Inter-element latch activation

Abstract

A self-retracting lifeline (SRL) device using a system, method of use and system for controlling dynamic response between members that causes cessation of relative motion between the members, where magnetic interaction, eddy current drag, centrifugal force and / or inertial force may provide various mechanisms for controlling motion. [Solution] A system is provided in which at least two members are in a kinematic relationship, the system comprising means for coupling a first member to at least one other member, thereby producing synchronized relative motion between the members, the coupling occurring in response to a prescribed system dynamic response, the dynamic response being selected from at least one of: (a) a specific velocity behavior of one or more of the members; (b) a specific acceleration behavior of one or more of the members; and (c) a specific jerk behavior of one or more of the members.

Description

[Technical field]

[0001] Described herein is a system for controlling the relative velocity between members, a method of use, and a self-retracting lifeline (SRL) device employing the system. [Background technology]

[0002] Applicant's co-pending and granted patents in the field of eddy current related devices include U.S. Pat. No. 8,851,235, U.S. Pat. No. 8,490,751, NZ Patent No. 619034, NZ Patent No. 627617, NZ Patent No. 627619, NZ Patent No. 627633, NZ Patent No. 627630, and other equivalents, all of which are incorporated herein by reference. In particular, NZ Patent No. 627617 describes a method of achieving a latching action between elements, the contents of which are incorporated herein by reference. While the device described in NZ Patent No. 627617 may be useful, other methods of controlling relative motion and / or damping may also be achieved, or at least provide the public with options.

[0003] Further aspects and advantages of the system, method of use and self-retracting lifeline (SRL) device will become apparent from the following description, which is given by way of example only. Summary of the Invention

[0004] Described herein is a system, method of use and a self-retracting lifeline (SRL) device employing the system to control dynamic response between members that causes cessation of relative motion between the members. Magnetic interaction, eddy current drag, centrifugal forces and / or inertial forces may provide various mechanisms for controlling motion.

[0005] In a first aspect, there is provided a system having at least two members in a kinematic relationship, the system comprising means for coupling a first member to at least one other member, thereby causing synchronous relative motion between the members, the coupling occurring in response to a defined system dynamic response, the dynamic response being: (a) A particular speed movement of one or more of the members; (b) a specific acceleration movement of one or more of the members; (c) a specific jerk motion of one or more of the members; is selected from at least one of:

[0006] In a second aspect, there is provided a method of controlling relative motion between members, comprising the steps of: (a) selecting a system substantially as described herein; (b) applying a motive force to the system to cause motion of at least one member within the system; (c) inducing a connection between the members when a prescribed system dynamic response occurs; and A method is provided that includes:

[0007] In a third aspect, there is provided a self-retracting lifeline (SRL) incorporating a system substantially as described herein.

[0008] The described systems, methods of use and SRL devices offer the advantage of providing an alternative method for achieving motion control, or at least providing a choice to the public.

[0009] Further aspects of the system, method of use and SRL apparatus will become apparent from the following description, given by way of example only, and with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a simplified front view of an embodiment incorporating magnetic interaction between a braking element and a motion element. [Diagram 2]FIG. 13 is a simplified front view of another bi-stable embodiment. [Diagram 3] 4 is a graph showing magnetic force interactions for the bi-stable embodiment described above. [Figure 4] 13A and 13B are perspective and front views of another embodiment employing a cogging torque approach. [Diagram 5] 13A-13C are two graphs showing speed dependency results from the cogging torque approach. [Figure 6] FIG. 13 is a simplified front view of the barking element and cogging torque approach of the moving element. [Figure 7] FIG. 13 is a simplified front view of another embodiment utilizing a rotational degree of freedom. [Figure 8] FIG. 13 is a front view of another cam path embodiment. [Figure 9] FIG. 13 is a front view of another cam path embodiment. [Figure 10] FIG. 13 is a perspective view of another cam path embodiment. [Figure 11] FIG. 13 is a simplified perspective view of another cam path embodiment. [Figure 12] 11A-11C are simplified perspective and front views of another cam path embodiment. [Figure 13] FIG. 13 is a simplified front view of another cam path embodiment. [Figure 14] 11A-11C are various elevation views of another embodiment that uses a combination of cams, geometry, inertial response and eddy currents. [Figure 15] FIG. 1 is a simplified front view of a claw technology speed sensing device. [Figure 16] FIG. 1 is a simplified front view of a claw technology acceleration sensing device. [Figure 17] FIG. 2 is a simplified front view of the jerk sensing device. [Figure 18] 18A-18C are simplified front views of the jerk sensing device of FIG. 17 in various alignments. [Figure 19] FIG. 19 is a simplified front view of the magnetic interactions from the embodiment of FIGS. 17 and 18. [Figure 20]FIG. 13 is a simplified front view of another jerk sensing device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] As noted above, described herein are systems, methods of use and self-retracting lifeline (SRL) devices employing the systems to control dynamic response between members that causes cessation of relative motion between the members. Magnetic interaction, eddy current drag, centrifugal forces and / or inertial forces may provide various mechanisms for controlling motion.

