Patent Description:
In the field of prosthetics, particularly prosthetic feet, it is desirable to provide a high level of functionality with reliable performance. Further, as each user is different, it is desirable to provide a prosthesis that can be adapted to the particular needs of each individual user.

<CIT> (which is seen as the closest prior art document) discloses a prosthetic foot with a base spring with a forefoot area and a heel area, a connecting means arranged above the base spring and used to fasten the prosthetic foot to a prosthesis, and a frontal support, at the upper end of which the connecting means is arranged and which, at its lower end, is secured on a torsion element that can twist about the longitudinal axis of the prosthetic foot, wherein the torsion element is designed as a leaf spring arrangement secured to the base spring at one end in the heel area or in the forefoot area.

<CIT> discloses a knee orthoses or prostheses that can be used to automatically, when it is appropriate, to initiate a stand-up sequence based on the position of the person's knee with respect to the person's ankle while the person is in a seated position. When the knee is moved to position that is forward of the ankle, at least one actuator of the orthosis or prosthesis is actuated to help raise the person from the seated position to a standing position.

Particularly in the area of prosthetic feet, it is desirable to provide a prosthesis that provides stability throughout the gait cycle and in other activities such as stance. Further, during movement it is often desirable for a prosthetic foot to absorb and return elastic energy, while having enhanced energy conservation during ambulation. Even further, it is desirable for a prosthetic foot to be adjustable to an individual who may have various weights, heights, stride lengths, etc., as well as for prosthetic foot designs to allow for a variable stiffness, depending on the activity level of the amputee.

In accordance with one embodiment, a prosthetic foot is provided having one or more flexible members between two or more joints (e.g., pivots) to provide improved control and stability during a stance phase of gait cycle (e.g., provide more movement during stance). In one embodiment, the prosthetic foot is purely a mechanical foot. In another embodiment the prosthetic foot can include an actuator. In some embodiments, the actuator can be an active actuator (e.g., an electric motor) that can be selectively actuated (e.g., via an electric controller) to impart mechanical motion to the prosthetic foot (e.g., to change the orientation of the prosthetic ankle during a swing phase of gait cycle to dorsiflexion and then to plantarflexion). In another embodiment, the actuator can be a passive actuator (e.g., resilient member, spring or stiff beam).

In another embodiment, a prosthetic foot is provided with a variable stiffness control, which allows the stiffness of the prosthetic foot to be adjusted for different types of gait. In some embodiments, the variable stiffness control is mechanically actuatable (e.g., actuated manually by a user) to vary the stiffness of one or more elastic elements of the prosthetic foot (e.g., by changing the length of a lever arm of an elastic element, or by varying a gap between adjacent elastic elements). In another embodiment, the variable stiffness control can be automatically or actively adjusted during ambulation by the user (e.g., automatic adjustment of a lever arm of an elastic element, or active varying of a gap between adjacent elastic elements), e.g., based on the activity level of the user or the phase of gait cycle. In some embodiments the variable stiffness control can be automatically adjusted based on a sensed parameter of gait (e.g., sensed with one or more sensors on the prosthetic device).

In still another embodiment, the prosthetic foot or device can include a housing or adapter (e.g., for coupling the prosthetic foot or device to another prosthetic component) with a mechanism that provides for flexible motion in one or more planes (e.g., sagittal, coronal, transverse) so as to allow motion of the housing or adapter in a medial-lateral, anterior-posterior, or torsional direction. In one embodiment, where the prosthetic device is a prosthetic foot, the housing or adapter can be located generally at a location associated with a natural human ankle, and provide for motion similar to that of a natural human ankle. In some embodiments, the mechanism can include one or more slots or openings in one or more surfaces of the housing or adapter (e.g., slots on medial and lateral surfaces of the housing or adapter), that movably receive one or more pins, axles or joint members that connect the housing or adapter with other components (e.g., elastic elements or foot plates) of the prosthetic foot.

In one embodiment, a prosthetic foot comprises an attachment member and two or more flexible members. The attachment member can include a connector configured to connect the attachment member to a user or another prosthetic device. The two or more flexible members can be rotatably attached to the attachment member by rotatable joints such that the flexible members can both rotate and flex relative to the attachment member when the prosthetic foot contacts the ground.

