EP2715012A1

EP2715012A1 - A fall arrest system

Info

Publication number: EP2715012A1
Application number: EP12726638.5A
Authority: EP
Inventors: Keith Turney; Stephen HOWGILL
Original assignee: Central (High Rise) Ltd
Current assignee: Central (High Rise) Ltd
Priority date: 2011-05-31
Filing date: 2012-05-29
Publication date: 2014-04-09
Also published as: WO2012164278A1; GB201109062D0; GB2491809A

Abstract

A safety clamp for use in a fall arrest system having first and second safety rail sections that meet at a junction is disclosed. The safety clamp comprises first and second passages configured to respectively receive the first and second safety rail sections to enable the safety clamp to slide along the safety rail sections and for the safety clamp to switch between receiving the first safety rail section and the second safety rail section as the clamp slides through the junction.

Description

A fall arrest system Description

The present invention relates to a fall arrest system for use in horizontal, inclined and vertical rail-based solutions for protecting workmen operating at elevated positions. The present invention also relates to a safety clamp for use in such a fall arrest system.

Workmen who need to gain access to elevated areas local to potential fall hazards are generally required by health and safety regulations to be equipped with an appropriate safety system such as a fall restraint or fall arrest system so that in the event of a slip or fall potential injury or fatality can be prevented. These systems typically involve the workman wearing a harness attached via a lanyard and a safety clamp to a safety rail mounted horizontally, vertically or at an angle to a building. In a fall arrest system where the safety rail comprises a vertical and/or inclined section in combination with a horizontal section, two differently configured safety clamps are required.

Known safety clamps configured to be used for a vertical or inclined section is provided with a braking mechanism. The braking mechanism typically engages with the safety rail in a resting state and so prevents the safety clamp from sliding downwards along the safety rail. If a workman were to slip the safety clamp would arrest the fall as the weight of the workman would cause the braking mechanism to further engage with the safety rail. When the workman moves in an upward direction the braking mechanism is released by the lanyard attached to the workman pulling on said braking mechanism, and so the clamp slides upwards along the safety rail as the workman moves in an upward direction.

Known safety clamp configured to be used in a horizontal section of a safety rail does not comprise a braking mechanism as this would prevent the workman from moving relatively unrestrained along the horizontal section. That is because the braking mechanism is not sufficiently released in response to the lanyard attached to the workman pulling on the braking mechanism as the workman moves in a horizontal direction. Furthermore, a braking mechanism in a clamp used for horizontal safety rails would restrict the workman to only be able to move in a unilateral direction and so the workman would not be able to return back along the horizontal safety rail section.

As a differently configured safety clamp is needed for a horizontal safety rail section compared to a vertical or inclined safety rail section, a workman needs to detach himself from one clamp and attach himself to another clamp when moving between a horizontal and a vertical/inclined section. This may be inconvenient for a workman as he cannot move freely between a horizontal and a vertical section and the step of changing clamps can leave the workman unprotected if they were to switch the connection of their lanyard to the clamps incorrectly.

The present invention seeks to provide a fall arrest system and a safety clamp for use in such a fall arrest system that overcome or substantially alleviate the problems mentioned above.

According to the present invention, there is provided a safety clamp for use in a fall arrest system having first and second safety rail sections that meet at a junction, the safety clamp comprising first and second passages configured to respectively receive the first and second safety rail sections to enable the safety clamp to slide along the safety rail sections and for the safety clamp to switch between receiving the first safety rail section and the second safety rail section as the clamp slides through the junction. Preferably, the safety clamp comprises an actuating member which is moveably mounted thereto and which includes a locking portion which is extendable into the second passage such that when safety clamp is in use with the second safety rail section received in the second passage, the actuating member can be moved towards an engaged position in which the locking portion engages the second safety rail section to prevent movement of the safety clamp relative to the second safety rail section. In one embodiment, only the second passage is provided with a locking portion of an actuating member so as to enable the safety clamp to slide freely in either direction along the first safety rail section when the first safety rail section is received in the first passage.