[0012] For purposes of this specification, the terms "about" or "approximately" and grammatical variations thereof mean a quantity, level, degree, value, number, frequency, proportion, dimension, size, amount, weight, or length that differs by 30, 25, 20, 15, 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1% from a reference quantity, level, degree, value, number, frequency, proportion, dimension, size, amount, weight, or length.

[0013] The term "substantially" or grammatical variations thereof refers to at least about 50%, for example, 75%, 85%, 95%, or 98%.

[0014] The term "comprise" and grammatical variations thereof are to be construed as having their inclusive meaning, i.e., to mean including not only the directly referenced recited components but also other unspecified components or elements.

[0015] The term "jerk" or grammatical variations thereof refers to a change in acceleration, typically an abrupt change in acceleration as compared to normal operating parameters.

[0016] In a first aspect, there is provided a system having at least two members in a kinematic relationship, the system comprising means for coupling a first member to at least one other member, thereby causing synchronous relative motion between the members, the coupling occurring in response to a defined system dynamic response, the dynamic response being: (a) A particular speed movement of one or more of the members; (b) a specific acceleration movement of one or more of the members; (c) a specific jerk motion of one or more of the members; is selected from at least one of:

[0017] The inventors have actually created a system that involves coupling of members based on system dynamic response, the purpose of which is to have the members move in a synchronized manner under given conditions.

[0018] The connections between the components are (a) Mechanically, (b) Magnetically, (c) A combination of mechanical and magnetic This can be achieved.

[0019] Coupling may occur passively, and once coupled, the members may remain coupled or may be releasably coupled, or alternatively, coupling may be achieved by active means.

[0020] The synchronized motion can be an absolute zero velocity or stopping effect, which can be useful, for example, in a fall safety system where all motion needs to be stopped.

[0021] Coupling may also be based on, or at least influenced by, eddy current induced resistance, which, in the inventors' experience, is not required but can be useful to further tune the dynamic response characteristics.

[0022] In one particular embodiment, coupling between the members can be achieved by a mechanical coupling between at least one pawl coupled to a first member, the pawl performing an oscillatory motion operation, and at least one latch member on or at least one other member, the coupling occurring at a speed threshold responsive to a defined system dynamic response.

[0023] There may be a biasing relationship between the pawl and the latch member, the biasing relationship being achieved by use of at least one magnet arranged for attraction, repulsion, or alternating attractive and repulsive forces of the pawl.

[0024] At least one magnetic element may be disposed on both the pawl and the first member, such that rotation of the pawl and the first member changes the biasing relationship, thus creating oscillatory motion of the pawl. The pawl may be axially mounted on the first member, such that the center of gravity of the pawl is offset from the axis of rotation of the pawl to further affect the oscillatory effect.

[0025] As can be appreciated, the degree of vibration of the pawl can be varied depending on, for example, the speed of relative movement of the first member and the pawl (or the first member and at least one other member).

