This invention relates to personal protective equipment and, more particularly, harnesses or components thereof. Particularly, but not exclusively, the invention relates to components used to make a harness suitable for use in supporting a person working at height using rope access and hardware (metal components) that are used within its construction. It also has application for a harness and hardware that are part of a fall-protection system, for example for use by a climber.
A harness may be designed to support a user when working at height, to provide a comfortable body support for performing tasks when suspended from a rope access system. Alternatively or additionally, a harness may be used to arrest a user's fall, for example in a fall protection system used by a climber where there is the potential for a fall. Embodiments of the invention might find application to hardware used for rope access, industrial height safety, rescue, tactical applications, sport climbing, etc. Within this specification, example embodiments will be described that relate to harnesses intended for use in tree care, but this should not be taken to be limiting upon the range of applications of the invention.
This application relates to the components of a harness assembly which is of the general construction shown in
A known harness is shown in
Each side wing has a side attachment arrangement 20, shown in more detail in
Existing products and designs typically use a multitude of components to create a side attachment assembly. Not only does this produce a side attachment arrangement that is difficult to build into a harness at the manufacturing stage, it also gives limited opportunity following manufacture to replace textile elements, which are susceptible to wear through abrasion or other damage such as cuts, heat damage, and so forth. This can lead to users making their own solutions for repairing a worn side attachment assembly, which is undesirable because the effectiveness of such a repair cannot be guaranteed, or the harness being retired from service while many of its components are still well within their working lives.
Existing harnesses use a pair of symmetric forward attachment arrangements 27 as shown in
An aim of this invention is to provide a harness that that overcomes or at least ameliorates these disadvantages.
To this end, from a first aspect, the present invention provides a harness for supporting a person working at height comprising a back, leg loops, two forward connection arrangements and a flexible load-bearing member that extends between the connection arrangements, the forward connection arrangements serving to transferring load from the back and the leg loops to the load-bearing member, in which each forward connection arrangement comprises: a body that is permanently connected to the harness and a retention component that can be removably and typically rigidly connected to the body to removably secure the flexible load-bearing member to the body, and thence to the other components of the harness.
Replacement of the flexible load-bearing member can be achieved by removal of the retention components during servicing of the harness. Suitable formations for connection to the retention components, such as sewn loops, can be provided in the flexible load-bearing member during its manufacture, thereby avoiding the need to form them later, as is the case of a conventional flexible load-bearing member, which has to be securely knotted after it has been installed in the forward connection arrangement.
In embodiments of the invention, the flexible load-bearing member may include a loop and the retention components include a bar that when separate from the body can pass through the loop, and that, when connected to the body, is secured within the loop. The bar is typically secured to the body by bolts and nuts.
In such embodiments, the loop may be formed to include a region which will fail upon application of a force above a threshold but below a maximum working force to cause the effective length of the flexible load-bearing member to increase. This can limit the force that is applied to a user when the harness is acting to arrest a fall.
As an alternative to a bar, the retention component may include a knot blocker. That is, a component with a through hole through which a length of rope can pass, but which prevents the passage of a knotted rope. This can provide a more versatile form of attachment, allowing a user to adjust the length of the bridge by varying the position of a knot upon it.
To provide flexibility in operation, the retention components include an adjuster (e.g., a rope adjuster) that can be caused to grip the flexible load-bearing member at one of a range of positions. Typically, the adjuster allows the effective length of the flexible load-bearing member to decrease by application of a tensile force to a free end of the flexible load-bearing member. The adjuster may allow the effective length of the flexible load-bearing member to increase upon manual intervention by a user prior to application of a tensile force to the flexible load-bearing member.
The secured flexible connecting member passes through the body. This can ensure that the connection between the flexible load-bearing member and the body is not immediately lost in the event that the retention components become detached from the body, for example, as a result of a fastener becoming loose.
A harness embodying the invention may have two similar forward connection arrangements. Alternatively, it may have two dissimilar forward connection arrangements, for example, one having a loop and retention bar arrangement and the other having a rope adjuster arrangement as discussed above.
A harness embodying the invention may have one, two or more flexible connecting members each of which is removably secured to the harness by the or each forward connection arrangement. Typically, the body of each forward connection arrangement is permanently connected to a waist webbing that extends about the back of the harness and the body of each forward connection arrangement is permanently connected to a respective riser that is connected to a respective leg loop.
