MOVING DEVICE FOR MOVING A HUMAN THUMB, HAND-EXOSKELETON AND METHOD OF GRASPING

Abstract

A moving device for moving a human thumb, in particular for moving the thumb between a resting position and a grasping position. A thumb bending section is adapted to at least partially move the thumb between a flexed position and an extended position. The thumb bending section has a gear unit for transforming a rotation of a rotation element, which is rotatably mounted to a housing, into an essentially linear movement between a translation element and the housing. The thumb bending section further has a first flexion spring mechanically connected to the translation element and adapted to be fixed with a first proximal end of the first flexion spring relative to a human thumb at a position in a proximal distance to the metacarpophalangeal joint or at a position between the metacarpophalangeal joint and the carpometacarpal joint.

Claims

1. A moving device to move a human thumb between a resting position and a grasping position, the moving device comprising: a thumb bending section adapted to at least partially move the thumb between a flexed position and an extended position, the thumb bending section comprising: a gear unit for transforming a rotation of a rotation element, which is rotatably mounted to a housing, into an essentially linear movement between a translation element and the housing; a first flexion spring mechanically connected to the translation element and adapted to be fixed with a first proximal end of the first flexion spring relative to a human thumb at a position in a proximal distance to a metacarpophalangeal joint or at a position between the metacarpophalangeal joint and a carpometacarpal joint; and a second flexion spring mechanically connected to the housing and adapted to be fixed with a second distal end of the second flexion spring to the human thumb at a position in a distal distance to the metacarpophalangeal joint or at a distal phalanx and/or a proximal phalanx of the thumb such that by operating the gear unit, a relative translational movement between the translation element and the housing is realized that causes a bending of at least one of the first or second flexion springs and as a result at least a partial bending of the thumb.

2. The moving device according to claim 1, wherein the first flexion spring and the second flexion spring are arranged essentially along a direction of the linear movement, and wherein the second flexion spring is mechanically connected to the housing in the direction of the linear movement on an opposite side of the mechanical connection of the first flexion spring to the translation element such that the first flexion spring and/or the second flexion spring are bendable by the relative translational movement and a flexion force and/or a flexion moment is applicable to the thumb fixed to the moving device.

3. The moving device according to claim 1, wherein the rotation element is a pinion and the translation element is a rack, wherein the pinion and the rack are adapted to intermesh such that the rotation of the pinion is transformable into the linear movement between the rack and the housing.

4. The moving device according to claim 1, wherein the mechanical connection between the second flexion spring and the thumb is realizable by a second fixation section that is fixable to a phalanx of the thumb or to a distal phalanx of the thumb, and wherein at least a translational degree of freedom of the second distal end along the direction of the linear movement is fixable by the second fixation section.

5. The moving device according to claim 1, wherein the second flexion spring comprises two springs or two leaf springs arranged essentially in parallel to each other such that a moment of inertia of the second flexion spring around an axis substantially perpendicular to the linear movement and substantially perpendicular to the plane in which the two springs are parallelly arranged is increased.

6. The moving device according to claim 1, wherein the fixation of the first flexion spring to the thumb is by a first fixation section, and wherein the first flexion spring is fixable by the first fixation section such that at least a translational degree of freedom of the first proximal end along the direction of the linear movement is fixed by the first fixation section.

7. The moving device according to claim 1, wherein the thumb bending section comprises a guide arranged between the fixation of the second flexion spring to the thumb and the housing, and wherein the guide is adapted to be fixed to the thumb such that the guide is adapted to guide the second flexible spring by essentially fixing all translational degrees of freedom and all rotational degrees of freedom of the second flexible spring except a translational degree of freedom in the direction of the linear movement.

8. The moving device according to claim 7, wherein the second flexion spring comprises a first section and a second section arranged along the axis of the relative translational movement on opposite sides of the guide, wherein between the guide and the second flexion spring a frictional resistance is realized such that the friction force acts against a force acting on the second flexion spring when the second flexion spring is moved in a relative translational movement, which leads to a deformation of the first section of the second flexion spring between the housing and the guide essentially before a deformation of the second section of the second flexion spring between the guide element and the fixation of the second flexion spring to the thumb occurs.

9. The moving device according to claim 1, wherein first flexion spring the thumb bending section comprises at least one spring arranged substantially in parallel to the first flexion spring and the second flexion spring, and wherein a distal end of the spring is fixed to the second distal end of the second flexion spring and a proximal end of the spring is fixed to the first proximal end of the first flexion spring and wherein the spring is supported on the housing.

10. The moving device according to claim 1, wherein the moving device comprises a thumb opposition section adapted to move the thumb between a resting position and an opposition position or a pad opposition position and/or side opposition position, wherein the thumb opposition section is pivotably connected to the thumb bending section by a pivot, and wherein the thumb opposition section comprises a feeder that is mechanically connected to the thumb bending section in a distance to the pivot such that when a feeding force with at least one force direction component substantially perpendicular to the direction of the linear movement is applied to the thumb bending section by the feeder, the thumb bending section rotates around the pivot and therefore a thumb fixed to the thumb bending section is movable at least in an abducted position.

