VON HOLST, Hans (Kårevägen 12, Djursholm, S-182 66, SE)
WIKANDER, Jan (Ytterbyvägen 2, Vaxholm, S-185 94, SE)
VON HOLST, Hans (Kårevägen 12, Djursholm, S-182 66, SE)
WIKANDER, Jan (Ytterbyvägen 2, Vaxholm, S-185 94, SE)
CLAIMS
1. A finger giove, e.g. for use in strengthening a gripping movement executed with one or more fingers of a human hand enclosed in the gfove, wherein the glove comprises giove fingers and a palm, characterized in that the glove further comprises:
- for at least one glove finger (4a - 4c), artificial tendons (1a - 1c) which extend along the inside of the glove and has on each side of said giove finger such an artificial tendon (1a - 1c) running through ducts (3a - 3c) fixed to the sides of the glove finger,
- a yoke (6a - 6c) fitted in the tip of said at least one glove finger (4a - 4c) and designed to surround the tip of a finger enclosed in the giove finger (4a - 4c), and
wherein the artificial tendons ( 1 a - 1 c) of a glove finger are fixed to or slidingiy connected to said yoke (6a - 6c), whereby a pulling force exerted on the artificiai tendons of a glove finger bends the finger enclosed in the glove finger (4a - 4c) inwards towards the palm.
2. The finger glove according to claim 1 , wherein the giove comprises a rigid support (5) at the palm.
3. The finger giove according to claim 2, wherein one of: the paim of the giove, the support (5); for at least one glove finger (4a ~ 4c), includes a guide (2a - 2c) for guiding said artificial tendons to said at least one glove finger (4a - 4c).
4. The finger glove according to claim 3, wherein said guide (2a - 2c) comprises at least one of: a sleeve, a guide roiier, a guide pin, a ring, an eye.
5. The finger glove according to claim 1 , wherein said yoke (6a-βc) is shaped to accommodate the tip of a human finger and takes the form of one of the following components: a socket surrounding the fingertip, a bonnet for the fingertip, said artificial tendon (1a~1c) in itself, a flattened portion of said artificial tendon (1a-1c) in itself. 6, The finger giove according to claim 5, wherein fastening points of said artificial tendon (1a-1c) to the yoke (6a-6c), in cases where the iatter takes the form of a bonnet or socket, are situated at the sides of the glove finger (4a-4c) and close to the inner side of the glove finger.
5
7, The finger glove according to ciairn 3, wherein at least one of:
- said artificial tendons (1a-1c), said guides (2a-2c), said ducts (3a-3c) is situated between an outer and an inner layer of the giove.
10 8. The finger glove according to any of the preceding claims, wherein said palm support (5) takes the form of a supporting plane for said guides (2a-2c) and where a guide (2a-2c) for guiding the artificial tendons (1a-1c) to a giove finger (4a-4c) is fixed close to the base of each of the glove fingers (4a-4c) being equipped with artificial tendons (1a-1c).
15
9. The finger glove according to any of claims 2 to 7, wherein the artificial tendons (1a~1c) are surrounded by a wire socket (7a-7c) provided with an end sleeve (8a- 8c) fixed to the palm support (5).
20 10. The finger glove according to claim 1 , wherein said ducts (3a - 3c) are formed as one of: tubes, channels, grooves, and said ducts being one of: a) continuous and flexible, b) interrupted at the joints of a finger.
11. A system for strengthening a gripping movement performed with one or more 25 fingers of the human hand enclosed in a giove, utilising the glove of claim 1 , characterized in that the system comprises:
- a force detecting sensor (12a-12c) situated on the inside of the glove finger (4a~ 4c) arranged to detect a force between a finger enclosed in the giove finger (4a-
30 4c) and a contact surface applied to said finger,
~ the artificial tendons (1a-1c) for a glove finger (4a-4c) being connected to at least one actuator (10a-10c),
- a control unit (19) arranged to cause said at least one actuator (10a-10c) to exert a pulling force on the artificial tendons (1a-1c) of said at least one glove
3 S finger (4a-4c) on the basis of a force detected by the force detecting sensor (12a-
12c), whereby a finger enclosed in said at least one giove finger (4a-4c) is caused to bend, as the enclosed finger balances pushing forces which occur along the finger from the puiiing force in said artificial tendons.
