Descending device

Abstract

A descent device is provided that includes a body for attachment to a load, such as a person, and a series of apertures extending through the body for passage of a cord in alternating directions from a first aperture to a final aperture such that areas of the body defining the apertures and extending between the apertures provide discontinuous contact surfaces for frictional engagement with the cord. The series of apertures includes a first set of apertures providing a first frictional resistance and including a first aperture and a second set of apertures providing a second frictional resistance greater than the first frictional resistance and including a final aperture. The device can be used as an emergency descent device, such as allowing a person to descend from one location to another to escape from a hazardous environment.

Description

Technical Field

[0001] The present invention relates to a descent device. In particular, but not exclusively, the present invention relates to a descent device for use in emergency situations, such as allowing a person to descend from one location to another to escape a dangerous environment. Background Art

[0002] A descending device (sometimes referred to as a descender device or a descent device) may be used as part of a descent system, including a descent rope and other equipment (such as a safety harness and anchor) to allow a person to be descended from one location to another. There are different types of descending devices, and different types of descending devices are intended for different purposes, including recreational use and for use in emergency situations. For emergency situations, a descending device may be used, for example, to permit a person to quickly escape from a hazardous environment on an upper floor of a building or other elevated location, including offshore oil and gas platforms, floating production storage and offloading (FPSO) units, drilling rigs, and vessels.

[0003] Descending devices may be automatic (type 1 as defined in European standard EN 341:2011) or manually operated (type 2 as defined in EN 341:2011). Automatic descending devices are intended for use when the user does not need to control the speed of descent, and therefore the speed of descent is automatically controlled, i.e. without user intervention. Manual descending devices are used when the user may need to control the speed of descent (including the need to stop at a certain position along the descent rope). However, manual descending devices (particularly those used in emergency situations) may have at least some degree of automatic control to allow them to be used safely without user intervention.

[0004] Figure 1 A descent system 10 is shown which is disclosed in an earlier patent application WO 90 / 04998. The system 10 comprises a harness 12 attached to a descent device 14 (a restrainer member) through which a rope 16 of sufficient length can be passed at a controlled rate to enable a user to be descended from one position to another. The descent device 14 is in the form of a disc-shaped plate defining a series of parallel elongated slots through which the rope 16 is passed alternately in opposite directions. The descent device 14 comprises a large hole 20 which can be used as a handle and which increases in thickness near the base of the device 14 to provide a further hole to receive the shaft of a quick release carabiner 24. The rope 16 is stored in and released from a bag 26 and has a securing hook 28 at its free end.

[0005] When it is desired to use the system 10, the hook 28 is secured to a fixed point. The user puts on the harness 12 and can pull the rope 16 through the descending device 14 to provide enough free space for the rope 16 above the device 14 for the user to put on the harness 12. Once freely hanging on the device 14, the user can control the rate of descent by paying out the rope 16 from the bag 26, or simply allowing the rope to be paid out at a controlled rate determined by the bag 26. At any time, the descent can be slowed by the user holding the lower section of the rope 16 (i.e., the section of the rope 16 that has not yet entered the device 14). If it is necessary to stop the descent and lock the device 14 to prevent further descent, the user can wrap the lower section of the rope 16 around the device 14 so that the lower section of the rope 16 is trapped between the device 14 and the upper section of the rope 16 (i.e., the section of the rope 16 that has left the device 14).

[0006] It is desirable to provide a descending device capable of maintaining a continuous descent at a desired maximum descent speed, such as 2 m / s (as required by EN 341:2011), in particular a manually operated descending device capable of maintaining a continuous descent speed without user intervention. Furthermore, it is desirable to provide a descending device capable of maintaining a desired descent speed for a range of loads and / or under a range of conditions, such as wet / dry conditions and hot / cold conditions.

