JP7809263B2 - trolley - Google Patents

Description

This invention relates to a trolley, and in particular to a trolley suitable for use when transporting pipe materials.

A known transport cart for carrying and transporting materials or cargo is one that has a horizontal load support plate formed as a single plate of uniform thickness on which the load is placed, and four swivel wheels that are attached to the underside of the load support plate and rotate eccentrically (see Patent Document 1).

Japanese Patent Application Publication No. 7-291132

However, with conventional carriages such as those described in Patent Document 1, when transporting pipe material with a circular cross section perpendicular to the axial direction, there is a problem in that the pipe material rolls on the horizontal load support plate and then rolls off the plate.

The object of this invention is to provide a cart that can transport materials, luggage, etc. while stably holding them so that they do not roll off the loading surface.

To solve the above problem, the cart of this invention is characterized by having a movable support portion provided at the end of the loading surface that moves between a position where it protrudes above the loading surface and a position where it does not protrude above the loading surface.

The cart according to the present invention may be configured so that the cargo receiving portion, which constitutes at least a portion of the loading surface, has top ends at both ends, a bottom in the middle, and slopes that slope downward from each of the top ends to the bottom.

The bogie of this invention may be configured so that the movable support portion acts as a support for an object moving in a direction perpendicular to the downward slope (i.e., the direction from each top end to the bottom).

The cart according to the present invention may be fitted with hooks for engaging load fastening devices that fasten and secure materials placed on the loading surface to prevent them from collapsing.

The dolly of this invention may be configured so that the ends of cargo fasteners engage with the hooks via hooking devices, and the cargo fasteners are passed through the hooks of each of the stacked dollies, thereby binding and securing the dollies together in a stacked state.

The bogie of this invention may be fitted with a pipe insertion section into which a pipe whose axis runs vertically can be inserted and removed freely.

The bogie according to the present invention may be configured such that the dimensions of each part of the bogie are adjusted to satisfy the following mathematical formula 1.
(Math. 1) P < w×tanθ
Here,
P: Horizontal load [kg] acting at the height of the center of gravity in a cross-sectional view along the downward slope of the pipe material placed on the load receiving section so that the axial direction is along a direction perpendicular to the downward slope.
w: Weight of pipe material [kg]
θ: Angle connecting the center of gravity of the pipe material in a cross-sectional view along the downward gradient direction with the contact point of the wheel with the radial direction along the downward gradient direction with respect to the contact surface of the bogie

The cart of this invention has a movable support portion that moves between a position where it protrudes above the loading surface on which materials, luggage, etc. are placed and a position where it does not protrude above the loading surface.This means that the movable support portion acts as a support (in other words, a stopper) for materials, luggage, etc. placed on the loading surface, stably holding the materials, luggage, etc. so that they do not roll off the loading surface while being transported.It also makes it possible to prevent the movable support portion from becoming an obstacle when loading or unloading materials, luggage, etc. onto or from the loading surface.

With the cart of this invention, if the cargo receiving section has top edges at both ends, a bottom in the middle, and slopes that slope downward from each of the top edges to the bottom, the recess formed by the bottom of the cargo receiving section and the pair of slopes can support materials, luggage, etc., making it possible to transport materials, luggage, etc. while holding them stably and preventing them from rolling off the cargo receiving section.

With the trolley of this invention, if the movable support members act as supports for objects moving in a direction perpendicular to the downward slope of the receiving section's sloped surface (i.e., the direction from each of the top edges to the bottom), then, for example, when transporting a single large-diameter pipe, the recess formed by the bottom of the receiving section and a pair of sloped surfaces can be used to stably hold and transport the large-diameter pipe so that it does not roll off the receiving section. Furthermore, when transporting multiple small-diameter pipes, the movable support members can be used to stably hold and transport the small-diameter pipes so that they do not roll off the loading surface.

When the dolly of this invention is equipped with hooks, it is possible to fasten and secure materials, luggage, etc. placed on the loading surface to prevent them from falling over.

When hooks are attached to the trolley of this invention, and by using the hooks, multiple trolleys can be easily tied together and secured to one another in a stacked state, allowing for safe and stable transportation.

