WO2007045855A2

WO2007045855A2 - Descender

Info

Publication number: WO2007045855A2
Application number: PCT/GB2006/003855
Authority: WO
Inventors: Christopher Mark Edmondson
Original assignee: The Heightec Group Ltd
Priority date: 2005-10-21
Filing date: 2006-10-18
Publication date: 2007-04-26
Also published as: GB0521432D0; WO2007045855A3; GB2431456A; EP1948321A2

Abstract

A descender provides a reduced friction configuration to ease the passage of the rope when it is under light tension, the rope passing around a locking means comprising eccentric cam (1) and abutments (10) and (11) , and an increased friction configuration where the rope additionally passes around abutments (2) and (18). The rope can be passed from one configuration to the other whilst the load is held by the locking means. Preferably the abutments and cam are mounted on a plate (5) with a pivotally mounted cover plate (6, fig 1 ) which can be moved between a rope loading/unloading position and a closed position where it retains the rope in the locking means. Preferably, the control handle (12) has a further protruberance (13) to coact with the abutment (11) to jam the rope.

Description

Descender

Double braking descenders - those which lock if they are released or the operating means is over operated in panic, are well known for abseiling etc. Due to the mechanism of such devices it is very difficult to pay out rope when not under full body weight. This function is important when the user approaches an edge along flat or lightly angled ground. The descender is normally attached to the rope well away from the edge to prevent the user falling over it. However for the user to approach the edge they must obviously pay rope through the descender, existing descenders provide sufficient friction for the user to descend vertically so that when the user does not have his/her full weight on the descender movement is very difficult. This problem is further compounded by the double brake mechanism as it is particularly difficult to find the minimum friction position i.e. when the first brake is off but before the second brake has started to come on. Many of such devices have an additional problem in that the braking mechanism prevents slack rope between the descender and the anchor point (of the rope) from being removed/taken in in one action. Taking in slack involves pulling a loop out of one part of the descender then feeding it back through another (if it is possible at all).

According to the present invention there is provided a descender for controlling the lowering and/or raising of a load on a rope, the descender comprising rope guide means for guiding and controlling the passage of a rope through the descender and attachment means for attaching the descender to a further rope and/or an object/person to be lowered and/or raised, the rope guide means includes locking means comprising a first locking member moveable between a rope jamming position wherein the rope is trapped between the locking member and an adjacent abutment and a release position wherein the locking member is spaced from said abutment, the rope guide means being arranged such that the first locking member is urged towards its rope jamming position when a load is applied to a downstream end of the rope, the first locking member being selectively moveable towards its release position in order to selectively control the movement of the rope through the rope guide means, wherein the rope can be mounted in the rope guide means in two operative configurations, a first configuration for controlled lowering/raising a load and a second configuration wherein the rope can move through the rope guide means with less resistance to movement than when in the first configuration for easing the passage of rope through the descender when the rope is under light tension to assist adjustment of slack or when paying out rope under light tension, wherein the rope can be moved between its first and second operative configurations without removing the rope from the locking means.

Preferably the rope guide means comprises a pulley and a bollard, the rope passing around the pulley and between the pulley and the bollard only when the rope is in its first configuration. Preferably the pulley is non-rotatable whereby the rope must slide around the pulley when the rope is in its first configuration.

Preferably, the descender comprises a first mounting plate, the rope guide means being mounted on the first mounting plate, a second mounting plate being mounted on the first mounting plate for movement between a rope loading position wherein the rope can be located in the rope guide means in either its first or second operative configurations and a closed position wherein the second mounting plate covers at least the gap between the first locking member and its adjacent abutment, preventing removal of rope from the locking means, the second mounting plate being shaped to allow the rope to be moved between its first and second operative configurations while the second mounting plate is in its closed position. Preferably the first locking member is moveable towards its release position by a control lever. Preferably the locking means comprises a second locking member, the second locking member being mounted on and/or actuated by said control lever and being co-operable with a second abutment, the second locking member being moveable between a rope jamming position wherein the rope is trapped between the second locking member and the second abutment and a release position wherein the second locking member is spaced from said second abutment. Preferably the control lever has three operative positions, a first position wherein the rope is trapped between the first locking member and its adjacent abutment and the second locking member is spaced from the second abutment, a second, intermediate, position wherein both the first and second locking members are spaced from their respective abutments to permit passage of the rope through the rope guide means, and a third position wherein the rope is trapped between the second locking member and the second abutment and the first locking member is spaced from its adjacent abutment.

