WO2024144946A2 - Electrically controllable device for preventing fatigue and acute injury - Google Patents

Abstract

An injury prevention device modulates a force experienced by a portion of a user's body through the use of an electrostatic clutch. The clutch can connect the portion of the body to another portion of the user's body or to an external structure, such as a seat or harness. A controller enables the electrostatic clutch to operate in several modes, selectively permitting free movement, restraint, energy dissipation, and load support. The device may include a tether and a tether housing to direct the force path between the user's body and an attachment point for the electrostatic clutch. The clutch may be provided in rotary, universal, and linear styles.

Description

TITLE

ELECTRIC ALLY-CONTROLLABLE DEVICE FOR PREVENTING FATIGUE AND ACUTE INIURY

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit under 35 U.S.C. § 119 of U.S. Provisional Application Serial No. 63/426,172, filed on November 17, 2022, and Application Serial No. 63/543,196, filed on October 9, 2023, each of which is incorporated herein by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

[0002] This invention was made with United States government support under W81XWH22P003 and HT942523C0024 awarded by the Defense Health Agency. The U.S. government has certain rights in the invention.

BACKGROUND OF THE INVENTION

[0003] The present disclosure relates safety devices used to prevent injuries due to high body accelerations, impacts, rapid environmental changes, and other similar injuries. More specifically, the disclosure relates to devices that slow the rate of acceleration of a body part or support the movement of a body part.

[0004] Many professions subject individuals to dangerous and physically high-stress working environments that frequently cause fatigue, chronic injuries and acute injuries. This leads to high worker turnover, injury downtime and early retirement. Examples of these include combat air pilots, athletes, drivers, paratroopers, first-responders, manual laborers, health care professionals, and ground-based military personnel.

[0005] Preventative hardware devices designed to prevent injuries exist, but have limitations that prevent effective use in many cases. Current solutions are often single use, restrict the motion of their user to a degree that prevents users from performing tasks, or require a greater structure for attachment such that free movement is not possible. Additionally, current protective devices typically provide only protective measures from one of supportive forces, energy dissipation, and motion restriction.

[0006] The simplest type of safety device is a restraint. Restraints are reusable and are applied to prevent acute injuries during discrete events such as high accelerations in vehicular crashes. Seat belts are the most broadly recognizable of these devices. Variations of restraints beyond seatbelts are used in motorsports and other applications. For example, devices to protect the head and neck of operators under high-G loads have been developed for motorsports crashes (up to and exceeding 70G). In motorsports, a head and neck support (HANS) device has been employed to prevent excess head rotation in a car crash. In the event of a front-end collision, dynamic loading from the head is transmitted to the tethers, to the collar, to the seat restraints rather than to the neck. Despite the benefits in the event of a catastrophic event, restraints can limit the movement of the user during normal use.

[0007] Single-use protection systems include airbags and inertial reel devices and can allow free movement during normal use and are designed to protect the user from acute injury in a single event. Airbags in cars dissipate kinetic energy to reduce injurious accelerations. Inertial reel devices such as those in ejection seats typically include an explosive charge or blade to release a spring which retracts tethers or restraints to upright and support a pilot during ejection. While overcoming the drawbacks of restraints, single-use protection systems can only be activated once and must be discarded and replaced.

[0008] The military has developed rate-activated tethers (RATs) which incorporate a shear thickening fluid in a strapping material. Under low joint velocities, the freedom of motion is maintained, but under high joint velocities, the RAT will provide large damping forces. These devices behave as dampers. One drawback of the RAT is activation of the stiffening behavior under quick voluntary movements of the operator.

[0009] For chronic fatigue and injury, reusable support systems are designed to offload the forces experienced by users in their muscles and joints. These systems are typically applied in environments where similar repetitive tasks are performed for long periods of time or in situations where a near-constant load is applied unceasingly. Examples of support systems include tethered counterbalancers typically mounted overhead on assembly lines. These systems support a portion of the weight of a tool so that the effort needed to operate it is greatly reduced. These devices are too heavy or too encumbering to be mounted on the body, meaning that they must be mounted in the surrounding environment, which greatly limits versatility.

[0010] Some body-mounted safety devices use rate activated tethers, pneumatic muscles, and air bladders to support repetitive or near-constant loads. A downside of these devices is that they resist voluntary motions, which is uncomfortable, causes fatigue, and compromises the ability of the user to perform their tasks.

[0011] Therefore, it would be advantageous to develop a safety device that is electrically controllable, light and compact enough to be mounted on the body, and that allows free unencumbered movement when desired before, during, or after a high-injury-risk event is greatly desirable. BRIEF SUMMARY

[0012] According to embodiments of the present disclosure is an electrically-controllable, body-worn electroadhesive device that reduces the risk of injury by strategically preventing biomechanical motion of the body or providing supportive forces. The device is capable of three functions performed in combination or isolation: providing supportive force, restraint, or energy dissipation. In one embodiment, one or more electroadhesive clutches along with mechanical components are attached to a convenient part of the body close to or remote from the location of applied assistance. Mechanical loads are transmitted to the location of assistance via a cable and compressive sleeve. These loads can halt or resist motion in dangerous conditions or supply supportive forces to reduce mechanical loads in the user’ s body. In another embodiment, the electroadhesive clutches are attached directly to anchor points (either on the body or on body-mounted equipment) spanning the targeted part of the body. In each case, the devices can in isolation or combination: stop or slow undesired movement of the body in one electrically controllable state, can allow relatively unrestricted and fast motion of the body in another electrically-controllable state, and provide supportive forces in another electrically- controllable state.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS [0013] Fig. 1 shows the basic structure of an electroadhesive device.

[0014] Fig. 2 is an exploded diagram of an electrostatic clutch used in one embodiment of the injury prevention device.

[0015] Fig. 3 depicts an injury prevention device mounted to the torso and routed to the head (for multiple assistance modes/degrees of freedom) and ankle.

[0016] Fig. 4 shows the injury prevention device.

[0017] Fig. 5 is an embodiment of the injury prevention device including attachment loops.

[0018] Fig. 6 is an injury prevention device attached to a helmet.

[0019] Fig. 7 shows various components of the injury prevention device.

[0020] Fig. 8 is an exploded view of an electrostatic clutch used in an embodiment of the injury prevention device.

[0021] Fig. 9 is an embodiment of the injury prevention device with multiple tethers.

