Patent Description:
Prosthetic digits are useful for amputees missing natural fingers. Existing solutions to prosthetic digits do not sufficiently mimic natural fingers and so functionality is not fully restored. Improvements to prosthetic digits are therefore desirable.

The embodiments disclosed herein each have several aspects no single one of which is solely responsible for the disclosure's desirable attributes. Without limiting the scope of this disclosure, its more prominent features will now be briefly discussed. After considering this discussion, and particularly after reading the section entitled "Detailed Description," one will understand how the features of the embodiments described herein provide advantages over existing systems, devices and methods for prosthetic digits.

The following disclosure describes non-limiting examples of some embodiments. For instance, other embodiments of the disclosed systems and methods may or may not include the features described herein. Moreover, disclosed advantages and benefits can apply only to certain embodiments of the invention and should not be used to limit the disclosure.

Features for prosthetic digits are described. The digits mimic natural fingers by having three articulating segments, including a proximal, middle and distal segment. The segments are articulated by an actuator and mechanical links configured to cause rotation of the segments. The digit may have multiple degrees of freedom. A single actuator may be used for a single digit. A tendon may be used in some versions. The rotated digit may provide articulation that mimics a natural finger and thus fully surrounds a variety of shapes and sizes of objects to provide and restore enhanced gripping functionality to amputees. The digit provides space, weight and power savings due to the need for only a single actuator. A spring-biased worm wheel transmission provides a manual mode for rotation of the digit and prevents damage due to rotation induced by external forces acting on the digit.

In one aspect, a prosthetic digit is described. The prosthetic digit comprises a mount, a proximal segment, a middle segment, a distal segment, a proximal link, a distal link, and an actuator. The mount is configured to attach to a hand. The proximal segment is rotatably attached to the mount at a first pivot, and the middle segment is rotatably attached to the proximal and distal segments. The proximal link is rotatably attached to the mount and rotatably attached to the middle segment at a second pivot. The distal link is rotatably attached to the proximal link and rotatably attached to the distal segment at a third pivot. The actuator is coupled with the mount and the proximal segment, and the actuator is configured to cause the proximal segment to rotate about the first pivot, where rotation of the proximal segment about the first pivot causes the middle and distal segments to rotate.

In another aspect, a prosthetic digit is described. The prosthetic digit comprises a mount, a plurality of articulating segments comprising a proximal articulating segment, and an actuator. The mount is configured to attach to a hand. The proximal segment is rotatably attached to the mount at a first pivot and is rotatably attached to the actuator at a first joint. The first joint is located offset from the first pivot, such that linear actuation output by the actuator imposes a force at the first joint to cause the proximal segment to rotate about the first pivot.

In another aspect, a prosthetic hand is described that includes the prosthetic digit.

In another aspect, a prosthetic digit is described that comprises a mount, a proximal segment, a middle segment, a distal segment, a proximal expandable link, and an actuator. The mount is configured to attach to a hand. The proximal segment is rotatably attached to the mount, and the middle segment is rotatably attached to the proximal and distal segments. The proximal expandable link is rotatably coupled with the mount and configured to expand linearly such that the middle and distal segments can rotate independently of rotation of the proximal segment. The actuator is in mechanical communication with the middle and distal segments and configured to cause the middle and distal segments to rotate. In some embodiments, the actuator is in mechanical communication with the proximal segment via a tendon.

In some embodiments, the prosthetic digit further comprises a distal link rotatably coupled with the proximal expandable link and with the distal segment.

In some embodiments, the proximal expandable link comprises a proximal portion, a distal portion, and a spring, where the proximal portion is in mechanical communication with the distal portion via the spring.

In another aspect, a prosthetic digit is described that comprises a mount, a plurality of articulating segments, and an actuator. The mount is configured to attach to a hand. The plurality of articulating segments comprise a proximal articulating segment. The proximal segment is rotatably attached to the mount at a first pivot, the proximal segment is rotatably attached to the actuator at a first joint, and the first joint is located offset from the first pivot, such that linear actuation output by the actuator imposes a force at the first joint to cause the proximal segment to rotate about the first pivot.

The foregoing and other features of the present disclosure will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. Understanding that these drawings depict only several embodiments in accordance with the disclosure and are not to be considered limiting of its scope, the disclosure will be described with additional specificity and detail through use of the accompanying drawings. In the following detailed description, reference is made to the accompanying drawings, which form a part hereof. In the drawings, similar symbols typically identify similar components, unless context dictates otherwise. The illustrative embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the scope of the subject matter presented here. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the drawing, can be arranged, substituted, combined, and designed in a wide variety of different configurations, all of which are explicitly contemplated and make part of this disclosure.

The following detailed description is directed to certain specific embodiments of the development. In this description, reference is made to the drawings wherein like parts or steps may be designated with like numerals throughout for clarity. Reference in this specification to "one embodiment," "an embodiment," or "in some embodiments" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of the phrases "one embodiment," "an embodiment," or "in some embodiments" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments necessarily mutually exclusive of other embodiments. Similarly, various requirements are described which may be requirements for some embodiments but may not be requirements for other embodiments.

Features for prosthetic digits are described. The digits mimic natural fingers by having three articulating segments, including a proximal, middle and distal segment. The segments are articulated by an actuator and rotatably connected mechanical links configured to contribute to and/or cause rotation of the digit segments. Some versions may use one or more tendons to apply opening and closing forces to the digit. Other version may not need a tendon to effect articulation of the segments. Rotation of a proximal segment causes rotation of the middle and distal segments via mechanical interaction of the links. There may be a proximal link and a distal link. The digit may have an actuator that outputs linear actuation to cause rotation of the proximal segment and/or proximal link. The actuator may linearly translate a housing that is rotatably connected to the proximal segment at a joint. The housing pushes on the proximal segment at the joint to create a torque on the segment about an offset pivot. The pivot may be a pin attaching the proximal segment to the proximal link. The pivot is at a location offset from the joint. In some embodiments, the proximal link may be linearly expandable and retractable to allow for variable relative rotational positions of the digit segments. The distal digit segment may rotate independent of rotation of the proximal digit segment. The digit may thus have multiple degrees of freedom with only a single actuator. The rotated digit may provide articulation that mimics a natural finger and thus fully surrounds both small and large objects to provide and restore enhanced gripping functionality to amputees. The digit provides space, weight and power savings due to the need for only a single actuator. The segments may provide movement similar to movement of respective human phalanges in sound natural fingers. In some embodiments, the digit includes transmission features for a worm wheel rotation by a lead screw. A keyed member such as a central axle is spring-biased and transmits rotation from the worm wheel to the digit while allowing for manual rotation of the digit without damaging the worm wheel or other components.

<FIG> are side and front views, respectively, of a lower arm prosthetic system <NUM> including a lower arm stump <NUM> having four prosthetic digits <NUM> and a prosthetic thumb <NUM> attached to the stump <NUM>. <FIG> is a side view of the system <NUM>. <FIG> is a front or palm-side view of the system <NUM>. The prosthetic digits <NUM> and/or thumb <NUM> may be any of the prosthetic digits described herein. The digits <NUM> may be connected to the end of the lower arm stump <NUM>, as shown in <FIG>, or to a residual natural palm <NUM>, as shown in <FIG>.