In another embodiment, a prosthetic foot can include an attachment member, two or more flexible members, and an adjustable fastening member. The attachment member can include a connector configured to connect the attachment member to a user or another prosthetic device. The two or more flexible members can attach to the attachment member. Further, the two or more flexible members can extend from the attachment member to a foot portion of the prosthetic foot and be substantially movable relative to each other along their lengths. The adjustable fastening member can be configured to fasten the two or more flexible members along the foot portion of the prosthetic foot. Further, fastening can be provided at a plurality of positions along the length of the two or more flexible members to change the flexibility and resistance of the two or more flexible members.

In further embodiments, a prosthetic foot can include an attachment member, two or more flexible members, and a variable stiffness control member. The attachment member can include a connector configured to connect the attachment member to a user or another prosthetic device. The two or more flexible members can attach to the attachment member and can extend from the attachment member to a foot portion of the prosthetic foot. The flexible members can be substantially movable relative to each other along their lengths. However, the variable stiffness control member can be configured to adjust a length of a lever arm of the two or more flexible members along the foot portion of the prosthetic foot. For example, the variable stiffness control member can limit the relative motion between the flexible members.

In further embodiments, a prosthetic foot can include one or more flexible foot plates, an attachment member, and a means for modifying the stiffness of the prosthetic foot. The one or more flexible foot plates can be configured to bend along their lengths. The attachment member can include a connector configured to connect the attachment member to a user or another prosthetic device. The means for modifying the stiffness of the prosthetic foot can change the bending length of one or more of the flexible foot plates either prior to or during use.

In further embodiments, a prosthetic foot can include one or more elastic elements and an attachment member. The one or more elastic elements can be configured to bend along their lengths. The attachment member can include a connector configured to connect the attachment member to a user or another prosthetic device. Further, the attachment adapter can be connected to the one or more elastic elements via at least two pivotable joints. At least one of the elastic elements can extend between the at least two pivotable joints.

These and other features, aspects, and advantages of the invention disclosed herein are described below with reference to the drawings of preferred embodiments, which are intended to illustrate and not to limit the invention. Additionally, from figure to figure, the same reference numerals have been used to designate the same components of an illustrated embodiment. The following is a brief description of each of the drawings.

<FIG> depict an embodiment of a prosthetic foot <NUM>. The prosthetic foot <NUM> can attach to a user or to another prosthetic device with an attachment member <NUM>. The attachment member <NUM> is depicted as including a first connection portion <NUM> shown as a pyramid connector. The pyramid connector can attach to a stump on a user, to another prosthetic device, or to any other appropriate object. Further, it will be understood that the first connection portion <NUM> can include attachment features other than a pyramid connector, such as a threaded hole or screw, a latch, a magnetic member, tube clamp, or other features.

The attachment member <NUM> according to the claimed invention additionally include second and third connection portions <NUM>, <NUM> (see <FIG>, <FIG>). The attachment member <NUM> serve to provide a rigid connection between the connection portions <NUM>, <NUM>, <NUM>. For example, the attachment member <NUM> can comprise a substantially rigid material such as aluminum, steel, titanium, other metals or metallic alloys, carbon fiber, composites, or substantially rigid plastics. However, in other embodiments the attachment member <NUM> can be configured to provide flexibility, potentially in multiple planes. Thus, in some embodiments the attachment member <NUM> can comprise a more flexible material or include flexible joints between separate components of the attachment member <NUM>. For example, in some embodiments the attachment member <NUM> can have a flexible connection with the first connection portion <NUM>, allowing for motion in the medial/lateral and/or anterior/posterior directions. Further, the connection may allow torsional flexibility with the first connection portion <NUM>. In other embodiments, as further described below, the attachment member <NUM> can have a flexible connection with one or both of the second and third connection portions <NUM>, <NUM>.

Further, in some embodiments the attachment member <NUM> include other features of a prosthetic foot such as sensors configured to measure, for example, the position and movement of the prosthetic foot, the position and movement of various joints and components on the prosthetic foot (such as the rotational position and movement at the connection portions <NUM>, <NUM> and an actuator <NUM>, as further discussed below), pressures and forces on various components of the prosthetic foot <NUM> (such as on the attachment member <NUM>, the actuator <NUM>, or the elastic members <NUM>, <NUM>, <NUM>, further discussed below), and other measurable characteristics of the prosthetic foot. The sensors can additionally be configured to measure the prosthetic foot's environment, such as a terrain on which the prosthetic foot <NUM> moves. It will be understood that these sensors can be positioned on other elements of the prosthetic foot <NUM>, such as the actuator <NUM>, the elastic members <NUM>, <NUM>, <NUM>, and other elements, further described below.

