Systems and methods for absorbing energy of a lifeline for fall arrest

Abstract

Systems and methods are provided for a fall limiting device. An example device includes a housing having a lifeline therein and a fall arrest mechanism configured to apply a braking force to the lifeline based on motion of the lifeline. A polymeric tube enclosing at least part of a reserve portion of the lifeline can be configured to be retained in the housing during a first, normal operating condition. The fall limiting device can be configured to allow the retained portion of the lifeline to extend from the housing during a second, fall operating condition, wherein the fall arrest mechanism is configured to apply the braking force to the lifeline during the second operating condition. The polymeric tube may function to absorb the braking force applied to the lifeline in order to reduce the peak forces experienced by a user.

Description

SYSTEMS AND METHODS FOR ABSORBING ENERGY OF A LIFELINE FOR FALL ARRESTCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims the benefit of priority to GB Application No. 2310958.0, filed July 13, 2023, which is hereby incorporated by reference in its entirety for all purposes.BACKGROUND

[0002] In height safety applications, such as, for example, working on a building roof, it is common for a fall limiting device, such as a self-retracting lanyard (SRL), to provide a safe connection between a user wearing a harness and a structure or a safety line. In normal operation, the fall limiting device allows a lifeline to be output from the fall limiting device to allow the user some freedom of movement. In the event of a fall, the fall limiting device may include mechanisms for arresting the fall while maintaining the integrity of the fall limiting device and lifeline so as to avoid or limit injury. Such fall arrest mechanisms function to limit the forces on a user’s body during a fall by slowly bringing the user to a stop. If the peak forces experienced by a user exceed a certain threshold, the user may be injured.SUMMARY

[0003] Systems and methods are provided herein for a fall limiting device having a reserve line in contact with a compressible component, such as a polymer material. When a fall arrest mechanism applies a braking force to a lifeline, the compressible component may undergo compression to help reduce the stopping forces experienced by the falling user. In some aspects, the compressible component may take the form of a polymeric tube surrounding a portion of the reserve line, or a polymeric pad positioned underneath the reserve line (e.g., on a drum around which the lifeline is wound). By adding this additional compressible component, safety standards can be maintained without having to adjust the fall arrest mechanism or extend the length of the reserve line.

[0004] In one aspect, the present disclosure provides a fall limiting device. The fall limiting device may include a housing having a lifeline therein, a fall arrest mechanism configuredto apply a braking force to the lifeline based on motion of the lifeline, and a compressible tube enclosing at least part of a reserve portion of the lifeline. The reserve portion of the lifeline may be configured to be retained in the housing during a first operating condition. The fall limiting device may be configured to allow at least a portion of the reserve portion of the lifeline to extend from the housing during a second operating condition, wherein the fall arrest mechanism is configured to apply the braking force to the lifeline during the second operating condition.

[0005] In another aspect, the present disclosure provides a lifeline for a fall limiting device. The lifeline may include a lifeline cable having a first end configured to connect to a safety harness and a second end configured to attach to an internal drum hub of a fall limiting device housing, wherein a reserve portion of the lifeline is at least partially enclosed by polymeric tube, and wherein the reserve portion is positioned on the second end of the lifeline. In one embodiment the polymeric tube is compressible.

[0006] In one aspect, the present disclosure provides another fall limiting device. The fall limiting device may include a housing having an internal drum hub with a cylindrical hub surface, a lifeline at least partially wrapped around the drum hub, a polymeric pad at least partially positioned between the lifeline and the cylindrical hub surface, and a fall arrest mechanism configured to apply a braking force to the drum hub based on motion of the lifeline. The polymeric pad may be configured to undergo compression between the lifeline and the drum hub when the braking force is applied.

[0007] In another aspect, the present disclosure provides a method of arresting a fall of a user. The method may include: providing a housing having a lifeline therein, wherein the housing is connected to a structure and the lifeline is connected to the user; paying out a portion of the lifeline from the housing while retaining a reserve portion of the lifeline in the housing during a normal operating condition, wherein a polymeric tube encloses at least part of the reserve portion of the lifeline; paying out the reserve portion from the housing during a fall operating condition; and activating an arrest mechanism to apply a braking force to the lifeline based on paying out the retained portion. In one embodiment, the polymeric tube is compressible.BRIEF DESCRIPTION OF DRAWINGS

[0008] FIG. 1 is a diagram depicting a safety line system securing a person performing construction operations at the top of a structure.

