Electronically controlled prosthetic system

A prosthetic joint system for users comprising a housing having an interior cavity, a center axis in said interior cavity, and an attachment means for fixedly connecting said housing to said user; an inner cylinder disposed in said housing interior cavity wherein said inner cylinder rotates around said center axis of said housing; an appendage attached to said inner cylinder; a sensor system attached to said appendage; and a dampening system, having a power source, in communication with said sensor system, said inner cylinder, and said housing for controlling dampening of the rotation of said inner cylinder around said center axis of said housing.

FIELD OF THE INVENTION

The present invention relates generally to an ankle and foot joint system. More particularly, the present invention is a new and improved prosthetic joint system which simulates natural human locomotion and human biomechanics through sensory feed back, time feedback, electronically controlled dampening joint assembly, and a microprocessor control system.

DESCRIPTION OF THE KNOWN PRIOR ART

As the study of human physiology and anatomy clearly demonstrates, the relative simple action of walking on an even flat surface involves numerous biomechanical complexities. A single step requires constant biofeedback such as continual analysis of proprioception, angulations, timing, and balanced muscular-skeletal functions. In the prior art, the prosthetic industry is continuously attempting to mimic natural human locomotion (NHL), performance and aesthetics.

The field of prosthetics, in general, has made enormous advances in improving amputee and congenitally deformed individuals' performance on multiple levels from general ambulation to competitive sports through improved technology and understanding of human biomechanics. Although, it is known in the art to manufacture ankle and foot prosthetic combinations that have generally increased performance and appearance, the prior art is still deficient on numerous levels as will be discussed in greater detail below.

Many prosthetic feet are optimized for a small or limited range of activities. Typically, models aligned for such activities as daily walking are not optimally aligned for running and vise versa. It is, therefore, desirable to provide a design that allows user to go from walking to running to provide greater user flexibility in multiple activities. Furthermore, while prior art prosthetic devices may have generally moved amputees toward more biomechanically appropriate gait patterns, current mechanically designed prosthetic feet do not allow for significant alterations in gait speed without losing optimal biomechanical characteristics essential with walking or running. Still furthermore, it is desirable to provide a design that allows transition from flat ground to moving up hill or from flat ground to moving downhill with ease, safety, function, and generally traversing uneven surfaces, where the prior art is lacking. There are models in the prior art such as sold under the trademark FLEX-FOOT that may provide greater energy return than other models and models that provide greater uneven ground accommodation such as sold under the trademark COLLEGE PARK. Unfortunately, neither provides both optimal energy return and uneven ground accommodation sufficiently to meet user needs.

It is now contemplated that optimal biomechanical and natural human locomotion functions cannot come solely through a relative simple mechanical device such as found in much of the existing prior art. By example in non-ankle and foot prosthetics, it has been observed in a microprocessor controlled C leg knee design by the company OTTO BOCK that amputees are able to have better gait symmetry, decreased energy expenditure, and a much greater sense of mental confidence in ambulating than non-microprocessor prosthetic knees. It is now contemplated that similar benefits could be observed through this type of design but for a broader spectrum of amputees, including trans-tibial amputees through the use of a computer controlled prosthetic ankle with appropriate sensory feedback mechanisms.

Another consideration lacking in the prior art of ankle and foot devices is the combination of aesthetics and function. A common complaint of many prosthetic foot users is that their prosthetic foot “sticks up” when they sit. This remains a problem due to the prior art prosthetic feet being affixed at a given angle with respect to the prosthesis, thus, during sitting the foot remains pointing upwards as the shin section of the prosthesis has a posterior lean when the amputee is sitting.

Furthermore, the stubbing of a prosthetic foot has proven to be a safety issue for trans-tibial, trans-femoral, and hip-disarticulation amputees alike at all activity levels. The prior art prosthetic feet have attempted to dorsiflex the foot during swing phase in the past, such as with the a prior art design under the trademark or name HYDROCADANCE, but have generally failed to provide the full range of benefits desired, such as being able to be used on a vast array of lower extremity amputees' functional abilities and amputation levels as well as provide optimal energy return characteristics, range of motion, and a life-like appearance, to name a few.

It is desirable to provide a prosthetic foot that also has a much more cosmetic effect through better simulating proper natural human locomotion and allows the foot to plantarflex during sitting to better simulate a real ankle and foot. In this manner, a user's foot and ankle would appear more normal than the tell tale sign of a prosthetic that juts unnaturally up when sitting.

Still furthermore, it is desirable to have a functional prosthetic that may also allow a user to choose from various cosmetically shaped foot shells where the prior art fails. Though prosthetic feet are not commonly seen because they are frequently covered by shoes, cosmetic appearance is a very important aspect to many amputees and other users due to current lifestyle and fashion trends. It is therefore desirable to provide a device that may allow several foot shell templates to choose from much like what is now available with upper extremity prosthetics cosmetic gloves.

What is needed is a prosthetic design utilizing a prosthetic microprocessor, sensory feedback mechanisms for various angle, time, and moment or pressure sensors, and actively providing a means for adjusting plantarflexion and dorsiflexion through prosthetic proprioception which will allow a user to transverse all necessary barriers with appropriate biomechanical precision, stability, and range of activities. Furthermore, it is desirable to provide a design for a very active user who may want to perform daily activities and run, and which provides additional stability and safety for lower activity users who simply need to traverse low level barriers with enhanced safety and stability.

Still furthermore, one of the areas of prosthetics that is very much at its infancy stages is creating prosthetic sensory feedback mechanisms. It is believed that the better the mesh between the human and machine interactions, the more functional, safe, and life-like a user's abilities will become.

Currently found in prosthetic systems used today or in prosthetic research laboratories is the sense of feel system which generally attempts to correspond to human tactile receptors in extremities. The prosthesis detects pressure and stimulates the residual limb in a manner to trick the brain into thinking it is “feeling” with the prosthesis through cerebral projections. In essence the prosthesis attempts to communicate or provide feedback to the user's brain.

Furthermore, there is also myoelectric control which generally attempts interaction from muscular control of extremity muscles. The electrical activity from the muscular actions within the residual limb is picked up by electrodes embedded in, by example, the socket system and cause the prosthetic hand to move in an intended manner. In essence, the brain attempts to communicate or provide feedback to the prosthesis.

Still furthermore, it is understood to attempt a general prosthetic brain wherein correspondence to a sort or proprioception by having the microprocessor embedded in the prosthesis, along with an array of various sensors, cause the prosthetic joint to move in a fashion that matches up to the wearers gait pattern. By example in the prior art, the C-leg system uses a microprocessor or prosthetic brain to constantly analyze how fast it should flex and extend during the swing phase of gait, as well as how much stance stability to maintain during the stance phase of gait, amongst other actions. Such design generally mimics the motion of the sound limb independent of the terrain or slope.

Although prosthetic technology has advanced in recent years, the prior art still has failed to bridge the gap between man made prosthetics and user demand and needs. Likewise, there is also a desire to enhance the body/prosthesis integration through sensory feedback mechanisms and prosthetic proprioception. Therefore, an extensive opportunity for design advancements and innovation remains where the prior art fails or is deficient.