[0007] It is an object of embodiments of the present invention to provide an improved descent apparatus, for example capable of maintaining a continuous descent speed as described above, and / or to at least alleviate one or more problems associated with known arrangements. Summary of the invention

[0008] According to one aspect of the present invention, there is provided a descending device, comprising: a body for attachment to a load; and a series of holes extending through the body, the series of holes for a rope to pass through from a first hole to a final hole along an alternating direction, so that the defining holes of the body and the area extending between the holes provide a discontinuous contact surface for frictional engagement with the rope, wherein the series of holes includes a first group of holes providing a first friction resistance and including the first hole and a second group of holes providing a second friction resistance greater than the first friction resistance and including the final hole. Typically, the first group of holes can provide a basic amount of friction resistance and is primarily used as a guide, while the second group of holes can provide a relatively higher amount of friction resistance depending on the load and is primarily used as a brake. The device can be used in emergency situations, such as allowing a person to descend from one location to another to escape a dangerous environment. In particular, the device can be operated without user intervention, allowing a person to descend from one location to another at a controlled descent speed under a range of loads.

[0009] In some embodiments, the first group of holes may include one or more holes with a first height, which is less than the height of one or more of the remaining holes in the first group of holes. One or more holes with a first height may include the first hole, and in some embodiments may only include the first hole. Additionally or alternatively, the second group of holes may include one or more holes with a second height, which is less than the height of one or more of the remaining holes in the second group of holes (the height of one or more of the remaining holes in the second group of holes may be the same or different from the height of one or more of the remaining holes in the first group of holes). One or more holes with a second height may include the final hole and one other hole, and in some embodiments may only include the final hole and one other hole. The first height may be equal to the second height, and / or each hole in a series of holes may have a height other than the first height or the second height, with a third height. The body may be substantially planar.

[0010] In some embodiments, the first group of holes can be spaced apart from each other by a first spacing, and the second group of holes can be spaced apart from each other by a second spacing, the second spacing being greater than the first spacing. The first group of holes and the second group of holes can be spaced apart from each other by the first spacing. Additionally or alternatively, the series of elongated holes can include five holes, the first group of holes includes three holes, and the second group of holes includes two holes. In some embodiments, the series of elongated holes can consist of six holes, the first group of holes consists of three holes, and the second group of holes consists of three holes.

[0011] In some embodiments, one or more of the holes may include a rounded or chamfered edge extending around its perimeter on a first side of the body and / or on a second side opposite the body. The holes in the series of holes may be a series of parallel elongated slots. One or more of the slots in the series of parallel elongated slots may have a first width.

[0012] In some embodiments, the device includes a rope that passes through a series of holes in an alternating direction (i.e., from a first hole to a final hole). The rope can have a thickness that is at least 50% of the first height and / or the second height. The rope can have a width that is approximately equal to the first width. The rope can include a certain length of braided flat belt or braided tubular belt.

[0013] In some embodiments, the first height and / or the second height can be approximately 4 mm (e.g., 4 mm + / - 0.5 mm), and the thickness of the rope is approximately 2 mm (e.g., 2 mm + / - 0.5 mm). Additionally or alternatively, the first spacing can be approximately 9 mm (e.g., 9 mm + / - 2 mm), and the second spacing can be approximately 11 mm (e.g., 11 mm + / - 2 mm).

[0014] In some embodiments, the device may include further holes extending through the body to attach a load thereto (i.e., connection holes), including holes for connecting a quick release carabiner or the like to the body. Additionally or alternatively, the device may include further holes extending through the body to provide a handle (i.e., handle holes). BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0016] Figure 1 is a perspective view of a descent system according to the prior art, which includes a descent device according to the prior art;

[0017] Figure 2 is a front view of a descending device according to an embodiment of the present invention, the device comprising a first set of holes and a second set of holes;

[0018] Figure 3 It is cut through the center of the hole Figure 2 A cross-sectional view of the descending device; and

[0019] Figure 4 yes Figure 2 An enlarged partial view of the descending device showing the height of the holes and the spacing between the holes. DETAILED DESCRIPTION

[0020] Embodiments of the present invention may be applied as automatically or manually controlled descending devices, and may be particularly applied in emergency situations to allow a person to descend from one location to another to escape a dangerous environment. Embodiments of the present invention may be controlled by a user or a third party to lower a user (e.g., a wounded person) or other load in a controlled manner. However, embodiments of the present invention may also be operated without user or third party intervention, protecting users who may be injured or unconscious and therefore unable to control the speed of descent, minimizing the possibility of further injury due to impacting the ground or other surfaces at an uncontrolled speed.