[0022] Fig. 10 is a diagram of the injury prevention device that interacts with a body harness. [0023] Fig. 11 shows an injury prevention device that interacts with a structure near the user.

[0024] Fig. 12 is an embodiment of the injury prevention device mounted to a seat.

[0025] Fig. 13 is another embodiment of the injury prevention device with the conduit terminated on an intermediate external structure.

[0026] Fig. 14 depicts an embodiment with clutch parts mounted on the body and external structures.

[0027] Fig. 15 shows a tether with a mechanical stop to prevent retraction.

[0028] Fig. 16 is an embodiment worn on the body and selectively limits head movement.

[0029] Fig. 17 is a diagram of control logic used to determine the mode in which the clutch operates as determined by sensor input.

[0030] Fig. 18 shows the injury prevention device spanning a single joint.

DETAILED DESCRIPTION

[0031] This invention relates to an electrically controllable, body-worn electroadhesive device 100 specifically designed for injury prevention by strategically resisting or supporting biomechanical motion of the body. In one embodiment, the injury prevention device 100 comprises an electrostatic clutch 101 connected to a tether 120 and a controller 110 to actuate the clutch 100. The clutch 101 may be body -worn or connected to a structure 118 external to the user. The tether 120 is connected to the clutch 101 at a first end and a body part at a second end. The clutch 101 is electrically operated to control movement of the tether 120 and the body part to which it is connected. Parts of the body that are protected may include: the head and neck, shoulders, elbows, wrists, fingers, back, hips, knees, ankles, toes, and any articulated joints in the body. Injury can be prevented in several ways, such as by providing supportive forces, restraint, and energy dissipation.

[0032] The device 100 is a quasi-passive injury prevention device 100 that utilizes the electrostatic clutch 101 to seamlessly transition between device states (e.g. free movement vs. restrained) for the purposes of injury prevention. The device 100 is differentiated from existing systems as it applies lower initial penalties to the user by being lighter, more form fitting, and more comfortable than similarly capable systems while simultaneously having lower power consumption requirements than active or semi-active systems. The device 100 uses an electrostatic clutch 101 to transition between states that may include transparent, supportive, energy dissipative, or restraining. [0033] The electrostatic clutch 101 comprises electrodes 102 separated by a dielectric material 103. Fig. 1 shows the basic principle of electrostatic adhesion, where a voltage is applied across two electrodes 102. When voltage is applied across these electrodes 102, the electrodes 102 are attracted to one another. This attractive force results in a normal force that can be used to resist relative motion of the two or more electrodes 102 directly or via resulting frictional forces. The magnitude of the attractive force can be controlled by modulating the voltage applied to the clutch 101. The magnitude of resistive force the clutch 101 can provide can be controlled by adjusting the total area of the clutch components engaged or by controlling the magnitude of the voltage applied across these clutch members. Electroadhesive clutch members are generally disengaged in the power-off state, which provides an added degree of safety in environments in which the user must maintain mobility in the event of a malfunction. [0034] Electrostatic clutches are generally ten times more compact, ten times lighter, and one thousand times more efficient than traditional mechanisms, such as current-driven electromagnetic devices. In addition to these key benefits, electrostatic clutches generate negligible amounts of heat, have near silent activation, and produce no measurable electromagnetic interference.

[0035] Here, the term ‘clutch member’ may be used interchangeably with the term ‘electrode’ 102 and describes a component or group of components capable of acting as an electrode 102 and transmitting a mechanical load through an interface that is connected by electrostatic attraction. Some embodiments of a clutch member are an electrode 102, an electrode 102 with a carrier, and a rigid substrate coated with a conductive layer. Clutch members may include a dielectric material 103. Clutch members may be composed solely by electrodes 102 capable of transmitting mechanical loads themselves as is the case in embodiments in which metal plates are used as both electrodes 102 and structural components. In other embodiments, clutch members comprising both electrodes 102 and reinforcing structural components may be used. Each clutch member is associated with an input or output of the clutch 101. At least two clutch members are required for the electrostatic clutch 101 to function. For simplicity clutch members may be drawn as a single component. ‘Clutch interface’ refers to the overlapping area of the input and output electrodes 102 over which a force of adhesion is established in the engaged state and may also refer to the opposing surfaces of the clutch members that contact one another.

[0036] Fig. 2 depicts an example embodiment of a clutch 101. In this embodiment, there are two outer clutch members 102. These members 102 comprise a polymer carrier with an aluminized side facing the interior of the member 102. This aluminized side is coated with a dielectric layer 103 across its surface except in regions in which an electrical connection is established. The two outer clutch members 102 are adhered to an outer clutch member reinforcing structure using pressure sensitive adhesive. In this embodiment, the clutch 101 is ring shaped. This ring includes mechanical connections to a greater structure that have not been illustrated.

[0037] In the embodiment shown in Fig. 2, the mechanical connection is a circle of through holes used to bolt to a larger structure. Enclosed within the two outer clutch members 102 is the rotating portion of the clutch 101. This includes an inner clutch member reinforcing structure. This structure is a planar disk with a toothed pattern on its inner diameter for mechanically interfacing with a spline shaft. Adhered to this structure using a patterned pressure sensitive adhesive are two inner clutch members 102 of similar construction to the outer clutch members 102. Electrical connections are made to the outer clutch members 102 and voltage is applied. In this embodiment, the clutch 101 can be electrically modeled as two capacitors in series. The voltage applied across the outer electrodes 102 results in an intermediate voltage experienced at the inner electrodes 102. The voltage potential across the clutch interface results in adhesion.

[0038] Electrostatic clutches are most typically linear, rotary, or universal in behavior. Linear clutches resist linear motion by providing shear forces. The movement of a linear clutch 101 is typically constrained to a one- or two-dimensional moment in a plane or a locally approximate planar surface. Rotary clutches 101 allow rotary motion around an axis when they are disengaged. Universal clutches 101 provide significant shear and normal forces at the clutch interface to resist translation in plane with the clutch interface, normal to the clutch interface and also rotation about an axis normal to the clutch interface.

