A wheelchair with adjustable crawler angles

Abstract

A wheelchair according to one embodiment of the present invention comprises a frame having a frame axis and a seat plate mounted thereon, a pair of crawler parts rotatably connected relative to the frame axis, a first tilting part having one end rotatably connected relative to the frame and the other end rotatably connected relative to the pair of crawler parts, a first motor part for driving the pair of crawler parts, and a control part for controlling the first motor part, wherein each of the pair of crawler parts comprises a rear crawler, an intermediate crawler rotatable relative to the rear crawler, and a front crawler rotatable relative to the intermediate crawler, and the wheelchair further comprises a second tilting part for rotating the intermediate crawler relative to the rear crawler and the front crawler.

Description

Technology Field

[0001] The present invention relates to a wheelchair capable of adjusting the angle of the crawler. Background Technology

[0002] The wheelchair industry is achieving continuous growth and technological advancements driven by the progress of an aging society and increasing interest in mobility for people with disabilities. For instance, technological developments are taking place in various fields, including electric wheelchairs equipped with autonomous driving capabilities, power assist systems that add electric functions to manual wheelchairs, and wheelchairs that enhance mobility and portability through the use of lightweight materials and foldable designs. These trends contribute to improving the quality of life and enhancing mobility for wheelchair users, and technological innovation and market growth are expected to continue in the future.

[0003] From this perspective, wheelchair technology capable of ascending and descending stairs has recently been making various advancements to enhance user convenience and safety.

[0004] FIGS. 1 and 2 illustrate a conventional wheelchair disclosed in Korean Registered Patent Publication No. 10-2366931 as an example of a conventional wheelchair capable of ascending and descending stairs. For reference, FIGS. 1 and 2 correspond to FIGS. 4 and FIGS. 7 of the aforementioned Korean Registered Patent Publication, respectively. For convenience of explanation, the reference numerals used in the aforementioned Korean Registered Patent Publication have been used as they are without modification, and even if these reference numerals overlap with the reference numerals used in the description of the present invention below, they do not refer to the same components.

[0005] A conventional wheelchair includes a frame (100), a crawler section, and a tilting drive section (300).

[0006] The crawler section includes a first crawler (210) with one end rotatably coupled to one side of the frame, and a second crawler (220) connected to the other end of the first crawler (210) and positioned such that the driving surface is spaced upward from the first crawler (210) with respect to the driving surface of the first crawler (210). The first crawler (210) and the second crawler (220) are positioned in the forward and backward directions of the driving direction.

[0007] One side of the tilting drive unit (300) is connected to the frame (100) and the other side is connected to the crawler unit, and the tilting angle of the crawler unit is adjusted according to operation.

[0008] However, conventional wheelchairs with the above-described configuration had a problem in that the angle formed by the first crawler (210) and the second crawler (220) constituting the crawler section could not be adjusted to be unfolded in a straight line or folded at a predetermined angle as desired by the user, resulting in poor ride comfort when going up and down stairs.

[0009] In addition, as the left and right crawler sections are lifted and lowered as a whole depending on the extension and shortening of the tilting drive unit (300), it was difficult to keep the seat plate parallel to the horizontal plane depending on the slope and curvature of the driving surface. Prior art literature

[0010] Korean Patent Publication No. 10-2647202 (Publication Date: March 13, 2024) The problem to be solved

[0011] The present invention aims to solve the problems of the prior art as described above. The objective of the present invention is to provide a wheelchair that maintains good ride comfort for the occupant during ascent and descent of stairs, as well as when driving on inclined and curved surfaces, by adjusting the angles between a plurality of partial crawlers (front, middle, and rear crawlers) constituting the crawler. means of solving the problem

[0012] To achieve the above objective, a wheelchair according to one embodiment of the present invention comprises a frame having a frame axis mounted on a seat plate, a pair of crawler parts rotatably connected relative to the frame axis, a first tilting part having one end rotatably connected relative to the frame and the other end rotatably connected relative to the pair of crawler parts, a first motor part driving the pair of crawler parts, and a control part controlling the first motor part, wherein each of the pair of crawler parts comprises a rear crawler, an intermediate crawler rotatable relative to the rear crawler, and a front crawler rotatable relative to the intermediate crawler, and the wheelchair further comprises a second tilting part that rotates the intermediate crawler relative to the rear crawler and the front crawler.

[0013] In addition, the rear crawler comprises a first rear crawler pulley that rotates by the first motor unit and a second rear crawler pulley that rotates in conjunction with the first rear crawler pulley; the intermediate crawler comprises a first intermediate crawler pulley that rotates in conjunction with the second rear crawler pulley and a second intermediate crawler pulley that rotates in conjunction with the first intermediate crawler pulley; and the front crawler comprises a first front crawler pulley that rotates in conjunction with the second intermediate crawler pulley and a second front crawler pulley that rotates in conjunction with the first front crawler pulley.

[0014] Additionally, the rear crawler further comprises a rear link, one end of which is connected to the shaft of the first rear crawler pulley and the other end of which is connected to the shaft of the first intermediate crawler pulley; the intermediate crawler further comprises an intermediate link, one end of which is connected to the shaft of the first intermediate crawler pulley and the other end of which is connected to the shaft of the second intermediate crawler pulley; and the front crawler further comprises a front link, one end of which is connected to the shaft of the second intermediate crawler pulley and the other end of which is connected to the shaft of the second front crawler pulley.

[0015] In addition, the second rear crawler pulley and the first intermediate crawler pulley are linked by a first chain, and the second intermediate crawler pulley and the first front crawler pulley are linked by a second chain.

[0016] In addition, the second tilting unit is characterized by including a second motor unit and a power transmission member that receives power from the second motor unit to rotate the intermediate link relative to the rear link and rotate the front link relative to the intermediate link.

[0017] In addition, the power transmission member is characterized by comprising: a sub-link connected to the intermediate link and rotating in conjunction with it; a drive gear that rotates by the second motor unit; a first gear that is gear-coupled to the drive gear and fixed to the intermediate link; a second gear that is gear-coupled to the drive gear and connected to the sub-link so as to be rotatable relative to the sub-link; a third gear that rotates in conjunction with the rotation of the second gear; and a fourth gear that is fixed to the front link and rotates by the third gear.

[0018] In addition, the second gear and the third gear are characterized by being linked by a third chain.

[0019] In addition, the above driving gear, the above first gear, and the above second gear are characterized as being bevel gears.

[0020] In addition, the rotation direction of the first gear and the rotation direction of the fourth gear are opposite.

[0021] In addition, the first rear crawler pulley and the second rear crawler pulley are connected by a rear crawler belt, the first intermediate crawler pulley and the second intermediate crawler pulley are connected by an intermediate crawler belt, and the first front crawler pulley and the second front crawler pulley are connected by a front crawler belt.

[0022] In addition, the first motor unit is characterized by including two first servo motors that drive each of the pair of crawler units.

[0023] In addition, the sub-link connecting shaft connecting the pair of crawler parts is rotatably connected to the second gear, and the other end of the first tilting part is rotatably connected to the sub-link connecting shaft.

[0024] In addition, the first tilting part comprises a left first tilting part that tilts the left crawler part of the pair of crawler parts and a right first tilting part that tilts the right crawler part, wherein a left sub-link connecting shaft is connected to the left crawler part of the pair of crawler parts and a right sub-link connecting shaft is connected to the right crawler part, wherein the left first tilting part is connected to the left sub-link connecting shaft and the right first tilting part is connected to the right sub-link connecting shaft.

[0025] In addition, the wheelchair is characterized by further including a seat angle measuring sensor that detects the angle at which the seat is tilted relative to the horizontal plane.

[0026] In addition, the wheelchair is characterized by further including a tilt angle measuring sensor that detects the tilted angle of the longitudinal central axis of the frame relative to the direction of travel.

[0027] The above method of controlling the wheelchair is characterized by including a step in which, when the seat angle measuring sensor detects that the seat of the wheelchair is tilted relative to the horizontal plane during ascent or descent, the control unit controls the first tilting unit to level the seat.

[0028] In addition, as a method for controlling the wheelchair, when the tilt angle measuring sensor detects that the wheelchair is tilted relative to the direction of travel during ascent or descent of stairs, the control unit controls the first motor unit to increase the speed of one of the pair of crawler units to align the longitudinal center axis of the wheelchair with the direction of travel. Effects of the invention

[0029] A wheelchair according to an embodiment of the present invention having the above-described configuration has the following effects.

[0030] The angle of rotation between the crawler components, namely the front crawler, middle crawler, and rear crawler, can be adjusted, so that no separate preparation step is required when entering or exiting stairs, and the height of the seat can be minimized during ascent / descent, thereby providing comfort to the rider.

[0031] In addition, by adjusting the angle of the N-shaped crawler, the N-shaped folded form can be utilized when entering stairs to eliminate the need for auxiliary wheels for entering stairs, and the N-shaped folded crawler can be changed into a straight form while climbing stairs to improve the riding sensation during climbing.

[0032] In addition, the seat angle can be automatically adjusted parallel to the horizontal plane according to the angle of the stairs through the control unit, and the direction of travel of the wheelchair can also be automatically adjusted in the same direction as the direction of travel of the stairs, thereby helping the occupant to safely ascend and descend the stairs.

[0033] In addition, through the control unit, the left and right crawler sections can be individually raised or lowered even when driving on inclined or curved surfaces, thereby enabling good ride comfort for the occupant depending on the driving surface environment.

[0034] Meanwhile, the present invention also includes other effects that can be expected from the above-described configuration, although not explicitly stated. Brief explanation of the drawing

[0035] Figure 1 shows the crawler section and tilting drive section of a conventional wheelchair. Figure 2 shows the process of climbing stairs using the wheelchair of Figure 1. FIG. 3 shows a wheelchair according to one embodiment of the present invention, FIG. 3 (a) is a perspective view (the seat plate is omitted from the drawing) and FIG. 3 (b) is a side view. Figure 4 is a rear view of the wheelchair of Figure 3. Figure 5(a) shows the crawler section of the wheelchair of Figure 3 folded into an N shape, and Figure 5(b) shows the crawler section unfolded into a straight line. Fig. 6 is a perspective view of the main components of the right crawler section of the wheelchair of Fig. 3. Figure 7 is a view of the right crawler section of Figure 6 from the opposite side. Figure 8 is a plan view of the main configuration of the right crawler section of Figure 6. FIG. 9 shows the crawler section and the first tilting section of the wheelchair of FIG. 3 in an unfolded state. FIG. 10 shows the crawler section and the first tilting section of the wheelchair of FIG. 3 when the crawler section is folded into an N shape. FIG. 11 shows a modified example of the sub-link connecting shaft of FIG. 10, in which the sub-link connecting shaft is separated into a left sub-link connecting shaft and a right sub-link connecting shaft. Fig. 12 is an enlarged view of part F of Fig. 9. Figure 13 is an enlarged view of section G of Figure 10. FIG. 14 (a) is a side view showing the wheelchair of FIG. 3 with the seat tilted relative to the horizontal plane while climbing stairs, and FIG. 14 (b) is a top view showing the wheelchair tilted relative to the direction of travel. FIG. 15 is a diagram illustrating the action of the wheelchair of FIG. 3 in correcting the tilted state of the seat plate. FIG. 16 is a diagram illustrating the action of correcting the tilted state of the wheelchair of FIG. 3 relative to the driving direction. FIG. 17 is a diagram for explaining the operation of the wheelchair of FIG. 3, where FIG. 17 (a) shows the state when traveling on a flat surface, FIG. 17 (b) shows the state when starting to climb stairs, and FIG. 17 (c) shows the state while climbing stairs. Figure 18 shows a modified example of Figure 11 in which the left crawler section and the right crawler section are rotated separately. Specific details for implementing the invention

[0036] Hereinafter, embodiments of the present invention are described in detail with reference to the attached drawings so that those skilled in the art can implement them. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein. Furthermore, in describing the embodiments of the present invention, descriptions of known components of the wheelchair are omitted or simplified in order to avoid losing sight of the main point of the invention. For reference, the terms left, right, front, and rear in this specification refer to the user's left, right, front, and rear, respectively, based on the user being seated on the seat. For example, in FIG. 5, the left side of the drawing refers to the front and the right side of the drawing refers to the rear, and among the pair of crawler parts shown in FIG. 9, the left side of the drawing corresponds to the right crawler part and the right side of the drawing corresponds to the left crawler part.

[0037] FIG. 3 illustrates a schematic diagram of a wheelchair with an adjustable crawler angle according to one embodiment of the present invention. For reference, the seat on which the user sits is omitted from the illustration and, based on FIG. 3 (b), can be fixed on the frame (1) parallel to the ground. For reference, reference numeral 400 indicates the main wheel and 410 indicates the caster.

[0038] As illustrated in FIGS. 3, 4, 8, etc., a wheelchair capable of adjusting the angle of a crawler according to one embodiment of the present invention (hereinafter simply referred to as "wheelchair") comprises a frame (1) having a frame axis (11) and a seat plate (500) mounted thereon, a pair of crawler sections (2) rotatably connected relative to the frame axis (11), a first tilting section (3) having one end rotatably connected relative to the frame (1) and the other end rotatably connected relative to the pair of crawler sections (2), a first motor section (5) for driving the pair of crawler sections (2), and a control section (not shown) for controlling the first motor section (5). Meanwhile, in this embodiment, reference numeral 2-1 indicates the right crawler section, and reference numeral 2-2 indicates the left crawler section.

[0039] In the wheelchair of the present invention, each of the pair of crawler sections (2) is characterized by including a rear crawler (21), an intermediate crawler (22) rotatable relative to the rear crawler (21), and a front crawler (23) rotatable relative to the intermediate crawler (22). For reference, FIG. 5 (a) shows the crawlers (21, 22, 23) folded together in an approximately N shape, and FIG. 5 (b) shows the crawlers unfolded into a straight line.

[0040] As illustrated in FIGS. 6 and 8, the rear crawler (21) is equipped with a first rear crawler pulley (211) that rotates by a first motor unit (5) and a second rear crawler pulley (212) that rotates in conjunction with the first rear crawler pulley (211).

[0041] The intermediate crawler (22) is equipped with a first intermediate crawler pulley (221) that rotates in conjunction with the second rear crawler pulley (212), and a second intermediate crawler pulley (222) that rotates in conjunction with the first intermediate crawler pulley (221).

[0042] The front crawler (23) is equipped with a first front crawler pulley (231) that rotates in conjunction with the second intermediate crawler pulley (222), and a second front crawler pulley (232) that rotates in conjunction with the first front crawler pulley (231).

[0043] Here, the first rear crawler pulley (211) and the second rear crawler pulley (212) are connected by a rear crawler belt (213), the first intermediate crawler pulley (221) and the second intermediate crawler pulley (222) are connected by an intermediate crawler belt (223), and the first front crawler pulley (231) and the second front crawler pulley (232) are connected by a front crawler belt (233).

[0044] The rear crawler (21) is equipped with a rear link (214), wherein one end of the rear link (214) is rotatably connected relative to the axis (C1) of the first rear crawler pulley (211), and the other end is rotatably connected relative to the axis (C2) of the first intermediate crawler pulley (221).

[0045] The intermediate crawler (22) is provided with an intermediate link (224), wherein one end of the intermediate link (224) is rotatably connected relative to the axis (C2) of the first intermediate crawler pulley (221), and the other end is rotatably connected relative to the axis (C3) of the second intermediate crawler pulley (222).

[0046] The front crawler (23) is equipped with a front link (234), the front link (234) having one end connected to the shaft (C3) of the second intermediate crawler pulley (222) and the other end connected to the shaft (C4) of the second front crawler pulley (232).

[0047] For example, the second rear crawler pulley (212) and the first intermediate crawler pulley (221) can be connected by the first chain (61), and the second intermediate crawler pulley (222) and the first front crawler pulley (231) can be connected by the second chain (62) (see FIG. 8).

[0048] The first motor unit (5) may be composed of two first sub-motors (5-1, 5-2) that drive each of the pair of crawlers (2).

[0049] The first tilting part (3) may be a linear motor, a linear actuator, etc., whose length can be extended or shortened.

[0050] Referring to FIGS. 9, 10, and 12, a second tilting part (4) is provided to rotate the intermediate crawler (22) relative to the rear crawler (21) and the front crawler (23).

[0051] The second tilting section (4) is equipped with a second motor section (41) and a power transmission member (42). The second motor section (41) is equipped with a second servo motor (41-1, 41-2) which is respectively provided in the left and right crawler sections.

[0052] The second motor part (41) transmits power to the power transmission member (42).

[0053] Referring to FIG. 12, the power transmission member (42) receives power from the second motor unit (41) and rotates the intermediate link (224) relative to the rear link (214) (U direction), and also rotates the front link (233) relative to the intermediate link (224) (L direction).

[0054] For example, the power transmission member (42) is equipped with a sub-link (424), a driving gear (421), a first gear (422), a second gear (423), a third gear (425), and a fourth gear (426).

[0055] The sub-link (424) is connected to the intermediate link (224) and rotates in conjunction with it.

[0056] The drive gear (421) is rotated by the second motor part (41).

[0057] The first gear (422) is gear-coupled to the drive gear (421) and fixed to the intermediate link (224).

[0058] The second gear (423) is gear-coupled to the drive gear (421) and is rotatably connected to the sub-link (424).

[0059] The third gear (425) rotates in conjunction with the rotation of the second gear (423). The third gear (425) may be composed of two sub-gears (425-1, 425-2) that mesh with each other and rotate in opposite directions.

[0060] The fourth gear (426) is fixed to the front link (234) and rotates by the third gear (425).

[0061] Here, the driving gear (421), the first gear (driven gear) (422), and the second gear (driven gear) (423) may be bevel gears. And the second gear (423) and the third gear (425) may, for example, be connected by a third chain (427).

[0062] Through the above configuration, the rotational direction of the first gear (422) and the rotational direction of the fourth gear (426) are opposite to each other, and thus, when the intermediate link (224) rotates upward (U direction), the front link (234) rotates downward (L direction).

[0063] Meanwhile, as shown in FIGS. 10 and 12, a sub-link connecting shaft (24) connecting a pair of crawler sections (2) to each other is rotatably connected to a second gear (423). The other end of the first tilting section (3) is rotatably connected to the sub-link connecting shaft (24). In this case, the pair of crawler sections (2) are simultaneously lifted or lowered by the extension and shortening of the first tilting section (3).

[0064] FIG. 11 illustrates a modified example of a sub-link connecting shaft (24). That is, the right sub-link connecting shaft (24-1) and the left sub-link connecting shaft (24-2) are separated from each other so that a pair of crawler sections (2) are not connected to each other.

[0065] The right first tilting part (31) is connected to the right sub-link connecting shaft (24-1), and the left first tilting part (32) is connected to the left sub-link connecting shaft (24-2). Through this, as shown in FIG. 18, the left and right crawler parts (2) can be lifted or lowered separately, thereby improving the user's ride comfort even on sloped or curved driving surfaces.

[0066] Meanwhile, the wheelchair of the present invention includes a seat angle measuring sensor (not shown) that detects the angle (θ1) (see (a) of FIG. 14) at which the seat plate (500) is tilted relative to the horizontal plane.

[0067] In addition, the wheelchair of the present invention includes a tilt angle measuring sensor (not shown) that detects the tilted angle (θ1) of the longitudinal central axis (E) of the wheelchair relative to the direction of travel (D) (see (b) of FIG. 14).

[0069] The operation of a wheelchair according to one embodiment of the present invention having the above-described configuration will be explained below.

[0070] First, the process of transitioning from a crawler section folded into an N shape as shown in FIG. 5 (a) to a crawler section unfolded into a straight shape as shown in FIG. 5 (b) will be explained.

[0071] Referring to FIG. 11 and FIG. 13, etc., when the second motor unit (41) is operated to rotate the drive gear (421), the first gear (422) rotates in the R1 direction and rotates the intermediate link (224) relative to the rear link (214) in the direction of relative unfolding (L direction).

[0072] At this time, the second gear (423) rotates in the opposite direction, that is, in the R2 direction, and the sub-gear (425-1) rotates in the R2 direction in conjunction with this by the third chain (427), and the sub-gear (425-2) engaged with the sub-gear (425-1) rotates in the opposite direction, in the R1 direction, and finally, as the fourth gear (426) rotates in the R2 direction, the front link (234) fixed to and linked to the fourth gear (426) rotates relatively in the direction (U direction) that spreads out relative to the intermediate link (224).

[0073] Through the process described above, the rear crawler (21), the middle crawler (22), and the front crawler (23) are spread out together, and the crawler section (2) is in an unfolded state.

[0074] Conversely, to switch from a state where the rear crawler (21), intermediate crawler (22), and front crawler (23) are spread out (Fig. 5 (b)) to a state where the crawler section (2) is folded into an N shape (Fig. 5 (a)), the second motor section (41) is driven to rotate the drive gear (421) in the opposite direction.

[0075] According to the above operation, as illustrated in FIG. 17, the wheelchair of the present invention can improve ride comfort during ascent by adjusting the angle of the N-shaped crawler to enter the stairs (see FIG. 17 (b)) and then ascending the stairs with the N-shaped folded crawler unfolded into a straight line (see FIG. 17 (c)). For reference, FIG. 17 (a) shows the wheelchair of the present invention during flat driving.

[0076] Meanwhile, as illustrated in FIG. 15, when the seat angle measuring sensor detects that the seat of the wheelchair is tilted relative to the horizontal plane (θ1) during the ascent and descent of stairs, the control unit can adjust the horizontal level of the seat by extending or shortening the first tilting part (3).

[0077] For example, as shown in FIG. 15 (b), when the wheelchair is tilted to the right (based on FIG. 15), the length of the first tilting part (linear motor) (3) is reduced so that the frame (1) is rotated relative to the crawler part (2) with respect to the frame axis (11) (i.e., the frame is rotated counterclockwise around the frame axis (11)), thereby leveling the seat plate as shown in FIG. 15 (a).

[0078] Conversely, as shown in (c) of FIG. 15, when the wheelchair is tilted to the left (based on FIG. 15), the length of the linear motor (3) is increased so that the frame (1) is rotated relative to the crawler part (2) with respect to the frame axis (11) (i.e., the frame is rotated clockwise around the frame axis (11)), thereby leveling the seat plate as shown in (a) of FIG. 15.

[0079] Additionally, as shown in FIG. 16, when the tilt angle measuring sensor detects that the wheelchair is tilted (θ2) relative to the direction of travel (D) during stair ascent and descent, the control unit controls the first motor unit (5) to increase the speed of the crawler unit (2) located in the tilted direction among the pair of crawler units (2), thereby aligning the longitudinal center axis (E) of the wheelchair with the direction of travel (D). For reference, in FIG. 16, the top is the stair ascent direction and the bottom is the stair descent direction.

[0080] For example, as shown in (b) of FIG. 16, when the wheelchair is tilted to the left (based on FIG. 16), the speed of the right crawler (2-1) of the pair of crawler parts (2) can be increased to align the longitudinal center axis (E) of the wheelchair with the direction of travel (D).

[0081] Although preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present invention as defined in the following claims also fall within the scope of the present invention.

Claims

Claim 1 A wheelchair comprising a frame having a frame axis and a seat plate mounted thereon, a pair of crawler sections rotatably connected relative to the frame axis, a first tilting section having one end rotatably connected relative to the frame and the other end rotatably connected relative to the pair of crawler sections, a first motor section driving the pair of crawler sections, and a control section controlling the first motor section, wherein each of the pair of crawler sections includes a rear crawler, an intermediate crawler rotatable relative to the rear crawler, and a front crawler rotatable relative to the intermediate crawler, and the wheelchair further includes a second tilting section that rotates the intermediate crawler relative to the rear crawler and the front crawler, wherein the rear crawler includes a first rear crawler pulley that rotates by the first motor section and a second rear crawler pulley that rotates in conjunction with the first rear crawler pulley, and the intermediate crawler includes a first rear crawler pulley that rotates in conjunction with the second rear crawler pulley The apparatus includes an intermediate crawler pulley and a second intermediate crawler pulley that rotates in conjunction with the first intermediate crawler pulley, and the front crawler includes a first front crawler pulley that rotates in conjunction with the second intermediate crawler pulley and a second front crawler pulley that rotates in conjunction with the first front crawler pulley, and the rear crawler further includes a rear link, one end of which is connected to the shaft of the first rear crawler pulley and the other end of which is connected to the shaft of the first intermediate crawler pulley, and the intermediate crawler further includes an intermediate link, one end of which is connected to the shaft of the first intermediate crawler pulley and the other end of which is connected to the shaft of the second intermediate crawler pulley, and the front crawler further includes a front link, one end of which is connected to the shaft of the second intermediate crawler pulley and the other end of which is connected to the shaft of the second front crawler pulley, and the second tilting unit comprises a second motor unit, andA wheelchair capable of angle adjustment of a crawler, characterized by including a power transmission member that receives power from the second motor unit and rotates the intermediate link relative to the rear link and rotates the front link relative to the intermediate link. Claim 2 delete Claim 3 delete Claim 4 A wheelchair capable of adjusting the angle of a crawler, characterized in that, in claim 1, the second rear crawler pulley and the first intermediate crawler pulley are linked by a first chain, and the second intermediate crawler pulley and the first front crawler pulley are linked by a second chain. Claim 5 delete Claim 6 A wheelchair capable of adjusting the angle of a crawler according to claim 1, wherein the power transmission member comprises: a sub-link connected to the intermediate link and rotating in conjunction with it; a drive gear that rotates by the second motor unit; a first gear that is gear-coupled to the drive gear and fixed to the intermediate link; a second gear that is gear-coupled to the drive gear and connected to the sub-link so as to be rotatable relative to the sub-link; a third gear that rotates in conjunction with the rotation of the second gear; and a fourth gear that is fixed to the front link and rotates by the third gear. Claim 7 A wheelchair with adjustable crawler angle, characterized in that, in claim 6, the second gear and the third gear are linked by a third chain. Claim 8 A wheelchair capable of adjusting the angle of a crawler, characterized in that, in claim 7, the drive gear, the first gear, and the second gear are bevel gears. Claim 9 A wheelchair capable of adjusting the angle of a crawler, characterized in that, in claim 6, the rotational direction of the first gear and the rotational direction of the fourth gear are opposite to each other. Claim 10 A wheelchair capable of adjusting the angle of a crawler, characterized in that, in claim 1, the first rear crawler pulley and the second rear crawler pulley are linked by a rear crawler belt, the first intermediate crawler pulley and the second intermediate crawler pulley are linked by an intermediate crawler belt, and the first front crawler pulley and the second front crawler pulley are linked by a front crawler belt. Claim 11 A wheelchair capable of adjusting the angle of a crawler, characterized in that, in claim 1, the first motor unit comprises two first servo motors that drive each of the pair of crawler units. Claim 12 A wheelchair capable of adjusting the angle of a crawler, characterized in that, in claim 6, a sub-link connecting shaft connecting the pair of crawler parts is rotatably connected to the second gear, and the other end of the first tilting part is rotatably connected to the sub-link connecting shaft. Claim 13 A wheelchair capable of adjusting the angle of a crawler, characterized in that, in claim 6, the first tilting part comprises a left first tilting part that tilts the left crawler part of the pair of crawler parts and a right first tilting part that tilts the right crawler part, and a left sub-link connecting shaft is connected to the left crawler part of the pair of crawler parts and a right sub-link connecting shaft is connected to the right crawler part, the left first tilting part is connected to the left sub-link connecting shaft and the right first tilting part is connected to the right sub-link connecting shaft. Claim 14 A wheelchair capable of angle adjustment of a crawler according to claim 1, characterized in that the wheelchair further includes a seat angle measuring sensor that detects the angle at which the seat is tilted relative to a horizontal plane. Claim 15 A wheelchair capable of angle adjustment of a crawler according to claim 11, characterized in that the wheelchair further includes a tilt angle measuring sensor that detects the tilted angle of the longitudinal central axis of the wheelchair relative to the direction of travel. Claim 16 A method for controlling a wheelchair according to claim 14, wherein when the seat angle measuring sensor detects that the seat of the wheelchair is tilted relative to a horizontal plane during ascent or descent, the control unit includes the step of controlling the first tilting unit to level the seat. Claim 17 A method for controlling a wheelchair according to claim 15, wherein when the tilt angle measuring sensor detects that the wheelchair is tilted relative to the direction of travel during ascent or descent of stairs, the control unit controls the first motor unit to increase the speed of the crawler unit located in the tilted direction among the pair of crawler units so as to align the longitudinal center axis of the wheelchair with the direction of travel.

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