Braking device configured to exhibit low-pass mechanical filtering

Abstract

A braking device such as for use in a fall-protection apparatus such as a self-retracting lifeline. The braking device may include a velocity -actuated pawl that is configured to be a high-moment-of-inertia pawl, e.g. by equipping the pawl with a ballast element. The device may include an inertia disk that is a damped, e.g. an actively damped, inertia disk. The velocity-actuated pawl may be biased toward a disengaged position, and the inertia disk may be biased toward a home position, by way of a co-biasing arrangement using the same biasing element.

Description

[0001] BRAKING DEVICE CONFIGURED TO EXHIBIT LOW-PASS MECHANICAL FILTERING

[0002] Background

[0003] Fall-protection apparatus such as self-retracting lifelines have often found use in applications such as building construction and the like.

[0004] Summary

[0005] In broad summary, herein are disclosed braking devices such as for use in a fall-protection apparatus such as a self-retracting lifeline. In one aspect, such a braking device may comprise at least one velocity-actuated pawl that is on a pawl-support plate and that can be actuated between a disengaged position and an engaged position, with the pawl being biased toward the disengaged position. In another aspect, such a braking device may comprise an inertia disk that is rotatable with respect to the pawl-support plate through a predetermined range between a home position and an activated position, with the inertia disk being biased toward the home position. In another aspect, the inertia disk and the at least one pawl can be configured so that when the inertia disk is in the activated position, the velocity -actuated pawl can be actuated toward the engaged position by a rotational velocity that is lower than a rotational velocity required to actuate the pawl when the inertia disk is in the home position.

[0006] In one aspect, the at least one velocity -actuated pawl may be configured so that the pawl is a high- moment-of-inertia pawl; in one particular aspect, this may be facilitated by equipping the pawl with a ballast element. In one aspect, the inertia disk may be a damped inertia disk; in one particular aspect, the inertia disk may be an actively damped inertia disk. In one aspect, the at least one velocity -actuated pawl may be biased toward its disengaged position, and the inertia disk may be biased toward its home position, by way of a co-biasing arrangement using the same biasing element.

[0007] These and other aspects will be apparent from the detailed description below. In no event, however, should this broad summary be construed to limit the claimable subject matter, whether such subject matter is presented in claims in the application as initially filed or in claims that are amended or otherwise presented in prosecution.

[0008] Brief Description of the Drawings

[0009] Fig. 1 is a perspective view of an exemplary fall-protection apparatus.

[0010] Fig. 2 is a perspective partially-exploded view of various components of an exemplary fallprotection apparatus.

[0011] Fig. 3 is an isolated perspective view of various components of an exemplary fall-protection apparatus.

[0012] Fig. 4 is an isolated perspective view of the pawl-support plate shown in Fig. 3, along with an exemplary inertia disk and a pair of exemplary velocity -actuated pawls.

[0013] Fig. 5 is a partially exploded perspective view of the exemplary components shown in Fig. 4.

[0014] Fig. 6 is a plan view of the exemplary components shown in Fig. 4, with an exemplary inertia disk shown in a home position and with exemplary velocity -actuated pawls shown in disengaged positions. Fig. 7 is a plan view of the exemplary components shown in Fig. 6, with the exemplary inertia disk shown as having moved to an activated position and with the exemplary velocity -actuated pawls remaining in disengaged positions.

[0015] Fig. 8 is a plan view of the exemplary components shown in Fig. 7, with the exemplary inertia disk in the activated position and with the exemplary velocity -actuated pawls shown as having moved toward engaged positions.

[0016] Fig. 9 is an isolated perspective view of an exemplary inertia disk.

[0017] Figs. 10a and 10b are plan and perspective views of an exemplary velocity -actuated, high-moment- of-inertia pawl.

[0018] Like reference numbers in the various figures indicate like elements. Some elements may be present in identical or equivalent multiples; in such cases only one or more representative elements may be designated by a reference number but it will be understood that such reference numbers apply to all such identical elements. Although terms such as “first” and “second” may be used in this disclosure, it should be understood that those terms are used in their relative sense only unless otherwise noted. Any use of the term “the” or “a” (e.g., “the” pawl, “the notch”, and so on) will be understood to refer to “at least one”, particularly for items (e.g. such as pawls, notches, biasing magnets, damping magnets, and so on) that may be present in multiples.

[0019] Geometric descriptors are used herein, unless otherwise specified, with reference to a drum 90 and an associated pawl-support plate 70 and items associated therewith, of a fall-protection apparatus as described in detail herein and as shown in exemplary embodiment in Fig. 2. The term “axially” and like terms refer to a direction at least generally parallel to the axis of rotation of the drum, pawl-support plate, and associated items. The term “radial” and like terms refer to a direction that is generally parallel to the radius of the dmm and the pawl-support plate and that is generally perpendicular to the axial direction. The term circumferential and like terms refer to an arcuate direction that exhibits a generally constant radius relative to the axis of rotation of the drum and associated components. The axial, radial, and circumferential directions are indicated (by arrows “a”, “r”, and “c”) in various Figures. The axial arrow “a” as shown in Fig. 3 is positioned so as to indicate the axis of rotation “Ra” of the drum, pawl-support plate, and associated items.

[0020] The direction of rotation of various components (e.g. drum 90, pawl-support plate 70, and associated items) in the instance that drum 90 rotates in the event of a user fall, is denoted as an unwinding direction, signifying that rotation in this direction will cause a safety line 115 to unwind from drum 90. An opposite rotational direction is designated as a winding direction. The unwinding and winding directions are indicated (by arrows “U” and “W”) in various Figures herein. The term “leading” is also used herein and refers to a direction along the unwind direction of rotation; the term “trailing” refers to an opposite direction. The leading and trailing directions are indicated (by arrows as “L” and “T”) in various Figures herein. These terms are used to characterize the relative position and / or orientation of various items that travel along a generally circumferential pathway in the event of the above-described rotation in the unwinding direction. “Leading” refers to a component that, upon such unwinding rotation, passes a stationary reference point before a “trailing” component passes the stationary reference point.

[0021] Terms such as fixing, fixed, fixedly connected, and similar terms, mean that the item in question is attached or otherwise disposed so that it cannot move relative to another entity to which it is fixed, fixedly connected, etc. Such fixing may be direct or indirect. The specific terminology of items being in fixed rotational relation means that the items cannot rotate relative to each other. The designation of an item as integral, and similar terms, denote a configuration in which the item is a part of another entity, has the same composition as the entity, and was manufactured in the same process, at the same time, as the entity An item that is integral with an entity is thus distinguished from an item that is separately made and then is attached to the entity.

[0022] The term “closely abut” and like terms denote entities (e.g. items or regions thereof) that are less than 12 mm apart at their point of closest approach. The term ferromagnetic is defined as comprising a Relative Magnetic Permeability (p / go) of greater than 10 (measured at 20 °C). The term (electrically) conductive is defined as comprising a specific conductance (o) of greater than 10 siemens per meter (measured at 20 °C).

[0023] As used herein as a modifier to a property or attribute, the term “generally”, unless otherwise specifically defined, means that the property or attribute would be readily recognizable by a person of ordinary skill but without requiring a high degree of approximation (e.g., within + / - 20 % for quantifiable properties). The term “substantially”, unless otherwise specifically defined, means to a high degree of approximation (e.g., within + / - 10% for quantifiable properties). The term “essentially” means to a very high degree of approximation (e.g., within plus or minus 2 % for quantifiable properties; it will be understood that the phrase “at least essentially” subsumes the specific case of an “exact” match. However, even an “exact” match, or any other characterization using terms such as e.g. same, equal, identical, uniform, constant, and the like, will be understood to be within the usual tolerances or measuring error applicable to the particular circumstance rather than requiring absolute precision or a perfect match. The term “configured to” and like terms is at least as restrictive as the term “adapted to”, and requires actual design intention to perform the specified function rather than mere physical capability of performing such a function. All references herein to numerical parameters (dimensions, ratios, and so on) are understood to be calculable (unless otherwise noted) by the use of average values derived from a number of measurements of the parameter.

[0024] Detailed Description

[0025] Fall-protection apparatus

[0026] Disclosed herein is a braking device that may be used e.g. in a fall-protection apparatus, by which is meant an apparatus that acts to controllably decelerate a human user of the apparatus in the event of a user fall. By definition, such a fall-protection apparatus, and a braking device thereof, is non-motorized. By this is meant that a safety line of the apparatus is not moved (i.e., extended or retracted from a housing of the apparatus) by way of an electrically powered motor; in other words, the apparatus is not used as part of a system (e.g., an elevator, a hoist, etc.) that uses one or more motors to raise or lower a load.

[0027] In many embodiments, such a fall-protection apparatus may be a self-retracting lifeline (SRL); i.e., a deceleration apparatus comprising a housing that at least partially contains a drum-wound safety line that can be extended from the housing and retracted into the housing during normal movement of a human user of the apparatus, and which, upon the onset of a user fall, automatically arrests (i.e., slows to a controlled rate, e.g., completely stops) the fall of the user. An exemplary fall-protection apparatus (a self-retracting lifeline) 1 is depicted in Fig. 1. Various components of another exemplary self-retracting lifeline 1 are shown in partially exploded view in Fig. 2. Any such apparatus may comprise a housing 111 that is provided e.g. from a first housing piece 112 and second housing piece 113 that are assembled and fastened together to form the housing. (Fig. 2 depicts an exemplary prototype apparatus whose housing 111 differs somewhat from the housing 111 of the exemplary apparatus of Fig. 1.) Housing pieces 112 and 113 may be fastened together e.g. by bolts or by any other suitable fasteners. Various ancillary components such as e.g. one or more nuts, bolts, screws, shafts, washers, bushings, gaskets, bearings, labels, auxiliary housing pieces or shields, and the like, are omitted from the Figures herein for ease of presentation of components of primary interest; ordinary artisans will readily appreciate that any such items may be present as needed for the assembly and functioning of apparatus 1.

[0028] With reference to the exemplary apparatus of Figs. 2 and 3, within an interior space at least partially defined by housing 111 is a drum 90 comprising a spool 92 and sidewalls 93 and 94. Sidewalls 93 and 94 are axially spaced apart and define a receiving space 95 into which is wound (e.g., spiral-wound) a length of safety line 115 (with the term line broadly encompassing any elongate, windable load-bearing member, including e.g. webbing, cable, rope, etc., made of any suitable metal, synthetic or natural polymeric material, etc., and having any cross-sectional shape). A proximal end of line 115 is connected, directly or indirectly, to drum 90 (such a connection encompasses configurations in which the proximal end of line 115 is connected to a shaft 97 on which dmm 90 is mounted). Drum 90 is rotatably mounted within housing 111, e.g. by being rotatably mounted on a shaft 97 that is fixed to housing 111 (as in the exemplary design shown in Fig. 2) or by being fixed on a shaft that is rotatable relative to the housing. A drum-biasing member 96 (not visible in Fig. 2 but indicated in generic representation in Fig. 1, and which may be e.g. a suitable motor spring such as a spiral-coiled torsion spring) may be provided, which serves to bias the drum toward rotating in a direction that will retract safety line 115 onto the drum unless the biasing force is overcome e.g. by movement of a human user. Various types and arrangements of drum-biasing motor springs are described e.g. inU.S. Patents 9925400, 10556138 and 10792523 and inU.S. Provisional Patent Application 63 / 527997, all of which, including any PCT patent application and / or any U.S. patent application resulting from U.S. Provisional Patent Application 63 / 527997, are incorporated by reference herein in their entirety. (The ‘997 application discloses additional arrangements, including pawl-support infrastructure and / or a pawl-support plate that is integrated with a drum sidewall, particular ways of securing the distal end of a safety line to a drum spool, and others; any of the arrangements disclosed in the ‘997 application may be used in combination with the concepts disclosed in the present application.) A distal end of safety line 115 may comprise a gated connector 116 (which terminology broadly encompasses e.g. gated hooks, carabiners, and similar items) that allows the distal end of the safety line to be attached e.g. to a harness of a human user, to a secure anchorage, etc.

[0029] Braking device

[0030] Apparatus 1 comprises a rotationally-activated braking device 10 as indicated in exemplary embodiment in Fig. 2. Such a braking device relies on one or more velocity-actuated pawls 20. In the depicted embodiment, the at least one pawl 20 is fixedly co-rotatable with drum 90. By co-rotatable is meant that such a pawl “rotates” along with drum 90; that is, the pawl(s) moves in an orbital (circumferential) path about a center of orbital motion that coincides with the axis of rotation Raof the drum. By fixedly co-rotatable is meant that the pawl(s) are fixed in position relative to the drum so that they will always “rotate” (or remain stationary) along with the drum. In the illustrated embodiment, such an arrangement is achieved by mounting pawls 20 on a pawl-support plate 70 that is fixedly mounted on the same shaft 97 on which drum 90 is fixedly mounted (i.e., so that pawl-support plate 70 is axially co-mounted with drum 90) and that is thus likewise fixedly co-rotatable with drum 90. In such an arrangement, pawlsupport plate 70 and the pawl(s) 20 mounted thereon will rotate in lockstep with drum 90. In the exemplary arrangement of Fig. 2, this is achieved by fixedly axially co-mounting pawl-support plate 70 and drum 90 to a rotatable shaft 97, by way of main body 71 of pawl-support plate 70 comprising a central aperture 72 through which rotatable shaft 97 extends, with pawl-support plate 70 and drum 90 both being keyed to shaft 97 so that they cannot rotate relative to shaft 97. In some embodiments, pawl-support plate 70 may be directly attached to (or, may be an integral axial extension of) sidewall 94 of drum 90; such attachment may be in addition to, or may be a substitute for, an arrangement in which the pawl-support plate and the drum are both keyed to a common shaft.

[0031] In some embodiments, an arrangement in which pawl-support plate 70 and drum 90 are fixedly co- rotatable can be achieved by axially co-mounting pawl-support plate 70 and drum 90 on a shaft that is non- rotatable (relative to the housing of the apparatus) so that pawl-support plate 70 and drum 90 are both rotatable with respect to the shaft but are nevertheless in a fixed position relative to each other (e.g. are attached to each other); that is, they cannot rotate relative to each other. Any such relationship, however achieved (e.g. regardless of whether a rotatable shaft or a non-rotatable shaft is used), will be termed as pawl-support plate 70 being in fixed rotational relation with drum 90, and vice-versa. In any such arrangement, drum 90 and / or pawl-support plate 70 may be rotatably mounted on a non-rotatable shaft by way of any suitable bearing (whether a plain bearing, e.g. a bushing, a roller bearing, etc.), made of any suitable material(s).

[0032] In many embodiments, the one or more pawls 20 are configured (e.g. are pivotably mounted on a pawl-support plate 70) so that each pawl can pivotably move between a disengaged position and an engaged position. Such movement takes the form of pivoting about a pawl axis of pivoting (Pap, as indicated in Figs. 4 and 10b), and is different from the above-described “rotation” of pawl 20 along an orbital path around the overall axis of rotation Raof the pawl-support plate, drum, etc. Each pawl 20 comprises an engaging end 22 that is configured to engage with a tooth 121 of a ratchet 120 when the pawl is in an engaged position. Each pawl 20 is biased so that in ordinary use of the fall-protection apparatus, the engaging end 22 of pawl 20 is urged (e.g. radially inwardly) into a disengaged position in which it does not engage with any component (e.g. a ratchet tooth) that would limit the rotation of the pawl-support plate 70 and thus drum 90. (The two pawls 20 of Figs. 4 are both in a disengaged position; in this document, terminology such as a pawl moving into an engaged position will be understood to mean that the pawl pivotably moves so that an engaging end of the pawl moves into an engaged position.)

[0033] In the depicted embodiment, the biasing of a pawl 20 toward its disengaged position is performed by use of a biasing element (e.g. a magnet) 54 as indicated in Figs. 4 and 5 and as discussed in detail later herein. The biasing of the pawl(s) into the disengaged position allows pawl-support plate 70 and thus drum 90 to rotate freely thus allowing extension and retraction of safety line 115 in response to movements of a human user of the fall-protection apparatus as the user goes about their workplace activities. In the event that the drum begins to rotate in a particular manner as discussed in detail later herein, at least one pawl 20 will be motivated (overcoming the biasing force of biasing element 54) toward and into an engaged position in which the engaging end 22 of the pawl is able to physically contact a tooth of a ratchet to slow and / or stop the rotation of the drum. An exemplary ratchet 120 and teeth 121 thereof are depicted in exemplary embodiment in Fig. 2; however, many ratchet arrangements are possible, as discussed in detail later herein.

