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WO2005079922A1 - Piece d'ancrage a absorption d'energie - Google Patents

Piece d'ancrage a absorption d'energie Download PDF

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Publication number
WO2005079922A1
WO2005079922A1 PCT/GB2005/000638 GB2005000638W WO2005079922A1 WO 2005079922 A1 WO2005079922 A1 WO 2005079922A1 GB 2005000638 W GB2005000638 W GB 2005000638W WO 2005079922 A1 WO2005079922 A1 WO 2005079922A1
Authority
WO
WIPO (PCT)
Prior art keywords
energy absorber
deployment
load
flexible elongate
casing
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/GB2005/000638
Other languages
English (en)
Inventor
Julian Renton
Peter Nott
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Keyguard Ltd
Original Assignee
Keyguard Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Keyguard Ltd filed Critical Keyguard Ltd
Publication of WO2005079922A1 publication Critical patent/WO2005079922A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • A—HUMAN NECESSITIES
    • A62—LIFE-SAVING; FIRE-FIGHTING
    • A62B—DEVICES, APPARATUS OR METHODS FOR LIFE-SAVING
    • A62B35/00—Safety belts or body harnesses; Similar equipment for limiting displacement of the human body, especially in case of sudden changes of motion
    • A62B35/04—Safety belts or body harnesses; Similar equipment for limiting displacement of the human body, especially in case of sudden changes of motion incorporating energy absorbing means
    • A—HUMAN NECESSITIES
    • A62—LIFE-SAVING; FIRE-FIGHTING
    • A62B—DEVICES, APPARATUS OR METHODS FOR LIFE-SAVING
    • A62B1/00—Devices for lowering persons from buildings or the like
    • A62B1/02—Devices for lowering persons from buildings or the like by making use of rescue cages, bags, or the like
    • A62B1/04—Single parts, e.g. fastening devices
    • A—HUMAN NECESSITIES
    • A62—LIFE-SAVING; FIRE-FIGHTING
    • A62B—DEVICES, APPARATUS OR METHODS FOR LIFE-SAVING
    • A62B35/00—Safety belts or body harnesses; Similar equipment for limiting displacement of the human body, especially in case of sudden changes of motion
    • A62B35/0043—Lifelines, lanyards, and anchors therefore
    • A62B35/0068—Anchors
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04G—SCAFFOLDING; FORMS; SHUTTERING; BUILDING IMPLEMENTS OR AIDS, OR THEIR USE; HANDLING BUILDING MATERIALS ON THE SITE; REPAIRING, BREAKING-UP OR OTHER WORK ON EXISTING BUILDINGS
    • E04G21/00—Preparing, conveying, or working-up building materials or building elements in situ; Other devices or measures for constructional work
    • E04G21/32—Safety or protective measures for persons during the construction of buildings
    • E04G21/3261—Safety-nets; Safety mattresses; Arrangements on buildings for connecting safety-lines
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04G—SCAFFOLDING; FORMS; SHUTTERING; BUILDING IMPLEMENTS OR AIDS, OR THEIR USE; HANDLING BUILDING MATERIALS ON THE SITE; REPAIRING, BREAKING-UP OR OTHER WORK ON EXISTING BUILDINGS
    • E04G21/00—Preparing, conveying, or working-up building materials or building elements in situ; Other devices or measures for constructional work
    • E04G21/32—Safety or protective measures for persons during the construction of buildings
    • E04G21/3261—Safety-nets; Safety mattresses; Arrangements on buildings for connecting safety-lines
    • E04G21/3276—Arrangements on buildings for connecting safety-lines
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04G—SCAFFOLDING; FORMS; SHUTTERING; BUILDING IMPLEMENTS OR AIDS, OR THEIR USE; HANDLING BUILDING MATERIALS ON THE SITE; REPAIRING, BREAKING-UP OR OTHER WORK ON EXISTING BUILDINGS
    • E04G21/00—Preparing, conveying, or working-up building materials or building elements in situ; Other devices or measures for constructional work
    • E04G21/32—Safety or protective measures for persons during the construction of buildings
    • E04G21/3261—Safety-nets; Safety mattresses; Arrangements on buildings for connecting safety-lines
    • E04G21/3276—Arrangements on buildings for connecting safety-lines
    • E04G21/329—Arrangements on buildings for connecting safety-lines with measures for dampening the fall

Definitions

  • This invention relates to an energy absorbing anchor and in particular to an energy absorbing anchor intended for use with height safety systems whereby it is attached to relatively fragile structures.