[0026] The dynamic response of the pawl can be further tuned by varying the inertia of the pawl. As mentioned above, the center of mass of the pawl can be offset from the axis of rotation of the pawl, assuming the pawl is connected to the first member in this manner. One or more portions of the pawl can be weighted to match the inertia of the pawl to the motion, thereby tuning the system dynamic response.

[0027] The system can operate as follows: (a) at a given speed, engagement occurs when the pawl moves to the deployed position for a time sufficient for the pawl to engage the latch member; (b) At speeds below a certain speed, the claws may not bind.

[0028] Binding can be avoided by having the pawl skip the latch member, i.e., the pawl does not deploy far enough to interfere with the latch member. The skipping can continue until the inertial effects of the pawl are overcome and the pawl deploys far enough to bind with the latch member.

[0029] The system is (a) If the speed of movement is insufficient to overcome the inertial effect of the claws, the claws may remain bound; (b) If the speed of movement is sufficient to overcome the inertial effects of the claw, uncoupling can occur. It can further operate in this way.

[0030] The degree of bias that induces the vibrations can be configured to provide a desired dynamic response behavior of the pawl.

[0031] In another particular embodiment, the coupling between the members may be achieved by a mechanical cam system based on the reaction effect of inertial forces and / or applied drag forces in response to a prescribed system dynamic response.

[0032] In the above system, the first member and at least one other member can be aligned and a cam mechanism can be disposed between the first member and the at least one other member. In practice, the system has at least two independently moving members.

[0033] At least one other member may be configured with either or both of inertial properties and / or deceleration resistance due to motion such that the at least one other member undergoes a slower motion relative to the first member when a motive force is applied to the system.

[0034] The relative velocity between the first member and at least one other member can result in a displacement between the members and can cause the members to separate via a prescribed path of motion of the cam profile, where separation refers to the members moving apart relative to one another.

[0035] Movement of the at least one other member can cause engagement with a latch member on or about the first member to couple at least one fastener on the at least one other member to the latch member.

[0036] As can be appreciated, coupling another member to the latch member also creates an indirect coupling between the first member and the other member.

[0037] The bond is (a) Geometric interface for latches; (b) the attractive force of magnetic poles, or (c) Combination of geometric interfaces and magnetic pole attraction for latching This can be achieved by:

[0038] In another particular embodiment, the coupling can rely on magnetic forces between the members configured to achieve an attractive force between the members that is sufficient to slow and stop relative motion between the members, such that the relative motion is synchronized according to a prescribed system dynamic response.

[0039] The magnetic force may be provided by magnetic pole elements acting between the members. For the purposes of this specification, the magnetic pole action is referred to as "cogging". The cogging system may be designed to achieve a stopping and holding action under the conditions the system is intended for, taking into account the dynamic behavior of the connected system and any surrounding energy absorbing means. The magnetic pole elements may be configured to be disabled or inactive under predetermined conditions. A change in magnetic pole action may be achieved, for example, by changing the separation distance between the members or portions thereof that include one or more magnets, thereby reducing the magnetic interaction forces.

[0040] The above systems may be continuously coupled systems in which an externally applied motive force results in an initial motion of the members, but if the motive force is sufficient to induce a prescribed system dynamic response, a slowing or stopping action takes effect immediately between the members.

[0041] As can be understood, in the first aspect above and in the specific embodiments described, the members may move in a substantially linear kinematic relationship. Alternatively, the members may move in a substantially rotational kinematic relationship. Both movements may be possible and appropriate depending on the device in which the system may be used. The examples given or used herein are described in a rotational embodiment. Equivalent linear embodiments will be apparent to those skilled in the art.

[0042] In yet another particular embodiment, the members may be in a substantially rotational kinematic relationship and coupling between the members may be achieved by a centrifugal designed system such that upon application of a motive force of a predetermined magnitude, the members couple in response to a prescribed system dynamic response.

[0043] The centrifugal force acting on the member may be influenced by the use of at least one weighting or weighted element or part thereof.

[0044] The first member and the at least one other member can be aligned, and one or more centrifugal mechanisms can be disposed between the first member and the at least one other member.

