Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.

Patents

  1. Advanced Patent Search
Publication numberUS3631542 A
Publication typeGrant
Publication dateJan 4, 1972
Filing dateAug 11, 1969
Priority dateAug 11, 1969
Publication numberUS 3631542 A, US 3631542A, US-A-3631542, US3631542 A, US3631542A
InventorsPotter Allan G
Original AssigneeUniv Iowa Res Found
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Myoelectric brace
US 3631542 A
Abstract
A myoelectric brace consisting of a fixed wrist-hand splint portion having a movable finger support portion pivotally secured thereto which is operated by a hydraulic actuator. The actuator is hydraulically coupled to a pump which is driven by a battery powered, direct current motor. Three skin electrodes are positioned on the patient's arm and sense muscle potentials in the patient's arm when the patient tenses a muscle in the immediate area of the skin electrodes. The resulting myo-potentials are then amplified by a muscle potential amplifier and are transformed into a slowly varying control signal by a detector circuit and a filter circuit. The control signal enters a differential amplifier where it causes the motor to drive the hydraulic pump until a predetermined pressure is reached. Actuation of the hydraulic pump causes the hydraulic actuator to pivotally move the finger support towards the fixed splint portion. The motor stops when the differential amplifier receives a signal from the pressure transducer equal in amplitude to the control signal. This causes the differential amplifier output signal to go to zero. Relaxation of the patient's muscle causes the finger support to pivotally move away from the fixed splint portion.
Images(2)
Previous page
Next page
Description  (OCR text may contain errors)

United States Patent [72] Inventor Allan G. Potter Ames, Iowa [21] Appl. No. 848,919

[22] Filed Aug. 11, 1969 [45] Patented Jan. 4, 1972 [73] Assignee Iowa State University Research Foundation Ames, Iowa [54] MYOELECTRIC BRACE Myo-Electric Control of Powered Prostheses by A. H. Bottomley, The Journal of Bone & Joint Surgery, Vol. 47B, No.3,Aug.1965,pp.411-415,3-1.1

Gas-Powered Sources and Actuators for Prosthetic and Orthotic Devices" by J. R. Pearson, The Control of External Power in Upper-Extremity Rehabilitation, Nat. Academy of Sciences- Nat. Research Council, Wash., DC, 1966, pp. 196-197 (FIG. 5) copy in P.O. Scientific Library (RD756- N32C). 3-1.2

Myoelectric Control Systems" by W. Waring et al.,

Orthopedic & Prosthetic Appl. Journal, Vol. 21, No. 1, Mar. 1967, pp. 27-32. 3l.l

Myo-Electrically Controlled Electric Torque Motor for the Flexor Hinge Hand Splint by C. 'Irombley et al., Orthopedic & Prosthetic Appliance Journal, Vol. 21, No. 1, Mar. 1967, pp. 39-43. 3-1.1

Primary ExaminerRichard A. Gaudet Assistant Examiner-Ronald L. F rinks Attorney-Zarley, McKee & Thomte ABSTRACT: A myoelectric brace consisting of a fixed wristband splint portion having a movable finger support portion pivotally secured thereto which is operated by a hydraulic actuator. The actuator is hydraulically coupled to a pump which is driven by a battery powered, direct current motor. Three skin electrodes are positioned on the patients arm and sense muscle potentials in the patients arm when the patient tenses a muscle in the immediate area of the skin electrodes. The resulting myo-potentials are then amplified by a muscle potential amplifier and are transformed into a slowly varying control signal by a detector circuit and a filter circuit. The control signal enters a differential amplifier where it causes the motor to drive the hydraulic pump until a predetermined pressure is reached. Actuation of the hydraulic pump causes the hydraulic actuator to pivotally move the finger support towards the fixed splint portion. The motor stops when the differential amplifier receives a signal from the pressure transducer equal in amplitude to the control signal. This causes the differential amplifier output signal to go to zero. Relaxation of the patients muscle causes the finger support to pivotally move away from the fixed splint portion.

