Kinematical chain for assisting the motion of a spherical joint

Abstract

A kinematical chain (100) for assisting a spherical motion of an anatomical joint (200) of a finger of the hand (210) of a user, said anatomical joint (200) having centre of rotation P and being arranged for allowing a relative motion of a finger of the hand (210) with respect to a portion of hand (220) of the user, said finger of the hand (210) defining a longitudinal direction δ. The kinematical chain (100) comprises a first rotational joint (110) engaged to the finger of the hand (210) and to a first connection link (115), said first rotational joint (110) arranged to provide a relative rotation α between the first connection link (115) and the finger of the hand (210) about a rotation axis x coincident with the longitudinal direction δ. The kinematical chain (100) also comprises a third rotational joint (130) engaged to the portion of hand (220) and to a second connection link (125), said third rotational joint (130) arranged to provide a relative rotation γ between the second connection link (125) and the portion of hand (220) about a rotation axis z integral to the portion of hand (220). The kinematical chain (100) comprises then a second rotational joint (120) engaged to the first connection link (115) and to the second connection link (125), said second rotational joint (120) arranged to provide a relative rotation β between the first connection link (115) and the second connection link (125) about a rotation axis y. The rotation axes x, y and z intersect in a centre of rotation O, in such a way that the kinematical chain (100) allows a spherical motion of the longitudinal direction δ with respect to the portion of hand (220) about the centre of rotation P.

Claims

1. A kinematical chain (100) for assisting a spherical motion of an anatomical joint (200) of a finger of the hand (210) of a user, said anatomical joint (200) having centre of rotation P and being configured to allow a relative motion of said finger of the hand (210) with respect to a portion of hand (220) of said user, said finger of the hand (210) defining a longitudinal direction δ, said kinematical chain (100) comprising: a first rotational joint (110) configured to engage said finger of the hand (210) and to a first connection link (115), said first rotational joint (110) arranged to provide a relative rotation a between said first connection link (115) and said finger of the hand (210) about a rotation axis x coincident with said longitudinal direction δ; a third rotational joint (130) configured to engage said portion of hand (220) and to a second connection link (125), said third rotational joint (130) arranged to provide a relative rotation y between said second connection link (125) and said portion of hand (220) about a rotation axis z integral to said portion of hand (220); a second rotational joint (120) configured to engage said first connection link (115) and to said second connection link (125), said second rotational joint (120) arranged to provide a relative rotation R between said first connection link (115) and said second connection link (125) about a rotation axis y; said kinematical chain (100) characterized in that said rotation axes x, y and z intersect in a centre of rotation O, said kinematical chain (100) allowing a spherical motion of said longitudinal direction δ with respect to said portion of hand (220) about said centre of rotation P.

2. The kinematical chain (100), according to claim 1, further comprising an adjustment means configured to adjust the direction of said rotation axes x, y and z for bringing said centre of rotation O substantially at said centre of rotation P, in such a way that said kinematical chain (100) carries out said spherical relative motion between said longitudinal direction δ and said portion of hand (220) about said anatomical joint (200) without generating parasitic forces on said user.

3. The kinematical chain (100), according to claim 2, wherein said adjustment means (150) comprises at least two threaded fasteners (155) arranged to adjust its own height for adjusting the relative position between said centre of rotation O and said centre of rotation P of the anatomical joint.

4. The kinematical chain (100), according to claim 2, wherein said adjustment means (150) comprises a plate (156) comprising a first flat portion and a second flat portion orthogonal to each other, said first flat portion comprising a first couple of circular slots (156′) configured to allow a rotation of said third rotational joint (130) with respect to said portion of hand (220) about an axis orthogonal to said first flat portion, said second flat portion comprising a second couple of circular slots (156″) configured to allow a rotation of said third rotational joint (130) with respect to said portion of hand (220) about an axis orthogonal to said second flat portion.

5. A hand exoskeleton (300) for assistance to a spherical motion of a carpo-metacarpal joint (200) of the thumb of a user, said hand exoskeleton (300) comprising: the kinematical chain (100) according to claim 1, said finger of the hand (210) corresponding to the thumb of said user and said portion of hand (220) corresponding to the carpal portion of the hand of said user; a frame (320) configured to engage the back of the hand of said user; said hand exoskeleton (300) characterized in that said first rotational joint (110) is configured to engage with said thumb, and in that said third rotational joint (130) is configured to engage with said back of the hand by said frame (320).

6. The hand exoskeleton (300), according to claim 5, further comprises a thumb exoskeleton (310) configured to assist a flexion/extension motion of a thumb of said user; an index exoskeleton (330) integral to said frame (320) and configured to assist a flexion/extension motion of an index of said user.