[0045] The velocity of the members can induce a displacement of the centrifugal mechanism, which in turn can cause the members to separate due to centrifugal force applied to at least one other member.

[0046] Movement of the at least one other member can cause coupling with the latch member on or about the first member, coupling at least one fastener of the at least one other member to the latch member. As can be appreciated, coupling of the other member to the latch member also creates an indirect coupling between the first member and the other member.

[0047] The bond is (a) Geometric interface for latches; (b) the attractive force of magnetic poles, or (c) Combination of geometric interfaces and magnetic pole attraction for latching This can be achieved by:

[0048] As mentioned above, the dynamic response can be one of three ways. More specifically, specific examples of how the three actions are performed can be as follows: The speed sensing device may be configured using a pawl actuated by a centripetal force acting against the constraint of a biasing element; An acceleration sensing device can exploit the inertial behavior of the pawl to rotate the pawl about its pivot axis in response to acceleration of the pawl mounting plate; A jerk sensing device may be constructed taking advantage of the non-linear shear resistance force that exists between a pair of magnetic poles.

[0049] As will be appreciated, configurations may be varied and the above options should only be viewed as non-limiting examples.

[0050] In a second aspect, there is provided a method of controlling relative motion between members, comprising the steps of: (a) selecting a system substantially as described herein; (b) applying a motive force to the system to cause motion of at least one member within the system; (c) inducing a connection between the members when a prescribed system dynamic response occurs; and A method is provided that includes:

[0051] In a third aspect, there is provided a self-retracting lifeline (SRL) incorporating a system substantially as described herein.

[0052] As noted above, the described device may be used in an SRL device, for which the ability to detect and activate braking elements is important.

[0053] Detection of a fall event is typically triggered by a mechanism that responds to a change in the state of the line. The mechanism could potentially be triggered by the line's displacement, velocity, acceleration or jerk (rate of change of acceleration), or by a combination of these signals.

[0054] Existing SRLs generally use a speed or acceleration mechanism, using a ratchet and pawl arrangement to couple the spool to the brake. Either the ratchet plate or the pawl set can be attached to the rotating spool.

[0055] The linear configuration may include a means to sense changes in acceleration (jerk) of a carrier (moving element). The carrier may be attached to a lidar (braking element) of known mass with a given inertia. When a contact force is applied to the carrier, the lidar and carrier remain coupled and aligned. Changes in the applied force on the carrier (jerk) cause the lidar to slide relative to the carrier due to inertial effects. The inertial effects can then be tracked by the displacement between the lidar and carrier. As the acceleration of the carrier changes, the relative displacement between the lidar and carrier also changes.

[0056] The same principle may be used in the rotational direction: the lidar is free to rotate with the carrier, and changes in angular acceleration applied to the carrier can result in a relative angular displacement between the carrier and the lidar.

[0057] In addition to SRL applications, the apparatus and methods can be used in a variety of other applications, including, by way of non-limiting example, speed or load control of: Auto-belay device; Rotary turbine rotors; Exercise equipment, e.g. rowing machines, epicyclic trainers, weight training equipment; roller coasters and other amusement rides; Elevator and escalator systems; Evacuation descent and fire escape devices; Conveyor systems; Rotary drives in factory production facilities; material handling equipment such as conveyor belts and braking devices in chutes; Roadside safety systems, for example energy absorbers, may be connected to a system that provides crash damping through dissipation of energy via the energy absorber; Vehicle seat belts; Zip lines; Braking mechanism for trolleys and carriages; bump stops in transportation applications; Bump stops in crane applications; torque or force limiting devices in mechanical drivetrains; Structural overload protection of wind turbines; Load limitations and energy dissipation in structures, buildings and bridges.

[0058] The above-described systems, methods of use, and SRL devices offer the advantage of providing alternative ways of achieving motion control without relying solely on centrifugal and / or eddy current forces, for example. In addition, the relationship between the parts and the speed at which motion control occurs may be influenced using the embodiments described herein.