Preferably the first locking member comprising a first cam or eccentric pulley pivotably mounted on the first mounting plate for rotation about a rotational axis normal to said first mounting plate between its rope jamming position and its release position, said adjacent abutment being mounted on and extending from said first backing plate.

An embodiment of the present invention will now be described by way of example only, and with reference to the accompanying drawings in which:

Figure 1 is a front view of the descender according to the invention.

Figure 2 is a front view of Fig.1 with the cover plate removed and with the primary braking mechanism in a first operative position to lock the descender onto the rope and the secondary braking mechanism in a first operative position free of the rope.

Figure 3 is a front view of Fig.1 with the cover plate removed and with the primary braking mechanism in a second operative position

Figure 4 is a front view of Fig.1 with the cover plate removed and with the primary braking mechanism in a third operative position and the secondary braking mechanism in a second operative position.

Figure 5 is a front view of Fig. 1 with the cover plate removed and the rope in the low friction position.

Figure 6 is a front view of Fig 1. With the cover plate moved to its rope loading/unloading position.

A preferred embodiment of the invention comprises a predominantly circular pulley 1 mounted eccentrically with relation to its centre on a spindle 3 secured normally on a flat portion of a first supporting plate 5. A second supporting plate 6 or cover plate is mounted parallel to the first supporting plate 5, the second supporting plate 6 being pivotally movable between a rope loading/unloading position and a closed position to allow rope 7 to be inserted and then retained in the device. The outer circumferential surface of the first pulley 1 is provided with a groove to retain the rope around the circumferential surface of the pulley.

An aperture 8 corresponds with a similar aperture 9 in the second supporting plate 6 to allow a connector, such as a karabiner or screw link, to be inserted to connect the device to a person or a secure anchorage point. A first abutment member 10 is mounted normally on the first supporting plate 5 adjacent to the pulley 1. A second abutment member 11 is mounted on the first supporting plate 5 between the pulley 1 and the first bollard 2. A first and second bollard 2,18 are mounted normally on the first supporting plate 5 such that they define between them a substantially s-shaped rope path with the rope 7 passing around pulley 1 , between pulley 1 and abutment member 10, around first bollard 2 then around second bollard 18. In an alternative arrangement the rope 7 only passes around the pulley 1 and past second abutment member 11.

A control handle 12 comprising an elongate flat plate is secured to the first pulley 1 parallel to and adjacent to the first supporting plate 5. A third abutment member or bollard 13 is mounted on the control handle 12, normally to the control handle 12 so that the rope 7 leaving the pulley 1 passes between the bollard 13 and the abutment member 11.

The first pulley 1 , the first bollard 10 and control handle 12 together constitue a primary braking mechanism, while the bollard 13 and abutment means 11 constitute a second braking system.

In use the second supporting plate 6 is moved to its rope loading/unloading position and a rope 7 is threaded anti-clockwise in a U-shape around the pulley 1 , moving away from the downstream end 14 of the rope 7 (i.e. the end of the rope to which the load is to be applied). The rope 7 is then passed between the pulley 1 and the first bollard 10. Next the rope 7 passes between the abutment means 11 and bollard 13, it is then threaded clockwise around the bollard 2 to describe an S-shape before passing the around the bollard 18 and leaving the device.

When a load is applied to a downstream end 14 of the rope 7, the frictional force created by the rope 7 around the pulley 1 will cause the pulley 1 of the primary braking mechanism to pivot in a clockwise direction, thus locking rope 7 securely between point surfaces on the pulley 1 and first bollard 10.

In order to release the rope 7 the control handle 12 is pressed towards the first and second supporting plates 5,6, moving the pulley in an anti clockwise direction. Once the control handle 12 has been pressed to release the rope 7 the rope can move through the device, with additional friction provided by bollards 2 and 18.

During the release of the primary braking mechanism, further movement of the control handle towards the first and second plates 5,6 moves the bollard 13 towards the abutment means 11 clamping the rope securely therebetween. Thus, the bollard 13 will allow the device to brake the rope to a complete halt if the control handle is operated in panic.