PATENTEDJAN 41912 3531.542

SHEET 1 [IF 2 Arrow/945 MYOELECTRIC BRACE Electrically powered orthotic devices or braces for quadraplegic patients are convenient because the electrical power is readily available and is easily stored in the batteries which drive the electric motors on wheel chairs used by such patients. The utilization of other types of energy storage techniques by these patients requires the handling of another source of energy and thus, another set of operating conditions which is highly undesirable. In order to utilize the electrical energy stored in the wheel chair batteries to effectively power orthotic devices, one must optimize several conflicting requirements. First, both the weight and size of the bracemounted actuator must be small. Second, the response and control of the limb brace when driven by the actuator must be normal. Third, minimum size, weight, and power consumption is desired for the complete device.

Therefore, it is a principal object of this invention to pro vide a myoelectric brace for quadraplegic patients.

A further object of this invention is to provide a myoelectric brace which is powered by a unique hydraulic system driven by a direct current battery operated motor.

A further object of this invention is to provide a myoelectric brace which is light weight.

A further object of this invention is to provide a myoelectric brace which has a minimum size and consumes a minimum of power.

A further object of this invention is to provide a myoelectric brace which is operated by the muscle potentials in the patients arm.

A further object of this invention is to provide a myoelectric brace wherein muscle potentials are sensed by surface electrodes and are used to control finger position and tension in a proportional manner.

A further object of this invention is to provide a method of actuating a myoelectric brace.

A further object of this invention is to provide a myoelectric brace which is economical of manufacture, durable in use and refined in appearance.

These and other objects will be apparent to those skilled in the art.

This invention consists in the construction, arrangements, and combination of the various parts of the device, whereby the objects contemplated are attained as hereinafter more fully set forth, specifically pointed out in the claims, and illustrated in the accompanying drawings in which:

FIG. I is a side elevational view of the brace mounted on the patients arm;

FIG. 2 is a top view of the brace as seen along lines 22 of FIG. I;

FIG. 3 is a longitudinal sectional view of the hydraulic actuator as seen along lines 3-3 of FIG. 1;

FIG. 4 is a fragmentary longitudinal sectional view of the hydraulic pump as seen along lines 4-4 of FIG. 1;

FIG. 5 is a block diagram of the electrical circuitry of this invention; and

FIG. 6 is a schematic view of the electrical circuitry of this invention.

The numeral 10 generally designates a fixed wrist-hand splint of this invention which is adapted to be secured to the patients lower arm, wrist and hand. Splint 10 includes a splint portion 12 which is secured to the patients arm 14 by a strap 16 extending therearound and selectively closed by a Velcro fastener means 18 (FIG. I). The upper end of splint portion 20 is pivotally connected to the lower end of splint portion 12 by a pin 22. Thumb support 24 extends downwardly from one end of splint portion 20 and is adapted to have the patient's thumb received therein (FIG. I). A curved support 26 is pivotally secured at its upper end to splint portion 20 by a pin 28 and has spaced-apart, finger supports 30 and 32 extending laterally therefrom. As seen in FIG. I, finger support 30 is adapted to have the patients fingers extending therethrough while finger support 32 is adapted to extend over the patient's fingers. An arcuate hand support 34 is secured to splint portion 20 and extends laterally therefrom adapted to cup or support the underside of the patients hand. Strap 36 extends around the patients hand to firmly maintain the device thereon.

A hydraulic actuator 38 is secured to splint portion 20 by bracket 40 and has a push rod 42 slidably extending therefrom which is pivotally secured by a pin 44 to one ofthe adjustment holes 46 formed in ear 48 which extends from the rearward end of support 26. Thus, extension of push rod 42 from the hydraulic actuator 38 causes support 26 to pivot towards thumb support 24. Conversely, the withdrawal of push rod 42 into the actuator 38 causes support 26 to pivot away from the thumb support 24.

Hydraulic actuator 38 includes a piston head portion 50 secured to cylinder housing 52 by head screws 54. A bellowfram 56 is positioned between piston head portion SI) and cylinder housing 52 as seen in FIG. 3. A U-shaped piston 58 is secured to bellowfram 56 by a piston cap screw 60 extending through piston cap 62, bellowfram 56 and into piston 58.

