GB2451499A

GB2451499A - Safety harness arrangement

Info

Publication number: GB2451499A
Application number: GB0715008A
Authority: GB
Inventors: Christopher Jon Massey
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-08-02
Filing date: 2007-08-02
Publication date: 2009-02-04
Also published as: GB0715008D0

Abstract

A fall-arrest safety harness arrangement comprises a chassis 6 anchored by a chain to a fixed point 4 and a winding mechanism 9 mounted on the chassis. A tether 7 extends from the winding mechanism to a harness worn by a user 5. The winding mechanism is braked when a user has not fallen and is operated manually or by a motor or controlled by a brake to raise or lower the user as required after a fall. In one construction there may be a fixed-length restraint connected to the harness of the user in addition to the connection of the tether 7. The tether winding mechanism may include a load limiting lock mechanism and may include an inertia reel device.

Description

A HARNESS ARRANGEMENT

The present invention relates to harness arrangements and more particularly, harness arrangements utilised with respect to protection of personnel operating at elevated positions especially within the construction industries.

It will be understood with a wide range of industries and activities it is necessary to work at elevated positions. With regard to buildings and other structures such elevated positions may include placing of suspended flooring or roof panels relative to fixed frames. In such circumstances, in order to provide protection and limit fall distances it is generally known to provide a safety harness secured through an appropriate restraining chain to a fixed mounting point. In such circumstances, the worker in the harness, should they fall, will be limited to the extent of the restraining chain. The fixing point may be a beam clamp or lifting eye in the construction frame or may comprise a specifically located cleat or other mounting in order to protect the worker. In such circumstances, the protection system is similar to that utilised with regard to rock climbing. However, with respect to construction workers it will be appreciated are within a frame in comparison with rock climbing situations so there is little opportunity after a fall to grab a rock face or otherwise tn order to support themselves. In such circumstances, the wearer of the harness may suffer suspension trauma, kidney failure and in any event may knock their head during a fall rendering them unconscious. Suspension trauma relates to the harness itself digging into the wearer's body and preventing blood flow etc. It is typically expected that a suspended person will suffer further injury and may even die if not released from their suspended position within ten minutes.

In the above circumstances with a fixed chain restraint it will be understood that a co-worker or rescuer in such circumstances must be able to either lift the fallen operative or lower that operative to a position where they can be recovered and rescued. Clearly, a fixed restraint necessitates the co-worker to be sufficiently strong to lift their fallen colleague whilst lowering the fallen colleague depends upon a capability of extending the fixed restraint which by its nature has a fixed length to limit the height of the fall before restraint. In such circumstances, use of previous fixed restraints and a safety harness has inherent limitations.

In accordance with aspects of the present invention there is provided a harness arrangement comprising an anchor and a tether, the anchor secured to a chassis frame, the tether associated with a winding mechanism mounted on ihe chassis frame in order to provide at least part of a restraint in use, the winding mechanism regulating extension and/or retraction of the tether.

Generally, the anchor comprises a chain and a fastener for securing IS the arrangement to a fixed mounting.

Typically the tether has a harness coupling. Generally, the tether comprises a cable.

Typically, the tether incorporates a load limiter to limit load applied to the winding mechanism. Generally, the apparatus includes a tether lock.

Possibly, the tether lock comprises an inertia reel.

Generally, the arrangement includes a restraint chain. lypically, the restraint chain is separate from the tether. Generally, the restraint chain is directly coupled to the chassis by a restraint mounting. Typically, the restraint mounting is releasable to allow extension of the tether beyond a length determined by the restraint chain. Typically, the restraint chain has a fixed length.

Generally, the chassis forms part of a box. Typically, the box provides an enclosure for the winding mechanism. Typically, the box provides a store for the anchor and/or tether when not in use.

Generally, the winding mechanism comprises a winch and/or a friction clutch and/or governor brake. Typically, the winding mechanism is manually operable. Alternatively, the winding mechanism is driven by a motor.

