Ulllted States Patent [19]
`Stewart et al.
`
`US005978972A
`[11] Patent Number:
`[45] Date of Patent:
`
`5,978,972
`*Nov. 9, 1999
`
`[54] HELMET SYSTEM INCLUDING AT LEAST
`THREE ACCELEROMETERS AND MASS
`MEMORY AND METHOD FOR RECORDING
`
`46-38389 11/1971 Japan .
`612349 6/1978 Russian Federation .
`1035523A 8/1983 Russian Federation .
`
`ACCELERATION DATA OF A HEAD
`
`[75] Inventors: Walter Stewart, Baltimore; Nicholas
`Jones, Monkton; wolfger Schneider,
`Columbia, all of Md
`
`[73] Assignee: Johns Hopkins University, Baltimore,
`Md‘
`Under 35 U.S.C. 154(b), the term of this
`patent shall be extended for 00 days.
`
`Notice:
`
`[ * ]
`
`[21] Appl. No.: 08/872,675
`
`[22]
`
`Filed:
`
`Jun‘ 11’ 1997
`
`Related US. Application Data
`Provisional application No. 60/020,271, Jun. 14, 1996.
`
`[60]
`
`Int. Cl.6 ...................................................... .. A42B 3/04
`[51]
`[52] [15- Cl- ---------------------- -- 2/422; 2/425; 2/906; 73/491;
`340/669
`[58] Field of Search .............................. .. 2/422, 425, 906;
`340/669; 455/100; 73/488, 489, 491, 492,
`514.01, 514.02, 514.35
`
`[56]
`
`_
`References Clted
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`
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`'
`
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`
`Primary Examiner—Peter Nerbun
`Art
`A t
`F' —P'llb M d' &S t LLP
`Omey’ gen’ Or um I S my a lson
`u m
`[57]
`ABSTRACT
`
`A System designed to measure and record in real time data
`relating to translational and angular acceleration of an
`individual’s head during normal sporting activity. One
`embodiment of the device includes at least three orthogonal
`accelerometers mounted Within a sports helmet together
`With means for recording, in real-time, the data output from
`the accelerometers. The data is either recorded on a memory
`card or other mass memory means installed in the helmet, or
`is transmitted to a nearby receiver for reception and storage
`on a computer s hard drive or other conventional mass
`storage device. The device provides real-time storage of
`translational and angular acceleration data over a length of
`time such that cumulative exposure effects and thus limits
`can be established for the individual’s further or future
`participation in the sport. The data also alloWs detection of
`the precise motions of the head Which precede the occur
`rence of a severe head injury.
`
`700591
`
`1/1966 Italy.
`
`20 Claims, 7 Drawing Sheets
`
`53
`
`52
`
`42
`
`SERlAL
`PERlPHERAL
`INTERFACE
`
`SERlAL
`CONTROL
`\IF
`
`10
`
`E“
`
`DNA
`STORAGE
`
`POWER
`SUPFLV
`
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`
`