[0059] The above embodiments may also be generally described as consisting of the parts, elements, and features referenced or shown in the specification of this application, either individually or collectively, and any or all combinations of two or more of said parts, elements, or features, where particular wholes are described herein as being known equivalents in the art to which the embodiments pertain, and such known equivalents are deemed to be incorporated herein as if individually set forth.

[0060] Where specific wholes are described herein as being known equivalents in the art to which the invention pertains, such known equivalents are deemed to be incorporated herein as if individually set forth.

[0061] Examples of the above systems, methods of use and self-retracting lifeline (SRL) devices employing these devices will now be described with reference to specific examples.

[0062] Example 1 Below is a typical example of magnetic latching caused by the movement of a braking element.

[0063] Figure 1 shows an example of magnetic latching caused by pawl motion. The direct attractive force exerted by the permanent magnet 10 can be used to augment or reverse eddy current drag (if eddy current forces are used) as a means of actuating the pawl 11 between a spool 12 (a first member) and a concentric outer element 13 (another member). When the pawl 11 is latched to the concentric outer element 13, the motion between the spool 12 and the concentric outer element 13 is synchronized.

[0064] Example 2 A bi-stable device may be used in conjunction with the tube and cylinder (plunger) approach described in the applicant's co-pending New Zealand Patent Application No. 619034. In this example, an eddy current brake arrangement on the plunger 50 is shown as a means of retarding the initial relative motion between the active brake element / plunger 50 and the lead screw 51 and / or as a means of latching and locking the brake 50 at the end of the plunger's axial travel stroke 52,53 as shown in Figure 2. The output for the force / motion interaction is shown graphically in Figure 3 showing how the forces at either end of the plunger stroke 52,53 are high and then drop off through the travel phase of the plunger stroke 52,53, note that the term "force" refers to the force required to translate the plunger laterally and the motion is the lateral motion of the plunger.

[0065] Example 3 In a further embodiment, an example of cogging is shown in Figure 4. Cogging torque results from magnetic poles rotating relative to one another, generally indicated by arrows 60. This results in a speed dependent torque relationship best seen in the graph shown in Figure 5, where F represents the force / degree of vibration and o represents a motion path that can allow for slow lock-off of brakes that rely on eddy current damping (maximum latching force occurs at slow speeds).

[0066] 6 shows how magnets 60 slowly align, thereby stopping further motion. This embodiment is capable of completely stopping relative motion between parts, but without partial interference or friction, i.e., the braking is frictionless.

[0067] Figure 6 also shows a centrifugal embodiment, where one of the members contains a weighted ball that moves along a defined path. At maximum rotational force, the ball moves and changes the center of gravity, thereby changing the system dynamic response.

[0068] Example 4 Magnetic latching of the braking element can also be arranged about a rotational degree of freedom perpendicular to the main drive axis, in this example the axis of rotation 70 of braking element 71 relative to the motion element 72 (rotor). Figure 7 shows three embodiments of this type of system. The embodiments of Figure 7 also show the use of biasing means (magnets and / or springs) to further tune the system dynamic response.

[0069] Example 5 The relative rotation between the moving and braking elements may be further influenced by the use of inertial or centrifugal forces to create a speed differential between the elements. In one embodiment, the speed differential may be used to drive the axial displacement by a cam path 100 as shown in Figures 8-13. Different profiles may be used to control the motion of the balls, thus altering the centrifugal forces acting on the parts and their motion characteristics.

[0070] The axial load required to maintain contact between the two halves in the embodiment shown in Figures 8-13 may be generated by a spring force, a magnetic repulsive force, or as a result of eddy current resisting torque acting due to the angle of the cam 100. Additional details regarding this force generation are shown in Figures 12 and 13.

[0071] Example 6 Another configuration utilizing a combination of cam profile, inertial response and eddy current drag-velocity relationships is shown in FIG.

[0072] Example 7 As mentioned above, the ability to detect and actuate braking elements is important to an SRL device.

[0073] Detection of a fall event is typically triggered by a mechanism that responds to a change in the state of the line. The mechanism could potentially be triggered by the line's displacement, velocity, acceleration or jerk (rate of change of acceleration), or by a combination of these signals.