  • Height safety equipment is used to prevent personnel working at height from falling to the ground below.
  • a typical arrangement is where personnel wear harnesses attached to one end of a lanyard and the other end of the lanyard is attached to a cable such that it is free to move along the length of the cable.
  • the cable is fixed between anchors that are attached to a structure and personnel can then move freely along the length of the cable in order to access work areas that need attention such as maintenance.
  • More sophisticated cable systems are intended for long lengths of cable where access is required over a large area often requiring deviations in the line of the cable. These systems tend to use intermediate anchor points through which the cable passes in order to limit cable spans between anchors and to allow deviations such as corners and angle changes, often to follow deviations in a structure surface.
  • Sophisticated traveller devices have been developed to travel along the cable and pass over intermediate anchors, without any need to be detached from the cable. A person can then attach their lanyard to such a traveller device and move along the length of the cable across intermediate anchors.
  • Some cable systems are positioned to stop personnel from gaining access to the edge of a building and therefore avoid the possibility of falling.
  • the problem with such cable systems is that many maintenance tasks such as gutter clearing require access at the edge of buildings and so they are too restrictive.
  • the more usual cable systems allow personnel access to the edge of building but arrest a fall safely in the unfortunate event that someone should accidentally fall. These systems are known as fall arrest systems.
  • the loading on end and corner anchors on such systems can be high depending on the distance through which someone falls and whether there are falls by multiple personnel.
  • Cable system anchors typically perform two basic functions. The first is to hold the cable clear of the roof surface in normal access use by personnel so that the cable, particularly in mid span where it tends to sag, cannot scratch the roof protective coating. Also, the travellers that are attached to the cable and to personnel and which are free to move along the cable length to allow access along the cable system must be prevented from hitting the roof surface.
  • the second basic function is to withstand loading transmitted through the cable in a fall without over loading the anchor fixings to the roof surface, particularly with respect to tensile loading on the fixings and also damaging the roof to which the system is attached. Such over loading of the fixings, and/or damage to the roof would compromise the safety of the cable to which a faller or a number of fallers is attached before and after a fall event.
  • Fixings in relatively fragile roof sheeting are significantly stronger when loaded in shear than when loaded in tension. Therefore, the ability of the anchors to lie down in the plane of the roof is essential to enable the fixings to be loaded primarily in shear and therefore to maximise the safe loading limit on the fixings to the roof and the roof itself.
  • This type of anchor also has an inbuilt energy absorber that extends under a resisting load that does not exceed the said safe loading limit so that load transmitted through the cable and applied to the anchor is also maintained within the said safe loading limit.
  • the energy absorber is capable of relatively large extensions due to the plastically deformable material being held within the anchor as a coiled store.
  • this absorber should absorb as much energy as possible within the limitations of the strength of the roof fixings and the roof itself and that it should extend as little as possible to limit movement in the cable and therefore the distance through which fallers fall.
  • the distance through which a faller falls and the weight of the faller are components of energy being put into the system and therefore a large fall distance requires more energy absorption and so it is important to minimise the fall distance during the process of energy absorption.
  • This type of anchor tries to achieve this by maintaimng the force resisting extension of the absorber close to the said safe loading limit as far as is practicable bearing in mind the limitations of the absorbing mechanism itself.
  • the energy absorbing mechanism in this type of anchor utilises plastic deformation of a store of plastically deformable material.
  • plastic deformation there are several problems with using plastic deformation and these are addressed by the present invention. Firstly, the load at which plastic deformation takes place is hard to predict with accuracy because it depends on the exact mechanical condition and chemical composition of the plastically deformable material before plastic deformation. Secondly, the choice of plastically deformable material for the energy store, particularly in terms of cost and weight, is limited because the material needs to be both strong but also ready to yield and plastically deform.
  • the plastic deformation process itself changes the mechanical condition of the plastically deformable material tending to make it more brittle and this can affect the load required to plastically deform it and also reduce the ultimate braking load where there is likely to be a concentration of stress in the material that would otherwise migrate to other parts in a material which will yield more readily.
  • the plastic deformation process is irreversible in that the- plastically deformable material cannot be re-used.
  • one object of this invention is provide an energy absorbing anchor that is capable of functioning in any anchor position in a cable fall arrest system whether as an end anchor or an intermediate anchor.