`

`US. PATENT DOCUMENTS
`
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`
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`
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`
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`
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`
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`
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`
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`
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`
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`
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`
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`
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`
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`
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`
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`
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`
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`
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`
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`
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`
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`
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`
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`
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`
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`
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`
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`
`5,978,972
`Page 2
`
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`. 2/422 X
`5,631,427
`5/1997 Bridges ............................... .. 73/491 X
`
`OTHER PUBLICATIONS
`
`F. A. Pintar et al, “Experimental Production of Head—Neck
`Injuries Under Dynamic Forces”, Head and Neck Injuries in
`Sports, ASTM STP 1229, American Society for Testing and
`Materials, Philadelphia, 1994, pp. 203—211.
`W. H. MuZZy III et al, “Comparison of Kinematic Param
`eters Between Hybrid II and Neck System With Human
`Volunteers for —Gx Acceleration Pro?les”, Naval Aerospace
`Medical Research Laboratory Detachment, 20th Stapp Car
`Crash Conference, pp. 43—74.
`D.C. Schneider et al, “Impact Studies of Facial Bones and
`Skull”, (720965) Impact Studies, pp. 186—203.
`Alan M. Nahum et al, “Impact Tolerance of the Skull and
`Face”, (680785), Proceedings of Twlfth Stapp Car Crash
`Conference, pp. 302—316, (Oct. 22—23).
`Gerald W. Nyquist et al, “Facial Impact Tolerance and
`Response”, (861896) Thirtieth Stapp Car Crash, pp.
`379—400, Oct. 1986.
`C. Got et al, “Results of Experimental Head Impacts on
`Cadavers: The Various Data Obtained and Their Relations to
`Some Measured Physical Parameters”, (780887) pp. 57—99,
`1978 Society of Automotive Engineers, Inc.
`Channing L. Ewing et al, “Dynamic Response of the Head
`and Neck of the Living Human to —Gx Impact Acceleration”,
`(680792), Proceedings of Twelfth Stapp Car Crash Confer
`ence, pp. 424—439, 1968.
`C. L. Ewing et al, “The Effect of the Initial Position of the
`Head and Neck on the Dynamic Response of the Human
`Head and Neck to —Gx Impact Acceleration”, 20th Stapp Car
`Crash Conference, pp. 487—512, 1975.
`C. L. Ewing et al, “Living Human Dynamic Response to
`G—II Accelerations Measured on the Head and Nec ”,
`(690817) 13th Stapp Car Crash Conference, pp. 400—415,
`1969.
`C. L. Ewing et al, “Torque Versus Angular Displacement
`Response to Human Head to —Gx Impact Acceleration”,
`(730976) Response to Human Head.
`N. R. Ordway et al, “The Effect of Head Position on the
`Analysis of Cervical Motion”, Head and Neck Injuries in
`Sports, ASTM STP 1229, Earl F. Hoerner, Ed. American
`Society for the Testing and Materials, Philadelphia, 1994,
`pp. 212—220.
`
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`
`

`

`5,978,972
`Page 3
`
`L. W. Schneider et al, “Prediction of Head/Neck Dynamic
`Response of Selected Military Subjects to —Gx Accelera
`tion”, Aviation, Space and Environmental Medicine, Jan.
`1978, pp. 211—223.
`W. H. Zangemeister et al, “Cerebral Potentials Evoked by
`Fast Head Accelerations”, Neurological University Clinic
`Hamburg, Hamburg, FRG, Neurological Research, Sep.
`1990, vol. 12, pp. 137—146.
`C. S. Tien et al, “Numerical Advances in Gross—Motion
`Simulations of Head/Neck Dynamics”, Journal of Biome
`chanical Engineering, May 1987, vol. 109, pp. 163—168.
`J. W. Melvin et al, “Angular Acceleration Measurement
`Techniques for Head Impact”, Biomedical Science Dept.,
`General Motors Research Laboratories, Warren, MI, pp.
`31—37.
`Robert W. Mann et al, “Gait Analysis—Precise, Rapid
`Automatic, 3—D Position and Orientation Kinematics and
`Dynamics”, NeWman Laboratory.
`A. J. Padgaonkar et al, Measurement of Angular Accelera
`tion of a Rigid Body Using Linear Accelerometers, Biome
`chanics Research Center, Transactions of the ASME, Sep.
`1975, pp. 552—556.
`Y. King Liu, “Measurement of Angular Acceleration of a
`Rigid Body Using Linear Accelerometers”, Journal of
`Applied Mechanics, Jun. 1976, pp. 377—378.
`Werner Goldsmith et al, “Numerical Evaluation of the
`Three—Dimensional Response of a Human Head—Neck
`Model to Dynamic Loading”, (840861), Dept. of Mechani
`cal Engineering, University of California, Berkeley, pp.
`19—95.
`
`A.H.S. Holboum, “Mechanics of Head Injuries”, Lewis B.
`Flinn Library, DelaWare Academy of Medicine, Oct. 9,
`1943, pp. 438—441.
`
`L. Schmid et al, “Experience With Headgear in Boxing”,
`Sports Medicine, 1968, pp. 171—176.
`
`J. Johnson, “Peak Accelerations of the Head Experienced in
`Boxing”, Medical and Biological Engineering, May 1975,
`pp. 396—404.
`
`F. Unterhamscheidt, “The Historical and Medical Aspects—
`Boxing”, American Society for Testing and Materials, Phila
`delphia, 1994, pp. 257—286.
`
`D. F. Meaney et al, “Diffuse Axonal Injury in the Miniature
`Pig: Biomechanical Development and Injury Threshold”,
`AMD, vol. 169/Med, vol. 25, CrashWorthiness and Occu
`pant Protection in Transportation Systems ASME 1993, pp.
`169—175.
`
`F. Unterhamscheidt, “30 Plus Years of Head and Neck
`Injuries—Primate and Human Models’ Responses to Energy
`Load and Forces”, American Society for Testing Materials,
`Philadelphia, 1994, pp. 177—257.
`
`David C. Viano et al, Measurement of Head Dynamics and
`Facial Contact Forces in the Hybrid III Dummy, General
`Motors Research Labs. Biomedical.
`
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`

