Auxiliary wheel mechanism and transport equipment equipped therewith

Abstract

To provide an auxiliary wheel mechanism that allows for smooth and easy operation of extending and retracting auxiliary wheels used when maneuvering to narrow spaces or overcoming steps, and lifting transport equipment, as well as transport equipment equipped with the same. [Solution] The auxiliary wheel mechanism 1 of the present invention comprises a mounting member 9 that can be attached to transport equipment, a parallel link mechanism 21 attached to the mounting member 9, and an auxiliary wheel 24 attached to the parallel link mechanism 21. With this configuration, the auxiliary wheel 24 can be extended and retracted, and the transport equipment can be lifted and released with simple operation through the action of the parallel link mechanism 21. Furthermore, by providing a temporary fixing means that automatically prevents the parallel link mechanism 21 from rotating when the parallel link mechanism 21 rotates to move the auxiliary wheel 24 by a predetermined amount, it is easy to keep the transport equipment in a lifted state, etc.

Description

Technical Field

[0002] , ,

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[0001] The present invention relates to an auxiliary wheel mechanism that facilitates width adjustment and step-over of a transport device, and a transport device equipped with this auxiliary wheel mechanism.

Background Art

[0002] In transport devices such as wheelchairs used for transporting people and carts used for transporting goods, at least some wheels (for a cart, the two rear wheels on the side of the push handle; for a wheelchair, the two rear wheels called drive wheels) are straight-aiding wheels with the rotation direction fixed in a certain direction in order to ensure straight-aiding stability. And, in order to ensure maneuverability, the remaining wheels (for a cart, the two front wheels; for a wheelchair, the two front wheels called casters) are configured as maneuvering wheels whose rotation direction can be freely changed, such as swivel casters. Therefore, for example, when it is desired to align a wheelchair or cart along a wall or when it is desired to align a wheelchair along a bed, etc., i.e., when so-called width adjustment is desired, it is necessary to switch back and forth many times, which is inconvenient. In response to such problems, wheelchairs and carts equipped with an auxiliary wheel mechanism shown in Patent Documents 1 to 3 have been proposed in order to facilitate width adjustment of these transport devices.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] Patent Document 1 does not show a specific configuration for raising or lowering either the manual turning wheel or the auxiliary wheel of a wheelchair, making it difficult to raise or lower either the manual turning wheel or the auxiliary wheel while a person is seated. Furthermore, in the wheelchair of Patent Document 2, an auxiliary wheel support member and a guide member for linearly moving the second auxiliary wheel up and down are connected to a link mechanism that rotates to apply the lever principle. As a result, an oblique force acts on the guide member that guides the up and down movement of the auxiliary wheel support member, causing sticking and galling, making it impossible to smoothly move the second auxiliary wheel up and down or lift the transport equipment. Moreover, in the trolley of Patent Document 3, after pressing down the foot lever to lift the fixed wheels of the trolley and lower the lateral movement wheels, the lateral movement wheels must be fixed so that they do not rise, and the foot lever must be released, which is a time-consuming process. [Means for solving the problem]

[0005] This invention was created in view of the above problems, and aims to provide an auxiliary wheel mechanism and a transport device equipped therewith that enable smooth and easy operation of extending and retracting auxiliary wheels used when maneuvering to maneuver over obstacles or steps, and lifting the transport device. To achieve this objective, the auxiliary wheel mechanism of this invention is characterized by comprising a mounting member that can be attached to the transport device, a parallel link mechanism attached to the mounting member, and an auxiliary wheel attached to the parallel link mechanism. With this configuration, the auxiliary wheel can be moved in parallel by the action of the parallel link mechanism to make contact with the running surface or to move away from the running surface, so that the auxiliary wheel can be smoothly extended and retracted with simple operation. In addition, the lifting and releasing of the transport device can also be performed smoothly with simple operation by the action of the parallel link mechanism.

[0006] In the auxiliary wheel mechanism, the parallel link mechanism is preferably configured such that, when the mounting member is attached to the transport equipment, a pair of parallel links are arranged so as to extend perpendicularly to the running surface of the auxiliary wheel, one of these links is connected to the mounting member, and the other link is configured to reciprocate vertically relative to the first link while maintaining the vertical position, and the auxiliary wheel is attached to the other link. This configuration ensures that the axis of rotation of the auxiliary wheel remains parallel to the running surface as it moves, preventing it from tilting or making contact with the ground at an angle.

[0007] Furthermore, it is desirable that the auxiliary wheel mechanism includes an intercepting engagement member that intercepts between the parallel link mechanism and the mounting member in response to the rotation of the other link of the parallel link mechanism, thereby preventing the parallel link mechanism from returning to its original position. With this configuration, the parallel link mechanism can be automatically prevented from returning to its original position when the auxiliary wheel makes contact with the running surface and the transport equipment is lifted, and the parallel link mechanism can be kept in that rotated state.

[0008] In the auxiliary wheel mechanism provided with the aforementioned interlocking engagement member, it is desirable to provide a release means that retracts the interlocking engagement member from its interlocking position between the parallel link mechanism and the mounting member, thereby returning the parallel link mechanism to a rotatable state. Providing such a release means makes it easy to return the auxiliary wheels to their original position by rotating the parallel link mechanism and release the lifted state of the transport equipment.

[0009] In the configuration of the auxiliary wheel mechanism described above, it is desirable that the auxiliary wheels be capable of rotating in a direction different from the direction of rotation of the straight-moving wheels of the transport equipment equipped with straight-moving wheels. This makes it possible to move the transport equipment in small increments in a direction different from the direction of rotation of the straight-moving wheels when the transport equipment is lifted by the operation of the parallel link mechanism and supported and moved by the auxiliary wheels.