The attachment member <NUM> can also include electronics (e.g., computer processor). For example, the attachment member <NUM> can include electronics configured to receive information from the sensors, discussed above. Further, in some embodiments, the attachment member <NUM> can include electronics configured to communicate information (e.g., information from the sensors) to other electronic devices, such as to other prosthetic devices or to an external computer (e.g., via wired or wireless communication, such as RF communication). Such electronics may also be configured to receive information from other prosthetic devices or an external computer, such information potentially including information from other sensors and/or operational commands for the prosthetic foot <NUM>.

The attachment member <NUM> can additionally include or define a cover <NUM>. The cover <NUM> can protect various components of the prosthetic foot <NUM> such as electronics (as described above), the actuator <NUM> (describe below), or other components. In some embodiments the cover <NUM> can include open portions in the coronal plane, allowing flexibility of motion in the medial-lateral directions. In further embodiments the cover <NUM> can include open portions in the sagittal plane, allowing flexibility of motion in the anterior-posterior directions. In some embodiments, the open portions can be vertical or horizontal slots formed in the cover <NUM>, to allow movement of pivot axles associated with any one of the connection portions <NUM>, <NUM>, <NUM>.

As shown in <FIG>, the attachment member <NUM> connect to a first elastic member <NUM> at the third connection portion <NUM>. The third connection portion <NUM> provides a rotatable connection, although non-rotatable connections can also be used. In some embodiments, the rotation can be provided by an axle firmly mounted to the attachment member <NUM>, about which the first elastic member <NUM> can rotate. In other embodiments, the first elastic member <NUM> is fixed to the axle, and relative rotation can be allowed between the axle and the attachment member <NUM>. In one embodiment, the first elastic member <NUM> can include or define a bushing or opening through which the axle extends. The first elastic member <NUM> can be formed from a sufficiently flexible material such as carbon fiber, though other suitable materials or combination of materials can be used (e.g., carbon and glass fibers). In other embodiments, the first elastic member <NUM> can be substantially inelastic, so as to provide a rigid connection. It will be understood that the other elastic members <NUM>, <NUM> (described further below) can be formed of similar materials and have similar connections as the first elastic member <NUM>.

Further, the first elastic member <NUM> can be formed into a shape configured to provide a desired flexibility or rigidity. As shown in <FIG>, the elastic member <NUM> includes a C-shaped portion <NUM> at an upper portion (proximal portion) of the first elastic member, near the third connection portion <NUM>. The C-shaped portion <NUM> is depicted as including an opening facing forward (e.g., the C-shaped portion <NUM> curves forwardly so that it is concave toward the front of the prosthetic foot), although in other embodiments the C-shaped portion can have an opening facing backward (e.g., the C-shaped portion can curve rearwardly so that it is concave toward the rear of the prosthetic foot). In some embodiments, the C-shaped portion <NUM> can bend more than <NUM> degrees, more than <NUM> degrees, <NUM> degrees, <NUM> degrees, or <NUM> degrees when unloaded. The bend of the C-shaped portion <NUM> can affect the resistance or flexibility of the first elastic member <NUM>. Notably, this resistance or flexibility can be adjusted, as described further below.

In the embodiment of <FIG>, the elastic member <NUM> extend from the lower portion of the C-shaped portion <NUM> into a foot portion <NUM>. The foot portion <NUM> of the elastic member <NUM> is substantially flat and extend from a rear portion of the prosthetic foot <NUM> toward a toe region of the prosthetic foot <NUM>. The foot portion <NUM> further includes a slit <NUM>. As shown, the slit <NUM> extends longitudinally to a toe end of the elastic member <NUM> to separate the foot portion <NUM> into two or more foot members that can flex independently, although in some embodiments the slit <NUM> can be closed at the toe end (e.g., where at least one of the elastic members <NUM>, <NUM>, <NUM> are solid at a toe portion such that the slit terminates prior to the end of the at least one elastic member). As will be discussed further below, the slit <NUM> can allow the flexibility and resistance of the elastic member <NUM> to be altered. In another embodiment, the elastic members <NUM>, <NUM>, <NUM> can be monolithic without any slits.

