GB2488365A - Artificial digit with squeezable sack operation - Google Patents

Abstract

A replacement digit is in communication with a fluid sack or bladder 3. The digit may include pistons 14 that are driven by fluid displaced from the sack when it is compressed, resulting in the digit being able to grip objects. The digit may include return springs to bring it back to a resting position. The digit may be a finger, thumb or toe. The digit and sack may be provided as part of a glove 2. The fluid sack may provide movement possibilities for more than one digit.

Description

Field of the Invention

The present invention relates to replacement digit; more particularly a prosthetic digit with self powered movements.

Backnrouncj Increased medical effectiveness means that frequently hands or feet can be saved from trauma. In many cases military personnel suffer explosive or incendiary trauma where once the chances were significantly lower.

However loss of fingers, thumbs or toes on their hands or feet is a concurrent feature and although fingers, thumbs or toes can be reattached in hospital conditions with some success given the right conditions, these conditions are not always available.

Prior Art

In order to address the problem of a loss of a finger, thumb or toe, the following solutions have been suggested: International patent application WO 2008 062 625 (OKUDA et al) discloses a multi-fingered robot hand which includes a plurality of finger mechanisms, comprising: a first palm portion provided with at least one finger mechanism connected by a first root joint; a second palm portion provided with at least one finger mechanism connected by a second root joint; and a connecting portion connecting the first palm portion and the second palm portion, wherein: the connecting portion has a rotation axis for varying a connection angle of the second palm portion to the first palm portion and permits a variation in the connection angle of the second palm portion to the first palm portion; the first root joint has a rotation axis for bending the corresponding finger mechanism to its palm side; the second root joint has a rotation axis for bending the corresponding finger mechanism to its palm side; and the rotation axes are all substantially parallel to each other.

Granted European patent EP 1 962 737 discloses a hand prosthesis comprising a chassis, to which a finger prosthesis is articulated, said finger prosthesis being movable relative to the chassis about at least one pivot axis by means of a drive, wherein a first drive is arranged in the chassis and is coupled by means of a force transmission device to the finger prosthesis, and allows pivoting about a first pivot axis, and in that a second drive is provided, which allows pivoting of at least one part of the finger prosthesis about a second pivot axis relative to the first pivot axis, characterised in that the second drive is arranged in the finger prosthesis and is coupled by means of a gear mechanism with non-intersecting axes to an output element, the output element being formed as a worm, which meshes with a gear wheel segment and forms a worm gear mechanism.

International patent application Wa 2007 076 763 (PUCHHAMMER) discloses a chassis to which at least one finger prosthesis is articulated. The finger prosthesis is movable about at least one swiveling axis by means of a drive which is connected to the finger prosthesis by means of a force transmission unit. The force transmission unit between the drive and the finger prosthesis is yielding under pressure or elastic under bending and rigid under tension.

United States patent application US 5 568 957 (HAUGS) discloses a fluid actuable gripping apparatus comprising: a) at least one gripping and holding finger; b) said at least one finger comprising at least two interconnected casings of non-elastic soft and flexible materials defining at least two chambers having at least one common wall, said finger being initially shaped into a predetermined gripping configuration, said finger being responsive to fluid inflation to enhance its resistance to deflection from said predetermined gripping configuration as a function of increasing fluid pressure within said casing; and c) a first regulating vane connection coupled to the interior of at least one of said casings and couplable to a source of pressurized fluid for facilitating controlled inflation and deflation of said finger.

None of the above provides a realistic, self-powered and therefore minimally intrusive digit that may be used to replace a lost finger, thumb or toe or combination of such successfully, convincingly and with the least discomfort or inconvenience, whilst providing the user with a good approximation of the lost finger, thumb or toe(s).

Summary of the Invention

According to the present invention there is provided at least one replacement digit in communication with at least one fluid sack.

In preferred embodiments the fluid sack is attached to or activated by an existing finger, thumb or toe. Further embodiments have sacks attached to other bodily parts.

Ideally the prosthetic finger, thumb or toe will include sprung and/or pneumatic pistons which compress in response to pressure on the fluid sack and consequent displacement of fluid into the piston or piston activator. In preferred embodiments therefore the movement of a remaining finger, thumb or toe acts to move the digit.

In some embodiments the fluid sack is used to operate a plurality of digits, with movement of remaining digits and/or hand/foot sufficient to cause a well positioned fluid sack to move all the digits. Partitioned, restricted or divided fluid sacks may be utilised such that movement of the hand/foot and/or remaining digits will cause a variety of combined or independent movements for replacement digit(s).

In yet further embodiments a plurality of fluid sacks is provided which may be interconnected but typically all have a displaceable segment which acts to move the digit or digits, either through displacement or generation.

Ideally therefore in such embodiments by making the movements associated with moving the missing digit, the user palm will compress the fluid sack and hence move the replacement digit. This is intended to replicate a user's natural inclination of movement, so as that the hand or foot is flexed the digit moves as the lost finger, toe or thumb would have been inclined to.

Such fluid sacks may be contained in a tight fitting glove or sock, such that maximum movement is transmitted from the hand or foot into the fluid and its displacement in order to transmit the movement. This glove or sock may be worn throughout daylight hours or simply in certain limited circumstances such as where an extra digit is useful, for example in lifting weights.

Lifting items in particular is liable to displace large amounts of fluid, with the item's weight acting to displace the fluid when the weight is held in the hand or palm.

Typically therefore strapping will be provided on the glove or sock. This strapping may be fastened, attached or tightened by buckles, hook and loop, press studs or other appropriate method in order to ensure that a tight fit is achieved. Accordingly varying embodiments may be provided in appropriate sizing for the users hand or foot.

