Wheelchair

Abstract

To provide a wheelchair that is hard to overturn rearward even if body weight of a user seated on the seat part takes rearward and that therefore has excellent stability.SOLUTION: A tilting frame part 41 in which a front shaft 42 provided with a main wheel 3 and a rear shaft 43 provided with an auxiliary wheel 5 are integrally formed is installed, in a base frame part 11 having a front wheel 4, in a tiltable manner in a position rearward from a rear end of a seat part 6. Also, the rear shaft 43 of the tilting frame part 41 is structured in a downward energized manner by a gas spring 34. According to such a structure, even if a user puts on the body weight rearward, overturning rearward is unlikely, with fear for overturning can be suppressed. Furthermore, by the tilting of the tilting frame part 41, the front wheel 4, the main wheel 3, and the auxiliary wheel 5 can track in accordance with a road surface, so that there is excellent road surface followability and that stable running on various road surfaces is made possible.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a six-wheel type wheelchair having main wheels, front wheels disposed in front of the main wheels, and auxiliary wheels disposed behind the main wheels on both the left and right sides.

Background Art

[0002] For example, in Patent Document 1, a six-wheel type wheelchair is proposed. This conventional configuration includes a movable part composed of a large wheel support frame rotatably connected to the main body part and disposed substantially vertically, and upper and lower rear frames protruding rearward from the large wheel support frame. A main wheel is rotatably connected to the large wheel support frame, and an auxiliary wheel is rotatably connected to the rear end of the rear frame. Here, the upper end of the large wheel support frame of the movable part is rotatably connected to a position directly below the seat part of the main body part. Further, a telescopic member is provided with one end pivotally attached to the main body part and the other end pivotally attached to the rear frame. In such a conventional configuration, when a weight is applied behind the seat part, as the telescopic member expands and contracts, the main body part tilts rearward with respect to the large wheel frame, and the front wheels can be easily lifted.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in wheelchairs, those having a reclining mechanism capable of changing the inclination of the backrest part are generally known. In such a configuration, when the backrest part is tilted backward, the weight of the user applied to the backrest part tends to increase. Also, in a wheelchair having a tilt mechanism that tilts the seat part and the backrest part integrally, similarly, the weight of the user applied to the backrest part in the tilted state tends to increase. Such reclining and tilting mechanisms can be applied to the wheelchair described in Patent Document 1 mentioned above. However, when the user's weight is applied with the backrest tilted backward, the main body tends to tilt backward due to the expansion and contraction of the telescopic member. Therefore, if weight is suddenly applied backward, there is a risk of tipping over backward. Furthermore, even if it does not tip over, the ease with which it tilts backward can evoke a fear of falling in the user's mind.

[0005] This invention proposes a wheelchair that is less likely to tip over backward even when the user's weight is applied to the backrest, and that has excellent stability. [Means for solving the problem]

[0006] The present invention is a wheelchair characterized by comprising: a base frame portion that supports a seat portion and a backrest portion; a pair of left and right front wheels disposed at the front of the base frame portion; a pair of left and right tilting frame portions that are provided on the support portion of the base frame portion located behind the rear end of the seat portion so as to be tiltable in the vertical direction, and each portion has a front projection portion that protrudes forward from the support portion and a rear projection portion that protrudes backward from the support portion integrally formed thereon; a pair of left and right main wheels disposed on the front projection portions of the left and right tilting frame portions, respectively; a pair of left and right auxiliary wheels disposed on the rear projection portions of the left and right tilting frame portions, respectively; and a tilting frame biasing means for biasing the rear projection portions of the tilting frame portions downward.

[0007] In this configuration, the tilting frame section, which has main wheels and auxiliary wheels at the front and rear, is tiltably supported at the support portion of the base frame section, so that the weight of the user seated on the seat can be supported by the main wheels and auxiliary wheels. Furthermore, since the support portion is located at the rear of the seat, even when weight is applied to the rear of the seat (in other words, when the center of gravity is shifted to the rear of the seat), the main wheels and auxiliary wheels can support the user via the tilting frame section, making it difficult to tip over backward. Moreover, in this configuration, the auxiliary wheels are biased downward by the tilting frame biasing means, making it even more difficult to tip over backward even when weight is applied to the rear of the seat.

