EP2021574B1

EP2021574B1 - A system and anti-fall protection for individuals using ladders

Info

Publication number: EP2021574B1
Application number: EP07722608A
Authority: EP
Inventors: Søren MIDTGAARD
Original assignee: Avanti Stigefabrik AS
Current assignee: AIP ApS
Priority date: 2006-05-16
Filing date: 2007-05-14
Publication date: 2010-05-05
Anticipated expiration: 2027-05-14
Also published as: WO2007131508A1; DE602007006301D1; ES2345850T3; DK177726B1; DK200600685A; EP2021574A1; ATE467032T1

Abstract

The invention relates to a system for anti-fall protection of individuals during work on ladders with rungs. The system comprises an anti-fall protection with a first and a second side and a displaceable hinge that can be secured to an individual by means of safety line, harness or the like, and a rail for attachment in an essentially vertical position on or at the ladder. The anti-fall protection and the rail has co-operating locking means that are adapted to be such that the anti-fall protection can slide on the rail when the rail is displaced in one direction and is securely locked onto the rail when the hinge is displaced in another direction. Rail and anti-fall protection are also configured with complementary and asymmetrical engagement means to the effect that the anti-fall protection can be mounted on the rail with only one side upwards, and said first and second sides being mutually displaceable to the effect that the engagement means can be caused to disengage from the rail. Between the first and the second sides, the anti-fall protection also comprises connection means that cooperate with the hinge to the effect that the first and second sides of the anti-fall protection can be shifted out of engagement with the rail only when the hinge is displaced in one direction.

Description

The invention relates to a system for protecting individuals during work on ladders with rungs, which system encompasses anti-fall protection that comprises a first and a second side and a displaceable hinge that can be secured to an individual by means of a safety line, safety harness or the like and a rail for being attached in an essentially vertical position on or at the ladder; said anti-fall protection and rail having cooperating locking means that are adapted such that the anti-fall protection is able to slide on the rail when the hinge is displaced in one direction, and is secured on the rail when the hinge is displaced in another direction, said rail and anti-fall protection being also configured with complementary and asymmetrical engagement means such that the anti-fall protection can be mounted on the rail with only one side up, and wherein said first and second sides can be displaced relative to each other to the effect that the engagement means can be caused to engage and disengage the rail.
When work is to be performed at great heights, eg during maintenance of wind turbines, it is often required that the person at work stands for long durations on internal or external ladder structures. This is due to the fact that, on the one hand, the person performing such tasks is often to climb long distances on the ladders and, on the other hand, some of the work is also to be performed while standing on the ladders. The ascending and descending being in particular associated with physical strain, there is an increased risk of errors due to exhaustion and there is there for a need for equipment that is not only reliable, but also unfailing and easy to operate and which may provide safety against individuals falling.
Equipment for anti-fall protection is known which is used in connection with eg work on ladders. Such equipment usually comprises a anti-fall protection which is able to slide on a rail intended therefor. The anti-fall protection usually comprises a brace or a hinge which, via eg one or more snap hooks and a safety harness, can be connected to the worker who uses the equipment. This kind of anti-fall protection functions in that the anti-fall protection slides on the rail at the rates and accelerations that occur in case of normal use of the ladder and, in return, locks securely onto the rail at the rates and accelerations that usually occur in case of a fall. Often the underlying mechanical principle of these anti-fall protection systems is based on an eccentric mechanism accommodated at the bottom of the brace or the hinge which is rotatably journalled. The eccentric mechanism functions in that it is forced into locking engagement with the rail when the brace or the hinge is influenced relatively by a downwards force. When the anti-fall protection is used by a person who climbs the ladder, the hinge thus occupies such position where the eccentric is released from the rail, whereas a fall will influence the brace or the hinge in a direction where the eccentric engages lockingly with the rail.
DE 20314230 U1 shows a system according to the preamble of claim 1 and an anti-fall protection according to the preamble of claim 3.
From US patent application No. US 2003/0217887 a system is known for securing individuals against falls. The system comprises an anti-fall protection provided with brace/hinge which is mounted on a rail configured therefor. The anti-fall protection allows the individual using it to move up and down in case of normal use of the ladder, but in case an individual using the system slides or falls, the slider instantly locks onto the rail. The anti-fall protection functions by means of an eccentrics mechanism as described above which is connected to the hinge or the brace and which, when the hinge/brace is influenced by a sufficient force in a downwards direction, is forced to lockingly engage the associated rail. To prevent faulty orientation of this anti-fall protection on the rail to the effect that, instead of preventing quick movement in downwards direction, it allows same, the rail and the anti-fall protection are adapted such to each other that the anti-fall protection can be oriented on the rail in only one way.
US patent No. US 6,725,969 B1 discloses another system for safeguarding against falls from ladders. This system also comprises an anti-fall protection which, during use of the ladder, has to be mounted on a rail. That anti-fall protection functions by means of a latch/pawl which is forced into engagement with holes intended therefor if the individual using the anti-fall protection falls.
Neither of those anti-fall protections can be mounted or dismounted just anywhere on the rail; rather they have to be mounted or dismounted at the top or at the bottom of the rail. This is inconvenient in case of large and complex structures such as eg. wind turbines. As it is, in those structures, there is often a need to be able to leave the ladder on the way, wind turbines often having landings and apparatuses at several different levels.
There is therefore a need for an anti-fall protection which allows dismounting and mounting anywhere on the rail and which is simultaneously safe against unintentional opening to the effect that the slider cannot fall off the rail.
Besides, there is a need to ensure that the anti-fall protection does not disengage the rail while it is preventing an individual from falling.
Experience has shown that exhausted people may act irrationally, such as open an anti-fall protection unintentionally. Experience has also shown that, provided an individual is to perform three logical/conscious acts to obtain a specific effect, it is very likely that the individual obtains that effect unintentionally. By thus providing an anti-fall protection with means to allow it to be dismounted only after three conscious acts have been performed, the risk of opening/maloperating is reduced considerably and hence there is a very high degree of reliability against an even very exhausted user unintentionally opening and/or dismounting the anti-fall protection.
The object of the invention is accomplished by a system according to claim 1.
According to one embodiment the anti-fall protection, latch, ladder and rail are adapted to each other to be such that the latch will hit the rungs of the ladder when the anti-fall protection is mounted on the rail, and the latch occupies the position in which it allows a movement of the stop means to enable it to occupy a position where the hinge can be moved to a position in which the first and the second sides can be shifted out of engagement with the rail.
By adapting anti-fall protection, latch, ladder and rail to each other in this way it is prevented that the anti-fall protection is unable to slide on the rail and hence becomes useless in practice if just one of the three required actions is performed. This entails an increased degree of safety as the system is more or less self-controlling.
The invention further relates to an anti-fall protection as featured in claims 3-4.
It should be emphasized/stressed that the designation 'hinge' comprises any kind of displaceable mechanism to which an individual is able to secure a line.
In the following the invention will be described in further detail with starting point in the figures, where