[0010] Furthermore, it is desirable that the auxiliary wheel mechanism be equipped with a temporary locking means that automatically locks the parallel link mechanism so that it cannot rotate when the parallel link mechanism rotates to move the auxiliary wheel by a predetermined amount. With this configuration, it is possible to automatically disable the parallel link mechanism when the auxiliary wheel makes contact with the running surface and the transport equipment is lifted, and to keep the parallel link mechanism in the same rotating state.

[0011] In the configuration of the auxiliary wheel mechanism equipped with the temporary fixing means described above, it is desirable to provide a release means that allows the parallel link mechanism, which has become immobile due to the temporary fixing means, to become rotatable again. By providing such a release means, it becomes easy to return the auxiliary wheels to their original position and release the lifted state of the transport equipment.

[0012] Even in the configuration of the auxiliary wheel mechanism that includes the aforementioned temporary fixing and release means, it is desirable that the auxiliary wheels be capable of rotating in a direction different from the direction of rotation of the straight-line wheels of the transport equipment equipped with straight-line wheels. This makes it possible to move the transport equipment in small increments in a direction different from the direction of rotation of the straight-line wheels when the transport equipment is lifted by the operation of the parallel link mechanism and supported and moved by the auxiliary wheels.

[0013] Furthermore, in order to achieve the above objective, the present invention provides a transport device having a straight-travel wheel whose rotation direction is fixed in a certain direction and a swivel wheel whose rotation direction can be freely changed, characterized in that it comprises a parallel link mechanism that can rotate to lift the straight-travel wheel off the running surface, and an auxiliary wheel attached to the parallel link mechanism that can make contact with the running surface by the rotation of the parallel link mechanism. With a transport device configured in this way, the auxiliary wheel can be moved in parallel by the operation of the parallel link mechanism to make contact with the running surface or lift off the running surface, so that the auxiliary wheel can be smoothly extended and retracted with simple operation. In addition, the straight-travel wheel of the transport device can be lifted and released with simple operation by the operation of the parallel link mechanism. Therefore, it becomes possible to easily and smoothly perform maneuvers such as moving the transport device to the side.

[0014] In the aforementioned transport device, the parallel link mechanism is preferably configured such that a pair of parallel links are arranged so as to extend perpendicularly to the running surface of the auxiliary wheel, one of these links is integrally connected to the transport device, and the other link is configured to reciprocate vertically while maintaining the vertical orientation relative to the first link, with the auxiliary wheel attached to the other link. With this configuration, the auxiliary wheel moves vertically with its axis of rotation parallel to the running surface, so that when the auxiliary wheel touches the ground, it does not touch the ground at an angle.

[0015] Furthermore, it is desirable that the transport equipment be equipped with an intercepting engagement member that intercepts between the parallel link mechanism and its mounting portion in response to the rotation of the other link of the parallel link mechanism, thereby preventing the parallel link mechanism from returning to its original position. With this configuration, the parallel link mechanism can be automatically prevented from returning to its original position when the auxiliary wheels make contact with the running surface and the transport equipment is lifted, and the parallel link mechanism can be kept in that rotated state.

[0016] In a transport device equipped with the aforementioned interlocking engagement member, it is desirable to have a release mechanism that retracts the interlocking engagement member from its interlocking position between the parallel link mechanism and the mounting portion, thereby returning the parallel link mechanism to a rotatable state. By providing such a release mechanism, it becomes easy to return the auxiliary wheels to their original position by rotating the parallel link mechanism and release the lifted state of the transport device.

[0017] In the configuration of the transport equipment described above, it is desirable that the auxiliary wheels be capable of rotating in a direction different from the rotation direction of the straight-moving wheels. This makes it possible to move the transport equipment in small increments in a direction different from the rotation direction of the straight-moving wheels when the transport equipment is lifted by the operation of the parallel link mechanism and supported and moved by the auxiliary wheels.

[0018] Furthermore, it is desirable that the transport equipment be equipped with a temporary locking mechanism that automatically locks the parallel link mechanism in a non-rotatable state when the parallel link mechanism rotates to move the auxiliary wheels by a predetermined amount. With this configuration, the parallel link mechanism can be automatically made non-rotatable when the auxiliary wheels make contact with the running surface and the transport equipment is lifted, and the parallel link mechanism can be kept in the rotated state.

[0019] In the configuration of the transport equipment equipped with the temporary fixing means described above, it is desirable to have a release means that allows the parallel link mechanism, which has become immobile due to the temporary fixing means, to become rotatable again. By providing such a release means, it becomes easy to return the auxiliary wheels to their original position and release the lifted state of the transport equipment.

[0020] Even in the configuration of transport equipment that includes the aforementioned temporary fixing and release means, it is desirable that the auxiliary wheels be capable of rotating in a direction different from the rotation direction of the straight-moving wheels. This makes it possible to move the transport equipment in small increments in a direction different from the rotation direction of the straight-moving wheels when the transport equipment is lifted by the operation of the parallel link mechanism and supported and moved by the auxiliary wheels. [Effects of the Invention]

[0021] According to the auxiliary wheel mechanism of the present invention and the transport device provided with the same, the auxiliary wheel can be smoothly grounded on or lifted from the running surface with a simple operation by the action of the parallel link mechanism. Further, by the action of the parallel link mechanism, the wheels of the transport device can be smoothly lifted and the lifting can be released with a simple operation. Furthermore, by making the parallel link mechanism non-rotatable by means of an interruption engagement member or a temporary fixing means, it becomes possible to keep the wheels of the transport device lifted without continuously applying a force to rotate the parallel link mechanism. Therefore, it becomes possible to ground the auxiliary wheel while floating the wheels of the transport device, and to easily and smoothly perform operations such as aligning the width of the transport device and crossing a step. Further, when the auxiliary wheel is taken in and out, since the auxiliary wheel can be translated by the translational movement of the link of the parallel link mechanism, it is possible to provide a mechanism for preventing an operation in which an unreasonable force is applied to the auxiliary wheel, such as grounding the rolling surface of the auxiliary wheel obliquely.

