WALKING ASSISTANCE DEVICE

A walking assistance device includes a waist wearing belt, a thigh link portion, a lower leg link portion, a lower leg wearing portion mounted on the lower leg link portion, a waist joint portion configured to hold an upper end portion of the thigh link portion so that the thigh link portion swings and the waist joint portion being mounted on the waist wearing belt, and a knee joint portion configured to connect the thigh link portion and the lower leg link portion so that the thigh link portion and the lower leg link portion swing. The thigh link portion and the lower leg link portion have rigidity that is greater in the front-rear direction and an up-down direction than in a right-left direction so as to be elastically twisted around an axis along an elongated direction.

TECHNICAL FIELD

The present invention relates to a walking assistance device that is put on a person's leg to assist walking.

BACKGROUND ART

As is disclosed in Patent Document 1, a walking assistance device that is put on a person's leg to assist walking has been known. Such a walking assistance device is performed based on the principle of passive walking and is developed by the inventor of the present application. The passive walking is closest to the persons' natural walking motion and walking assistance devices using the passive walking motion are especially attracting attention.

Other type of a walking assistance device including an actuator such as an electric motor is described in patent Document 2. Unlike such a type of the walking assistance device, the above-described walking assistance device does not require an actuator such as an electric motor. The walking assistance device using the principle of passive walking described in patent Document 1 is configured as follows. Motion of the leg (a normal leg) that does not wear the walking assistance device is transferred to the walking assistance device via a user's (a wearer's) hip (pelvis) so that the walking assistance device is operated naturally to assist the user's walking motion. Therefore, such a walking assistance device is reduced in weight and cost and it is expected to reduce a physical burden and a financial burden for the users.

RELATED ART DOCUMENT

Patent Document

Japanese Unexamined Patent Application Publication No. 2012-50718

Problem to be Solved by the Invention

Improvement of walking assistance performances of the walking assistance device using the passive walking motion has been recently demanded.

DISCLOSURE OF THE PRESENT INVENTION

An object of the technology described herein is to provide a technology for further improving various performances of the walking assistance device using the passive walking motion such as walking assistance performances.

Means for Solving the Problem

A walking assistance device according to the present invention is to be put on a leg of a user to assist walking of the user, and the walking assistance device includes a waist wearing belt including a pad member to be put on a waist side portion of the user, the waist wearing belt to be put around a waist of the user, a thigh link portion having an elongated shape and to be arranged on a side of a thigh of the user, a lower leg link portion having an elongated shape and to be arranged on a side of a lower leg of the user, a lower leg wearing portion to be put on a lower leg of the user and mounted on the lower leg link portion, a waist joint portion configured to hold an upper end portion of the thigh link portion so that the thigh link portion swings in a front-rear direction of the user, the waist joint portion being mounted on the pad member of the waist wearing belt, and a knee joint portion configured to hold a lower end portion of the thigh link portion and an upper end portion of the lower leg link portion and configured to connect the thigh link portion and the lower leg link portion so that the thigh link portion and the lower leg link portion swing, respectively. The thigh link portion and the lower leg link portion have rigidity that is greater in the front-rear direction and an up-down direction than in a right-left direction so as to be elastically twisted around an axis along an elongated direction of the thigh link portion and the lower leg link portion. In the walking assistance device, provided with the above configurations, the thigh link portion and the lower leg link portion have rigidity that is greater in the front-rear direction and an up-down direction than in a right-left direction. Therefore, if a twisting force to twist about an axial line (rotary axis) along the elongated direction is applied to the link portions, the link portions are elastically deformed easily so as to be twisted. Therefore, a user who is wearing the walking assistance device can change his/her direction with twisting his/her waist in a relatively small space.

In the walking assistance device, each of the thigh link portion and the lower ling portion may include a pair of tubular portions and a plate-like connection portion. The pair of tubular portions may be arranged parallel to each other with having a distance therebetween and each of the tubular portions may have a space therein, and the connection portion may be provided between the tubular portions to connect the tubular portions. In the walking assistance device, each of the thigh link portion and the lower ling portion includes a pair of tubular portions and the plate-like connection portion. The pair of tubular portions is arranged parallel to each other with having a distance therebetween and each of the tubular portions has a space therein, and the connection portion is provided between the tubular portions to connect the tubular portions. Therefore, the walking assistance device is reduced in weight thereof.

In the walking assistance device, the thigh link portion and the lower leg link portion may be extendable in the elongated direction. The longitudinal lengths of the thigh link portion and the lower leg link portion are adjusted, and the size of the walking assistance device is adjusted according to the users' build.

In the walking assistance device, the waist joint portion may hold the upper end portion of the thigh link portion so as to be removed therefrom, and the knee joint portion may hold the lower end portion of the thigh link portion and the upper end portion of the lower leg link portion so as to be removed therefrom. With the above configurations of the waist joint portion and he knee joint portion, the thigh link portion is replaced with another one and the lower leg link portion is replaced with another one.

In the walking assistance device, the thigh link portion may be selected from a thigh link portion group including a plurality kinds of thigh link portions having different conditions such as various elongated lengths, and the lower leg link portion may be selected from a lower leg link portion group including a plurality kinds of lower leg link portions having different conditions such as various elongated lengths. In the walking assistance device, the thigh link portion and the lower leg link portion are selected from various kinds of link portions, respectively. Therefore, the lengths of the thigh link portion and the lower leg link portion are appropriately determined according to a user's request (such as a user's body size).

In the walking assistance device, the lower leg wearing portion may be selected from a lower leg wearing portion group including plurality kinds of lower link wearing portions having different conditions such as various circumferential lengths. In the walking assistance device, the lower leg wearing portion is selected from a lower leg wearing portion group including plurality kinds of lower link wearing portions having different conditions such as various circumferential lengths. Therefore, the circumferential length of the lower leg wearing portion is appropriately determined according to a user's request (such as a user's body size).

The walking assistance device may further include a weight that is detachably mounted on the thigh link portion and/or the lower leg link portion. With such a configuration of the walking assistance device, the swing patterns of the thigh link portion and the lower leg link portion are altered.

In the walking assistance device, the weight may be selected from a group of various kinds of weights having various weights. The weight is selected from a group of various kinds of weights. Therefore, the swing patterns of the thigh link portion and the lower leg link portion are altered according to a user's request.

In the walking assistance device, each of the thigh link portion and the lower leg link portion may include a pair of elongated plate-like processed components that are connected together to be opposed to each other. In the walking assistance device, each of the thigh link portion and the lower leg link portion has the above configuration. Therefore, the rigidity of the thigh link portion is maintained with the thigh link portion and the lower leg link portion being deformable in the twisting direction.

In the walking assistance device, the waist joint portion may include a waist shaft, a holder where one end of the waist shaft is fixed and that holds the upper end portion of the thigh link portion, a main body portion connected to the holder and configured to swing the thigh link portion around the waist shaft in a front-rear direction, a rotary plate supported on the waist shaft to be rotatable around the waist shaft and fixed to the main body portion, and amount plate fixed to the rotary plate to be rotatable with the rotary plate and mounted on the waist wearing belt via the pad member. The walking assistance device may further include a torque generator. The torque generator may include a compression spring, a determination portion being in contact with one end of the compression spring and configured to determine a position of the one end, a displacement portion being in contact with another end of the compression spring and configured to displace according to expansion and contraction of the compression spring, a cam follower connected to the displacement portion, and a cam portion having an outer surface configured to push the cam follower to compress the compression spring and having distances from the waist shaft so as to change along a circumferential direction, the cam portion included on a peripheral edge portion of the rotary plate. With the above configuration of the walking assistance device, the number of components included in the torque generator is decreased and the torque generator is decreased in size and thickness.

In the walking assistance device, each of the thigh link portion and the lower leg link portion may be configured to be elastically twisted around a shaft along the elongated direction within an angle range of from +70° to −70°. If the thigh link portion and the lower leg link portion are elastically twisted in the above range, the thigh link portion and the lower leg link portion are effectively twisted and the twisted link portions easily recover original shapes during the user's walking. Further, the thigh link portion and the lower leg link portion having the above properties do not restrict the walking motion of the user wearing the walking assistance device including turning around but correct the user's walking motion.

Advantageous Effect of the Invention

According to the technology disclosed herein, various performances of the walking assistance device using the passive walking motion such as walking assistance performances are improved.

MODES FOR CARRYING OUT THE INVENTION

First Embodiment

A walking assistance device1according to one embodiment of the present invention will be described with reference toFIGS. 1 to 11.FIG. 1is a side view of the walking assistance device1according to a first embodiment.FIG. 2is a (perspective) view of a waist wearing belt2included in the walking assistance device1.FIG. 3is a view of the walking assistance device1that a user U wears. The walking assistance device1of this embodiment is a passive walking type and mainly includes a waist wearing belt2, a thigh link portion3, a lower leg portion4, a lower leg wearing portion, a waist joint portion6, a knee joint portion7, a thigh contact portion8, and a torque generator9. The walking assistance device1of this embodiment is for a right leg and put on a right leg U1of a user U. The walking assistance device1for right leg is used for a user U who has an affected right leg U1and a normal left leg U2. In another embodiment, the walking assistance device1for right leg may be put on a right leg of a user U who has a normal right leg and an affected left leg. InFIG. 1, a right side is a front side, a left side is a rear side, and an upper side and a lower side are above and below, respectively. InFIG. 3, a front side on a sheet is frontward, a rear side on a sheet is rearward, and an upper side and a lower side are above and below, respectively.

The waist wearing belt2is used to fix a link mechanism portion of the walking assistance device1to the user U and is put around the user's waist U3to be put on the user U. The waist wearing belt2includes a main body21having a substantially flat arched shape and an adjuster22that adjusts a tightening degree of the waist wearing belt2. The main body21is fit to the rear side of the waist U3and right and left sides (hip side portions) of the waist U3. The adjuster22is provided to connect front ends of the right and left side portions of the main body21. The main body21includes a pad member21athat is made of resin closed-cell foam and has cushioning properties. The pad member21ais provided on an inner portion of the main body that is put on a right waist portion U31of the waist U3. A pad member21bhaving cushioning properties is provided on an inner portion of the main body that is put on a left waist portion U32of the waist U3. When the user U wears the waist wearing belt2, the pad member21ais in closely contact with the right waist portion U31and the pad member21bis in closely contact with the left waist portion U32. The right pad member21ais opposite the left pad member21b(left waist portion U32) with holding the waist U3(the pelvis) therebetween.

The main body21includes therein a flat core made of resin. Therefore, the main body21supports the pad members21a,21bfrom an inner side thereof. The main body21has flexibility and is deformable so that the front end portions thereof on the right and left sides are close to or away from each other. The main body21includes a receiver portion23on an outer side with respect to the right pad member21aand the receiver portion23has a pocket-like shape that is open downwardly. The receiver portion23receives therein an upper end portion of a mount plate60that is included in the waist joint portion6of the walking assistance device1. The mount plate60is rotatable (swings) with respect to a waist shaft61of the waist joint portion6as will be described later. The mount plate60has a hook-and-loop fastener portion60don at least an outer surface (a surface facing the front side on the sheet ofFIG. 1) in the surface of the upper end portion thereof. The receiver portion23has another hook-and-loop fastener portion (not illustrated) that is paired with the hook-and-loop fastener portion60dto be attached thereto and detached therefrom. The other hook-and-loop fastener portion is provided inside (on an inner side of) the receiver portion23. The upper end portion of the mount plate60is in the receiver portion23and the mount plate60is attached to the waist wearing belt2with adhesive force of the hook-and-loop fastener portions. The mount portion60whose upper end portion is in the receiver portion23is opposite the pad member21aof the waist wearing belt2. Namely, the pad member21aand the upper end portion of the mount plate60overlap each other.

The adjuster22includes a right belt portion22aand a left belt portion22b.The right belt portion22ais elongated on a right-side front end portion of the main body21and the left belt portion22bis elongated on a left-side front end portion of the main body21. The right belt portion22aand the left belt portion22bare attached to the respective front end portions of the main body21so as to adjust lengths thereof. The right belt portion22aand the left belt portion22bhave connector portions24(24a,24b), respectively, that are detachably connected to each other.

The waist wearing belt2including the mount plate60in the receiver portion23receives the motion (force) of the left leg (normal leg) U2without wearing the walking assistance device1using mainly the pad member21a.The waist wearing belt2transfers the received motion (force) to the waist joint portion6and the thigh link portion3via the mount plate60. The pad member21ais made of elastic material having cushioning properties and is elastically deformed to follow the surface shape of the waist U3(the waist side portion U31). The pad member21ahas effective strength and following capability (elasticity). Therefore, a gap is less likely to be generated between the pad member21aand the waist side portion U31and the force is surely transferred to the thigh link portion3and other portions of the walking assistance device1. Conditions of the pad member21asuch as a size, strength and elasticity (cushioning properties) are effectively determined with considering a size and a shape of the waist side portion U31of the user U.

