GB2514155A

GB2514155A - Fall arrest traveller

Info

Publication number: GB2514155A
Application number: GB1308758.0A
Authority: GB
Inventors: John P Slaven
Original assignee: Spanset Inter AG
Current assignee: Spanset Inter AG
Priority date: 2013-05-15
Filing date: 2013-05-15
Publication date: 2014-11-19
Also published as: GB201308758D0

Abstract

A fall arrest traveller 1 comprises a housing, which defines a passageway for the safety line 100 and an actuation member 4 with arm 43, which is coupled to an engagement member 5 via a coupling member 6. On falling, the traveller 1 falls downwardly along the safety line 100. Due to the contact of the engagement member 5 with the safety line, friction between the safety line causes the engagement member 5 to move vertically upwards from a second position until it reaches a third position, in which protrusions 77 reach the ends 62 of the second slots 52 (figs 3& 4). As the engagement member 5 moves from a second position to a third position, it translates relative to the actuation member 4, i.e. relative to the coupling member 6, and the arcuate protrusion 93 of the arm 43 and abuts surfaces 74, 75 on the engagement member 5 to increase the force of engagement of the engagement member 5 with the safety line 100.

Description

Fall Arrest Traveller The present invention relates to a fall arrest traveller and to a fall arrest system comprising a fall arrest traveller.

In many occupations it is necessary for a person to work in a dangerous environment, such as from a substantial height. In order to protect a person from falling in such an environment it is necessary, and often a legal requirement, to provide a substantially vertical safety line that is attached to the structure on which the person is working, which the person is attached to when working on the structure.

A fall arrest traveller is a safety device which attaches a person, or other load, to the safety line and travels along the safety line with the person, to allow the person to move around the structure they are working on, while remaining attached to the safety line. If a user falls, the traveller locks onto the safety line to arrest their fall.

A known fall arrest traveller comprises a housing defining a passageway for receiving a vertical safety line An arm is pivotally mounted on the housing, the arm having a first end which is provided with an aperture for attachment to a user's safety harness and a second end which is curved to form an engagement surface. When the user falls, the falling weight of the user actuates the first end of the arm downwards. This pivots the engagement surface of the second end of the arm against the safety line, which clamps the safety line within the passageway and so locks the traveller in position on the safety line.

However, this suffers from the disadvantage that, under certain conditions, the fall arrest traveller fails to lock quickly enough onto the safety line when a person falls.

Accordingly, the person can fall a dangerous distance before the traveller locks onto the safety line.

Specifically, the fall arrest traveller fails to lock quickly enough to the safety line because the locking of the traveller is dependent on the speed of fall of the person relative to the traveller. Accordingly, the traveller will only lock when a person has fallen past the traveller by a certain vertical distance, and at a certain relative speed, so that the engagement surface of the second end of the arm engages the safety line with sufficient force to lock the traveller on the safety line.

When a person falls from a structure, such as a ladder, they tend to first fall backwards in a substantially horizontal direction, before they fall vertically downwards. While the person falls horizontally, the traveller falls vertically along the safety line. Therefore, the person can fall a dangerous distance before they have fallen far enough past the traveller in the vertical direction, and with enough vertical speed relative to the traveller, for the traveller to lock onto the safety line. The extent of this problem increases with the lower the weight of the person.

It is an object of the present invention to overcome or mitigate the above problems. It is also an objection of the present invention to provide an alternative fall arrest traveller and an alternative fall arrest system.

According to a first aspect of the present invention there is provided a fall arrest traveller for slidable attachment to a safety line comprising a passageway for a safety line, an actuation member for connection to a person and an engagement member for selective engagement with a safety line received within said passageway, the actuation member is arranged such that it occupies a first position when a person connected to the actuation member is travelling upwardly or downwardly along the safety line and is coupled to the engagement member such that when the actuation member is in its first position, the engagement member occupies a first position in which it allows slidable movement of the fall arrest traveller upwardly or downwardly along the safety line and when the actuation member is in a second position the engagement member occupies a second position in which it contacts the safety line, wherein the engagement member is movable relative to the actuation member from its second position to a third position and is arranged such that slidable movement of the fall arrest traveller downwardly along the safety line causes the engagement member to move from its second position to its third position in which it engages the safety line so as to slow down or stop movement of the fall arrest traveller downwardly along the safety line.

Since, when it is in its second position, the engagement member contacts the safety line such that slidable movement of the fall arrest traveller downwardly along the safety line causes the engagement member to engage the safety line, the engagement of the engagement member with the safety line is dependent on the movement of the fall arrest traveller downwardly along the safety line. Accordingly, the engagement is not dependent on the speed or direction of fall of a person relative to the fall arrest traveller, but is dependent on the speed of fall of the fall arrest traveller along the safety line. This prevents a person from falling a dangerous distance before the fall arrest traveller locks onto the safety line.

