Folding wheelchair

Abstract

The cushion frame and chassis frame are firmly engaged and integrated to improve the rigidity of the folding wheelchair's body. [Solution] The upper edge portion 31 of the chassis frame 30 has an outer embankment portion 33 that protrudes upward on the outer side in the vehicle width direction and an inner embankment portion 34 that protrudes upward on the inner side in the vehicle width direction. A recess 34b is formed in the inner embankment portion 34. The lower part of the cushion frame 72 is provided with an engagement mechanism 110 which includes an engagement piece portion 111 whose upper part is supported by an axle 113 so that the engagement portion 111b formed at the lower part of the convex shape portion 111a swings in the vehicle width direction, and a biasing member 115 that constantly biases and displaces the engagement portion 111b outward in the vehicle width direction.

Description

Technical Field

[0001] The present disclosure relates to a folding wheelchair configured to be foldable.

Background Art

[0002] For example, Patent Document 1 discloses a folding wheelchair in which a cushion frame that supports a seat cushion portion on which a wheelchair user sits is detachable from the wheelchair body. This type of foldable wheelchair body has a pair of left and right chassis frames and a link mechanism that connects the left and right chassis frames and transitions between a folded state and a deployed state. When not in use, after removing the cushion frame from the wheelchair body, the left and right chassis frames can be brought close to each other in the vehicle width direction by the operation of the link mechanism, making it compact and enhancing portability.

[0003] Also, in Patent Document 1, in a state where the cushion frame is attached to the wheelchair body, the cushion frame is fixed to the left and right chassis frames by pins that protrude in the front-rear direction from the cushion frame.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, in a folding wheelchair, as described above, the left and right chassis frames are connected by a link mechanism, and moreover, in order to enable transition between the folded state and the deployed state, there are a plurality of movable parts such as a rotating shaft, etc., so the vehicle body rigidity decreases.

[0006] Furthermore, the cushion frame described in Patent Document 1 has a structure in which it is fixed by inserting pins into the left and right chassis frames, which makes it easy for play to occur between the pins and the insertion holes in the chassis frames, making it difficult to improve the rigidity of the vehicle body using the cushion frame.

[0007] This disclosure is made in view of the above points, and its purpose is to improve the rigidity of the body of a folding wheelchair by firmly engaging and integrating the cushion frame and the chassis frame. [Means for solving the problem]

[0008] To achieve the above objective, one aspect of the present disclosure may provide a folding wheelchair comprising: a pair of left and right chassis frames pivotally supporting wheels outward in the vehicle width direction; a link mechanism connecting the insides of the left and right chassis frames and causing the left and right chassis frames to transition between a folded state in which they are close to each other in the vehicle width direction and an unfolded state in which they are furthest apart in the vehicle width direction; and a removable cushion frame placed from above on the upper part of the left and right chassis frames in the unfolded state.

[0009] Each of the left and right chassis frames includes an upper edge portion extending in the front-rear direction. Each of the left and right upper edges has an outer embankment portion that protrudes upward and extends in the front-rear direction on the outer side in the vehicle width direction, and an inner embankment portion that protrudes upward and extends in the front-rear direction on the inner side in the vehicle width direction so as to be opposite the outer embankment portion in the vehicle width direction.

[0010] A recess is formed on a part of the surface of the inner embankment facing the outer embankment, and the cushion frame includes a pair of left and right longitudinal members that extend in the front-rear direction to match the left and right chassis frames in the deployed state, and a transverse member that connects the left and right longitudinal members in the vehicle width direction, and the lower part of the longitudinal member has a downward-facing convex shape that fits between the outer embankment and the inner embankment on the upper edge when placed on the left and right chassis frames, and an engagement mechanism is provided which includes an engagement piece whose upper part is supported by an axis so that the engagement portion formed at the lower part of the convex shape swings in the vehicle width direction, and a biasing member that constantly biases and displaces the engagement portion outward in the vehicle width direction.

[0011] When the cushion frame is placed in a predetermined position on the chassis frame in its deployed state, the engaging portion swings inward in the vehicle width direction, entering and engaging with the recess of the inner embankment, thereby integrating the cushion frame and the chassis frame.

[0012] In this configuration, when the cushion frame is placed in a predetermined position on the left and right chassis frames in their deployed state, the convex shape of the engaging piece of the engagement mechanism provided on the longitudinal member of the cushion frame fits between the outer and inner embankments of the upper edge of the chassis frame, thereby positioning the longitudinal member relative to the chassis frame in the vehicle width direction. Furthermore, the engaging piece rotates around its axis, causing the engaging portion to swing inward in the vehicle width direction. The engaging portion, having swung inward in the vehicle width direction, enters and engages with the recess of the inner embankment. At this time of engagement, since the longitudinal member is positioned relative to the chassis frame in the vehicle width direction, it becomes possible to firmly engage the engaging portion with the recess, and the cushion frame and chassis frame are firmly integrated.

[0013] On the other hand, when the cushion frame, which is placed in a predetermined position on the chassis frame, is removed from the chassis frame, the biasing force of the biasing member displaces the engaging portion outward in the vehicle width direction. As a result, the engaging portion does not remain engaged in the recess, and the cushion frame can be smoothly removed from the chassis frame.

[0014] The engaging portion can be elongated in the front-to-back direction, and the formation range of the engaging portion in the front-to-back direction may include the center of gravity of the wheelchair occupant seated. With this configuration, the weight of the wheelchair occupant seated on the seat cushion is transmitted to the convex portion via the longitudinal member, and the convex portion can be reliably fitted between the outer and inner embankments.

[0015] A bottom surface may be formed between the lower part of the outer embankment and the lower part of the inner embankment on the upper edge. In this case, when the cushion frame is placed in a predetermined position on the chassis frame in an unfolded state, the convex shape can rotate around the axis such that the lower part of the convex shape contacts the bottom surface, causing the engaging part to swing inward in the vehicle width direction. This allows the engaging part to engage with the recess using, for example, the weight of the cushion frame or the force applied when the cushion frame is pressed downwards.

