System and method for absorbing energy of a fall reflex

Abstract

Systems and methods for a fall limiting device are provided. An example apparatus includes a housing having a lifeline therein and a fall prevention mechanism configured to apply a braking force to the lifeline based on movement of the lifeline. A polymer tube enclosing at least a portion of a reserved portion of the lifeline may be configured to remain in the housing during a first normal operating condition. The fall limiting device may be configured to allow the reserved portion of the lifeline to extend from the housing during a second fall operating condition, wherein the fall protection mechanism is configured to apply the braking force to the lifeline during the second operating condition. The polymeric tube may be used to absorb the braking force applied to the lifeline in order to reduce the peak force experienced by the user.

Description

Cross-references to related applications

[0001] This application claims priority to GB application No. 2310958.0, filed on July 13, 2023, which is incorporated herein by reference in its entirety for all purposes. Background Technology

[0002] In high-safety applications, such as working on building rooftops, fall limiting devices such as self-retracting tethers (SRLs) are typically used to provide a safe connection between the user wearing the tether and the structure or safety line. In normal operation, the fall limiting device allows the lifeline to exit from the fall limiting device, allowing the user a certain degree of freedom of movement. In the event of a fall, the fall limiting device may include mechanisms to prevent the fall while maintaining the integrity of the fall limiting device and the lifeline to avoid or limit injury. Such fall protection mechanisms are used to limit the forces acting on the user's body during a fall by slowly bringing the user to a stop. If the peak force experienced by the user exceeds a certain threshold, the user may be injured. Summary of the Invention

[0003] This document provides systems and methods for fall arresters having a pre-installed line that contacts a compressible component, such as a polymer material. When the fall arrester applies braking force to the lifeline, the compressible component may undergo compression to help reduce the braking force experienced by the falling user. In some aspects, the compressible component may take the form of a polymer tube surrounding a portion of the pre-installed line, or a polymer pad positioned below the pre-installed line (e.g., on a spool around which the lifeline is wound). By adding this additional compressible component, safety standards can be maintained without having to adjust the fall arrester or extend the length of the pre-installed line.

[0004] In one aspect, this disclosure provides a fall limiting device. The fall limiting device may include: a housing having a lifeline therein; a fall arrestor configured to apply a braking force to the lifeline based on movement of the lifeline; and a compressible tube enclosing at least a portion of a reserved portion of the lifeline. The reserved portion of the lifeline may be configured to remain within the housing during a first operating condition. The fall limiting device may be configured to allow at least a portion of the reserved portion of the lifeline to extend from the housing during a second operating condition, wherein the fall arrestor is configured to apply a braking force to the lifeline during the second operating condition.

[0005] In another aspect, this 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 swivel hub of a fall limiting device housing, wherein a reserved portion of the lifeline is at least partially encased in a polymer tube, and wherein the reserved portion is positioned at the second end of the lifeline. In one embodiment, the polymer tube is compressible.

[0006] In one aspect, this disclosure provides another fall limiting device. The fall limiting device may include: a housing having an inner swivel hub with a cylindrical hub surface; a lifeline at least partially wound around the swivel hub; a polymer 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 swivel hub based on the movement of the lifeline. The polymer pad may be configured to undergo compression between the lifeline and the swivel hub when the braking force is applied.

[0007] In another aspect, this disclosure provides a method for preventing a user from falling. 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; releasing a portion of the lifeline from the housing during normal operating conditions while retaining a reserved portion of the lifeline within the housing, wherein a polymer tube encapsulates at least a portion of the reserved portion of the lifeline; releasing the reserved portion from the housing during fall operating conditions; and activating a stopping mechanism to apply braking force to the lifeline based on the release of the reserved portion. In one embodiment, the polymer tube is compressible. Attached Figure Description

[0008] Figure 1 It is a diagram depicting a safety line system that secures personnel performing construction work on top of the structure.

[0009] Figure 2 It is a diagram depicting a fall restraint device.

[0010] Figure 3A This is a diagram depicting a fall limiting device operating under the first normal operating conditions.

[0011] Figure 3B This is a diagram depicting a fall limiting device operating during the second fall operation condition.