  • Another object of this invention is to provide an energy absorbing anchor that supports the cable in normal access use of a cable fall arrest system (not involving a fall situation), so that the cable is held clear from the surface of the roof and traveller devices used by personnel to remain attached to the cable across intermediate anchors are also held clear of the roof surface.
  • Support to the cable should be maintained without any permanent deflection of the energy absorbing anchor until loading on the anchor transmitted through the cable exceeds a predetermined level, such as would typically occur in a fall event.
  • this predetermined level is limited by the strength of the fixings between the energy absorbing anchor, particularly the tensile component of loading on the fixings, and also the strength of the roof itself, hi order to establish a safe limit, it is typical to apply an additional safety margin of about 100%.
  • the limit should also be sufficiently high to avoid, as far as is practical, the energy absorbing anchor from deflecting prematurely as a result of accidental pulling on a fall arrest system cable during normal access use rather than during and after a fall event.
  • a further objective of this invention is to provide an energy absorbing anchor that orients towards the load applied through the cable when the said predetermined level of load is exceeded such that the loading on the fixings of the energy absorbing anchor to the roof surface is substantially in shear and therefore capable of sustaining a higher level of load, and whereby the energy absorbing anchor has an energy absorbing mechanism that uses friction to resist deployment of a flexible elongate in order to absorb energy such that the resisting load does not exceed the safe limit applied to anchor fixings to the roof and the roof itself when the said fixings are loaded substantially in shear.
  • this invention provides an energy absorber comprising: means for attaching the energy absorber to a supporting structure, means for attaching the energy absorber to a load element, and orienting means comprising at least one deformable element and responsive to a predetermined tensile load applied to the means for attaching to a load element to deform the at least one deformable element and to change the orientation of the energy absorber towards the direction of an applied load, and further comprising a store of flexible elongate material and friction deployment means to deploy the store of flexible elongate material and to provide resistance during said deployment and thereby absorb energy.
  • this invention provides an energy absorber comprising means for attaching the energy absorber to a supporting structure, means for attaching the energy absorber to a load element, a store of flexible elongate material and friction deployment means to deploy the store of flexible elongate material and to provide resistance during said deployment and thereby absorbing energy, a casing around the store of flexible elongate material and said friction deployment means, and further comprising orientation means including said casing and responsive to deployment of said flexible elongate material to change the orientation of the energy absorber by rotation about a lower rim of the casing towards the direction of the applied load.
  • this invention provides an energy absorber comprising means for attaching the energy absorber to a supporting structure, means for attaching the energy absorber to a load element, a substantially cylindrical casing, a store of flexible elongate material and friction deployment means to deploy the store of flexible elongate material and to provide resistance during said deployment and thereby absorb energy, further comprising orientation means including said casing and at least one deformable element responsive to a predetermined tensile load applied to the means for attaching to a load element to deform the at least one deformable element and to change the orientation of the energy absorbing anchor towards the direction of the applied load by rotation about a lower rim of the casing and whereby there is at least some deployment of the flexible elongate material during orientation.
  • the cable is held at about 200mm above the roof surface in normal access use of a fall arrest system (preceding a fall event), and that it is preferable orientation begins when the applied load on the said load element is about 2.5kN.
  • Lower loads initiating orientation can lead to the anchor being oriented accidentally during normal use of a fall arrest system rather than in the event of a fall accident.
  • fragile roof sheets may fail by buckling if orientation is initiated at applied loads of more than 5k-N and the fixings to the roof may become over loaded in tension tending to pull the fixings out of the roof. Therefore, a figure of 2.5 offers a 100% safety margin.
  • the maximum load that most fragile roofs and the fixings into the roof surface can withstand when the energy absorbing anchor has completed orientation towards the applied load and the fixings are load substantially in shear is approximately 20kN and so it is preferred to limit this to lOkN in order to maintain a 100% safety margin. It is therefore desirable that the applied load on the load element after orientation should not exceed the maximum safe limit that in practice has been found to be about lOkN.
  • Figure 1 shows a partially cut away view of an energy absorbing anchor according to a first embodiment of the invention
  • Figure 2 shows an elevation partially cut away view from a direction perpendicular to Figure 1;
  • Figure 3 a partially cut away plan view of Figure 1;
  • Figure 4 shows a partially cut away view of Figure 1 in operation
  • Figure 5 shows a partially cut away view of an energy absorbing anchor according to a second embodiment of the invention
  • Figure 6 shows a partially cut away view of Figure 5 in one level of operation
  • Figure 7 shows a partially cut away view of Figure 5 in a second level of operation
  • Figure 8 shows a partially cut away view according to a third embodiment
  • Figure 9 shows a detail of the embodiment in Figure 8.