[0022] In addition, since it is provided with a release means for returning the parallel link mechanism, which has been made non-rotatable by the temporary fixing means, to a rotatable state, when it is desired to ground the wheels of the transport device, etc., the parallel link mechanism can be made rotatable promptly to store the auxiliary wheel.

Brief Description of the Drawings

[0023] [Figure 1] It is a left side view showing a part of the auxiliary wheel mechanism according to the present invention in cross section. [Figure 2] It is a right side view showing a part of the auxiliary wheel mechanism according to the present invention in cross section. [Figure 3] It is a plan view showing a part of the auxiliary wheel mechanism according to the present invention with a notch. [Figure 4] It is a front view showing a part of the auxiliary wheel mechanism according to the present invention with a notch. [Figure 5] It is a rear view showing a part of the auxiliary wheel mechanism according to the present invention with a notch. [Figure 6] It is a partially cutaway cross-sectional view taken along line A-A of FIG. 1. [Figure 7] It is a partially cutaway cross-sectional view taken along line B-B of FIG. 4. [Figure 8]Figure 4 is a partially cutaway cross-sectional view illustrating the operation of the BB line. [Figure 9] This is a rear view of a wheelchair equipped with an auxiliary wheel mechanism according to the present invention. [Figure 10] Figure 9 is a cross-sectional view relating to the CC line. [Figure 11] This is a partially cutaway cross-sectional view illustrating the operation of a wheelchair equipped with the auxiliary wheel mechanism according to the present invention. [Figure 12] This is a partially cutaway cross-sectional view illustrating the operation of a wheelchair equipped with the auxiliary wheel mechanism according to the present invention. [Figure 13] This is a partially cutaway cross-sectional view illustrating the operation of a wheelchair equipped with the auxiliary wheel mechanism according to the present invention. [Figure 14] This is a partially cutaway plan view illustrating the operation of a wheelchair equipped with an auxiliary wheel mechanism according to the present invention. [Figure 15] This is a partially cutaway front view illustrating the operation of a wheelchair equipped with an auxiliary wheel mechanism according to the present invention. [Figure 16] This is a partially cutaway cross-sectional view illustrating the operation of a wheelchair equipped with the auxiliary wheel mechanism according to the present invention. [Figure 17] This is a partially cutaway cross-sectional view of a trolley equipped with an auxiliary wheel mechanism according to the present invention. [Modes for carrying out the invention]

[0024] The following describes embodiments for carrying out the invention. In Figures 1 to 8, reference numeral 1 indicates one embodiment of the auxiliary wheel mechanism according to the present invention. This auxiliary wheel mechanism 1 is used by being attached to transport equipment used for transporting people and goods, such as a wheelchair 2 or a trolley 3, and here we will introduce one that is attached to a wheelchair 2 in particular. Figures 9 and 10 show the auxiliary wheel mechanism 1 attached to a wheelchair 2.

[0025] Wheelchair 2 is constructed by stretching fabric over a foldable pipe frame 4 to form the seat 5 and backrest 6, and by attaching front wheels 7,7 and rear wheels 8,8 to the pipe frame 4. The front wheels 7,7 are swivel wheels that can freely change direction (direction of rotation) 360° around the mounting point on the pipe frame 4, similar to so-called swivel casters, while the rear wheels 8,8 are straight-line wheels whose direction of rotation is fixed to a certain direction that moves the wheelchair 2 forward and backward.

[0026] The auxiliary wheel mechanism 1 has mounting members 9 that are attached across the ends of pipe frames 4 that extend to the inside of each rear wheel 8, 8 on both sides below the seat 5 of the wheelchair 2. These mounting members 9 are made by bending aluminum alloy or steel plates, and U-shaped insertion guide portions 9a are formed at both ends of the mounting member 9, through which the ends of the pipe frame 4 can be inserted. Hand-tightened bolts 9b are screwed into these insertion guide portions 9a, and the mounting member 9 can be fixed to the pipe frame 4 by inserting the ends of the pipe frame into the insertion guide portions 9a and tightening the pipe frame 4 with the bolts 9b. The rear part of the mounting member 9 is a rear wall 9c that is bent upwards to a predetermined length and at a right angle.

[0027] A front link 10 is fixed to the center of the lower surface of the mounting member 9. This front link 10 is made by bending an aluminum alloy plate or a steel plate, and consists of a front wall portion 10a and side walls 10b, 10b formed by bending both sides of the front wall portion 10a at a right angle to the rear. The upper end of this front link 10 is welded to the lower surface of the mounting member 9, so that the front wall portion 10a and the side walls 10b, 10b are positioned to hang downward from the mounting member 9.

[0028] A driven link 11 and a driving link 12 are rotatably supported and connected to both side walls 10b, 10b of the front link 10. These driven links 11 and driving links 12 extend rearward and are rotatably supported and connected to the rear link 13.