[0012] Figure 4 This is a diagram depicting a fall restraint device, in which a pre-installed portion of the lifeline extends from the outer casing of the fall restraint device. The pre-installed portion of the lifeline includes a polymer tube.

[0013] Figure 5It is a diagram depicting a lifeline assembly of a polymer tube with a reserved portion of an encapsulated lifeline.

[0014] Figure 6 This is a diagram depicting a fall restraint device with a polymer pad partially wrapped around the cylindrical hub surface of the inner rotary hub. For clarity, the polymer pad is shown in an unfolded, partially detached form.

[0015] Figure 7 It is a diagram depicting a section of a fall-limiting device with a polymer pad that is partially wrapped around the cylindrical hub surface of the inner rotary hub.

[0016] Figure 8 It is a polymer pad that is configured to partially wrap around the cylindrical hub surface of the inner rotary hub of the fall limiting device.

[0017] Figure 9 It is a flowchart depicting a method to prevent a user from falling.

[0018] Figure 10 This is a graphical depiction of the experimental results comparing the energy capacity of a fall limiter with a metal pre-reserved wire (dashed line) and a fall limiter with a polymer tube covering the metal pre-reserved wire (solid line). Detailed Implementation

[0019] Fall limiting devices such as self-retracting tethers (SRLs) can be designed to extend (release) a portion of the lifeline from its housing during normal operation to allow the attached user (e.g., a sling-wearing technician) a degree of freedom of movement while retaining a portion of the lifeline within the housing. Fall limiting devices can utilize fall arrest mechanisms (i.e., braking mechanisms) that are activated based on increased movement of the lifeline, such as centrifugal force at the drum holding the lifeline caused by a falling user. However, many fall arrest mechanisms require a minimum length of lifeline within the housing (e.g., wound around the drum) to function correctly during a fall event. Therefore, if a fall limiting device allows the entire lifeline to be extended, the fall arrest mechanism may not be activated. By retaining a pre-existing portion of the lifeline within the housing during normal operation, but allowing the pre-existing portion of the lifeline to be extended or released during fall conditions, the fall arrest mechanism can be properly activated, thus preventing or mitigating injury to the user.

[0020] Because the fall arrestor must rely solely on the finite length of the slack line once the rest of the lifeline is deployed, bringing a falling user to a resting state without subjecting them to dangerous forces can be challenging. One option for limiting the peak force experienced by a user during a fall arrest is to reduce the average force provided by the fall arrestor. However, if the average force of the fall arrestor is reduced, it may be necessary to increase the stopping distance. Unfortunately, in many cases, increasing the stopping distance is not an option, and some safety standards specifically require a maximum stopping distance (e.g., one meter).

[0021] This disclosure provides systems and methods for overcoming the aforementioned challenges by relying on deformable materials to absorb some of the peak forces applied to the spool line by the fall arrestor. In some aspects, the spool portion of the lifeline may be substantially retained around the 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 braking force is applied (i.e., during fall arrest). This compression can help reduce the peak forces experienced by the user connected to the lifeline. In one example, the deformable material may be positioned between the spool line and the drum hub, such as a polymer pad on the surface of the drum of a fall arrestor. In another example, the deformable material serves as a shell encapsulating the spool line itself. For example It takes the form of a polymer shell. By deforming the added material, the peak force experienced by the user during a fall can be significantly reduced.

[0022] Although this disclosure is primarily discussed in relation to applications involving the prevention of falls by users wearing harnesses, it should be readily understood that other uses of the systems and methods described herein are possible. For example, the teachings described herein can be applied more generally to any application involving fall arrest mechanisms and associated rotating drums, including, for example, the transport or movement of sensitive equipment that needs to be securely secured to prevent falls.

[0023] Figure 1 A safety line system is depicted to secure personnel performing construction work on top of a structure. The system includes a first rigid member 102, which takes the form of a vertical column extending from a horizontal member 104 of the structure. The first rigid member 102 can be connected to the horizontal member 104 via mechanical means such as bolts, screws, adhesives, or other methods. A safety line 106 is connected to the first rigid member 102 and extends horizontally between the first rigid member 102 and a second rigid member (not shown). A user 108 performing the construction work wears a sling 110, which is connected to the safety line 106 via a tether 112 having a connector 114. Figure 1The safety line arrangement allows the user 108 to traverse the structure at any point within the tether length of the safety line. A fall limiting device (not shown) may replace connector 114 and be connected to tether 112 or directly to sling 110 of user 108. According to the example described herein, the fall limiting device may be configured to release some of the lifeline during normal operation to allow user 108 a certain degree of freedom of movement, while a reserved portion of the lifeline may remain within the fall limiting device during the first normal operating conditions.

[0024] Figure 2 An exemplary fall restraint device 200 is depicted. The fall restraint device 200 may include a connecting device 202 configured to attach to an object to be secured, such as a sling worn by a user. The connecting device 202 may be attached to a lifeline (received within the depicted housing 204 and therefore generally not visible), which, when not in use, may be wound around a spool 212 housed within the housing 204 of the fall restraint device 200, as shown. As will be further described, a compressible component (not depicted) may be at least partially inserted between the spool and at least a portion of the lifeline. During a fall event, at least a portion of the compressible component may be effectively compressed (i.e., compressed) between the spool 212 and the lifeline to mitigate the peak force experienced by the user connected to the connecting device 202. The lifeline may take various forms, including, for example, a single metal wire, a braided metal wire, a single synthetic wire, a synthetic wire made of multiple strands, or a natural material wire made of multiple strands. The attachment 206 can be used to secure the housing 204 to the supported fixed structure. The attachment 206 can take various forms, including hooks, clips, rings, loops, or hook-and-loop fasteners.

[0025] Figure 3A A diagram depicts a fall-limiting device 300 operating under first normal operating conditions. The fall-limiting device 300 is shown connected to a structure 330 via an attachment 306. The structure 330 can take various forms, including walls, wires (such as...). Figure 1 The diagram depicts a horizontal structure (e.g., a floor) or a roof. A user 308 is also shown connected to a fall restraint device 300 via a lifeline 310, a portion of the lifeline's length wound around a lifeline spool 312 within the housing 314 of the fall restraint device 300. With this arrangement, when performing a work task, the user 308 can connect to the lifeline 310 of the fall restraint device 300 via a connecting device such as a hook, clamp, loop, or swivel. The lifeline spool 312 may be biased by a spring or other mechanism that winds up the released lifeline 310 when the user 308 is not applying tension.

[0026] Fall arrestor 340 may also be housed within housing 314 and configured to stop lifeline 310 in the event of an accident (e.g., a fall) by limiting the rotation of the drum and thus limiting the movement of lifeline 310. Fall arrestor 340 may operate alone or in combination with other fall arrestors (e.g., an inline energy absorber connected between lifeline 310 and user 308, or between attachment 306 and structure 330) to stop and mitigate injury to user 308 during a fall. Fall arrestor 340 may deploy based on the movement of lifeline 310 (e.g., acceleration, centrifugal force induced by rapid release). In some instances, fall arrestor 340 may deploy based on the force experienced when lifeline 310 is released at a rate exceeding a threshold rate. Fall arrestor 340 may be attached to lifeline drum 312. For example, the fall arrestor 340 may include one or more pawls that rotate from a retracted position to an engaged position based on centrifugal force provided by the rotation of the lifeline drum 312 when the lifeline 310 is deployed at a high rate of change (such as during fall conditions). Additional details regarding the fall arrestor can be found, for example, in U.S. Patent Application No. 17 / 710,365, filed March 31, 2022, the entire contents of which are incorporated herein by reference.

[0027] In a first normal operating condition, such as when user 308 is safely performing a task (i.e., not falling), fall limiting device 300 may be configured to allow a portion of lifeline 310 to be released from the housing of fall limiting device 300 to provide user 308 with some degrees of freedom of movement. In this way, user 308 can move around the site without the fall limiting device 300 substantially impeding their movement. Therefore, the fall arrest mechanism 340 of device 300 can be in a disengaged state during this first normal operation. Furthermore, during such a first normal operation, any reserved portion of lifeline 310 may be retained within housing 314. Retaining the reserved portion of lifeline 310 during the first normal operating condition helps ensure that a sufficient amount of lifeline 310 (e.g., one meter long) remains within housing 314 to cause sufficient rotation of lifeline spool 312, thereby engaging fall arrest mechanism 340 during a second fall operating condition.