In this respect, when the actuation member is in its second position, the engagement member is moved to its second position in which it automatically engages the safety line as soon as the fall arrest traveller moves downwardly along the safety line.

Accordingly the fall arrest traveller locks onto the safety line as soon as a person begins to fall.

Furthermore, since the engagement member is movable relative to the actuation member, from its second position to its third position, the engagement of the engagement member with the safety line is not dependent on how far the actuation member moves from its second position nor the force with which the actuation member moves. Therefore, the locking of the traveller on the safety line is not dependent of the speed or direction of fall of the person relative to the fall arrest traveller.

Preferably the actuation member is arranged such that it occupies its first position when a person connected to the actuation member is travelling upwardly and downwardly along the safety line.

Preferably when the engagement member is in its first position, it allows slidable movement of the fall arrest traveller upwardly and downwardly along the safety line.

Preferably when the engagement member is in its first position, it is spaced from the safety line such that it does not contact the safety line.

Preferably the actuation member is biased into its second position by a biasing member.

Preferably the weight of the fall arrest traveller and the biasing member are arranged such that as the person travels upwardly and/or downwardly along the safety line, the actuation member occupies its first position.

Preferably the actuation member comprises an arm for connection to a person and a coupling member which couples the arm to the engagement member.

Preferably the passageway for the safety line extends in a longitudinal direction.

Preferably the actuation member is arranged such that, when it is in its first position, its arm is inclined relative to an axis that is substantially perpendicular to said longitudinal direction. Preferably when the actuation member is in its first position, its arm is inclined between said longitudinal direction and an axis that is substantially perpendicular to said longitudinal direction.

Preferably the actuation member is arranged such that, when it is in its first position, its arm is inclined relative to the horizontal direction. Preferably when the actuation member is in its first position, its arm is inclined between the horizontal and vertical directions.

Preferably the actuation member is arranged such that when it is in its second position, its arm is substantially perpendicular to said longitudinal direction.

Preferably the actuation member is arranged such that when it is in its second position, its arm is substantially horizontal.

Preferably when the actuation member is in its first position, the arm and coupling member occupy a first position and when the actuation member is in its second position, the arm and coupling member occupy a second position.

Preferably the coupling member is biased into its second position by the biasing member. Preferably the biasing member is a resiliently deformable element, such as a spring.

Preferably the actuation member is movable from its second position to a third position in which it engages the engagement member so as to increase the force of engagement of the engagement member with the safety line.

This is advantageous in that, when a person is stationary on the safety line, or begins to fall, the actuation member is in its second position and the engagement member is in its second position. The upwards movement of the safety line relative to the fall arrest traveller (the safety line is stationary and the fall arrest traveller is falling downwardly along the safety line) causes the engagement member to move from its second position to its third position to engage the safety line so as to slow down or stop the upward movement of the safety line relative to the passageway (as described above). This causes the falling person to overtake the fall arrest traveller, which moves the actuation member to its third position. In its third position, the actuation member increases the force of engagement of the engagement member with the safety line.

Preferably the arm is movable relative to the coupling member from its second position to a third position such that when the actuation member occupies its second and third positions, the arm occupies its second and third positions. When the actuation member is in its third position, the coupling member may be in its second position.

Preferably one of the arm and the coupling member is provided with a first protrusion and the other of the arm and the coupling member is provided with a first slot, wherein the first protrusion is slidable within the first slot such that the arm is movable relative to the coupling member between its second and third positions.

Preferably when the arm is in its first position, the first protrusion engages the first slot such that the coupling member is moved to its first position.

Preferably when the arm is in its second position, the first protrusion engages the first slot such that the coupling member is moved to its second position.

Preferably one of the actuation member and the engagement member is provided with a second protrusion and the other of the actuation member and the engagement member is provided with a second slot and the second protrusion is slidable within the second slot such that the engagement member is movable relative to the actuation member between its second and third positions. Preferably one of the coupling member and the engagement member is provided with said second protrusion and the other of the coupling member and the engagement member is provided with said second slot Preferably the actuation member is rotatably mounted to a pivot member such that it is rotatable from its first position to its second position about an axis. Preferably the arm of the actuation member is rotatable from its second position to its third position about said axis.

Preferably the engagement member is arranged such that as the engagement member moves from its second position to its third position, the force exerted on the engagement member, when it engages the safety line, acts through said axis.

This is advantageous in that the force of engagement does not create a bending moment on the actuation member, about said axis. Preferably as the engagement member moves from its second position to its third position, it bears against the pivot member.

Preferably the safety line extends upwardly.