FIG. 4is aside view of the thigh link portion3. The thigh link portion3is mainly arranged on a side (an outer side) of the thigh U11of the right leg U1(refer toFIG. 3), and has an elongated column-shaped (elongated) outer shape as a whole. The thigh link portion3is made of a metal plate (a metal plate member) such as an electro galvanized steel sheet (SECC) that is processed into a certain shape.FIG. 5is a cross-sectional view taken along line A-A′ inFIG. 4. As illustrated inFIG. 5, the thigh link portion3includes two elongated components that are fitted to (overlap) each other to face each other and form a tubular shape. One of the two components (processed components) constituting the thigh link portion3is a thigh inner member31that is provided adjacent to the thigh U11and another one of the two components is a thigh outer member32that is provided on an outer side with respect to the thigh inner member31to be opposite the thigh inner member31. In this embodiment, each of the metal plates (the metal plate member) used for the thigh inner member31and the thigh outer member32has a thickness of 0.4 mm and also has effective strength and flexibility so as to exert a flexible force when it is finally deformed to have a shape of the thigh link portion3. InFIG. 5, the thigh inner member31is on the right side and the thigh outer member32is on the left side.

The thigh inner member31mainly includes an inner main body31a,an inner projection portion (a first inner projection portion)31b,and an inner fitting portions31c,31c. The inner main body31ais a substantially elongated rectangular plate. The inner projection portion31bis in a middle portion of the inner main body31aand projected from the thigh U11side toward the thigh outer member32. The inner projection portion31bis in contact with the thigh outer member32. The inner fitting portions31c,31care processed to be recessed from the thigh U11side toward the thigh outer member32and form steps. The inner fitting portions31c,31care fitted to long-side ends of the thigh outer member32. The inner projection portion31bextends straight in the longitudinal direction of the thigh inner member31(the inner main body31a). If the thigh inner member31is seen from the thigh U11side, the inner projection portion31bhas a shape of an elongated recessed groove. The inner projection portion31bhas through holes31dat intervals in a line. The thigh inner member31is formed from the elongated rectangular metal plate member with a pressless forming method (registered trademark) that is one of drawing processing.

The thigh outer member32mainly includes an outer main body32a,an outer projection portion (a first outer projection portion)32b,and an outer fitting portions32c,32c. The outer main body32ais a substantially elongated rectangular plate. The outer projection portion32bis in a middle portion of the outer main body32aand projected from the outside toward the thigh inner member31(the thigh U11). The outer projection portion32bis in contact with the thigh inner member31. The outer fitting portions32c,32care formed by bending the long-side end portions of the outer main body32atoward the thigh inner member31. The outer fitting portions32c,32care overlapped with and fitted to the inner fitting portions31c,31c.The thigh outer member32has a length (in the longitudinal direction thereof) that is equal to a length (in the longitudinal direction) of the thigh inner member31. The outer projection portion32bextends straight in the longitudinal direction of the thigh outer member32(the outer main body32a). If the thigh outer member32is seen from the outside, the outer projection portion32bhas a shape of an elongated recessed groove. The outer projection portion32bhas through holes32dat intervals in a line similarly to the inner projection portion31b.The through holes32dformed in the outer projection portion32boverlap the through holes31dformed in the inner projection portion31b,respectively. They are used to fix the thigh contact portion8. Each through hole32dhas a size equal to that of each through hole31d.The thigh outer member32is formed from a rectangular metal plate member that is wider (greater short-side length) than the thigh inner member31with the pressless forming method (registered trademark).

As illustrated inFIG. 5, the outer projection portion32bof the thigh outer member32included in the thigh link portion3is in closely contact with the inner projection portion31bof the thigh inner member31. The outer fitting portions32c,32cof the thigh outer member32are fitted to the respective inner fitting portions31c,31cso as to push the thigh inner member31toward the outer main body32a.Accordingly, the thigh outer member32is fitted to hold the thigh inner member31. A contact portion of the inner projection portion31band the outer projection portion32bthat are in contact with each other and fitting portions of the respective inner fitting portions31c,31cand the respective outer fitting portions32c,32cthat are fitted together form spaces therebetween along the longitudinal side of the thigh link portion3. When the thigh inner member31and the thigh outer member32are fitted together, the thigh inner member31is slid along the long side from one end toward another end of the thigh outer member32and inserted into the spaces inside the thigh outer member32.

The thigh link portion3as a whole is constituted by the two elongated processed components (the thigh inner member31and the thigh outer member32) that are fitted together to form a tubular (columnar) shape having a space therein. The inner projection portion31band the outer projection portion32bare provided as reinforcing members that improve strength of the thigh link portion3. Therefore, the thigh link portion3has enough rigidity against the force applied in the longitudinal direction thereof (for example, a force acting on the thigh link portion3to pull it in the longitudinal direction, a force acting on the thigh link portion3to compress it in the longitudinal direction) in use of the walking assistance device1. Therefore, the thigh link portion3is less likely to be broken or bent. Even if a force is applied to the thigh link portion3so that two end portions in the longitudinal direction thereof are getting closer to each other in use of the walking assistance device1, the thigh link portion3having rigidity is less likely to be bent. The thigh link portion3has sufficient rigidity for the walking assistance device1in a direction of a torque acting on the thigh link portion3around the waist shaft61and in a direction of a torque acting on the thigh link portion3around the knee shaft71.

The thigh link portion3of this embodiment is slightly deformed to be twisted if the thigh link portion3receives a twisting force around a longitudinal shaft line (a rotary shaft) thereof. The thigh inner member31and the thigh outer member32constituting the thigh link portion3are formed of the processed metal plate members having flexibility and are not fixed to each other firmly. Therefore, the thigh link portion3is elastically deformed as a whole in the twisting direction when the thigh link portion3is twisted. For example, the inner fitting portion31cof the thigh inner member31and the outer fitting portion32cof the thigh outer member32are fitted together with overlapped but are not fixed to each other firmly.

The rigidity of the thigh link portion3and the elastic deformation degree of the thigh link portion3in the twisting direction are adjusted by altering various conditions such as a plate thickness or a kind of metal of the components31,32of the thigh link portion3, a size or a shape of the outer projection portion32bof the thigh outer member32and the inner projection portion31bof the thigh inner member31, a size of the inner space of the thigh link portion3, and a fitting force between the inner fitting portions31c,31cand the outer fitting portions32c,32c.For example, the components31,32made of stainless material having great strength instead of SECC increases strength of the thigh link portion3. If (a size of) the inner space of the thigh link portion3is increased, the strength of the thigh link portion3in an axial direction thereof is increased and the second moment of area is also increased. Accordingly, bending strength is increased. However, this increases the twisting strength. Therefore, the conditions are necessary to be set according to the user's leg strength.

One end portion (an upper end portion)3aof the thigh link portion3is connected to the waist joint portion6and another end portion (a lower end portion)3bis connected to the knee joint portion7, as will be described later.

The thigh link portion3has a length (in the longitudinal direction thereof) that is set as follows. In condition that the upper end portion3ais connected to the waist joint portion6and the lower end portion3bis connected to the knee joint portion7, when a center of the waist shaft61of the waist joint portion6is slightly above the greater trochanter of the user's waist side portion U31(for example, several centimeters above the greater trochanter or at the position of the user's hip joint), a center of the knee shaft71of the knee joint portion7is slightly above the user's knee joint. The center of the knee shaft71of the knee joint portion7may be set in any position within a range from the upper end to the lower end of the user's knee joint portion (that is, a range of the knee joint portion). In this embodiment, the length of the thigh link portion3is set to 300 mm.

The thigh link portion3includes a pair of tubular portions33,34and a connection portion35having a plate-like shape. The tubular portions33,34are parallel to each other with a distance therebetween and include spaces33a,34arespectively. The connection portion35is between the tubular portions33,34and connects the tubular portions33,34. The tubular portions33,34are constituted by the thigh inner member31and the thigh outer member32. The connection portion35is also constituted by the thigh inner member31and the thigh outer member32.

A lower leg link portion4is mainly arranged on a side (an outer side) of a lower leg U12of the right leg U1(seeFIG. 3). The lower leg link portion4has an outer appearance of an elongated columnar shape (an elongated shape) as a whole similarly to the thigh link portion3. The lower leg link portion4has a length in a longitudinal direction thereof, a width (a length in a short-side direction), and a thickness each of which is slightly smaller than that of the thigh link portion3. The lower leg link portion4is made of a metal plate (a metal plate member) such as an electro galvanized steel sheet (SECC) that is processed into a certain shape similarly to the thigh link portion3. Specifically, the lower leg link portion4is formed by fitting (overlapping) two elongated components together so as to be opposed to each other to form a tubular shape.

The lower leg link portion4of this embodiment is slightly deformed to be twisted if the lower leg link portion4receives a twisting force around a longitudinal shaft line (a rotary shaft) thereof.

One end portion (an upper end portion)4aof the lower leg link portion4is on the thigh link portion3side and is connected to the knee joint portion7as will be described later. Another end portion (a loser end portion)4bof the lower leg link portion4is on a side of the user's ankle. As illustrated inFIGS. 1 and 2, a protection cap10is fitted to the lower end portion4b.The protection cap10prevents the lower leg link portion4from bending.

The protection cap10is made of metal material such as aluminum or magnesium and the metal material is processed into a certain shape. The protection cap10has a fitting hole where the lower end portion4bof the lower leg link portion4is fitted. The lower end portion4bof the lower leg link portion4is fixed to the fitting hole with adhesive. The lower end portion4bis fixed to the fitting hole and the lower end portion4bof the lower leg link portion4is protected by the protection cap10.

The length of the lower leg link portion4(in the longitudinal direction thereof) is smaller than the length of the thigh link portion3(in the longitudinal direction thereof). The lower leg link portion4has a length so that a lower leg wearing portion5(which will be described later) mounted on the lower leg link portion4is put on a lower leg U12of the user U. In this embodiment, the length of the lower leg link portion4is 250 mm. In another embodiment, the length of the lower leg link portion4may be smaller. As illustrated inFIG. 3, in the walking assistance device1that is put on the user, the lower end portion4bof the lower leg link portion4is above the user's ankle. As illustrated inFIG. 3, the lower leg link portion4is on an inner side with respect to the thigh link portion3.

As illustrated inFIGS. 1 and 3, a lower leg wearing portion (shin cuff)5is put on the lower leg U12of the user's right leg U1and has a substantially U shape as a whole so as to hold the lower leg U12from the front and rear sides. The lower leg wearing portion5transfers (outputs) a motion of (a force from) the lower leg link portion4to the lower leg U12of the user U. The lower leg wearing portion5has a shape of a figure of eight that is curved with a plan view from an outer side (a right side) where the lower leg link portion4is fixed. A front portion of the leg wearing portion5is curved rearward and a rear portion thereof is curved frontward. The lower leg wearing portion5has through holes5afor decreasing a weight thereof and improving elasticity. The lower leg wearing portion5has a tapered shape from an upper portion toward a lower portion thereof. The lower leg wearing portion5has a gap between a front end portion and a rear end portion and the lower leg U12is put in or removed from the lower leg wearing portion5through the gap. The lower leg wearing portion5is formed by processing synthetic resin into a certain shape and has effective strength and elasticity. Therefore, the lower leg wearing portion5is tightly fit to the lower leg12with slightly being expanded. If the lower leg wearing portion5is too large for the lower leg U12or the lower leg wearing portion5is too flexible to be excessively expanded, the motion of the lower leg link portion4is not effectively transferred to the lower leg U12via the lower leg wearing portion5. Therefore, conditions of the lower leg wearing portion5such as a size, strength, elasticity are determined according to a size, a shape, and a position of the lower leg U12of the user U. The lower leg wearing portion5is detachably fixed to an inner side surface of the lower leg link portion4with a screw-shaped fixing member51. The screw-shaped fixing member51is inserted through through holes42d,41dformed in the lower leg link portion4to be fixed to the lower leg link portion4. The positions of the through holes42d,41din the lower leg link portion4may be altered to adjust the mount position of the lower leg wearing portion5in the height direction. A mounting angle at which the lower leg wearing portion5is mounted to the fixing member51may be altered in the front-rear direction to adjust inclination of the lower leg wearing portion5in the front-rear direction.