[0016] The shaft supporting the engaging piece may be located outside the center of the vertical member in the vehicle width direction. In this case, the engaging portion can be positioned inside the center of the vertical member in the vehicle width direction. This allows the engaging portion to be reliably swung inward in the vehicle width direction simply by bringing the lower part of the convex shape into contact with the bottom surface.

[0017] A recess may be formed at the lower part of the inner embankment facing the outer embankment, and a contact surface extending in the front-rear and up-down directions may be formed above the recess on the inner embankment facing the outer embankment. In this case, when the cushion frame is placed in a predetermined position on the chassis frame in the deployed state, the contact area between the convex shape and the inner embankment can be increased by bringing the part above the engaging portion on the inner surface in the vehicle width direction of the convex shape into contact with the contact surface, thereby further increasing rigidity.

[0018] The surface of the outer soil portion facing the inner soil portion may be inclined so as to be located more inward in the vehicle width direction as it goes downward. In this case, the surface on the outer side in the vehicle width direction of the vertical member can be formed along the surface of the outer soil portion facing the inner soil portion. Thereby, not only can the contact area between the outer soil portion and the vertical member be widened, but when the cushion frame is placed at a predetermined position of the chassis frame, the vertical member can be positioned by being sandwiched in the vehicle width direction between the outer soil portion and the inner soil portion, and the engaging portion can be firmly engaged with the concave portion.

Advantages of the Invention

[0019] As described above, the cushion frame and the chassis frame can be firmly engaged and integrated to improve the vehicle body rigidity of the folding wheelchair.

Brief Description of the Drawings

[0020] [Figure 1] FIG. 1 is a perspective view of a wheelchair according to an embodiment of the present invention as viewed from the front. [Figure 2] FIG. 2 is a perspective view of the wheelchair as viewed from the left side. [Figure 3] FIG. 3 is a left side view of the wheelchair. [Figure 4] FIG. 4 is a perspective view of the seat cushion as viewed from the left side. [Figure 5] FIG. 5 is a view corresponding to FIG. 2 showing the state where the seat cushion is removed. [Figure 6] FIG. 6 is a perspective view of the wheelchair body with the left and right wheels omitted as viewed from the front. [Figure 7] FIG. 7 is a cross-sectional view taken along a vertical plane passing through the center in the left-right direction of the wheelchair and extending in the front-rear direction. [Figure 8] FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. 6. [Figure 9] FIG. 9 is a perspective view of the inner soil portion as viewed from below. [Figure 10] FIG. 10 is a perspective view of the seat cushion as viewed from below. [Figure 11] Figure 11 is a perspective view of the right-side engagement unit and its vicinity, seen from the lower right. [Figure 12] Figure 12 is a perspective view of the right-side engagement unit and its vicinity, viewed from the left side. [Figure 13] Figure 13 is a perspective view of the section along line XIII-XIII in Figure 7. [Figure 14] Figure 14 is an enlarged view of the section along line XIII-XIII in Figure 7. [Figure 15] Figure 15 is a diagram equivalent to Figure 14, showing the state in which the engaging portion swings outward in the vehicle width direction. [Figure 16] Figure 16 is a diagram equivalent to Figure 14, showing the state in which the convex shape is in contact with the bottom surface of the upper edge. [Figure 17] Figure 17 is a diagram equivalent to Figure 14, showing the state in which the engaging portion is swinging inward in the vehicle width direction. [Modes for carrying out the invention]

[0021] Embodiments of the present invention will be described in detail below with reference to the drawings. The following description of preferred embodiments is essentially illustrative and is not intended to limit the present invention, its applications, or its uses.

[0022] Figure 1 is a perspective view of the wheelchair 1 according to an embodiment of the present invention, viewed from the front and diagonally above. Figure 2 is a perspective view of the wheelchair 1 according to an embodiment of the present invention, viewed from the left side. Figure 3 is a left side view of the wheelchair 1. Figure 4 shows the removed seat cushion 3, and Figure 5 shows the wheelchair body 2 with the seat cushion 3 removed.

[0023] This wheelchair 1 is configured so that the seat cushion 3 can be removed from the wheelchair body 2 without the need for tools, and comprises a wheelchair body 2 and a separate seat cushion 3 that can be attached to and removed from the wheelchair body 2. The wheelchair body 2 with the seat cushion 3 removed is configured to be foldable, and therefore the wheelchair 1 according to this embodiment is a foldable wheelchair in which a wheelchair user can sit, i.e., a folding wheelchair.

[0024] In this description of the embodiment, the direction of travel of the wheelchair 1 when moving forward is simply referred to as "forward," and the front of the wheelchair 1 corresponds to the front of the wheelchair user (not shown) seated in the wheelchair 1. Similarly, the direction of travel of the wheelchair 1 when moving backward is simply referred to as "rear," and the rear of the wheelchair 1 corresponds to the rear of the wheelchair user seated in the wheelchair 1. The front-rear direction of the wheelchair 1 is also the longitudinal direction of the vehicle body. Furthermore, the left side of the wheelchair user seated in the wheelchair 1 is the left side of the vehicle body of the wheelchair 1, and is simply referred to as "left." In addition, the right side of the wheelchair user seated in the wheelchair 1 is the right side of the vehicle body of the wheelchair 1, and is simply referred to as "right." The left-right direction of the wheelchair 1 is the width direction of the vehicle body, and is also referred to as the vehicle width direction. Furthermore, the "upper side" of the wheelchair 1 is the side that is at the top when placed on a horizontal surface in a seated state, and the "lower side" of the wheelchair 1 is the side that is at the bottom when placed on a horizontal surface in a seated state.

[0025] The wheelchair body 2 is the part that makes up the chassis of the wheelchair 1. The wheelchair body 2 includes a pair of left and right drive wheels 10 and 11, a pair of left and right casters 12 and 13, a pair of left and right chassis frames 20 and 30, a linkage mechanism 40 (shown in Figures 5 and 6), and a foldable footrest 60. The seat cushion 3 is placed on the pair of left and right chassis frames 20 and 30 at a specific front-to-back position.