[0021] Embodiments of the present invention may be disposable and / or may be simple and inexpensive to manufacture. Embodiments of the present invention may replace Figure 1 The descent device 14 or the descent device 14 and the rope 16 in the prior art arrangement of the present invention. Therefore, the embodiments of the present invention can be used for use in new descent systems and / or for retrofitting existing descent systems.

[0022] Figure 2 , Figure 3 and Figure 4A descent device 100 is shown according to an embodiment of the present invention. The device 100 comprises a substantially planar, disc-shaped body 101 having a first side 102 and an opposing second side 103, and the device further comprises a series of holes 104 extending through the body 101. In the illustrated embodiment, the holes 104 are provided as a series of parallel elongated slots. The holes 104 are arranged from a first hole 105 to a final hole 106 so that a descent rope can pass through the body 101 in alternating directions, the rope first entering the body 101 by passing through the first hole 105 and finally leaving the body 101 by passing through the final hole 106. When the rope passes through the holes 104, the rope contacts areas of the body 101 that define the holes 104 and extend between the holes. These areas provide the body 101 with discontinuous contact surfaces that frictionally engage with the rope.

[0023] As will be appreciated by those skilled in the art, the above-described frictional engagement of the body 101 and the rope will produce frictional resistance that slows the rope's passage through the body 101 (i.e., through the hole 104) and thereby determines the rate of descent of the device 100 for a given load. The frictional resistance is calculated by multiplying the normal force by the coefficient of friction (the greater the total normal force, the greater the friction). Thus, the total frictional resistance exhibited by the device 100 is proportional to the sum of the angles at which the rope bends as it passes through the body 101.

[0024] The series of holes 104 includes a first set of holes 107 and a second set of holes 108. The first set of holes 107 are arranged so that the rope passes through each hole in succession and are configured to collectively provide a first frictional resistance to slow the rope passing through the body 101. Similarly, the second set of holes 108 are arranged so that the rope passes through each hole in succession and are configured to collectively provide a second frictional resistance to slow the rope passing through the body 101. In use, the rope first passes through the first set 107 and then through the second set 108.

[0025] It has been found that by making the second frictional resistance greater than the first frictional resistance, the device 100 can exhibit improved descent control. In particular, the device 100 can maintain continuous descent at a desired maximum descent speed under a range of loads, including a descent speed of no more than 2m / s under a load range of from 50kg to 150kg. The frictional resistance of each group 107, 108 can be changed by adjusting the height of one or more holes. As used herein, the height of the hole is a dimension parallel to the overall direction of the rope passing through the body 101. Reducing the height of the hole increases the clearance of the rope when it passes through the hole, which increases the normal force acting on the contact surface and causes an increase in frictional resistance.

[0026] In the illustrated embodiment, the first group of holes 107 includes three holes: a first hole 105, a second hole 109, and a third hole 110. The second group of holes 108 also includes three holes: a fourth hole 111, a fifth hole 112, and a final hole 106. The first group 107 includes a single hole (e.g., the first hole 105) having a first height H1, which is less than the height of the remaining holes of the first group 107. The second group of holes 108 includes two holes (e.g., the fourth hole 111 and the final hole 106) having a second height H2, which is less than the height of the remaining holes of the second group 108. The first height H1 and the second height H2 are equal to each other, and the height of the remaining holes of the first group 107 and the second group 108 is a third height H3.