[0039] Fig. 3 shows the device 100 mounted to the body of a user. Fig. 4 shows further detail of an injury prevention device 100 having the tether 120 connected to a rotary-style clutch 101. In this example embodiment, the device 100 comprises an electrostatic clutch 101 that couples or decouples mechanical components in response to an electrical signal provided by a battery 130 or other source of electrical energy. The battery 130 or source of energy may or may not include a voltage driver 131. Mechanical components, such as the tether 120, interface with the body, clothing, or body -worn equipment. Further, a sensor 140 detects information about the environment and/or user intent and the controller 110 uses information from the sensor 140 to determine whether supportive forces should be provided or whether motion should be restricted or resisted. The controller 1110 may include a circuit that includes logic control components, voltage control components, a microprocessor, and/or a voltage transformer. Using the controller 110, the state of the electrostatic clutch 101 can change from engaged to disengaged as needed to enable these state changes. The degree of engagement can also be controlled by modulating the voltage applied to enable energy dissipation.

[0040] The device 100 may include one or multiple electrostatic clutches 101. The electrostatic clutch 101 can have several functions, including but not limited to: (1) limiting force applied to a load to prevent damage to the load; (2) limiting torque to protect components of a mechanical system; (3) limiting torque to an expected range to limit damage to items in the path of moving components or to limit damage to the moving components themselves; (4) limiting torque to prevent sudden increases in forces applied to a user or other load for safety reasons; and (5) altering the connections within a drive train to adjust speed and maximum force output.

[0041] In addition, the clutch 101 can couple and decouple body segments from each other to affect joint moments. The magnitude of the joint moment produced can be controlled by coupling and decoupling mechanical components such as springs or dampers and by coupling and decoupling body segments from one another.

[0042] The injury prevention device 100 can be configured in many ways with variations in attachments, the type of electrostatic clutch 101, and control behavior. Embodiments may include attachments to only the user’s body or may include attachments to a structure 118 external to the body. Embodiments may include electrostatic clutches 101 of rotary, linear or universal type in singles or multiples or in combination between types. Mechanical transitions may be routed or unrouted. In routed designs, the majority of the structure of the device 100 is remote to the location of applied assistance. In unrouted designs, the majority of the structure of the device 100 spans the assisted joint or is located proximal to the location of applied assistance. Control of the device 100 may include modes such as following, support, restraint, energy dissipation, and transparent.

[0043] In a routed injury configuration, a rotary, linear, or belt-style electroadhesive clutch 101 is housed in a casing 106, which can be rigid or semi-rigid. The mechanical output of the casing 106 is then mechanically routed to the desired location on the body where injury mitigation is targeted, using a tether 120 and compressive sleeve 121, a belt-and pulley, or other mechanical transmission system. The advantage of this design relative to the unrouted, body-anchor mounted embodiment is that the majority of the device hardware can be mounted in a convenient location that is comfortable, easy to don/doff, does not interfere with adjacent equipment, and limits added mass and inertia on the targeted portions of the body. This strategy of remote mounting also enables free motion of the body by allowing the largest and most rigid portions to be mounted away from biological joints.

[0044] The tether 120 may comprise one or more Bowden cables, which can be used to support a single joint or multiple joints. In some embodiments, two Bowden cables connected to electrostatic clutches 101 can support joints antagonistically to prevent rotation in both directions for a single degree of freedom. In another embodiment of the routed-type device 100, there are multiple outputs, allowing a combination of multiple body parts or multiple degrees of freedom on body parts to be selectively motion-restricted by a single casing 106. [0045] The injury prevention device 100 described herein is applicable in a broad range of applications. It can be used to supply supportive loads to reduce fatigue. It can restrict range of motion to keep joint position within safe bounds or to keep the body within a safe envelope. It can provide resistive loads to dissipate energy and reduce body segment accelerations. It can change modes to provide protection against acute injury to the same users in the event of a collision, fall, high acceleration maneuver or other sudden event. It can provide protection to anyone performing repetitive tasks or working with heavy tools. It can share the burden of near-constant loads such as helmets and head mounted equipment, oxygen tanks etc. In addition to preventing injuries in able bodied persons, the invention can be used to prevent further injury during recovery and rehabilitation after an injury or to reinforce a joint which has never fully recovered.

[0046] Referring again to the figures, Fig. 3 depicts an embodiment of a routed injury prevention device 100. In this embodiment, the electrostatic clutch 101 is mounted to the chest and tethers 120 are routed to the head and ankle. Dotted lines represent the tethers as they wrap around the backside of the body out of view. When used for preventing injury in pilots, the chest attachment could be a torso harness or survival vest, the head attachment could be between a helmet and the torso, the arm attachment could be to a strap, and the ankle attachment could be to a boot. During a cockpit ejection scenario, the injury prevention device 100 connected to the head could prevent neck injury during the catapult and windblast stages of ejection, and the device 100 connected to the ankle could prevent ankle injuries upon landing. In this case, sensors 140 could include an accelerometer that can detect when each of these events has or is about to happen. All of these devices 100 could then allow free motion after these events have passed and the pilot needs to move freely. Additional similar devices 100 connected to joints of the limbs could prevent limb flail during the catapult phase or as a result of wind blast upon hitting the air stream. [0047] In other embodiments, multiple joints may be assisted by multiple injury prevention devices each with their own housing. The electronics and control logic may be shared between devices or may be applied to each in isolation.

[0048] Fig. 4 depicts another embodiment of an electrostatically-activated, routed injury prevention device 100 in isolation from the body -worn garments. In this embodiment, the device 100 comprises a tether 120, a tether conduit 121, a conduit termination attachment 122, a controller 110 (which may include a battery 130 and voltage driver 131), and a housing containing an electrostatic clutch 101 and mechanical components such as a shaft 107, pulley 115, springs 108, bearings and connective hardware. In this embodiment, the housing for the controller 110 also houses a voltage source 130, sensors 140, control circuitry, processors, and voltage driver 131. Alternatively, these components may also be included in the clutch 101 housing. The controller 110 is connected to the electrodes 102 of the electroadhesive clutch 101 and may employ a slip ring or carbon brush to make an electrical connection.

[0049] Alternatively, electrical connection to the rotating elements of the clutch 101 may be enabled by establishing a connection through a clock spring or via a coiled cable. Some embodiments may employ a series electrical configuration between multiple electrodes 102 spanning rotating and non-rotating components. In these configurations, no explicit electrical connection to one set of clutch members 102 is needed. This is particularly beneficial if the stationary set is explicitly connected to the controller 110 via electrical connections such as wires and the moving set is connected only through the clutch interface. In these embodiments, the need for a slip ring, electrical, brush, flex cable harness or other connection strategy to connect to the moving members can be eliminated.