[0026] The left drive wheel 10 is pivotally supported on the left side of the left chassis frame 20 in the vehicle width direction (left side). The right drive wheel 11 is pivotally supported on the right side of the right chassis frame 30 in the vehicle width direction (right side). The left drive wheel 10 and the right drive wheel 11 are large-diameter wheels that a wheelchair user seated on the seat cushion 3 can hold by hand and rotate forward or backward, and can also be called drive rear wheels as they are located at the rear of the wheelchair body 2. The left drive wheel 10 and the right drive wheel 11 have a structure in which rubber tires 10b and 11b are attached to the outer circumference of the wheels 10a and 11a, respectively. Handrims 10c and 11c are provided on the outer side of the wheels 10a and 11a in the vehicle width direction, respectively, for the wheelchair user to hold by hand when driving.

[0027] On the other hand, the left caster 12 and the right caster 13 are wheels used to change the direction of travel of the wheelchair 1, and are smaller in diameter than the left drive wheel 10 and the right drive wheel 11. Since the left caster 12 and the right caster 13 are located on the front side of the wheelchair body 2, they can also be called front wheels for changing the direction of travel.

[0028] As shown in Figures 5 and 6, the left chassis frame 20 comprises a left upper edge portion 21 and a left caster support portion 22. The left upper edge portion 21 extends in the longitudinal direction at a height between the central axis (wheel axis) 10d of the left drive wheel 10 and the upper outer edge of the left drive wheel 10, and is located close to the inner side (right side) in the vehicle width direction of the left drive wheel 10. Since this is the part on which the left side of the seat cushion 3 is placed, it can also be called the left cushion mounting member. The central axis 10d of the left drive wheel 10 is the rotational axis of the wheel 10a and is pivotally supported below the left upper edge portion 21 on the left chassis frame 20. The outer edge of the left drive wheel 10 is composed of the outer edge of the tire 10b.

[0029] The left caster support portion 22 extends forward from the middle of the left upper edge portion 21 in the front-rear direction, and is positioned lower as it approaches the front end. The left caster 12 is mounted to the front end of the left caster support portion 22 so as to be able to pivot around an axis that extends in the vertical direction.

[0030] The right chassis frame 30 has a symmetrical structure with the left chassis frame 20 and includes a right upper edge portion 31 and a right caster support portion 32. The right upper edge portion 31 extends in the longitudinal direction at a height between the central axis (wheel axis) 11d (shown in Figure 7) of the right drive wheel 11 and the upper outer edge of the right drive wheel 11, at a position close to the inner side (left side) in the vehicle width direction of the right drive wheel 11, and since it is the part on which the right side of the seat cushion 3 is placed, it can also be called the right cushion placement member. The central axis 11d of the right drive wheel 11 is the rotational axis of the wheel 11a and is pivotally supported below the right upper edge portion 31 on the right chassis frame 30. The outer edge of the right drive wheel 11 is composed of the outer edge of the tire 11b. The upper outer edge of the right drive wheel 11 is composed of the outer edge of the tire 11b that is located above the central axis 11d of the right drive wheel 11.

[0031] The right caster support portion 32 is formed to extend forward from the middle of the right upper edge portion 31 in the front-rear direction, and to be positioned lower as it approaches the front end. The right caster 13 is mounted to the front end of the right caster support portion 32 so as to be able to pivot around an axis that extends in the vertical direction.

[0032] The link mechanism 40 shown in Figure 6 connects the inner side of the left chassis frame 20 in the vehicle width direction to the inner side of the right chassis frame 30 in the vehicle width direction, and is a folding mechanism that transitions between a folded state in which the left chassis frame 20 and the right chassis frame 30 are close to each other in the vehicle width direction and an unfolded state in which the left chassis frame 20 and the right chassis frame 30 are farthest apart in the vehicle width direction. Because the wheelchair 1 includes the link mechanism 40, the wheelchair body 2 can be transitioned from the unfolded state to the folded state and from the folded state to the unfolded state without the use of tools or the like. When the wheelchair body 2 is in the unfolded state, the seat cushion 3 can be attached to the wheelchair body 2 by placing it from above on the upper part of the left chassis frame 20 and the upper part of the right chassis frame 30. On the other hand, the wheelchair body 2 can be folded by removing the seat cushion 3 from the wheelchair body 2.

[0033] In this embodiment, the seat cushion 3 is detachably attached to the wheelchair body 2. Therefore, when the wheelchair 1 is not in use, the seat cushion 3 can be removed from the wheelchair body 2, allowing the wheelchair body 2 and the seat cushion 3 to be separated, making them lighter and easier to transport, as well as more compact. Furthermore, since the wheelchair body 2 is foldable, the wheelchair body 2 becomes more compact.

[0034] In other words, the link mechanism 40 comprises an upper link 41 and a lower link 42, and an upper connecting member 43 and a lower connecting member 44. The left chassis frame 20 includes a left link bracket 26 to which the upper link 41 and the lower link 42 are attached. The right chassis frame 30 also includes a right link bracket 36 to which the upper link 41 and the lower link 42 are attached. The left link bracket 26 and the right link bracket 36 are made of plate material or the like that extends in the vertical and front-rear directions.

[0035] The upper link 41 includes a left link component 41a and a right link component 41b. The left end of the left link component 41a of the upper link 41 is rotatably attached to the left link bracket 26 of the left chassis frame 20 around an axis extending in the front-rear direction. The right end of the right link component 41b of the upper link 41 is rotatably attached to the right link bracket 36 of the right chassis frame 30 around an axis extending in the front-rear direction. The right end of the left link component 41a and the left end of the right link component 41b are rotatably attached to the upper connecting member 43 around an axis extending in the front-rear direction.