[0009] FIG. 2 is a diagram depicting a fall limiting device.

[0010] FIG. 3 A is a diagram depicting a fall limiting device operating in a first, normal operating condition.

[0011] FIG. 3B is a diagram depicting a fall limiting device during a second, fall operating condition.

[0012] FIG. 4 is a diagram depicting a fall limiting device with a reserve portion of the lifeline extended from the housing of the fall limiting device. The reserve portion of the lifeline includes a polymeric tube.

[0013] FIG. 5 is a diagram depicting a lifeline subassembly with a polymeric tube enclosing at least part of a reserve portion of the lifeline.

[0014] FIG. 6 is a diagram depicting a fall limiting device with a polymeric pad partially wrapped around a cylindrical hub surface of an internal drum hub. For clarity purposes, the polymeric pad is shown in an unwound, partially detached form.

[0015] FIG. 7 is a diagram depicting a section of a fall limiting device with a polymeric pad partially wrapped around a cylindrical hub surface of an internal drum hub.

[0016] FIG. 8 is a polymeric pad configured to be partially wrapped around a cylindrical hub surface of an internal drum hub of a fall limiting device.

[0017] FIG. 9 is a flowchart depicting a method of arresting a fall of a user.

[0018] FIG. 10 is a graphical depiction of experimental results comparing the energy capacity of a fall limiting device having metal reserve line (dotted line) and a fall limiting device having a polymeric tube covering the metal reserve line (solid line).DETAILED DESCRIPTION

[0019] A fall limiting device, such as a self-retracting lanyard (SRL), may be designed to output (pay out) a portion of a lifeline from its housing during normal operation to allow a connected user (e.g., a harnessed technician) some freedom of movement while retaining a portion of the lifeline within the housing. Fall limiting devices may utilize a fall arrest mechanism (i.e., abraking mechanism) that is activated based on increased motion of the lifeline, such as centrifugal force at a drum holding the lifeline caused by a falling user. However, many fall arrest mechanisms require a minimum length of lifeline to be present within the housing (e.g., wound around the drum) to properly function during a fall event. Accordingly, were a fall limiting device to allow the entirety of the lifeline to be paid out, that fall arrest mechanism may not be able to be activated. By retaining a reserve portion of the lifeline within the housing during normal operations but allowing that retained portion of the lifeline to be paid out or extended during a fall condition, the fall arrest mechanism may be properly activated such that injury to the user is avoided or mitigated.

[0020] Because the fall arrest mechanism must rely on only the limited length of the reserve line when the rest of the lifeline is paid out, bringing a falling user to a resting state without subjecting them to dangerous forces can be a challenge. One option to limit the peak forces experienced by a user during a fall arrest is to reduce the mean force provided by the fall arrest mechanism. However, if the mean force of the fall arrest mechanism is reduced, the arrest distance may need to be increased. Increasing the arrest distance is unfortunately not an option in many cases, and some safety standards specifically require a maximum arrest distance (e.g., one meter).

[0021] The present disclosure provides systems and methods that overcome the aforementioned challenges by relying on a deformable material to absorb some of the peak forces applied by a fall arrest mechanism to the reserve line. In some aspects, a reserve portion of a lifeline may be substantially retained around a drum hub and at least a portion of the compressible material may be configured to undergo compression between the lifeline and the drum hub when a braking force is applied (i.e. during a fall arrest). This compression may help reduce the peak force experienced by a user connected to the lifeline. In one example, the deformable material may be positioned between the reserve line and a drum hub, such as a polymer pad on the surface of the drum of the fall limiting device. In another example, the deformable material takes the form of a casing (e.g., a polymer casing) enclosing the reserve line itself. Through the deformation of the added material, the peak forces experienced by a user during a fall may be substantially reduced.

[0022] Although the present disclosure is discussed primarily for applications involving an arresting the fall of a harnessed user, it should be readily appreciated that other usages for the systems and methods described herein are possible. For instance, the teachings described herein may be more generally applied to any application involving a fall arrest mechanism and anassociated drum, including, for example, transportation or movement of sensitive equipment that need to be safely secured from a fall.

[0023] FIG. 1 depicts a safety line system securing a person performing construction operations at the top of a structure. The system includes a first rigid member 102 that takes the form of a vertical post extending from a horizontal component 104 of the structure. The first rigid member 102 may be connected to the horizontal component 104 via mechanical means such as bolts, screws, adhesive, or otherwise. A safety line 106 is connected to the first rigid member 102 and runs horizontally between the first rigid member 102 and a second rigid member (not shown). A user 108 performing construction operations wears a harness 110 via which the user 108 is connected to the safety line 106 via a tether 112 having a connector 114. The safety line arrangement of FIG. 1 enables the user 108 to traverse the structure, anywhere within a tether length of the safety line. A fall limiting device (not shown) may replace the connector 114 and connect to the tether 112 or directly to the harness 110 of the user 108. In accordance with examples described herein, the fall limiting device may be configured to pay out some of the lifeline during normal operation to allow the user 108 some freedom of movement, while a reserve portion of the lifeline may be retained within the fall limiting device during a first, normal operating condition.

[0024] FIG. 2 depicts an example fall limiting device 200. The fall limiting device 200 may include a connection device 202 configured to attach to an object to be secured, such as a harness worn by a user. The connection device 202 may be attached to a lifeline (contained within the housing 204 of this depiction and therefore generally not visible) that may be wound around a drum 212 contained within a housing 204 of the fall limiting device 200 when not in use, as shown. As will be further described, a compressible component (not depicted) may be at least partly interposed between the drum and at least a portion of the lifeline. During a fall event, at least part of the compressible component may be effectively squeezed (i.e. compressed) between the drum 212 and the lifeline in order to mitigate the peak forces experienced by a user connected to the connection device 202. The lifeline may take a variety of forms including, for example, a single metal line, a braided metal line, a single synthetic material line, a synthetic material line made from multiple strands, or a natural material line made from multiple strands. An attachment piece 206 may serve to secure the housing 204 to a supported, stationary structure. The attachment piece 206 may take a variety of forms, including a hook, clip, loop, ring or carabiner.

[0025] FIG. 3A depicts a fall limiting device 300 operating in a first, normal operating condition. The fall limiting device 300 is shown connected to a structure 330 via an attachment piece 306. The structure 330 may take a variety of forms including a wall, a line (as depicted in FIG. 1), a horizontal structure (e.g., floor), or a roof. A user 308 is also shown connected to the fall limiting device 300 via a lifeline 310 having a portion of its length wrapped around a lifeline drum 312 inside a housing 314 of the fall limiting device 300. With this arrangement, the user 308 may be connected to the lifeline 310 of the fall limiting device 300 via a connection device such as a hook, clip, loop, or carabiner when performing a work task. The lifeline drum 312 may be biased by a spring or other mechanism that reels in the paid out lifeline 310 when not under tension by the user 308.

[0026] A fall arrest mechanism 340 may also be contained within the housing 314 and configured to arrest the lifeline 310 in the event of an incident (e.g., a fall) by limiting the rotation of the drum, and therefore the motion of the lifeline 310. The fall arrest mechanism 340 may act alone or in combination with other fall arrest mechanisms (e.g., inline energy absorbers connected between the lifeline 310 and the user 308, between the attachment piece 306 and the structure 330) to halt and mitigate damage from to the user 308 during a fall. The fall arrest mechanism 340 may be deployed based on motion (e.g., acceleration, centrifugal force initiated by a fast pay out) of the lifeline 310. In certain examples, the fall arrest mechanism 340 may be deployed based on forces experienced when the lifeline 310 is paid out at more than a threshold rate. The fall arrest mechanism 340 may be attached to the lifeline drum 312. For example, the fall arrest mechanism 340 may include one or more pawls that rotate from a stowed position to an engaged position based on centrifugal force provided by rotation of the lifeline drum 312 when the lifeline 310 is paid out at a high rate of speed, such as during a fall condition. Additional details regarding fall arrest mechanisms may be found, for example, in U.S. Patent Application No. 17 / 710,365, filed March 31, 2022, the entirety of which is herein incorporated by reference.

[0027] In a first, normal operating condition, such as when the user 308 is safely performing a task (i.e. not falling), the fall limiting device 300 may be configured to allow a portion of the lifeline 310 to be paid out from the housing of the fall limiting device 300 to provide the user 308 some freedom of movement. In this manner, the user 308 may move around a worksite without the fall limiting device 300 substantially impeding their movement. Accordingly, a fallarrest mechanism 340 of the device 300 may be in a disengaged state during this first, normal operation. Furthermore, any reserve portion of the lifeline 310 may remain within the housing 314 during such a first, normal operation. The retention of a reserve portion of the lifeline 310 during a first, normal operating condition may help ensure that a sufficient amount of lifeline 310 (e.g., a one meter length) is retained within the housing 314 to induce sufficient rotation of the lifeline drum 312 to engage the fall arrest mechanism 340 during a second, fall operating condition.