`

`U.S. Patent
`
`Nov. 9, 1999
`
`Sheet 1 0f 7
`
`5,978,972
`
`11
`
`\ \
`”
`
`/46
`
`ND
`CONVERTER
`
`CH0
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`CH1>
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`53
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`SERIAL
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`INTERFACE
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`42
`52
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`SERIAL
`CONTROL < e PC
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`44
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`STORAGE
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`I/F
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`
`FIG. 1
`
`54
`/
`
`POWER
`SUPPLY
`
`IPR2018-00564
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`
`

`

`U.S. Patent
`
`Nov. 9, 1999
`
`Sheet 2 0f 7
`
`FlG. 2A
`
`IPR2018-00564
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`
`

`

`U.S. Patent
`
`Nov. 9, 1999
`
`Sheet 3 of7
`
`5,978,972
`
`12
`
`:
`
`“ ‘Ir-5
`L4
`Lri
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`40
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`FIG. 2B
`
`IPR2018-00564
`Garmin EX1004 Page 6
`
`

`

`U.S. Patent
`
`N0v.9,1999
`
`Sheet 4 of7
`
`5,978,972
`
`ANGULAR VELOCITY
`DIRECTION
`OF
`MOTION
`
`* Y
`
`T
`
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`\
`
`,
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`
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`
`IPR2018-00564
`Garmin EX1004 Page 7
`
`

`

`U.S. Patent
`
`Nov. 9, 1999
`
`Sheet 5 of7
`
`5,978,972
`
`IPR2018-00564
`Garmin EX1004 Page 8
`
`

`

`U.S. Patent
`
`Nov. 9, 1999
`
`Sheet 6 of7
`
`5,978,972
`
`FIG. 4C
`
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`

`

`U.S. Patent
`
`Nov. 9, 1999
`
`Sheet 7 of7
`
`5,978,972
`
`FIG. 5
`
`IPR2018-00564
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`
`