SUMMARY OF THE INVENTION

In general, the present invention is a new and improved prosthetic joint system which provides natural human locomotion and aesthetics where the prior art fails. The present invention generally provides a sensory and time feedback system that works in conjunction with a self-contained microprocessor to control and regulate a dampening system for a joint assembly that utilizes but is not limited to magnetorheological fluid.

Without the intention of limitation, the invention may generally comprise a keel having sensors attached thereto and fixedly attached to an inner cylinder. The inner cylinder is generally disposed in a rotational manner to the outer cylinder or housing which in turn is fixedly attached to a user's lower extremity. The inner cylinder rotation is generally controlled by a dampening system that may utilize magnetorheological fluid that receives input from a microprocessor in communication with the sensors attached to the keel.

Accordingly, titles, headings, chapters name, classifications and overall segmentation of the application in general should not be construed as limiting. Such are provided for overall readability and not necessarily as literally defining text or material associated therewith.

It is therefore an object of the present invention to provide a new and improved prosthetic joint system, and more particularly, a prosthetic ankle and foot system that provides greater ease, safety, and function to a wide range of activities such as but not limited to moving from a walk to a run, transverse from flat ground to an up hill grade, or transverse from flat ground to a down hill grade.

It is a further object of the present invention to provide a new and improved prosthetic joint system which is a relatively simple design with few moving parts and thus may be easily and efficiently manufactured.

An even further object of the present invention is to provide a new and improved prosthetic joint system which is of a more durable and reliable construction than that of the existing known art.

Still another object to the present invention to provide a new and improved prosthetic joint system which is susceptible of a low cost of manufacture with regard to both materials and labor, which accordingly is then susceptible of low prices of sale to the consuming public, thereby making such economically available to those in need of such prosthetic devices.

Another object of the present invention is to provide a new and improved prosthetic joint system which provides some of the advantages of the prior art, while simultaneously overcoming some of the disadvantages normally associated therewith.

Yet another object of the present invention to provide a new and improved prosthetic joint system, and more particularly a prosthetic ankle and foot system that is well suited for most K2–K4 amputees as well as benefit transtibial, transfemoral, hip disarticulation amputees and, generally, all levels of lower extremity amputees.

Still yet another object of the present invention is to provide a new and improved prosthetic ankle and foot system that generally utilizes a keel design wherein energy return is optimized and uneven ground is more easily transversed.

A further object of the present invention is to provide a new and improved prosthetic ankle and foot system for multiple levels of amputation and addresses issues of gait for all activity levels by allowing the foot to dorsiflex through swing phase of gait thus greatly enhancing safety, decreasing mental anxiety, and increasing gait symmetry.

Still another object of the present invention is to provide a new and improved prosthetic ankle and foot system that provides cosmetic effect through better simulating proper natural human locomotion, allowing the foot to plantar flex during sitting, and features a more cosmetically shaped foot shell which may selectively be chosen from a variety of styles.

Another object of the present invention is to provide a new and improved dampening mechanism for artificial joints comprising MR fluid or other fluidly characterized system. The mechanism may be utilized on other prosthetic or orthotic joint systems. Furthermore, the mechanism may allow for retrofitting to prior art, readily available prosthetic feet and ankle joints.

An even further object of the present invention is to provide a new and improved prosthetic joint system which may provide instantaneous communication from the prosthesis to the user wherein feedback is provided such that a sense of spatial and angular orientation of the prosthetic joint is achieved.

Still further, an object of the present invention is to provide a new and improved prosthetic joint system wherein instantaneous communication from the user to the prosthesis is achieved for better regulating, controlling, or positioning the prosthesis.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings, wherein like reference numerals designate corresponding structure throughout the views, and referring in particular toFIGS. 1 and 2, reference numeral10generally refers to a new and improved prosthetic foot with ankle system, hereinafter referred to as prosthetic foot collectively, in accordance with the present invention. Invention10generally comprises keel12, foot shell14, ankle joint assembly16, dampening means or system18, a bracket assembly20, sensor system22, and attachment means24.

Furthermore, invention10is generally shown in a configuration for a right foot. It is understood that a left foot configuration is considered. It is further understood that invention10may be used on other joints and associated appendages. The term appendages should not be considered limited to limbs such as arms and legs. Still furthermore, the term joint generally refers to rotationally attached members.

Referring to the drawings and in particularFIGS. 3 and 3A, a preferred construction of keel12is generally depicted having a heel portion26with posterior split28that generally separates the heel portion26into a medial segment30and a lateral segment32. Furthermore, keel12further includes a forefront or toe portion34with anterior split36that generally separates the toe portion34into a medial segment38and lateral segment40. The area generally between heel portion26and toe portion34is generally referred to as middle portion42although it is understood that the term middle should not necessarily be construed as meaning the actual middle point of keel12.

It is further understood that a keel12may include the posterior split28and/or anterior split36or neither. It is also understood that anterior split36and posterior split28may run the full length of keel12such that keel12is generally of a two piece construction (not depicted). Furthermore, both anterior split36and posterior split28are generally along the midline44of keel12. It is understood that general split construction of keel12may generally improve ambulation over uneven ground among other beneficial ambulation.

In a preferred construction, anterior split36and posterior split28should be of sufficient width46, respectively, that a reasonable torque on keel12should reduce or prevent toe portion34medial segment38and lateral segment40and heal portion26medial segment30and lateral segment32, respectively, from contacting or rubbing past the respective segments. Such construction may reduce or prevent a “clicking” noise during walking from said contact. It is also understood that rubber pieces (not depicted) may also be included to reduce or prevent clicking and generally located in posterior split28and/or anterior split36.

In a preferred construction, curvature is contemplated at the end48of toe portion34and/or at end50of heel portion26such that a natural rollover during ambulation may be created and to provide keel12with correct positioning with respect to the ground to optimize energy return characteristics of keel12. It is still further contemplated that forefoot or toe portion34may be slightly wider than the heel portion26to provide additional stability for the user during later portions of stance phase of gait.

It is understood that foot shell14should be able to accommodate a broader toe portion34such that a cosmetic appearance may still be achieved as well as more closely to approximate the shape of a natural human foot. It is understood that other keel12shapes may be considered. Considering many shoes have a built in arch support that often causes a prosthetic foot to tilt laterally in a shoe, it is contemplated that arch52of keel12in the sagittal view will preferably be relatively high as generally depicted in the drawings. In a preferred construction, a high arch52will allow an appropriately tailored foot shell14also having a relatively high arch54, to sit flat in shoes with high arches. Additionally, the curvature will provide smooth rollover characteristics and provide the appropriate positioning of keel12with respect to the ground for loading keel12to provide appropriate biomechanical simulation. Other heights of keel12arch52and foot shell14high arch54may be considered.

In a preferred embodiment, keel12may be made from but is not limited to carbon fiber and/or carbon fiber laminates. It is understood that other materials may be used that provide light weight, high strength, high energy return spring characteristics, and may generally have relative simplicity of manufacturing. It is understood that carbon fiber usage allows for some energy return. Still furthermore, carbon fiber or other likewise materials may generally reduce the overall weight, which may be important to assist in decreased energy expenditure through limiting the inertial effects on the musculature of the residual leg, such as with the quadriceps during terminal swing phase of the gait cycle for trans-tibial amputees.

