EP2641635A2

EP2641635A2 - Back-up apparatus for use in rope access

Info

Publication number: EP2641635A2
Application number: EP13159866.6A
Authority: EP
Inventors: Frederick Allan Hall; Robert Stephen Farrer
Original assignee: DMM International Ltd
Current assignee: DMM International Ltd
Priority date: 2012-03-20
Filing date: 2013-03-19
Publication date: 2013-09-25
Also published as: GB2500483B; GB201204845D0; GB201304959D0; GB2500483A; EP2641635A3

Abstract

Back-up apparatus for use in climbing comprising is disclosed. It has particular application to rope access climbing, but may find application in other fields. The apparatus includes a slider (22) that can be applied to a back-up line (20). The slider has an attachment formation (38) by which it can be connected to a lanyard (32). The slider (22) is operative, upon application of a load on a downward direction through a lanyard so connected, to grab onto a line to which it is applied. A drawing line (40) is connected to the slider (20) by which it the slider may be drawn downwardly along a line to which it is applied. A handle (42) connected to the drawing line (40) that can be grasped by a climber, the handle having a release means that can be operated by a climber to cause the handle to release its connection with the drawing line.

Description

This invention relates to a back-up system and apparatus for use in rope access, work at height or climbing. It has particular, but not exclusive, application to a back-up system and apparatus for use in rope access climbing.
Rope access climbing involves the use of a variety of techniques to enable access to high places including manufactured structures and trees. In general, a rope access technician (referred to for convenience as a "climber" in this specification) uses a rope adjustment device to ascend and descend a working line (in practice, where possible, in rope access, the climber will start at the top of their working line and then work downwards). Since the climber is entirely dependent upon the working line for support (in contrast to a rock climber, whose rope is intended for protection in a fall only) an additional back-up line is provided to catch the climber in the event of a failure of the working line or associated apparatus.
Clearly, there is a requirement that the climber is connected to the back-up line in such a way as to allow their unimpeded movement up and down the working line, while arresting a fall as quickly as possible.
There are many known forms of back-up devices. However, what they have in common is that they attach the climber to a back-up line by some form of lanyard.
EP-A-1 525 903 discloses a fall-arrest device for use on a rope that has a roller to engage a rope. In the event that the rotational speed of the roller exceeds a threshold, a centrifugal coupling device operates to inhibit rotation of the roller, and thereby prevent further movement of the device on the line.
One further known form of back-up device uses frictional engagement with a rope such that it is free to move upwards upon a line, but which is twisted to lock itself onto the line when loaded through a lanyard attached to the device. This is advantageous because it locks quickly and is a simple device. In order to move the device down the line, it must be pivoted in a direction opposite to that in which it is twisted under a downward load by the lanyard. It is common to provide an eye in the device to which a cord can be attached to "tow" the device down the line. This is effected by positioning the eye such that it causes the device to twist in the required direction when the cord is pulled downwardly. For convenience, a climber may hold, tie or wrap an end of the cord to his or her wrist or finger. However, this presents a major safety risk. If the climber does not quickly release the cord in the event of a fall, the device will not arrest their movement. For this reason, towing the device in this manner is not a formally recommended way in which to use the device.
An aim of this invention is to provide a back-up device that is simple, reliable and safe.
To this end, the present invention provides back-up apparatus for use in rope access comprising: a slider that can be applied to a back-up line, the slider having an attachment formation by which it can be connected to a lanyard, and the slider being operative, upon application of a load on a downward direction through a lanyard so connected, to grab onto a line to which it is applied; a drawing line connected to the slider by which it the slider may be drawn downwardly along a line to which it is applied; and a handle connected to the drawing line that can be grasped by a climber, the handle having a release means that can be operated by a climber to cause the handle to release its connection with the drawing line.
The handle provides for the climber a firm and secure grip on the drawing line allowing it to be used to draw the slider down a back-up line in normal use. In the event of failure of a working line, or an uncontrolled descent arising for any other reason, the climber can either release entirely his or her grip on the handle or operate the release means to disconnect the handle from the drawing line, thereby allowing the slider to operate to arrest the climber's fall.