  • Figure 10 shows a partially cut away view according to a fourth embodiment of the invention.
  • Figure 11 shows a partially cut away plan view of Figure 10
  • Figure 12 shows a partially cut away view of Figure 10 in operation
  • Figure 13 shows apian view of a typical base plate.
  • a length of flexible elongate material 1 is located around axial guide 2 dividing the length of the elongate material equally and each end of elongate material 1 is then coiled in the same rotational direction around cylindrical drum 3.
  • One end of elongate material 1 is then passed through drum 3 and around axle 4 and swaged to the other end of elongate material 1 by swage means 5 such that the ends of elongate material 1 are effectively joined.
  • Swage means 5 is located to the drum 3 such that it cannot move with respect to drum 3.
  • Drum 3 is located on axle 4 such that its central axis is coaxial with the central axis of axle 4 and is free to rotate about axle 4.
  • Base plate 7 is substantially rectangular with fixing positions such as 46 shown in Figure 13 at each corner and with a formed shape about its centre to provide stiffening such that when base plate 7 is fixed at each fixing position to a structure such as a fragile roof surface, loading on the fixings is, as far as is practicable, equally distributed across all fixings.
  • the type of fixings used is ideally a type that is readily available and easy to install such as stitching screws that can be pierced into a fragile roof surface and tightened in one operation. After base plate 7 is fixed to the surface of a fragile structure such as a roof sheet, base plate 7 is substantially parallel to the plane of the fragile structure surface.
  • the axial guide 2 is attached to a U bolt 6 which is attached in turn to the base plate 7.
  • the axial guide 2 is arranged such that it can orientate in all directions in the plane of base plate 7 with respect to U bolt 6.
  • U bolt 6 is fastened with nuts 47 and 48 to the centre of base plate 7 such that axial guide 2 is effectively connected to base plate 7.
  • Bracket 8 consists of two parallel plates held apart and joined at one end to form a U shape. Said one end of the bracket 8 is rigidly attached to load element 9 and casing 10. Axle 4 is located in locating holes in both parallel plates of bracket 8 such that its central axis is parallel to the plane of base plate 7 and perpendicular to the plane of the parallel plates. Drum 3, located on axle 4, is positioned between the parallel plates of bracket 8. Friction discs 11 and 12 are located at either end of drum 3 and with their disc axes coaxial with the central axis of axle 4 and with interlocking means between the friction discs 11 and 12 and drum 3 that constrains the said friction discs to rotate with drum 3.
  • Friction discs 11 and 12 are made of a friction lining material that has a relatively consistent coefficient of friction between itself and the material from which bracket 8 is made. The parallel plates of bracket 8 are then urged together, and against the friction discs 11 and 12, by spring discs 13 and 14 and bolts 15 and 16 such that the urging force generates a frictional resisting loading, resisting rotation of drum 3 with respect to bracket 8.
  • Spring discs 13 and 14 are intended to provide some axial elastic movement to ensure that compression between the parallel plates of bracket 8, and thus the urging force, can be maintained over a prolonged period.
  • Guide 18 is fixed by means of fastenings 49 and 50 to bracket 8 such that guide 18 cannot rotate with respect to bracket 8.
  • the purpose of guide 18 is to constrain the path of flexible elongate material from drum 3 to axial guide 2 such that it is aligned between load element 9 and U bolt 6 and remains aligned in the event of tensile loading between load element 9 and U bolt 6.
  • Casing 10 is cylindrical with a closed domed portion at its upper end, as shown in Figures 1, 2 and 4. Other types could be used, but a cylindrical casing is desirable for symmetry to ensure that the performance of the anchor is consistent regardless of the direction of the tensile load applied to load element 9.
  • casing 10 Along the length of casing 10 there are various weakening grooves shown as 20a to 20d that enable the casing to plastically deform when a sufficient predetermined compression load is applied between load element 9 and the lower rim of casing 10.
  • a load is generated in a fall situation transmitted through fall arrest system cable 40 typically in a direction parallel to the plane of base plate 10
  • casing 10 is urged to rotate about its lower rim.
  • the rotational moment about the rim of casing 10 is resisted by the connecting components between base plate 7 and load element 9 including the frictional resistance resisting rotation of drum 3 due to compression loading between the parallel plates of bracket 8 resisting deployment of elongate material 1.