Possibly, the tether is associated with a tension sensor. Typically, the tension sensor is associated with an alarm and the tension sensor has a load threshold such that when a load greater than the load threshold is applied to the tether a signal is provided to the alarm in order to stimulate the alarm to provide an indication. Possibly, the indication is an audible and/or visible signal. Possibly, the winding mechanism is associated with a control device whereby when the load sensor determines a load is applied to the tether greater than the load threshold the winding mechanism automatically extends the tether at a desired rate. Advantageously, the winding mechanism continues to extend the tether until the load sensor determines the load is below the load threshold. Possibly, the control device incorporates a time delay before extending the tether when the load threshold is exceeded.

Typically, the tether incorporates an edge protector Possibly, the edge protector comprises a roller and an edge form to engage an edge over any obstruction to present the roller with at least the tether extending over the roller Possibly, the winding mechanism incorporates means to vary the rate of extension or retraction of the tether. Possibly, the means for varying the rate of extension or retraction of the tether comprises a gear box with selectable gear ratios.

Aspects of the present invention will now be descnbed by way of example and reference to the accompanying drawings in which: -Figure 1 is a schematic illustration of a harness arrangement in accordance with aspects of the present invention; Figure 2 is a further schematic illustration of a harness arrangement in accordance with aspects of the present invention with a user just about to topple from an elevated platform; Figure 3 is a schematic depiction of the arrangement depicted in figure 2 with the user suspended; Figure 4 is a schematic view of a suspended user where a tether is configured IS to also act as a fixed restraint; Figure 5 is a schematic illustration of a third embodiment of a harness arrangement in accordance with aspects of the present invention; and, Figure 6 is a schematic side view of an edge protector in accordance with aspects of the present invention.

As indicated above working at elevated heights necessitates provision of safety procedures. Typically, these safety procedures will incorporate use of a harness and an appropriate restraint in order to limit the depth of fall.

Such restraints previously have comprised a fixed restraint in the form of a chain generally over specified for the potential fall loading which may be applied. In such circumstances, these restraints are of a fixed length and therefore either require for rescue excessive strength for lifting and lowering may cause even greater difficulties. The problem is that these restraints by their nature are of a fixed length in order to limit the extent of a fall.

Figure 1 provides a schematic illustration of a harness arrangement 1 in accordance with aspects of the present invention. The harness arrangement 2 comprises an anchor 2 generally in the form of a chain secured through a mounting or fastener coupling 3 to a fixed point 4. This fixed point 4 will be of a robust nature and will generally take the form of part of a frame or building structure or otherwise which can support and provide a robust location for the arrangement 1 in accordance with aspects of the present invention when a user 5 is freely suspended.

JO In accordance with aspects of the present invention the arrangement includes a thassis 6 to which the anchor 2 is secured at one end and a tether or lanyard 7 secured at the other end by an appropriate coupling such as a carabineer or gated clip 8. In such circumstances, through the anchor 2, the chassis 6 and the tether 7 it wilt be understood that the user 5 in normal operation is effectively secured by the fixed length of the chain 2, chassis 6 and tether 7 Thus, the height to which the user 5 can fall is limited by this fixed length.

In accordance with aspects of the present invention the tether 7 in a basic embodiment as depicted in figure 1 is secured directly to a winding mechanism 9. tn normal operation, that is to say when the user 5 has not fallen, the winding mechanism 9 is locked by an appropriate brake or other mechanism. As the winding mechanism 9 is secured upon the chassis 6 as indicated above the effective fixed length of the arrangement I is determined by the anchor 2, chassis 6 and tether 7. As indicated above such a fixed length limits the drop or fall depth of the user 5.

Once the user 5 has fallen in accordance with aspects of the present invention the winding mechanism 9 is rendered operative to enable the tether 7 to be extended or retracted in the direction of arrowheads 10 to enable the user to be lifted or lowered as appropriate. In such circumstances, even though the user 5 may not be able to clamber or climb up or down due to their injuries or an unconsciOus state it will still be possible to remove the user 5 from their suspended position within a desirable time period to avoid Suspension trauma.