As shown in <FIG>, the digits <NUM> and thumb <NUM> are grasping an object <NUM>, shown as a round object such as a can or ball. The digits <NUM> are surrounding the object <NUM> such that the object <NUM> may be held securely by the system <NUM>. The rotatable capability of the segments of the digits <NUM> allows for this secure grasp. The shape of the object <NUM> has a width and contour that allows the articulating digits <NUM> to provide a secure grasp. The digits <NUM> have various articulating segments that may rotate at various angles with respect to the adjacent segment. In some embodiments, the segments may rotate accordingly to a fixed angular relation, such that only certain sizes and shapes of objects <NUM> may be securely grasped. In some embodiments, the segments may rotate accordingly to a variable angular relation, such that only different sizes and shapes of objects <NUM> may be securely grasped.

<FIG> are back and front views, respectively, of a prosthetic hand <NUM> incorporating embodiments of prosthetic digits <NUM> and a prosthetic thumb <NUM>. The hand <NUM> has a palm portion <NUM> attached to proximal ends of the digits <NUM> and thumb <NUM>. The hand <NUM> may have a wrist <NUM> that may rotate, which may allow for rotation of the palm portion <NUM>, and the digits <NUM> and thumb <NUM> attached thereto, about a longitudinal axis defined by the wrist <NUM>. The prosthetic digits <NUM> may be any of the prosthetic digits described herein. The prosthetic digits <NUM> may rotate according to a fixed or variable angular relation among the articulating digit segments, as described with respect to the system <NUM> of <FIG>.

<FIG> are various views of an embodiment of a prosthetic digit <NUM>. The digit <NUM> may be used with the system <NUM> or hand <NUM>. The digit <NUM> includes an actuator <NUM>, a mount <NUM>, a proximal segment <NUM>, a middle segment <NUM>, and a distal segment <NUM>. The segments may articulate, for example rotate, relative to each other. The digit <NUM> includes mechanically-connected links, which may be rigid, as further described herein, for example with respect to <FIG>. The segments <NUM>, <NUM>, <NUM> may provide natural movement similar to that provided respectively by proximal, middle and distal phalanges of a sound natural finger.

The mount <NUM> and/or the actuator <NUM> may be connected with and/or located within, partially or completely, the arm stump <NUM>, the residual palm <NUM>, or the prosthetic palm <NUM>. The proximal segment <NUM> may rotate relative to the mount <NUM> and/or the actuator <NUM>. The middle segment <NUM> may rotate relative to the proximal segment <NUM>. The distal segment <NUM> may rotate relative to the middle segment <NUM>.

As shown in <FIG>, the actuator <NUM> includes a proximal end <NUM> and extends to a distal end <NUM>. The proximal end <NUM> may attach to a hand, palm, etc. The distal end <NUM> attaches to a proximal end <NUM> of the proximal segment <NUM>. The proximal segment <NUM> is rotatable relative to the actuator <NUM> about the joint <NUM>. The actuator <NUM> may apply a normal force to the proximal segment <NUM> at the joint <NUM> to cause the proximal segment <NUM> to pivot about an offset first pivot <NUM>, as further described herein. The proximal segment <NUM> extends from the proximal end <NUM> to a distal end <NUM>. The distal end <NUM> attaches to a proximal end <NUM> of the middle segment <NUM>. The middle segment <NUM> is rotatable relative to the proximal segment <NUM> about the joint <NUM>. The middle segment <NUM> extends from the proximal end <NUM> to a distal end <NUM>. The distal end <NUM> attaches to a proximal end <NUM> of the distal segment <NUM>. The distal segment <NUM> is rotatable relative to the middle segment <NUM> about the joint <NUM>. The rotatable connections at the joints <NUM>, <NUM>, <NUM> may include pin connections, hinges, and/or other suitable features for providing a rotatable engagement.

<FIG> is a cross-section view of the digit <NUM>, as taken along the line 3D-3D indicated in <FIG>. As shown in <FIG>, the digit <NUM> may include the actuator <NUM>. The actuator <NUM> may be a linear actuator. The actuator <NUM> produces or results in linear motion. As shown, the actuator <NUM> may include a motor <NUM> supplied with power from a battery, which may be in the hand or other location. A support <NUM>, such as a motor mount or other structure, may carry or otherwise support the actuator <NUM>. The support <NUM> may have an pin <NUM> or other suitable feature in a proximal end thereof to secure, for example rotatably attach, the support <NUM> with the mount <NUM>.

The actuator <NUM> includes a housing <NUM>. The housing <NUM> extends axially and defines a cavity <NUM> therein. The cavity <NUM> may be a cylindrical opening extending axially through the housing <NUM>. A proximal end of the housing <NUM> may be open to the cavity <NUM>. A distal end of the housing <NUM>, for example at the distal end <NUM> of the actuator <NUM>, connects with the proximal segment <NUM> at the joint <NUM>. The housing <NUM> translates axially to cause rotation of the proximal segment <NUM>, as further described herein.

The motor <NUM> may be supported, for example a fixed portion thereof, by the support <NUM>. There may be a bushing <NUM> rotationally supporting a rotating portion of the motor <NUM>, which may be located within and/or supported by the support <NUM>. The motor <NUM> may include a shaft <NUM> extending therefrom, for example extending distally therefrom, that is rotated about an axis along which the shaft <NUM> extends. A cap <NUM>, such as a nut, may attach to a distal end of the shaft <NUM>. A leadscrew <NUM> having external threads <NUM> thereon may be positioned about the shaft <NUM> and secured in place by the cap <NUM>. The leadscrew <NUM> may be a nut having external threads or other suitable features that engage corresponding internal structure of the housing <NUM> to translate the housing <NUM> back and forth.

The actuator <NUM> may output linear motion to cause rotation of the digit <NUM>, as further described. The motor <NUM> or other portions of the actuator <NUM> may use or provide rotary, linear, cyclic and/or other types of motion. As shown, the actuator <NUM> is in mechanical communication with the leadscrew <NUM> having external threads <NUM>. The actuator <NUM> rotates the leadscrew <NUM>. The external threads <NUM> of the leadscrew <NUM> are in mechanical communication with internal threads <NUM> of the housing <NUM>. The internal threads <NUM> may be located along the cavity <NUM> of the housing <NUM>. The housing <NUM> may move relative to the support <NUM>. The leadscrew <NUM> is rotated while remaining axially stationary to cause the housing <NUM> to translate axially along an axis defined by the cavity <NUM> via interaction of the external and internal threads <NUM>, <NUM>. The threaded engagement features and rotational motion of the actuator <NUM> is one example embodiment. Other features and/or actuator types may be used to output linear motion of the housing <NUM>.

As the housing <NUM> is advanced distally and proximally, the actuator <NUM> may rotate about the pin <NUM> to accommodate the rotating proximal segment <NUM>. For instance, the joint <NUM> may translate slightly during rotation, and the distal end of the housing <NUM> may move accordingly such that the actuator <NUM> rotates slightly at the pin <NUM>. The actuator <NUM> may rotate counterclockwise as oriented in <FIG> during a distal movement of the housing <NUM> for a closing rotational movement of the segments <NUM>, <NUM>, <NUM>. The actuator <NUM> may rotate clockwise as oriented in <FIG> during a proximal movement of the housing <NUM> for an opening rotational movement of the segments <NUM>, <NUM>, <NUM>. Other configurations of the digit <NUM> may result in opposite rotations of the actuator <NUM> during opening and closing of the segments <NUM>, <NUM>, <NUM>.

As further shown in <FIG>, the digit <NUM> includes a mount <NUM>, a proximal link <NUM>, and a distal link <NUM>. The mount <NUM> extends from a proximal end <NUM> to a distal end <NUM>. The proximal link <NUM> extends from a proximal end <NUM> to a distal end <NUM>. The distal link <NUM> extends from a proximal end <NUM> to a distal end <NUM>.