[0034] In use of such a rotationally -activated braking device, the engaging of at least one pawl with a tooth of a ratchet will at least slow, e.g. will stop, the rotation of the drum. Some such braking devices may bring the dmm to a “hard stop” in which the rotation of the drum ceases nearly instantaneously when the pawl engages the tooth. In arrangements in which a drum is brought to a “hard stop”, the safety line of such an apparatus may include a so-called shock absorber (e.g. a tear web or tear strip) to minimize the force experienced by a human user as the user is brought to a halt. (It will be understood that the term “hard stop” is used for convenience in describing a situation in which a drum is brought to a near-instantaneous stop; the term “hard stop” does not imply that the user is subjected to, e.g., excessively large forces in being brought to a halt.) Some braking devices may comprise a friction brake that, rather than bringing the drum nearly -instantly to a “hard stop”, brings the drum to a halt in a more gradual manner as discussed in detail later herein. This can minimize the force experienced by a human user as a fall is being arrested, e.g. without necessarily requiring the presence of a shock absorber in the safety line.

[0035] In one exemplary use of such a fall-protection apparatus 1, an upper, anchorage end 108 of the apparatus may be connected (e.g. by way of connection feature 114) to a secure anchorage of a workplace structure (e.g., a girder, beam or the like). The distal end of line 115 may then be attached (e.g., by way of gated connector 116) to a harness worn by a worker. (This description is for one exemplary type of selfretracting lifeline; ordinary artisans will know that other types of self-retracting lifelines, e.g. so-called “personal” self-retracting lifelines, are also in common use.) As the human user moves away from the anchorage, drum 90 rotates in an unwinding direction so that line 115 is extended from within housing 111. As the user moves toward the anchorage, drum 90 rotates in an opposing, winding direction (e.g. as urged by motor spring 96) so that line 115 is automatically retracted into housing 111 and wound upon drum 90. During such user activities, pawl(s) 20 are biased (e.g. by biasing elements 54) so that the engaging end 22 of a pawl 20 does not engage a tooth 121 of a ratchet 120 of the rotationally -activated braking device. In the event that the human user falls and causes line 115 to begin rapidly extending from housing 111, pawl 20 is actuated, meaning that an engaging end 22 of a pawl 20 is caused to move to an engaged position in which it engages with a ratchet tooth, whereupon the rotation of drum 90 is slowed, e.g. halted, and the falling of the worker is thereby arrested.

[0036] Velocity -actuated pawls

[0037] Fall-protection apparatus 1 comprises at least one pawl 20 that is a velocity -actuated pawl, mounted on a pawl-support plate 70. As shown in exemplary embodiment in various Figures herein, in some embodiments the at least one velocity-actuated pawl 20 may take the form of a pair of pawls 20. In some embodiments the pawls 20 of such a pair may be located in circumferentially -opposing positions from each other (i.e. , on opposite sides of the axis of rotation Raof drum 90 and pawl-support plate 70, when viewed along axis of rotation Ra) as evident e.g. in Figs. 3-6. In some embodiments, a pawl 20 may be pivotably mounted on a pawl-support plate 70 by way of an aperture 28 of pawl 20 being seated onto a pawl-support post 74 of pawl-support plate 70. Pawl-support post 74 and aperture 28 thus define the above-mentioned pivot axis Papof pawl 20. In some embodiments, aperture 28 of pawl 20 may be provided with a bushing (i.e., in the form of a hollow sleeve) 29 as shown in Fig. 4. The inner surface of pawl-bushing 29 will be in contact with the outer surface of pawl-support post 74. Pawl-bushing 29 may be comprised of a suitable material, e.g. an organic polymeric material such as polyoxymethylene, polyamide, and so on, that will provide a suitably smooth inner and / or outer surface to allow smooth pivoting of pawl 20 relative to post 74. In various embodiments, such a bushing 29 may be made of a material that exhibits a Shore Hardness (D scale) of from at least 20, 40, or 60 to at most 90, 80 or 70. A variety of bushings that may be suitable (e.g., bushings whose bearing surface exhibits a low coefficient of friction) are available from Igus Gmbh, Cologne, Germany, under the trade designation IGLIDE. In some embodiments, the above-described arrangements may be reversed, i.e. the pawl may comprise a post with the pawl-support plate comprising an aperture to receive the pawl-post. In some embodiments no bushing may be present; rather, metal-to- metal contact between an aperture and a post may exist.

[0038] As evident from the view of Fig. 6, the at least one pawl 20 is configured so that upon rotation of pawl-support plate 70 around the axis of rotation Ra, pawl(s) 20 will follow a generally circumferential orbital path around axis of rotation Ra. When drum 90 and pawl-support plate 70 are rotating at a velocity below a particular threshold value, pawl(s) 20 will remain in a disengaged position. All such pawls 20 will typically remain in their fully disengaged position (meaning that they are moved as far in their disengaging direction as possible, by the force of their biasing element(s) 54) when drum 90 and pawl-support plate 70 are stationary or rotating slowly as a user of the fall-protection apparatus goes about work activities. Each of the pawls 20 of Fig. 6 is shown in such a (fully) disengaged position, held in this position by a biasing element (magnet) 54.

[0039] In Fig. 6, the biasing force that biasing element 54 exerts on pawl 20 is generally indicated by the arrow marked Pbf, and is achieved by way of biasing magnet 54 exerting an attractive force on leading section 24 of pawl 20. For convenience of description, leading section 24 of pawl 20 can be considered to have an effective center of mass (barycenter) 35, with the attractive force that is imposed by biasing magnet 54 on leading section 24 of pawl 20 being considered as being exerted generally on the center of mass 35 of leading section 24 of pawl 20. This center of mass 35 of leading section 24 of pawl 20 will necessarily be positioned forward (i. e. , in a leading direction, toward leading / engaging end 22 of pawl 20) of the overall center of mass 34 of the entire pawl 20 (discussed in further detail later herein), as indicated in generic representation in Fig. 6. (Center of mass 35 of leading section 24 of pawl 20, and overall center of mass 34 of the entire pawl 20, are evaluated when viewing the pawl 20 along the previously -discussed “a” axis, i.e. with the pawl viewed as in Figs. 6-8.)

[0040] In some embodiments, biasing magnet 54 and pawl 20 will be configured so that when pawl 20 is in its (fully) disengaged position (and when the inertia disk 40 on which biasing magnet 54 is mounted is in its home position as discussed in detail later herein), biasing magnet 54 will be positioned generally radially inwardly from, and closely abutting, the center of mass 35 of leading section 24 of pawl 20. In some embodiments, biasing magnet 54 will be radially -oriented so that its zone of maximum magnetic force extends generally radially (e.g., the magnet will be oriented so that its north and south poles are generally radially aligned with each other), as in the exemplary arrangement depicted in Fig. 6.

[0041] A velocity-actuated pawl 20 is a pawl that is actuated (i.e., caused to pivotably move from a disengaged position, toward, and into, an engaged position) when the velocity of the pawl 20 along its orbital path exceeds a predetermined threshold value. For convenience, the velocity of the pawl will be referred to herein as rotational velocity. This will be understood to refer to the velocity of a pawl along its orbital path as dictated by the rotation of the pawl-support plate; this should not be confused with pivotable movement of the pawl about pawl pivot axis Pap. In some embodiments, a velocity -actuated pawl 20 may not be not significantly actuated by any acceleration that the pawl may be experiencing; however, the acceleration of some other item (e.g. an inertia disk) may modulate the velocity-response of the pawl, as discussed in detail later herein.

[0042] As noted above, in some embodiments a velocity-actuated pawl 20 can be biased toward a disengaged position by way of a biasing element 54 in the form of a magnet (e.g., a permanent magnet) that is mounted on some component of the braking device 10. A magnet that performs this function will be referred to herein as a biasing magnet and will be distinguished from a magnet that serves as a damping magnet, as discussed in detail later herein. In the depicted embodiment, biasing magnets 54 are mounted in an inertia disk 40 of braking device 10, for reasons discussed in detail later herein. Pawl(s) 20 may be made of any suitable ferromagnetic material; for example, a metal or metal alloy such as stainless steel (in particular, martensitic stainless steel) or galvanized steel, nickel, etc., that renders the pawl susceptible to a magnetic force. In various embodiments, any such material of which pawl 20 is made may exhibit a Relative Magnetic Permeability of greater than 100, 500, 1000, 5000, or 10000.

[0043] With biasing magnet 54 in an appropriate position, the attractive magnetic force of biasing magnet 54 on the leading section 24 of pawl 20 will cause pawl 20 to move toward, e.g. to remain in, a disengaged position as shown e.g. in Figs. 4 and 6. Exceeding a particular rotational velocity threshold will cause pawl 20 to overcome the biasing force of biasing magnet 54 so that pawl 20 pivotably moves toward, e.g. into, an engaged position. (Strictly speaking, pawl 20 will not “engage” with a ratchet tooth 121 until its engaging end 22 actually contacts the tooth. However, for purposes of description, a pawl will be considered to be in an engaged position upon the pawl having been actuated so that its engaging end is in a position (e.g. having moved radially outward) in which it will contact a ratchet tooth upon continued motion of the pawl along its orbital path.)

[0044] Pawl 20 comprises a pivot axis Papthat is aligned with (and defined by) a pivotable connection of pawl 20 with pawl-support plate 70 as discussed above. In the depicted design, the pivot axis of pawl 20 is generally in the midsection of pawl 20. Thus as indicated e.g. in Figs. 10a and 10b, pawl 20 comprises a leading section 24 that is positioned forward (that is, in a leading direction) of the pivot axis, and a trailing section 37 that is positioned rearward (that is, in a trailing direction) of the pivot axis. Exemplary pawl 20 as depicted herein has a “rocker” configuration in which, when the pawl moves from its disengaged position to its engaged position, the leading section 24 of pawl 20 (which includes the engaging end 22 of the pawl) move radially outward and the trailing section 37 of the pawl moves radially inward. By definition, a “rocker” pawl will comprise a trailing / leading ratio of at least 33 %. By this is meant the ratio of the linear distance from the pawl’s pivot axis to the trailing terminus of the pawl, to the linear distance from the pawl’s pivot axis Papto the leading terminus of the pawl. In various embodiments, a rocker pawl may exhibit a trailing / leading ratio of at least 40, 50, 60, or 70 %. By way of a specific example, pawls 20 as depicted e.g. in Fig. 6 exhibit a trailing / leading ratio of approximately 73 %. A “rocker” pawl can be contrasted to a pawl that has a relatively short trailing section, e.g. the pawls depicted in Fig. 10 of U.S. Patent 11779783 (which exhibit a trailing / leading ratio of approximately 25 %). In some embodiments, the trailing end of a rocker pawl can be configured to have one or more surfaces that (e.g. in combination with an item such as a buttress 80 of pawl-support plate 70 as discussed later herein) participate in defining the engaged position of the pawl and / or that participate in transferring a load that develops upon fall-arrest so that the entire load is not borne by the to the pawl-support post 74.

[0045] In Figs. 6 and 7, pawls 20 are shown in their disengaged position; in Fig. 7, the radially-outward direction in which the leading section 24 of pawl 20 will move toward an engaged position is indicated by the arrow “E”, with the radially -inward direction in which trailing section 37 will move being indicated by arrow 36. Fig. 8 shows both pawls 20 having moved out of their disengaged position; the lower pawl is shown as having moved completely into an engaged position; the upper pawl is shown as not having fully completed the movement into an engaged position. As noted, the pivot axis Papof pawl 20, and pawl 20 as a whole, will follow an orbital path as drum 90 and pawl-support plate 70 rotate about axis of rotation Ra. Pawl 20 comprises an overall center of mass (indicated generally by reference number 34 in various Figures) that likewise follows an orbital path as the dmm and the pawl-support plate rotate about the axis of rotation. In a velocity -actuated pawl 20, center of mass 34 and pivot axis Ramay be at least substantially radially aligned with each other (in other words, center of mass 34 and pivot axis Ramay be at least substantially the same radial distance from axis of rotation Raand thus will substantially follow the same orbital path around axis of rotation Ra). However, as evident e.g. in Fig. 8, the center of mass 34 of pawl 20 is circumferentially offset from the pivot axis Papof pawl 20, along the orbital path of the center of mass and the pivot axis. As pawl-support plate 70 rotates about axis Ra, a radially-outward centrifugal force will develop on center of mass 34. The circumferential offset between the pivot axis Papof pawl 20 and the overall center of mass 34 of pawl 20 will cause pawl 20 to be urged to pivotably move about pivot axis Papso that center of mass 34, and thus leading section 24 of pawl 20, move generally radially outward. In general, the circumferential offset (and / or any radial offset) between center of mass 34 and pivot axis Papof a pawl 20 can be any suitable value. Further details of velocity-actuated pawls, various ranges in which e.g. a circumferential offset may be set, and so on, are discussed in detail in U.S. Patents 11779783 and 11759662, both of which are incorporated by reference in their entirety herein.

[0046] According to the principles outlined above, a rotational velocity of pawl-support plate 70 above a particular threshold will cause engaging end 22 of pawl 20 to be urged generally radially outward toward, and eventually into, an engaged position. The above explanations were phrased in terms of “centrifugal force” acting to urge the center of mass 34 of pawl 20 generally radially outward. Strictly speaking, centrifugal force is a fictitious or “pseudo” force. What actually occurs is that the inertia of center of mass 34 tends to cause center of mass 34 to deviate radially outward (i.e. to attempt to continue in a straight path) rather than following an arcuate orbital path. However, the concept of centrifugal force is well-established and is perfectly suited for discussing the motion of a pawl 20 using a frame of reference that rotates with pawl-support plate 70 and pawl 20. So, for convenience of description, the term centrifugal force is used in the discussions herein.

[0047] As noted, in embodiments in which the center of mass 34 and the pivot axis Papof a pawl 20 are at least generally radially aligned with each other, the center of mass 34 will at least substantially follow the same orbital path as pivot axis Pap. This has the effect that any rotational acceleration (i.e. a change in the absolute rotational velocity) of pawl 20 may have relatively little tendency to urge the center of mass, or the engaging end 22, of pawl 20, either generally radially outward or inward. Thus in some embodiments, pawl 20 will be responsive to the absolute rotational velocity of pawl 20 along its orbital path, but will be relatively less responsive to acceleration along this orbital path. However, it may not necessarily be required that a velocity-actuated pawl must be completely insensitive to rotational acceleration; thus, in various embodiments, a velocity-actuated pawl may be generally, substantially, or essentially unresponsive to rotational acceleration. To reduce (e.g. substantially eliminate) any responsiveness of the pawl to rotational acceleration, it may not necessarily be required that pivot axis Papand center of mass 34 are “exactly” radially aligned with each other. That is, in any real-life apparatus, small adjustments may be made in view of the fact that, for example, frictional effects may occur, gravitational effects may occur, inertial effects may occur, and so on. So in some instances, it may be acceptable, or even desirable, that there be a deliberate (although typically small) radial-alignment-mismatch between pivot axis Papand center of mass 34. Thus the condition is applied as stated above, that pivot axis Pap and center of mass 34 may be “at least substantially ” radially aligned with each other, meaning that they are aligned within plus or minus 10 %. In some embodiments, pivot point Papand center of mass 34 may be at least essentially radially aligned with each other, meaning within plus or minus 5 %. In some embodiments, they may be radially aligned with each other within plus or minus 2 %. (Any such measurement will be performed with pawl 20 in a fully disengaged position.)

[0048] Acceleration-modulation of velocity -actuation of pawls

[0049] The discussions above reveal that a velocity-actuated pawl 20 as disclosed herein is typically configured so that it is not significantly actuated by any rotational acceleration that the pawl (or a pawlsupport plate 70 to which it is attached) experiences. However, according to the arrangements herein, the velocity -actuation of the pawl can be modulated by an acceleration that is experienced by another item, for example an inertia disk 40 as depicted in exemplary embodiment in various Figures herein. Such an inertia disk 40 can be mounted on shaft 97 of apparatus 1 (i.e., axially co-mounted with pawl-support plate 70 and with drum 90) e.g. so that pawl-support plate 70 and pawl(s) 20 are axially sandwiched between inertia disk 40 and drum 90, as evident e.g. from Fig. 2. In some embodiments, a spacer disk (not shown in any Figure) may be positioned axially between inertia disk 40 and pawl-support plate 70, to establish and maintain a desired axial spacing (e.g. of from 0.2 mm to 1.0 mm) between major axial face 44 of inertia disk and major axial face 73 of pawl-support plate 70. Such a spacer disk may be made of any suitable material (e.g. an organic polymeric material) and may have any suitable radial size. (In particular, such a spacer disk may be much smaller in radial size than inertia disk 40 and pawl-support plate 70, as long as the spacer disk is able to maintain the desired spacing.)