According to a second aspect of the invention there is provided a fall arrest system comprising an upwardly extending safety line attached to a structure, a harness for a person and a fall arrest traveller according to the first aspect of the invention, wherein the fall arrest traveller is slidably attached to the safety line and the harness is attached to the actuation member of the fall arrest traveller.

Preferably the safety line is substantially vertical.

All of the features described herein may be combined with any of the above aspects, in any combination.

A specific embodiment 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 front perspective view of a fall arrest traveller according to the invention; Figure 2 shows a front elevational view of the fall arrest traveller of figure 1, shown with the front of the fall arrest traveller omitted for illustrative purposes, with an actuation member of the fall arrest traveller shown in a first position and with the fall arrest traveller mounted on a safety line (shown in a dotted line); Figure 3 shows a view corresponding to that of figure 2 but with the actuation member shown in a second position; Figure 4 shows a view corresponding to that of figures 2 and 3, but with the actuation member in a third position, and Figure 5 shows a fall arrest system comprising the fall arrest traveller shown in Figures 1 to 4.

Referring to Figure 5, there is a shown a fall arrest system 300 comprising a substantially vertical safety line 100 fixed to a support structure 101. First and second ends 102, 103 of the safety line 100 are fixed to the support structure 101 by respective mounting brackets 104, 105. The fall arrest system 300 further comprises a fall arrest traveller 1 that is slidably mounted on the safety line 100. The fall arrest traveller 1 is for connection to a user, for example to a harness of a user either directly, or by a rope and/or karabiner (not shown).

Referring now to Figures 1 to 4, the fall arrest traveller 1 comprises a housing 2, which defines a passageway 3 for the safety line 100 and an actuation member 4, which is coupled to an engagement member 5.

The housing 2 comprises opposed first and second housing plates 31, 32 that are spaced apart in a lateral direction to define an enclosure. The second housing plate 32 is folded along one side to form a lip 33. An inner surface 34 of the lip 33 defines said passageway 3, which has a longitudinal axis 11.

The fall arrest traveller 1 is slidably attached to the safety line 100 by receiving the safety line 100 within the passageway 3. As the fall arrest traveller 1 slides along the safety line 100, the safety line 100 moves relative to the passageway 3, i.e. as the fall arrest traveller slides downwardly along the safety line 100, the safety line 100 moves relative to the fall arrest traveller in an upward direction (and vice versa).

The actuation member 4 comprises an elongate arm 43 and a coupling member 6.

The coupling member 6 is received within the enclosure defined by the first and second plates 31, 32 of the housing 2. The coupling member 6 comprises first and second plates 16, 17 which are spaced apart in the lateral direction and extend substantially parallel to each other. Each coupling plate 16, 17 extends in a direction that is generally parallel to an adjacent inner surface of the first and second plates 31, 32 of the housing 2 respectively. Each coupling plate 16, 17 extends between first and second side edges 21, 22, that are inclined relative to each other at an angle slightly greater than 90° and are bounded by an arcuate edge 23 (see Figure 4).

A pin 14 passes through a central section of the first and second plates 31, 32 of the housing 2 and is rotatably fixed at each of its ends to the first and second plates 31, 32 respectively. The pin 14 is generally elongate and extends along a longitudinal axis 50 (see Figure 1) that is substantially perpendicular to the first and second plates 31, 32 of the housing 2.

The pin 14 passes through first and second co-axial bores 41 provided in central sections of the first and second plates 16, 17 of the coupling member 6 respectively (only the first bore 41 is shown in the Figures). The first and second plates 16, 17 of the coupling member 6 are rotatably mounted to the pin 14, for rotation relative to the pin 14. A bearing element, in the form of a plain or journal bearing (not shown) is provided between the pin 14 and respective inner surfaces of the coupling plates 16, 17 that define said first and second bores 41.

Opposed inner surfaces of the first and second plates 16, 17 are connected to the pin 14 by a rotational spring (not shown).

The elongate arm 43 extends along a longitudinal axis, between first and second ends 12, 13 (see Figure 2). The arm 43 has first and second surfaces which each face an adjacent inner surface of the first and second plates 31, 32 of the housing 2 respectively The first and second surfaces are substantially flat and are bounded by upper and lower edges 91, 92 that extend in the direction of the longitudinal axis of the arm 43.

The pin 14 passes through a bore provided towards the second end 13 of the arm 43 that extends through the arm 43 from its first to its second surfaces. The arm 43 is rotatably mounted to the pin 14, for rotation relative to the pin 14. Accordingly, the coupling member 6 and the arm 43 are rotatable about the same axis 50. A bearing element, in the form of a plain or journal bearing (not shown) is provided between the pin 14 and respective inner surface of the arm 43 that defines the bore.

