Electrically controllable injury prevention device

Abstract

An injury prevention device utilizes electrostatic clutches to selectively engage various components of the device. The device can be incorporated into safety equipment and permits free movement of the user in one mode of operation while preventing excessive movement in another mode of operation. To prevent movement, an electrostatic clutch is connected to a cable or tether, which can be connected to the user's helmet or other equipment.

Description

TITLEELECTRICALLY CONTROLLABLE INJURY PREVENTION DEVICECROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit under 35 U.S.C. § 119 of U.S. Provisional Application Serial No. 63 / 745,775, filed on January 15, 2025, which is incorporated by reference herein.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] Injury prevention devices include largely passive or one time use devices such as seat belts, arm restraints, arm restraints and air bags. Recently, exoskeletons have been growing in popularity and include both passive and powered systems. These systems limit range of motion, dissipate kinetic energy, or provide assistive forces to offset a load applied to a user.

[0004] In prior systems the majority of exoskeleton systems are either powered or passive. Powered systems are capable of performing net positive work on the user using motors or other actuators. Powered systems can be heavy, limiting their usefulness in certain applications. Passive systems utilize springs to perform net zero work on the user by straining and releasing elastic elements such as springs. While lighter, passive systems are either very simple or “dumb” meaning that they must be engaged or disengaged manually. Powered systems often include complex sensing to enable them to be “smart”. Other safety mechanisms such as seat belts, HANS devices, and arm restraints are simple and effective for mitigating risk in a high G event, but they are not smart devices capable of providing variable assistance or personalized assistance. It would therefore be beneficial to develop an injury prevention device that is capable of providing lightweight, smart control.BRIEF SUMMARY

[0005] An injury prevention device uses electroadhesive clutches in a novel configuration to enable automatic transitions between modes of operation within an assistive device without the use of bulky motors, solenoids, or other actuators. The use of electroadhesive clutches enablesa passive system to exhibit “smart” behavior previously impossible or impractical using traditional methods of selective mechanical couplings. The injury prevention device disclosed herein is a quasi-passive device capable of transitioning between assistive modes based on sensor readings without significant power input. In addition to being power efficient, the device is also more compact, lightweight, and thermally cooler than previous systems. Lastly, due to the low power nature of the device, negligible electromagnetic interference is generated by the device.

[0006] Electroadhesion is a voltage driven phenomenon that does not require large current input of the magnitude required by conventional clutch solutions. This makes electrostatic clutches intrinsically more power efficient than current-driven electromagnetic devices for the same performance. They also do not require compressors and are simpler to implement than pneumatic or hydraulic solutions. In addition to being more power efficient, electrostatic clutches are also more compact because the electrodes can be incredibly thin as opposed to electromagnetic coils that are large and heavy with minimum sizes limited by resistive heating, wire gauge, and the number of loops.

[0007] In all configurations, an electrostatic clutch 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 (5) altering the connections within a drive train to adjust speed and maximum force output. Cost effective solutions exist, but they fail to deliver high force accuracy and precision, lack the ability to be adjusted in real time electronically, are too bulky, or too power hungry to be effective in compact or mobile applications. In most cases, an electrostatic clutch could provide benefits over existing solutions in one or more of the following areas: improved precision and accuracy of force limitation, compactness, reduced overall weight, increased energy efficiency, improved controllability and responsiveness, reduced complexity and number of components, reduced heat production, and reduced cost.

[0008] Electroadhesives can be used in a wide variety of exoskeleton applications to prevent injury from a broad range of sources. Almost any system in which mechanical connections need to be established and released in a controllable way can be improved by the use of electroadhesives.BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0009] Figs. 1 A-1C show different views of an embodiment of the injury prevention device.

[0010] Fig. 2 shows the principle of electrostatic adhesion in an electrostatic clutch.

[0011] Fig. 3 shows a cross section of an embodiment of the injury prevention device.

[0012] Fig. 4 shows an exploded view of the lower housing of an embodiment of the injury prevention device.

[0013] Fig. 5 shows an exploded view of the upper housing of the injury prevention device.

[0014] Fig. 6 shows a mechanical diagram describing an embodiment of a linear version of the injury prevention device.

[0015] Fig. 7 shows an output selector comprising electroadhesive clutches, tensioners, and a forked tether input.

[0016] Fig. 8 shows two options for reducing the amount of tether travel within the injury prevention device without reducing the maximum payout length of the output tethers.