[0029] The driven link 11 is made by bending a steel plate into a U-shape, and its side walls 11a, 11a are rotatably supported on the upper parts of the side walls 10b, 10b of the front link 10 and the upper parts of the side walls 13b, 13b (details to be described later) of the rear link 13. The shaft 14 that supports the driven link 11 and the rear link 13 is configured to be rotatably inserted through both links 11 and 13, and a plate-shaped lock panel 15 extending upward is integrally and rotatably fixed to this shaft 14. This lock panel 15 extends behind the mounting member 9 and is constantly biased toward the mounting member 9 by a spring 16. A cam follower 17 is also rotatably mounted on the front surface of this lock panel 15, and the cam follower 17 receives the bias of the lock panel 15 by the spring 16 and constantly has its rolling surface in contact with the rear wall 9c of the mounting member 9. Furthermore, a release pedal 18 for rotating the lock panel 15 backward is integrally connected to it.

[0030] The drive link 12 is configured such that a hollow link pipe 12a is positioned extending in the front-rear direction of the auxiliary wheel mechanism 1, and this link pipe 12a is rotatably supported at the lower parts of the side walls 10b, 10b of the front link 10 and the lower parts of the side walls 13b, 13b (details to be described later) of the rear link 13. The rear end of this link pipe 12a protrudes further back than the rear link 13, and the main pedal 19 is rotatably supported at this rear end. As shown in Figure 8, the main pedal 19 is normally kept in an upward-rotated state (hereinafter referred to as the retracted state) due to the biasing force of the spring 20. In addition, a stopper member 12b is fixed to the rear end of the link pipe 12a, positioned on the rotation path of the main pedal 19, and contacts when the main pedal 19 rotates downward to a predetermined angle. This stopper member 12b prevents the main pedal 19 from rotating further downward, as it is positioned on the rear extension of the link pipe 12a.

[0031] The rear link 13 consists of a rear wall portion 13a that is always parallel to the front wall portion 10a of the front link 10, side walls 13b, 13b formed by bending both sides of the rear wall portion 13a forward at a right angle, and caster brackets 13c, 13c that are fixed to the side walls 13b, 13b, respectively, protruding laterally.

[0032] The lower central portion of the rear wall 13a is cut out so that the link pipe 12a of the drive link 12 can protrude rearward, and so that even when the link pipe 12a rotates due to the operation of the main pedal 19, sufficient clearance is maintained without interference. In addition, one end of the spring 20 that biases the main pedal 19 is connected to the lower part of this rear wall 13a.

[0033] As described above, the rear end of the driven link 11 is pivotally supported on the upper part of the side walls 13b, 13b of the rear link 13, and the link pipe 12a of the driving link 12 is pivotally supported on the lower part of the side walls 13b, 13b. In this pivoted state, the driven link 11 and the link pipe 12a are always configured to be parallel. Similarly, the front wall portion 10a of the front link 10 and the rear wall portion 13a of the rear link 13 are always configured to be parallel, and these front wall portion 10a and rear wall portion 13a are configured to extend in a direction perpendicular to the running surface F of the wheelchair 2 (which is also the running surface of the auxiliary wheels 24 described later). These front link 10, driven link 11, driving link 12, and rear link 13 constitute a three-dimensional parallel link mechanism 21. Through the operation of this parallel link mechanism 21, the rear link 13 is configured to move up and down while the rear wall portion 13a maintains a vertical position.

[0034] The lower ends of springs 22, 22, one end of which is supported at the upper end of the side walls 10b, 10b of the front link 10, are connected to the lower parts of the side walls 13b, 13b of the rear link 13. These springs 22, 22 bias the parallel link mechanism 21 so that the rear link 13 is always rotated (raised). In addition, a regulating bar 23 is fixed across the side walls 13b, 13b of the rear link 13, which is always located above the rotation path of the link pipe 12a. This regulating bar 23 is configured to be positioned so as the rear link 13 rotates (down) downward or the link pipe 12a rotates relative to the rear link 13, so as the rear link 13 rotates downward or the link pipe 12a rotates relative to the rear link 13, it can contact the link pipe 12a.

[0035] The length L1 from the pivot point of the drive link 12 with the rear link 13 to the tip of the main pedal 19 is set to be longer than the length L2 between the pivot points of the rear link 13 and the front link 10 of the drive link 12, in order to effectively utilize the lever principle described later.

[0036] Auxiliary wheels 24, 24 are integrally mounted on the caster brackets 13c, 13c, projecting downwards and allowing for vertical movement. The wheels 24a of these auxiliary wheels 24 are rotatably supported on a fork 24b, and their rolling surfaces are positioned to roll in contact with the running surface F (ground or floor, etc.) of the wheelchair 2. These auxiliary wheels 24, 24 are so-called swivel casters, and as shown by the dashed lines in Figures 1, 4, and 5, the fork 24b can rotate freely around the mounting part to the caster bracket 13c, thereby allowing the orientation of the wheels 24a to be freely changed 360°. Normally, the parallel link mechanism 21 is biased by a spring 22, so that the rolling surfaces of the wheels 24a are held in a position lifted above the running surface F.

[0037] On the other hand, a plate-shaped release link 25 is pivotally mounted on the upper surface of the mounting member 9 so as to be rotatable within a plane parallel to the upper surface. The front part of this release link 25 is configured as a contact surface 25a that protrudes forward from the mounting member 9 and hangs downward, and this contact surface 25a is always positioned in front of the front wall portion 10a of the front link 10. Furthermore, a release pin 26 is rotatably connected to the rear part of the release link 25, passing through the rear wall 9c of the mounting member 9 and extending toward the lock panel 15. This release pin 26 is slidably inserted through the rear wall 9c of the mounting member 9, and the rear end that protrudes from the rear wall 9c and faces the lock panel 15 is configured as a thin head with a larger diameter than the rest, so as not to come out forward from the rear wall 9c. Furthermore, this release pin 26 is always biased forward by a spring 27, thereby keeping the release pin 26 in constant contact with the rear wall 9c from the rear. Furthermore, due to the biasing force from the spring 27 of the release pin 26, the release link 25 is also constantly biased to a predetermined state, that is, to a state in which the contact surface 25a rotates in a direction that approaches the roller bearing 31, which will be described later.

