Patent Description:
Prosthetic hands having a plurality of movable digits are well known and one such device is described in <CIT> to the same inventor as the present invention. Such devices generally comprise one or more digits which are each engineered so as to replicate, as far as possible, the natural movement of a real digit. For example, a prosthetic finger will be provided with three portions each linked to the other by means of an articulated joint and being shaped and sized such as to replicate as near as possible a natural finger. A prosthetic thumb may be provided with just two portions which are linked to each other by a similar articulated joint and similarly shaped and sized to replicate, as near as possible, a natural finger. Each of the prosthetic fingers and / or the prosthetic thumb is joined to the main body of the prosthetic hand by means of a further linkage so as to allow the respective finger or thumb to pivot relative to the main body of the prosthetic hand. <CIT> also discloses a prosthetic finger comprising an actuator which allows flexion of the digit. To date the joints have tended to be hinged arrangements which provide sufficient movement to allow the hand to perform all the essential functions but prevent the prosthetic hand from functioning in the manner of a natural hand and prevents the prosthetic hand replicating the more natural and less restricted movement of a natural hand. In addition, the actuators for such hands tend to be employed for each portion of each digit and, hence, the actuation system can be more bulky and heavy than might be desired. This problem would be compounded if further actuators were to be provided in order facilitate any additional movement.

It is an object of the present invention to provide a prosthetic hand having one or more digits in which one or more of the one or more digits is able to move in a controlled manner by rotation or lateral movement in addition to the already established single plane motion of existing prosthetics. It is a further object of the present invention to provide an actuator for such prosthetic digits which is able to provide a driving motion in more than one plane and/or about one or more axis.

Accordingly, the present invention provides a prosthetic device comprising an anchor portion that may comprise a bearing part and a housing part. A base portion may have a proximal side and a distal side connected to said anchor portion through a bearing part. An elongate digit having a proximal end and a distal end and extends along or substantially along a longitudinal axis X. A first portion of a pivot connection may be mounted on the base portion. A second portion of a pivot connection may be mounted on the proximal end of the digit and may be connected to the first portion of the pivot connection. An actuator to cause pivotal movement of said digit around said pivot connection. Said base portion may include a second longitudinal axis X2 extending between said proximal side and said distal side and a bearing between the base portion and said anchor portion. Said base portion may be mounted to said anchor portion via said bearing and may be be rotatable about said second longitudinal axis X2.

In an alternative embodiment, the prosthetic device may including a rotation actuator for causing rotational movement of the digit within said bearing about said second longitudinal axis X2.

In a further alternative embodiment, said rotational actuator of the prosthetic device may comprise a motor mounted within the digit. The prosthetic device may further include a torque tube connected at a first end to the rotational actuator and at a second end to the anchor.

In a further alternative embodiment of the prosthetic device said digit may comprise a thumb.

In a further alternative embodiment, the prosthetic device may have a palm portion and wherein said anchor portion may be mounted on said palm portion.

In a further alternative embodiment, the prosthetic device may include a plurality of prosthetic digits, such as, for example as described herein.

In a further alternative embodiment, the prosthetic device may include a controller for controlling the operation of one or more of said digits.

In a further alternative embodiment the prosthetic device may comprise a prosthetic thumb and a plurality of prosthetic fingers. Said controller may operate to cause rotation of the prosthetic thumb in combination with pivotal movement of said thumb as said thumb moves towards said prosthetic fingers.

In a further alternative embodiment of the prosthetic device said bearing may comprise a hollow bearing having an internal aperture for receiving power or actuation connections.

According to a second aspect of the present invention there is also provided a prosthetic device comprising an anchor portion; a base portion having a proximal side and a distal side and being connected to said anchor portion. An elongate digit may have a proximal end and a distal end extending along a longitudinal axis X. A first portion of a pivot connection may be mounted on the base portion. A second portion of a pivot connection may be mounted on the proximal end of the digit and may be connected to the first portion of the pivot connection. A linear actuator within the elongate digit may have a first portion secured to the elongate digit for movement therewith and a second portion remote therefrom, axially movable relative thereto acting against the base portion, being operable with said pivot connection, thereby to cause pivotal movement of said digit around said pivot connection upon axial movement of said second portion of said linear actuator.

In an alternative embodiment of the prosthetic device said second portion of said linear actuator may include one or more transfer pivot pins extending outward therefrom. Said base portion may include one or more apertures for receiving said one or more transfer pivot pins. Wherein said apertures may be radially displaced relative to the pivot connection such as to allow for pivotal movement of said digit about said pivot connection upon axial translation of said second portion of the linear actuator.

