JPH1156885A - Motor-driven artificial hand - Google Patents

Abstract

PROBLEM TO BE SOLVED: To open/close fingers at high speed, to improve responsiveness, to reduce noises and further to simplify a structure by providing a crimping part having a supporting member for fingers, electromagnetic actuator for reciprocatively moving an output part, and link mechanism for opening/closing the fingers while being interlocked with the output part. SOLUTION: The main part of a motor-driven artificial hand is composed of a crimping part 1 for freely turnably supporting 1st and 2nd fingers 11 and 12 through a supporting member 13, linear actuator 2 as the electromagnetic actuator for linearly moving an output part 21, link mechanism 3 for opening/ closing the respective fingers 11 and 12 of the crimping part 1 while being interlocked with the linear motion of the output part 21, and wrist part 4 connected to the linear actuator 2. Therefore, any decelerating mechanism or transforming mechanism constituted in the conventional motor-driven artificial hand with a miniaturized motor as a driving source is unnecessitated. Further, since the output of the linear actuator 2 is directly transmitted to the link mechanism 3, the speed for opening/closing the fingers 11 and 12 is accelerated and responsiveness can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric prosthesis having a plurality of fingers that can be opened and closed.

[0002]

2. Description of the Related Art Conventionally, there has been provided an electric prosthesis in which a plurality of opposing fingers are opened and closed by a small motor. An electric prosthesis of this type is disclosed, for example, in Japanese Patent Application Laid-Open No. 55-99248. As shown in FIG. 5, the electric prosthesis disclosed in this publication includes a plurality of fingers 91a facing each other and each finger 9a.
A grip 91 having a support member 91b for rotatably supporting the base end of the base 1a, a prosthetic frame 92 for holding the support member 91b, a small motor 93 attached to the prosthetic frame 92, A speed reduction mechanism 94 connected to a motor 93; a conversion mechanism 95 for converting the rotational motion of the output of the speed reduction mechanism 94 into a linear reciprocating motion; Link mechanism 96 for opening and closing fingers 91a of portion 91
And

[0003] The speed reduction mechanism 94 transmits the driving force of a small motor 93 to an input gear 94 attached to a motor shaft 93a.
a and an intermediate gear (not shown) meshed with the input gear 94a to transmit the output gear 94b as an output unit. The rotation speed of the motor shaft 93a of the small motor 93 is set to, for example, 1/200. By reducing the speed, the driving torque is increased to secure the gripping force of the finger 91a. Further, the conversion mechanism 95 includes a drive shaft 95a coaxially and integrally rotatably mounted on the output gear 94b, and a moving nut 95b as an output portion screwed to a screw portion 95b of the drive shaft 95a. The moving nut 95b is linearly reciprocated by rotation of the drive shaft 95a in both the forward and reverse directions, and the linear reciprocating motion is transmitted to the finger 91a via the link mechanism 96. 91a can be opened and closed.

[0004]

Since the electric prosthesis transmits the output of the small motor 93 to the link mechanism 96 via the speed reduction mechanism 94 and the conversion mechanism 95, the opening and closing speed of the finger 91 is increased. In addition, there is a problem that the response to the opening / closing command is poor, and it is difficult to perform the fine movement opening / closing of the finger 91. Further, there is a problem that the drive noise of the speed reduction mechanism 94 and the conversion mechanism 95 is loud. In addition, there is a problem that the number of parts is large, the structure is complicated, and a large number of man-hours are required for maintenance. The present invention has been made in view of the above problems, and an object of the present invention is to provide an electric prosthesis which can open and close fingers at a high speed, has excellent responsiveness, has low noise, and has a simple structure.

[0005]

According to a first aspect of the present invention, there is provided an electric prosthesis having a plurality of fingers facing each other and a support member rotatably supporting a base end of each finger. And an electromagnetic actuator in which the output unit performs reciprocating motion, and a link mechanism that is directly connected to the output unit and opens and closes the fingers of the grip unit in conjunction with the reciprocating motion of the output unit. (Claim 1). According to the electric prosthesis having the above configuration, the reciprocating motion of the output portion of the electromagnetic actuator can be directly transmitted to the link mechanism to open and close the fingers of the grip portion. For this reason, a speed reduction mechanism and a conversion mechanism required in a conventional electric artificial hand using a small motor as a drive source are not required.