The proximal end <NUM> of the mount <NUM> may be attached to a proximal end of the actuator <NUM>, for example rotatably attached thereto. The mount <NUM>, such as at the proximal end <NUM> and/or other locations, may be attached to a hand, such as a prosthetic hand. Further details of the mount <NUM> are described herein, for example with respect to <FIG>. The distal end <NUM> of the mount <NUM> is rotatably attached to the proximal end <NUM> of the proximal link <NUM> about a connection <NUM>. The mount <NUM> is also rotatably attached to the proximal segment <NUM> of the digit <NUM> about a first pivot <NUM>. The first pivot <NUM> is located between the proximal and distal ends <NUM>, <NUM> of the mount <NUM>.

The proximal link <NUM> is rotatably attached to the middle segment <NUM> of the digit <NUM> about a second pivot <NUM>. The second pivot <NUM> is located between the proximal and distal ends <NUM>, <NUM> of the proximal link <NUM>. The proximal link <NUM> may include a dogleg, where the proximal end <NUM> extends along a first axis and the distal end <NUM> extends a long a second axis that is at an angle relative to the first axis. The second pivot <NUM> may be located at or near the vertex of the dogleg of the proximal link <NUM>. The distal end <NUM> of the proximal link <NUM> is rotatably attached to the proximal end <NUM> of the distal link <NUM> about a connection <NUM>. The distal end <NUM> of the distal link <NUM> is rotatably attached to the distal segment <NUM> of the digit <NUM> about a third pivot <NUM>.

In sum, the digit segments <NUM>, <NUM>, <NUM> are, respectively, rotatably attached to the links <NUM>, <NUM>, <NUM> at, respectively, the pivots <NUM>, <NUM>, <NUM>. The segments <NUM>, <NUM>, <NUM> are rotatably attached to each other at the joint <NUM>, which rotatably connects the proximal segment <NUM> to the middle segment <NUM>, and at the joint <NUM>, which rotatably connects the middle segment <NUM> to the distal segment <NUM>. The links <NUM>, <NUM>, <NUM> are rotatably attached to each other at the connection <NUM>, which rotatably connects the mount <NUM> to the proximal link <NUM>, and at the connection <NUM>, which rotatably connects the proximal link <NUM> to the distal link <NUM>.

All or some of the rotatable connections at the joints <NUM>, <NUM>, <NUM>, at the pivots <NUM>, <NUM>, <NUM>, and at the connections <NUM>, <NUM> may include pins, hinges, and/or other suitable features for providing a rotatable engagement. The axes of rotation for the joints <NUM>, <NUM>, <NUM>, pivots <NUM>, <NUM>, <NUM>, and connections <NUM>, <NUM> may be perpendicular to a longitudinal axis of the digit <NUM>. Such longitudinal axis may be defined by the fully extended digit <NUM>, for example as shown in <FIG>. The longitudinal axis may be defined by the direction of linear movement provided by the actuator <NUM>, for example the direction of linear movement of the leadscrew <NUM>. The rotation axes for the joints <NUM>, <NUM>, <NUM>, pivots <NUM>, <NUM>, <NUM>, and connections <NUM>, <NUM> may be parallel to each other. The locations of the joints <NUM>, <NUM>, <NUM>, pivots <NUM>, <NUM>, <NUM>, and connections <NUM>, <NUM> may change as the digit <NUM> rotates, for example some or all of these the locations may change relative to the support <NUM> and/or relative to the mount <NUM>.

<FIG> is a partially exploded perspective view of the prosthetic digit <NUM>. As shown, the mount <NUM> includes an elongated proximal portion <NUM> defining a cavity <NUM> therein. The proximal end <NUM> includes a proximal wall <NUM> having openings 302A extending therethrough. The pin <NUM> of the support <NUM> may extend through the openings 302A to rotatably connect the proximal ends of the actuator <NUM> and mount <NUM>. This allows the actuator <NUM> to rotate slightly at the proximal end as needed for digit actuation. The mount <NUM> includes a series of tabs 351A to connect the mount <NUM> to a hand, such as the prosthetic hand <NUM> or the palm <NUM>. The mount <NUM> may fixedly attach to the hand. There may be four tabs 351A as shown, or more or fewer than four. The mount <NUM> includes two distally extending forks <NUM>. The forks <NUM> extend from the distal end of the portion <NUM>. The forks <NUM> define a space therebetween that receives a proximal portion of the proximal segment <NUM>. The forks <NUM> include openings 357A that receive therein the pivot <NUM>. The pivot <NUM> is shown as a pin with rollers.

The mount <NUM> includes a prong 354A extending distally from the proximal end of the portion <NUM>. The prong 354A is located between the forks <NUM>. The prong 354A is at the proximal end <NUM> of the mount <NUM>. The prong 354A includes an opening 356A therethrough that receives therein a central portion of the pivot <NUM>. The pivot <NUM> may thus rotate within the openings 356A, 357A, and/or provide an axle about which the proximal segment <NUM> rotates. The prong 354A includes an opening 358A at a distal end thereof. The opening 358A receives therein the connection <NUM>, shown as a pin. The connection <NUM> may thus rotate within the openings 358A, and/or provide an axle about which the proximal link <NUM> rotates, as described herein.

The actuator <NUM> includes the joint <NUM>, shown as a pin. The joint <NUM> is received into openings 318A of the proximal segment <NUM>. The joint <NUM> may be a shear pin that is pushed by the housing <NUM> axially to impart a force on the proximal segment <NUM> at the openings 318A. The joint <NUM> is offset from the pivot <NUM>. Thus pushing on the joint <NUM> will create a torque on the proximal segment about the pivot <NUM>. The axes of rotation of the joint <NUM> and pivot <NUM> may be parallel to each other.

The middle segment <NUM> includes one or more openings 328A which receives the joint <NUM> therein. The joint <NUM> is shown as a pin. The joint <NUM> may thus rotate within the openings 328A, and/or provide an axle about which the proximal and middle segments <NUM>, <NUM> rotate, as described herein. The distal segment <NUM> includes one or more openings 338A which receives the joint <NUM> therein. The joint <NUM> is shown as a pin. The joint <NUM> may thus rotate within the openings 338A, and/or provide an axle about which the middle and distal segments <NUM>, <NUM> rotate, as described herein.

<FIG> are sequential views of the prosthetic digit <NUM> shown in various rotated configurations. "Distal" and "proximal" as used herein have their usual and ordinary meaning. For clarity, the "distal" and "proximal" directions are indicated in <FIG> for the fully extended digit <NUM>, and generally refer to a direction or portion of the digit <NUM> that is, respectively, farther from or closer to the proximal end <NUM> of the mount <NUM> along the length of the digit <NUM>. <FIG> shows an embodiment of a fully straightened digit <NUM>, <FIG> shows an embodiment of partially closed digit <NUM>, and <FIG> shows an embodiment of a fully closed digit <NUM>.

The middle and distal segments <NUM>, <NUM> may rotate as the proximal segment <NUM> rotates due to interaction of the mount <NUM> and links <NUM>, <NUM> as further described. As shown, for example in <FIG>, the distal segment <NUM> may completely close such that the distal segment <NUM> is parallel or near parallel with the proximal segment <NUM>. In some embodiments, the distal segment <NUM> may rotate through this parallel position such that at full rotation the distal segment <NUM> is angled back toward the middle segment <NUM>. The distal segment <NUM> may contact the proximal segment <NUM> in the fully rotated configuration. Such full or more complete closure of the distal segment <NUM> provides advantageous gripping capability with the digit <NUM> and more fully restores lost sound finger dexterity to a user, such as an amputee. The features described herein, such as the configuration and interaction of the mount <NUM>, links <NUM>, <NUM> and segments <NUM>, <NUM>, <NUM>, among other things, contribute to such advantages.