The winding mechanism 9 will typically operate through a hand crank or ratchet 11 in order to turn the mechanism 9 and so extend or retract the tether 7 in the direction of arrowheads 10.

The chassis 6 generally takes the form of a sub-frame and that sub-frame may be part of a box 12 to enable convenient transportation and location of the arrangement in use. The chassis 6 is generally free and not mounted in any way to a support surface 13. The chassis 6 depends upon the anchor 2 to the fixed point 4 for retention of position upon the surface 13.

As indicated above generally in normal use, that is to say when the user 5 has not fallen, the winding mechanism 9 will be restrained and stopped in terms of extension and retraction of the tether 10 by a brake 14. This brake 14 may a simply friction brake which can be released fully or partially in order to allow the tether 7 to lower the user 5. Clearly, the rate of lowering the user 5 must be regulated and therefore the winding mechanism 9 will incorporate the friction brake or otherwise to limit the rate of fall in the direction of arrowhead when the brake 14 is released. In such circumstances the user 5 will be progressively lowered under the influence of gravity. Typically, the rate of fall will be relatively low to avoid further injury to the user 5 but may be adjusted if that user requires more immediate medical attention and it is possible to provide a soft landing through use of cushion bags or otherwise as the user 5 is lowered to a ground or lower level. Lowering may be beneficial as this will avoid pulling the user 5 over an edge 16 which may cause further injury. In any event, generally it will be easier for rescue and medical services to be provided at a ground or lower level.

The basic embodiment of the present invention described with respect to the harness arrangement 1 in figure 1 is dependent upon the mounting of the winding mechanism 9 to the chassis 6. In such circumstances the weight of the user 5 when falling will be applied to the clip 8 and the winding mechanism 9. Such loadings may necessitate larger or more robust winding mechanisms 9 then will be generally convenient for transportation and manipulation in use It will be understood that the present harness arrangement is a safety device and therefore should have limited effect upon the convenience of providing a safe working environment for the user 5 and to avoid resistance to use. In such circumstances, in may be beneficial to provide a separate fixed restraint as wefl as a tether in accordance with I 0 aspects of the present invention.

Figure 2 and figure 3 illustrate provision of a fastener arrangement 20 in accordance with further embodiments of aspects of the present invention.

As previously an anchor 22 typically in the form of a chain is secured to a fixed point 24 at one end and to a chassis 26 at another end. The chassis 26 may form part of a box shown by broken line 32. This box 32 may incorporate handles 39 and/or a lifting hook 40 to enable location and movement of the arrangement 20 in accordance with aspects of the present invention.

In accordance with the further embodiment depicted in figures 2 and 3 a separate fixed length restraint 38 is combined with a tether 39 in accordance with aspects of the present invention. The respective fixed restraint 38 and tether 37 are secured about an edge protector 27 to prevent fraying of either the tether 37 or the fixed restraint 38.

In normal use as previously a fixed restraint length is provided by the anchor 22 secured to the fixed point 24 at one end in combination with the chassis 26 and the fixed length restraint 38 secured to a harness 21 about a user 25 through a fixed restraint coupling 36 and a tether coupling 23.

As depicted in figure 2 the user 25 is still supported upon an elevated platform 41 just before falling and therefore both the fixed length restraint 38 and the tether 37 will be relatively loose and flaccid. The user 25 is shown just prior to topple from the elevated platform 41. in use the arrangement 20 in accordance with aspects of the present invention can operate in two principal ways. Firstly, as depicted in figure 2 both the fixed length restraint 38 and the tether 37 may be secured to the harness 21 through the couplings 23, 36. In such circumstances the tether 37 will be relatively loose as indicated as will the fixed length restraint 38 until the user 25 topples. When the user 25 topples the fixed length restraint 38 will limit the fail of the user 25.