When the trolley of this invention is equipped with a pipe insertion section, inserting a pipe into the pipe insertion section can prevent materials or luggage placed in the cargo receiving section from rolling off the section, and can also be used as a control rod that can be grasped and functions like a handle when moving the trolley.

With the trolley of this invention, if the dimensions of each part of the trolley are adjusted to satisfy the above formula 1, the trolley can be prevented from tipping over, ensuring safety when transporting pipe materials.

1 is an XY plane view showing the structure of a carriage according to an embodiment of the present invention; FIG. 2 is an XZ plane view of the carriage of FIG. 1. FIG. 2 is a YZ plane view of the carriage of FIG. 1. 2 is a cross-sectional view of the carriage of FIG. 1 taken along the YZ plane along II. 2 is an XZ plane view showing the operation of the movable support portion of the carriage of FIG. 1. 1 is a perspective view showing an embodiment of a bogie according to the present invention. 1. FIG. 4 is an XZ plane view showing another example of the movable support portion of the carriage of FIG. 2 is a YZ plane view showing an example of a state in which the dolly of FIG. 1 is used. FIG. 1. FIG. 4 is an XZ plane view showing another example of the state in which the dolly of FIG. 1 is used. FIG. 2 is a YZ plane view showing the state of use for calculating the rollover resistance performance of the dolly of FIG. 1. FIG. 10 is an XZ view showing an example of stacking multiple carts using the first hook. FIG. 10 is an XY plane view showing the structure of another embodiment of the bogie according to the present invention. FIG. 12 is an XZ plane view of the carriage of FIG. 11. FIG. 12 is a YZ plane view of the carriage of FIG. 11.

The present invention will be described below based on the illustrated embodiments. In the following description, the X-axis, Y-axis, and Z-axis directions are defined along the axes of a three-dimensional Cartesian coordinate system, as shown in the figures. Note that the Z-axis arrow points upward, and the direction opposite to the Z-axis arrow points downward.

Figures 1 to 5 are diagrams showing the structure of a bogie 1 according to an embodiment of the present invention. Figure 6 is a perspective view showing one example of a bogie according to the present invention. Note that although there are differences in the details between the bogie 1 shown in Figures 1 to 5 and the bogie shown in Figure 6, these differences do not relate to the essential parts of the present invention, and the present invention can employ either the structure shown in Figures 1 to 5 or the structure shown in Figure 6.

The cart 1 in this embodiment has a movable support 5 that is located at the edge of the loading surface on which materials, luggage, etc. are placed and moves between a position where it protrudes above the loading surface and a position where it does not protrude above the loading surface. The cargo receiving section 2 that forms part of the loading surface has top ends 21 at both ends, a bottom 22 in the middle, and slopes 23 that slope downward from each of the top ends 21 to the bottom 22. The movable support 5 acts as a support for objects that move in a direction (X-axis direction in the example shown in the figure) perpendicular to the downward slope of the slopes 23 of the cargo receiving section 2 (i.e., the direction from each of the top ends 21 to the bottom 22; in the example shown in the figure, the Y-axis direction).

The trolley 1 in this embodiment mainly comprises a load receiving section 2, a pair of wheel support members 3, a pair of beam members 4, four movable support members 5, and four wheels 6.

The cargo receiving section 2 is used to place materials, luggage, etc., and is rectangular when viewed in the X-Y plane. The cargo receiving section 2 is located at the middle of the wheel receiving members 3 in the X-axis direction, spanning between a pair of wheel receiving members 3 along the Y-axis direction.

The cargo receiving section 2 has a pair of top ends 21, a bottom 22, a pair of slopes 23, and a pair of walls 24.

The top end 21 is provided horizontally along the XY plane at each end of the cargo receiving section 2 in the Y-axis direction when viewed from the XY plane.

The bottom 22 is located horizontally along the X-Y plane in the middle of the receiving section 2 in the Y-axis direction.

The sloped surface portions 23 are provided between each top end 21 and bottom end 22, and are inclined downward from the top end 21 to the bottom end 22 relative to the X-Y plane (i.e., the horizontal plane).

The wall portion 24 extends downward from the end of each top end portion 21 in the Y-axis direction when viewed in the X-Y plane.