[0028] FIG. 3B depicts a fall limiting device 300 during a second, fall operating condition. As shown, the user 308 remains connected, via lifeline 310 to the fall limiting device 300, which is still connected to the structure 330 via the attachment piece 306. As shown by the arrow in this example, the user 308 is falling in a downward direction away from the fall limiting the device 300. In response, the fall limiting device 300 transitions from a normal, first operating condition, to a second, fall operating condition (e.g., a fall condition, an abnormal condition, an alarm condition, an alert condition, an emergency condition). In some aspects, the fall limiting device 300 entering the second, fall operating condition may result in various actions beyond simply arresting the fall of the user 308. For instance, an alarm condition where an audible alarm from the fall limiting device 300 is emitted or a signal is transmitted from an antenna on the fall limiting device 300 (e.g., to a server that tracks operation data (e.g., to monitor safety protocol compliance), alerts authorities of an alarm condition to initiate sending of help).

[0029] As shown, in the second, fall condition, part of the reserve portion of the lifeline 310 (i.e., the portion of the lifeline 310 substantially retained in the housing during the first, normal operating condition) has been extended to the outside of the housing of the fall limiting device 300. The fall limiting device 300 may be specifically configured to allow part of the retained portion of the lifeline 310 to extend from the housing 314 only during such a second, fall operating condition. Likewise, the fall arrest mechanism 340 may be configured to apply a braking force to the lifeline 310 during the second, fall operating condition. As described further herein, a compressible tube 320 (e.g., a polymeric tube) may enclose at least part of a reserve portion of the lifeline (i.e. the portion retained in the housing 314 during a first, normal operating condition) in order to dampen the peak forces experienced by the user 308 when the fall arrest mechanism 340 activates. In other words, the compressible tube 320 surrounding the reserve line may compress to absorb some of the initial peak forces experienced by the user 308 when the reserve line is paidout. By incorporating the compressible tube 320, the user can more comfortably come to a safe resting position during a fall.

[0030] In some examples, a reserve retainer 316 may be attached to the lifeline 310 so as to limit an amount of the lifeline 310 that may be paid out. For instance, the reserve retainer 316 may be attached at a specific point on the lifeline 310, such as between strands of the lifeline 310 in cases where the lifeline 310 is formed of a synthetic material comprising a plurality of strands. When the point on the lifeline 310 having the reserve retainer 316 reaches the threshold of the fall limiting device 300 at a lifeline stop (not depicted) (e.g., a slot that is wide enough for the lifeline 310 to pass through but not the wider reserve retainer 316), the interaction of the reserve retainer 316 and the lifeline stop may prevent further output of the lifeline 310 from the fall limiting device 300 during the first, normal operating condition. Accordingly, a reserve retainer may function to keep a reserve portion of the lifeline 310 within the housing 312 unless the user 308 experiences a fall event, in which case the reserve retainer may no longer function to keep the reserve line within the housing 312 (e.g., a lifeline stop disconnects or breaks away from the housing). It should also be appreciated that other alternatives to a reserve retainer for maintaining a reserve portion of the lifeline are possible.

[0031] FIG. 4 depicts yet another fall limiting device 400 with a reserve portion of the lifeline 410 extended from a housing 414 of the fall limiting device 400. As shown, a compressible tube 420 may cover substantially all of the reserve portion of a lifeline 410 extending from the lifeline drum 412 to a reserve retainer 416. The compressible tube 420 may be constructed to be compressed during activation of a fall arrest mechanism. In other words, the portion of the compressible tube 420 that is then located between the drum 412 and the lifeline 410 may be effectively squeezed therebetween during a fall arrest. Although the compressible tube 420 is depicted as covering substantially all of the reserve line, the compressible tube 420 may instead cover only a portion of the reserve line. For instance, the compressible tube 420 may cover at least one quarter, or more specifically at least one half of the reserve line. The compressible tube 420 may be positioned starting from the drum end of the reserve line, or instead positioned starting from the user end of the reserve line (i.e., only covering a half of the reserve line starting from the reserve retainer 416 and going up the reserve line). Furthermore, although the compressible tube 420 is often described as a coating or tubing on the reserve portion of the lifeline herein, it shouldbe appreciated that other configurations are possible. For example, the reserve line may be a separate line that is connected to the lifeline 410, and the compressible tube 420 may be replaced with a solid polymeric compressible reserve line (i.e., not a tubing).

