GB2591984A - Safety Harness - Google Patents

Abstract

A safety harness for supporting a wearer working at height for use with a fall arrest system comprising leg straps (1, fig 1), shoulder straps 5 and belt section 3. Flexible straps 12 capable of supporting the wearer in the event of a fall are attach to both sides of the chest at a first end 10. The flexible straps are secured to straps on the harness by stitching 17, 18 designed to break under a predetermined load. When secured, the second end 11 of the flexible straps are positioned at waist level. When the load on the flexible straps exceed the predetermined level, the flexible straps are released from lower position and move to a higher position, supporting the wearer such that their centre of gravity is below the attachment point.

Description

Safety harness The invention relates to a harness for supporting a person working at height and in particular for use with a fall arrest system.

When working at height it is common to use a fall arrest system whereby a mechanical device runs on a rail, wire or similar and is adapted to automatically lock onto the rail in the event of a fall. Such systems are typically fitted to exposed ladders or structures such as telecommunications masts.

Safety harnesses are known, such harnesses normally comprising straps around the user's legs, over the user's shoulders and fastening across the chest. Attachment points for the connection of lanyards, lifelines or fall arrest systems are normally provided at the chest and rear, in the area of the user's upper back. Such attachment points are positioned above the user's centre of gravity such that, when supported by the harness, the user is maintained in an upright position. Such attachment points typically comprise a metal D ring or less often a pair of textile loops which are connected to simultaneously, the latter being more prevalent as a chest attachment point. Additionally, some harnesses are also equipped with a belt. Attachment points on the belt are usually positioned near the user's hips and are typically for support and not suspension due to the risk of the user becoming inverted by nature of the attachment point being below their centre of gravity. Such points are typically not used for the attachment of a fall arrest system. The risks to health from being suspended head down after a fall are significant, as are the risks of head injury or collision with a structure or other object when the user moves from an upright position to an inverted one during a fall. When using a fall arrest system as described it is preferable to have the attachment point on the harness positioned below the typical chest attachment point as this generally allows the fall arrest device to run freely along the rail. Furthermore, if the fall arrest device is attached to the upper, chest, attachment point it is left in the proximity of the user's face. This is an impediment to the user and has the potential to cause injury. The conflict between the desirability of positioning the attachment point low down to aid the free running of the fall arrest system versus the desirability of positioning higher up to improve the post fall suspension position obviously gives rise to problems in harness design and use.

Some known harnesses have an attachment point specifically for the attachment of a rail or wire fall arrest system mounted on a waist belt. Such harnesses have the problem that, in the event of a fall, the user is suspended from a point below their centre of gravity with the subsequent risk that they may become inverted. Other harnesses have a waist attachment point which, in the event of a fall, moves from its lower position below the user's centre of gravity to an upper position, above the user's centre of gravity by means of tearing of harness straps or stitching. Such harnesses have the problem that, post fall, the structure of the harness may be compromised or the additional straps necessary to incorporate the moving attachment point are so positioned as to detrimentally affect the fit of the harness. The position and increased complexity of such straps may also make the harness difficult to don.

The invention seeks to overcome these problems by providing a harness with a lower, attachment point to aid the free running of a fall arrest system when connected thereto and which moves to an upper position when the user is suspended in the event of a fall without compromising the integrity or fit of the harness.

According the present invention there is provided a harness comprising, leg straps, shoulder straps and waist belt section; a chest attachment point being formed from a pair of flexible loops, one either side of the chest, each of said loops formed from a length of elongate material with a first end securedly affixed back upon itself to form a first loop to which other harness straps are attached and a second end securedly affixed back upon itself to form a second loop with a single section of material therebetween and extending substantially parallel to the straps connecting the chest to the waist belt said second ends providing a second pair of flexible loops comprising a lower attachment point below the user's centre of gravity and characterised in that, in the event of a fall said loops break free from the associated straps when the force applied exceeds a predetermined threshold to leave the user suspended from the chest attachment loops.

Preferably the harness straps are free to move within the chest loops.

Preferably said chest loops may be configured such as to allow the harness straps to align advantageously with the load when the movable attachment point is in the upper position.

Preferably the extension between each chest loop and the associated attachment loop is encased within the harness strap when the movable attachment point is in the lower position.

Preferably said chest loops and extensions are comprised of rope or cord.

