IES20030704A2 - A fall arrest system - Google Patents

Abstract

A fall restraint or arrest system (1) is provided by a rigid safety rail (2) mounting a wheeled trolley (5). The trolley (5) is connected by a safety line to a safety harness (6). The safety rail (2) is not secured to the fabric of the building by both or other fasteners, but is connected to counterweights (3)which rest on the roof of the building. <Figure 1>

Description

Introduction This invention relates to a fall arrest system for mounting on the roof of an elevated structure of the type comprising a safety rail anchored with respect to the structure and a safety harness releasably secured to the safety rail.

The term structure is used to encompass, not only buildings, but other structures such 10 as partially built buildings, industrial plants, storage structures, and so on.

Nowadays, governments are introducing more comprehensive legislation to protect employees in the workplace and to provide a safer working environment for all workers. One such piece of legislation provides for employees working on tall structures and in particular on the roofs of tall structures in close proximity to the edge of the roof which often includes a relatively low upstanding parapet. Such raised parapets are a feature of most modern and indeed many old buildings. In this specification, the term parapet is used to refer to what are strictly parapets and to the edges of the building. As a result of this legislation, various safety systems have been 0 put in place to protect employees and to prevent them from accidentally falling off the roofs. One such known system is to provide a safety rail extending along the perimeter of the roof. However, these safety rails are often quite expensive to install as well as being unsightly.

Another safety system requires that all employees working within close proximity to a parapet must wear a safety harness anchored to the building so that in the event of an employee accidentally falling they will be restrained by the safety harness from going over the edge of the roof. Usually, a wire cable is secured to the building and the employee attaches their safety harness on to the wire cable. Various tensioners and anchorage points are secured to the roof of the building to secure the wire cable in position. There are, however, problems associated with this type of fall arrest system. The main problem associated with these systems is that the tensioners and anchorage points must be secured to the roof. This often involves puncturing the roof in many places. This is often undesirable as puncturing the roof may lead to water IE 03 07 0 4 ingress and other problems.

Therefore, it is an object of the present invention to provide a fall arrest system that overcomes at least some of the problems associated with the known types of fall arrest systems.

Statements of Invention According to the invention there is provided a fall arrest system for mounting on the roof of a' structure comprising a rigid safety rail comprising a track mounting a movable trolley for securing to a safety harness and associated safety lines and a plurality of anchoring counterweights for securing to the rail and for positioning and resting on the roof. By having such a fall arrest system there will be no need to drill holes into the roof of the building and puncture fabric of the building. The counterweights will act as sufficient leverage against the weight of a body falling. By having a rigid rail, no flexing of the rail is allowed and therefore the entire load is distributed across the entire rail. Such a system is relatively inexpensive and may be installed in a quick and efficient manner.

In one embodiment the track is channel shaped. By having a channel running along the length of the rigid rail the worker will be able to move along the rail unimpeded and will not have to constantly unhook and re-hook his harness into separate sections. Furthermore, this is particularly cost efficient to construct.

In another embodiment of the invention there is provided a fall arrest system in which the counterweight has a roof engaging base, the roof engaging base being covered in a non-slip gripping layer. It is envisaged that this non-slip gripping layer may be made from an elastomeric material. By having a non-slip layer additional friction against slippage is introduced into the system. This will further enhance the stability of the system preventing the fall arrest system from moving under a sudden load.

In a further embodiment of the invention there is provided a fall arrest system in which there are provided a plurality of spaced apart locators for engagement and disengagement of the trolley along the rail. By having a plurality of trolley locators IE 03 07 θ* along the rail the employee will be able to engage and disengage from the rigid rail in a number of different points and will not have to travel a significant distance to release themselves from the rail should they be permanently attached to the trolley member. These trolley locators will allow additional trolley members to be added to the rail without having to dismantle the rail.

In many instances, the trolley member is permanently retained in the track of the rigid rail. By having a trolley permanently retained in the track of the rigid rail there will always be a trolley available to use with the system. This will help avoid trolleys been lost or mislaid.