In the electromagnetic actuator, a magnet provided on an inner yoke and a coil provided on an outer yoke are combined, the inner yoke is provided so as to be movable in an axial direction, and the output section is provided on the inner yoke. Preferably, it is connected to a yoke (claim 2). In this case, since the movable side is the magnet side and the fixed side is the coil side, there is no need to configure the coil wiring and the like to be movable, and the configuration on the movable side can be simplified. For this reason, the inertia force on the movable side can be reduced, and the output section of the electromagnetic actuator can be finely moved with high accuracy.

The outer yoke of the electromagnetic actuator is
It is preferable that the frame also serves as a prosthetic frame for holding the support member (claim 3). In this case, there is no need to separately configure the prosthetic frame, so that the structure can be simplified accordingly. Also, replacement of the electromagnetic actuator is facilitated.

In the electric prosthesis, a lid made of a non-magnetic material may be detachably attached to an opening end of the outer yoke on the output side, and a support member for the grip portion may be attached to the lid. Item 4), in this case, by removing the lid from the outer yoke, the maintenance of the electromagnetic actuator becomes easier, for example, the outer yoke can be replaced.

In the electric prosthesis, a lid made of a non-magnetic material is detachably attached to an opening end of the outer yoke on the output side, and the support member of the grip portion is made of a non-magnetic material on the lid. In this case, the number of parts and the number of assembling steps can be reduced as compared with the case where the lid and the support member are separately configured. Further, the supporting member is also made of a non-magnetic material having the same specific gravity as the lid, such as an aluminum alloy, a magnesium alloy, and a synthetic resin, so that the weight can be reduced.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the electric prosthesis of the present invention will be described in detail. FIG. 1 is a front view showing an embodiment of an electric prosthesis according to the present invention, and FIG. 2 is a plan view thereof. This electric prosthetic hand has the first finger 11
The gripper 1 rotatably supports the second finger 12 by the support member 13, the linear actuator 2 as an electromagnetic actuator in which the output unit 21 performs a linear reciprocating motion, and the linear actuator 2 in conjunction with the linear reciprocating motion of the output unit 21. A main part is constituted by a link mechanism 3 for opening and closing the fingers 11 and 12 of the gripper 1 and a wrist unit 4 connected to the linear actuator 2.

The first finger 11 and the second finger 12 of the gripper 1 function as an index finger and a thumb, respectively.
One book and one second finger 12 are provided. The first finger 11 and the second finger 12 are provided so as to face each other.
a, 12a are separated from each other by the support
Is rotatably pinned. The distal end of the first finger 11 is bent toward the second finger 12, so that the distal ends of the fingers 11 and 12 can be brought into close contact with each other while the fingers 11 and 12 are close to each other. In addition,
A cover 14 made of a synthetic resin is attached to the tip of each of the fingers 11 and 12. The support member 13 is a double-legged member made of a lightweight metal such as an aluminum alloy and a magnesium alloy. The support member 13 is provided in a pair corresponding to each of the fingers 11 and 12, and each base 13 a is screwed to the first lid 22 of the linear actuator 2.

Referring also to FIG.
The outer yoke 24 is a cylindrical magnetic body, the first lid 22 for closing the opening end of the outer yoke 24 on the grip portion 1 side, and the opening end of the outer yoke 24 on the wrist portion 4 side. A second lid 23, an inner yoke 25 which is a magnetic material concentrically arranged inside the outer yoke 24, a coil 26 provided along the inner peripheral surface of the outer yoke 1, and an inner yoke 2.
5, an output portion 21 connected to one end of the inner yoke 25, and the inner yoke 25 supported movably in the axial direction in cooperation with the output portion 21. And a supporting shaft 28.

As shown in FIG. 4, the outer yoke 24 has a square cross section on the outer periphery and a circular cross section on the inner periphery. The outer yoke 24 also serves as a prosthetic hand frame for holding the support member 13 of the grip portion 1. Therefore, the structure of the device can be simplified as compared with a case where the prosthesis frame is separately configured and the linear actuator 2 is attached to the prosthesis frame, and the replacement operation of the linear actuator 2 is also facilitated. Each of the lids 22 and 23 is a flat plate having through holes 22a and 23a at the center, and the outer peripheral shape is a square that matches the outer periphery of the outer yoke 24. This lid 22, 2
Reference numeral 3 is formed of a synthetic resin such as an aluminum alloy, a magnesium alloy, and a fiber reinforced resin, and other non-magnetic materials. The inner yoke 25 is a columnar body having a through hole 25a in the center, and the inner yoke 25 is provided with the through hole 25a
A shaft 28 is introduced to the output unit 21 at the other end.
Is screwed.