Conveniently, the actuating member can be moved towards a disengaged position in which the locking portion disengages the second safety rail section within the second passage so that the safety clamp can slide relative to the second safety rail section when in use.

Preferably, the actuating member is pivotally mounted to the safety clamp such that the actuating member is rotatable in one direction towards its engaged position and in an opposite direction towards its disengaged position.

Advantageously, the actuating member may be formed with an aperture on an opposite end to the locking portion for attachment of a lanyard connected to a user.

The safety clamp may comprise biasing means which bias the actuating member towards an engaged position.

Conveniently, the second passage is configured so as that it can receive a curved portion of the safety rail sections.

Preferably, the safety clamp further comprises a clamp bracket and a body, the actuating member being located between the clamp bracket and the body.

In one embodiment, the first and second passages are each defined by a wall which at least partially surrounds respective first and second passages.

Preferably, the first and second passages each comprises a longitudinal axis, the wall of each passage is formed with a gap that is parallel to said longitudinal axes.

Conveniently, the width of the gaps in a direction transverse to the longitudinal axes is smaller than the diameter of the safety rail sections to be received in the first and second passages which the safety clamp slides along when in use. The first and second passages may each comprise a longitudinal axis, the first and second passages may be spaced apart by a distance in a direction transverse to the longitudinal axes.

Preferably, the longitudinal axes of the first and second passages are non-coaxial.

Conveniently, the longitudinal axes of the first and second passages are parallel.

According to a second aspect of the invention, there is provided a fall arrest system comprising first and second safety rail sections that meet at a junction and a safety clamp comprising any of the aforementioned features, wherein the junction is configured so as to enable the safety clamp to switch between receiving the first safety rail section in the first passage and the second safety rail section in the second passage as the safety clamp slides through the junction.

The junction may comprise a support post and the safety rail sections each comprises a terminal end formed with a longitudinal axis, said terminal ends are attached to the post such that a space is formed therebetween in a direction transverse to the longitudinal axes so that the safety clamp can slide through the junction.

Preferably, the longitudinal axes of the terminal ends are non-coaxial.

Conveniently, the longitudinal axes of the terminal ends are parallel.

In one embodiment, the terminal ends are configured to correspond to the arrangement of the first and second passages of the safety clamp.

Advantageously, the terminal ends may be disposed adjacent one another such that as the safety clamp slides from the first safety rail section through the junction to the second safety rail section, the terminal end of the second safety rail section enters the second passage before the terminal end of the first safety rail section exits the first passage. In one embodiment, the fall arrest system further comprises a third safety rail section, wherein the second and the third safety rail section meet at a junction which comprises a turntable which enables the orientation of the safety clamp to be changed.

The gaps of each passage formed on the safety clamps may have a width in a direction transverse to their longitudinal axes that is smaller than the diameter of each of the first and second safety rail section. Preferably, the first safety rail section is substantially horizontal and the second safety rail section is substantially vertical.

Embodiments of the present invention will now be described by way of example only, with reference to the accompanying drawings, in which;

Figure 1 shows a fall arrest system according to the present invention;

Figure 2 shows an anchor holding an end of a horizontal and a vertical safety rail section which form part of the fall arrest system shown in Figure 1 ;

Figure 3 shows a perspective view of a safety clamp for use in the fall arrest system shown in Figure 1 ; and

Figure 4 shows an exploded view of the safety clamp illustrated in Figure 3.

Referring now to Figure 1, a fall arrest system 1 is shown comprising a safety clamp 2, a safety rail 3 formed of substantially horizontal and substantially vertical sections 4, 5 and an anchor 6 holding two ends 7, 8 of the two safety rail sections 4, 5. The safety clamp 2 is configured to be used for both the vertical and horizontal sections 4, 5 of the safety rail 3 by use of the anchor 6, as will become apparent from the description below. Figure 1 illustrates the safety rail 3 comprising the horizontal and the vertical sections 4, 5, however it should be understood that the term "vertical" used herein in association with a section of the safety rail 3 is to include any section that is inclined at any angle relative to a horizontal position. Furthermore, in Figure 1 the safety clamp 2 is shown in various locations along the safety rail 3 indicating that the safety clamp 2 is configured to slide along the whole safety rail. Similarly in Figure 2, the same safety clamp 2 is shown in two locations; the clamp 2 is located on the vertical safety rail section 5 to the left of the anchor 6 and on the horizontal safety rail section 4 to the right of the anchor 6.

