Carrying cart
The carrier cart addresses the challenge of traversing convex steps by using a combination of driving and idler wheels with elastic attachments, allowing for efficient and smooth travel with reduced driving force and enabling smaller, lighter, and less conspicuous wheels.
Patent Information
- Application Number
- JP2023208586
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2023-12-11
- Publication Date
- 2025-06-23
AI Technical Summary
Carrier carts struggle to overcome convex steps while traveling, as the driven wheel in front of the drive wheel often gets hindered, requiring a mechanism to facilitate smooth traversal with minimal driving force.
The carrier cart incorporates driving wheels, front idler wheels, and rear idler wheels, with the driving wheels attached to the cart body via an intervening member and the idler wheels attached via elastic bodies, allowing for efficient traversal of steps by distributing the load and using elastic deformation to lift wheels and reduce the required driving force.
This configuration enables the carrier cart to overcome steps with a smaller driving force, ensuring smooth travel even over convex obstacles, while also allowing for reduced wheel diameters, lighter construction, and improved aesthetics.
Smart Images
Figure 2025093081000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a carrier cart that includes wheels that roll on a road surface by rotating about an axle, and a cart body portion on which an object to be conveyed such as luggage is placed, and travels by the rolling of the wheels.
Background Art
[0002] A carrier cart includes wheels that roll on a road surface by rotating about an axle, and a cart body portion on which an object to be conveyed such as luggage is placed. As one form of the carrier cart, there is a cart in which the wheels include a drive wheel that is rotationally driven by a power source such as a motor, and a driven wheel disposed at least in front of the drive wheel in the front-rear direction (see, for example, Patent Document 1). In this carrier cart, when the drive wheel is rotationally driven by a power source, a propulsive force for causing the carrier cart to travel is generated in the drive wheel. A part of this propulsive force is transmitted to the driven wheel via the cart body portion. The driven wheel rotates in conjunction with the drive wheel, thereby rolling on the road surface. A carrier cart with an object to be conveyed placed on the cart body portion travels (self-propels) by the rolling of the drive wheel and the driven wheel.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] By the way, when the driven wheel in front of the drive wheel comes into contact with a convex step while the carrier cart is traveling forward, the step hinders the travel. The carrier cart is required to continue traveling forward even after contact with the step. There is a demand for a carrier cart that can overcome a step with all the wheels, particularly the driven wheel in front of the drive wheel, by rotating the drive wheel with a small driving force.
Means for Solving the Problem
[0005] The carrier cart for solving the above problems includes: wheels that roll on the road surface by rotating around an axle; and a cart body portion that is disposed above the grounding portion of the wheels on the road surface and on which an object to be conveyed is placed. The wheels include: driving wheels that are rotationally driven by a power source; front idler wheels that are disposed in front of the driving wheels; and rear idler wheels that are disposed behind the driving wheels. The carrier cart travels by the rolling of the wheels. The driving wheels are attached to the cart body portion via an intervening member, and the front idler wheels and the rear idler wheels are each attached to the cart body portion via an elastic body.
Brief Description of the Drawings
[0006]
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DETAILED DESCRIPTION OF THE INVENTION
[0007] (First Embodiment) Hereinafter, the first embodiment of the carrier cart will be described with reference to FIGS. 1 to 12. As shown in FIG. 1, the carrier cart CC includes a plurality of wheels that roll on the road surface 10 by rotating about an axle, and a cart main body 20 on which an object to be transported (not shown), such as luggage, is placed. In the first embodiment, five wheels are used. The wheels include a single drive wheel 30, a pair of front driven wheels 40, and a pair of rear driven wheels 50. The carrier cart CC is assumed to travel from right to left in FIG. 1 by the rolling of each wheel. This also applies to FIGS. 4 to 12, and also to FIG. 13 for explaining the second embodiment, and further to FIG. 14 for explaining the third embodiment. In FIGS. 1 and 4 to 14, only one of the pair of front driven wheels 40 is shown, and only one of the pair of rear driven wheels 50 is shown.
[0008] In the following description, the forward direction of the carrier cart CC is defined as the front, and the reverse direction is defined as the rear for explanation. Also, the vertical direction means the vertical direction of the carrier cart CC, and the horizontal direction is a direction orthogonal to both the forward direction and the vertical direction. The horizontal direction is the width direction of the carrier cart CC and is assumed to coincide with the horizontal direction when the carrier cart CC is moving forward.
[0009] <road surface 10> The road surface 10 on which the carrier cart CC travels has a convex step 12. Here, in order to distinguish the convex step 12 from a portion different from the step 12 on the road surface 10, the latter is referred to as the general road surface 11. Also, the upper surface of the step 12 is referred to as the top surface 13, and the rear upper corner of the step 12 is referred to as the rear corner 14. For the sake of simplicity of explanation, here it is assumed that both the general road surface 11 and the top surface 13 are composed of horizontal planes.
[0010] The top surface 13 is formed by, for example, the upper surface of a sidewalk. The general road surface 11 is formed by, for example, the upper surface of a roadway. The vertical dimension (height) of the step 12, that is, the height difference between the general road surface 11 and the top surface 13, is 30 mm or less, and about 20 mm is assumed in the first embodiment.