The release means may include a press-button that is carried on a body of the handle. This can be treated as a "panic button" by the climber for activation of the device in response to an event that requires immediate activation, for instance the occurrence of an uncontrolled descent.
Alternatively, the release means may include a lever that is pivotally connected to a body of the handle. In a typically embodiment, displacement of a projecting part of the lever into the body causes the handle to release its connection with the drawing line. In such cases, the said displacement can be accomplished by an increase of strength of a user's grip on the handle. A natural reaction of a person who encounters an unexpected danger, such as the failure of a support line, is to increase their grip on anything that they might be holding. In these embodiments, such a reaction will cause the desired release of the draw line, so bringing the backup apparatus into operation to prevent a fall.
The handle is preferably additionally connected to the slider by a tether. This ensures that the handle will not be lost after operation of the release means. The secondary tether is most preferably connected to the slider adjacent to the attachment means. This ensures that any load applied to the slider by the tether enhances emergency operation of the slider. The secondary tether may be sufficiently long that it remains slack when a climber is supported from the slider by a lanyard to ensure that it is slack when the climber is being supported by the slider. This ensures that it applies no significant force to the slider as might prevent its proper operation. Conveniently, the secondary tether may be coiled upon the drawing line for normal use.
In an alternative arrangements, the back-up apparatus includes a secondary tether that connects the handle to a lanyard that is secured to the attachment formation or to an operator's body or item of clothing.
The drawing line may take many forms - it may be flexible, rigid, or resilient. For example, it may include a length of cable to which a ferrule is connected, the ferrule by which it can be connected to the handle.
In preferred embodiments, the slider includes a cam that is forced, on application of a load to the connection formation, into contact with the back-up line. In such embodiments, the drawing line may be connected to the cam.
From a second aspect, this invention provides an installation for use in rope access climbing that includes a back-up line to which is applied back-up apparatus embodying the first aspect of the invention and a working line on which is carried a rope adjustment device that serves as a primary support for a climber during normal use.
In an alternative arrangement, the invention provides an installation for use in rope access climbing that includes a back-up line to which is applied back-up apparatus, a working line on which is carried a rope adjustment that serves as a primary support for a climber during normal use, and a secondary tether that connects the handle to the lanyard.
The rope adjustment device may include an operating handle that includes a formation within which the handle of the back-up apparatus can be retained by a user's grip.
From a third aspect, the invention provides a method of operating a rope access climbing system that includes providing a slider that can be pulled down a back-up line by a drawing line, providing a handle on the drawing line, providing release means, operation of which disconnects the handle from the drawing line, in which, in normal use, as a climber ascends and/or descends a working line the climber uses the handle to pull the drawing line to draw the slider down the back-up line, and in the event of the climber being subject to an uncontrolled descent, the climber operates the release means or releases grip of the handle whereby the slider ceases to be pulled by the drawing line and can then grab the back-up line to arrest the climber's descent.
In preferred embodiments, the climber operates the release means by increasing the force of their grip on the handle.
Embodiments of the invention will now be described in detail, by way of example, with reference to the accompanying drawings, in which:

Figure 1 shows a rope access climbing system embodying the invention;
Figures 2 and 3 are side and front views of a back-up arrangement of the system of Figure 1;
Figure 4 is a side view of a handle assembly being part of the embodiment of Figure 1;
Figure 5 is a sectional view of the handle assembly of Figure 4 in a closed condition;
Figure 6 is a sectional view of the handle assembly of Figure 4 in a released condition;
Figure 7 is an end view of the handle assembly of Figures 4 to 6;
Figure 8 is a side view of a back-up arrangement of being a second embodiment of the invention;
Figure 9 is a side view of a back-up arrangement of being a third embodiment of the invention;
Figures 10 and 11 are side and front views of a back-up arrangement of the embodiment of Figure 9;
Figure 12 is a side view of a handle assembly of the embodiment of Figure 9;
Figure 13 is a sectional view of the handle assembly of Figure 12 in a locked condition;
Figure 14 is a sectional view of the handle assembly of Figure 12 in an unlocked condition; and
Figure 15 is a sectional view of the handle assembly of Figure 12 having released a drawing line.

