Hand model

Abstract

To provide a mechanism that preferably reproduces a movable range and a non-movable range of human fingers, and a mechanism that reproduces various expressions of the human fingers.SOLUTION: A hand model has a central member composed of a joint part and a metacarpal part. The joint part is composed of a first outside part and a first inside part. The first outside part rotatably accommodates the first inside part. The first outside part has at least one guide part. The guide part of the first outside part regulates rotation of one shaft around one rotation shaft among three rotation shafts of the first inside part.SELECTED DRAWING: Figure 1B

Description

[Technical Field]

[0001] The present invention relates to a hand model. [Background technology]

[0002] JP 2022-28002 A (Patent Document 1) is a background art in this technical field. This publication describes the following: "A hand joint structure of a doll body including a wrist 110 provided on an extension of a lower arm 80, a back of the hand 115 connected to the wrist 110, and a plurality of fingers 120 including a thumb 120A connected to the back of the hand 115, wherein the back of the hand 115 has a notch 131 and a protrusion 132 formed across the notch 131 on the side to which the wrist 110 is connected, and the wrist 110 is connected via a first ball joint 141 embedded in the protrusion 132 displaced from the position of the wrist 110 with its tip positioned within the notch 131 of the back of the hand 115, and is capable of rotating relative to the back of the hand 115 around the first ball joint 141" (see Abstract). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-28002 Summary of the Invention [Problem to be solved by the invention]

[0004] The aforementioned Patent Document 1 describes a mechanism for the joint structure of the extremities of a doll body that can perform movements similar to those of a human. However, the aforementioned Patent Document 1 does not consider a mechanism for accurately reproducing the range of motion and immobility of human fingers, or a mechanism for reproducing the diverse expressions of human fingers. Therefore, the present invention provides a mechanism for accurately reproducing the range of motion and immobility of human fingers, and a mechanism for reproducing a variety of expressions of human fingers. [Means for solving the problem]

[0005] In order to solve the above problems, for example, the configurations described in the claims are adopted. The present application includes multiple means for solving the above-mentioned problems, and one example thereof is a device having a central member consisting of a joint portion and a middle finger metacarpal portion, the joint portion consisting of a first outer portion and a first inner portion, the first outer portion rotatably housing the first inner portion, the first outer portion having at least one guide portion, and the guide portion of the first outer portion restricting uniaxial rotation around one of three rotation axes of the first inner portion. [Effects of the Invention]

[0006] According to the present invention, it is possible to provide a mechanism for accurately reproducing the range of motion and the range of immobility of human fingers, and a mechanism for reproducing a variety of expressions of human fingers. Problems, configurations, and effects other than those described above will become apparent from the following description of the embodiments. [Brief explanation of the drawings]

[0007] [Figure 1A] FIG. 1A is an example of an external view of a hand model 1 made up of multiple movable parts. [Figure 1B] FIG. 1B is an example of an external view of a possible form of the hand model 1 of FIG. 1A. [Figure 2] FIG. 2 is an example of an external view of the central member 200. As shown in FIG. [Figure 3] FIG. 3 is an example of an explanatory diagram illustrating the relationship between the lateral portion 220 and the medial portion 300 of the CM joint 20. In FIG. [Figure 4] FIG. 4 is an example of an explanatory diagram illustrating the rotation of the inner part 300 in the first rotation direction RD1. [Figure 5] FIG. 5 is an example of an explanatory diagram illustrating the rotation of the inner part 300 in the second rotation direction RD2. [Figure 6] FIG. 6 is an example of an external view of the hand model 1 when the CM joint 20 is in the state of FIG. 5A. [Figure 7] FIG. 7 is an example of an external view of the hand model 1 when the CM joint 20 is in the state of FIG. 5C. [Figure 8] FIG. 8 is an example of an explanatory diagram illustrating the rotation of the inner part 300 in the first rotation direction RD1. [Figure 9] FIG. 9 is an example of an external view of the hand model 1 when the CM joint 20 is in the state shown in FIG. [Figure 10] FIG. 10 is an example of an explanatory diagram illustrating the relationship between the thumb metacarpal portion 115, the index finger metacarpal portion 125, and the middle finger metacarpal portion 135. [Figure 11] FIG. 11 is an example of an explanatory diagram illustrating the range of motion of the thumb metacarpal portion 115. [Figure 12] FIG. 12 is an example of an external view of the hand model 1 when the thumb metacarpal portion 115 is in the state shown in FIG. [Figure 13] FIG. 13 is an explanatory diagram illustrating an example of an extension mechanism for extending the rotation range of the thumb metacarpal portion 115. [Figure 14] FIG. 14 is an example of an external view of the hand model 1 when the thumb metacarpal portion 115 is in the state shown in FIG. [Figure 15] FIG. 15 is an example of an explanatory diagram illustrating two different postures of the thumb metacarpal portion 115. [Figure 16] FIG. 16 is an example of an external view of the hand model 1 when the thumb metacarpal portion 115 is in the posture shown in FIG. 15B and FIG. 15D. [Figure 17A] FIG. 17A is an example of an external view of hand model 1 for explaining the range of motion of thumb metacarpal portion 115 corresponding to the posture of FIG. 15A. [Figure 17B] FIG. 17B is an example of an external view of hand model 1 illustrating the range of motion of thumb metacarpal portion 115 corresponding to the posture of FIG. 15B. [Figure 18] FIG. 18 is an example of an explanatory diagram illustrating the connection state of the metacarpal portion 10 of each finger portion 30. [Figure 19] FIG. 19 is an example of an explanatory diagram illustrating the metacarpal portion 10 in a flatter state. [Figure 20] FIG. 20 is an example of an explanatory diagram illustrating the metacarpal portion 10 in a more curled state. [Figure 21] FIG. 21 is an explanatory diagram illustrating an example of the configuration of the finger portion 30. [Figure 22] FIG. 22 is an example of an explanatory diagram illustrating the middle finger area 2120 of FIG. [Figure 23] FIG. 23 is an example of an explanatory diagram illustrating the MP joint portion 40. [Figure 24] FIG. 24 is an example of an explanatory diagram illustrating the rotation of the MP joint portion 40. [Figure 25] FIG. 25 is an example of an external view of the hand model 1 for explaining flexion and ulnar flexion of the middle finger 130. [Figure 26] FIG. 26 is an example of an explanatory diagram illustrating the rotation of the MP joint portion 40. [Figure 27] FIG. 27 shows examples of external views of the hand model 1 in which the rotation amount of the MP joint portion 40 is different. [Figure 28] FIG. 28 is an example of an explanatory diagram illustrating the configuration of the IP joint portion 50. [Figure 29] FIG. 29 is an example of an explanatory diagram illustrating dorsiflexion and palmar flexion of the DIP joint portion 52. [Figure 30] FIG. 30 is an example of an external view of the hand model 1 for explaining the range of motion of the MP joint portion 40 and the IP joint portion 50. [Figure 31] FIG. 31 is another example of an external view of the hand model 1 for explaining an example of the range of motion of the MP joint portion 40 and the IP joint portion 50. [Figure 32] FIG. 32 is an example of an explanatory diagram illustrating the CM joint portion 20 in a divided state. [Figure 33] FIG. 33 is another example of an explanatory diagram illustrating the connection state of the metacarpal portion 10 of each finger portion 30. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, examples will be described with reference to the drawings. In the following examples, a right hand will be used as an example, but the examples can also be applied to a left hand by reversing the left and right sides. For example, by configuring the components described below in a left-right reversed configuration, the examples described below can be applied to a left-hand hand model. Even in this case, the structure of each joint described below may be common to both the right-hand hand model and the left-hand hand model. The hand model 1 shown in Fig. 1 and other figures is designed to have an appearance that imitates an adult's hand. In another embodiment, the hand model 1 may be designed to have an appearance that imitates the appearance of an infant's or elderly's hand, for example, in terms of the proportions and external shape of each part. The external shape of each part can be designed taking into consideration shapes and contours that reproduce, for example, the degree of fleshiness and protruding bones.

[0009] FIG. 1A is an example of an external view of a hand model 1 made up of multiple movable parts. The hand model 1 in FIG. 1A is modeled after a human hand, and includes, for example, metacarpal joints 10, CM joints (carpometacarpal joints) 20, finger joints 30, MP joints (metacarpophalangeal joints) 40, and IP joints (interphalangeal joints) 50. The CM joint 20 is an example of a joint. The MP joint 40 is an example of a second joint.

[0010] The hand model 1 in FIG. 1A is designed to be similar in size to the hand of a typical adult, but it can be designed to be of various sizes, such as a size similar to the hand of an infant or young child. In particular, in a configuration in which the hand model 1 is used as a prosthetic hand, the size of the hand model 1 should be based on the hand size of the wearer of the prosthetic hand, or the average hand size for the individual body type of the wearer of the prosthetic hand.

[0011] 1A to 33 are also designed to have ratios of size and length corresponding to the parts of the fingers of a typical adult. However, in another embodiment, it is also possible to design the hand model 1 to have ratios corresponding to the size and length of the parts of the fingers of an animal other than humans, particularly a mammalian primate, such as a chimpanzee or orangutan. In a hand model 1 configured in this way, it is better to design the range of motion and immobility of the hand model 1 to correspond to the range of motion and immobility of the fingers of each animal.

[0012] For example, if the hand model 1 is designed to be smaller than the size of an average adult's hand, making it easier to carry, the hand model 1 can be easily carried to various places, making it easier for the user to practice sketching using the hand model 1 in various situations, for example, regardless of location or time of day. In another example, if the hand model 1 is designed to be larger than the size of an average adult's hand so that it can be easily seen from a long distance, even a person who is far away from the hand model 1 in a classroom or the like (for example, a student taking an art or drawing class or lecture) can easily see the hand model 1 and practice sketching using the hand model 1. For example, in an art school or the like, where multiple students are sketching the same hand model 1, it is preferable to use such a large hand model 1.

[0013] The hand model 1 can accurately reproduce the range of motion and immobility of human fingers. For example, the range of motion and immobility of the hand model 1 may be designed to reproduce the range of motion and immobility of human fingers in a normal state. However, the range of motion and immobility of the hand model 1 do not necessarily have to reproduce the range of motion and immobility of human fingers in a normal state. For example, in another embodiment, the hand model 1 may be configured to reproduce the range of motion and the range of immobility of a human hand in a state where at least one joint is dislocated or subluxated. Furthermore, the range of motion and immobility of the hand model 1 may be set around the angle at which pain begins to be felt for at least one joint in the fingers of a patient suffering from inflammation or arthropathy, such as osteoarthritis, etc. In such a configuration, it is preferable that the angle at which pain begins to be felt can be selected based on, for example, statistical data on the target arthropathy, or can be changed on a case-by-case basis.

[0014] For example, in lectures, practical training, and training sessions at hospitals, universities, and vocational schools related to medicine, nursing, welfare, etc., students and trainees can use hand model 1, which reproduces the range of motion and immobility of the hand of an injured or disabled patient, to actually touch a three-dimensional object and learn about the range of motion and immobility of a human hand with, for example, a dislocation or subluxation. Furthermore, it is possible to assign different ranges of motion and non-motion settings to each joint of each individual hand model 1 depending on the injury or disability, and to reproduce one or a combination of multiple injuries or disabilities, so that examples of various injury and disability conditions can be efficiently presented to students and trainees. Furthermore, the hand model 1 can also reproduce the condition of the fingers of an animal with an injury or disability. The hand model 1 configured in this way can provide, for example, veterinarians with an opportunity to learn about the conditions of injuries and disabilities in animals that they rarely encounter.