[0008] In the conventional configuration described above (the configuration in Patent Document 1), the large wheel support frame is positioned almost vertically directly below the seat, so the user's weight is supported by the main wheels. When weight is shifted backward, the main body tilts around the axis of the main wheels, causing the front wheels to easily lift and the chair to tip over backward.

[0009] As described above, the structure of the present invention offers excellent stability because it is difficult to tip over backward even when weight is shifted to the rear of the seat. This suppresses the fear of tipping over backward that the user may experience, allowing the user to confidently shift their weight backward.

[0010] Furthermore, in the configuration of the present invention, a tilting frame section, on which the main wheels and auxiliary wheels are arranged, is tiltably mounted on the base frame section. Therefore, the tilting frame section and the base frame section tilt relative to each other according to the road surface being traveled on, and the front wheels, main wheels, and auxiliary wheels move in accordance with the road surface. Because of this excellent road-following ability of the front wheels, main wheels, and auxiliary wheels, the front wheels, main wheels, and auxiliary wheels can follow the road surface, even when crossing obstacles or steps, or when entering or exiting slopes, allowing for stable driving. Moreover, this excellent road-following ability is exhibited equally well in both forward and reverse driving, enabling stable driving in both directions.

[0011] In the wheelchair of the present invention described above, the tilting frame biasing means is composed of an expandable and retractable spring member, one end of the spring member is attached to the base frame so as to be rotatable in the vertical direction, and the other end of the spring member is attached to the rear projection of the tilting frame via a connecting mechanism, and the connecting mechanism is proposed to connect the other end of the spring member and the rear projection so as to be rotatable relative to each other in the vertical direction and so as to be movable along the projection direction of the rear projection with a predetermined width.

[0012] Here, for example, in the case where the spring member is only rotatably attached to the rear projection (a configuration without a connecting mechanism), the maximum amount of tilt that the tilting frame can tilt backward (in other words, the lowest position to which the auxiliary wheels can be lowered) is determined by the specifications of the spring member (such as the maximum extension amount) and the balance between the elastic force of the spring member and the weight of the tilting frame (including the main wheels and auxiliary wheels). Therefore, if the auxiliary wheels are lowered to a step deeper than the lowest position of the auxiliary wheels at this maximum tilt, the auxiliary wheels will not be able to make contact with the bottom of the step. This makes it difficult to stably cross the step, especially when the wheelchair is moving backward.

[0013] In the present invention, the other end of the spring member and the rear projection are connected by a connecting mechanism, allowing the other end of the spring member and the rear projection to move relative to each other along the projection direction of the rear projection. Therefore, the auxiliary wheels can be lowered beyond the lower limit position set by the spring member. In other words, even when crossing a step deeper than the lower limit position of the auxiliary wheels, the auxiliary wheels can make contact with the bottom of the step, allowing the wheelchair to travel stably over the step when moving backward.

[0014] In the wheelchair of the present invention described above, a brake unit is provided which can be operated to change position between a braking position in which it is pressed against the main wheel to apply the brakes and a non-braking position in which it is separated from the main wheel, wherein the brake unit is fixed to the front projection of the tilting frame and tilts integrally with the tilting frame.

[0015] In this configuration, the brake unit that applies the brakes to the main wheels is provided to tilt integrally with the tilting frame unit. Therefore, regardless of the tilt of the tilting frame unit, the relative positional relationship between the brake unit and the main wheels can be kept constant. Consequently, with this configuration, the main wheels can always be braked stably by changing the position of the brake unit to the braking position. [Effects of the Invention]

[0016] According to the wheelchair of the present invention, even when a user sitting on the seat applies weight backward, it is difficult to fall backward, and the fear of falling backward can be suppressed from being recalled by the user. In addition, when the tilting frame portion tilts according to the road surface, the front wheels, the main wheels, and the auxiliary wheels move following the road surface, so that it has excellent road surface following performance and can travel stably on various road surfaces.