[0038] The link pipe 12a of the drive link 12 has a hollow cylindrical main body, and its front end protrudes forward from the front link 10. A lever joint 28, made of a hollow cylindrical pipe, is inserted into the front end of this link pipe 12a, and a long pipe-shaped operating lever 29 is inserted into and fixed integrally with this lever joint 28. This operating lever 29 extends to the front lower position of the seat surface 5 of the wheelchair 2, and a resin grip 29a is attached to its tip so that it can be operated by hand by a wheelchair user (hereinafter simply referred to as the user) seated in the wheelchair 2. The outer diameter of the part of this operating lever 29 that is inserted into the lever joint 28 is configured such that the tip is smaller than the inner diameter of the lever joint 28, and then tapers to become larger than the outer diameter of the lever joint 28. Therefore, it can be easily inserted into and fixed into the lever joint 28, and can be easily pulled out and removed when not needed.

[0039] The lever joint 28 is inserted into the link pipe 12a so as to be rotatable around the axis of the link pipe 12a, and a swing rod 30 is fixed to the insertion portion of the lever joint 28, passing through it in the diametrical direction. The swing rod 30 protrudes from both the top and bottom of the link pipe 12a through a hole 12c drilled in the link pipe 12a in the diametrical direction. The upper end of the swing rod 30 is always positioned adjacent to the contact surface 25a, and a roller bearing 31 is rotatably mounted on this upper end with its rolling surface facing the contact surface 25a. The lower end of the swing rod 30 is connected to the front link 10 by a spring 32. The spring 32 constantly biases the swing rod 30 so that the roller bearing 31 is positioned slightly away from the contact surface 25a. Furthermore, the hole 12c is formed to have a diameter sufficiently larger than that of the swing rod 30, and the swing rod 30 is configured to rotate by the amount of the gap between it and the hole 12c.

[0040] The operation of the auxiliary wheel mechanism 1 and the transport equipment equipped therewith will be explained using the operation diagrams in Figures 11 to 16.

[0041] As shown in Figure 8, when the main pedal 19, which is in the retracted position, is rotated toward the running surface F by the foot or hand, the main pedal 19 rotates against the biasing force of the spring 20 to a position where it extends along the extension of the link pipe 12a. When it rotates to this position, the main pedal 19 hits the stopper member 12b and can no longer rotate (hereinafter, this state is referred to as the "used state"). Furthermore, since the spring 20 that biases the main pedal 19 extends from the lower part of the rear wall portion 13a of the rear link 13, which is below the pivot point (rotation pivot point) of the main pedal 19, and is connected to the main pedal 19, once the main pedal 19 has rotated downward to a certain extent, the tension of the spring prevents it from rotating upward. Rather, it works to bias it downward so that the main pedal 19 is kept in the "used state". To return the main pedal 19 to the retracted position, the main pedal 19 should be rotated to an angle where the spring 20 has the effect of rotating the main pedal 19 upward. In this case, the main pedal 19 rotates back to its retracted position due to the force of the spring 20.

[0042] As shown in Figure 11, under normal conditions, the auxiliary wheel mechanism 1 attached to the wheelchair 2 is in a state where the parallel link mechanism 21 rotates due to the biasing force of the spring 22, causing the rear link 13 to rise. As a result, the auxiliary wheels 24, 24 are kept in a position lifted off the running surface F, and the wheelchair 2 is in a state where the front wheels 7 and rear wheels 8 are in contact with the running surface F. In this state, when a caregiver (here, a caregiver refers to a person who stands behind the wheelchair 2 and operates the wheelchair 2 by holding the handles 4a, 4a) presses the main pedal 19, which is in the use state, the driving link 12 and the driven link 11 rotate around the pivot point of the front link 10, and in response, the rear link 13 descends. Along with this, the cam follower 17 rolls downward along the rear wall 9c of the mounting member 9, and the auxiliary wheels 24 descend, causing the wheels 24a to make contact with the running surface F. At this time, due to the action of the parallel link mechanism 21, that is, the driven link 11 rotates while maintaining a state parallel to the driving link 12, the rear link 13 descends while maintaining a vertical position with respect to the running surface F. Therefore, the auxiliary wheels 24, 24 also descend while their axis of rotation is parallel to the running surface F. As a result, the rolling surfaces of the auxiliary wheels 24, 24 do not make contact with the running surface F at an angle, and uneven force is not applied to the auxiliary wheels 24, 24 when they make contact with the ground, which would damage them.

[0043] When the main pedal 19 is pressed further, the lever principle comes into play with the wheel 24a of the auxiliary wheel 24 that is in contact with the ground as the fulcrum, and as shown in Figure 12, the driving link 12 and the driven link 11 rotate around the pivot point of the rear link 13. As a result, the front link 10, the mounting member 9, or the wheelchair 2 is lifted, and the rear wheels 8,8 of the wheelchair 2 are lifted off the running surface F. At this time, due to the action of the parallel link mechanism 21, the front link 10 rises while maintaining a vertical position relative to the running surface F. Therefore, the user seated in the wheelchair 2 hardly feels any movement in the forward and backward direction and does not feel any fear. In addition, in this embodiment, the dimensional ratio L1:L2 between the pivot point of the connection between the front link 10 and the rear link 13 of the driving link 12 and the tip of the main pedal 19 is set so that L1 is sufficiently longer than L2. Furthermore, auxiliary wheels 24, 24 are positioned on the rear link 13, which is on the main pedal 19 side, and the wheelchair 2 is connected to the front link 10 via a mounting member 9. As a result, after the auxiliary wheels 24, 24 touch the ground as the rear link 13 descends, the lever principle comes into play, with the point where the force is applied to the main pedal 19 being the point of effort, the pivot point between the drive link 12 and the rear link 13 being the fulcrum, and the pivot point between the drive link 12 and the front link 10 being the point of application. Therefore, even with a person seated, the caregiver can easily lift the rear wheels 8 of the wheelchair 2 with relatively little force.