The arm 43 is disposed between the first and second plates 16, 17 of the coupling member 6 and rotates relative to the first and second plates 16, 17 of the coupling memberS as it rotates about the pin 14.

The first end 12 of the arm 43 is shaped to form a generally circular outer edge and is provided with an internal bore 15. The bore 15 is for connection to a user, for example to a harness of a user either directly, or by a rope and/or karabiner (not shown).

Each of the first and second surfaces of the arm 43 is provided with a first protrusion 24 (the protrusion on the second surface is not shown in the Figures) that is disposed approximately a third of the way along the length of the arm 43 from its second end 13 and generally mid-way between the upper and lower edges 91, 92 of the arm 43.

Each of the first protrusions 24 protrudes from the first or second surface of the arm 43 respectively. Each first protrusion 24 is generally cylindrical and extends along a longitudinal axis that is substantially perpendicular to the first or second surface of the arm 43 respectively. The longitudinal axes of the first protrusions 24 are substantially parallel and aligned with each other.

The lower edge 92 of the arm 43 is provided with an arcuate protrusion 93 that extends away from the lower edge 91 along an axis 95 that is substantially arcuate.

The axis 95 describes a section of a curve that is substantially concentric with the longitudinal axis 50 of the pin 14. The protrusion 93 is provided between the first and second plates 16, 17 of the coupling member 6. A radially outer surface of the protrusion 93 is substantially parallel to and aligned with the arcuate side edge 23 of the first and second plates 16, 17 of the coupling member 6.

The first and second plates 16, 17 of the coupling member 6 are each provided with a first slot 51, as shown in Figure 4 (only the first slot 51 of the first plate 16 is shown in the figures). The first slot 51 is generally arcuate and extends from a first end 54 that is proximal to the first side edge 21 of the respective plate 16, 17 to a second end 55 that is distal to the first side edge 21, about a generally arcuate axis 56. The arcuate axis 56 describes a section of a curve that is substantially concentric with the longitudinal axis 50 of the pin 14. The first slot 51 extends from a front face of the respective plate 16, 17, through the thickness of the plate, to a rear face of the plate 16, 17. The first slot 51 is provided towards the arcuate side edge 23 of the respective plate 16, 17 and the axis 56 of the first slot 51 is substantially parallel to the arcuate side edge 23 of the respective plate 16, 17. The first slots 51 of the first and second plates 16, 17 of the coupling member 6 are substantially aligned with each other and are laterally opposed to each other.

The first and second plates 16, 17 of the coupling member 6 are also each provided with a second slot 52 (only the second slot 52 of the first plate 16 is shown in the figures) that extends from a first end 61 that is generally proximal to the arcuate side edge 23 of the respective plate 16, 17 to a second end 62 that is generally distal to said arcuate edge 23. Each second slot 52 extends along a substantially straight axis 53. Each of the second slots 52 extends from the front face of the respective plate 16, 17, through the thickness of the plate, to the rear face of the plate 16, 17. The second slots 52 are substantially aligned with each other and are laterally opposed to each other.

Each first protrusion 24 of the first and second surfaces of the arm 43 is received within the first slot 51 of the first or second coupling plates 16, 17 respectively.

Opposed, longitudinally extending, sides of each slot 51 form a close fit with the respective protrusion 24 such that each slot 51 forms a guide for the respective protrusion 24. As the arm 43 rotates about the pin 14 (as discussed in more detail below), each first protrusion 24 translates within its respective slot 51, from the first end 54 to the second end 55 of the slot 51, and traces an arcuate path that is substantially parallel to the arcuate axis 56 of the slot 51.

The engagement member 5 comprises a substantially solid body that extends between a front surface 73 and a rear surface (not shown) along a longitudinal axis that is substantially parallel to the longitudinal axis 50 of the pin 14 (see Figure 3).

The engagement member 5 has a generally wedge shaped cross sectional shape, about its longitudinal axis.

A first side of the engagement member 5, that faces the inner surface 34 of the lip 33 has a first surface 71 that is substantially planar and extends from a first end to a second end and a second surface 72 that is substantially planar and extends from the second end of the first surface, at an internal angle between 90° and 180° to the first surface, to a second end. A second side of the engagement member 5, that faces away from the inner surface 34 of the lip 33 has a first surface 74 which is substantially planar and extends from a first end to a second end substantially in parallel with the first surface 71 of the first side of the engagement member 5, a second surface 75 which extends from the second end of the first surface 74 at an internal angle between 180° and 270° to the first surface 74, to a second end and a third surface 76 that extends from the second end of the second surface 75 to a second end which meets the second end of the second surface 72 of the first side of the engagement member 5, at a substantially acute internal angle to define a wedge shape.