It is understood that keel12may generally consist of a thickness56to allow sufficient bending movement during stance phase of gait (heel strike through toe off) yet will be sufficiently strong or stiff enough to prevent breaking per the user's weight and activity level. It is still further understood that in a preferred embodiment, keel12may be altered to accommodate the resistant nature of bending during walking at different speeds, with varied impacts, and for various terrains which will also be discussed in greater detail below.

As will be discussed in greater detail below, a preferred construction of keel12allows for more natural and intentional mimicking of NHL and may provide the energy return at the appropriate time during the gait cycle as with NHL, predominantly at or just before toe-off to simulate gastrocnemious contraction.

In a preferred embodiment, middle portion42of keel12may be thicker to allow additional strength for attachment to ankle joint assembly16. It is also contemplated that keel12may be flexible enough to have sufficient bending of keel12to compensate for NHL shock absorption mechanisms which may have been lost due to amputation such as the movement that can be found in the structure of the human foot like the ligamentous and fibrous bands, as well as with the compressibility of the meniscus pad found under the calcaneous. Thus, it is understood that such construction may allow for a potentially smoother gait. Additionally, increased keel12flexibility may allow for better uneven ground accommodation and enhanced energy return. The keel12thickness and compressibility may also be tailored to the user's weight and activity level to provide optimum characteristics.

In another preferred embodiment, keel12may utilize a split toe design wherein the split may be offset toward one side (not depicted) in order to allow a cosmetic foot shell14with a separated big toe in order to allow the user to wear sandals. It is understood that keel12may not include any split portions and generally remain with a full non-split keel12. It is further understood that invention10may be adapted to utilize, retrofit, or integrate with existing known keels12in the prior art.

Still furthermore, it is understood that keel12may be integrally formed with foot shell14. It is further understood that invention10may utilize an attachment means (not depicted) wherein invention10may be attached to existing keel12designs available in the art.

Foot Shell

In a preferred construction, foot shell14may be generally anatomically correct and may further include a sufficiently high arch54. The keel12foot would lock into the foot shell14by means that are similar to other internal keel prosthetic feet available such as with FLEX-FOOT designs and OHIO WILLOW WOOD PATHFINDER FEET. It is understood that a SPECTRA sock may be used over foot shell14to reduce or prevent squeaking noises arising from the keel rubbing against the foot shell14. The same internal design of this said foot could be used with either a left or right foot shell14for simplicity in manufacturing.

In a preferred embodiment, it may be desirable to provide a foot shell14that is generally thin as to not limit the motion of the foot design through stiffness. By example, the OTTO BOCK1C40foot provides an optimal foot shell that is generally thin and flexible whereas FLEX-FOOT designs are more generally thicker and less flexible. It is contemplated that a thinner foot shell14allows for full keel12dynamics although the invention10should not necessarily be limited to such.

In a preferred construction, keel12is removably attached to foot shell14. It is contemplated that conventional means known in the art may be utilized. In a preferred construction, keel12may generally attach to foot shell14by having a small protrusion extending out within the inside of the foot shell14in which keel12snaps in place underneath.

Attachment Means

Invention10generally includes attachment means24to a user's lower extremity (not depicted). Attachment means24may be but is not limited to a male pyramid58. It is understood that other conventional attachment means24known in the art may be used such as but not limited to threaded screws that mateingly engage, removable and non-removable bolts, removable pins, and so forth may be utilized. Furthermore, it is understood that male pyramid58may be of a female configuration and so forth.

Ankle Joint Assembly

Referring once again to the drawings and in particularFIGS. 4,4A,4B, and4C, ankle joint or joint assembly16generally comprises a housing or outer cylinder60that is generally connected to attachment means24. In a preferred construction, outer cylinder60is generally in a fixed position or non-rotational position relative to lower extremity and attachment means24. Outer cylinder60generally includes an interior cavity62and a center axis64. Furthermore, outer cylinder60may include first side cover66, second side cover68, and a range of rotation restrictor bar70.

It is further contemplated that range of rotation restrictor bar70may include cavity72which may generally be located along perimeter74of outer cylinder60such that electromagnet76, which will be discussed in greater detail below, may also generally be installed in a relatively fixed position relative to lower extremity and attachment means24. In a preferred construction, outer cylinder60may be generally constructed of non-magnetic non-conductive material as will be described in greater detail below. In a preferred embodiment, electromagnet76is generally disposed in cavity72which may also be generally disposed in range of rotation restrictor bar70.

Once again referring to the drawings and in particularFIGS. 5,5A,5B,5C, and5D, generally disposed in outer cylinder60interior cavity62is inner cylinder80. In a preferred construction inner cylinder80generally attaches to keel12in a fixed or non-rotational manner such as but not limited to bracket assembly20which will be discussed in greater detail below. It is understood that inner cylinder80generally rotates around outer cylinder60center axis64. In a preferred embodiment, inner cylinder80is made from non-magnetic material in total or in part which will also be discussed in greater detail below.

Referring toFIGS. 6,6A, and6B, in a preferred construction, shaft82generally is positioned and aligned along the interior cavity62of outer cylinder60along center axis64whereby inner cylinder80is generally attached to shaft82. Furthermore, shaft82generally aligns inner cylinder80and outer cylinder60. Shaft82is generally axially aligned and connected by outer cylinder60first side cover66aperture84and second side cover68aperture86. Shaft82may be made from non-magnetic material or magnetic material as will also be discussed in greater detail below.

As discussed above, outer cylinder60stays in a relatively fixed position relative to lower extremity of user and generally secures shaft82such that shaft82may rotate along center axis64. Inner cylinder80is generally attached to shaft82and rotates relative to user lower extremity. In a preferred embodiment, shaft82is in a relatively fixed attachment to inner cylinder80. It is understood that other conventional rotational means may be provided wherein outer cylinder60is in a relatively fixed position relative to user lower extremity and inner cylinder80is generally free to rotate respective to user lower extremity.

Inner cylinder80is generally constructed such that rotation along center axis64is limited. In a preferred embodiment, inner cylinder80includes top stop88(FIG. 7) which contacts outer cylinder60range of rotation restrictor bar70. Furthermore, inner cylinder80may include bottom stop90(FIG. 7) which contacts outer cylinder60range of rotation restrictor bar70.

The inner cylinder80may be made hollow or with lightweight core to decrease weight. It is understood that inner cylinder80may be weighted, filled with a deformable semi-solid material, fluid filled, or other such means where the center of gravity (not depicted) of the inner cylinder80may move relative to the ankle joint assembly16.

It is further contemplated that inner cylinder80may include a cavity78for locating elements of the invention10and for possibly providing a water tight compartment for electronics or power source130used in association with invention10which are discussed in more detail below.

