GB2473284A

GB2473284A - Mobile fall prevention assembly with twin booms

Info

Publication number: GB2473284A
Application number: GB0915667A
Authority: GB
Inventors: Anthony Carden
Original assignee: SHIRE 4 EDUCATION Ltd
Current assignee: SHIRE 4 EDUCATION Ltd
Priority date: 2009-09-08
Filing date: 2009-09-08
Publication date: 2011-03-09
Also published as: GB0915667D0

Abstract

A fall arrest assembly 10 has two booms 17 which cooperate to suspend a rail 24 to which safety lanyards 36 can be attached. The two booms are supported by first 16a and second (16b, figure 3) stanchions which are fixed to a common boom support structure such as a trailer 11 but which can be moved with respect to each other, preferably by extension of the trailer alongside a heavy goods vehicle to be unloaded. Folding sections (40a, 40b, figure 2) of the support structure may accommodate the change in length and can be locked in position. The booms pivot 20a on the stanchions so that they can be raised or lowered. The trailer can include ballast tanks 28 and an access platform 30 that can be raised up to the height of a vehicle being unloaded. The safety lanyards may extend from a drum with a rate-dependent centrifugal brake.

Description

Title: FaU-arrest assembly ritionofinvenUon This invention relates to a faflarrest assembly, particularly but not exclusively for arresting a fall from a vehicleload platform.

It is required that a person working at height, for instance on a building construction site must be provided with safety apparatus capable of arresting the fafl of that person in the event of an accident. This is also the case where a person loads or unloads construction materials from a vehicle load platform such as a lorry trailer. It is common for such safety apparatus to comprise nets, supported below the working height However, this method is of no use where personnel are required to climb on top of loads, for example to attach a crane hook to the load, as the height ef the load may be sufficient to cause injury in the event of a fall.

It is known to provide a system in which a safety harness is attached to a wire by way of a lanyard, wherein the wire is suspended across the work area at a fixed height. HoweveL this method is not suitable when loading or unloading a platform using a crane, as there is a high risk of the crane interfering with the wire It is also known to provide a harness connected to one or more lanyards that are suspended from fixed points above the load platform, but the downfalls of such a system are that the movement of the user is significantly impaired and the user may be swung between the fixed points in the event of a fall, and collisions with the load, the platform, or even the crane, may cause serious injury.

It is an object of the present invention to address, or reduce, the above problems.

According to a first aspect of the invention, we provide a fall-arrest assembly for arresting the fall of a user, the assembly comprising a first and.a second boom assembly supported on a boom support structure, and fall-arrest means for restraining a user, the boom support structUre including a first body and a second body, the first boom assembly being supported on the first body and the second boom assembly being supported on the second body, the first and second bodies being moveable relative to one another, wherein the fall-arrest assembly is configurable such that the first and second boom assemblies are 1:0 spaced one anotherfor supporting the fall-arrest means.

The first body and the second body may be connected to one another by a joining structure The joining structure may comprise at least a first and a second body-connecting element, and the first and second body-connecting elements may be pivotably connected to one another.

The joining structure may be provided with locking means for holding the first and second body-connecting elements in position relative to one another.

Each boom assembly may include an arm element which is pivotably connected to an upright support element of a respective boom support structure, so as to allow the arm element to pivot between a first position in which the arm element is upwardly inclined from the boom support structure and extends beyond a first side of the support structure and a second position in which the boom arm extends generally upright from the boom support structure.

The arm element may be moveable to a third position in which the arm element is upwardly inclined from the boom support structure and extends beyond a second side of the support structure, the second side being the side opposite to the first side.

The fall-arrest means may include an elongate support element which extends between, and Is supported on, the first and second boom assemblies. The elongate support element may be a rigid rail.

The fafl-arrest means may include a lanyard for supporting the user.

The lanyard may be secured to the elongate support element by way of a securing mechanism, the securing mechanism being moveable lengthwise relative to the elongate support element, The secunng mechanism may be provided with a release mechanism which is operable to release the lanyard from the securing mechanism.

The securing mechanism may provide a recoiling mechanism to cause the lanyard to recoil when the lanyard is not taut, and the securing mechanism may compnse a drum which includes a centnfugal brake for providing resistance to the extension of the lanyard from the drum when a change in the rate of extension of the lanyard from the drum exceeds a predefined level.

The boom-support structure may include support legs for stabilising the fall-arrest assembly.

The boom-support structure may include a platform which lies along at least a portion of the length of the boom-support structure.

Each set of wheels may include a braking means.