Each of the front 73 and rear surfaces of the engagement member S is provided with a protrusion 77 that is disposed generally centrally on the engagement member 5 approximately midway between the first surface 71 of the first side and the third surface 76 of the second side of the engagement member 5. Each protrusion 77 is generally cylindrical and extends along a longitudinal axis that is substantially perpendicular to the front 73 and rear surfaces of the engagement member 5 respectively.

Each protrusion 77 is received within the second slot 52 of the first and second plates 16, 17 of the coupling member 6 respectively. Opposed, longitudinally extending, sides of each slot 52 form a close fit with the respective protrusion 77 such that each slot 52 forms a guide for the respective protrusion 77 (as discussed in more detail below) as the engagement member 5 moves relative to the coupling member 6.

In Figure 2, the actuation member 4 (the arm 43 and the coupling member 6) and the engagement member 5 are shown in a first position. In Figure 3, the actuation member 4 and the engagement members are shown in a second position.

The rotational spring exerts a biasing torque on the plates 16, 17 of the coupling member 6 in a first direction, which is a clockwise direction about the longitudinal axis of the pin 14 when viewed looking in the direction of figure 3, so as to bias the coupling member 6 into its second position, as shown in figure 3 (as discussed in more detail below).

The weight of the fall arrest traveller 1 and the biasing torque of the rotational spring are selected and arranged such that, as the person travels vertically upwards along the safety line 100, the actuation member 4 and the engagement 5 occupy respective first positions, as shown in Figure 2.

Specifically, when a person moves upwards along the safety line 100 (i.e. the safety line 100 moves relative to the passageway 3 of the fall arrest traveller 1 in a downward direction), the fall arrest traveller 1 is dragged behind the person, due to the weight. The person exerts an upward force on the first end 12 of the arm 43 of the actuation member 4, due to their connection to said first end 12. The weight of the fall arrest traveller 1 acts to produce a downward force on the second end 13 of the arm 43 of the actuation member 4.

The combination of these forces produces a torque on the arm 43 in a second direction which is an opposite direction to the biasing torque produced by the rotational spring, i.e. the combination of these forces produces a torque on the arm 43 in an anti-clockwise direction about the longitudinal axis 50 of the pin 14 when viewed looking in the direction of figure 2. Due to the engagement of the first protrusions 24 of arm 43 with the first ends 54 of the first slots 51 of the coupling plates 16, 17, the arm 43 exerts a torque on the coupling member 6 in said second (anti-clockwise) direction.

The torque exerted on the coupling member 6 by the arm 43 (in the anti-clockwise direction) exceeds the torque exerted on the coupling member 6 by the rotational spring (in the clockwise direction), so as to rotate the coupling member 4 and the arm 43 to their first positions (as shown in Figure 2).

In its first position, the arm 43 is inclined upwardly from the horizontal direction. As the arm 43 moves towards its first position, each first protrusion 24, on the first and second surfaces of the arm 43 respectively, is disposed at the first end 54 of the first slot 51 of the respective coupling plate 16, 17, and moves in an anti-clockwise direction about the longitudinal axis 50 of the pin 14 when viewed looking in the direction of figure 2 against said first end 54. This rotates the coupling plates 16, 17 about the pin 14, in the anti-clockwise direction, against the biasing torque of the spring, from its second position (shown in Figure 3) to its first position (shown in Figure 2).

In this first position, walls of each of the second slots 52 in the coupling member 6 engage the respective protrusions 77 of the engagement member 5, which moves the engagement member 5 away from the safety line 100, to its first position (as shown in Figure 2). In its first position, the engagement member 5 is not in contact with the safety line 100. Accordingly, in this position, the safety line 100 is free to move relative to the passageway 3 in a downwards direction without being engaged by the engagement member 5. This allows the fall arrest traveller 1 to travel upwards along the safety line 100.

The weight of the fall arrest traveller 1 and the biasing torque of the rotational spring are also selected and arranged such that, as the person travels vertically downwards, in a controlled manner, along the safety line 100, the actuation member 4 and the engagement memberS also occupy their first positions, as shown in Figure 2.

Specifically, when a person travels vertically downwards along the safety line 100 (i.e. the safety line 100 is moving in an upwards direction relative to the passageway 3 of the fall arrest traveller 1) in a controlled manner, the fall arrest traveller 1 travels ahead of the person, due to its weight.

The person exerts an upward force on the first end 12 of the arm 43 of the actuation member 4, due to their connection to said first end 12. The weight of the fall arrest traveller 1 acts to produce a downward force on the second end 13 of the arm 43 of the actuation member 4.