Brief Description of the Drawings

[0017] [Figure 1] It is a side view of the wheelchair 1 of this embodiment. [Figure 2] It is an explanatory view showing a mode of tilting the rocking frame portion 12 of the wheelchair 1. [Figure 3] (A) It is a side view showing the tilting guide portion 40 and the guided portion 48 of the tilting frame portion 41, and (B) it is a plan view showing a part of the tilting frame portion 41. [Figure 4] It is an explanatory view showing a state where the front wheel 4 has climbed onto the step 103 when the wheelchair 1 moves forward. [Figure 5] It is an explanatory view showing a state where the auxiliary wheel 5 has descended from the step 105 when the wheelchair 1 moves backward. [Figure 6] It is an explanatory view showing a state where the auxiliary wheel 5 has descended from the step 109 when the wheelchair 1 moves backward.

Modes for Carrying Out the Invention

[0018] An embodiment embodying the wheelchair according to the present invention will be described in detail below. As shown in FIG. 1, the wheelchair 1 of this embodiment has a configuration in which a pair of main wheels 3, front wheels 4, and auxiliary wheels 5 are provided on each side, and is a so-called six-wheel type. The wheelchair 1 includes a main body frame 2 made of a metal pipe or a FRP pipe. The main body frame 2 includes a base frame portion 11 that supports the left and right main wheels 3, and a rocking frame portion 12 having a seat portion 6 and a backrest portion 7, and the rocking frame portion 12 is provided on the base frame portion 11 so as to be swingable in the front-rear direction.

[0019] The base frame part 11 is composed of a pair of left and right base side frame parts 14, and the left and right base side frame parts 14 are opposed to each other via the swing frame part 12 disposed therebetween. The base side frame part 14 includes a first base frame part 15 in the front-rear direction, a second base frame part 16 provided below the first base frame part 15, and a front side base frame part 17 to which a front wheel 4 is rotatably attached at the lower end. The front side base frame part 17 is fixed and integrated with the first base frame part 15 and the second base frame part 16. Incidentally, a tilting frame part 41 is provided between the first base frame part 15 and the second base frame part 16, and a main wheel 3 and an auxiliary wheel 5 are provided on the tilting frame part 41. Since this tilting frame part 41 relates to the main part of the present invention, details will be described later.

[0020] As shown in FIGS. 1 and 2, the swing frame part 12 includes a pair of left and right side frame parts 21 and a cross frame part 22 that connects the left and right side frame parts 21. The side frame part 21 includes a main frame part 24, a seat frame part 25 in the front-rear direction attached to the main frame part 24, a backrest frame part 26 in the vertical direction attached to the rear part of the main frame part 24, and a foot frame part 27 attached to the front part of the main frame part 24. A cloth seating seat member (not shown) is provided on the left and right seat frame parts 25, and the seating part 6 is constituted by the seating seat member and the left and right seat frame parts 25. A cloth backrest seat member (not shown) is provided on the left and right backrest frame parts 26, and the backrest part 7 is constituted by the backrest seat member and the left and right backrest frame parts 26. Operation handles 9 operated by an assistant are respectively attached to the upper end parts of the left and right backrest frame parts 26.

[0021] Furthermore, armrest parts 29 are respectively provided on the left and right main frame parts 24. Footrest parts 28 are respectively attached to the left and right foot frame parts 27.

[0022] As described above, the wheelchair 1 of this embodiment has a swinging frame 12 supported on the base frame 11 so as to be able to swing in the front-rear direction, and is equipped with a tilt operation assist member 30 that stabilizes the swinging of the swinging frame 12 and holds it in any position (posture). As a result, as shown in Figure 2, the seat 6 and backrest 7 can be tilted together by tilting the swinging frame 12 relative to the base frame 11. Since such a tilt operation structure can be achieved using conventionally known configurations, a detailed explanation will be omitted.