[0044] As shown in Figure 12, when the rear wheels 8,8 are lifted by a predetermined amount from the running surface F, the cam follower 17 disengages downward from the rear wall 9c of the mounting member 9. As a result, the lock panel 15 rotates toward the mounting member 9 due to the biasing force of the spring 16, the cam follower 17 engages with the lower surface of the mounting member 9, and the lock panel 15 comes into contact with the rear wall 9c of the mounting member 9 (more precisely, the rear end of the release pin 26 that protrudes slightly from the rear wall 9c). Consequently, the cam follower 17 remains engaged with the lower surface of the mounting member 9, preventing the rear link 13 from rotating upward and the front link 10 from rotating downward. In other words, the parallel link mechanism 21 cannot rotate in a direction that brings the rear wheels 8,8 of the wheelchair 2 to the ground.

[0045] Furthermore, at the stage when the cam follower 17 engages with the lower surface of the mounting member 9, the regulating bar 23 reaches a position close to directly above the link pipe 12a. In other words, the rotation of the drive link 12 up to this point causes the angle of the link pipe 12a to be close to the angle of the regulating bar 23. Therefore, if the link pipe 12a tries to rotate any further in the direction that raises the front link 10, it will hit the regulating bar 23 and will not be able to rotate any further. Thus, the rear link 13 will not be able to rotate in the downward direction, and the front link 10 will not be able to rotate in the upward direction. In other words, the parallel link mechanism 21 will not be able to rotate in the direction that further lifts the rear wheels 8,8 of the wheelchair 2.

[0046] As described above, the cam follower 17 and the regulating bar 23 act as stoppers, preventing the parallel link mechanism 21 (rear link 10) from rotating in either the upward or downward direction. Therefore, even when the force applied to the main pedal 19 is released, the wheelchair 2 remains in a state where the rear wheels 8,8 are lifted off the ground. In this way, by lifting the rear wheels 8,8 off the running surface F, the parallel link mechanism 21 is automatically locked in a non-rotatable state. Therefore, it is no longer necessary to continuously press the main pedal 19 to keep the rear wheels 8,8 lifted, reducing the burden on the caregiver.

[0047] With the rear wheels 8,8 lifted off the ground, the front wheels 7,7 and auxiliary wheels 24,24 of the wheelchair 2 are all configured to allow the rotation direction of wheels 24a,24a to be freely changed, similar to swivel casters. This makes it possible to move the wheelchair 2 precisely in all directions, including forward, backward, left, right, and diagonally. This makes it extremely easy to maneuver the wheelchair 2 in narrow spaces, such as when you want to move it close to a wall in an elevator or alongside a serving counter in a cafeteria. This eliminates the need to repeatedly maneuver the wheelchair 2 in reverse, as was done in the past, to move it closer to a wall.

[0048] To release the parallel link mechanism 21 from its immobile state, the release pedal 18 is pressed. At this time, since the release pedal 18 is integrally configured with the lock panel 15, it rises to an angle that makes it easy to press as the lock panel 15 rotates (see Figure 12). When the release pedal 18 is pressed with the foot, as shown in Figure 13, the lock panel 15 rotates backward against the biasing force of the spring 16, and the cam follower 17 also rolls along the lower surface of the mounting member 9 and disengages from it. As a result, the parallel link mechanism 21 becomes rotatable, and the rear link 10 rises back to its original position due to the biasing force of the springs 22, 22, that is, the position where the auxiliary wheels 24, 24 are lifted off the ground and retracted upward, so that the rear wheels 8, 8 of the wheelchair 2 make contact with the running surface F. At this time, the amount that the rear wheels 8,8 lift off the ground is set to be small (just enough so as not to interfere with the rolling of the auxiliary wheels 24,24), so the impact when the rear wheels 8,8 touch the ground is hardly transmitted to the user seated in wheelchair 2. However, if this is a concern, the caregiver can hold the handles 4a,4a to support wheelchair 2 to some extent and then press the release pedal 18 to easily mitigate the impact on the user. In actual practice, the caregiver will likely hold the handles 4a,4a of wheelchair 2 when pressing the release pedal 18, so the impact on the user will be mitigated without conscious effort.

[0049] Furthermore, as described above, when the rear wheels 8,8 of the wheelchair 2 are lifted and the parallel link mechanism 21 is locked in a non-rotatable state, pressing the main pedal 19 further allows the wheelchair 2 to be supported and operated solely by the auxiliary wheels 24,24. That is, when a caregiver holds the handles 4a,4a to support the wheelchair 2 and presses the main pedal 19 further, the front wheels 7,7 of the wheelchair 2 can also be easily lifted from the running surface F by the lever principle by the desired amount. In this way, with the front wheels 7 and rear wheels 8 of the wheelchair 2 lifted from the running surface F (the entire wheelchair 2 lifted), it is also possible to move the wheelchair 2 forward, backward, etc., using only the auxiliary wheels 24,24. Therefore, when there is a step, by moving the wheelchair until the auxiliary wheels 24,24 are close to the step with the front wheels 7,7 lifted, the small-diameter front wheels 7,7, which would be difficult to overcome the step, can be moved onto the step. As mentioned above, by pressing the release pedal 18 and placing the rear wheels 8,8 on the step, it is possible to overcome the step with the wheelchair 2. In reality, the rear wheels 8,8 often come into contact with the step and ride up when the auxiliary wheels 24,24 are brought closer to the step. In such cases, pressing the release pedal 18 causes the parallel link mechanism 21 to return to its original position (the rear link 13 rises under the biasing force of the springs 22,22), and the auxiliary wheels 24,24 are retracted towards the wheelchair 2. Note that because the rear wheels 8,8 have a large diameter, it is possible to overcome steps that can be overcome by lifting the front wheels 7,7 by rotating the wheelchair itself. Therefore, it is not always necessary to ride up the rear wheels 8,8 onto the step.