[0028] Figure 3BA diagram depicts the operation of a fall restraint device 300 during a second fall operation condition. As shown, the user 308 remains connected to the fall restraint device 300 via a lifeline 310, which is still connected to the structure 330 via an attachment 306. As indicated by the arrow in this example, the user 308 is falling in a downward direction away from the fall restraint device 300. In response, the fall restraint device 300 transitions from a normal first operating condition to a second fall operation condition (e.g., fall condition, abnormal condition, alarm condition, warning condition, emergency condition). In some aspects, the fall restraint device 300 entering a second fall operation condition may cause various actions beyond simply preventing the user 308 from falling. For example, an alarm condition in which an audible alarm is issued from the fall restraint device 300 or a signal is transmitted from an antenna on the fall restraint device 300 (e.g., to a server tracking operational data (e.g., to monitor safety protocol compliance)) may alert the relevant authorities to initiate the dispatch of assistance.

[0029] As shown in the figure, in the second fall condition, a portion of the reserved portion of the lifeline 310 (i.e., the portion of the lifeline 310 that remains substantially within the housing during the first normal operating condition) extends outside the housing of the fall limiting device 300. The fall limiting device 300 may be specifically configured to allow only a portion of the reserved portion of the lifeline 310 to extend from the housing 314 during such a second fall operating condition. Similarly, the fall arrestor 340 may be configured to apply braking force to the lifeline 310 during the second fall operating condition. As further described herein, a compressible tube 320 (e.g., a polymer tube) may enclose at least a portion of the reserved portion of the lifeline (i.e., the portion that remains within the housing 314 during the first normal operating condition) to suppress peak forces experienced by the user 308 when the fall arrestor 340 is activated. In other words, when the reserved line is released, the compressible tube 320 surrounding the reserved line can compress to absorb some of the initial peak forces experienced by the user 308. By incorporating the compressible tube 320, users can more comfortably reach a safe resting position during a fall.

[0030] In some instances, a reserved retainer 316 may be attached to the lifeline 310 to limit the amount of lifeline 310 that can be released. For example, the reserved retainer 316 may be attached at a specific point on the lifeline 310, such as between the strands of the lifeline 310 in the case where the lifeline 310 is formed of a composite material comprising multiple strands. When the point on the lifeline 310 with the reserved retainer 316 reaches a threshold of the fall limiting device 300 at the lifeline stop (not depicted) (e.g., a slot wide enough for the lifeline 310 to pass through but through which the wider reserved retainer 316 does not pass), the interaction between the reserved retainer 316 and the lifeline stop prevents further release of the lifeline 310 from the fall limiting device 300 during the first normal operating conditions. Therefore, the reserved retainer can be used to retain the reserved portion of the lifeline 310 within the housing 312 unless the user 308 experiences a fall, in which case the reserved retainer may no longer be used to retain the reserved line within the housing 312 (e.g., the lifeline stop is disconnected from or detached from the housing). It should also be understood that other alternative forms of reserved retainers for retaining the reserved portion of the lifeline are possible.

[0031] Figure 4 Another fall limiting device 400 is depicted, wherein a reserved portion of the lifeline 410 extends from the housing 414 of the fall limiting device 400. As shown, a compressible tube 420 can substantially cover all reserved portions of the lifeline 410 extending from the lifeline reel 412 to the reserved retainer 416. The compressible tube 420 can be configured to be compressed during activation of the fall arrest mechanism. In other words, the portion of the compressible tube 420 subsequently located between the reel 412 and the lifeline 410 can be effectively compressed between them during fall arrest. Although the compressible tube 420 is depicted as substantially covering all reserved lines, the compressible tube 420 can alternatively cover only a portion of the reserved lines. For example, the compressible tube 420 can cover at least a quarter of the reserved lines, or more specifically, at least half of the reserved lines. The compressible tube 420 may be positioned from the spool end of the pre-reserved line, or alternatively from the user end of the pre-reserved line (i.e., covering only half of the pre-reserved line starting from the pre-reserved retainer 416 and upwards along the pre-reserved line). Furthermore, although the compressible tube 420 is generally described as a coating or tubing on the pre-reserved portion of the lifeline herein, it should be understood that other configurations are possible. For example, the pre-reserved line may be a separate line connected to the lifeline 410, and the compressible tube 420 may be replaced by a solid polymer compressible pre-reserved line (i.e., not a tubing).