[0050] The logic embedded in the controller 110 takes in sensor data to trigger the activation, deactivation, or voltage modulation of the electrostatic clutch 101. One end of the tether 120 and tether conduit 121 is terminated on the clutch housing. In use, the other end of the tether conduit 121 is connected at the termination attachment 122 to the body on one side of a biological joint or sequential group of joints. The tether 120 is then terminated on the opposite side of the biological joint or sequential group of joints, such that the two attachment points for the conduit 121 and tether 120, which may comprise a cord or cable, span the portion of the body where motion is to be selectively restricted. The body-mounted tether 120 and tether conduit 121 terminations may be attached to the body using a garment, strap, pad, sleeve, armor, MOLLE vest, parachute harness, helmet or other body -worn textile or equipment. The tether 120 and conduit termination attachment 122 may be permanently mounted to one of these body attachments or may be removable by means of an intermediate connector. A non- inclusive list of intermediate connectors follows: MOLLE, hook and loop materials, snaps, zippers, carabiners, latches, buckles, clips, screws, magnets, knots, ties, loops and posts, quick release tether connections such as those used on racing helmets, gecko-like adhesives, or electroadhesive connectors. In this embodiment, the tether 120 is a braided nylon or polymer cord.

[0051] Fig. 5 depicts a housing 106 for the electrostatic clutch 101. The housing 106 includes means for attaching the electrostatic clutch housing 106 to the user. The bottom of the housing 106 includes features that interact with standard US military MOLLE and PALS webbing. Other embodiments may utilize snaps, hook-and-loop fasteners, or other attachment hardware.

[0052] Fig. 6 depicts an alternative embodiment of conduit 121 and tether 120 terminations in which metal tubes have been deformed or crimped over the tether conduit 121. Webbing has been sewn tightly in a loop over the conduit 121 such that it is constrained by the webbing and the crimps prevent the webbing loop from sliding along the length of the conduit 121. The webbing is passed through loops of MOLLE which are sewn onto a parachute harness. The webbing includes two metal snaps that can be folded over and connected to secure the conduit housing 121 to a harness or garment. These snaps do not bear a large load as tension develops in the tether 120. A stiffener is contained in a pocket on the webbing to increase the connection’s ability to withstand large tether loads without significant deformation. The Bowden cable housing 121 may extend past the crimps as shown or may be terminated directly under a crimp. The inner cable of the tether 120 is attached to a buckle clip that is paired with a quick release buckle mounted on a helmet.

[0053] Fig. 7 shows further detail of the embodiment depicted in Fig. 6. As shown in Fig. 7, a section of webbing is sewn or otherwise adhered to a garment in the standard methodology employed in MOLLE and PALS. The dotted lines represent stitching that creates loops in the webbing. The conduit termination attachment 122 is made of webbing or another flexible material. The flexibility enables the attachment 122 to be inserted into the loops in the stitched webbing attached to a garment or harness. A stiffener is contained in a pocket of the conduit termination attachment 122. The conduit termination attachment 122 is stitched such that the middle of the attachment 122 forms a loop of diameter only slightly larger than the diameter of the tether conduit 121. The Bowden conduit 121 is placed in this loop. The conduit termination attachment 122 is prevented from sliding along the length of the conduit 121 by regions of greater diameter. These may be produced by crimping metal tubes or other deformable shapes onto the tether conduit 121. The webbing is passed through loops of MOLLE which are sewn onto a parachute harness. The conduit termination attachment 122 may include snaps, hooks and loops, or other fasteners for retention. The Bowden cable housing 121 may extend past the crimps as shown or may be terminated directly under a crimp. The inner cable of the tether 120 is a nylon rope that is attached to a metal plate that interacts with a quick-release helmet tether. The embodiment depicted in Fig. 7 illustrates the capability of the attachment 122 to rotate with little resistance due to the flexibility of its constituent materials. The stiffener adds selective support to allow this rotation while also limiting translation of the tether conduit 121 in a direction collinear with the tether 120.

[0054] In the routed-type injury protection device 100, the mounting points for the tether 120 end and the compressive sleeve 121 end must be capable of bearing loads equal to the tension on the tether 120.

[0055] The tether 120 may be constructed in a manner that permits small radius bends as this enables free selection of pulley diameter and does not constrain the minimum radius of curvature of the tether 120. The tether 120 may be single strand or braided. Braided polymer tethers 120 provide some axial compliance which reduces shock loads that may be experienced as the electrostatic clutch 101 first engages. A compliant element may be added in series with the tether 120 or shaft to further reduce shock or jerk upon engagement. Other tether 120 materials may include metals such as tungsten wire or braided steel cables.

[0056] Fig. 8 depicts another alternative embodiment where the clutch housing 106 contains multiple clutch modules, which may comprise a set of clutch member 102 pairs arranged in a stacked configuration. The rotating portion of the clutch member 102 connects to a spline feature on a shaft 107. The stationary portion of the clutch 101 interacts with the housing 106 via teeth that fit into a matching recess in the top housing 106. The shaft 107 interacts with a bearing seated in the housing 106. The shaft 107 also includes a spool, or pulley 115, from which the tether 120 is payed out or stored when retracted. Alternatively, the pully 115 may be a separate component from the shaft 107, while sharing a common axis with the shaft 107. The shaft 107 includes an arbor for attachment to a rotary spring 108. The rotary spring 108 is attached to both the shaft 107 and the housing 106 such that the spring 108 supplies more torsional force as the tether 120 extends. The strength and pretension of this spring 108 can be selected to provide only a small retracting force to follow the movements of the user and prevent cable slack or may be selected to provide passive supportive forces. In this embodiment, the device 100 supplies supportive or retracting forces when the clutch 101 is in the disengaged state. When the clutch 101 is engaged, the rotating portion of the clutch 101 is mechanically connected to the stationary portion. This mechanically locks the shaft 107 and dramatically increases the stiffness of the device 100 as experienced by the user. When the clutch 101 is fully engaged at maximum voltage, the device 100 provides restraint. When the clutch 100 is partially engaged at an intermediate voltage, the clutch interface experiences slip and the clutch 101 can provide a tether force that is maintained while the tether 120 extends, providing energy dissipation.

[0057] In other embodiments, a spring 116 may be used to provide a force greater than required to simply retract the cable. This greater force may be used to provide force passively to the user’s body to perform a useful task such as counterbalancing a weight, approximating biological torques or other force or torque profiles. In other embodiments, the passive spring assistance may have a substantially non-linear force-displacement response enabled by the use of non-linear elastic materials, cams, linkages, or other mechanical components that produce non-linear force-displacement response. In another embodiment, multiple clutched springs may be controlled in parallel with one another to tune the level of assistance or the forcedisplacement profile experienced by the user.