[0050] Since a support wheel 19a is provided on the underside of the main pedal 19, when the wheelchair 2 is tilted backward to overcome the aforementioned step and the main pedal 19 approaches the running surface F, this support wheel 19a comes into contact with the running surface F and rolls. As a result, the main pedal 19 does not rub against the running surface F, which increases resistance when operating the wheelchair 2 and prevents the main pedal 19 from being damaged, making it possible to smoothly move the wheelchair 2 and the auxiliary wheel mechanism 1.

[0051] In a wheelchair 2 equipped with this auxiliary wheel mechanism 1, the user of the wheelchair 2 can lift the rear wheels 8,8 while remaining seated on the seat, and then lower the lifted rear wheels 8,8 back down. That is, when the user seated in the wheelchair 2 pulls up the operating lever 29, the parallel link mechanism 21 is activated in the same way as described above from the opposite direction to the main pedal 19, causing the auxiliary wheels 24,24 to touch the running surface F and lifting the rear wheels 8 of the wheelchair 2 off the running surface F. In this case as well, the stopper action of the cam follower 17 and the regulating bar 23 is at work, so even if the user releases their hand from the operating lever 29, the rear wheels 8,8 can be kept lifted. This allows the user to move the wheelchair 2 themselves to maneuver, such as to move it closer to obstacles.

[0052] When the user wants to lower the lifted rear wheels 8,8 to the ground, the user rotates the operating lever 29 in the direction of the dashed arrow in Figure 14. As shown in Figures 14 to 16, the lever joint 28 rotates relative to the link pipe 12a, and the swing rod 30 rotates integrally with the lever joint 28. The swing rod 30 can rotate by the amount of the gap with the hole 12c, and this rotation of the swing rod 30 causes the roller bearing 31 to contact and press against the adjacent contact surface 25a, thereby rotating the release link 25. When the release link 25 rotates, the release pin 26 slides axially against the biasing force of the spring 27 so as to protrude rearward from the rear wall 9c, as shown in Figures 14 and 16, and pushes the lock panel 15, which is in contact with its rear end, causing it to rotate rearward. In other words, the lock panel 15 can be rotated in the same way as when the release pedal 18 is pressed, thereby detaching the cam follower 17 from the lower surface of the mounting member 9, making the parallel link mechanism 21 rotatable and allowing the rear wheels 8,8 to touch the ground. In this way, the user can perform the series of operations on the auxiliary wheel mechanism 1 and wheelchair 2 that were previously performed by the caregiver.

[0053] Furthermore, if there is an assistant who can operate the wheelchair 2, the operating lever 29 may actually get in the way. In such cases, the operating lever 29 can be detached from the lever joint 28 for operation.

[0054] Figure 17 shows an example of attaching the auxiliary wheel mechanism 1 to the trolley 3 by changing the structure of the mounting member 9 of the auxiliary wheel mechanism 1 to a structure that clamps the loading platform 33 of the trolley 3 from above and below. In this example, the trolley 3 is equipped with two fixed wheels 34 for straight movement whose rotation direction is fixed in the front-rear direction at the lower rear of the loading platform 33, and two swivel wheels 35 for turning whose rotation direction can be freely changed at the lower front of the loading platform 33, and the auxiliary wheel mechanism 1 is positioned between the fixed wheels 34. Even when attached to the trolley 3 in this way, as in the case of the wheelchair 2 described above, by pressing the main pedal 19, the fixed wheels 34 of the trolley 3 are lifted up and the auxiliary wheels 24, 24 are brought to the ground, and the trolley 3 can be moved using the auxiliary wheels 24, 24 and the swivel wheels 35. This makes it possible to easily and smoothly perform side-to-side movements, such as moving the trolley 3 in place in a direction perpendicular to the rotation direction of the fixed wheels 34. Furthermore, overcoming steps when the parallel link mechanism 21 is locked in a non-rotatable state can be achieved using the same mechanism as in the case of wheelchair 2 described above. Note that when used with trolley 3, the lever coupling 28, operating lever 29, release link 25, and release pin 26 related structures are unnecessary; therefore, the auxiliary wheel mechanism shown in Figure 17 omits these components.

[0055] In the above explanation, the auxiliary wheels 24 were given as examples of a structure that allows the direction of the wheels to be freely changed 360°, such as a swivel caster. However, for the auxiliary wheels 24, it is also possible to use wheels whose rotation direction is fixed to a certain direction. When using such auxiliary wheels 24 whose rotation direction is fixed to a certain direction, for example, by arranging the auxiliary wheels 24 so that the rotation direction of the wheels is perpendicular to the rotation direction of the rear wheels 8,8 of the wheelchair 2 or the fixed wheels 34 of the trolley 3, an auxiliary wheel mechanism can be provided that allows for easy lateral movement of the wheelchair 2 or trolley 3, that is, movement in a direction perpendicular to the rotation direction of the rear wheels 8 or fixed wheels 34.