[0015] In this specification, the five metacarpal parts, namely, the thumb part 110, the index finger part 120, the middle finger part 130, the ring finger part 140, and the little finger part 150, which will be described later, may be collectively referred to as the individual finger metacarpal parts 10. Similarly, the thumb part 110, the index finger part 120, the middle finger part 130, the ring finger part 140, and the little finger part 150 of the hand model 1 may be referred to as the thumb, the index finger, the middle finger, the ring finger, and the little finger.

[0016] FIG. 1B is an example of an external view of a possible form of the hand model 1 of FIG. 1A. FIG. 1B(1) is a diagram of the hand model 1 with the fingers 30 separated, viewed from the back of the hand. FIG. 1B(2) is a diagram of the hand model 1 with the fingers 30 separated, viewed from the palm side. FIG. 1B(3) is a diagram of the hand model 1 with the fingers 30 brought close to each other, as viewed from the back of the hand. FIG. 1B(4) is a diagram of the hand model 1 with the fingers 30 brought close to each other, viewed from the palm side.

[0017] In the hand model 1 of the embodiment shown in Figures 1A and 1B, each of the finger sections 30, i.e., the index finger section 120, the middle finger section 130, the ring finger section 140, and the little finger section 150, consists of a proximal section 31, a middle section 32, and a distal section 33, and the thumb section 110 consists of the proximal section 31 and the distal section 33.

[0018] The metacarpal portion 10 and the proximal joints 31 of each finger portion 30 are connected to each other via MP joints 40 . The proximal interphalangeal joint 31 and the middle interphalangeal joint 32 are connected to each other via the PIP joint (proximal interphalangeal joint) 51, and the middle interphalangeal joint 32 and the distal interphalangeal joint 33 are connected to each other via the DIP joint (distal interphalangeal joint) 52. In this specification, "proximal" means a position closer to the virtual arm or body connected to the arm end 60 or hand model 1, and "distal" means a position farther from the virtual arm or body connected to the arm end 60 or hand model 1.

[0019] An arm end 60 is connected to the CM joint 20 . More specifically, the arm end 60 is fixedly connected to the medial part 300 of the CM joint 20, and the arm end 60 supports the medial part 300 of the CM joint 20 so that it can rotate relative to the lateral part 220 of the CM joint 20. The term "rotation" may be read as "turn."

[0020] The CM joint 20 is made up of an inner part 300 that is fixedly connected to the arm end 60, and an outer part 220 that houses the inner part 300 in a rotatable manner. The lateral portion 220 of the CM joint 20 is formed integrally with or fixed to the middle finger metacarpal portion 135, as will be described in detail below with reference to FIGS.

[0021] The thumb metacarpal portion 115, index finger metacarpal portion 125, ring finger metacarpal portion 145, and little finger metacarpal portion 155 are directly or indirectly connected to the lateral portion 220 of the CM joint portion 20 in a manner that allows them to move relative to the middle finger metacarpal portion 135. In such a configuration, it is particularly preferable that the thumb metacarpal portion 115, index finger metacarpal portion 125, ring finger metacarpal portion 145, and little finger metacarpal portion 155 be movable relative to the lateral portion 220 of the CM joint portion 20.

[0022] The thumb portion 110, which corresponds to the human thumb, is composed of a proximal joint portion 31 and a distal joint portion 33, an MP joint portion 40 that rotatably connects the proximal joint portion 31 to the thumb metacarpal portion 115, and an IP joint portion 50 that rotatably connects the proximal joint portion 31 and the distal joint portion 33.

[0023] The proximal joint 31, middle joint 32, and distal joint 33 of each finger 30, the MP joint 40, and the IP joint 50 have similar configurations, and in the following explanation, the explanation regarding the proximal joint 31, middle joint 32, and distal joint 33 of the middle finger 130 corresponding to a person's middle finger, the MP joint 40, and the IP joint 50 can also be applied to the index finger 120, the ring finger 140, and the little finger 150 in the same manner.

[0024] Each finger portion 30 corresponding to the four fingers of a human, i.e., the index finger, middle finger, ring finger, and little finger, is composed of a proximal joint portion 31, a middle joint portion 32, a distal joint portion 33, an MP joint portion 40 that rotatably connects the proximal joint portion 31 to the metacarpal portion 10, a PIP joint portion 51 that rotatably connects the proximal joint portion 31 to the middle joint portion 32, and a DIP joint portion 52 that rotatably connects the distal joint portion 33 to the middle joint portion 32. In the following description, the PIP joint portion 51 and the DIP joint portion 52 may be collectively referred to as the IP joint portion 50.

[0025] The PIP joint portion 51 and the DIP joint portion 52 have a similar or equivalent configuration as the IP joint portion 50 . The MP joint portion 40 and the IP joint portion 50 have different configurations with respect to the range of motion, particularly with respect to the degree of freedom of motion. These points will be explained in more detail with reference to FIGS. 22 to 29.

[0026] FIG. 2 is an example of an external view of the central member 200. As shown in FIG. In FIG. 2, the central member 200 is shown with the lateral portion 220 of the CM joint 20 and the metacarpal portion 135 of the middle finger fixedly connected, and the medial portion 300 of the CM joint 20 removed.

[0027] The lateral portion 220 of the CM joint 20 accommodates the medial portion 300 of the CM joint 20 . The lateral part 220 of the CM joint 20 further has a lateral part 221 of the thumb CM joint 1011 that constitutes a part of the thumb CM joint 1011 for the thumb, which will be specifically described using FIG. Furthermore, the lateral portion 220 of the CM joint portion 20 has a first support protrusion 226 that supports the metacarpal portion 125 of the index finger and a second support protrusion 227 that supports the metacarpal portion 145 of the ring finger.

[0028] The lateral portion 220 of the CM joint 20 is an example of a first lateral portion, and the medial portion 300 of the CM joint 20 is an example of a first medial portion. The thumb CM joint 1011 for the thumb is an example of a thumb joint. The lateral portion 221 of the thumb CM joint 1011 is an example of the second lateral portion.

[0029] 18 , the index finger metacarpal portion 125 may have a first support protrusion insertion hole 1810, and the ring finger metacarpal portion 145 may have a second support protrusion insertion hole 1820. In such a configuration, by inserting the first support protrusion 226 into the first support protrusion insertion hole 1810 and inserting the second support protrusion 227 into the second support protrusion insertion hole 1820, the index finger metacarpal portion 125 and the ring finger metacarpal portion 145 can be held on the lateral portion 220 of the CM joint 20 while maintaining a state in which they can rotate relative to the lateral portion 220 of the CM joint 20.

[0030] The lateral portion 220 of the CM joint portion 20 has a first linear guide edge 222 and a second linear guide edge 223 , and a first curved guide edge 224 and a second curved guide edge 225 . The first linear guide edge 222 and the second linear guide edge 223 form a first guide portion 400 . The first curved guide edge 224 and the second curved guide edge 225 form a second guide portion 500 .

[0031] The central axis 230 indicated by the dashed line between L-L' is a straight line extending in the longitudinal direction of the central member 200, and is, for example, a straight line passing through the center of the partial spherical shell formed by the outer part 220 of the CM joint part 20 or the center of the spherical part of the inner part 300 of the CM joint part 20, and extending parallel to the plane in which the first curved guide edge 224 and the second curved guide edge 225 exist.

[0032] FIG. 3 is an example of an explanatory diagram illustrating the relationship between the lateral portion 220 and the medial portion 300 of the CM joint 20. In FIG. FIG. 3(A) illustrates the CM joint portion 20 with the lateral portion 220 and the medial portion 300 separated. 3(B) illustrates the CM joint unit 20 in a state in which the inner unit 300 is housed in the outer unit 220. Note that in actual use, the CM joint unit 20 may be configured so that the outer unit 220 and the inner unit 300 cannot be separated without damage or deformation, as shown in FIG. 3(A). However, the outer unit 220 may be configured from multiple members, and the multiple members may be fitted together to sandwich the inner unit 300, making assembly easier, or the CM joint unit 20 may be configured so that they can be separated after assembly.

[0033] The double-headed arrows labeled RD1 and RD2 in Figure 3(B) indicate the first possible rotation direction (first allowable rotation direction) RD1 and the second possible rotation direction (second allowable rotation direction) RD2 of the inner part 300 when housed in the outer part 220. When housed in the outer part 220, the inner part 300 may be configured to restrict rotation in at least a portion of the range in the third rotation direction (restricted rotation direction) RD3 indicated by the double arrow in Figure 4(A). Note that "restricting" includes preventing rotation, but a certain degree of play (rotation) is permitted.

[0034] This allows the outer part 220 to accommodate the inner part 300 while restricting the rotational movement of the inner part 300 in three degrees of freedom. The rotational movement with three degrees of freedom is, for example, a rotational movement consisting of pitch rotation, yaw rotation, and roll rotation about the central axis 230. In the embodiment of Fig. 3(B), the rotational movement with three degrees of freedom of the inner part 300 can be limited by limiting the roll rotation about the central axis 230. For example, it is possible to configure the inner part 300 so that roll rotation is not possible, or to make roll rotation more difficult than pitch rotation or yaw rotation.

[0035] Note that the pitch rotation, yaw rotation, and roll rotation relative to the central axis 230 are examples of rotation of the inner part 300 around three rotation axes, and the roll rotation is an example of a single-axis rotation around one of the three rotation axes.

[0036] The middle finger metacarpal portion 135 has an inner wall portion 340 of the middle finger metacarpal portion 135 between the palmar surface 360 of the middle finger metacarpal portion 135 and the back surface 210 of the middle finger metacarpal portion 135. The inner wall portion 340 forms a thumb metacarpal receiving portion 350 and a thenar receiving portion 1520 (described later) on the thumb metacarpal portion 115 side.

[0037] FIG. 32 is an example of an explanatory diagram illustrating the CM joint portion 20 in a divided state. The CM joint portion 20 may have the configuration shown in Fig. 32 instead of the configuration shown in Fig. 3 to Fig. 5, for example. The lateral portion 220 of the CM joint portion 20 having the configuration shown in Fig. 32 is formed by combining a first half 3210 and a second half 3220.

[0038] The first half 3210 is provided with the outer portion 221 of the thumb CM joint 1011 and the first tubular member 3211. The second half 3220 is provided with the second tubular member 3221 and a connection portion 3222 with the middle finger metacarpal portion 135. A screw can be inserted into the first tubular member 3211, and the distance from the second tubular member 3221 can be adjusted by tightening or loosening the screw, thereby adjusting the frictional force generated between the first tubular member 3211 and the inner portion 300. Similarly, the outer portion 221 may be configured by combining two halves, such as the first half 3210 and the second half 3220, and each of the two halves may be provided with a screw hole for inserting a screw, so that the frictional force with the inner portion 300 can be adjusted by inserting the screw. A connection portion similar to the connection portion 3222 with the middle finger metacarpal portion 135 is also provided on the first half 3210, and these are paired and connect with corresponding connection portions on the middle finger metacarpal portion 135 side, maintaining a fixed connection between the middle finger metacarpal portion 135 and the CM joint portion 20. The specific configurations and functions of the individual components of the CM joint 20 will be described later.

[0039] For example, in a hand model 1 having a CM joint 20 configured according to Figures 3 to 5 or 32, the ease of movement and ease of maintaining posture of the CM joint 20 and components distal to the CM joint 20 relative to the arm end 60 can be adjusted based on the frictional force generated between the outer part 220 of the CM joint 20 and the inner part 300 of the CM joint 20. For example, in a hand model 1 used as a drawing model, a configuration in which a relatively large frictional force is generated between the outer part 220 of the CM joint 20 and the inner part 300 of the CM joint 20 can be configured to make it more difficult for the CM joint 20 and components distal to the CM joint 20 to move relative to the arm end 60. This more reliably prevents the hand model 1 from being deformed into an undesired position relative to the arm end 60 due to vibrations, collisions, changes in acceleration, etc., during transportation or storage of the hand model 1 after setting up.