The waist joint portion6holds the upper end (the upper end portion3a) of the thigh link portion3and the thigh link portion3is supported by the waist joint portion6to swing in the front-rear direction of the user U. The waist joint portion6is mounted on the waist wearing belt2to be opposite the pad member21a.FIG. 6is an inner side view of the waist joint portion6.FIG. 7is a cross-sectional view taken along line C-C′ inFIG. 6. A cross-sectional configuration of the vicinity of the waist joint portion6taken along line C-C′ including two lines crossing at a center0of the waist shaft61inFIG. 6is illustrated inFIG. 7. As illustrated inFIGS. 6 and 7, the waist joint portion6includes the waist shaft61having a substantially cylindrical shape, a rotary plate62, a housing (a main body)63, a stopper64, a holder65, and a mount plate60. The rotary plate62is rotatably supported on the waist shaft61. One end of the waist shaft61is fixed to the housing63and the rotary plate62is arranged in the housing63. The stopper64is fixed to another end of the waist shaft61and stops the rotary plate62supported on the waist shaft61from dropping off therefrom. The holder65is formed integrally with the housing63and holds the upper end portion3aof the thigh link portion3to connect the waist joint portion6and the thigh link portion3. The mount plate60is fixed to the rotary plate62so as to be rotatable with the rotary plate62and mounted on the waist wearing belt2to be opposite the pad member21a.The components included in the waist joint portion6are made of metal material such as aluminum and magnesium and the metal material is processed into a certain shape with a known processing technology (such as means of cut machining). In other embodiments, the components of the waist joint portion6may be made of other material such as engineering plastic.

The waist shaft61has one end that is fixed to the housing63as described above. The housing (main body)63has a circular shallow bowl shape as a whole and the waist shaft61projects from a middle portion of an inner surface of the housing63. The waist shaft61includes a resin layer61bon a peripheral surface thereof to reduce friction against a peripheral surface of a shaft hole62bof the rotary plate62. As illustrated inFIG. 6, the rotary plate62has a substantially disk-like shape and made of metal material. The rotary plate62includes a disk-like shaped main body62a,a shaft through hole62b,and fixing through holes62c,62c.The main body62ahas the shaft through hole62bin a middle portion thereof and the waist shaft61is inserted through the shaft through hole62b.The disk-like main body62ahas at least a pair of fixing through holes62c,62cto be opposite each other with having the shaft hole62btherebetween. As illustrated inFIG. 6, five pairs of the fixing through holes62c(10in total) are formed in the main body62aof the rotary plate62. In this embodiment, the two adjacent fixing through holes62c,62cthat are along the periphery of the rotary plate62are formed so that an angle θx formed between a line connecting the center O and a center of one of the two adjacent fixing through holes62cand a line connecting the center O and a center of another one of the two adjacent fixing through holes62cis 15°. The fixing through holes62care used to fix the mount plate60to the rotary plate62with the screw-shaped fixing member (not illustrated).

The disk-like shaped stopper64is attached to the other end of the waist shaft61and the disk-like shaped stopper64has a diameter greater than that of the waist shaft61. The waist shaft61and the stopper64have screw holes61a,64ain central portions thereof, respectively, and screw-shaped fixing members (not illustrated) are inserted in the respective screw holes61a,64a.The screw-shaped fixing members (not illustrated) are inserted in the respective screw holes61a,64aand tightened so that the stopper64is fixed to the other end of the waist shaft61. The stopper64stops the rotary plate62that is supported on the waist shaft61from dropping off from the waist shaft61unnecessarily during usage of the walking assistance device1.

The mount plate60will be described. The upper end portion of the mount plate60is mounted on the waist wearing belt2, as described before. The lower end portion of the mount plate60is fixed to the rotary plate62that is rotatably supported on the waist shaft61. The mount plate60has a substantially rectangular shape as a whole and the lower end portion thereof has a shape following an arch-shaped peripheral edge of the housing63(arched shape). The mount plate60is made of plastic material or metal material. In this embodiment, the mount plate60is made of resin material such as acrylic, high-molecular-weight polyethylene, or polycarbonate. The mount plate60includes a main body60ahaving a plate-like shape, a through hole portion60b,and a fixing hole60c.The stopper64fixed to the waist shaft61can be visible through the through hole portion60b.The mount plate60is fixed to the rotary plate62using the fixing hole60c.

In fixing the mount plate60to the rotary plate62, the mount plate60is overlapped with the rotary plate62so that the fixing through hole60cof the mount plate60overlaps the fixing through hole62cof the rotary plate62. As is not illustrated inFIG. 7, the mount plate60has at least a pair of fixing through holes60c(two fixing through holes60c) that are opposite each other with having the through hole portion60btherebetween. In this embodiment, the mount plate60is overlapped with the rotary plate62so that the two fixing through holes60cof the mount plate60overlap respective fixing through holes62c1,62c1in pair among the fixing holes62cof the rotary plate62illustrated inFIG. 6.

A bolt-shaped fixing member (not illustrated) is inserted in the fixing through hole62c(62c1) and the fixing through hole60cthat are overlapped with each other. The rotary plate62has the fixing through holes62cand nut-shaped fixing members (not illustrated) are arranged in spaces62gin the respective fixing through holes62c.Therefore, after the nut-shaped fixing member is arranged in the space62g,the bolt-shaped fixing member is inserted to the fixing through hole60cof the mount plate60and the fixing through hole62cof the rotary plate62to be screwed into the nut-shaped fixing member. Accordingly, the mount plate60is fixed to the rotary plate62. The mount plate60is mounted on the waist shaft61so as to rotate (swing) in the front-rear direction similarly to the rotary plate62. The rotary plate62includes a cam portion62dthat constitutes a torque generator9as will be described later. The rotary plate62has a smoothing portion62fon an outer surface (opposite the housing63). The smoothing portion62fhas a ring shape surrounding the shaft hole62band is made of resin. The smoothing portion62freduces friction caused between the rotary plate62and the housing63and also reduces wearing of the rotary plate62.

The holder65is formed integrally with the lower end portion of the housing (main body)63. The holder65has a square tubular shape that is open downward as a whole. The holder65has an insertion hole65aat a lower end thereof where the upper end portion3aof the thigh link portion3is inserted. The upper end portion3aof the thigh link portion3is fixed to the insertion hole65aof the holder65with adhesive. Thus, the upper end portion3ais fixed to the insertion hole65aso that the holder65holds the thigh link portion3.

As described above, the waist joint portion6that is mounted on the waist wearing belt2holds the thigh link portion3so that the thigh link portion3rotates (swings) about the waist shaft61in the front-rear direction.

FIG. 8is a cross-sectional view of the knee joint portion7taken along line L-L′ inFIG. 1. The knee joint portion7connects the thigh link portion3and the lower leg link portion4so as to rotate (swing), respectively. The knee joint portion7includes a knee shaft71having a substantially columnar shape, a lower leg side knee joint portion72that holds the upper end portion4aof the lower leg link portion4, a thigh side knee joint portion73that holds the lower end portion3bof the thigh link portion3, and a screw-shaped fixing member74that fixes the knee shaft71to the thigh side knee joint portion73. The lower leg side knee joint portion72and the thigh side knee joint portion73overlap each other and rotate (swing) about the knee shaft71, respectively. The lower leg side knee joint portion72and the thigh side knee joint portion73of this embodiment are formed by processing metal material such as aluminum into certain shapes with a known processing technology (such as means of cut machining).

As illustrated inFIG. 8, the knee shaft71has an insertion through hole71aat a center thereof (on a shaft line P). A screw-shaped fixing member74is inserted through the insertion through hole71a.The knee shaft71has one end that is on the thigh side knee joint portion73side and another end having a diameter greater than that of the one end. A greater diameter portion71bthat is the other end prevents the lower leg side knee joint portion72that is supported on the knee shaft71from dropping off from the knee shaft71. The one end of the knee shaft71having a smaller diameter includes a resin layer71con a peripheral surface thereof to reduce occurrence of friction.

The lower leg side knee joint portion72includes a main body72aand a holder portion72b.The main body72amainly overlaps the thigh side knee joint portion73and has a substantially disk-like shape. The holder portion72bis continuous from a lower end of the main body72aand holds the upper end portion4aof the lower leg link portion4. The main body72ahas a shaft through hole72dthrough which the knee shaft71is inserted. An inner diameter of the shaft through hole72dis greater on an opposite side than on the thigh side knee joint portion73side. The greater diameter portion71bof the knee shaft71is arranged in a greater inner diameter portion of the through hole72d.The portion of the knee shaft71having a smaller diameter is arranged in a smaller inner diameter portion of the shaft through hole72dthat is on the thigh side knee joint portion73side.

The holder portion72bhas a square tubular shape that is open downward as a whole and is formed integrally with the main body72a.The holder portion72bhas an insertion hole72con a lower end thereof and the upper end portion4aof the lower leg link portion4is inserted in the insertion hole72c.The upper end portion4aof the lower leg link portion4is fixed to the insertion hole72cof the holder portion72bwith adhesive. Thus, the upper end portion4ais fixed to the insertion hole72cso that the holder portion72bof the lower leg side knee joint portion72holds the lower leg link portion4.

The thigh side knee joint portion73includes a main body73aand a holder portion73b.The main body73amainly overlaps the lower leg side knee joint portion72and has a substantially disk-like shape. The holder portion73bis continuous from an upper end of the main body73aand holds the lower end portion3bof the thigh link portion3. The main body73ahas a shaft hole73dhaving a bottom where a distal end portion of the screw-shaped knee shaft71is inserted and screwed into. The shaft hole73dis on the shaft line P of the knee shaft71.

The holder portion73bhas a square tubular shape that is open upward as a whole and is formed integrally with the main body73a.The holder portion73bhas an insertion hole73con an upper end thereof and the lower end portion3bof the thigh link portion3is inserted in the insertion hole73c.The lower end portion3bof the thigh link portion3is fixed to the insertion hole73cof the holder portion73bwith adhesive. Thus, the lower end portion3bis fixed to the insertion hole73cso that the holder portion73bof the thigh side knee joint portion73holds the thigh link portion3.

As described before, the knee joint portion7connects the thigh link portion3and the lower leg link portion4via the knee shaft71(around the knee shaft71) so as to rotate (swing) respectively. The knee joint portion7may include a resin smoothing portion on a portion thereof where the lower leg side knee joint portion72and the thigh side knee joint portion73are in contact with each other to reduce occurrence of friction therebetween and wearing.

FIG. 9is an enlarged rear view of the thigh contact portion8. As illustrated inFIG. 3, the thigh contact portion8is put on a thigh U11of a user's right leg U1to support the thigh U11. The thigh contact portion8is smaller in size than the lower leg wearing portion5and has a flat shape extending in the front-rear direction. The thigh contact portion8is curved to follow a side surface shape of the thigh U11. The thigh contact portion8is formed by processing synthetic resin into a certain shape similarly to the lower leg wearing portion5. The thigh contact portion8includes contact portions81and a fixing portion83that has a cylindrical shape. Each of the contact portions81has a curved flat shape and is put on the thigh U11. The fixing portion83projects from the contact portions81and is fixed to the main body3cof the thigh link portion3. Each contact portion81has a through hole82for reducing a weight of the thigh contact portion8.

The thigh contact portion8is fixed to the thigh link portion3via the fixing portion83such that the contact portions81are put on the thigh U11and arranged between the thigh link portion3and the thigh U11. The thigh link portion3has the through holes32d,31dand the screw-shaped fixing member84(seeFIG. 1) is inserted through the through holes32d,31dand screwed into the fixing portion83of the thigh contact portion8. Accordingly, the thigh contact portion8is fixed in a certain position of the thigh link portion3. In this embodiment, the thigh contact portion8is mounted on the thigh link portion3so as to be put on a portion of the thigh U11that is above a middle portion thereof with respect to the height dimension (the up-down direction). The thigh contact portion8is put on a substantially middle portion of the thigh U11with respect to the front-rear direction. An angle between the contact portion81of the thigh contact portion8and the thigh link portion is adjusted by altering a fixing angle between the fixing portion83and the thigh link portion. In another embodiment, the thigh contact portion8may be mounted on the thigh link portion3to be put on a portion of the thigh U11below the middle portion thereof, or the thigh contact portion8may be put on an outermost portion of the thigh U11. The thigh contact portion8may be mounted on any portion of the thigh link portion3as long as the thigh contact portion8is at least put on the thigh U11.

The user U who wears the walking assistance device1including the thigh contact portion8stably and easily keeps a standing posture when the user U stands up. The user U stably keeps a balanced posture (in the right-left direction) in one leg standing with the right leg U1wearing the walking assistance device1, because the right leg U1is supported by the three points including the waist wearing belt2, the lower leg wearing portion5, and the thigh contact portion8. The balanced posture of the right leg U1in the right-left direction is stably kept when the right leg U1functions as a support leg (a landing leg) during the user's walking with the walking assistance device1. While the user U is walking, a force is likely to be transferred from the walking assistance device1to the right leg U1via the lower leg wearing portion5and the thigh contact portion8.