[0036] The lower link 42 is a link positioned below the upper link 41, and like the upper link 41, it includes a left link component 42a and a right link component 42b. The left end of the left link component 42a of the lower link 42 is rotatably attached to the left link bracket 26 of the left chassis frame 20 around an axis extending in the front-rear direction. The right end of the right link component 42b of the lower link 42 is rotatably attached to the right link bracket 36 of the right chassis frame 30 around an axis extending in the front-rear direction. The right end of the left link component 42a and the left end of the right link component 42b of the lower link 42 are rotatably attached to the lower connecting member 44 around an axis extending in the front-rear direction. The left link component 42a of the lower link 42 has a predetermined inclination angle such that it is positioned lower as it moves to the right, and the right link component 42b has a predetermined inclination angle such that it is positioned lower as it moves to the left.

[0037] The upper connecting member 43 and the lower connecting member 44 are separate. A gripping portion 45 is attached to the upper connecting member 43. When the gripping portion 45 is lifted by hand, the upper connecting member 43 attempts to move upward, which pulls the right end of the left link component 41a and the left end of the right link component 41b of the upper link 41 upward. As a result, the left link component 41a pivots upward around the axis on the left chassis frame 20 side, and the right link component 41b pivots upward around the axis on the right chassis frame 30 side, causing the upper link 41 to fold upward so that it becomes convex.

[0038] Since the left link component 42a and the right link component 42b of the lower link 42 have a predetermined inclination angle, the left link component 42a swings downward with the axis on the left chassis frame 20 side as the pivot point, and the right link component 42b swings downward with the axis on the right chassis frame 30 side as the pivot point, causing the lower link 42 to fold so that it becomes convex downwards.

[0039] The folding operations of the upper link 41 and the lower link 42 are almost simultaneous. When the upper link 41 and the lower link 42 are folded, the left chassis frame 20 and the right chassis frame 30 are folded in a way that brings them close to each other in the vehicle width direction.

[0040] On the other hand, when a force is applied to the left chassis frame 20 and the right chassis frame 30, which are in a folded state, in a direction that separates them in the vehicle width direction, the left link component 41a of the upper link 41, which was convex upward, swings downward with the axis on the left chassis frame 20 side as the pivot point, and the right link component 41b swings downward with the axis on the right chassis frame 30 side as the pivot point, resulting in the upper link 41 becoming elongated in the left-right direction. The left link component 42a of the lower link 42, which was convex downward, swings upward with the axis on the left chassis frame 20 side as the pivot point, and the right link component 41b swings upward with the axis on the right chassis frame 30 side as the pivot point, resulting in the lower link 42 becoming elongated in the left-right direction.

[0041] The upper link 41 and the lower link 42 deploy almost simultaneously. When the upper link 41 and the lower link 42 deploy, the left chassis frame 20 and the right chassis frame 30 can be separated to their maximum extent in the vehicle width direction, resulting in the deployed state.

[0042] The structure of the link mechanism 40 is not limited to the structure described above, and any structure that can transition between a state in which the left chassis frame 20 and the right chassis frame 30 are close together in the vehicle width direction and an expanded state in which they are furthest apart in the vehicle width direction is acceptable. For example, the structure may be such that both the upper link 41 and the lower link 42 are bent upwards, or the structure may be such that both the upper link 41 and the lower link 42 are bent downwards.

[0043] As shown in Figure 6, the right upper edge portion 31 has an outer embankment portion 33 that protrudes upward and extends in the longitudinal direction on the outer side in the vehicle width direction, and an inner embankment portion 34 that protrudes upward and extends in the longitudinal direction on the inner side in the vehicle width direction, facing the outer embankment portion 33 in the vehicle width direction. The outer embankment portion 33 is continuous from near the rear end of the right upper edge portion 31 to the middle in the longitudinal direction. On the other hand, the rear end of the inner embankment portion 34 is set forward from the rear end of the right upper edge portion 31, and there is a gap between the rear end of the inner embankment portion 34 and the rear end of the right upper edge portion 31. The outer embankment portion 33 extends further forward than the front end of the inner embankment portion 34, and therefore the longitudinal dimension of the inner embankment portion 34 is shorter than the longitudinal dimension of the outer embankment portion 33.

[0044] The right-side link bracket 36 is fastened below the inner ridge portion 34 on the right-side upper edge portion 31. The portion of the right-side upper edge portion 31 where the inner ridge portion 34 is formed has increased rigidity and strength because the inner ridge portion 34 functions like a rib. By fastening the right-side link bracket 36 to this portion with increased rigidity and strength, the mounting strength of the right-side link bracket 36 can be increased.

[0045] As shown in Figure 8, the height of the inner embankment 34 is lower than the height of the outer embankment 33, and the upper end of the outer embankment 33 is located above the upper end of the inner embankment 34. Furthermore, the left side of the outer embankment 33 (the inner side in the vehicle width direction) is the first inner surface 33a that faces the inner embankment 34. The first inner surface 33a is formed as an inclined surface that is positioned further outward in the vehicle width direction as it goes upward. In other words, the surface of the outer embankment 33 that faces the inner embankment 34 is inclined to be positioned further inward in the vehicle width direction as it goes downward.

[0046] The inner embankment portion 34 is made of a separate component from the lower part of the right upper edge portion 31 and the components that make up the outer embankment portion 33. Figure 9 is a perspective view from below of the inner embankment portion 34 separated from the components that make up the lower part of the right upper edge portion 31 and the outer embankment portion 33. As shown in this figure, the inner embankment portion 34 can be removed from the main body portion of the right upper edge portion 31. This allows the inner embankment portion 34 to be made of a different material from the main body portion of the right upper edge portion 31, such as a high-strength metal material. Alternatively, the inner embankment portion 34 may be integrally molded with the main body portion of the right upper edge portion 31.

[0047] The right side (outer side in the vehicle width direction) of the inner embankment portion 34 is a second inner side 34a that faces the first inner side 33a of the outer embankment portion 33 in the vehicle width direction. A right-side recess 34b is formed at the lower part of the second inner side 34a, which is recessed inward in the vehicle width direction and opens outward in the vehicle width direction. The right-side recess 34b is elongated in the front-rear direction. Above the right-side recess 34b of the second inner side 34a, a right-side contact surface 34c is formed, to which a part of the engaging pieces 111 and 112 (shown in Figures 11 and 12), which will be described later, abuts. The right-side contact surface 34c extends in the front-rear and up-down directions and is formed as an inclined surface that is positioned more inward in the vehicle width direction as it goes upward.