12. The system according to claim 11 , wherein the control unit (19) is adapted to cause an actuator (10a-10c) to exert a pulling force on the artificial tendons (1a-
5 1 c) of at least one glove finger (4a~4c).
13. The system according to claim 11 , wherein the control unit (19) is adapted to cause at least one actuator (10a~10c) to exert a puiiing force on the artificial tendons (1a~1c) of only one glove finger (4a~4c).
10 14. The system according to claim 11, wherein the control unit (19) is adapted to cause an actuator (10a-10c) to exert a puiiing force on only the artificial tendons (1a-1c) connected to the glove finger (4a-4c) on the inside of which the force detecting sensor (12a-12c) which detects said force is situated.
15. The system according to claim 11 , wherein said force detecting sensor (12a-12c), 15 said actuator (10a-10c) and the control unit (19) are comprised in a feedback loop (11 ), whereby the control unit (19) itself comprises an electronic circuit (13) with a processor (14) programmed with a transmission function F.
16. The system according to any one of claims 11 to 15, wherein said force detecting sensor (12a-12c) measures the whole or part of the force which occurs between
20 said finger and said contact surface.
17. The system according to ciaim 15, wherein the detected force is scaled by a scale factor in the transmission function F and is converted to a reference force for said controlled actuator (10a-10c).
18. The system according to ciaim 17, wherein a variator (15) connected to the 25 electronic circuit (13) is used for setting the scale factor.
19. The system according to any one of claims 15, 17 and 18, wherein the transmission function F controls the setting of puiiing force to the respective glove finger (4a-4c) via the actuator (10a~10c).
20. The system according to any of claims 11 to 15 and 17 and 18, wherein an
30 actuator (10a-10c) takes the form of an electric motor (16a-16c) connected to a winding or linear device for the artificial tendons (1a~1c). |
Strengthening glove
TECHNICAL FIELD
The present invention relates to a glove intended to be worn by a human hand and be used for strengthening a gripping movement executed by one or more fingers of the hand.
STATE OF THE ART
A human with normal functions finds it quite natural to be able to grip an object with the hand and hold the object by desired and appropriate force between the fingers and the object for as iong a time as desired. Where a person's gripping movement with a hand does not have sufficient force, such a gripping movement may be found to be impossible or aimost impossible to execute. Examples of cases where muscular strength is not sufficient for such gripping movements include elderly persons with muscle weakening and persons being rehabilitated after, for example, brain injury. The same problem may also affect persons who have certain types of chronic conditions, e.g. rheumatism. Other examples of situations where it may be advantageous or necessary for persons to increase the muscular force which the hand can apply to an object in a gripping movement include, for example, astronauts or manual workers in certain situations.
Quite little has been done historically to use technical aids for strengthening the muscular force of persons who cannot manage to execute the aforesaid hand grip. An example of a closely allied situation is where a person completely lacks a hand, in that case there are plenty of different mechanical solutions in the form of prostheses that can perform gripping movements in a variety of ways.
US specification 4084267 refers to an example of a drive device for an orthosis, i.e. an external aid for imparting equivalents of muscular forces to the fingers of a human hand. That specification refers to cables which are pulled on the upper and/or inner sides of the fingers.
An article entitled "The Exoskeleton Glove for Control of Paralyzed Hands"; P. Brown, D. Jones, S.K. Singh; 1993 IEEE, pages 642-647 concerns a proposal for an external skeleton for a giove for a paralysed hand. That external skeleton is constructed mechanically and forms a kind of loadbearing skeleton round the hand.
Another article, entitled "An Anthropomorphic Hand Exoskeieton to Prevent Astronaut
Hand Fatigue during Extravehicular Activities"; B.L. Shields, J.A. Main, S.W. Peterson, A.M. Strauss; 1997 IEEE, pages 668-673 describes a device, likewise an example of a mechanical external skeleton for a hand, specificaiiy intended to increase the power of muscular movements during work involving the fingers in circumstances where their S muscles soon tire.