[0058] In other embodiments, the electrostatic clutch 101 may be connected in parallel with or in series with an active force producing element such as a motor, linear actuator, solenoid, twisted string actuator, pneumatic device, hydraulic device, fluidic device, or other similar device. When connected in series, the clutch 101 may provide selectable back-drivability or selectable stiffness. Back-drivability refers to the ability to move a joint or an actuator by applying torque or force to the output. In highly geared actuator systems or systems with high friction, back-driving is difficult and the joint or actuator provides lots of resistance to any movement of the output driven by an external source. This is relevant because using a non- backdrivable actuation system would make it much harder for the user to move freely in the 'free movement' mode of the device 100. Selectable back-drivability using a clutch 101 may provide a free-moving or ‘transparent’ user state, while also enabling an assistance mode to activate within milliseconds. This is not achievable by simply using slack in the tension transmission elements because a significant amount of time, on the order of many milliseconds or seconds, can be required for a motor or actuator to fully take up the slack. A single or multiple clutches 101 may be combined in series with an elastic element to reduce the velocity requirements of the actuator. Electrostatic clutches 101 can be used to change the elastic element or number of elastic elements coupled in series with the motor. This allows selection of a combined stiffness that approximates the desired torque or force profile. Smaller movements of the actuator are then needed to fully achieve the desired torque profile. When connected in parallel, the clutch 101 may provide selectable stiffness or actuator assistance when combined with an elastic element. This configuration may enable selection of less capable, smaller or cheaper actuators to perform the same function by sharing the torque or force load.

[0059] Fig. 9 depicts an embodiment in which a source 116 of tether force can be selectively connected to one or multiple tethers 120 selected from a group. The source 116 in this embodiment is a power spring selected to provide counterbalancing forces that scale with tether payout. One end of the power spring 116 is attached to the housing 106, the other end, called the spring output, is connected to the shaft 107. Each tether 120 is connected to a reel, or pulley 115, that is connected in series to a spring. In this embodiment, the spring is a retraction spring that applies a small force to take up slack in the tether 120. Each reel sits on a bearing that interfaces with the shaft 107 such that the reel and the shaft 107 can rotate relative to each other with little resistance. Each reel is connected to the input of an electrostatic clutch 101. The output of each of the reel -mounted clutches 101 is connected to the shaft. When a reel-mounted clutch 101 is engaged, its reel and the user are mechanically connected. When the voltage applied to the clutch is at maximum, the device 100 applies forces to restrain the user. When an intermediate voltage is selected the restraint forces are limited such that the clutch interface may slide and apply a tether force while the tether 120 is extending that can be actively modulated. The load from the power spring may be shared across multiple tethers 120, applied to just one, or none at all depending on the states of the electrostatic clutches 101.

[0060] In other embodiments, the functions of the spring and bearing may be combined into a single component that acts as shaft seat and tether force source. For example, the shaft may have a toothed interface that interacts with teeth on the inner diameter of an elastomeric disk while the outer diameter of this disk is connected to the housing 106 through teeth, adhesives, fasteners or other method. Strain energy in this disk would resist rotation of the shaft and provide a restoring moment.

[0061] In other embodiments the source 116 of tether force may be a damper, active actuator, spring, or other torque-producing element. The spring may be of any construction including but not limited to linear spring, clock spring, power spring, torsional spring, deflecting beam, leaf spring. The spring may be of any material including but not limited to spring steel, natural rubber, synthetic rubber, synthetic elastomer, fiberglass. The action of the spring may be linear stiffening, constant force, non-linear stiffening, softening or any combination of these across the range of its deflection.

[0062] Fig. 10 depicts an embodiment of the device 100 that provides head and neck protection. In this embodiment, the tether conduit 121 is attached to a parachute harness. The harness functions as a parachute harness in all its normal functions and as a mount for the injury prevention device 100. A main function of connecting to the parachute harness is to react forces applied by the tether 120 and conduit 121 across the body comfortably. The inner tether 120 connects to the helmet of the user. The electrostatic clutch housing 106 is mounted remotely relative to the neck, which is the targeted area of assistance. This mounting is convenient as the rigid housing 106 does not interfere with the seat or aircraft restraints. In this embodiment two injury prevention devices 100 are mechanically separate, but share the same controller 110 in order to function collaboratively with each other.

[0063] In this example embodiment shown in Fig. 10, the remote mounted clutch housing 106 includes a spring to provide counterbalancing forces. These counterbalancing forces act in parallel with the neck extensor muscles to support the mass of head mounted equipment. This prevents muscle fatigue and chronic pain. Due to the tether’s greater leverage about the neck as compared to the neck muscles, the force in the tether 120 plus the force in the neck extensor muscles is lower than the unassisted muscles alone. This means intervertebral reaction forces are also reduced by the system. The electrostatic clutch 101 can engage to provide resistance in addition to the counterbalancing spring. At max voltage, the tether 120 cannot extend and dynamic loading experienced by the head resulting from acceleration of the cockpit is reacted through the tethers 120. This prevents large rotations and translations of the head from occurring. This results in lower muscle forces due to stretch reflexes, keeps the head within its safe range of motion, and prevents whiplash. In an alternative embodiment, the multiple injury prevention devices 100 may communicate wirelessly with each other or with remotely mounted sensors 140 and controllers 110.

[0064] Fig. 11 depicts an embodiment of the device 100 leveraging a rigid collar as a structure 118 for tether conduit termination attachment 122. This structure 118 is located between the user and the seat restraints. The head transmits load to the helmet, the helmet transmits load to the inner tether 120. The conduit termination 122 experiences a reaction that is equal and opposite to the tension in the tether 120 and transmits this load to the collar 118. This load is finally reacted out through the seat restraints and compressive loads on the user. The collar 118 may be unattached to the user or may be attached to the user via a strap, harness, snap, hook-and-loop fasteners, MOLLE or other connector or garment for convenience. Any connection between the collar 118 and the user should be compliant in this embodiment as the primary load path is intended to be reacted out through the seat restraints connected to a structure 118 that is not body worn equipment. This device includes a clutch 101 to transition the tethers 120 from locked to sliding or retracting. This provides freedom of motion when protection is not needed and protection only when needed thus overcoming some of the limitations of conventional head and neck protection devices. Changing the state of the clutch 101 could be accomplished manually or controlled by any number of sensors 140 such as accelerometers, encoders or other sensors for sensing rate of extension, vision systems, load cells, G-activated switches or other sensing devices.