  • casing 10 Below a predetermined level of applied load at load element 9 casing 10 remams rigid and resists rotation.
  • casing 10 plastically deforms in the region of the weakening grooves 20a to 20d, as shown in Figure 4, such that load element 9 rotates in the plane orthogonal to and with respect to base plate 7 and in a direction typically in the plane of base 7 towards the direction of the applied load at load element 9. Rotation in the plane orthogonal to base plate 7 will then continue until the rim of casing 10 slips away from base plate 7, whereupon, the energy absorbing anchor lies in an orientation substantially in the plane of base plate 7.
  • the friction discs 11 and 12 provide a consistent and known coefficient of friction with respect to bracket 8, as a result the load resisting rotation of drum 3 will be largely predictable and consistent. Therefore, by controlling frictional resistance through the choice of material for friction discs 11 and 12 and also the compression loading between the parallel plate of bracket 8 including the design and material specification for spring discs 13 and 14 and the torque applied on tightening bolts 15 and 16, the load applied at load element 9 can be effectively limited such that it does not exceed the safe limit for the strength of the fixings between base plate 7 and a fragile structure surface such as a roof sheet and also the safe limit for the strength of the fragile structure itself
  • the energy absorbing anchor has a rigid substantially cylindrical casing.
  • the casing is shown in Figure 5 as comprising a dome 41, cylinder 42 and interlinking discs 43 and 44 to represent a casing construction that is easy to manufacture.
  • the casing could equally be one component including a domed portion at its upper end and a cylindrical body portion.
  • the casing, being rigid, is not intended to substantially plastically deform.
  • Deployment of elongate material will cease after the rim of the casing has slipped away from base 7 and then recommence when the load applied to load element 9 increases to a second predetermined level that is sufficient to overcome the load resisting deployment of the elongate material 1.
  • energy is typically absorbed by means of deployment of flexible elongate material both during at least part of the orientation process and also after orientation of the energy absorbing anchor. After orientation, deployment of elongate material 1 will ' cease when the load applied to load element 9 is insufficient to overcome the load resisting deployment of flexible elongate material 1.
  • the applied load at load element 9 transmitted through fall arrest system cable 40 and sufficient to deploy elongate material is typically significantly less than the load resisting deployment of elongate material 1 between load element 9 and base 7. That is, the first predetermined load level is smaller than the second predetermined load level. This is because of the geometry of the casing in terms of the proportion of its height to the radius of its base. Hence, the reason why deployment stops temporarily after the lower rim of the casing, shown as 45 in Figure 6, slips away from base 7.
  • Figures 8 and 9 show the same embodiment as in Figures 5 to 7 except spacer plates 24 and 25 have been added.
  • One problem that can be encountered with a friction device of this kind is that when load is maintained between the friction lining discs 11 and 12 and bracket 8 over a long period of time, the load required to overcome the frictional resistance and initiate rotational movement of drum 3 can be greater than the load required to overcome frictional resistance whilst drum 3 is already rotating. This effect is often referred to as stiction. Therefore spacer plates 24 and 25 are intended to hold the parallel sides of bracket 8 apart and thereby release compression loading between discs 11 and 12 and bracket 8 until frictional resistance is required in a fall event.
  • the energy absorbing anchor has two drums 27 and 28, both cylindrical and with the same cylindrical outer diameter. Both drums 27 and 28 are located on axle 4 such that their central axes are coaxial with the axis of axle 4 and such that they are each free to rotate independently with respect to axle 4 and each other.
  • Flexible elongate material 29 is passed around axial guide 2 dividing the length of the elongate material equally. One end of the elongate material is coiled around drum 27 in one rotational direction and the other end of elongate material 29 is coiled around drum 28 in the opposite rotational direction. Each end is then looped around axle 4 and secured back on itself by means of swaging means 32 and 33 such that each loop is free to rotate about axle 4.
  • Friction disc 11 is located between drum 27 and one parallel plate of bracket 8 and friction discl2 is located between drums 28 and the other parallel plate of bracket 8, whereby friction disc 11 is constrained to rotate with drum 27 and friction disc 12 is constrained to rotate with drum 28.
  • a further friction disc 30 is located between drums 27 and 28 and constrained to rotate with drum 28.
  • Disc 31 has similar radial dimensions to friction disc 30, is ideally made of a material similar to bracket 8 and is constrained to rotate with drum 27.