To cause rotation of the digit <NUM>, the actuator <NUM> may rotate the leadscrew <NUM> having the external thread. The external threads of the leadscrew <NUM> mechanically communicate with internal threads <NUM> of the housing <NUM>. The actuator <NUM> may rotate the leadscrew <NUM> in a first rotational direction to cause the housing <NUM> to move, for example to translate, distally relative to the leadscrew <NUM>. The leadscrew <NUM> may remain axially stationary. The housing <NUM> moves farther distally as shown sequentially from <FIG>. The direction of rotation of the digit <NUM> may be reversed (e.g., from <FIG> to <FIG>) by the actuator <NUM> rotating the leadscrew <NUM> in a second rotational direction, that is opposite to the first rotational direction, to cause the housing <NUM> to move, for example to translate, proximally relative to the leadscrew <NUM>.

Distal movement of the housing <NUM> causes the proximal end <NUM> of the proximal segment <NUM> to move distally via the rotatable connection at the joint <NUM>. Distal movement of the proximal segment <NUM> at the joint <NUM> will cause the proximal segment <NUM> to rotate clockwise (as oriented in the figures) about the first pivot <NUM> due to the offset locations of the joint <NUM> and the pivot <NUM>. A line of action of force is imparted on the proximal segment <NUM> that extends through the joint <NUM> and thus imparts a moment on the proximal segment <NUM> about the pivot <NUM>. The clockwise rotation of the proximal segment <NUM> about the first pivot <NUM> causes clockwise rotation of the proximal segment <NUM> relative to the housing <NUM> about the joint <NUM>. Thus, the proximal segment <NUM> rotates clockwise as shown sequentially viewed from <FIG>. To reverse the direction of rotation in the counterclockwise direction (as oriented in the figures), these movements may be reversed, where the housing <NUM> is moved proximally to cause the proximal end <NUM> of the proximal segment <NUM> to move proximally and rotate counterclockwise about the first pivot <NUM> and the joint <NUM>. A pinned or other type connection at the joint <NUM> as described herein may allow for such pushing and pulling forces by the housing <NUM> to be transferred to the proximal segment <NUM>.

As the proximal segment <NUM> rotates clockwise about the pivot <NUM>, the middle segment <NUM> also rotates clockwise with the rotating proximal segment <NUM> due to the connection of the two segments <NUM>, <NUM> at the joint <NUM>. In some embodiments, the middle segment <NUM> may be constrained from rotating farther in the counterclockwise direction, for instance the configuration shown in <FIG> may be the limit of rotation of the middle segment <NUM> relative to the proximal segment <NUM> about the joint <NUM>.

The rotation of the middle segment <NUM> also causes the distal segment <NUM> to rotate clockwise, due to the connection of the two segments <NUM>, <NUM> at the joint <NUM>. In some embodiments, the distal segment <NUM> may be constrained from rotating farther in the counterclockwise direction, for instance the configuration shown in <FIG> may be the limit of rotation of the distal segment <NUM> relative to the middle segment <NUM> about the joint <NUM>.

As the middle segment <NUM> rotates clockwise, the proximal link <NUM> also rotates clockwise due to the connection of the middle segment <NUM> and the proximal link <NUM> at the second pivot <NUM>. Further, the proximal link <NUM> is translationally constrained by the mount <NUM> at the rotatable connection <NUM>. The proximal link <NUM> thus rotates clockwise about the connection <NUM>. The joint <NUM> is offset from the second pivot <NUM> as shown. Thus a torque may be imposed on the middle segment <NUM> about the pivot <NUM>. The axes of rotation of the joint <NUM> and second pivot <NUM> may be parallel.

As the proximal link <NUM> rotates clockwise about the connection <NUM>, this also causes the distal link <NUM> to rotate clockwise due to the translational constraint between the proximal link <NUM> and the distal link <NUM> at the rotatable connection <NUM>. As the distal link <NUM> rotates clockwise, the distal segment <NUM> is translationally constrained by the distal link <NUM> at the third pivot <NUM>. The distal segment <NUM> also rotates relative to the middle segment <NUM> about the rotatable connection at the joint <NUM>. The joint <NUM> is offset from the third pivot <NUM> as shown. Thus a torque may be imposed on the distal segment <NUM> about the pivot <NUM>. The axes of rotation of the joint <NUM> and third pivot <NUM> may be parallel. The distal segment <NUM> thus rotates farther clockwise about the third pivot <NUM> to provide the closed configuration shown in <FIG>.

The digit <NUM> may be rotated in the counterclockwise direction sequentially from the configurations shown in <FIG> to <FIG>. The counterclockwise rotation operates in reverse as described above with respect to the clockwise rotation. For example, proximal movement of the proximal end <NUM> of the proximal segment <NUM> pulls proximally at the joint <NUM> and causes the proximal segment <NUM> to rotate counterclockwise about the pivot <NUM>, which causes the middle segment <NUM> and proximal link <NUM> to rotate counterclockwise respectively about the joint <NUM> and pivot <NUM>, which causes the distal segment <NUM> and distal link <NUM> to rotate counterclockwise respectively about the joint <NUM> and pivot <NUM>.

<FIG> are various views of another embodiment of a prosthetic digit <NUM>. The digit <NUM> may be used with the system <NUM> or hand <NUM>. The digit <NUM> includes a mount <NUM>, a proximal segment <NUM>, a middle segment <NUM>, and a distal segment <NUM>. The mount <NUM> and segments <NUM>, <NUM>, <NUM> may have the same or similar features and/or functions as the mount <NUM> and segments <NUM>, <NUM>, <NUM>, and thus may articulate, for example rotate, relative to each other. The digit <NUM> includes mechanically-connected rigid links including an expandable proximal link <NUM>, as further described herein, for example with respect to <FIG>.

The mount <NUM> and segments <NUM>, <NUM>, <NUM> may be rotatably attached at joints <NUM>, <NUM>, <NUM>, which may have the same or similar features and/or functions as the joints <NUM>, <NUM>, <NUM>, respectively. However, the mount <NUM> may not have a linearly translatable portion. The digit <NUM> may have an actuator <NUM>, which may have the same or similar features and/or functions as the actuator <NUM>, except as otherwise described.

<FIG> is a cross-section view of the digit <NUM>, as taken along the line 4D-4D indicated in <FIG>. As shown in <FIG>, the mount <NUM> may support the actuator <NUM>. The actuator <NUM> may include a housing <NUM> extending proximally. The housing <NUM> may be used to house features for rotation of the segments <NUM>, <NUM>, <NUM>, such as a spring <NUM> that provides a force in a proximal direction on a plunger <NUM> attached to a proximal end <NUM> of a return tendon <NUM>, as further described herein. Some embodiments may not include the return tendon <NUM>.

The actuator <NUM> may include a motor <NUM> supplied with power from a battery, which may be in the hand or other location. The motor <NUM> may be in mechanical communication with an output shaft <NUM> that extends, for example distally, therefrom. A worm gear <NUM> having external threads <NUM> thereon may be attached to the shaft <NUM>. Actuation of the motor <NUM> causes motion to be transmitted via a gearbox to the shaft <NUM> to rotate the worm gear <NUM>. The digit <NUM> may include a worm wheel <NUM> having external teeth <NUM> thereon. The threads <NUM> of the worm gear <NUM> contact the teeth <NUM> of the worm wheel <NUM> to cause rotational motion of the worm wheel <NUM>. The worm wheel <NUM> may be rotated a first rotational direction to cause a first rotation of the digit <NUM> in a first direction (e.g. to close the digit <NUM>). The worm wheel may have pulley features that attach to and wrapingly receive therearound a proximal end of an actuation tendon <NUM>, as further described. The worm wheel <NUM> may be rotated in a second rotational direction that is opposite the first rotational direction to allow for a second rotation of the digit <NUM> in a second direction that is opposite the first direction (e.g. to open the digit), which movement may be caused by the return tendon <NUM>, as further described. Some embodiments may not include the actuation tendon <NUM> or return tendon <NUM>.