[0065] Fig. 12 depicts yet another alternative embodiment in which the injury protection device 100 is a head and neck protection system leveraging the external structure 118 of a seat as a tether conduit termination attachment 122. In this embodiment, the head transmits load to the helmet, the helmet transmits load to the inner tether 120. The conduit termination 122 located on the seat 118 experiences a reaction that is equal and opposite to the tension in the tether 120 and transmits this load to the seat.

[0066] Fig. 13 depicts the device 100 as a head and neck protection system leveraging the seat restraints as an intermediate tether conduit termination structure 119. In this embodiment, the head transmits load to the helmet, the helmet transmits load to the inner tether 120. The conduit termination 119 located on the seat restraints experiences a reaction that is equal and opposite to the tension in the tether 120 and transmits this load to the seat.

[0067] Fig. 14 depicts an embodiment in which a universal clutch 101 is used to establish a restraining connection between the head via a helmet and a seat head rest. This embodiment may be used to provide protection to pilots in the event of an ejection.

[0068] In some embodiments, a stopper 125 can be added to the inner cable 120 at the output end of the tether 120 that prevents further retraction of the inner cable 120 when the stopper 125 encounters the tether conduit 121. The stopper’s location can be used to set the pretension in the max retracted state. The stopper 125 can also be used to strategically cease assistance when the assisted joint reaches a specified angle. When placed on the input end of the tether 120, the stopper 125 can provide a hard stop to prevent continued extension of the tether 120 beyond a desired boundary. This length of extension can be mapped to the joint angle of the user to keep the joint within a desired range of motion. A similar effect may be accomplished in other embodiments by placing a hardstop on the shaft to limit its rotation.

[0069] Fig. 15 shows a Bowden cable with a stopper 125. In the embodiment shown in Fig. 15, the stopper 125 is a metallic cylinder that has been deformed or crimped to establish a mechanical connection to the tether 120 that resists sliding along the tether 120. A similar effect could be achieved by another deformed component such as a staple or folded rectangle, a knot, or even the tether termination component itself. An example of the last item would include a carabiner or buckle clip. [0070] In alternative embodiments, the device 100 is mounted to body anchor points. In this configuration, the sides of the clutch 101 connect more directly to the body anchor points, as opposed to using a transmission to be routed along the body. Compared to the routed device, this embodiment can advantageously have fewer parts, reducing mass, inertia, cost and opportunity for part failure. The body anchor mounted style may be housed in a rigid casing 106 or not.

[0071] Fig. 16 shows yet another embodiment of the device 100 that provides neck injury prevention while still enabling flexibility. The thickness of the injury prevention device 100 is exaggerated for clarity. The clutch 100 is a linear-style clutch and is attached to a strap around the lower back and a tether 120 extends to a helmet to prevent excessive neck flexion. The housing 106 for the linear-style clutch, which includes linear clutch member 102, may include bumpers 126 to retain the clutch members 102 within the housing 106. Because the housing 106 is flexible in this embodiment, the bumpers 126 aid in retention while allowing movement of the clutch 101. Advantages of this embodiment is that a rigid housing 106 is not needed, cost and complexity of the design is reduced, the inertia of the moving portion of the clutch 101 is low as compared to the routed, rotary embodiments described above, and the thinness and semi-compressibility of the clutch housing 106 enables comfort when bending or when sitting in a chair. The disadvantage is that for the same tether force, a larger clutch area is needed as opposed to the rotary, routed version.

[0072] In another embodiment, shown in Fig. 18, the device 100 is attached across the knee from straps on the thigh and the shin to prevent excessive knee flexion as an athlete is performing squats. A sensor 140, such as an EMG (electromyography) sensor, could detect when an athlete is losing strength or is about to fall due to fatigue. In other embodiments sensor 140 could include one or more of the following: goniometer, wearable stretch sensor, camera, IMUs or accelerometers capable of measuring joint angle and velocity. A sensor 140 or combination of sensors 140 could prevent hyperextension or flexion of joints by engaging the clutch 101 to provide added support when boundaries of safe range of motion or joint velocity are approached or exceeded.

[0073] In other embodiments of the device shown in Fig. 16, the standoffs for the housing 106 do not have to be flexible. Bulk flexibility of the housing 106 may still be achieved with rigid standoffs. The regions between standoffs will still maintain flexibility. A similar effect may be achieved by including pin connections between short lengths of the housing 106 in a method analogous to a watch band or cable tracks typically used in CNC applications or 3d printers. [0074] As discussed above, the voltage applied across the electrodes 102 determines the force experienced at the clutch interface. The voltage can be modulated in order to allow some slip at the interface. In this manner of operation, the clutch 101 would experience slip at a lower tether load than the load at which mechanical failure of another component would occur. In this way, the clutch 101 acts as a mechanical fuse to prevent damage to the device 100 itself and to limit the force that the device 100 may apply to a user.

[0075] The springs used in some embodiments can have variable pretension. The pretension of the spring can be adjusted in numerous ways. The spring can be pretensioned with different numbers of initial terns in its retracted state. In one embodiment, dowels or pins inside the housing can be used to modulate the number of coils the spring has in its retracted state or to change the leverage over which the spring can act. The spring is deformed such that the end can be hooked around or otherwise constrained by the dowels. Alternatively, an adjustable spring termination in the housing 106 can be used. In another embodiment, a wrench or screwdriver method from outside housing 106 will allow the spring stiffness to be changed. The wrench or screwdriver may rotate the termination of a rotary spring to increase the number of coils of pretension the spring experiences at max retraction. In other embodiments, the spring may be of types other than rotary. For example, it could be a linear spring or leaf spring.

[0076] The electrostatic injury prevention device 100 has a number of possible modes including but not limited to restrain, absorb energy, support, transparent, and retract. The number and combination of the modes available depends on the number of electrostatic clutches 101 involved and the supporting mechanical structure.

[0077] Fig. 17 shows a flow diagram of the control scheme employed by the controller 110. The control scheme can be used for a clutchable spring for retraction, a clutched support mechanism such as a power spring, and a clutched shaft or tether pulley to restrain the tether 120 from further extension. The device’s default state is to provide support unless a number of other conditions are met.