[0032] Figure 5A lifeline assembly 500 of a fall restraint device is depicted, having a compressible tube 520 that encloses at least a portion of a reserved section of a lifeline 510. As shown, the reserved section of the lifeline 510 can be positioned between a reserved retainer 516 and a lifeline connector 522. The lifeline connector 522 can be configured to securely attach the lifeline assembly 500 to a lifeline hub or other internal component of the fall restraint device. The compressible tube 520 can be specifically configured to absorb some of the peak forces experienced by the user of the fall restraint device during a fall. The compressible tube 520 can have a thickness that allows the fall restraint device to safely allow the user to rest. For example, the wall thickness (i.e., the radius of the compressible tube 520 minus the radius of the reserved line 510) can be at least 1 mm, at least 1.5 mm, at least 2 mm, or specifically about 3 mm. The compressible tube 520 may be located solely on the lifeline 510, and the lifeline 510 may otherwise be free of any polymer tubing.

[0033] Figure 6 A fall restraint device 600 is depicted, wherein a polymer pad 650 is partially wound around the cylindrical hub surface of a lifeline hub 612 housed within a housing 610. For clarity, the polymer pad 650 is shown in an unfolded, partially detached form. When fully assembled, the polymer pad 650 can be inserted between the hub surface and the lifeline 610 wound around the hub 612. In this way, by compression to absorb the peak forces associated with a fall, the polymer pad 650 can function in a manner similar to the compressible tube previously described herein.

[0034] Figure 7 A cross-sectional view of a fall restraint device 700 is depicted, in which a polymer component 750 (e.g., a pad) is partially wrapped around the cylindrical hub surface of a lifeline hub 716. As shown, the polymer pad 750 may include a first hole 752 configured to allow a tool to access a hub fastener configured to secure the lifeline 710 to the lifeline hub 716. A second hole 754 may provide an access point for the lifeline 710 to pass through the polymer pad 750 and securely attach to the lifeline hub 716. By including holes only where necessary, the polymer pad can advantageously cover substantially the entire surface of the lifeline hub 716. However, instead of including access holes, the polymer pad may instead cover only a portion 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 to the access and attachment points.

[0035] Figure 8A polymer pad 850 is depicted, configured to partially wrap around the cylindrical hub surface of the inner lifeline hub of a fall restraint device. The polymer pad 850 may include a first hole 852 and a second hole 854. An adhesive component may be included on the inner surface 856 of the polymer pad 850 to attach the polymer pad 850 to the surface of the inner lifeline hub. The adhesive component may be an integrated portion of the inner surface 856, or alternatively, it may be physically separated from it (e.g., double-sided adhesive tape). Alternatively, other attachment techniques may be used to secure the polymer pad 850 to the lifeline hub. For example, the polymer pad 850 may be directly overmolded or otherwise integrated directly with the cylindrical hub surface of the inner lifeline hub. Similar to the polymer tubing previously described herein, the polymer pad 850 may have a suitable thickness to compress and absorb a sufficient amount of peak energy associated with fall protection. For example, the wall thickness of the polymer pad 850 may be at least 1 mm, at least 1.5 mm, at least 2 mm, or specifically about 3 mm. The thickness of the polymer pad 850 can depend on the material it is made of.