[0023] The essential parts of the present invention will be described below. As shown in Figure 1, the left and right base side frame sections 14 that constitute the base frame section 11 are each fitted with vertically tilting support sections 31 that span the rear of the first base frame section 15 and the rear of the second base frame section 16, respectively, and the tilting frame section 41 is provided on the left and right tilting support sections 31 via tilting shafts 32 so as to be able to tilt in the vertical direction. The tilting support sections 31 are arranged such that at least the tilting shafts 32 are located behind the rear end of the seat section 6 of the swinging frame section 12, and are fixed to the base side frame section 14.

[0024] The tilting frame section 41 is rod-shaped and extends in the front-rear direction. The main wheel 3 is rotatably supported at the front end of the tilting frame section 41, and the auxiliary wheel 5 is swivelably attached to the rear end of the tilting frame section 41. The tilting frame section 41 is tiltably attached to the tilting support section 31 in the section between the main wheel 3 and the auxiliary wheel 5. When the tilting frame section 41 is divided into a front rod section 42 that protrudes forward and a rear rod section 43 that protrudes backward, with the section attached to the tilting support section 31 as the boundary, the main wheel 3 is supported by the front rod section 42, and the auxiliary wheel 5 is attached to the rear rod section 43. Furthermore, since the tilting frame portion 41 is an integrated unit consisting of a front rod portion 42 and a rear rod portion 43, it tilts vertically around the tilting axis 32, causing the front rod portion 42 and the rear rod portion 43 to operate like a seesaw.

[0025] A gas spring 34 is attached to the rear rod portion 43 of the tilting frame portion 41, biasing it downward relative to the base side frame portion 14 (base frame portion 11). One end of the gas spring 34 is rotatably connected to the first base frame portion 15, and the other end is connected to the rear rod portion 43 via a connecting portion 45, generating an elastic force that extends toward the other end. The connecting portion 45 is disposed between the tilting shaft 32 and the auxiliary wheel 5, and has an elongated hole 46 along the longitudinal direction of the rear rod portion 43 (tilting frame portion 41). The other end of the gas spring 34 is provided with a connecting shaft portion 35 that is rotatably and longitudinally movable through the elongated hole 46 of the connecting portion 45, and is connected to the connecting portion 45 when the connecting shaft portion 35 is inserted through the elongated hole 46. In this way, the other end of the gas spring 34 is connected to the rear rod portion 43 via the connecting portion 45, so that the other end of the gas spring 34 is rotatable relative to the rear rod portion 43 and movable along the elongated hole 46 (within the range of the elongated hole 46's width). Note that a conventionally known gas spring 34 can be used, so details are omitted.

[0026] A parking brake device 37 is attached to the front rod portion 42 of the tilting frame portion 41 via a brake mounting rod portion 36. The parking brake device 37 comprises an operating portion 38 operated by the user, etc., and a brake portion 39 whose position is changed by the operation of the operating portion 38. The brake portion 39 is changed by the operation of the operating portion 38 between a braking position (not shown) in contact with the main wheel 3 and a non-braking position (see Figures 1 and 4-6) separated from the main wheel 3, and when set to the braking position, it applies the brakes to the main wheel 3. Since such a parking brake device 37 can be configured using a conventionally known configuration, a detailed explanation is omitted.

[0027] The parking brake device 37 is fixed to the brake mounting rod 36, and the brake mounting rod 36 is fixed to the front rod 42 of the tilting frame 41. As a result, the parking brake device 37 and the brake mounting rod 36 tilt integrally with the tilting frame 41 (see Figures 4-6). This ensures that the relative positional relationship between the parking brake device 37 and the main wheel 3 remains constant regardless of the tilting of the tilting frame 41. Therefore, the brake unit 39 can always be repositioned stably by operating the operating unit 38, and the main wheel 3 can be stably braked.

[0028] Furthermore, the base side frame portion 14 is provided with a tilting guide portion 40 formed in an arc shape centered on the tilting axis 32 of the tilting support portion 31, in front of the tilting support portion 31. On the other hand, the front rod portion 42 of the tilting frame portion 41 has a roughly U-shaped guided portion 48 at its front end, as shown in Figure 3, which is guided by the tilting guide portion 40. By fitting this guided portion 48 so as to be movable along the tilting support portion 31, the tilting frame portion 41 can tilt more stably in the vertical direction around the tilting axis 32 of the tilting support portion 31. And, because the guided portion 48 and the tilting guide portion 40 prevent the tilting frame portion 41 from shifting in the left-right direction, it is possible to suppress the formation of camber angle and toe angle on the main wheel 3.