Referring generally toFIG. 7, it is understood that the human ankle has a general range of rotation of about 15 degrees up (from horizontal92) and a general range of rotation of about 45 degrees down (from horizontal92). In a preferred embodiment, inner cylinder80is generally restricted from rotating up past 15 degrees by top stop88contacting outer cylinder60range of rotation restrictor bar70. Furthermore, inner cylinder80is generally restricted from rotating down past 45 degrees by bottom stop90contacting outer cylinder60range of rotation restrictor bar70. It is understood that the general range of rotation may be increased or decreased and the above example should not be considered limiting. It is contemplated that greater range of motion or rotation may be desired for certain activities requiring more general flexibility and, likewise, more restricted range of motion or rotation for other activities where less flexibility may be desired.

Dampening System

Once again referring to the drawings and in particularFIGS. 8 and 8A, dampening means or system18, generally refers to a means for controlling keel12rotation in association with and respective to the user. Dampening system18may generally include electronic control, mechanical function, fluid dynamics, and combinations thereof It is understood that invention10contemplates numerous means such as hydraulic, magnetic, mechanical or other constructions wherein the dampening, general control, or characteristics of the rotation of the joint assembly16is achieved.

In a preferred construction, magnetorheological or MR fluid94is generally used for dampening the rotation of inner cylinder80around the center axis64of outer cylinder60whereby the MR fluid94state of liquidity or viscosity is relatively controlled by selectively charging the MR fluid94via use of a permanent magnet or electromagnet76. By example, where no or little dampening is desired, the MR fluid94is not charged and generally stays in a relatively liquid state thereby creating little to no impediment for inner cylinder80from relatively freely rotating around center axis64of outer cylinder60. When dampening is desired, the MR fluid94is selectively charged to harden or somewhat solidify the MR fluid94so that generally a viscous clutch, brake or impediment is created whereby the rotation of inner cylinder80around center axis64of outer cylinder60is slowed and/or halted.

It is also contemplated that MR fluid94may further act as a general lubricant for ankle joint assembly16outer cylinder60and inner cylinder80. It is still further contemplated that invention10may be utilized with hydraulic or other adjustable damper means to control plantarflexion and dorsiflexion. It is understood that the current invention10may incorporate other means such as generally fluid type dampening other than MR fluid94. Likewise it is understood that invention10may be carried out with no per se fluid and relay on magnetic and/or mechanical dampening.

In a preferred embodiment, inner cylinder80further includes a conductive surface96which may integrally be part of inner cylinder80or formed in as cover98. Conductive surface96should generally be made from a material that is capable of carrying or conducting an electric or magnetic charge and the term conductive should not necessarily be considered to be limiting. Conductive surface96may be made from metal, plastic with metal fibers, or other generally conductive materials or variations thereof. Conductive surface96may include a first side100and a second side102such that a generally larger surface area is contemplated for interaction with MR fluid94.

Furthermore, conductive surface96may be generally near or in communication with shaft82. Conductive surface96may include apertures104and106for generally attaching with shaft82. It is contemplated that shaft82may be of a conductive, metallic, or the like material whereby MR fluid94would also interact with shaft82in possible relative conjunction with conductive surface96. Still furthermore, conductive surface96may have serrations108, ridges or the like.

As discussed above, outer cylinder60is generally formed from non-magnetic or conductive material. In a preferred construction, outer cylinder60includes conductive surface or strip110which may be integrally formed with outer cylinder60or as separate element112as generally depicted. Furthermore, conductive surface or strip110have serrations114, ridges or the like (FIG. 4A). In general, outer cylinder60strip110is aligned with inner cylinder80conductive surface96. In a preferred construction, strip110may further include a first side117and a second side119which may generally interact with inner cylinder80conductive surface96first side100and second side102, respectively. Still furthermore, strip110may generally connect or be in contact with shaft82. Conductive strip110may include apertures116and118for generally attaching with shaft82.

The inner cylinder80conductive surface96and outer cylinder60conductive strip110may include serrations114, ridges or the like in a generally radial direction from center axis64in order to increase or help MR fluid94lock down in the presence of an electric or magnetic field and thereby increases direct shear mode response. It is further contemplated that such construction would additionally increase the surface area for MR fluid94communications and interaction.

It is contemplated that void, space, or cavity120is generally created between outer cylinder60and inner cylinder80and generally filled with MR fluid94. In a preferred embodiment, inner cylinder80is generally disposed in outer cylinder60such that a general close proximity may be achieved to limit the amount of MR fluid94needed with possible exception to areas specifically where the given distance would be optimized for fluid dynamic characteristics. Furthermore, MR fluid94may act as a general lubricant to decrease friction between the inner cylinder80and outer cylinder60during rotation. It is also contemplated that having the inner cylinder80and outer cylinder60in a relative close proximity would increase or benefit the structural lateral torque stability of the dampening system18.

It is still also contemplated that shaft82may be made of conductive or magnetic properties in order to assist or decrease or prevent possible leakage of the MR fluid94. By example, such construction may generally make the MR fluid94generally more viscous and not as likely to leak through holes or potential holes in seals.

Now referring toFIG. 9, in a preferred construction, electromagnet76is generally in communication or contact with outer cylinder60conductive strip110, which is in communication with or contact with MR fluid94, which in turn is in communication or contact with conductive surface96of inner cylinder80, thereby forming electric or magnetic flux circuit122.

Spacers124and126made from but not limited to nylon may also be utilized in a preferred construction and generally be placed between inner cylinder80and conductive strip110to decrease or prevent completion of circuit122aside from charging the MR fluid94in completion of circuit122.

Power source130is generally in contact or communication with electromagnet76via wires128. It is contemplated that the dampening system18may have a low draw of energy consumption, and thus a small battery132may be utilized. In a preferred construction, battery132would preferably be lithium ion in nature but is not limited to such. Power source130can be placed anywhere on the prosthesis for ease of replacement and may include an attachment port (not depicted) for recharging. Additionally, for optimizing the weight distribution, power source130can be placed externally such as on the socket or pylon. It is also contemplated that the power source130could selectively be placed higher, keeping a higher center of gravity for minimalizing inertial forces during running. As discussed above, power source130may generally be located in cavity78of inner cylinder80.

Furthermore, electromagnet76may also incorporate a safety features to allow a manual lock such as but not limited to a permanent magnet for the event of power loss. It is contemplated that as a potential safety backup, wherein by example a power source130level were to decrease to a certain level, a reverse polarity may be created to cause the permanent magnet to slide into position to lock joint assembly16or dampening system18. By example, a permanent magnet may be slid into a desired position to create a positive lock at a fixed angle to allow the user to ambulate with some or all of the motion coming from the keel12compression such as may be found in prior art standard prosthetic feet. Once recharging or power source130returns to a relative normal condition, the polarity would again reverse back to its normal state, causing the permanent magnet to move out of position, and invention10may then operate via the electromagnet76. As power levels become low, an indicator, such as audible or vibratory alert may be used.

It is further contemplated that joint assembly16and dampening system18may include a magnetorheological dampening which may operate by both direct shear and pressure driven mode to generally increase the resistance ability of the joint assembly16. As stated above, dampening system18may of numerous construction contemplated within the scope of invention10.