  • the parallel plates of bracket 8 are then urged together by spring discs 13 and 14 and bolts 15 and 16 such that the urging force generates a frictional force which resists rotation of both drums 27 and 28.
  • drums 27 and 28 rotate is opposite directions deploying elongate material 29 equally from each drum.
  • the benefit of this arrangement is that it avoids the need for guide 18, shown in Figures 1 and 2, such that the resultant of the load on the elongate material 29 either side of axial guide 2 is aligned between load element 9 and axial guide 2. It also avoids the possibility of the flexible elongate material being damaged whilst bearing on guide 18, as shown in Figure 1, during deployment and avoids any undesirable effects as a result of friction between the flexible elongate material and guide 18.
  • the friction discs 11 and 12, and also 30 in respect of Figure 11 are constrained to rotate with the drum (or drums). This can be achieved in various ways such as applying an interlocking surface form to the adjacent surface of both the friction disc and drum. Alternatively, the friction discs could be adhered to the drum (or drums) by adhesive or some other means of surface bonding. Whilst the embodiments describe the friction discs being constrained to rotate with the drum or drums, the invention could also function if the friction discs are constrained to bracket 8 whereby the drum or drums effectively rotate against friction discs that are static with respect to the drum or drums.
  • the flexible elongate material can be multi-stranded steel cable such as galvanised steel cable or stainless steel cable and that the cable diameter can be about 5mm in diameter in order withstand expected loading during and after a fall event.
  • the flexible elongate may take any form provided that is has sufficient tensile strength and that this strength is not unacceptably compromised as a result of being coiled around a drum.
  • the drum may be made of a reinforced plastic because the loading applied through the flexible elongate material tends to be distributed over a relatively large area.
  • it could also be made from a variety of other materials and may be constructed of more than one component such as being made in two halves and joined. Construction from more than one component may be necessary in order for the drum to be readily manufactured.
  • the other components are ideally made from steel, treated and coated to protect against prolonged exposure to a variety of outside environmental conditions or else made of stainless steel.
  • the casing in all the above embodiments is shown as having a cylindrical body with a closed and domed upper end and with the cylindrical central axis aligned between the load element 9 and U bolt 6.
  • This central positioning of the cylindrical body enables the moment resisting its orientation to be the same irrespective of the direction in the plane of base plate 7 that it is tending orientate towards a load applied at the load element 9 typically as a result of a fall event.
  • the casing could have any other cross sectional geometry as may be beneficial particularly if the direction of the load applied at load element 9, typically in the plane of base plate 7, can be predicted.
  • the casing could have a rectangular base if the direction of the applied load at load element 9 could be predicted to be in either of two perpendicular directions with respect to the plane of the base plate 7. Also, a rectangular base could be arranged such that it could provide greater resistance to orientation in one direction as compared to another direction by arranging the distance between its rim and the line of load between the load element 9 and U bolt 6 to provide different resisting moments depending on the direction of the applied load at load element 9.
  • the casing could be an open structure but whereby it is sufficiently rigid to withstand typical compressive loading between load element 9 and U bolt 6 or, with respect to Figures 1 to 4, the casing could use some other means to plastically deform when the compressive loading between load element 9 and U bolt 6 reaches a predetermined level. For example, it may be that a thinner walled casing could be arranged to beneficially buckle when a predetermined compressive loading is applied between load element 9 and U bolt 6.
  • predetermined loads mean loads that are ideally predetermined with a consistent degree of accuracy although the degree of accuracy will depend on numerous factors such as consistency of materials, dimensional accuracy of components and variations in assembly methods and procedures. The degree of accuracy may also depend on variations in environmental conditions and whether the energy absorbing anchor is a recent installation or has been installed for a longer period. h all the above embodiments, if the flexible elongate material should ever be fully deployed, the swaging means for connecting the ends of the elongate such that the elongate is securely looped about axle 4 provides a secure attachment between load element 9 and base plate 7.
  • this attachment between load element 9 and base plate 7 should be capable of withstanding a load of at least twice the maximum load applied at load element 9 during deployment of the flexible elongate material.
  • the energy absorbing anchor should have a sufficient store of coiled flexible elongate material to absorb all the foreseen energy that could be generated in the worst case fall scenario within the scope of the fall arrest system and its installation.
  • the first predetermined level of load required to change the orientation of the energy absorbing anchor can be set by the amount of tightening of the bolts 15 and 16, which controls the compression loading between the relatively rotating parts of the energy absorbing anchor. Further, in all of the embodiments the tightening of the bolts 15 and 16 controls the second predetermined level of load required to begin deployment of the flexible elongate material from the drum or drums.