[0050] In the depicted embodiment, inertia disk 40 is co-rotatable with pawl-support plate 70 and thus with dmm 90. However, inertia disk 40 is not fixed relative to pawl-support plate 70 (nor to drum 90); rather, it is able to rotate relative to plate 70 (about axis Ra) through a limited, predetermined range of rotational motion. (Inertia disk 40 may be mounted e.g. on any suitable bearing, e.g. a roller bearing, a plain bearing (e.g. a bushing), etc., made of any suitable material, to facilitate this.) Inertia disk 40 is biased to a home (rotational) position relative to pawl-support plate 70 (and thus to drum 90). The biasing of inertia disk 40 is such that in ordinary use of apparatus 1, inertia disk 40 will remain stationary with respect to pawl-support plate 70 the majority of the time; it is only in certain instances (e.g. in the event of a user fall) that inertia disk 40 may rotate relative to pawl-support plate 70. Inertia disk 40 will thus remain in its home position unless it is subjected to a force that overcomes the biasing force on inertia disk 40 and causes inertia disk 40 to rotate, relative to pawl-support plate 70, in a trailing direction toward, e.g. into, an activated position.

[0051] In the depicted embodiment, the previously -described biasing element (magnet) 54 that biases pawl 20 toward its home position, is mounted on inertia disk 40. When inertia disk 40 is in its home position, rotation of dmm 90 and pawl-support plate 70 above a predetermined first threshold value of rotational velocity can overcome the pawl-biasing force applied by biasing magnet 54 and cause the engaging end of the pawl to be urged by centrifugal force into an engaged position in which it can engage a tooth of the ratchet. When inertia disk 40 is rotated away from its home position, toward (e.g., into) its activated position, magnet 54 will be moved generally circumferentially away from center of mass 35 of leading section 24 of pawl 20 thus reducing the biasing force that magnet 54 applies to leading section 24 of pawl 20. When inertia disk 40 is in its activated position, rotation of drum 90 and pawl-support plate 70 above a predetermined second threshold value of rotational velocity can overcome the pawl-biasing force and cause the engaging end of the pawl to be urged by centrifugal force into an engaged position in which it engages a tooth of the ratchet. As disclosed herein, the predetermined second threshold value of rotational velocity is lower than the predetermined first threshold value of rotational velocity. Inertia disk 40 is biased toward the home position and is rotatable relative to the pawl-support plate from the home position to the activated position, upon the inertia disk experiencing a rotational acceleration that is above a predetermined threshold value. Thus, when the inertia disk is experiencing a low level of acceleration, it will remain in the home position and the pawl can only be actuated by exposing the pawl to the first, higher threshold of rotational velocity. If the inertia disk is experiencing a sufficiently high level of acceleration (sufficient to overcome the biasing of the inertia disk toward the home position), the inertia disk will rotate, relative to the pawlsupport plate, into the activated position. With the inertia disk in the activated position, the pawl can be actuated by exposing the pawl to the second, lower threshold of velocity. In other words, the pawl can be actuated at a lower velocity, if the pawl-support plate is experiencing high acceleration.

[0052] These arrangements, and their functioning, are illustrated in exemplary manner in Figs. 6-8. In Fig. 6, inertia disk 40 is in a home position and each pawl 20 is in a disengaged position. Biasing magnet 54 of inertia disk 40 closely abuts the previously-described center of mass 35 of leading section 24 of pawl 20. The close abutment of biasing magnet 54 to center of mass 35 of leading section 24 of pawl 20 means that a relatively high rotational velocity of pawl-support plate 70 would be needed in order for the centrifugal force on pawl 20 to overcome the biasing imposed by magnet 54 so as to cause pawl 20 to pivotably move to an engaged position. So as long as the acceleration to which inertia disk 40 is exposed, and the velocity to which pawls 20 are exposed, remains relatively low (e.g., in ordinary use of the apparatus), inertia disk 40 will remain in the home position relative to pawl-support plate 70 (and will rotate in unison with plate 70) and pawls 20 will remain in their disengaged position.

[0053] An event such as e.g. a user fall will cause drum 90, pawl-support plate 70, and inertia disk 40 to be subjected to rotational acceleration. If sufficient rotational acceleration is present, this will overcome the biasing of inertia disk toward its home position and will cause inertia disk 40 to rotate relative to pawl- support plate 70 in direction “A” (specifically, in the trailing / winding direction T / W) as indicated in Fig. 6. (In actuality, the entire assembly of drum 90, pawl-support plate 70, and inertia disk 40, will be rotating in the unwind direction; the rotation of inertia disk 40 in this direction will “lag” behind the rotation of plate 70 and drum 90. This movement of inertia disk 40 relative to plate 70 and drum 90 will thus be occasionally referred to herein as “lag-rotation”.)

[0054] In some instances, inertia disk 40 may move through the entire permitted range of rotation so as to arrive in its activated position as shown in Fig. 7. Fig. 7 reveals that biasing magnet 54, being fixed in position on inertia disk 40, has now moved generally circumferentially in a trailing direction so as to be further away from center of mass 35 of leading section 24 of pawl 20. This causes a decreased magnetic force to be experienced by center of mass 35 and by leading section 24 in general, with the result that the leading section 24 of pawl 20 can now move radially outward (as indicated by arrow “E”) in response to a rotational velocity that is relatively low. In other words, with inertia disk 40 having moved to an activated position, pawl 20 can be actuated by a lower rotational velocity than is required when inertia disk 40 is in the home position. One or more of pawls 20 may thus be actuated so that the braking device assumes a configuration shown in Fig. 8. In Fig. 8, the inertia disk 40 is still in the activated position. The lower pawl 20 is shown as having moved into an engaged position, while the upper pawl 20 is shown as not yet having fully completed the movement into the engaged position. (In any actual, real-life apparatus, one pawl may be actuated before another pawl; or, multiple pawls may be more or less simultaneously actuated).

[0055] Displacement ratio

[0056] In various embodiments, the closely -abutting distance between biasing magnet 54 and the center of mass 35 of the leading section 24 of pawl 20 may be less than 11, 9.0, 7.0, 5.0, or 3.0 mm, when inertia disk 40 is in its home position and when pawl 20 is in its disengaged position. In various embodiments, the distance between biasing magnet 54 and the center of mass 35 of the leading section 24 of pawl 20 may be greater than 8.0, 10, 12, 14, 16 or 18 mm when inertia disk 40 is in its activated position and with pawl 20 still in its disengaged position. (All such distances will be measured at the location of closest approach of the two entities.)

[0057] It will be appreciated that the absolute value of such parameters may vary with the particular design, e.g. size, of the braking device. However, these parameters allow the formulation of a displacement ratio that more generally characterizes the extent of movement of biasing magnet 54 relative to center of mass 35 as inertia disk 40 moves from a home position to an activated position. As defined herein, the numerator of this ratio is the distance between biasing magnet 54 and center of mass 35 when inertia disk 40 is in its activated position and pawl 20 is in its engaged position (e.g., as with inertia disk 40 and lower pawl 20 as shown in Fig. 8). The denominator of this ratio is the distance between biasing magnet 54 and center of mass 35 when inertia disk 40 has moved to its activated position and with pawl 20 remaining in its disengaged position (e.g., as with inertia disk 40 and pawls 20 as shown in Fig. 7). In various embodiments, such a displacement ratio may range from at least 1.2, 1.3, 1.4, 1.5, 1.6, 1.8, or 2.0, to at most 5.0, 4.0, 3.0, 2.1, 1.9, 1.8, 1.7, 1.6, or 1.5. (The exemplary arrangement depicted in Figs. 6-7 exhibits a displacement ratio of approximately 1.6.)

[0058] The movement of biasing magnet 54 relative to center of mass 35 as inertia disk 40 moves from a home position to an activated position may also be characterized in terms of the angular displacement of biasing magnet 54 along its orbital (circumferential) path. In some embodiments, this orbital movement of biasing magnet 54 will at least generally correspond to an arc of partial rotation that inertia disk 40 travels through as it moves from its home position to an activated position as discussed later herein. Thus in various embodiments, biasing magnet 54 may move relative to center of mass 35 through an arc of at least 4, 5, 6, 8 or 10 degrees, to at most 30, 25, 20, or 15 degrees, as inertia disk moves from a home position to an activated position.

[0059] The above discussions have been phrased in terms of the velocity-actuation of a pawl 20 being modulated by a sufficient rotational “acceleration” that an inertia disk 40 is subjected to. In this regard it is noted that, strictly speaking, any entity (e.g. an inertia disk 40) that is following an orbital path is continuously experiencing acceleration, due to the change in the direction of motion. (In other words, velocity is a vector quantity, and any change in the magnitude or direction of the velocity, corresponds to acceleration.) Those of ordinary skill will appreciate that the terms “acceleration” and “rotational acceleration” as used herein specifically denote so-called tangential acceleration of a entity that is following an orbital path. In other words, the acceleration that is used herein to modulate the velocity -response of a pawl, corresponds to a change in the magnitude of the velocity of a body along its orbital path; acceleration that results merely from the body following an orbital path at constant velocity (i.e. , centripetal acceleration) has little or no effect.

[0060] The advantages of the above-described arrangements will be evident to ordinary artisans. The rotational velocity at which a velocity-actuated pawl will be actuated can be modulated in view of acceleration that is experienced by an inertia disk. So, a low-acceleration event will not be likely to cause the pawl(s) to engage unless and until a high rotational velocity is present, while in a high-acceleration event, the pawls will engage in response to a much lower rotational velocity. This can reduce the number of inadvertent engagements of the pawl (nuisance lock-ups of the braking device) e.g. as a worker moves, walks, crouches, and so on, while also having the result that the pawls will engage more quickly in the event of an actual fall, thus reducing the distance that a human user falls and commensurately reducing the fallarrest force experienced by the user.

[0061] Co-biasing

[0062] The above-discussed arrangements rely on inertia disk 40 being biased toward its home position. In the above-discussed exemplary arrangements, this is achieved by way of one or more biasing magnets 54 that are mounted on inertia disk 40. In some embodiments, inertia disk 40 may be biased toward its home position, by the same biasing magnet 54 that biases a pawl 20 toward its disengaged position (such an arrangement will be termed as pawl 20 and inertia disk 40 being co-biased). Thus in the exemplary arrangement depicted e.g. in Figs. 4 and 6, inertia disk 40 is equipped with two biasing magnets 54. One of the biasing magnets 54 biases the upper pawl 20 toward its disengaged position; the other biasing magnet 54 biases the lower pawl 20 toward its disengaged position. This is accomplished by way of each magnet exerting an attractive force on the leading section 24 of its neighboring pawl 20, which serves to urge the leading section of the pawl radially inward. And, both of the biasing magnets 54 collectively bias inertia disk 40 toward its home position. This is accomplished by way of the attractive force between each biasing magnet 54 and the leading section 24 of its neighboring pawl, which serves to urge the biasing magnet (and thus the inertia disk on which the magnet is mounted) to rotate in the leading direction, toward the home position of the inertia disk. Thus, in the disclosed arrangement, a biasing magnet can perform “double duty” . That is, the same biasing magnet can bias a pawl toward its disengaged position and can bias an inertia disk toward its home position. Such an arrangement will be distinguished from arrangements in which an inertia disk is biased by a magnet that biases only the inertia disk and a pawl is biased by a different magnet that biases only the pawl.

[0063] It will be appreciated that a co-biased arrangement of the general type described above may provide enhanced responsiveness, due to the fact that a single magnet is biasing two different items, both of which are able to move. That is, with reference to Figs. 6-8, when inertia disk 40 rotates in a trailing direction away from its home position, biasing magnet 54 will necessarily move in that same trailing direction, generally circumferentially away from the center of mass 35 of the leading section 24 of pawl 20. This will not only increase the distance from the biasing magnet 54 to the center of mass 35 of leading section 24 of pawl 20, it will also move the biasing magnet 54 so that the center of mass 35 of leading section 24 of pawl 20 is circumferentially offset from the magnet’s zone of maximum attractive force (which will extend generally radially outward from the radially -outward face of the magnet). Also, the force that magnet 54 exerts on center of mass 35 will now be at a rather high angle relative to the direction of rotation of center of mass 35 about the pawl pivot axis Pap, as evident from Fig. 7. (In comparison, when biasing magnet 54 is in its home position, the force that magnet 54 exerts on center of mass 35 will be generally aligned with the direction of rotation of center of mass 35 about the pawl pivot axis Pap, as evident from Fig. 6.) So, with biasing magnet 54 having moved away from its home position, the magnetic force vector that magnet 54 exerts on center of mass 35 will be along a direction that has a reduced moment arm with respect to rotation about the pawl pivot axis Pap.

[0064] All of these factors will cause that as biasing magnet 54 moves (with inertia disk 40) away from the home position, the magnetic force vector that biasing magnet 54 applies to center of mass 35 of leading section 24 of pawl 20 will drop in magnitude and will experience a reduction in its moment arm. The result is that as biasing magnet 54 moves away from the home position, the biasing force (torque) that magnet 54 exerts on the leading section 24 of pawl 20 will drop at an even steeper rate than the already highly nonlinear (e.g. approximately inverse square) relationship that would exist if the magnet and the center of mass 35 of leading section 24 were to simply, e.g., be moved farther apart along the zone of maximum attractive force of the magnet. In the depicted embodiment, the inertia disk 40 can rotate to an activated position in which, as evident in Fig. 7, biasing magnet 54 is located generally radially inward from the pivot axis Papof pawl 20. At this point the biasing torque that magnet 54 applies on leading section 24 of pawl (Pbf as indicated in Fig. 6) will have dropped to a very low value, so that a small rotational velocity is all that is needed in order to move the pawl out of its disengaged position.

[0065] Furthermore, as pawl 20 moves out of its disengaged position toward its engaged position, the distance from magnet 54 to center of mass 35 of leading section 24 of pawl 20 will increase still further. This will further decrease the biasing force on inertia disk 40 (e.g. in an inverse square manner), which will allow inertia disk 40 to move still further (if it has not already reached its activated position), which will in turn allow pawl 20 to move still further, and so on. In other words, the herein-disclosed arrangements enable an autoaccelerating mode of inertia disk activation / pawl actuation in which movement of inertia disk 40 out of its home position decreases the biasing force on pawl 20 and movement of pawl 20 out of its disengaged position in turn decreases the biasing force on inertia disk 40, and so on. Such arrangements can be contrasted e.g. with spring-biased arrangements in which the biasing force on an item increases as the item moves away from a home or disengaged position, due to the biasing spring exerting a higher force (in accordance with Hooke’s law) as the spring is deformed away from a resting condition. It will be appreciated that an autoaccelerating mode of activation / engagement, as facilitated by a co-biasing arrangement of the general type described above, can significantly enhance the responsiveness of the braking device.

[0066] The amount of rotation of inertia disk 40 relative to pawl-support plate 70 in moving from a home position (as in Fig. 6) to an activated position (as in Fig. 7) may be any suitable range. In various embodiments, this arc of partial rotation may be at least 4, 5, 6, 8 or 10 degrees. In further embodiments, this arc of partial rotation may be at most 30, 25, 20, or 15 degrees. (By way of a specific example, in the exemplary arrangement illustrated in Figs. 6 and 7, the range of rotation (arc of partial rotation) of inertia disk 40 is approximately 15 degrees.) It is noted that in some situations, inertia disk 40 may not necessarily be subjected to sufficient acceleration to travel over this entire range; that is, under some circumstances inertia disk 40 may cease moving and may return to the home position without reaching the limit of the permitted rotational range.

[0067] The limiting of the rotation of inertia disk 40 relative to pawl-support plate 70 to a predetermined range, in particular the establishing of the home position of the inertia disk and the activated position of the inertia disk, may be achieved in any suitable manner. In some embodiments, this may be accomplished by way of a buttress 80 that is mounted on pawl-support plate 70 and that extends axially from pawl-support plate 70. In some embodiments, such a buttress 80 may be integral with pawl-support plate 70, e.g. buttress 80 may be an axially -extending integral portion of pawl-support plate 70.

