GB2483974A

GB2483974A - Fall arrest system with activation indicator

Info

Publication number: GB2483974A
Application number: GB201115840A
Authority: GB
Inventors: Kevan Herbert
Original assignee: APOLLO CRADLES Ltd
Current assignee: APOLLO CRADLES Ltd
Priority date: 2010-09-22
Filing date: 2011-09-14
Publication date: 2012-03-28
Anticipated expiration: 2031-09-14
Also published as: GB201115840D0; GB2483974B; GB201015904D0

Abstract

An automatic fall arrest and descend system to arrest the fall of a workman (9) wearing a safety harness (18) working at an elevated position and to automatically lower that workman (9) either to the ground (7) or to a safe area, comprises an automatic descender device (1); a descent rope (5), of length appropriate to a rescue height (10) through which the workman (9) is required to descend, passing through the descender device (1); a safety rope (15); a connector (16) connecting the descent rope (5) to the safety rope (15); an EN353/2 rope grab (22) normally slidable up and down the safety rope (15); a lanyard (21) connected to the rope grab (22) and provided with a connector (20) to attach the lanyard (21) to a safety harness (18) of the workman (9); and a constraint device (23) adapted, in use, to prevent the descent rope (5) being inadvertently pulled through the automatic descender device (1) by wind and/or workmen in the vicinity, and secondly to serve as a visual indicator of activation of the system by being fracturable at a predetermined loading.

Description

I

Title of the invention

Safety system

Field of the Invention

This invention relates to a safety system in the form of an automatic fall arrest and S descent system for a workman working at an elevated position above or below ground level.

Background of the Invention

Various devices are in use to provide elevated working positions, such as cradles suspended down the sides of multi-storey buildings, mast climbing work platforms, cherry pickers, located both outside and inside e.g. at indoor arenas etc, and safety requirements demand the wearing by operatives of an EN36I safety harness to prevent an unconstrained fall.

When a safety harness comes into use during an emergency, the suspended workman requires rescue within minutes, and the rescuers invariably incurs some risk to themselves in effecting the rescue.

One type of known rescue equipment used by rescue teams comprises a descender device, through which passes a descent rope of length appropriate to the rescue height and certified to carry the weight of two workmen. The basic technique is that, with the descender device safely anchored e.g. to the top of a building or similar, the rescuer, from a position above the workman to be rescued, clips his safety harness to the rope so that the rescuer is himself suspended from the rope, the resulting tension on the rope triggering operation of the descender device so that the rescuer commences a predetermined rate of descent. When the rescuer reaches the workman to be rescued, the safety harness of that workman is also clipped to the rope, and safe descent e.g. to ground level, of both the rescuer and the workman rescued, continues.

Object of the Invention A basic object of the invention is the provision of an automatic fall arrestor to arrest the fall of a workman from an elevated position and to automatically lower that workman to the ground, without the need for intervention by a rescuer.

Summary of the Invention

According to the inventiofl there is provided an automatic fall arrest and descend system to arrest the fall of a workman wearing a safety harness and working at an elevated position and to automatically lower that workman either to the ground or to a safe area, comprising (i) an automatic descender device; (ii) a descent rope, of length appropriate to a rescue height through which the workman is required to descend, passing through the descender device; (iii) a safety rope; (iv) a connector connecting the descent rope to the safety rope; (v) an EN353/2 rope grab normally slidable up and down the safety rope; (vi) a lanyard connected to the rope grab and provided with a connector/clip to attach the lanyard to the safety harness of the workman; and (vii) constraint device adapted, in use, firstly to serve to prevent the descent rope being inadvertently pulled through the descender device by wind and/or workmen in the vicinity, and secondly to serve as a visual indicator of activation of the system by being fracturable at a predetermined loading.

Advantages of the Invention The system in accordance with the invention, when installed in the vicinity of a workman working at an elevated position e.g. on a work platform, results in a fall arrest and a safe descent system being immediately and automatically available to that workman (or duplicated as many times as is required to provide one system for each workman), should the work platform etc malfunction. Thus, the workman, suspended in a safety harness, is not waiting sometimes hours for rescue, nor are rescue teams required to be on stand-by, nor is it necessary for any member of a rescue team to put themselves at risk in performing the rescue. Furthermore, the constraint device in its mode as a fracturable or rupturable visual indicator serves as a tell-tale device, such that if the system has been activated e.g. for a descent, it can only be legitimately installed for re-use following a positive inspection, and the re-issue and re-application of a fresh constraint device following a satisfactory inspection.