As further shown in <FIG>, the attachment member <NUM> connects to an actuator <NUM> at the second connection portion <NUM>. Like the third connection portion <NUM>, the second connection portion <NUM> can be rotatable or non-rotatable. Notably, in <FIG> the third connection portion <NUM> is in a front portion of the attachment member <NUM>, and the second connection portion <NUM> is in a rear portion of the attachment member <NUM>. Similarly, the actuator <NUM> is located at a rear portion of the prosthetic foot <NUM>. However, in other embodiments the actuator <NUM> can be positioned in a front portion of the prosthetic foot <NUM>, as further described below.

The actuator <NUM> can be in a variety of forms and can be operated in a variety of ways, as described by way of example in <CIT> as <CIT>, and <CIT>, published as <CIT>. For example, the actuator <NUM> can be a powered actuator such as a screw motor, or a passive member such as an elastic member (e.g., a spring) or a chamber with a magnetorheologic fluid, or can be a hydraulic or pneumatic system. Further, the actuator <NUM> can be configured to operate in a variety of ways, as also discussed in Appendices A and B. For example, the actuator <NUM> can be configured to extend or contract to assist a user during a gait cycle. For example, the actuator <NUM> can change the orientation of the prosthetic foot <NUM> to dorsiflexion and then to plantarflexion during a swing phase of gait cycle so that the toe portion of the prosthetic foot <NUM> is raised during the initial portion of swing phase. In another embodiment, the actuator <NUM> can change the orientation of the prosthetic foot <NUM> to plantarflexion when the user is in a relaxed (e.g., sitting) position. Further, such motion of the actuator <NUM> can change the flexibility or resistance of the elastic members <NUM>, <NUM>, <NUM>, as further described below. In some embodiments, the actuator <NUM> can also enter a low power mode (e.g., hibernation mode), such as a relaxed mode or an inactive mode. For example, the actuator <NUM> may enter a low power mode during stance, as the embodiments described herein can provide greater stability during stance, as further described below. Advantageously, the low power mode allows for the conservation of battery power used to power the actuator <NUM>, allowing the actuator <NUM> to be operated for longer periods of time between battery charging.

The actuator <NUM> is depicted as connecting to a second elastic member <NUM> at a fourth connection portion <NUM>. Like the second and third connection portions <NUM>, <NUM>, the fourth connection portion <NUM> can be rotatable or non-rotatable. In one embodiment, the second elastic member <NUM> can include or define a bushing or opening through which an axle extends to provide a rotatable connection or pivot axis between the second elastic member <NUM> and the actuator <NUM>. The second elastic member <NUM> extends into a foot portion in a manner similar to the foot portion <NUM> of the first elastic member <NUM>. In one embodiment, the second elastic member <NUM> extends to a distal end of the prosthetic foot <NUM>, so that the first and second elastic members <NUM>, <NUM> extend to generally the same location at the distal end of the prosthetic foot <NUM>. Further, the second elastic member <NUM> can include a slit similar to the slit <NUM> of the first elastic member <NUM>. Even further, the second elastic member <NUM> can be composed of materials similar to those for the first elastic member, such as carbon fiber. As shown, the second elastic member <NUM> is disposed below the first elastic member <NUM>, and extends tangentially forward and toward the first elastic member to abut the first elastic member <NUM> along the foot portion <NUM> of the first elastic member <NUM>. Although the first and second elastic members <NUM>, <NUM> are depicted as ending at approximately the same point at a toe portion of the prosthetic foot, in some embodiments the first elastic member <NUM> may extend further, or the second elastic member <NUM> may extend further. For example, as depicted in <FIG>, the first and third elastic members <NUM>, <NUM> can extend further than the second elastic member <NUM>, creating a gap between the first and third elastic members <NUM>, <NUM>. In other embodiments, a gap can be provided between the first and second elastic members <NUM>, <NUM> in a toe region of the prosthetic foot, as shown in <FIG>. As a further example, as depicted in, for example, <FIG> the third elastic member <NUM> (e.g., member 50A, described below) can end before a toe portion of the prosthetic foot <NUM>, such as at a metatarsal region of the foot. The first and/or second elastic members <NUM>, <NUM> (e.g., only second elastic member 40A in <FIG>) can then extend past the third elastic member <NUM> to the toe portion.