[0078] At step 201, the controller 110 receives raw data from at least one sensor 140. The controller may perform signal processing to filter the data as needed and performs calculations as necessary to return joint angle, joint velocity, joint acceleration, linear acceleration of the body or vehicle, and any inputs signaling a change in user command. This type of signal processing may also be performed by the sensor 140. At step 202, the controller 110 determines if the body joint has reached the boundary of safe range of motion. If so, the controller 110 send restrains the device 100 and applies a high voltage to the clutch members 102. If not, at step 203, the controller 110 determines if the joint is rapidly approaching a boundary of a range of motion. If so, the device 100 is set to energy dissipation mode. In energy dissipation, the voltage applied to the clutch members 102 is scaled according to joint velocity, joint acceleration, body or vehicle acceleration, and proximity to the range of motion boundary. If not, at step 204, the controller determines if the body or a vehicle is experiencing a high acceleration. High acceleration will engage the energy dissipation mode. If not, the controller 110 determines if a large acceleration is anticipated at step 205. If yes, and the body is in a safe position, energy dissipate mode is engaged. If yes, but the body is in an unsafe position, a retract mode is engaged. If at step 205 a large acceleration is not anticipated and body support is desired, at step 206 support mode is engaged; if not, transparent mode is engaged.

[0079] Joint velocity can be used as a predictive term. If joint velocity is too high and range of motion threshold crossing is anticipated, the device 100 will transition to energy dissipation mode and will engage the clutch at an intermediate voltage to dissipate energy as slip occurs at the clutch interface as a result of tether payout. The magnitude of the applied voltage may be determined by one or a combination of these items on this non-inclusive list: joint velocity, joint acceleration, body acceleration, vehicle acceleration, proximity to a range of motion boundary or others.

[0080] Sensing for mode transition can be accomplished through a wide array of sensors 140 or combinations of sensors 140 or inputs. Some examples include but are not limited to: accelerometers, IMUs, encoders, load cells, goniometer, capacitive flex sensors, force or torque transducers, G activated switches, electromyographic (EMG sensors), heart rate sensors, respirometry, limit switches, string pots, buttons, dials, etc. The sensors 140 may be internal to the device 100 or mounted separately to the user or the user’s vehicle. The sensor data may be integrated or differentiated to use rates of change as a control metric.

[0081] In some embodiments, support mode may be accomplished by using an electrostatic clutch 101 to mechanically couple a supportive force source to a tether 120. These sources may include a number of force producing elements including but not limited to springs, motors, linear actuators and more which may be combined with other mechanical components such as pulleys, belts etc. These sources may be selected and tuned to provide a particular torque profile for a particular task or condition. The degree of support may be controlled by electrostatic clutches 101 used to engage different numbers of force sources. In some embodiments turning off support mode may not be desired. Support mode may be a default mode.

[0082] In some embodiments, energy dissipation mode may involve an electrostatic clutch 101 providing resistive loads while sliding at the interface or may include another force source such as a damper. Energy dissipation mode may be activated by control inputs that indicate or predict the need to reduce or prevent excess kinetic energy of the user, such as velocities that exceed a threshold or high velocity near an injury-prone position.

[0083] Restraint mode may be used to prevent whiplash, limit joint rotation to a safe region, prevent limb flail, or exiting of a limb from a vehicle. Coupling is a version of restraint mode where a body segment is coupled to an external structure to enhance safety. An example would include coupling a helmet to a seat rest to prevent basilar skull fracture.

[0084] Transparent mode is used to eliminate or minimize forces applied to the user by the injury prevention device.

[0085] Retract mode may be used to return the user to safe bodily configuration.

[0086] In some embodiments, the electroadhesive clutch 101 of the device 100 can be controlled automatically by acceleration or orientation activated or G activated switches. In other embodiments the clutch 101 may be controlled intelligently in response to sensor outputs. The controller 110 could use position-based activation, velocity -based activation, accelerationbased activation, or any combination of these with other sensor outputs. Additionally, the controller 110 could be optimized before use or during use with a machine learning technique. A non-algorithmic machine learning control could also be implemented to switch modes based on real-time sensor input. The clutches 101 may be powered by batteries 130 housed in the clutch casing 106 or worn separately. In other embodiments, the clutches 101 may be powered by an energy storage device 130 such as a capacitor in one-time activation events in which the clutch 101 disengages after the stored electrical energy has dissipated.

[0087] In some embodiments described in the present application, the head and neck protection device 100 can be operated in three different modes corresponding to a specified response. These modes and their effects are disclosed in the table below.

[0088] As disclosed herein, numerous control strategies can be employed to operate the device 100. These schemes may comprise: acceleration control, jerk control (change of acceleration), force control, yank control, and rotation control. These control strategies may be used in isolation from each other or in any combination.

[0089] In certain acceleration control embodiments, the acceleration is monitored at the torso and engages the device 100 based on its acceleration via a sensor 140 that monitors each axis of the torso's motion. One example of a sensor 140 comprises an accelerometer, which requires signal processing and computation to determine when to engage the system. Another example of sensor 140 used for acceleration controls comprises an omnidirectional G activated switch (omni directional or single axis) which completes a circuit when a threshold G force is hit engaging the device.

[0090] In one embodiment of a jerk control scheme, the device 100 will stiffen to provide support if a threshold is exceeded. An accelerometer may be used to measure acceleration and its rate of change may be calculated. A measure has been defined and called Modified Jerk or Jm.

, where atorso is the acceleration of the torso and C is a time constant. When Jm exceeds a threshold, the electrostatic clutch 101 will engage with a voltage scaled in accordance with Jm. An additional term may be added to scale engagement with joint position in addition to Jm.

[0091] In certain control schemes, the device 100 (dis)engagement may respond to change in force. In instances where the high accelerations are detected, the electroadhesive clutch 101 can engage to provide support. Conversely, force in the device 100 should decrease when support is no longer needed. When decreasing force is detected, the clutch 101 may disengage, or reduce the applied voltage to reduce the resistance that the device 100 applies.

[0092] As used herein, yank is defined as the rate of loading experienced by the injury protection device 100. The force that the electrostatic clutch 101 will support is dependent on the voltage applied. In one control scheme, a low voltage can be applied at the beginning of engagement and increased to reduce the rate of loading of the head (or yank). Separately, monitoring force in the device 100 and its derivative, yank, may allow the device 100 to appropriately ramp the electrostatic force to reduce yank on the body.