From a second aspect, the present invention provides a harness for supporting a person working at height comprising a back, leg loops, two forward connection arrangements and a flexible load-bearing member that extends between the connection arrangements, the forward connection arrangements serving to transferring load from the back and the leg loops to the load-bearing member, in which flexible load-bearing member includes an energy dissipation region which will fail upon application of a force above a threshold but below a maximum working force to cause the effective length of the flexible load-bearing member to increase.
The energy dissipation region may include a region that will fail progressively upon the load in the flexible load-bearing member being in excess of the threshold. For example, the energy dissipation region may include stitching that will progressively fail when the load in the flexible load-bearing member being in excess of the threshold.
Optional features of the invention from its first aspect may also be present in embodiments of the invention form its second aspect.
In the drawings:
Embodiments of the invention will now be described in detail, by way of example, and with reference to the accompanying drawings.
In the following description, the features described are to be considered as optional features of embodiments of the invention and features described with reference to one embodiment may be incorporated into another.
A harness embodying the invention has a forward attachment arrangement that includes a forward attachment assembly, as shown in
The forward attachment assembly comprises a body 30 and an attachment bar 32.
The body 30 has a generally oval or slight figure-of-8 peripheral shape and is formed from a single piece of metal by a combination of one or more of casting, forging and machining. The body 30 extends in a plane P, having inner and outer surfaces disposed to opposite sides of the plane, and its periphery can be considered as defining a region of the plane through which, six holes pass. The body is symmetrical about an axis A that extends within the plane and that forms a long axis of the body 30.
A bridge hole 40 is centred on the axis A approximately one third of the distance along the axis A from a first end of the axis A. The bridge hole 40 has shape that is square with rounded corners and has a dimension approximately one third of the width of the body 30 in the plane P transverse of the axis A.
A first and a second webbing slot 42, 44 are disposed to opposite sides of the axis A. Each slot 42, 44 extends from a small distance from the axis A that lies between the bridge hole 40 and a first axial end of the body 30, each slot 42, 44 being centred along an arc that is a constant distance from a proximal part of the periphery of the body 30.
There is an attachment hole 46 that extends symmetrically about the axis A to partially surround the bridge hole 40 and to extend to a second axial end of the body 30. This imparts the body 30 with a D-shaped attachment portion extending from the bridge hole 40 in a direction away from the webbing slots 42, 44.
All four above-described holes 40, 42, 44, 46 are formed with curved peripheries and without sharp corners to avoid the creation of stress risers within the body and within any object that is passed through the hole.
Two bolt holes 48 of circular cross-section pass through the body, at an axial position that is approximately half way along the axial extent of the bridge hole. Each bolt hole has one end portion, opening to the inner surface do the body 30, that is countersunk.
The attachment bar 32 has a central portion 50 of round cross-section and two securing portions 52. Each securing portion 52 has a flat mating surface. A bore extends through the securing portion 52 and opens perpendicular to the mating surface. At its opposite end, the bore has a hexagonal counterbore 56.
To assemble the forward attachment assembly a self-locking nut 58 is inserted into the hexagonal counterbore 56 of each bore in the attachment bar 32. A shaft of a respective cap screw 60 is inserted through each bolt hole 48 in the body from the countersunk end into a respective bore in the attachment bar 32 and then screwed into the nuts 58 in the attachment bar 32 and tightened such that the mating surfaces of the securing portions are clamped against the outer surface of the body 30.
The above described attachment arrangement can be incorporated into a harness described in
The attachment hole 46 defines a loop within the body to which a connector, such as a carabiner, can be connected. This can be used to attach anchors that will help a user to maintain a desired position, or as a point from which items can be carried.
The attachment bar 32 can be considered to be attached to the body 30 semi-permanently, in that it will not be removed during normal use of the harness. However, the connection is made in such a way that the flexible load-bearing member 28 can be removed and replaced as necessary, as part of a service operation, without the requirement that the user of the harness performs potentially risky procedures such as the formation of secure knots in the flexible load-bearing member 28.