`

`1
`HELMET SYSTEM INCLUDING AT LEAST
`THREE ACCELEROMETERS AND MASS
`MEMORY AND METHOD FOR RECORDING
`IN REAL-TIME ORTHOGONAL
`ACCELERATION DATA OF A HEAD
`
`This application claims the bene?t of the Provisional
`Appln. No. 60/020,271 ?led Jun. 14, 1996. +gi
`
`GOVERNMENT RIGHTS
`
`The invention described herein Was made in the course of
`Work under grant number 5R01NS26450 from the National
`Institute of Health. The US. Government may retain certain
`rights in this invention.
`
`BACKGROUND
`
`1. Field of the Invention
`The present invention relates to real-time recording of the
`translational and angular acceleration of a head and, in
`particular a human head and, in a most preferred
`implementation, the head of a living human subject in
`normal activity.
`More particularly, it relates to a helmet-based system
`Which is typically Worn While playing a sport such as boxing
`or football, and to the method of recording and storing data
`relating to translational and angular accelerations of the
`person’s head due to impact forces acting thereon.
`2. Background of Related Art
`Translational movement relates to the motion of a rigid
`body in such a Way that any line Which is imagined rigidly
`attached to the body remains parallel to its original position.
`Translational acceleration is the time rate of change of the
`velocity of the translational movement. Angular acceleration
`(also called rotational acceleration) is shoWn in FIG. 3. As
`point p moves on a circular path With radius r through
`angular displacement G), angular velocity is the rate of
`change of 6) With respect to time. Angular acceleration (x2 is
`the rate of change of angular velocity. The tangential com
`ponent of translational motion T shoWn in FIG. 3 is actually
`measured. Normal acceleration (Which is a form of transla
`tional acceleration) relates to the acceleration toWard the
`center of the circular motion.
`Little is knoWn about hoW a living human head acceler
`ates in translational and angular directions in response to
`forces, and even less about the correspondence betWeen
`speci?c forces and injury, particularly With respect to inju
`ries caused by repeated exposure to impact forces of a loWer
`level. Almost all of What is knoWn is derived from animal
`studies, studies of cadavers under speci?c directional and
`predictable forces (i.e. a head-on collision test), and from
`crash a dummies or other simplistic mechanical models. The
`conventional simplistic application of knoWn forces and/or
`measurement of forces applied to animals, cadavers, and
`crash dummies limit our knoWledge of a relationship
`betWeen forces applied to a living human head and resultant
`injury thereto.
`Some conventional devices have employed modeled test
`ing approaches Which do not relate to devices Which can be
`Worn by living human beings.
`When studying impact With dummies, they are typically
`secured to sleds With a knoWn acceleration and impact
`velocity. The dummy head then impacts With a target, and
`the peak accelerations experienced by the head are recorded.
`Impact studies using cadavers are performed for determining
`the impact forces and pressures Which cause skull fractures.
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`55
`
`60
`
`65
`
`5,978,972
`
`2
`For instance, US. Pat. No. 4,873,867 to McPherson et al.
`and US. Pat. No. 4,691,556 to Mellander et al. disclose the
`use of accelerometers mounted Within cavities formed in the
`head of a crash dummy. Viano et al. “Measurement of Head