[0068] In the exemplary arrangement shown e.g. in Figs. 3-5, buttress 80 is used to limit the rotation of inertia disk 40. In the illustrated embodiment, inertia disk 40 and pawls 20 and buttress 80 are generally coplanar. By this is meant that at least a substantial portion of buttress 80, and the main body of pawls 20 (excluding a ballast element 26 as discussed later herein), lie generally in the same plane as inertia disk 40, as most easily seen in Fig. 4. Such an arrangement can be contrasted with arrangements in which an inertia disk is axially offset from one or more pawls. In the illustrated embodiment, inertia disk 40 is provided with at least one radially-outward-open-ended notch 45 in which no material of inertia disk 40 is present, in order to accommodate pawls 20 and buttress 80 in the same plane as inertia disk 40. (In the illustrated embodiment, inertia disk 40 has two such notches 45, each of which accommodates one of the two buttresses 80 and one of the two pawls.)

[0069] In the depicted embodiment, each notch 45 of inertia disk 40 is defined by a leading end 46 and a trailing end 48. Each notch subtends an arc of approximately 115 degrees (the term “notch” is thus used broadly and does not require that the “notch” be particularly narrow or sharp). In the depicted embodiment, inertia disk 40 comprises a first contact surface 49 that is located within notch 45 and that faces generally in a leading direction. Buttress 80 of pawl-support plate 70 comprises a first inertia-disk-contacting surface 83 that faces generally in a trailing direction. When inertia disk 40 is in its home position, first contact surface 49 of inertia disk 40 will be in contact with first inertia-disk-contacting surface 83 of buttress 80, as evident in Figs. 4 and 6. In the depicted embodiment, inertia disk 40 comprises a radially -outwardly - protruding shoulder 51 that is located within notch 45. Shoulder 51 of inertia disk 40 comprises a second contact surface 52 that faces generally in a trailing direction. Buttress 80 of pawl-support plate 70 comprises a second inertia-disk-contacting surface 84 that faces generally in a leading direction. When inertia disk 40 is in its activated position, second contact surface 52 of inertia disk 40 will be in contact with second inertiadisk-contacting surface 84 of buttress 80, as evident in Fig. 7. Such a combination of contact surfaces in inertia disk 40, and inertia-disk-contacting surfaces in buttress 80 of pawl-support plate 70, can thus limit the rotational travel of inertia disk 40 and in particular can establish the home position and activated position of inertia disk 40.

[0070] In some embodiments, the same buttress 80 that comprises contacting surfaces that limit the rotational travel of inertia disk 40, can perform a similar function for pawl 20. In the illustrated embodiment, buttress 80 comprises a second pawl-contacting surface 81 (indicated e.g. in Fig. 5) that faces generally radially outward, and pawl 20 comprises a second contact surface 32 that is located on trailing section 37 of pawl 20 and that faces generally radially inward. When pawl 20 is pivotably moved into its engaged position, the second contact surface 32 of pawl 20 comes into contact with the second pawl-contacting surface 81 of buttress (as shown in Fig. 8) thus establishing the engaged position of pawl 20 and limiting any further movement of pawl 20 in the engaging direction.

[0071] In the depicted embodiment, buttress 80 does not participate in establishing the disengaged position of pawl 20. Rather, a first pawl-contacting surface 76 is provided in a cavity 75 of pawl-support plate 70, as most easily seen in Fig. 3. Cavity 75 (described in more detail later herein) is axially recessed relative to major surface 73 of pawl-support plate 70, and is axially -open-ended as evident from Fig. 3. (The exemplary cavity 75 as depicted in Fig. 3 is also radially-outwardly-open-ended, but it does not necessarily have to be.) Pawl 20 comprises a first contact surface 31 that is on a leading section 24 of pawl 20, as most easily seen in Fig. 5. When pawl 20 is in its disengaged position, the first contact surface 31 of pawl 20 is in contact with the first pawl-contacting surface 76 of pawl-support plate 70, as most easily seen in Fig. 7. Thus in the depicted embodiment, the disengaged position of pawl 20 is dictated by first pawl-contacting surface 76 of the pawl-support plate 70 rather than by any surface of buttress 80. However, in various embodiments, any suitable arrangement may be used. For example, an extension of buttress 80 (or an additional, separate buttress) that interacts with the trailing portion of pawl 20, may be used to establish the disengaged position of pawl 20.

[0072] In the depicted embodiment, buttress 80 comprises a third pawl-contacting surface 82, as seen most easily in Figs. 3 and 6. Third pawl-contacting surface 82 faces generally in a leading direction, and is configured so that when pawl 20 is in an engaged position, a third contact surface 33 of pawl 20, that faces generally in a trailing direction, is in contact with third pawl-contacting surface 82 of buttress 80, as seen e.g. in Fig. 8. Third pawl-contacting surface 82, and buttress 80 as a whole, is designed so that when pawl 20 is in the engaged position, a force-transmitting (load-bearing) path is formed between the trailing section 37 of pawl 20, and buttress 80. A load that develops on pawl 20 upon pawl 20 engaging with a ratchet can thus be transmitted into buttress 80 (and thence to pawl-support plate 70). In some embodiments, this can at least substantially reduce the load that would otherwise be transmitted through the pawl-support post 74 that the pawl resides on (although in some embodiments the pawl-support post 74 may still bear a portion of the load, e.g. less than 40, 30, or 20 % of the total load).

[0073] The above discussions make it clear that in various embodiments, a buttress 80 of pawl-support plate 70 can participate at least to an extent in limiting the rotational travel of an inertia disk and / or in limiting the pivotable motion of a pawl, and / or can participate at least to an extent in providing a loadbearing pathway that bears the load that develops when the pawl is engaged with a ratchet.

[0074] Configurations in which a pawl 20 and / or a buttress 80 of a pawl-support plate 70 are located within a notch 45 of an inertia disk in the general manner described above can advantageously provide a compact arrangement. Thus in some embodiments, a pawl and / or a buttress can reside within a notch of an inertia disk. By this is meant that all portions of the pawl and / or buttress that are generally coplanar with the inertia disk, reside within the notch. In this context, to reside within a notch means to lie radially inside of an imaginary circle that coincides with the radially -outward perimeter 56 of the inertia disk (a portion of such an imaginary circle is shown in the form of dashed line 57 in Fig. 6). It is noted in passing that when inertia disk 40 is in its home position and pawl 20 is in its disengaged position, surface 47 of inertia disk 40 (as seen e.g. in Figs. 4 and 5) that is located generally toward the leading end 46 of notch 45 of inertia disk 40, is not in contact with any portion of pawl 20, as evident from inspection of Fig. 7. In particular, surface 47 of inertia disk is not in contact with first contact surface 31 of pawl 20; rather, first contact surface 31 of pawl 20 is in contact with first pawl-contacting surface 76 of cavity 75 of pawl-support plate 70 as described earlier herein.

[0075] With regard to pawl-support post 74, in various embodiments such a pawl-support post may be e.g. integral with pawl-support plate 70; or, it may be a separately-made item that is attached to pawl-support plate 70, e.g. on a pawl-support pedestal 77. The above-discussed collection of components of pawl-support plate 70 (e.g. buttress 80, pawl-support post 74, pawl-support pedestal 77 if present, and cavity 75 if present), may be collectively termed “pawl-support infrastructure”. In various embodiments, at least portions of such pawl-support infrastructure may be integral with pawl-support plate 70, which in turn may be integral with drum 90. In such embodiments, drum 90, pawl-support plate 70, and so on, may be made of any material that exhibits properties commensurate with the desired strength. In various embodiments, dmm 90 may be made of a molded polymer such as e.g. glass-fiber-reinforced nylon; or, drum 90 may be made of a metal such as e.g. cast or machined aluminum. In some embodiments, it may be advantageous to make pawl-support plate 70 and / or drum 90 out of an electrically conductive material (for reasons discussed later herein), e.g. a material that comprises a specific conductance of greater than 100, 1000, 1 x 104, 1 x 105, 1 x 106, or 1 x 107, siemens per meter (at 20 °C). In some particular embodiments, it may be advantageous that such a material be non-ferromagnetic (e.g. aluminum, copper, brass, etc.) in addition to being electrically conductive, as discussed in detail later herein. If pawl-support plate 70 (or, in particular, pawl-support post 74) is a separately -made item from drum 90, it may be made of any material with suitable properties, e.g. steel (noting that the presence of a ferromagnetic, e.g. steel, pawl-support post 74 may necessitate that the design of pawl 20 and / or biasing magnet 54 be adjusted to take into account the presence of the ferromagnetic post).

[0076] The above-discussed first and second threshold values of velocity that causes a pawl 20 to be actuated can be set as desired. Each velocity threshold may be set to any suitable nominal value, e.g. 4, 6, 8, 10, or 12 feet per second. Each such a nominal value will correspond to the linear velocity experienced by the extended portion of safety line 115 (and thus to a user connected thereto). This can be converted to an actual value of orbital velocity of pawl 20 in view of the specific design parameters of the fall-protection apparatus (e.g. the diameter of the drum from which the safety line is unwound, the diameter of the orbit of the pawl, and so on). This can be used to set particular parameters (e.g. the mass distribution of pawl 20, the strength, position and orientation of biasing magnet 54, and so on) to ensure that pawl 20 is actuated at first and second rotational velocities that correspond to the desired thresholds.

[0077] Similarly, the value of acceleration that modulates the velocity-response of a pawl 20 (i.e., that causes pawl-support plate 70 to rotate relative to drum 90) can be set as desired. It might seem that such a threshold should be set at 1.0 g (i.e., the nominal acceleration to which a falling user would be subjected). However, various factors (e.g. the presence of a motor spring that exerts a retracting force on the safety line, inertial and / or frictional effects of the various system components, the fact that an initial stage of a user fall might be at least slightly hindered by some object or structure, etc.) are such that it has usually been found appropriate to set the acceleration threshold at least slightly below 1.0 g. In various embodiments, such an acceleration threshold may be set to any suitable value, e.g. less than 0.95, 0.9, 0.8, 0.7, or 0.6 g. In further embodiments, such a threshold may be at least 0.5, 0.6, 0.7 or 0.8 g.

[0078] The above-described acceleration threshold is described in terms of the linear acceleration experienced by the extended portion of safety line 115 (and thus to a user connected thereto). This can be converted to an actual value of the threshold of rotational acceleration of pawl-support plate 70, in view of the specific design of the fall-protection apparatus. This can be used to set particular parameters (e.g. mass and mass distribution of the inertia disk, the strength, position and orientation of biasing magnet(s) 54, and so on, to ensure that inertia disk 40 rotates relative to pawl-support plate 70 (in order to modulate the velocity-response of pawl 20) at a predetermined rotational acceleration that corresponds to the desired threshold of acceleration experienced by the user. By way of a specific example, a rotationally-actuated braking device may be configured so that the one or more pawls of the device is / are actuated at a nominal user-falling velocity in the range of e.g. 8, 10, or 12 feet per second if the acceleration is relatively low (e.g., less than 0.7, 0.6 or 0.5 g) so that inertia disk 40 remains in its home position; and, so that the one or more pawls is / are actuated at a nominal user-falling velocity in the range of e.g. 4, 5, or 6 feet per second if the acceleration is sufficient (e.g., is at least 0.5, 0.6, 0.7, or 0.8 g or more) so that inertia disk 40 is rotated to its activated position.

[0079] Discovery of the source of a problem

[0080] Conventional rotationally-activated braking devices as used e.g. in fall-protection apparatus such as self-retracting lifelines, have historically relied on the braking device being activated by way of a drum (upon which a safety line of the apparatus is wound) exceeding a prechosen threshold rotational velocity, with acceleration not playing any significant role. However, it is theoretically possible to use some combination of rotational velocity and rotational acceleration to activate a braking device. The arrangement discussed above (configuring a braking device to include an inertia disk such that if a higher rotational acceleration is experienced, the threshold rotational velocity that is needed in order to activate the braking device is lowered) is one such possible approach. Various arrangements that contemplate the use of rotational acceleration and rotational velocity (whether independently or in combination) as the basis for activating a braking device are disclosed e.g. in U.S. Patents 10953848, 11759662, 11779783, 11779784, and 11878651.

[0081] Investigations by the applicant have revealed that approaches that rely on using rotational acceleration to modulate the response to rotational velocity are susceptible to a problem that can prevent such approaches from being used to their full advantage. The problem is as follows. In ordinary use of a fall-protection apparatus such as a self-retracting lifeline, there will be slight inhomogeneities in how successive windings of the cable (safety line) are wrapped on the drum-spool and on underlying windings of the cable on the spool. When the cable unwinds rapidly from the drum (e.g. in the event of a user fall), the effective radius of the rotating item (the remaining portion of cable that has not yet unwound from the dmm) will experience occasional, small perturbations due to the slight winding inhomogeneities. (The cable-wrapped drum will of course also undergo an overall reduction in effective radius as the unwinding of the cable progresses.)

[0082] The tangential velocity of a rotating item being proportional to its radius, these variations in the effective radius of the rotating item (the cable-wrapped dmm) can cause fluctuations in the rotational velocity of the cable-wrapped drum. In other words, even if a user is falling at a relatively constant linear velocity, the rotational velocity of the cable-wrapped drum to which the user is connected may vary in somewhat “herky-jerky” fashion. (This hypothetical example is presented purely for purposes of illustration, noting that in any real-life fall event, the fall is typically arrested long before the user approaches a constant falling speed.) Such phenomena typically manifest as short-time-scale fluctuations in the rotational velocity of the drum upon which the cable is wound. For example, as a drum undergoes accelerated rotation in the event of a user fall, the rotational velocity of the drum may not necessarily increase in a smooth manner as dictated by the gravitationally -induced acceleration; rather, it may exhibit high-frequency noise e.g. in the form of short-duration spikes and / or valleys that are superimposed on the overall acceleration curve.

[0083] With conventional self-retracting lifelines that rely on a drum’s rotational velocity exceeding a velocity threshold that is relatively constant (i.e. , unaffected by rotational acceleration) in order to activate a braking device, such phenomena seem to have been of little consequence and do not seem to have been noted in the art. That is, for such apparatus, in the event of a fall the drum will typically accelerate to reach the velocity threshold with little effect of any slight fluctuations that may occur along the way.

[0084] However, the present investigations have revealed that if it is attempted to use rotational acceleration to modulate the velocity -response of a braking device, a problem can occur. Specifically, if it is attempted to use rotational acceleration to purposefully alter the rotational velocity threshold of a braking device, the above-described perturbations, variations, etc., may affect the consistency and reproducibility of the braking device’s functioning. In particular, since acceleration is the derivative of velocity, small- scale fluctuations in rotational velocity can translate to large fluctuations in rotational acceleration. Such large fluctuations in the rotational acceleration experienced by a cable-wrapped drum can affect the threshold rotational velocity at which the braking device is activated to arrest the rotation of the drum. The present investigations have thus revealed a problem in the form of occasional inconsistency in the behavior of acceleration-modulated braking devices when performing a fall-arrest. While the problem does not necessarily preclude acceleration-modulated braking devices from being successfully used, the present investigations have indicated that solving the problem can significantly enhance the performance of at least some acceleration-modulated braking devices.

[0085] In summary, the source of the problem, as discussed above, is that in an acceleration-modulated braking device, the effects of small inhomogeneities in cable-wrapping are amplified: the rotational velocity is proportional to the effective radius of a rotating item, and the rotational acceleration of an item is the derivative of the rotational velocity of the item. Neither the fact that acceleration-modulated braking devices exhibit this problem (e.g. in the form of inconsistency in braking performance), nor the source of this problem, appear to have been disclosed or even recognized in the art.

[0086] With the above-described problem having been recognized and its source identified as discussed above, applicant has formulated arrangements that can largely mitigate, or even substantially eliminate, the problem. As outlined above, the basic problem is that an acceleration-modulated braking device is very sensitive to perturbations in the rotational velocity of a drum caused by fluctuations in how the cable unwinds from the drum (which, in turn, arises from inhomogeneities in how the cable was wound upon the drum). In the course of extensive investigations, the applicant has discovered that such perturbations are typically manifested as high-frequency noise. That is, each such perturbation (i.e., each such “spike” or “valley” in the rotational velocity of a rotating cable-wound drum) typically occurs over a very short time scale (e.g., less than 0.02 seconds; in comparison, a fall / arrest typically occurs over a relatively long time scale of e.g. 0.2 seconds or more).