The combination of these forces produces a torque on the arm 43 in said second direction, which is an opposite direction to the biasing torque produced by the rotational spring, i.e. the combination of these forces produces a torque on the arm 43, and therefore the coupling member 6, in an anti-clockwise direction about the longitudinal axis 50 of the pin 14 when viewed looking in the direction of figure 2.

The torque exerted on the coupling member 6 by the arm 43 (in the anti-clockwise direction) exceeds the torque exerted on the coupling member 6 by the rotational spring (in the clockwise direction), so as to rotate the coupling member 4 and the arm 43 to their first positions (as shown in Figure 2) This moves the engagement member 5 to its first position, as discussed above, which allows the fall arrest traveller ito travel downwards along the safety line 100.

Referring now to Figure 3, the actuation member 4 (arm 43 and coupling member 6) is shown in its second position. In its second position, the arm 43 of the actuation member 4 is substantially horizontal. The actuation member 4 occupies its second position when the person is substantially vertically aligned with the fall arrest traveller i.

As discussed above, due to the weight of the fall arrest traveller, when a person moves upwards along the safety line iOO, the fall arrest traveller i is dragged behind the person and when a person moves downwards along the safety line 100, in a controller manner, the fall arrest traveller 1 travels ahead of the person. In each case, the fall arrest traveller 1 is slightly below the person.

When the person stops moving on the safety line 100, they manually move the fall arrest traveller 1 upwards along the safety line 100 until it is substantially vertically aligned with them, with the arm 43 substantially horizontal, i.e. until the actuation member 4 is in its second position.

In this case, the biasing torque of the rotational spring (in said clockwise direction) on the coupling member 6 exceeds the torque that is exerted on the coupling member 6 by the arm 43 due to the combination of the weight of the fall arrest traveller and the person (in said anti-clockwise direction) on the first and second ends 12, 13 of the arm 43. Accordingly, the coupling member 6 is rotated to its second position (as shown in Figure 3).

Specifically, as the arm 43 is moved from its first position to its second position, the first protrusions 24 of the arm 43, that are located within the first slots 51 of the coupling member 6 travel in the direction of the generally arcuate axis 56 of the first slots 56. Due to the biasing torque on the coupling member 6, this causes the first ends 54 of each of the first slots 51, which abut said first protrusions 24, to travel with said protrusions 24, until the coupling member 6 reaches its second position.

When the coupling member 6 is in its second position, the second slot 52 in each of the first and second plates 16, 17 of the coupling member 6 is substantially vertical.

The engagement member 5 is urged vertically downwardly under the action of gravity such that the second protrusions 77 of the engagement member 5 are retained at the first end 61 of the respective second slot 52. In this position, the engagement member 5 is in a second position. In this second position, a lower section of the first surface 71 on the first side of the engagement member 5 contacts the safety line 100 (as shown in Figure 3).

When a person begins to fall, the fall arrest traveller 1 falls downwardly along the safety line 100, i.e. the safety line 100 moves relative to the safety line passageway 3 in an upwards direction. Due to the contact of the first surface 71 of the engagement member 5 with the safety line, friction between the safety line and said surface 71 causes the engagement member 5 to move vertically upwards from its second position until it reaches a third position, in which its second protrusions 77 reach the second ends 62 of the second slots 52. As the engagement member 5 moves from its second position to its third position it moves towards the inner surface 34 of the lip 33. The third position of the engagement memberS is shown in figure 4.

As the engagement member 5 moves from its second position to its third position, it translates relative to the actuation member 4, i.e. relative to the coupling member 6 and the arm 43. In addition, as the engagement member 5 translates from its second position to its third position, it rotates about the longitudinal axis of the second protrusions 77 (in an anti-clockwise direction about the longitudinal axis of the second protrusions 77 when viewed looking in the direction of figure 4). Specifically, the second protrusions 77 rotate within the respective second slots 52 of the coupling member 6, as they translate from the first end 61 to the second end 62 of the slot 52, until the first surface 71 of the first side of the engagement member 5 is substantially parallel to the safety line 100 and engages the safety line 100 substantially along the length of said first surface 71, as shown in figure 4.

In this third position, the safety line 100 is clamped between the first surface 71, on the first side of the engagement member 6 and the inner surface 34 of the lip 33 that defines the passageway 3. This stops the movement of the safety line 100 relative to the passageway 3 and so slidably locks the f all arrest traveller 1 onto the safety line 100, thereby arresting the fall of the person attached to the actuation member 4 of the fall arrest traveller 1.

