FR2740507A1 - SAFETY DEVICE FOR LADDER AND SCALE EQUIPPED WITH SUCH A DEVICE - Google Patents

Abstract

The invention relates to a safety device for a ladder. It comprises in combination two pivoting arms (8) mounted on the upper part (3) of the ladder (2), able to take an open position in which they leave between them sufficient space for the passage of a post (1 ) and a closed position in which these arms are clamped against said post (1), a rope (13) connecting said arms to the lower part of the ladder (2) to exert on the arms (8) a force which tends to cause them to close when this rope is pulled down, said rope serving as a lifeline by comprising a self-locking sliding handle to which can be connected a harness worn by the user of the ladder. The invention also relates to a ladder comprising such a safety device.

Description

The present invention relates to a safety device for

  ladder and a ladder equipped with such a device.

  To maintain overhead cables, including power lines or telephone, it is sometimes necessary to perform interventions at the top of the posts that support these cables. When the post is a simple smooth mat, we use a ladder, usually telescopic, that is pressed against the top of the pole. Nevertheless, this operation is not without presenting certain dangers, and this, especially as some poles can rise quite high. Ladder safety devices are already known which allow a ladder to be locked to a pole by means of operations

  tuning, usually long and complicated.

  However, these devices are not entirely satisfactory because their manipulation is not easy, which encourages users

  of scales not to implement them.

  Moreover, we know the lifelines that are ropes

  which can be tied to prevent a fall.

  The present invention aims at providing a blocking device

  a ladder against a mast that solves the problems mentioned above.

  This device finds its application in many other fields than the maintenance of overhead cables, such as for example the maintenance of trees and more generally any activity in which a ladder must be supported against a substantially vertical cylindrical support. The present invention relates to a ladder safety device, characterized in that it comprises in combination two pivoting arms mounted at the upper part of the ladder, able to assume an open position, or a rest position, in which they leave between them a sufficient space for the passage of a post and a closed position, or working position, in which these arms are tight against said post, a rope connecting said arms to the lower part of the ladder to exert on the arms a force that tends to cause their closure when the rope is pulled down, said rope serving as a lifeline comprising a self-locking sliding handle to which can be

  connected a harness or belt worn by the user of the ladder.

  It is understood that, thanks to the invention, the user can apply the upper end of the ladder against the pole, while the arms -2 - are in the open position, after which it suffices to exercise a pull on the rope to close the arms around the pole and fix the

  bottom of the rope to scale to ensure a first maintenance of the ladder.

  The user then hooks his harness or belt to the self-locking handle of the lifeline and climbs onto the ladder, while the self-locking handle slides along the rope that serves as the

lifeline.

  If, as a result of a false movement, the user of the ladder falls or is out of balance, he pulls the lifeline through his harness and causes an increase clamping forces of the arms against the post, which has the effect of ensuring a perfect connection between the upper part of the

the ladder and the pole.

  In a preferred embodiment, the arms in the open position are brought completely on the face of the ladder which is not applied against the post so as to limit the bulk of the upper part.

  of the ladder when positioning against the pole or against a tree.

  This embodiment is particularly advantageous because it reduces the size of the scale, which can be interesting

  to store it or to intervene on a mast located in branches.

  This embodiment also makes it possible to use the ladder against a wall, in the manner of a traditional ladder, without having to

remove the locking device.

  In a preferred embodiment, the arms move from their open position to their closed position when pulling the rope towards the lower part of the ladder, while springs, preferably helical, act on the arms to bring them back. constantly in the open position. In this way, the pivoting arms are not likely to move to come against the face of the ladder which is directed against the

  post when positioning the ladder.

  In a particular embodiment of the invention, the arms are articulated in the vicinity of one of the uprights of the ladder, around an axis

  substantially vertical when the ladder is in use position.

  Thus, the movement of the arms passing from one position to another takes place in a substantially horizontal plane when the ladder is

in position of use.

  Preferably, the rope is connected to each arm at a point of this

  arm located substantially 10 cm from its pivot axis.

  In a particular embodiment of the invention, a slightly curved bearing surface is situated substantially at the height of the two arms and makes it possible to support the ladder against the post by centering the latter.

  in the central part of the support range.

  In a preferred variant of this embodiment, the bearing surface comprises rollers capable of rolling along the post to facilitate the installation and possibly the deployment of the ladder, the

  bearing range being already applied against the pole.

  The present invention also relates to a ladder provided with

  a security device as described above.

