EP1466650B1 - Lifeline with fall absorber - Google Patents

Description

The present invention relates to a life line fall shock.

In general, it is known that, in order to ensure the safety of people working on a roof, safety standards recommend the use of lifelines comprising a steel cable stretched between two fixed anchoring elements. on the frame. Thus, this cable is frequently permanently installed in parallel and at a predetermined distance from the ridge.

The tension of this cable is ensured by means of a cable tensioner of conventional type interposed between one of its ends and its anchoring element.

With these provisions, each person on the cover and equipped with a harness (or harness) can hook to this cable through a link (for example a lanyard or a strap) connected on one side to harness (or shoulder harness) and, on the other side, a carabiner that can be mounted on the cable and slide along it.

The length of this link is determined by standards according to the dimensions of the roof.

Usually, to allow the person to work unhindered, the link between the link and the harness or harness is in the dorsal region of it.

It turns out that, during a fall, the person who falls is too brutally restrained by the link: this brutal reaction of the link when it comes into tension can cause significant trauma. This type of trauma can be particularly serious in the case of a dorsal attachment since, in this case, the reaction of the link is exerted directly on the spine of the person.

The use of resilient means for damping this impact, for example an elastic link, is not a satisfactory solution because of the restoring force exerted by these elastic means after solicitation.

It is the same with regard to the shock absorbing devices such as that described in US Patent 5,458,214: Here also when the tensile force exerted on the damping device ceases, the elastic elements used resume their shape. initial and therefore exercise a restoring force.

The object of the invention is therefore more particularly to eliminate these disadvantages.

For this purpose, it proposes a lifeline with a drop damper comprising a cable stretched between two anchoring elements fixed on the roof and a link one end of which is slidably mounted on the cable, while the other is connected. fastening means such as a harness or a harness, this lifeline comprising in series with said cable or said link a damping device comprising elastic means subjected to tensile forces of said cable and / or said link.

According to the invention, this device is characterized in that the said elastic means consist of a helical spring which can deform linearly as a function of the traction exerted by the aforesaid cable or the aforesaid connection, and in that it comprises means of retention consisting of a rack system secured to one of the ends of the spring, this rack system comprising notches cooperating with a snap fastened to the other end of the spring so as to make the deformation of the spring and means for return the spring to its initial position after it has undergone a remanent deformation.

In this case, the return of the spring to its original position can be obtained by exerting an action on the snap to release the rack.

According to an alternative embodiment, the aforesaid rack system may comprise a wolf-tooth helical threaded rod cooperating with pawls so that, during a deformation of the spring generated by pulling the cable, it occurs. a relative displacement between the rod and the ratchets (which slide on the slightly inclined edges of the net) and that, when this traction stops, the spring is held in its position thanks to the engagement of the pawls on the net (the pawls coming into stop on the abrupt forehead of the net).

This solution has the advantage of allowing to bring the spring back to its original position by a simple relative rotation between the rod and the pawls: this operation can be performed without causing sudden return of the spring and therefore without danger. In addition, it ensures the initial tension of the cable, which avoids having to use a cable tensioner.

• La figure 1 est une représentation schématique d'une ligne de vie montée sur une couverture à proximité d'un faîtage ;
• Les figures 2 à 4 sont des vues en perspective des différents éléments de la ligne de vie représentée sur la figure 1, à savoir : un élément d'ancrage d'extrémité (figure 2), un élément de guidage intermédiaire (figure 3) et un tendeur de câble (figure 4).
• La figure 5 est une coupe axiale d'un élément amortisseur utilisant un dispositif de rétention à tige crantée.
• La figure 6 montre une variante d'exécution d'un élément amortisseur utilisant une tige à filet hélicoïdal.

Embodiments of the invention will be described below, by way of non-limiting examples, with reference to the accompanying drawings in which:

• Figure 1 is a schematic representation of a lifeline mounted on a cover near a ridge;
• FIGS. 2 to 4 are perspective views of the various elements of the lifeline shown in FIG. 1, namely: an end anchoring element (FIG. 2), an intermediate guiding element (FIG. 3) and a cable tensioner (Figure 4).
• Figure 5 is an axial section of a damping element using a toothed rod retention device.
• Figure 6 shows an alternative embodiment of a damping element using a helical threaded rod.

In the example shown in Figure 1, the lifeline 1 consists of a steel cable 2 stretched between two anchoring elements 3, 4 by means of a conventional cable tensioner 5 (located between the its ends 6 and the element 3).

This lifeline 1 further comprises a damper 7 mounted between the other end 8 of the cable 2 and the other anchoring element 4, as well as holding and guiding elements 9 of the cable arranged at regular intervals (for example every 5 m).