Alternatively, the trolley comprises a two part-body releasably secured together so that, on separation, the trolley may be removed from the track. In this way, additional trolleys may be added to the track at any point. By doing this several workers may use the rigid rail at the same time and will not have to switch harnesses should they need to cross over each other as one worker can simply dismantle their trolley and place it on the other side of the other employee’s trolley in the direction that they wish to go. in a further embodiment of the invention there is provided a fall arrest system in which the trolley is a wheeled trolley. Wheels provide a simple and easy sliding mechanism for the trolleys, which will be able to run in an unimpeded fashion.

In another embodiment of the invention there is provided a fall arrest system in which the rail comprises a box-like member comprising a base, mounting facing upstanding side walls, each terminating in an inwardly directed flange, the flanges forming an elongate re-entrant slot for reception of portion of the trolley therebetween, the interior of the base on both sides of the slot forming facing and spaced-apart trolley wheel engaging tracks and in which the trolley comprise a two-part body releasably connected together, one part carrying a trolley wheel for engaging one track and the other part carrying a trolley wheel for engaging the other track, the dimensions of the body and wheels being such as to retain the trolley within the rail when connected together and on disengagement, to allow withdrawal through the slot. ΙΕ ο 3 07 8 4 In one embodiment of the invention there is provided a fall arrest system in which the rigid rail comprises a plurality of rigid rail sections, each rigid rail section connected to another rigid rail section by way of a splice joint. By having a pair of different rigid rail sections connected by a splice joint the fall arrest system may be built in a modular manner. In this way the fall arrest system may be built up to suit the individual size of different buildings.

In another embodiment of the invention there is provided a fall arrest system in which the system further comprises a wall bracket support for reception and retention of one end of the rigid rail. Again, by having such a wall bracket support the roof of the building will not have to be punctured in many places. This is a safe and secure way of securing one end of the rigid rail of the fall arrest system and will provide extra stability to the system.

In a further embodiment of the invention there is provided a fall arrest system in which the system further comprises an end stop for connection to one end of the rigid rail to prevent inadvertent release of the trolley from the rigid rail. This will prevent unintentional release of the trolley from the rigid rail thereby protecting employees working adjacent the end of the rigid rail. It is furthermore simple and easy to insert into the rigid rail.

In one embodiment of the invention there is provided a trolley member for a fall arrest system of the type having an elongate rigid rail with a channel formed along its length, the trolley member comprising a body portion having a plurality of wheels mounted thereon, a retaining member for connection to a harness, the body portion being a two part body portion releasably secured together so that when the body portion is in a fixed configuration in the rigid rail, the trolley member is slidably secured in the rigid rail and when the body is in a separated configuration the trolley member may be removed from the rigid rail. By having such a trolley member several employees may use the same line of rigid rail at the same time and should one employee need to pass another employee on the rail they simply have to dismantle their trolley and place it on the opposite side of the rail to the other employees trolley in the direction in which they wish to travel. This will obviate the need for both of the employees to dismantle their harnesses and switch over trolleys. Another advantage of this construction of trolley IE 0 3 07 0 4 is that a single trolley may be used for several different sections of rigid rail.

In another embodiment of the invention there is provided a safety rail for a fall arrest system of the type having a safety rail anchored with respect to the structure and a safety harness releasably secured to the safety rail characterised in that the safety rail is a rigid rail mounted on a plurality of counterweights. Such a safety rail will obviate the need for puncturing the roof of a building and will be simple and efficient to install. Furthermore, by having such a rail, the weight of a falling individual will be distributed over the length of the rigid rail thereby providing a more robust and safer safety rail.

In a further embodiment of the invention there is provided a safety rail in which the rigid rail has a channel formed along its length for reception of a trolley member. This is seen as a particularly simple construction of safety rail that will be time and cost efficient to manufacture.