The prosthetic foot <NUM> can further include a third elastic member <NUM>. As shown, the third elastic member <NUM> can extend from a heel portion <NUM> (e.g., a cantilevered or free end) at a bottom and rear portion of the prosthetic foot <NUM>. This heel portion <NUM>, as shown, can be spaced from the actuator <NUM> and the second elastic member <NUM>, curving downward toward and away from the actuator <NUM>. From the heel portion <NUM>, the third elastic member <NUM> can extend to a toe portion of the prosthetic foot <NUM>, and can generally abut the foot portion second elastic member <NUM>, as that member abuts the first elastic member <NUM>. Further, the third elastic member <NUM> can have a slit along this foot portion that generally matches the slits in the first and second elastic members <NUM>, <NUM>. Additionally, as shown, the third elastic member <NUM> can include a heel slit <NUM> in the heel portion <NUM> of the elastic member.

As shown in the figures, the slit <NUM> in the first elastic member <NUM> can align with the slit in the second elastic member <NUM> and the slit <NUM> in the third elastic member <NUM> in the foot portion <NUM>. In one embodiment, the prosthetic foot <NUM> can have a stiffness control member <NUM> that can be actuated to vary the stiffness of the prosthetic foot. In some embodiments, the stiffness control member <NUM> can be a fastening member <NUM> (e.g., bolt and nut, clamp, staple, rivet, etc.) that couples two or more of the elastic members <NUM>, <NUM>, <NUM> to each other, where the fastening member <NUM> can travel along the slit <NUM> or a slot defined at least partially by the slit, best shown in <FIG>, or travel along a slot in the elastic members <NUM>, <NUM>, <NUM> where the elastic members do not have a slit. Attachment can be provided between the elastic elements <NUM>, <NUM>, <NUM>, for example, generally in a metatarsal region of the prosthetic foot <NUM>. Advantageously, in some embodiments the fastening member's <NUM> position can be adjustable along the length of the slit <NUM>. For example, when the fastening member <NUM> is a bolt and nut, the bolt can be moved to any desired position along the slit <NUM> and then fastened into place by tightening the nut. In some embodiments, an undercut or recess in the elastic members <NUM>, <NUM>, <NUM> can be provided to prevent the bolt and nut from protruding outwards. Notably, the position of the fastening member along the slit <NUM> can alter the flexibility and resistance of the elastic members <NUM>, <NUM>, <NUM>. Where the elastic members <NUM>, <NUM>, <NUM> are not held together (e.g., by the fastening member) they can separate and act as distinct elastic members instead of combining into a single elastic member where held together. Thus, if the fastening member <NUM> is moved forward, the elastic members <NUM>, <NUM>, <NUM> are held together over a shorter range, allowing more separation between them, and thus greater flexibility (e.g., the lever arm of the second elastic member <NUM> is relatively longer, resulting in greater flexibility of the prosthetic foot <NUM>). Alternatively, if the fastening member is moved rearward, the elastic members <NUM>, <NUM>, <NUM> are held together over a longer range, reducing the allowed separation and flexibility (e.g., the lever arm of the second elastic member <NUM> is relatively shorter, resulting in increased stiffness of the prosthetic foot <NUM>). Advantageously, the fastening member <NUM> can be adjusted to vary the stiffness of the prosthetic foot <NUM>.

In some embodiments, the stiffness control member <NUM> can be mechanically actuated, either manually by the user or automatically (e.g., actively adjusted) during ambulation by the user (e.g., based on the activity level of the user or the phase of gait cycle).

Notably, as discussed above, in some embodiments, the flexibility and resistance of the elastic members <NUM>, <NUM>, <NUM> can also be altered by the actuator <NUM> (independently of, or in combination with, the stiffness control member <NUM>). Thus, it will be understood that the flexibility and resistance of the elastic members <NUM>, <NUM>, <NUM> can be altered manually and/or by an actuator. In further examples, the stiffness control member <NUM> can be moved (e.g., automatically moved) by an actuator to adjust the resistance and flexibility of the elastic members <NUM>, <NUM>, <NUM>.

In some embodiments, it may be preferable to adjust the flexibility and resistance of the elastic members <NUM>, <NUM>, <NUM> to reduce resistance and increase flexibility while moving on level ground. Thus, for example, the stiffness control member <NUM> can be moved forward while ambulating on level ground to provide faster plantarflexion after heel strike. During other gait patterns, such as walking downstairs, one can reduce flexibility and increase resistance by moving the stiffness control member <NUM> backward. In some embodiments, these gait patterns can be detected by sensors and processors provided on or in communication with the prosthetic foot <NUM>. An actuator can then be controlled to adjust the flexibility and resistance of the elastic members <NUM>, <NUM>, <NUM> according to the detected gait pattern.