[0027] As a result of the above arrangement, the sum of the normal forces generated by the rope passing through the second set of holes 108 is greater than the sum of the normal forces generated by the rope passing through the first set of holes 107. Therefore, the second set 108 is responsible for most of the frictional resistance exhibited by the device 100, and crucially, the magnitude of the frictional resistance of the second set 108 is more variable with changes in load, i.e. the second set 108 is more sensitive to changes in the load applied to the device in use than the first set 107. Thus, the first set 107 provides a relatively low base level of frictional resistance and acts primarily as a guide for stabilizing and feeding the rope to the second set 108, which provides a relatively high frictional resistance depending on the load and acts primarily as a brake.

[0028] Although the first hole 105 has a first height H1, the contribution of the first hole to the frictional resistance is not necessarily as great as each of the fourth hole 111 and the final hole 106, each of which has a second height H2 that is the same as the first height H1, because the rope will be subjected to less tension when the rope enters the first hole 105. The height of the first hole 105 can be smaller than the heights of the remaining holes of the first group 107 to provide improved descent control by the user holding the rope before the rope enters the body 101, that is, to make the first hole 105 more sensitive to changes in the angle at which the user holds the rope relative to the body 101.

[0029] It has also been found that the frictional resistance of each group 107, 108 can be varied by adjusting the spacing between adjacent holes, particularly when the rope is provided in the form of a braided tubular webbing. In the illustrated embodiment, the first group of holes 107 are spaced apart from each other by a first spacing S1, and the second group of holes 108 are spaced apart from each other by a second spacing S2. In addition, the first group of holes 107 and the second group of holes 108 (i.e., the third hole 110 and the fourth hole 111) are spaced apart from each other by a first spacing S1. The second spacing S2 is greater than the first spacing S1, thereby increasing the frictional resistance of the second group 108 relative to the first group 107.

[0030] While any suitable hole configuration may be used, the series of holes 104 of the illustrated embodiment has been found to be particularly suitable. The first height H1 and the second height H2 may be approximately 4 mm, and the third height H3 may be approximately 6 mm. The first spacing S1 may be approximately 9 mm, and the second spacing S2 may be approximately 11 mm. The thickness of the body 101 may be approximately 12 mm. Each of the series of holes 104 may include a rounded or chamfered edge 113 extending around its perimeter on each of the first side 102 and the second side 103, including a rounded edge having a radius of approximately 3 mm. Each of the series of holes 104 may have a width W1 of approximately 18 mm.

[0031] Similarly, any suitable rope may be used, although rope having a thickness of approximately 50% of the first height H1 and the second height H2, for example approximately 2 mm thick, has been found to be particularly suitable. The width of the rope may be substantially equal to the width W1 of the aperture 104, or at least within 2 mm thereof.

[0032] For the body 101, a lightweight metal alloy, such as an aluminum alloy, is preferred. However, the body 101 may be made of a rigid plastic material with a metal insert around the hole 104 to facilitate the dissipation of heat generated by frictional engagement with the rope and to prevent excessive wear. The rope may be provided in the form of a braided belt, including a braided tubular belt and a braided flat belt, and may be made of any suitable material. Particularly suitable materials for the rope include nylon and polyester fibers.

[0033] The descending device 100 can be used in a descending system (such as Figure 1 The descent system 10 is used in the embodiment shown.

[0034] The present invention is not limited to the details of any of the foregoing embodiments. For example, although in the illustrated embodiment, the holes 104 are provided as a series of parallel elongated slots, holes of other shapes, including circular or square holes, are also conceivable. The exact number, spacing, size and shape of the holes 104 can be determined according to the specific application. The size and shape of the body 101 can be any suitable size and shape, so the first height H1 does not need to be equal to the second height H2. The device 100 may further include additional features, such as another hole 114 providing a handle for the user to hold and another hole 115 for connecting to a hook or the like (i.e., a device for attaching a load to the body 101). As shown in the illustrated embodiment, the hole 104 can be offset from the centerline of the device, or can be aligned with the centerline and / or another hole 115 for attaching a load to the body 101.