[0017] Fig. 9 shows the front view of a clutch assembly comprised of electroadhesive clutches and tensioners. The state of the clutches determines the operational mode of the device.

[0018] Fig. 10 shows the side view of a clutch assembly comprised of electroadhesive clutches and tensioners. The state of the clutches determines the operational mode of the device.

[0019] Fig. 11 shows a mechanical diagram of an embodiment of a linear version of the injury prevention device in which multiple tethers connect to the output of the device, are each routed through a gearbox, and then an output selector selectively connects the gearboxes to a counterbalance system.

[0020] Fig. 12 shows an embodiment of the injury prevention device in which each tether is connected directly to a gearbox, clutch assembly, and counterbalance system without the use of an output selector.

[0021] Fig. 13 shows an embodiment of a counterbalance mechanism using a spring motor and capstan to enable near constant force on the output tether.

[0022] Fig. 14 shows an embodiment in which a single output tether exits the clutch and counterbalance assembly as a flexible Bowden cable. The Bowden cable housing terminates on a sliding element mounted to a rigid collar that is worn around the neck of the user.

[0023] Fig. 15 shows an embodiment of an injury prevention device in which the clutch assembly and counterbalance mechanism is mounted to a structure adjacent to the user. The cable is terminated on a helmet or cap with a swiveling rail.

[0024] Fig. 16 shows a detailed image of the swiveling and sliding tether termination which can be attached to a helmet or cap to ensure near constant direction of assistive force regardless of head orientation.

[0025] Fig. 17 shows an electroadhesive injury prevention device used to retract the head into a braced position and couple the helmet to the seat rest and subsequently decouple the head from the seat rest.

[0026] Fig. 18 shows an external view of a back-mounted injury prevention device.

[0027] Fig. 19 is an exploded view of the back-mounted injury prevention device utilizing a synthetic rubber rod as the counterbalance mechanism.DETAILED DESCRIPTION

[0028] The injury prevention device 100 comprises an injury prevention module 112 and flexible tethers 120, such as Bowden cable tethers. The tether 120 is used to apply assistive forces to a user wearing the injury prevention device 100. These forces originate in the injury prevention module 112 which includes one or multiple electroadhesive clutches 101 which determine the operating mode of the device 100. The operating mode of the device 100 can be set manually or automatically given readings from sensors 140 associated with the device 100 or attached to the user. The injury prevention module 112 may be mounted on the user’s garments, restraints, or body harness or it may be mounted remotely on an adjacent structure.

[0029] The injury prevention module 112, as shown in Figs. 1A-1C, comprises one or more clutches 101 with an output shaft 107 adapted to be connected to the tether 120. Within the injury prevention module 112, one set of clutch members 101 are connected to the housing 106 and opposing members 101 are connected to the shaft 107. In this configuration, engagement of the clutch 101 selectively couples the tether 120 to the housing 106.

[0030] Electrostatic clutches 101 use two or more electrodes 102 separated by a dielectric material 103 that attract each other when voltage is applied, creating a controllable normal force that resists motion through direct adhesion or resulting friction. These electrodes 102 — which alternatively may be referred to as “clutch members” when part of a clutch unit 101 — may be simple conductive plates or more complex assemblies combining electrically conductive materials, carriers, and structural materials, and they define the clutch interface where adhesion occurs. A single electrostatic clutch unit 101 can function independently or be combined with additional units 101 to meet force or torque requirements. Depending on their design, electrostatic clutches 101 may act linearly, rotationally, or in a universal manner,resisting motion in shear, normal, or multiple directions. Fig. 2 shows a basic electroadhesive clutch, which is known in the art.

[0031] In one embodiment, the injury prevention device 100 utilizes electroadhesive clutches 101 in a new configuration to enable automatic transitions between modes of operation within the assistive device 100. The use of electroadhesive clutches 101 enables a passive system to exhibit “smart” behavior previously impossible or impractical using traditional methods of selective mechanical couplings. It is a quasi-passive device 100 capable of transitioning between assistive modes based on readings from sensors 140 without significant power input. In addition to being power efficient, the device 100 is also more compact, lightweight, and thermally cooler than previous systems. Lastly, due to the low power nature of the device, negligible electromagnetic interference is generated by the device. The device may include rotary electroadhesive clutches or linear electroadhesive clutches.