The digit <NUM> includes an expandable proximal link <NUM>. The link <NUM> is attached to the worm wheel <NUM>. Rotation of the worm wheel <NUM> in a first rotational direction for a first angular amount causes a corresponding rotation of the link <NUM> in the first rotational direction for the first angular amount. The link <NUM> may expand. The link <NUM> or a portion thereof may extend distally relative to the worm wheel <NUM>. The link <NUM> includes a proximal end <NUM> and extends to a distal end <NUM>. The proximal end <NUM> includes a fixed portion <NUM>, such as a cylinder. The distal end <NUM> includes a housing <NUM>, such as a piston. The link <NUM> may include a spring <NUM>, such as an extension spring. Extension of the spring <NUM> beyond a neutral length may cause a restoring force that biases the spring back to a shorter length. The link <NUM> may expand as it is rotated to allow for multiple degrees of freedom rotation of the digit <NUM>. The housing <NUM> may expand distally relative to the fixed portion <NUM>. The spring <NUM> may bias the housing <NUM> in the proximal direction. The housing <NUM> may retract in the proximal direction relative to the fixed portion <NUM>. Further details of the link <NUM> are described herein, for example with respect to <FIG>.

The link <NUM> is attached to the middle segment <NUM> of the digit <NUM>. The distal end <NUM> of the link <NUM> may be rotatably attached to the middle segment <NUM> at the connection <NUM>. The middle segment <NUM> may include an ear <NUM> that rotatably connects with the link <NUM>. The connection <NUM> may include a pin or other feature that extends through the link <NUM> and ear <NUM> at the connection <NUM>. The link <NUM> may extend between two of the ears <NUM>, with one ear <NUM> on either lateral side of the distal end <NUM> of the link <NUM> at the connection <NUM>.

The digit <NUM> may include a distal link <NUM>. The distal link <NUM> extends from a proximal end <NUM> to a distal end <NUM>. The proximal end <NUM> may be rotatably attached to the ear <NUM> at a connection <NUM>. The ear <NUM> may include a rounded slot <NUM>. The connection <NUM> may include a pin or other feature that extends through the link <NUM> and rounded slot <NUM> at the connection <NUM>. The connection <NUM> allows the proximal end <NUM> of the distal link <NUM> to rotate within and move along the slot <NUM> as the digit <NUM> articulates, for example as the middle segment <NUM> rotates relative to the proximal segment <NUM> and/or as the distal segment <NUM> rotates relative to the middle segment <NUM>.

The distal link <NUM> is attached to the distal segment <NUM>. The distal end <NUM> of the distal link <NUM> may be rotatably attached to the distal segment <NUM> at the connection <NUM>. The connection <NUM> may include a pin or other feature that extends through the distal link <NUM> and distal segment <NUM> at the connection <NUM>. The distal segment <NUM> may include an ear <NUM> having an opening therethrough and with which the distal link <NUM> is attached. The distal end <NUM> of the link <NUM> may extend between two of the ears <NUM>, with one ear <NUM> on either lateral side of the distal end <NUM> of the link <NUM> at the connection <NUM>.

<FIG> are various views of the proximal expandable link <NUM>. <FIG> is a perspective view of the link <NUM>, <FIG> is a top view, <FIG> is a side view in an unexpanded configuration, <FIG> is a side view in an expanded configuration, and <FIG> is a cross-section view as taken along the line 5E-5E shown in <FIG>.

The proximal link <NUM> may include an extension <NUM>. There may be two extensions <NUM> extending proximally, for example forming a clevis type connection. The extensions <NUM> may each include an opening <NUM> therethrough. The extensions <NUM> may define a space <NUM> therebetween. The extensions <NUM> may laterally surround the worm wheel <NUM> when installed with the worm wheel <NUM> located in the space <NUM>, and a pin or other feature may extend through the openings <NUM> and a central opening of the worm wheel <NUM> to connect the link <NUM> with the worm wheel <NUM>.

The housing <NUM> may move linearly with respect to the fixed portion <NUM>. The fixed portion <NUM> may define a longitudinal axis along which the housing <NUM> may translate. A spring <NUM> may be located within the link <NUM>. As shown in <FIG>, a proximal end of the spring <NUM> may be located within the fixed portion <NUM> and be attached to a proximal end of the link <NUM>. A distal end of the spring <NUM> may attach to a proximal end of the housing <NUM>. In some embodiments, the spring <NUM> may extend through and attach to the housing <NUM>. <FIG> shows the link <NUM> expanded relative to the configuration in <FIG>. The expanded housing <NUM> will stretch the spring <NUM>. The spring <NUM> will exert a restoring force on the housing <NUM> and bias the housing proximally. The link <NUM> may then return to the configuration shown in <FIG>. The link <NUM> may repeatedly extend and retract as the finger is rotated to close the digit <NUM> and then rotated back to open the digit <NUM>. The link <NUM> may therefore expand during rotation of the digit <NUM>, as further described herein, for example with respect to <FIG>. In some embodiments, the link <NUM> may not expand during rotation of the digit <NUM> for added degrees of freedom, as further described herein, for example with respect to <FIG>.

<FIG> are sequential views of the prosthetic digit <NUM> shown in various rotated configurations. The sequential views illustrate an embodiment of the middle and distal segments <NUM>, <NUM> rotating as the proximal segment <NUM> also rotates. The rotation of the segments <NUM>, <NUM>, <NUM> may be due to the configuration and interaction of the mount <NUM>, segments <NUM>, <NUM>, <NUM> and links <NUM>, <NUM>.

The proximal segment <NUM> may rotate relative to the mount <NUM> about the joint <NUM> (see <FIG>). To initiate rotation of the digit <NUM>, the actuator <NUM> may cause the worm gear <NUM> to rotate and thereby rotate the worm wheel <NUM>.

In some embodiments, the link <NUM> may rotate with the rotating worm wheel <NUM>. The link <NUM> may rotate the same or similar angular amount as the angular amount that the worm wheel <NUM> rotates. For example, rotation of the worm wheel <NUM> by fifteen degrees clockwise may cause a corresponding fifteen degree rotation of the link <NUM>, etc..

In some embodiments, rotation of the link <NUM> may cause the proximal segment <NUM> to rotate. For example, the link <NUM> may be attached with the proximal segment <NUM>, such that rotation of the link <NUM> in a first or second rotational direction may cause a corresponding rotation of the proximal segment <NUM> in the first or second rotational direction, respectively.

In some embodiments, rotation of the worm wheel <NUM> may not cause the link <NUM> or proximal segment <NUM> to rotate. For example, the link <NUM> may be rotatably connected to the worm wheel. The middle and distal segments <NUM>, <NUM> may thus rotate while the proximal segment <NUM> does not rotate or rotates less as compared to a full rotation, as further described with respect to <FIG>. In some embodiments, actuation of the digit segments may be provided by the actuation tendon <NUM> attached to the worm wheel <NUM> and to the various segments <NUM>, <NUM>, <NUM>, such that rotation of the worm wheel <NUM> will cause the tendon to pull in (shorten) to cause rotation of the segments <NUM>, <NUM>, <NUM>. The return tendon <NUM> may rotate the digit <NUM> in the opposite direction, as described herein, and the worm wheel <NUM> may rotate in the opposite direction to allow the actuation tendon to pay out (lengthen).