[0056] Finally, let's address the consistency with the terminology used in the claims. In this embodiment, the pair of parallel links in the claims correspond to the front link 10 (front wall portion 10a and side wall 10b) and the rear link 13 (rear wall portion 13a and side wall 13b). Also, the intercepting engagement member in the claims is implemented in this embodiment by the lock panel 15 and cam follower 17. Furthermore, the temporary fixing means in the claims is implemented in this embodiment by the lock panel 15, spring 16, cam follower 17, and regulating bar 23. In this case, even without the regulating bar 23, it is possible to make the parallel link mechanism 21 unable to rotate in only one direction. Also, the release means in the claims is implemented in this embodiment by the release pedal 18 or release link 25, release pin 26, spring 27, lever coupling 28, operating lever 29, swing rod 30, roller bearing 31, and spring 32. The release pedal 18 is an example of a release mechanism when operated by a caregiver, while the configuration of the release link 25, release pin 26, spring 27, lever joint 28, operating lever 29, swing rod 30, roller bearing 31, and spring 32 is an example of a release mechanism when operated by a user of the wheelchair 2. [Explanation of symbols]

[0057] 1 Training wheel mechanism 2 Wheelchairs 3 carts 7 Front wheels 8 Rear wheels 9. Mounting components 10 Previous Links 11. Driven link 12. Driving link 13 Rear link 15 Lock Panel 17 Cam Follower 18 Release pedal 19 Main pedal 21 Parallel link mechanism 23 Regulatory Bar 24 Auxiliary wheels 25 Unlock link 26 Release pin 29 Operating lever 30 Swing Rod 31 Roller bearings 34 Fixed wheels 35 Swivel wheel F Running surface

Claims

1. An auxiliary wheel mechanism characterized by comprising a mounting member that can be attached to transport equipment, a parallel link mechanism attached to the mounting member, and an auxiliary wheel attached to the parallel link mechanism.

2. The parallel link mechanism is characterized in that, with the mounting member attached to the transport equipment, a pair of parallel links are arranged so as to extend perpendicularly to the running surface of the auxiliary wheel, one of these links is connected to the mounting member, the other link is configured to reciprocate vertically relative to the first link while maintaining the vertical position, and the auxiliary wheel is attached to the other link.

3. The auxiliary wheel mechanism according to claim 2, further characterized by comprising an intercepting engaging member that intercepts between the parallel link mechanism and the mounting member in response to the rotation of the other link of the parallel link mechanism, thereby preventing the return rotation of the parallel link mechanism.

4. The auxiliary wheel mechanism according to claim 3, further comprising a release means for retracting the intercepting engagement member from the intercepting position between the parallel link mechanism and the mounting member, thereby returning the parallel link mechanism to a rotatable state.

5. The auxiliary wheel mechanism according to any one of claims 1 to 4, characterized in that the auxiliary wheel comprises a wheel that can rotate in a direction different from the direction of rotation of the straight-travel wheel of a transport device equipped with at least a straight-travel wheel.

6. The auxiliary wheel mechanism according to claim 1 or 2, characterized in that it includes a temporary fixing means that automatically locks the parallel link mechanism so that it cannot rotate when the parallel link mechanism rotates to move the auxiliary wheel by a predetermined amount.

7. The auxiliary wheel mechanism according to claim 6, characterized in that it is provided with a release means to return a parallel link mechanism, which has become immobile due to a temporary fixing means, to a rotatable state.

8. The auxiliary wheel mechanism according to claim 6, characterized in that the auxiliary wheel comprises a wheel that can rotate in a direction different from the direction of rotation of the straight-travel wheel of a transport device equipped with at least a straight-travel wheel.

9. The auxiliary wheel mechanism according to claim 7, characterized in that the auxiliary wheel comprises a wheel that can rotate in a direction different from the direction of rotation of the straight-travel wheel of a transport device equipped with at least a straight-travel wheel.

10. In a transport device having a straight-line wheel whose rotation direction is fixed in a certain direction and a swivel wheel whose rotation direction can be freely changed, A transport device characterized by comprising a parallel link mechanism that can rotate to lift the aforementioned straight-running wheels off the running surface, and auxiliary wheels attached to the parallel link mechanism that can make contact with the running surface by the rotation of the parallel link mechanism.

11. The parallel link mechanism is characterized in that a pair of parallel links are arranged to extend perpendicularly to the running surface of the auxiliary wheels, one of these links is integrally connected to the transport equipment, the other link is configured to reciprocate vertically relative to the first link while maintaining the vertical position, and the auxiliary wheels are attached to the other link.

12. The conveying device according to claim 11, further characterized by having an intercepting engaging member that intercepts between the parallel link mechanism and its mounting portion in response to the rotation of the other link of the parallel link mechanism, thereby preventing the parallel link mechanism from returning to its original position.

13. The transport device according to claim 12, further comprising a release means for retracting the intercepting engagement member from the intercepting position between the parallel link mechanism and the mounting portion, thereby returning the parallel link mechanism to a rotatable state.

14. The transport device according to any one of claims 10 to 13, characterized in that the auxiliary wheels are wheels that can rotate in a direction different from the rotation direction of at least the straight-driving wheels.

15. The transport device according to claim 10 or 11, further characterized by having a temporary fixing means that automatically locks the parallel link mechanism so that it cannot rotate when the parallel link mechanism rotates to move the auxiliary wheels by a predetermined amount.

16. The transport device according to claim 15, further comprising a release means for restoring a parallel link mechanism that has become immobile due to a temporary fixing means to a rotatable state.

17. The transport device according to claim 15, characterized in that the auxiliary wheels are wheels that can rotate in a direction different from the rotation direction of at least the straight-driving wheels.

18. The transport device according to claim 16, characterized in that the auxiliary wheels are wheels that can rotate in a direction different from the rotation direction of at least the straight-driving wheels.

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