32) in the central plate having its axis (33) engaged through the two oblong holes (28 ') of the side plates. 3. An energy absorber device (10) according to any preceding claim, wherein said protruding deformable members are disposed along at least one side of the oblong hole, preferably on both sides. 4. Energy absorber device (10) according to claim 3, wherein the projecting deformable elements (50, 50 ") are arranged in symmetrical rows on either side of the oblong hole (28, 28"). 5. An energy absorber device (10) according to any preceding claim, in which the protruding deformable elements (50, 50 ") are distributed over the entire length of the oblong hole (28, 28). 6. An energy absorbing device (10) according to any one of the preceding claims, in which the spacing (E) between the protruding deformable elements (50, 50 ") is constant or variable; and / or them. dimensions of the projecting deformable elements (50, 50 "), in particular length (L3) and width, are constant or variable. 7. Energy absorber device (10) according to any one of the preceding claims, in which the protruding deformable elements (50, 50 ") are teeth arranged in parallel directions secant to the longitudinal axis (L). . 8. Energy absorber device (10) according to claim 7, characterized in that the projecting deformable elements (50, 50 ") are teeth arranged in a spike. 9. Energy absorber device (10) according to claim 7 or 8, wherein the projecting deformable elements (50, 50 ") are inclined, in the initial state, in the direction of the second end (24, 24). ") of the metal plate (20, 20"), forming a predetermined acute angle α at their base. 10. An energy absorbing device (10) according to any one of claims 6 to 8, in which the angle a is between 40 and 80 °, preferably between 60 and 75 °, in particular about 70 °. . 11. An energy-absorbing device (10) according to claim 8, wherein the projecting deformable elements (50, 50 ") have at their base, on the side of the angle a, an indentation (52, 52"). 12. An energy absorbing device (10) according to any one of claims 2 to 10, wherein the side plates (20 ") have the same thickness and the central plate (20) has a thickness greater than the side plates. (20 "), preferably at least double. 13. An energy absorbing device (10) according to any one of the preceding claims, in which each plate (20, 20 ") comprises, on its fixing side (22, 22"), an attachment means. (26, 26 "), in particular a fixing hole passing through the plate (20, 20") in a region which is not, in the initial position, covered by the neighboring metal plate. 14. An energy-absorbing device (10) according to any one of the preceding claims, in which each axis (33, 33 ") is blocked transversely. 15. An energy-absorbing device (10) according to claim 14, wherein each axis (33, 33 ") is formed of a cylindrical rod, hollow or solid, held by screwing or riveting. 16. An energy absorbing device (10) according to any one of claims 2 to 15, in which a protective plate (40, 40 ") is mounted on the outer face of each side plate (20 ') of. so as to cover the oblong hole (28, 28 ") in the initial position. 17. An energy absorbing device (10) according to claim 16, wherein the protective plate (40, 40 ") has a first end (42) pivotally mounted on one of the axes (33, 33"). ; and a second end (44), opposite, comprising a temporary fixing element (35) on the other axis (33, 33 "), configured so as to allow its release when the two axes approach. 18. An energy absorbing device (10) according to claim 17, wherein the temporary fixing member (35) is in the form of a hook which is engaged on the other axis (33, 33 ") in the position. initial, the protection plate (40, 40 ') having an oblique edge (37) arriving at the base of the hook, on which the other axis slides when the axes (33, 33 ") approach. 19. An energy absorbing device (110) according to any one of claims 2 to 15, comprising a housing 160 in which: the metal plates (120, 120 ") are placed so that the fixing end of the side plates (120 ') protrude outward through a slot in the bottom (162) of the housing; a compression spring (172) surrounds the metal plates (120, 120 ") and has one end abutting against the housing (160) and another end in abutment against projecting elements (174) provided on the longitudinal edges of the central plate (120); and the box (160) comprises fixing means (170) for its integration into the lifeline, in particular to an end anchor. 20. A lifeline comprising an energy absorber device (10, 110) according to any one of the preceding claims.