[0032] An embodiment of the rotary version of the device 100 is shown in Figs. 1A-1C. This device includes a Bowden cable tether 120 with a housing and inner cable, and a housed injury prevention module 112. Fig. 3 shows a cross section of this module 112. In this embodiment, the injury prevention module 112 is comprised of a counterbalance mechanism 113, clutches 101, shafts 107, housing components 106, connective hardware, sensors 140, electronics, such as a controller 110, batteries and environmental sealing components. The module 112 shown in Fig. 3 is capable of transitioning between three core modes as enabled by three separate electroadhesive clutches 101 contained within the housing 106. The first mode is counterbalancing. In this mode, the output shaft 107 with integrated capstan is coupled to the counterbalance shaft (or counterbalance mechanism 113) which is connected to the output of a power spring 116 (as shown in Figs. 4-5). The first electroadhesive clutch 101 determines whether or not the counterbalancing shaft 113 is mechanically coupled to the output shaft 107.

[0033] When this clutch 101 is in the engaged state, or ‘on’, the output shaft 107 is mechanically coupled to the counterbalancing shaft 113 and spring 116. When this clutch 101 is in the disengaged state, or ‘off, the output is not coupled to the spring 116. In counterbalancing mode, the spring 116 acts to retract the output tether 120 which applies an assistive load to the user. The second mode is locked. In this mode, a rotary electroadhesive clutch 101 mechanically connects the output shaft 107 to the injury prevention module housing 106. In this mode the output tether 120 cannot extend. The last mode is transparent mode. In this mode the output shaft 107 is mechanically decoupled from both the housing 106 and the counterbalancing mechanism 113. In the embodiment presented in Figs. 1 A-1C, 3, 4, and 5 the counterbalancing spring 116 is mounted in a ratcheting spring case. The outer diameter of thespring 116 is attached to the spring case and the inner diameter is mechanically connected to the shaft of the counterbalance mechanism 113. When the injury prevention module 112 is in transparent mode, an electroadhesive clutch 101 couples the counterbalancing mechanism 113 to the module housing 106. This prevents the spring 116 from unwinding while allowing the tether 120 to go slack. The outer diameter of the spring 116 is prevented from unwinding by a ratchet and pawl that only allows rotation of the spring 116 in the tightening direction. This mode can also allow the user to change the level of spring assistance. The user may wind the spring case for increased tension.

[0034] A summary of the clutch states that enable each of these modes is described in Table I.Table IOperational mode Locking clutch Output shaft clutch Counterbalance clutch Counterbalancing OFF ON OFFTransparent OFF OFF ONLocked ON ON OFFSpring tensioning OFF ON OFF

[0035] In this embodiment, electrical connections are established within a lower electronics enclosure where the master printed circuit board (PCB) is mounted. The electronics and connections form a controller 110. This controller 110 is connected to a battery or power source that powers the device 100. Power to the lock-mode electroadhesive rotary clutch 101 is established through pogo pin connections to the master PCB board. These connections include power for the lock mode electroadhesive clutch 101 and also power for additional clutches 101. The shaft coupling clutch 101 is mounted to the counterbalance mechanism 1 Band its output is connected to the output shaft 107. The shaft coupling clutch 101 receives power from the locking clutch 101 through electrical spring finger contacts which are disposed on the top of the locking clutch 101. These electrical spring finger contacts contact a slip ring surface on the bottom of the shaft coupling clutch 101 such that the electrical connection is continuous as the shaft coupling clutch rotates. Pogo pins are disposed on the bottom surface of the spring-to-housing clutch. These pogo pins extend downward and connect to the master PCB for power. Figs. 4-5 depicts an exploded view of this embodiment and shows the locations of these electrical connections.

[0036] In this embodiment, power to each of the electroadhesive clutches comes from a power source which may include a voltage converter, which steps the battery voltage up from low voltage to high voltage (1-50V converted up to 50 to 500 V). Alternatively, high voltage can be supplied directly to each of the electroadhesive clutches 101 from a power source. The highvoltage output of the voltage converter is connected to a series of H-bridges which route power to the clutches. When the clutches are disengaged, the H bridges connect the terminals of the clutch electrically such that no voltage potential can exist between them. In some embodiments a motor is used to add tension to the counterbalancing mechanism 113. The motor may be coupled to the spring case via gearing. In other embodiments, tensioning may be accomplished manually by turning of a knob that is directly connected to the spring case or is connected to the spring case by gearing to enable the spring case to experience turns as a multiple of the turns of the tensioning knob.