Push rod 42 is secured to piston 58 and extends through spaced apart ball bushings 64 and 66 to reduce friction. A helical compression spring 68 embraces push rod 42 between piston 58 and support 70 and yieldably resists the extension of push rod 42 from housing 52. Nipple 72 extends from piston head portion 50 and is adapted to have a fluid line 74 connected thereto to place the fluid chamber 76 in actuator 38 in communication with pump 78. Pump 78 includes a hollow piston head 80 having a nipple 82 extending therefrom adapted to receive the fluid line 74 thereon. Pump 78 includes a fluid chamber 84 having a pressure transducer 86 extending thereinto. Pressure transducer 86 is provided with an electrical lead 88 which extends to a differential amplifier which will be discussed hereinafter.

A bellowfram 90 is positioned between piston head 80 and cylinder housing 92 by means of cap screws 94. A U-shaped piston 96 is secured to the center of bellowfram 90 by cap screws 98 extending through cap 100, bellowfram 90 and into piston 96.

The other end of piston 96 has an end plate 104 secured thereto which bears against the ball bearing screw nut I02 which runs in a groove of a grooved helical screw I16. Screw 116 is secured to the drive shaft I05 which rotatably extends from a battery operated, direct current motor 106. The numeral 108 refers to a coupling housing positioned between motor I06 and housing 92 and maintained therebetween by screws 110. An oldham coupling 120 connects motor 106 to screw 116.

Energization of the motor 106 causes power shaft to rotate ball bearing screw 116. The rotation of screw I16 causes screw nut 102 to be moved along the groove of the screw I16 to cause spring I18 to drive piston 96 to the right as viewed in FIG. 4. Movement of piston 96 to the right causes the fluid in chamber 84 to be forced therefrom, through line 74 and into the fluid compartment of actuator 38. The fluid entering fluid compartment 76 in actuator 38 causes piston 58 to be moved to the left, as viewed in FIG. 3, which causes push rod 42 to be extended from the actuator 38 which in turn causes support 26, and hence the patients fingers, to be moved towards the thumb support 24.

The numerals I12, I14 and 116 refer to the skin electrodes which are placed adjacent the skin surface of the patients arm as indicated in FIG. I and maintained thereon by suitable means such as tape or the like. The electrodes are connected to a muscle potential amplifier generally referred to by the reference numeral 118 in FIGS. 5 and 6. If the patient desires to close his fingers, he tenses a muscle located near the skin surface electrodes. The resulting muscle potentials are then amplified by the muscle potential amplifier 118. This amplifier FIG. 6, consists ofa pair of operational amplifiers in a unity gain to common mode type circuit followed by a differential amplifier circuit, a parallel T" rejection filter circuit, and a Darlington amplifier circuit. The amplified myopotentials are then put into a detector circuit 120, consisting of a Schmidt trigger circuit followed by a low-pass filter circuit. This detector circuit transforms the amplified muscle potentials into a slowly varying control signal whose amplitude is related to the muscle tension causing it. if the output of the differential amplificr T24 is sufficiently large the motor control circuit 126 causes the motor 106 to drive the hydraulic pump 78 until a pressure related to the desired finger position plus tension is reached. The motor control circuit contains two identical control circuits consisting of a relaxation oscillator circuit which drives a hybrid timing circuit and a transistor bridge circuit. In this way both clockwise and counterclockwise rotation can be obtained depending upon which control circuit drives the transistor bridge circuit. The motor W6 stops when the signal from the pressure transducer 86 causes the differential amplifier B24 output signal to go below a set threshold level. If the patient wishes to open his fingers, he simply relaxes and the signal from the pressure transducer 86 causes the motor 106 to reduce the pressure so that the brace is driven to its zero muscle voltage position by the spring 68 contained in the actuator 33.

In summary, it can be seen that the myoelectric brace is driven by muscle potentials. The muscle potentials are created by tensing or contracting of the muscle which causes polarization of the muscle. The electrodes on the skin detect the E.M.G. differential and relays the same to the circuitry illustratcd in the drawings. The pump 78 and actuator 38 are especially designed to reduce friction through the use of the ball bushings 64 and 66 and through the use of the foldable bellowfram incorporated therein.