Figure 1 is a perspective view of an anti-fall protection on which a rail is mounted;
Figure 2 is a perspective view of an anti-fall protection in a partially exploded view;
Figure 3 is a perspective view of an anti-fall protection as shown in Figure 1 in a partially exploded view, from another angle;
Figure 4 shows an anti-fall protection as shown in Figure 1 with its latch in pressed-in position;
Figure 5 shows the anti-fall protection shown in Figure 4 with mounted and pressed-in latch;
Figure 6 shows the anti-fall protection shown in Figure 3 with mounted and pressed-in latch, where the hinge is turned forwards to the position where the sides can be pulled apart;
Figure 7 shows a latch seen from the side.

An embodiment of the invention will now be explained in further detail with reference to the figures.
Figure 1 is a perspective view of an anti-fall protection 1 on which a rail (2) is mounted. The anti-fall protection comprises a first and a second side 10, 11 and a displaceable hinge 12, to which an individual can be secured by means of a safety line, safety harness or the like (not shown). The system further comprises a rail 20 for attachment in an essentially vertical position on or at the ladder (not shown either). Anti-fall protection 1 and rail 20 are configured with co-operating locking means that are adapted such that the anti-fall protection is able to slide on the rail 20 when the hinge 12 is displaced in one direction and locked onto the rail 20 when the hinge is displaced in another direction. In the case shown in Figure 1, the locking means are constituted by an eccentric 15 at the bottom of the hinge 12 which can be forced downwards towards the ladder 20 when the anti-fall protection is mounted on the rail, and the hinge is turned about the axis 18. The rail 20 and the anti-fall protection are also configured with complementary and asymmetrical engagement means 13, 14 and 21, 22 which, in the shown case, are constituted by flanges 21, 22 on the rail and cavities 13, 14 configured therefor in the anti-fall protection. On the rail as such there is, on the one side, configured a longitudinally extending edge 23 that fits into a corresponding recess in the one cavity 13 of the anti-fall protection (best seen in Figure 2). That edge 23 and the associated recess 16 ensure that the anti-fall protection can be mounted on the rail in only one way. The anti-fall protection is constructed such that the two sides 10 and 11 can be shifted in such a way relative to each other that the cavities 13, 14 can be pulled off the flanges of the rail and thereby the anti-fall protection can be mounted and dismounted anywhere on the rail. In the shown case, this functionality is obtained la through the use of a guide 17 on which the part 10 can be mounted slideably by means of an opening 18 corresponding to the guide.
To prevent that the anti-fall protection is unintentionally dismounted from the rail, the technical means that connect the first 10 and the second side 11 of the anti-fall protection are configured such that the side can be shifted out of engagement with the rail 20 only when the hinge 12 is in a specific position.
This functionality will now be explained in further detail with reference to figures 2 and 3.
In Figure 3, on the right side 10 of the anti-fall protection, an opening 40 will appear which is, to the right of the Figure, round and, further into the side 10, it proceeds to assume a substantially square shape. The square part of the opening 40 extends such distance into the side 10 that the corresponding head 41 on the shaft 19 allows a relative and axial movement between the shaft 19 and the side 10 when the head is in the square part of the opening 40. When the shaft 19 is to be mounted on the anti-fall protection, it takes place by firstly pulling its thin part through the opening 40 and then (turnably fixating it) through the hinge 12 in order to finally secure it in the other side 11 of the anti-fall protection. This attachment takes place by means of rivets 30, 31 (shown in Figure 2) that are able to engage with a corresponding recess in the one end of the shaft when the latter is introduced into the other side 11 of the anti-fall protection, and the rivets 