With reference first to Figure 1, a rope access system includes a working line 10 and a rope adjustment device 12 on the working line 10. The rope adjustment device 12 includes an operating handle 14 that is grasped by a climber and moved to a descent position in which the climber is allowed to descend the working line 10 in a controlled manner. As discussed so far, these components may be conventional. In this embodiment, an elongate recess 16 is formed in the operating handle 14, the purpose of which will be described in due course.
In addition, the rope access system includes a back-up arrangement, also shown in Figures 2 and 3. This comprises a back-up line 20 that is independent of the working line. A slider 22 is carried on the back-up line. The slider 22 has a pivotable cam 24 and a cylindrical abutment 26 carried within a body 28.
The cam 24 is carried on a pivot 30 so that it can pivot about an axis with respect to the body 28. The axis is parallel to one another. The abutment 26 has an axis that is generally parallel to the axis of rotation of the cam 24. The cam 24 can rotate such that a curved camming surface 34, intersected by the plane of rotation, can move towards and away from the abutment 26. In the orientation shown in Figure 3, the camming surface forms part of a helix that increases in radius in a clockwise direction. A bias spring urges the cam 24 to rotate such that the camming surface 34 is urged towards the abutment 26.
A securing eye 38 is formed as an aperture that extends through the body 28 in a direction parallel to the axes of the cam 24 and the abutment 26, the eye 38 being positioned such that it is possible to construct a right-angled triangle that has its right angle on the axis of the abutment 26, its adjacent side a line connecting the axes of the cam 24 and the abutment 26, and its hypotenuse connecting the axis of the cam 24 and an approximately central point of the eye 38. The eye 38 is intended to receive a connector 18 such as a carabiner to that connects the body 28 to a lanyard 32 that is, in turn, secured by a second connector 36 to a harness worn by a climber.
A rope passage extends through the body 28. The back-up line 20 is passed though the rope passage for use, such that it passes downwardly, past the eye 38, between the cam 24 and the abutment 26, the rope being centred approximately in the cam's plane of rotation. Within the plane of rotation, the abutment 26 and the eye 38 are to one side of the back-up line 20 and the cam 24 is to the other. In this embodiment, the body 28 is formed from two spaced plates that can pivot with respect to one another about the axis of the cam 24. This allows the body to be opened to allow the back-up line 20 to enter the rope passage. The plates are then pivoted to a closed position (as shown in the drawings). A connector 18 that has been placed through the eye 38 prevents the plates opening so retaining the rope within the body.
A draw cable 40 is attached to the cam 24 close to an end part of the camming surface 34 remote from the pivot 30. Remote from the cam 24, the draw cable 40 is terminated with a metal ferrule 41. A circumferential groove 44 is formed in the ferrule 41 and a portion of the ferrule 41 between the groove 44 and the end is tapered.
Remote from the body 28, the draw cable 40 is connected to a handle assembly 42, shown in Figures 4 to 7. The handle assembly 42 comprises a tubular body 46 that has an outer surface that is shaped so that it can be gripped comfortably by a climber. A bore 48 extends diametrically through the body 46. A clamp mechanism, that includes locking bar 50, is contained within the body 46 and can slide within it in a direction normal to the bore 48. A biasing spring 54 acts to urge the locking bar towards a closed end of the body 46. A stepped bore is formed transversely through the locking bar 50. When the locking bar 50 moves to the extreme of its travel under the action of the spring 54, the stepped bore has an axis that is parallel to but spaced from the bore 48 that extends through the body.
If the ferrule 41 is pushed into the bore 48, the tapered end enters the bore of the locking bar, and pushes the locking bar 50 aside against the action of the spring 54. The ferrule 41 can continue to slide into the bore until the groove 44 is adjacent to the step in the bore of the locking bar 50, whereupon the step in the bore of the locking bar 50 springs into the groove 44, as shown in Figure 5, thereby clamping the ferrule 41 within the body 46, resisting its removal or further insertion.
The handle assembly 42 also includes a release button 52 that is connected to the locking bar 50. A user can apply a force to the release button 52 to cause the locking bar 50 to move against the action of the spring 54 such that the bores in the locking bar 50 and the body come nearer to being coaxial, as shown in Figure 6. This removes the step in the bore from the groove 44, so releasing the grip of the locking bar on the ferrule 41. The ferrule 41 can then be freely removed from the handle assembly 42, so disconnecting the handle assembly 42 from the draw cable 40.