Referring to the drawings andFIG. 9Ain particular, it is still further contemplated that a mechanical based servo/permanent magnet system133may be used in conjunction with or as opposed to electromagnet76. It is further contemplated that tapered magnetic and nonmagnetic pieces which are joined together with which the permanent magnet slides against, via a servo or motor, in order to vary the magnetic field interacting with conductive piece number110. In a preferred construction, magnet system133may include a small servo or motor mechanism135, such as but not limited to one utilizing gears, to slide back and forth.

Additionally, mechanical based servo/permanent magnet system133may include a hydraulic adjustable valve (not depicted) to control the amount of MR fluid94passing between outer cylinder60and inner cylinder80. The valve may be controlled as well by a small servo or motor mechanism. It is contemplated that mechanical based servo/permanent magnet system133may require less energy consumption and may therefore be beneficial in certain applications. Dampening system18may also generally include spring system, dorsiflexion means or dorsiflexion spring system137. It is contemplated that dorsiflexion spring system137may cause the ankle joint assembly16to dorsiflex during swing phase of gait. Dorsiflexion spring system137may comprise a spring of conventional nature, hydraulic piston, combinations of both or other conventional spring biased devices known in the art. Dorsiflexion spring system137may be attached or located anteriorly or posteriorly to the dampening system18or ankle joint assembly16(compression or extension spring, depending on the location for shortening or lengthening, respectively).

The spring load resistance may be changed through adjusting the spring drive length, changing to a lighter or heavier spring, or adjusting spring placement.

Bracket Assembly

Referring to the drawings and in particularFIGS. 10 and 10A, in a preferred embodiment, bracket assembly20would generally comprise a medial bracket134having aperture136and lateral bracket138having aperture140wherein aperture136and aperture140are generally axially aligned and receive shaft82. Furthermore, medial bracket134aperture136and lateral bracket138aperture140may be generally in a circular shape142with a flat portion144for matingly engaging shaft82circular portion146and flat portion148(FIG. 6B).

In a preferred construction bracket assembly20is pivotally connected to outer cylinder60such that the rotational movement is along center axis64. It is understood that other attachment means may be contemplated wherein bracket assembly20is connected to inner cylinder80in a generally fixed manner and yet in a pivotally rotational manner with outer cylinder60. It is contemplated that bracket assembly20is attached to keel12by attachment means150such as but not limited to screws152,154,156, and158. Other conventional attachment means150may be used wherein keel12may be easily and quickly be removed for other configurations of keel12.

It is further understood that bracket assembly20may be of a single piece construction (not depicted) wherein medial bracket134and lateral bracket138are joined in the middle on the distal aspect to possibly provide additional stability. The contouring of the brackets assembly20is preferred to minimize weight and optimize strength. In a preferred construction, apertures160,162,164and166are formed to reduce the material used in generally forming bracket assembly20.

In a preferred construction, bracket assembly20is made from material that is light weight and provides minimal torque movement. Materials may be but are not limited to composites, plastic, laminated material, aluminum, or titanium. It is understood that alterations to the shown design of the bracket assembly20may be contemplated to provide other configurations for optimal strength and minimal weight.

Washer (not depicted) may be used between the outer cylinder60and bracket assembly20to generally decrease friction. Washer may be recessed into the brackets and/or outer cylinder to allow more precision fit of components against each other.

Joint Assembly Placement

Again referring to the drawings and in particularFIGS. 11,11A, and11B, in a preferred construction, the placement of the joint assembly16will be such that center axis64of rotation will generally fall through an anatomical weight line region168. It is understood that typically according to the anatomical chart, weight line region168is approximately 28.2% of the foot length anterior to the posterior aspect of the skeletal structure of the foot. It is contemplated that joint assembly16rotation along center axis64rotation is generally along an anatomical center of rotation170of a natural ankle joint. It is understood that this position is in relatively close proximity to the posterior aspect of the foot, and as such the bracket assembly20for joint assembly16may begin just posterior to the weight line region168and run forward for support. It is further contemplated that positioning of the joint assembly16will provide additional keel12heel portion26compression abilities and uneven ground accommodation.

It should also be noted that while the keel12heel portion26will provide some compressibility from heel strike to foot flat, the majority of the action will come about through true plantarflexion of the keel12through the magnetorheological dampening in order to better mimic NHL and provide for optimal push off characteristics at toe off, which is discussed below.

Furthermore, an inversion/eversion damper system (not depicted) may be utilized at the base of the dampening system18to further accommodate uneven ground. This may include bumper systems, compressible materials such as urethane, joint systems, and the like.

Feed Back Sensor System

Referring to the drawings again and in particularFIG. 12, in a preferred embodiment, invention10may utilize a feed back sensor system22. It is contemplated that feed back sensor system22will provide the dampening system18either directly or indirectly information such as but not limited to weight distribution on keel12, forces generated on keel12, impact times on portion of keel12and so forth for determination of user gait cycle to automatically control joint assembly16operations. Sensor system22may also include a strain sensor, moment sensor, pressure sensor, or the like that may communicate with microprocessor unit172via wires186as well as power source130. Furthermore, feed back control system22may include a time sensor or real time clock and angle sensor to compare angular velocity and acceleration relative to center axis64of dampening system18.

It is contemplated that invention10may further but not necessarily include a microprocessor unit172which communicates with sensor system22and in turn generally controls or communicates with the dampening system18of joint assembly16which will be discussed in greater detail below. It is understood that the term, feed back sensor system, should not be considered limiting.

It is contemplated feed back sensor system22may be generally located on keel12. It is still further contemplated that feed back sensor system22may include heel sensor system174generally located on heel portion26and toe sensor system176generally located on toe portion34.

Furthermore mechanical or liquid pressure/force strain sensors may be included within or part of dampening system18to determine force generally on heel portion26and/or toe portion34. It is understood that other types of known sensors in the prior art may be used such as sensors that measures microscopic bending of the titanium tubular pylon to determine pressure on heel and forefoot.

In a preferred construction, heel sensor system174may further include sensor178and180, on heal portion26medial segment30and likewise on heal portion26lateral segment32respectively. Furthermore, toe sensor system176may further include sensor182and184on toe portion34medial segment38and likewise on toe portion34lateral segment40, respectively. It is contemplated that more sensors may be utilized and located around other portions of keel12. In a preferred construction sensors and sensor systems communicate with dampening system18and/or microprocessor172via wires186.

Microprocessor

It is contemplated that microprocessor unit172will give real time gait analysis throughout the gait cycle as well as control the MR fluid94liquidity, solidification, or viscosity. It is contemplated that microprocessor unit172may be of a similar design to that of the OTTO BOCKC-LEG, but should not be considered limited to such. This design may incorporate time sensors or real time clock188, angular sensor190, heel portion26load, force, strain, or moment sensor or sensors192, and toe portion34load, force, strain, or moment sensor or sensors194. It is also contemplated that moment sensors or strain gauges may be utilized.

Time sensors or real time clock188may be utilized to regulate events such as allowing invention10to lose all plantarflexion resistance when the user is sitting, thus, allowing the foot to be at a natural angle which is discussed in greater detail below. Furthermore, time clock188could regulate aspects of gait based on a profile of optimal timing for the user. It is further contemplated that some of the discussed functions may not necessarily only be based on time factors, but may also be based on movement or time and movement input to microprocessor. In a preferred construction, angular sensor190may be incorporated into the inner cylinder80and/or outer cylinder60to determine the relative angle of the keel12to user lower extremity. Angle sensor190may be fixed in the joint assembly16to determine the degree of rotation between inner cylinder80and outer cylinder60. It is further contemplated that a level device (not depicted) may be used to generally determine the keel12angle relative to ground.