  In order to better understand the invention, will now be described an embodiment given by way of non-limiting example with reference to the accompanying drawing in which: - Figure 1 is an elevational view of a user mounted on a scale according to the invention applied against a pole, - Figure 2 is a perspective view of the upper part of the scale, - Figures 3, 4, 5 and 6 are top views of the scale at during the placement of the arms around the post, - Figure 7 is a side view of a self-locking handle engaged on the rope, and - Figure 8 is a front view of the lower part of the ladder. FIG. 1 shows a vertical post 1, against which a scale 2 according to the invention is supported by its part

  superior 3. A user 4 is climbing to the top of the ladder.

  In Figure 2, we see how the scale 2 is gripped

post 1.

  At its upper part 3, the ladder comprises a safety device 5 which comprises two rectangular section tubes 6 each engaged at the top of one of the uprights 2a, 2b of the ladder and clamped by

collars 6a, 6b.

  Sleeves 7 are welded to the outer lateral face of the tubes 6 in a direction such that the sleeves 7 are substantially vertical when the ladder is pressed against the post 1, as can be seen

in Figure 1.

  Each sheath 7 receives the vertical branch of an arm 8, suitable for

pivot in said sheath.

  A pin 9 holds each arm axially in the corresponding sheath. Each arm 8 is thus able to pivot in a plane substantially

  horizontal, as will be explained with reference to Figures 3 to 6.

  Torsion springs, not shown, are fixed on the one hand to the lower end of each arm, on the other hand to the corresponding tube 6 and provide the return of the arms in the closed position shown in FIG.

figure 3.

  The horizontal branch of each arm 8 terminates in a curved portion whose curvature is directed towards the ladder so as to effectively clamp the post 1 by immobilizing it from an area situated substantially at

  equal distance of the two sleeves 7.

  The safety device 5 also comprises a bearing surface 10 which is constituted by a substantially V-shaped curved bar 11, the two branches of which support rollers 12 capable of rotating.

freely around the bar 11.

  The ends of the bar 11 are welded to the tubes 6.

  As seen in Figure 2, the ladder is applied against the post by its bearing surface 10, and more precisely by its rollers 12, which, while being able to roll along the pole, facilitate the positioning of the ladder and possibly its deployment avoiding the wear of the bearing surface 10 against the post, which is especially advantageous when the

post is made of cement.

  It is understood that the V-shaped bar 11 and the ends

  curves of the arms 8 lead to the centering of the post with respect to the scale.

  A rope 13, knotted at 14 so as to comprise two strands 15a and 15b, is connected to each of the arms 8 by means of rods 16 which are each articulated on an axis 17 welded below

  each arm, at a distance of about 10 cm from the corresponding sheath 7.

  Each strand 15a, 15b of the rope is guided in an eyelet 18 which is formed on a rod 19 parallel to the curved bar 11, welded to

  its ends on the two tubes 6 and in its middle to the curved bar 11.

  In the position shown in Figure 2, it is understood that when pulling the rope 13 downwards, it causes the tightening of both

arm 8 around the post 1.

  In Figure 3, the safety device 5 is shown with its arms 8 retracted, that is to say that the arms 8 are in position

  open and are folded on the opposite side of the ladder to the post 1.

  In this position of the arms 8, the ladder can be applied against the post 1 by its rollers 12, which facilitate the sliding

  from the top of the ladder against the pole.

  To move from the closed position shown in FIG. 2 to the open position of FIG. 3, each arm 8 pivots about 320 in the direction of its opening, that is to say, with respect to FIG. counterclockwise for the arm corresponding to the upright 2a and clockwise for the arm

corresponding to the amount 2b.

  During this pivoting, each strand 15a, 15b of the rope 13

  wraps around the vertical branch of the corresponding arm 8.

  Thanks to the presence of the links 16, the strands 15a and 15b wound around the vertical branches of the arms 8 do not overlap, which makes it possible to avoid the friction of the rope on itself, friction which

  could lead to rope wear and arm lock 8.

  Once the ladder is properly put in place, we exercise a

  pulling on the rope 13, which causes the arms 8 to pivot.

  Given that each strand 15a, 15b of the rope 13 is wound directly on the vertical leg of the corresponding arm 8, the torque exerted by the rope on each arm is relatively small compared to the tension exerted on the rope, but sufficient to allow the deployment of said rope, and this thanks to the links 16 which

  eliminate any risk of friction of the rope on itself.

  After turning about a half turn, the arms 8 reach

  the position shown in Figure 5.

  The strands 15a and 15b of the rope are then entirely

  unrolled and stretched between the link 16 and eyelet 18 corresponding.

