Braking mechanism

Abstract

To provide a brake mechanism which has a simple and compact structure, has high durability and a good brake function, and may change a brake force arbitrarily.SOLUTION: A brake mechanism B includes: a base part K attached to a leg part 3 pivotally supporting a wheel 1; a brake plate 8 attached to the wheel 1; at least one brake piece 4 which is disposed contacting with the brake plate 8 and generates frictional force between itself and the brake plate 8; a displacement member 7 which is provided at the base part K and causes a position of the brake piece 4 relative to the brake plate 8 to move close to or away from an axle 5 within a plane perpendicular to the axle 5; and an operation member 6 which operates the displacement member 7.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a braking mechanism that applies a constant braking force to the wheels of various vehicles such as walking carts and luggage transport carts, and that can also change the braking force, in order to prevent the body of the vehicle from moving forward alone while in motion, without requiring the user to continuously operate the brakes. [Background technology]

[0002] Conventionally, such a braking mechanism is disclosed, for example, in Patent Document 1 (

[0021] ~

[0022] and Figures 1 and 4).

[0003] In this braking mechanism, a drive gear 410, which is a ring-shaped internal gear, is provided on the wheel 400 of the handcart 100, and a driven gear 500 meshes with this drive gear 410. A reluctance motor 600 and a resistance element 700 are connected to the driven gear 500. As the wheel 400 rotates, the reluctance motor 600 rotates via the driven gear 500. This generates an eddy current between the permanent magnet 610 and the stator (metal member 620) that make up the reluctance motor 600.

[0004] On the other hand, a resistance element 700 is connected to the reluctance motor 600, which acts as a resistance to the generated eddy current, generating torque resistance in the drive gear 410. As a result, a certain deceleration buffering effect is generated in the braking mechanism.

[0005] According to the description in Patent Document 1, a braking mechanism that utilizes such resistance eliminates the need for a separate electrically driven component. Furthermore, the drive gear 410 replaces the wheel rim, making it highly versatile. Furthermore, because the driven gear 500 is provided on one side of the wheel axle 210, it can be housed directly within the wheel rim, preventing a significant increase in the volume of the wheel 400 of the handcart 100. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 6568987 Summary of the Invention [Problem to be solved by the invention]

[0007] The conventional braking mechanisms described above require a ring-shaped internal gear integral with the wheel and a driven gear that meshes with the internal gear, making the braking mechanism complex. Furthermore, the mechanism must be durable enough to maintain proper gear-to-gear rotation under various wheel driving conditions. Reluctance motors also require a relatively high rotational speed to generate the required eddy currents to obtain effective braking force, so high durability is required.

[0008] When the vehicle is running, the driven gear and motor are constantly rotating, and a constant amount of rotational resistance acts on the wheels. This rotational resistance occurs according to the rotation of the gears, and the magnitude of the rotational resistance cannot be adjusted arbitrarily depending on the running conditions, etc. As a result, smooth running is impaired when running on flat roads where braking is not required. In addition, a constant amount of noise is generated from the driven gear, which also reduces the comfort of the ride.

[0009] Furthermore, the size of the mechanism becomes larger because a driven gear is added to the wheel and a case is required to protect the motor. In particular, when using a motor that can exert a large braking force, The size of the body is becoming larger. As a result, the braking mechanism is more likely to interfere with the user's legs. Furthermore, these components are costly, making it difficult to provide an inexpensive braking mechanism.

[0010] As described above, conventional braking mechanisms have various problems that need to be solved, and there is a need to provide a braking mechanism that has a simple and compact configuration, yet has high durability and good braking function, and that allows the braking force to be changed as desired. [Means for solving the problem]

[0011] (Features and configuration) The characteristic configuration of the braking mechanism according to the present invention is as follows: a base portion attached to a leg portion that supports the wheels; attached to the wheel , having a surface perpendicular to the axle of the wheel A brake plate; abutting against the brake plate At least one braking piece that generates a friction force between itself and the braking plate; a brake piece provided on the base portion, the position of the brake piece relative to the brake plate being The axle a displacement member that moves the axle closer to or farther from the axle in a plane perpendicular to the axle; and an operating member for actuating the displacement member.

[0012] (effect) The braking pieces slide against the brake plates attached to the wheels, generating frictional force, which allows a certain braking force to be applied to the wheels.