The two articles cited refer to examples of mechanical skeletons made up of ioadbearing units, which always renders the skeletons clumsy and unusable for the kinds of need described above.
A further reference to prior art is made by citing document US2008/0094989. in this 0 specification an example is disclosed, wherein fingers are actuated by cords running in sheaths along the finger. One cord for each finger is proposed for each finger joint in order to extend the finger and one cord along the inside of the finger to flex it. It is designed to control individual joints, thereby requiring one actuator for extending each joint and one for flexing it. Hence many actuators are needed when a number of fingers 5 are actuated. The purpose is to appiy motions to the joints not to apply forces to the grip performed by the fingers.
Another reference is made to document NL 7014761, wherein a method for actuation of the finger joints of a prosthesis, or a hand, is proposed. Only the closing of the fingers are actuated, while opening of the hand is made by springs. Each finger is 0 actuated by one cord running on the inside of the finger, Only one actuator is therefore necessary for putting torque to ail three joints of the finger, Such a configuration of a device when the number of joints is larger than the number of actuators is caiied under- actuation. A disadvantage of the design proposed in NL7014761 , if applied to a human hand, is that the distance between the joints of the finger and the cord is more or less 5 fixed to the distance from the joint to the skin on the inside of the finger. For under- actuation to perform weil the orthogonal distance between the cord and the joint should increase with the distance from the fingertip. For example, if the finger is to apply forces only at the fingertip, then the orthogonal distance should increase lineariy and if the forces should be evenly distributed over the finger length, the orthogonal distance should increase by the square of the distance from the fingertip.
An object of the present invention is to propose a solution to the disadvantages of the state of the art.
DESCRIPTION OF THE INVENTION According to an aspect of the invention a device with the characteristics according to
the attached claim 1 is presented.
Further embodiments of the invention are indicated in the dependent ciaims,
Said aspect of the invention refers to a giove provided with fingers, hereinafter calied a finger giove, which in one aspect of the invention forms a part of a system used to strengthen muscular forces initiated in a gripping movement using the fingers of a human hand wearing the strengthening giove. The glove uses the fingers of the hand wearing it to balance the pushing forces which occur aiong a finger from the forces in the artificial tendons which are adapted to effecting the desired strengthening.
The finger glove is provided intemaliy or in an intermediate layer with cords made of a suitable material which are intended to serve as said artificial tendons, expression "tendon" being hereinafter used for these cords.
BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 depicts the finger glove according to an embodiment of the invention in a plan view looking towards the palm of a hand enclosed in the giove but with all the constituent materia! of the glove omitted for the sake of ciarity.
Fig. 2 shows the same as Fig. 1 but as seen from the side of the hand.
Fig, 3 is a perspective view of a hand provided with the glove intended to strengthen a gripping movement, with the actual glove material omitted and with a schematicaily illustrated actuator based on signals from a depicted sensor.
Fig. 4 depicts schematically a feedback loop with an actuator for the glove used for strengthening a gripping movement with any of the fingers of a hand.
EMBODIMENTS
A number of embodiments of the invention are described beiow with reference to the attached drawings.
The strengthening giove according to the invention is most simply illustrated in Fig. 1 , where the finger glove is worn by a human hand but the actual glove to which the mechanical components are fitted is omitted to render the diagram more self- explanatory. The actual giove and its design are therefore not illustrated in the diagram, since the finger glove's design may of course vary in countless ways. For example, an already available glove, e.g. a sports glove, a golf glove or some type of
anatomical glove, may be used, but a special giove is preferably made specif icaliy for the purpose to suit the particular requirements of the finger glove user or a patient.
As previously mentioned, the finger glove is, in one embodiment of the invention, a component of a system here referred to as a strengthening giove. This strengthening giove comprises not only the finger giove but aiso:
- a force detecting sensor for each assistabie glove finger,
- an actuator to impart a pulling force to the artificial tendons so that designated fingers of the giove bend inwards towards the palm of the hand and can thus execute a gripping movement,
~ a feedback ioop comprising an electronic circuit with a transmission function which causes a motor in the actuator to impart a pulling force to the artificial tendons in response to signals from a sensor and to parameters set in the transmission function.