The horizontal and the vertical safety rail sections 4, 5 are configured to be secured to a structure (not shown) such that the horizontal safety rail section extends along a horizontal part of the structure, for example a roof, and the vertical safety rail section extends along a vertical or inclined part of the structure, for example a wall. Each safety rail section comprises a first and a second end each having a

longitudinal axis. The first 7, 8 ends of the horizontal and vertical safety rail sections 4, 5 meet at a junction. The junction comprises an anchor 6 to which the first ends 7, 8 are attached as is best seen in Figure 2. The vertical safety rail section 5 bends towards a horizontal position as it approaches the anchor 6 such that the longitudinal axis of each first end 7, 8 are held parallel to one another and overlap for a small distance. The ends 7, 8 are also spaced apart in a direction transverse to the longitudinal axis so as to provide a space for the safety clamp 2 to slide through the anchor 6 as will become apparent from the description below.

The opposite second ends of each horizontal and vertical rail section 4, 5 are secured by appropriate means, such as an anchor known from the prior art or turn table 45, to the structure which the user wishes to climb. The anchor 6 holding the two first ends 7, 8 comprises a post 9 formed with a base 10 provided with two holes 11 so that the anchor 6 can be secured to a structure (not shown) to which the safety rail 3 is to be attached. On an opposite end of the post 9, the anchor 6 is provided with two plates 12, 13. The first plate 12 comprises a first section 15 formed with a hole (not shown) enabling the plate 12 to be attached to the post 9 using a bolt 17. A second section 16 of the first plate 12 is bent such that the over all first plate 12 folds back on itself. The second plate 13 is also formed with a hole (not shown) which is aligned with the hole of the first plate 12, such that the bolt 17 extends through both holes and secures both plates 12, 13 to the post 9 of the anchor 6. The second plate 13 is positioned on top of the first plate 12 such that its plane is parallel to the plane of the first section 15 of the first plate 12. The second plate 13 also extends for a distance over the second bent section 16 of the first plate 13 such that the two plates 12, 13 together form a bracket having a partial rectangular cross-section. In the upper part of the bracket an opening is formed which is defined by an edge 14a of the first plate 12 and an edge 14b of the second plate 13. The first ends 7, 8 of the horizontal and vertical safety rail sections 4, 5 are attached to either edge 14a, 14b of the opening of the bracket such that the longitudinal axes of the ends 7, 8 are parallel with said edges 14a, 14b.

The anchor 6 provides a junction where the first ends 7, 8 of the horizontal and vertical safety rail sections 4, 5 meet such that they form a continuous safety rail 3. The space formed between the ends 7, 8 of the horizontal and vertical section 4, 5 in a direction transverse to the longitudinal axis of the ends enable the safety clamp 2 to slide through the anchor 6. As the safety clamp 2 slides through the anchor the clamp switches between sliding on the vertical section 5 to the horizontal section 4 and vice versa. The safety clamp 2 shown in figures 1 to 4, comprises a body 20 having an upper portion 21 and a first and a second hook portion 22, 23 which extend in opposite directions from an end of the upper portion 21. The upper portion 21 extends over the first hook portion 21 so as to define a passage 24 for receiving the horizontal safety rail section 4. An edge 26 of the upper portion 21 is parallel and spaced from an edge 27 of the first hook portion 22 so as to form a gap to enable the second section 16 of the first plate 12 of the anchor 6 attached to the horizontal safety rail section to pass through as the safety clamp 2 slides through the anchor 6.