A secondary connection tether 56 connects the handle assembly 42 to the body 28, the connection being made close to the abutment 26 - that is, on the opposite side of the rope to the draw cable 40. The tether 56 is substantially longer than the draw cable 40. In this embodiment, this is achieved by forming the secondary connection cord 56 from lightweight, resilient material that is formed into a long coil surrounding the draw cable 40, an arrangement that is adopted for neatness, to minimise the likelihood it will become tangled or caught in use.
Operation of the system will now be described.
The essential characteristic of the slider 22 is that it tends to grab the line on which it is installed when a downward force is applied to it through the eye 38. It will be seen that such a force will cause it to rotate in a clockwise direction in the illustration of Figure 3, so that the abutment 26 forces the line 20 into contact with the camming surface 34 of the cam 24. As the downward force increases, the cam 24 tends to rotate anti-clockwise, thereby reducing the spacing between the camming surface 34 and the abutment 26, so increasing its grip on the line 20. On the other hand, if an upward force is applied to the slider 22 through the eye 38, the opposite effects take place, with the result that the slider 22 can slide up the line 20 relatively freely. Thus, when ascending a working line 10, a climber has the option of simply dragging the slider up the back-up line 20 by the lanyard 32.
Many climbers prefer to work with the slider 22 above them. This allows them to see that it is in place, and will minimise the distance they fall in the event of an uncontrolled descent, such as through failure of their working line 10. This can be achieved by pulling the slider 22 upward using the lanyard 32 and downward using the draw cable 40. The effect of the bias spring on the cam 24 is to provide a light grip on the back-up rope 20 to prevent the slider 22 descending under its own weight when it is not loaded through the lanyard 32. The handle assembly 42 provides a convenient grip for the draw cable 40. The position of the attachment of the draw cable 40 to the body 28 means that it can be used to draw the slider down the back-up line 20. When the draw cable 40 is pulled down, it causes the body to rotate anti-clockwise (in the orientation of Figure 3) thereby pulling the abutment 26 away from the back-up line 20. For the convenience of the climber, the handle assembly 42 can be placed into the recess 16 in the operating handle 14 of the rope adjustment device 12, where it is held by the climber's grasp of the operating handle 14. The climber's thumb is placed on or next to the release button 52. In this way, the slider 22 will be drawn down the backup line 20, being pulled by the draw cable 40 through the handle assembly 42 when the climber operates the operating handle 14.
Now, consider what happens in the event of an uncontrolled descent such as through failure of the working line 10. When the climber starts to fall, it is vital that the slider 22 locks promptly onto the back-up line 20. The simplest way to ensure that this happens is for the climber simply to let go of the operating lever 14 so releasing the handle assembly 42. However, this is not an entirely natural reaction, especially for a climber of relatively little experience. Therefore, the alternative is for the climber to press the release button 52, so disconnecting it from the draw cable 40, and allowing the slider to lock onto the back-up line 20. Unlike simply letting go, this is a positive action: something that is more natural in a situation of panic. The tether 56 prevents loss of the handle assembly 42, but its additional length, and its connection point to the body 28, is such that it will not be able to tow the slider 22 down the back-up line 20.
It is important to realise that this arrangement allows a climber to tow their back-up slider 22 safely as they move up and down the working line 10. This means that panic button operation can become an additional part of accepted procedure and taught to climbers, as an alternative or addition to releasing the drawing line, as part of their training.
An alternative arrangement of a back-up assembly embodying the invention is shown in Figure 8. The difference between this embodiment and that of Figures 1 to 7 lies in the configuration of the tether. In this embodiment, the tether 60 connects the handle assembly 42 to the lanyard 32 close to the connector 18. The tether is illustrated as formed from a tape, but a cord could be used instead. In the event of an uncontrolled descent, the climber has the option of pressing the release button 52 or letting go of the handle assembly 42. If the user takes the former action, any load that is transmitted by the climber's grip on the handle assembly 42 to the tether supplements the load from the lanyard 32, thereby enhancing the grip of the slider 22 on the back-up line 20,
Embodiments of the invention can use a conventional lanyard formed from a single length of rope, webbing or other suitable material. As shown in these embodiments, the lanyard is formed from two lengths (in these examples, of webbing) interconnected by a metal ring 62. In the event that a climber has to be rescued following an incident that leaves the climber supported by the lanyard, the ring can be used as a connection point to which additional equipment can be connected to raise or lower the climber safely to a place of rescue.