A base end of the support shaft 28 is fitted into a through hole 23a of the second lid 23, and a middle part thereof is slidable through a slide bearing B1 into a through hole 25a of the inner yoke 25. It is inserted in. The output portion 21 is a shaft having a male screw 21a formed at a tip, and a middle portion of the output portion 21 is inserted into a through hole 22a of the first lid 22 in a sliding bearing B.
2 so as to be slidable. Therefore, the inner yoke 25 is movably supported in the axial direction by the outer yoke 24 via the output portion 21 and the first lid 22, and the support shaft 28 and the second lid 23, respectively.

The coil 26 comprises a first coil 26a on the first lid 22 side and a second coil 26b on the second lid 23 side. Each of the coils 26a, 26b has a lead wire L1, L
The current is supplied individually through 2. The magnet 27 includes a first magnet 27a provided at an end of the inner yoke 25 on the first lid 22 side and a second magnet 27b provided at an end of the inner yoke 25 on the second lid 23 side. Each of the magnets 27a and 27b is formed by arranging a plurality of magnet pieces that are polarized so that the inner peripheral side and the outer peripheral side have different polarities in a cylindrical shape, and each of the first magnet 27a and the second magnet 27b. And the inner peripheral sides of the first magnet 27a and the second magnet 27b have polarities different from each other. Also, the first magnet 27a
The second magnet 27b maintains a predetermined air gap between the first coil 26a and the second coil 26b, respectively.

In the linear actuator 2 configured as described above, when a current is supplied to the first coil 26a and the second coil 26b such that their adjacent ends have the same polarity, the magnet 27 is formed. The thrust based on Fleming's law is
The inner yoke 25 is moved by the reaction to the output portion 21.
And move in one axial direction. When a current is supplied to the first coil 26a and the second coil 26b so as to generate a magnetic pole opposite to the above, the output unit 21 moves in the opposite direction. Thus, the output unit 21
A linear reciprocating motion can be performed. The linear actuator 2 has the coil 26 on the fixed side and the magnet 27
Is movable, it is not necessary to configure the lead wires L1 and L2 to be movable, and the structure of the movable side can be simplified accordingly. Therefore, the inertia force on the movable side can be reduced, and the output unit 21 can be finely moved with high accuracy. Therefore, the fine movement operation of the fingers 11 and 12 becomes easy. Further, the support member 1 is attached to the first lid 22.
Since the outer yoke 24 needs to be replaced due to the life or damage of the coil 26, the outer yoke 24 is separated by separating the first lid 22 and the outer yoke 24. Maintenance can be facilitated, such as easy replacement.

The link mechanism 3 includes a linear actuator 2
Bracket 3 screwed into male screw 21a of output section 21
0, a pair of first links 31 whose base ends are rotatably connected to the bracket 34, and a base end 11a of the first finger 11, which is integrally formed with the first link 3
A second link 32 rotatably connected to the distal end of the first link;
One end is rotatably connected to the base end 12 a of the second finger 12, and the other end includes a third link 33 rotatably connected to the first link 31.
The link mechanism 3 is driven by the first
The finger 11 is rotated clockwise in FIG. 1, and the second finger 12 is rotated counterclockwise in FIG. 1, and the first finger 11 is rotated counterclockwise in FIG. By rotating the two fingers 12 clockwise, the fingers 11 and 12 are opened and closed.

The wrist section 4 has its wrist 41 screwed to the second lid 23 of the linear actuator 2. The wrist portion 4 is a portion that rotatably connects the grip portion 1 and the linear actuator 2 to a prosthetic arm to be attached to the body at a predetermined angle. The electric prosthesis is entirely covered with a decorative cover (not shown).

The electric prosthesis having the above configuration uses the linear actuator 2 as a drive source, and its output section 21 is directly connected to the link mechanism 3, so that it is configured as a conventional electric prosthesis using a small motor as a drive source. The need for a deceleration mechanism and a conversion mechanism is eliminated. Therefore, the structure can be simplified,
Its maintenance is also easy. Further, since the output of the linear actuator 2 is directly transmitted to the link mechanism 3, the opening / closing speed of the fingers 11, 12 can be increased.
For example, the opening / closing speed can be increased to about four times the conventional speed without increasing the size. Furthermore, since the response to the opening / closing command can be improved, the finger 1
Fine movement opening and closing of 1, 12 is also possible. In addition, almost no driving noise is generated.

