GB2515341A

GB2515341A - Rope safety device

Info

Publication number: GB2515341A
Application number: GB1311100.0A
Authority: GB
Inventors: Keith Jones; Christopher Mark Edmondson
Original assignee: HIGHTEC GROUP Ltd
Current assignee: HIGHTEC GROUP Ltd
Priority date: 2013-06-21
Filing date: 2013-06-21
Publication date: 2014-12-24
Anticipated expiration: 2033-06-21
Also published as: GB2515341B; GB2543699A; GB201311100D0; GB201702088D0; GB2543699B

Abstract

A rope safety connector is a body 1,10 having an attachment aperture (internal eye) 2,12 for connecting the device body to an anchor point or harness. The body has a plastically deformable portion adjacent the aperture which is adapted to deform when the load applied to the attachment aperture exceeds a predetermined minimum. The body may be made from a single material with one or more slots 3, 4 (which may be concentrically arranged) or a reduced thickness creating the deformable region; or it may include a region of more deformable material 15, a rolled up strip or a helical spring. Movement of the aperture is directed and restricted by a guide opening 11 in the body of the connector. The device is to reduce shock loading in the event of a fall arrest.

Description

Rope Safety Device This invention relates to a rope safety device for arresting the descent of a person or other load down a rope, lifeline, cable, web or other similar elongate load supporting member or line (collectively referred to hereinafter as" rope"), and in particular to a fall arrest device for arresting the descent of a person down a rope in the event of a fall.

Rope safety devices for fall protection and rescue are known, such devices operating on a rope, cord tape, web, rail or other elongate load supporting member (collectively referred to hereinafter as rope) and commonly incorporating an aperture for the attachment of a Karabiner or similar connector to connect the device to an anchor point or the user's harness.

Such attachment aperture may be formed in the body of the device or may comprise an external eye' securedly affixed to the device. Some known devices include an external eye with a shear pin or similar such that the pin will fail when the load exceeds a certain threshold, allowing the attachment between the device and the eye to extend. This indicates if the device has been subject to a load but the extension of the attachment imparts a shock load to the device. Such eyes are also expensive and, being external to the device, increase its outside dimensions. Such indicators are advantageous as they clearly show if a device has been used under load, however they are currently so complicated that they are only fitted to large expensive items. Any shock load imparted to the device can have a detrimental effect. In addition, such indicators are not incremental and do not show that the load is increasing.

Shock absorbers which dampen the impact are common but these are large and, typically being textile, prone to damage. Deforrnable metal shock absorbers are known, but these are currently only used on devices which operate on a fixed rail.

The rail, being fixed, prevents the device from moving during deployment ensuring that the metal absorber deploys correctly. If used in a system containing flexible rope the direction of deployment is not controlled and can as such vary and change the loading on the device itself. Such absorbers must by definition, have a low strength so that they can deform. Following deployment, this low tensile strength leaves a weak link in the system.

According to a first aspect of the present invention there is provided a rope safety device comprising a body having an attachment aperture for connecting the device to an anchor point or harness, said body incorporating a plastically deformable portion associated with said attachment aperture whereby said plastically deformable portion is adapted to deform when the load applied to the attachment aperture exceeds a predetermined minimum.

In one embodiment, said plastically deformable portion comprises a region of said body extending between said attachment aperture and one or more further apertures or slots formed in said body adjacent said attachment aperture.

Said one or more further apertures or slots may be arranged concentrically with said attachment aperture.

In an alternative embodiment said plastically deformable portion comprises a region of the body formed from a different material from the remainder of the body and/or comprising a region of the body of reduced thickness relative to the remainder of the body.

Preferably said plastically deformable portion is mounted within a guide opening formed in the body of the device for guiding and limiting the deformation of said plastically deformable portion. Preferably said attachment aperture is formed within said plastically deformable portion.

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which Figure 1 is a side view of a rope safety device in accordance with a first embodiment of the present invention, before deformation; Figure 2 is a side view of the rope safety device of Figure 1, after deformation; Figure 3 is a side view of a rope safety device in accordance with a second embodiment of the present invention, before deformation; and Figure 4 is a side view of the rope safety device of Figure 3, after deformation.