30, 31 are mounted in holes configured therefore (not shown) underneath the openings 31a and 32a (as are shown in Figure 3). The length of the shaft 19 is adapted such to the anti-fall protection that the head 41 is located in the round part of the hole 40 when the anti-fall protection is mounted on the rail 20, and thereby a rotation of the shaft is allowed an hence also of the hinge 12 when the anti-fall protection is used on the rail. In order to dismount or mount the anti-fall protection to/from the rail, all it takes is thus that the hinge is turned to a position where the square head of the shaft is able to slide into the corresponding square part of the hole 40, following which the side 10 can be displaced relatively relative to the side 11, the head now being able to side into the square part of the hole 40. Besides, in the examples shown in the figures, the anti-fall protection is secured against the sides being entirely dismounted, the internal diameter 42 of the hole 40 (best seen in Figure 2) being of such size and shape that the head 41 is unable to pass there through.
Other embodiments of the invention will now be explained with reference to figures 4 and 5.
Figure 4 shows an embodiment of the invention where the hinge is shifted to a position where the eccentric mechanism 15 (not shown in Figure 4) is not in engagement with the rail, but wherein the sides 10 and 11 can be shifted mutually to the effect that the anti-fall protection can be dismounted from and mounted on the rail 20. Figure 5 schematically shows how the anti-fall protection further comprises a stop means which, in its shown position, allows the hinge to be moved to the position where the anti-fall protection is able to slide on the rail and simultaneously be dismounted from or mounted on the rail. This stop means 32 is journalled rotatably on a shaft 34 and the shop means comprises an edge 32 (shown in Figure 3) which is able to lockingly engage with a corresponding edge 33 on the hinge (also shown in Figure 3). In one embodiment, the shaft 34 of the stop means 32 is spring-biased such that the stop means seeks towards the position in which it prevents the hinge from turning towards the position in which the anti-fall protection can be separated from the rail. Thereby further preventive measures against the anti-fall protection being unintentionally dismounted form the rail 20 are provided.
According to a further embodiment, the hinge 12 can also be securely locked in engagement with the stop means 32, it being possible to fixate the stop means in this position by means of a latch 50. The latch 50 which is shown in greater detail in Figure 7 is, in this embodiment of the invention, mounted such - in the second side 11 of the anti-fall protection, as shown in figures 1 and 3 - that it can be displaced in its longitudinal direction. As will best appear from Figure 2, the latch has an area which is able to engage with an essentially flat piece 35 on the shaft of the stop means 32, and the length of the latch is adapted to be such that it takes place precisely when the latch is, as shown in Figure 1, pressed partially into the anti-fall protection. Thereby the stop means 32 is locked, which in turn locks the hinge 12 in a position where the anti-fall protection cannot be opened. As will appear from Figure 7, the latch further has an area 51 of reduced diameter and that area is adapted to the shaft on the stop means to enable the stop means to rotate when that part 51 of the latch is arranged opposite the shaft 35 of the stop means. By configuring the latch in this way and with a length ratio between head and narrowed potion suitable for the anti-fall protection, the latch allows rotation only when the latch is pressed completely into the anti-fall protection, as shown by figures 4 and 5. As will further appear, the anti-fall protection and the latch can be adapted to be such that the lower end 52 of the latch protrudes out through the underside of the anti-fall protection. It is the object of this that the end 52 of the latch - when the latch allows rotation of the stop means 32 - can and will hit the rungs of a ladder (not shown in the figuresl on which the rail 20 and anti-fall protection are mounted.

Claims

A system for protecting individuals during work on ladders with rungs, said system comprising an anti-fall protection (1) comprising a first (10) and a second (11) side and a displaceable hing (12) at can be secured to an individual by means of safety line, harness or the like, and a raill (20) for attachment in an essentially vertical position on or at the ladder; said anti-fall protection (1) and rail (20) having co-operating locking means that are adapted to be such that the anti-fall protection (1) is able to slide on the rail (20) when the hinge (12) is displaced in one direction and is locked on the rail (20) when the hinge (12) is displaced in another direction, said rail (20) and anti-fall protection (1) being also configured with complementary and asymmetrical engagement means (13,14,21,22) to the effect that the anti-fall protection (1) can be mounted on the rail (20) with only one side up, and said first and second sides being mutually displaceable to the effect that the engagement means can be caused to engage and disengage the rail the anti-fall protection also comprises between the first (10) and the second (11) sides connection means (19,41) that cooperate with the hinge (12) to the effect that the first (16) and the second (11) sides of the anti-fall protection (1) can be shifted out of engagement with the rail (20) only when the hinge (12) is shifted in one direction and installed in a specific position, said connection means (19,41) being configured such that the first (10) and second sides of the anti-fall protection (1) can be displaced out of engagement with the rail (20) only when the hinge (12) is displaced in the direction where it does not lock the anti-fall protection against the rail; and that the anti-fall protection (1) further comprises a stop means (32) allowing the hinge (12) to be moved to a position in which the anti-fall protection (1) is able to slide on the rail (20), prevents the hinge (12) from being moved to said specific position in which the first (10) and the second (11) sides can be shifted out of engagement with the rail, characterised in that said stop means (32) cooperating with a displaceable latch (50) to the effect that the latch (50) is to be taken to a predetermined position before the stop means (32) can be moved to a position where the first (10) and the second (11) sides can be shifted out of engagement with the rail (20).
A system for protecting individuals during work on ladders with rungs in accordance with claim 1, characterised in that anti-fall protection (1), latch (50), ladder and rail (20) are adapted such to each other that the latch (50) will hit the rungs of the ladder when the anti-fall protection (1) is mounted on the rail (20), and the latch (50) occupies the position in which it allows a movement of the stop means (32) to the effect that it may occupy a position in which the hinge (12) can be moved to a position where the first (10) and second (11) sides can be shifted out of engagement with each other.
An anti-fall protection (1) for use in a system with a rail (20) as defined in claims 1 or 2, comprising a first (10) and a second (11) side and a displaceable hinge (12) that can be secured to a person by means of a safety line, harness or the like, the anti-fall protection comprises between the first (10) and the second (11) sides connection means (19,41) that co-operate with the hinge (12) to the effect that the first (10) and second (11) sides of the anti-fall protection (1) can be shifted mutually only when the hinge (12) is displaced in one direction and installed in a specific position; and that the anti-fall protection (1) further comprises a stop means (32) that prevents the hinge (12) from being moved to a position in which the first (10) and the second (11) side can be shifted out of engagement with the rail, characterised in that said stop means (32) co-operating with a latch (50) to the effect that the latch (50) must be moved to a specific position before the stop means (32) can be moved to a position in which the first (10) and second (11) sides can be shifted out of engagement with the rail (20).
An anti-fall protection (1) according to claim 3, characterised in that latch (50), ladder and rail (20) are adapted such to each other that the latch (50) will hit the rungs of the ladder when the anti-fall protection (1) is mounted on the rail (20), and the latch (50) occupies the position in which it allows a movement of the stop means (32) to the effect that it is able to occupy a position in which the hinge (12) can be moved to a position where the first (10) and second (11) sides can be moved out of engagement with the rail (20).