[0011] <Cart main body 20> The cart main body 20 is disposed above the grounding locations of both front driven wheels 40, drive wheel 30, and both rear driven wheels 50 with respect to the road surface 10. In the first embodiment, the cart main body 20 is disposed at a position higher than both front driven wheels 40, drive wheel 30, and both rear driven wheels 50. Note that in each figure, the cart main body 20 is illustrated in a simplified manner.
[0012] <Drive wheel 30> The drive wheel 30 is disposed at the central portion in the front - rear direction and at the central portion in the left - right direction within the lower space of the cart main body 20. The drive wheel 30 is rotationally driven about an axle 31 extending in the vehicle width direction by a motor (not shown) as a power source. The motor is supplied with power from a battery (not shown) mounted on the cart main body 20 or the like and operates.
[0013] The drive wheel 30 is rotationally driven to apply a propulsive force for traveling to the cart main body 20. As the above - mentioned motor, for example, an in - wheel motor, which is a type of electric motor disposed inside or near the wheel of the drive wheel 30, transmits power to the drive wheel 30, and directly rotationally drives the drive wheel 30, may be used. As shown in FIGS. 1 and 2, both ends of the axle 31 project outward in both sides in the left - right direction from the drive wheel 30.
[0014] <Mounting structure of drive wheel 30> The drive wheel 30 is attached to the cart main body 20 via an intervening member formed of a rigid body. In the first embodiment, an attachment member 32, a support member 33, a bolt 34, a nut 35, and a fastening member 37 are used as the intervening member.
[0015] The attachment member 32 is disposed directly below the cart main body 20. The attachment member 32 is attached to the cart main body 20 from below by fastening using a fastening member 37 such as a bolt at a plurality of locations. The attachment member 32 has an attachment plate portion 32a at a position lower than the fastening location by the fastening member 37.
[0016] The support member 33 is disposed below the mounting plate portion 32a. The support member 33 includes a pair of support arm portions 33a that are spaced apart in the left - right direction and each have a bearing hole 36, and a connecting plate portion 33b that connects the upper end portions of both support arm portions 33a. The connecting plate portion 33b is fastened to the mounting plate portion 32a by bolts 34 and nuts 35.
[0017] The drive wheel 30 is disposed between both support arm portions 33a. Among the axles 31, the portions that protrude outward on both sides in the left - right direction from the drive wheel 30 are rotatably supported with respect to the bearing holes 36 of the adjacent support arm portions 33a.
[0018] <Front idler wheel 40> As shown in FIG. 1, the pair of front idler wheels 40 are disposed at a location in the lower space of the cart main body portion 20 that satisfies the following conditions.
[0019] · In the front - rear direction, it is a location away from the drive wheel 30 toward the front. · In the left - right direction, it is a location away from both sides in the same direction with respect to the central portion.
[0020] Here, generally, the wheels can cross the step 12 when the height of the step 12 is up to about 55% of the radius of the wheels. From this perspective, in the first embodiment, as the front idler wheels 40, those having a wheel diameter (diameter) of about 100 mm are used. Note that "crossing the step 12" means that the wheel crosses the corner portion 14 of the convex step 12. Therefore, the state where the wheel is located on the top surface 13 of the step 12, that is, the state of riding on the top surface 13 of the step 12 is also included in the crossed state.
[0021] As shown in FIGS. 1 and 3, each front idler wheel 40 is rotatable about an axle 41 extending in the left - right direction. Both end portions of each axle 41 protrude outward on both sides in the left - right direction from the front idler wheel 40.
[0022] <Mounting structure of each front idler wheel 40> Each front idler wheel 40 is attached to the cart body 20 via a support member 42 and an elastic body.
[0023] The support member 42 includes a pair of support arm portions 42a that are spaced apart in the left - right direction and each have a bearing hole 48, and a connecting plate portion 42b that connects the upper end portions of both support arm portions 42a. Each support arm portion 42a is disposed in a state inclined with respect to the vertical plane such that it is located more forward at the lower side when the cart body 20 is in a horizontal state (see FIG. 1).
[0024] The front idler wheel 40 is disposed between both support arm portions 42a. Among the axle 41, the portions protruding outward in both sides in the left - right direction from the front idler wheel 40 are rotatably supported with respect to the bearing holes 48 of the adjacent support arm portions 42a.
[0025] The elastic body is constituted by a rubber bush 43 having a first attached portion 44, a second attached portion 45, and an elastic connecting portion 46. The rubber bush 43 has a central axis line CL1 inclined with respect to the vertical plane such that it is located more forward at the lower side when the cart body 20 is in a horizontal state. Each of the above - described constituent members of the rubber bush 43 is disposed along the central axis line CL1, that is, in a state inclined with respect to the vertical plane such that it is located more forward at the lower side.
[0026] The first attached portion 44 is located at the top of the rubber bush 43. The first attached portion 44 is formed of a hard plate material such as a metal plate. The first attached portion 44 is attached to the cart body 20 from below by fastening using a fastening member 49 such as a bolt.
[0027] The second attached portion 45 is located at the bottom of the rubber bush 43. The second attached portion 45 is located at a position obliquely forward and downward and spaced apart from the first attached portion 44. The second attached portion 45 is formed of a hard material such as a metal material. The second attached portion 45 has a threaded hole and has a cylindrical shape with both ends open.