[0032] FIG. 5 depicts a lifeline subassembly 500 of a fall limiting device having a compressible tube 520 enclosing at least part of a reserve portion of the lifeline 510. As shown, the reserve portion of the lifeline 510 may be positioned between a reserve retainer 516 and a lifeline connecter 522. The lifeline connecter 522 may be configured to securely attach the lifeline subassembly 500 to a lifeline hub or other internal component of a fall limiting device. The compressible tube 520 may be specifically configured to absorb some of the peak forces experienced by a user of a fall limiting device during a fall. The compressible tube 520 may have a thickness that allows the fall limiting device to safely bring a user to rest. For instance, the wall thickness (i.e. the radius of the compressible tube 520 minus the radius of the reserve line 510) may be at least 1 millimeter, at least 1.5 millimeters, at least 2 millimeters, or specifically about 3 millimeters. The compressible tube 520 may be located exclusively on the lifeline 510, and the lifeline 510 may be otherwise free of any polymeric tubing.

[0033] FIG. 6 depicts a fall limiting device 600 with a polymeric pad 650 partially wrapped around a cylindrical hub surface of a lifeline hub 612 contained within a housing 610. For clarity purposes, the polymeric pad 650 is shown in an unwound, partially detached form. When completely assembled, the polymeric pad 650 may be interposed between the hub surface and the lifeline 610 wrapped around the hub 612. In this manner, the polymeric pad 650 may function in a similar manner to the compressible tube previously described herein, by compressing to absorb the peak forces associated with a fall.

[0034] FIG. 7 depicts a sectional view of a fall limiting device 700 with a polymeric component 750 (e.g., pad) partially wrapped around a cylindrical hub surface of a lifeline hub 716. As shown, the polymeric pad 750 may include a first aperture 752 configured to allow access for tools to reach hub fasteners configured to secure a lifeline 710 to the lifeline hub 716. A second aperture 754 may provide an access point for the lifeline 710 to pass through the polymeric pad 750 and securely connect to the lifeline hub 716. By including apertures only where necessary, the polymeric pad may beneficially cover a substantially all of the surface of the lifeline hub 716. However, instead of including access apertures, the polymeric pad may instead cover only aportion of the surface of the lifeline hub 716 (e.g., at least half of the surface) leaving a portion of the surface of the lifeline hub 716 open for access and connection points.

[0035] FIG. 8 depicts polymeric pad 850 configured to be partially wrapped around a cylindrical hub surface of an internal lifeline hub of a fall limiting device. The polymeric pad 850 may include a first aperture 852 and a second aperture 854. An adhesive component may be included on an interior surface 856 of the polymeric pad 850 in order to attach the polymeric pad 850 to a surface of an internal lifeline hub. The adhesive component may be an integrated part of the interior surface 856 or may instead be physically separate therefrom (e.g., a doubles-sided) adhesive tape). Other attachment techniques may instead be used to secure the polymeric pad 850 to the lifeline hub. For instance, the polymeric pad 850 may be directly overmoulded or otherwise directly integrated with the cylindrical hub surface of the internal lifeline hub. Similar to the polymeric tubing previously described herein, the polymeric pad 850 may have a suitable thickness in order to compress to absorb a sufficient amount of the peak energy associated with a fall arrest. For instance, the wall thickness of the polymeric pad 850 may be at least 1 millimeter, at least 1.5 millimeters, at least 2 millimeters, or specifically about 3 millimeters. The thickness of the polymeric pad 850 may be dependent on the material relied upon.