[0040] For example, in a hand model 1 used as a prosthetic hand, a relatively small frictional force is generated between the outer portion 220 of the CM joint 20 and the inner portion 300 of the CM joint 20, thereby making it possible to more easily change the state of the CM joint 20 relative to the arm end 60 in accordance with the movements of the user in their daily life. As a result, the state of the CM joint 20 relative to the arm end 60 changes in accordance with the daily movements of a user wearing a prosthetic hand equipped with the hand model 1, particularly the movements of the arm wearing the prosthetic hand, for example, based on changes in the direction, speed, and acceleration of the movement, making it possible to reproduce natural movements similar to those of an actual human hand within a natural range of motion.

[0041] Based on the above-mentioned frictional forces and the settings of the range of motion and non-range of motion of the hand model 1, the hand model 1 can accurately reproduce the movements of an actual human hand, such as shaking, during the user's movements, even without an electrical control unit or drive unit. Furthermore, the hand model 1 is preferably configured to be able to adjust the frictional force of each joint, for example, the frictional force generated between the outer part 220 of the CM joint 20 and the inner part 300 of the CM joint 20. Such a configuration will be described later with reference to FIG.

[0042] FIG. 4 is an example of an explanatory diagram illustrating the rotation of the inner part 300 in the first rotation direction RD1. FIG. 4(A) illustrates the CM joint 20 with the lateral portion 220 of the CM joint 20 and the medial portion 300 of the CM joint 20 separated. FIG. 4(B) illustrates the CM joint 20 in a state in which the medial portion 300 of the CM joint 20 is housed in the lateral portion 220 of the CM joint 20.

[0043] 4(A), the first guide portion 400 is indicated by a dashed line. The first guide portion 400 is a space sandwiched between the first linear guide edge 222 and the second linear guide edge 223 of the outer portion 220, and has a width that allows the first guide protrusion 310 and the second guide protrusion 320 to pass through. The first guide portion 400 is an example of the at least one guide portion.

[0044] 4(A) also shows a central axis 230 that passes through the center of the partial spherical shell formed by the outer portion 220. The third rotation direction RD3 that is restricted is the direction of rotation around this central axis 230.

[0045] 4(A), the inner part 300 has a first guide protrusion 310, a second guide protrusion 320, and a connecting protrusion 330. The connecting protrusion 330 is a connecting part for connecting the inner part 300 to the arm end part 60, and the connecting protrusion 330 is provided with a hook part 410, which prevents the arm end part 60 connected to the inner part 300 via the connecting protrusion 330 from spinning freely.

[0046] 4(A), the first guide portion 400 is formed as a linear cavity that is continuously connected between the palm side and the back side of the hand. Alternatively, the first guide portion 400 may be formed as a cavity that is divided into two: a first cavity on the palm side and a second cavity on the back side of the hand.

[0047] 4(B), a portion of the first guide portion 400 is indicated by a dashed line. In FIG. 4B, the first guide protrusion 310 is located outside the range of the first guide portion 400, and the second guide protrusion 320 is located within the range of the first guide portion 400.

[0048] In the state shown in Figure 4(B), the first guide portion 400 represented by the dashed line is a space sandwiched between the first linear guide edge 222 and the second linear guide edge 223 of the outer portion 220, and its width is long enough to allow the first guide protrusion 310 and the second guide protrusion 320 to pass through.

[0049] 4(B), the second guide protrusion 320 in the first guide part 400 is restricted from moving in the width direction of the first guide part 400 by the first linear guide edge 222 and the second linear guide edge 223. This prevents the inner part 300 from rotating around the central axis 230 in the third rotation direction RD3.

[0050] In particular, in a configuration in which the width of the first guide portion 400 matches the width of the first guide protrusion 310 and the second guide protrusion 320, for example, in a configuration in which the first guide protrusion 310 and the second guide protrusion 320 contact the first linear guide edge 222 and the second linear guide edge 223 within the first guide portion 400, rotation in the third rotation direction RD3 around the central axis 230 of the inner portion 300 can be more reliably restricted.

[0051] The hand model 1 according to this embodiment can effectively reproduce the state in which the fingers beyond the wrist are restricted from rotating relative to the wrist when the human hand or arm undergoes radial abduction and palmar abduction.

[0052] The third rotation direction RD3 may be understood as a rotation direction defined by a roll angle relative to the central axis 230. Similarly, the first rotation direction RD1 and the second rotation direction RD2 may be understood as directions of rotation defined by the yaw angle and pitch angle relative to the central axis 230, respectively.

[0053] In the following description, rotation defined by the yaw angle will be described using the terms flexion and ulnar flexion, and rotation defined by the pitch angle will be described using the terms volar flexion and dorsiflexion. Furthermore, with regard to the MP joint 40 and IP joint 50 of each finger 30, the rotation defined by the yaw angle and the rotation defined by the pitch angle with respect to the longitudinal axis of the proximal phalanx 31, the middle phalanx 32, and the distal phalanx 33 of each finger 30 will be similarly described using the terms flexion and ulnar flexion, and the terms palmar flexion and dorsiflexion, respectively.

[0054] FIG. 5 is an example of an explanatory diagram illustrating the rotation of the inner part 300 in the second rotation direction RD2. Fig. 5(A) shows a state in which inner part 300 has rotated from the central position of inner part 300 shown in Fig. 5(B) toward the palm side, as viewed from the back of the hand toward the palm side, and as viewed in a direction parallel to central axis 230. In Fig. 5(A), first guide protrusion 310 of inner part 300 is located within first guide part 400 on the palm side, and second guide protrusion 320 and connecting protrusion 330 are located within second guide part 500. The central position of the inner part 300 is, for example, the position where the connecting protrusion 330 of the inner part 300 overlaps with the central axis 230.

[0055] 5(B) shows the state in which the inner part 300 is in the central position of the inner part 300, viewed from the back of the hand toward the palm, and viewed in a direction parallel to the central axis 230. At the central position of the inner part 300, the connecting protrusion 330 of the inner part 300 may overlap with the central axis 230 of the central member 200, for example. In FIG. 5(B), the first guide protrusion 310 of the inner part 300 is located on the palm side, and the second guide protrusion 320 is located on the back side, both within the first guide part 400, and the connecting protrusion 330 is located within the second guide part 500.

[0056] 5(C) shows a state in which the inner part 300 has been rotated from the central position of the inner part 300 shown in FIG. 5(B) toward the back of the hand, as viewed from the direction from the back of the hand toward the palm, and as viewed in a direction parallel to the central axis 230. In FIG. 5(C), the second guide protrusion 320 of the inner part 300 is located within the first guide part 400 on the back of the hand, and the first guide protrusion 310 and the connecting protrusion 330 are located within the second guide part 500. Although detailed description will be omitted, when the inner part 300 is rotated along the second rotation direction RD2 as shown in FIG. 5(A) and FIG. 5(C), further movement is restricted by contact between the edge of the arm end 60 on the CM joint part 20 side and the outer part 220 at the limit position, in order to achieve a range of movement similar to that of a human wrist joint.

[0057] FIG. 6 is an example of an external view of the hand model 1 when the CM joint 20 is in the state of FIG. 5(A). FIG. 6(A) is an example of an external view of the hand model 1 seen from above when the CM joint portion 20 is in the state of FIG. 5(A). FIG. 6(B) is an example of an external view of the hand model 1 seen from the side when the CM joint portion 20 is in the state of FIG. 5(A).

[0058] In the hand model 1 in the state shown in Figures 6(A) and 6(B), as explained in relation to Figure 5(A), the first guide protrusion 310 of the inner part 300 is located within the first guide part 400, so that it is possible to more reliably restrict the arm end part 60, which is fixedly connected to the inner part 300 via the connecting protrusion 330, from rotating in the third rotation direction RD3 within the outer part 220.

[0059] Rotation of the fingers relative to the wrist, such as the rotation of the inner part 300 in the third rotation direction RD3 that is restricted within the outer part 220, is similarly restricted in the anatomical structure of a human arm and hand, which has a structure different from that of this embodiment. This allows the hand model 1 to accurately reproduce both the range of motion and the range of immobility of an actual human arm and hand.

[0060] FIG. 7 is an example of an external view of the hand model 1 when the CM joint 20 is in the state of FIG. 5(A). FIG. 7(A) is an example of an external view of the hand model 1 seen from above when the CM joint portion 20 is in the state of FIG. 5(A).

[0061] FIG. 7(B) is an example of an external view of the hand model 1 seen from the side when the CM joint portion 20 is in the state of FIG. 5(A). FIG. 7C is an example of an enlarged view of the area 700 enclosed by the dashed line in FIG. 7A.

[0062] In the hand model 1 in the states shown in Figures 7(A) to 7(C), as explained in relation to Figure 5(A), the second guide protrusion 320 of the inner part 300 is located within the first guide part 400, so that it is possible to more reliably restrict the arm end part 60, which is fixedly connected to the inner part 300 via the connecting protrusion 330, from rotating in the third rotation direction (restricted rotation direction) RD3 within the outer part 220.

[0063] As in the case of Figure 6, the rotation of the inner part 300 in the third rotation direction RD3, which is restricted within the outer part 220, is also restricted by the anatomical structure of the human arm and hand, which has a different structure from that of this embodiment. As in the case of FIG. 6, in the case of FIG. 7, the hand model 1 can accurately reproduce both the range of motion and the range of immobility of an actual human arm or hand.

[0064] The arm end 60 may have a fixing member insertion hole 710 at its proximal end. It is preferable that a fixing member provided on an object separate from the hand model 1 can be inserted into the fixing member insertion hole 710. The object separate from the hand model 1 may be, for example, a base for placing the hand model 1 on a desk or shelf, a forearm member for integrating with the hand model 1 to form a larger body model, or a connection part for connecting to the hand part of a forearm prosthesis or upper arm prosthesis. Note that the arm end 60 may be configured to be fixed using four small holes (the number of holes may be other numbers) provided around the fixing member insertion hole 710 shown in FIG. 7.

[0065] The user can move the hand model 1 while holding the fixing member inserted in the fixing member insertion hole 710, or a base or forearm member having the fixing member, thereby moving the hand model 1 as a whole while more stably maintaining the state of the hand model 1 once it has been set. This allows the user to observe the hand model 1 in the same state from various angles, such as up and down, left and right, front and back, and stably practice sketching, for example.

[0066] Furthermore, when hand model 1 is used as a prosthetic hand, it becomes easier to pose like a family member or friend, down to the fine details of the fingers, for example, when taking a photograph, which can also contribute to improving the quality of life (QOL) of the wearer of the prosthetic hand. When hand model 1 is used as a prosthetic hand, it is even better if it can be replaced with a hand part having a different function or configuration, such as a hook-shaped hand part, by releasing the connection at fixing member insertion hole 710, because this allows for different uses depending on the situation in daily life.

[0067] The arm end portion 60 may have a recess 720 that corresponds to, for example, closely overlaps with, the contour shape, particularly the three-dimensional contour shape, of the outer portion 221 of the thumb CM joint 1011. This allows for more flexible design of the range of motion of the CM joint 20.

[0068] FIG. 8 is an example of an explanatory diagram illustrating the rotation of the inner part 300 in the first rotation direction RD1. Fig. 8(A) shows the state in which the inner part 300 has been rotated toward the little finger from the central position of the inner part 300 shown in Fig. 8(B). In Fig. 8(A), the first guide protrusion 310 and the second guide protrusion 320 of the inner part 300 are positioned within the first guide part 400. The connecting protrusion 330 is positioned within the second guide part 500 and is in contact with the first curved guide edge 224.

[0069] 8(B) shows a state in which the inner part 300 is in the central position of the inner part 300. At the central position of the inner part 300, the connecting protrusion 330 of the inner part 300 may overlap with the central axis 230 of the central member 200, for example.