Detailed Description The invention will now be more clearly understood from the following description of some embodiments thereof given by way of example only with reference to the accompanying drawings in which:Ftg. 1 is a perspective view of the fall arrest system in operation mounted on the roof of a building; Fig. 2 is another perspective view of the fall arrest system of Fig. 1 showing a corner section and an end piece; Fig. 3 is a perspective view of a counterweight; Fig. 4 is a side elevation view of the counterweight; Fig. 5 is top plan view of the counterweight; Fig. 6 is a bottom plan view of the counterweight; IE 0 3 07 0 4 Fig. 7 is an end view of a rigid rail: Fig. 8 is an end view of a splice joint; Fig. 9 is a side view of the splice joint; Fig. 10 is an end view of an intermediate support bracket; Fig. 11 is a side view of the intermediate support bracket; Fig. 12 is a front view of an end stop; Fig. 13 is a side view of the end stop; Fig. 14 is a front view of a wall bracket support; Fig. 15 is a side view of the wall bracket support; Fig. 16 is a side view of a permanent trolley member; Fig. 17 is a front view of the permanent trolley member; Fig. 18 is a side view of a releasable trolley member; Fig. 19 is a front view of the releasable trolley member; and Fig. 20 is an exploded view of the releasable trolley member.

Fig. 21 is a side view of an alternative embodiment of releasable trolley member.

Fig. 22 is a front view of the releasable trolley member shown in Fig. 21.

IE OS 07 04 - 7 Referring now to the drawings and initially to Fig. 1 thereof there is shown a fall arrest system indicated generally by the reference numeral 1 for mounting on the roof of an elevated structure, the fall arrest system comprises a safety rail, namely a rigid rail 2 secured to a plurality of counterweights 3 positioned on the roof of the elevated structure. The rigid rail 2 comprises a plurality of rigid rail sections 2a connected together by splice joints 4. The rigid rail 2 has a channel (not shown) extending along its length for reception of a trolley 5, the trolley 5 being retained in the channel and slidable along the length of the channel. A safety harness 6, worn by an employee, is connected to the trolley 5 by way of a safety line 7.

Referring now to Fig. 2 of the drawings there is shown a corner section and one end of the rigid rail 2. The corner section comprises a curved rigid rail section 2b. This curved rigid rail section 2b is illustrated connected to a rigid rail section 2a by way of one of the splice joints 4. Additional counterweights 3 are connected to the end of the rigid rail 2 for additional stability.

Referring’ now to Fig.’s 3 to 6 inclusive there are shown different views of a counterweight 3. Each counterweight 3 is provided with a non-slip gripping layer 8 on its underside, in this case an elastomeric material such as rubber, to provide sufficient friction to prevent slippage of the counterweights under load. The counterweights 3 are typically constructed from steel or other similar heavy hard-wearing metallic material. However, many constructions could be used such as lighter metal plates and concrete blocks attached thereto. Indeed, the counterweights could be provided by loosely laid concrete slabs forming a base for the rigid rail sections. Similarly, any material may be used to prevent the counterweights slipping.

Referring now to Fig.’s 7 to 15 inclusive of the drawings where individual sections of the fall arrest system are shown in greater detail. Referring to Fig. 7, each rigid safety rail 2 is formed from the one sheet of metal to comprise a channel or U-shaped body portion comprising a base 9, facing upstanding side walls 10 cranked intermediate their ends at 10a terminating in inwardly directed flanges 11 forming a re-entrant slot 11a.

Fig.’s 8 and 9 show different views of the splice joint 4. The splice joint 4 is IE 0 3 07 04 - 8 constructed from a bent sheet of metal having a similar cross sectional profile for reception of the ends of two rigid rails 2. The slice joint 4 comprises a substantially Ushaped body portion 12 terminating at its ends in inwardly directed flanges 13. The internal dimensions of the splice joint 4 are such as to receive the rigid rails 2 therein. Fasteners, provided by threaded bolts 14 are additionally provided. In use, a pair of opposing ends of adjoining rigid rails 2 are inserted into opposite ends of the splice joint 4. When the opposing ends of the rigid rails 2 are butted together the threaded bolts 14 are tightened thereby gripping the rigid rail sections and securing the rigid rail sections in the splice joint 4. The trolley member will then be free to run in the channel 11 of the rigid rail 2 in an uninterrupted fashion.