[0087] With this realization, the applicant has found that configuring an acceleration-modulated braking device to exhibit the characteristics of a low-pass mechanical filter can allow the sensitivity of the braking device to such high-frequency noise to be substantially reduced. (The term “low-pass” is with respect to the frequency domain, and denotes an item, assembly, mechanism, device, arrangement, etc. that is relatively insensitive to events of short time duration, e.g. of less than 0.02 seconds in length.) In other words, an acceleration-modulated braking device can be formulated that still achieves the previously- discussed advantages of such braking devices (e.g., more rapid onset of braking, with commensurate reduction in fall-arrest distance), but with the braking device exhibiting enhanced consistency in fall-arrest performance. It is noted that the above-described cable-unwinding phenomena may not necessarily be the only source of high-frequency noise in a braking device (and / or in a fall-protection apparatus as a whole), although investigations so far indicate that in most circumstances it will be the primary source of high- frequency noise. Ordinary artisans will appreciate that the arrangements disclosed herein can reduce the sensitivity of a braking device, and / or of a fall-protection apparatus as a whole, to high-frequency noise from a variety of possible sources.

[0088] High moment of inertia pawls

[0089] The present investigations have revealed that one arrangement that can be beneficially brought to bear on the above-described problem is to configure the at least one pawl of such a braking device to have a high moment of inertia. Here and elsewhere herein, by moment of inertia is meant mass moment of inertia (also known as rotational inertia, and not to be confused with area moment of inertia), which is a scalar quantity obtained for a point mass by multiplying the mass by the square of the distance to the axis of rotation. For a non-point mass such as a pawl 20 as disclosed herein, the moment of inertia can be obtained as the sum of the moments of inertia of the component masses of the pawl (as can be calculated e.g. by CAD software). In the present usage, this moment of inertia will be with respect to pivotable movement of a pawl 20 around its pivot axis Pap.

[0090] The present investigations have revealed that providing a pawl with a relatively high moment of inertia can reduce the sensitivity of the pawl to short-term fluctuations in the rotational velocity of the drum, its associated pawl-support plate, and the pawl itself. In other words, while such short term fluctuations may still occur, the time scale of these events may be so short that the pawl may simply not respond to them due to the high moment of inertia of the pawl. It is emphasized that such an approach is not merely a further exploration of the concept of using acceleration to modulate the velocity -response of a braking device. That is, such an approach does not merely seek to further optimize the response to velocity and / or acceleration of such a device; rather, it takes into account the time scale over which events occur and provides a different dynamic response upon experiencing events of different time durations. The present investigations have indicated that for a fall-protection apparatus such as a selfretracting lifeline of a configuration as commonly used, for example, with a drum with a spool diameter of e.g. 2-6 inches, and with a safety line (e.g. a steel cable) of e.g. 3 / 16 to 7 / 32 inch in diameter (or equivalent diameter in the case of a non-circular-cross-section lifeline) and with a length of e.g. from 10-150 feet, a pawl that exhibits a moment of inertia of at least 130 g-cm2(in cgs units) can provide significant benefits in addressing and overcoming the above-discussed problem. A pawl that exhibits a moment of inertia of at least 130 g-cm2is thus defined herein as a high-moment-of-inertia pawl.

[0091] By way of a specific example, the exemplary prototype pawls as shown in the Figures herein were made of (martensitic) stainless steel and exhibited a mass of approximately 75 grams, and exhibited a moment of inertia of approximately 237 g-cm2. This moment of inertia is compared to those of pawls of braking devices of representative self-retracting lifelines in the art, in Table 1. In Table 1, Comparative Example (CE) 1 is the pawl used in the NANO-LOK self-retracting lifeline available from 3M Fall Protection; pawls of this type are also disclosed in U.S. Patent 9488235. Comparative Example CE-2 is the pawl used in the TALON self-retracting lifeline available from 3M Fall Protection. Comparative Example CE-3 is the pawl used in the SEALED-BLOK self-retracting lifeline available from 3M Fall Protection; pawls of this type are also disclosed in U.S. Patents 8567562 and 9925400. Comparative Example CE-4 is the pawl used in the SMART-LOCK and ULTRA-LOK self-retracting lifelines available from 3M Fall Protection; pawls of this type are also disclosed in U.S. Patents 9764172 and 11504557. Comparative Example CE-5 is the pawl used in the PROTECTA (REBEL) self-retracting lifeline available from 3M Fall Protection; pawls of this type are also disclosed in U.S. Patent 11779783.

[0092] Table 1

[0093] It is evident from Table 1 that the exemplary high-moment-of-inertia pawls disclosed herein comprise a moment of inertia that is significantly larger than that of representative pawls heretofore disclosed in the art. It is noted that none of the above-cited patents, and indeed no prior art document of which the applicant is currently aware, actually disclosed the moments of inertia of any prior art pawls (the moments of inertia of these representative prior art pawls were calculated by the applicant.) Nor has any known source disclosed that the moment of inertia of a pawl has been found to be a result-effective design parameter, whether in the general case of a conventional velocity -actuated pawl, or in the particular case of a pawl that is configured so that its velocity -actuation can be modulated based on acceleration experienced by some other item of the braking device that the pawl is used in. In fact, to the extent that the moment of inertia of pawls of rotationally -activated braking devices has been considered at all, it appears that ordinary artisans have conventionally endeavored to keep it as low as possible in view of practical considerations such as size, weight and cost.

[0094] In various embodiments, a high-moment-of-inertia pawl of the general type disclosed herein may exhibit a moment of inertia of at least 150, 170, 190, 210, or 230 g-cm2; in further embodiments, such a pawl may exhibit a moment of inertia of at most 400, 350, 300, or 250 gm-cm2. A presently preferred range is from 200 to 250 g-cm2; however, it will be understood that an optimum range of moment of inertia may depend on the design of any particular braking device.

[0095] Ballast element

[0096] Configuring a pawl to have a high moment of inertia is not a mere matter of increasing the overall mass of the pawl; rather, the mass distribution of the pawl must be properly configured. The applicant has found that a pawl of the general type depicted in Figs. 10a and 10b can be particularly advantageous. Specifically, the desire is to increase the moment of inertia of the pawl without unacceptably increasing the “footprint” of the pawl (i.e. , the radial / circumfcrcntial area that the pawl occupies when viewed along the axial direction “a” of the braking device, e.g. as viewed in Figs. 6-8). This desire is in view of the limited radial / circumferential space that is typically available within the housing of a fall-protection apparatus such as a self-retracting lifeline. In the depicted embodiment, pawl 20 comprises a main body 21 that comprises a leading portion 25 and a trailing section 37. Pawl 20 comprises a ballast element 26 that extends at least generally axially (that is, along the axial direction “a” of the braking device) from leading portion 25 of pawl 20. Leading portion 25 and ballast element 26 thus constitute leading section 24 of pawl 20, with the demarcation between ballast element 26 and leading portion 25 being indicated by dashed line 27. Thus according to the terminology herein, pawl 20 is comprised of main body 21 (comprising leading portion 25 and trailing section 37) along with ballast element 26 that extends axially from leading portion 25 of main body 21.

[0097] Ballast element 26 may be a separately -made item that is attached to leading portion 25; or, in many convenient embodiments, ballast element 26 may be integral with leading portion 25 and with the entirety of pawl 20. Ballast element 26 advantageously allows the inclusion of a large amount of mass in the leading section 24 of pawl 20 so that the desired high moment of inertia of pawl 20 may be achieved. This substantial amount of mass in the leading section 24 of pawl 20 also advantageously provides a large amount of ferromagnetic material for biasing magnet 54 to exert an attractive magnetic force on, so that the desired biasing force on pawl 20 (as well as on inertia disk 40) can be achieved. All this can be done while preserving an overall center of mass 34 of the pawl that is suitable for velocity -actuation of the pawl, and without unacceptably increasing the total footprint of the pawl.

[0098] In various embodiments a ballast element 26 (or, a set of multiple ballast elements) may provide at least 20, 25, 30, or 35 % of the total mass of pawl 20. In further embodiments, a ballast element 26 or set thereof may provide at most 60, 50, 45, or 40 % of the total mass of pawl 20. By way of a specific example, ballast element 26 of exemplary prototype pawl 20 as depicted in Figs. 10a and 10b, provides approximately 37 % of the total mass of pawl 20. The herein-disclosed ballast element 26 may be contrasted with generally axially -extending features as present on the pawls disclosed in U. S. Patent 11779783 (the generally axially- extending features of the pawls of the ‘783 patent are most easily visible in Fig. 5 of the ‘783 patent). Each generally axially-extending feature of each pawl of the ‘783 patent provides approximately 16 % of the total mass of the pawl. It is noted that the generally axially-extending features of the pawls of the ‘783 patent are not disclosed (in the ‘783 patent or elsewhere) as serving any particular purpose or providing any particular benefit.

[0099] The presence of ballast element 26 does require additional empty volume to be present to accommodate ballast element 26, in the axial direction. In the depicted embodiment, this is achieved by providing pawl-support plate 70 with a cavity 75 (most easily seen in Figs. 3 and 5). Cavity 75 is axially recessed relative to major surface 73 of pawl-support plate 70, and is axially -open-ended, both as evident from Fig. 3. Cavity 75 is configured to accommodate ballast element 26 of pawl 20 therein, and to allow pawl 20 to move between the disengaged position and engaged position without hindrance from the presence of ballast element 26. In the depicted embodiment, cavity 75 is partially defined by a surface 76 (indicated in Fig. 3) that serves as a first pawl-contacting surface with which a first contact surface 31 of ballast element 26 of pawl 20 is in contact, when pawl 20 is in the disengaged position. In other words, the disengaged position of pawl 20 is dictated by the contact of first pawl-contacting surface 76 of cavity 75 with first contact surface 31 of ballast element 26 of leading section 24 of pawl 20 (as denoted for the upper pawl in Fig. 6), whereas the engaged position of pawl 20 is dictated by the contact of second pawlcontacting surface 81 of buttress 80 with second contact surface 32 of trailing section 37 of pawl 20 (as denoted for the lower pawl in Fig. 8).

[0100] Inertia disk

[0101] The above discussions reveal that the mass moment of inertia of a velocity -actuated pawl is a resulteffective parameter that can be manipulated to decrease the sensitivity of a braking device to high-frequency noise such as from perturbations in the rotational velocity of a cable-drum with which the braking device operates. The mass moment of inertia of inertia disk 40 may also have an effect, and can be configured to further enhance the effects disclosed herein. Indeed, the numerous holes (unnumbered), that are visible in main body 41 of exemplary inertia disk 40 as visible in Figs. 5 and 9, were included so that the overall mass, and mass moment of inertia in particular, of this exemplary prototype inertia disk 40 could be established, modified, and so on, by the insertion of weights into the various holes. Numerous values of the mass and moment of inertia of this prototype disk were experimentally evaluated. In general, an inertia disk may comprise a mass of from e.g. 250 g to 500 g. In various embodiments, such an inertia disk may exhibit a moment of inertia (including the contributions from any biasing magnet 54 if present, and / or the contributions from any damping magnet 55 if present (damping magnet 55 is visible e.g. in Fig. 9 and is discussed in detail below)), of from at least 4000, 6000 or 8000 g-cm2, to at most 15000, 13000, or 11000 g-cm2(noting that the relevant moment of inertia of inertia disk 40 is relative to the axis of rotation Raof the inertia disk 40, drum 90, etc., whereas the relevant moment of inertia of pawl 20 is relative to the pivot axis Papof pawl 20 as discussed above.) A presently preferred range of moment of inertia of an inertia disk is 8000-10000 g-cm2; however, it will be understood that an optimum range of moment of inertia may depend on the design of any particular braking device.

[0102] In some embodiments, inertia disk 40 may comprise a main body 41 that is made of any suitable material, along with any other items as may be mounted on or partially within main body 41. (For example, one or more small weights may be attached to the main body, e.g. during the process of manufacturing the braking device, to fine-tune the properties of the inertia disk.) In some embodiments, main body 41 may be a metal or metal alloy (e.g. aluminum, brass, steel, etc.). If main body 41 is made of a ferromagnetic material, any effect of this on biasing magnet(s) 54 may need to be taken into account. However, the material of main body 41 may have little effect on any damping magnet(s) 55 since damping magnet(s) 55 will not move relative to main body 41, as discussed in detail below. In some embodiments, main body 41 may be made of a suitable organic polymeric material, e.g. an engineering polymer comprising one or more reinforcing agents such as inorganic fillers, carbon fibers, and so on. A biasing magnet 54 and / or a damping magnet 55 may be securely mounted on (or, within or partially within) main body 41 in any suitable way, e.g. by the use of an adhesive, one or more set screws, etc. In some embodiments, such a magnet may be placed in a receptacle provided within main body 41; in some such cases the main body may comprise at least one interference feature (e.g. a lip or flange that at least partially covers the receptacle) positioned outwardly of the magnet, to securely retain the magnet in the receptacle.

[0103] Damped inertia disk

[0104] The present investigations have revealed another approach that allows the performance of an acceleration-modulated braking device to be enhanced. Specifically, inertia disk 40 can be damped. By this is meant that inertia disk 40 can be arranged so that motion of inertia disk 40 towards its activated position; and, motion of inertia disk 40 towards its home position, are opposed by a damping force. The damping of an item, e.g. an inertia disk 40, is thus distinguished from the previously-described biasing, which is specifically limited to providing a force that opposes the movement of an item in one direction, but not in a second, opposing direction.

[0105] It will be appreciated that any real item, e.g. inertia disk 40, will be inertially damped to at least some extent by virtue of its mass. That is, when inertia disk 40 is stationary, the mass of inertia disk 40 will tend to oppose rotation in either direction. However, beyond this, the present arrangements contemplate the active damping of inertia disk 40. By active damping is meant an arrangement that relies on a force that develops on inertia disk 40 only by virtue of inertia disk 40 being in motion, and that is not present when inertia disk 40 is stationary. (This requirement is with regard to movement of inertia disk 40 relative to pawl-support plate 70, noting that often, the entire braking assembly may be rotating during ordinary use of the fall-protection apparatus as discussed earlier.)

[0106] In some embodiments, inertia disk 40 can be actively damped by way of being magnetically damped. In the illustrated embodiment, this is achieved by way of mounting at least one (in the depicted embodiment, two) damping magnets 55 on major side 44 of inertia disk 40. Major side 44, and thus damping magnets 55, face toward pawl-support plate 70, with damping magnets 55 being axially-oriented e.g. as shown in Fig. 4, so that their zone of maximum electromagnetic field extends axially so as to penetrate into the body of pawl-support plate 70. (No such damping magnets may be needed on opposing major axial side 43 of inertia disk 40, which faces away from pawl-support plate 70.) Pawl-support plate 70 may be comprised of material (whether a single, solid material such as e.g. aluminum, or a suitable composite) that is not ferromagnetic (so that damping magnets 55 do not exert any significant magnetic force on pawlsupport plate 70) but that is electrically conductive.

[0107] Damping magnets 55 being fixed to inertia disk 40, any movement of inertia disk 40 (and thus of magnets 55) relative to pawl-support plate 70, such as will happen when inertia disk moves from a home position toward an activated position (or vice versa), will generate eddy currents in the conductive body of pawl-support plate 70. (Depending on the particular arrangement, some eddy currents may also be generated in the body of drum 90, e.g. in near sidewall 94 thereof, which may further contribute to the effects described herein.) These eddy currents will in turn generate an electromagnetic field (in accordance with Lenz’s law) that will act to oppose the motion of damping magnets 55, and thus of inertia disk 40. This will be true regardless of which direction inertia disk 40 is rotating, thus this is a true (bidirectional) damping force and not a biasing force. Magnetic damping as achieved via eddy current braking is thus distinguished from magnetic biasing as described earlier herein.

[0108] By way of such arrangements, inertia disk 40 may be subjected to active damping. The present investigations have found that the application of active damping forces to inertia disk 40 can contribute to the effects disclosed herein, e.g. to reducing the sensitivity of an acceleration-modulated braking device to high-frequency noise. While, in some embodiments, the active damping of inertia disk 40 may be used in combination with other arrangements (e.g. the use of one or more pawls with a high moment of inertia), the benefits of active damping of an item such as an inertia disk is independent of such other arrangements. A damping magnet 55 can be positioned at any suitable distance from major axial surface 73 of pawl-support plate 70 that allows the above-described magnetic damping to operate. Such a distance will be the distance of closest approach between damping magnet 55 and any point on major axial surface 73. In various embodiments, such a distance may be less than 6.0, 4.0, or 2.0 mm. In further embodiments, such a distance may be greater than 0.5, 1.0, or 1.5 mm.