[0070] The first curved guide edge 224 and the second curved guide edge 225 may be designed asymmetrically with respect to the center line L2-L2′ passing through the centers of the first guide protrusion 310 and the second guide protrusion 320 of the inner part 300. In particular, it is better if the first distance 820 between the thumb side end point 810 of the first curved guide edge 224 and the center line L2-L2' is designed to be shorter than the second distance 840 between the little finger side end point 830 of the second curved guide edge 225 and the center line L2-L2', as this can imitate the range of motion and non-motion of an actual human wrist with a higher degree of fidelity. It should be noted that the first distance 820 and the second distance 840 are distances when viewed in a direction parallel to the central axis 230.

[0071] Figure 8(C) shows a state in which the inner part 300 has been rotated toward the thumb from the central position of the inner part 300 shown in Figure 8(B). In Figure 8(C), similar to Figure 8(A), the first guide protrusion 310 and the second guide protrusion 320 of the inner part 300 are positioned within the first guide part 400. The connecting protrusion 330 is positioned within the second guide part 500 and is in contact with the second curved guide edge 225.

[0072] FIG. 9 is an example of an external view of the hand model 1 when the CM joint 20 is in the state shown in FIG. FIG. 9(A) is an example of an external view of the hand model 1 seen from the back of the hand when the CM joint portion 20 is in the state of FIG. 8(A). FIG. 9(B) is an example of an external view of the hand model 1 seen from the back of the hand when the CM joint 20 is in the state of FIG. 8(C).

[0073] 9(A), when the arm end portion 60 is moved while the connecting protrusion 330 remains in contact with the first curved guide edge, at least one of the first guide protrusion 310 and the second guide protrusion 320 moves within the first guide section 400. When the arm end portion 60 is moved so that the connecting protrusion 330 moves away from the first curved guide edge 224 and then comes into contact with the second curved guide edge 225, at least one of the first guide protrusion 310 and the second guide protrusion 320 moves within the first guide section 400, and the hand model 1 transitions to the state shown in FIG.

[0074] FIG. 10 is an example of an explanatory diagram illustrating the relationship between the thumb metacarpal portion 115, the index finger metacarpal portion 125, and the middle finger metacarpal portion 135. FIG. 10(A) is an example of an explanatory diagram illustrating a state in which the metacarpal portions 10 (115, 125, 135) of the thumb, index finger, and middle finger are connected.

[0075] FIG. 10(B) is an example of an explanatory diagram illustrating the state in which the metacarpal portions 10 (115, 125, 135) of the thumb, index finger, and middle finger are disassembled. The central member 200 is connected to the index finger metacarpal portion 125 via a hinge connection portion (butterfly plate-shaped connection portion) 1000 provided on the middle finger metacarpal portion 135. The middle finger metacarpal portion 135 and the index finger metacarpal portion 125 can rotate slightly relative to each other around the hinge connection portion 1000.

[0076] The central member 200 is connected to the thumb metacarpal portion 115 via the thumb CM joint portion 1011 of the CM joint portion 20. The thumb CM joint 1011 is composed of an inner part 1020 of the thumb CM joint 1011 and an outer part 221 of the thumb CM joint 1011. The thumb CM joint 1011 is preferably configured so that the thumb metacarpal part 115 can rotate with respect to the middle finger metacarpal part 135 with one to three degrees of freedom. The medial portion 1020 of the thumb CM joint 1011 is an example of a second medial portion.

[0077] The rotation of the thumb metacarpal portion 115 will be specifically described below with reference to FIGS. FIG. 11 is an example of an explanatory diagram illustrating the range of motion of the thumb metacarpal portion 115. 11(A) illustrates a state in which the thumb CM joint 1011 has moved to the first outer position. At the first outer position of the thumb CM joint 1011, the contact protrusion 1100 of the thumb metacarpal portion 115 contacts the outermost contact position 1121 of the stopper wall portion 1120 of the index finger metacarpal portion 125.

[0078] When the thumb metacarpal portion 115 rotates in the direction from the back of the hand toward the palm, the contact protrusion 1100 comes into contact with the stopper wall 1120 of the index finger metacarpal portion 125. As a result, the stopper wall 1120 of the index finger metacarpal portion 125 restricts the thumb metacarpal portion 115 from rotating beyond the palm surface toward the palm side (palmar flexion).

[0079] 11(B) illustrates a state in which the thumb CM joint 1011 has moved to the medial position. At the medial position of the thumb CM joint 1011, the contact protrusion 1100 of the thumb metacarpal portion 115 may be in contact with, for example, the inner wall portion 340 of the middle finger metacarpal portion 135.

[0080] The thumb CM joint 1011 may provide multiple trajectories of movement for the thumb metacarpal portion 115 while moving from the first outer position to the inner position. For example, the thumb metacarpal portion 115 may be able to rotate differently around the thumb CM joint 1011 or may be able to assume different states with respect to tilt, orientation, or posture when moving from the first outer position to the inner position.

[0081] FIG. 12 is an example of an external view of the hand model 1 when the thumb metacarpal portion 115 is in the state shown in FIG. FIG. 12(A) is an example of an external view of the hand model 1 seen from the palm side when the thumb CM joint 1011 is in the state of FIG. 11(A).

[0082] FIG. 12(B) is an example of an external view of the hand model 1 seen from the palm side when the thumb CM joint 1011 is in the state of FIG. 11(B). The thumb metacarpal portion 115 can move smoothly within the area of the index finger metacarpal portion 125 while moving from the state of FIG. 12(A) to the state of FIG. 12(B). In either state, the MP joint 40 and IP joint 50 of the thumb 110 can rotate smoothly.

[0083] Similarly, in either state, the MP joint 40 and IP joint 50 of the index finger 120 to the little finger 150 can also rotate smoothly. The state of the thumb CM joint 1011 does not hinder the rotation of each MP joint 40 and IP joint 50 of each finger 30, and therefore the hand model 1 according to this embodiment can reproduce the shape of human fingers very well.

[0084] FIG. 13 is an explanatory diagram illustrating an example of an extension mechanism for extending the rotation range of the thumb metacarpal portion 115. Figure 13(A) illustrates the thumb metacarpal portion 115 in a state in which the main body of the thumb metacarpal portion 115 is separated from the expansion portion 1300. Figure 13(A) also illustrates the expansion portion 1300 in a retracted state and the expansion portion 1300 in an expanded state. The expansion section 1300 has a rotating convex portion 1321. In the assembled state shown in Fig. 13(B), the rotating convex portion 1321 is housed in a rotating concave portion 1320 of the main body of the thumb metacarpal portion 115. This allows the expansion section 1300 to rotate continuously between the housed state and the expanded state.

[0085] FIG. 13(B) illustrates the thumb metacarpal portion 115 with the extension portion 1300 retracted. FIG. 13(C) illustrates the thumb metacarpal portion 115 with the extension portion 1300 in an extended position.

[0086] FIG. 14 is an example of an external view of the hand model 1 when the thumb metacarpal portion 115 is in the state shown in FIG. FIG. 14(A) is an example of an external view of the hand model 1 seen from the palm side when the thumb metacarpal portion 115 is in the state of FIG. 13(B). FIG. 14(B) is an example of an external view of the hand model 1 seen from the palm side when the thumb metacarpal portion 115 is in the state of FIG. 13(C).

[0087] 14(A) to the state of FIG. 14(B), the contact protrusion 1100 of the thumb metacarpal portion 115 remains in contact with, for example, the outermost contact position 1121 of the stopper wall portion 1120 of the index finger, and the extension portion 1300 continues to rotate around the rotation portion 1330, allowing the thumb metacarpal portion 115 to move further outward. Note that, when the state of FIG. 14(B) is reached, the movement of the extension protrusion 1301 is restricted by the stopper recess 1311, thereby restricting further movement of the extension portion 1300.

[0088] Although not shown, a pin that fits into a stopper recess 1311 and rotates in the depth and front directions of Fig. 13(A) is provided at the opposite end of the arc surface of the extension protrusion 1301, and the stopper recess 1311 is an arc-shaped groove that guides the pin along the arc. This allows the extension portion 1300 to rotate along the arc and also limits the maximum range of movement when extended.

[0089] Even while the expansion section 1300 moves from the stored state to the expanded state, the MP joint 40 and IP joint 50 of the thumb section 110 can rotate smoothly. Similarly, in either state, the MP joint 40 and IP joint 50 of the index finger section 120 to the little finger section 150 can also rotate smoothly.

[0090] Since the state of the extension section 1300 does not hinder the rotation of each MP joint section 40 and IP joint section 50 of each finger section 30, the hand model 1 according to this embodiment can more effectively reproduce the shape expressed by human fingers.

[0091] FIG. 15 is an example of an explanatory diagram illustrating two different postures of the thumb metacarpal portion 115. FIG. 15(A) is an example of an explanatory diagram illustrating a posture in which the front side of the thumb metacarpal portion 115 faces the back side of the hand when viewed in a direction substantially parallel to the central axis 230. FIG. 15(B) is an example of an explanatory diagram illustrating a posture in which the front side of the thumb metacarpal portion 115 faces the palm side when viewed in a direction substantially parallel to the central axis 230.

[0092] 15(A) and 15(B), the direction in which the front side of the thumb metacarpal portion 115 faces is set as a direction perpendicular to the plane of the MP joint mounting recess 1500 of the thumb metacarpal portion 115. The front side of the thumb metacarpal portion 115 may be read as the back side of the thumb metacarpal portion 115. In the hand model 1, the front side (back side) of the thumb metacarpal portion 115 can face the palm side of the hand model 1, just like the fingers of a human hand.

[0093] FIG. 15(C) is an example of an external view of the thumb metacarpal portion 115 in the position of FIG. 15(A) as viewed from the palm side. FIG. 15(D) is an example of an external view of the thumb metacarpal portion 115 in the position of FIG. 15(B) as viewed from the palm side.

[0094] In the posture of FIG. 15(C), the rotating portion 1330 of the thumb metacarpal portion 115 is located closer to the central member 200 than the thenar portion 1510 of the thumb metacarpal portion 115. 15(D), the ball 1510 of the thumb metacarpal portion 115 is positioned closer to the central member 200 than the rotating portion 1330 of the thumb metacarpal portion 115. The ball 1510 can also move further toward the central member 200 from the position of FIG. 15(D) until it comes into contact with the ball receiving portion 1520 of the middle finger metacarpal portion 135. The maximum range of movement of the ball 1510 toward the central member 200 is designed to be the position where the thumb metacarpal portion 115 comes into contact with the lateral portion 220. Additionally, the ball receiving portion 1520 may be configured to be spatially connected to the receiving portion 350 for the thumb metacarpal portion 115. In such a configuration, the ball receiving portion 1520 may also function as the receiving portion 350 for the thumb metacarpal portion 115, and similarly, the receiving portion 350 for the thumb metacarpal portion 115 may also function as the ball receiving portion 1520.

[0095] Because the thumb metacarpal portion 115 can take different postures as shown in FIG. 15, the hand model 1 of this embodiment can reproduce the various shapes that a human hand can express very well.

[0096] Additionally, the hand model 1 of this embodiment may have a function to prevent the reproduction of shapes that cannot be expressed due to limitations of the anatomical structure of a human hand. This point will be explained in more detail using Figures 17A and 17B.

[0097] FIG. 16 is an example of an external view of the hand model 1 when the thumb metacarpal portion 115 is in the posture shown in FIG. 15(B) and FIG. 15(D). FIG. 16(A) is an example of an external view of the palm of the hand model 1 when the thumb metacarpal portion 115 is in the position shown in FIG. 15(B) or FIG. 15(D). FIG. 16(B) is an example of an external view of hand model 1 when viewed from the fingertip side toward the wrist side, with thumb metacarpal portion 115 in the position shown in FIG. 15(B) and FIG. 15(D).