[0013] Furthermore, when the displacement member is operated to bring the brake piece closer to the axle, the braking moment around the axle becomes smaller, allowing a weak braking force to be applied to the wheel. Conversely, when the brake piece is moved away from the axle, the braking moment around the wheel becomes larger, allowing a strong braking force to be applied to the wheel.

[0014] Since the adjustment of the magnitude of the braking force is determined by the position of the braking piece relative to the brake plate, the user of the braking mechanism can adjust the braking force simply by operating the operating member to change the position of the braking piece, eliminating the need, for example, to continuously operate the operating member with a constant force.

[0015] For example, by equipping a walker with such a braking mechanism, a constant braking force can be exerted without the user having to continually operate a brake lever, etc. As a result, when going down a slope, the user can simply keep their hands on the handlebars to maintain a constant vehicle speed, allowing the walker to be driven comfortably.

[0016] Furthermore, as in the present configuration, providing a braking piece that contacts the braking plate and providing a displacement member that changes the position of the braking piece is relatively simple and can be formed compactly. Therefore, a braking mechanism that is easy to mount on the wheels of a walking stroller or the like and has durability can be obtained. do.

[0017] (Features and configuration) In the braking mechanism according to the present invention, it is advantageous if the base portion is provided with a guide portion that guides the braking pieces movably along the direction in which the braking pieces move toward and away from each other.

[0018] (effect) In this configuration, the guide portion is responsible for the movement of the brake piece toward and away from the axle, so that the displacement member acting on the brake piece only needs to act on the brake piece in the radial direction, for example, outward or inward, relative to the axle, which makes it easier to simplify the configuration of the displacement member.

[0019] Furthermore, when the brake pieces are displaced, the guide parts restrict the rotation of the brake pieces, which tend to rotate integrally with the brake plates. However, because the guide parts are provided on the base part, the structure is strong and can reliably restrict the rotation of the brake pieces. Therefore, the displacement member only needs to act on the brake pieces when moving the brake pieces toward or away from the axle, which reduces the strength of the displacement member. This also allows the displacement member to be made more compact.

[0020] (Features and configuration) In the braking mechanism of the present invention, a rotation restriction portion can be provided between the braking piece and the displacement member, or between the braking piece and the guide portion, to prevent the braking piece from rotating due to sliding against the braking plate.

[0021] (effect) When the brake piece slides against the brake plate, a difference in relative speed occurs between the area of ​​the brake piece closest to the axle and the area farther from the axle. This can cause the brake piece to rotate on its axis. When the brake piece rotates, a rolling force is generated against the guide part and the displacement member, displacing the brake piece and causing fluctuations in the braking force. To prevent this and stabilize the braking force, the braking mechanism becomes more complex, for example by providing a separate structure to hold the displacement member in position.

[0022] Therefore, as in this configuration, a configuration is provided that stops the rotation of the braking piece across the braking piece and the displacement member or across the braking piece and the guide portion.

[0023] The structure for stopping the relative rotation between the braking piece and the abutting member is generally simple, and a stable braking force can be exerted without complicating the structure of the braking mechanism. In addition, wear on the guide part and the displacement member is reduced, thereby increasing the durability of the braking mechanism.

[0024] (Features and configuration) In the braking mechanism of the present invention, a cylindrical surface against which the side of the braking piece can abut when the braking piece is positioned at the innermost or outermost position can be provided on at least one of the brake plate and the boss portion and rim portion of the wheel.

[0025] (effect) In this configuration, when the braking pieces are positioned at the innermost or outermost positions, they come into contact with the cylindrical surfaces of the braking plates and / or the boss and rim, thereby increasing the braking force.

[0026] For example, if a cylindrical surface is provided on the innermost part of the brake plate or on the boss of the wheel, the braking force generated by friction between the brake plate and the brake piece is minimized just before the brake piece contacts the cylindrical surface because the distance from the axle to the brake piece is short. Furthermore, if the wheel is made of a resin or other material, making the boss on the inner circumference a non-magnetic area, no braking force is generated. By contacting the brake piece with the inner cylindrical surface from this state, the braking force can be increased. Therefore, by changing the pressing force of the brake piece against the inner cylindrical surface, this braking mechanism can be used, for example, as a running brake.

[0027] On the other hand, if a cylindrical surface is provided on the outermost part of the brake plate or on the wheel rim, the braking force generated by friction between the brake plate and brake plate is at its maximum just before the brake piece contacts the cylindrical surface, because the distance from the axle to the brake piece is the longest. By bringing the brake piece into contact with the outer cylindrical surface from this state, the braking force can be further increased. In this case, the wheel can be completely stopped by varying and increasing the pressing force of the brake piece against the cylindrical surface, and this braking mechanism can be used, for example, as a parking brake.