[0109] Other damping mechanisms may be envisioned, subject to the limitation that any such damping must act to oppose motion of an inertia disk (or whatever item is to be damped) in a first direction and in a second, opposing direction, as discussed above. One possible arrangement is frictional damping, as achieved e.g. by the presence of a frictional-damping entity that has a suitable frictional surface that will oppose the motion of inertia disk 40. Such a frictional surface of a frictional-damping entity may be e.g. in axial contact with a major axial face of inertia disk 40 (e.g. it might take the form of a friction disk that axially abuts inertia disk 40); or, it might be in radial contact with inertia disk 40 (e.g., it might take the form of a “sleeve” positioned radially within central aperture 42 of inertia disk 40). Any such frictional- damping entity may be arranged so that it is in fixed rotational relation with pawl-support plate 70, so that if inertia disk 40 does begin to rotate relative to pawl-support plate 70, inertia disk 40 will thus rotate relative to the frictional-damping entity, so that the rotation of inertia disk 40 is opposed by the frictional force developed by the frictional surface of the friction-damping entity. An arrangement in which an inertia disk is bidirectionally frictionally damped will be distinguished from, e.g., the use of unidirectional friction brakes that bring a rotating dmm (and / or its associated pawl-support plate, etc.) to a stop in the manner described later herein.

[0110] A frictional damping mechanism will be considered herein to be a “passive” damping mechanism, since frictional forces will be present when the inertia disk is not moving relative to the frictional-damping entity. (In fact, the coefficient of static friction often being higher than the coefficient of kinetic (sliding) friction, the damping force may often be highest when no relative movement is present.)

[0111] Three damping approaches have thus been outlined herein: active damping such as magnetic damping (that relies on eddy current phenomena); passive damping in the form of frictional damping; and, passive damping in the form of inertial damping as provided by the mass of an item itself. In various embodiments, any such approach or combination thereof may be used (noting that inertial damping will always be present at least to some extent). However, the present investigations have so far found magnetic damping to be preferable, at least in part because the magnetic damping force advantageously increases with the relative velocity of the damping magnet(s) and the item in which eddy currents are induced (in other words, the magnetic damping force increases with the rotational velocity of the inertia disk relative to the pawl-support plate). In contrast, any frictional-damping force will likely stay constant (or may even decrease somewhat) with increased velocity; similarly, inertial damping purely due to the mass of an item will typically exhibit a constant damping force regardless of the velocity. Magnetic damping thus appears ideally suited as an active damping approach that serves to bidirectionally reduce the velocity, and / or the total magnitude, of rotation of the inertia disk relative to the pawl-support plate.

[0112] In some embodiments, an inertia disk may only be able to rotate to a limited extent (e.g. 15 degrees) relative to the pawl-support plate, as discussed in detail earlier herein. Arrangements in the art that use eddy current forces e.g. forbraking of a rotating entity are typically configured to operate over the course of one or more (often, numerous) full rotations of the entity relative to another item. In the present arrangements, eddy current forces have been found to be sufficient to achieve the objectives disclosed herein (bidirectional damping), notwithstanding the fact that there may be only a relatively small movement of the inertia disk relative to the pawl-support plate.

[0113] Thus as disclosed herein, in some embodiments an inertia disk may be magnetically biased e.g. by way of one or more biasing magnets 54, and / or may be magnetically damped e.g. by way of one or more damping magnets 55. In some embodiments, such effects may be largely independent of each other. For example, the damping magnet(s) may not significantly affect the biasing forces developed by the biasing magnet(s). Similarly, the biasing magnet(s) may not significantly affect the damping forces developed by the damping magnet(s), other than the obvious fact that the amount that the biasing magnet(s) allows the inertia disk to move will affect the ability of any damping force to develop; e.g., no damping force will be developed if, in a particular situation, the biasing magnet(s) prevent the inertia disk from moving at all.

[0114] Any such arrangements may be achieved e.g. by way of the physical location and geometric orientation of the magnet(s), e.g. in combination with the particular magnetic properties, shape, etc. of the magnet(s). In some embodiments, each biasing magnet that is on an inertia disk 40 may be spaced apart from each damping magnet that is on the inertia disk 40, by which is meant that they are at least 2 cm apart at their point of closest approach (in the exemplary inertia disk 40 shown in the Figures herein, each biasing magnet 54 is spaced 3.2 mm from the closest damping magnet 55). In various embodiments, a biasing magnet and a damping magnet may be spaced from 2.5, 3.0, or 3.5, to 6.0, 5.0, or 4.0, cm apart.

[0115] In various embodiments, a biasing magnet and / or a damping magnet may be a permanent magnet chosen e.g. from rare-earth materials and alloys thereof, such as e.g. neodymium (typically alloyed with iron and boron), samarium-cobalt, and so on. Any such magnet may be used e.g. in a “button” geometry (as with magnets 55 as visible in Fig. 9), or in an elongate “cylinder” or “bar” format (magnets 54 are of this type, noting that only the radially outward faces of magnets 54 are visible in the Figures herein). In many embodiments, a biasing magnet 54 may be radially -oriented so that its zone of maximum magnetic force extends generally radially outward toward leading section 24 of pawl 20; and, a damping magnet 55 may be axially -oriented so that its zone of maximum electromagnetic field extends generally axially, toward pawl-support plate 70.

[0116] Multiple concepts are disclosed herein, including but not limited to : the use of one or more damping magnets to bidirectionally damp the motion of an inertia disk; the co-biasing of a pawl and an inertia disk by a common biasing magnet that is performing “double-duty”; and, the use of a pawl with a high moment of inertia (e.g., in particular, doing this by providing the pawl with an axially-extending ballast element, and providing a pawl-support plate with a cavity to accommodate such a ballast element). While in some presently preferred embodiments, all of these concepts may be used in combination, it is emphasized that all of these concepts are independent; therefore, any or all such concepts may be used alone, or in any combination with any other such concept.

[0117] In fall-protection apparatus such as self-retracting lifelines, it has been, and is, considered very important to provide a short fall-arrest distance. This being the case, various concepts disclosed herein, e.g. using pawls that are large and / or heavy so as to have a high mass moment of inertia, and / or using an inertia disk that is damped, would conventionally be avoided because they would be expected to make the braking device slow to respond. However, the present investigations have revealed that such arrangements, by enabling an acceleration-modulated braking device to be less sensitive to high-frequency noise, can allow such a braking device to have velocity-actuated pawls whose velocity-actuation is highly modulated by acceleration so that the braking device is able to respond to an actual user fall very quickly and thus provide a short fall-arrest distance. This can be achieved without subjecting a user to unacceptably high fall-arrest forces and without rendering the braking device unacceptably susceptible to, e.g., nuisance lockups during the course of ordinary activities. Numerous variations of the above concepts and combinations are possible. For example, in some embodiments inertia disk 40 could be biased by way of one or more mechanical springs (e.g. coil spring, torsion spring, etc.), operating in compression or in tension. Such biasing might augment, or be used in place of, the previously-discussed biasing of inertia disk 40 by way of biasing magnet 54. In fact, the prototype inertia disk 40 shown in the Figures herein includes an aperture (numbered 59 in inertia disk 40 in Fig. 5) to allow, if desired, a coil spring to be seated in shoulder 51 of inertia disk 40. Such a coil spring, acting in compression (e.g. with its opposing end abutted against surface 84 of buttress 80) would act to bias inertia disk 40 towards its home position. It is noted that while it is possible to bias inertia disk 40 with one or more springs, it might be difficult to bidirectionally damp inertia disk 40 with conventional springs, since a conventional spring (e.g., a coil spring acting in tension or in compression, a torsion spring, etc.) typically exhibits little dissipative energy loss and thus would not be expected to provide significant damping of an item (e.g. an inertia disk) to which the spring(s) is / are coupled.

[0118] In some embodiments, pawl 20 could be biased by way of one or more mechanical springs, operating in compression or in tension. Such biasing might augment, or be used in place of, the previously- discussed biasing of pawl 20 by way of biasing magnet 54. In fact, the prototype pawl 20 shown in the Figures herein includes an aperture (numbered 39 in pawl 20 in Fig. 5) to allow, if desired, a coil spring to be seated in leading section 24 of pawl 20. Such a coil spring, acting in compression, would act to bias pawl 20 toward its home position. (In order to have a surface for the opposing end of such a spring to abut against, the radially outward end of cavity 75 of pawl-support plate 70 would need to have a radially -inward-facing boss or wall rather than being fully radially -outwardly-open-ended as in the exemplary arrangements shown in the Figures herein.) In various embodiments, any such arrangements may be used, and further variations are possible (e.g. using springs acting in tension rather than acting in compression.)

[0119] Other variations are possible. For example, in some embodiments a biasing magnet might be mounted on a pawl, whether in addition to, or in place of, a previously -described biasing magnet that is mounted on inertia disk 40. With such an arrangement, at least a local area of an entity (e.g., an inertia disk or a pawl-support plate) in close proximity to such a pawl-mounted magnet may include a sufficient mass of ferromagnetic metal so that the pawl can exert a sufficient attractive force thereon. Or, a complementary biasing magnet may be mounted in such a local area, e.g. with the pawl-mounted magnet and the complementary biasing magnet being oriented to exhibit an attractive force therebetween, that serves to bias the pawl towards its disengaged position and / or to bias the inertia disk toward its home position. Conversely, a pair of magnets might be oriented oppositely (so as to exert a repelling force therebetween), but with the locations of the magnets chosen so that the repelling force causes the magnets to bias the pawl toward its disengaged position and / or to bias the inertia disk toward its home position.

[0120] Similarly, the location of any damping magnets may be varied. For example, in some embodiments one or more damping magnets could be mounted on axial side 43 of inertia disk 40 rather than being mounted on the pawl-support-plate-facing axial side 44 of inertia disk 40 as described earlier herein. Such damping magnets could be used in combination with, e.g., a dedicated damping disk that is made of a suitably conductive material and is positioned so that the damping magnets on axial face 43 of the inertia disk will cause eddy currents in the damping disk upon movement of the damping magnets relative to the damping disk. The damping disk can be configured so that it is in fixed rotational relation with the pawlsupport plate (e.g. by being keyed to shaft 97). With such an arrangement, any lag-rotation of the inertia disk relative to the pawl-support plate in the general manner discussed earlier herein, will similarly cause the inertia disk to lag-rotate relative to the damping disk, thus causing eddy current forces which will damp the movement of the inertia disk.

[0121] In further possible variations, an inertia disk 40 and pawl(s) 20 may be biased separately and independently, e.g. by separate biasing magnets, by separate biasing springs, or by any combination of magnet(s) and spring(s), rather than being co-biased in the manner described earlier herein. In a more general sense, any of the herein-disclosed concepts may be used in braking devices that are arranged at least somewhat differently from the exemplary devices disclosed herein. For example, U.S. Patent 11779783 discloses a braking device in which one or more pawls is mounted on a pawl-support plate that is rotatable relative to a drum, but is biased into a first position. Each pawl is biased by a biasing spring whose other end is connected to the drum rather than to the pawl-support disk. Sufficient rotational acceleration will overcome the biasing of the pawl-support plate and cause the pawl-support plate to lag-rotate relative to the drum. This will change the length of the pawl-biasing spring thus modulating the response of the pawl to velocity as discussed in detail in the ‘783 patent. Various of the herein-disclosed approaches may be incorporated into a braking device of the general type described in the ‘783 patent. For example, high- moment-of-inertia pawls of the general type disclosed herein may be used in the ‘783 braking device, any such pawls may be equipped with a ballast element, and so on. Another possibility is to include one or more damping magnets in the pawl-support plate of the ‘783 braking device to cause eddy currents in the drum (in such a case, the drum would need to be made of, or include, a sufficient amount of an electrically- conductive material) so as to damp motion of the pawl-support plate relative to the drum. Conversely, one or more damping magnets could be mounted e.g. in the sidewall of the drum of the ‘783 braking device, that would cause eddy currents in the pawl-support plate (which would need to be made of, or include, a sufficient amount of a conductive material) so as to damp motion of the pawl-support plate relative to the dmm. U.S. Patent 11779783 is incorporated by reference herein in its entirety in specific regard to combining one or more of the herein-disclosed concepts with any arrangement of the ‘783 braking device so as to provide the ‘783 braking device with enhanced low-pass filtering capability.

[0122] Self-unlocking and motor-spring-assisted-unlocking configurations

[0123] Although discussions herein have focused on activation of a braking device in the event of a user fall, in actuality, the vast majority of activations of such braking devices are in the form of lock-up tests performed e.g. by the user of a fall-protection apparatus such as a self-retracting lifeline. Such lock-up tests are performed periodically to check that the apparatus is functioning properly, and typically involve grasping the safety line (cable) of the apparatus and giving it a sharp pull in a direction away from the housing of the apparatus. This causes the drum to rotate in the unwinding direction at a sufficient speed and / or acceleration to cause one or more pawls to engage a ratchet tooth. The cable is thus brought to a quick halt thus confirming that the braking device of the apparatus appears to be in good working order.

[0124] A somewhat underappreciated issue with such fall-protection apparatus is that the braking device must be able to unlock at the conclusion of the test. That is, upon the cessation of the unwinding force on the safety line, the pawl(s) must leave their engaged position and return to their disengaged position so that the braking device is ready for further use. In the herein-disclosed apparatus, the inertia disk must likewise return from the activated position to its home position.

[0125] In some embodiments, a braking device as disclosed herein may be self-unlocking. By this is meant the following. With the inertia disk in its activated position and with the pawl(s) in its engaged position, the zone of highest magnetic force of the biasing magnet 54 is circumferentially offset from the leading section 24 of pawl 20. That is, in such circumstances the biasing magnet 54 will be located e.g. generally radially inward of the pivot axis Papof the pawl (as in Fig. 8), rather than being located generally radially inward of, and / or closely abutting, the center of mass 35 of the leading section 24 of the pawl, as is the case when the inertia disk is in its home position and the pawls is in its disengaged position. Also, with the pawl in the engaged position the leading section 24 of the pawl will be displaced radially outward from biasing magnet 54, also as evident in Fig. 8. The magnetic force that magnet 54 exerts on leading section 24 of pawl 20 will thus be sharply reduced, as discussed earlier herein.

[0126] Nevertheless, in some embodiments there may be sufficient magnetic attraction between the leading section 24 of pawl 20 and biasing magnet 54, that once any unwinding force on the drum (which would tend to keep pawl 20 engaged with a ratchet tooth) has been reduced so that there is no substantial net unwinding force (for the purposes herein, this can be defined as less than 5 N), inertia disk 40 will begin to rotate away from its activated position toward its home position, and / or pawl 20 will begin to pivot away from its engaged position toward its disengaged position, as urged by biasing magnet 54. Such a process, once it commences, may be auto-accelerating in that as the movement of pawl 20 and / or of inertia disk 40 continues, the magnetic force between biasing magnet 54 and the leading section 24 of pawl 20 rapidly increases thus further promoting the movement. An arrangement of this type, in which the pawls and the inertia disk are configured to be able to respectively return from their engaged / activated positions due solely to the unassisted biasing force of the biasing magnet, will be referred to as the braking device being selfunlocking.

[0127] In other embodiments, such a braking device may not necessarily be self-unlocking. However, such a braking device can still be returned to a ready position (in which the pawl(s) are in a disengaged position and the inertia disk is in its home position) according to the following arrangement. As noted earlier herein, in many embodiments a fall-protection apparatus such as a self-retracting lifeline will include a motor spring that biases the drum to rotate to retract the safety line and wind it on the drum. Although the primary purpose of such a motor spring has historically been to enable the safety line to be retracted automatically as needed (hence the name self-retracting lifeline), in a braking device as disclosed herein a motor spring can serve an additional purpose. Specifically, once any unwinding force on the drum has been reduced so that the retracting force imparted by the motor spring exceeds the unwinding force, the force that the motor spring exerts on the drum can cause the drum, and thus the pawl-support plate, to begin to rotate in the winding direction. This will cause the pawls to move orbitally in the winding direction. The pawls, and the ratchet of the braking device, can be configured so that this retrograde orbital movement of the pawls causes a secondary contact surface 38 (indicated in Fig. 8) of a pawl 20 to contact a secondary pawl-contact surface 122 of the ratchet. As indicated in Fig. 2, a secondary pawl-contact surface 122 will be the gently-sloped “backside” of a ratchet tooth 121. This glancing-angle contact between surfaces 38 and 122 will urge the leading section 24 of the pawl 20 at least slightly radially inward. At this point, the force of biasing magnet 54 can take over and cause the pawl to continue to pivotably move into its disengaged position and cause the inertia disk to rotate into its home position in the general manner described above. The same can occur for any other pawl, although in some embodiments the rotation of the inertia disk toward its home position may be sufficient to increase the magnetic force between that pawl and its biasing magnet such that that pawl returns to a disengaged position without having contacted a secondary pawl-contact surface of the ratchet. This general arrangement will be referred to as a self-retracting lifeline comprising a motor-spring- assisted-unlocking configuration.