The second hook portion 23 together with a clamp bracket 31 form a passage 25 for receiving a vertical section 5 of the safety rail 3. The clamp bracket 31 is formed with a wall 32 having two side walls 33, 34 that extend on either side of the upper portion 21 of the body 20 of the safety clamp 2. Lower edges of the side walls 33, 34 are formed with two recesses 35, 36 so as to accommodate for the vertical and the horizontal safety rail sections 4, 5. Furthermore, the side walls 33, 34 are each formed with a hole 37 that correspond to a path 38 formed in the upper portion 21 of the body 20 of the safety clamp 2. The holes 37 of the clamp bracket 31 and the path 38 of the body 20 are aligned and a hinge pin 39 is received in the holes 37 and the path 38 such that the clamp bracket 31 is secured to the body 20. To prevent the clamp bracket 31 from rotating about a longitudinal axis of the hinge pin 39 relative to the body 21, a hole 50 is formed in the body 20 that extend from an upper surface of the upper portion 21 towards the path 38 formed in the body 20 of said safety clamp 2 such that the hole 50 is perpendicular to said path 38. A screw or a plug 51 is inserted in the hole 50 which engages the hinge pin 39 such that any pivotal movement of the clamp bracket 31 relative to the body 20 of the safety clamp 2 is restricted.

The safety clamp 2 further comprises a lever 28 also referred to as an actuating member which locates in the second passage 25 configured to receive the vertical safety rail section 5. The actuating member 28 is formed with an aperture 29 at one end for receiving a carabiner (not shown) which is connected to a user's harness via a lanyard, and a stopping portion 30 at the opposite end which engages the vertical safety rail section 5.

The actuating member 28 is pivotably attached to the clamp bracket 31 by the use of a pin 40 having a threaded end. The pin 40 is inserted through a hole 41 formed in the actuating member 28 and the threaded end of the pin 40 is received and secured to a threaded pin receiving hole 42 formed in the clamp bracket 31. The actuating member 28 is biased by a spring 43 towards a resting position in which the stopping portion 30 engages the vertical safety rail section 5 thereby preventing the safety clamp 2 from moving in a downward direction along the vertical safety rail section 5. In response to a downward load applied to the actuating member 28 such as the weight of a user, the actuating member 28 rotates relative to the body 2 and the clamp bracket 31 towards a fall arrest position in which the stopping portion 30 further engages the vertical safety rail section 5 thereby preventing any downward movement of the safety clamp 2 along the vertical safety rail section 5. Therefore, a fall of a user along a vertical safety rail section will be arrested. As a user moves in an upward direction along the vertical safety rail section 5, the actuating member 28 moves towards a disengaged position in that it is released from the resting position by the lanyard attached to the safety clamp 2 pulling on the actuating member 28 such that it rotates in an opposite direction to when a downward load is applied. The actuating member 28 can be rotated relative to the clamp bracket 31 towards a disengaged position to such an extent that stopping portion 30 is withdrawn from the second passage 25. Furthermore, the second passage 25 is configured to provide sufficient space around the vertical safety rail section so as to enable the safety clamp to pass the bent section of the vertical safety rail section adjacent to the anchor 6.

If a workman wants to move in a downward direction along the vertical section 5, they would have to rotate the actuating member 28 manually towards a disengaged position. The safety clamp 2 can be slid down a vertical section 5 as long as the workman holds the actuating member 28 in the disengaged position. If the workman was to lose his grip of the actuating member 28 and the safety clamp 2, the spring 43 would push the actuating member 28 towards a resting position in which the safety clamp 2 engages the safety rail. Furthermore, if the workman was to fall the spring 43 would push the actuating member 28 towards the resting position and the weight of the workman pulling on the actuating member would further rotate the actuating member 28 towards a fall arrest position in which the stopping portion 30 fully engages the vertical safety rail section 5 thereby preventing any downward movement of the safety clamp 2 along the vertical safety rail section 5.

Operation of the fall arrest system will now be described with reference to Figures 1 to 4. The safety clamp 2 is described to move from a vertical section to a horizontal section of the safety rail however it should be understood that the safety clamp 2 can be moved from the horizontal section to the vertical section of the safety rail.