[0098] In FIG. 16(A), most of the thumb metacarpal portion 115 overlaps the index finger metacarpal portion 125 and the middle finger metacarpal portion 135. 16(A) and 16(B), the shape of a fist can be formed by bending the thumb 110 and then bending the remaining four fingers. The fist shape of the hand model 1 obtained in this way can very well reproduce the shape of a fist made by a human hand, since the thumb metacarpal portion 115 is in the position shown in FIG. 15(B) and FIG. 15(D).

[0099] FIG. 17A is an example of an external view of hand model 1 for explaining the range of motion of thumb metacarpal portion 115 corresponding to the posture of FIG. 15(A). In FIG. 17A(1), the contact protrusion 1100 is in contact with the index finger metacarpal portion 125 at the outermost contact position 1121 of the stopper wall portion 1120, similar to FIG. 15(A). 17A(2), the contact protrusion 1100 is accommodated in the accommodation portion for the thumb metacarpal portion 115 of the middle finger metacarpal portion 135. In this case, the contact protrusion 1100 may be in contact with the accommodation portion 350 for the thumb metacarpal portion 115.

[0100] The thumb metacarpal portion 115 corresponding to the posture of Figure 15(A) can move between a state in which the contact protrusion 1100 contacts the index finger metacarpal portion 125 at the outermost contact position 1121 of the stopper wall portion 1120 as shown in Figure 17A(1) to a state in which the contact protrusion 1100 is accommodated in the accommodation portion 350 for the thumb metacarpal portion 115 as shown in Figure 17A(2), in particular, a state in which the contact protrusion 1100 contacts the accommodation portion 350 for the thumb metacarpal portion 115.

[0101] Rotation of the thumb metacarpal portion 115 around the thumb CM joint 1011, such that the thumb metacarpal portion 115 rises vertically relative to the plane of the drawing, is limited within a very narrow rotation range by the contact of the contact protrusion 1100 with the stopper wall portion 1120 in FIG. 17A(1), and similarly by the contact of the outer surface near the extension portion accommodating region 1310 with the stopper wall portion 1120 in FIG. 17A(2). The very narrow rotation range is determined, for example, by the cavity width of the index finger metacarpal portion 125. Note that the rotation range may be restricted by contact only with the middle finger metacarpal portion 135 (the wall surface of the accommodation portion 350 for the thumb metacarpal portion 115), or by contact with both the stopper wall portion 1120 and the middle finger metacarpal portion 135. The outer surface near the extension housing area 1310 may be considered as the outer surface of the thumb metacarpal portion 115 on the palm side.

[0102] As a result, in the hand model 1 of this embodiment, it is possible to more reliably restrict movement of the thumb metacarpal portion 115 beyond the range of motion expected from the actual range of motion of the thumb and thenar eminence of a human hand.

[0103] FIG. 17B is an example of an external view of hand model 1 for explaining the range of motion of thumb metacarpal portion 115 corresponding to the posture of FIG. 15(B). In FIG. 17B(1), the contact protrusion 1100 also contacts the index finger metacarpal portion 125 at the outermost contact position 1121 of the stopper wall portion 1120. In FIG. 17B(2), the upper edge 1720 of the metacarpal portion of the thumb is in contact with the contact edge 1710 of the stopper wall portion 1120.

[0104] The thumb metacarpal portion 115 corresponding to the posture of Figure 15(B) can move between a state in which the contact protrusion 1100 contacts the index finger metacarpal portion 125 at the outermost contact position 1121 of the stopper wall portion 1120 as shown in Figure 17B(1) to a state in which the upper edge 1720 of the thumb metacarpal portion contacts the contact edge 1710 of the stopper wall portion 1120 as shown in Figure 17B(2).

[0105] In FIG. 17B(2), the movement of the thumb metacarpal portion 115 is stopped when the upper edge 1720 of the thumb metacarpal portion contacts the contact edge 1710 of the stopper wall portion 1120. However, depending on the inclination of the thumb metacarpal portion 115 relative to the index finger metacarpal portion 125 and the middle finger metacarpal portion 135, the thumb metacarpal portion 115 can also move until the thenar eminence portion 1510 of the thumb metacarpal portion 115 is received in the thenar eminence receiving portion 1520 of the middle finger metacarpal portion 135, in particular until it comes into contact with the thenar eminence receiving portion 1520.

[0106] Even in this case, the upper edge 1720 of the thumb metacarpal portion can remain in contact with the contact edge 1710 of the stopper wall portion 1120. Depending on the design of the upper edge 1720 of the thumb metacarpal portion and the contact edge 1710 of the stopper wall portion 1120, the thumb metacarpal portion 115 may be configured such that the upper edge 1720 of the thumb metacarpal portion is separated from the contact edge 1710 of the stopper wall portion 1120 when the ball portion 1510 of the thumb metacarpal portion 115 is received in the ball portion receiving portion 1520 of the middle finger metacarpal portion 135.

[0107] When the thumb metacarpal portion 115 is in the position shown in Figure 15(B), rotation of the thumb metacarpal portion 115 around the thumb CM joint 1011, such as rotating upright perpendicular to the plane of the drawing, is restricted in both Figures 17B(1) and 17B(2) by the contact protrusion portion 1100 contacting the stopper wall portion 1120 with the extension portion 1300 exposed from the extension portion accommodating area 1310.

[0108] 17A(1) and 17A(2), that is, compared to the thumb metacarpal portion 115 in the position of FIG. 17A(1) and 17A(2), the thumb metacarpal portion 115 in the position of FIG. 17B(1) and 17B(2) can rotate around the thumb CM joint 1011 of the thumb metacarpal portion 115 in a wider range of motion by the rotation range expanded by the expansion portion 1300 than the very narrow rotation range determined, for example, by the cavity width of the index finger metacarpal portion 125, and can rotate so as to stand up vertically to the paper surface of the drawing.

[0109] FIG. 18 is an example of an explanatory diagram illustrating the connection state of the metacarpal portion 10 of each finger portion 30. FIG. 18(A) illustrates a state in which the thumb metacarpal portion 115, the index finger metacarpal portion 125, the middle finger metacarpal portion 135 (the central member 200), and the little finger metacarpal portion 155 are connected. FIG. 18(B) illustrates a state in which the thumb metacarpal portion 115, the index finger metacarpal portion 125, the middle finger metacarpal portion 135 (the central member 200), and the little finger metacarpal portion 155 are separated. FIG. 18(C) illustrates an example of a hinge connection portion 1000 that connects the metacarpal portions 10 of the fingers 30.

[0110] Each hinge connection portion 1000 may be oriented with its longitudinal direction at an angle relative to the direction of the central axis 230 of the central member 200. This allows for a better reproduction of the range of motion of a human hand, which has metacarpal bones of each finger that radiate slightly and connect with the CM joints, despite being a completely different configuration from the anatomical configuration of the human hand.

[0111] For example, by rotating the finger metacarpal portion 10 around the hinge connection portion 1000, the entire metacarpal portion 10 can take on states such as those described in the following Figures 19 and 20, thereby enabling the hand model 1 to more accurately imitate the movement, posture, and shape of an actual hand.

[0112] FIG. 33 is another example of an explanatory diagram illustrating the connection state of the metacarpal portion 10 of each finger portion 30. FIG. 33(A) illustrates a state in which the thumb metacarpal portion 115, the index finger metacarpal portion 125, the middle finger metacarpal portion 135 (central member 200), and the little finger metacarpal portion 155 are separated. Figure 33(B) shows the outer part 220 of the CM joint 20 of the middle finger metacarpal part 135 (central member 200) in the embodiment of Figure 33(A) viewed from the back of the hand toward the palm. Figure 33(C) shows the outer part 220 of the CM joint 20 of the middle finger metacarpal part 135 (central member 200) in the embodiment of Figure 33(A), viewed in the direction from the distal end side to the proximal end side of the middle finger metacarpal part 135.

[0113] Unlike the embodiment of FIG. 18, the embodiment of FIG. 33 includes spherical connections 3310, shown schematically by dashed circles, between the middle finger metacarpal portion 135 and the ring finger metacarpal portion 145, and between the ring finger metacarpal portion 145 and the little finger metacarpal portion 155, respectively. As the spherical connecting portion 3310, a ball joint, a joint member for the IP joint portion 50, which will be described in detail with reference to FIG. 28, or the like can be used.

[0114] For example, in a configuration in which a joint member for the IP joint portion 50 is used as the spherical connection portion 3310, the joint member for the IP joint portion 50 can be attached in a state rotated by approximately 90° relative to the IP joint portion 50 of each finger portion 30 so that the rotation direction corresponds to that of the hinge connection portion 1000, thereby achieving the same rotation direction as that of the hinge connection portion 1000. 28 is fixedly housed in a recess (not shown) provided in the middle finger metacarpal portion 135, and similarly, a component corresponding to the distal connection portion 2821 is fixedly housed in a recess (not shown) provided in the ring finger metacarpal portion 145. Note that the component corresponding to the proximal connection portion 2811 may be attached to the ring finger metacarpal portion 145, and the component corresponding to the distal connection portion 2821 may be attached to the middle finger metacarpal portion 135.

[0115] Similarly, the hinge connection portion 1000 between the index finger metacarpal portion 125 and the middle finger metacarpal portion 135 can also be replaced with a spherical connection portion 3310 (for example, a joint member for the IP joint portion 50), but a configuration using the hinge connection portion 1000 makes it easier to ensure a larger possible rotation range or rotation space for the rotation of the thumb metacarpal portion 115 described above.

[0116] Furthermore, in the embodiment of Figure 33(A), the little finger metacarpal portion 155 has a third support protrusion 3320. The third support protrusion 3320 plays a role in supporting the little finger metacarpal portion 155, similar to the first support protrusion 226 and the second support protrusion 227 described using Figure 2. For this reason, a third support protrusion insertion hole 3330 is provided in a corresponding position on the lateral part 220 of the CM joint 20, as shown in Figures 33(B) and 33(C).

[0117] Whether the first to third support protrusions 226, 227, 3320 and the first to third support protrusion insertion holes 1810, 1820, 3330 are provided on the metacarpal portion 10 of each finger or on the CM joint side can be changed depending on the design. Furthermore, the length, shape (e.g., cylindrical, truncated cone, etc.), size (e.g., diameter and width) of the first to third support protrusions 226, 227, 3320, and the position of each finger metacarpal portion 10 and each CM joint portion 20 on the outer portion 220 can be designed according to the design of the range of motion and non-movement of each component of the hand model 1, in particular each finger metacarpal portion 10 and each finger portion 30, their ease or difficulty of movement based on frictional force, etc. Similarly, the depth and shape (circular, elliptical, linear, curved, etc.) of the first to third support protrusion insertion holes 1810, 1820, 3330, and the position of each finger metacarpal portion 10 and each CM joint portion 20 on the outer portion 220 can also be designed according to the design of the range of motion and non-movement of each component of the hand model 1, in particular each finger metacarpal portion 10 and each finger portion 30, and their ease or difficulty of movement based on frictional force, etc.

[0118] For example, in a configuration in which the first to third support protrusions 226, 227, 3320 are in contact with the first to third support protrusion insertion holes 1810, 1820, 3330 and sufficient frictional force is generated between them, the index finger metacarpal portion 125, the ring finger metacarpal portion 145, and the little finger metacarpal portion 155 can stably maintain their positional relationship with the outer portion 220 of the CM joint portion 20 against, for example, vibrations, impacts, changes in acceleration, etc. that accompany movement or transportation of the hand model 1. This allows the shape of the hand model 1 to be stably maintained, even when the hand model 1 is moved from a preparation room to an art room for use as a drawing model, etc. As a result, a student can resume drawing using the hand model 1 in the same state as the previous time they drew.