[0029] Next, we will explain the driving characteristics of wheelchair 1 as described above. As shown in Figure 1, the wheelchair 1 of this embodiment can travel stably on a flat surface 101 because the front wheels 4, main wheels 3, and auxiliary wheels 5 all make contact with the ground.

[0030] Furthermore, for example, when moving the wheelchair 1 forward to reach a raised area 102 connected to a flat area 101 via a step 103, as shown in Figure 4, first, only the front wheels 4 reach the step 103 and then the wheelchair reaches the raised area 102. At this point, the base frame section 11 and the swing frame section 12 assume a posture in which the front side is tilted upward relative to the tilt frame section 41 (rearward tilt posture), and the main wheels 3 and auxiliary wheels 5 make contact with the flat area 101. This is because the tilt frame section 41 tilts relatively due to the weight (such as the user's weight) applied to the tilt support section 31 connecting the tilt frame section 41 and the base frame section 11, so that the main wheels 3 and auxiliary wheels 5 make contact with the flat area 101. Here, the tilt frame section 41 is stabilized in a state where the main wheels 3 and auxiliary wheels 5 are in contact with the flat area 101 by the biasing force of the gas spring 34. In this reclined position, the user seated on the seat 6 leans backward, and the user's weight is shifted backward. However, this weight is supported by the main wheels 3 and auxiliary wheels 5 via the tilting support section 31 located behind the seat 6, thus providing stability. In particular, since the auxiliary wheels 5 are in contact with the flat ground 101 due to the biasing force of the gas spring 34, the user's weight can be supported even more stably together with the main wheels 3, and the wheelchair 1 is less likely to tip over backward.

[0031] After this, when the main wheel 3 rides onto the step 103 and onto the elevated ground 102 (see Figure 5), the tilting frame section 41 tilts backward due to the biasing force of the gas spring 34, causing the main wheel 3 to make contact with the elevated ground 102 and the auxiliary wheel 5 to make contact with the flat ground 101. At this point, the main wheel 3 and the auxiliary wheel 5 are each made contact with the ground by the biasing force of the gas spring 34, and the user's weight can be stably supported by the main wheel 3 and the auxiliary wheel 5 via the tilting support section 31, and the vehicle becomes less likely to tip over backward.

[0032] On the other hand, for example, when the wheelchair 1 is moved backward down from a flat area 101 to a low area 104 connected by a step 105, as shown in Figure 5, when only the auxiliary wheels 5 first touch the low area 104, the tilting frame section 41 tilts backward due to the biasing force of the gas spring 34, so that the main wheels 3 touch the flat area 101 and the auxiliary wheels 5 touch the low area 104. In this state, the user's weight can be stably supported by the main wheels 3 and auxiliary wheels 5 via the tilting support section 31, and because the auxiliary wheels 5 are in contact with the low area 104 due to the biasing force of the gas spring 34, it is difficult for the wheelchair to tip over backward.

[0033] After this, when the main wheel 3 descends the step 105 and lands on the low ground 104 (see Figure 4), the tilting frame section 41 tilts to eliminate the backward tilt, and the main wheel 3 and auxiliary wheel 5 make contact with the low ground 104. In this state, although the base frame section 11 and the swinging frame section 12 are in a backward tilted position, the user's weight can be stably supported by the main wheel 3 and auxiliary wheel 5 via the tilting support section 31, and the device becomes less likely to tip over backward.