The expression "giove finger" hereinafter means a finger of the glove which is intended to accommodate a finger of the hand which wears the glove. It thus means a glove finger equipped to strengthen the muscular force of said finger, and the characteristics of said giove finger apply to aii the glove fingers covered by said strengthening. It may thus happen, for example, that only three giove fingers are equipped as described, but four or five fingers may be configured similarly.
Fig, 1 depicts the cords which serve as artificial tendons with reference notations 1a to 1 c. For the sake of clarity, the diagram shows oniy three of the glove's fingers equipped with artificial tendons, viz. the glove fingers corresponding to the thumb, index finger and middle finger of a hand, it is of course possible for ail of the fingers to be provided with corresponding devices as herein described for strengthening of muscular forces during finger movements, in which case all of the components involved in the system might, instead of referring to the three fingers referenced a-c in the present text, equally well comprise corresponding components referenced a-e if al! five fingers are equipped with strengthening according to the aspect of the invention. The artificial tendons 1a-1c run through guides 2a, 2b, 2c and ducts 3a, 3b, 3c which are all fastened in the giove. The purpose of a guide is to direct and link, in a low friction way, a tendon of a specific finger from its extension across the paim of the hand into a proper fine along said specific finger. The guide 2a, 2b, 2c can include any member from: a sleeve, a guide roller, a guide pin, a ring, an eye. As illustrated in the diagram, a guide 2a, 2b, 2c is provided for each of the respective glove fingers, whereby two tendons 1a-1c, intended to bend a particular giove finger, are adapted to passing
Q
through the same guide 2a, 2b, 2c to the particular giove finger, the guide 2a, 2b, 2c being situated close to the base of that giove finger. Thus, for example, the guide 2b is situated close to the base of the giove finger 4b which corresponds to the index finger of the human hand. The artificial tendons 1b dedicated to acting upon the glove's index finger 4b run through said guide 2b and on along this giove finger through the ducts 3b. The ducts 3a, 3b, 3c are situated at the sides of the respective glove fingers and preferably ciose to the inner sides of the giove fingers. Accordingly, the artificial tendons 1a~1c will run along the sides of the giove fingers and, as mentioned, close to their inner sides.
The artificial tendons 1 a-1 c comprise pairs of tendons each on their respective side of a giove finger with a view to achieving lateral equilibrium of moments when a pulling force is applied to the tendons pertaining to a particular finger of the glove. The ducts and the guides are also so disposed that the tendons run at a certain perpendicular distance from the joint axes of a finger in order to apply a suitable bending moment to the finger. Said distance is greater close to the palm of the hand than further out from the palm, it should also be noted here that the giove fingers 4a~4c could be equipped with cords corresponding to artificial tendons which straighten the giove fingers after a gripping movement that has involved glove fingers. However, during a human hand's gripping movement, i.e. when a gripping movement about an object has been effected and completed, no specific hand muscles are usually invoived in causing the fingers to revert to a straight position.
For good structural stability, the guides 2 are fastened to a rigid support 5 which covers a large proportion of the glove's equivalent to the paim of a hand. The design of the palm support 5 may vary, partly depending on which fingers of a hand for which the glove is intended are to be provided with strengthening, and it is of course possible for the support to be designed individually, i.e. adapted to the person who is to use the giove. The support is intended to serve as a substrate for fixing the guides 2a~2c so that they can guide the artificial tendons, i.e. hold said tendons ciose to the surface of the hand and ensure that two tendons for each finger are guided to leaving the palm of the hand at a point close to the base of the respective finger.
The palm support 5 is also a force opposing component for forces imparted via the artificial tendons 1a-1c. The artificial tendons 1a~1c are surrounded by wire sheaths 7a-7c terminated by end sleeves 8a~8c. The respective end sleeves 8a-8c are fixed to the palm support 5 in order to transmit force from corresponding tendons 1a-1c to the palm support 5 when a pulling force acts upon said corresponding tendons, i.e. the palm support 5 counteracts forces from the tendons.