Variations to the embodiment in <FIG> are possible. For example, in the depicted embodiment a stiffness control member <NUM> (e.g., fastening member <NUM>) can be moved to various positions along the slit <NUM>, such that the resistance and flexibility of the elastic members <NUM>, <NUM>, <NUM> can be varied. However, in other embodiments it may be preferable to remove the slit <NUM> such that the elastic members <NUM>, <NUM>, <NUM> are more solid and provide a more uniform resistance. Further, in some embodiments it may be preferable to bond the elastic elements <NUM>, <NUM>, <NUM> in another manner, such as with an adhesive, so they remain permanently attached. The elastic elements <NUM>, <NUM>, <NUM> can also be held together with additional fastening members <NUM>, depicted as nuts and bolts in <FIG>, in addition to the adjustable fastening member <NUM>. In other embodiments, one or more of the elastic elements <NUM>, <NUM>, <NUM> can be formed together into a single piece. For example, in some embodiments the second and third elastic members <NUM>, <NUM> can be formed as a single piece.

In further embodiments this resistance can be varied by other methods. For example, in some embodiments the stiffness control member can be a wedge or insert that can be inserted where two or more of the elastic members <NUM>, <NUM>, <NUM> meet. For example, a wedge can be inserted between the first and second elastic members <NUM>, <NUM> (e.g., above the second and below the first). Similarly, a wedge can be inserted between the second and third elastic members <NUM>, <NUM>, such as at a wedging location <NUM>, depicted in <FIG>. The wedge can limit the range of motion of the elastic members <NUM>, <NUM>, <NUM> relative to each other, thus increasing their resistance. The size and shape of the wedge can be chosen to cause a particular desired resistance. Further, the wedge can be moved forward or rearward to vary the flexibility and resistance between the elastic members <NUM>, <NUM>, <NUM>.

The depicted embodiment also combines three separate elastic elements <NUM>, <NUM>, <NUM> that each provide a separate function. For example, the first elastic element <NUM> acts as a spring in parallel with the actuator <NUM>. Further, the second elastic element <NUM> acts as a spring in series with the actuator <NUM>. Both elastic elements <NUM>, <NUM> can thus be configured to work with or against the actuator <NUM> at different phases of the gait cycle. Further, the elastic elements <NUM>, <NUM> can be loaded or unloaded by the actuator <NUM>. Providing one spring in parallel and the other in series allows each spring to have a different effect on the dynamics of the prosthetic foot <NUM> during movement. For example, during heel strike, the actuator <NUM> and second elastic member <NUM> can act in series to provide the prosthetic foot <NUM> with a certain level of flexibility in addition to the energy stored by the third elastic member (e.g., be relatively less stiff at heel-strike), while during toe-off, the actuator <NUM> and first elastic element <NUM> can act in parallel to provide the prosthetic foot with a different level of flexibility (e.g., be relatively more stiff at toe-off). Thus, the independent flexibility and resistance of the elastic elements <NUM>, <NUM> can be chosen separately to optimize the behavior of the prosthetic foot <NUM>.

Notably, in the depicted embodiment the first and second elastic members <NUM>, <NUM> both extend toward the toe along the foot portion <NUM>. However, they do not extend toward the heel of the prosthetic foot <NUM>. The third elastic member <NUM> includes a heel portion <NUM>. The heel portion <NUM> thus provides flexibility and resistance to the prosthetic foot <NUM> during heel strike. This response during heel strike can be determined independently of a flexibility and resistance during toe-strike or toe-off during a gait cycle, as the third elastic element <NUM> is a separate piece from the first and second elastic elements <NUM>, <NUM>. Thus, for example, a system of separate elastic members <NUM>, <NUM>, <NUM> can include versions of each elastic member with varying flexibilities and resistances. One can then choose each elastic member <NUM>, <NUM>, <NUM> to provide a desired flexibility and resistance at different times during a gait cycle, depending on the needs of a particular user.

In further embodiments, the actuator <NUM> can be removed or replaced with a rigid member. For example, in some embodiments the second elastic member <NUM> can connect directly to the second connection portion <NUM>. In such embodiments, the first and second elastic members <NUM>, <NUM> can both be rotatably connected to the attachment member <NUM>. Further, in embodiments where the second elastic member <NUM> does not connect directly to the second connection portion <NUM>, it can still rotatably connect to an intermediary member (such as a rigid member replacing the actuator <NUM>) at a fourth connection portion <NUM> (as described above). In such embodiments, the three rotatable connections <NUM>, <NUM>, <NUM> can form a triangle with at least one elastic portion, the elastic portion being both the first and second elastic members <NUM>, <NUM>, between the fourth connection portion <NUM> and the third connection portion <NUM>.

The rotatable connections <NUM>, <NUM>, <NUM> with the elastic members <NUM>, <NUM> can provide a flexible resistance to rotation of the attachment member <NUM>. Advantageously, the use of both first and second elastic members <NUM>, <NUM> can provide for a natural rocking motion during stance that can provide improved stability with the prosthetic foot <NUM>. This stability can also be provided in embodiments that include an actuator <NUM>, e.g., when the actuator <NUM> is locked in a particular position or is substantially inactive.

<FIG> depict a second embodiment of a prosthetic foot 1A. It will be understood that the prosthetic foot 1A in these figures has features similar to the prosthetic foot <NUM> described above, and thus will be described in terms of its differences. As shown, the prosthetic foot 1A includes a first elastic member 30A having a C-shaped portion 32A, similar to that in the previously described embodiments. However, in the present embodiment the C-shape portion 32A can be reversed to have an opening facing rearward (e.g., the C-shaped portion 32A has a concave shape facing toward the rear of the prosthetic foot <NUM>). Further, as shown, the first elastic member 30A can include two parallel elastic pieces. Additionally, as shown, the first elastic member 30A can attach to the attachment member 10A at a second connection portion 16A that is non-rotatable, although in other embodiments the second connection portion 16A can be rotatable (e.g., via a pivot location, as shown in previous embodiments). Further, as shown, the first elastic member 30A can be shortened to not include a foot portion, like the foot portion <NUM> in the previous embodiments. Instead, the first elastic member 30A can attach to a fifth connection body 38A, also via a non-rotatable connection. However, the fifth connection body 38A can provide a rotatable connection to the second elastic member 40A, as shown in the figures, via a supplemental connection body 39A that can be considered to be part of the fifth connection body 38A.

Notably, the features in the embodiment in <FIG> also form a triangle with at least one elastic portion and three rotatable connections, similar to that discussed above in the previous embodiment. For example, as best shown in <FIG>, the prosthetic foot 1A includes a second connection portion 14A between the attachment member 10A and the actuator 20A. The actuator 20A can include a fourth connection portion 22A, connecting to the second elastic member 40A. The second elastic member 40A can connect to the first elastic member 30A with fifth connection body 59A. The first elastic member 30A can attach to the attachment member 10A, completing the triangle. In some embodiments, only one portion of the triangle can have an elastic portion. For example, in some embodiments the second elastic member 40A can be an inelastic or rigid member.

Further, in some embodiments the C-shaped portion 32A can be substantially similar to that shown in <FIG>, but include an additional elastic member 66A generally aligned with the C-shaped portion 32A, as best shown in <FIG>. The additional elastic member 66A can connect to the attachment member 10A in a manner similar to the first elastic member 30A. The additional elastic member 66A can then extend tangent with the first elastic member 30A along the C-shaped portion 32A and terminate at a free end unattached to the fifth connection body 39A. A stiffness control member similar to the stiffness control member <NUM> can then be provided between the C-shaped portion 32A and the additional elastic member 66A. For example, slits can be provided in the C-shaped portion 32A and the additional elastic member 66A to receive a fastening member that can be moved along the length of the slit to adjust the flexibility and resistance of the C-shaped portion 32A, as illustrated. In further embodiments, such adjustability of the flexibility and resistance of the elastic members 30A, 40A, 50A can be provided with other suitable mechanisms. For example, in some embodiments the fifth connection body 38A (including the supplemental connection body 39A) can be movable in an anterior-posterior direction along the second elastic member 40A to change the location of the fifth connection body 38A on the second elastic member 40A. For example, in some embodiments the second elastic member 40A can include a slot that can receive a fastener to fasten the fifth connection body 38A in place along the second elastic member. However, other suitable mechanisms can be used to adjust the location of the fifth connection body 38A relative to the second elastic member 40A (e.g., a track and worm gear arrangement).

Additionally, the depicted prosthetic foot 1A depicts an alternative method for attaching the second and third elastic members 40A, 50A. As shown, these members can be attached by two bolts 62A, on opposite sides of the slit 36A. However, it will be understood that other attachment methods can be used, such as those described above. Further, an adjustable fastening member can be provided in the slit 36A, as discussed above, to vary the flexibility and resistance of the prosthetic foot 1A.

<FIG> depict yet another embodiment of a prosthetic foot 1B. It will again be understood that the prosthetic foot 1B in these figures has features similar to the prosthetic foot <NUM> described above, and thus will be described in terms of its differences. As shown, the prosthetic foot 1B provides a design with the actuator 20B in a forward portion of the prosthetic foot. As shown, the attachment member 10B can still attach to the first elastic element 30B at a rotatable third connection portion 16B. However, the third connection portion 16B can be provided at an upper rear portion of the attachment member 10B. The second connection portion 14B can connect to the actuator 20B at a lower forward portion of the attachment portion 10B. The actuator 20B can then extend upwards from the second connection portion 14B to attach to the second elastic member 40B. The second elastic member 40B can then form a C-shaped portion that follows the forward-facing C-shaped portion 32B in the first elastic member 30B.

Connection of the third elastic member 50B is depicted as being substantially similar to the third elastic member 50A depicted in <FIG>. Similar variations can also be provided, as discussed above. Further, as shown, the first elastic member 30B can extend to a foot portion 34A and attach to the second and third elastic members 40B, 50B by the same bolts 62B. Further, as shown, the second elastic member 40B can extend beyond the first and second elastic members 30B, 50B, to a toe portion of the prosthetic foot 1B.

Notably, the features in the embodiment in <FIG> also form a triangle with at least one elastic portion and three rotatable connections, similar to that discussed above in the previous embodiments. For example, as best shown in <FIG>, the prosthetic foot 1B includes a second connection portion 14B between the attachment member 10B and the actuator 20B. The actuator 20B can include a fourth connection portion 22B, connecting to the second elastic member 40B. The second elastic member 40A can come to abut the first elastic member 30B, as described above regarding the previous embodiments. The first elastic member 30B can attach to the attachment member 10B at the third connection portion 16B, completing the triangle.

Further, as best shown in <FIG>, the first and second elastic members 30B, 40B can be connected by a stiffness control member 60B. In the illustrated embodiment, the stiffness control member 60B is an adjustable fastening member 60B and can allow for varied resistance and flexibility in a manner similar to that in the embodiments discussed above. In the present embodiment, the adjustable fastening member 60B is provided between only the first and second elastic members 30B, 40B (and not the third elastic member 50B), and in a rear portion of the prosthetic foot 1B. Moving the adjustable fastening member 60B downward and forward results in a lever arm of the first and second elastic members 30B, 40B between the fastening member 60B and the attachment member 10B that is relatively longer, resulting in increased flexibility of the prosthetic foot 1B. Alternatively, moving the adjustable fastening member 60B upward results in a lever arm of the first and second elastic members 30B, 40B between the fastening member 60B and the attachment member 10B that is relatively shorter, resulting in increased stiffness of the prosthetic foot 1B.

Claim 1:
A prosthetic foot comprising:
an attachment member (<NUM>, 10A, 10B) comprising:
a first connection portion (<NUM>, 12A, 12B) configured to attach to a stump on a user or another prosthetic device;
a second connection portion (<NUM>, 14A, 14B) in a rear portion of the attachment member (<NUM>, 10A, 10B);
a third connection portion (<NUM>, 16A, 16B) in a front portion of the attachment member (<NUM>, 10A, 10B);
a first elastic member (<NUM>, 30A, 30B) connected to the attachment member (<NUM>, 10A, 10B) at the third connection portion (<NUM>, 16A, 16B); and
an actuator (<NUM>, 20A, 20B) connected to the attachment member (<NUM>, 10A, 10B) at the second connection portion (<NUM>, 14A, 14B),
characterized in
that a second elastic member (<NUM>, 40A, 40B) is connected to the actuator (<NUM>, 20A, 20B) at a fourth connection portion (<NUM>, 22A, 22B), the third connection portion providing a rotatable connection, wherein the second elastic member is disposed below the first elastic member (<NUM>, 30A, 30B) characterised in that the third connection portion provides a rotatable connection between the attachment member and the first elastic member.