It is still further contemplated that microprocessor unit172could be programmed to control speed and amount of plantarflexion at keel12heal portion26striking of the ground also referred to as heel strike. It is also contemplated to utilize existing prior art such as OTTO BOCK C-LEG for control mechanisms. Furthermore, it is contemplated dynamic factors could be programmed to denote how “hard” a patient generally walks. The general amount of plantarflexion used in walking may be set to determine push off characteristics. For example, the speed and amount of dorsiflexion of the foot after toe off may be set. Each of these characteristics may be set for normal walking as well as adapt to change as the user gait changes.

The sensory feedback systems22may cause the microprocessor unit172to change the MR fluid94damper characteristics as speed increases or decreases, or when walking on non-level terrain.

Each aspect of ankle and foot gait characteristics may be modified through in order to appropriately tailor the user's gait for perfect symmetry, safety, and function of all activities.

In a preferred embodiment, microprocessor unit172may be programmed with various memories or programs196, include communication electronics198for interfacing or programming, and provide audible signals200or vibratory signals for warnings of malfunction, power level, etc.

Microprocessor unit172could be located just anterior to the ankle joint assembly16on top of keel12or may be located on the inside of the inner cylinder80, as generally discussed above. It is further contemplated that microprocessor unit172may be located on a lower extremity prosthesis wherein a user is missing possibly above knee or below knee but above ankle. In another preferred embodiment, invention10may work in conjunction with an artificial knee wherein microprocessor unit172could be utilized for both joint functions.

As generally discussed above, power source130is contemplated for electric supply for dampening system18. It is further contemplated that power source130may be located in or integrally formed with microprocessor unit172and provide power for microprocessor unit172. In a preferred construction, wires173may connect microprocessor172to power source130. It is still further contemplated that microprocessor unit172may include a current supply and power or battery management system202for further optimizing power consumption. System202may include on and off timers for powering down while the invention is at rest for periods of time. Typically, unless the user is sleeping, there will be some change in angle or force at any given time frame when the user is supporting weight. It is contemplated that invention10may include an automatic system (not depicted) such that if no force change is detected on sensor system22, during a designated time, invention10may power down to conserve energy. In a preferred embodiment, invention10would power down automatically when not being worn by the user whereby the user would not have to manually turn invention10off.

It is also still further contemplated that power source130may be of a regenerating nature wherein the power source130is re-supplied through mechanical means such as Faraday type device. Furthermore, known technology for self winding mechanisms with rotors, as found in self winding or self powering watches may be utilized. In a preferred embodiment, microprocessor unit172may be wirelessly programmed or controlled such as through wireless technology found in modem pacemakers/defibrillators. It is contemplated that a user could wirelessly regulate, command, or program specific functional parameters on demand such as modifying the dampening system18incrementally and selectively through a remote control. Likewise, invention10may include a hardwired controller (not shown) generally mounted in a relatively accessible manner on the invention10.

As will be discussed in greater detail immediately below, microprocessor172may be used in conjunction with a myoelectric sensor system400and/or a proprioception system300. In a preferred construction, microprocessor172may be utilized as the primary and only electronic control and processing device for invention10. It is understood, however, that multiple units may be used that work in conjunction or separately to perform the various tasks.

Referring again to the drawings and in particularFIG. 12A, in a preferred construction of invention10, prosthetic proprioception system300may be included. It is contemplated that the invention10may provide instantaneous communication or signals from the prosthesis to the user wherein feedback is provided such that a sense of spatial and angular orientation of a prosthetic joint is achieved.

For reference,FIG. 12Cgenerally illustrates elements of a natural human system for proprioception feedback pathway. Furthermore,FIG. 12Dgeneral illustrates a flow chart depicting elements of a natural human system for proprioception feedback.

It is understood that in the human body, the brain analyzes the required movements of our extremities as well as has knowledge of the positioning of our joints and orientation in space. Small proprioceptor sensors in the human muscles and joints, such as joint kinesthetic receptors, neuromuscular spindles, and neurotendinous receptors, send sensory information to the brain to tell it where the limb is orientated in space as well as its movements such as stretching of the muscles or bending of the joints.

It is also understood that there are systems in the prior art which relate to pressure sensor on the prosthetic foot or hand which may relay information through a small microprocessor and then stimulate the limb in a similar fashion, thus tricking the brain in thinking that the wearer is “feeling” with the prosthetic limb. It is contemplated that invention10may read the angular position and change within the prosthetic joint and stimulate the limb308in a designated manner, thus providing what may become a subconscious feedback of the position and angle of the limb's spatial orientation.

It is contemplated that invention10may provide greater safety through “knowing” the position of the prosthetic joint in space. By example, “knowing” or “feeling” that the ankle joint is plantar flexing excessively due to wearer beginning to walk down a hill.

Furthermore, it is also contemplated that there will be a decreased energy expenditure through providing a more natural gait pattern as well as providing an enhanced mental confidence in the prosthesis and therefore greater functionality. Likewise, the user may have a sense that the prosthesis is more of a part of them through enhanced human/machine interaction.

It is contemplated that the user's brain will learn the sensory feedback from the system as subconscious proprioception or cerebral projections.

It is contemplated that the user would generally connect, communicate, interact with joint assembly16via communication means or system302. It is further contemplated that a separate microprocessor304may be utilized or microprocessor172or even a combination thereof. It is further understood that prosthetic proprioception system300may be utilized on other joints as well as ankle joints or other prosthetic joints, such as knee, hip, hand, elbow, and shoulder.

Furthermore, it is contemplated that the prosthetic proprioception system300may be utilized on an individual that has lost feeling or lost the sense of proprioception or control in their natural extremity.

In a preferred construction, it is contemplated that feedback mechanisms306may include pressure variance with angular change, pressure movement with angular change, electrical impulse to limb308with angular change, vibratory variance with angular change, and other conventionally known methods. Furthermore, it is contemplated that prosthetic proprioception system300may utilize angle or positional sensor in conjunction or separately with a sensor to detect resistance to angular change of a prosthetic joint.

Now referring toFIG. 12E, generally illustrated is a flow chart depicting a preferred embodiment of invention10. It is contemplated that integration of the various sensors and feedback may be controlled by microprocessor172or through an independent processing system or combination thereof.

Referring now toFIG. 12Fanother preferred construction is generally depicted wherein keel12, dampening system18, ankle joint assembly16, sensor system22is in general communication with wires310through microprocessor312, power source314, sensory stimuli contact316and wires318. It is understood that microprocessor312may be microprocessor172or through an independent processing system or combination thereof. Power source130may also be used Sensor system22may include angle or position sensor320. Likewise,FIG. 12Gis a general flow chart of a preferred embodiment invention10as discussed.