[0028] (Features and configuration) In the braking mechanism according to the present invention, the braking plates may be made of magnetic material, and the braking pieces may be made of magnets.

[0029] (effect) In this configuration, the braking piece, which is a magnet, is always attracted and held to the braking plate. In other words, unlike common braking mechanisms in which the braking piece is supported on a separate member from the braking plate and acts on the braking plate, the attraction force generated between the braking plate and braking piece is approximately constant.

[0030] Therefore, by moving the position of the braking piece in the radial direction using the operating member and the displacement member, the braking moment around the axle can be easily adjusted to a desired magnitude.

[0031] Furthermore, by appropriately setting the strength of the magnetic force of the magnets used and the number of magnets, the braking force to be generated can be freely set, thereby providing a braking mechanism with a high degree of freedom in setting the braking function.

[0032] (Features and configuration) In the braking mechanism of the present invention, it is advantageous that the brake plate is provided in a circular shape on the outer circumferential side of the side of the wheel, the area of ​​the side exposed on the inside of the circular brake plate is a non-magnetic area, and the displacement member is configured to be able to change the position of the braking piece between the position where it abuts the brake plate and the non-magnetic area.

[0033] (effect) With this configuration, by moving the braking pieces to the non-magnetic area on the inner periphery, it is easy to create a state where no braking force is applied to the wheel. Furthermore, by gradually moving the braking pieces from this state toward the outer periphery, the contact area with the brake plate can be increased, gradually increasing the braking force. By utilizing this braking effect, for example, when this braking mechanism is used on the wheels of a walker, a brake that functions as both a running brake and a parking brake can be obtained. [Brief explanation of the drawings]

[0034] [Figure 1] FIG. 1 is an explanatory diagram showing the appearance of a vehicle equipped with a braking mechanism according to a first embodiment of the present invention; [Figure 2] FIG. 1 is an exploded perspective view showing a braking mechanism according to a first embodiment; [Figure 3] 1 is a cross-sectional view showing a braking mechanism according to a first embodiment; [Figure 4] FIG. 1 is an explanatory diagram showing an operation mode of the braking mechanism according to the first embodiment; [Figure 5] FIG. 10 is an exploded perspective view showing a braking mechanism according to a second embodiment of the present invention. [Figure 6] FIG. 10 is an exploded perspective view showing a braking mechanism according to a third embodiment of the present invention. [Figure 7] FIG. 10 is an explanatory diagram showing the appearance of a vehicle equipped with a braking mechanism according to a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0035] (overview) This braking mechanism B is preferably attached to the wheels 1 of a vehicle S that is run without a user, such as a walking cart or a dolly for transporting luggage. This braking mechanism B can generate a predetermined braking force without the user having to operate the brake lever 2 or the like, or without continuously operating the brake lever 2, when the vehicle S is running down a long slope, for example.

[0036] [First embodiment] 1 to 4 show a first embodiment of a braking mechanism B according to the present invention. As shown in Fig. 1 and Fig. 2, the braking mechanism B of this embodiment has a base section K attached to a leg section 3 of a vehicle S, and at least one braking piece 4 for braking a wheel 1 is provided on this base section K. This braking piece 4 is provided at a position on the base section K facing the wheel 1, and moves toward and away from the axle 5 in a plane perpendicular to the axle 5 of the wheel 1. However, in principle, it always moves relative to the running wheel 1.

[0037] When the braking mechanism B is provided on a walking vehicle, for example, the user operates the brake lever 2 via an operating member 6 such as a cable 6a, which changes the attitude of the displacement member 7 and alters the position of the braking piece 4. When the vehicle S is traveling downhill, the user adjusts the position of the operating member 6, causing the braking piece 4 to move to a position a predetermined distance away from the axle 5 of the wheel 1, generating frictional force with the brake plate 8 and braking the wheel 1. This braking force increases or decreases depending on the distance between the axle 5 and the braking piece 4, so that the desired braking function can be exerted depending on the traveling state of the vehicle S.