7. The hand exoskeleton (300), according to claim 5, further comprising an exoskeleton for fingers (340) is configured to assist a flexion/extension motion of a middle finger, a ring finger and a little finger of said user.

8. The hand exoskeleton (300), according to claim 5, which further comprises an orthotic shell (350) configured to engage said hand exoskeleton (300) to the hand of said user, said orthotic shell (350) comprising: a plurality of interchangeable mesh straps arranged to wind said hand; two rotating joints (356) configured to allow a relative rotation between a first group (355′) of interchangeable mesh straps and a second group (355″) of interchangeable mesh straps in such a way to allow said orthotic shell (350) to fit to different anthropometric measures of said hand of said user.

9. The hand exoskeleton (300), according to claim 6, wherein said thumb exoskeleton (310) and said index exoskeleton (330) are configured to engage to the phalanxes, respectively, of said thumb and of said index by means of rings (360) wearable on said index and thumb fingers and having at least one pin (361) and further comprises a magnet (362) configured to engage with said thumb and index exoskeletons (310,330).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further characteristic and/or advantages of the present invention are more bright with the following description of an exemplary embodiment thereof, exemplifying but not limitative, with reference to the attached drawings in which:

(2) FIG. 1A shows a perspective view of a schematic embodiment of the kinematical chain according to the present invention;

(3) FIG. 1B shows a front view of the exemplary embodiment of FIG. 1A;

(4) FIG. 2 shows the kinematical chain of FIGS. 1A and 1B applied to the thumb of a user;

(5) FIG. 3 shows schematically the kinematical chain according to the present invention equipped with the adjustment means;

(6) FIG. 4 shows a possible exemplary embodiment of the kinematical chain according to the present invention equipped with adjustment means alternative to those of FIG. 3;

(7) FIG. 5 shows in a first perspective view an exemplary embodiment of the exoskeleton of hand according to the present invention;

(8) FIG. 6 shows in a second perspective view the exemplary embodiment of the exoskeleton of hand of FIG. 5;

(9) FIG. 7 shows an exemplary embodiment of the orthotic shell for fastening to the hand;

(10) FIG. 8 shows a perspective view of a second exemplary embodiment of the exoskeleton of hand according to the present invention;

(11) FIGS. 9A and 9B show two exemplary embodiments of the rings arranged to constrain the exoskeletons for fingers to the fingers.

DESCRIPTION OF A PREFERRED EXEMPLARY EMBODIMENT

(12) In the FIGS. 1A and 1B is shown a kinematical chain 100 for assisting a spherical motion of an anatomical joint 200, according to the present invention, applied to a generic finger of the hand.

(13) The anatomical joint 200 allows a spherical rotation of the finger of the hand 210 with respect to a portion of hand 220 about its own centre of rotation P.

(14) The kinematical chain 100 comprises a first rotational joint 110 engaged to the finger of the hand 210 and to a first connection link 115. The first rotational joint 110 is arranged to provide a relative rotation α between the first connection link 115 and the finger of the hand 210 about a rotation axis x coincident with the longitudinal direction δ defined by the finger of the hand 210 itself. In particular, the rotational joint 110 comprises an inner ring, integral to the finger of the hand 210, and an outer ring, integral to the connection link 115, and arranged to rotate with respect to the inner ring.

(15) The kinematical chain 100 comprises then a second rotational joint 120, engaged to the first connection link 115 and to a second connection link 125, and arranged to provide a relative rotation β between the two links about a rotation axis y.

(16) The kinematical chain 100 comprises then a third rotational joint 130, engaged to the portion of hand 220 and to the second connection link 125, and arranged to provide among them a relative rotation γ about a rotation axis z integral to the portion of hand 220.

(17) In particular, the rotation axes x, y and z intersect in a centre of rotation O coincident with the centre of rotation P of the anatomical joint 200.

(18) This way, the kinematical chain provides a spherical rotation of the rotation axis x with respect to the portion of hand 220, allowing to follow the spherical rotation of the finger of the hand 210 and to assist it, if the joints are active, without generating unwanted forces neither on the finger of the hand 210 itself, nor on the portion of hand 220, nor on the articulation.

(19) In FIG. 2 is shown the kinematical chain 100 of FIGS. 1A and 1B applied, in particular, to the thumb finger of a user, in such a way that the finger of the hand 210 corresponds to the thumb of the user and the portion of hand 220 corresponds to the palm of the hand of the hand of the user.

(20) With reference to FIG. 3, in an exemplary embodiment of the present invention, the kinematical chain 100 also comprises adjustment means 150 arranged to adjust the direction of the rotation axes x, y and z to assist the coincidence between the centre of rotation O and the centre of rotation P.

(21) In particular, the adjustment means 150 comprises four threaded fasteners 155 arranged to adjust its own height for adjusting the relative position between the intersection of the axes rotation x, y and z, i.e. the centre of rotation O, and the centre of rotating the anatomical joint P.