[0036] A polymeric material may be used in the compressible tubes and pads described herein and may be specifically chosen to provide adequate force absorption during activation of a fall arrest mechanism to a reserve line. Accordingly, the polymeric material may be specifically chosen to have an adequate thickness and suitable material properties. For instance, as discussed, the polymeric material may have a wall thickness of at least 1 millimeter, at least 1.5 millimeters, or more specifically at least 2 millimeters. However, if the polymeric material exceeds a certain wall thickness, it may take up excess volume within the housing of the fall limiting device, which can cause volume issues. Accordingly, the polymeric material may have a wall thickness of less than 10 millimeters, or more specifically less than 5 millimeters. The polymeric material may have a small enough hardness value that it may provide adequate compression when squeezed between the drum hub and the reserve portion of the lifeline. For instance, the polymeric material may have a hardness of less than 80° IRHD, of less than 70° IRHD, or more specifically about 60° IRHD. Similarly, in order to avoid being too soft to adequately absorb sufficient energy during the fall arrest, the polymeric material may have a hardness of at least 30° IRHD, at least 40° IRHD, ormore specifically at least 50° IRHD. The polymeric material may specifically have a hardness range between 30° and 70° IRHD, or more specifically between 40° and 60° IRHD. The polymeric material may have a compression set value small enough so that it may be reusable beyond a single fall usage. For example, the polymeric material may have a compression set of less than 40%, or more specifically less than 30%. Compression set values may be calculated according to ASTM D395-18. The polymeric material may comprise, consist essentially of, or consist of silicone. Alternatively, the polymeric material may comprise, consist essentially of, or consist of a thermoplastic or thermoset elastomer. The polymeric material may be a polymer composite. As one example, the polymeric material may be a silicone rubber having a wall thickness of 3 millimeters. More generally, the thickness and material properties of the compressible tube or pad may specifically be selected in order to meet the energy capacity requirement of ANSI Z359.14- 21 clauses 3.4 & 4.4. In place of a polymeric material, the compressible material described in the present disclosure may instead be a suitable non-polymeric compressible material.

[0037] Rather than relying on a rigid internal lifeline hub and a compressible polymeric pad or tubing component, an aspect of the present disclosure provides a flexible lifeline hub that may itself absorb some of the initial peak forces experienced by a user when the reserve line is paid out. In other words, the circular lifeline hub itself may undergo a change in shape, rather than any component attached to its surface or the surface of the reserve line. In such cases, the surface of the lifeline hub around which the reserve line is wound may be formed of an elastic, flexible material, such as a polymeric material. When the reserve line is paid out, the deformation of the lifeline hub surface may dampen the peak forces experienced by the user as the fall arrest mechanism activates.

[0038] FIG. 9 is a flowchart depicting a method 900 of arresting a fall of a user. At 902, a housing may be provided having a lifeline therein, wherein the housing is connected to a structure and the lifeline is connected to the user. At 904, a portion of the lifeline may be paid out from the housing while retaining a reserve portion of the lifeline in the housing during a normal operating condition. A polymeric tube, such as a compressible polymeric tube, may enclose at least part of the reserve portion of the lifeline. At 906, the reserve portion may be paid out from the housing during a fall operating condition. At 908, an arrest mechanism may be activated to apply a braking force to the lifeline based on paying out the retained portion. When the arrestmechanism is activated, the polymeric tube may function to absorb some of the peak forces that would otherwise be experienced by a user. The method can utilize and incorporate any of the aspects described herein, including those directed to the use of a polymeric pad.

[0039] FIG. 10 is a graphical depiction of experimental results comparing the energy capacity of a fall limiting device having a metal reserve line without a polymeric compressible material (dotted line) and a fall limiting device having a polymeric (here, silicone) compressible tube covering the metal reserve line (solid line). The experimental test was conducted according to the procedures outlined in ANSI Z359.14-21. As can be seen in the experimental results, the introduction of the polymeric tubing substantially reduced the peak forces experienced (i.e., the initial spike) from roughly 8 kN to about 6 kN.

[0040] While the disclosure has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit of the embodiments. Thus, it is intended that the present disclosure cover the modifications and variations of this disclosure provided they come within the scope of the appended claims and their equivalents.

Claims

CLAIMS1. A fall limiting device, comprising:• a housing having a lifeline therein;• a fall arrest mechanism configured to apply a braking force to the lifeline based on motion of the lifeline; and• a compressible tube enclosing at least part of a reserve portion of the lifeline, wherein the reserve portion of the lifeline is configured to be retained in the housing during a first operating condition, wherein the fall limiting device is configured to allow at least a portion of the reserve portion of the lifeline to extend from the housing during a second operating condition, wherein the fall arrest mechanism is configured to apply the braking force to the lifeline during the second operating condition.