The actuation member 4 is movable from its second position to a third position in which it engages the engagement member 5 so as to increase the force of engagement of the engagement member 5 with the safety line lOft Specifically, when the safety line 100 is clamped by the movement of the engagement member 5 to its third position, this causes the person to overtake the fall arrest traveller 1, which moves the arm 43 of the actuation member 4 downwardly from its second position to a third position (in a clockwise direction about the longitudinal axis 50 of the pin 14 when viewed looking in the direction of figure 4), which is shown in figure 4. In the third position, the arcuate protrusion 93 of the arm 43 is received within a groove defined between the first and second surfaces 74, 75 on the second side of the engagement member 5 and abuts said surfaces 74, 75 so as to increase the force of engagement of the engagement member S with the safety line 100, i.e. it acts to urge the engagement member 5 towards the inner surface 34 of the lip 33. In this position (i.e where the arm 43 is in its third position), the actuation member 4 is in a third position.

When the engagement member 5 moves from its second position to its third position, the first surface 76 of the second side of the engagement member 5 slidably bears against the pin 14. Accordingly, as the engagement members moves from its second position to its third position, the force of engagement of the engagement member 5 with the safety line 100, exerted on the engagement member 5, acts through the longitudinal axis 50 of the pin 14. This is advantageous in that the force of engagement does not create a bending moment on the actuation member 4, about said axis 50.

When the arm 43 is between its third position and its second position, it doesn't act to urge the coupling member 6, or the engagement member 5, to its first position. This is advantageous as it provides a person, who is attached to the fall arrest traveller 1, with some degree of freedom of movement, without the fall arrest traveller 1 being disengaged, i.e. without the engagement member 5 moving from its second position to its first position.

Since, when it is in its second position, the engagement member 5 contacts the safety line 100 such that slidable movement of the fall arrest traveller 1 downwardly along the safety line 100 causes the engagement memberS to engage the safety line 100, the engagement of the engagement member 5 with the safety line 100 is dependent on the movement of the fall arrest traveller 1 downwardly along the safety line 100. Accordingly, the engagement is not dependent on the speed or direction of fall of a person relative to the fall arrest traveller 1, but is dependent on the speed of fall of the fall arrest traveller 1 along the safety line 100. This prevents a person from falling a dangerous distance before the fall arrest traveller 1 locks onto the safety line 100.

In this respect, when the actuation member 4 is moved to its second position, it automatically engages the safety line 100 as soon as the fall arrest traveller 1 moves downwardly along the safety line 100. Accordingly the fall arrest traveller 1 locks onto the safety line 100 as soon as a person begins to fall.

Furthermore, since the engagement member 5 is movable relative to the actuation member 4, from its second position to its third position, the engagement of the engagement member 5 with safety line 100 is not dependent on how far the actuation member 4 moves from its second position, towards its third position, nor the force with which the actuation member 4 moves. Therefore, the locking of the fall arrest traveller 1 on the safety line is not dependent of the speed or direction of fall of the person relative to the fall arrest traveller 1.

The described and illustrated embodiments are to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiments have been shown and described and that all changes and modifications that come within the scope of the inventions as defined in the claims are desired to be protected.

For example, in the described embodiment the safety line is substantially vertical.

However, it will be appreciated that the safety line may be oriented in any upwardly extending direction (i.e. inclined relative to the horizontal direction) and the invention is not limited to where the safety line is substantially vertical.

In the described embodiment the arm 43 is provided with first protrusions 24 which are respectively received within the first slots 51 of the coupling member 6. However, it will be appreciated that the invention is not limited to this arrangement and the reciprocal arrangement may be used where the first slots 51 are provided in the arm 43 and the first protrusions 24 are provided on the first and second plates 16, 17 of the coupling member 6.

Similarly, in the described embodiment the engagement member 5 is provided with second protrusions 77 which are respectively received within the second slots 52 of the coupling member 6. However, it will be appreciated that the invention is not limited to this arrangement and the reciprocal arrangement may be used where the second slots 51 are provided in the engagement member 5 and the second protrusions 77 are provided on the first and second plates 16, 17 of the coupling member 6.

It should be understood that while the use of words such as "preferable", "preferably", "preferred" or "more preferred" in the description suggest that a feature so described may be desirable, it may nevertheless not be necessary and embodiments lacking such a feature may be contemplated as within the scope of the invention as defined in the appended claims. In relation to the claims, it is intended that when words such as "a," "an," "at least one," or "at least one portion" are used to preface a feature there is no intention to limit the claim to only one such feature unless specifically stated to the contrary in the claim. When the language "at least a portion" and/or "a portion" is used the item can include a portion and/or the entire item unless specifically stated to the contrary.