[0028] The elastic connecting portion 46 is formed of rubber so as to be elastically deformable. The elastic connecting portion 46 is formed in a bowl shape with an upper end opened in a circular shape, or in other words, in a concave cup shape (hemispherical shape, dome shape). The elastic connecting portion 46 has a curved surface curved in a hemispherical shape on its outer peripheral surface and inner peripheral surface.
[0029] Note that the elastic connecting portion 46 may have a frustum of a cone shape, a frustum of a pyramid shape, or the like. Further, the upper end of the elastic connecting portion 46 may be opened in a shape different from a circular shape. The elastic connecting portion 46 connects the first adhered portion 44 and the second adhered portion 45. More specifically, the upper end portion of the elastic connecting portion 46 is joined to the first adhered portion 44 from below. The bottom portion of the elastic connecting portion 46 is formed so as to surround a portion excluding the upper end surface and the lower end surface of the second adhered portion 45, and is joined to the portion surrounded as described above in the second adhered portion 45.
[0030] And a bolt 47 is inserted through the connecting plate portion 42b of the support member 42 from below. Among the bolt 47, the portion above the connecting plate portion 42b is screwed into the screw hole of the second adhered portion 45.
[0031] <Rear driven wheel 50> A pair of rear driven wheels 50 are arranged at a location in the lower space of the cart main body portion 20 that satisfies the following conditions.
[0032] · In the front-rear direction, it is a location away from the drive wheel 30 to the rear. · In the left-right direction, it is a location away from the central portion to the outer sides on both sides in the same direction.
[0033] Each rear driven wheel 50 is rotatable about an axle 51 extending in the left-right direction. Both end portions of each axle 51 project outward from the rear driven wheel 50 to both sides in the left-right direction. <Mounting structure of each rear driven wheel 50> Each rear driven wheel 50 is attached to the cart main body 20 from below via a support member 42 and a rubber bush 43. These support member 42 and rubber bush 43 have the same structure as those used in the attachment structure of each front driven wheel 40 described above.
[0034] However, the attachment structure of each rear driven wheel 50 is different from the attachment structure of each front driven wheel 40 described above in the following points when the cart main body 20 is in a horizontal state. · Each support arm portion 42a is arranged in a state inclined with respect to the vertical plane so that it is located more rearward toward the lower side.
[0035] · The central axis line CL1 of the rubber bush 43 is inclined with respect to the vertical plane so that it is located more rearward toward the lower side. Therefore, the first adhered portion 44, the second adhered portion 45, and the elastic connecting portion 46 constituting the rubber bush 43 are arranged in a state inclined with respect to the vertical plane so that they are located more rearward toward the lower side.
[0036] <Operation of the First Embodiment> Next, the operation of the carrier cart CC of the first embodiment configured as described above will be described with reference to FIGS. 1, 4 to 12. In this carrier cart CC, it is assumed that an object to be conveyed is placed on the cart main body 20.
[0037] As shown in FIG. 1, when the drive wheel 30, both front driven wheels 40, and both rear driven wheels 50 are in contact with a general road surface 11 composed of a horizontal plane, the cart main body 20 is in a horizontal state. At this time, the center of gravity of the carrier cart CC is located at the central portion in the front-rear direction. The object to be conveyed is supported in a state of being balanced in weight by both front driven wheels 40, the drive wheel 30, and both rear driven wheels 50.
[0038] As shown by the arrow in FIG. 1, when the drive wheel 30 is rotationally driven forward and downward (counterclockwise direction in FIG. 1) by the motor, a propulsive force for causing the carrier cart CC to travel forward is generated on the drive wheel 30. A part of this propulsive force is transmitted to the cart main body 20 via the support member 33 and the attachment member 32. A part of the propulsive force transmitted to the cart main body 20 is transmitted to each of the front idler wheels 40 and each of the rear idler wheels 50 via the rubber bush 43 and the support member 42. The two front idler wheels 40 and the two rear idler wheels 50 rotate in the same direction, that is, forward and downward (counterclockwise direction in FIG. 1) in conjunction with the drive wheel 30.
[0039] The drive wheel 30, the two front idler wheels 40, and the two rear idler wheels 50 roll forward on the general road surface 11. The carrier cart CC travels (runs) forward along the general road surface 11 while maintaining the posture of the cart main body 20, that is, while maintaining a horizontal state.
[0040] When there is a step 12 convex in the forward direction of travel of the carrier cart CC, as shown in FIG. 4, the two front idler wheels 40 come into contact with the rear side corner portion 14 of the step 12 from behind. Along with this contact, a force acting obliquely forward and downward acts on the corner portion 14 from the two front idler wheels 40. In particular, since the object to be conveyed is placed on the cart main body 20, when the forward travel of the carrier cart CC is restricted by the contact between the two front idler wheels 40 and the corner portion 14, the object to be conveyed tends to move forward due to inertia. Therefore, the force acting obliquely forward and downward more easily acts on the corner portion 14 from the two front idler wheels 40.
[0041] On the other hand, as a reaction force to the force acting on the corner portion 14 from the two front idler wheels 40, a reaction force RF1 acting obliquely rearward and upward acts on the two front idler wheels 40. This reaction force RF1 is a force that tries to push back the two front idler wheels 40 that are about to roll forward. As a component force of this reaction force RF1, a component force Fa acting upward and a component force Fb acting rearward act on the two front idler wheels 40. Due to the above-mentioned component force Fa, a force that raises the center axis CL1 of the support arm portion 42a and the rubber bush 43 in the direction in which they extend, that is, obliquely rearward and upward, is generated on the axle 41 of each front idler wheel 40.
[0042] Here, if there is no device to make it easier for the two front driven wheels 40 to overcome the step 12, it will be difficult for the two front driven wheels 40 to overcome the step 12. Further, as the step 12 becomes higher, it becomes more difficult for the two front driven wheels 40 to overcome the step 12.
[0043] In this regard, in the first embodiment, each of the two front driven wheels 40 and the two rear driven wheels 50 is attached to the cart main body 20 via the support member 42 and the rubber bush 43. Therefore, by the force that raises the axle 41 obliquely rearward and upward, each front driven wheel 40 is lifted while the elastic connecting portion 46 of each rubber bush 43 is elastically deformed in compression. Further, the above force is transmitted to the rear rubber bush 43 via the cart main body 20, and the elastic connecting portion 46 thereof is elastically deformed in compression.
[0044] Note that the cart main body 20 can swing along an arc centered on the axle 31 of the drive wheel 30. On the other hand, when the cart main body 20 is in a horizontal state, the direction in which each support arm portion 42a of the front support member 42 extends and the direction in which the central axis CL1 of the rubber bush 43 extends are inclined with respect to the vertical plane so as to be located more forward at the lower side. The direction in which each support arm portion 42a of the rear support member 42 extends and the direction in which the central axis CL1 of the rubber bush 43 extends are inclined with respect to the vertical plane so as to be located more rearward at the lower side. These directions are the directions along the above arc. Therefore, when the cart main body 20 swings, a force in the direction of elastically deforming the elastic connecting portion 46 of the rubber bush 43 from the front driven wheel 40 is likely to be applied. Further, a force in the direction of elastically deforming the elastic connecting portion 46 of the rear rubber bush 43 from the cart main body 20 is likely to be applied.
[0045] Furthermore, as shown in FIG. 3, as the elastic body, a rubber bush 43 is used in which a first adhered portion 44 and a second adhered portion 45 are connected by an elastic connecting portion 46 made of rubber. Therefore, even if the direction of the load input to the rubber bush 43 changes, the load easily acts on the elastic connecting portion 46. Regardless of the change in the direction of the input load, the elastic connecting portion 46 is easily compressed.
[0046] On the other hand, the drive wheel 30 and both rear driven wheels 50 are in contact with the general road surface 11. Therefore, as shown in FIG. 5, as the two front driven wheels 40 are lifted, the cart main body 20 is inclined with respect to the horizontal plane so as to be lower toward the rear side. Since the center of gravity of the carrier cart CC in which the cart main body 20 is inclined upward to the front is located behind the center of gravity of the carrier cart CC in which the cart main body 20 is in a horizontal state, the two front driven wheels 40 are more likely to lift off.
[0047] Here, let the dimension from the lowest point of the wheel to the top surface 13 of the step 12 be the engagement margin (lap margin) Δh. As the above-mentioned lifting and floating occur, as shown in FIGS. 5 and 6, the engagement margin Δh with respect to the top surface 13 of the two front driven wheels 40 becomes smaller. As the engagement margin Δh becomes smaller, the force (driving force of the drive wheel 30) required for the two front driven wheels 40 to cross the step 12 becomes smaller, and the two front driven wheels 40 can more easily cross the step 12.
[0048] Also, the angle formed by the cart main body 20 with respect to the horizontal plane increases as the front driven wheel 40 is lifted and as it floats, that is, as the engagement margin Δh becomes smaller.
[0049] Therefore, even if the drive wheel 30 is rotated with a small driving force, it is possible to cause the two front driven wheels 40 to cross the step 12. As described above, such crossing of the step 12 is possible even if the wheel diameter of the front driven wheel 40 is small.
[0050] As shown in FIGS. 6 and 7, when both front driven wheels 40 ride onto the top surface 13 of the step 12, that is, when passing over (crossing) the corner portion 14, the reaction force RF1 (see FIG. 4) no longer acts on the front driven wheels 40.
[0051] With respect to the cart main body 20, a repulsive force directed obliquely rearward and upward by the front rubber bush 43 and a repulsive force directed obliquely forward and upward by the rear rubber bush 43 act. That is, both the front and rear rubber bushes 43 attempt to lift the cart main body 20.
[0052] While both front driven wheels 40 are in contact with the top surface 13 of the step 12, the drive wheel 30 and both rear driven wheels 50 still remain in contact with the general road surface 11. The top surface 13 is located at a higher position than the general road surface 11. The cart main body 20 maintains an inclined state (front-rising inclined state) with respect to the horizontal plane such that it becomes lower toward the rear side.
[0053] When the drive wheel 30 continues to rotate forward and downward (counterclockwise), the both front driven wheels 40 and both rear driven wheels 50 rotate forward and downward in conjunction with the rotation. The carry cart CC travels forward with the cart main body 20 inclined with respect to the horizontal plane as described above.
[0054] Due to the travel of the carry cart CC, as shown in FIG. 7, the drive wheel 30 contacts the corner portion 14 on the rear side of the step 12 from the rear. At this time, due to the repulsive forces of the front and rear rubber bushes 43 described above and the rotational force of the drive wheel 30, the drive wheel 30 is lifted while in contact with the corner portion 14. This lifting is performed even when the drive wheel 30 is rotated with a small driving force.
[0055] With the above-mentioned lifting, as shown in FIG. 8, the engagement margin Δh of the drive wheel 30 with respect to the top surface 13 becomes smaller. As the engagement margin Δh becomes smaller, the force required for the drive wheel 30 to cross over the step 12 becomes smaller, and it becomes easier for the drive wheel 30 to cross over the step 12.
[0056] As shown in Fig. 9, the drive wheel 30 rides over the corner 14 and, as shown in Fig. 10, rides over the top surface 13 of the step 12. When the drive wheel 30 continues to rotate in the front-lower direction (counterclockwise), the two front driven wheels 40 and the two rear driven wheels 50 rotate in the front-lower direction in conjunction with its rotation. The carry cart CC travels forward with the cart main body 20 inclined with respect to the horizontal plane as described above.
[0057] Due to the travel of the carry cart CC, as shown in Fig. 10, the two rear driven wheels 50 come into contact with the corner 14 on the rear side of the step 12 from the rear. At this time, unlike the case where the two front driven wheels 40 come into contact with the corner 14, a force acting obliquely upward in the front acts on the two rear driven wheels 50. This is because, as shown in Fig. 4, when the two front driven wheels 40 come into contact with the corner 14 of the step 12, the cart main body 20 is not inclined. In contrast, as shown in Fig. 10, when the two rear driven wheels 50 come into contact with the corner 14, the cart main body 20 is inclined with respect to the horizontal plane so that it becomes lower toward the rear side.
[0058] Therefore, the two rear driven wheels 50 can overcome the step 12 with a smaller force than when the two front driven wheels 40 overcome the step 12. Also, due to the above-mentioned propulsive force generated with the rotational drive of the drive wheel 30, a force pulling the two rear driven wheels 50 forward acts on them. By this force, the two rear driven wheels 50 rotate in the front-lower direction and, as shown in Figs. 11 and 12, overcome the corner 14 of the step 12 and ride over the top surface 13. Then, the two front driven wheels 40, the drive wheel 30, and the two rear driven wheels 50 are all in contact with the top surface 13 of the step 12, that is, the cart main body 20 is in a horizontal state. The center of gravity of the carry cart CC moves forward as the inclination of the cart main body 20 with respect to the horizontal plane decreases. As shown in Fig. 12, when the cart main body 20 becomes horizontal, the center of gravity is located at the central portion of the carry cart CC in the front-rear direction.
[0059] Incidentally, when the front idler wheel 40 comes into contact with a new convex step while the carrier cart CC continues to run along the top surface 13, all the wheels can overcome this new step in the same manner as when overcoming the step 12 from the general road surface 11 as described above.
[0060] <Effects of the First Embodiment> (1-1) As shown in FIG. 1, in the first embodiment, the drive wheels 30 are attached to the cart main body 20 via intervening members (support member 33, attachment member 32, fastening member 37, etc.). On the other hand, both front idler wheels 40 and both rear idler wheels 50 are attached to the cart main body 20 via rubber bushes 43 having elasticity respectively.
[0061] Therefore, when both front idler wheels 40 overcome the step 12, the front and rear rubber bushes 43 are compressed, the horizontally positioned cart main body 20 tilts forward upward, and the center of gravity of the carrier cart CC moves rearward. Accordingly, even if the drive wheels 30 are rotated with a small driving force, both front idler wheels 40 can be made to overcome the step 12.
[0062] Also, when the drive wheels 30 overcome the step 12, the drive wheels 30 are lifted in a state of being in contact with the corner portion 14 by the repulsive force of each rubber bush 43 and the rotational force of the drive wheels 30. Therefore, even if the driving force of the drive wheels 30 is small, the step 12 can be overcome.
[0063] Furthermore, when both rear idler wheels 50 overcome the step 12, the cart main body 20 is in a forward upward inclined state, and a force acting obliquely forward upward acts on both rear idler wheels 50. Accordingly, also at this time, both rear idler wheels 50 can be made to overcome the step 12 with a small driving force.
[0064] And by both rear idler wheels 50 overcoming the step 12, the cart main body 20 can be returned to a horizontal state, and the center of gravity of the carrier cart CC can be moved forward from when the cart main body 20 is in a forward upward inclined state and returned to the central portion in the front-rear direction.
[0065] Even when the wheel diameters of the front driven wheels 40 and the rear driven wheels 50 are set to small values, by adding an elastic body (rubber bush 43), it becomes easier to overcome the step 12.
[0066] Also, by reducing the diameter, it is possible to reduce the weight and size of both the front driven wheels 40 and the rear driven wheels 50, and thus, the carry cart CC. Furthermore, when the carry cart CC is viewed from the front and the rear, since the front driven wheels 40 and both rear driven wheels 50 have small diameters, they are less conspicuous than when they have large diameters. Therefore, the appearance of the carry cart CC can be improved when viewed from the front or the rear.
[0067] (1-3) As shown in FIG. 2, the drive wheel 30 is attached to the cart main body 20 via an intervening member (support member 33, attachment member 32, bolts 34, nuts 35, and fastening member 37) constituted by a rigid body. Therefore, the cart main body 20 can be swung like a seesaw, a toy "yajirobe", etc. along an arc centered on the axle 31 of the drive wheel 30. As a result, the effect of the above (1-1) can be further exerted.
[0068] (1-4) As shown in FIG. 1, in the first embodiment, when the cart main body 20 is in a horizontal state, the central axis lines CL1 of the respective support arm portions 42a and the rubber bushes 43 in the front support member 42 are inclined with respect to the vertical plane so that they are positioned more forward toward the lower side. Also, the central axis lines CL1 of the respective support arm portions 42a and the rubber bushes 43 in the rear support member 42 are inclined with respect to the vertical plane so that they are positioned more rearward toward the lower side. Therefore, it is advantageous in the following points as compared with the case where the extending directions of the respective support arm portions 42a and the central axis line CL1 are parallel to the vertical plane.
[0069] · When the cart main body 20 swings, a force in the direction of causing compressive elastic deformation is likely to be applied to the front rubber bush 43 from each front driven wheel 40. · Also, when the cart main body 20 swings, a force in the direction of causing compressive elastic deformation is likely to be applied to the rear rubber bush 43 from the cart main body 20.
[0070] (1-5) As shown in FIG. 3, a rubber bush 43 having an elastic connecting portion 46 is used as the elastic body. Therefore, even when the direction of the load input to the rubber bush 43 changes, the load is likely to act on the elastic connecting portion 46 which is the elastic part. Regardless of the change in the direction of the input load, the elastic connecting portion 46 is likely to be compressed. It is possible to suppress a large change in the biasing force (repulsive force) of the elastic connecting portion 46 due to the change in the direction of the input load.
[0071] (Second Embodiment) Next, a second embodiment of the carry cart will be described with reference to FIG. 13. The second embodiment is different from the first embodiment in that a spring is used instead of the rubber bush 43 as the elastic body.
[0072] <Mounting Structure of Each Front Idler Wheel 40> Each front idler wheel 40 is attached to the cart main body 20 via a support member 42, a shaft 55, and a spring disposed below it.
[0073] As the support member 42, one having the same structure as that described in the first embodiment is used. Each support arm portion 42a of the support member 42 is inclined with respect to the vertical plane so that it is located more forward at the lower side when the cart main body 20 is in a horizontal state, similar to the first embodiment. The axle 41 of the front idler wheel 40 disposed between both support arm portions 42a is rotatably supported with respect to the bearing holes 48 of both support arm portions 42a.
[0074] The shaft 55 is disposed in an inclined state with respect to the vertical plane so that it is located more forward at the lower side. The upper end portion of the shaft 55 is fixed to the cart main body 20. The lower end portion of the shaft 55 is inserted through the connecting plate portion 42b of the support member 42 so as to be movable in the length direction of the shaft 55.
[0075] As the spring, a coil spring 56 is used. The coil spring 56 is disposed in a compressed state between the cart main body 20 and the connecting plate portion 42b around the shaft 55. The central axis CL2 of the coil spring 56 is inclined with respect to the vertical plane so as to be positioned more forward toward the lower side.
[0076] <Attachment structure of each rear driven wheel 50> Each rear driven wheel 50 is attached to the cart main body 20 via a support member 42, a shaft 55, and a coil spring 56 disposed below it. As the support member 42, the shaft 55, and the coil spring 56, those having the same configuration as those used in the attachment structure of each front driven wheel 40 described above are used.
[0077] The central axis CL2 of each support arm portion 42a of the support member 42, the shaft 55, and the coil spring 56 is inclined with respect to the vertical plane so as to be positioned more rearward toward the lower side when the cart main body 20 is in a horizontal state.
[0078] The configuration other than the above is the same as that of the first embodiment. Therefore, the same reference numerals are given to the same elements as those described in the first embodiment, and the overlapping description is omitted. In the second embodiment, the coil spring 56 elastically deforms (expands and contracts) instead of the rubber bush 43. Therefore, according to the second embodiment, among the effects of the first embodiment, the effects excluding the above (1-5) specific to the rubber bush 43, in this case, the same effects as the above (1-1) to (1-4) can be obtained.
[0079] (Third Embodiment) Next, a third embodiment of the carrier cart will be described with reference to FIGS. 14 and 15.
[0080] The third embodiment is different from the second embodiment in that a leaf spring 61 is used as the spring instead of the coil spring 56. <Attachment structure of each front driven wheel 40> Each front follower wheel 40 is attached to the cart main body 20 via a support member 42 and a leaf spring 61 disposed below it.
[0081] As the support member 42, one having the same structure as that described in the first and second embodiments is used. Each support arm portion 42a of the support member 42 is inclined with respect to the vertical plane so that it is positioned more forward at the lower side when the cart main body 20 is in a horizontal state, similar to the first and second embodiments. The axle 41 of the front follower wheel 40 disposed between both support arm portions 42a is rotatably supported with respect to the bearing holes 48 of both support arm portions 42a.
[0082] The leaf spring 61 includes an upper plate portion 61a, a lower plate portion 61b, and a connecting plate portion 61c having the same width in the left - right direction. Such a leaf spring 61 is formed, for example, by bending a strip - shaped spring steel material.
[0083] The upper plate portion 61a is disposed below the cart main body 20 in an inclined state where it becomes lower toward the rear side. The upper plate portion 61a is attached to the cart main body 20 from below by fastening using a fastening member 62 such as a screw. The lower plate portion 61b is below the upper plate portion 61a and is disposed parallel to or in a state close to being parallel to the upper plate portion 61a. Therefore, the lower plate portion 61b is inclined so that it becomes lower toward the rear side. The connecting plate portion 61c connects the front end portion of the upper plate portion 61a and the front end portion of the lower plate portion 61b. The connecting plate portion 61c is curved in an arc shape so as to bulge obliquely forward and upward.
[0084] The lower plate portion 61b of the leaf spring 61 is adjacent to the front side of the connecting plate portion 42b of the support member 42 and is connected to the connecting plate portion 42b. In the third embodiment, the leaf spring 61 is integrally formed with the support member 42.
[0085] <Attachment structure of each rear follower wheel 50> Each rear driven wheel 50 is attached to the cart main body 20 via a support member 42 and a leaf spring 61 disposed below it. As the support member 42 and the leaf spring 61, those having the same configuration as those used in the attachment structure of each of the front driven wheels 40 described above are used.
[0086] Each support arm portion 42a of the support member 42 is inclined with respect to the vertical plane so that when the cart main body 20 is in a horizontal state, they are all located more rearward toward the lower side. The upper plate portion 61a of the leaf spring 61 is disposed below the cart main body 20 in an inclined state such that it becomes higher toward the rear side. The lower plate portion 61b is located below the upper plate portion 61a and is disposed parallel to or in a state close to being parallel to the upper plate portion 61a. Therefore, the lower plate portion 61b is inclined so that it becomes higher toward the rear side. The connecting plate portion 61c connects the rear end portion of the upper plate portion 61a and the rear end portion of the lower plate portion 61b. The connecting plate portion 61c is curved in an arc shape so as to bulge obliquely rearward and upward.
[0087] The lower plate portion 61b of the leaf spring 61 is adjacent to the rear side of the connecting plate portion 42b of the support member 42 and is connected to the connecting plate portion 42b. In the third embodiment, the leaf spring 61 is integrally formed with the support member 42.
[0088] The configuration other than the above is the same as that of the first and second embodiments. Therefore, the same reference numerals are given to the same elements as those described in the first and second embodiments, and redundant explanations are omitted. In the third embodiment, instead of the rubber bush 43, the leaf spring 61, particularly the connecting plate portion 61c that is curved in an arc shape, elastically deforms and elastically restores. Therefore, according to the third embodiment, among the effects of the first embodiment, the effects excluding the above (1-5) specific to the rubber bush 43, in this case, the same effects as the above (1-1) to (1-4) can be obtained. In addition, according to the third embodiment, the following effects can also be obtained.
[0089] (3-1) The support member 42 and the leaf spring 61 are integrally formed. Therefore, the number of parts of the carrier cart CC can be reduced compared to the case where the support member 42 and the leaf spring 61 are constituted by separate members.
[0090] <Modified Example> Each embodiment can be implemented with the following modifications. Each embodiment and the following modified examples can be implemented in combination with each other within a technically non - conflicting range.
[0091] [Matters regarding the cart main body 20] · On the condition that it is arranged above the grounding points of each of the two front driven wheels 40, the drive wheel 30, and the two rear driven wheels 50 with respect to the road surface 10, the vertical position where the cart main body 20 is arranged may be changed. For example, the lower surface 21 of the cart main body 20 may be located at a position higher than the lowermost end and lower than the uppermost end of each of the two front driven wheels 40, the drive wheel 30, and the two rear driven wheels 50.
[0092] · The cart main body 20 may be provided with a seat on which the user of the carrier cart CC sits or a shopping basket. Further, the cart main body 20 may be provided with a structure for detachably attaching the shopping basket. Furthermore, the cart main body 20 may be provided with a place for hanging bags such as a handbag and a bag.
[0093] [Matters regarding the wheels] · The front driven wheels 40 may be arranged at a plurality of positions in the front - rear direction in the region in front of the drive wheel 30.
[0094] · The rear driven wheels 50 may be arranged at a plurality of positions in the front - rear direction in the region behind the drive wheel 30. · The drive wheel 30 may be arranged at a plurality of positions in the front - rear direction or at a plurality of positions in the left - right direction in the region between the front driven wheels 40 and the rear driven wheels 50.
[0095] In this case, the number of at least one of the front driven wheels 40 and the rear driven wheels 50 may be changed to "1". · The number of the front driven wheels 40 arranged in the left - right direction at the same position in the front - rear direction may be 3 or more. Similarly, the number of the rear driven wheels 50 arranged in the left - right direction at the same position in the front - rear direction may be 3 or more.
[0096] · The drive wheel 30 may be rotationally driven by a motor provided outside instead of inside the drive wheel 30. · The drive wheel 30 may be rotationally driven by a power source other than the motor.
[0097] · The wheel diameter of the rear driven wheel 50 may be the same as or different from the wheel diameter of the front driven wheel 40. · At least one of the front driven wheel 40, the drive wheel 30, and the rear driven wheel 50 may be constituted by a caster with a stopper (with a brake).
[0098] [Matters regarding the intervening member] · As the intervening member, a member different from those in the above - mentioned embodiments may be used, and the drive wheel 30 may be attached to the cart main body 20 via this member.
[0099] · The intervening member interposed between the drive wheel 30 and the cart main body 20 may be formed of a material that is less likely to elastically deform than the elastic body disposed between the front driven wheel 40 and the cart main body 20, or the elastic body disposed between the rear driven wheel 50 and the cart main body 20. The intervening member may be constituted by, for example, an elastic body harder than the above - mentioned elastic body. Also, the intervening member may be deformed by a member that is extremely difficult to elastically deform or a member that does not elastically deform.
[0100] [Matters regarding the elastic body] · As the elastic body disposed between the front driven wheel 40 and the cart main body 20 and the elastic body disposed between the rear driven wheel 50 and the cart main body 20, different types of elastic bodies may be used.
[0101] · In the third embodiment, the location where the upper plate portion 61a and the lower plate portion 61b of the leaf spring 61 disposed between the rear driving wheel 40 and the cart main body 20 are connected by the connecting plate portion 61c may be changed to a location different from the front end portion.
[0102] Similarly, in the leaf spring 61 disposed between the rear driving wheel 50 and the cart main body 20, the location where the upper plate portion 61a and the lower plate portion 61b are connected by the connecting plate portion 61c may be changed to a location different from the rear end portion.
[0103] · In the third embodiment, the support member 42 and the leaf spring 61 may be constituted by separate members. · As the elastic body, an elastic body different from those used in the first to third embodiments may be used. For example, the elastic body may be constituted by a spring of a type different from the coil spring 56 and the leaf spring 61.
[0104] [Others] · In order to support the axles 31, 41, 51 by the support members 33, 42, instead of the bearing holes 36, 48, for example, notches extending upward from the lower end surfaces of the respective support arm portions 33a, 42a may be formed on the support arm portions 33a, 42a. Then, the axles 31, 41, 51 may be rotatably engaged with these notches.
[0105] · The carrier cart CC of each of the above embodiments is considered not suitable for a so-called non-self-propelled carrier cart CC that is pushed and run by a person for the following reasons. When applied to a non-self-propelled carrier cart CC, the drive wheel 30 is changed to a wheel that is not rotationally driven by a power source. When running, the user of the non-self-propelled carrier cart CC grips the handle provided on the non-self-propelled carrier cart CC and pushes it forward. This handle is provided at a height that can be grasped by a standing user. Therefore, the handle is usually located at a position far above the wheels.
[0106] Therefore, in order to drive the carrier cart CC with the front idler wheel 40 in contact with the step 12, when the user grips and pushes the steering wheel, the cart body 20 tends to tilt forward and downward. This is because it is difficult to make the carrier cart CC move like a seesaw or a rocking horse.
[0107] · The carrier cart CC may be provided with a braking mechanism for stopping the running. Further, the carrier cart CC may be provided with a brake for keeping the carrier cart CC in a stopped state during parking. In the case of the carrier cart CC provided with a seat portion, the carrier cart CC may be provided with a brake for keeping the carrier cart CC in a stopped state when sitting on the seat portion.
Explanation of Reference Numerals
[0108] 10…Road surface 20…Cart body 30…Drive wheel (wheel) 31, 41, 51…Axle 32…Attachment member (intervening member, rigid body) 33…Support member (intervening member, rigid body) 34…Bolt (intervening member, rigid body) 35…Nut (intervening member, rigid body) 37…Fastening member (intervening member, rigid body) 40…Front idler wheel (wheel) 42…Support member 43…Rubber bush (elastic body) 44…First adherend 45…Second adherend 46…Elastic connection part 50…Rear idler wheel (wheel) 56…Coil spring (elastic body) 61…Leaf spring (elastic body) CC…Carrier cart
Claims
1. A carrier cart that rolls on a road surface by rotating about an axle, comprising: a wheel that rolls on the road surface by rotating about the axle; and a cart body portion that is disposed above a ground contact portion of the wheel with respect to the road surface and on which an object to be conveyed is placed. The wheel includes a drive wheel that is rotationally driven by a power source, a front driven wheel that is disposed in front of the drive wheel, and a rear driven wheel that is disposed behind the drive wheel. The drive wheel is attached to the cart body portion via an intervening member. The front driven wheel and the rear driven wheel are each attached to the cart body portion via an elastic body.
2. The carrier cart according to claim 1, wherein the intervening member is formed of a rigid body.
3. Axles of the front driven wheel and the rear driven wheel are rotatably supported by support members. The elastic body includes a rubber bush. The rubber bush includes a first adhered portion attached to the cart body portion, a second adhered portion attached to the support member, and an elastic connecting portion that is formed of rubber so as to be elastically deformable and that connects the first adhered portion and the second adhered portion. The carrier cart according to claim 1 or claim 2.
Citation Information
Patent Citations
JP1975000662U
Suspension device for conveying truck
JP1993170102A
Handcart conveying device and handcart conveying body
JP2006076468A