The safety clamp 2 is located on the vertical section 5 of the safety rail 3 by the second passage 25 of the safety clamp 2 receiving said vertical safety rail section 5. A user attaches their harness (not shown) via a lanyard (not shown) to the aperture 29 of the actuating member 28 of the safety clamp 2. The user is now protected in an event of a fall as the actuating member 28 prevents the safety clamp 2 from sliding downwards along the vertical safety rail section 5 as described above. The user then moves in an upward direction so as to reach desired elevated heights. When the user reaches the junction of the vertical and the horizontal safety rail sections 4, 5, the safety clamp 2 is pulled through the anchor 6 by the lanyard pulling on the actuating member 28. As the safety clamp 2 enters the bracket of the anchor 6, the end 7 of the horizontal safety rail section 4 enters the first passage 24 such that the end of both the horizontal and vertical safety rail sections 4, 5 simultaneously are located in their respective first and second passages 24, 25 of the safety clamp 2. The safety clamp 2 receives both the horizontal and the vertical safety rail sections 4, 5 simultaneously until the safety clamp 2 exits the anchor 6 by which point the end 8 of the vertical safety section 5 is withdrawn from the second passage 25 of the safety clamp 2. The user is now attached to the horizontal section 4 of the safety rail 3 by the horizontal safety rail section 4 being received in the first passage 24 of the safety clamp 2. As the first passage 24 of the safety clamp 1 is not provided with an actuating member, the user can move bilaterally relatively freely along the horizontal safety rail section 4. Furthermore, as there is no safety rail section in the second passage 25 of the safety clamp 2, the actuating member 28 does not engage with a safety rail section 3 and so does not impede on the movement of the safety clamp 2, and thus the user's movement, in a horizontal direction. If the user was to fall when attached to the horizontal safety rail section 4, the safety clamp 2 would arrest the fall as it is prevented to move in a vertical direction by the horizontal safety rail section 4.

It should be appreciated that the safety clamp 2 can be pulled in the opposite direction through the anchor 6 such that the safety clamp 2 is switched from being secured to the horizontal section 4 to being secured to the vertical section 5. When doing so, the workman would have to assist the safety clamp by pulling on the actuating member towards a disengaged position as the first end 8 of the vertical safety rail section 5 enters the second passage 25. The workman would have to continue holding the actuating member in a disengaged position if the workman would continue moving down the vertical safety rail section 5. Although, the two first ends 7, 8 of the horizontal and vertical sections 4, 5 have been described to overlap, it should be understood that they can be spaced apart by a distance in a direction along the longitudinal axes of the first ends. However, this distance is limited by the length of the safety clamp, because in order for the safety clamp to switch between the horizontal and vertical safety rail sections both outermost ends of each first ends 7, 8 must simultaneously be located within their respective passages of the clamp as the clamp 2 slides through the anchor 6. The fall arrest system 1 according to the present invention overcomes the problem of having to use a different safety clamp for a vertical safety rail section and a horizontal safety rail section. In the present invention, the same safety clamp 2 is used for both the horizontally and the vertical sections 4, 5 of the safety rail 3. This is achieved by the actuating member 28 functioning as an attachment site for the harness of the user as well as a lever so as to arrest a fall along a vertical section of the fall arrest system. The actuating member 28 also functions as an attachment site for the harness of a user in a horizontal section 4 of the safety rail and

advantageously, when the safety clamp 2 is located on a horizontal safety rail section 4 the actuating member 28 never engages with a safety rail section in either a resting state or when the lanyard pulls on the actuating member 28 in response to the user moving horizontally along the horizontal safety rail section 4 and so a user can move freely in either direction along the horizontal safety rail section 4.

Advantageously, the fall arrest system according to the present invention enables a user to move relatively freely to elevated heights along horizontal and vertical structures as there is no need for the user to re-attach themselves to a different clamp as they move between horizontal and vertical safety rail sections.