[0119] In this way, by using the hinge connection portion 1000 in combination with the spherical connection portion 3310, and by appropriately setting the mounting positions and dimensions of the first to third support protrusions and the first to third support protrusion insertion holes, the embodiment of Figure 33(A) can imitate the range of motion and non-motion of a human hand with higher reproducibility than the embodiment of Figure 18, and can stably maintain that state.

[0120] FIG. 19 is an example of an explanatory diagram illustrating the metacarpal portion 10 in a flatter state. Figure 19(A) is a view of the back of the hand showing the metacarpal portions 10 of the four fingers (index finger, middle finger, and little finger) in a flatter state (hereinafter also referred to as "four-finger metacarpal portions 10"). The metacarpal portions 10 of each finger portion 30 are closer to each other than in the embodiment shown in Figure 20(A) described below. It is preferable that the metacarpal portions 10 of each finger portion 30 are in contact with each other.

[0121] 19(B) is a view of the four-finger metacarpal part 10 in a flatter state, viewed from the fingertip side toward the wrist side. A first imaginary curve 1910 is an imaginary curve passing near the center of the MP joint accommodating recess 1900 provided in each of the four-finger metacarpal part 10. The first virtual curve 1910 roughly represents the bending of the four-finger metacarpal portion 10 in the state of Fig. 19. This allows the bulge of a human hand to be reproduced more satisfactorily.

[0122] In the hand model 1 according to the embodiment of FIG. 19(B), the first virtual curve 1910 is represented as a curve that is convex upward in the figure, that is, that is, that is, that is, that is, that is, that is, a curve that is convex from the palm to the back of the hand, but depending on the design of the hand model 1, it may be a straight line.

[0123] Furthermore, in designing the hand model 1, the first virtual curve 1910 can be made to be a curve that is convex downward in the figure, that is, that is, that is, that is, that is, that is, a curve that is convex from the back of the hand toward the palm. However, when reproducing the structure of a human hand, for example, it is better to avoid such a structure, as this will increase realism.

[0124] FIG. 19(C) is an example of an external view of the hand model 1 when the entire metacarpal portion is in the posture shown in FIG. 19(A) and FIG. 19(B). In the embodiment of FIG. 19(C), the palm portion of the metacarpal portion 10 of the hand model 1 is in relatively tight contact with the installation surface.

[0125] FIG. 20 is an example of an explanatory diagram illustrating the metacarpal portion 10 in a more curled state. Figure 20(A) is a view of the back of the hand of the four-finger metacarpal unit 10 in a more curled state. The metacarpal units 10 of each finger unit 30 are spaced farther apart than in the embodiment of Figure 19(A) described below. In Figure 20(A), there is a slight gap 2000 between the metacarpal units 10 of each finger unit 30 along each metacarpal unit 10.

[0126] 20(B) is a view of the four-finger metacarpal portion 10 in a more curled state, viewed from the fingertip side toward the wrist side. Similar to the first virtual curve 1910, the second virtual curve 2010 is a virtual curve that passes near the center of the MP joint accommodating recess 1900 provided in each of the four-finger metacarpal portion 10.

[0127] A second imaginary curve 2010 schematically represents the bending of the four-finger metacarpal portion 10 in the state shown in Figure 20. The second imaginary curve 2010, also shown in Figure 20(B), has a greater curvature than the first imaginary curve 1910 in Figure 19(B).

[0128] A larger curvature of the second virtual curve 2010 compared to the first virtual curve 1910 can be achieved by rotating each finger metacarpal portion 10 around the hinge connection portion 1000 shown in FIG. 18(C), thereby enabling a good reproduction of the bulge of the human hand.

[0129] 20(B), the hand model 1 has the above-described structure such that the innermost point 2020 of the little finger metacarpal portion 155, which is the innermost point (the point closest to the central axis 230) of the little finger metacarpal portion 155, has moved toward the central axis 230 to the range of the middle finger metacarpal portion 135. In this case, it is more preferable that the little finger metacarpal portion 155 be configured to be able to come into contact with the thumb metacarpal portion 115, which has also rotated toward the central axis 230, as shown in FIG. 15(D), for example.

[0130] With this configuration, the hand model 1 can reproduce the state in which the ball of the thumb and the ball of the little finger come into contact when the tip of the thumb and the tip of the little finger come into contact with each other on a human hand.

[0131] FIG. 20(C) is an example of an external view of the hand model 1 when the entire metacarpal portion 10 is in the position shown in FIG. 20(A) and FIG. 20(B). In the embodiment of FIG. 20(C), the palm of the hand model 1 is slightly separated from the installation surface by the entire metacarpal portion 10, and mainly each finger portion 30 is in contact with the installation surface.

[0132] FIG. 21 is an explanatory diagram illustrating an example of the configuration of the finger portion 30. FIG. 21(A) is a view of the thumb portion 110, the thumb metacarpal portion 115, the middle finger portion 130, and the central member 200 as viewed from the back of the hand. The middle finger area 2120 of FIG. 21(A) is described in more detail in FIG. FIG. 21(B) is a view of the thumb portion 110, the thumb metacarpal portion 115, the middle finger portion 130, and the central member 200 as viewed from the palm side.

[0133] In Figures 21(A) and 21(B), the index finger portion 120, the ring finger portion 140, the little finger portion 150, and their metacarpal portions are not shown, but the following description of the middle finger portion 130 can be applied to each of these finger portions 30 in the same manner.

[0134] FIG. 22 is an example of an explanatory diagram illustrating the middle finger area 2120 of FIG. In FIG. 22, the middle finger portion 130 surrounded by the middle finger area 2120 in FIG. 21 and the tip portion of the central member 200 to which the middle finger portion 130 is connected are shown in a separated state.

[0135] An MP joint 40 is provided between the distal end of the middle finger metacarpal part 135 and the middle finger proximal phalanx 2101, and the MP joint 40 connects the middle finger proximal phalanx 2101 to the middle finger metacarpal part 135 so that the middle finger can rotate in the flexion-ulnar flexion directions and the dorsiflexion-palmar flexion directions.

[0136] Note that rotation in the flexion and ulnar flexion directions means rotation of the middle finger proximal phalanx 2101 in the flexion direction from the little finger portion 150 to the thumb portion 110 relative to the middle finger metacarpal portion 135, and rotation of the middle finger proximal phalanx 2101 in the ulnar flexion direction from the thumb portion 110 to the little finger portion 150 relative to the middle finger metacarpal portion 135. Furthermore, rotation in the dorsiflexion and palmar flexion directions means rotation in the dorsiflexion direction in which the middle finger proximal phalanx 2101 bends upward toward the back of the hand relative to the middle finger metacarpal portion 135, and rotation in the palmar flexion direction in which the middle finger proximal phalanx 2101 bends toward the palm relative to the middle finger metacarpal portion 135.

[0137] A PIP joint 51 is provided between the middle finger proximal phalanx 2101 and the middle finger medial phalanx 2102. The PIP joint 51 connects the middle finger medial phalanx 2102 to the middle finger proximal phalanx 2101 so that the middle finger medial phalanx 2102 can rotate in the dorsiflexion and palmar flexion directions, while restricting rotation in the flexion and ulnar flexion directions.

[0138] Similarly, a DIP joint 52 is provided between the middle finger medial phalanx 2102 and the middle finger distal phalanx 2103, and the DIP joint 52 connects the middle finger distal phalanx 2103 to the middle finger medial phalanx 2102 so that the middle finger distal phalanx 2103 can rotate in the dorsiflexion and palmar flexion directions, while restricting rotation in the flexion and ulnar flexion directions.

[0139] FIG. 23 is an example of an explanatory diagram illustrating the MP joint portion 40. FIG. 23(A) shows the MP joint 40 as viewed from the back of the hand. FIG. 23(B) shows the MP joint 40 as viewed in the direction from the ring finger 140 to the index finger 120. FIG. 23(C) shows the components of the MP joint portion 40 in an exploded view.

[0140] A portion of the MP joint base 2300 is fixedly attached to and housed in the MP joint housing recess 1900 provided at the distal end of each finger metacarpal portion 10. A first rotation part (MP joint flexor-ulnar flexor) 2310 of the MP joint section 40 is attached to the MP joint base 2300 via a second rotation part (MP joint dorsi-palmar flexor) 2320 of the MP joint section 40. Although detailed explanation will be omitted, the MP joint base 2300 and the first rotation part (MP joint flexor-ulnar flexor) 2310 are each formed by combining a plurality of members, and are assembled by sandwiching the second rotation part (MP joint dorsi-palmar flexor) 2320.

[0141] The distal connection portion 2311 of the first rotation portion 2310 of the MP joint 40 is fixedly attached to and housed in a recess provided at the proximal end of each finger proximal phalangeal portion 31. The MP joint portion 40 is configured to be capable of flexion rotation and ulnar rotation in a fourth rotation direction RD4 around the second rotation support portion 2322. Although detailed description will be omitted, the second rotation support portion 2322 is formed in a rivet shape and is configured to be fitted into a recess provided in the second rotation portion 2320, thereby connecting to the first rotation portion 2310. Furthermore, although not shown in FIG. 23 , the front surface of the second rotation support portion 2322 is covered by the base joint portion 31, and when connecting to the first rotation portion 2310 by the base joint portion 31, the second rotation support portion 2322 is not necessarily provided.

[0142] The MP joint 40 is configured to be capable of dorsiflexion rotation and palmar flexion rotation around the first rotation support portion 2302 in a fifth rotation direction RD5. The specific rotational states of the first rotation portion 2310 of the MP joint portion 40 and the second rotation portion 2320 of the MP joint portion 40 will be described below with reference to FIGS. 24 to 28. FIG.

[0143] FIG. 24 is an example of an explanatory diagram illustrating the rotation of the MP joint portion 40. FIG. 24(A) shows the central member 200 and the middle finger proximal phalanx 2101 in a state in which the MP joint 40 is bent, that is, the state in which the middle finger proximal phalanx 2101 has rotated toward the thumb, together with an enlarged view of the MP joint 40 in that state. FIG. 24(B) shows the central member 200 and the proximal phalanx 2101 of the middle finger in the bent state shown in FIG. 24(A) as viewed from the palm side.

[0144] The rotation range of the MP joint 40 is determined on the one hand by the configuration of the MP joint 40 itself, and on the other hand by the shape of the distal end contour 2200 of the middle finger metacarpal portion 135 and the proximal end contour 2210 of the middle finger proximal phalanx portion 2101.

[0145] The rotation of the MP joint 40 is, for example, a rotational movement that combines palmar flexion and dorsiflexion, which are pitch rotations relative to the longitudinal direction of the proximal phalanx 2101 of the middle finger, and flexion and ulnar flexion, which are yaw rotations. The rotation of the MP joint 40 changes the magnitude of the possible yaw angle based on the deviation of the pitch angle from 0°. Regarding the rotation of the MP joint portion 40, the larger the deviation of the pitch angle from 0°, the smaller the possible yaw angle becomes.

[0146] The possible change in yaw angle depending on the magnitude of deviation of the pitch angle from 0° can be realized by, in particular, designing the distal end contour 2200 of the middle finger metacarpal portion 135 and the proximal end contour 2210 of the middle finger proximal phalanx portion 2101 so that they come into contact at a smaller yaw angle as the deviation of the pitch angle from 0° increases. The above configuration is the same for each of the fingers 110, 120, 140, and 150 other than the middle finger 130.

[0147] In particular, it is preferable that the rotation range of the flexion and ulnar flexion of the MP joint 40 is maximum when the dorsiflexion and palmar flexion of the MP joint 40 is 0°, and decreases as the dorsiflexion and palmar flexion of the MP joint 40 increases, thereby more effectively reproducing the range of motion and immobility of a human finger.