The fixed length restraint 38 wiLl be relatively robust and as with the anchor 22 will typically take the form of a relatively heavy duty chain. In such circumstances, loading to the tether 37 will be limited so that potential damage to a winding mechanism 29 is avoided. With both the tether 37 and the fixed length restraint 38 secured it will be understood that the fixed length restraint 38 will prevent lowering of the user 25. Nevertheless, the winding mechanism 29 will enable the user 25 to be lifted up to a support surface 33 for appropriate recovery. To enable the user 25 to be lowered it will be appreciated that the coupling 36 must be released as depicted in figure 3 to enable lowering in the direction of arrowheads 35. This may be difficult if the user 25 is unconscious or a co-worker to user 25 cannot gain access to the coupling 36 Nevertheless, with the coupling 36 released from the harness 21 as indicated the user 25 can be lowered as appropriate upon the tether 37.

An alternative may be for the user 25 to be coupled to the fixed length restraint 36 during normal operation and the tether 37 only attached should that user fall. In such circumstances the arrangement may depend upon the user 25 being sufficiently competent, conscious, and able to attach the tether coupling 23 to the harness 21 to enable retraction and therefore lifting of the user 25 or release of the coupling 36 to allow lowering to the tether 37 and the winding mechanism 29. This again may not be acceptable for a practical recovery procedure.

In the above circumstances it is generally advantageous to provide as illustrated in figure 2 the fixed length restraint 38 connected through the coupling 36 as well as the tether 37 connected through the coupling 23 to the harness 21 of the user 25. In such circumstances, should the user 25 fall the fixed length tether 38 can be released through a chassis restraint coupling 42 being released from the chassis 26. In such circumstances again the user 25 will then be suspended upon the tether 37 and may lifted or allowed to be lowered in the direction of arrowhead 35 (figure 3). The released fixed length restraint 38 through the coupling 42 can then be utilised in a number of ways.

For example, the fixed length restraint 38 may be secured to a further safety connector to ensure that if the tether 37 should snap or the winding mechanism 29 fail the user 25 is again protected by a further now extended fixed length restraint. Alternatively, the fixed length restraint 38 may be allowed to fall below the user 25. If the fixed length restraint 38 falls below the user 25 it will be appreciated that this may then be caught by personnel upon a landing or ground surface 43 to limit or prevent swaying of the user 25. It will be understood that a user 25 swaying in the wind or otherwise may collide with surfaces or sharp edges. In such circumstances the fixed length restraint 38 dangling below the user 25 will enable that restraint 38 to act as a guide limiting such swaying or allowing the fallen uses to be pulled in to an intermediate landing surface or platform.

It will be understood that the winding mechanism 29 is integral to aspects of the present invention. In such circumstances, the winding mechanism 29 as indicated can comprise a hoist or winch operated by a hand crank or ratchet in order to lift a lower the user 25 in use on the tether 37.

Alternatively, the winding mechanism 29 may be driven by a motor to lift or lower the user 25 through the tether 37. Further alternatively, the winding mechanism may simply unwind against a friction brake or clutch. In such circumstances, once the friction brake or clutch is released the tether 37 will gradually lower the user 25 at a rate determined as necessary to ensure that the user 25 is lowered to the surface 43 in appropriate time to avoid trauma and further injury. The rate will be determined by operational requirements but will generally be in the order to 1 to 10 metres per minute.

A further aspect to the present invention is that a rescue unit can be provided by the arrangement 20 in accordance with aspects of the present invention. In such circumstances the chassis 26 in the form of a box may be transported to a location where a user has already fallen but is restrained by a previous conventional fixed length restraint chain from an anchor point. In such circumstances an arrangement 20 in accordance with aspects of the present invention may be secured to that anchor point and the tether 37 simply secured to the user as appropriately to allow lifting or lowering as required. To allow lowering the conventional fixed length tether will be released at the fixing point or where secured to the users harness.

Figure 4 provides a further alternative embodiment of aspect of the present invention. In this embodiment the tether is arranged to also act as an initial fixed length restraint. As previously a chassis 56 is again secured relative to a support surface 53 through an anchor 52 secured to a fixed point 54. The tether is associated with a winding mechanism 59 secured upon the chassis 56. In such circumstances as depicted in figure 4 an effective fixed length restraint is provided by the anchor 52 and a tether 57 associated with the winding mechanism 59. In order to further enhance the fixed nature of the restraint one or both of a load limiter or lock mechanism 50, 60 is utilised to prevent extension or retraction of the tether 57. It will be appreciated the lock mechanisms 50, 60 as indicated also acts as load limiter devices relative to limiting the load applied to the winding mechanism 29 should a user 55 fall. If the lock mechanism 50 is simply operated it will be appreciated that the effective restraint length of the tether 57a is limited by the tether coupling 63 to a harness 61 of the user 55. If the lock mechanism 50 is not provided then the lock mechanism 60 then limits the restraint length to the combination of the anchor 52, the chassis 56 and the length of the tether 57 beyond the lock mechanism 60. In either event the distance to fall by the user 55 is restrained to the fixed length and the arrangement includes the winding mechanism 59 as a secondary safety mechanism preventing at least a too rapid fall off the user 55.

Once the fall of the user 55 is restrained by the lock mechanisms 50, either separately or in unison the user can then be lowered by releasing the mechanisms 50, 60 and then utilising the winding mechanism 59 as described above. It will also be understood that the user 55 could be lifted by such an approach through a reversal in the direction of the winding mechanism 59.

Figure 5 provides a further alternative with regard to aspects of the present invention. As described above a tether 27 may be secured to a users harness 21 along with a fixed length restraint. Such an arrangement may be Is inconvenient for use and therefore as indicated the tether may only be secured to the harness when the user requires lowering or lifting subsequent to a fall. This too may be inconvenient. In such circumstances, as depicted in figure 5 a fixed length restraint 78 may be secured to a chassis 76 or as depicted by broken line 78a directly to a fixed point 74. In either event the fixed length restraint 78 limits the fall of a user 75. However, should the user faIl a tether 77 in accordance with aspects of the present invention can be more conveniently attached to the fixed length restraint 78 through an intermediate coupling 79. This intermediate coupling 79 may comprise a link coupling or an oversized link in a chain forming the fixed length restraint 78 such that an association with a remaining part 78b is achieved with a harness 71 associated with the user 75. Once a tether coupling 72 is associated with the intermediate coupling 79 it will be appreciated that in a first version of the arrangement depicted in figure 5 a fixed restraint coupling 73 can then be released from the chassis 76 to enable the user to be lifted or lowered. In an alternative arrangement where a prior known fixed length restraint extends directly from the hard fixed point 74 it will be understood that the chassis 76 as part of a housing 70 can be taken to the site of an incident and the anchor 72 is then associated with the fixed point 74 such that the otherwise free chassis 76 is robustly secured. In such circumstances, the tether 77 can then be attached to the intermediate coupling 79 and the user 75 lifted or lowered as required. It will also be understood that if further safety features are required a fixed restraint section as depicted between the coupling 73 and the intermediate coupling 79 from the chassis 76 could be added but generally this will be superfluous as the original fixed restraint extending directly from the fixing point 74 will still be associated with the hames 71 of the user 75. It will also be understood that this original fixed restraint chain could also be attached to the chassis 76 as a safety feature.

As previously a winding mechanism 80 wilt enable the tether 77 to lift and lower the user 75 relative to a ground surface 83 or an elevated platform 82.

As will be appreciated tethers in accordance with aspects of the present invention generally take the form of cables rather than previous chains. There is a greater likelihood of fraying if the tether should engage edge portions of a support platform. In such circumstances as depicted in figure 6 an edge protector is provided. The edge protector 100 will be located upon a tether 101 and incorporate an edge grab form 103. In such circumstances, as the tether 101 is moved down or up the edge grab form 103 will grab an edge 104 of a support platform 105 in order to present a roller part 106 upon which the tether 101 can act without or with a reduced likelihood of fraying.