The second plate 6 contains a cut out 17 so that the free end of the rope 15 may be threaded around or removed from bollards 2 and 18 whilst the second plate 6 is in the closed position and if required, whilst either the primary or secondary braking mechanisms are in operation. This alternative threading arrangement provides a low friction position which allows the user to take in slack rope by pulling the free end of the rope 15, or, to pay out rope by operating the control handle 12, without the additional friction form bollards 2 and 18. In an alternative embodiment the abutment means may take the form of a cleat to allow large loads to be held by the secondary braking mechanism without large forces being applied to the control handle 12.

Claims

1. A descender for controlling the lowering and/or raising of a load on a rope, the descender comprising rope guide means for guiding and controlling the passage of a rope through the descender and attachment means for attaching the descender to a further rope and/or an object/person to be lowered and/or raised, the rope guide means includes locking means comprising a first locking member moveable between a rope jamming position wherein the rope is trapped between the locking member and an adjacent abutment and a release position wherein the locking member is spaced from said abutment, the rope guide means being arranged such that the first locking member is urged towards its rope jamming position when a load is applied to a downstream end of the rope, the first locking member being selectively moveable towards its release position in order to selectively control the movement of the rope through the rope guide means, wherein the rope can be mounted in the rope guide means in two operative configurations, a first configuration for controlled lowering/raising a load and a second configuration wherein the rope can move through the rope guide means with less resistance to movement than when in the first configuration for easing the passage of rope through the descender when the rope is under light tension to assist adjustment of slack or when paying out rope under light tension, wherein the rope can be moved between its first and second operative configurations without removing the rope from the locking means.

2. A device as claimed in claim 1 , wherein the locking means comprises a second locking member, the second locking member being mounted on and/or actuated by said control lever and being co-operable with a second abutment, the second locking member being moveable between a rope jamming position wherein the rope is trapped between the second locking member and the second abutment and a release position wherein the second locking member is spaced from said second abutment.

3. A device as claimed in claim 2, wherein the second locking member comprises a substantially cylindrical peg extending perpendicularly from the control handle.

4. A device as claimed in claim 2, wherein the second abutment comprises a substantially rectangular peg extending perpendicularly from the first supporting plate.

5. A device as claimed in claim 2, wherein the second abutment takes the form of a cleat to assist in holding large loads without large forces being applied to the handle.

6. A device as claimed in any preceding claim, wherein the second mounting plate is shaped to allow the rope to be moved between its first and second operative configurations while the second mounting plate is in its closed position.

7. A device as claimed in any preceding claim, wherein the control lever has three operative positions, a first position wherein the rope is trapped between the first locking member and its adjacent abutment and the second locking member is spaced from the second abutment, a second, intermediate, position wherein both the first and second locking members are spaced from their respective abutments to permit passage of the rope through the rope guide means, and a third position wherein the rope is trapped between the second locking member and the second abutment and the first locking member is spaced from its adjacent abutment.

8. A device as claimed in claim 8, wherein the control lever comprises an elongate substantially flat plate parallel to and adjacent the first and second supporting plates.

9. A device as claimed in any preceding claim, wherein the rope guide means comprises a pulley and a bollard, the rope passing around the pulley and between the pulley and the bollard only when the rope is in its first configuration. Preferably the pulley is non-rotatable whereby the rope must slide around the pulley when the rope is in its first configuration.

10. A device as claimed in any preceding claim, wherein the second mounting plate is movable between a rope loading/removing position and a closed position wherein the second mounting plate covers at least the gap between the first locking member and its adjacent abutment to retain the rope within the device.

11. A device as claimed in any preceding claim, wherein the second bollard contains a groove substantially parallel to the first mounting plate in order to keep the rope in place around the bollard.

12. A device as claimed in any preceding claim, wherein the first locking member comprising a first cam or eccentric pulley pivotably mounted on the first mounting plate for rotation about a rotational axis normal to said first mounting plate between its rope jamming position and its release position, said adjacent abutment being mounted on and extending from said first backing plate.

13. A device as claimed in any preceding claim, wherein the attachment means comprises a first aperture provided adjacent one end of the first mounting plate and a second aperture provided adjacent one end of the second mounting plate, said first and second apertures being aligned with one another when the second mounting plate is in the closed position to allow a connector, such as a karabiner or screw link to be inserted through both apertures to connect the device to a person or secure anchorage point.

14. A device substantially as herein described with reference to the accompanying drawings.