A brace has been provided which is lightweight and which requires a minimum of power to be consumed during the operation thereof. The size of the brace is relatively small and is conveniently secured to the patients arm. Finger position and lietlSlOtt is controlled in a proportional manner due to the muscle potentials being sensed by the surface electrodes and the relationship of the pressure transducer to the motor control circuit,

Thus it can be seen that the device accomplishes at least all ofits stated objectivesv lclaim:

l. in a myoelectric brace, comprising,

a splint means adapted to be secured to a person's arm and having a fixed wrist-hand splint portion and a movable finger support means pivotally connected thereto,

a hydraulic actuator means mounted on said fixed wristband splint portion and being connected to said movable finger support means to cause said finger support means to be moved with respect to said fixed splint portion,

a hydraulic pump means fluidly connected to said actuator means adapted to cause said actuator means to move said finger support means,

a motor means for operating said pump means,

an electrode means adapted to be placed on the wearer's skin surface adjacent a muscle capable of being tensed by the wearer,

a circuit means connected to said electrode means adapted to sense the myopotentials created by the tensing of said muscle and to transform the potentials into a control signal whereby said electric motor, said pump and said actuator will be operated so that said finger support means will be moved towards said fixed splint means, and

said pump means including a hollow piston head housing having a fluid compartment provided therein, said fluid compartment being in fluid communication with said actuator means, a cylinder housing connected to said piston head housing, a bellowfram between said piston head housing and said cylinder housing, a piston means in said cylinder housing connected to said bellowfram for movement therewith, a ball bearing screw rotatably mounted in said cylinder housing, a screw nut operatively connected to said piston means in engagement with said screw whereby rotation of said screw will cause said piston and said bellowfram to be moved, said motor having a drive shaft connected to said screw. I 2. The brace of claim 1 wherein a pressure transducer is in communication with said fluid compartment in said piston head housing, said pressure transducer being electrically connected to said circuit means to stop said motor when a predetermined pressure is reached in said fluid compartment.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
SU118581A * Title not available
Non-Patent Citations
Reference
1 * Gas Powered Sources and Actuators for Prosthetic and Orthotic Devices by J. R. Pearson, The Control of External Power in Upper Extremity Rehabilitation, Nat. Academy of Sciences Nat. Research Council, Wash., D.C., 1966, pp. 196 197 (FIG. 5)
2 * Myo Electric Control of Powered Prostheses by A. H. Bottomley, The Journal of Bone & Joint Surgery, Vol. 47B, No. 3, Aug. 1965, pp. 411 415
3 * Myo Electrically Controlled Electric Torque Motor for the Flexor Hinge Hand Splint by C. Trombley et al., Orthopedic & Prosthetic Appliance Journal, Vol. 21, No. 1, Mar. 1967, pp. 39 43
4 * Myoelectric Control Systems by W. Waring et al., Orthopedic & Prosthetic Appl. Journal, Vol. 21, No. 1, Mar. 1967, pp. 27 32
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3735425 *Feb 10, 1971May 29, 1973Us Of America The Secretary OfMyoelectrically controlled prothesis
US4016607 *Jul 30, 1976Apr 12, 1977Eino PihlajaArtificial hand
US4259806 *Jun 20, 1980Apr 7, 1981Summit Licensing CompanyWalking toy
US4340371 *Mar 18, 1981Jul 20, 1982The United States Of America As Represented By The Secretary Of The Air ForceUpper and lower arm load simulator