[0038] (base part) 2, the base portion K and the leg portion 3 of the vehicle S are integrated, for example, by inserting the leg portion 3 into a fixing hole formed in the base portion K. The base portion K includes a first base portion K1 attached to the leg portion 3 and a disk-shaped second base portion K2 that guides the movement of the braking piece 4. In this embodiment, the first base portion K1 and the second base portion K2 are integrally formed using various resin materials. However, they may be formed separately and connected to each other.

[0039] The second base portion K2 is provided with a guide portion 9 that guides at least one braking piece 4 so that it can move toward and away from the axle 5 of the wheel 1. The guide portion 9 has a linear groove 9a formed therein, for example, as shown in FIG. 2. In this embodiment, the linear groove 9a extends laterally with respect to the wheel hole 10 through which the axle 5 is inserted, and along the radial direction of the wheel 1. The width of the linear groove 9a is configured to be slightly larger than the diameter of the disc-shaped braking piece 4.

[0040] Meanwhile, a bottom surface 9b is formed at the bottom of the linear groove 9a, facing the back surface of the braking piece 4, to prevent the braking piece 4 from moving excessively away from the braking plate 8. Furthermore, a guide groove 9c is provided in the center of the bottom surface 9b along the extension direction of the linear groove 9a. An operating shaft 4a of the braking piece 4, which will be described later, is disposed in this guide groove 9c, allowing the braking piece 4 to be operated by the displacement member 7.

[0041] Such linear grooves 9a can be formed by, for example, injection molding of resin, or by machining the material that constitutes the base portion K with a milling machine, which reduces the number of machining steps and reduces the machining cost.

[0042] With this guide portion 9, when the wheel 1 rotates, the wall portion 9d of the guide portion 9 abuts against the braking piece 4 that is attracted to the brake plate 8 and tries to rotate together with the wheel 1, preventing the braking piece 4 from rotating together. Because this wall portion 9d is configured as part of the base portion K, it can generate a reaction force sufficient to receive the braking piece 4. Therefore, it is possible to arbitrarily set the strength of the attraction force of the braking piece 4 to the brake plate 8.

[0043] (Brake piece) 2 and 3, one braking piece 4 is placed in the linear groove 9a. The braking piece 4 is, for example, a magnet 4b, and is formed in a cylindrical shape with a height that is short compared to its outer diameter, with the outer periphery of the magnet 4b covered by a cup-shaped case 4c. The case 4c is made of a magnetic material such as steel, and concentrates the magnetic flux generated by the magnet 4b to increase its magnetic force and also functions to protect the magnet 4b.

[0044] Furthermore, it is advisable to attach a durable sliding member 4d, such as a thin carbon plate, to the portion of the braking piece 4 that comes into contact with the braking plate 8. This sliding member 4d makes it possible to adjust the frictional force generated between the braking piece 4 and the braking plate 8. For example, the thicker the sliding member 4d, the less magnetizing force of the magnet 4b against the braking plate 8, thereby weakening the braking force.

[0045] A rod-shaped operating shaft 4a protrudes from the rear surface of the cup-shaped case 4c. The operating shaft 4a is disposed so as to pass through the guide groove 9c and is engaged with one end of the displacement member 7. By operating the displacement member 7, the braking piece 4 can be set to any position along the linear groove 9a.

[0046] The braking piece 4 shown in this embodiment is cylindrical and has no directionality around the operating shaft 4a, making it easy to install in the linear groove 9a. Furthermore, the braking piece 4 can rotate when it moves inside the linear groove 9a or when it slides against the braking plate 8 at a specific point in the linear groove 9a. Therefore, the sliding direction of the braking piece 4 against the braking plate 8 changes appropriately, and the degree of wear on the thin carbon plate and the case 4c is evened out.

[0047] Furthermore, since the guide portion 9 is provided on the base portion K, the structure is strong and can reliably restrict the rotation of the braking piece 4. Therefore, the displacement member 7 only needs to act on the braking piece 4 when moving the braking piece 4 toward or away from the axle 5, and the component strength of the displacement member 7 can be reduced. This also makes it possible to make the displacement member 7 more compact.

[0048] (Brake plate) As shown in Figures 2 and 3, a brake plate 8 is attached to the side of the wheel 1. The brake plate 8 is a plate member with an annular area that comes into contact with the braking piece 4. The wheel 1 is molded from resin, for example, but the brake plate 8 is made of, for example, a magnetic steel material so that the braking piece 4 can be attracted to it. The brake plate 8 is attached to the wheel 1 using, for example, screws 11 as shown in Figure 2. Alternatively, it can be fixed using adhesive or the like.