In an alternative embodiment of the prosthetic device said first side and second side of said digit may be contained between said first and second sides of said base portion. Wherein each of said first and second sides may include a slot or means defining a slot, each of said slots extending along said longitudinal axis X of said digit and may receive respective second transfer pins therethrough. In a further alternative embodiment of the prosthetic device said base portion may include a second longitudinal axis X2 extending between said proximal side and said distal side and may further include a bearing between the base portion and said anchor portion. Said base portion may be mounted to said anchor portion via said bearing and may be rotatable about said second longitudinal axis X2.

In a further alternative embodiment, the prosthetic device may include a rotation actuator for causing rotational movement of the digit within said bearing about said second longitudinal axis X2.

In an alternative embodiment of the prosthetic device said rotational actuator includes a torque tube connected at a first end to the rotational actuator and at a second end to the anchor at point.

In an alternative embodiment of the prosthetic device the torque tube may extend through said bearing.

In an alternative embodiment of the prosthetic device said digit may comprise a thumb.

In an alternative embodiment the prosthetic device may have a palm portion, wherein said anchor portion may be mounted on said palm portion.

In an alternative embodiment of the prosthetic device may include a plurality of prosthetic digits.

In an alternative embodiment the prosthetic device may include a controller for controlling the operation of one or more of said digits.

In an alternative embodiment the prosthetic device may include a first load sensor for sensing external resistance to pivotal movement of said one or more digits.

In an alternative embodiment the prosthetic device may include a second load sensor for sensing external resistance to rotational movement of said one or more digits.

In a further alternative embodiment, the prosthetic device may comprise a prosthetic thumb and a plurality of prosthetic fingers. Said controller may operate to cause rotation of the prosthetic thumb in combination with pivotal movement of said thumb as said thumb moves towards said prosthetic fingers.

The above-mentioned arrangements allow the digit to be mounted onto an anchor portion which can then be mounted on, for example, a palm portion and a plurality of such digits and base portions may be mounted onto a common anchor portion such as, for example, a palm portion of a prosthetic hand. The arrangement also allows for the positioning of the actuation motor within the digit itself which allows for the creation of a slimmer and more aesthetically pleasing finished product that more easily replicates the natural shape and dimensions of a human hand. In particular, the arrangement lends itself to use in the production of smaller hands such as may be required for children or adults with naturally smaller hands. The base portion also allows for a further degree of freedom of movement described later herein.

In the following, various embodiments will be described, the scope of the invention is however solely defined by the scope of the appended claims.

The present invention will now be more particularly described with reference to the accompanying drawings, in which:.

Referring now to the drawings in general but with particular reference to <FIG>, a prosthetic device <NUM> may include one or more thumbs and/or fingers referred to herein generally as digits <NUM>, each of which is mounted on a base portion <NUM> which, in turn, is mounted onto an anchor <NUM>. The anchor <NUM> may comprise the main body or palm of a prosthetic hand or may comprise a sleeve or cover to be placed over a portion of the user's natural hand if portions thereof are present. Such may be the case where the patient has lost one or more digits but not an entire hand. The one or more digits <NUM> are each provided with an actuation mechanism or motor <NUM>, <NUM> for creating one or other or both of pivotal and / or rotational movement of the digit in question <NUM>. These mechanisms <NUM>, <NUM> may be provided as separate units, as shown herein, or may be combined as one unit if so desired and each are described in more detail later herein. The digits <NUM> are each provided with a proximal end 14a closest to the anchor <NUM> and a distal end 14b remote therefrom. The proximal end 14a is pivotally connected to the base portion <NUM> by means of a pivot shown generally at <NUM> and also described in more detail alter herein. One or more of the one or more digits may have a base portion <NUM> which is connected to the anchor <NUM> by means of a rotational mount in the form of, for example, a bearing shown generally at <NUM> which facilitates the base portion <NUM> and the digit <NUM> rotating about a second axis X2. Again, this feature is described in more detail later herein. It will be appreciated that the arrangement of mounting the digit <NUM> to a base portion <NUM> which is, in turn, connected to an anchor <NUM> which forms part of the main body of a prosthetic hand may be used with or without the further feature of the base portion (and hence the digit) being rotatable about the second longitudinal axis X2. It will also be appreciated that the rotational aspect of the present invention may be incorporated into prosthetic digits without the specific actuator arrangement as shown in this particular document but that a significant advantage may be gained by incorporating the two in one product.