Now referring toFIG. 12H, another preferred embodiment of invention10is generally depicted wherein the prosthetic is directed to a non-ankle joint although a prosthetic hand is generally illustrated, it is understood that invention10may be utilized on other joints, prosthesis, and combination thereof. Socket322, frame324, sensory stimuli contact326, wires328, cosmetic cover hand shell330, internal hand components332, hand motor334, hand connector piece336, power source338, microprocessor340, angle/position sensor342, and hand connection piece344are generally shown working in communication. Likewise it is understood that power source338may be utilized separately or in conjunction with power source130and may also be but is not limited to a myoelectric battery. It is also understood that microprocessor340may be microprocessor172or through an independent processing system or combination thereof.

Myoelectric Sensor System

Once again referring to the drawings and in particularFIG. 12B, a preferred construction of invention10may further include a myoelectric sensor system400wherein a generally closed loop sensory feedback system is contemplated. Myoclectric controls and/or myoclectric sensor system400may provide a prosthetic system wherein instantaneous communication or signals from the user to the prosthesis is achieved for better regulating, controlling, or positioning the prosthesis. It is understood that the human body produces electrical signal through muscular and other activity.

It is contemplated that in a preferred construction, dampening system18is generally controlled by the myoclectric sensor system400. It is understood that myoelectric sensor system400may not necessarily cause movement of the ankle joint assembly16, but rather is allowing the user to adjust the rotation or slow down the angle progression during stance. The joint assembly16movement may still generally be achieved through natural biomechanical movement during ambulation. The dampening system18, corresponding sensor system22such as pressure, and myoelectric sensors system400generally limit how fast the ankle joint assembly16rotates. It is contemplated, therefore, anatomical musculature control of the lower extremity prosthesis, or more specifically the ankle joint assembly16, is achieved.

It is further understood that myoelectric sensor system400may be utilized on other joints as well as ankle joints or other prosthetic joints, such as knee, hip, hand, elbow, and shoulder. Likewise, it is understood that myoelectric sensor system400and proprioception system300may be both included in a preferred embodiment or separately. It is understood that some myoelectric systems are known for use in upper extremity prosthetics and knee systems.

Myoelectric sensor system400may include stimulators or controls402which may be placed on the residual limb404of a user (i.e., on the pretibial and gastrocnemious group for transtibial amputees) to control or manage dampening system18. By example, as the user fires their gastrocnemious muscle group, such as they naturally would during the midstance to toe off portion of the gait cycle at the beginning of midstance, invention10may increase resistance in the dampening system18and therefore provides greater resistance toward toe off portion of the gait cycle. User may then actively control their joint angle during ambulation as with a real foot.

It is contemplated that a preferred construction may enhance muscle tone and muscle strength in residual limb404and consequently may improve circulation. Of note, 70% of amputations are secondary to circulatory insufficiencies. Invention10may therefore prevent higher level amputations as is often the case with patients with severe circulatory insufficiencies.

Accordingly, invention10may also provide control for the user, increases safety, symmetry, confidence during ambulation, and further controls plantar-flexion and dorsi-flexion. Likewise, it is contemplated energy or power required myoelectric sensor system400and/or proprioception system300would be minimal relative to other power generally contemplated by invention10.

Generally referring to the drawings and in particularFIGS. 13,14,14A, and14B, the following changes to the invention10in general or dampening system18in specific may be allowed to best mimic natural human locomotion during ambulation.

Toe Off

Generally referring toFIG. 13, as the user completes the toe off position204of the gait cycle, the dorsiflexion spring system137may cause invention10to immediately begin to go into dorsiflexion, as occurs in normal human locomotion, to decrease the likelihood of stubbing the toe portion34during swing phase of gait. Once full dorsiflexion occurs, MR fluid94resistance of dampening system18remains at or near zero until heel strike position206when heel sensor system174detect pressure or load greater than zero. The rate of dorsiflexion can be programmed to allow for optimal safety and symmetry.

The spring load resistance of dorsiflexion spring system137, may be modified or changed through adjusting the spring drive length, changing to a lighter or heavier spring, and/or through increasing dampening system18resistance, in order to optimize this characteristic for the user's activities. By example, if the user intends to run, the dorsiflexion spring system137resistance characteristics may be increased to overcome the inertial effects of the invention10during running.

Swing Phase

Throughout swing phase, invention10may remain in dorsiflexion until heel strike position206in order to generally shorten the extremity.

Heel Strike to Foot Flat

Heel strike position206cushioning and invention10plantarflexion comes about mainly though true ankle plantarflexion and not through heel compression. While the heel portion26may compress slightly, the ankle joint assembly16plantarflexion will constantly be monitored to provide fluid, smooth, roll-over characteristics and provide optimal push off characteristics through keel12loading. As heel portion26load, moment sensor192, or heel sensor system174detect contact, foot plantarflexes with angle/time angular velocity using MR fluid94plantarflexor resistance. As the force of heel portion26contact increases, the MR fluid94resistance will increase to limit the force of plantarflexion.

It is contemplated that this will generally simulate the tibialis anterior action in human biomechanics at heel strike position206. Once the toe portion34load sensor194or toe sensor system176is greater than or near zero at foot flat position208, the angle sensor190or sensor system22in general may predict angular change per time for heel portion26strike pressure sensor or heel sensor system174. If angle/time is too slow, according to heel portion26strike pressure or heel sensor system174, MR fluid94resistance decreases. This would generally correspond to the slowing down of gait speed. If angular change increases with respect to previous step (going down a hill for instance), MR fluid94damper keeps plantarflexing until toe portion34load sensor or sensor system176is greater than zero.

It is contemplated that invention10will generally adapt to the surrounding environment automatically, in order to maintain proper stability, safety, and function. A similar effect would occur if the user were wearing a high-heeled shoe. It should be noted that at heel strike position206with many other prosthetic feet designs, the plantarflexion movement is obtained through heel compression. In a preferred construction, invention10does allow slight compression for shock absorption and smoothness of gait, but just as occurs biomechanically, the plantarflexion movement occurs through the ankle joint assembly16bending with an eccentric contraction of the tibialis anterior and not necessarily entirely through heel compression. It is contemplated that, the dampening system18allows for the controlled plantarflexion, mimicking the tibialis anterior movement, while the heel or heel portion26compression may mimic natural heel fatty pad compression for general shock absorption.

Foot Flat to Mid Stance

With increased heel sensor174pressure during heel strike position206to foot flat position208, MR fluid94damper dorsiflexion resistance increases from foot flat position208to mid stance position210in order to provide increased plantarflexion during later portions of gait to allow increased spring off from invention10from heel off position212to toe off position204. This may mimic the action of the gastrocnemious muscles during walking.

Mid Stance to Heel Off

With increased heel portion26sensor pressure or generally indication from heel sensor system174during heel strike position206to foot flat position208, MR fluid94damper dorsiflexion resistance increases to provide increased plantarflexion during gait until toe portion34load sensor or toe sensor system176equals zero during toe off position204. It is contemplated this may allow slight dorsiflexion to a certain angle for smoothness of gait but remains in some plantarflexion for push off from heel off position212to toe off position204. During this section of gait, the MR fluid94dampening system18may lock out to provide the necessary plantarflexion for push off; however, the angle which the dampening system18of ankle joint assembly16will lock out will vary according to angular sensor190, heel load sensor192during heel strike206, and angular velocity determination, etc. During this portion of gait, the invention10goes into some dorsiflexion, however, the dorsiflexion is obtained in a preferred embodiment through keel12loading, therefore leading to increased push off at toe off position204.