`Dynamics and Facial Contact Forces in the Hybrid III
`Dummy” and Shea et al. “Computing Body Segment Tra
`jectories in the Hybrid III Dummy Using Linear Acceler
`ometer Data” disclose the placement of betWeen seven and
`nine accelerometers inside a cavity formed in the head of a
`dummy. Pintar et al. “Experimental Production of Head
`Neck Injuries Under Dynamic Forces” discloses removal of
`the top of a cadavers head and placement of accelerometers
`therein. Got et al. “Results of Experimental Head Impacts
`On Cadavers: The Various Data Obtained and Their Rela
`tions to Some Measured Physical Parameters” disclose the
`use of high speed photography and three accelerometers
`screWed into different positions in a cadavers skull, depend
`ing on the impact test to be performed. Nahum et al. “Impact
`Tolerance of the Skull and Face” disclose testing of a human
`skull using a single uniaxial accelerometer placed opposite
`a predetermined point of impact.
`Other conventional devices have measured the accelera
`tion of a living human head, but these devices have mea
`sured a speci?c, usually single axis of acceleration Which
`Was knoWn beforehand With a single accelerometer placed
`accordingly, and/or relate to devices Which are not Worn in
`everyday practice of sports. Moreover, because these
`devices measure the limits of living human response to
`predetermined forces and the results thereof, they require
`many factors of safety.
`For instance, Schmid et al. “From the Practice, Experi
`ence With Headgear in Boxing” discloses the use of a
`transistor apparatus With crystal gauges and a loop
`oscillograph to measure skull accelerations. TWo crystal
`gauges Were fastened to the head by bandages, one on the
`occipital bone and the other on the temporal bone.
`The device measured a predetermined force from a pre
`determined direction. Johnson et al. “Peak Accelerations of
`the Head Experienced in Boxing” discloses the use of one
`pieZoelectric accelerometer held on by a scuba diving hel
`met. MuZZy III, et al. “Comparison of Kinematic Parameters
`BetWeen Hybrid II Head and Neck System With Human
`Volunteers for -Gx Acceleration Pro?les” discloses the use of
`six accelerometers held Within a subject’s mouth. Similarly,
`US. Pat. No. 4,461,553 to Doerr et al. discloses the use of
`accelerometers in a mouthpiece. EWing et al. “Dynamic
`Response of the Head and Neck of the Living Human to -Gx
`Impact Acceleration” discloses a cumbersome, vieW
`blocking device Wherein a biaxial accelerometer is held in
`the mouth, and another is strapped over the bregma, and
`these are measured together With a photo-technique to
`determine accelerations. This device measured forces from
`a predetermined single direction of force. The use of a rate
`gyroscope held in the mouth of the subject is disclosed by
`EWing et al. “Living Human Dynamic Response to -Gx
`Impact Acceleration II—Accelerations Measured on the
`Head and Neck”, and EWing et al. “Torque versus Angular
`Displacement Response of Human Head to -Gx Impact
`Acceleration”.
`Some conventional devices have required cumbersome
`and complex circuitry Which is hardWired betWeen the
`sensors and the computing device. These devices are
`impractical for use in actual sporting events.
`For instance, OrdWay et al. “The Effect of Head Position
`on the Analysis of Cervical Motion” discloses electromag
`netic sensors attached to the top of the head With a velcro
`
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`