Mountings 9a-9c may aiso with advantage be attached to the palm support 5. The purpose of these mountings 9a~9c is to guide the tendons 1a-1c between the end sleeves 8a~8c and the guides 2a-2b in order to provide the tendons with a predetermined curvature in this region, thereby preventing the tendons from assuming an unsuitable path or buckling to excessively sharp angles.
The palm support 5 need not be a separate unit if the corresponding region of the glove is made rigid so that the paim support can be integrated with the glove.
To further ensure that it abuts close to the palm of the hand, the support 5 may preferably be so configured that it has an extension which wraps round the hand, i.e. so that between the thumb and the index finger it is wrapped around the metacarpus and reaches a suitable distance onto the back of the hand between the thumb and the index finger. Further guides for guiding the artificial tendons may be attached along the palm support 5. The palm support 5 is also with advantage made of rigid plastic and may also comprise open areas.
The glove according to the aspect of the invention has, in a glove finger 4a-4c provided with strengthening, a yoke 6a-6c disposed at the tip of the glove finger to surround a tip of the enclosed finger or abut the tip of the finger. The purpose of the yoke is to ensure that when the artificial tendons 1a-1c are connected to said yoke 6a-6c the result is equivalent to the fastening of natural tendons to the outermost fingerbone. The yoke is therefore intended to serve the purpose that when the artificial tendons, e.g. the tendons 1b, pull on the yoke 6b, the enclosed fingertip will cause the finger 4b to bend, in this case the index finger. The fact that the artificial tendons also run through ducts 3a-3c at the side of the fingers and close to the inner sides of the fingers causes the finger in the glove to effect a gripping movement which resembles the natural finger's pattern of movement.
The yoke 6 may be configured in various different ways. Thus it may take the form of a bonnet which covers the actual fingertip of an enclosed finger, with fastenings attaching the artificial tendons 1a-1c to the sides of the bonnet. The yoke 6 may also, according to the preferred embodiment, be formed as a socket surrounding the fingertip on the upper side and on the sides or, alternatively on the upper side and every side round the fingertip. In an embodiment in the form of a socket, the yoke has well-situated fastening points at the sides of the socket furthest in towards the hand and close to the inner side of the finger As variants of these embodiments, the yoke may, in the simplest case, take the form of the actual cord which constitutes the artificial tendon 1a-1c, where the latter runs round the actual fingertip and is comparable to a yoke,
thus rendering fastening points superfluous. In such an embodiment, the artificiai tendon may be flattened at the end of the tip of the finger. According to different configurations the tendons may be fixed in reiation to its corresponding yoke or the tendons may be siidingly connected to its corresponding yoke, whereby the tendon may run across the yoke in a sliding movement in reiation to the yoke.
Where the yoke 6 takes the form of a bonnet or socket, it is preferably made of plastic material, but some other material such as metal or a composite is certainly usabie. The constituent materia! of the yoke 6 may aiso take the form of a) continuous covering materiai, b) perforated materia!, c) mesh materia!, d) material according to any of a) to c) but comprising open areas, it is also advantageous that the materiai of the yoke be reinforced, e.g. by meta! wires, glass fibres or equivalent, particularly round the portions of the material which are intended to serve as fastening points. In this embodiment it is possible for the yoke to be made by moulding to fit a specific user.
Different portions of the glove are made of different types of material. Most portions are made of flexible materia! to provide good comfort for an enclosed hand. Other portions, e.g. parts of the upper side of the glove fingers, are made of materiai which is rigid in at least one direction (perpendicular to the longitudinal direction of the finger). Further portions of the glove where rigidity of materiai may be required are round the palm support 5. The material is preferably permeable to moisture, so that a wearer of the glove can wear it for long periods of time without problems. Parts in the form of artificial tendons 1a-1c, guides 2a~2c, ducts 3a-3c, the palm support 5 and the yoke 6 may all be situated on the inside surface of the glove. Of these components, at ieast the palm support 5, the ducts 3a-3c and the yoke 6 are in that case fixed to said inside surface of the glove. In an alternative embodiment, the glove comprises at least one outer layer and one inner layer, in which case ail or at least some of the components listed in this paragraph are placed between said inner and outer layers.