[0034] Furthermore, when the wheelchair 1 is reversed to descend a lower ground 108 with a greater height difference compared to Figure 5, the auxiliary wheels 5 descend and make contact with the lower ground 108, as shown in Figure 6. Here, the gas spring 34 has a defined limit to its extension (product specification). Therefore, when descending a step 109 where the auxiliary wheels 5 cannot make contact with the ground due to the extension limit of the gas spring 34, the connecting shaft portion 35 provided on the gas spring 34 moves within the elongated hole 46 of the connecting portion 45 of the tilting frame portion 41, allowing the tilting frame portion 41 to tilt further backward, and enabling the auxiliary wheels 5 to make contact with the lower ground 108. In this way, when reversing down a relatively large step 109, the tilting frame portion 41 tilts more than the backward tilt position at the extension limit of the gas spring 34, allowing the main wheels 3 to make contact with the flat ground 101 while the auxiliary wheels 5 make contact with the lower ground 108. This allows the user's weight to be stably supported by the main wheels 3 and auxiliary wheels 5 via the tilting support section 31, making it difficult to tip over backward. Furthermore, after this, the main wheels 3 can descend the step 109 and move backward, similar to the reverse movement described above (in the case of low ground 104).

[0035] In the wheelchair 1 of this embodiment, as described above, the tilting frame 41 is tiltably mounted on the base frame 11 by a tilting support 31 located behind the rear end of the seat 6. Therefore, the weight of the user seated on the seat 6 can be supported by the main wheels 3 and auxiliary wheels 5 via the tilting support 31. Furthermore, even when the user leans backward, this weight can be supported by the main wheels 3 and auxiliary wheels 5 via the tilting support 31, making it difficult to tip over backward. This is because the tilting support 31, on which the center of gravity acts, is located behind the seat 6, so even when the user leans backward, they can be stably supported by the main wheels 3 and auxiliary wheels 5. Moreover, in this embodiment, the auxiliary wheels 5 are biased downward by a gas spring 34 interposed between the base frame 11 and the tilting frame 41, making it even more difficult to tip over backward. As a result, even when the seat 6 and backrest 7 are tilted, it is less likely to tip over backward, providing the user with a sense of security.

[0036] As described above, in this wheelchair 1, whether moving forward to climb onto a step or backward to descend a step, the biasing force of the gas spring 34 causes the tilting frame 41 to tilt according to the step, stably bringing the main wheels 3 and auxiliary wheels 5 into contact with the ground. This allows for stable support of the user and makes it difficult to tip backward, allowing the user to move with peace of mind. Furthermore, in the configuration of this embodiment, the gas spring 34 and the rear rod 43 of the tilting frame 41 are rotatably connected by the connecting shaft 35 and the connecting part 45 so as to be movable along the tilting frame 41. Therefore, the tilting frame 41 can be tilted beyond the tilting position at the extension limit of the gas spring 34, allowing the auxiliary wheels 5 to contact the ground even when descending relatively large steps. As a result, when moving backward to descend a relatively large step, the main wheels 3 and auxiliary wheels 5 can be stably brought into contact with the ground, allowing for stable support of the user while moving backward. As described above, the wheelchair 1 of this embodiment has excellent ability to follow various road surface conditions and high driving stability because the front wheels 4, main wheels 3, and auxiliary wheels 5 move in accordance with the road surface.

[0037] Furthermore, in this embodiment, the wheelchair 1 has a parking brake device 37 that applies the brakes to the main wheels 3 fixed to the tilting frame 41. Therefore, regardless of the tilting of the tilting frame 41, the relative positional relationship between the parking brake device 37 and the main wheels 3 remains constant. As a result, even when the tilting frame 41 is tilted to follow the road surface, the brakes to the main wheels 3 can be applied stably by operating the parking brake device 37.

[0038] In the configuration of this embodiment, the portion where the tilting shaft 32 of the tilting support portion 31, which tiltably supports the tilting frame portion 41, is provided corresponds to the support portion according to the present invention. The front rod portion 42 of the embodiment corresponds to the front projection portion according to the present invention, and the rear rod portion 43 of the embodiment corresponds to the rear projection portion according to the present invention. The longitudinal direction of the rear rod portion 43 (tilting frame portion 41) corresponds to the projection direction of the rear projection portion according to the present invention. The gas spring 34 of the embodiment corresponds to the tilting frame biasing means (and spring member) according to the present invention. The connecting mechanism portion according to the present invention is composed of a connecting shaft portion 35 provided at the other end of the gas spring 34 and a connecting portion 45 provided on the tilting frame portion 41.