It is envisaged that the fall arrest system 1 according to the present invention can include multiple horizontal and vertical safety rail sections. For example, the fall arrest system may comprise a horizontal safety rail section having first and second vertical safety rail sections extending downwards from either end of the horizontal safety rail section such that the overall safety rail forms an upside down u-shape. A workman moving along the entire u-shaped safety rail would initially move upwards along the first vertical safety rail section, then move along the horizontal safety rail section, and finally move in a downward direction along the second vertical safety rail section. In this case, the safety clamp 2 is initially positioned on the first vertical safety rail section with a first end uppermost and as the safety clamp slides onto the second vertical safety rail section via the horizontal section, the first end becomes lowermost such that the safety clamp 2 is upside down. To avoid the safety clamp being positioned upside down a turntable can be used which comprises a rotatable platform formed with a portion of a safety rail. Preferably, the turntable is located on the horizontal safety rail section such that it is in between two parts of the horizontal safety rail section. To change orientation of the safety clamp, the turntable is rotated so that the safety rail portion of the turntable is aligned with the two parts of the horizontal safety rail section. Thereafter, the safety clamp is slid onto the portion of the safety rail and the turntable is rotated by 180°. The clamp can then be slid back onto either parts of the horizontal safety rail section with the first end facing the opposite direction. Therefore, the orientation of the safety clamp can be changed if required prior to the safety clamp sliding onto a vertical section so that the safety clamp slides on the vertical safety rail with the first end facing upwards.

It should be appreciated that the turntable can alternatively be positioned along the vertical safety rail section, in particular, the turntable can be positioned either before or after the bent section of the vertical safety rail section. The fall arrest system 1 according to the present invention may also comprise two horizontal sections each comprising a first end that meet at a junction. The horizontal sections may meet at an angle to each other, for example the horizontal sections may meet at 90° to each other as illustrated in Figure 1. To enable the safety clamp 2 to slide from one horizontal safety rail section to the other the junction comprises a turntable 45 as the one described above. To slide the safety clamp 2 from one horizontal section to another, the turntable 45 is rotated so that the safety rail portion of the turntable is aligned with the horizontal safety rail section on which the safety clamp is located. Thereafter, the safety clamp 2 is slid onto the safety rail portion and then the turntable is rotated 90° so that the safety rail portion of the turntable is aligned with the other horizontal safety rail section enabling the safety clamp 2 to slide onto said other horizontal safety rail section. Alternatively, the safety rail section according to the present invention may comprise two horizontal sections each comprising a first end that meet at a junction, wherein the horizontal sections are attached to the anchor 6 as described with reference to Figures 1 to 4. This may for example be the case wherein a safety rail is required to extend for a length greater than a single horizontal safety rail section such that a plurality of horizontal safety rail sections are needed. In this embodiment, the safety clamp is configured as described with reference to Figures 1 to 4 however without the actuating member 28 extending into the second passage 25 receiving the vertical safety rail section. That is to avoid the actuating member 28 interfering with the horizontal safety rail sections and thus the safety clamp's ability to slide along the horizontal safety rail sections. In this embodiment, the body of the safety clamp may be formed with an aperture for receiving the lanyard attached to a workman's harness.

Although embodiments of the invention have been shown and described, it will be appreciated by those skilled in the art that variations may be made to the above exemplary embodiments that lie within the scope of the invention, as defined in the following claims.

Claims

1. A safety clamp for use in a fall arrest system having first and second safety rail sections that meet at a junction, the safety clamp comprising first and second passages configured to respectively receive the first and second safety rail sections to enable the safety clamp to slide along the safety rail sections and for the safety clamp to switch between receiving the first safety rail section and the second safety rail section as the clamp slides through the junction.

2. A safety clamp according to claim 1, comprising an actuating member which is moveably mounted thereto and which includes a locking portion which is extendable into the second passage such that when safety clamp is in use with the second safety rail section received in the second passage, the actuating member can be moved towards an engaged position in which the locking portion engages the second safety rail section to prevent movement of the safety clamp relative to the second safety rail section.