[0148] The above rotation range can be realized by the fact that the larger the dorsiflexion / palmar flexion rotation of the MP joint 40, the more the distal end contour 2200 of the metacarpal portion 135 of the middle finger and the proximal end contour 2210 of the proximal phalanx portion 2101 of the middle finger come into contact with each other in a narrower range of flexion / ulnar flexion rotation, thereby preventing further flexion / ulnar flexion rotation.

[0149] FIG. 25 is an example of an external view of the hand model 1 for explaining flexion and ulnar flexion of the middle finger 130. FIG. 25(A) is an example of an external view of a hand model 1 in which the flexion and ulnar flexion angles of the middle finger 130 are approximately 0°. In Figures 25(A), 25(B), and 25(C), the index finger 120 is flexed, and the ring finger 140 and little finger 150 are ulnarly flexed.

[0150] FIG. 25(B) is an example of an external view of the hand model 1 in which the middle finger portion 130 is bent. FIG. 25(C) is an example of an external view of hand model 1 in which middle finger 130 is flexed.

[0151] FIG. 26 is an example of an explanatory diagram illustrating the rotation of the MP joint portion 40. Figure 26(A) shows the central member 200 and the middle finger proximal phalanx 2101 in a state where the MP joint 40 is palmarly flexed, that is, where the middle finger proximal phalanx 2101 has rotated toward the palm, together with an enlarged view of the MP joint 40 in that state, viewed from the thumb side toward the little finger side.

[0152] Figure 26(B) shows the central member 200 and the middle finger proximal phalanx 2101 with the MP joint 40 dorsiflexed, that is, with the middle finger proximal phalanx 2101 rotated toward the back of the hand, as viewed from the thumb side toward the little finger side.

[0153] The range of rotation of the MP joint 40 for palmar flexion in the state of FIG. 26(A) and the range of rotation of the MP joint 40 for dorsiflexion in the state of FIG. 26(B) may be determined based on the shapes of the distal end contour 2200 of the middle finger metacarpal portion 135 and the proximal end contour 2210 of the middle finger proximal phalanx portion 2101 and by their contact. In other words, it is preferable that the MP joint 40 can be palmarly flexed and dorsiflexed until the middle finger metacarpal portion 135 and the middle finger proximal phalanx portion 2101 come into contact with each other and stop.

[0154] Additionally or alternatively, the rotation range of the MP joint 40 for palmar flexion and dorsiflexion may be designed based on the configuration of the MP joint 40 itself, which will be described with reference to FIG.

[0155] In particular, it is preferable that the rotation range of the MP joint 40 for palmar flexion is designed to be larger than the rotation range of the MP joint 40 for dorsiflexion, thereby making it possible to more effectively reproduce the range of motion and non-motion of a human finger.

[0156] FIG. 27 shows examples of external views of the hand model 1 in which the rotation amount of the MP joint portion 40 is different. FIG. 27(A) is an example of an external view of the hand model 1 in a state where the MP joints 40 of the fingers 30 are palmarly flexed by approximately 90°. FIG. 27(B) is an example of an external view of the hand model 1 in a state where the MP joints 40 of the fingers 30 are palmarly flexed at an angle of approximately 30° to 45°.

[0157] The MP joint 2710 of the little finger and the MP joint 2720 of the ring finger in the hand model 1 in Figure 27(B) are slightly more palmarly flexed than the MP joint 2710 of the little finger and the MP joint 2720 of the ring finger in the hand model 1 in Figure 27(A). Furthermore, the MP joint 2720 of the ring finger in the hand model 1 of FIG. 27(B) is slightly more palmarly flexed than the MP joint 2710 of the little finger.

[0158] In both the hand models 1 of FIG. 27(A) and FIG. 27(B), the PIP joint 2730 of the little finger and the PIP joint 2740 of the ring finger are both in almost complete palmar flexion. The DIP joint 2750 of the little finger in Fig. 27(B) is approximately straight and is more palmarly flexed than the DIP joint 2750 of the little finger in Fig. 27(A), which is barely palmarly flexed or dorsiflexed. As a result, the middle joint 2760 of the little finger in Fig. 27(B) stands higher from the installation surface than the middle joint 2760 of the little finger in Fig. 27(A). The same is true for the middle finger 130.

[0159] 27(A) and 27(B) are examples of postures that the hand model 1 can take. By individually moving the MP joints 40 and IP joints 50 of each finger 30, the user can easily and variably change the posture of the hand model 1. In particular, it is possible to continuously reproduce or imitate postures that can be expressed by an actual human hand, from very slight changes to very large changes.

[0160] FIG. 28 is an example of an explanatory diagram illustrating the configuration of the IP joint portion 50. FIG. 28(A) shows the IP joint portion 50 in an assembled state and the IP joint portion 50 in a disassembled state, viewed from the back of the hand toward the palm.

[0161] The IP joint portion 50 is composed of an IP joint fixing portion 2810 that is fixedly connected to the proximal middle joint portion 32 and the proximal joint portion 31 at a proximal connection portion 2811, and an IP joint rotating portion 2820 that is fixedly connected to the distal end joint portion 33 and the middle joint portion 32 at a distal connection portion 2821.

[0162] The IP joint rotation portion 2820 has a rotation shaft 2823, and can rotate around it together with the distal joint portion 33 and the middle joint portion 32, which are fixedly connected via a distal connection portion 2821. Note that by providing play (space) between the rotation shaft 2823 and the distal connection portion 2821, the IP joint portion 50 may be configured to be able to flex and ulnarally flex.

[0163] The IP joint fixing portion 2810 has a fixing portion protrusion 2812. The fixing portion protrusion 2812 comes into contact with a rotating portion step 2822 of the IP joint rotating portion 2820, thereby restricting further rotation of the IP joint rotating portion 2820.

[0164] 28(B) is a view of the IP joint portion 50 of FIG. 28(A) viewed in the axial direction of the rotation shaft body 2823. FIG. A rotation range 2824 is provided between the two rotation step portions 2822 of the IP joint rotation portion 2820. The two rotation portion steps 2822 correspond to the maximum palmar flexion rotation position and the maximum dorsiflexion rotation position of the IP joint rotation portion 2820, respectively.

[0165] It is preferable that the positions of the two rotational portion steps 2822 and the size of the rotation range 2824 are the same, since this allows for cheaper and easier manufacturing and assembly. However, the positions of the two rotation step portions 2822 and the size of the rotation range 2824 may be designed differently for each finger portion 30 to provide more variations.

[0166] FIG. 28(C) is a view showing the state in which the IP joint portion 50 in FIG. 28(A) is palmarly flexed, as viewed in the axial direction of the rotation shaft body 2823. The position 2813 of the fixing portion protrusion 2812 represented by a dashed square in Figures 28(B) and 28(C) indicates the position of the fixing portion protrusion 2812 of the IP joint fixing portion 2810 within the rotation range 2824 in each rotation state.

[0167] The embodiment of Figure 28 can also be modified to a configuration in which the IP joint fixing portion 2810 is fixedly connected to the distal joint portion 33 or the middle joint portion 32 on the distal side, and the IP joint rotating portion 2820 is fixedly connected to the middle joint portion 32 or the proximal joint portion 31 on the proximal side.

[0168] FIG. 29 is an example of an explanatory diagram illustrating dorsiflexion and palmar flexion of the DIP joint portion 52. Figure 29(A) shows the middle and distal segments 32 and 33 with the DIP joint 52 in a dorsiflexed state, i.e., with the distal segment 33 rotated in a palmar flexion toward the back of the hand, together with an enlarged view of the DIP joint 52 in that state.

[0169] Figure 29(B) shows the middle and distal segments 32 and 33 in a state in which the DIP joint 52 is flexed, i.e., the distal segment 33 is dorsiflexed and rotated toward the palm, together with an enlarged view of the DIP joint 52 in that state.

[0170] In FIG. 29(A), the DIP joint 52 has rotated to approximately the maximum dorsiflexion rotation position. In FIG. 29(B), the DIP joint 52 has rotated to approximately the maximum palmar flexion rotation position. The distal end contour 2920 of the middle joint portion 32 and the proximal end contour 2930 of the distal joint portion 33 may be designed to be in close contact with each other at the maximum dorsiflexion rotation position and the maximum palmar flexion rotation position. In addition, instead of or in addition to the configuration that limits the rotation range by contact with the fixed portion protrusion 2812 and the rotating portion step 2822 described above, it is also possible to apply a configuration that limits the rotation range by contact between the middle segment distal end contour 2920 and the distal segment proximal end contour 2930.

[0171] FIG. 30 is an example of an external view of the hand model 1 for explaining the range of motion of the MP joint portion 40 and the IP joint portion 50. 30, the index finger 120 of the hand model 1 is entirely dorsiflexed, with the degree of dorsiflexion being particularly large at the proximal phalanx 31 and the distal phalanx 33. The index finger 120 is also ulnarly flexed, pointing towards the back of the drawing.

[0172] The middle finger portion 130 is not substantially flexed / ulnarly flexed, nor is it dorsiflexed / palmar flexed, and is extended substantially straight. The entire ring finger 140 is in palmar flexion, and the distal joint 33 of the ring finger 140 is in contact with the distal joint 33 of the thumb 110.

[0173] The little finger portion 150 is more palmarly flexed than the ring finger portion 140 as a whole. Since each finger portion 30 can independently perform flexion / ulnar flexion and dorsiflexion / palmar flexion, the hand model 1 can very well imitate and reproduce the movement, shape, and pose of a human hand.

[0174] Another variation of the hand shape that can be realized by the hand model 1 according to this embodiment will be further described below with reference to FIG. FIG. 31 is another example of an external view of the hand model 1 for explaining an example of the range of motion of the MP joint portion 40 and the IP joint portion 50.

[0175] FIG. 31(A) is an example of an external view of the hand model 1 in a state where the index finger 120 and the middle finger 130 are crossed. FIG. 31(B) is an example of an external view of the hand model 1 in the state of FIG. 31(A) viewed from the thumb side toward the little finger side.

[0176] 31, the MP joint 3110 of the index finger 120 is ulnar flexion, and the MP joint 3120 of the middle finger 130 is flexed and palmar flexion. As a result, the index finger 120 and the middle finger 130 cross each other. Additionally, the DIP joint 3115 of the index finger 120 is palmarly flexed, and the DIP joint 3125 of the middle finger is dorsiflexed. As a result, the crossed index finger 120 and middle finger 130 form a loop (void).

[0177] In this way, the hand model 1 can very well imitate and reproduce the movement, shape, and pose of a human hand, making it possible to achieve a highly realistic representation when depicting the shape of a hand by referencing the hand model. In the above embodiment, in order to achieve a range of motion similar to that of the anatomical structure of a human arm or hand, the range of motion is limited by contact between adjacent members (for example, the metacarpal portion 10 and the proximal joint portion 31 sandwiching the MP joint portion 40) via a joint. In this way, the range of motion can be appropriately adjusted by fine-tuning the shape of the end of each member.

[0178] Furthermore, in the above embodiment, for the sake of convenience, gaps are provided in the rotating parts of each joint and hinge connection part, but in the actual hand model 1, it is desirable to have the members of the rotating parts abut each other without providing gaps, so that the rotation angles of the joints can be maintained in a fixed state by frictional force or the like, even if the user releases their hand after setting each joint of the hand model 1. In that case, it is preferable to abut the CM joint 20 and the thumb CM joint 1011 particularly firmly, because they are subjected to a large load in order to support the members beyond them.