As shown in Figures 1 and 2, a rope safety device according to a first embodiment of the present invention comprises a body 1 supporting a device (not shown) for engaging a rope, the body 1 incorporating at least one attachment aperture 2.

Two concentric slots 3,4 are formed in the body in close proximity to the attachment aperture 2, arranged concentrically therewith. The regions of the body 1 between the attachment aperture 2 and slot 3,4 are plastically deformable whereby such regions will progressively deform when the load applied to the device via aperture 2 exceeds a predetermined threshold in the direction of said slots 3,4, such deformation serving to close slots 3,4, indicating visually that the load has exceeded the predetermined threshold and at the same time absorbing energy from a fall or impact. If the deformation reaches a point where said slots 3,4 are fully closed, a connector affixed to the attachment aperture 2 is in direct operative contact with the body 2 and further deformation is prevented. At this stage, further deformation cannot take place and thus there is no risk of failure of the connection aperture.

This is an improvement over prior art attempts to provide deformable features associated with an attachment apertures, which tend to reduce the ultimate strength of the attachment by failing to delimit the deformation of the deformable feature.

The number of slots and/or the shape and/or the dimensions of the slots and/or spacing of the slots and/or the type of material between the attachment aperture 2 and the slots 3,4 may be varied such that the load at which deformation occurs may be increased or decreased as required and to allow the distance over which deformation occurs and as such the amount of energy absorption to be varied.

Furthermore, the position and/or orientation of slots and the amount they extend around attachment aperture 2 may be varied so that the direction of deformation may be varied as required.

In an alternative embodiment of the invention, shown in Figures 3 and 4, body 10 incorporates a guide opening 11, within which is mounted a section of plastically deformable material 15. An attachment aperture 12 is formed in this section of plastically deformable material for receiving a connector. When a load is applied to the device via the attachment aperture 12 exceeds a predetermined threshold, the plastically deformable section 15 begins to progressively deform, indicating visually that the load has exceeded the predetermined threshold and at the same time absorbing energy from a fall or impact. This deformation reaches a maximum when the attachment aperture 12 reaches an end region of the guide opening 11, as shown in Figure 4, wherein a connector affixed to the attachment aperture 12 is in direct operative contact with the body 10 and further deformation is prevented. Thus the ultimate strength of the attachment aperture 12 is not compromised. The size and orientation of said guide opening 11 may be varied such that the direction and amount of deformation may be predetermined.

In a further alternative embodiment, not shown, the body may comprise a support plate containing at least two attachment apertures, at least one of said apertures being associated with a plastically deformable portion as described in either of the first two embodiments. Such support plate may be capable of being attached to a rope safety device, harness or similar via at least one attachment aperture.

The invention is not limited to the embodiment(s) described herein but can be amended or modified without departing from the scope of the present invention. For example, the plastically deformable region may comprise a separate piece pivotally mounted on device. The plastically deformable region may comprise a rolled up strip which uncoils or a helical spring shape which stretches. However, in both cases, the amount of deformation will be limited by the provision of a guide opening or similar means for delimiting the path and magnitude of deformation of the plastically deformable region.

Claims

Claims 1. A rope safety device comprising a body having an attachment aperture for connecting the device to an anchor point or harness, said body incorporating a plastically deformable portion associated with said attachment aperture whereby said plastically deformable portion is adapted to deform when the load applied to the attachment aperture exceeds a predetermined minimum.
2. A device as claimed in claim 1, wherein said plastically deformable portion comprises a region of said body extending between said attachment aperture and one or more further apertures or slots formed in said body adjacent said attachment aperture.
3. A device as claimed in claim 2, wherein said one or more further apertures or slots are arranged concentrically with said attachment aperture to facilitate progressive deformation of said plastically deformable portion in a controlled direction.
4. A device as claimed in claim 1, wherein said plastically deformable portion comprises a region of the body formed from a different material from the remainder of the body and/or wherein said plastically deformable region comprises a region of the body of reduced thickness relative to the remainder of the body.
5. A device as claimed in claim 4, wherein said plastically deformable portion is mounted within a guide opening formed in the body of the device for guiding and limiting the deformation of said plastically deformable portion.
6. A device as claimed in claim 4 or claim 5, wherein said attachment aperture is formed within said plastically deformable portion.
7. A rope safety device substantially as herein described with reference to the accompanying drawings.