[0039] The present invention is not limited to the embodiments described above, and can be modified as appropriate without departing from the spirit of the invention. For example, the dimensions and shapes of each part in the embodiments described above can be changed as appropriate.

[0040] In the embodiment, the wheelchair is configured with a tilt function, but it is not limited to this, and may be configured without the tilt function. In addition to the tilt function, it may also be configured with a reclining function that tilts the backrest forward and backward relative to the seat. Furthermore, it may be configured without a tilt function but with a reclining mechanism. In such a configuration with a reclining mechanism, when the backrest is tilted backward, it can be made less likely to tip backward even if the user's weight is shifted backward, and the same effects as in the embodiment can be achieved.

[0041] In the embodiment, the tilting support portion and the portion to which the tilting frame portion is tiltably attached can be appropriately changed and set along the longitudinal direction of the tilting frame portion. Here, it is preferable that the setting of the portion in the tilting frame portion is set considering the balance of weight distribution between the main wheel and the auxiliary wheel. [Explanation of Symbols]

[0042] 1,101 wheelchairs 2. Main frame 3 Main wheels 4 Front wheels 5 Training wheels 6 Seat 7. Backrest 9. Operating handle 11. Base frame section 12. Swiveling frame section 14. Base side frame section 15. First base frame section 16. Second base frame section 17 Front base frame section 21 Side frame section 22 Cross frame section 24 Main frame section 25 Seat frame section 26 Backrest frame section 27 Foot frame section 28 Footrest section 29 Armrest 30 Tilt operation assist member 31 Tilt support part 32 Tilt axis 34. Gas spring (tilting frame biasing means) 35 Connecting shaft part 36 Brake mounting rod 37 Parking brake system 38 Control section 39 Brake section 40 Tilt guide 41. Tilting frame section 42 Front rod (front protrusion) 43 Posterior rod (posterior protrusion) 45 Connecting parts 46 long holes 48 Internal Cases 101 Flat Ground 102 Highland 103,105,109 step difference 104,108 Lowlands

Claims

1. A base frame that supports the seat and backrest, A pair of left and right front wheels are arranged at the front of the base frame section, A pair of left and right tiltable frame portions are provided on the support portion located behind the rear end of the seat portion of the base frame portion, so as to be tiltable in the vertical direction, and each portion has a front projection that protrudes forward from the support portion and a rear projection that protrudes backward from the support portion, which are integrally formed. A pair of left and right main wheels are provided on the front protrusions of the left and right tilting frame sections, A pair of auxiliary wheels are provided on the rear protrusions of the left and right tilting frame sections, A tilt frame biasing means that biases the rear projection of the tilt frame downward. In the base frame portion, a pair of left and right tilting guide portions are formed in an arc shape centered on the tilting axis of the tilting frame portion, in front of the support portion of the tilting frame portion. At the front end of the front projection of the left and right tilting frame portions, there is a guided portion formed in a substantially U-shape that is guided by the tilting guide portion, A wheelchair characterized by being equipped with [a certain feature].

2. The tilt frame biasing means is, It is composed of an expandable and retractable spring member, one end of the spring member is rotatably attached to the base frame portion with respect to the left-right axis, and the other end of the spring member is attached to the rear projection portion of the tilting frame portion via a connecting mechanism. The aforementioned coupling mechanism is The wheelchair according to claim 1, characterized in that the other end of the spring member is rotatably connected to the rear projection about the left-right axis, and is also movably connected along the projection direction of the rear projection with a predetermined width.

3. It is equipped with a brake unit that can be operated to change position between a braking position in which it is pressed against the main wheel to apply the brakes and a non-braking position in which it is separated from the main wheel, The aforementioned brake unit, The wheelchair according to claim 1 or 2, characterized in that it is fixed to the front projection of the tilting frame and tilts integrally with the tilting frame.

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