The digit <NUM> may include the actuation tendon <NUM>. The tendon <NUM> extends from a proximal end <NUM> attached to the worm wheel <NUM> to a distal end <NUM> attached to an attachment <NUM> of the middle segment <NUM>. The tendon <NUM> extends distally from the worm wheel <NUM> and around an idler <NUM>, such as a pulley, which may or may not rotate, and that is connected to the proximal segment <NUM>. As the worm wheel <NUM> rotates clockwise as oriented from <FIG> (also shown in <FIG>), the proximal end <NUM> of the tendon <NUM> wraps around the worm wheel <NUM>. The tendon <NUM> effectively shortens in length and thus pulls on the attachment <NUM> and applies a force on the idler <NUM>, causing the middle and proximal segments, to which the attachment <NUM> and idler <NUM> are respectively attached, to rotate in the clockwise direction as oriented.

The digit <NUM> may include the return tendon <NUM>. The return tendon <NUM> extends from a proximal end <NUM> attached to the plunger <NUM>. The plunger <NUM> is biased in the proximal direction by a compression spring <NUM> inside the housing <NUM>. The tendon <NUM> extends from the housing <NUM> in a distal direction around an idler <NUM>, such as a pulley, which may or may not rotate, to a distal end <NUM> of the tendon <NUM> attached to an attachment <NUM> of the proximal segment <NUM>. As the proximal segment <NUM> rotates clockwise as oriented, due to the actuation tendon <NUM> as described, the attachment <NUM> pulls on the return tendon <NUM> causing the plunger <NUM> to move distally and compress or further compress the spring <NUM>. The spring <NUM> compresses further as the digit <NUM> rotates further clockwise. The spring <NUM> thus applies a biasing force in the proximal direction to the plunger <NUM>, biasing the tendon <NUM> in the proximal direction, and applying an opening or counterclockwise force to the proximal segment <NUM> via the attachment <NUM>. In some embodiments, the spring <NUM> may be a constant force spring to apply a constant return force to the segment <NUM> in various rotational positions.

As the worm wheel <NUM> is rotated counterclockwise as oriented to effectively lengthen or pay out the actuation tendon <NUM>, the biasing force on the return tendon <NUM> causes the proximal segment <NUM> to rotate open, or in the counterclockwise direction as oriented. Further, the spring-loaded expandable link <NUM>, as described herein, then pulls proximally on the middle segment <NUM> at the connection <NUM> to rotate the middle segment <NUM> counterclockwise about the joint <NUM>. The ear <NUM> may then rotate counterclockwise about the joint <NUM> to rotate the connection <NUM> of the distal link <NUM> counterclockwise about the joint <NUM> to rotate the distal segment <NUM> counterclockwise as well.

The tendons <NUM>, <NUM> are just one example of how to effect articulation of the segments <NUM>, <NUM>, <NUM> in the prosthetic digit <NUM> having the expandable link <NUM>. Some embodiments of the digit <NUM> having the expandable link <NUM> may not include the actuation tendon <NUM> and/or the return tendon <NUM>. For example, features other than tendons may be used, such as other links, connections, joints, segments, etc. Therefore, the embodiments shown and described herein for articulation of the segments <NUM>, <NUM>, <NUM> are merely example embodiments of how the prosthetic digit <NUM> with the expandable link <NUM> may be implemented.

As the link <NUM> rotates, the rotatable connection <NUM> of the link <NUM> with the middle segment <NUM> translates or sweeps a rotational path. The middle segment <NUM> is translationally constrained with the distal end <NUM> of the link <NUM> at the connection <NUM>. The middle segment <NUM> thus rotates relative to the link <NUM> about the connection <NUM> as the middle segment <NUM> is rotating to open or close the digit <NUM>. The middle segment <NUM> also rotates relative to the proximal segment <NUM> about the joint <NUM> (see <FIG>).

As the middle segment <NUM> rotates, the connection <NUM> at the proximal end <NUM> of the distal link <NUM> moves along the slot <NUM>. The connection <NUM> may include a pin sliding along the slot <NUM>. This allows the ear <NUM> to rotate relative to the distal link <NUM>. The distal link <NUM> thus rotates relative to the middle segment <NUM>. As the distal link <NUM> rotates, the distal segment <NUM> also rotates due to the connection <NUM> between the distal link <NUM> and the distal segment <NUM>. The distal segment <NUM> rotates relative to the middle segment <NUM> about the joint <NUM>.

As shown in <FIG>, the mount <NUM> or a portion thereof may extend along an Axis <NUM>. The proximal segment <NUM> may extend along an Axis <NUM>. The Axes <NUM>,<NUM> may form an angle A between them. The angle A may be the angular configuration of the proximal segment <NUM> relative to the mount <NUM>. The angle A may range from zero degrees (e.g., in <FIG>) to ninety degrees or more (e.g., in <FIG>). In some embodiments, the angle A may be negative fifteen, negative ten, negative five, zero, five, ten, fifteen, twenty, twenty-five, thirty, thirty-five, forty, forty-five, fifty, fifty-five, sixty, sixty-five, seventy, seventy-five, eighty, eighty-five, ninety, ninety-five, one hundred, one hundred five, one hundred ten, or one hundred fifteen degrees, or other lesser, greater or in between angular amounts. The various values for the angle A may apply to any of the articulated configurations of the prosthetic digit <NUM> shown in any of <FIG> and other configurations.

The angle A may change as the digit <NUM> rotates, for example as the middle and distal segments <NUM>, <NUM> rotate. As shown, the angle A may increase from the relatively open configuration of <FIG> to the relatively closed configuration of <FIG>, and vice versa. The angle A may be dependent on the amount of rotation of the middle and distal segments <NUM>, <NUM>, or vice versa. In some embodiments, the angle A may not change as the digit <NUM> rotates, for example as the middle and distal segments <NUM>, <NUM> rotate. For example, the angle A may not change from the relatively open configuration of <FIG> to the relatively closed configuration of <FIG>, and vice versa. In some embodiments, the angle A may change by a small amount from the relatively open configuration of <FIG> to the relatively closed configuration of <FIG>, and vice versa, for example by five degrees or less, ten degrees or less, fifteen degrees or less, or twenty degrees or less. The angle A therefore may not be dependent on the amount of rotation of the middle and distal segments <NUM>, <NUM>, or vice versa, as further described herein, for example with respect to <FIG>.

The digit <NUM> may rotate as described to have the closed configuration shown in <FIG>. The Axis <NUM> along which the proximal segment <NUM> extends may be at about ninety degrees to the Axis <NUM>. The middle segment <NUM> may be rotated to about parallel with the Axis <NUM>. In some embodiments, the middle segment <NUM> may not be parallel with the Axis <NUM> in the closed configuration. As also shown, the distal segment <NUM> is rotated clockwise to be adjacent to the proximal segment <NUM>. The segments <NUM>, <NUM>, <NUM> may thus rotate to provide a small closed grip with the digit <NUM>.

<FIG> are sequential views of the prosthetic digit <NUM> performing a rotation with added degrees of freedom. The digit <NUM> is shown in various rotated configurations where the middle and distal segments <NUM>, <NUM> rotate independently of rotation of the proximal segment <NUM> due to interaction of the links <NUM>, <NUM>. The digit <NUM> may rotate similarly as described with respect to <FIG>, except as otherwise described.