[0037] In some embodiments, locked mode may couple the output shaft 107 to a separate ratcheting spring mechanism instead of coupling the output shaft 107 to the housing 106. This will enable the device 100 to retract the output tether 120 while in locked mode should slack accrue while still preventing the output tether 120 from extending while in locked mode. In some embodiments, this ratcheting spring mechanism may be activated by disengaging an electroadhesive clutch 101 that prevents its retraction by coupling it to the housing 106 of the module 112. In other embodiments another hold-down release mechanism may be used such as a pyrotechnic release, spring-loaded release, burn wire mechanism or magnetic release mechanism. This behavior is similar to that of a seat belt when high deceleration activates the seat belts retraction and locking mechanisms.

[0038] In some embodiments, idlers 127 may be used to prevent rubbing of the tether 120 on the Bowden cable entrance or exit.

[0039] In some embodiments, accelerometers may be used as sensors 140 for sensing the acceleration of the torso or other body parts and an encoder capable of sensing the rotation of the output shaft 107 and therefore also the length of extension of the output tether 120 as well as the rate of extension or retraction of the tether 120.

[0040] The device 100 is capable of automatically transitioning between these modes in response to readings from the sensor 140 or in response to user input. In this embodiment, counterbalancing mode is the default mode. The device 100 enters this mode upon powering up. The user may adjust the spring tension and the device 100 is ready for use. The device 100 can be programmed to transition out of counterbalancing mode and into transparent mode if tether payout velocity exceeds a threshold and torso acceleration is below a threshold, for example. This indicates that the user is voluntarily moving their head rapidly under low acceleration conditions. The device 100 can transition back into counterbalancing mode either as indicated by a button press or as otherwise indicated by sensors 140. The orientation of the user’s joints can be intuited by the length of payout of the device’s tether 120 or tethers 120.The device 100 may transition to locked mode to prevent the user from exceeding a safe range of motion using encoder position and rate of rotation. The device 100 may also be programmed to enter locked mode should acceleration exceed a threshold. When in locked mode, the electroadhesive clutches 101 will resist payout of the output tether 120 until the maximum holding torque of the clutch 101 is exceeded and the clutch 101 slips. This behavior can be used to absorb energy in the event of a high G experience (i.e. excessive acceleration), whip lash, or wind blast. The device 100 transitions out of locked mode when acceleration falls below a threshold and remains below for a duration of time. Locked mode may also be initiated by additional sensor readings. For example, a combination of acoustic sensing and pressure sensing may indicate that the canopy of a fighter jet has been released or damaged and that ejection from the aircraft is imminent which should initiate locked mode.

[0041] Injury prevention devices 100 using several electroadhesive clutches 101 to enable mode transitions are valuable in many applications, but take up volume and are rigid. These devices 100 are best suited to applications in which the user is not overly encumbered by other worn equipment or in scenarios where the injury prevention module 112 can be mounted off of the user. In certain scenarios the device 100 can be mounted on or within a seat. The rotating elements allow the device 100 to be relatively compact in terms of the surface area of the mounting surface and can allow large extensions of the output tether 120. A linear version of the device 100 using linear clutches instead of rotary clutches 101 will have a different device envelope and may exhibit lower inertia and overall weight due mainly to the exclusion of shafts, the use of lighter electroadhesive clutches, and the use of elastomer springs.

[0042] Fig. 6 is a diagram describing an embodiment of an injury prevention device 100. This mechanical diagram can describe either a rotary or linear device 100. This device 100 may comprise one or multiple tethers 120. In the case of multiple tethers 120, the state of each tether 120 may be determined by an output selector 145 which uses electroadhesive clutches 101 to selectively mechanically couple each tether 120 to additional components. These additional components may include a gearbox 114, tensioners, and a counterbalance mechanism 113. The gearbox 114 may enable a reduction in the rotation or linear translation of internal components relative to the translation of the output tether 120. This gear reduction enables the use of clutches 101 with shorter overall travel at the cost of needing additional holding strength in the clutch for the same output force. The clutch assembly determines which operational mode the device experiences. These modes may include one or multiple of the following: locked or energy dissipating, counterbalancing, and transparent.