[0179] 32 , for the CM joint portion 20, the outer portion 220 may be composed of a plurality of members, for example, a first half 3210 and a second half 3220 of the outer portion 220, and cylindrical members, for example, a first cylindrical member 3211 and a second cylindrical member 3221, may be provided inside each member so as to protrude perpendicularly in the second rotation direction RD2, so as to pass through a cylindrical member insertion hole 3230 in the inner portion 300, and the two cylindrical members 3211 and 3221 may be joined with screws or the like, and the two cylindrical members 3211 and 3221 may be configured to move closer to each other by tightening the screws or the like, thereby making it possible to adjust the contact force between the outer portion 220 and the inner portion 300. In this way, the person using the hand model may be able to adjust the strength of the contact themselves.

[0180] In this configuration, a long cylindrical member insertion hole 3230 may be provided in the portion of the inner part 300 through which the cylindrical members 3211, 3221 are inserted so as not to hinder the rotation of the inner part 300. Furthermore, with regard to the thumb CM joint 1011, in addition to the abutment between the lateral part 221 and the inner part 1020, a member that covers and abuts the lateral part 221 may be provided on the thumb metacarpal part 115, thereby making the abutment force between the lateral part 221 and the inner part 1020 stronger. In the above embodiment, each member of each joint is described as being integral, but it may be configured as being made up of multiple members, which makes it easier to adjust the frictional force when they are in contact.

[0181] 1A to 31, the individual components of the hand model 1 are exposed for the sake of explanation, but they may be covered, for example, with a film structure made of resin or the like as a pseudo-skin structure. In such an embodiment, the appearance of the hand model 1 can be made to more closely resemble the appearance of a human hand. Additionally or alternatively, the hand model 1 may be covered with a clothing structure (such as a glove) made of cloth, fabric, or the like.

[0182] Furthermore, by providing a fixing member insertion hole 710 on the upper end surface of the arm end 60 in Figure 7(A), for example, by inserting a rod-shaped fixing member provided on a base into the fixing member insertion hole 710, it becomes possible to fix the hand model 1 at an angle other than the angle at which the fingers are positioned upward relative to the wrist, thereby improving convenience as a sketch sample when drawing a hand.

[0183] Furthermore, when using hand model 1 as a prosthetic hand, it is possible to naturally and stably imitate and reproduce various hand shapes and postures that may occur in daily life, such as combining the fingers of both hands, pointing with the prosthetic hand (hand model 1), or resting one's chin on one's hand. This not only makes it difficult for people around to notice that it is a prosthetic hand, but also improves the user's quality of life (QOL).

[0184] Furthermore, the hand model 1 may include a drive unit or actuator capable of mechanically or electrically controlling and driving at least one of the above-described components, particularly at least one joint. Such a hand model 1 can also be used as a robot hand, a robot arm, a manipulator, an electric prosthetic hand, or the like. Even in such uses, the hand model 1 can reproduce the shape and posture of human fingers very well. Furthermore, depending on the output of the drive unit or actuator and the strength of each component, it may actually be possible to pinch or grasp an object.

[0185] For example, a user can use, as a prosthetic hand, a hand model 1 configured with a drive unit that can mechanically and electrically control and drive the MP joint 40 and IP joint 50 of the index finger 120. In such a case, the user can naturally change the state of the hand model 1 from a clenched hand state to a pointing hand state, which significantly improves convenience in daily life.

[0186] In such a configuration, the driving unit electrically connected to a battery, a communication device, a processing device, etc. is controlled based on specific bioelectrical signals, such as electroencephalography (EEG) and skin potentials of the prosthetic arm wearer, acquired by a detection device such as a wearable sensor. The specific signal may be a characteristic signal that occurs, for example, when the prosthetic arm wearer thinks about "pointing" or when the wearer actually contracts the muscles of the arm to point. The specific bioelectrical signal detected by the detection device is sent to the processing device via the communication device, and the processing device then operates the driving unit based on the received specific bioelectrical signal. This allows the prosthetic arm wearer to change the hand model 1, for example, from a clenched hand position to a pointing position, without operating a physical switch or the like. The above configuration is particularly suitable for use in the index finger MP joint 3110 of the hand model 1 used as a prosthetic hand, and it is even better if the index finger MP joint 3110 can be rotated by a motor housed in the proximal joint 31 of the index finger 120 or in the distal end region of the index finger metacarpal part 125, for example.

[0187] The present invention is not limited to the above-described embodiments and includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations.

[0188] The above-described embodiments disclose at least the configurations described in the claims.

[0189] The present invention also includes at least the following Examples (1) to (23). The present invention further includes a configuration in which the following Examples (1) to (23) are combined.

[0190] Example (1) It has a central part consisting of the CM joint and the middle finger metacarpal part, The CM joint portion comprises a first lateral portion and a first medial portion, the first outer portion rotatably accommodates the first inner portion; the first outer portion has at least one guide portion; The guide portion of the first outer portion limits the rotation of the first inner portion about one of the three rotation axes. Hand model.

[0191] Example (2) the first inner portion has at least one guide protrusion; The guide portion limits the rotation of the one axis by limiting the movement of the guide protrusion within the guide portion. Hand model.

[0192] Example (3) the outer portion has, as the guide portion, a first guide portion sandwiched between a first guide edge and a second guide edge; The outer portion limits the movement of the guide protrusion by contact between the guide protrusion and the first guide edge or the second guide edge within the first guide portion, thereby limiting the rotation of the inner portion about the single axis. Hand model.

[0193] Example (4) The guide protrusion contacts the first guide edge or the second guide edge on the back side or palm side of the outer part. Hand model.

[0194] Embodiment (5) The first inner portion has a first guide protrusion and a second guide protrusion as the guide protrusions, the first guide protrusion contacts the first guide edge or the second guide edge on the back side or palm side of the outer portion; The second guide protrusion contacts the first guide edge or the second guide edge on the opposite side to the first guide protrusion. Hand model.

[0195] Example (6) the outer portion has, as the guide portion, a second guide portion sandwiched between a third guide edge and a fourth guide edge; the first inner portion has at least one connecting portion; The outer portion accommodates both or one of the first guide protrusion and the second guide protrusion within the first guide portion depending on the position of the connection portion within the range of the second guide portion. Hand model.

[0196] Example (7) The first inner portion is connected to the arm end portion via the connecting portion. Hand model.

[0197] Example 8 The rotation of one axis that is restricted is a roll rotation about a rotation axis that passes through the center of the inner portion and extends in the longitudinal direction of the central member. The hand model according to claim 1.

[0198] Example 9 The CM joint portion has a thumb CM joint portion, The thumb CM joint has a second lateral part fixedly attached to the first lateral part, and a second medial part rotatably housed within the second lateral part and connected to the thumb metacarpal part. Hand model.

[0199] Example (10) The second outer portion at least partially accommodates the second inner portion so as to be rotatable about three axes. Hand model.

[0200] Example (11) The middle finger metacarpal portion is connected to the index finger metacarpal portion, The index finger metacarpal portion has a stopper wall portion, the middle finger metacarpal portion includes an inner wall portion; The range of rotation of the thumb metacarpal portion about the three axes is limited by contact with at least one of the stopper wall portion and the inner wall portion. Hand model.

[0201] Example (12) The thumb metacarpal portion can assume a first position and a second position based on rotation, In the first position, the range of rotation about the three axes is limited by contact with the stopper wall portion, In the second position, the range of rotation about the three axes is limited by contact with the stopper wall portion and the inner wall portion. Hand model.

[0202] Example (13) the thumb metacarpal portion has a contact protrusion; The range of rotation of the thumb metacarpal portion about the three axes is limited by contact with the contact protrusion and the stopper wall portion. Hand model.

[0203] Example 14 the thumb metacarpal portion has an extension, and the contact protrusion is provided on the extension; The extension is at least partially receivable within the thumb metacarpal portion. Hand model.

[0204] Example 15 The contact protrusion is not housed within the thumb metacarpal portion. Hand model.

[0205] Example (16) The expansion portion is capable of transitioning from a stowed state to an expanded state while the contact protrusion remains in contact with the metacarpal portion of the index finger. Hand model.

[0206] Example 17 The middle finger metacarpal portion is connected to the index finger metacarpal portion via a first pivot connection portion and to the ring finger metacarpal portion via a second pivot connection portion; the ring finger metacarpal portion is connected to the little finger metacarpal portion via a third pivot connection portion; The thumb metacarpal portion and the little finger metacarpal portion can come into contact with each other based on the rotational states of the first rotational connection portion to the third rotational connection portion and the thumb CM joint portion. Hand model.

[0207] Example 18 The middle finger metacarpal portion is directly or indirectly connected to the thumb metacarpal portion, the index finger metacarpal portion, the ring finger metacarpal portion, and the little finger metacarpal portion; At least one of these metacarpals is connected to the proximal phalanx of each finger via the MP joint, The proximal joint can rotate about at least two axes via the MP joint. Hand model.

[0208] Example 19 The two-axis rotation is a combination of pitch rotation and yaw rotation relative to the longitudinal direction of the base joint portion, The amount of yaw angle that can be rotated around the two axes changes based on the deviation of the pitch angle from 0°. Hand model.

[0209] Example (20) The greater the deviation of the pitch angle from 0°, the smaller the yaw angle that can be rotated around the two axes. Hand model.

[0210] Example 21 The distal end of the metacarpal portion of each finger and the proximal end of the proximal phalangeal portion of each finger come into contact at a smaller yaw angle as the pitch angle deviates from 0°, thereby limiting the rotation of the two axes. Hand model.

[0211] Example 22 A central member consisting of a CM joint and a middle finger metacarpal part; The CM joint portion has a first lateral portion and a thumb CM joint portion, The thumb CM joint has a second lateral part fixedly attached to the first lateral part, and a second medial part rotatably housed within the second lateral part and connected to the thumb metacarpal part. Hand model.

[0212] Example 23 It has a central part consisting of the CM joint and the middle finger metacarpal part, The middle finger metacarpal portion is directly or indirectly connected to the thumb metacarpal portion, the index finger metacarpal portion, the ring finger metacarpal portion, and the little finger metacarpal portion; At least one of these metacarpals is connected to the proximal phalanx of each finger via the MP joint, The proximal joint can rotate about at least two axes via the MP joint. Hand model. [Explanation of symbols]

[0213] 1...hand model, 10...metacarpal portion, 20...CM joint portion, 30...finger portion, 40...MP joint portion, 50...IP joint portion, 51...PIP joint portion, 52...DIP joint portion, 60...arm end portion, 220...outer portion of CM joint portion 20, 300...inner portion of CM joint portion 20, 400...first guide portion, 500...second guide portion, 1011...thumb CM joint portion, 1100...contact protrusion portion, 1300...extension portion

Claims

1. a central member consisting of a joint portion and a metacarpal portion; the articulation portion comprises a first outer portion and a first inner portion; the first outer portion rotatably accommodates the first inner portion; the first outer portion has at least one guide portion; The guide portion of the first outer portion limits the rotation of the first inner portion about one of three rotation axes. Hand model.

2. The joint portion includes a thumb joint portion, The thumb knuckle portion has a second lateral portion fixedly attached to the first lateral portion and a second medial portion pivotally received within the second lateral portion and connected to a thumb metacarpal portion. The hand model according to claim 1 .

3. a central member consisting of a joint portion and a metacarpal portion; the joint portion comprises a first lateral portion and a thumb joint portion; The thumb knuckle portion has a second lateral portion fixedly attached to the first lateral portion and a second medial portion pivotally received within the second lateral portion and connected to a thumb metacarpal portion. Hand model.

4. the thumb metacarpal portion has an extension; the extension portion is provided with a contact protrusion portion that can come into contact with a metacarpal portion other than the thumb metacarpal portion, The extension is at least partially receivable within the thumb metacarpal portion. The hand model according to claim 2 or 3.

5. At least one of the metacarpal portion and at least one other metacarpal portion directly or indirectly connected to the metacarpal portion is connected to a proximal phalanx portion of each finger portion via a second joint portion, The base joint portion is capable of rotating about at least two axes via the second joint portion. The hand model according to claim 1 or 3.

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