[0093] In another embodiment, a position-based control scheme may be utilized by the controller 110 to (dis)engage the device 100. Applying sensors 140 to monitor tether payout will allow the rate of payout to be determined. The rate of extension of the tether 120 can be monitored by an encoder on the clutch shaft or by other means. This measurement can be taken in concert with accelerometers on the torso. If the tether cables 120 are extending, and only low acceleration is detected, it can be assumed that the pilot is moving their head voluntarily. The clutch 101 will not engage. If large acceleration is measured and the tether cables 120 are extending rapidly, the clutch 101 will engage. This scheme allows each device 100 to be activated individually to provide support when needed and freedom of movement when it is not. Monitoring the payout of the tether cables 120 can also provide information on the position of the head. This information can inform the degree of assistance that is applied. For example, the device 100 may modulate support by applying small voltage and therefore small supportive loads when the head is near neutral posture, support can be increased as the head nears the boundaries of its safe range of motion.

[0094] When used in this specification and claims, the terms "comprises" and "comprising" and variations thereof mean that the specified features, steps, or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components. [0095] The invention may also broadly consist in the parts, elements, steps, examples and/or features referred to or indicated in the specification individually or collectively in any and all combinations of two or more said parts, elements, steps, examples and/or features. In particular, one or more features in any of the embodiments described herein may be combined with one or more features from any other embodiment(s) described herein.

[0096] Protection may be sought for any features disclosed in any one or more published documents referenced herein in combination with the present disclosure. Although certain example embodiments of the invention have been described, the scope of the appended claims is not intended to be limited solely to these embodiments. The claims are to be construed literally, purposively, and/or to encompass equivalents.

Claims

CLAIMS What is claimed is:

1. A device that is adapted for attachment to a body of a user comprising: an electrostatic clutch; at least one connection point coupling the electrostatic clutch to the body; and a controller, wherein the controller operates the electrostatic clutch in a first mode to permit substantially free and unencumbered movement of the body.

2. The device of claim 1, wherein the controller operates the electronic clutch in a second mode adapted to apply a force or torque to the body to stop or slow undesired movement of the body, support substantially constant loads on the body, or act to position the body in a safe configuration.

3. The device of claim 1, further comprising: a tether connected at a first end to the electrostatic clutch and connected at a second end to the body.

4. The tether of claim 3 further comprising: a tether conduit; and a conduit termination attachment.

5. The device of claim 1, wherein the electrostatic clutch has rotary clutch members.

6. The device of claim 5, wherein the electrostatic clutch comprises: a housing; a shaft; and a spring connected to at least one of the shaft and a first rotary clutch member.

7. The device of claim 6 further comprising: a tether pulley; and a mechanical connection between the spring and the tether pully.

8. The device of claim 7, wherein the clutch has a nested configuration.

9. The device of claim 8, wherein the clutch further comprises the housing or a portion of the housing.

10. The device of claim 7, wherein the electrostatic clutch comprises a plurality of clutch members stacked in separate layers.

11. The device of claim 5 further comprising: a plurality of tethers, wherein each tether of the plurality of tethers is connected to a tether connection pulley; and an assistance source connected to at least one tether of the plurality of tethers, wherein the assistance source comprises an actuator, damper, spring, or other force- or torque-producing mechanism.

12. The device of claim 1, further comprising: an actuator, damper, spring, or other force- or torque-production component that is selectively coupled to the body through the electrostatic clutch.

13. The device of claim 1, further comprising: an actuator, damper, spring, or other force- or torque-production component that acts in parallel with the electrostatic clutch.

14. The device clutch of claim 11 further comprising: a bearing separating adjacent tether connection pulleys.

15. The device of claim 11, wherein each tether of the plurality of tethers is routed to a separate area of the body.

16. The device of claim 11, wherein each tether of the plurality of tethers is routed to a single segment of the body to prevent multiple modes of injury.

17. The device of claim 1, wherein the electrostatic clutch has linear clutch members.

18. The device in claim 17 further comprising: a top housing; a bottom housing; a plurality of bumpers disposed on at least one of the top housing and the bottom housing to retain the linear clutch members; and a harness attachment mechanism.

19. The device of claim 17, further comprising: a housing.

20. The device of claim 19, wherein the housing is flexible.

21. The device of claim 20, wherein the housing comprises a flexible material.

22. The device of claim 20, wherein the housing comprises rigid or semi-rigid materials with intermittent cuts, notches, v-shaped exclusions, or similar features that enable out-of-plane deformation.

23. The device of claim 18, wherein the linear clutch members are selectively attached to the top housing, the bottom housing, or connection points.

24. The device of claim 18, wherein at least one clutch member of the clutch members has a length spanning all or most of the length of the top housing or bottom housing, such that an overlap area of the clutch members is substantially constant throughout the full displacement of the electrostatic clutch.

25. The device of claim 4, wherein the conduit termination attachment and the tether are both terminated on structures that are worn on the body.

26. The device of claim 4, wherein the tether is terminated on a rigid structure located between the body and restraints connected to a structure that is not body worn, such that all or a portion of the load applied to the rigid structure is reacted out through the restraints and not through body worn components.

27. The device of claim 4, wherein the tether is attached at one end to a structure that is not worn on the body and the tether is attached at a second end to an external structure.

28. The device of claim 27, wherein the tether is attached to an intermediate structure located between the body and the external structure.

29. The device of claim 1, wherein the electrostatic clutch comprises universal clutch members, wherein at least one clutch member of the clutch members is disposed on the body and at least one clutch member of the clutch members is attached to an external structure, such that activating the clutch creates a mechanical connection between the body and external structure.

30. The device of claim 6, wherein the housing further comprises attachments suitable for use with MOLLE attachments.

31. The device of claim 4, wherein the tether comprises an attachment mechanism at one end adapted to connect to a MOLLE attachment.

32. The device of claim 31, wherein the MOLLE attachment comprises a change in a diameter of the tether conduit and a connector that is retained between at least two larger diameter members.

33. The device of claim 31, further comprising a flexible fabric and stiffener to allow rotation but not translation of the tether termination attachment.

34. The device of claim 33, wherein the stiffener is removable to enable donning and doffing of the device.

35. The device of claim 4, further comprising a stopper attached to the tether to restrict a range of motion of the device or a range of motion of the body.

36. The device of claim 6, further comprising: a hard stop applied to the shaft or pulley to restrict the range of motion of the device or the range of motion of the body.