A preferred embodiment 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 harness with the movable attachment point in the lower position Figure 2 is a front view of the harness with the movable attachment point in the upper position Figure 3 is a view of one side of the front section only, with the movable attachment point in the lower position Figure 4 is a view of one side of the front section only, with the movable attachment point in the upper position Figure 5 is a view of one side of the front section only, with the movable attachment point in the lower position and one layer of webbing removed for clarity Figure 1 shows a harness comprising webbing leg straps 1 to encircle the user's thighs, each with a buckle or similar releasable adjustment means 2. A belt section 3 is also provided with similar releasable adjustment means 4. Shoulder straps 5, each with adjustment means 6 extend from each hip over the shoulder and back down to each hip via flexible chest loops or rings 10,20 and straps 8. By releasing buckles 2 and 4 the user may don the harness by placing the shoulder straps over their shoulders in the same way as donning a waistcoat. Closing buckle 4 and then buckles 2 around each leg followed by adjusting buckles 2,4 and 6 to achieve the desired fit. Where shoulder straps 5 cross at the rear an attachment point is provided in the form of a metal D ring or textile loop 7 securedly affixed thereto. This point may be used to connect the harness to a lanyard, lifeline or other fall arrest system. Further D rings 14, 24 may be provided on the belt 3 to allow the attachment of a 'pole strop' or similar work positioning lanyard, such lanyards being configured to support the user when in a standing position. A front attachment point is provided by connecting a lanyard or similar simultaneously to both loops 10, 20. Said front attachment point being configured to support the user when fully suspended in the harness.

Straps 9 extend from each chest loop 10, 20 substantially downwards to affix to belt 3 either side of buckle 4. Each of said loops 10,20 comprising a length of rope or cord with a first end folded back on itself and sewn or similarly securedly affixed to form a substantially circular loop. Said loop being of sufficient size to allow it to pass through loops in the ends of the straps 5,8, 9 thus forming a secure connection therebetween. A second end of each length of cord is folded back on itself and similarly securedly affixed to form an eye or loop 11, 21 leaving a single strand of cord 12 connecting ring 10 and eye 11. Strap 9 is composed of a double layer of webbing said two layers being held together by rows of stitching 17, 18. Said rows do not run the entire length of each side of strap 9 such that apertures 15, 16, 19 are formed. The rope or cord of loops 10, 20 passes through apertures 15, 19 at the upper end of strap 9, ropel2 passing between the two layers of webbing and between rows of stitching 17, 18 with eye 11, 21 protruding from aperture 16 at the lower end. A further attachment point is provided by connecting a fall arrest system to both loops'', 21. The positioning of this attachment point below the user's centre of gravity and its proximity to the waist renders it more suitable for use with fall arrest systems running on rails, wire or similar as previously described.

In the event that the user falls whilst attached to a rail or wire fall arrest system, the weight of the user is supported via the harness, through eyes 11, 21. Stitching or other securing means 17 is configured to tear when the load applied to it, via the upwards force from eyes 11, 21 exceeds a predetermined threshold. Thereby loops 11, 21 and ropes 12 are released from their lower positions and move to their upper positions under the weight of the user. This upper position, being above the user's centre of gravity supports the user in an upright position. The predetermined threshold at which rows of stitching or other means 17 begin to tear being above the load required to statically support the mass of the user but below that experienced by the user in the event of a fall being held by the fall arrest system.

When the loops 11, 21 are in their upper position the straps 5, 8, 9 are free to move around loops 10,20 such that they may align with the loads applied to the harness via the mass of the user.

Claims (8)

1. Claims 1. A harness comprising, leg straps, shoulder straps and waist belt section; a chest attachment point being formed from a pair of flexible loops, one either side of the chest, each of said loops formed from a length of elongate material with a first end securedly affixed back upon itself to form a first loop to which other harness straps are attached and a second end securedly affixed back upon itself to form a second loop with a single section of material therebetween and extending substantially parallel to the straps connecting the chest to the waist belt said second ends providing a second pair of flexible loops comprising a lower attachment point below the user's centre of gravity and characterised in that, in the event of a fall said loops break free from the associated straps when the force applied exceeds a predetermined threshold to leave the user suspended from the chest attachment loops.
2. 2. A harness according to claim 1 wherein the harness straps are free to move around the chest loops.
3. 3. A harness according to 2 wherein the chest loops may be configured such as to allow the harness straps to align with the load when the movable attachment point is in the upper position.
4. 4. A harness according to 1 wherein the extension between each chest loop and the associated attachment loop is encased within the harness strap when the movable attachment point is in the lower position.
5. 5. A harness according to claim 4 wherein said extensions and lower attachment loops are contained between two layers of webbing.
6. 6. A harness according to claim 4 wherein said extensions held in place by stitching or other means configured to release when the force applied to it exceeds a predetermined threshold.
7. 7. A harness according to claim 6 wherein said threshold being above the load required to statically support the user but below that experienced by the user in the event of a fall being held by the fall arrest system.
8. 8. A harness according to any preceding claim wherein the chest loops and extensions are comprised of rope or cord.