Referring now to Fig.’s 10 and 11 of the drawings there are shown views of an intermediate support bracket 15. The intermediate support bracket 15 comprises a gripping portion 16 and a securing portion 17. The gripping portion further comprises a substantially u-shaped body portion 18 terminating at its ends in inwardly directed flanges 19. The internal dimensions of the intermediate support bracket 15 are such to receive the rigid rail relatively tightly therein. The gripping portion 16 is connected to the securing portion 17 by way of a bolt 20. The securing portion further comprises an L-shaped bracket, one leg of which is for connection to the gripping portion 16 by way of the bolt 20 and the other leg is for connection to a counterweight 3. In use, a length of'rigid rail 2 is sleeved by the gripping portion 16 of the intermediate bracket portion 15. The securing portion is then connected to a counterweight 3 thereby securing the rigid rail in position relative the elevated structure. The bolt 20 is tightened thereby preventing the intermediate support bracket from sliding along the rail. Sliding is also prevented by the counterweight 3.

Referring now to Fig.’s 12 and 13 there are shown different views of an end stop 21 in accordance with the invention. The end stop comprises a stop portion 22 connected to a mounting portion 23 by way of bolts 24. In use, an end stop 21 is secured adjacent a free end of the rigid safety rail thereby blocking the channel and preventing the trolley 5 from escaping from the channel 11.

Referring now to Fig.’s 14 and 15 there is shown a wall bracket support 25. The wall bracket support comprises a base 26 and a receiver socket 27 connected to the base - 9 IF <>307 04 portion 26. The socket 27 comprises a substantially u-shaped body portion 28 with each leg of the substantially u-shaped body portion terminating in an inwardly directed flange 29. The internal dimensions of the receiver portion 27 are such so as to receive the rigid rail 2 snugly therein. Fasteners, provided by bolts 30 are used to secure a rail 2 therein. In use, the base portion is secured by way of screws (not shown) or other suitable fasteners to a wall (not shown). One end of a length of rigid rail 2 is introduced into the socket 27. The bolts 30 are then tightened thereby gripping the rigid safety rail 2 and securing it in position.

Referring now to Fig.’s 16 and 17 of the drawings there is shown a permanent or one piece trolley, again indicated generally by the reference numeral 5. The trolley 5 comprises a body 32 mounting four wheels 33. The body 32 extends upwardly from the wheels 33 and separates into an enlarged bifurcated section 34 connected by a cross bar 35. In use, the trolley 5 is inserted into the channel 11 of the rigid rail 2 prior to both of the ends of the rigid safety rail 2 being sealed by way of an end stop 21 or wall bracket support 25. Once inserted into the channel 11 of the rigid rail 2, the trolley 5 is retained therein, the width of the body and wheels 31 combined being greater than the distance between the inwardly directed flanges 10 of the rigid safety rail 2. The safety line 7 is connected to the cross bar 35. The trolley 5 is free to roll within the channel 11 and thereby the employee wearing a safety harness 6 connected to the permanent trolley 5 by way of a safety line 7, is free to move along the perimeter of the structure whilst being prevented from accidentally falling over the edge of the structure. It will be understood that to prevent the employee from falling over the edge of the structure, the safety line must be shorter than the distance from the rail to the edge of the structure. Even if, in certain circumstances, due to the nature of the work being carried out, the worker were to fall over the edge of the building, the worker should not fall so far as not to be able to climb back onto the roof.

Referring now to Fig.’s 18 to 20 inclusive, there is shown a releasable trolley member indicated generally by the reference numeral 36, having a two part body portion 37a and 37b, each body portion having wheels 33 connected thereto. The body portions 37a and 37b are secured together by spring loaded U-shaped clamp 38. Each of the body portions 37a and 37b have a shackle receiving hole 39a and 39b respectively, formed therein for reception of a shackle 40 when the two body portions have been IE 03 07 84 - 10 joined together and with the spring loaded clamp 38 maintaining the body portions in a fixed relationship with respect to each other. A safety line 7 may then be secured to the shackle 40.