In this example, the anchoring elements 3, 4 are fixed to the top of a roof 10, so that the cable 2 extends parallel to and near the ridge 11. Of course, the position of these elements d anchorage 3, 4 in relation to the shores and gables of the roof must comply with the safety regulations in force.

The cable 2 is intended to receive carabiners 12 connected to insurance links (lanyards, straps or insurance ropes), themselves attached to harnesses 13 or harnesses worn by people working on the roof. These carabiners 12 can slide along the cable 2 so as to allow these people to move parallel to the ridge 12 while remaining assured.

The anchoring elements 3, 4 may consist, as illustrated in FIG. 2, in an angle section of which a flange 14 of rectangular shape is provided with a plurality of bores for fastening the element to a blanket by screwing, and the other wing 15, of substantially triangular shape, is provided, at its top, with a bore 16 intended to allow the attachment of one end of the cable 2 directly or via an accessory such as, for example, the cable tensioner 5 or the damper 7. This triangular wing further comprises two holes 17, 18 to ensure the attachment of an additional anchoring piece 19 provided with an orifice 20 serving as a fixed anchor point.

The holding and guiding elements 9 also consist of angles sections having a rectangular fixing wing 21 provided with bores and a trapezoidal wing 22 whose large base is integral with the wing 21, while the small base is extended by two curved tabs of opposite concavities 23, 24. These two tabs 23, 24 which are axially offset define a passage through which the cable 2 and the carabiners 12 sliding on the cable 2 can pass.

The cable tensioner 5 used in this example conventionally comprises two coaxial nuts 25, 26 connected to each other by an H-shaped connecting piece. In each of these nuts 25, 26 engage and engage with each other. screw two respective screws 27, 28, the heads of which are constituted by hinge clevises each having a transverse axis intended to engage in the orifice of an anchoring element 3, 4 or a loop formed to the end of the cable 2.

As shown in Figure 5, the damper 7 consists of a cylindrical tubular body 30 closed on one side by a bottom 31 provided with a central bore 32 in which is engaged and fix a clevis articulation 33. In this example, this yoke 33 has a U-shaped structure comprising two parallel wings connected by one of its ends by an axially extended core by a threaded rod which engages in the orifice 32. The fixing is then obtained by screwing a nut 34 with the interposition of a washer.

The second end of the tubular body is equipped with a bearing 35 in which a rod 36, terminated on one side by a yoke 37 and on the other side by a thread on which a nut 38 is screwed, engages and can slide.

In its centering portion, the rod comprises a series of annular wolf teeth 39, each comprising, on the bottom side, a stiff front 40 (perpendicular to the axis of the rod 36) and, on the other side, a conical front 41 with a relatively gentle slope.

These notches 39 are intended to cooperate with a snap comprising at least one jaw 42 comprising two jaws 43, 44 located on either side of the rod 36 in two diametrically opposite locations. These two jaws 43, 44 each have a rectangular trapezoidal shape whose large 45 oblique base is located on the rod side and is oriented parallel to the conical face 39 of the notches of the rod while the larger of the two parallel sides 45 '( which extends radially) is intended to serve as a backstop for the steep edge 40 of a notch.

The two jaws 43, 44 are pivotally mounted around two substantially parallel axes which extend in a plane perpendicular to the axis of the rod: these two axes here consist of two opposite portions of an annular ring 46 passing through two orifices corresponding to the middle portion of the jaws 43, 44. The two jaws 43, 44 are biased by an elastic ring 47 so that their angular region delimited by the large base 45 and the long side 45 'bear on the stem 36.

As a whole, the jaw 42 is axially retained in a space delimited by the bearing 35 and an annular element 48 integral with the inner wall of the body 30.

Furthermore, the rod 36 is subjected to the action of a helical spring 49 disposed coaxially inside the body 30 around the rod 36 and one end bears on the annular element 48, while the other end is retained by the nut 34 by means of a washer 50 of outside diameter substantially equal to the inside diameter of the body 30.

Advantageously, the end of the rod 36 adjacent to the yoke 37 may comprise a graduation for adjusting the tension of the cable 2 to the image of a conventional dynamometer.

Thanks to these provisions, during the installation of the lifeline 1, the operator acts on the cable tensioner 5 until the tension of the cable reaches the desired value (indicated on the graduation). During this adjustment phase, the rod 36 moves axially by compressing the spring 49. The jaws 43, 44 remain in abutment on a smooth portion of the rod 36 adjacent to the yoke 37. This cable tension 2 must be sufficient so that persons who are hooked there can perform light traction without this resulting in a significant deformation of the cable 2 and / or a snap of the jaw on a notch of the rod 36.