With reference now to Figure 9, a third embodiment of the invention will now be described.
This embodiment includes a slider 22 that is carried on a rope 20 and that is connected to a lanyard 32, as in the embodiments described above. These will not be described here again.
Remote from the body 28, the draw cable 140 is connected to a handle assembly 42, shown in Figures 4 to 7. The draw cable 140 is attached to the cam 24 close to an end part of the camming surface 34 remote from the pivot 30. Remote from the cam 24, the draw cable 140 is terminated with a metal ferrule 141. The draw cable 140 of this embodiment is shorter than that of the embodiments described above, being approximately 10 mm in length.
The ferrule 141 is a generally cylindrical metal body that surrounds an end part of the draw cable 140. A free end part of the ferrule (remote from the cam) is slightly tapered, while the opposite end of the ferrule is formed with a shoulder that extends perpendicular to the length of the draw cable 140.
The handle assembly comprises a body 160 and a lever 162, and has a connection end and a free end. The body 160 is an elongate component with a generally U-shaped cross-section, such that an internal channel extends along its length. Externally, the body 160 has a concave curve along its length and a transverse convex curve that is formed by the base of the U-shape. The shape and size of the body 160 is chosen such that it can be comfortably held in a user's hand.
The lever 162 is formed as an elongate bar with a broadened transverse end portion 164 close to the free end. The lever 162 partially retained within the channel of the body 160 and partially projects from it. The end portion 164 has a transverse size that prevents it from entering into the channel of the body 160. The lever 162 is connected to the body 160 by a pivot pin 164 that extends transversely across the channel though a hole in the lever 162 approximately two-thirds of the distance from the free end to the connection end. A compression spring 166 is located within a blind bore in the release lever 162 close to its broadened end portion 164 and bears against a recess in the channel of the body 160. The spring 166 biases the lever 162 towards a closed position.
Opening axially at the connection end, a recess 170 is formed transversely across the lever 162. An abutment 172 extends across it the recess 170 at the connection end, the abutment 172 having a height approximately one quarter the depth of the recess 170.
A secondary connection tether 156 connects the handle assembly 42 to the body 28, the connection being made close to the abutment 26 - that is, on the opposite side of the rope to the draw cable 140. An longitudinal bore 174 passes through the lever 162 from the free end to a recess 176 adjacent to the pivot pin 164, the secondary connection tether 156 being passed through the bore 174 and secured by a knot that is received in the recess 176.
For use, the draw cable 140 is connected to the handle assembly 142 by pushing the ferrule 141 into the recess. The taper of the ferrule 141 is dimensioned to pass closely between the abutment 172 and an adjacent part of the body 160 when the lever 162 is in the closed position. The action of the taper 162 causes the lever to be deflected from the closed position, thereby allowing the ferrule 141 to pass the abutment 172 and thereby enter the recess 170, as shown in Figure 13. Once the ferrule 141 has passed the abutment 177, the spring 166 urges the lever 162 back to the closed position, which causes the abutment to pass behind the shoulder of the ferrule 141, thus retaining it within the recess 170, thereby connecting the draw cable 140 to the handle assembly 142.
In this condition, a user can grasp the handle assembly 142 and pull upon it to draw the slider 22 down the backup line 20, and use the lanyard to draw the slider 20 up the backup line 20, allowing the user to work normally as described above.
In the event of an uncontrolled descent such as through failure of the working line 10, as in the embodiments described above, the user can simply to let go of the handle assembly 142. Alternatively, a natural reaction from an inexperienced climber is to grip the handle assembly 142 more tightly - a "death grip" that can occur as a result of panic. This causes the lever 162 to be deflected about the pivot pin 164 against the force of the spring 166 to a release position, which causes the abutment 172 to move away from the adjacent part of the body 160, as shown in Figure 14. In the release position, the ferrule 141 can pass out of the recess 170 by the abutment 172, thereby disconnecting the handle assembly 142 from the draw cable 140, as shown in Figure 15. The slider 22 will then grip the backup rope 20 so arresting the climber's fall. The secondary connection tether 156 prevents the handle assembly 142 from falling free when it has been released from the draw cable 140.
As with the other embodiments, this arrangement allows a climber to tow their back-up slider 22 safely as they move up and down the working line 10. Emergency operation of the lever 162 can become an additional part of accepted procedure and taught to climbers, as a natural alternative or addition to releasing the drawing line, as part of their training.