The torque generator9generates a joint torque around the waist shaft61using a cam-spring mechanism. As illustrated inFIGS. 6 and 7, the torque generator9mainly includes a compression spring91, a determination portion92, a displacement portion93, a cam follower (a roller follower)94, a cam portion62d,a tubular housing portion95, and a cam follower arrangement portion96. The determination portion92has a columnar shape and is in contact with one end of the compression spring91to determine a position of the one end. The displacement portion93is in contact with another end of the compression spring91and displaced by the compression spring91that expands and contracts. The cam follower94is connected to the displacement portion93. The cam portion62dhas an outer peripheral surface62ethat pushes the cam follower94so that the compression spring91is compressed. A distance from the waist shaft61to the outer peripheral surface62evaries along the peripheral direction. The cam portion62dis included in a part of a peripheral edge of the rotary plate62. The determination portion92, the compression spring91, and the displacement portion93are arranged in the tubular housing portion95. The cam follower arrangement portion96is connected to the tubular housing portion95. The cam follower94moves in the direction in which the compression spring91expands and contracts and the cam follower94is arranged in the cam follower arrangement portion96.

The compression spring91is a coiled spring having predetermined spring constant (a compression coil spring) and arranged in the tubular housing portion95. The columnar determination portion92that is made of metal is arranged at one end of the compression spring91in the tubular housing portion95. The determination portion92is arranged in the tubular housing portion95so as to be in contact with the one end of the compression spring91. The determination portion92has a spirally grooved screw outer surface92a.The tubular housing portion95has a spirally grooved screw inner surface95e.The screw outer surface92aand the screw inner surface95eare screwed together so that the determination portion92is fixed within the tubular housing portion95. The determination portion92has a straight slot groove (not illustrated) on an end surface thereof. A tool such as straight slot screwdriver is inserted in the groove to rotate the determination portion92. Accordingly, the determination portion92is moved up or down within the tubular housing portion95to adjust the position of the end of the compression spring91(namely, a spring compression amount of the compression spring91). A cover97is detachably put on one end portion (a distal end portion) of the tubular housing portion95. The cover97covers an opening95bat the distal end portion of the tubular housing portion95and has a screw outer surface that is fitted to the spirally grooved screw inner surface95e.In adjusting the position of the determination portion92(namely, the position of the end of the compression spring91), the cover97is removed from the tubular housing portion95. After the adjustment, the cover97is attached to the tubular housing portion95to close the opening95b.In the torque generator9included in the walking assistance device1, the generated torque is necessary to be adjusted frequently. For example, a torque to be generated is necessary to be adjusted finely according to a user's condition (such as a functional recovery degree or a fatigue degree of the affected leg) or a place of walking (such as a flat ground or sloped ground). Therefore, as is described in this embodiment, the position of the determination portion92that determines the compression amount of the compression spring91is necessary to be adjusted with a configuration described above.

The displacement portion93is arranged on another end portion side (a basal end side) of the tubular housing portion95and is in contact with another end of the compression spring91. The displacement portion93and the determination portion92hold the compression spring91therebetween. The displacement portion93is displaced in the expansion-contraction direction (along the axis of the tubular housing portion95) within the tubular housing portion95. The cam follower94having a roller portion94athat is pushed against the outer surface62eof the cam portion62dis mounted on the displacement portion93. The roller portion94ais rotatably mounted on a shaft portion94bthat is fixed to the displacement portion93. As the position of the roller portion94ais pushed upward due to the shape of the outer surface62eof the cam portion62d,the cam follower94and the displacement portion93are also lifted up to compress the compression spring91. As the position of the roller portion94ais lowered due to the shape of the outer surface62eof the cam portion62d,the cam follower94and the displacement portion93are also pushed down according to the expansion of the compression spring91. The tubular housing portion95includes the cam follower arrangement portion96at a basal end portion thereof. The roller portion94aof the cam follower94is arranged in the cam follower arrangement portion96. The roller portion94aof the cam follower94is arranged in the cam follower arrangement portion96so as to be displaced (moves up and down) in the shaft direction of the tubular housing portion95(the expansion and contraction direction of the compression spring91).

The rotary plate62integrally includes the cam portion62dthat is made of metal material similar to the rotary plate62. The rotary plate62has a substantially disk-like shape as described before and has an arched peripheral edge. The rotary plate62includes the outer surface (cam surface)62eof the cam portion62dat the arched peripheral edge thereof. As illustrated inFIG. 6, the cam portion62dhas a substantially semicircular shape. A distance from the center O of the waist shaft61to the outer surface62eincreases gradually from the front side toward the rear side along the periphery of the cam portion62d.In this embodiment, as illustrated inFIG. 6, the rotary plate62is supported on the waist shaft61so that the cam portion62dis located on the front oblique lower side. For example, as illustrated inFIG. 6, the cam portion62dhas a frontward radius r1and a rearward radius r2that is greater than the radius r1. As the radius of the cam portion62dis greater, the spring compression amount of the compression spring91is increased. As a result, a torque generated around the waist shaft61is also increased. The cam portion62dis included in the rotary plate62that is rotatably supported on the waist shaft61and the rotary plate62is fixed on the mount plate60as described before. The cam portion62dis fixed on the mount plate60in a predetermined mount position (at a predetermined mount angle).

The mount position of the cam portion62dis altered by adjusting the mount angle at which the rotary plate62is mounted on the mount plate60. Specifically, one of the pairs of fixing through holes62c,62c(five pairs in this embodiment) formed in the rotary plate62is selected to be fitted to the respective fixing through holes60c,60cof the mount plate60. The rotary plate62is fixed to the mount plate60using a predetermined fixing members through the selected fixing through holes62c,62cand the fixing through holes60cof the mount plate60so that the mount angle of the cam portion62dis altered. As the mount angle of the cam portion62dis altered, the relative positional relationship between the roller portion94aof the cam follower94and the outer surface62eof the cam portion62dis altered. The roller portion94aof the cam follower94is configured to move in the front-rear direction along the outer surface62eof the cam portion62daccording to the movement of the thigh link portion3that is rotated (swings) around the waist shaft61in the front-rear direction.

As illustrated inFIG. 6, the cam portion62dhas a front end portion62d1and a rear end portion62d2that are projections. As described before, the distance from the center O of the waist shaft61to the outer surface62eincreases gradually from the front side toward the rear side in a range of the outer surface62eof the cam portion62dbetween the front end portion62d1and the rear end portion62d2. The distance from the center O to the front end portion62d1and the distance from the center O to the rear end portion62d2are greater than the distances at other portions of the outer surface62e.Accordingly, the roller portion94aof the cam follower94does not climb over the front end portion62d1and the rear end portion62d2.

The torque generated by the torque generator9acts on the thigh link portion3to move the thigh link portion3frontward. The walking assistance device1of this embodiment including the torque generator9easily and effectively moves the thigh link portion3and the lower leg link portion4frontward and also the user U easily bends his/her knee joint. As a result, the user U is less likely to stumble during walking.

In the walking assistance device1of this embodiment, the upper end portion3aof the thigh link portion3is connected to the waist joint portion6having the waist shaft61, and the lower end portion3bof the thigh link portion3is connected to the knee joint portion7having the knee shaft71. The upper end portion4aof the lower leg link portion4is connected to the knee joint portion7having the knee shaft71. Thus, the walking assistance device1of this embodiment is a system having two link portions including the thigh ling portion3and the lower leg link portion4. The walking assistance device1is operated based on the passive walking and each of the waist shaft61of the waist joint portion6and the knee shaft71of the knee joint portion7is a single axis (a pitch axis).

A usage of the walking assistance device1will be described. First, an example of a method of wearing the walking assistance device1will be described. As illustrated inFIG. 3, the user U wears the waist wearing belt2of the walking assistance device1on his/her waist U3so that the one pad member21ais put on the right waist portion U31and the other pad member21bis put on the left waist portion U32. The waist wearing belt2is put around the waist U3of the user U. The tightening degree of the waist wearing belt2is adjusted so that the pad members21a,21bare closely fit on the respective waist side portions U31, U32. The tightening degree of the waist wearing belt2is adjusted by altering the lengths of the respective right belt portion22aand the left belt portion22bof the adjuster22. The user U may wear the waist wearing belt2with sitting on a chair or standing.

The waist wearing belt2is preferably put on slightly above the greater trochanter of the user's pelvis. As described before, the waist wearing belt2and the waist joint portion6are fixed to each other so as to be detachable from each other with using the hook-and-loop fastener. Therefore, the position of the waist shaft61is adjusted to a desired position by adjusting the mount position of the mount plate60of the waist joint portion6with respect to the waist wearing belt2(the receiver portion23). For example, it may be difficult for a user U who is extremely bent over to previously determine the mount position of the waist joint portion6with respect to the waist wearing belt2. In such a case, in the walking assistance device1of this embodiment, the waist joint portion6is detachable from waist wearing belt2. Therefore, the position of the waist shaft61is adjusted properly. As described before, the user U wears the walking assistance device1so that the waist shaft61is slightly above the position of the greater trochanter. The present inventor confirms that, with the above wearing method, the force is likely to be transferred to the right leg U1and the right leg U1is moved with more natural walking motion.

Next, the user U bends down slightly and inserts his/her ankle portion into the lower leg wearing portion5. Then, the user U pushes himself/herself up with his/her lower leg U12in the lower leg wearing portion5and holds himself/herself in a standing position. Then, the lower leg wearing portion5is moved upward and the inner surface of the lower leg wearing portion5is fit on the front and rear sides of the user's lower leg U12. Accordingly, the lower leg wearing portion5is put on the lower leg U12. Thus, the walking assistance device1is put on a user. The thigh contact portion8is automatically put on a predetermined position of the user's thigh U11after the wearing of the waist wearing belt2and the lower leg wearing portion5is completed. Thus, the wearing of the walking assistance device1is very easy and may be completed in a few seconds. In one of other wearing methods, the waist wearing belt2may be previously separated from other parts of the walking assistance device1. Thereafter, the separated waist wearing belt2and the other parts may be separately put on the user U and they may be fixed to each other with the hook-and-loop fastener.

When the user U wearing the walking assistance device1stands up on a flat ground X, the thigh link portion3and the lower leg link portion4are substantially straight in the vertical direction. The user U wearing the walking assistance device1of this embodiment easily and effectively keeps a balanced (in the right-left direction) one-leg standing posture with the affected right leg U1because the right leg U1is supported at the three points including the waist wearing belt2, the lower leg wearing portion5, and the thigh contact portion8. Accordingly, the user U stands up in a stable condition. In the walking assistance device1of this embodiment, the thigh link portion3includes the thigh contact portion8that supports the thigh U11from outside, as described before. The thigh contact portion8improves the stability of the right leg U1and provides the effects of support at the three points. Accordingly, the balanced one-leg standing posture with the right leg U1wearing the walking assistance device1is effectively kept and the user U stands in a stable condition. The present inventor confirms that the user's one-leg standing posture with the right leg U1wearing the walking assistance device without having the thigh contact portion8is unstable. However, in another embodiment, the walking assistance device1may be used with the thigh contact portion8being detached from the thigh link portion3, if necessary.

The tubular housing portion95of the torque generator9is continuous from the housing63of the waist joint portion6and extends toward the front oblique lower direction. Therefore, when the user U who is in the standing posture sits on a chair, the tubular housing portion95is less likely to be in contact with the chair. If the user U swings his/her arms in walking, the arms are less likely to be in contact with the tubular housing portion95.

Next, the walking motion of the user U wearing the walking assistance device1will be described. In human's walking (of the user U), one of the legs functions as a support leg landing on the ground and the other one of the legs functions as a free leg that is away from the ground. Such a motion is repeated alternately for the right leg U1and the left leg U2.FIG. 10is a schematic view illustrating the walking of the user U wearing the walking assistance device1. InFIG. 10, the left leg (the normal leg) U2lands on the ground X as the support leg, and the right leg (the affected leg) U1wearing the walking assistance device1is away from the ground X as the free leg. The walking assistance device1of this embodiment is operated based on the passive walking and it is considered that the user's left leg U2is connected to the walking assistance device1that is put on the right leg U1via the waist U3(pelvis). Namely, the pad member21aof the waist wearing belt2is configured to transfer the motion (the force) of the left leg (the normal leg) U2to the thigh link portion3and the lower leg link portion4via the mount plate60(the waist joint portion6) mounted opposite the pad member21a.As a result, the walking assistance device1put on the right leg U1naturally operates the leg motion to repeat alternately the motion of the free leg and the motion of the support leg according to the motion of the left leg (the normal leg) U2. Namely, the motion of the left leg U2that is a normal leg is transferred to the walking assistance device1put on the right leg U1so that the leg motion of the right leg U1during the walking motion is assisted by the walking assistance device1.

The walking assistance device1of this embodiment includes the torque generator9using the cam-spring mechanism as described before. Therefore, when the right leg U1functions as a free leg, the starting of the motion of the right leg U1is accelerated by the torque generated by the torque generator9. In this motion, elastic energy accumulated in the compression spring91is used. When the right leg U1functions as the support leg, the elastic energy is accumulated in the compression spring91in a last half of the support leg phase. The right leg U1is less likely to be tilted frontward. As a result, the left leg U2that functions as the free leg receives less shock in landing on the ground X.