[0049] As shown in Figure 2, the radial width of the brake plate 8 is at least larger than the diameter of the brake piece 4. If the width of the brake plate 8 is sufficiently larger than the diameter of the brake piece 4, it is possible to set a wide range of braking force by changing the position of the brake piece 4. For example, the further radially outward the brake piece 4 is located, the larger the arm dimension from the axle 5 becomes, and the greater the braking force calculated by multiplying it by the friction force.

[0050] Furthermore, even if the radial width of the brake plate 8 is the same as the diameter of the brake piece 4, it is possible to adjust the braking force. In this case, part or all of the brake piece 4 can be positioned away from the brake plate 8 toward the axle 5. As shown in Figure 2, a non-magnetic region NM is formed on the inner periphery of the brake plate 8 by using the boss portion 1a of the wheel 1 so that it is flush with the plate surface of the brake plate 8, allowing the brake piece 4 to move across both regions.

[0051] In this case, for example, if half the area of ​​the braking piece 4 is brought into contact with the braking plate 8, the braking force will be approximately halved. Furthermore, if the braking piece 4 is completely disengaged from the braking plate 8 toward the axle 5, the braking force will be zero. By making the generated braking force variable in this way, for example, if this braking mechanism B is used on the wheel 1 of a walker, it can be used as a running brake.

[0052] Furthermore, as shown in FIG. 2, the outer edge of the brake plate 8 is provided with a cylindrical surface 8a against which the side of the braking piece 4 can abut. In other words, when the braking piece 4 is in its outermost position, the abutment between the side of the braking piece 4 and the cylindrical surface 8a further increases the total amount of frictional force generated by the braking piece 4. The braking piece 4 attempts to rotate on its axis due to contact with the cylindrical surface 8a, but this rotation does not necessarily have to be stopped. If a structure were provided to stop the rotation of the braking piece 4, frictional force would certainly be generated between the side of the braking piece 4 and the cylindrical surface 8a. However, even if the braking piece 4 is able to rotate on its axis, a certain increase in frictional force between the braking piece 4 and the cylindrical surface 8a can be expected, except when the braking piece 4 and the cylindrical surface 8a rotate relative to each other without slippage.

[0053] This configuration makes it possible, for example, to completely stop the rotation of the wheel 1. When the braking force generated by the brake piece 4 and the brake plate 8 is greater than the static friction force between the wheel 1 and the road surface, the wheel 1 locks, resulting in a state equivalent to when the parking brake is applied. In this way, with this configuration, it is possible to obtain a braking mechanism B that has both a running brake and a parking brake.

[0054] By configuring the brake plate 8 from a magnetic material and configuring the brake piece 4 using a magnet 4b, the brake piece 4 is always attracted to the brake plate 8. This configuration differs from the general braking mechanism B in that the brake piece 4 is supported by a member separate from the brake plate 8 and acts on the brake plate 8, and the attraction force generated between the brake plate 8 and the brake piece 4 is approximately constant.

[0055] Therefore, by moving the position of the braking piece 4 in the radial direction of the axle 5 using the operating member 6 and the displacement member 7, the magnitude of the braking moment acting on the axle 5 can be easily adjusted.

[0056] Furthermore, the braking force can be freely set by appropriately setting the strength and size of the magnetic force of the magnet 4b, so that a braking mechanism B can be obtained that has a simple configuration yet has a high degree of freedom in setting the braking function.

[0057] (displacement member) The position of the braking piece 4 is adjusted by a displacement member 7. As shown in Figures 2 to 4, the displacement member 7 is a substantially L-shaped member pivotally supported on the back surface of the base part K. A pivot hole 7a provided in the central bent part is pivotally supported on the base part K, and a fork part 7b provided at one end engages with the operating shaft part 4a of the braking piece 4. An operating member 6, i.e., a cable 6a extending from the brake lever 2 of a walker, for example, is connected to an operating hole 7c provided at the other end.

[0058] In this embodiment, the operating shaft 4a engages with the fork portion 7b, and while the fork portion 7b rotates around the pivot hole 7a, the operating shaft 4a moves back and forth linearly along the guide groove 9c. In this embodiment, a spring 12 is connected to the displacement member 7, and biases the brake piece 4 so as to pull it toward the axle 5. This counteracts the radial outward movement of the brake piece 4, which is the magnet 4b, attracted to the brake plate 8 when the brake piece 4 is brought closer to the axle 5. By providing this spring 12, not only can the brake piece 4 be prevented from shifting in position, but the operating force of the displacement member 7 can also be reduced.