In some embodiments, the digit <NUM> may rotate to grab or cover an object having an irregular outer surface or contour. The rotational path of the digit <NUM> shown in <FIG> may not adequately cover or grasp the object due to the irregular outer surface. Thus the proximal and/or middle segments <NUM>, <NUM> may be prevented from rotating clockwise beyond an angular amount. In such case, the middle and/or distal segments <NUM>, <NUM> may continue to rotate to provide the desired functionality. <FIG> shown an example embodiment of rotation of the digit <NUM> where the proximal segment <NUM> does not rotate or does not completely rotate clockwise, while the middle and distal segments <NUM>, <NUM> rotate clockwise.

As the digit <NUM> rotates from <FIG>, the proximal segment <NUM> may be prevented from rotation. This may be due to a force exerted on the proximal segment <NUM> by an outside object that counteracts the closing direction, such as contact with a part of the object the digit <NUM> is grasping. The middle and distal segments <NUM>, <NUM> may continue to rotate due to the link <NUM> expanding. The link <NUM> as shown may elongate as the digit <NUM> rotates. The housing <NUM> may extend distally away from or proximally toward the fixed portion <NUM> as the digit <NUM> is rotated clockwise or counterclockwise, respectively. As shown in <FIG>, the angle A between the Axes <NUM> and <NUM> may therefore not change, or may change by a small amount, as described herein, for example with respect to <FIG>.

The link <NUM> may have a first axial length in <FIG> for instance where the digit <NUM> is straightened out, a second axial length in <FIG> where the digit <NUM> has partially rotated, a third axial length in <FIG> where the digit <NUM> is rotated farther but not completely, and a fourth axial length in <FIG> where the digit <NUM> is fully rotated. The first length may be shorter than each of the second, third and fourth lengths. The second length may be shorter than each of the third and fourth lengths. The third length may be shorter than the fourth length.

The middle and distal segments <NUM>, <NUM> rotate as described with respect to <FIG>. The expanding and retracting link <NUM> allows the middle and distal segments <NUM>, <NUM> to rotate without rotation or full rotation of the proximal segment <NUM>. In some embodiments, the link <NUM> may not rotate. In some embodiments, the link <NUM> may partially rotate. In some embodiments, a tendon may be used to cause rotation of the middle and distal segments <NUM>, <NUM> when the proximal segment <NUM> does not rotate or does not fully rotate. A tendon may be attached to the worm wheel <NUM> to cause rotation, as described with respect to <FIG>.

<FIG> are various views of another embodiment of a prosthetic digit <NUM>. The digit <NUM> may be used with the system <NUM> or hand <NUM>. The digit <NUM> includes a mount <NUM>, a proximal segment <NUM>, a middle segment <NUM>, and a distal segment <NUM>. The mount <NUM> and segments <NUM>, <NUM>, <NUM> may have the same or similar features and/or functions as respectively the mounts <NUM>, <NUM> and segments <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and thus may articulate, for example rotate, relative to each other, etc..

The digit <NUM> includes mechanically-connected rigid links, including a proximal link <NUM> and a distal link <NUM>. The links <NUM>, <NUM> may have the same or similar features and/or functions as the links <NUM>, <NUM>. For example, the mount <NUM> may be rotatably attached to the proximal end of the proximal link <NUM> about a connection <NUM>. The proximal link <NUM> is rotatably attached to the middle segment <NUM> of the digit <NUM> about a pivot <NUM>. The proximal link <NUM> may include a dogleg, where the proximal end of the proximal link <NUM> extends along a first axis and the distal end of the proximal link extends along a second axis that is at an angle relative to the first axis. The pivot <NUM> may be located at or near the vertex of the dogleg of the proximal link <NUM>. The distal end of the proximal link <NUM> is rotatably attached to the proximal end of the distal link <NUM> about a connection <NUM>. The distal end of the distal link <NUM> is rotatably attached to the distal segment <NUM> of the digit <NUM> about a pivot <NUM>.

The digit <NUM> includes an actuator <NUM>, which may have the same or similar features and/or functions as the actuators <NUM>, <NUM>, except as otherwise described. For example, the actuator <NUM> may include a motor <NUM> supplied with power from a battery, which may be in the hand or other location. The motor <NUM> may have an output shaft that extends, for example distally, therefrom, and that mechanically communicates with an off-axis shaft <NUM>.

The actuator <NUM> includes a worm wheel <NUM> and a worm gear <NUM>, which may have the same or similar features and/or functions as respectively the worm wheel and worm gear <NUM>, <NUM>, except as otherwise described. For example, the worm gear <NUM> having external threads <NUM> thereon may be in mechanical communication with the shaft <NUM> via the threads <NUM>. Actuation of the motor <NUM> causes motion to be transmitted via a pinion gear <NUM> (see <FIG>) to the shaft <NUM> to rotate the worm gear <NUM>. The worm wheel <NUM> may have external teeth <NUM> thereon. In some embodiments, only a portion of the outer circumference of the worm wheel <NUM> includes external teeth <NUM> (e.g., the portion of the outer circumference of the worm wheel <NUM> positioned adjacent to the worm gear <NUM>). The remainder of the outer circumference of the worm wheel <NUM> may be smooth or otherwise not have teeth. This configuration can advantageously allow for a compact worm wheel <NUM> and worm gear <NUM> system. The threads <NUM> (see <FIG>) of the worm gear <NUM> contact the teeth <NUM> of the worm wheel <NUM> to cause rotational motion of the worm wheel <NUM>. The worm wheel <NUM> may be rotated a first rotational direction to cause a first rotation of the digit <NUM> in a first direction (e.g. to close the digit <NUM>). The worm wheel <NUM> may be rotated in a second rotational direction that is opposite the first rotational direction to allow for a second rotation of the digit <NUM> in a second direction that is opposite the first direction (e.g. to open the digit).

<FIG> are various views of the actuator <NUM> of the digit <NUM>. <FIG> is a partial exploded view of the actuator <NUM>, and <FIG> show the actuator <NUM> with various features removed or hidden for clarity. The actuator <NUM> of the digit <NUM> may comprise a central axle <NUM> having a drive key <NUM> configured to engage a portion of the proximal segment <NUM> of the digit <NUM>. For example, in some embodiments, the drive key <NUM> is positioned on an outer surface of the central axle <NUM> and has an extended length and width protruding outwardly from the outer surface of the central axle <NUM>. An inner surface <NUM> of the proximal segment <NUM> of the digit <NUM> may comprise a mating feature <NUM>, such as a recess, opening, and/or groove, with a shape that corresponds with the shape of the drive key <NUM> of the central axle <NUM>. The mating feature <NUM> of the proximal segment <NUM> may receive the drive key <NUM> of the central axle <NUM> therein to transmit a rotational force from the central axle <NUM> to the proximal segment <NUM>. In some embodiments, the ratio of the rotational angle of the drive key <NUM> to the rotational angle of the proximal segment <NUM> is <NUM>:<NUM>.

In some embodiments, the central axle <NUM> includes a first drive key <NUM> protruding outwardly in a first direction from a first outer surface of the central axle <NUM> and a second drive key <NUM> protruding outwardly from a second outer surface of the central axle <NUM> in a second direction that is opposite the first direction. The proximal segment <NUM> may include a first inner surface <NUM> with a first mating feature <NUM> for receiving the first drive key <NUM> and a second inner surface <NUM> with a second mating feature <NUM> for receiving the second drive key <NUM>.