[0035] Throughout the description and claims of this specification, the words "comprise" and "comprising" and their variations mean "including but not limited to", and they are not intended to (and do not) exclude other components, additives, parts, integral structures or steps. Throughout the description and claims of this specification, the singular encompasses the plural, unless the context requires otherwise. In particular, where the indefinite article is used, the specification should be understood to contemplate the plural as well as the singular, unless the context requires otherwise.

[0036] Features, overall structures or characteristics described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All features disclosed in this specification (including any accompanying claims, abstract and drawings) and / or all steps of any method or process so disclosed may be combined in any combination, except for at least some mutually exclusive combinations of such features and / or steps. The invention extends to any novel feature or any novel combination of features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel step or any novel combination of steps of any method or process so disclosed.

[0037] Attention is paid to all papers and documents filed concurrently with or prior to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

Claims

1. A descending device, comprising: a body for attachment to a load; and a series of holes extending through the body through which the cord passes in alternating directions from a first hole to a final hole so that areas of the body defining the holes and extending between the holes provide a discontinuous contact surface for frictional engagement with the cord, The series of holes includes a first group of holes providing a first frictional resistance and including the first hole and a second group of holes providing a second frictional resistance greater than the first frictional resistance and including the final hole.

2. The descending device according to claim 1, wherein: The first set of holes includes one or more holes having a first height that is less than a height of one or more of the remaining holes of the first set of holes.

3. The descending device according to claim 2, wherein: The one or more holes having a first height include the first hole.

4. A descending device according to claim 1, 2 or 3, wherein: The second set of holes includes one or more holes having a second height that is less than a height of one or more of the remaining holes of the second set of holes.

5. The descending device according to claim 4, wherein: The one or more holes having a second height include the final hole and one other hole.

6. A descending device according to claim 4 or 5 as appended to claim 2 or 3, wherein: The first height is equal to the second height.

7. The descending device according to any one of claims 2 to 6, wherein: Each hole in the series of holes having a height other than the first height or the second height has a third height.

8. A descent device according to any preceding claim, wherein: The first set of holes are spaced apart from each other by a first spacing, and the second set of holes are spaced apart from each other by a second spacing, the second spacing being greater than the first spacing.

9. The descending device according to claim 8, wherein: The first group of holes and the second group of holes are spaced apart from each other by the first spacing.

10. A descent device according to any preceding claim, wherein: The series of elongated holes includes five holes, the first set of holes includes three holes, and the second set of holes includes two holes.

11. A descent device according to any preceding claim, wherein: The series of elongated holes consists of six holes, the first group of holes consists of three holes, and the second group of holes consists of three holes.

12. A descent device according to any preceding claim, wherein: One or more of the apertures includes a rounded or chamfered edge extending around its perimeter on a first side of the body and / or on an opposing second side of the body.

13. A descent device according to any preceding claim, wherein: The holes in the series of holes are a series of parallel elongated slots.

14. The descending device according to claim 13, wherein: One or more slots in the series of parallel elongated slots have a first width.

15. A descent device according to any preceding claim, wherein: The device includes a cord that passes through the series of holes in alternating directions.

16. A descending device according to claim 15 as appended to at least claim 2 or 4, wherein: The rope has a thickness of at least 50% of the first height and / or the second height.

17. A descending device according to claim 15 or 16 as at least dependent on claim 14, wherein: The rope has a width approximately equal to the first width.

18. A descending device according to claim 15, 16 or 17, wherein: The rope comprises a length of braided flat webbing or braided tubular webbing.

19. A descending device according to any one of claims 15 to 18 as dependent at least on claim 2 or 4, wherein: The first height and / or the second height is approximately 4 mm, and the thickness of the rope is approximately 2 mm.

20. A descending device according to claim 8 or at least any one of claims 9 to 19 as dependent thereon, wherein: The first spacing is approximately 9 mm and the second spacing is approximately 11 mm.

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