It is possible to connect two flexible load-bearing members 28 to the same forward connection arrangement by passing the attachment bar through both of their loops 66, 66′, as shown in
The flexible load-bearing members 28 shown above are formed of rope. However, they may have other configurations, such as being made of webbing, as shown in
In the above-described embodiments, enhanced security of attachment of the flexible load-bearing members 28 is obtained with some loss of flexibility of application, in that the length of the flexible load-bearing members 28 cannot be adjusted. Therefore, in a modification to the embodiments described above, one forward attachment arrangement is provided with means to adjust the length of the flexible load-bearing member 28.
In a variation of the above embodiments, the flexible load bearing member 28 has at least one loop that is constructed in such a way as to limit the force that it can apply to the forward attachment arrangement during normal use to provide shock absorbance in the event that the harness acts to arrest a fall.
The principle of this design of these embodiments is that the attachment bar 32 is held within a double portion of webbing which is sewn together with a holding stitch and a further set of rippable stiches which once loaded by the bar, break sequentially to allow the bar to move through the webbing, effectively extending the length of the flexible load-bearing member 28 until an end-point is reached, with the result that the fall is arrested over a greater distance that would be the case where the loop is simply sewn at the end portion of the flexible load-bearing member 28.
In a first arrangement of a flexible load-bearing member 28 shown in
The flexible load-bearing member 28 is installed onto the forward connection arrangement by passing the attachment bar 32 between lengths of the webbing at the unstitched region 74.
During normal use, the attachment bar 32 is inserted into the unstitched region 74 to be held between the retaining stitches 72 and the holding stitches 76, and the holding stitches will bear the normal working load transferred from the harness through the flexible load-bearing member 28. The holding stitches 76 are configured such that they will fail in the event that the load applied to them by the attachment bar 32 exceeds a threshold that will be encountered during normal use of the harness, such as may arise during arrest of a fall. Once the holding stitches 76 have failed, load is transferred to the rippable stitches 78, which are intended to fail sequentially as the attachment bar 32 passes through them, effectively lengthening the flexible load-bearing member 28 to lessen the decelerative forces applied by the harness to the user. In the event that all of the rippable stiches 78 fail, the attachment bar will come up against the end of the webbing loop, which transfers load back to the retaining stitches 72, to apply sufficient force to arrest the user's fall.
In the modification of
The load limiting arrangement of
The arrangements of
A cam axle 142 extends between the blocks 134, 134′, and on it a cam 144 is carried such that the cam 144 can rotate on the axle 142. The cam 144 has a gripping surface 146 that faces generally towards the boss 138, the gripping surface being at a radial distance from the cam axle 142 that increases as the rotational distance of the gripping surface 146 from the boss 138 increases. The gripping surface extends onto a projecting lobe 148 of the cam 144. Gripping formations, such as transverse ridges or grooves, are formed on the gripping surface 146 to increase the friction that will occur between the gripping surface and an object sliding over it.
To assemble the forward attachment arrangement, a flexible load-bearing member 28 is passed through the bridge hole 40 and then placed between the blocks 134, 134′. The boss 138 and the carrier bolt 136 are then fitted, so trapping the flexible load-bearing member 28 between the boss 138 and the cam 144, with the flexible load-bearing member 28 being in contact with the gripping surface 146. The rope adjuster assembly 132 is then bolted to the body 30, which is the same as is the case in the other embodiments described herein.
The cam 144 and the flexible load-bearing member 28 are shaped and dimensioned such that when the cam 144 is rotated away from the body, such that the distance between the gripping surface 146 and the boss 138 is at its greatest, the flexible load-bearing member 28 is gripped, such that linear movement of the flexible load-bearing member 28 through the rope adjuster assembly 132 will urge the cam to rotate. Pulling the flexible load-bearing member 28 through the rope adjuster assembly away from the body 30 urges the cam to turn to a position that maximises the distance between the gripping surface 146 and the boss 138. In this position, the flexible load-bearing member 28 can pass through the rope adjuster assembly 132 with some resistance. If the flexible load-bearing member 28 is pulled in the opposite direction, this urges the cam 144 to rotate in a direction that would reduce the distance between the gripping surface 146 and the boss 138. If a user intervenes to prevent this rotation by applying force to the cam lobe 148, the flexible load-bearing member 28 can move linearly with some resistance. However, if the user does not intervene, the cam 144 will rotate so lessening the distance between the gripping surface 146 and the boss 138. This has the effect of clamping the flexible load-bearing member 28 between the cam 144 and the boss 138, thereby preventing further linear movement of the flexible load-bearing member 28. This allows the user to lengthen or shorten the flexible load-bearing member 28 as required.