The support member 13 of the gripper 1 may be formed integrally with the first lid 22 of the linear actuator 2 by a non-magnetic material. In this case, the first lid 22 and the support member 13 Can be reduced in number of parts and assembling man-hours as compared with the case where the components are separately configured. Also, the support member 13 is made of a non-magnetic material having the same small specific gravity as the first lid 22, such as an aluminum alloy, a magnesium alloy, or a synthetic resin, so that the weight can be reduced.

The electric prosthesis of the present invention is not limited to the above embodiment. For example, instead of the linear actuator 2, a rotary actuator whose output section performs a rotary reciprocating motion is used as the electromagnetic actuator. For example, various design changes can be made.

[0022]

As described above, according to the electric prosthesis of the first aspect, the reciprocating motion of the output portion of the electromagnetic actuator is
Since the finger of the gripper can be opened and closed by directly transmitting to the link mechanism, the reduction mechanism and the conversion mechanism required in the conventional electric prosthesis using a small motor as a drive source are not required. Therefore, the structure can be simplified, the maintenance thereof can be facilitated, and the opening / closing speed of the finger can be increased. In addition, since the response to the opening / closing command can be improved, the finger can be finely opened / closed, and the generation of noise is very small.

According to the second aspect of the present invention, since the movable side is the magnet side and the fixed side is the coil side, there is no need to make the coil wiring and the like movable, and the configuration of the movable side can be simplified. As a result, the inertia force on the movable side can be reduced. For this reason, the output part of the electromagnetic actuator can be finely moved with high accuracy, and the fine movement operation of the finger becomes easy.

According to the third aspect of the present invention, since the outer yoke of the electromagnetic actuator also serves as the artificial arm frame, the structure can be simplified and the electromagnetic actuator can be easily replaced.

According to the electric prosthesis of the fourth aspect, a lid made of a non-magnetic material is detachably attached to the opening end of the outer yoke on the output side, and the support member of the grip is attached to this lid. Therefore, by removing the lid from the outer yoke, maintenance of the electromagnetic actuator becomes easier, for example, the outer yoke can be replaced.

According to the fifth aspect of the present invention, since the lid of the electromagnetic actuator and the supporting member of the grip portion are integrally formed of a non-magnetic material, the lid and the supporting member are separately formed. Compared to the case, the number of parts and the number of assembly steps can be reduced, and the weight can be reduced.

[Brief description of the drawings]

FIG. 1 is a front view showing an embodiment of an electric artificial hand according to the present invention.

FIG. 2 is a plan view of the same.

FIG. 3 is a sectional view of a linear actuator.

FIG. 4 is a sectional view taken along the line IV-IV in the preceding figure.

FIG. 5 is a front view showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Grasping part 11 1st finger 12 2nd finger 13 Support member 2 Linear actuator 21 Output part 22 1st lid 23 2nd lid 24 Outer yoke 25 Inner yoke 26 Coil 27 Magnet 3 Link mechanism

Claims (5)

[Claims] A gripping portion having a plurality of fingers facing each other, a support member rotatably supporting a base end of each finger, an electromagnetic actuator in which an output portion reciprocates; An electric prosthetic hand, comprising: a link mechanism that is directly connected and that opens and closes the fingers of the grip section in conjunction with the reciprocating motion of the output section. 2. The electromagnetic actuator according to claim 1, wherein a magnet provided on an inner yoke and a coil provided on an outer yoke are combined, the inner yoke is provided so as to be movable in an axial direction, and the output section is provided. The electric prosthetic hand according to claim 1, which is connected to the inner yoke. 3. An outer yoke of the electromagnetic actuator,
The electric prosthesis according to claim 2, which also serves as a prosthesis frame for holding the support member. 4. A lid made of a non-magnetic material is detachably attached to an opening end of the outer yoke on the output side, and a support member of the grip portion is attached to the lid.
The described electric prosthesis. 5. A lid made of a non-magnetic material is detachably attached to an opening end of the outer yoke on the output side, and a support member of the grip portion is integrally formed on the lid with a non-magnetic material. The electric prosthesis according to claim 2, which is formed.