Embodiments of the invention will now be described by way of example only with reference to the accompanying drawings, of which: Figure 1 is a front view of a fall-arrest assembly in accordance with the first aspect of the invention; Figure 2 is a side view of a boom support structure of a fall-arrest assembly, shown In a contracted configuration; Figure 3 is a side view of the boom support structure of Figure 2, shown in an extended configuration; Figure 4 is a plan view of the fall-arrest assembly of Figure 1 Referring now to the drawings, a fail-arrest assembly 10 is shown, incuding a pair of boom assemblies I 7a, I 7b supporting a fall-arrest means 23, the boom assemblies 17a, 17b being supported on a boom-support structure 11 in this case, the boom-support structure 11 is a vehicle trailer suitable for being towed by a vehicle such as a van, or the like.

The boom-support structure 11 includes a first body 12a and a second body 12b, each body comprising a deck structure ISa, 13b on which au upright support structure 16a, 1Gb is connected, respectively. Each deck structure 13a, 13b is supported on a set of wheels 14a, 14b, and may provide a means to connect a tow bar, or the like, to allow the body to be towed by a vehicle In this example, the fall-arrest assembly 10 is shown alongside a trailer of a lorry, wherein the body 12a is positioned alongside the trailer, so that only a small lateral gap exists between the two, It should be noted that the height of the deck structure I 3a is lower than that of the trailer, and not at such a height that a fail-arrest system is required for a user to work thereupon. Each set of wheels 14a, 14b may be provided with a braking means, which may be applied to the wheels to hold them stationary.

A platform 30 is supported by platform support elements 32, which are connected between the platform 30 and the deck structure 1 3a, so to hold in place and reinforce the platform 30. The platform 30 provides a surface on which a user may stand, and its height may be adjusted by repositioning or reconfiguring the platform support &ements 32 as appropriate. Preferably, the platform 30 is adjusted so that its height coincides approximately with that of the trailer, or other load surface, next to which it is positioned.

Ballast elements 28 are deployed on the deck structure 13a in order to prevent the body 12a from tipping to one side or the other under a force such as a direct load or rotational moment. The ballast elements 28 may be water tanks which can be filled and emptied on site, thus providing a significant weight to the body when deployed, yet not adding a significant amount to the weight of the body when emptied Alternatively the ballast elements may be any form of ballast including sand tanks, concrete blocks, or the like.

An upright support structure iSa, 1Gb is upstanding from each deck structure 13a 13b, to which a respective boom assemb'y ha, 17b is pivotably attached about respective pivot means 20a 20b positioned at the upper end of each support structure 16a, 16b. Each boom assembly 17a comprises an arm element I 8a, having an upper end I 9a, lower end 21 a, and an upright portion 22a pivotably connected about an elbow 26a disposed at the upper end I9a of the arm element 18a, from which the upright portion 22a extends downwardly Having a pivotably connected arm element 18a, 18b, the boom assembly 17a, 17b may be adjusted to the required position to accommodate a variety of load-heights on the load platform. Also, the boom assembly I 7a, I Tb must be able to pivot so that it does not lie over the load platform when a crane is to be operated over the load platform, thereby avoiding collisions between the two.

The lower end 21a of the arm element may be connected to t.he respective body 12a, 12b, on which it is supported, by boom-anchoring means 34. The boom-anchoring means 34 may comprise locking metallic arms which can be locked into a rigid position in which they prevent the lower end 21 a of the arm element 18a from moving, thereby preventing any part of the boom assembly 17afrom moving whilst in use. It will be apparent to a person skilled in the art that the boom-anchoring means 34 may take forms other than locking arms.

In this example, the pivot means 20a about which the upright support structure ISa and arm element 1 8a are connected to one another, allows the arm element I 8a to pivot about the horizontal axis, so as to increase or decrease the height of the upper end I 9a of the arm element I 8a In the embodiment shown, the arm element 18a comprises a single elongate arm structure, but it should be understood that the arm element may comprise a number of elongate sections attached to one another pivotably, or otherwise to allow the arm to be placed in different configurations The tall-arrest means 23 is supported by the two boom assemblies 17a, 17b, whilst the fall-arrest assembly is in use. In this example, the fall-arrest means 23 comprises an elongate support element 24, to which a securing mechanism 37 is attached, the securing mechanism 37 providing means to secure a lanyard 36 to the elongate support element 24 for supporting a user. The elongate support element 24 is a rigid rail, capable of comfortably supporting the weight of a user. The securing mechanism 37 may be fixed relative to the elongate support element 24 or may bo moveable thereon to allow a user to move lengthwise along the load platform Preferably, the elongate support element 24 lies along the entire length of the load platform, so as to allow a user to move to any point on the load platform.

The elongate support element 24 is connected to the lower end of the upright portions 22a 22b of the arms of the respective boom assemblies 17a, 17b, such that the load placed on the elongate support element 24 is spread between the boom assemblies ha, 17b. When deployed for use, the boom assemblies 17a, 17b are spaced from one another, and preferably the elongate support element 24 is approximately the same length as the length of the loading platform above which it is being deployed, so that the elongate support element 24 is supported at a position which is roughly one quarter of its length from each of its ends by the two boom assemblies 1 7a, 1 Tb, so as to spread the load relatively evenly between the two boom assemblies.

The securing mechanism 37 may be provided with a release mechanism to allow a user to attach or detach the lanyard 36 from the rest of the faH-arrest assembly 10. The release mechanism allows the user to detach himself from the boom assemblies I 7a, I Tb, so that when he has stepped from the load platform, the boom assemblies i7a, 17b may be pivoted to a different position, without affecting the user.

The securing mechanism 37 may also provide a recoiling mechanism to cause the lanyard to recoil to prevent slack from forming in the lanyard 36 whilst in use, which would be dangerous if the user were to fall, and may also impede the activity of the user.

Preferably, the securing mechanism 37 comprises a drum with a centrifugal brake which is activated in the event of a sudden increase in force on the lanyard 36 This provides an ideal falkarrest system for use on a raised platform such as a loading platform of a lorry trailer, because the lanyard will not merely lock in the event of the user falling, which could cause whip-lash injuries, or could cause the the user to swing against the side of the vehicle, or against the load. Instead, the centrifugal brake activates as the fall is in progress, and acts to dampen the extension of the lanyard so as to smoothly break or halt the fall. Of course, other fall-arrest means may be provided in addition to, or instead of, the fall-arrest means described herein by way of

example.

Referring now to figure 2, the first 12a and second 12b bodies comprising the boom support structure 11 are shown, including respective deck structures ISa, 13b, sets of wheels 14a, 14b, and upright support structures iSa, 1Gb.

Each boom assembly 17a, 17b (not shown) is pivotably connected to its corresponding upright support structure iSa, 16b. Additionally, a joining structure 18 is attached to the deck structures iSa, 13b of the respective bodies, comprising a pair of body-connecting elements 40a, 4Db connected to one another about a pivotable joint 42 The body-connecting elements 40a 4Db are preferably elongate ngid boches, formed from a metal such as steel It is advantageous for the fall-arrest assembly 10 to include a joining structure 38, as this enables the two bodies to remain connected to one another dunng use, thereby providing greater stabiiity. The fall-arrest assemb& 10 can be towed to a site as one combined body, and then extended to form a longer body, which allows the fall-arrest means 23 to be supported over a greater length of loading platform than would otherwise be possible.

As shown in figure 2, the first body-connecting element 40a is connected to the first body 1 2a by a hinged connection, and the second body-connecting element 4Db is connected to the second body 12b by a hinged connection.

This configuration, wherein the two bodies are adjacent one another, may be thought of as the transit configuration, as in this configuration the fall-arrest assembly may easily be towed to a required position The first 12a and second 12b bodies may have fastening means to fasten the first body 12a to the second body 12b, so that the bodies cannot move apart when in transit.

Figure 3 shows the first 12a and second 12b bodies spaced one another. in this position, the joining structure 38 connects the two bodies 12a, 12b As the bodies are moved away from one another, first 40a and second 4Db body- connecting elements pivot about the pitovabie joint 42, and each body-connecting element 40a, 4Db, pivots downwards about its hinged connection with its respective body 12a, 12b. When the bodies are spaced at the 3D preferred distance from one another, the joining structure prevents the bodies from moving further apart. At this point, the body-connecting elements 40a, 4Gb lie approximately horizontal between the bodies. The joining structure 38 may further indude locking means for holding the body-connecting elements 40a, 4Gb in this formation, which ensures that the two bodies cannot move relative to one another once deployed, thus providing a solid base for supporting the boom assemblies 17a, 17b. This configuration, wherein the tirst body 12a and second body 12b are spaced one another, may be thought of as the "deployed configuration Whilst in the deployed configuration sets of support legs 44a, 44b may be utilised to further support each body 12a, 12b, respectively. The support legs 44a, 44b may be separate components which are attached to the respective body 12a, 12b to prevent the body moving, and to further enhance the strength and stability of the fall-arrest assembly Alternatively) the support legs 44a, 44b, may be connected to the respective body 12a, 12b, and moveable into position when required. Of course, whilst support legs 44a, 44b provide an effective method of stabilising the boom support structure 11, Other support structures may be used. Such structures may or may not be extensible from the bodies 12a, 12b of the boom support structure 11.

In an alternative embodiment of the invention, the joining structure 38 may comprise a unit that is separate from the first 12a and second 12b bodies, and is connected to the first body I 2a and second body I 2b once the bodies have been moved so as to be spaced one another. In this embodiment, the joining structure may comprise one or more body-connecting elements which may be attached between the bodies.

Figure 4 shows a fall-arrest assembly 10 in its deployed configuration, alongside a load platform such as a load platform of a lorry trailer. In use, once a fall-arrest assembly 10 has been deployed, the support legs 44a, 44b, are positioned so as to provide support to each respective body 12a, 12b, and joining structures 38 are fully extended so as to connect the first 12a and second 12b bodies, such that the body-connecting elements lie approximately horizontal therebetween. Once deployed in this way, ballast elements 28 are placed on the deck structures 13a, 13b so as to anchor the respective bodies I 2a, I 2b. The boom assemblies 1 7a, I 7b are pivoted so that the main body of each arm element 18a, 18b is inclined upwardly from its respective pivot means 20a, 20b, so that the upper end 1 Ga., 1Gb of the arm element I Ba, 18b, and connected upright portion 22a, 22b is disposed over tne load platform In this example it can be seen that the upper end 19a, lOb of each boom assembly 17a, 17b is disposed in a position over the central midpoint of the width of the trailer, such that the elongate support element 24 of the fall-arrest means 23 lies lengthwise along the midpoint of the width of the trailer When the fall-arrest assembly 10 is in its deployed configuration, the platform may be erected along at least a portion of the length of the fall-arrest assembly 10. The platform 30 is supported on platform support elements 32 which may be a permanently-fixed structure on the deck structure 13a, 13b, or may alternatively be built on site once the fall-arrest assembly 10 has been deployed. The platform 30 may also be erected over the joining structure 38 between the first body 1 2a and second body I 2b, as is the case in the example shown in Figure 4, where the platform 30 runs the entire length of the fall-arrest assembly, and extends beyond the ends of each body 12a, 12b, and from the side of the bodies so as to at least partly bridge the gap between the fall-arrest assembly 10 and the load platform:. The platform 30 provides a stable structure on which a user may stand if the user needs to leave the load platform for any reason.

For example, where a user works on a load platform to connect the hook of a crane to loads on the platform, it is not safe for the user to remain on the load platform whilst the crane operates to lift the load from the platform. Once the loads have been connected to the hook of the crane, the user leaves the load platform and moves on to the platform 30, which is provided in close proximity.

Before the crane is able to lift the load, the arms 18a, I8b of the boom

N

assembhes 17a, 17b may pivot so that the faU-arrest means 23 is no longer positioned over the load platform, therefore avoiding colHsions between the crane and the fall-arrest assembly 10.

In the above examples, the thU-arrest assembly 10 is shown relative to a single load platform but it may instead be deployed between a first and a second load platform The boom assemblies 7a, fib allow pivotable movement of the arm elements ISa, 18b, which allows the arm elements iSa, l8bto extend from either side of the boom-support structure Ii as appropriate. A gap ahgned with each upright support structure IGa, 16b may be left when the platform 30 is erected, so that the lower ends 21a, 21b of the arm elements 18a, 18b are not obstructed when the arm pivots from one side to the other.

Furthermore, the elbow 26a, 26b of each boom assembly iTs, i7b may comprise a knuckle formation which allows the upright portion 22a, 22b of each arm element 18a, 18b to pivot about the arm element so that when the boom is moved from one side to the other, the upright portion 22a, 22b may adopt a position disposed below the upper end Wa, 19b of the arm element 18a, I 8b no matter which side the boom assembly I Ta, I Tb is placed.