At the initial timing of the starting of the motion of the right leg U1, it is necessary that the knee joint is bent to obviate the contact with the ground X so that the user may not stumble. The lower leg wearing portion5is mounted on the lower leg link portion4with being tilted rearward with respect to the longitudinal direction of the lower leg link portion4. Therefore, in walking, the knee joint portion7of the walking assistance device1is bent prior to the bending of the knee joint of the right leg U1. The present inventor confirms that the walking assistance device1assists the leg motion of the right leg U1and transfers the force (the torque) to the right leg U1effectively and the knee joint of the right leg U1is easily and smoothly bent as a result of such a configuration. It is also confirmed that the user U strongly feels that the leg is lifted upward (the knee joint is greatly bent). The lower leg wearing portion5may be tilted rearward with respect to the longitudinal direction of the lower leg link portion4at an angle ranging from 15° to 30°. The angle is not limited thereto.

In the walking assistance device1of this embodiment, a torque generation range of the torque generated by the torque generator9may be altered.FIG. 11is a graph illustrating torque properties of the torque generated by the torque generator9. A lateral axis (a cam follower angle θ1) of the graph inFIG. 11represents an angle θ1(°) formed between a center line M of the cam portion62dpassing through the center O of the waist shaft61and a line C′ passing through the center of the cam follower94and the center O of the waist shaft61(seeFIG. 6). A vertical axis of the graph represents a torque (Nm) generated around the waist shaft61.

When the upper body (the waist U3) stands upright during walking, the mount plate60mounted on the waist wearing belt2put on the waist U3is straight in the substantially vertical direction G. In such a condition, the cam follower94is tilted frontward at 20° with respect to the vertical direction G. Further, in this condition, if the cam portion62(the rotary plate62) is arranged so that the cam follower94is located at an angle of −20° rearward from the center line M of the cam portion62dand the thigh link portion3is moved in a range from the rearward −20° (absolute angle) to frontward 20° with respect to the vertical direction, the cam follower94is moved in a range from −40° to 0°. The torque corresponding to the range of the angle θ1is generated.

If the cam portion62(the rotary plate62) is arranged so that the cam follower94is located at an angle of −35° rearward from the center line M of the cam portion62dand the thigh link portion3is moved in a range from the rearward −20° (absolute angle) to frontward 20° with respect to the vertical direction, the cam follower94is moved in a range from −55° to −15°. The torque corresponding to the range of the angle θ1is generated and the range of the generated torque is higher than the torque range of the above case. The movement range of the cam follower94with respect to the outer surface62eis altered to alter the range of the torque generated by the torque generator9. Therefore, the user U may alter the movement range of the cam follower94according to the environment to adjust the range of the torque generated by the torque generator9.

In the walking assistance device1of this embodiment, the position of the determination portion92within the tubular housing portion95is altered to alter the spring compression amount of the compression spring91. Namely, the spring compression amount of the compression spring91is easily adjusted by altering the position of the determination portion92, and eventually the torque generated by the torque generator9is adjusted by altering the position of the determination portion92.

The walking assistance device1of this embodiment guides a user U a correct walking motion. The walking assistance device1of this embodiment is operated based on the passive walking principle that is closest motion of the humans' walking motion. When the user who has one affected leg (the right leg U1), as is in this embodiment, tries to walk correctly, it has been known that the right leg U1that is an affected leg moves from the rear side to the front side around himself/herself outwardly in an arc. However, if the user U wears the walking assistance device1of this embodiment, the user's affected leg (the right leg U1) is less likely to move around himself/herself outwardly and is guided to move in the front-rear direction.

Advantageous Effects

In the walking assistance of this embodiment, the thigh link portion3is formed of a pair of components (the thigh inner member31and the thigh outer member32) that are made of metal plate members processed into certain shapes. The thigh link portion3is constituted by the pair of components that are connected to each other in a tubular shape. Such a thigh link portion3is lighter than a thigh link portion made of metal and formed into a bar-like shape. Therefore, the user's load is greatly reduced. In the walking assistance device1of this embodiment, the lower leg link portion4has a configuration similar to that of the thigh link portion3. Therefore, the lower leg link portion4is lighter than a lower leg link portion made of a metal bar-shaped member and the user's load is greatly reduced. Thus, the thigh link portion3and the lower leg link portion4are reduced in weight and it is convenient to carry the walking assistance device1of this embodiment.

In the walking assistance device1of this embodiment, the inner projection portion31band the outer projection portion32bincluded in the thigh link portion3function as a reinforcing member that improves strength of the thigh link portion3, as described before. Therefore, such a thigh link portion3is configured to reduce a thickness thereof and provide sufficient strength to the walking assistance device1. In the walking assistance device1of this embodiment, the lower leg link portion4has a configuration similar to that of the thigh link portion3. Therefore, the lower leg link portion4is configured to reduce a thickness thereof and provide sufficient strength to the walking assistance device1due to the similar reasons.

The walking assistance device1of this embodiment includes the thigh link portion3and the lower leg link portion4having the above configurations. Therefore, the user U who is wearing the walking assistance device1changes his/her posture in the front-rear direction with rotating the waist U3. For example, if the user U who is wearing the walking assistance device1rotates (twists) his/her body (waist U3) to move a left shoulder rearward and move a right shoulder frontward (in a counterclockwise direction), a twisting force is applied to the thigh link portion3put on the side of the thigh U11of the right leg U1and the lower leg link portion4put on the side of the lower leg U12of the right leg U1. The thigh link portion3and the lower leg link portion4of this embodiment are elastically deformable in a twisting direction to some degree. Therefore, the thigh link portion3and the lower leg link portion4are less likely to hinder the user's motion of rotating (twisting) his/her body (waist U3). Therefore, the user U can move the right leg U1wearing the walking assistance device1according to the motion of rotating the body (waist U3). The user U who is wearing the walking assistance device1can move with rotating or twisting the body in a small space (for example, a kitchen aisle or a restroom stall). The user U1who is wearing the walking assistance device1can rotate his/her body in an opposite direction from the above (namely, in a clockwise direction).

The walking assistance device1of this embodiment effectively guides the user U to operate the correct walking motion. The walking assistance device1of this embodiment is operated based on the passive walking principle that is closest to the human's walking motion, as described before. Further, the walking assistance device1of this embodiment includes the thigh link portion3and the lower leg link portion4that are elastically deformable in the twisting direction, as described before. Therefore, for example, if the user's affected right leg U1wearing the walking assistance device1would move from the rear side to the front side around himself/herself outwardly in an arc, such a motion is corrected (restricted) to the correct walking motion based on the passive walking due to the elastic force of the thigh link portion3and the lower leg link portion4. Accordingly, the walking assistance device1effectively guides the user U to perform the correct walking motion.

In the walking assistance device1of this embodiment, the cam portion62dincluded in the torque generator9is supported on the waist shaft61of the waist joint portion6so as to rotate (swing) about the waist shaft61in the front-rear direction, and the cam portion62dis included in the rotary plate62that is fixed to the mount plate60. Thus, the cam portion62dis not provided as a single separate component but formed integrally with a component (the rotary plate62) that connects the waist joint portion6and the mount plate60so that the waist joint portion6and the mount plate60rotate (swing), respectively. The thigh link portion3is connected to the waist joint portion6and the mount plate60is mounted on the waist wearing belt2. Accordingly, the number of components included in the torque generator9is reduced and the torque generator9is reduced in size and thickness.

In the walking assistance device1of this embodiment, the cam portion62dincluded in the torque generator9is made of metal and therefore, the roller portion94aof the cam follower94is less likely to be pressed into the cam portion62d.Therefore, the torque generated by the torque generator9is less likely to be reduced due to the cam portion62dcompared to a cam portion made of resin. The cam portion62dmade of metal is less likely to be worn.

In the walking assistance device1of this embodiment, the mount angle at which the cam portion62dincluded in the torque generator9is mounted with respect to the cam follower94is adjusted by changing the mount angle at which the rotary plate62is mounted on the mount plate60. As described before, in this embodiment, the rotary plate62has five pairs of fixing through holes62c,62cand each of the pairs is shifted by 15° in the peripheral direction of the rotary plate62. Therefore, in this embodiment, the mount angle of the cam portion62dwith respect to the cam follower94is adjusted by every 15°.

In the walking assistance device1of this embodiment, the lower leg side knee joint portion72and the thigh side knee joint portion73included in the knee joint portion7rotate 360 degrees around the knee shaft71when the walking assistance device1is not put on a user. Therefore, the lower leg link portion4and the thigh link portion3can be arranged to overlap each other. Thus, the walking assistance device1of this embodiment can be folded into a small size.

In the walking assistance device1of this embodiment, the waist wearing belt2is put on the user U to be put around the user's waist U3. The pad members21a,21bof the waist wearing belt2hold the user's waist from the right and left sides. The mount plate60included in the waist joint portion6is mounted in the receiver portion23of the waist wearing belt2using the hook-and-loop fastener. In the walking assistance device1having such a configuration, the thigh link portion3and the lower leg link portion4of the walking assistance device1is supported only by the waist wearing belt2. In another embodiment, a shoulder belt may be connected to the waist wearing belt2at two ends thereof and the shoulder belt may be put on a user's shoulder to support the waist wearing belt2.

Twisting properties of the thigh link portion3and the lower leg link portion4included in the walking assistance device1of this embodiment will be described. Each of the thigh link portion3and the lower leg link portion4is formed of two thin elongated processed metal plates. The two thin elongated processed metal plates are connected to each other to have a space therein and form a tubular (columnar)) shape (hereinafter, referred to as a hollow leg member).

When a person (the user U) stands with facing frontward, he/she can twists his/her lower leg in a range of approximately 40° to 50° outwardly and inwardly. A human's lower leg normally generates a twisting torque of approximately 1 Nm. The thigh link portion3and the lower leg link portion4of the walking assistance device1are elastically deformed to be twisted around the shaft (the rotational shaft) along the longitudinal direction thereof in the right and left directions within the twisting range of a human (the user U).

FIG. 12is a graph illustrating a relationship between a twisting angle θ (°) of the hollow leg member and a generated twisting torque τ (Nm). InFIG. 12, a lateral axis of the graph represents the twisting angle θ (°) and a vertical axis thereof represents the twisting torque τ (Nm). A line X1illustrated inFIG. 12represents a relationship between the twisting angle θ (°) of the hollow leg member and the generated twisting torque τ (Nm). A component used for the thigh link portion3(40 cm length) is used as the hollow leg member.

The hollow leg member is elastically deformable within the range of the twisting angle θ (°) ranging from 0° to 70° (0≦θ≦70). If the twisting angle exceeds the range, the hollow leg member will be plastically deformed. As illustrated inFIG. 12, the possible twisting angle θ (°) of the hollow leg member is 0≦θ≦50 according to the range of the torque that is normally generated by a human (≦1 Nm). Considering variations, the elastically deformable range, that is, the twisting angle θ (°) at which the hollow leg member can be elastically twisted around the shaft along the longitudinal direction is 0≦θ≦70. Therefore, the hollow leg member can be used with keeping the elastically deformable state within this range.

InFIG. 12, a graph X2represents relation between a twisting angle θ (°) of a solid leg member formed by machining aluminum material and a generated twisting torque τ (Nm) as a comparative example. As illustrated inFIG. 12, the twisting angle θ (°) at which the solid leg member can be twisted is approximately zero according to the range of the torque that is normally generated by a human (≦1 Nm). The solid leg member having such a range of the twisting angle θ (°) may not provide any advantageous effects caused by the twisting.

The thigh link portion3and the lower leg link portion4of the walking assistance device1are effectively twisted and recovered from the twisted state (have torsion stiffness) while a person (the user U) is walking (including change of direction). Therefore, the walking motion of the user U who wears the walking assistance device1is not restricted but may be corrected.

If the thigh link portion and the lower leg link portion have the torsion stiffness that is too high, as is in the comparative example (the solid leg member), the leg (the lower leg) is not effectively twisted with the torque of 1 Nm and the twisting motion is restricted. If the thigh link portion and the lower leg link portion have the torsion stiffness that is too low, the torque sufficient to recover the person's leg (the user's leg) to an original position is not generated and the person's leg is kept with twisted.

Accordingly, it is effective that the thigh link portion3and the lower leg link portion4are elastically twisted around the shaft along the longitudinal direction thereof within the range of +70° to −70°. “+” represents the outward twisting motion of the leg (the lower leg) and “−” represents the inward twisting motion thereof.