[0036] Polymer materials can be used in the compressible tubes and pads described herein and can be specifically selected to provide sufficient force absorption to the pre-reserved line during activation of the fall arrestor. Therefore, polymer materials can be specifically selected to have sufficient thickness and suitable material properties. For example, as discussed, polymer materials can have a wall thickness of at least 1 mm, at least 1.5 mm, or more specifically at least 2 mm. However, if the polymer material exceeds a certain wall thickness, it may occupy excessive volume within the housing of the fall arrestor, potentially causing volume problems. Therefore, polymer materials can have a wall thickness of less than 10 mm, or more specifically less than 5 mm. The polymer material can have a sufficiently low stiffness value such that it provides sufficient compression when compressed between the drum hub and the pre-reserved portion of the lifeline. For example, polymer materials can have a stiffness of less than 80°IRHD, less than 70°IRHD, or more specifically about 60°IRHD. Similarly, to avoid being too soft to absorb sufficient energy during a fall, the polymer material may have a hardness of at least 30° IRHD, at least 40° IRHD, or more specifically at least 50° IRHD. Specifically, the polymer material may have a hardness range between 30° and 70° IRHD, or more specifically between 40° and 60° IRHD. The polymer material may have a sufficiently low compression set value to be reusable after a single drop. For example, the polymer material may have a compression set of less than 40%, or more specifically less than 30%. The compression set value may be calculated according to ASTM D395-18. The polymer material may contain silicone, be substantially composed of silicone, or be composed of silicone. Alternatively, the polymer material may contain thermoplastic or thermosetting elastomers, be substantially composed of thermoplastic or thermosetting elastomers, or be composed of thermoplastic or thermosetting elastomers. The polymer material may be a polymer composite. As an example, the polymer material may be silicone rubber with a wall thickness of 3 mm. More generally, the thickness and material properties of the compressible tube or pad can be specifically selected to meet the energy capacity requirements of Clauses 3.4 and 4.4 of ANSI Z 359.14-21. Instead of polymeric materials, the compressible materials described in this disclosure can alternatively be suitable non-polymeric compressible materials.

[0037] One aspect of this disclosure provides a flexible lifeline hub that absorbs some of the initial peak forces experienced by the user when the pre-deployed line is released, rather than relying on a rigid internal lifeline hub and compressible polymer pads or tubular components. In other words, the circular lifeline hub itself can undergo shape deformation, rather than any component attached to its surface or the surface of the pre-deployed line. In such cases, the surface around which the pre-deployed line is wound around the lifeline hub can be formed of an elastic, flexible material such as a polymer. When the pre-deployed line is released, the deformation of the lifeline hub surface can suppress the peak forces experienced by the user when the fall arrestor is activated.

[0038] Figure 9 This is a flowchart depicting a method 900 for preventing a user from falling. At 902, a housing having a lifeline is provided, wherein the housing is connected to a structure and the lifeline is connected to the user. At 904, during normal operating conditions, a portion of the lifeline is released from the housing while a reserved portion of the lifeline is retained within the housing. A polymer tube, such as a compressible polymer tube, can enclose at least a portion of the reserved portion of the lifeline. At 906, the reserved portion can be released from the housing during fall operating conditions. At 908, a stopping mechanism can be activated based on the release of the reserved portion to apply braking force to the lifeline. When the stopping mechanism is activated, the polymer tube can be used to absorb some of the peak forces that the user would otherwise experience. This method can utilize and combine any aspects described herein, including those involving the use of a polymer pad.

[0039] Figure 10 This is a graphical depiction of experimental results comparing the energy capacity of a drop limiter with a metal pre-reserved wire without polymer compressible material (dashed line) and a drop limiter with a polymer (here, silicone) compressible tube covering the metal pre-reserved wire (solid line). The experimental tests were conducted according to the procedures outlined in ANSI Z359.14-21. As can be seen from the experimental results, the introduction of the polymer tube substantially reduces the peak force experienced (i.e., the initial peak) from approximately 8 kN to approximately 6 kN.

[0040] Although this disclosure has been described in detail and with reference to specific embodiments thereof, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the embodiments. Therefore, this disclosure is intended to cover modifications and alterations to this disclosure, provided that they fall within the scope of the appended claims and their equivalents.