The materiai constituting the glove comprises in whole or in part a) continuous covering material, b) perforated material, c) mesh material, d) materiai according to any of a) to c) but comprising open areas.
The ducts 3a-3c fixed along the sides of the glove fingers take with advantage the form of tubes, channels or grooves fixed along the glove fingers. The principle is that the artificial tendons 1a-1c are guided along the glove fingers. Alternatively, sewn ducts being integrated with the glove itseif may be used. It is necessary that the artificiai tendons 1a-1c be provided with the possibility of bending, at least between said ducts, and that the length of the artificiai tendons along the glove finger can be shortened and
lengthened. The ducts could be continuous and made of a flexible material or if stiff tubes, channels, grooves or the like are used, the ducts must be interrupted at least at the joints of the finger. Where tubes or the like are used, the materia! is with advantage characterised by iow friction, e.g. PTFE.
The artificial tendons 1a-1c are with advantage made of a low-friction easily bendabie material, e.g any of the following materials: nylon, steel, Dynema, lined Kevlar.
The execution of a gripping movement with a finger inserted in a glove finger is described below with reference to Fig. 4, which illustrates a feedback loop 11 with five fingers equipped with strengthening, despite the fact that functioning with only three activated fingers is described in the above text. In the example depicted, the sensors from ail five glove fingers are connected in the feedback loop.
The cords constituting the artificial tendons 1a-1c lead to an actuator 10a- 10c for each pair of tendons, e.g. an actuator 10b for a gripping movement with the index finger. The actuators 10a-10c for the respective fingers are connected to and controiled via a feedback loop 11.
A force detecting sensor 12a-12c is situated on the inside of the glove finger 4a~4c. Said sensor 12a-12c measures the whole force or parts of the force occurring between the finger and an object which is gripped by the finger enclosed in the glove.
The force detecting sensor 12a~12c forms part of the feedback loop 11 , which also comprises an electronic circuit 13 itself comprising a processor 14 programmed with a transmission function. The force measured by the sensor 12a-12c for a certain finger, e.g, 12b for the index finger, is scaled and converted to a reference force for said finger's actuator 10b. The force with which the actuator 10b then causes said finger to bend inwards as a result of being caused by the processor 14 to act upon the artificial tendons, in this case the tendons 1b, by applying a pulling force, results in increased force on the sensor 12b, so-caiied positive feedback. An appropriate scale factor results in strengthening. The scale factor may be varied by means of a variator 15, e.g. a potentiometer, connected to the eiectronic circuit 13. The feedback described may for example be effected by means of a microcontroi unit. Feedback as above is an example of known technology and is not further described here. It should also be mentioned that the number of force detecting sensors per glove finger may be one or more along the inside of the giove finger. The expression "a sensor" may therefore be interpreted as meaning that the sensor may comprise a plurality of units, it should further be mentioned that the force measured by a sensor is the whole or part of the force, which a finger applies to a contact surface which may be an object which is to be
gripped by the hand, but the contact surface may as well be the inside of a yoke, which has a wall (such as a socket wai!) such that the sensor 12a - 12c is situated between this wall and the finger,
Where the yoke δa~6b takes the form of a socket surrounding a finger on every side, the feedback ioop may be configured in an alternative way, whereby the force sensor 12a~12c detects, as previously mentioned, the force which the glove wearer's finger actively exerts upon the yoke, but none of the force which the actuator 10b exerts on the yoke. After filtering and scaling, this detected force can then be used as the actuator's reference force. The problems which may arise in positive feedback are in this case thus avoided.
The performance (exactness of response) of the giove can be improved by introducing an inner control loop for each tendon. This control loop would use tension measurement of the artificial tendon to improve the exactness of the applied force. The tensions can be measured at the actuator (and be an inherent part of the actuator} but rather as close as possible to the yoke in order to reduce the error in tension because of friction. One possible alternative of measuring is inside the palm support, another is in the yoke.