`3
`strap. In this device, a ?xing vest Was Worn by the subject
`to exclude ?exion and extension of the thoracic spine from
`the measurements, and the digitizing system Was hardwired
`to a personal computer for data collection. US. Pat. No.
`3,788,647 to Evans discloses the temporary use of a sWing
`measurement system for analyzing test sWings of an ath
`lete’s arm, bat or club for ?tting of orthopedic devices.
`Models are less desirable than measurement of a living
`human head during performance of the actual sport because
`of the uniqueness of the human anatomy and thus the limited
`extent to Which the living human head can be modeled
`adequately With mechanical models or even cadavers.
`Moreover, modeling alone does not provide data as to the
`cause of an injury experienced by a speci?c individual.
`Non-living heads (i.e. cadavers) do not account for the
`application of muscle tension in the neck nor for muscular
`or pain reactions of the head. For instance, modeling the
`forces impacting on a persons head does not provide speci?c
`data as to an injury suffered by a particular individual, i.e.,
`data derived from models and cadavers does not provide the
`means to correspond actual human injuries to the speci?c
`accelerations Which may have caused the injury.
`Helmets are conventional devices. It has been knoWn to
`conduct drop tests of helmets using an accelerometer placed
`opposite the predetermined site of impact. For instance, see
`the drop tests performed on football helmets disclosed by
`US. Pat. No. 4,326,303 to Rappleyea, and Us. Pat. No.
`3,994,020 to Villari. HoWever, these tests are most often
`destructive tests and do not provide data for a speci?c person
`While Wearing the helmet for its intended use, e.g., during a
`football game. Moreover, these tests speci?cally tested hel
`mets themselves (not the resultant force to the head), and
`measured thresholds for Which the helmets Would crack or
`break, not the head.
`There are other devices that have been developed to
`measure head motions for a variety of other applications.
`These include: (1) In military applications, systems have
`been developed to monitor the orientation of a pilot’s head
`to assist in targeting. (2) In virtual reality systems, the
`motion of the head and other extremities is continuously
`monitored to provide feedback to the computer enabling
`updating of images, etc. But these applications are for
`helmets Which are extensively instrumented, must remain
`hardWired to the support infrastructure, typically use only
`one or tWo position detectors, and do not measure and record
`forceful bloWs to the head.
`For instance, U.S. Pat. No. 4,743,200 to Welch et al.
`discloses a ?ber optic helmet used for control of a display
`system. HoWever, this system not only requires complex
`circuitry and a permanent ?ber optic connection to large
`pieces of equipment, it is not used during performance of a
`sport, and the accelerometer is used to determine only the
`position of the head, not to determine translational and
`angular acceleration due to undetermined external forces.
`US. Pat. No. 4,769,629 to TigWell discloses the use of a
`tWo-position mercury sWitch in a motorcycle helmet to light
`a stop light When decelerating in the forWard direction only.
`Placement of a motion sensor on the head has been
`knoWn.
`For instance, US. Pat. No. 4,440,160 to Fischell et al.
`discloses the use of a single accelerometer in a headband for
`detecting Whether or not the head is accelerating beyond a
`threshold amount. US. Pat. No. 4,869,509 to Lee, U.S. Pat.
`No. 4,502,035 to Obenauf et al., and US. Pat. No. 4,560,166
`to Emerson all disclose a motion sensor mounted on a
`golfer’s cap to sense improper head movement during a golf
`
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`sWing. HoWever, long term exposure to continual forces can
`be as injurious to a head as can be a single hard bloW.
`Conventional devices do not measure and record transla
`tional and angular forces to a living human head over a
`period of time of exposure, particularly Where the exposure
`is of a loW level beloW that Which Would normally cause
`concern for injury. For instance, continual bloWs to a head
`during a boxing match or football game may not cause injury
`individually but in combination may prove lethal. Head
`injury in these sports can have signi?cant short and long
`term consequences Which can be made more severe if bloWs
`to the head continue (e.g., from continued play in the same
`game or in a subsequent game). Thus, conventional devices
`Which measure acceleration in a single direction, or from a
`single event, or only above a predetermined threshold, or in
`a Way Which does not permit use during performance of the
`actual sport do not provide the dynamics necessary to
`correlate exposure to forces to the injury caused by that
`exposure over a period of time.
`Injuries are not the only area of study Which are de?cient.
`In sports such as boxing Where the bout is scored With the
`number of punches of a certain force connecting to the head,
`scoring is made dif?cult by conventional observational
`techniques of scoring.
`
`SUMMARY OF THE INVENTION
`The Head Acceleration-monitoring Technology (HAT) is
`a portable system designed to measure and record accelera
`tion data in real time in both translational and angular
`directions of an individual’s head during normal activity.
`While developed speci?cally for the head, monitoring of
`other body parts, or the body in general is envisioned.
`HAT offers the opportunity to study head acceleration,
`human tolerance limits, the range and direction of accelera
`tions in humans in relation to morphological features (e.g.,
`neck circumference, head volume, neck length), and the
`relationship betWeen precise measures of head acceleration
`in translational and angular directions and acute conse
`quence to brain physiology and function. Moreover, it
`provides the ability to measure an individual’s cumulative
`exposure to translational and angular accelerations While
`alloWing unaffected performance of everyday sports and
`activities.
`The HAT is designed as a standard component of other
`Wise conventional sporting gear, in particular the helmet. It
`includes at least three orthogonally-placed accelerometers
`and means to record the output therefrom in real time. As
`many as three sets of three orthogonally-placed accelerom
`eters can be used to measure uniquely the translational,
`angular and normal components of acceleration of the head.
`In one embodiment, three orthogonally-placed accelerom
`eters are sufficient to provide some translational and angular
`acceleration information regarding the head by integration.
`The translational, angular and normal components of accel
`eration become more detailed (and thus separable) by the
`use of more accelerometers. At most, nine accelerometers
`are placed in the helmet so as to de?ne all angular and
`translational accelerations of the head.
`The data from the accelerometers are recorded in real time
`during performance of the sport. The data is either recorded
`on a memory card or other mass memory means installed in
`the helmet, or is transmitted to a nearby receiver for storage
`on a computer’s hard drive or other conventional mass
`storage device. The HAT provides real-time storage of data
`over a length of time such that cumulative exposure effects
`and thus limits can be established for further or future
`
`IPR2018-00564
`Garmin EX1004 Page 12
`
`