11. The moving device according to claim 10, wherein the mechanical connection between the feeder and the thumb bending section is realized by a pivot joint, wherein an angle of a rotary movement of the feeder in relation to the thumb bending section is limited by a mechanical stop.

12. The moving device according to claim 10, wherein the feeder is a flexible spring or a bending spring.

13. The moving device according to claim 10, wherein the feeder is movably guided by a feeding element guide when moved to apply a feeding force onto the thumb bending section.

14. A hand-exoskeleton for moving at least one finger of a human hand, the hand-exoskeleton comprising a moving device for moving a human thumb according to claim 1.

15. A method of grasping an object, the method comprising: fixing a moving device according to claim 1 to the thumb of a human hand or a hand-exoskeleton is fixed to a human hand; placing an object between the thumb and the palm of the hand; and operating the gear unit such that the thumb is at least partially moved in a direction of the palm by at least partial bending such that forces act onto the object on essentially opposite sides.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0109] The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitive of the present invention, and wherein:

[0110] FIG. 1 shows an example of the moving device according to the invention,

[0111] FIG. 2 shows how a moving device according to the invention is fixed to the thumb of a human hand,

[0112] FIG. 3a shows a first state of the thumb opposition section,

[0113] FIG. 3b shows a second state of the thumb opposition section,

[0114] FIG. 3c shows a third state of the thumb opposition section,

[0115] FIG. 4 shows a first detail of an example of the moving device according to the invention,

[0116] FIG. 5 shows a second detail of an example of the moving device according to the invention,

[0117] FIG. 6 is an example of a hand-exoskeleton according to the invention, and

[0118] FIG. 7 is an example of the moving device according to the invention.

DETAILED DESCRIPTION

[0119] FIG. 1 shows an example of the moving device 1 according to the invention. The moving device 1 comprises a thumb bending section 10 adapted to move a thumb that is fixed to the thumb bending section 10 between an extended position and a flexed position.

[0120] In the distal direction 2, the thumb bending section 10 comprises a second fixation section 19 that is in the given example adapted to be fixed to a distal phalanx of a thumb. The second fixation section 19 is fixed to a second flexion spring 50 comprising in the given example two parallel leaf springs 24 and extending from the second fixation section 19 in proximal direction 3 to the housing 14 of a gear unit 11 to which it is fixed.

[0121] The second flexion spring 50 is divided in two sections 53, 54. The first section 53 is located between the housing 14 and the guide 23. The second section 54 is located between the guide 23 and the second fixation section 19. The guide 23 is adapted to guide the second flexion spring 50 when the second flexion spring 50 is moved by the gear unit 11 in distal direction 2. The second flexion spring 50 is mechanically connected to the gear unit 11 that is adapted to move the second flexion spring 50 as well as the first flexion spring 40.

[0122] The gear unit 11 comprises a rotation element 12, which is in the given example a pinion 13, and a translation element 16, which is in the given example a rack 17. The rack 17 and the pinion 13 are arranged and adapted to intermesh. Furthermore, the gear unit 11 comprises a housing 14 to which the pinion 13 is rotatably fixed.

[0123] The rack 17 is fixed to the first distal end of the first flexion spring 40 comprising one leaf spring 24. The first proximal end 41 of the first flexion spring 40 is fixed to the first fixation section 18, wherein the first fixation section 18 is adapted to fix the first proximal end 41 of the first flexion spring 40 in a position fixed relative to the thumb. The position of the first proximal end 41 of the first flexion spring 40 is essentially the position of the carpometacarpal joint of a thumb.

[0124] By operating the pinion 13 of the gear unit 11 the rack 17 is movable in proximal direction 3 which causes a bending or buckling of the first flexion spring 40. While the bending of the first flexion spring 40 occurs the restoring force of the first flexion spring 40 increases such that at a certain point the housing 14 moves in distal direction 2 which causes a bending or buckling of the second flexion spring 50, wherein, caused by a frictional resistance between the second flexion spring 50 and the guide 23, the first section 53 of the second flexion spring 50 is bent first and afterwards the second section 54 of the second flexion spring 50 is bent.

[0125] As shown in FIG. 1 below the second flexion spring 50 a spring 30 with a fourth flexion spring 70 is arranged. The fourth flexion spring 70 is via the second fixation section 19 fixed to the second flexion spring 50. The proximal end of the fourth flexion spring 70 is fixed to an outer housing 15, which is additionally adapted to guide the housing 14 when it is moved in distal direction 2.

[0126] Furthermore, the moving device 1 shown in FIG. 1 comprises a thumb opposition section 80 with a feeding element 82 that is pivotably fixed to the outer housing 15. The thumb opposition section 80 is rotatably connected to the thumb bending section 10 by a pivot 81, which is in one example a ball joint. By moving the feeding element 82 in the direction of the outer housing 15 a feeding force is applicable to the thumb bending section 10 such that the thumb bending section 10 is rotatable around at least one rotation axis of the pivot 81.