Preferred or Optional Features Means are provided either to anchor the safety rope at its lower end to the ground or to a safe level, or alternatively to apply a light weight to the lower end of the safety rope, so as to keep the safety rope taut at all times, allowing free movement of the EN353/2 rope grab.

The automatic descender device comprises a rotatable pulley around which the descent rope is wrapped.

The automatic descender device comprises a centrifugal brake to control the maximum speed of rotation of the pulley, and hence the rate of descent of a workman clipped to it.

The centrifugal brake is set to provide a rate of descent of circa 0.8m/sec.

The automatic descender device is attached to an EN353/2 anchor point via an EN362 connector.

The anchor point/connector has a 1 OkN load carrying capacity.

When a torque above a pre-set threshold is applied to the pulley by the safety rope, the centrifugal brake becomes activated and rotation to achieve lowering of the safety rope, will commence.

The descent rope comprises a dead length extending between a storage device and the pulley, and a live length after passage around the pulley and exit from the descender device.

The dead length storage device is a freely rotatable drum or a containment bag secured at a suitable anchor point.

An end of the live length of the descent rope is connected to an end of the safety rope by an EN362 rnaillon connector.

The corrected connector/clip on the lanyard for connection to a safety harness is an EN362 connector/clip.

The constraint device consists of a breakable cord, wire, rope or line.

A suitable breakable line is a standard angler's line with a known break strain.

The cord, wire, rope or line is connected between a shackle on a housing of the automatic descender device and the maillon connector.

The descent rope is a 10mm rope, complying with EN1891.

The safety rope is a 12mm rope complying with EN353/2.

The rope grab complies with EN353/2.

The descent and/or safety rope is of polyamide.

The rope grab is constructed in stainless steel.

The rope grab comprises an activation lever to which one end of the lanyard is connected, such that the weight of a workman falling is transmitted to the lever, and the resulting lever movement clamps the rope grab to the safety rope.

Drawing One example of automatic fall arrester and descent system in accordance with the invention is shown diagrammaticafly on the accompanying single sheet of drawings.

The device in accordance with the invention comprises an automatic descender device 1 of known construction, typically a MRG92P automatic descender, which is securely fixed via an anchor point 2, preferably to EN795 with a capability of lOkN, fixed at a suitable location e.g. to the top of a building 3 or other structures, such as a shaft, wind turbine etc. The automatic descender device 1 incorporates a rotatable pulley 4 around which a polyamide descent rope 5 is wrapped, and also incorporates a centrifugal brake (not shown) to control the maximum speed of rotation of the pulley 4.

A substantial portion of the descent rope 5 is coiled on a storage device 6, such as a freely rotatable drum, or a containment bag, and is of such length that considering the height above the ground 7 of a working platform 8 on which at least one workman 9 is working, in an emergency situation, the workman 9 may descend over a height 10 to the ground 7.

The descent rope 5 comprising a dead length 11 extending between the storage device 6 and the pulley 4, and a live length 12 after passage around the pulley 4 and exit from the automatic descender device 1.

End 13 of the live length 12 is connected to end 14 of a 12mm safety rope 15 of polyamide by an EN362 maillon connector 16, the safety rope extending to the ground 8 and maintained taught by being anchored at 17 to the ground 7.

The workman 9 wears an EN361 safety harness 18 to which is clipped by an EN362 connector 20 one end of a lanyard 21, of Im maximum length, capable of taking the weight of the workman 9, with the other end of the lanyard 21 connected to an EN 353/2, rope grab 22 normally slidable up and down the safety rope 15 so as not to impede normal movement of the workman 9.

The rope grab 22 comprises an activation lever (not shown) to which the lanyard is attached, such that the tension in the lanyard resulting from the fall of a workman, rotates the lever to clamp the rope grab 22 to the safety rope 15.