[0059] When the walker is running normally, the force pulling the cable 6a via, for example, the brake lever 2 is zero. In this state, the displacement member 7 is in the position shown by the solid line in Figure 4, with the fork portion 7b closest to the axle 5. In this state, the braking piece 4 does not come into contact with the braking plate 8.

[0060] When the user of the walker operates the brake lever 2 and pulls the cable 6a, the fork portion 7b moves radially outward as shown by the dashed line in Figure 4, and the brake piece 4 begins to slide against the brake plate 8. The braking force increases as the contact area between the brake piece 4 and the brake plate 8 increases. After the entire surface of the brake piece 4 comes into contact with the brake plate 8, further movement of the brake piece 4 radially outward extends the moment arm from the axle 5 to the brake piece 4, increasing the braking force.

[0061] 2 and 4, the displacement member 7 may be structured so that its position can be changed according to the operating force of the user, or so that it can be fixed in a predetermined position. For example, although not shown, by connecting an operating dial with a click mechanism or the like to the end of the cable 6a connected to the displacement member 7 and installing this near the handle H, the position of the braking piece 4 can be fixed according to the selected position of the operating dial.

[0062] In this case, a predetermined braking force is generated according to each setting position without the user having to perform any special operation after that. Therefore, when traveling downhill, the user can simply keep their hands on the handlebars H to maintain a constant vehicle speed, allowing the walker to be driven comfortably.

[0063] Furthermore, as in this configuration, it is relatively easy to provide the braking piece 4 that contacts the braking plate 8 and the displacement member 7 that changes the position of the braking piece 4, making it possible to form a compact braking mechanism B. Therefore, it is possible to obtain a durable braking mechanism B that is easy to mount on the wheel 1 of a walking stroller or the like.

[0064] Second Embodiment In the braking mechanism B according to the present invention, the displacement member 7 or the guide portion 9 may be provided with a rotation restricting portion R that prevents the braking piece 4 from rotating when sliding against the braking plate 8.

[0065] When the braking piece 4 slides against the braking plate 8, a difference occurs in the relative speed between the area of ​​the braking piece 4 that is close to the axle 5 and the area that is far from the axle 5. This makes the braking piece 4 more likely to rotate. When the braking piece 4 rotates, a rolling force is generated against the guide part 9 and the displacement member 7, causing the braking piece 4 to move and changing the braking force. In order to stabilize the braking force, it is necessary to stop the rotation of the braking piece 4 and reliably hold the position of the displacement member 7.

[0066] Specifically, as shown in FIG. 5, a rotation restricting portion R is provided on the back side of the braking piece 4. This rotation restricting portion R is shaped like a rectangular pillar and has a female thread. A bolt 4f is fixed to the back side of one of the braking pieces 4, and the rotation restricting portion R is screwed onto this bolt 4f. Two parallel surfaces of the rotation restricting portion R form a first restricting surface R1. In addition, an operating shaft 4a with which the displacement member 7 engages is screwed onto the rotation restricting portion R.

[0067] Although not shown in the drawings, the ends of the bolt 4f and the operating shaft 4a abut against each other inside the rotation restricting portion R. Therefore, for example, by strongly screwing the operating shaft 4a into the rotation restricting portion R, the bolt 4f and the operating shaft 4a are locked and fixed to the female thread portion of the operating shaft 4a.

[0068] On the other hand, the width of the guide groove 9c of the second base portion K2 is set to match the first restriction surface R1 which is parallel to each other, so that the rotation restriction portion R does not rotate inside the guide groove 9c. The surface facing this guide groove 9c is defined as the second restriction surface R2.

[0069] By providing such a rotation restricting portion R, it is possible to reliably restrict the rotation of the braking piece 4 while limiting it to the addition of a simple configuration, and it is possible to stabilize the braking force.

[0070] Furthermore, since the braking pieces 4 do not rotate relative to the guide portion 9 and the displacement member 7, wear on the guide portion 9 and the displacement member 7 is reduced, and the durability of the braking mechanism B can be increased.