The underside of each top end 21 is joined to the upper surface of the wheel receiving member 3, the inner surface of each wall 24 is joined to the side surface of the wheel receiving member 3, and the underside of the bottom 22 is joined to the upper surface of the beam member 4. The top end 21 and each wall 24 are joined to the wheel receiving member 3, and the bottom 22 is joined to the beam member 4, for example, by welding or by fastening with fastening members such as screws.

The material of the cargo receiving section 2 is not limited to a specific type of material, and an appropriate material can be selected based on factors such as strength and weight. The cargo receiving section 2 is formed, for example, from an aluminum alloy.

As shown in Figure 1, when viewed in the X-Y plane, the cargo receiving section 2 is formed symmetrically with respect to a line along the X-axis direction that passes through the center Cy of the distance Lw along the Y-axis direction between the contact points Gw (see Figures 3 and 4) of the wheels 6 on the ground surface G when the radial direction of the wheels 6 is along the X-Z plane.

As shown in Figures 3 and 4, when viewed in the Y-Z plane, the cargo receiving section 2 is formed symmetrically with respect to a line along the Z-axis direction that passes through the center Cy of the distance Lw along the Y-axis direction between the contact points Gw of the wheels 6 on the ground surface G when the radial direction of the wheels 6 is along the X-Z plane.

The wheel support members 3 are positioned between the cargo receiving section 2 and the wheels 6 to support the cargo receiving section 2 from below while attaching the wheels 6. They are configured as a pair, each supporting both ends of the cargo receiving section 2 in the Y-axis direction (specifically, a pair of top ends 21).

The pair of wheel support members 3 are arranged on the underside of the cargo receiving section 2, with their respective longitudinal directions aligned with the X-axis direction, and spaced apart from each other in the Y-axis direction so as to support both end portions of the cargo receiving section 2 in the Y-axis direction (specifically, the pair of top ends 21).

The material of the wheel receiving member 3 is not limited to a specific type of material; an appropriate material can be selected taking into consideration factors such as strength and weight. The wheel receiving member 3 is formed, for example, by die-casting an aluminum alloy. While the wheel receiving member 3 may be formed by combining multiple parts, it is preferable to form it as a single piece, particularly from the perspective of ensuring good strength.

A pair of beam members 4 are arranged on the underside of the wheel receiving member 3. The pair of beam members 4 are provided so that their longitudinal directions run along the Y-axis direction and are spaced apart from each other in the X-axis direction, spanning the pair of wheel receiving members 3 along the Y-axis direction. The beam members 4 and wheel receiving members 3 are joined, for example, by welding or by being fastened with fastening members such as screws.

With the above-described configuration, the pair of beam members 4 connect the pair of wheel receiving members 3 to each other and support the pair of wheel receiving members 3 and the bottom 22 of the load receiving section 2 from below.

A wheel 6 is attached to each of the pair of wheel receiving members 3 at both ends in the X-axis direction on the underside of the wheel receiving members 3. Specifically, the wheels 6 may be, for example, free wheels that can rotate around the Z-axis (i.e., casters that can rotate horizontally), or fixed wheels that cannot rotate horizontally and whose running direction is fixed in the X-axis direction.

The wheels 6 are attached to the wheel receiving member 3, for example, by fastening them via a top plate 61 (in other words, a mounting base) using fastening members such as screws.

The dimensions of each part that determines the height of the cargo receiving section 2 (e.g., wheel receiving member 3, wheels 6) may be adjusted so that the height of the pipe material placed on the cargo receiving section 2 allows a hand pallet to be used to transport the pipe material.

A first hook 7 is attached to the center of each of the pair of wheel receiving members 3 in the X-axis direction to engage a cargo fastening device (e.g., lashing belt, securing belt) that fastens and secures materials, cargo, etc. placed on the cargo receiving section 2 to prevent them from collapsing. The first hooks 7 are configured as a pair, facing each other in the Y-axis direction.

The first hooks 7 are formed into a U-shape by bending a rod with a circular cross section. The pair of first hooks 7 are attached to the lower end of the wheel receiving member 3 along the X-Y plane, with their U-shaped openings facing each other in the Y-axis direction. The first hooks 7 are attached to the wheel receiving member 3 by welding, for example. A pair of through holes is formed in each of the pair of walls 24 of the cargo receiving section 2 to allow the first hooks 7 to pass through.