[0048] As shown in Figure 7, the center of gravity G of the wheelchair occupant is located between the central axis 11d of the right drive wheel 11 and the front end of the right chassis frame 30. When a wheelchair occupant of standard build sits on the seat cushion 3, the anterior-posterior position of the center of gravity G is as shown in Figure 7. This center of gravity G is located in front of the central axis 11d of the right drive wheel 11 (central axis 10d of the left drive wheel 10) and behind the front end of the right chassis frame 30 (front end of the left chassis frame 20). Even if the wheelchair occupant's weight or build changes slightly, the center of gravity G of the wheelchair occupant will remain located between the central axis 11d of the right drive wheel 11 and the front end of the right chassis frame 30.

[0049] The longitudinal range of the outer embankment 33 and the inner embankment 34 includes the seated center of gravity G of the wheelchair occupant. That is, the outer embankment 33 has a long shape in the longitudinal direction, and in a side view, it extends both forward and backward of the seated center of gravity G of the wheelchair occupant. The inner embankment 34 also has a long shape in the longitudinal direction, and in a side view, it extends both forward and backward of the seated center of gravity G of the wheelchair occupant.

[0050] As shown in Figure 8, a bottom surface 35 extending in the vehicle width direction is formed between the lower part of the first inner surface 33a of the outer embankment 33 and the lower part of the second inner surface 34a of the inner embankment 34 on the right upper edge 31. This bottom surface 35 also extends in the front-rear direction.

[0051] As shown in Figure 6, the left upper edge portion 21 has a symmetrical structure with the right upper edge portion 31. A portion of the left upper edge portion 21 in the front-rear direction has an outer embankment portion 23 that protrudes upward and extends in the front-rear direction on the outer side in the vehicle width direction, and an inner embankment portion 24 that protrudes upward and extends in the front-rear direction on the inner side in the vehicle width direction, facing the outer embankment portion 23 in the vehicle width direction. The front-rear dimension of the inner embankment portion 24 is shorter than the front-rear dimension of the outer embankment portion 23. The left link bracket 26 is fastened below the inner embankment portion 24 on the left upper edge portion 21. This increases the mounting strength of the left link bracket 26.

[0052] The height of the inner embankment 24 is lower than the height of the outer embankment 23. Furthermore, the formation range of the outer embankment 23 and the inner embankment 24 in the front-rear direction includes the seated center of gravity G of the wheelchair occupant (shown in Figure 7). In addition, the left side of the outer embankment 23 (inner side in the vehicle width direction) is a first inner side 23a facing the inner embankment 24. The first inner side 23a is formed as an inclined surface that slopes outward in the vehicle width direction as it goes upward. Furthermore, the right side of the inner embankment 24 (outer side in the vehicle width direction) is a second inner side 24a facing the outer embankment 23. At the bottom of the second inner side 24a, a left-side recess 24b is formed, which is recessed inward in the vehicle width direction and opens outward in the vehicle width direction. The left-side recess 24b has a long shape in the front-rear direction. Above the left recess 24b of the second inner surface 24a, a left contact surface 24c is formed, to which parts of the engaging pieces 111 and 112, described later, abut. The left contact surface 24c extends in the front-rear and up-down directions and is formed as an inclined surface that is positioned inward in the vehicle width direction as it goes higher.

[0053] Between the lower part of the first inner surface 23a of the outer embankment 23 and the lower part of the second inner surface 24a of the inner embankment 24 on the left upper edge portion 21, a bottom portion 25 is formed that extends in the vehicle width direction and the front-rear direction.

[0054] As shown in Figure 4, the seat cushion 3 comprises a seat surface 70, a seat back 71, a cushion frame 72 supporting the seat surface 70, a seat back member 73 supporting the seat back 71, and a hinge portion 74. The seat surface 70 is the part on which the wheelchair occupant sits, and is made of, for example, foam or fabric, forming a seat surface that extends in the front-to-back and left-to-right directions. The seat back 71 is the part that supports the area near the wheelchair occupant's waist, and is made of, for example, foam or fabric.

[0055] The seat cushion 3 is equipped with hinge portions 74 on the left and right sides, and seat back members 73 on the left and right sides, respectively. The left hinge portion 74 is located at the rear left side of the cushion frame 72, and the left seat back member 73 is supported by the left hinge portion 74 so as to be rotatable in the front-rear direction. The right hinge portion 74 is located at the rear right side of the cushion frame 72, and the right seat back member 73 is supported by the right hinge portion 74 so as to be rotatable in the front-rear direction.

[0056] Each of the left and right hinge portions 74 has a pivot shaft 74a extending in the vehicle width direction. The pivot shaft 74a is a component that constitutes the pivot point of the hinge portion 74. Figure 4 shows the seat back member 73 in the upright position, which is the position in which a wheelchair occupant can sit. By rotating the seat back member 73 forward around the pivot shaft 74a from the upright position, it can be moved to the tilted-forward position (not shown). The tilted-forward position is the position taken when removing the seat cushion 3 from the chassis frame 20, 30. Also, by rotating the seat back member 73 upward around the pivot shaft 74a from the tilted-forward position, it can be moved back to the upright position. In this way, the seat back member 73 is configured to be displaceable between the upright position and the tilted-forward position.

[0057] As shown in Figure 10, the seat cushion 3 also includes left and right claw portions 75. The left and right claw portions 75 are connected to the pivot points of the hinge portions 74 on the left and right seat back members 73, respectively. The left claw portion 75 rotates in a direction toward and toward the rear end of the left upper edge portion 21 in response to the rotation of the left seat back member 73. Similarly, the right claw portion 75 rotates in a direction toward and toward the rear end of the right upper edge portion 31 in response to the rotation of the right seat back member 73.