[0128] As noted, the arrangements herein cause at least one pawl to engage with a tooth 121 of a ratchet 120. This can either stop the rotation of drum 90 directly (and e.g. near-instantaneously, in the case of a “hard-stop” arrangement as mentioned earlier herein), or can activate a friction brake that brings the rotation of drum 90 to a halt. It will be appreciated that numerous variations of ratchets, and the manner in which one or more pawls engage with a tooth of the ratchet, are possible. For example, in the exemplary arrangements depicted in the Figures herein, the pawls are configured so that the engaging end 22 of a pawl 20 will travel from a disengaged position to an engaged position by moving generally radially outward. Such arrangements are typically used with a radially -inward-facing ratchet (meaning a ratchet with radially inward-facing teeth; e.g. a ratchet ring of the general type exemplified by ratchet 120 of Fig. 2 herein). However, in some embodiments a velocity -actuated pawl 20 may be configured so that the engaging end of the pawl travels from a disengaged position to an engaged position by moving generally radially inward rather than outward, as noted above. Such arrangements may be used with a ratchet (e.g. a ratchet ring or disc) that is radially -outward-facing; for example, a ratchet ring of the general type depicted as item 142 in Fig. 3 of U.S. Patent 11504557, which is incorporated by reference in its entirety herein.

[0129] In some embodiments a ratchet, rather than being provided e.g. as a toothed disk or ring that is made separately and inserted into a housing of a fall-protection apparatus, may be provided e.g. as an integral (e.g. molded, cast, or machined) feature of the housing of the apparatus. The PROTECTA REBEL fall-protection apparatus, available from 3M Fall Protection, Red Wing, MN, is an example of a product that uses this type of ratchet. Another possible variation in ratchet design is presented in U.S. Patent 9488235, in which a ratchet takes the form of a single tooth (“stop member”) that is provided as an integral part of a bracket (e.g., a load-bearing bracket) of a fall-protection apparatus. From the above discussions it will be clear that a ratchet of a rotationally -activated braking device can be any component (e.g. a toothed disk or ring or partial disk or partial ring, or a portion of a fallprotection bracket or housing) that includes at least one tooth that can be engaged by an engaging end of a pawl to initiate a braking operation of the rotationally -activated braking device. It is emphasized that the term “ratchet” is used for convenience of description; use of this term does not require that the ratchet and pawl(s) must necessarily be arranged e.g. so that relative rotation of these components is permitted in one direction but is precluded in the opposite direction. (However, the ratchet and pawl(s) can be arranged so that such functionality is provided if desired.)

[0130] In some embodiments a rotationally -activated braking device as disclosed herein can bring a drum to a “hard stop” (e.g. the braking device may rely on a ratchet that is non-rotatably fixed to the housing of the apparatus), as mentioned earlier herein. However, in other embodiments a rotationally-activated braking device as disclosed herein may comprise a friction brake. In general, a friction brake will comprise at least one layer of friction material and at least one rotatable member, with a friction-braking surface of the layer of friction material being in contact (typically, at all times during ordinary use of the fall-protection apparatus) with a contact surface of the rotatable member. By a rotatable member is meant an item (e.g., a disk, ring, rotor, or the like) that is configured so that the member and the layer of friction material can be set into rotating motion relative to each other upon sufficient differential torque being applied to the layer of friction material and the rotatable member as the result of the engaging of a pawl with a ratchet of the rotationally-activated braking device. In many embodiments, the friction-braking surface of the layer of friction-braking material and the contact surface of the rotatable member are constantly pressed together to provide sufficient static frictional force that, as a human user moves about a workplace in ordinary use of the apparatus, there is no relative motion between the two surfaces. However, upon the engaging of a pawl with a ratchet of the rotationally-activated braking device, sufficient differential torque is generated to overcome the static frictional force, such that relative motion of the two surfaces (and hence relative motion of the rotatable member and the layer of friction material) may occur. The rotatable member and the layer of friction material are configured so that this relative rotation of the layer of friction material and the rotatable member will be slowed and / or brought to a halt by the frictional forces between the frictionbraking surface of the layer of friction material and the contact surface of the rotatable member. The slowing / halting of this relative rotation will serve to slow / halt the rotation of a drum bearing a safety line.

[0131] The above is a general description of a friction brake and its function; many variations are possible. For example, in some embodiments, a rotationally -activated braking device may comprise a friction brake of the general type disclosed in the isolated exploded view of Fig. 3 of the above-mentioned U.S. Patent 11504557. It will be appreciated that the particular design depicted in Fig. 3 of the ‘557 patent is merely one example of a friction brake, in which two friction layers axially sandwich the rotatable member (which, in the ‘557 design, is the ratchet itself). Another exemplary friction brake is depicted in Fig. 4 of U.S. Patent 8430206; in the ‘206 friction brake, there is only a single friction layer. Another exemplary friction brake is depicted in Fig. 3 of U.S. Patent 9925400; in the ‘400 friction brake, there are two rotatable members, each rotatable member being axially sandwiched between a pair of friction layers.

[0132] In general, any combination of type and number of friction layers, and rotatable member(s) that are configured to be brought to a halt by the friction layer(s), can be used. A friction layer may use any suitable friction material, e.g. cork, rubber, and so on. Some friction materials that may be particularly useful are described in the above-referenced U.S. Patent 11504557. In general, any compatible type, design or arrangement of ratchet, rotatable member, friction material, and so on, may be used in combination with the herein-disclosed high-moment-of-inertia pawls, damped inertia disk, etc.

[0133] The exemplary arrangement depicted in the Figures herein relies on a shaft 97 (most easily seen in Fig. 2) that is rotatably mounted in the housing 111 of the apparatus, with drum 90 and pawl-support plate 70 being fixed to shaft 97 so that they cannot rotate relative to shaft 97 (rather, shaft 97, drum 90, and pawlsupport plate 70 will all rotate in unison). In other embodiments, any one, any subset, or all of the concepts disclosed herein may be used with an arrangement in which a shaft is fixed to a housing so that the shaft cannot rotate relative to the housing. In such an arrangement, drum 90 and pawl-support plate 70 may be rotatably mounted on the shaft so that both can rotate relative to the shaft; however, they may be configured so that they cannot rotate relative to each other. In some embodiments, this may be achieved by making pawl-support plate 70 an integral part of drum 90; however, in other embodiments, pawl-support plate 70 may be a separately-made item that is then attached to dmm 90 or is otherwise connected to drum 90, directly or indirectly, in such manner as to ensure that pawl-support plate 70 cannot rotate relative to drum 90. In such an arrangement, drum 90 and pawl-support plate 70 will rotate in unison while the shaft remains stationary.

[0134] In some embodiments, a fall-protection apparatus comprising any or all of the concepts disclosed herein, may comprise a housing 111, e.g. as formed by the assembling together of two major housing pieces 112 and 113, that is load-bearing. By an item being load-bearing is meant that the item is configured so that in the event of a user fall, the item bears the static load of the user’ s weight as well as bearing any temporary , dynamic forces that arise from arresting the user’s fall. By housing 111 being load-bearing is meant that in the event of a user fall, a load that is developed in arresting the fall travels through a force-transmitting pathway that substantially passes through housing 111. The housing pieces that collectively provide a loadbearing housing 111 may be formed of any suitable material(s), e.g. steel or aluminum. In some embodiments, such housing pieces may be made of organic polymeric materials, e.g. reinforced with fillers such as glass fiber, carbon fiber and the like. Load-bearing housings and materials that may be suitable for use in such housings are described in U.S. Patent 8430206, which is incorporated by reference herein in its entirety.

[0135] In some embodiments, a fall-protection apparatus comprising any or all of the concepts disclosed herein may comprise a housing 111 that is not load-bearing. In some embodiments, such an arrangement may rely on a load-bearing member (which may be variously referred to e.g. as a bracket, clevis, or stirrup) that is generally U-shaped with a drum-bearing shaft being installed in the gap between the “arms” of the U-shaped member. (A representative example of such a member is bracket 124 depicted in Fig. 1 of U.S. Patent 10792523.) In such a case, any load that develops is primarily transmitted via the load-bearing member, with the housing not bearing any substantial load but rather serving mainly to protect the internal components of the apparatus from rain, dirt, environmental hazards, and so on.

[0136] In some embodiments a fall-protection apparatus as disclosed herein may comprise a housing configured so that an interior compartment of the apparatus is at least partially sealed (such as in the product line available from 3M Fall Protection under the trade designation (SEALED-BLOK) e.g. for use in harsh or marine environments. In some embodiments, such a fall-protection apparatus may be configured in the general manner of those disclosed e.g. in U.S. Patents 9925400 and 10556138, which are incorporated by reference in their entirety herein. In general, such arrangements may involve configuring a housing to have two (or more) compartments separated by one or more seals, gaskets, partitions, or the like. A first compartment may contain items that are desired to be isolated from the outside environment (e.g., any or all of a pawl-support plate, one or more pawls, an inertia disk, a ratchet, and a friction brake assembly if present), and may be shielded, e.g. by the one or more seals, gaskets or partitions, from the second compartment and from the outside environment. A second compartment may include e.g. a drum with a safety line attached, along with any other items that do not necessarily need extra shielding from the outside environment; this second compartment will be open to the outside environment (e.g. by way of a through- aperture) at least to an extent necessary to allow the safety line to extend out of the second compartment.

[0137] The arrangements disclosed herein may be advantageously used in any fall-protection apparatus; in particular, in a self-retracting lifeline. In addition to the documents previously cited herein, fall-protection apparatus such as e.g. self-retracting lifelines in which the arrangements disclosed herein may be advantageously utilized, are described in U.S. Patents 8181744, 8256574, 8430206, 8430207, 8511434, 9488235, and 10556138. In general, the arrangements disclosed herein may be used in any fall-protection apparatus, e.g. self-retracting lifeline, in which there is a desire to enhance the performance of the apparatus in the general manner discussed herein.

[0138] In some embodiments such an apparatus may be a self-retracting lifeline that meets the requirements of ANSI Z359.14-2021 (as updated August 2023). In various embodiments, such a selfretracting lifeline may be an ANSI Z359.14 Class 1 device e.g. for use with an anchor point above the dorsal D-ring of the safety harness of a user; or, an ANSI Z359.14 Class 2 device e.g. for use with an anchor point above, at, or as much as five feet below the dorsal D-ring of the safety harness of a user (e.g., a “leading edge” rated apparatus). In some embodiments, such a self-retracting lifeline may comprise a housing that is e.g. attached to an anchorage and that comprises a safety line with a distal end (comprising e.g. a gated connector) that can be attached to a harness of a human user. In other embodiments, such a selfretracting lifeline may be a so-called “personal” self-retracting lifeline (e.g., that falls within ANSI Z359.14 category SRL-P), that comprises a housing that is attachable to a harness of a human user and that comprises a safety line with a distal end (comprising e.g. a gated connector) that can be attached e.g. to an anchorage. Personal self-retracting lifelines are exemplified by the product line available from 3M Fall Protection under the trade designation NANO-LOK. A fall-protection apparatus as described herein may comprise a housing, dmm, rotationally-activated braking device, etc., of any desired size. In some embodiments, the size of the rotationally -activated braking device may be characterized e.g. in terms of the diameter of the orbital path that is followed by the pivot axis (Pap) of the velocity -actuated pawl(s) 20, when viewed along the axial direction “a” of the braking device. In various embodiments, the diameter of such an orbital path may be at least 20, 30, 40, or 50 mm; in further embodiments, the diameter of such an orbital path may be at most 150, 120, 90, or 60 mm.

[0139] In various embodiments, a fall-protection apparatus as described herein may be used in concert with, or as part of, any suitable fall-protection system such as e.g. a horizontal lifeline or retractable horizontal lifeline, a positioning lanyard, a shock-absorbing lanyard, a rope adjuster or rope grab, a vertical safety system (such as e.g. a flexible cable, rigid rail, climb assist, or fixed ladder safety system), a confined- space rescue system, davit system or hoist system, and so on. In some embodiments, such a fall-protection apparatus may be installed on an aerial lift (e.g., an order picker, scissor lift, and so on).

[0140] It will be understood that any such fall-protection apparatus may include, or be used with, various ancillary items which are not described in detail herein. Such items may include, but are not limited to, one or more of lanyards, shock absorbers, tear strips, harnesses, belts, straps, paddings, tool holsters or pouches, impact indicators, carabiners, D-rings, anchorage connectors, and the like. Many such apparatus, products, and components are described in detail e.g. in the 3M DBI-SALA Full-Line Catalog (2022). Although in some embodiments it may not be necessary due to the presence of a friction brake, in some embodiments the safety line of the apparatus may comprise an in-line shock absorber e.g. of the type mentioned earlier herein. (Exemplary shock absorbers are depicted in Fig. 1 of the previously -mentioned US 9488235 patent, and in Fig. 1 of U.S. Patent Application Publication 2022 / 0362594, both of which are incorporated by reference in their entirety herein.) In other embodiments, no such shock absorber will be present. It will be understood that a fall-protection apparatus that is “non-motorized” as defined and described earlier herein, may still include such items as one or more electrically -powered sensors, monitors, communication units, actuators, and the like. Although discussions previously herein have primarily concerned products that completely arrest (stop) the motion of a human user, it is stipulated that in some embodiments, a fallprotection apparatus as described herein may serve merely to slow the fall of a user, and / or to allow the user to descend at a controlled rate.

[0141] It will be apparent to those skilled in the art that the specific exemplary elements, structures, features, details, configurations, etc., that are disclosed herein can be modified and / or combined in numerous embodiments. All such variations and combinations are contemplated by the inventor as being within the bounds of the conceived invention, not merely those representative designs that were chosen to serve as exemplary illustrations. Thus, the scope of the present invention should not be limited to the specific illustrative structures described herein, but rather extends at least to the structures described by the language of the claims, and the equivalents of those structures. Any of the elements that are positively recited in this specification as alternatives may be explicitly included in the claims or excluded from the claims, in any combination as desired. Any of the elements or combinations of elements that are recited in this specification in open-ended language (e.g., comprise and derivatives thereof), are considered to additionally be recited in closed-ended language (e.g., consist and derivatives thereof) and in partially closed-ended language (e.g., consist essentially, and derivatives thereof). Although various theories and possible mechanisms may have been discussed herein, in no event will such discussions serve to limit the claimable subject matter. To the extent that there is any conflict or discrepancy between this specification as written and the disclosure in any document that is incorporated by reference herein but to which no priority is claimed, this specification as written will control.

Claims

1. What is claimed is:

1. A fall-protection apparatus comprising: a drum with a safety line connected thereto and that is rotatable relative to a housing of the apparatus; and, a rotationally -activated braking device that comprises: at least one velocity -actuated pawl that is pivotably mounted on a pawl-support plate that is axially co-mounted with the drum, is co-rotatable with the dmm, and is in fixed rotational relation with the drum, the at least one pawl being pivotably movable between at least a disengaged position and an engaged position, the at least one pawl being biased toward the disengaged position, an inertia disk that is axially co-mounted with the pawl-support plate and that is rotatable relative to the pawl-support plate, through a predetermined range between at least a home position and an activated position; and, a ratchet with at least one tooth that is engagable by an engaging end of the at least one pawl when the at least one pawl is in the engaged position, wherein when the inertia disk is in the home position, rotation of the rotatable drum above a predetermined first threshold value of rotational velocity causes the at least one pawl to pivotably move into the engaged position, and, wherein when the inertia disk is in the activated position, rotation of the rotatable drum above a predetermined second threshold value of rotational velocity causes the at least one pawl to pivotably move into the engaged position, the predetermined second threshold value of rotational velocity being lower than the predetermined first threshold value of rotational velocity, wherein the inertia disk is biased toward the home position and is rotatable relative to the drum from the home position to the activated position upon the pawl-support plate experiencing a rotational acceleration that is above a predetermined threshold value of rotational acceleration; and, wherein the at least one pawl is configured to be a high-moment-of-inertia pawl that exhibits a moment of inertia of at least 130 g-cm2.