[0043] Fig. 7 shows an embodiment of an output selector 145 comprising linear electroadhesive clutches 101, tensioners, and a forked tether input.

[0044] Fig. 8 shows two embodiments of gear reduction mechanisms 114. Gear reduction here can refer to the ratio between input and output tether 120 travel. The first mechanism 114 comprises a pulley of two diameters onto which cable spools. The output tether 120 wraps around the portion of the pulley that has a larger diameter and the input tether 120 wraps around the smaller diameter portion. For each rotation of the pulley the output pays out more tether 120 than the input reels in. The input and output can be reversed in alternative embodiments. Another option for gear reduction is the use of a floating pulley. Similarly, the length of tether 120 that pays out from this device is twice as long as the travel of the floating pulley. The ratio of tether payout and take up can be adjusted by changing the ratio of the radii of the pulley, by including more stages in the gear box 114, or by using a block and tackle with a greater number of pulleys and tether loops.

[0045] Fig. 9 shows the side view of an embodiment of the device 100 with a clutch assembly that determines the operational mode of the device 100 depending on the state of electroadhesive clutches 101. In this embodiment, the output tether 120 is connected to a clutch member 101 that is substantially shorter than its mating clutch members 101. This shorter clutch member 101 is connected to the device output tether 120 and to a light tensioning spring that prevents the output tether 120 from going slack. The longer clutch member 101 is coupled to the device housing 106 via a light elastic element for alignment and to a counterbalance mechanism 113. When this clutch member pair is active and engaged, the output tether 120 is mechanically coupled to the counterbalance mechanism 113. When this clutch member 101 is disengaged, the output tether 120 experiences the force of the light tensioning spring. An additional clutch member 101 is disposed on the reverse side of the short output clutch member 101. This third clutch member 101 interacts with an additional clutch member 101 disposed on the housing 106 or comprising the housing 106. When the short clutch member 101 is engaged with the housing clutch member 101 the output tether 120 becomes locked and cannot extend unless the applied load on the output exceeds the maximum capacity of the clutch member pair. In some embodiments engaging the housing clutch member 101 at high voltage locks the tether 120 while engaging the housing clutch member 101 at low voltage results in energy dissipation when forces on the output tether 120 exceed the maximum holding capacity of the housing clutch member 101 at the applied voltage, permitting slippage along the long clutch member 101. The input tether 120 to the injury prevention module 112 may include a crimp or knot that cannot pass through the aperture of a stopper structure. The input tether 120 may be optionallyrouted over a pulley before entering the counterbalance mechanism 113. Fig. 10 shows a front view of an embodiment of the injury prevention module 112 depicted in Fig. 9.

[0046] Fig. 11 depicts another embodiment in which each tether 120is connected to a gearbox 114 or travel reducer. The gearbox 114 or travel reducers are disposed between the device’s tethers 120 and the output selector 145.

[0047] Fig. 12 depicts another embodiment in which each individual tether 120 is connected to a gear box 114 or travel reducer, a clutch assembly 101 and a counterbalance mechanism 113. No output selector 145 is used in this configuration. Instead, each tether 120 is connected to its own injury prevention module 112 and can be used independently or with additional modules 112. These modules 112 may be connected electronically or via wireless signals to coordinate mode transition with each other or to share sensor data.

[0048] Fig. 13 is an embodiment of a counterbalance mechanism 113 comprising a spring motor with integrated capstan. A constant force spring wrapping on and off two barrels enables a near constant force output on the tether 120.

[0049] Embodiments which utilize linear clutches will typically experience lower inertia, thickness, and overall mass than embodiments utilizing rotary clutch members. However, the linear embodiments require more overall surface area on which to be mounted. The linear design is well suited for applications in which large flat surfaces are present and available.

[0050] Fig. 14 shows an embodiment in which a single output tether 120 exits the clutch 101 and counterbalance assembly 113 as a flexible Bowden cable. The Bowden cable housing terminates on a sliding element mounted to a U-shaped rail 150 that wraps around user’s neck by at least 45 degrees. The rail 150 is mounted to a rigid collar 151 that is worn around the neck of the user. The Bowden cable end is free to slide such that it follows the back of the user’s helmet 153 near which the inner cable of the Bowden cable is disposed. Seat restraints wrap over the rigid collar 151. Grooves in the rigid collar 151 capture seat restraints to ensure it remains between the user and the seat restraints. Figs. 18-19 show the details of an injury prevention module 112 that can be used in the embodiment depicted in Fig. 14. As shown in Figs. 18-19, the module 112 is flexible and can bend with the user’s back.