(22) In FIG. 4 a possible exemplary embodiment is shown of the kinematical chain 100 which can be fixed to an exoskeleton of hand, according to the present invention, equipped with adjustment means 150 alternative to those of FIG. 3.

(23) In particular, the first rotational joint 110 engages with the thumb by the orthotic shell 110′.

(24) In particular, the adjustment means 150 comprises a plate 156 located between the third rotational joint 130 and a frame 320 arranged to be integral to the portion of hand 220, i.e. With the carpal portion of the hand of the user. Such plate 156 comprises two flat portions located at 90° to each other, on which are provided, respectively, a first couple of circular slots 156′ and a second couple of circular slots 156″. The elongated holes 156′ and 156″ allow the third rotational joint 130 of the kinematical chain 100 of having a degree of freedom, respectively, in the angle of “yaw” and of “pitch” with respect to the orthotic shell fastening to the palm of the hand.

(25) Furthermore, the kinematical chain may comprise a variation means for adjusting the length of the connection link 115 and 125 and conform the kinematical chain to different measuring the hand (not shown in figure for the sake of clearness of drawing). For example, the link 115 and 125 can be telescopic or connected to the adjacent rotational joints by means of elongated holes that allow a relative translation.

(26) In the FIGS. 5 and 6 is shown, according to two different perspective views, a first exemplary embodiment of a hand exoskeleton 300 for assistance to a spherical motion of a carpo-metacarpal joint 200′ of the thumb of a user, according to the present invention. On this exoskeleton 300 the kinematical chain 100 of FIG. 4 is implemented in such a way that the finger of the hand 210 corresponds to the thumb of the user and the portion of hand 220 corresponds to the palm of the hand of the hand of the user.

(27) In particular, the exoskeleton 300 comprises, in addition to the kinematical chain 100, a frame 320 integral to the back of the hand of the user, in order to allow an engagement the third rotational joint 130 to the back of the hand.

(28) The exoskeleton 300 also comprises a thumb exoskeleton 310, which is adapted to assist the motion of flexion/extension of the thumb of the user, and an index exoskeleton 330 integral to the frame 320 and arranged to assist the motion of flexion/extension of the index of the user. In particular, the first rotational joint 110 engages with the thumb exoskeleton 310.

(29) Still with reference to an exemplary embodiment of FIGS. 5 and 6, the exoskeleton 300 also comprises an orthotic shell 350 arranged to engage the exoskeleton 300 itself to the hand of the user.

(30) In particular, in FIG. 7 the orthotic shell 350 comprises a plurality of interchangeable mesh straps arranged to wind the hand and two rotating joints 356 arranged to allow a relative rotation between a first unit 355′ of interchangeable mesh straps 355 and a second unit 355″ of interchangeable mesh straps 355. This way, the orthotic shell 350 can adapt to different anthropometric measures of the user.

(31) With reference to FIG. 8, in a second exemplary embodiment, the hand exoskeleton 300 also comprises an exoskeleton for fingers 340 arranged to assist a flexion/extension motion of the middle finger, of the ring finger and of the little finger of the user.

(32) In the exemplary embodiment of FIG. 9, moreover, the exoskeleton 300 comprises an alternative exemplary embodiment of the orthotic shell, much easier and cheap with respect to that of FIG. 7.

(33) In the FIGS. 9A and 9B two exemplary embodiments of the rings 360 are shown arranged to constrain the exoskeletons for fingers 310,330 to the fingers itself.

(34) In particular, in FIG. 9A the ring 360 comprises a magnet 362 arranged to avoid the disengagement between ring 360 and exoskeleton 310,330. The ring 360 also comprises a pin 361, which is adapted to enter a housing of the exoskeleton, and a step 363. The pin 361 and the step 363 synergically prevent the relative motion between the ring 360 and the exoskeleton 310,330, ensuring then the transmission of the motion of flexion/extension.

(35) In FIG. 9B the ring comprises, instead of the step 363, a second pin 361 that, with the first pin 361, prevents from a relative rotation.

(36) In both the exemplary embodiments of FIGS. 9A and 9B a band 364 is also comprised arranged to adjust the grip on the finger according to the measure of the finger itself.

(37) The foregoing description some exemplary specific embodiments will so fully reveal the invention according to the conceptual point of view, so that others, by applying current knowledge, will be able to modify and/or adapt in various applications the specific exemplary embodiments without further research and without parting from the invention, and, accordingly, it is meant that such adaptations and modifications will have to be considered as equivalent to the specific embodiments. The means and the materials to realise the different functions described herein could have a different nature without, for this reason, departing from the field of the invention. it is to be understood that the phraseology or terminology that is employed herein is for the purpose of description and not of limitation.