As a further safety feature for the entire system, a constraint device in the form of a fracturable/breakable/rupturable cord or line 23 of known breaking strain, is fitted between the anchor point 2 an the maillon connector 16, to provide a tell-tale, positive visual indication as to whether the automatic fall and arrest system has been activated or not. In the event of a broken cord or line 23, all the components require inspection and the issue and fitting of a fresh cord or line 23 before being available for re-use. Furthermore, the cord or line 23 serves not only as a visual indicator of activation, but also as a constraint device to prevent the 10mm rope from passing inadvertently through the automatic descender device I by means other than a fall i.e. due to wind load on the ropes, gentle pulling caused by movement of workmen etc Instead of lowering to the ground 8, the location 8 could simply be some other safe area.

Claims

Claims 1. An automatic fall arrest and descend system to arrest the fail of a workman wearing a safety harness and working at an elevated position and to automatically lower that workman either to the ground or to a safe area, comprising (i) an automatic descender device; (ii) a descent rope of length appropriate to a rescue height through which the workman is required to descend, passing through the descender device; (iii) a safety rope; (iv) a connector connecting the descent rope to the safety rope; (v) an EN35312 rope grab normally slidable up and down the safety rope; (vi) a lanyard connected to the rope grab and provided with a connector/clip to attach the lanyard to the safety harness of the workman; and (vii) a constraint device adapted, in use, firstly to serve to prevent the descent rope being inadvertently pulled through the automatic descender device by wind and/or workmen in the vicinity, and secondly to serve as a visual indicator of activation of the system by being fracturable at a predetermined loading.
2. A system as claimed in Claim 1, wherein means are provided either to anchor the safety rope at its lower end to the ground or to a safe level, or alternatively to apply a light weight to the lower end of the safety rope, so as to keep the safety rope taut at all times.
3. A system as claimed in Claim I or Claim 2, wherein the automatic descender device comprises a rotatable pulley around which the descent rope is wrapped.
4. A system as claimed in Claim 3, wherein the automatic descender device comprises a centrifugal brake to control the maximum speed of rotation of the pulley, and hence the rate of descent of a workman clipped to it.
5. A system as claimed in Claim 4, wherein the centrifugal brake is set to provide a rate of descent of circa 0.8m/sec.
6. A system as claimed in any preceding claim, wherein the automatic descender device is attached to an EN795 anchor point via an EN362 connector.
7. A system as claimed in Claim 6, wherein the anchor point/connector has a lOkN load carrying capacity.
8. A system as claimed in Claim 4, and any claim appended thereto, wherein when a torque above a pre-set threshold is applied to the pulley by the safety rope, the centrifugal brake becomes activated and rotation to achieve lowering of the safety rope, will commence.
9. A system as claimed in Claim 3, and any claim appended thereto, wherein the descent rope comprises a dead length extending between a storage device and the pulley, and a live length after passage around the pulley and exit from the descender device.
10. A system as claimed in Claim 9, wherein the dead length storage device is a freely rotatable drum or a containment bag secured at a suitable anchor point.
11. A system as claimed in Claim 9 or Claim 10, wherein an end of the live length of the descent rope is connected to an end of the safety rope by an EN362 maillon connector.
12. A system as claimed in any preceding claim, wherein the connector/clip on the lanyard for connection to a safety harness is an EN362 connector/clip.
13. A system as claimed in any preceding claim, wherein the constraint device consists of a breakable cord, wire, rope or line.
14. A system as claimed in Claim 13, wherein a suitable breakable line is a standard angler's line with a known break strain.
15. A system as claimed in Claim 13 or Claim 14, when appended to Claim 11, wherein the cord, wire, rope or line is connected between a shackle on a housing of the automatic descender device and the maillon connector.
16. A system as claimed in any preceding claim, wherein the descent rope is a 10mm rope, complying with EN 1891.
17. A system as claimed in any preceding claim, wherein the safety rope is a 12mm rope complying with EN353/2.
18. A system as claimed in any preceding claim, wherein the rope grab complies with EN35312.
19. A system as claimed in any preceding claim, wherein the descent and/or safety rope is of polyamide.
20. A system as claimed in any preceding claim, wherein the rope grab comprises an activation lever to which one end of the lanyard is connected, such that the weight of a workman falling is transmitted to the lever, and the resulting lever movement clamps the rope grab to the safety rope.
21. A system as substantially herein before described with reference to the accompanying drawing.