[0051] Fig. 15 depicts another embodiment of the injury prevention device 100 in which the injury protection module 112 is not body worn, but mounted on a structure near the user. In this embodiment the tether 120 of the injury prevention device 100 terminates on a sliding element 160. This sliding element 160 is mounted to a curved rail that is mounted to a helmet 153 or cap by a swivel connection 161. This ensures that regardless of the orientation of the user’s head and neck, the assistive force from the injury prevention device 100 acts primarilyin the vertical direction without imparting a substantial twisting torque on the user’s head. An adjustable nape strap and chin strap help ensure that the assistive loads are applied to the user without removing the helmet 153. The helmet or cap 153 may optionally include an integrated headset with speaker and microphone. It may also optionally include an oxygen mask or face shield. Fig. 16 shows a detailed image of the helmet or cap 153 with a swiveling and sliding connection 160.

[0052] Fig. 17 shows an electroadhesive injury prevention device in which a tether 120 is connected to a user’s helmet or cap 153 and to an inertial reel. During the event of ejection from an aircraft it is common for the shoulder restraints to be pulled tight by an inertial reel. However, the pilot's head remains unsupported. This is especially dangerous if the pilot is unconscious. The injury prevention device 100 can be used to pull the head into the braced position prior to ejection. The tether 120 is attached to the parachute harness, seat back, or flight jacket using low strength connectors such as light sticking, hook and loops straps or snaps. When the inertial reel is activated, the tether 120 is pulled free from these light restraints and the head is pulled into position as slack is taken up by the inertial reel. The helmet 153 is then connected to the head rest using a universal electroadhesive clutch 101. The helmetmounted clutch member 101 is double sided. One side connects to the tether 120, the other connects to the helmet 153. When the inertial reel is activated, power to the helmet-mounted clutch member 101 is disrupted by an electrical connection that is pulled free. The clutch member 101 attached to the tether 120 and the clutch member 101 attached to the helmet 153 begin to lose voltage across their interface through leakage current. The connection weakens with time and eventually the clutch falls free from the helmet 153. The time this process takes can be selected through selection of a bleeder resistor. This ensures that the head separates from the seat prior to seat separation in which the pilot falls free of the seat.

[0053] The injury prevention device 100 may be paired with existing safety equipment including but not limited to as seat restraints and harnesses. The embodiment presented here can bemounted directly to a parachute harness or survival vest. The bottom cap of the device can be replaced to include different mounting methods. This embodiment includes four threaded holes for mounting directly to a parachute harness using a pre-existing bracket. Other embodiments may include a dove tail connector, other threaded patterns, MOLLE connectors or other connectors.

[0054] In some of the embodiment presented here, two of the injury prevention modules 112 can be mounted on the torso of the user on the front of their parachute harness. The Bowden cable housing wraps from their chest around their back and is fixed on the parachute harnessto the left and right of the head approximately half-way between the sagittal plane and the farthest extent of the shoulder when arms are at rest to the side of the user. The inner tether 120 extends out from the Bowden cable housing and is terminated on the helmet 153. In this embodiment both inner Bowden cable tethers 120 terminate in the same position on the back of the helmet 153. The termination is a quick release mechanism commonly used in motor sports as a connector for the tethers of a HANS device.

[0055] The injury prevention device 100 may be applied to protect pilots from neck injury. Counterbalance mode can be used to counterbalance heavy, front loaded head mounted equipment such as night vision goggles or heads up displays. Locked mode may protect the neck by redirecting inertial loads from the head to the torso thus circumventing the neck. Transparent mode allows the pilot to make quick voluntary head movements without the resistance of the inertia of the device’s moving components.

[0056] Similarly, this device 100 may be used to protect anyone who uses heavy head mounted equipment or is required to hold awkward postures for long periods of time. These uses include but are not limited to fixed wing pilots, rotary wing pilots, boom operators on refueling aircraft, flight nurses, gunners on military helicopters, search and rescue teams, race car drivers, and surgeons. The device 100 may also be applied to joints other than the neck and may assist in rehabilitation or strength augmentation for construction workers, warehouse workers, first responders and others. In many of these applications, the controller 110 can activate different modes of the device 100 based on voice or gesture command. Alternatively, the controller 110 can interface with other electronic devices, such as a smartphone, to control the device 100.