In use, the fall-arrest assembly 10 may be towed! whilst in its transit configuration (the first 12a and second 12b bodies connected to one another)! by a vehicle, to the place where it is to be deployed. The braking means may then be applied to the set of Wheels 14b on the second body 12b so as to hold the second body 12b stationary. Once the brake has been applied, the vehicle may drive forward so as to pull the first body 12a forward, causing the joining structure 38 to extend, the body-connecting elements 40a, 40b pivoting about the pivotable joint 42 until they extend approximately horizontally between the bodies. Once the joining structure 38 is fully extended, the braking means is applied to the set of wheels 14a on the first body 12a. Now in its deployed configuration, the ballast elements are filled oil the deck structures ISa,, 13b of the two bodies, the support Legs 44a, 44b are deployed, and the platform 30 may then be erected on the boom-support structure 11 The arm &ements 17a, ilb of the boom assemblies 18a, 18b may then be pivoted into position, and the boom-anchoring means 34 attached to the lower ends 21 a, 21 b of the arm elements 1 8a, 18b. The fall-arrest means 23 may then be attached to the upnght portions 22a, 22b of the boom assemblies I la, I 7b Because the lanyard 36 is supported from the secunng mechanism 37 which is moveable lengthwise on the elongate support element 24, the fall-arrest means 23 may be used over a portion of the length of the loading platform, limited only by the length of the elongate support element 24.

Therefore, if the elongate support element 24 lies along the entire length of the load platform, the user may move freely along its entire length It is possible that the fall-arrest assembly may be used by more than one user simultaneously. To enable multiple users to use the equipment, each user is provided with a separate lanyard, and each lanyard is attached to the elongate support element by a separate securing mechanism.

When used in this specification and claims, the terms "comprises" and "comprising' and vanations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropnate, may separately, or in any combination Qf such features, be utflised for ealising the invention in diverse forms thereof.

Claims

-13 -CLAIMS1. A fall-arrest assembly for arresting the faD of a user, the assembly comprising a first and a second boom assembly supported on a boom support structure, and fall-arrest means for restraining a user, the boom support structure including a first body and a second body, the first boom assembly being supported on the first body and the second boom assembly being supported on the second body, the first and second bodies being moveable relative to one another, wherein the fall-arrest assembly is configurable such that the first and second boom assemblies are spaced from one another for supporting the fall-arrest means.
2. A fall-arrest assembly according to claim 1, wherein the first body and the second body are connected to one another by a joining structure.IS
3. A fall-arrest assembly according to claim 2, wherein the joining structure comprises at least a first and a second body-connecting element, and the first and second body-connecting elements are pivotably connected to one another.
4. A faD-arrest assembly'according to claim 3, wherein the joining structure is proVided with locking means for holding the first and second body-connecting elements in position relative to one another.
5 A fall-arrest assembly according to any one of the preceding claims wherein each boom assembly includes an arm element which is pivotably connected to an upright support element of a respective boom support structure, so as to allow the arm element to pivot between a first position in Which the arm element is upwardly inclined from the boom support structure and extends beyond a first side of the support structure and a second position in which the boom arm extends generally upright from the boom support structure.
6. A fall-arrest assembly according to claim 5, wherein the arm element is moveable to a third position in which the arm element is upwardly inchned from the boom support structure and extends beyond a second side of the support structure, the second side being theside opposite to the first side.

7 A fall-arrest assembly according to any one of the preceding claims wherein the fall-arrest means includes an elongate support element which extends between, and is supported on, the first and second boom assemblies 8. A fall-arrest assembly according to claim 7 wherein the elongate support element is a rigid rail., A fall-arrest assembly according to claim 8 or claim wherein the fall-arrest means includes a lanyard for supporting the user.10. A fall-arrest assembly according to claim 9 wherein the lanyard is secured to the elongate support element by way of a secunng mechanism, the securing mechanism being moveable lengthwise relative to the elongate support element.11. A fall-arrest assembly according to claim 10, wherein the securing mechanism is provided with a release mechansm which is operable to release the lanyard from the securing mechanism.I 2. A fall-arrest assembly according to claimS 10 or claim 11, wherein the securing mechanism provides a recoiling mechanism to cause the lanyard to recoil when the lanyard is not taut.13. A fall-arrest assembly according to any one of claims 10 to 12, wherein the securing mechanism comprises a drum which includes a centrifugal brake for providing resistance to the extension of the lanyard from the drum when a change in the rate of extension of the lanyard from the drum exceeds a predefined level.14 A fall-arrest assembly according to any one of the preceding claims, wherein the boom-support structure includes support legs for stabilising the fall-arrest assembly.A fall-arrest assembly according to any one of the preceding claims, wherein the boom-support structure includes a platform which lies along at least a portion of the length of the boom-support structure.16. A fall-arrest assembly according to any one of the preceding claims, wherein each set of wheels includes a braking means.