[0058] When the left and right seat back members 73 are raised to the upright position, the left claw portion 75 enters and engages with a recess (not shown) formed at the rear end of the left upper edge portion 21, and the right claw portion 75 enters and engages with a recess (not shown) formed at the rear end of the right upper edge portion 31.

[0059] As shown in Figure 10, the cushion frame 72 has a pair of left and right vertical members 80, 81 and a pair of front and rear horizontal members 82, 83 that connect the left and right vertical members 80, 81 in the vehicle width direction. The left vertical member 80 is a member that extends in the front-rear direction at a position that overlaps with the left upper edge portion 21 in a plan view. The left vertical member 80 is formed to extend forward from the front end of the left upper edge portion 21 and cover its upper part, and the portion that extends forward from the front end of the left upper edge portion 21 is called the front extension portion 80e. The front extension portion 80e is used as a place for wheelchair occupants to place their hands when getting in and out of the wheelchair.

[0060] The right vertical member 81 is a member that extends in the front-rear direction at a position that overlaps with the right upper edge portion 31 in a plan view. The right vertical member 81 is formed to extend forward from the front end of the right upper edge portion 31 and cover its upper surface, and the portion that extends forward from the front end of the right upper edge portion 31 is called the forward extension portion 81e. The forward extension portion 81e is used as a place for wheelchair users to rest their hands when getting in and out of the wheelchair.

[0061] Since the left upper edge 21 and the right upper edge 31 are approximately parallel, the left vertical member 80 and the right vertical member 81 are also approximately parallel. The left vertical member 80 and the right vertical member 81 are designed to align with the left upper edge 21 and the right upper edge 31 when unfolded, from above.

[0062] The front transverse member 82 extends in the vehicle width direction below the front of the seat surface 70 and is a member that connects the left longitudinal member 80 to the front of the center in the longitudinal direction and the right longitudinal member 81 to the front of the center in the longitudinal direction. The rear transverse member 83 extends in the vehicle width direction below the rear of the seat surface 70 and is a member that connects the left longitudinal member 80 to the rear of the center in the longitudinal direction and the right longitudinal member 81 to the rear of the center in the longitudinal direction.

[0063] A left-side engagement mechanism 100 is provided at the middle of the lower part of the left vertical member 80 in the front-rear direction, which engages with the left upper edge portion 21. Similarly, a right-side engagement mechanism 110 is provided at the middle of the lower part of the right vertical member 81 in the front-rear direction, which engages with the right upper edge portion 31.

[0064] Figures 11 and 12 show the right-side engagement mechanism 110. The right-side engagement mechanism 110 comprises front and rear engagement pieces 111 and 112, front and rear support shafts 113 and 114 that support the front and rear engagement pieces 111 and 112 respectively, and front and rear biasing members 115 and 116 that bias the front and rear engagement pieces 111 and 112 respectively. The front and rear engagement pieces 111 and 112 are aligned in the front-rear direction.

[0065] The front engaging piece 111 has a shape that is elongated in the front-rear direction. As shown in Figure 13, when the cushion frame 72 is placed in a predetermined position on the chassis frames 20 and 30 in the deployed state, the inner embankment 34 is positioned on the inside of the front engaging piece 111 in the vehicle width direction. Therefore, the formation range of the front engaging piece 111 in the front-rear direction includes the seated center of gravity G of the wheelchair occupant, similar to the inner embankment 34. The rear engaging piece 112 also has a shape that is elongated in the front-rear direction, and the inner embankment 34 is positioned on the inside of the rear engaging piece 112 in the vehicle width direction.

[0066] As shown in Figure 11, the upper part of the front engaging piece 111 is rotatably supported by a front support shaft 113 that extends in the front-rear direction. The axial intermediate portion (front-rear intermediate portion) of the front support shaft 113 is supported by a front bearing portion 120 provided at the lower part of the right longitudinal member 81. The front support shaft 113 is located outside the center of the right longitudinal member 81 in the vehicle width direction.

[0067] As shown in Figures 13 and 14, the front engaging piece 111 has a downward-facing convex portion 111a that fits between the outer embankment portion 33 and the inner embankment portion 34 of the right upper edge portion 31 when placed on the right chassis frame 30. Below the convex portion 111a, an engaging portion 111b is formed that enters and engages with the right recess 34b. The engaging portion 111b is positioned inward from the center in the vehicle width direction of the right longitudinal member 81 and is composed of a curved surface that bulges inward in the vehicle width direction.

[0068] Since the upper part of the front engaging piece 111 is rotatably supported by the front support shaft 113 extending in the front-rear direction, the engaging portion 111b formed at the lower part of the convex-shaped portion 111a becomes swingable in the vehicle width direction. The front biasing member 115 is a member that constantly biases and displaces the engaging portion 111b outward in the vehicle width direction. That is, as shown in Figure 14, the front biasing member 115 is made of, for example, a coil spring. In the case of the front biasing member 115 made of a coil spring, the front biasing member 115 has an annular portion 115a in the center, and the front support shaft 113 is inserted through this annular portion 115a. One leg portion 115b of the front biasing member 115 abuts from below against the lower surface of the right vertical member 81. The other leg portion 115c of the front biasing member 115 is inserted into and locked to the concave surface 111c formed on the outer side in the vehicle width direction of the front engaging piece portion 111. Therefore, the front biasing member 115 applies a biasing force outward in the vehicle width direction, which is the right side in Figure 14, to the lower part of the engaging portion 111b.

[0069] Figure 15 shows the state in which the engaging portion 111b swings outward in the vehicle width direction. When the engaging portion 111b swings outward in the vehicle width direction, the stopper portion 120a provided on the front bearing portion 120 defines the limit position of outward swing of the engaging portion 111b in the vehicle width direction. Specifically, as shown in Figure 11, the stopper portion 120a is formed to protrude downward from the front bearing portion 120. Since the front and rear sides of the front engaging piece 111 are supported by the front support shaft 113, the middle part of the front engaging piece 111 in the front-rear direction is open, and the stopper portion 120a abuts against this middle part of the front engaging piece 111 from the outside in the vehicle width direction, preventing the engaging portion 111b from swinging further outward in the vehicle width direction. The position and shape of the stopper portion 120a allow the limit position of the outward swing of the engaging portion 111b in the vehicle width direction to be arbitrarily defined.