3. A safety clamp according to claim 2, wherein only the second passage is provided with a locking portion of an actuating member so as to enable the safety clamp to slide freely in either direction along the first safety rail section when the first safety rail section is received in the first passage.

4. A safety clamp according to either of claim 2 or claim 3, wherein the actuating member can be moved towards a disengaged position in which the locking portion disengages the second safety rail section within the second passage so that the safety clamp can slide relative to the second safety rail section when in use.

5. A safety clamp according to claim 4, wherein the actuating member is pivotally mounted to the safety clamp such that the actuating member is rotatable in one direction towards its engaged position and in an opposite direction towards its disengaged position.

6. A safety clamp according to any of claims 2 to 5, wherein the actuating member is formed with an aperture on an opposite end to the locking portion for attachment of a lanyard connected to a user.

7. A safety clamp according to any of claims 2 to 6, further comprising biasing means which bias the actuating member towards an engaged position.

8. A safety clamp according to any of claims 2 to 7, wherein the second passage is configured so as that it can receive a curved portion of the safety rail sections.

9. A safety clamp according to claim 8, wherein the safety clamp further comprises a clamp bracket and a body, the actuating member being located between the clamp bracket and the body.

10. A safety clamp according to any preceding claim, wherein the first and second passages are each defined by a wall which at least partially surrounds respective first and second passages.

11. A safety clamp according to claim 10, wherein the first and second passages each comprises a longitudinal axis, the wall of each passage is formed with a gap that is parallel to said longitudinal axes.

12. A safety clamp according to claim 11, wherein the width of the gaps in a direction transverse to the longitudinal axes is smaller than the diameter of the safety rail sections to be received in the first and second passages which the safety clamp slides along when in use.

13. A safety clamp according to any preceding claim, wherein the first and second passages each comprise a longitudinal axis, the first and second passages are spaced apart by a distance in a direction transverse to the longitudinal axes.

14. A safety clamp according to claim 13, wherein the longitudinal axes of the first and second passages are non-coaxial.

15. A safety clamp according to claim 13 or claim 14, wherein the longitudinal axes of the first and second passages are parallel.

16. A fall arrest system comprising first and second safety rail sections that meet at a junction and a safety clamp according to any of claims 1 to 15, wherein the junction is configured so as to enable the safety clamp to switch between receiving the first safety rail section in the first passage and the second safety rail section in the second passage as the safety clamp slides through the junction.

17. A fall arrest system according to claim 16, wherein the junction comprises a support post and the safety rail sections each comprises a terminal end formed with a longitudinal axis, said terminal ends are attached to the post such that a space is formed therebetween in a direction transverse to the longitudinal axes so that the safety clamp can slide through the junction.

18. A fall arrest system according to claim 17, wherein the longitudinal axes of the terminal ends are non-coaxial.

19. A fall arrest system according to claim 17 or claim 18, wherein the longitudinal axes of the terminal ends are parallel.

20. A fall arrest system according to any of claims 17 to 19, wherein the terminal ends are configured to correspond to the arrangement of the first and second passages of the safety clamp.

21. A fall arrest system according to any of claims 17 to 20, wherein the terminal ends are disposed adjacent one another such that as the safety clamp slides from the first safety rail section through the junction to the second safety rail section, the terminal end of the second safety rail section enters the second passage before the terminal end of the first safety rail section exits the first passage.

22. A fall arrest system according to any of claims 16 to 21, wherein the fall arrest system further comprises a third safety rail section, wherein the second and the third safety rail section meet at a junction which comprises a turntable which enables the orientation of the safety clamp to be changed.

23. A fall arrest system according to any of claims 16 to 22 when dependent on claim 10, wherein the width of the gaps of the passages in a direction transverse to their longitudinal axes is smaller than the diameter of each of the first and the second safety rail section.

24. A fall arrest system according to any of claims 16 to 23, wherein the first safety rail section is substantially horizontal and the second safety rail section is substantially vertical.