[0057] 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.

[0058] 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.

[0059] 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

CLAIMSWhat is claimed is:

1. An injury prevention device comprising:a plurality of clutch members comprising a pair of opposing conductive surfaces separated by a dielectric material,wherein the clutch members are configured to form an electroadhesive clutch when a voltage is applied across the pair of opposing conductive surfaces;an output shaft;a tether at least partially spooled around the output shaft; anda counterbalance mechanism connected to at least one clutch member of the plurality of clutch members; anda controller operatively connected to the plurality of clutch members;wherein the controller selectively activates the plurality of clutch members to place the tether in one of a plurality of operating modes comprising:a locked mode in which rotation of the output shaft is resisted; and a counterbalanced mode in which the output shaft is operably connected to the counterbalance mechanism.

2. The injury prevention device of claim 1, wherein the plurality of operating modes further comprises:a transparent mode in which the output shaft is mechanically decoupled from both the housing and the counterbalance mechanism.

3. The injury prevention device of claim 1, wherein the locked mode fully resists rotation of the output shaft.

4. The injury prevention device of claim 1, wherein the counterbalance mechanism comprises a spring imparting a rotational force on the output shaft.

5. The injury prevention device of claim 1, wherein at least one clutch member of the plurality of clutch members comprises a locking clutch configured to selectively couple the output shaft to a housing of the device.

6. The injury prevention device of claim 1, wherein at least one clutch member of the plurality of clutch members comprises a counterbalance clutch configured to selectively couple the output shaft to the counterbalance mechanism.

7. The injury prevention device of claim 1, wherein at least one clutch member of the plurality of clutch members comprises a spring-to-housing clutch configured to selectively prevent release of spring tension of the counterbalance mechanism when the device is in the transparent mode.

8. The injury prevention device of claim 1 further comprising:one ore more sensors, wherein the controller is configured to automatically transition between the locked, counterbalancing, and transparent modes based on data obtained from the one or more sensors.

9. The injury prevention device of claim 8, wherein the one or more sensors comprise an accelerometer, a position encoder, or a tether payout velocity sensor.

10. The injury prevention device of claim 4, wherein the counterbalance mechanism comprises a power spring, a constant-force spring, or an elastomeric spring.

11. The injury prevention device of claim 1, wherein the counterbalance mechanism comprises a spring motor having a capstan for applying a substantially constant force to the tether.

12. The injury prevention device of claim 1, further comprising:an output selector comprising one or more electroadhesive clutches configured to selectively couple the injury prevention device to additional components.

13. The injury prevention device of claim 12, wherein the additional components comprise at least one of additional tethers and a gearbox.

14. The injury prevention device of 1, further comprising:a gearbox comprising a multi-diameter pulley, a floating pulley, or a block-and-tackle mechanism that reduces tether travel relative to internal component displacement.

15. The injury prevention device of claim 1, wherein the tether comprises:a Bowden cable having an inner cable connected to the output shaft and a cable housing configured to permit movement of the inner cable relative to the cable housing.

16. The injury prevention device of claim 1, further comprising:a rail connected to a helmet and configured to allow the tether to slide along a length of the rail.

17. The injury prevention device of claim 1, further comprising:a swivel mechanism connecting the tether to the rail.

18. The injury prevention device of claim 1, wherein adjacent clutch members share at least one conductive surface.

19. A method of preventing injury to a user comprising:sensing motion or acceleration of a body part of the user using one or more sensors to identify an event;if the event exceeds a threshold, applying a voltage to a first electroadhesive clutch to couple a tether to a housing preventing payout of the tether from a housing; or if the event does not exceed a threshold, applying voltage to a second electroadhesive clutch to couple the tether to a counterbalance mechanism.

20. A system for protecting a user from excessive motion, comprising:an injury prevention module including a plurality of electroadhesive clutches, a counterbalance mechanism, and a tether;a wearable element attached to an end of the tether;a sensor; anda controller configured to receive data from the sensor,wherein the controller actuates at least one electroadhesive clutch of the plurality of electroadhesive clutches to selectively restrict or permit movement of the wearable element.

21. The system of claim 21, wherein the wearable element is selected from a group consisting of a helmet, a cap, a collar, a flight harness, and a survival vest.

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