[0070] Figure 16 shows the state immediately after the cushion frame 72 is placed in its predetermined position on the unfolded chassis frames 20 and 30. As shown in Figure 16, the lower part of the convex portion 111a is in contact with the bottom surface 35 of the upper right side portion 31. The portion of the convex portion 111a that contacts the bottom surface 35 is positioned inward in the vehicle width direction from the front bearing portion 120. With this positional relationship, simply moving the cushion frame 72 downward causes the convex portion 111a to rotate around the front support shaft 113, as shown in Figure 17, by causing the lower part of the convex portion 111a to contact the bottom surface 35, thereby swinging the engaging portion 111b inward in the vehicle width direction. As the engaging portion 111b swings inward in the vehicle width direction, as shown in Figures 13 and 14, it enters and engages with the right-side recess 34b of the inner bank portion 34, and the cushion frame 72 and the chassis frame 30 are integrated. The force exerted when the engaging portion 111b contacts the inner surface of the right-side recess 34b increases as the downward load acting on the cushion frame 72 increases. Therefore, when a wheelchair occupant is seated on the cushion frame 72, the engaging portion 111b comes into strong contact with the inner surface of the right-side recess 34b, and the cushion frame 72 and the chassis frame 30 are firmly integrated.

[0071] When the cushion frame 72 is placed in a predetermined position on the chassis frame 30 in the deployed state, the part of the convex-shaped portion 111a above the engaging portion 111b on the inner surface in the vehicle width direction contacts the contact surface 34c. In addition, the outer surface of the right vertical member 81 in the vehicle width direction is formed to follow the first inner surface 33a of the outer embankment portion 33, and contacts the first inner surface 33a when the cushion frame 72 is placed in a predetermined position on the chassis frame 30 in the deployed state.

[0072] To remove the cushion frame 72 from the chassis frame 30, simply lift the cushion frame 72. When the cushion frame 72 is lifted, the right vertical member 81 and the right upper edge portion 31 will be in the positional relationship shown in Figure 17, and then in the positional relationship shown in Figure 16. As the positional relationship changes in this way, the convex portion 111a rotates around the front support shaft 113 so as to swing the engaging portion 111b outward in the vehicle width direction, and ends up in a state where it is swung outward in the vehicle width direction, as shown in Figure 15.

[0073] As shown in Figure 11, the rear engaging piece 112 is configured and operates similarly to the front engaging edge 111. That is, the upper part of the rear engaging piece 112 is rotatably supported by the rear support shaft 114. The axial intermediate portion (intermediate portion in the front-rear direction) of the rear support shaft 114 is supported by the rear bearing portion 121 provided at the lower part of the right longitudinal member 81.

[0074] The rear engaging piece 112 has a downward-facing convex portion 112a that fits between the outer embankment portion 33 and the inner embankment portion 34 of the right upper edge portion 31 when it is placed on the right chassis frame 30. An engaging portion 112b is formed at the lower part of the convex portion 112a that enters and engages with the right recess 34b.

[0075] Since the upper part of the rear engaging piece 112 is rotatably supported by a rear support shaft 114 extending in the front-rear direction, the engaging portion 112b at the lower part of the convex-shaped portion 112a becomes swingable in the vehicle width direction. The rear biasing member 116 is a member that constantly biases and displaces the engaging portion 112b outward in the vehicle width direction, and is made of a coil spring or the like, similar to the front biasing member 115.

[0076] A stopper portion 121a is provided on the rear bearing portion 121. The stopper portion 121a defines the limit position of the outward swing of the engaging portion 112b in the vehicle width direction. The convex portion 112a rotates around the rear support shaft 114 so that the lower part of the convex portion 112a abuts against the bottom surface portion 35, causing the engaging portion 112b to swing inward in the vehicle width direction. As a result, the engaging portion 112b enters and engages with the right-side recess 34b of the inner bank portion 34, and the cushion frame 72 and the chassis frame 30 are integrated.

[0077] As shown in Figure 10, the left-side engagement mechanism 100 has a symmetrical structure with respect to the right-side engagement mechanism 110. Specifically, the left-side engagement mechanism 100 comprises front and rear engagement pieces 101 and 102, front and rear support shafts 103 and 104 that support the front and rear engagement pieces 101 and 102 respectively, and front and rear biasing members 105 and 106 that bias the front and rear engagement pieces 101 and 102 respectively.

[0078] The upper part of the front engaging piece 101 of the left-side engaging mechanism 100 is rotatably supported by the front support shaft 103. The axial intermediate portion (intermediate portion in the front-rear direction) of the front support shaft 103 is supported by the front bearing portion 130 provided at the lower part of the left-side longitudinal member 80.

[0079] The front engaging piece 101 has a downward-facing convex portion 101a that fits between the outer embankment portion 23 and the inner embankment portion 24 of the left upper edge portion 21 when it is placed on the left chassis frame 20. An engaging portion (not shown) is formed at the lower part of the convex portion 101a that enters and engages with the left recess 24b.

[0080] Since the upper part of the front engaging piece 101 is rotatably supported by a front support shaft 104 that extends in the front-rear direction, the engaging portion at the lower part of the convex-shaped portion 101a becomes swingable in the vehicle width direction. The front biasing member 106 is a member that constantly biases and displaces the engaging portion outward in the vehicle width direction, and is made of a coil spring or the like.

[0081] A stopper portion (not shown) is provided on the front bearing portion 130. The stopper portion defines the limit position of the outward swing of the engaging portion in the vehicle width direction. The convex portion 101a rotates around the front support shaft 103 so that the lower part of the convex portion 101a abuts against the bottom surface portion 25, causing the engaging portion to swing inward in the vehicle width direction. As a result, the engaging portion enters and engages with the left recess 24b of the inner bank portion 24, and the cushion frame 72 and the chassis frame 20 are integrated.