Referring now more particularly to <FIG> which is an exploded view of the digit <NUM> of <FIG>, it will be seen that the digit has a longitudinal axis X and is mounted at a proximal end 14a to the base <NUM> by means of a pivot <NUM> operational around a third axis Y which is generally perpendicular to axis X and which may comprise a first portion 16a forming, for example, an aperture on the base <NUM> and a second portion 16b on the proximal end 14a of the digit <NUM> itself. in the particular arrangement of the drawings, said base portion <NUM> includes first and second sides 12a, 12b projecting therefrom in a common direction D and being spaced apart from each other by an amount S and wherein each side 12a, 12b includes a first portion of the pivot connection 16a and wherein said digit <NUM> includes a first side 14d and a second side 14e and wherein said first side 14d includes a first portion 16b1 of the pivot connection 16b and said second side 14b of the digit <NUM> includes a second portion 16b2 of the pivot connection 16b and wherein each of said second portions 16b1, 16b2 of the pivot connection 16b extend into respective first portions 16a of the pivot connection <NUM> when assembled. The digit <NUM> further includes a linear actuator <NUM> contained therein and having a first portion 40a secured to the elongate digit <NUM> for movement therewith and a second portion 40b remote therefrom and axially movable relative thereto, as shown by arrow A in <FIG>.

The second portion 40b of said linear actuator <NUM> may include one or more transfer pivot pins 40d, 40e extending outward therefrom whilst said base portion <NUM> may include one or more apertures 32a, 32b for receiving said one or more transfer pivot pins 40d, 40e. The apertures 32a, 32b are radially displaced by an amount R relative to the pivot connection <NUM> such as to allow for pivotal movement of said digit <NUM> about said pivot connection <NUM> upon axial translation of said second portion 40b of the linear actuator <NUM>. In essence, the second end or portion of the actuator 40b, pushes against apertures 32a, 32b and as the other end of the linear actuator <NUM> is connected to the digit <NUM> this will cause the digit <NUM> to pivot about the pivot connection <NUM> and axis X. this movement will cause the digit <NUM> to replicate the opening and closing of the digit and control of the linear actuator may be initiated in accordance with a desired control sequence or instruction as and when desired from a controller shown schematically at <NUM>.

As can be seen more clearly in some of the later drawings, the proximal end 14a of the digit(s) <NUM> are located such that the first side and second sides 14d, 14e of said digit are contained between said first and second sides 12a, 12b of said base portion <NUM>.

As mentioned above, each of said first and second sides 12a, 12b include respective apertures 32a, 32b for receiving respective second portions 40d, 40e of the pivot <NUM>. The first and second portions 14d, 14e of the digit <NUM> are each provided with a respective slot 20a, 20b at their respective proximal ends 14a extending along said longitudinal axis X of said digit <NUM> and these slots 20a, 20b receive respective transfer pivot pins 40d, 40e of actuator <NUM> therethrough such as to allow the linear actuator <NUM> to be connected to the anchor <NUM>. The slots 20a, 20b extend for a sufficient length as to allow for the full and free movement of the linear actuator as and when desired. Movement of transfer pivot pins 40d, 40e will cause the digit <NUM> to pivot about pivot connection <NUM> as will be described in more detail later herein.

The base portion <NUM> may, in one embodiment of the invention, also include a second longitudinal axis X2 extending between said proximal side 12a and said distal side 12b and a bearing <NUM> may be provided between the base portion <NUM> and said anchor portion <NUM> such that said base portion <NUM> is mounted to said anchor portion <NUM> via said bearing <NUM> and rotatable about said second longitudinal axis X2 as and when required. The bearing <NUM> may comprise a hollow bearing include an internal aperture <NUM> for allowing the passage of portions of a rotational actuator or electrical or operational supply cabling to be provided therethrough.

This capability is new to prosthetic digits and may be used to provide the user with a higher degree of motion and possibly a greater degree of feedback than has been previously known in the field of prosthetic digits. The device <NUM> may also include a rotation actuator <NUM> for causing rotational movement of the digit <NUM> within said bearing <NUM> about said second longitudinal axis X2. Such a rotational actuator <NUM> may be housed within the digit itself <NUM> or may be mounted remotely therefrom, although advantages of compactness and controllability will be present if the rotational actuator is mounted within the digit itself <NUM>. Whilst there are a number of rotational actuator arrangements that could be used, it has been found that an arrangement in which the rotational actuator <NUM> is housed within the digit and anchored relative thereto will allow for the use of a torque tube <NUM> extending therefrom which can be connected at a first end 82a to the rotational actuator <NUM> and at a second end to the anchor <NUM>. The anchor <NUM> is comprised of two parts, a rotation housing 30a wherein the base portion <NUM> pivots around axis X2, and a housing 30b wherein the torque tube proximal end 82b is connected. The torque tube <NUM> is connected at its first end 82a to the rotation actuator <NUM>, and at its second end 82b to the housing 30b at point 30c. Housing 30b and the rotation housing 30a are both connected to the palm of the hand <NUM>. The torque tube <NUM> may extend through bearing <NUM> or may pass around it if space permits. The torque tube may also be hollow and include a first opening 82a thereinto for receiving any electrical wiring or connections thereinto and a second opening 82b for allowing any such electrical wiring or connections to be routed out of the torque tube <NUM>. The first and second openings 82a, 82b may be on the first and second ends 82a. Preferably, the torque tube is sufficiently flexible so as to allow for the desired degree of movement of the digit <NUM> but is sufficiently resistant to rotation as to ensure the desired rotational movement is transmitted. Such an arrangement would allow for the transmission of rotational torque from the rotational actuator <NUM> through the torque tube <NUM> to the anchor <NUM> at which point it is reacted and this will cause the base portion <NUM> and digit <NUM> to rotate about axis X2. Again, the rotational actuator <NUM> may be operably connected to a controller shown schematically at <NUM> and may be operated by said controller as and when desired.