The tether 101 at one end incorporates a harness coupling 107 to operate as described previously whilst another part of the tether 101 as described above will be secured to a chassis to a winding mechanism on a chassis to extend and retract the tether 101 in use. In such circumstances, as described previously a tether 101 will allow a user who has fallen to be lowered or lifted as required through the winding mechanism. As previously the tether 101 can be separate from a fixed length chain or otherwise in order to provide basic fall protection or be associated with that chain in use.

Whilst endeavoring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.

Claims

Claims 1. A harness arrangement comprising an anchor and a tether, the anchor secured to a chassis frame, the tether associated with a winding mechanism mounted on the chassis frame in order to provide at least part of a restraint in use, the winding mechanism regulating extension and/or retraction of the tether.
2. An arrangement as claimed in claim 1 wherein the anchor comprises a chain and a fastener for securing the arrangement to a fixed mounting.
3. An arrangement as claimed in claim I or claim 2 wherein the tether has a harness coupling.
4. An arrangement as claimed in claim 3 wherein the tether comprises a cable.
5. An arrangement as claimed in any preceding claim wherein the tether incorporates a load limiter to limit load applied to the winding mechanism.
6. An arrangement as claimed in any preceding claim wherein the apparatus includes a tether lock.
7. An arrangement as claimed in claim 6 wherein the tether lock comprises an inertia reel.
8. An arrangement as claimed in any preceding claim wherein the arrangement includes a restraint chain.
9. An arrangement as claimed in claim 8 wherein the restraint chain Is separate from the tether.
10. An arrangement as claimed in claim 8 or claim 9 wherein the restraint chain is directly coupled to the chassis by a restraint mounting.
11. An arrangement as claimed in claim 10 wherein the restraint mounting is releasable to allow extension of the tether beyond a length determined by the restraint chain.
12. An arrangement as claimed in claim 8 and any claim dependent thereon wherein the restraint chain has a fixed length.
13. An arrangement as claimed in any preceding claim wherein the chassis forms part of a box.
14. An arrangement as claimed in claim 13 wherein the box provides an enclosure for the winding mechanism.
15. An arrangement as claimed in claim 13 or claim 14 wherein the box provides a store for the anchor and/or tether when not in use.
16. An arrangement as claimed in any preceding claim wherein the winding mechanism comprises a winch and/or a friction clutch and/or governor brake.
17. An arrangement as claimed in any preceding claim wherein the winding mechanism is manually operable.
18. An arrangement as claimed any claim 1 to 16 wherein the winding mechanism is driven by a motor.
19. An arrangement as claimed in any preceding claim wherein the tether is associated with a load sensor.
20. An arrangement as claimed in claim 19 wherein the tension sensor is associated with an alarm and the tension sensor has a load threshold such that when a load greater than the load threshold is applied to the tether a signal is provided to the alarm in order to stimulate the alarm to provide an indication.
21. An arrangement as claimed in claim 20 wherein the indication is an audible and/or visible signal.
22. An arrangement as claimed in claim 19 and any claim dependent thereon wherein the winding mechanism is associated with a control device whereby when the load sensor determines a load is applied to the tether greater than the load threshold the winding mechanism automatically extends the tether at a desired rate.
23. An arrangement as claimed in claim 19 and any claim dependent thereon wherein the winding mechanism continues to extend the tether until the load sensor determines the load is below the load threshold.
24. An arrangement as claimed in claim 19 and any claim dependent thereon wherein the control device incorporates a time delay before extending the tether when the load threshold is exceeded.
25. An arrangement as claimed in any preceding claim wherein the tether incorporates an edge protector.
26. An arrangement as claimed in claim 25 wherein the edge protector comprises a roller and an edge form to engage an edge over any obstruction to present the roller with at least the tether extending over the roller.
27. An arrangement as claimed in any preceding claim wherein the winding mechanism incorporates means to vary the rate of extension or retraction of the tether.
28. An arrangement as claimed in claim 27 wherein the means for varying the rate of extension or retraction of the tether comprises a gear box with selectable gear ratios.
29. A harness arrangement substantially as hereinbefore described with reference to the accompanying drawings.