[0082] The upper part of the rear engaging piece 101 of the left-side engaging mechanism 100 is rotatably supported by the rear support shaft 104. The axial intermediate portion (intermediate portion in the front-rear direction) of the rear support shaft 104 is supported by the rear bearing portion 131 provided at the lower part of the left-side longitudinal member 80.

[0083] The rear engaging piece 102 has a downward-facing convex portion 102a that fits between the outer embankment portion 23 and the inner embankment portion 24 of the left upper edge portion 21 when placed on the left chassis frame 20. An engaging portion (not shown) is formed at the lower part of the convex portion 102a that enters and engages with the left recess 24b.

[0084] Since the upper part of the rear engaging piece 102 is rotatably supported by a rear support shaft 104 that extends in the front-rear direction, the engaging portion at the lower part of the convex-shaped portion 102a becomes swingable in the vehicle width direction. The rear biasing member 106 is a member that constantly biases and displaces the engaging portion outward in the vehicle width direction, and is made of a coil spring or the like.

[0085] A stopper portion (not shown) is provided on the rear bearing portion 131. The stopper portion defines the limit position of the outward swing of the engaging portion in the vehicle width direction. The convex portion 102a rotates around the rear support shaft 104 so that the lower part of the convex portion 102a abuts against the bottom surface portion 25, causing the engaging portion to swing inward in the vehicle width direction. As a result, the engaging portion enters and engages with the left recess 24b of the inner bank portion 24, and the cushion frame 72 and the chassis frame 20 are integrated.

[0086] The embodiments described above are merely illustrative in all respects and should not be interpreted restrictively. Furthermore, any modifications or changes that fall within the equivalent scope of the claims are all within the scope of the present invention. For example, the biasing member according to the present invention may be composed of springs other than coil springs, or elastic members such as rubber. [Industrial applicability]

[0087] As explained above, the wheelchair relating to this disclosure can be used, for example, when the seat cushion and chassis can be separated. [Explanation of Symbols]

[0088] 1 Wheelchair 2. Wheelchair chassis 3 Seat cushions 10, 11 Drive wheels 30 Chassis Frame 31 Upper part 33 Outer bank 33a 1st inner surface 34 Inner embankment 34a 2nd inner surface 34b recess 34c Contact surface 35 Bottom part 40 Link mechanism 72 Cushion Frame 80, 81 vertical members 82, 83 Horizontal members 110 Engagement mechanism 111 Engaging piece 111a Convex shape part 111b Engagement part 113 Spindle 115 Biasing member

Claims

1. A folding wheelchair comprising: a pair of left and right chassis frames that pivotally support the wheels outward in the vehicle width direction; a link mechanism that connects the insides of the left and right chassis frames and allows the left and right chassis frames to transition between a folded state in which they are close to each other in the vehicle width direction and an unfolded state in which they are furthest apart in the vehicle width direction; and a removable cushion frame that is placed on top of the left and right chassis frames in the unfolded state from above, The left and right chassis frames each include an upper portion extending in the front-rear direction, Each of the left and right upper edges has an outer embankment portion that protrudes upward and extends in the front-rear direction on the outer side in the vehicle width direction, and an inner embankment portion that protrudes upward and extends in the front-rear direction on the inner side in the vehicle width direction so as to be opposite to the outer embankment portion in the vehicle width direction. A recess is formed in a part of the surface of the inner embankment facing the outer embankment, The cushion frame includes a pair of left and right longitudinal members that extend in the front-rear direction, matching the left and right chassis frames in the deployed state, and a transverse member that connects the left and right longitudinal members in the vehicle width direction. The lower part of the vertical member is provided with an engagement mechanism which includes an engagement piece whose upper part is supported by a shaft so as to swing in the vehicle width direction, and a biasing member that constantly biases and displaces the engagement piece outward in the vehicle width direction, and an engagement piece whose upper part is supported by a shaft so as to swing in the vehicle width direction, and an engagement member which is provided at the lower part of the vertical member which has a downward-facing convex shape that fits between the outer embankment and the inner embankment of the upper part of the upper edge when mounted on the left and right chassis frames, and A folding wheelchair in which, when the cushion frame is placed in a predetermined position on the chassis frame in an unfolded state, the engaging portion swings inward in the width direction of the vehicle, enters and engages with the recess of the inner bank, and the cushion frame and the chassis frame become one.

2. In the folding wheelchair according to claim 1, The aforementioned engaging portion has a shape that is elongated in the front-to-back direction. A folding wheelchair in which the formation range of the engagement portion in the front-to-back direction includes the seated center of gravity of the wheelchair occupant.

3. In the folding wheelchair according to claim 1, Between the lower part of the outer embankment and the lower part of the inner embankment in the upper portion, a bottom surface is formed. A folding wheelchair wherein, when the cushion frame is placed in a predetermined position on the chassis frame in an unfolded state, the convex portion rotates around the axis such that the lower part of the convex portion contacts the bottom surface, causing the engaging portion to swing inward in the vehicle width direction.

4. In the folding wheelchair according to claim 3, The shaft supporting the engagement piece is provided outside the center of the longitudinal member in the vehicle width direction, The engagement portion is positioned inward from the center of the vertical member in the vehicle width direction, in a folding wheelchair.

5. In the folding wheelchair according to claim 1, The recess is formed in the lower part of the surface of the inner embankment facing the outer embankment, A contact surface is formed in the inner embankment portion that extends in the front-rear direction and the up-down direction above the recess on the surface facing the outer embankment portion. A folding wheelchair in which, when the cushion frame is placed in a predetermined position on the chassis frame in an unfolded state, the part of the convex-shaped portion above the engaging portion on the inner surface in the vehicle width direction contacts the contact surface.

6. In the folding wheelchair according to claim 1, The surface of the outer embankment facing the inner embankment is inclined so that it is located further inward in the vehicle width direction as it goes downwards. A folding wheelchair in which the outer surface of the longitudinal member in the vehicle width direction is formed to conform to the surface of the outer embankment facing the inner embankment.

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