  The pivoting of the arms 8 is interrupted when they reach their closed position in which they are tightened around the

post 1.

  It may be noted that at this stage of the establishment of the arms, the rods can avoid rubbing the strands 15a, 15b against the pole, which is advantageous especially when it is a concrete post. To immobilize the arms in the closed position, the user stretches the rope 13 along the ladder and attaches it to the lower part of the ladder. It should be noted that, according to the invention, it is not necessary for the rope to be perfectly tensioned between the two ends of the ladder 6 - but it is sufficient that it be attached at the bottom of the ladder so as to do not go back up with the user when the user climbs up the ladder and prevents the arms from opening to resume their open position. The rope can therefore be a little loose, the arms are then not tightly close to the post but held in a position in

  which they enclose the pole against the support range.

  To lock the rope at the bottom of the ladder, it is possible to use a blocker 20 secured to one of the bars of the ladder, as

see it in figure 8.

  The blocker 20 prevents the rope from rising but allows its

sliding down.

  The ladder is thus applied against the pole with his arms

surrounding said post.

  It should be noted that the operations described so far are performed by the user from the ground, which preserves it from all

risk of falling.

  To use the ladder, the user wears a harness or a belt (not shown) that connects to a self-locking handle 21, shown in Figure 7, which is engaged on the rope 13 so as to be able to freely mount along this rope and to hang on said

  rope when dragged down.

  In FIG. 7, there is shown in broken lines a

  locking mechanism of the self-locking handle on the rope 13.

  It is understood that when the carabiner 22 drives the latch 23 downwards, the jaw 24 comes to grip the rope 13, which immobilizes the

  self-locking handle 21 on said rope 13.

  Thus, the user can ride freely along the ladder,

  using the rope as the lifeline.

  In the event of a fall or imbalance, the self-locking handle stops on the rope and the user, who is thus held by the rope, exerts on this rope a traction which accentuates the tightening of the rope.

arm 8 around the post 1.

  The rope 13 can then exert a maximum torque on the arms 8 because the rods 16 and the strands 15a, 15b extend substantially

  perpendicular to the horizontal branches of the arms 8.

  In this way, the scale 2 remains in position, which allows a

the user to recover.

  -7- As already explained, we see that it is not necessary for the user to perfectly stretch the rope before climbing to scale. It suffices for the arms of the safety device to surround the post so that the action of the rope on the arms, in the event of a fall of the user, causes the solid attachment of the upper part of the

the ladder to the pole.

  It is understood that the embodiment which has just been described is not limiting in nature and that it can receive all

  desirable modifications without departing from the scope of the invention.

  In particular, it has described here a pole of electrical son, but it is clear that the invention could be applied to any substantially cylindrical support against which one is led to support a ladder.

- 8 -2740507

Claims (8)

  Safety device for ladder, characterized in that it comprises in combination two pivoting arms (8) mounted on the upper part (3) of the ladder (2), able to assume an open position in which they leave between them a space sufficient for the passage of a pole (1) and a closed position in which these arms are tight against said post (1), a rope (13) connecting said arms to the lower part of the ladder (2) ) to exert on the arms (8) a force which tends to cause their closure when this rope is pulled down, said rope serving as a lifeline comprising a self-locking sliding handle (21) to which can be connected a harness worn by the user of the ladder.   2. Device according to claim 1, characterized in that the arms (8) in the open position are brought completely on the face of the scale which is not applied against the post (1) so as to limit clutter of the upper part (3) of the ladder (2) during   its positioning against the post (1) or against a tree.   3. Device according to any one of claims 1 and 2,   characterized by the fact that the arms (8) move from their open position to their closed position when pulling the rope (13) towards the lower part of the ladder (2), while springs, preferably helical, act on the arms (8) to bring them back constantly into open position.   4. Device according to any one of claims 1 to 3,   characterized by the fact that the arms (8) are articulated in the vicinity of one of the uprights of the ladder each around a substantially vertical axis   when the ladder (2) is in use position.   5. Device according to claim 4, characterized in that the rope (13) is connected to each arm (8) at a point of this arm located   about 10 cm from its pivot axis.   6. Device according to any one of claims i to 5,   characterized in that it comprises a bearing surface (10) slightly curved substantially at the height of the two arms (8), thanks to which   the ladder (2) can lean against the post (1).   7. Device according to claim 6, characterized in that the bearing surface (10) comprises rollers (12) capable of rolling along the pole (1) to facilitate the introduction and possibly the deployment of the scale (2). - 9 - 2740507   8. Scale, characterized by the fact that it comprises a   safety device according to one of claims 1 to 7.