US4575297 *Dec 22, 1982Mar 11, 1986Hans RichterAssembly robot
US4679548 *Jan 25, 1985Jul 14, 1987Compagnie Generale De Material OrthopediqueRe-education apparatus for the articulated segments of the hand
US4724827 *Apr 19, 1985Feb 16, 1988Schenck Robert RFor tractioning a fractured bone and exercizing a joint proximal
US4782825 *May 21, 1987Nov 8, 1988Robert LonardoCombination arm splint and finger support means
US4792338 *Oct 15, 1986Dec 20, 1988Centri Gummifabrik AbArtificial hand
US4875469 *Jun 13, 1988Oct 24, 1989Innovative Medical Engineering, Inc.Continuous passive motion devices and methods
US5103811 *Jul 9, 1990Apr 14, 1992Crupi Jr Theodore PBody part or joint brace
US5147285 *Aug 1, 1991Sep 15, 1992Buxton Aldene HMovable thumb brace
US5222986 *Jan 27, 1992Jun 29, 1993Wright Donald MHand prosthesis for grasping large and small objects
US5252102 *Aug 5, 1992Oct 12, 1993Electrobionics CorporationPortable
US5376091 *Apr 11, 1994Dec 27, 1994Smith & Nephew Richards, Inc.Dynamic finger support
US5458560 *Sep 3, 1993Oct 17, 1995Jace Systems, Inc.Continuous passive motion device for a wrist
US5549709 *Jul 26, 1995Aug 27, 1996Caspers; Carl A.Hypobarically-Controlled artificial limb for amputees
US5620410 *Oct 3, 1995Apr 15, 1997Jace Systems, Inc.Continuous passive motion device for a wrist
US5653680 *Aug 10, 1995Aug 5, 1997Cruz; Mark K.Active wrist brace
US5683351 *Sep 27, 1994Nov 4, 1997Jace Systems, Inc.Continuous passive motion device for a hand
US5707345 *Aug 30, 1993Jan 13, 1998Para Tech Industries, Inc.Method for treating carpal tunnel syndrome
US5735906 *Jun 11, 1996Apr 7, 1998Caspers; Carl A.Hypobarically-controlled artificial limb with detents for amputees
US5800561 *May 15, 1996Sep 1, 1998Massachusetts Institute Of TechnologyPower-assisted upper extremity orthosis
US5904722 *Jun 2, 1997May 18, 1999Caspers; Carl A.Hypobarically-controlled, double-socket artificial limb with mechanical interlock
US6080123 *Sep 14, 1998Jun 27, 2000Pansiera; Timothy ThomasOrthotic joint with radial hydraulic force transfer
US6179799Feb 1, 1999Jan 30, 2001Robert E. DoranOrthosis for supination and pronation of the wrist
US6508842Jan 27, 2000Jan 21, 2003Barbara J. CaspersSocket liner for artificial limb
US6554868Mar 23, 2000Apr 29, 2003Carl A. CaspersVacuum pump and shock absorber for artificial limb
US6645253Feb 21, 2001Nov 11, 2003Carl A. CaspersVacuum pump and shock absorber for artificial limb
US6689074 *Feb 21, 2001Feb 10, 2004Seiko Epson CorporationWearable muscular-force supplementing device
US6726726Feb 16, 2001Apr 27, 2004Otto Bock Healthcare LpVacuum apparatus and method for managing residual limb volume in an artificial limb
US6761742Jan 29, 2002Jul 13, 2004Otto Bock Healthcare LpVacuum pump and shock absorber for artificial limb
US6926742Mar 4, 2002Aug 9, 2005Otto Bock Healthcare LpPlate/socket attachment for artificial limb vacuum pump
US6966882 *Nov 6, 2003Nov 22, 2005Tibion CorporationActive muscle assistance device and method
US6974484Jan 27, 2005Dec 13, 2005Otto Bock Healthcare LpOsmotic membrane and vacuum system for artificial limb
US7367958Apr 19, 2007May 6, 2008Massachusetts Institute Of TechnologyMethod of using powered orthotic device
US7396337Nov 21, 2003Jul 8, 2008Massachusetts Institute Of TechnologyPowered orthotic device
US7537573Sep 7, 2005May 26, 2009Tibion CorporationActive muscle assistance and resistance device and method
US7601130Aug 24, 2005Oct 13, 2009Saebo, Inc.Dynamic hand splint
US7652386 *Apr 30, 2008Jan 26, 2010Bionic Power Inc.Method and apparatus for harvesting biomechanical energy
US7659636Apr 30, 2008Feb 9, 2010Bionic Power Inc.Methods and apparatus for harvesting biomechanical energy