[0074] Existing SRLs generally use a speed or acceleration mechanism, using a ratchet and pawl arrangement to couple the spool to the brake. Either the ratchet plate or the pawl set can be attached to the rotating spool.

[0075] As shown in FIG. 15, the velocity sensing device of the technology can be constructed using a pawl (braking element) 110 that is actuated by a centripetal force acting against the constraint of a biasing element (spring) 111 .

[0076] The velocity sensing device of the art can exploit the inertial behavior of the pawl 112 to rotate the pawl 112 about its pivot axis 113 in response to acceleration of the mounting plate of the pawl 112. This approach is illustrated in FIG.

[0077] Example 8 A jerk sensing device can be constructed by utilizing the nonlinear shear stress that exists between a pair of magnetic poles.

[0078] A linear configuration is shown in Figures 17-19. The configuration shows a means to sense changes in carrier acceleration (jerk). Carrier 120 is attached to a lidar 130 of known mass with a given inertia. When a contact force is applied to carrier 120, lidar 130 and carrier 120 remain coupled and aligned. A change in the force applied to carrier 120 (jerk) causes lidar 130 to slide relative to carrier 120 due to inertial effects. The inertial effects can then be tracked by the displacement d. As the acceleration of carrier 120 changes, the relative displacement between lidar 130 and carrier 120 changes.

[0079] It will be appreciated that aspects of the system, method of use, and self-retracting lifeline (SRL) device employing the system have been described by way of example only, and that modifications and additions may be made without departing from the scope of the claims herein.

Claims

1. A self-retracting lifeline, comprising: a coupler configured to selectively couple a spool with a line to a latch on an external element using magnetic interaction to reduce or stop relative motion between the spool and the line on the spool and the external element; the coupler includes a pawl that is coupled to the spool and rotates with the spool as line on the spool is unwound from the spool; the pawl and the external element face each other such that the magnetic interaction occurs between at least one magnet disposed on both the pawl and the external element; when line is unwound from the spool, causing the spool to rotate below a speed threshold, the pawls oscillate radially inward and outward relative to the axis of rotation of the spool due to a change in biasing relationship caused by the magnetic interaction, and the coupler does not couple the spool to the external element; A self-retracting lifeline wherein when line is unwound from the spool causing the spool to rotate above a speed threshold, the claws of the coupler move radially outwardly far enough to a deployed position where the claws or portions of the claws engage a latching geometric interface of the external element, thereby coupling the external element and the spool and stopping relative motion between the external element and the spool.

2. 2. The self-retracting lifeline of claim 1, wherein the pawl is directly connected to the spool.

3. The self-retracting lifeline of claim 1 , wherein the pawl is biased to an uncoupled position.

4. 4. The self-retracting lifeline of claim 3, wherein the bias is a spring.

5. 10. The self-retracting lifeline of claim 1, wherein the outer element latching geometric interface includes teeth.

6. 6. The self-retracting lifeline of claim 5, wherein the outer element includes at least two tines.

7. 2. The self-retracting lifeline of claim 1, wherein a distal end of said pawl engages a latching geometric interface.

8. 2. The self-retracting lifeline of claim 1, wherein the latching geometric interface of the outer element is formed as a ratchet such that once engaged, the spool can only move in the reverse direction to wind line onto the spool and cannot unwind line from the spool.

9. 2. The self-retracting lifeline of claim 1, wherein the external element is a housing around the spool or a portion of the spool.

10. 2. The self-retracting lifeline of claim 1, wherein said pawl has an axis of rotation, said axis of rotation of said pawl being offset from said axis of rotation of said spool.

11. 2. The self-retracting lifeline of claim 1, wherein the pawl is an elongated element having a first end connected to the spool and an opposite second end that latches with the external element upon coupling.

12. 2. The self-retracting lifeline of claim 1, wherein when relative motion between the external element and the spool stops, the absolute velocity of the spool and the line unwound from the spool becomes zero.

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