According to an embodiment, an actuator 10a-10c may be connected to the artificial tendons 1a~1c, which are connected to more than one glove finger 4a-4c. According to another embodiment, a plurality of actuators may be connected to the artificial tendons of one and the same giove finger, thereby making it possible to refine the control of the glove finger,
A contra! unit 19 may be adapted to causing the actuators 10a-10c to exert a pulling force on the artificial tendons 1a~1c of only one giove finger 4a~4c, e.g. the control unit may cause an actuator to bend, for example, an index finger inserted in the glove's equivalent of an index finger. The control unit may also be adapted to causing an actuator to bend more than one glove finger containing fingers.
According to an alternative embodiment, an actuator 10a-10c is connected by artificial tendons 1a-1c to only one giove finger 4a-4c.
According to a further embodiment, the control unit 19 is adapted to causing an actuator 10a~10c to exert a pulling force on only the artificial tendons 1a- 1c connected to the giove finger 4a-4c on the inside of which the force detecting sensor 12a-12c which detects said force is situated.
The actuators may take the form of an electric motor with a gear connected to a winding device, which may for example be a cord reel 18a~1δc on which the artificial tendon is wound. The eiectric motor may, as weii, be connected to a iinear device known in the art, such as a baii screw, According to an example, a sensor 17b situated in the actuator 10b detects the pulling force in the artificial tendons 1b connected to the respective finger. This detected force is used for closing the interna! feedback loop, which is guided towards a defined set-point, i.e. controlled by the defined scale factor. Fig. 4 depicts five actuators. This should not be interpreted as meaning that the respective actuators are connected by the artificial tendons 1a-1c to corresponding glove fingers 4a-4c. The connection of actuators to giove fingers may be effected in various alternative ways, as mentioned above.
Batteries 18 provide the actuators 10a~10c and the electronic circuit 13 with energy. Said components, electronic circuit 13, processor 14, potentiometer 15. are preferably enclosed in a purpose-made box, here referred to as the control unit 19 and situated with advantage on the forearm, in which case the artificial tendons can with advantage be arranged to be concealed between the glove and the contra! unit 19. Figs. 1 and 2 do not show the line which carries signals from the force detecting sensor 12a-12e to the control unit, in Fig. 3, said line is depicted as ref. 20.
Where the yoke 6 takes the form of a bonnet or socket, the tendons may am round the whole yoke 6, thus rendering fastening points irrelevant and resulting in the forces being better distributed and possibly allowing sideways movement of the finger.
The following are a number of further embodiment variants:
The ducts 3a~3c are made of such material that they can be allowed to run continuously all the way along the glove fingers, which means that they may also have a bellowsϋke structure so that certain sections can change length, in this iatter case, the ducts may also be allowed to run al! the way from the guides 2a-2c on the palm support 5 to the yokes 6 on the respective fingers.
The ducts 3a-3c may be sewn into the glove.
Strengthening may be provided for at least one finger in the glove. If for example the thumb of the natural hand is fixed, e.g. by being encased in piaster, a sufficiently good aid to being able to execute gripping movements during a rehabilitation period takes the form of a glove which oniy provides strengthening for the index finger's muscles.
To reduce friction between the tendons 1a~1c and the palm support 5, the mountings
9a-9c may be replaced by e.g. bail or rolling bearings.
All of or any desired pair of the artificial tendons, e.g. 1 b for the index finger, may be replaced by such a tendon which is spiit at the support 5 into two portions which proceed further as in the examples previousiy referred to.
The actuators 10 may be situated in the actual paim.
In an embodiment when the control of the movements of the glove is made with a microcontroller unit an interface to the user can be enhanced by use of a display. Further the microcontroiier can be connected to an external computer to make it easier to manipulate controi settings. The connection can aiso be used for retrieving logs of usage. The logs can for example be sensor readings or statistics of usage from longer periods of time.
DEFINITIONS
Finger means all of the hand's fingers, including the thumb.
A finger is defined here as having four sides, the upper side of a finger being that which, when the hand is extended with the back side up, has a direction similar to the upper side (the back) of the hand, the inner side being the side of the finger which can be bent in towards the palm, and the lateral sides referred to simply as the finger's sides.