US7670385May 9, 2007Mar 2, 2010Otto Bock Healthcare GmbhInternal socket and fitting system for a prosthesis
US7811189Jan 3, 2007Oct 12, 2010Tibion CorporationDeflector assembly
US7892194Dec 12, 2005Feb 22, 2011Saebo, Inc.Dynamic hand splints
US7922775May 23, 2003Apr 12, 2011Otto Bock Healthcare LpPulsating pressure chamber and method for fluid management
US8016780 *Jan 2, 2009Sep 13, 2011George SicklesOrthopedic brace
US8052629Feb 6, 2009Nov 8, 2011Tibion CorporationMulti-fit orthotic and mobility assistance apparatus
US8058823Aug 14, 2008Nov 15, 2011Tibion CorporationActuator system with a multi-motor assembly for extending and flexing a joint
US8070702Oct 14, 2008Dec 6, 2011Saebo, Inc.Splint assembly for positioning of the hand
US8274244Jan 30, 2009Sep 25, 2012Tibion CorporationActuator system and method for extending a joint
US8299634Aug 10, 2006Oct 30, 2012Bionic Power Inc.Methods and apparatus for harvesting biomechanical energy
US8328743Sep 3, 2009Dec 11, 2012Saebo, Inc.Dynamic hand splint
US8328744Feb 21, 2011Dec 11, 2012Saebo, Inc.Dynamic hand splints
US8353854Oct 31, 2007Jan 15, 2013Tibion CorporationMethod and devices for moving a body joint
US8487456Oct 10, 2012Jul 16, 2013Bionic Power Inc.Methods and apparatus for harvesting biomechanical energy
US8496715Apr 22, 2008Jul 30, 2013Otto Bock Healthcare LpPneumatic connections for prosthetic socket
US8585620Mar 18, 2009Nov 19, 2013Myomo, Inc.Powered orthotic device and method of using same
US8591599 *Jan 7, 2011Nov 26, 2013Infinite Biomedical Technologies, LlcElectrode assemblies for detecting muscle signals in a prosthetic liner
US8639455Feb 9, 2010Jan 28, 2014Alterg, Inc.Foot pad device and method of obtaining weight data
US8679040Nov 7, 2011Mar 25, 2014Alterg, Inc.Intention-based therapy device and method
US8736087Sep 1, 2011May 27, 2014Bionic Power Inc.Methods and apparatus for control of biomechanical energy harvesting
US8758449Apr 22, 2011Jun 24, 2014Otto Bock Healthcare LpSocket liner for artificial limb
US8771210Oct 14, 2011Jul 8, 2014Alterg, Inc.Multi-fit orthotic and mobility assistance apparatus
US8784348Dec 5, 2011Jul 22, 2014Saebo, Inc.Splint assembly for positioning of the hand
US20110004322 *Sep 14, 2010Jan 6, 2011University Of TsukubaWearable action-assist device and control program
US20110282253 *Sep 21, 2010Nov 17, 2011Carlo MenonWrist exoskeleton
US20120101596 *Jun 11, 2010Apr 26, 2012Otto Bock Healthcare Products GmbhMethod for setting up a control and technical orthopedic device
USRE33182 *Mar 14, 1989Mar 20, 1990Compagnie Generale De Materiel OrthopediqueRe-education apparatus for the articulated segments of the hand
CN100427047CJun 14, 2006Oct 22, 2008吉林大学Automatic medical constant-force small splint
EP0650708A1 *Oct 29, 1993May 3, 1995Carl Anthony CaspersProsthetic liner and method of making the liner with a prosthesis socket
EP1010407A1 *Oct 29, 1993Jun 21, 2000Carl Anthony CaspersProsthetic liner and method of making the liner with a prosthetic socket
WO1983002249A1 *Dec 22, 1982Jul 7, 1983Hans RichterMounting robot
WO1987001082A1 *Jul 30, 1986Feb 26, 1987Martin WerderCross-country vehicle
WO2004019834A1 *Aug 19, 2003Mar 11, 2004Univ Berlin TechDevice for influencing movement with a parallel mechanism
WO2006072068A2 *Dec 30, 2005Jul 6, 2006John Fletcher FarrellDynamic splint assembly
WO2008036746A2 *Sep 19, 2007Mar 27, 2008Myomo IncPowered orthotic device
WO2010117065A1 *Apr 9, 2010Oct 14, 2010University Of TsukubaWearable motion assist device
Classifications
U.S. Classification623/25, 602/21, 623/26, 601/40
International ClassificationB25J9/00, A61F5/01, A61F2/72, A61F2/50, A61F2/70
Cooperative ClassificationA61F2002/701, A61F2002/748, B25J9/0006, A61F2/72, A61F2002/741, A61F2002/5075, A61F2002/745, A61F5/013
European ClassificationB25J9/00E, A61F2/72, A61F5/01D7