Second Embodiment

The second embodiment of the present invention will be described with reference toFIG. 13.FIG. 13is an enlarged rear view of a thigh contact portion8A included in a walking assistance device of the second embodiment. In the walking assistance device of this embodiment, the thigh contact portion8A that is contacted with the thigh U11of the user U is made of elastic material. The thigh contact portion8A includes the thigh contact portion8of the first embodiment and an elastic member that covers a surface of the thigh contact portion8. The elastic member used for the thigh contact portion8A is preferably an elastic member made of resin foam having delayed elasticity that easily follows the surface shape of the thigh U11. For example, elastic material used for TEMPUR (registered trademark) may be processed to have a certain shape to be used as the elastic member of this embodiment. With such a thigh contact portion8A including the elastic member, the force is less likely to be concentrated on the thigh U11while the user U is wearing the walking assistance device. Therefore, the user U is less likely to feel pain caused by the contact even if the thigh contact portion8A is in contact with the thigh U11. In another embodiment, a thigh contact portion may be formed to be slightly smaller than the thigh contact portion8of the first embodiment and the above elastic member may be attached to a core member to be fixed to the thigh link portion. The walking assistance device of this embodiment has the configuration same as that of the first embodiment other than the thigh contact portion8A.

Third Embodiment

Next, a third embodiment of the present invention will be described with reference toFIGS. 14 and 15.FIG. 14is a front view of a lower leg wearing portion5A used in a walking assistance device of the third embodiment.FIG. 15is a top view of the lower leg wearing portion5A used in a walking assistance device of the third embodiment. The walking assistance device of this embodiment has the configuration same as that of the first embodiment other than the lower leg wearing portion5A. The lower leg wearing portion (shin cuff)5A is put on the lower leg U12of the user's right leg U1and has a substantially U shaped tubular shape as a whole so as to hold the lower leg U12from the front and rear sides. The tubular portion is a main body portion50A of the lower leg wearing portion5A. The main body portion50A is tapered from the upper side to the lower side. With a plan view of the main body portion50A of the lower leg wearing portion5A from an outer side (the right side) that is to be fixed to the lower leg link portion4, the main body portion50A may include a loop-shaped member that has a hole5Aa therein and is curved to hold the user's lower leg U12from the front and rear sides. The main body portion50A includes an upper portion and a lower portion having the hole5Aa therebetween. In the loop-shaped main body portion50A including the upper and lower portions, only the lower portion50A2is connected to a base portion52A that is fixed to the lower leg link portion, and the upper portion50A1is away from the base portion52A. Therefore, a gap5Ac is formed between the upper portion50A1and the base portion52A.

As illustrated inFIG. 15, the tubular main body portion50A has a space5Ab therein and the lower leg U12is inserted in the space5Ab. The front end portion of the main body portion50A is away from the rear end portion thereof and a gap5Ad is therebetween. The lower leg U12is inserted in and removed from the main body portion50A (the space5Ab) of the lower leg wearing portion5A through the gap. The lower leg wearing portion5A of this embodiment is made of synthetic resin that is processed into a predetermined shape and has effective strength and elasticity. Further, in the lower leg wearing portion5A of this embodiment, the upper portion50A1of the main body portion50A is away from the base portion52A that is to be fixed to the lower leg link portion4and movable in the front-rear direction, the right-left direction and up and down to some extent. Therefore, the main body portion50A of the lower leg wearing portion5A is in closely contact with the lower leg U12with being expanded slightly and effectively and the upper portion50A1of the main body portion50A is movable in the front-rear direction and in the right-left direction according to the motion of the lower leg U12. In the lower leg wearing portion5A of this embodiment, the lower leg U12of the user U (especially an upper portion of the lower leg U12) is movable in the front-rear direction and in the right-left direction to some extent with respect to the lower leg link portion4. Therefore, in the walking assistance device of this embodiment, the lower leg wearing portion5A is not in contact with the lower leg U12of the user U (front shin or a rear iliotibial portion) too strongly and the user is less likely to feel pain at the lower leg U12.

The conditions of the lower leg wearing portion5A such as a size, strength, elasticity are appropriately determined with considering the size, the shape, and the position of the user's lower leg U12. The lower leg wearing portion5A is detachably fixed to the inner side surface of the lower leg link portion4with two screw-shaped fixing members51A,51A. The screw-shaped fixing members51A,51A are inserted through the through holes42d,41din the lower leg link portion4and fixed to the lower leg link portion4. Distal end portions of the screw-shaped fixing members51A,51A are screwed into the base portion52A of the lower leg wearing portion5A.

Fourth Embodiment

Next, a fourth embodiment of the present invention will be described with reference toFIGS. 16 and 17.FIG. 16is a perspective view illustrating a cam adjusting device100used in a walking assistance device of the fourth embodiment.FIG. 17is an inner side view of the cam adjusting device100used in the walking assistance device of the fourth embodiment. The walking assistance device of this embodiment includes the cam adjusting device100that adjust a relative positional relation between a cam portion62Bb formed on a rotary plate62B and a roller portion94Ba of a cam follower94B. The cam adjusting device100mainly includes a servomotor101, a first pulley102, a timing belt103, and a second pulley104.

In the walking assistance device of this embodiment, one end of a waist shaft61B of a waist joint portion6B is fixed to a housing63B similarly to the first embodiment. In this embodiment, however, another end of the waist shaft61B is fixed to a mount plate60B. In this embodiment, an upper end portion of the mount plate60B is arranged in the receiver portion23of the waist wearing belt2similarly to the first embodiment. The rotary plate62B of this embodiment is supported on the waist shaft61B to rotate (swing) in the front-rear direction similarly to the first embodiment, however, the rotary plate62B is not fixed to the mount plate60B. The second pulley (a toothed pulley)104is supported on the waist shaft61B in this embodiment. The second pulley104is arranged between the rotary plate62B and the mount plate60B. The second pulley104is fixed to the rotary plate62B. Therefore, the rotary plate62B is rotated according to the rotation of the second pulley104around the waist shaft61B. A main body62Ba of the rotary plate62B has an outer appearance shape similar to that of the first embodiment. Namely, the rotary plate62B of this embodiment includes a cam portion62Bd and an outer surface (a cam surface)62Be similar to that of the first embodiment. The timing belt (a toothed belt)103is put on the second pulley104.

As illustrated inFIG. 16, the servomotor101is mounted on a rear side of the waist wearing belt2(a rear portion of the main body21). The servomotor101rotates a driving shaft (not illustrated) with using electric power supplied from a power supply device. The servomotor101controls the rotation of the driving shaft based on commands from a control device, which is not illustrated in the drawings. The driving shaft included in the servomotor101has a distal end portion and the first pulley102is mounted on the distal end portion. The first pulley102has a diameter that is smaller than the diameter of the second pulley104. The timing belt103is also put on the first pulley102. If the driving shaft of the servomotor102is rotated and the first pulley102is rotated, the timing belt103put on the first pulley102is rotated and also the second pulley104where the timing belt103is put is rotated. The rotary plate62B that is fixed to the second pulley104is rotated according to the rotation of the second pulley104. Accordingly, the position of the cam portion62Bd relative to the cam follower94B (the roller portion94Ba) is changed.

For example, if a control device (not illustrated) receives a certain signal input by the user U and transmits a driving signal to the servomotor101, the driving shaft of the servomotor101is rotated to rotate the second pulley104via the timing belt103so that the cam portion62Bd is shifted by a certain angle with respect to the cam follower94B (the roller portion94Ba). Accordingly, in the walking assistance device of this embodiment, the torque range of the torque generated by a torque generator9B is altered with using the cam adjusting device100. In this embodiment, the torque range is altered without taking apart the waist joint portion6B of the walking assistance device.

The torque generator9B of this embodiment has the torque properties similar to that of the first embodiment illustrated inFIG. 11. The torque properties of the torque generator9B are represented by the graph inFIG. 11wherein a lateral axis represents a cam follower angle θ2instead of the cam follower angle θ1. The cam follower angle θ2represents an angle θ (°) formed between the center line M of the cam portion62Bd passing through the center O of the waist shaft61B and a line passing through the center of the cam follower94B and the center O of the waist shaft61B.

In this embodiment, when the upper body (the waist U3) stands upright during walking, the mount plate60B mounted on the waist wearing belt2put on the waist U3is straight in the substantially vertical direction. In such a condition, the cam follower94B is tilted frontward at 20° with respect to the vertical direction G. Further, in this condition, if the cam portion62Bd (the rotary plate62) is arranged so that the cam follower94B is located at an angle of −20° rearward from the center line M of the cam portion62Bd and the thigh link portion3is moved in a range from the rearward −20° (absolute angle) to frontward 20° with respect to the vertical direction, the cam follower94B is moved in a range from −40° to 0° similarly to the first embodiment. The torque corresponding to the range of the angle θ2is generated.

The servomotor101is driven to rotate the second pulley104and alter the mount position of the cam portion62Bd (the mount position of the rotary plate62B) so that the cam follower94B is located at an angle of −40° rearward from the center line M of the cam portion62Bd. Then, if the thigh link portion3is moved in a range from the rearward −20° (absolute angle) to frontward 20° with respect to the vertical direction, the cam follower94B is moved in a range from −20° to −60°. Accordingly, the torque corresponding to the range of the angle θ2is generated and the torque range of the generated torque is higher than the torque range of the above case. The movement range of the cam follower94B with respect to the outer surface62Be is altered with using the cam adjusting device100to alter the range of the torque generated by the torque generator9B. Therefore, the user U may alter the movement range of the cam follower94B automatically and easily during walking.

Fifth Embodiment

Next, a fifth embodiment of the present invention will be described with reference toFIGS. 18 to 20.FIG. 18is a side view of a walking assistance device1A of the fifth embodiment. The walking assistance device1A of this embodiment mainly includes the waist wearing belt2, a thigh link portion3A, a lower leg link portion4A, a lower leg wearing portion5A, a waist joint portion6A, a knee joint portion7A, the thigh contact portion8A, and the torque generator9. The waist wearing belt2and the torque generator9included in the walking assistance device1A are same as those of the first embodiment.

In the walking assistance device1A of this embodiment, the thigh link portion3A and the lower leg link portion4A are detachable from the waist joint portion6A and the knee joint portion7A each of which is configured as a module.FIG. 19is a side view of the thigh link portion3A of the fifth embodiment. The thigh link portion3A and the lower leg link portion4A are formed by processing a metal plate into a predetermined shape, respectively, similarly to the first embodiment. Specifically, the thigh link portion3A is formed by connecting the thigh inner member31A and the thigh outer member32A to be opposed to each other. The thigh link portion3A includes a pair of tubular portions33A,34A and a plate-like connection portion35A that is located between the tubular portions33A,34A and connects them. The lower leg link portion4A is formed by connecting a lower leg inner member41A and a lower leg outer member42A to be opposed to each other. The lower leg link portion4A includes a pair of tubular portions43A,44A and a plate-like connection portion45A that is located between the tubular portions43A,44A and connects them.

An upper end portion3Aa of the thigh link portion3A is detachably mounted on a holder65A of the waist joint portion6A. A lower end portion3Ab of the thigh link portion3A is detachably mounted on a thigh side knee joint portion73A of the knee joint portion7A. An upper end portion4Aa of the lower leg link portion4A is detachably mounted on a lower leg side knee joint portion72A of the knee joint portion7A. The knee shaft71and the fixing member74included in the knee joint portion7A have configurations similar to those of the first embodiment.

FIG. 20is an exploded perspective view of a portion of the walking assistance device1A of the fifth embodiment in the vicinity of the knee joint portion7A. A mounting structure of the lower end portion3Ab of the thigh link portion3A and the thigh side knee joint portion73A of the knee joint portion7A will be described with reference toFIG. 20. The thigh side knee joint portion73A includes a main body73Aa that mainly overlaps the lower leg side knee joint portion72A and has a substantially disk-like shape, and a holder73Ab that is connected to an upper end of the main body73Aa and holds the lower end portion3Ab of the thigh link portion3A.

The holder73Ab includes a first holder portion173Ab and a second holder portion273Ab. The first holder portion173Ab extends upwardly from the main body73Aa and the second holder portion273Ab is a separate component from the first holder portion173Ab. The holder73Ab holds the lower end portion3Ab of the thigh link portion3A between the first holder portion173Ab and the second holder portion273Ab. The lower end portion3Ab (the lower end surface) of the thigh link portion3A is held to be in contact with an upper surface73Aa1of the main body73Aa where the first holder portion173Ab extends upward.

The first holder portion173Ab and the second holder portion273Ab have a gap73Ac therebetween and the lower end portion3Ab of the thigh link portion3A is arranged in the gap. The gap73Ac has a size corresponding to a thickness of the lower end portion3Ab. The first holder portion173Ab has a projection portion173Ab1. The projection portion173Ab1is fitted in a recess formed by the tubular portions33A,34A of the thigh link portion3A and the plate-like connection portion35A. The second holder portion273Ab has a projection portion273Ab1. The projection portion273Ab1is fitted in a recess formed by the tubular portions33A,34A of the thigh link portion3A and the plate-like connection portion35A.