2. The device of claim 1, wherein the reserve portion of the lifeline is substantially retained around a drum hub within the housing during the first operating condition, and wherein at least a portion of the compressible tube is configured to undergo compression between the lifeline and the drum hub when the braking force is applied during the second operating condition.

3. The device of claim 2, wherein the fall limiting device is configured so that the compression of the compressible tube continuously occurs as the retained portion of the lifeline is extended from the housing during a second operating condition.

4. The device of claim 2, wherein the fall arrest mechanism is configured to apply the braking force based on the rotational speed of the drum.

5. The device of any one of the preceding claims, wherein the first operating condition is a non-fall operating condition and wherein the second operating condition is a fall operating condition.

6. The device of any one of the preceding claims, wherein the compressible tube has a tube wall thickness of at least 1.5 millimeters.

7. The device of any one of the preceding claims, wherein the compressible tube is formed of a material having a hardness between 30° and 70° IRHD.

8. The device of any one of the preceding claims, wherein the compressible tube is formed of a material having a hardness between 40° and 60° IRHD.

9. The device of any one of the preceding claims, wherein the compressible tube is a polymeric tube.

10. The device of any one of the preceding claims, wherein the compressible tube comprises silicone.

11. The device of any one of the preceding claims, wherein the compressible tube encloses at least half of the total length of the reserve portion of the lifeline.

12. The device of any one of the preceding claims, wherein the compressible tube encloses substantially all of the total length of the reserve portion of the lifeline.

13. The device of any one of the preceding claims, wherein a reserve retainer is attached to the lifeline, the reserve retainer being configured to retain a portion of the lifeline in the housing during a first operating condition.

14. The device of any one of the preceding claims, wherein the lifeline comprises a synthetic material comprising a plurality of strands, wherein the reserve retainer is attached between strands of the lifeline.

15. The device of one of the preceding claims, wherein the housing comprises an attachment piece configured to connect the fall limiting device directly or indirectly to a structure.

16. The device of one of the preceding claims, wherein the lifeline comprises a clip a hook, a loop, a carabiner or a ring configured for connecting the lifeline to a harness of a user.

17. The device of one of the preceding claims, wherein the fall arrest mechanism is configured to apply the braking force any time the second operating condition occurs, regardless of an amount of lifeline paid out from the housing prior to initiation of the second operating condition.

18. A lifeline for a fall limiting device: a lifeline cable having a first end configured to connect to a safety harness and a second end configured to attach to an internal drum hub of a fall limiting device housing, wherein a reserve portion of the lifeline is at least partially enclosed by polymeric tube, and wherein the reserve portion is positioned on the second end of the lifeline.

19. The lifeline of claim 18, further comprising: a reserve retainer, wherein the reserve retainer is positioned on the lifeline and configured to interact with the fall limiting device housing to retain the reserve portion of the lifeline.

20. The lifeline of claim 18 or 19, wherein the polymeric tube encloses substantially all of the total length of the reserve portion of the lifeline.

21. The lifeline of one of claims 18-20, wherein the polymeric tube comprises silicone.

22. A fall limiting device, comprising:• a housing having an internal drum hub with a cylindrical hub surface;• a lifeline at least partially wrapped around the drum hub;• a polymeric pad at least partially positioned between the lifeline and the cylindricalhub surface; and• a fall arrest mechanism configured to apply a braking force to the drum hub based on motion of the lifeline, wherein the polymeric pad is configured to undergo compression between the lifeline and the drum hub when the braking force is applied.

23. The device of claim 22, wherein the polymeric pad is adhesively affixed to the cylindrical hub surface.

24. The device of claim 22, wherein the polymeric pad includes an aperture configured to provide access to the cylindrical hub surface.

25. The device of one of claims 22-24, wherein the polymeric pad has a thickness of at least 1.5 millimeters.

26. A method of arresting a fall of a user, comprising:• providing a housing having a lifeline therein, wherein the housing is connected to a structure and the lifeline is connected to the user;• paying out a portion of the lifeline from the housing while retaining a reserve portion of the lifeline in the housing during a normal operating condition, wherein a polymeric tube encloses at least part of the reserve portion of the lifeline;• paying out the reserve portion from the housing during a fall operating condition; and• activating an arrest mechanism to apply a braking force to the lifeline based on paying out the retained portion.

27. The method of claim 26, wherein the polymeric tube is configured to undergo compression when the braking force is applied during a fall operating condition to reduce a peak force experienced by the user.

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