  • the present invention provides the advantage that the predetennined levels of load at which the energy absorbing anchor will change orientation or begin deployment can be set to a desired one of a range of possible predetermined loads by appropriate tightening of the bolts 15 and 16 without requiring changes in the components of the anchor.
  • a device using plastic deformation to absorb energy will change orientation and begin deployment at a fixed level of applied load.
  • an energy absorbing anchor according to the present invention has improved flexibility regarding the applied load levels to which it responds. hi practice it will usually be preferred to tighten the bolts 15 and 16 before the anchor is installed, for example on a roof. However, it will be possible to tighten the bolts after installation of the anchor if desired.
  • the first predetermined load at which the change of orientation of the anchor begins will be smaller than the second predetermined load at which deployment of the material from the store takes place for geometrical reasons.
  • the change of orientation should be enabled and the first predetermined load set by deformation of the casing, it will be understood that there is an upper limit to the first predetermined load level because if the load level at which deformation of the casing occurs is set too high the change of orientation will take place without deformation of the casing, similarly to the second embodiment.
  • first and second predetermined loads are a consequence of the shape of the energy absorbing anchor. If the anchor was sufficiently short relative to its diameter or width, the first and second predetermined loads could be the same or the second predetermined load smaller than the first. However, in practice it is usually preferred for the energy absorbing anchor to have a post like profile with a height considerably greater than, and usually several times greater than, its diameter.
  • the first predetermined level of load at which the change in orientation begins is set by the release of spacer plates 24 and 25 from between the parallel plates of bracket 8. This release is unrelated mechanically to the deployment of the elongated material and accordingly the first predetermined load level at which the change in orientation begins can be arranged to have any desired value relative to the second predetermined level of load at which the elongate material begins deployment.
  • the first and second predetermined levels of load are arranged to be substantially the same in order to maximize the amount of energy absorbed relative to the degree of movement of the load element 9.
  • the frictional loading resisting deployment of the elongated material is zero until the plates 24 and 25 are removed from between the parallel plates of the bracket 8.
  • the release mechanism is arranged to reduce the length of this frictionally unresisted movement as far as possible.

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Abstract

La présente invention concerne un système d'absorption d'énergie comprenant un dispositif conçu pour attacher le système d'absorption d'énergie sur une structure de support, un dispositif conçu pour attacher le système d'absorption d'énergie sur un élément de charge et un dispositif d'orientation. Ledit système d'absorption d'énergie comprend également au moins un élément déformable qui est sensible à une charge de traction prédéfinie appliquée sur le dispositif d'attache afin de déformer l'élément déformable et de modifier l'orientation du système d'absorption d'énergie en direction d'une charge appliquée. Le système d'absorption d'énergie comprend aussi une réserve de matière allongée souple et un dispositif de déploiement par frottement, conçu pour déployer la réserve de matière allongée souple et pour offrir une résistance lors de ce déploiement et donc absorber de l'énergie.
PCT/GB2005/000638 2004-02-21 2005-02-21 Piece d'ancrage a absorption d'energie Ceased WO2005079922A1 (fr)

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US40388604A 2004-02-21 2004-02-21
US0403886.5 2004-02-21

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Cited By (11)

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US20120286128A1 (en) * 2011-05-10 2012-11-15 Checkmate Limited Support post assembly for a safety line system