Heel Off to Toe Off

In natural human locomotion, the plantarflexor muscles fire at this stage in the gait cycle to maintain ankle angle or provide slight plantarflexion for push off. It is contemplated that through invention10, the plantarflexion is already obtained through the midstance phase of gait and having the dampening system18lock out at a preferred or certain angle; however, it has been stored through keel12loading and is released in spring off from heel off position212to toe off position204thus simulating gastrocnemious induced plantarflexion of the foot. After heel portion26load sensor192equals zero and toe portion34pressure sensor nearly approaches zero, MR fluid94resistance goes to zero and allows for dorsiflexion spring system137to dorsiflex foot during swing phase.

Alterations From Normal Ambulation Function

A common complaint of many prosthetic foot users is that their prosthetic foot “sticks up” when they sit. This un-cosmetic appearance is eliminated through invention10by allowing the prosthetic to lose all plantarflexion resistance when the user is sitting, thus, allowing the foot to be at a natural angle. In a preferred construction, it should be noted that the dorsiflexion spring system137should not provide too much resistance to plantarflexing as to prevent the necessary motion in sitting, or to alter the gait pattern negatively. During sitting, it is contemplated that the dampening system18may prevent dorsiflexion while allowing plantarflexion to be free in order to provide greater cosmetic appearance. The sensor system22(time, angle, moment, etc) may determine if the user is sitting and will correspondingly allow invention10to plantarflex.

It is also contemplated that heel pressure, as generally determined by heel sensor system174, that occurs for a given time period such as a few seconds, with no toe pressure, as generally indicated by toe sensor system176, will indicate or allow plantarflexion for sitting wherein little to no resistance is created.

It is further contemplated that a negative bending moment on the heel portion26could signal the microprocessor unit172that the user has sat down and to have free plantarflexion abilities. A preferred embodiment may be by planting the heel portion26into the ground after sitting and pulling back. This action would generally not occur in normal walking and may therefore be a good indicator for sitting action.

In a preferred construction, invention10is constantly updating the sensory feedback system22information to the microprocessor unit172wherein the user can change heel heights of a shoe without changing any settings. If the user goes to a higher heel height for instance, the sensors system22will still read the moment forces and consider that the user is merely walking down a hill and, thus, the gait will not alter. The dampening system18can further be designed to allow a certain amount of heel height clearance accommodation. It is contemplated to allow about 15 degrees of dorsiflexion and about 45 degrees of plantarflexion to allow proper natural human locomotion and to allow for heel height changes. It is further contemplated that more or less degrees of rotation may be desired to allow for more or less of a range of motion to achieve natural human locomotion. It is understood that natural human locomotion may be altered or generally defined by such things as a users desire or need to wear high-heeled shoes.

In a preferred embodiment, invention10may have special modes to allow the user to lock the keel12or joint assembly16out at a given angle, such as for skiing, or can change the characteristics for other specific activities where limited motion is required. It is understood that various methods of implementing such is contemplated.

Stumbling or Walking Up Steep Hill

If toe load sensor194is greater than zero before heel load sensor192is greater than zero, then MR fluid94resistance will remain at or near zero or may fully lock up to stabilize joint assembly16if not fully dorsiflexed already, to continue to allow for full dorsiflexion via dorsiflexion spring system137. In walking up a hill, this movement would still be similar to natural human locomotion and may benefit the user by decreasing or reducing hyperextension of the knee, as is found in the prior art.

Walking Down Hill

As angular sensor190determines that there is a greater angular change since heel strike position206and foot flat position208, wherein toe load sensor194maybe greater than zero, invention10may provide slightly less dorsiflexion resistance from heel off position212to toe off position204to allow the user to descend down hill according to proper natural human locomotion.

Going Up Stairs

It is understood that generally a foot will already be in dorsiflexion after previous step and will remain in dorsiflexion as the stairs are ascended. Of note, typically invention10may not actually provide active push off during ambulation, but rather, on each step, providing the optimal keel12angle to enhance push off characteristics during gait. Thus, invention10generally allows for the greatest anterior support and energy return per walking speed and environment.

In going up stairs, biomechanically, active push off is achieved with gastrocnemious muscle activity. It is contemplated that invention10may be modified within the scope of the claims and description such that a generally heavier design with increased power output consumption may generally simulate the natural muscle activity in this action. It is further understood that in ascending stairs, the foot naturally goes into dorsiflexion for the first half of the ascent. A separate setting may also be included or programmed whereas the user may place the invention10in “stair ascent” mode to allow slight plantarflexion or, if preferred, less dorsiflexion.

Going Down Stairs

It is contemplated that if heel sensor174load or strike sensor192is greater than zero two steps or times in a row and no toe sensor176load or strike is observed, resistance in MR fluid94may increase at foot flat position208angle to prevent full plantarflexion and slipping off step. Still furthermore, as with the other ambulations generally described above, microprocessor unit172may be calibrated specifically for a user after a test run, sample, or base line is established of user performing the ambulation in an optimal manner. It is contemplated that by allowing the foot to plantarflex, invention10may improve ambulation in descending stairs.

OTHER PREFERRED EMBODIMENTS

Additionally, it is contemplated that invention10may be used in conjunction with myoelectric muscle contacts on the residual limb404for trans-tibial amputees and may provide greater control in ambulation. By example, at heel strike, tibialis anterior contraction may be used to determine the level of damper resistance of MR fluid94preventing or reducing too fast or too much plantarflexion. Also, increased gastrocnemeous contraction during midstance may initiate dorsiflexion resistance sooner to allow keel12to remain in increased plantarflexion from midstance to toe off, therefore increasing push off may be utilized in fast walking or running.

Furthermore, invention10maybe used in conjunction with an orthotic device for a user who has lost the ability to actively plantarflex and/or dorsiflex their natural foot. It is contemplated that invention10dampening system18, sensor system22, microprocessor unit172and/or other elements or combinations thereof device may be located on the medial and/or lateral side of an orthotic brace and would control plantarflexion and dorsiflexion in a similar manner as is described above. Still furthermore, dampening system18may be used prosthetically or orthotically to control and manage other joints such as knee, hip, elbow, and the like.

Still furthermore, it is contemplated to provide an energy return adjustable heel height prosthetic foot. In a preferred embodiment, a manual lock would control the dampening system18by use of a permanent magnet placed against MR fluid94via a switch to adjust heel height. It is contemplated that this embodiment would not necessarily require sensory feedback system22or microprocessor unit172but would use the dampening system18to manually lock the ankle joint assembly16at a given angle to provide a user adjustable varied heel height foot.

Furthermore, the dampening system18may be altered to be an ankle unit only, with no keel, in order to be attached to other keel designs, or prosthetic feet in general.

Accordingly, other implementations are within the scope of the following claims. Changes may be made in the combinations, operations, and arrangements of the various parts and elements described herein without departing from the spirit and scope of the invention.