In some embodiments, the central axle <NUM> may include one or more drive tabs <NUM>. The drive tabs <NUM> may each have an extended, arcuate length and width protruding axially from an inner surface of the central axle <NUM>. In some embodiments, the central axle <NUM> includes a first drive tab <NUM> and a second drive tab <NUM> positioned radially opposite the first drive tab <NUM>.

In some embodiments, the worm wheel <NUM> may include one or more corresponding drive tabs <NUM>. For example, the worm wheel <NUM> may include a first drive tab <NUM> and a second drive tab <NUM> positioned radially opposite the first drive tab <NUM>. The drive tabs <NUM> of the worm wheel <NUM> may extend radially inward from an inner surface of the worm wheel <NUM> toward a central axis of the worm wheel <NUM>. The drive tabs <NUM> of the worm wheel <NUM> may be positioned between the first and second drive tabs <NUM> of the central axle <NUM>. In some embodiments, one or more of the drive tabs <NUM> of the central axle <NUM> engages one or more of the drive tabs <NUM> of the worm wheel <NUM> (e.g., contacts, abuts, connects to, etc.) to transmit a rotational force of the worm wheel <NUM> to the central axle <NUM>.

The drive mechanism of the digit <NUM> may include a spring <NUM> (e.g., a torsion spring). The spring <NUM> may be coupled to (e.g., circumferentially surround) an axially extending member <NUM> that extends axially along the central axis of the worm wheel <NUM> and/or central axle <NUM>. The spring <NUM> may be configured to rotationally bias the worm wheel <NUM> in an angular direction to maintain the relative positions of the central axle <NUM> and the worm wheel <NUM>. For example, the spring <NUM> may include a flange <NUM> that extends further radially outward than the rest of the spring <NUM>. The flange <NUM> may engage one of the drive tabs <NUM> of the worm wheel <NUM>. For example, in some embodiments, the worm wheel <NUM> and the central axle <NUM> are positioned such that one of the drive tabs <NUM> of the central axle <NUM> abuts a first surface of one of the drive tabs <NUM> of the worm wheel <NUM> and the flange <NUM> abuts a second surface of the drive tab <NUM> opposite the first surface of the drive tab <NUM>. This configuration enables the rotational force of the worm wheel <NUM> to be transmitted to the central axle <NUM> while maintaining the relative positions of the worm wheel <NUM> and the central axle <NUM>. This configuration also allows the digit <NUM> to be closed independent of the drive mechanism of the digit <NUM>, as further described below.

In some embodiments, the digit <NUM> may be opened and/or closed with or without utilizing the actuator <NUM>. For example, the digit <NUM> can have a worm wheel driven movement mode (e.g., driven by the actuator <NUM>) and a manual movement mode (e.g., driven by an external force). When the digit <NUM> is in an open position, application of an external force on the digit <NUM> in a closing direction may cause the digit <NUM> to fold to a closed position. In some embodiments, in the manual movement mode, unlike in the worm wheel driven movement mode, the actuator <NUM> does not drive the worm wheel <NUM>. For example, in the manual movement mode, the actuator <NUM> and the worm wheel <NUM> remain stationary. In the manual movement mode, the central axle <NUM> rotates in response to the application of an external force to the digit <NUM> while the worm wheel <NUM> remains stationary because the spring flange <NUM> allows for rotational movement when its spring biasing force is overcome. The rotation of the central axle <NUM> may cause the segments <NUM>, <NUM>, <NUM> of the digit <NUM> to rotate to a closed position. In the manual movement mode, the projections <NUM> of the worm wheel <NUM> may limit the range of rotation of one or more of the drive tabs <NUM> of the central axle <NUM> and therefore the range of rotation of the central axle <NUM>. The spring <NUM> may rotate and store energy due to the manual movement of the digit <NUM> to the closed position due to the application of an external force to the digit <NUM>. In some embodiments, when the external force is removed from the digit <NUM>, the spring <NUM> may use the stored potential energy to rotate and cause the digit <NUM> to return to the open position.

The manual movement mode of the digit <NUM> can advantageously serve as a mechanical protection system when external forces act on the digit <NUM>, such as when a user falls on the digit <NUM> or applies pressure to the digit <NUM> to get up from a chair, etc. The manual closure of the digit <NUM> may allow the external load to be supported by components of the digit <NUM> other than the drive mechanism (e.g., gearbox). This can prevent damage that may otherwise have been caused to the drive mechanism of the digit <NUM>.

<FIG> illustrates the positions of encoders <NUM>, <NUM> within the digit <NUM>. In some embodiments, the digit <NUM> includes a plurality of encoders <NUM>, <NUM> mounted to the gearbox. For example, in some embodiments, the digit <NUM> includes a first type of encoder for the worm wheel driven movement mode and a second type of encoder for the manual movement mode. As shown, the digit <NUM> may include a potentiometer strip encoder <NUM> and a magnetometer encoder <NUM>. The potentiometer strip encoder <NUM> may be coupled to the worm wheel <NUM>. The magnetometer encoder <NUM> may be positioned between the potentiometer strip encoder <NUM> and the pinion gear <NUM>. The potentiometer strip encoder <NUM> may measure the position of the digit <NUM> by measuring the absolute position of the motor drive. The magnetometer encoder <NUM> may be an absolute magnetic hall effect encoder. The magnetometer encoder <NUM> may measure the position of the digit <NUM> by measuring the degree of rotation of a diametrically magnetized axial magnet disposed within the axially extending member <NUM> at the center of the central axle <NUM>.

<FIG> is a cross-sectional view of a portion of the digit <NUM> illustrating waterproof seals <NUM> within the digit <NUM>. In some embodiments, the digit <NUM> may be waterproof (e.g., rated IP68). The digit <NUM> may include seals <NUM>, such as O-ring seals, lip seals, and/or other dynamic seals, to seal the components within the central axle <NUM> from water ingress. For example, the seals <NUM> may be positioned in gaps between the central axle <NUM> and the mount <NUM>.

Various modifications to the implementations described in this disclosure can be readily apparent to those skilled in the art, and the generic principles defined herein can be applied to other implementations without departing from the spirit or scope of this disclosure. Thus, the disclosure is not intended to be limited to the implementations shown herein, but is to be accorded the widest scope consistent with the claims, the principles and the novel features disclosed herein. The word "example" is used exclusively herein to mean "serving as an example, instance, or illustration. " Any implementation described herein as "example" is not necessarily to be construed as preferred or advantageous over other implementations.

Certain features that are described in this specification in the context of separate implementations also can be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation also can be implemented in multiple implementations separately or in any suitable sub-combination. Moreover, although features can be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination can be directed to a sub-combination or variation of a sub-combination.

Additionally, other implementations are within the scope of the following claims.

Claim 1:
A prosthetic digit (<NUM>) comprising:
a mount (<NUM>) configured to attach to a hand (<NUM>);
a proximal segment (<NUM>), a middle segment (<NUM>), and a distal segment (<NUM>), wherein the proximal segment is rotatably attached to the mount at a first pivot (<NUM>), and the middle segment is rotatably attached to the proximal and distal segments;
an actuator (<NUM>) coupled with the mount and the proximal segment, the actuator including a housing (<NUM>), the housing defining a cavity (<NUM>); and
a leadscrew (<NUM>), the leadscrew having external threads (<NUM>) in mechanical communication with internal threads of the housing;
wherein rotation of the leadscrew causes axial translation of the housing along an axis defined by the cavity, and wherein the axial translation of the housing causes the proximal segment to rotate about the first pivot, wherein rotation of the proximal segment about the first pivot causes the middle and distal segments to rotate.