When the traction exceeds a predetermined value, for example following a fall of a person, the rod 36 subjected to a large tensile force, moves axially. During this movement, the jaws 43, 44 are successively spaced to allow the passage of the notches 39 until the balance of forces is reached. In this case, the jaws 43, 44 are closed on the rod 36, the long side 45 'abutting on the stiff front 40 of the last notch passed through the jaw 42.

The damper 7 then remains locked in this position. As a result, the fall victim does not suffer the sudden force exerted by the spring to return to his original position. Preferably, this return to the initial position will be provided at the factory using means to prevent the release of the spring does not occur suddenly putting the operators in danger. This release can be obtained by exerting on the jaws 43, 44 a force tending to tilt them, thus making them escape the notches 39. For this purpose, orifices 52, 53 may be provided in the cylindrical body 30 to allow exert this effort by means of a special tool.

Of course, the invention is not limited to the embodiment of the damper described above.

Thus, the toothed rod may be replaced by a rod 54 with helical thread 55 with wolf teeth (having an abrupt flank and a slightly inclined flank). In this case, the jaws 43 ', 44' will be specially shaped to cooperate with the thread 55. The operation of this damper is very similar to the previous one. However, in this case, the return of the rod 54 to its original position after performing its damping function can be simply ensured by pivoting the rod 54 relative to the body 30, so as to generate a process of unscrewing . This gives a return to the original position without risk for the operator.

This solution also avoids the use of a cable tensioner. Indeed, this function can be simply obtained by rotating the body of the damper, so as to cause a screwing process of the rod 54 on the jaws 43 ', 44'. In this case, the yoke 33 'must be rotatably mounted in the bottom 31 of the body 30.

Optionally, this yoke may be integral with a threaded rod 56 which is screwed into the bottom 31. By providing for this rod 56 a reverse pitch from that of the rod 54, the cable voltage adjustment means the effects are added to those obtained with the jaw pair 43 ', 44' / rod 54.

Claims (7)

1. Lifeline with fall arrest comprising a cable (2) stretched between two anchorage elements (3,4) fixed onto the roofing, and a lanyard of which one end is slidingly mounted on the cable (2) while the other end is joined to fixing means such as a harness (13), this lifeline, in series with said cable or said lanyard, comprising a fall arrest device (7) comprising elastic means (49) subjected to the traction forces of said cable (2) and/or of said lanyard, characterized in that said above elastic means consist of a spiral spring (49) able to deform linear fashion in relation to the traction force exerted by said above cable (2) or said above lanyard, and in that it comprises retaining means consisting of a rack system (36,39) joined to one end of the spring (49), this rack system comprising notches (39) cooperating with a detent (42,43,44) joined to the other end of the spring (49) so as to achieve remanent deformation of the spring, and means able to bring the spring (49) back to its initial position after it has undergone remanent deformation.
2. Lifeline as in claim 1, characterized in that said above fall arrest (7) is arranged between one of the ends of the cable (2) and its anchorage element (4).
3. Lifeline as in claim 1, characterized in that it comprises means (52,53) able to exert action on the detent (42) to release the rack (36,39) and enable its return to its original position.
4. Lifeline as in any of the preceding claims, characterized in that said above rack system (36, 39) comprises a rod (36) provided with a series of annular scalloped notches (39) and a detent device comprising two jaws (43,44) positioned either side of the rod (36), these two jaws (43,44) being toggle-mounted and on which demand is placed by elastic means (47) in the direction of the rod (36).
5. Lifeline as in any of claims 1 to 3, characterized in that said above rack system comprises a rod (54) with a spiral scalloped thread (55) cooperating with pawls (43', 44') so that when deformation of the spring (49) occurs generated by traction of the cable (2), there is relative displacement between the rod (54) and the pawls (43',44') which slide on the slightly inclined fronts of the thread (55), and when this traction is no longer exerted the spring (49) is maintained in its position through engagement of the pawls (43',44') on the thread (55), the pawls (43', 44') coming to abut the steep front of the thread (55).
6. Lifeline as in any of the preceding claims, characterized in that the rack system comprises a graduation allowing adjustment of the tension of the cable (2).
7. Lifeline as in any of the preceding claims, characterized in that the fixing of said above fall arrest (7) to its anchorage element (4) is made by means of a clevis (33') provided with a rod (56) which screws into a threaded bore in the bottom part (31) of the body (30) of said fall arrest (7).

Images