The first holder portion173Ab has a through hole173ab2through the projection portion173Ab1. The second holder portion273Ab has a screw through hole273Ab2through the projection portion273Ab1. The lower end portion3Ab of the thigh link portion3A has a through hole232Ad through the connection portion35A. A screw273is inserted through the through hole173Ab2, the through hole232Ad and the screw through hole273Ab2to be tightened. Thus, the lower end portion3Ab of the thigh link portion3A is held between the first holder portion173Ab and the second holder portion273Ab and held by the holder73Ab with using the screw273. If the screw273is loosened and removed from the through hole173Ab2, the through hole232Ad and the screw through hole273Ab2, the thigh link portion3A is easily detached from the holder73Ab.

Next, a mounting structure of the upper end portion4Aa of the lower leg link portion4A and the lower leg side knee joint portion72A of the knee joint portion7A will be described with reference toFIG. 20. The lower leg side knee joint portion72A includes a main body72Aa that mainly overlaps the thigh side knee joint portion73A and has a substantially disk-like shape, and a holder72Ab that is connected to a lower end of the main body72Aa and holds the upper end portion4Aa of the lower leg link portion4A.

A basic configuration of the holder72Ab of the lower leg side knee joint portion72A is similar to that of the holder73Ab of the thigh side knee joint portion73A. Specifically, the holder72Ab includes a first holder portion172Ab and a second holder portion272Ab. The first holder portion172Ab is provided at the lower end of the main body72Aa and the second holder portion272Ab is a separate component from the first holder portion172Ab. The holder72Ab holds the upper end portion4Aa of the lower leg link portion4A between the first holder portion172Ab and the second holder portion272Ab. The upper end portion4Ab (the upper end surface) of the lower leg link portion4A is held to be in contact with a lower surface72Aa1of the main body72Aa where the first holder portion172Ab extends downward.

The first holder portion172Ab has a projection portion172Ab1and a through hole172Ab2. The second holder portion272Ab has a projection portion272Ab1and a screw through hole272Ab2. The first holder portion172Ab and the second holder portion272Ab have a gap72Ac therebetween and the upper end portion4Aa of the lower leg link portion4A is arranged in the gap. The gap72Ac has a size corresponding to a thickness of the upper end portion4Aa. The upper end portion4Aa of the lower leg link portion4A has a through hole142Ad through the connection portion45A.

A screw272is inserted through the through hole172Ab2, the through hole142Ad and the screw through hole272Ab2to be tightened. Thus, the upper end portion4Aa of the lower leg link portion4A is held between the first holder portion172Ab and the second holder portion272Ab and held by the holder72Ab with using the screw272. If the screw272is loosened and removed from the through hole172Ab2, the through hole142Ad and the screw through hole272Ab2, the lower leg link portion4A is easily detached from the holder72Ab.

The holder65A of the waist joint portion65A has the configuration similar to that of the holder72Ab of the lower leg side knee joint portion72A. The holder65A detachably holds the upper end portion3Aa of the thigh link portion3A. The upper end portion3Aa of the thigh link portion3A has a through hole132Ad that is used when the thigh link portion3A is mounted on the holder65A of the waist joint portion6A.

As illustrated inFIG. 18, the lower end portion4Ab of the lower leg link portion4A is covered with a protection cap10A similar to that of the first embodiment. The protection cap10A is detachable from the lower end portion4Ab of the lower leg link portion4A.

In the walking assistance device1A of this embodiment, the thigh link portion3A and the lower leg link portion4A may be replaced with other components. For example, alternative seven kinds of thigh link portions3A (an example of a thigh link portion group) are previously prepared. The seven kinds of thigh link portions3A differ in the longitudinal length thereof by every 20 mm. Specifically, the thigh link portions3A having entire lengths of 200 mm, 220 mm, 240 mm, 260 mm, 280 mm, 300 mm and 320 mm are previously prepared. Alternative two kinds of lower leg link portions4A (an example of a lower leg link portion group) are previously prepared. The two kinds of lower leg link portions4A differ in the longitudinal direction by every 60 mm. Specifically, the lower leg link portions4A having entire lengths of 200 mm and 260 mm are previously prepared. As described above, the kinds of the thigh link portions3A and the lower leg link portions4A that are previously prepared are determined according to the users' builds. They are determined based on Japanese builds and correspond to most of Japanese users. The kinds of the link portions may correspond to people of other nationalities if the maximum value or the minimum value of the entire lengths is changed.

A user or a practitioner such as a doctor or a physical therapist selects one of the various kinds of thigh link portions3A and the selected thigh link portion3A is used in the walking assistance device1A. The user or the practitioner selects one of the various kinds of lower leg link portions4A and the selected lower leg link portion4A is used in the walking assistance device1A.

As is in this embodiment, the thigh link portion3A and the lower leg link portion4A are configured to be detachably mounted on the waist joint portion6aand the knee joint portion7A each of which is modularized. Therefore, the lengths of the thigh link portion and the lower leg link portion are changed according to the user's request (for example, a user's body size) if necessary.

In another embodiment, each of the thigh link portion3A and the lower leg link portion4A of the walking assistance device1A may be replaced with that of the same kind (for example, a new thing link portion3aor a new lower leg link portion4A of the same kind or the same size).

One of various kinds of lower leg wearing portions5A (a lower leg wearing portion group) is selected according to a size and a shape of the user's lower leg (including a lower limb orthosis).

Sixth Embodiment

Next, a sixth embodiment of the present invention will be described with reference toFIGS. 21 to 27. In this embodiment, a walking assistance device including a weight will be described.FIG. 21is a side view of a walking assistance device1A where a weight200is attached. InFIG. 21, the weight200is attached to the walking assistance device1A of the fifth embodiment.

The weight200is attached to the thigh link portion3A and the lower leg link portion4A of the walking assistance device1A. A weight200ais attached to the thigh link portion3A and a weight200bis attached to the lower leg link portion4A.

FIG. 22is an enlarged view of the weight200aattached to the thigh link portion3A, andFIG. 23is a cross sectional view taken along line C-C′ inFIG. 22. The weight200ahas an elongated bar-like shape as a whole and is fit in the recess portion formed by the tubular portions33A,34A and the connection portion35A of the thigh link portion3A. The weight200aincludes projections201that are fit in the recess portion of the thigh link portion3A.

The weight200ais mainly made of metal material such as brass. In this embodiment, the weight200ahas a magnet (not illustrated) built-in and is adhered to the metal thigh link portion3A with a magnetic force. The weight200ais fixed to the thigh link portion3A with using a fixing member210a(210) having a substantially arched shape. The fixing member210a(210) is made of plastic material or metal material. As illustrated inFIG. 23, two end portions211,211of the fixing member210a(210) are curved like a hook to face each other. The two end portions211,211are elastically deformed to be fit to end portions of the thigh link portion3A, respectively, so that the fixing member210a(210) is fixed to the thigh link portion3A. The weight200ais held between the fixing member210a(210) and the thigh link portion3A. If the fixing member210a(210) is pulled away from the thigh link portion3A, the end portions211are elastically deformed outwardly and the fixing member210a(210) is easily detached from the thigh link portion3A. Thus, the weight200ais detachably mounted on the thigh link portion3A.

The weight200bthat is attached to the lower leg link portion4A has a basic configuration same as that of the weight200afor the thigh link portion3A. The weight200bis attached to the lower leg link portion4A with using a fixing member210b(210).

In another embodiment, the weight200may not include the magnet and may be attached to a predetermined position of the thigh link portion3A or the lower leg link portion4A only with the fixing member210.

In this embodiment, the weight200aattached to the thigh link portion3A weighs 130 g and the weight200battached to the lower leg link portion4A weighs 60 g. Weights of the weight200aattached to the thigh link portion3A and the weight200battached to the lower leg link portion4A may be changed according to the user's request. A user or a practitioner such as a doctor or a physical therapist selects one of various kinds of weights (a weight group) having different weights according to the condition of the user's affected leg that the walking assistance device is to be put on, the user's symptom and a walking condition. The weight200may be attached to both of the thigh link portion3A and the lower leg link portion4A, or may be attached to only one of the thigh link portion3A and the lower leg link portion4A.

The weight200amay be attached to a portion of the thigh link portion3A on the upper end portion3Aa side or on the lower end portion3Ab side. The weight200amay be attached to a middle portion of the thigh link portion3A. Namely, the attachment position of the weight200ais not limited but may be determined according to the user's symptom and walking condition by the user or the practitioner such as a doctor and a physical therapist.

(Simulation of Motion of Walking Assistance Device with Weight)

Motions of the thigh link portion and the lower leg link portion of the walking assistance device with the weight are simulated with using a computer. Conditions for the simulation are as follows.

Simulated motions of a walking assistance device having a mechanism using double link portions are illustrated inFIG. 24. An angle (absolute angle) θ10and an angle (relative angle) θ20are illustrated inFIG. 24. The angle (absolute angle) θ10is formed between the thigh link portion3A that swings about the center of the waist axis61and a vertical line G1passing through a center P of the knee shaft71, and the angle (relative angle) θ20is formed between the thigh link portion3A and the lower leg link portion4A that swing about the center P of the knee shaft71. An arrow F inFIG. 24represents a frontward direction of the walking assistance device. As illustrated inFIG. 24, the motion of the walking assistance device1A of a double link portions model (double pendulum model) including the thigh link portion3A and the lower leg link portion4A is simulated. The walking assistance device of the double link portions model includes the thigh link portion3A having a length of 320 mm and the lower leg link portion4A having a length of 260 mm. The weights of the thigh link portion3A and the lower leg link portion4A are 100 g and 70 g, respectively. The weight attached to the thigh link portion3A weights 130 g and the weight attached to the lower leg link portion4A weighs 60 g. In an initial condition, the thigh link portion3A and the lower leg link portion4A that are straight are tilted rearward by 10° from a straight posture. In the simulation, a torque is applied to the thigh link portion3A and the lower leg link portion4A that are in the initial condition around the center O of the waist shaft61to perform the double pendulum movement. The torque is reduced to a range from 1 Nm to 0 Nm while the thigh link portion3A swings (seeFIG. 25). The simulation is performed three times with changing the position of the weights. Namely, one of the simulations is performed with the weights on the upper end portions of the thigh link portion3A and the lower leg link portion4A, another one is performed with the weights on the middle portions thereof, and the other one is performed with the weights on the lower end portions thereof.

FIG. 25illustrates graphs one of which represents time-dependent change of the angles (absolute angle) θ10and another one of which represents time-dependent change of the angles (relative angle) θ20. The angle (absolute angle) θ10is formed between the thigh link portion3A that swings about the center O of the waist axis61and the vertical line G1passing through the center P of the knee shaft71, and the angle (relative angle) θ20is formed between the thigh link portion3A and the lower leg link portion4A that swing about the center P of the knee shaft. The angle (absolute angle) θ10formed between the thigh link portion3A that swings about the center O of the waist axis61and the vertical line G1passing through the center P of the knee shaft71is represented with plus (+) when the thigh link portion3A is located frontward with respect to the vertical line G1and the angle θ10is represented with minus (−) when the thigh link portion3A is located rearward with respect to the vertical line G1(seeFIG. 24). Further, the graph L1represents time-dependent change with the weights on the upper end portions of the thigh link portion3A and the lower leg link portion4A. The graph L2represents time-dependent change with the weights on the middle portions of the thigh link portion3A and the lower leg link portion4A. The graph L3represents time-dependent change with the weights on the lower end portions of the thigh link portion3A and the lower leg link portion4A.

The angle (relative angle) θ20that is formed between the thigh link portion3A and the lower leg link portion4A that swing about the center P of the knee shaft is 0° when the thigh link portion3A and the lower leg link portion4A are on a line. The angle θ20is greater than 0° when the thigh link portion3A and the lower leg link portion4A approach each other. InFIG. 25, the graph L11represents time-dependent change with the weights on the upper end portions of the thigh link portion3A and the lower leg link portion4A. The graph L12represents time-dependent change with the weights on the middle portions of the thigh link portion3A and the lower leg link portion4A. The graph L13represents time-dependent change with the weights on the lower end portions of the thigh link portion3A and the lower leg link portion4A.

As illustrated inFIG. 25, if the weights are attached to the upper end portions or the middle portions, the time-dependent change (inclination of the graph) of the swing angles θ10of the thigh link portion3A becomes greater and the maximum value of the knee angle θ20becomes greater, and a walking pitch (time) is decreased. If the weights are attached to the lower end portions, the maximum value of the knee angle θ20becomes smaller and the walking pitch (time) is increased. The walking assistance device itself having no power can change a swing pattern by changing the attachment positions of the weights. Therefore, the balanced weight (weights of the weights and balanced attachment positions of the weights) is kept in the walking assistance device according to the user's symptom and walking condition to improve walking.

(Actual Measurement of Motion of Walking Assistance Device with Weight)

Next, when a user wearing the walking assistance device with the weights walks, the motions of the thigh link portion and the lower leg link portion of the walking assistance device during the walking are analyzed in the following steps.