Claims

CLAIMS: 1. A fall arrest traveller for slidable attachment to a safety line comprising a passageway for a safety line, an actuation member for connection to a person and an engagement member for selective engagement with a safety line received within said passageway, the actuation member is arranged such that it occupies a first position when a person connected to the actuation member is travelling upwardly or downwardly along the safety line and is coupled to the engagement member such that when the actuation member is in its first position, the engagement member occupies a first position in which it allows slidable movement of the fall arrest traveller upwardly or downwardly along the safety line and when the actuation member is in a second position the engagement member occupies a second position in which it contacts the safety line, wherein the engagement member is movable relative to the actuation member from its second position to a third position and is arranged such that slidable movement of the fall arrest traveller downwardly along the safety line causes the engagement member to move from its second position to its third position in which it engages the safety line so as to slow down or stop movement of the fall arrest traveller downwardly along the safety line.
2. A fall arrest traveller according to claim 1 wherein the actuation member is arranged such that it occupies its first position when a person connected to the actuation member travels upwardly and downwardly along the safety line.
3. A fall arrest traveller according to claim 2 wherein when the engagement member is in its first position, it allows slidable movement of the fall arrest traveller upwardly and downwardly along the safety line.
4. A fall arrest traveller according to any preceding claim wherein when the engagement member is in its first position, it is spaced from the safety line such that it does not contact the safety line.
5. A fall arrest traveller according to any preceding claim wherein the actuation member is biased into its second position by a biasing member.
6. A fall arrest traveller according to claim 5 wherein the weight of the fall arrest traveller and the biasing member are arranged such that as the person travels upwardly or downwardly along the safety line, the actuation member occupies its first position.
7. A f all arrest traveller according to claim 6 when dependent on claim 2 wherein the weight of the fall arrest traveller and the biasing member are arranged such that as the person travels upwardly and downwardly along the safety line, the actuation member occupies its first position
8. A fall arrest traveller according to any preceding claim wherein the actuation member comprises an arm for connection to a person and a coupling member which couples the arm to the engagement member.
9. A fall arrest traveller according to claim 8 wherein the passageway for the safety line extends in a longitudinal direction and the actuation member is arranged such that, when it is in its first position, its arm is inclined relative to an axis that is substantially perpendicular to said longitudinal direction.
10. A fall arrest traveller according to either of claims 8 or 9 wherein the passageway for the safety line extends in a longitudinal direction and the actuation member is arranged such that when it is in its second position, its arm is substantially perpendicular to said longitudinal direction.
11. A fall arrest traveller according to any of claims 8 to 10 wherein when the actuation member is in its first position, the arm and coupling member occupy a first position and when the actuation member is in its second position, the arm and coupling member occupy a second position.
12. A fall arrest traveller according to any of claims 8 to 11 when dependent on claim 5 wherein the coupling member is biased into its second position by the biasing member.
13. A fall arrest traveller according to any preceding claim wherein the actuation member is movable from its second position to a third position in which it engages the engagement member so as to increase the force of engagement of the engagement member with the safety line.
14. A fall arrest traveller according to claim 8 or any of claims 9 to 13 when dependent on claim 8 wherein the arm is movable relative to the coupling member from its second position to a third position such that when the actuation member occupies its second and third positions, the arm occupies its second and third positions.
15. A fall arrest traveller according to claim 14 wherein one of the arm and the coupling member is provided with a first protrusion and the other of the arm and the coupling member is provided with a first slot, wherein the first protrusion is slidable within the first slot such that the arm is movable relative to the coupling member between its second and third positions.
16. A fall arrest traveller according to claim 11 or any of claims 12 to 15 when dependent on claim 11 wherein when the arm is in its first position, the first protrusion engages the first slot such that the coupling member is moved to its first position.
17. A fall arrest traveller according to claim 11 or any of claims 12 to 16 when dependent on claim 11, wherein when the arm is in its second position, the first protrusion engages the first slot such that the coupling member is moved to its second position.
18. A fall arrest traveller according to any preceding claim wherein one of the actuation member and the engagement member is provided with a second protrusion and the other of the actuation member and the engagement member is provided with a second slot and the second protrusion is slidable within the second slot such that the engagement member is movable relative to the actuation member between its second and third positions.
19. A fall arrest traveller according to any preceding claim wherein the actuation member is rotatably mounted to a pivot member such that it is rotatable from its first position to its second position about an axis.
20. A fall arrest traveller according to claim 19 wherein the engagement member is arranged such that as the engagement member moves from its second position to its third position, the force exerted on the engagement member, when it engages the safety line, acts through said axis.
21. A fall arrest system comprising an upwardly extending safety line attached to a structure, a harness for a person and a fall arrest traveller according to the first aspect of the invention, wherein the fall arrest traveller is slidably attached to the safety line and the harness is attached to the actuation member of the fall arrest traveller.
22. A fall arrest traveller substantially as described herein, with reference to the accompanying drawings.
23. A fall arrest system substantially as described herein, with reference to the accompanying drawings.