2. The fall-protection apparatus of claim 1 wherein the at least one velocity-actuated, high-moment- of-inertia pawl comprises an integral ballast element that extends axially from a major plane of a main body of the pawl so that the integral ballast element is axially displaced from the major plane of the main body of the pawl, with the integral ballast element providing from 25 % to 45 % of the total mass of the pawl.

3. The fall-protection apparatus of claim 2 wherein each of the at least one pawls comprises a main body with a leading portion that comprises the engaging end of the pawl and wherein the integral ballast element extends axially from the leading portion of the main body of the pawl.

4. The fall-protection apparatus of claim 3 wherein the main body of the pawl comprises a trailing portion, the pawl being configured so that when the pawl pivotably moves into the engaged position, the leading portion of the pawl moves generally radially outward and the trailing portion of the pawl moves generally radially inward.

5. The fall-protection apparatus of claim 3 wherein the pawl-support plate comprises an axially -open- ended cavity within which cavity at least a part of the integral ballast element of the pawl resides, the cavity being shaped and sized to allow the integral ballast element of the pawl to move generally radially outward as the pawl pivotably moves into the engaged position.

6. The fall-protection apparatus of claim 5 wherein the axially -open-ended cavity of the pawl-support plate comprises a first pawl-contacting surface that a first contact surface of the pawl contacts when the pawl is in the disengaged position.

7. The fall-protection apparatus of claim 1 wherein the pawl-support plate comprises an integral, axially -protmding buttress that comprises a second pawl-contacting surface that a second contact surface of the pawl contacts when the pawl is in the engaged position.

8. The fall-protection apparatus of claim 7 wherein the integral, axially -protruding buttress of the pawl-support plate comprises a third pawl-contacting surface that a third contact surface of the pawl contacts when the pawl is in the engaged position, the third contact surface of the pawl being a loadtransmitting surface that faces generally in a trailing direction and the third pawl-contacting surface of the buttress being a load-bearing surface that faces generally in a leading direction.

9. A fall-protection apparatus comprising: a drum with a safety line connected thereto and that is rotatable relative to a housing of the apparatus; and, a rotationally -activated braking device that comprises: at least one velocity -actuated pawl that is pivotably mounted on a pawl-support plate that is axially co-mounted with the drum, is co-rotatable with the dmm, and is in fixed rotational relation with the drum, the at least one pawl being pivotably movable between at least a disengaged position and an engaged position and being biased toward the disengaged position,an inertia disk that is axially co-mounted with the pawl-support plate and that is rotatable relative to the pawl-support plate, through a predetermined range between at least a home position and an activated position; and, a ratchet with at least one tooth that is engagable by an engaging end of the at least one pawl when the at least one pawl is in the engaged position, wherein when the inertia disk is in the home position, rotation of the rotatable drum above a predetermined first threshold value of rotational velocity causes the at least one pawl to pivotably move into the engaged position, and, wherein when the inertia disk is in the activated position, rotation of the rotatable drum above a predetermined second threshold value of rotational velocity causes the at least one pawl to pivotably move into the engaged position, the predetermined second threshold value of rotational velocity being lower than the predetermined first threshold value of rotational velocity, wherein the inertia disk is biased toward the home position and is rotatable relative to the drum from the home position to the activated position, upon the pawl-support plate experiencing a rotational acceleration that is above a predetermined threshold value of rotational acceleration; and, wherein each of the at least one pawls comprises a ferromagnetic material with the pawl being biased toward the disengaged position by way of a biasing magnet that is mounted in the inertia disk; and, wherein the inertia disk is biased toward the home position by the same biasing magnet that is mounted in the inertia disk and that biases the pawl toward the disengaged position.

10. The fall-protection apparatus of claim 9 wherein each of the at least one pawls comprises a main body with a leading portion and a trailing portion and comprises an integral ballast element that extends axially from the leading portion of the main body of the pawl so that the integral ballast element is axially displaced from a major plane of the main body of the pawl, with the integral ballast element and the leading portion of the main body of the pawl collectively providing a leading section of the pawl and with the integral ballast element providing from 25 to 45 % of the total mass of the pawl.

11. The fall-protection apparatus of claim 10 wherein the biasing magnet is radially -oriented and wherein when the at least one pawl is in the disengaged position and the inertia disk is in the home position, a center of mass of the leading section of the pawl is positioned generally radially outward of, and closely abutting, the biasing magnet; wherein when the inertia disk moves from the home position toward the activated position the biasing magnet moves away from the leading section of the pawl along a generally circumferential path, toward the trailing portion of the pawl; and, wherein when the pawl moves from thedisengaged position toward the engaged position, the leading section of the pawl moves generally radially outward away from the generally circumferential path followed by the biasing magnet.

12. The fall-protection apparatus of claim 11 wherein when the inertia disk moves from the home position to the activated position, the biasing magnet of the inertia disk moves through an angular arc of from 10 degrees to 20 degrees, from the location in which the center of mass of the leading section of the pawl is positioned generally radially outward of, and closely abutting, the biasing magnet, to a location in which a pivot axis of the pawl is positioned generally radially outward of the biasing magnet, so that the biasing magnet exhibits a displacement ratio of from 1.2 to 2.0.

13. The fall-protection apparatus of claim 10 wherein the main body of the at least one pawl is coplanar with the inertia disk and wherein the inertia disk comprises at least one notch that is radially- outwardly -open-ended and wherein when the at least one pawl is in the disengaged position, the main body of the pawl resides entirely within the at least one notch of the inertia disk and entirely within an imaginary circle defined by one or more radially -outwardmo st surfaces of the inertia disk.

14. The fall-protection apparatus of claim 13 wherein the pawl-support plate comprises an integral, axially-protruding buttress that comprises a first inertia-disk-contacting surface that faces generally in a trailing direction and a second inertia-disk-contacting surface that faces generally in a leading direction.

15. The fall-protection apparatus of claim 14 wherein the at least one radially-outwardly-open-ended notch of the inertia disk comprises a leading end and a trailing end; wherein the inertia disk comprises a first contact surface that is located generally toward the trailing end of the notch and that faces generally in a leading direction, the first contact surface of the inertia disk being in contact with the first inertia-diskcontacting surface of the buttress of the pawl support plate when the inertia disk is in the home position; wherein the inertia disk comprises a generally -radially -outwardly -protruding shoulder that is located within the radially -outwardly -open-ended notch of the inertia disk between the first contact surface of the inertia disk and the leading end of the notch; and, wherein the shoulder of the inertia disk comprises a second contact surface of the inertia disk, the second contact surface of the inertia disk facing generally in a trailing direction and being in contact with the second inertia-disk-contacting surface of the buttress of the pawl support plate when the inertia disk is in the activated position.

16. The fall-protection apparatus of claim 15 wherein the first and second contact surfaces of the inertia disk, and the first and second inertia-disk-contacting surfaces of the buttress of the pawl support plate, are configured so that in rotatably moving from the home position to the activated position, the inertia disk rotates through an arc of partial rotation of from 5 degrees to 25 degrees.

17. The fall-protection apparatus of claim 15 wherein the pawl-support plate comprises an axially- open-ended cavity within which cavity at least a part of the integral ballast element of the pawl resides, the axially -open-ended cavity of the pawl-support plate comprising a first pawl-contacting surface that a first contact surface of the integral ballast element of the pawl contacts when the pawl is in the disengaged position, and the cavity being shaped and sized to allow the integral ballast element of the pawl to move generally radially outward as the pawl pivotably moves into the engaged position.

18. The fall-protection apparatus of claim 9 wherein the inertia disk is made of a non-ferromagnetic material chosen from the group consisting of non-ferromagnetic metals, alloys, and blends; and, organic polymeric materials.

19. The fall-protection apparatus of claim 9 wherein the fall-protection apparatus is configured so that when the inertia disk is in the activated position and the pawl is in the engaged position and in the absence of any substantial unwinding force applied to the safety line, a magnetic force between the biasing magnet of the inertia disk and the pawl is sufficient to cause the pawl to return to the disengaged position and to cause the inertia disk to return to the home position, so that the braking device of the fall-protection apparatus comprises a self-unlocking configuration.

20. The fall-protection apparatus of claim 9 wherein the apparatus is a self-retracting lifeline in which the safety line comprises a proximal end that is connected to the rotatable drum and a distal end comprising a gated connector that is attachable to a harness of a human user of the apparatus or to an anchorage of a workplace, with the self-retracting lifeline comprising a motor spring that biases the rotatable dmm toward rotating in a winding direction that retracts the safety line into a housing of the self-retracting lifeline and winds the safety line onto the drum; and, wherein when the inertia disk is in the activated position and the pawl is in the engaged position and in the absence of any substantial unwinding force applied to the safety line, a magnetic force between the biasing magnet of the inertia disk and the pawl is insufficient to cause the pawl to leave the disengaged position and to cause the inertia disk to leave the activated position, with the apparatus being configured so that in the absence of any substantial unwinding force applied to the safety line, the motor spring causes the drum and the pawl-support plate to rotate in the winding direction so that the at least one pawl moves circumferentially in the trailing direction so that a secondary contact surface of a leading section of the pawl impinges on a secondary contact surface of a tooth of the ratchet thus urging the leading section of the pawl radially inward, after which the magnetic force between the biasing magnet of the inertia disk and the pawl is sufficient to cause the pawl to return to the disengaged position and to cause the inertia disk to return to the home position, so that the braking device of the fall-protection apparatus comprises a motor-spring- assisted unlocking configuration.

21. The fall-protection apparatus of claim 9 wherein the at least one pawl is configured to be a high- moment-of-inertia pawl that exhibits a moment of inertia of at least 130 g-cm2.

22. A fall-protection apparatus comprising: a drum with a safety line connected thereto and that is rotatable relative to a housing of the apparatus; and, a rotationally -activated braking device that comprises: at least one velocity -actuated pawl that is pivotably mounted on a pawl-support plate that is axially co-mounted with the drum, is co-rotatable with the dmm, and is in fixed rotational relation with the drum, the at least one pawl being pivotably movable between at least a disengaged position and an engaged position and being biased toward the disengaged position, an inertia disk that is axially co-mounted with the pawl-support plate and that is rotatable relative to the pawl-support plate in a trailing direction and in a leading direction, through a predetermined range between at least a home position and an activated position; and, a ratchet with at least one tooth that is engagable by an engaging end of the at least one pawl when the at least one pawl is in the engaged position, wherein when the inertia disk is in the home position, rotation of the rotatable drum above a predetermined first threshold value of rotational velocity causes the at least one pawl to pivotably move into the engaged position, and, wherein when the inertia disk is in the activated position, rotation of the rotatable drum above a predetermined second threshold value of rotational velocity causes the at least one pawl to pivotably move into the engaged position, the predetermined second threshold value of rotational velocity being lower than the predetermined first threshold value of rotational velocity, wherein the inertia disk is biased in the leading direction toward the home position and is rotatable in the trailing direction relative to the pawl-support plate from the home position to the activated position, upon the inertia disk experiencing a rotational acceleration that is above a predetermined threshold value of rotational acceleration; and, wherein the inertia disk is actively damped by an active damping mechanism that retards both trailing-direction rotation of the inertia disk and leading-direction rotation motion of the inertia disk.

23. The fall-protection apparatus of claim 22 wherein the active damping mechanism comprises at least one damping magnet that is mounted on the inertia disk; wherein the inertia disk is comprised of a material that is not ferromagnetic and the pawl-support plate is comprised of an electrically conductive material that is not ferromagnetic; and, wherein the at least one damping magnet is positioned on the inertia disk, in an axially-oriented configuration, so that rotation of the inertia disk in the leading direction or the trailingdirection relative to the pawl-support plate causes the damping magnet to induce eddy currents in the pawlsupport plate thus retarding the rotation of the inertia disk in the leading direction or the trailing direction relative to the pawl-support plate.

24. The fall-protection apparatus of claim 22 wherein when the inertia disk is not rotating relative to the pawl-support plate, the at least one damping magnet does not induce any eddy currents in the pawlsupport plate and the inertia disk is not subjected to any damping force by the damping magnet.

25. The fall-protection apparatus of claim 22 wherein the inertia disk is biased in the leading direction toward the home position by way of at least one biasing magnet that is mounted in the inertia disk, the at least one biasing magnet of the inertia disk being a separate magnet from the damping magnet of the inertia disk, and the at least one biasing magnet being radially oriented and being spaced apart from the damping magnet.

26. The fall-protection apparatus of claim 25 wherein each of the at least one pawls comprises a ferromagnetic material with the pawl being biased toward the disengaged position by the same at least one biasing magnet that biases the inertia disk in the leading direction toward the home position.

27. The fall-protection apparatus of claim 22 wherein the pawl-support plate comprises an integral, axially-protruding buttress that comprises a first inertia-disk-contacting surface that faces generally in a trailing direction and a second inertia-disk-contacting surface that faces generally in a leading direction, with a first contact surface of the inertia disk being in contact with the first inertia-disk-contacting surface of the buttress of the pawl support plate when the inertia disk is in the home position and with a second contact surface of the inertia disk being in contact with the second inertia-disk-contacting surface of the buttress of the pawl support plate when the inertia disk is in the activated position, and wherein the pawlsupport plate and the integral, axially -protruding buttress of the pawl-support plate, are integral with the drum to which the safety line is connected.

28. The fall-protection apparatus of claim 22 wherein the ratchet is configured so that it cannot rotate relative to a housing of the apparatus, and wherein the apparatus is configured so that upon the engaging of the engaging end of the at least one pawl with the at least one tooth of the ratchet, the pawl-support plate and the dmm are both brought to a hard stop, and wherein the safety line that is attached to the drum includes an in-line shock-absorber.

29. The fall-protection apparatus of claim 22 wherein the ratchet is configured so that it cannot rotate relative to a housing of the apparatus, wherein the braking device comprises a friction brake comprising at least one layer of friction material, and wherein the apparatus is configured so that upon the engaging ofthe engaging end of the at least one pawl with the at least one tooth of the ratchet, the drum and pawlsupport plate continue to rotate relative to the ratchet until brought to a halt by the friction brake.

30. The fall-protection apparatus of claim 22 wherein the ratchet is configured so that it can rotate relative to a housing of the apparatus, wherein the braking device comprises a friction brake comprising at least one layer of friction material, and wherein the apparatus is configured so that upon the engaging of the engaging end of the at least one pawl with the at least one tooth of the ratchet, the ratchet begins to rotate relative to the housing of the apparatus and continues to rotate, along with the drum and the pawlsupport plate, until the rotation of the ratchet, drum and pawl-support plate are brought to a halt by the friction brake.

31. The fall-protection apparatus of claim 22 wherein the apparatus is a self-retracting lifeline in which the safety line comprises a proximal end that is connected to the rotatable drum and a distal end comprising a gated connector that is attachable to a harness of a human user of the apparatus and / or to an anchorage of a workplace, with the self-retracting lifeline comprising a motor spring that biases the rotatable dmm toward rotating in a winding direction that retracts the safety line into a housing of the self-retracting lifeline and winds the safety line onto the drum.

32. The fall-protection apparatus of claim 31 wherein the self-retracting lifeline comprises a housing within which a shaft is rotatably mounted, with the drum and the pawl-support plate being fixed to the shaft so as to rotate with the shaft.

33. The fall-protection apparatus of claim 31 wherein the self-retracting lifeline comprises a housing within which a shaft is non-rotatably mounted, with the drum and the pawl-support plate being mounted on the shaft so as to be able to rotate relative to the shaft.

34. The fall-protection apparatus of claim 22 wherein the at least one pawl is configured to be a high- moment-of-inertia pawl that exhibits a moment of inertia of at least 130 g-cm2.

35. The fall-protection apparatus of claim 34 wherein each of the at least one pawls is configured to be a high-moment-of-inertia pawl that exhibits a moment of inertia of at least 130 g-cm2;, and wherein each of the at least one pawls comprises a ferromagnetic material with the pawl being biased toward the disengaged position by way of a biasing magnet that is mounted in the inertia disk; and, wherein the inertia disk is biased toward the home position by the same biasing magnet that is mounted in the inertia disk and that biases the pawl toward the disengaged position.

Images