WO2012177675A3 (fr) * 2011-06-23 2013-07-18 Honeywell International Inc. Poteaux destinés à être utilisés dans une protection contre les chutes
WO2013061087A3 (fr) * 2011-10-27 2014-02-06 Latchways Plc Absorbeur d'énergie et dispositif de sécurité de système anti-chute
DE102015114821A1 (de) * 2015-09-04 2017-03-09 Bornack Gmbh & Co. Kg Seilaufnahme
EP3199722A3 (fr) * 2016-01-29 2017-08-09 QBM Distributors Ltd Ancrage de sécurité
US10328294B2 (en) * 2016-04-12 2019-06-25 Msa Technology, Llc Load indicator for a fall protection apparatus
WO2019175543A1 (fr) * 2018-03-13 2019-09-19 Latchways Plc Dispositif d'absorption d'énergie
WO2020201700A1 (fr) 2019-03-29 2020-10-08 Julian Elwyn Renton Absorbeur d'énergie et dispositif de sécurité
EP3906975A1 (fr) * 2020-05-06 2021-11-10 P. de Heer Holding B.V. Point d'ancrage pour un système antichute de personnel
WO2025003377A1 (fr) * 2023-06-29 2025-01-02 Msa Europe Gmbh Ensemble d'ancrage et procédé d'amortissement de la chute d'un utilisateur
DE102024110377A1 (de) * 2024-04-12 2025-10-16 Msa Europe Gmbh Ankerbaugruppe mit definierter auslösekraft und verfahren zur absorption eines sturzes eines benutzers

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WO2001087420A1 (fr) * 2000-05-18 2001-11-22 Keyguard Limited Absorbeur d'energie
GB2362448B (en) 2000-05-18 2002-06-05 Keyguard Ltd Energy absorber
WO2003039680A1 (fr) * 2001-11-05 2003-05-15 Rodolphe Argoud Dispositif d'ancrage de securite comportant un amortisseur de choc

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EP0373328A2 (fr) * 1988-11-18 1990-06-20 Sergio Verardo Sac dorsal antichute
GB2240757A (en) * 1990-01-27 1991-08-14 Ferranti Meters Ltd Denis Winched drum with safety devices
WO2001087420A1 (fr) * 2000-05-18 2001-11-22 Keyguard Limited Absorbeur d'energie
GB2362448B (en) 2000-05-18 2002-06-05 Keyguard Ltd Energy absorber
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WO2003039680A1 (fr) * 2001-11-05 2003-05-15 Rodolphe Argoud Dispositif d'ancrage de securite comportant un amortisseur de choc

Cited By (20)

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Publication number Priority date Publication date Assignee Title
US9387351B2 (en) * 2011-05-10 2016-07-12 Checkmate Limited Support post assembly for a safety line system
US20120286128A1 (en) * 2011-05-10 2012-11-15 Checkmate Limited Support post assembly for a safety line system
WO2012177675A3 (fr) * 2011-06-23 2013-07-18 Honeywell International Inc. Poteaux destinés à être utilisés dans une protection contre les chutes
US10569111B2 (en) 2011-06-23 2020-02-25 Honeywell International Inc. Posts for use in fall protection
US11311757B2 (en) 2011-06-23 2022-04-26 Honeywell International Inc. Posts for use in fall protection
CN103958002B (zh) * 2011-10-27 2016-08-24 拉奇韦斯公开有限公司 能量吸收器和坠落制动系统安全装置
US9670980B2 (en) 2011-10-27 2017-06-06 Latchways Plc Energy absorber and fall arrest system safety device
GB2509648B (en) * 2011-10-27 2016-03-09 Latchways Plc Energy absorber and fall arrest system safety device
GB2509648A (en) * 2011-10-27 2014-07-09 Latchways Plc Energy absorber and fall arrest system safety device
WO2013061087A3 (fr) * 2011-10-27 2014-02-06 Latchways Plc Absorbeur d'énergie et dispositif de sécurité de système anti-chute
DE102015114821B4 (de) 2015-09-04 2021-08-19 Bornack Gmbh & Co. Kg Seilaufnahme
DE102015114821A1 (de) * 2015-09-04 2017-03-09 Bornack Gmbh & Co. Kg Seilaufnahme
EP3199722A3 (fr) * 2016-01-29 2017-08-09 QBM Distributors Ltd Ancrage de sécurité
US10328294B2 (en) * 2016-04-12 2019-06-25 Msa Technology, Llc Load indicator for a fall protection apparatus
GB2571948B (en) * 2018-03-13 2022-02-23 Latchways Plc Energy absorber device
WO2019175543A1 (fr) * 2018-03-13 2019-09-19 Latchways Plc Dispositif d'absorption d'énergie
WO2020201700A1 (fr) 2019-03-29 2020-10-08 Julian Elwyn Renton Absorbeur d'énergie et dispositif de sécurité
EP3906975A1 (fr) * 2020-05-06 2021-11-10 P. de Heer Holding B.V. Point d'ancrage pour un système antichute de personnel
WO2025003377A1 (fr) * 2023-06-29 2025-01-02 Msa Europe Gmbh Ensemble d'ancrage et procédé d'amortissement de la chute d'un utilisateur
DE102024110377A1 (de) * 2024-04-12 2025-10-16 Msa Europe Gmbh Ankerbaugruppe mit definierter auslösekraft und verfahren zur absorption eines sturzes eines benutzers

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