Claims

1. A fall-limiting device, the fall-limiting device comprising: An outer casing, wherein a lifeline is provided; A fall arrestor mechanism configured to apply braking force to the lifeline based on the movement of the lifeline; and A compressible tube encloses at least a portion of a reserved portion of the lifeline, wherein the reserved portion of the lifeline is configured to remain within the housing during a first operating condition. The fall limiting device is configured to allow at least a portion of the reserved portion of the lifeline to extend from the housing during a second operating condition, and the fall arrestor is configured to apply the braking force to the lifeline during the second operating condition.

2. The apparatus of claim 1, wherein the reserved portion of the lifeline remains substantially within the housing around the drum hub 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 apparatus of claim 2, wherein the fall limiting device is configured such that compression of the compressible tube occurs continuously when the retained portion of the lifeline extends from the housing during a second operating condition.

4. The apparatus of claim 2, wherein the fall arrestor is configured to apply the braking force based on the rotational speed of the roller.

5. The apparatus as claimed in any 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 as claimed in any of the preceding claims, wherein the compressible tube has a wall thickness of at least 1.5 mm.

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

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

9. The device as claimed in any of the preceding claims, wherein the compressible tube is a polymer tube.

10. The device as claimed in any of the preceding claims, wherein the compressible tube comprises silicone.

11. The device as claimed in any of the preceding claims, wherein the compressible tube encloses at least half of the total length of the reserved portion of the lifeline.

12. The device as claimed in any of the preceding claims, wherein the compressible tube encloses substantially the entire total length of the reserved portion of the lifeline.

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

14. The apparatus of any of the preceding claims, wherein the lifeline comprises a synthetic material having multiple strands, and wherein the reserved retainer is attached between the strands of the lifeline.

15. The device as claimed in any of the preceding claims, wherein the housing includes an attachment configured to directly or indirectly connect the fall limiting device to the structure.

16. The device as claimed in any of the preceding claims, wherein the lifeline comprises a clip, hook, loop, hook-and-loop or ring, the clip, hook, loop, hook-and-loop or ring being configured to attach the lifeline to a user's harness.

17. The device as claimed in any of the preceding claims, wherein the fall arrestor is configured to apply the braking force at any time the second operating condition occurs, regardless of the amount of lifeline released from the housing before the second operating condition begins.

18. A lifeline for a fall restraint 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 swivel hub of a fall limiting device housing, wherein a reserved portion of the lifeline is at least partially encased in a polymer tube, and wherein the reserved portion is positioned on the second end of the lifeline.

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

20. The lifeline of claim 18 or 19, wherein the polymer tube encloses substantially the entire total length of the reserved portion of the lifeline.

21. The lifeline of any one of claims 18 to 20, wherein the polymer tube comprises organosilicon.

22. A fall limiting device, the fall limiting device comprising: The housing has an internal rotary hub with a cylindrical hub surface; A lifeline, which is at least partially wrapped around the drum hub; A polymer pad, the polymer pad being at least partially positioned between the lifeline and the cylindrical hub surface; and A fall arrestor configured to apply a braking force to the swivel hub based on the movement of the lifeline, wherein the polymer pad is configured to be compressed between the lifeline and the swivel hub when the braking force is applied.

23. The apparatus of claim 22, wherein the polymer pad is adhesively attached to the cylindrical hub surface.

24. The apparatus of claim 22, wherein the polymer pad includes holes configured to provide access to the cylindrical hub surface.

25. The device of any one of claims 22 to 24, wherein the polymer pad has a thickness of at least 1.5 mm.

26. A method for preventing a user from falling, the method comprising: A housing is provided in which a lifeline is included, wherein the housing is connected to a structure and the lifeline is connected to the user; During normal operating conditions, a portion of the lifeline is released from the housing while a reserved portion of the lifeline is retained within the housing, wherein a polymer tube encapsulates at least a portion of the reserved portion of the lifeline; The reserved portion is released from the outer casing during drop operation conditions; as well as The release of the reserved portion activates the stopping mechanism to apply braking force to the lifeline.

27. The method of claim 26, wherein the polymer tube is configured to be compressed when the braking force is applied during drop operation conditions to reduce the peak force experienced by the user.

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