In the walking assistance device1A with the weights illustrated inFIG. 21, a marker is provided on each of the waist joint portion (the waist shaft), the knee joint portion (the knee shaft), and the lower end portion (the protection cap10A) of the lower leg link portion4A. A user (a person being tested) who wears the walking assistance device1A with the markers on his/her right leg walks. The length of the thigh link portion3A of the walking assistance device1A is 320 mm and the weight of 190 g is attached to the upper end portion of the thigh link portion3A. The length of the lower leg link portion4A is 260 mm and the weight of 190 g is attached to the upper end portion of the lower leg link portion4A.

Next, images of the user who is wearing the walking assistance device1A and walks are taken with a highly sensitive camera to obtain videos of the motions of the walking assistance device1A. Tracing data of each marker is extracted from the obtained videos (image data). Time-dependent change data of the angles (absolute angle) θ10and time-dependent change data of the angles (relative angle) θ20are obtained from the extracted data. The angle (absolute angle) θ10is formed between the thigh link portion3A that swings about the center O of the waist axis61and the vertical line G1passing through the center P of the knee shaft71and the angle (relative angle) θ20is formed between the thigh link portion3A and the lower leg link portion4A that swing about the center P of the knee shaft. The measurement method of the angles θ10and the angles θ20is same as that in the above simulations (seeFIG. 24).

Data of the angles θ10and data of the angles θ20for one cycle of the walking motion are obtained. In this embodiment, a walking cycle starts at a double support phase when the right leg wearing the walking assistance device1A is located on a rear floor surface and the left leg is located on a front floor surface. The walking cycle is illustrated inFIG. 26. The obtained data of the angles θ10and the angles θ20is represented as graphs inFIG. 27. Data of the angles θ10and the angles θ20obtained with the walking assistance device1A without the weights are obtained as a comparative example. The data of the comparative example is represented as graphs inFIG. 27.

InFIG. 27, a solid line L21represents data (a graph) of the angles θ20(the knee angle) with the walking assistance device1A including the weights, and a dotted line L22represents data (a graph) of the angles θ20(the knee angle) with the walking assistance device1A without the weights.

InFIG. 27, a solid line L31represents data (a graph) of the angles θ10(the swing angle of the thigh link portion) with the walking assistance device1A with the weights, and a dotted line L32represents data (a graph) of the angles θ10(the swing angle of the thigh link portion) with the walking assistance device1A without the weights. A period t1inFIG. 27represents the double support phase with the weights and a period t2represents the double support phase without the weights.

As illustrated inFIG. 27, when the leg wearing the walking assistance device1A is at a free leg phase, the maximum value of the angle θ20(the knee angle) is slightly smaller in the walking assistance device1A with the weights than that without the weights (in a range from 0.2 to 0.4 seconds inFIG. 27) and the time-dependent change of the angles θ10(the swing angle of the thigh link portion) is slightly greater in the walking assistance device1A with the weights than that without the weights (in the vicinity of 0.2 seconds inFIG. 27). The user wearing the walking assistance device1A with the weights feels like his/her leg being moved forward rather than being lifted up and feels like increasing the length of stride. The movement distance of the leg is 123 cm without the weights and 134 cm with the weights. The walking pitch (time) is smaller in the device with the weights than the device without the weights. The user wearing the walking assistance device1A increases the length of stride and walks smoothly. Accordingly, the walking is effectively improved.

Other Embodiments

The present invention is not limited to the embodiments described above with reference to the drawings and following embodiments are included in the technologies of the present invention.

(1) In the above embodiments, the walking assistance device is put on the right leg. However, the walking assistance device may be put on the left leg in another embodiment.

(2) In the above embodiments, the walking assistance device is put on only one leg (the right leg). However, a walking assistance device may be mounted on right and left portions of the waist wearing belt in another embodiment.

(3) In the above embodiments, the thigh link portion and the lower leg link portion are connected to each other via the knee joint portion. However, in another embodiment, the walking assistance device of the first embodiment may not include the knee joint portion, the lower leg link portion, and the lower leg wearing portion. Such a walking assistance device assists the motion of the user's leg (the right leg, for example) wearing the walking assistance device during the walking. In such a configuration, it is preferable to hook a belt on the thigh contact portion8and provide it around the thigh U11.

(4) In the above embodiments, the thigh link portion includes the thigh contact portion. However, the thigh link portion may not include the thigh contact portion in another embodiment.

(5) In the above embodiments, the mount plate is mounted on the waist wearing belt with the hook-and-loop fastener. However, the mount plate may be mounted on the waist wearing belt with other known mounting means in another embodiment. It is preferable that the mount plate is detachably mounted on the waist wearing belt as is in the above embodiments.

(6) According to the third embodiment, the lower leg wearing portion5A has the gap5Ac between the upper portion50A1of the main body portion50A and the base portion52A that fixes the lower wearing portion5A to the lower leg link portion4. However, a hinge portion may be provided to connect the base portion52A and the upper portion50A1in another embodiment. With such a hinge portion, the upper portion50A1of the main body portion50A included in the lower leg wearing portion5A is allowed to move in the front-rear direction and is less likely to move in the up-down direction. Namely, with the hinge portion, the lower leg wearing portion is less likely to move in the up-down direction so that the motion of the lower leg link portion is likely to be transferred to the user's lower leg.

(7) In the above embodiments, each of the components constituting each of the thigh link portion and the lower leg link portion is made of metal plate. However, each of the components constituting each of the thigh link portion and the lower leg link portion may be a resin member (a resin molded item, for example).

(8) In the above embodiments, the torque generator is configured to generate a torque to move the thigh link portion frontward of the user. However, the toque pattern generated by the torque generator may be changed in another embodiment. For example, the torque generator may be configured to generate a toque to move the thigh link portion toward the user that is in an opposite direction from that in the first embodiment.

(9) In the first embodiment, the mount plate60has a pair of fixing through holes60c,60c.However, the mount plate60may have two pairs of fixing through holes60c,60cor more. The adjacent pairs of the fixing through holes60c,60care away from each other by 10° (namely, the fixing through holes60care formed around the waist shaft61at every 10°). Accordingly, the mounting position of the cam portion62d(the outer surface62e) of the rotary plate62(the position of the cam portion62dwith respect to the cam follower94(the roller portion94a)) is changed by every 5° according to combinations of the fixing through holes60cand the fixing through holes62c,62cthat are formed in the rotary plate62(at every 15°). Thus, the mounting position (the angle) of the cam portion62dmay be adjusted with using the fixing through holes62c,62cof the rotary plate62and also the fixing through holes60c,60cformed in the mount plate60.

(10)FIG. 28is a cross-sectional view of a thigh link portion3B according to a modification. The thigh link portion3B is formed by pressing a tubular metal member (having a pipe shape) to form a connection portion35B and elongated tubular portions33B,34B that sandwich the connection portion35B therebetween. The thigh link portion3B includes a through hole132Bd in an upper end portion thereof as is inFIG. 28. Thus, the thigh link portion3B is produced by processing one tubular member. The lower leg link portion may have the configuration same as that of the thigh link portion3B. The tubular portions33B,34B of the thigh link portion3B does not necessarily have circular cross sectional shape but may have an ellipsoidal cross sectional shape or a polygonal cross sectional shape (such as a square).

(11)FIG. 29is a cross-sectional view of a thigh link portion3C according to another modification. The thigh link portion3C is formed by processing a metal plate to have tubular shapes at two side portions. The thigh link portion3C includes a plate-like connection portion35C at a middle portion thereof and a pair of tubular portions33C,34C that sandwich the connection portion35C therebetween. A thickness of the connection portion35C is effectively determined according to the strength required for the thigh link portion3C. Portions of the metal plate corresponding to the tubular portions33C,34C may be subjected to connection processing such as welding. The thigh link portion3C includes through hole132Cd in an upper end portion thereof as illustrated inFIG. 29. Thus, the thigh link portion3C may be produced by processing a metal plate member. The lower leg link portion may have the configuration same as that of the thigh link portion3C.

(12)FIG. 30is a cross-sectional view of a thigh link portion3D according to another different modification. The thigh link portion3D is formed by processing a metal plate to have square tubular shapes at two side portions. The thigh link portion3D includes a plate-like connection portion35D at a middle portion thereof and a pair of tubular portions33D,34D that sandwich the connection portion35D therebetween. A thickness of the connection portion35D is effectively determined according to the strength required for the thigh link portion3D. Portions of the metal plate corresponding to the tubular portions33D,34D may be subjected to connection processing such as welding. The thigh link portion3D includes through hole132Dd in an upper end portion thereof as illustrated inFIG. 30. Thus, the thigh link portion3D may be produced by processing a metal plate member. The lower leg link portion may have the configuration same as that of the thigh link portion3D.

(13) Other than SECC, known metal members such as cold rolled carbon steel sheets and strip (SPCC) or hot rolled mil steel plates, sheets and strip (SPHC) may be used for the thigh link portion. The metal members may be subjected to surface treatment such as galvanizing and coating.

(14)FIG. 31is a rear view of a walking assistance device1B of another different embodiment. The walking assistance device1B includes the thigh link portion3A and the lower leg link portion4B that are same as those of the walking assistance device1A of the fifth embodiment. The walking assistance device1B includes the waist joint portion6A and the knee joint portion7A that are same as those in the fifth embodiment. The lower leg link portion4A of the walking assistance device1B does not include the lower leg wearing portion. The lower leg link portion4A is overlapped with the thigh link portion3A in the right-left direction inFIG. 31such that the protection cap10A protecting the lower end of the lower leg link portion4A faces upward. The thigh contact portion8B is mounted on an inner side of the lower leg link portion4A (facing the user's thigh). The thigh contact portion8B is fixed to the lower leg link portion4A and the thigh link portion3A with using a screw-shaped fixing member80. A belt (not illustrated) may be hooked on the thigh contact portion8B to put around the user's thigh and fix the link portions. Thus, the walking assistance device1B including the lower leg link portion4A and the thigh link portion3A that are overlapped with each other may be used.

(15)FIG. 32is a perspective view of a waist wearing belt2C of another different modification. The basic configuration of the waist wearing belt2C is same as that in the first embodiment. The waist wearing belt2C includes a receiver portion23C that differs from the bag-shaped one in the first embodiment and is an open-close type. Specifically, the receiver portion23C includes a receiver main body portion23C1and a receiver cover portion23C2. The receiver main body portion23C1is put on a rear side surface of the mount plate60of the waist joint portion6. The receiver cover portion23C2covers a front side surface of the mount plate60. A rear end portion of the receiver cover portion23C2is integrally connected to the receiver main body portion23C1. A front end portion of the receiver cover portion23C2is removable from the receiver main body portion23C1. The receiver cover portion23C2has a plurality of projected fitting portions25and the receiver main body portion23C1has a plurality of recess fitting portions26that are fitted to the fitting portions25to be fixed thereto. The receiver cover portion23C2is attached to the receiver main body portion23C1by the fitting of the fitting portions25and the fitting portions26. The receiver cover portion23C2is detached from the receiver main body portion23C1by releasing the fitting. A hook-and-loop fastener portion27is attached to a surface of the receiver main body portion23C1and the hook-and-loop fastener portion27is adhered to another hook-and-loop fastener portion attached to the mount plate60. The receiver portion23C of the waist wearing belt2C is the open-close type as described before. Therefore, the mount plate60is mounted on the receiver portion27C (the hook-and-loop fastener portion27) with the receiver cover portion23C2being open. Also, the mount plate60is detached from the receiver portion27C (the hook-and-loop fastener portion27) with the receiver cover portion23C2being open. Therefore, the mount plate60is easily mounted on and removed from the waist wearing belt2C.

(16)FIG. 33is a perspective view of a mount plate60D according to another different modification. The mount plate60D is mounted on the waist wearing belt2similarly to the first embodiment. Unlike the first embodiment, the mount plate60D includes a plate-like main body60Da including an upper main body portion60Da1and a lower main body portion60Da2. The upper main body portion60Da1and the lower main body portion60Da2are connected to each other via a hinge portion H. The hinge portion H is located in a portion of the main body portion60Da between the waist joint portion6and the receiver portion23of the waist wearing belt2. The mount plate60D is folded at the hinge portion H so that the hinge portion H is moved outwardly and the upper main body portion60Da1and the lower main body portion60Da2approach each other. Provided with such a hinge portion H, the mount plate60D is folded to fit to the shape of the user's waist side portion. As a result, the mount angles of the thigh link portion and the lower leg portion of the walking assistance device with respect to the lower leg are adjusted.

(17)FIG. 34is a view illustrating the walking assistance devices1each of which is put on each leg. As illustrated inFIG. 34, the walking assistance device1may be put on each of the user's two legs. The walking assistance device1for a right leg and that for a left leg have symmetric configurations and basically have a same configuration. With the walking assistance devices1put on the respective two legs, the walking action of the user U is supported and improved (corrected).

EXPLANATION OF SYMBOLS