[0071] 5, as a configuration for restricting the rotation of the braking piece 4, for example, instead of forming the tip of the displacement member 7 into a fork shape, a square hole may be formed at the tip, and the operating shaft portion 4a of the braking piece 4 may be formed into a square pillar so that the braking piece 4 cannot rotate relative to the displacement member 7. In this case, the movement locus of the braking piece 4 will be the movement locus of the square hole in the displacement member 7. With this configuration, the strength of the displacement member 7 is required to reliably maintain the position of the braking piece 4, but it is also possible to omit the linear groove 9a and guide groove 9c in the base portion K, making it possible to configure the braking mechanism B more simply.

[0072] Third Embodiment In the braking mechanism B of the present invention, as shown in Figure 6, an inner cylindrical surface 8b can be provided on the side of the boss portion 1a of the wheel 1, and the side of the braking piece 4 can be configured to abut against it when the braking piece 4 is positioned at the innermost position.

[0073] When the inner cylindrical surface 8b is provided, the distance from the axle 5 to the brake piece 4 is shortest just before the brake piece 4 comes into contact with the inner cylindrical surface 8b. This minimizes the braking force generated by friction between the brake piece 4 and the brake plate 8. Furthermore, when the non-magnetic region NM is provided on the inner periphery, no braking force is generated. By bringing the brake piece 4 into contact with the inner cylindrical surface 8b from this state, the braking force can be increased without significantly changing the position of the brake piece 4. In this case, the braking force can be changed by operating the brake lever 2, etc., to change the pressing force of the brake piece 4 against the inner cylindrical surface 8b, allowing it to be used as a running brake.

[0074] In this case, it is also advisable to provide various sliding plates on the side surfaces of the braking pieces 4 to increase the frictional force with the inner cylindrical surface 8b. It is also advisable to provide a rotation restricting portion R between the braking pieces 4 and the second base portion K2 or between the braking pieces 4 and the displacement member 7.

[0075] [Fourth embodiment] As shown in Fig. 7, the braking force may be adjusted by an adjustment switch 21 provided near the handle H. The adjustment switch 21 is provided with, for example, a toggle-type lever 21a, and the attitude of the displacement member 7 is adjusted by selecting the position of the lever 21a. The lever 21a may have any configuration, such as one that allows its position to be set continuously or in stages.

[0076] Other Embodiments The contact of the braking pieces 4 with the braking plates 8 may be achieved by using a biasing member such as a spring of various shapes, in addition to using a magnetic force. [Industrial Applicability]

[0077] The braking mechanism of the present invention is suitable for use in vehicles such as walkers and luggage transport carts, especially those that are operated without a user riding on them. It can also be installed in other vehicles such as bicycles and automobiles that are ridden by a user. Furthermore, it can be used in any device that requires constant braking of the rotation of a rotating body, not just vehicles. [Explanation of symbols]

[0078] 1 wheel 1a Boss part 1b Rim section 3 legs 4 Brake piece 4b Magnet 5 axles 6 Operating member 7 Displacement member 8 Brake plate 8a Cylindrical surface 9 Guide section B Braking mechanism K base part NM non-magnetic region R Rotation control section

Claims

1. a base portion attached to a leg portion that supports the wheels; a brake plate attached to the wheel and having a surface perpendicular to the axle of the wheel; At least one braking piece that comes into contact with the braking plate to generate a friction force between the braking piece and the braking plate; a displacement member provided on the base portion, which moves the position of the braking piece relative to the brake plate toward or away from the axle in a plane perpendicular to the axle; an operating member that actuates the displacement member.

2. 2. The braking mechanism according to claim 1, wherein the base portion is provided with a guide portion that guides the braking pieces movably in the direction in which the braking pieces move toward and away from each other.

3. 3. The braking mechanism according to claim 2, wherein a rotation restricting portion is provided between the braking piece and the displacement member, or between the braking piece and the guide portion, to prevent the braking piece from rotating due to sliding against the braking plate.

4. 4. A braking mechanism according to claim 1, wherein a cylindrical surface against which the side of the braking piece can abut when the braking piece is positioned at the innermost or outermost position is provided on at least one of the brake plate and the boss portion and rim portion of the wheel.

5. 5. The braking mechanism according to claim 1, wherein the braking plate is a magnetic member, and the braking piece is a magnet.

6. 6. A braking mechanism as described in claim 5, wherein the brake plate is provided in an annular shape on the outer circumferential side of the side of the wheel, the area of ​​the side exposed on the inside of the annular brake plate is a non-magnetic area, and the displacement member is configured to be able to change the position of the braking piece between the position where it abuts against the brake plate and the non-magnetic area.

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