An end part of the load bearing member 28 has a formation that prevents it from being fully withdrawn from the rope adjuster assembly 132 (for example, a loop 66 as described above or any other formation that increases its diameter sufficiently to prevent it passing between the cam 144 and the boss 138). This prevents the load bearing member 28 from becoming disconnected inadvertently as it is being lengthened by a user.
By suitable modification of the rope adjuster assembly, a flexible load-bearing member 28 formed from webbing can be used instead of one formed from rope.
In a variation shown in
It should be noted that it will normally be necessary to provide a rope adjuster assembly 132 on one of two forward attachment arrangements, with the other using a fixed connection, for example as described with reference to
Instead of lying within a flat plane P, the body 230 in this embodiment is curved, such that the attachment portion extends at a small angle (approximately 15° in this example).
The opening to each bolt hole 248 in the outer surface is surrounded by a ridge 254. At the inner surface, each bolt hole 248 is counterbored and is formed with a hexagonal cross-section 262 inwardly of the counterbore.
This embodiment further includes an attachment bar 232 that is broadly similar to that described above, with modifications as will now be described.
Each securing portion 252 is formed with a recess 264 that surrounds the bore where it emerges from the mating surface. The opposite end portion of the bore is countersunk at 256.
To assemble this embodiment, a self-locking nut 258 is inserted into the hexagonal counterbore 262 of each bolt hole 248. A shaft of a respective cap screw 260 is inserted through the bore of each securing portion 252 of the attachment bar 232. The attachment bar 232 is placed on the outer surface of the body 230 such that each ridge 254 is received in a corresponding one of the recesses 264. The shafts of the screws 260 are passed through the bolt holes 248 in the body 230 to come into threaded engagement with the nuts 258. The bolts are tightened such that the mating surfaces of the securing portions 252 are clamped against the outer surface of the body 230.
The presence of the ridges 254 and recesses 264 serve to locate the attachment bar 232 in the correct position on the body 230 and also prevents the attachment bar 232 being installed in the incorrect orientation. The length and diameter of the head of the screws 260 is selected such that if an attempt is made to fit the attachment bar 232 to the wrong surface of the body 230, the head will not enter the counterbores 262 of the bolt holes 248, and are not long enough to project from the attachment bar 232 so preventing the nuts 258 from being installed.
In the embodiment of
The knot blocking plate 280 has a periphery of size and shape such that when it is placed on the body 230 it completely covers the bridge hole 240. An inner surface of the knot blocking plate 280 has a projecting boss 282 surrounded by a flat mating surface. The boss 282 is a close fit within the bridge hole such that when the knot blocking plate 280 is placed onto the body 230, the mating surface comes into contact with the outer surface of the body 230 and the boss 282 enters the bridge hole 240 to locate the knot blocking plate 280 in the correct position on the body 230.
Two bolt holes 248 pass through the knot blocking plate 280. An end portion of each bolt hole 248 adjacent to the outer surface is countersunk at 286. A recess 288 surrounds each bolt hole 248 where it opens to the inner surface of the knot blocking plate 280. As with the attachment bar 230 described above, the presence of the ridges 254 and recesses 288 serve to locate the knot blocking plate 280 in the correct position on the body 230 and also prevents the knot blocking plate 280 being installed in the incorrect orientation. The length and diameter of the head of the screws 260 is selected such that if an attempt is made to fit the knot blocking plate 280 to the wrong surface of the body 230, the head will not enter the counterbores 262 of the bolt holes 248, and are not long enough to project from the attachment bar 232 so preventing the nuts 258 from being installed.
The knot blocking plate 280 has a central rope aperture 288 that extends between the inner and outer surfaces. The rope aperture 288 is shaped as a rounded rectangle and dimensioned such that two lengths of rope that will be used to form the bridge can pass through it side-by-side with little space between the ropes and the material surrounding the rope aperture 288. Adjacent to where it opens to the inner and outer surfaces of the knot blocking plate 280, the rope aperture 288 is flared in order that it presents no sharp or small-radius edges to a rope passing through it.
The rope bridge on a harness that uses the forward connection arrangement shown in
Although some components described above have been formed from rope and some from webbing, the skilled person will realise that, in many cases, one can be substituted for the other.
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