The strapping may be preferably composed in part or whole of permeable and/or breathable material or mesh or perforated material, such that the hand or foot is capable of breathing and/or perspiring.

In further embodiments the fluid sack or sacks may be held within a webbing which holds the sack(s) in the correct locations for displacement of fluid under appropriate movement. Yet further embodiments may webbing or strapping materials or fabrics that include elastic elements, such as Lycra (Trade Mark).

The fluid that is contained within the fluid sack or sacks may include gas, gel or high or low viscosity liquids as found to be most appropriate. In any event it is preferable that the fluid is non-corrosive.

The material of the sack(s) is ideally thin in order to transmit the maximum displacement and/or movement but strong enough to resist tearing or punctures. In some embodiments the fluid sacks may be multitudinous in such a way as to ensure that small fluid sacks react to movement and transmit displacement in as targeted a way as possible. In such embodiments it is envisaged that gloves or socks will be custom made or tailored to a user's requirements.

Further embodiments may include battery power in order to augment or increase the power available for movement of the replacement digit. This may combine with the fluid sack(s) such as with the inclusion of a microturbine or other transducer by harvesting and storing energy produced by movement of the hand or foot that is not related to the replacement digit, i.e. general hand or foot movement.

Yet further embodiments include sensors on or in contract with the hand or foot which relate to or relay movement of specific areas of the hand or foot. These sensors then pass the movement through to the digit, said digit thereby being moved accordingly by use of electrical power provided by the battery. This may be in addition to the fluid sack(s) movement or transference, or said sensors may be connected to or situate in said sack(s).

Brief Description of Figures

Figures 1 shows a front view of a preferred embodiment of the digit and sack, connected to a glove; Figure 2 shows a reverse view of the embodiment; Figure 3 shows a cross section of a preferred embodiment of the digit; Figure 4 shows a side view of the embodiment; Figure 5 shows an isometric view of the embodiment; and Figures 6 show two views of an embodiment of the digit.

petailed Description of Preferred Embodiment of the Invention In Figures 1 and 2 the digit is pictured attached to a glove 2. This glove 2 is formed in a breathable and elastic material and as pictured ideally covers a minimum of the user's hand, allowing free movement of the user's thumb and remaining fingers.

Ideally the digit is capable of attachment or location on the remainder of a severed finger, thumb or toe, perhaps by means of a hollow core 11 and/or rubber or elastomer gromits or rings 12 (Figure 6). In this way the digit may be understood to be an appropriate part of a finger, thumb or toe.

The glove may be made of polyester with a cotton inner having an attachment or fastening strap which may be disposed with Velcro (Trade Mark), hook and loop or other fastening means such as poppers or push studs (20).

In use the digit is fitted to a pivoting hook (13) on the front face of the glove and secured to a screw pin (14) on the rear. A brace (15) disperses the transfer of force from any movement of the finger along the back of the users hand and around his or her wrist.

In the pictured embodiment there is provided a separate connected fluid pouch (3) which is attached to a finger typically by hook and loop and/or elasticated strapping 31, connected via a fluid valve (not pictured) to fluid displacement pistons by a microbore tube (30).

A prosthetic sleeve (not pictured) may be slid over the digit to cover the mechanics of the digit for aesthetic, safety or damage avoidance reasons. This combines with the use of blanking covers (10) of polymer in the pictured embodiment which form fingerpads.

The user can then perform basic operations such as lifting and moving objects. As the user picks up an item (not pictured), the item's weight displaces the fluid from the pouch (3) into the micro-pistons (14) thereby moving the blanking covers/ fingerpads by rotating the hinges 17. This results in an upwards force, aiding lifting.

Torsion springs are pictured (15) to return the digit to a largely erect, resting position.

Multiple pouches may be disposed on multiple fingers. When the user bends the remaining fingers in communication with fluid displacement and the pistons (14) therefore the fluid is displaced from the pouch(es) to the pistons, causing the digit to mimic the bending motion.

In further embodiments the digit can also be used to benefit toe amputees balance when walking or running as at least one fluid pouch may be located under the user's foot and displacement may occur as pressure is applied.

The invention has been described by way of examples only and it will be appreciated that variation may be made to the above-mentioned embodiments without departing from the scope of invention.

With respect to the above description then, it is to be realised that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention.

Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.

Claims (7)

1. Claims 1. At least one replacement digit in communication with at least one fluid sack.
2. 2. A digit according to claim 1 wherein the replacement digit includes pistons.
3. 3. A digit according to claims 1 or 2 wherein the pistons are driven by the fluid.
4. 4. A digit according to claims I or 2 wherein the pistons are driven by displacement of the fluid.
5. 5. A means of movement of replacement digits according to any preceding claim.
6. 6. A means according to claim 5 wherein the digits move in tandem.
7. 7. A means according to claim 5 wherein the digits move independently.Amendments to the claims have been filed as follows.Claim!1 A mechanism for enabling the user of prosthetic digits to move them in unison with his remaining digits or, as the case may be, the remaining part of his hand or foot, in which the prosthetic digits are moved as follows-- (a) the user applies muscle pressure to fluid sacks that are ergonomically fitted to his remaining digits or, as the case may be, the remaining part of his hand or foot and the sacks are so connected to pistons inside the prosthetic digits that the displaced fluid drives the pistons and they in turn move the prosthetic digits, and (b) as soon as the muscle pressure is relaxed, return springs secure that the prosthetic digits, pistons and fluid go back to their original positions; and section 6 of the Interpretation Act 1978 (gender and number) applies for the interpretation of this claim as it applies for the interpretation of an Act of Parliament. * .I* i-I tat. * S a a *,*aS4 *4d** * a * * * b * e S * S I * VS