The above design provides a prosthetic device <NUM> with one or more digits <NUM> which can, if desired, have compound movement in the sense that they can each move about two axes, one of which replicates the normal bending of a human digit and one of which replicates the rotational movement which is normally associated with a thumb but which could be used on the fingers of a prosthetic device. It also provides a prosthetic device which is able to be relatively compact and may allow for the production of smaller prosthetic devices than has been known until now.

The above arrangement may be added to in a number of ways. For example, the digit <NUM> may be provided with a first load sensor <NUM> (which may be a microprocessor) for sensing external resistance to pivotal movement of said one or more digits <NUM>. Such a sensor may be used to provide feedback on the strength of grip being applied to an object. The arrangement may also include a second load sensor (<NUM>) for sensing external resistance to rotational movement of said one or more digits (<NUM>). Again, this may be used to provide feedback on the strength of any grip being asserted by the digit. Still further, the digit may be provided with an overload mechanism in the form of spring-loading of the mechanisms arranged such as to provide a degree of resilient resistance to motion which would accommodate any overload through resilient motion. In the example of the rotational arrangement using a torque tube <NUM>, the resilience to rotational motion could be incorporated by way of the torque tube itself being a spring or having resilient properties. In the example of the linear actuator <NUM>, the resilience may be built into the mechanism by which the movable second portion 40b is connected to the static first portion 40a which, again, may include resilient members or spring arrangements.

In a preferred embodiment the torque tube <NUM> allows the electrical cables from actuators <NUM> and <NUM> to pass through it, thus allowing a smooth and minimally moving path.

Thus far we have described a single digit arrangement <NUM> forming one or other of a thumb or finger of a prosthetic device. It will, however, be appreciated that a partial or compete prosthetic hand may be assembled from or including the above-described components. A partial hand may comprise one or more digits whilst an entire hand would comprise all the digits in the form of both fingers and thumbs. It will be appreciated that aspects of the present invention may be provided on the thumb and / or the fingers of a prosthetic device and that further actuation mechanisms may be provided in addition to those described herein.

Rotational movement of the digit <NUM> is shown in <FIG> whilst the opening and closing of a full prosthetic hand is shown in <FIG>. From these figures it will be appreciated that a full or partial prosthetic hand may be provided simply by attaching one or more of the above-mentioned digits <NUM> onto a socket portion or glove portion for fitting over the hand of a patient requiring less than a full prosthetic replacement of digits or a palm portion of a prosthetic device where a full set of digits is required. For convenience each of the glove portion and palm portion will be referred to hereafter as a palm portion and provided with a single reference number <NUM>. Those skilled in the art will, however, appreciate that the digit and the following may be applied to either the glove or full palm arrangement. In each of the arrangements of <FIG> the base portion <NUM> of each of the one or more digits <NUM> is connected to the anchor <NUM> as described above but now each anchor <NUM> is, itself, mounted onto the glove / palm <NUM> in a pattern designed to replicate a full hand or replace missing digits if a partial replacement is desired. Each digit is as described above but it will be appreciated that one may dispense with the rotational element of the digit <NUM> when the invention is applied to the fingers as fingers may not need to have rotational movement capability. The thumb may also be provided without rotational capability, but this is not a preferred arrangement of the present invention.

Claim 1:
A prosthetic device (<NUM>) comprising:
a) An anchor portion (<NUM>);
b) a base portion (<NUM>) having a proximal side (12a) and a distal side (12b) and being connected to said anchor portion (<NUM>);
c) an elongate digit (<NUM>) having a proximal end (14a) and a distal end (14b) and extending along a longitudinal axis (X);
d) a first portion of a pivot connection (16a) mounted on the base portion (<NUM>);
e) a second portion of a pivot connection (16b) mounted on the proximal end (14a) of the digit (<NUM>) and being connected to the first portion (16a) of the pivot connection (<NUM>);
f) a linear actuator (<NUM>) within the elongate digit (<NUM>),
characterised by said linear actuator having a first portion (40a) secured to the elongate digit (<NUM>) for movement therewith and a second portion (40b) remote therefrom, axially movable relative thereto and acting against the base portion (<NUM>), being operable with said pivot connection (<NUM>), thereby to cause pivotal movement of said digit (<NUM>) around said pivot connection (16a, 16b) upon axial movement of said second portion (40b) of said linear actuator (<NUM>).