`

`5,978,972
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`5
`participation in the sport by the individual Wearing the
`helmet equipped With the present invention. The data also
`alloWs detection of the precise motions of the head Which
`precede the occurrence of a severe head injury. For this
`purpose HAT could be modi?ed to record in real-time
`detailed data only When the accelerations exceed a de?ned
`threshold. The data is recorded in real-time, but may be
`processed in either real-time as the data is recorded, or at a
`later time so as to integrate and otherWise determine the
`translational, angular and normal components of accelera
`tion of the sportsperson’s head.
`The present invention is applicable for use With other
`parts of the body. For instance, other applications could
`include the study of the acceleration of body parts in relation
`to each other (e.g., among pole vaulters, high jumpers, or
`gymnasts), or to understand factors affecting acceleration in
`sprinters and sWimmers (e.g., starting and turns). Because of
`its portability, small siZe, and convenient light-Weight, HAT
`can also be used to study the acceleration of the body parts
`of live animals. For example, the acceleration and decelera
`tion of birds in ?ight could be studied With a modi?ed
`version of HAT.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`The present invention Will be understood better With
`reference to the draWings, in Which:
`FIG. 1 is a block diagram of the ?rst embodiment of the
`present invention;
`FIG. 2(a) is a right side vieW of a ?rst embodiment of the
`present invention using three orthogonal accelerometers and
`a memory card installed inside a boxing helmet;
`FIG. 2(b) is a top vieW of the ?rst embodiment of the
`present invention;
`FIG. 3 is a diagram shoWing angular (rotational) velocity
`about a Z axis and normal acceleration;
`FIG. 4(a) is a schematic top vieW of the present invention
`shoWing the X axis, y axis, and rotational acceleration (XZ
`about the center of mass of the head;
`FIG. 4(b) is a right side vieW of the present invention
`shoWing the X axis, Z axis, and rotational acceleration (1.),
`about the center of mass of the head;
`FIG. 4(c) is a front vieW of the present invention shoWing
`the y axis, Z axis, and rotational acceleration (xx about the
`center of mass of the head; and
`FIG. 5 shoWs a top vieW of a second embodiment of the
`present invention using three pairs (six total) of parallel
`accelerometers in a sporting helmet.
`
`DESCRIPTION OF PRESENTLY PREFERRED
`EMBODIMENTS
`
`FIG. 1 shoWs a general block diagram of the electronic
`portion of a ?rst embodiment of the present invention
`installed inside a sports helmet. Aprocessor 52 controls data
`sampling and storage operations With respect to data from an
`A/D Converter 46 for storage in a Personal Computer
`Memory Control Interface Adapter (PCMCIA) card
`installed in a PCMCIA Interface 50. The device further
`includes program RAM and ROM 48, and a Serial Control
`Interface 42.
`FIGS. 2(a) and 2(b) shoW the ?rst embodiment of the
`present invention installed in an otherWise conventional
`boxing helmet While being Worn by a boxer. FIG. 2(a) is a
`right side vieW, While FIG. 2(b) is a top vieW shoWing the
`nose 40 of the boxer.
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`The speci?c type helmet 30 is any Which is convention
`ally used in the sport for Which the invention is being
`applied. For instance, in this embodiment, the helmet 30 is
`a boxing helmet. Other helmets Which the present invention
`is applicable to, but in no Way is limited to, are football
`helmets, lacrosse helmets, hockey helmets, bicycle helmets,
`and motorcycle helmets. The helmet might also be one Worn
`by epileptics or other patients in need of protection from
`injury to the head.
`An important goal in the design of the HAT Was that the
`translational, angular and normal accelerations experienced
`by the head be captured accurately and suf?ciently through
`optimal location of at least three accelerometers 10—12. It is
`found that a minimum of three orthogonal accelerometers
`10—12 are suf?cient to provide data Which corresponds
`directly to motion of the head in three dimensional space
`such that a correspondence betWeen translational and rota
`tional acceleration of the head and any resultant injury can
`be determined on a mass population Who practice the
`respective sport (e.g. boxing, football, bicycling, etc.).
`It Was also important that the electronic components used
`in the HAT be small enough to be contained inside the
`helmet Without signi?cant change to the structure and func
`tion of the conventional helmet. In this Way, the HAT is
`comfortable enough for the sports person to Wear in the
`relevant everyday sports activity Without hindering,
`inhibiting, or otherWise affecting the ability of the user to
`perform the sport.
`In the ?rst embodiment of the present invention, three
`accelerometers 10—12 are installed orthogonal to one
`another inside a boxing helmet 30. Although three acceler
`ometers 10—12 are considered to be minimum, as many as
`nine accelerometers can be used so as to uniquely resolve
`measurement of the translational, angular and normal com
`ponents of acceleration of the head.
`The three accelerometers 10—12 are capable of providing
`point estimates of head acceleration at the location of the
`accelerometers 10—12. HoWever, theoretically, six acceler
`ometers provide more detailed data suf?cient to resolve the
`head motions into three translational and three rotational
`accelerations about the center of mass of the head. The
`maximum number of nine accelerometers Would provide the
`ability to separate the tangential and normal components of
`acceleration.
`The three orthogonal accelerometers 10—12 of the present
`embodiment provide aggregated data relating to three trans
`lational directions and tWo angular accelerations, but not
`suf?cient information to separate translational and rotational
`components uniquely. Of course, any tWo translational
`accelerations and associated angular acceleration can be
`measured by the use of three suitably located and oriented
`accelerometers as disclosed by the present invention. The
`more accelerometers that are implemented, the more
`detailed the information provided Will be, and the opportu
`nity provided to resolv