In order to insert the trolley 36 into the rigid rails channel 11, the shackle 40 is removed from the shackle receiving holes 39a and 39b. The spring loaded clamp 38 is removed and the two body portions 37a and 37b are separated from each other. Each body portion 37a, 37b is then inserted into the channel 11 of the rigid rail 2 with the wheels connected to each of the body portions 37a and 37b facing in opposite directions with respect to each other. The two body portions 37a and 37b are then brought together in the channel and the spring loaded clamp 38 is put in position thereby clamping the two body portions 37a and 37b together in a fixed relationship with respect to each other. Finally, the shackle 40 is inserted into the shackle receiving holes 39a and 39b thereby further securing the two body portions together. The individual width of a body portion 37a or 37b combined with the wheels 33 connected thereto is sufficiently narrow to allow insertion of the body portion and wheel into the channel 11 between the inwardly depending flanges 10 of the rigid safety rail 2. Once the trolley members body portions 37a and 37b have been connected together their combined width added to the width of the wheels 33 connected thereto is too wide to permit extraction of the trolley member from the rigid rails channel 11 between the inwardly directed flanges 10.

In order to release the trolley from the rigid rails channel 11, one simply undoes the shackle 40 and removes the shackle from the shackle receiving holes 39a and 39b, raises the spring loaded clamp 38 and separates the two body portions by sliding the body portions in opposite directions along the rigid rail. The body portions 37a and 37b will then be free to be removed from the channel 11. Once both body parts are free of the channel 11 they may be reassembled once again.

Referring now to Figs. 21 and 22 of the drawings there is shown an alternative embodiment of a releasable trolley, indicated generally by the reference numeral 45 in which parts similar to those described with reference to the previous drawing of the trolley 5 are identified by the same reference numerals. This trolley 45 is of substantially the same construction as the trolley 5, except that it does not use the UΙΕ η 3 07 04 shaped clamp 38. In this embodiment the body portions 37a and 37b are secured together by having a shackle (not shown) inserted through the shackle receiving holes 39a and 39b in the manner already previously described. The trolley 45 may be inserted into the channel or removed from the channel by removing the shackle from the shackle receiving holes 39a and 39b and thereafter separating the two body portions so that individually they may be inserted or removed from the channel.

While in the embodiments described above, the safety rail has been described as a continuous rail, it may be discontinuous to allow replacement or removal of a trolley.

Indeed, the rail may also be provided with removable portions which could provide locators for removal and/or replacement of a trolley.

In the embodiments shown the corner section 2b is curved in such a way that its ends are roughly orthogonal to each other. Of course, it must be understood that the corner sections could in fact be angled at greater or lesser angles depending on the individual requirements of the installation.

In this specification the term fall arrest system has been used throughout for convenience. It will be understood however that this is interchangeable with the term 0 fall restraint system and would be deemed obvious by the person skilled in the art that the terms were indeed interchangeable.

In this specification the terms comprise, comprises, comprised and comprising as well as the terms include, includes, included and including are all deemed to be totally interchangeable and should be afforded the widest possible interpretation.

The invention is in no way limited to the embodiments shown but can be varied in both construction and detail within the scope of the claims.

Claims (5)

1. A fall arrest system for mounting on the roof of a structure comprising a rigid safety rail comprising a track which is of a re-entrant channel shape having a slot of dimensions less than that of the trolley, mounting a wheeled trolley for securing to a safety harness and associated safety lines and a plurality of anchoring counterweights for securing to the rail and for positioning and resting on the roof, each counterweight having a roof engaging base, the roof engaging base being covered in a non-slip gripping layer.

2. A fall arrest system as claimed in any preceding claim, in which the trolley comprises a two part-body releasably secured together so that on separation the trolley may be removed from the track.

3. A fall arrest system as claimed in any preceding claim in which the rail comprises a box-like member comprising a base, mounting facing upstanding side walls, each terminating in an inwardly directed flange, the flanges forming an elongate re-entrant slot for reception of portion of the trolley therebetween, the interior of the base on both sides of the slot forming facing and spacedapart trolley wheel engaging tracks and in which the trolley comprise a twopart body releasably connected together, one part carrying a trolley wheel for engaging one track and the other part carrying a trolley wheel for engaging the other track, the dimensions of the body and wheels being such as to retain the trolley within the rail when connected together and on disengagement, to allow withdrawal through the slot.

4. A fall arrest system as claimed in any preceding claim in which the rigid rail comprises a plurality of rigid rail sections, each rigid rail section connected to another rigid rail section by way of a splice joint.

5. A fail arrest system substantially as described herein with reference to and as illustrated in the accompanying drawings.