[0127] FIG. 2 shows how a moving device 1 is fixed to the thumb 112 of a human hand 110. It is shown that the second fixation section 19 is fixed to the distal phalanx DP, that the second section 54 of the second flexion spring is arranged above the interphalangeal joint IP, that the guide 23 is fixed to the proximal phalanx PP, that the first section 53 of the second flexion spring is arranged above the metacarpophalangeal joint MPC, that the gear unit 11 is arranged between the metacarpophalangeal joint MPC and the interphalangeal joint IP and that the first proximal end 41 of the first flexion spring 40 as well as the pivot 81 of the thumb opposition section is arranged above the carpometacarpal joint CPC. The feeding element that causes by a feeding force the rotation movement 86 around at least one rotation axis of the pivot 81 is not shown here. An arrow indicates the second relative translational movement 25 of the relative translational movement 21 that causes the bending of the second flexion spring.

[0128] FIG. 3 shows the function of the thumb opposition section 80 in three steps. FIG. 3a shows a first state of the thumb opposition section 80 in the resting position, in which a thumb to which the moving device is fixed is unflexed and adducted to the index finger. FIG. 3b shows a second state of the thumb opposition section 80 when the thumb to which the moving device is fixed is already in a position in which the thumb is an abducted position, in particular in a side opposition position. FIG. 3c shows a third state of the thumb opposition section 80 in which the thumb is in pad opposition position.

[0129] When the feeding element 82 is moved in the direction of the thumb bending section 10 a feeding force 83 is applied to the outer housing 15 to which the feeding element 82 is connected via a pivot joint 85. The feeding element 82 is guided by a mechanical stop 87. In the first state shown in FIG. 3a the feeding element 82 is in contact with a first stop element 91. The feeding force 83 of the feeding element 82 in combination with the pivot 81 causes that the thumb opposition section 80 is adapted to cause a rotation movement 86 of the thumb bending section 10. The comparison of FIG. 3a and FIG. 3b shows that a first rotation movement 94 around a rotation axis of the pivot 81 perpendicular to the plane of the figure is limited by the angle 85 enclosed by the first stop element 91 and the second stop element 92 of the mechanical stop 87.

[0130] By further applying the feeding force 83 to the thumb bending section 10 as it is shown in FIG. 3c, a second rotation movement 95 around the axis of the linear movement 20 is caused. To allow this second rotation movement 95 the feeding element 82 is designed as a flexion spring 88, in particular as a leaf spring 24.

[0131] FIG. 4 shows a first detail of an embodiment of the moving device 1. It can be seen that the second flexion spring 50 comprises two parallel springs, designed as leaf springs 24, which enclose an angle. The two leaf springs 24 are guided by the guide 23. The guide 23 therefore comprises two guiding holes 26, wherein each leaf spring 24 runs through a single guiding hole 26. In other words, the leaf springs 24 are movable relative to the guide 23 by sliding through the guiding holes 26. In the rear part of FIG. 4 the second fixation section 19 is shown.

[0132] Below the second flexion spring 50 a fourth flexion spring 70 is arranged, which comprises one leaf spring 24 in the given example. The leaf spring 24 of the fourth flexion spring 70 is guided by the guide 23 as well, which is not shown here in detail.

[0133] FIG. 5 shows a second detail of an embodiment of the moving device illustrating the bending of the second flexion spring 50 and the fourth flexion spring 70 according to the relative translational movement. Caused by the movement of the second flexion spring 50 in the direction of the second fixation section 19 the leaf spring 24 or leaf springs 24 of the second flexion spring 50 are bent. Because of the fixation of the fourth flexion spring 70 to the second fixation section 19 the leaf spring 24 of the fourth flexion spring 70 is bent as well. By the bending a flexion force and/or a flexion moment is applicable to a thumb that is fixed to the moving device.

[0134] FIG. 6 shows an embodiment of a hand-exoskeleton 100. The hand exoskeleton 100 comprises a driving unit 109 that is fixable to a human body by a harness 107. The driving unit is via an interface 90 which is adapted to be fixed to the dorsal side of the hand connected by a bowden cable 108 with the gear unit 11 of the moving device such that by the bowden cable 108 the pinion 13 can be rotated so that the rotation of the pinion 13 can be transferred into a linear movement between the rack 17 and the housing.

[0135] FIG. 7 shows another embodiment of the moving device 1 according to the invention. In particular FIG. 7 shows an interface 90 that is adapted to be fixed to the dorsal side of a hand. On the upper side of the interface 90 the feeding element guide 89 is shown that guides the feeding element 82 when moved in the direction of the thumb bending section 10. The feeding element 82 comprises a leaf spring 24. The feeding element 82 is mechanically connected to the gear unit 11, wherein the pivot joint, which realizes this rotatable connection, as well as the mechanical stop are not shown here. The gear unit 11 is arranged between the first flexion spring 40 and the second flexion spring 50. The first flexion spring 40 extends between the first fixation section 18 and the gear unit 11. The second flexion spring 50 extends between the second fixation section 19 and the gear unit 11. FIG. 7 also shows a third flexion spring 60. Furthermore, it is shown that the guide 23 is adapted to be fixed to the thumb by a strap 27.

[0136] The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims.