Carry cart

Abstract

To enable front wheels to climb over a step without using auxiliary wheels.SOLUTION: A carry cart CC includes wheels each of which rolls over a road surface 10 due to rotation with an axle as a center, and a cart body 20 disposed above a grounding level at which the wheels are in contact with the road surface 10. Further, the carry cart includes a support part 41, a link body 51, and an elastic body 63. The support part 41 is interposed between a front wheel 31 and a rear wheel 33. A skeleton part of the support part is formed with a support body 42. The link body 51 supports an axle 32 of the front wheel 31, and turns in a vertical direction with a turning axis line AL1, which is set at a point behind the axle 32 and ahead of the support body 42, as a center. The elastic body 63 is interposed between the link body 51 and the support body 42, and causes a constraining force to act on the link body 51 above the turning axis line AL1. When both the front wheel 31 and the rear wheel 33 are grounded on a horizontal surface, the turning axis line AL1 is located at a point lower than a center axis line AL2 of the axle 32.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a carry cart that has wheels that rotate about axles to roll on a road surface, and a cart body on which transported items such as luggage can be placed, and that runs by the rolling of the wheels. [Background technology]

[0002] In the field of carry carts, various structures have been proposed for enabling wheels to overcome convex steps. For example, in the walking aid described in Patent Document 1, main wheels corresponding to the front wheels are provided, and auxiliary wheels are provided in front of the main wheels in the direction of travel. The contact surface of the auxiliary wheels is set above the contact surface of the main wheels. A link mechanism is interposed between the auxiliary wheels and the main wheels. When the main wheels come into contact with a step, they are moved rearward and upward in the direction of travel. This movement reduces the impact when the main wheels come into contact with the step. In addition, the movement of the main wheels is transmitted to the auxiliary wheels via the link mechanism, and the auxiliary wheels are rotated downward. The auxiliary wheels come into contact with the top surface of the step and hold down the top surface, thereby preventing the walking aid from tipping forward.

[0003] When the main wheels overcome the step, the auxiliary wheels are rotated upward by the elastic bodies and return to their original positions, and the walking aid returns to the same position as before the step was overcome. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2006-306246 A Summary of the Invention [Problem to be solved by the invention]

[0005] The technology described in the above Patent Document 1 requires auxiliary wheels to allow the main wheels (front wheels) to overcome steps. However, there is a demand for a carry cart that allows the front wheels to overcome steps without using such auxiliary wheels. [Means for solving the problem]

[0006] A carry cart for solving the above problem comprises wheels that roll on a road surface by rotating around their axles, and a cart main body on which a transported object is placed and which is positioned above the points where the wheels contact the road surface, the wheels comprising front wheels and rear wheels positioned rearward of the front wheels in the direction of travel, and the carry cart runs by the rolling of the wheels, the carry cart comprising: a support section that is provided between the front and rear wheels in the direction of travel and at least the skeletal portion is constituted by a support main body section; a link section that supports the axle of the front wheels and rotates in the vertical direction around a rotation axis that is set at a position rearward of the axle of the front wheels and forward of the support main body section; and an elastic section that is located between the link section and the support main body section and above the rotation axis, which applies a biasing force to the link section, and when both the front wheels and the rear wheels are in contact with a horizontal surface, the rotation axis is located at a position lower than the central axis of the axle of the front wheels. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram showing a first embodiment of the carry cart, and is a schematic side view of the carry cart before a front wheel comes into contact with a step. [Diagram 2] FIG. 2 is a schematic side view of the carry cart in the first embodiment, in which a front wheel comes into contact with a rear corner of a step. [Diagram 3] FIG. 2 is a schematic side view of the carry cart in the first embodiment, in which a front wheel is being lifted. [Figure 4] FIG. 2 is a schematic side view of the carry cart in the first embodiment, in which the front wheels are further raised. [Diagram 5]FIG. 2 is a schematic side view of the carry cart in the first embodiment, in which a front wheel is passing a corner. [Figure 6] FIG. 2 is a schematic side view of the carry cart in the first embodiment, in which the front wheels roll on the top surface of a step. [Figure 7] FIG. 2 is a schematic side view of the carry cart in the first embodiment, in which a rear wheel comes into contact with a rear corner of a step. [Figure 8] FIG. 2 is a schematic side view of the carry cart in the first embodiment, in which a rear wheel is being lifted. [Figure 9] FIG. 2 is a schematic side view of the carry cart in the first embodiment, in which the rear wheels roll on the top surface of a step together with the front wheels. [Figure 10] FIG. 13 is a schematic partial side view of the carry cart according to a second embodiment, in which the front wheels are in contact with the rear corner of the step. [Figure 11] FIG. 13 is a schematic partial side view of the carry cart according to a third embodiment, in which the front wheels come into contact with the rear corner of the step. [Figure 12] 12 is a perspective view of a link portion and an elastic portion in FIG. 11. [Figure 13] FIG. 13 is a partial perspective view showing a modified example of the lower part of the carry cart. [Figure 14] FIG. 14 is a partial side view of the lower part of the carry cart of FIG. 13. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, a first embodiment of the carry cart will be described with reference to FIGS. As shown in FIG. 1, the carry cart CC includes a plurality of wheels that rotate about their axles to roll on a road surface 10, and a cart body 20 on which an object to be carried, such as luggage (not shown), can be placed.

[0009] The wheels include a single front wheel 31 and a pair of rear wheels 33 (only one of the rear wheels 33 is shown in each drawing). The carry cart CC travels from right to left in each drawing by the above-mentioned rolling of each wheel.

[0010] In the following description, the forward direction of the carry cart CC is defined as the front, and the backward direction is defined as the rear. The up-down direction refers to the up-down direction of the carry cart CC, and the left-right direction refers to the direction perpendicular to both the forward direction and the up-down direction. The left-right direction refers to the width direction of the carry cart CC, and coincides with the left-right direction when the carry cart CC is moving forward.

[0011] <Road surface 10> The road surface 10 on which the carry cart CC travels has a convex step 12. In order to distinguish the convex step 12 from other parts of the road surface 10, the latter will be referred to as a general road surface 11. The top surface of the step 12 will be referred to as a top surface 13, and the upper rear corner of the step 12 will be referred to as a rear corner 14. For ease of explanation, it is assumed here that the general road surface 11 and the top surface 13 are both horizontal surfaces.

[0012] The top surface 13 is formed, for example, by the upper surface of a sidewalk. The general road surface 11 is formed, for example, by the upper surface of a roadway. The vertical dimension (height) of the step 12, that is, the difference in height between the general road surface 11 and the top surface 13, is 30 mm or less, and is assumed to be about 20 mm in the first embodiment.

[0013] <Cart body 20> The cart body 20 is disposed above the points where the front wheels 31 and the rear wheels 33 contact the road surface 10. In the first embodiment, the cart body 20 is disposed at a higher position than the front wheels 31 and the rear wheels 33. Note that in each drawing, the cart body 20 is illustrated in a simplified form.

[0014] <Wheels> The front wheel 31 is disposed in the left-right central portion of the space below the front of the cart body 20. The front wheel 31 is driven to rotate about a central axis AL2 of an axle 32 by a motor (not shown) serving as a power source. The motor is operated by receiving power from a battery (not shown) mounted on the cart body 20 or the like.

[0015] The central axis AL2 extends in the left-right direction. The front wheels 31 are driven wheels that are rotated to provide the cart body 20 with a propulsive force for traveling. As the motor, for example, an electric motor of a type that is disposed inside or near the front wheels 31 and transmits power to the front wheels 31 to directly rotate the front wheels 31, that is, a so-called in-wheel motor, may be used. Both ends of the axle 32 protrude outward on both sides in the left-right direction from the front wheels 31.

[0016] Generally, a wheel can overcome a step 12 if the height of the step 12 is up to about 55% of the radius of the wheel. From this perspective, in the first embodiment, the front wheel 31 has a wheel diameter of about 100 mm.

[0017] The pair of rear wheels 33 are disposed in the space below the cart main body 20, further rearward in the direction of travel than the front wheels 31. Unlike the front wheels 31, the rear wheels 33 are driven wheels that do not generate driving force. The rear wheels 33 have a wheel diameter (diameter) similar to that of the front wheels 31. The rear wheels 33 are disposed at positions spaced apart from each other in the left-right direction. Each rear wheel 33 is rotatable about an axle 34 extending in the left-right direction. Both ends of each axle 34 protrude outward on both sides in the left-right direction from the rear wheels 33.

[0018] The carry cart CC further includes a support portion 41, a link portion, and an elastic portion. Next, each portion will be described. <Support part 41> The support part 41 is provided between the front wheels 31 and both rear wheels 33 in the traveling direction. In the first embodiment, the support part 41 is disposed in the center part in the front-rear direction and in the center part in the left-right direction of the space below the cart main body 20. The support part 41 is disposed in its entirety in the space below the cart main body 20. The support part 41 includes a support main body part 42 and a pair of front support plates 43, and also includes a pair of rear wheel support parts 45 for each rear wheel 33.

[0019] The support body 42 constitutes a framework of the support part 41. The support body 42 extends downward from the cart body 20. An upper end of the support body 42 is fixed to the cart body 20.

[0020] The pair of front support plates 43 are spaced apart from each other in the left-right direction. Most or all of both front support plates 43 are arranged at an incline with respect to the horizontal plane so as to become lower toward the front at a location adjacent to the front side of the support body 42. The rear upper end portion of each front support plate 43 is fixed to the lower end portion of the support body 42.

[0021] The pair of rear wheel support parts 45 for each rear wheel 33 are spaced apart from each other in the left-right direction. Most or all of the two rear wheel support parts 45 are disposed adjacent to the rear side of the support body part 42. In FIG. 1 and the like, each rear wheel support part 45 is disposed in a state inclined with respect to the horizontal plane so as to be lower toward the rear side, but it may be disposed in a state inclined in the opposite direction or horizontally. Each rear wheel support part 45 is fixed at its front end to the lower end part of the support body part 42. The rear parts of the pair of rear wheel support parts 45 for each rear wheel 33 sandwich the rear wheel 33 from both sides in the left-right direction. The rear ends of the pair of rear wheel support parts 45 sandwiching the rear wheel 33 support the rear wheel 33 rotatably by the axle 34. That is, a bearing hole is formed in the rear end part of each rear wheel support part 45, and the parts of the axle 34 protruding outward from the rear wheel 33 on both sides in the left-right direction are inserted into the bearing hole.

[0022] <Link section> In the first embodiment, the link portion is constituted by a link body 51. The link body 51 has a function of supporting the front wheel 31 on the support portion 41. The link body 51 has two combinations of a front link portion 52 and a rear link portion 53 arranged adjacent to the rear side of the front link portion 52. Although not shown, both combinations are arranged spaced apart in the left-right direction. The rear link portions 53 of each combination are connected by a connecting portion (not shown) extending in the left-right direction. The front portions of the pair of front link portions 52 sandwich the front wheel 31 from both sides in the left-right direction.

[0023] When the front wheels 31 and both rear wheels 33 are in contact with a horizontal surface, for example, the general road surface 11, the front link portion 52 of each combination is inclined relative to the general road surface 11 so as to be lower toward the front. The rear link portion 53 of each combination is inclined relative to the general road surface 11 so as to be lower toward the rear. The rear link portion 53 of each combination is connected at its front end to the rear end of the front link portion 52. In other words, the front link portion 52 and the rear link portion 53 of each combination are connected in a bent state. The front end portion of each front link portion 52 constitutes the front end portion of the link body 51. The rear end portion of each rear link portion 53 constitutes the rear end portion of the link body 51.

[0024] A part of the link body 51, which is the front end in the first embodiment, supports the axle 32 of the front wheel 31. That is, bearing holes are formed in the front ends of both front link parts 52, and the parts of the axle 32 that protrude outward on both sides in the left-right direction from the front wheel 31 are inserted into the bearing holes.

[0025] Further, the link body 51 is rotatable in the vertical direction around the rotation axis AL1. The rotation axis AL1 is set at a location rearward of the axle 32 and forward of the support body 42. In the first embodiment, a support shaft 44 having the rotation axis AL1 as its axis is disposed at the location. The link body 51 is supported at its rear end, i.e., at the rear end of each of the rear link portions 53, by the support shaft 44 so as to be rotatable in the vertical direction relative to the front end portions of the front support plates 43.

[0026] <Elastic part> The elastic portion is located between the link body 51 and the support main body portion 42, and serves to apply a biasing force to the link body 51 above the rotation axis AL1.

[0027] More specifically, a spring bearing 61 is disposed between the link body 51 and the support main body 42, at a location rearward of the boundary portion 54 between the front link portion 52 and the rear link portion 53. The spring bearing 61 includes a bearing portion 61a attached to the support main body 42, and a shaft 61b extending from the bearing portion 61a toward the boundary portion 54 of the link body 51. A front end portion of the shaft 61b is inserted into the connecting portion of the link body 51 so as to be movable relative to the connecting portion. Due to this insertion, the shaft 61b is supported by the connecting portion without interfering with the rotation of the link body 51 about the rotation axis AL1 of the support shaft 44.

[0028] The elastic portion is configured by an elastic body 63 arranged between the link body 51 and the support main body 42 above the support shaft 44. In the first embodiment, a coil spring is used as the elastic body 63. The elastic body 63 is arranged around the shaft 61b between the boundary portion 54 and the receiving portion 61a. When compressed and elastically deformed, the elastic body 63 biases the link body 51 forward above the rotation axis AL1, here at the boundary portion 54. The direction in which the elastic body 63 biases the link body 51 is a direction in which the link body 51 rotates forward and downward about the rotation axis AL1.

[0029] <Vertical Positional Relationship Between the Central Axis AL2 and the Rotation Axis AL1> In the first embodiment, the vertical positional relationship between the pivot axis AL1 and the central axis AL2 is set so that when the front wheel 31 and both rear wheels 33 are in contact with a horizontal surface, such as the general road surface 11, the pivot axis AL1 is located at a lower position than the central axis AL2.

[0030] Next, the operation of the carry cart CC of the first embodiment configured as described above will be described with reference to Figures 1 to 9. It is assumed that an object to be carried is placed on the cart main body 20 of the carry cart CC.

[0031] As shown in FIG. 1, when the front wheels 31 and both rear wheels 33 are in contact with the general road surface 11 which is a horizontal plane, the cart body 20 (bottom surface) is in a horizontal state. 1, when the front wheel 31 is rotated forward and downward by the motor, a propulsive force for moving the carry cart CC forward is generated in the front wheel 31. A part of this propulsive force is transmitted to both rear wheels 33 via the link body 51, the front support plate 43, the support body 42, and the rear wheel support part 45. A part of the propulsive force is also transmitted to both rear wheels 33 via the link body 51, the elastic body 63, the spring receiver 61, the support body 42, and the rear wheel support part 45. The rear wheels 33 are pulled forward by the transmitted propulsive force and rotate forward and downward in conjunction with the front wheel 31.

[0032] The front wheels 31 and both rear wheels 33 roll forward on the general road surface 11. The carry cart CC runs (self-propels) forward along the general road surface 11 without changing the posture of the cart body 20 (without tilting).

[0033] As shown in FIG. 2, when the carry cart CC travels (self-propelled), the front wheel 31 comes into contact with the rear corner 14 of the step 12 from behind. This contact causes a force from the front wheel 31 to act on the step 12 in a diagonally forward and downward direction. In particular, since an object to be carried is placed on the cart body 20, when the forward travel of the carry cart CC is restricted by the contact of the front wheel 31 with the step 12, the object to be carried tries to move forward due to inertia. Therefore, the force acting diagonally forward and downward is more likely to act on the corner 14 from the front wheel 31. Meanwhile, as a reaction force to the above force, a reaction force RF1 acting diagonally upward and backward from the corner 14 acts on the front wheel 31. This reaction force RF1 is a force that tries to push back the front wheel 31 that tries to roll forward.

[0034] Here, if no measures are taken to make it easier for the front wheel 31 to overcome the step 12, it will be difficult for the front wheel 31 to overcome the step 12. In addition, as the step 12 becomes higher, it becomes more difficult for the front wheel 31 to overcome the step 12.

[0035] In this regard, according to the first embodiment in which the link body 51 is used as the link portion and the elastic body 63 is used as the elastic portion, the link body 51 attempts to rotate upward about the rotation axis AL1 due to the reaction force RF1 while compressing and elastically deforming the elastic body 63 backward. An upward force F1 acts on the front wheel 31 as shown in FIG.

[0036] 1, when the front wheel 31 rotating downward and forward comes into contact with the corner 14 of the step 12, a force acting diagonally downward and rearward acts from the front wheel 31 on the corner 14. As shown in Fig. 3, a reaction force RF2 of this force acts from the corner 14 on the front wheel 31. As components of this reaction force RF2, an upward component force Fa and a forward component force Fb in the traveling direction act on the front wheel 31.

[0037] Then, this upward component force Fa is added to the upward force F1 acting on the front wheels 31 as the link body 51 rotates, so that the front wheels 31 are lifted up. Meanwhile, both rear wheels 33 are still in contact with the general road surface 11. Therefore, as shown in Figures 3 and 4, the cart body 20 is inclined with respect to the horizontal plane so that the rear side is lower.

[0038] Here, the dimension from the lowest point of the front wheel 31 to the top surface 13 of the step 12 is defined as the overlap (lap) Δh. As the step is lifted, the overlap Δh becomes smaller, as shown in Figures 3 and 4. As the overlap Δh becomes smaller, the force required for the front wheel 31 to get over the step 12 becomes smaller. Unlike conventional carrier carts, the front wheel 31 can easily get over the step 12 without using auxiliary wheels.

[0039] 5, when the front wheel 31 runs over the step 12, that is, when it passes the corner 14, the reaction force RF1 (see FIG. 2) no longer acts on the front wheel 31. Due to the elastic restoring force of the elastic body 63, the link body 51 tries to rotate downward about the rotation axis AL1 as the center, as shown by the arrow in FIG. 5, and the front wheel 31 returns to the same state as before it ran over the step 12.

[0040] The front wheels 31 contact the top surface 13 of the step 12, and both rear wheels 33 still contact the general road surface 11. The front wheels 31 are positioned higher than the two rear wheels 33. The cart body 20 maintains an inclined state with respect to the horizontal plane so that the rear side is lower.

[0041] As shown in FIG. 6, when the front wheel 31 and both rear wheels 33 rotate forward and downward, the carry cart CC with the cart body 20 tilted relative to the horizontal plane as described above travels forward. As the carry cart CC travels, both rear wheels 33 come into contact with the rear corner 14 of the step 12 from behind as shown in FIG. 7. At this time, unlike the case where the front wheel 31 comes into contact with the step 12 as described above, a force acts on the rear wheel 33 in an obliquely forward and upward direction. This is because, as shown in FIG. 2, when the front wheel 31 comes into contact with the corner 14 of the step 12, the cart body 20 is not tilted. In contrast, as shown in FIG. 7, when the both rear wheels 33 come into contact with the corner 14, the cart body 20 is tilted relative to the horizontal plane so as to be lower toward the rear.

[0042] Therefore, as shown in Fig. 8, both rear wheels 33 can get over the step 12 with less force than when the front wheel 31 gets over the step 12. The propulsive force generated by the rotational driving of the front wheel 31 acts on both rear wheels 33 with a force pulling them forward. This force causes both rear wheels 33 to rotate forward and downward, and as shown in Fig. 9, when the step 12 is overcome, both the front wheel 31 and both rear wheels 33 come into contact with the top surface 13 of the step 12.

[0043] Furthermore, if the front wheel 31 comes into contact with a new convex step while the carry cart CC continues to run along the top surface 13, the front wheel 31 and both rear wheels 33 will overcome this new step in the same manner as when climbing over the step 12 from the general road surface 11.

[0044] Next, the effects of the first embodiment will be described. (1-1) As shown in Fig. 1, a support part 41 is provided between the front wheel 31 and both rear wheels 33 in the traveling direction. A link body 51 is used as the link part, and an elastic body 63 made of a coil spring is used as the elastic part. A support shaft 44 having a rotation axis AL1 as its own axis is used.

[0045] The link body 51 supports the axle 32 of the front wheel 31. The link body 51 is supported by the support shaft 44 so as to be rotatable in the vertical direction at a location (the front end of the front support plate 43) that is rearward of the axle 32 and forward of the support body 42 of the support part 41. This configuration enables the link body 51 to rotate in the vertical direction about the rotation axis AL1. An elastic body 63 is disposed between the link body 51 and the support body 42 above the support shaft 44. The elastic body 63 exerts a biasing force on the boundary portion 54 of the link body 51 above the rotation axis AL1. When both the front wheel 31 and the rear wheel 33 are in contact with the horizontal surface (general road surface 11), the rotation axis AL1 is positioned lower than the central axis AL2 of the axle 32.

[0046] Therefore, when the front wheel 31 comes into contact with the corner 14 of the step 12, a reaction force RF1 (see FIG. 2) acting diagonally upward and rearward is applied to the front wheel 31 from the corner 14, causing the link body 51 to rotate upward while compressing and elastically deforming the elastic body 63. An upward force F1 (see FIG. 3) is applied to the front wheel 31.

[0047] In addition, when the front wheel 31 rotating downward and forward comes into contact with the corner 14, a reaction force RF2 (see FIG. 3) directed obliquely upward and forward acts on the front wheel 31 from the corner 14. An upward component force Fa of this reaction force RF2 acts on the front wheel 31.

[0048] The force F1 and the component force Fa lift the front wheel 31, reducing the engagement allowance Δh and reducing the force required for the front wheel 31 to overcome the step 12. As a result, the front wheel 31 can overcome the step 12 without using auxiliary wheels.

[0049] (1-2) In the case of a type of carrier cart that is pushed forward by a person (non-self-propelled type), when the front wheels come into contact with a convex step and are prevented from moving, the person operates the carrier cart to lift the front wheels. This operation makes it possible for the front wheels to overcome the step.

[0050] In contrast, with a self-propelled carry cart, there is no need for manual operation such as lifting the front wheel as described above. In this regard, in the first embodiment, the front wheels 31 are driven by a motor to provide the cart body 20 with a propulsive force for traveling. The above-mentioned configuration (1-1) is adopted for the carry cart CC in which the front wheels 31 are driven. That is, the carry cart CC is provided with a support portion 41, a link body 51, and an elastic body 63, and the rotation axis AL1 is positioned lower than the central axis AL2.

[0051] Therefore, although the carry cart CC is self-propelled without being operated by a human, the front wheels 31 can be made to overcome the step 12. Therefore, the above configuration (1-1) is particularly useful for the carry cart CC of the first embodiment, which does not have any means for making the carry cart CC overcome the step 12 other than by making the carry cart CC overcome the step 12 using the driving force of the front wheels 31.

[0052] (1-3) In the first embodiment, as shown in Fig. 1, the front wheel 31 is supported on the support body 42 via a link body 51 and a pair of front support plates 43. In addition, each of the rear wheels 33 is supported on the support body 42 via a pair of rear wheel support parts 45. Therefore, the structures for supporting the front wheel 31 and both rear wheels 33 can be concentrated and arranged around the support parts 41.

[0053] Second embodiment Next, a second embodiment of the carry cart will be described with reference to FIG. The second embodiment differs from the first embodiment in that the elastic portion is formed of an elastic body 64 made of a rubber bush. The elastic body 64 is bowl-shaped with an open rear surface and a bottom at the front end. The outer surface of the bottom is formed in a semi-spherical shape.

[0054] The elastic body 64 is disposed above the rotation axis AL1 of the support shaft 44, and between the link body 51 and the support main body 42. The elastic body 64 is attached at its rear end to the support main body 42 from the front. The hemispherical outer surface of the bottom of the elastic body 64 contacts the rear surface of the boundary portion 54 of the link body 51 at a location higher than the support shaft 44 (rotation axis AL1), and applies a biasing force to the location.

[0055] The configuration other than the above is the same as that of the first embodiment, so the same elements as those described in the first embodiment are denoted by the same reference numerals, and duplicated explanations will be omitted. Therefore, in the second embodiment, although an elastic body 64 different from the elastic body 63 in the first embodiment is used as the elastic portion, the same effects as those of (1-1) to (1-3) above can be obtained.

[0056] In addition, the second embodiment provides the following effects. (2-1) In the second embodiment, in which a rubber bush is used as the elastic body 64, unlike the first embodiment, the spring bearing 61 for receiving the elastic body 63 is not required. Therefore, the structure of the elastic part and therefore the carry cart CC can be simplified.

[0057] (2-2) In the second embodiment, the outer surface of the bottom of the elastic body 64 is formed into a hemispherical shape. Therefore, even if the link body 51 rotates about the rotation axis AL1 and the direction of the load input to the elastic body 64 changes, the load is likely to act on the elastic body 64. The elastic body 64 is likely to undergo compressive elastic deformation regardless of the change in the direction of the input load. It is possible to suppress a large change in the biasing force of the elastic body 64 due to a change in the direction of the input load.

[0058] Third embodiment Next, a third embodiment of the carry cart will be described with reference to FIGS.

[0059] The third embodiment is different from the first embodiment in that an elastic portion 71 made of a leaf spring is used as the elastic portion, and a link portion 75 is used as the link portion. A pair of elastic parts 71 (only one is shown in FIG. 11) are used. The elastic parts 71 are arranged at positions spaced apart from each other in the left-right direction. Each elastic part 71 has a rear plate part 72, a front plate part 73 and a connecting plate part 74, which have the same dimensions in the left-right direction, i.e., the same width. Such an elastic part 71 can be formed, for example, by bending a strip-shaped spring steel material.

[0060] The rear plate portion 72 of each elastic portion 71 extends in the vertical direction and is attached from the front to the support body portion 42. The front plate portion 73 of each elastic portion 71 extends in the vertical direction in front of the rear plate portion 72. The connecting plate portion 74 of each elastic portion 71 connects the lower end of the rear plate portion 72 to the lower end of the front plate portion 73. The connecting plate portion 74 of each elastic portion 71 is curved in an arc shape so as to bulge downwardly, centered on the rotation axis AL1 set between the rear plate portion 72 and the front plate portion 73.

[0061] On the other hand, a pair of link portions 75 (only one is shown in FIG. 11) are used. Both link portions 75 are plate-shaped and are disposed on both sides of the front wheel 31 in the left-right direction, in front of the elastic portion 71. Each link portion 75 includes a front link plate portion 76 and a rear link plate portion 77 disposed adjacent to the rear side of the front link plate portion 76.

[0062] When the front wheel 31 and the rear wheel 33 (only the front wheel 31 is shown in FIG. 11 ) are in contact with a horizontal surface, for example, the general road surface 11, the rear link plate portion 77 of each link portion 75 extends in the front-rear direction. The rear link plate portion 77 may be parallel to the horizontal surface or may be inclined. The front link plate portion 76 of each link portion 75 is inclined with respect to the horizontal surface so as to be lower toward the front. The rear link plate portion 77 of each link portion 75 is connected at its front end to the rear end of the front link plate portion 76. In other words, the front link plate portion 76 and the rear link plate portion 77 of each link portion 75 are connected in a bent state. The front end of each front link plate portion 76 constitutes the front end of the link portion 75, and the rear end of each rear link plate portion 77 constitutes the rear end of the link portion 75.

[0063] The front link plate 76 of each link 75 has a notch 78 extending obliquely upward and rearward from the front lower end of the front link plate 76. The portions of the axle 32 that protrude outward on both sides in the left-right direction from the front wheel 31 are inserted into and supported by the notch 78 of each link 75.

[0064] The rotation axis AL1 is located at a position lower than the central axis AL2 of the axle 32. Each link portion 75 is connected to one of the left-right side edges of the front plate portion 73 of the elastic portion 71 above the rotation axis AL1, for example, at an upper end portion of the front plate portion 73. In the third embodiment, each link portion 75 is formed integrally with the elastic portion 71.

[0065] Each elastic portion 71, above the rotation axis AL1, applies a biasing force to the link portion 75. Each link portion 75 rotates in the vertical direction about the rotation axis AL1 as a result of the elastic deformation of each elastic portion 71.

[0066] The configuration other than the above is the same as that of the first embodiment, so the same elements as those described in the first embodiment are denoted by the same reference numerals, and duplicated explanations will be omitted. Next, the operation of the third embodiment will be described. In the third embodiment, as shown in FIG. 11, the front wheel 31 rolling forward comes into contact with the rear corner 14 of the step 12 from behind. As in the first embodiment, a reaction force RF1 acting diagonally upward and rearward from the corner 14 acts on the front wheel 31. This reaction force RF1 is transmitted to the elastic part 71 behind each link part 75. Of each elastic part 71, mainly the part in front of the rotation axis AL1 elastically deforms rearward, and each front plate part 73 inclines with respect to the vertical plane so that the upper part is positioned rearward. As each front plate part 73 inclines, each link part 75 tries to rotate upward about the rotation axis AL1, and an upward force F1 acts on the front wheel 31.

[0067] In addition, when the front wheel 31 rotating forward and downward comes into contact with the corner 14 of the step 12, a reaction force RF2 acting diagonally forward and upward acts on the front wheel 31 from the step 12, as in Figure 3 above, and an upward component force Fa of this reaction force RF2 acts on the front wheel 31.

[0068] The force F1 and the component force Fa, both of which are directed upward, lift up the front wheel 31. The engagement allowance Δh becomes smaller, and the force required for the front wheel 31 to get over the step 12 becomes smaller. When the front wheel 31 runs over the step 12, that is, when it passes the corner 14, the reaction force RF1 acting diagonally upward and rearward no longer acts on the front wheel 31. The elastic restoring force of each elastic portion 71 causes the front plate portion 73 to assume a position extending in the vertical direction. Each link portion 75 rotates downward about the rotation axis AL1, and the front wheel 31 returns to the state it was in before it ran over the step 12.

[0069] Therefore, in the third embodiment, an elastic portion 71 different from the elastic body 63 of the first embodiment is used as the elastic portion, and a link portion 75 similar to the link body 51 of the first embodiment is used as the link portion, but the same effects as those of (1-1) to (1-3) above can be obtained.

[0070] In addition, the third embodiment provides the following effects. (3-1) The link portion 75 and the elastic portion 71 are integrally formed. Therefore, the number of parts is smaller than when the link portion 75 and the elastic portion 71 are formed from separate members. Also, the support shaft 44 used in the first embodiment is not necessary. This also reduces the number of parts. Furthermore, the structure can be simplified.

[0071] (3-2) In the third embodiment, when a load is applied from the front to each elastic portion 71 via each link portion 75, each front plate portion 73 changes its inclination with respect to the vertical plane, centered on the rotation axis AL1. Even if the direction of the load input from each link portion 75 to each elastic portion 71 changes, the load is likely to act on each elastic portion 71. Each elastic portion 71 is likely to elastically deform, regardless of the change in the direction of the input load. As in (2-2) above, it is possible to prevent the biasing force of the elastic portion 71 from changing significantly due to a change in the direction of the input load.

[0072] The above embodiment can also be implemented as modified examples as follows: The above embodiment and the following modified examples can be implemented in combination with each other within a range that does not cause technical contradiction.

[0073] <Matters Concerning the Cart Body 20> The cart body 20 may have the structure shown in FIGS. 13 and 14, for example. The cart body 20 includes a vertically extending main shaft pipe 21 (see FIG. 14) as a skeletal member. Although not shown, a handle that is to be gripped by a user of the carry cart CC may be provided above the main shaft pipe 21.

[0074] The cart body 20 is provided with a carrier 22 in front of the main shaft pipe 21 and a base 26 in rear of the main shaft pipe 21 . The loading platform 22 includes a plate-shaped loading platform plate 23 (see FIG. 13) and a loading platform frame 25 disposed around the loading platform plate 23.

[0075] The platform plate 23 includes a bottom plate portion 23a on which an object to be transported is placed, and a back plate portion 23b rising from the rear end portion of the bottom plate portion 23a. The bottom plate portion 23a is attached to the outer periphery of the spindle pipe 21 via an attachment member 24.

[0076] The loading platform frame 25 includes a bottom frame portion 25a arranged to surround the bottom plate portion 23a, and a back frame portion 25b arranged to surround the back plate portion 23b. The bottom frame portion 25a is attached to the bottom plate portion 23a, and the back frame portion 25b is attached to the back plate portion 23b. The back frame portion 25b is fixed to the rear end portion of the bottom frame portion 25a at its vertical middle portion. The lower end portion of the back frame portion 25b is attached to the front support plate 43.

[0077] The base 26 includes a mounting base 27 (see FIG. 14), a receiving frame 28, and a mounting plate 29. The mounting base 27 is attached to the outer periphery of the spindle pipe 21 at a position lower than the mounting position of the mounting member 24. The receiving frame 28 is fixed to the mounting base 27, and the mounting plate 29 is fixed onto the receiving frame 28. The mounting plate 29 is a portion on which a transported object such as luggage is placed, and is flat. The mounting plate 29 is located at a position lower than the bottom plate 23a of the loading platform plate 23. For example, a storage case 30 is attached to the mounting plate 29, and the transported object may be stored in the storage case 30.

[0078] In this way, the cart body 20 has locations (loading platform 22 and pedestal 26) on which transported objects are placed, respectively, in front of and behind the spindle pipe 21. In addition, the vertical position of the location (loading platform 22) on which the transported objects are placed at the front side of the spindle pipe 21 and the vertical position of the location (pedestal 26) on which the transported objects are placed at the rear side of the spindle pipe 21 are mutually different.

[0079] The support part 41 described in the first embodiment and the like is located below the cart body 20 in the carry cart CC shown in Figs. 13 and 14. The support part 41 includes a support main body part 42 constituting its framework, and a pair of front support plates 43. The support main body part 42 is fixed to the lower end of the main shaft pipe 21. Unlike the first embodiment and the like, the support part 41 does not include a rear wheel support part 45 for each rear wheel 33. The rear wheel support part 45 for each rear wheel 33 is attached to a part of the base 26, for example, the receiving frame part 28 and the mounting plate part 29, instead of the support main body part 42.

[0080] In the carry cart CC shown in Figs. 13 and 14, an elastic body 64 (see Fig. 14) made of a rubber bush is used as the elastic portion, similarly to the second embodiment (see Fig. 10).

[0081] As described above, even in the carry cart CC having the cart main body 20 shown in Figures 13 and 14, since it is equipped with a support part 41, a link body 51 and an elastic body 64, and the rotation axis AL1 is lower than the central axis AL2, the same effects as those of the first embodiment, etc. can be obtained.

[0082] The vertical position of the cart body 20 may be changed, provided that the cart body 20 is positioned above the points where the wheels (front wheels 31, rear wheels 33) contact the road surface 10. For example, the bottom surface of the cart body 20 may be located higher than the bottom ends of the wheels (front wheels 31, rear wheels 33) and lower than the top ends.

[0083] <Wheel-related matters> The number of front wheels 31 may be changed to more than one. Also, the number of rear wheels 33 may be changed to three or more. Also, when the number of front wheels 31 is changed to more than one, the number of rear wheels 33 may be changed to one.

[0084] The front wheel 31 may be rotated by a motor provided outside the front wheel 31. The front wheels 31 may be driven by a power source other than a motor. The rear wheels 33 may be drive wheels that are rotated and driven by a power source, and the front wheels 31 may be driven wheels. Also, in addition to the front wheels 31, the rear wheels 33 may be drive wheels that are rotated and driven by a power source.

[0085] The front wheels 31 and the rear wheels 33 may have different wheel diameters. Although not described in the above embodiments, at least one of the front wheels 31 and the rear wheels 33 is configured as a swivel caster. When some of the front wheels 31 and the rear wheels 33 are configured as swivel casters, the remaining are configured as fixed casters.

[0086] The swivel casters turn freely in response to changes in the direction of the Carry Cart CC, allowing the Carry Cart CC to change direction and move smoothly. The swivel casters offer greater freedom of operation than the fixed casters. In contrast, the fixed casters cannot turn, so they are easier to operate when the Carry Cart CC is moving in a straight line.

[0087] It is preferable to determine which of the front wheels 31 and the rear wheels 33 are swivel casters and which are fixed casters depending on the environment in which the carry cart CC is used. When the front wheels 31 are swivel casters and the rear wheels 33 are fixed casters, the carry cart CC moves stably. When the front wheels 31 are fixed casters and the rear wheels 33 are swivel casters, the carry cart CC can turn with little force. When all the wheels are swivel casters, the carry cart CC can be turned with small turning radius, and is suitable for narrow spaces and places where there are many changes of direction.

[0088] 13 and 14 show an example in which the front wheels 31 are configured as fixed casters, and the rear wheels 33 are configured as swivel casters. At least one of the front wheels 31 and the rear wheels 33 may be configured as a caster with a stopper (with a brake).

[0089] <Matters regarding support part 41> The support body portion 42 may be any portion that constitutes at least a skeletal portion of the support portion 41. Therefore, the entire support portion 41 may be constituted by the support body portion 42.

[0090] <Matters regarding links> The link body 51 and the link portion 75 in each of the above-described embodiments do not necessarily have to be bent. The link body 51 and the link portion 75 may be, for example, in the shape of a triangular plate.

[0091] At least one of the link body 51 and the link portion 75 may support the axle 32 of the front wheel 31 at a location rearward of its front end portion. The link body 51 may be supported by the front support plate 43 via the support shaft 44 at a location forward of its rear end portion. The link portion 75 may be connected to the front plate portion 73 at a location forward of its rear end portion.

[0092] The front link portion 52 and the rear link portion 53 of the link body 51 may be formed of separate members and connected to each other. The same applies to the link portion 75, and the front link plate portion 76 and the rear link plate portion 77 may be formed of separate members and connected to each other.

[0093] <Matters regarding elastic parts> The elastic portion may be made of an elastic body or an elastic portion different from those used in the first to third embodiments. For example, the elastic portion or elastic body may be made of a type of spring different from a coil spring and a leaf spring.

[0094] In the third embodiment, a pair of link portions 75 may be connected to a common elastic portion 71. In this case, the link portions 75 extend forward from both side edges of the common elastic portion 71 in the left-right direction of the front plate portion 73.

[0095] The front parts of each pair of links 75, each of which includes a front link plate portion 76, sandwich the front wheel 31 from both left and right sides. The parts of the axle 32 that protrude outward on both left and right sides from the front wheel 31 are inserted into and supported by the cutout portions 78 of each link portion 75.

[0096] In the third embodiment, the link portion 75 and the elastic portion 71 may be formed of separate members. In this case, however, a structure for connecting the link portion 75 to the elastic portion 71 is required.

[0097] <Matters related to the structure for supporting the front wheel 31 on the support portion 41> In the first embodiment, a cutout portion similar to that in the third embodiment may be formed in the front link portion 52 of the link body 51. The portions of the axle 32 that protrude outward on both sides in the left-right direction from the front wheel 31 may be inserted into and supported by the cutout portion.

[0098] Conversely, in the third embodiment, bearing holes similar to those in the first embodiment may be formed in the front link plate portion 76 of the link portion 75. The portions of the axle 32 that protrude outward on both sides in the left-right direction from the front wheel 31 may be inserted into and supported by the bearing holes.

[0099] <Other> The carry cart of the present invention may be applied to a non-self-propelled carry cart. According to this modification, when the front wheel 31 comes into contact with the step 12, the front wheel 31 can be made to climb over the step 12 without manual operation such as lifting the front wheel 31. Even if the front wheel 31 comes into contact with the step 12, the user of the carry cart can easily overcome the step 12, making the carry cart easier to use.

[0100] The cart body 20 may be provided with a seat for a person to sit on and a shopping basket. The cart body 20 may have a structure for removably mounting a shopping basket. The cart body 20 may also have a location for hanging a carrier bag, a purse, or other bag.

[0101] The carry cart may be equipped with a brake mechanism to stop the cart from moving. According to this modification, a braking force can be applied to at least one of the front wheels 31 and the rear wheels 33 while the cart is moving, making the rotation speed variable. Also, the rotation can be stopped to stop the cart from moving.

[0102] The carrier cart may also include a brake for keeping the carrier cart stationary when parked, or, in the case of a carrier cart with a seat, may include a brake for keeping the carrier cart stationary when a person sits on the seat. [Explanation of symbols]

[0103] 10…road surface 20…Cart body 31…Front wheel 32,34…Axle 33…Rear wheel 41...Support part 42...Support body part 44…Spindle 51...Link body (link part) 63, 64...Elastic body (elastic portion) 71...Elastic part 72...Rear plate part 73…Front plate part 74...Connection plate part 75…Link section AL1: Rotation axis AL2…center axis line CC: Carry Cart

Claims

1. A carry cart comprising wheels that rotate about axles to roll on a road surface, and a cart body that is disposed above the contact points of the wheels with the road surface and on which a transported object is placed, the wheels including front wheels and rear wheels that are disposed rearward of the front wheels in a traveling direction, the carry cart running by the rolling of the wheels, a support part provided between the front wheels and the rear wheels in the traveling direction, the support part having at least a skeletal portion formed by a support main body part; a link portion that supports the axle of the front wheel and rotates in a vertical direction about a rotation axis set at a position rearward of the axle of the front wheel and forward of the support body portion; an elastic portion that is located between the link portion and the support body portion and above the rotation axis and that applies a biasing force to the link portion; wherein when both the front wheels and the rear wheels are in contact with a horizontal surface, the pivot axis is located at a position lower than the central axis of the axle of the front wheels.

2. the link portion is configured by a link body supported by a support shaft having the rotation axis so as to be rotatable in the vertical direction relative to the support portion, 2. The carry cart according to claim 1, wherein the elastic portion is configured by an elastic body disposed between the link body and the support body portion above the support shaft.

3. the elastic portion includes a rear plate portion extending in a vertical direction and attached to the support body portion, a front plate portion extending in the vertical direction in front of the rear plate portion, and a connecting plate portion connecting lower ends of the rear plate portion and the front plate portion to each other, The connecting plate portion is curved in an arc shape so as to bulge downward about the rotation axis line set between the rear plate portion and the front plate portion, 2. The carry cart according to claim 1, wherein the link portion is connected to the front plate portion, and the link portion is adapted to rotate vertically about the rotation axis as a center by elastic deformation of the elastic portion.

4. 4. The carry cart according to claim 3, wherein the link portion is plate-shaped and is formed integrally with the elastic portion.

5. The carry cart according to any one of claims 1 to 4, wherein the front wheels are drive wheels that are rotated by a power source and provide the cart body with propulsive force for traveling.

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