Claims

Back-up apparatus for use in rope access comprising:
a slider (22) that can be applied to a back-up line (20), the slider having an attachment formation (38) by which it can be connected to a lanyard (32), and

the slider being operative, upon application of a load on a downward direction through a lanyard so connected, to grab onto a line to which it is applied;

a drawing line (40; 140) connected to the slider by which it the slider may be drawn downwardly along a line to which it is applied; and characterised by

a handle (42; 142) connected to the drawing line (40; 140) that can be grasped by a climber, the handle having a release means that can be operated by a climber to cause the handle to release its connection with the drawing line.
Back-up apparatus according to claim 1 in which the release means includes a press-button (52) that is carried on a body of the handle.
Back-up apparatus according to claim 1 in which the release means includes a lever (162) that is pivotally connected to a body (160) of the handle.
Back-up apparatus according to claim 3 in which displacement of a projecting part of the lever (162) into the body (160) causes the handle (142) to release its connection with the drawing line (140).
Back-up apparatus according to claim 4 in which the said displacement can be accomplished by an increase of strength of a user's grip on the handle.
Back-up apparatus according to any preceding claim in which the handle is connected to the slider adjacent to the attachment formation by a secondary tether (56; 156).
Back-up apparatus according to any one of claims 1 to 5 that includes a secondary tether (60) that connects the handle (42; 142) to a lanyard (32) that is secured to the attachment formation.
Back-up apparatus according to any preceding claim in which the attachment formation is an eye (38) to which a lanyard can be attached through a connector (18).
Back-up apparatus according to any preceding claim in which the slider includes a cam (24) that is forced, on application of a load to the connection formation, into contact with the back-up line.
Back-up apparatus according to claim 9 in which the drawing line is connected to the cam (24).
An installation for use in rope access climbing that includes a back-up (20) line to which is applied back-up apparatus according to any preceding claim and a working line (10) on which is carried a rope adjustment device (12) that serves as a primary support for a climber during normal use.
An installation for use in rope access climbing that includes a back-up line (20) to which is applied back-up apparatus according to any one of claims 1 to 5, a working line (10) on which is carried a rope adjustment device (12) that serves as a primary support for a climber during normal use, and a secondary tether that connects the handle to the lanyard.
An installation according to claim 11 or claim 12 in which the rope adjustment device (12) includes an operating handle (16) that includes a formation within which the handle of the back-up apparatus can be retained by a user's grip.
A method of operating a rope access climbing system that includes providing a slider (22) that can be pulled down a back-up line (20) by a drawing line (40; 140), providing a handle (42; 142) on the drawing line, providing release means, operation of which disconnects the handle from the drawing line, in which, in normal use, as a climber ascends and/or descends a working line, the climber uses the handle to pull the drawing line to draw the slider down the back-up line, and in the event of the climber being subject to an uncontrolled descent, the climber operates the release means or releases grip of the handle whereby the slider ceases to be pulled by the drawing line and can then grab the back-up line to arrest the climber's descent.
A method according to claim 14 in which the climber operates the release means by increasing the force of their grip on the handle.