In addition, a second hook 8 is attached to each end of the pair of wheel receiving members 3 in the X-axis direction to engage a cargo fastening device (e.g., lashing belt, cargo securing belt) that fastens and secures materials, cargo, etc. placed on the cargo receiving section 2 to prevent the cargo from collapsing.

The second hook 8 is formed into a U-shape by bending a rod with a circular cross section. The second hook 8 is attached to each of the pair of wheel receiving members 3 along the X-Y plane, with the U-shaped openings facing each other in the X-axis direction, and the end of the wheel receiving member 3 in the X-axis direction sandwiched between the openings, to the side of the wheel receiving member 3. The second hook 8 is attached to the wheel receiving member 3 by joining, for example, welding.

The movable protrusions 5 function as supports (or stoppers) to prevent materials, luggage, etc. placed on the cargo receiving section 2 from rolling off. They are provided on each of the pair of wheel receiving members 3, with a pair facing each other in the X-axis direction, at both ends of the wheel receiving member 3 in the X-axis direction. In other words, the direction in which the pair of movable protrusions 5 face each other (i.e., the X-axis direction) is perpendicular to the direction in which the slope 23 of the cargo receiving section 2 slopes downward from the top end 21 to the bottom end 22 (i.e., the Y-axis direction).

The movable support portion 5 has a support portion 51, a movable portion 52, and a support portion 53.

The support portion 51 has a rectangular plate-shaped main body portion 511 and an abutment portion 512 provided at the tip of the main body portion 511.

The movable part 52 is interposed between the support part 51 (specifically, the main body part 511) and the wheel receiving member 3 to rotate the support part 51 relative to the wheel receiving member 3, and has a fixed piece 521, a rotating piece 522, and a rotating shaft 523. A hinge, for example, can be used as the movable part 52.

The fixed piece 521 of the movable part 52 is fixed to the end face of the wheel receiving member 3 in the X-axis direction, for example, by welding. Furthermore, the support part 51 (specifically, the main body part 511) is attached to the rotating piece 522, for example, by welding.

The rotation shaft 523 of the movable part 52 is arranged along the Y-axis direction, and the rotation shaft 523 causes the protrusion support part 51 attached to the rotating piece 522 to rotate along the X-axis direction relative to the wheel receiving member 3 to which the fixed piece 521 is fixed.

The support portion 53 is formed in a roughly triangular plate shape when viewed in the X-Z plane, and is provided vertically along the X-Z plane on one side of the main body portion 511 of the protruding portion 51 (specifically, the surface facing the opposing movable protruding portion 5 in the X-axis direction).

With the above configuration, the protruding portion 51 moves between a position where it protrudes from the upper surface of the end of the wheel receiving member 3 in the X-axis direction (at this time, the support portion 53 abuts against the upper surface of the wheel receiving member 3; see Figure 5(A)), and a position where it retracts to the side of the wheel receiving member 3 in the X-axis direction (at this time, the pivot piece 522 abuts against the second hook 8; see Figure 5(B)). When the protruding portion 51 is in a position where it protrudes from the upper surface of the wheel receiving member 3, it protrudes above the upper surface of the top end 21 of the load receiving section 2, i.e., it protrudes above the loading surface.

When the movable protrusion 5 (particularly the support portion 53) is retracted to the side of the wheel receiving member 3 in the X-axis direction, it is adjusted so that it does not protrude above the top edge 21 of the load receiving section 2 or the upper surface of the wheel receiving member 3 (in other words, the loading surface on which materials, luggage, etc. are placed) (see Figure 5(B)). This prevents the movable protrusion 5 from interfering with loading or unloading materials, luggage, etc. onto or from the load receiving section 2 or wheel receiving member 3.

To prevent the movable support protrusion 5 from rotating unexpectedly, a spring 54 (shown only in Figure 7) may be provided to maintain the support protrusion 51 in a position where it protrudes from the upper surface of the end of the wheel receiving member 3 in the X-axis direction, or in a position where it retracts to the side of the wheel receiving member 3 in the X-axis direction.

Specifically, the spring 54 is disposed between the wheel receiving member 3 and the movable support member 5, with one end engaging with a first spring support shaft 541 fixed to a position near the end of the wheel receiving member 3 in the X-axis direction, and the other end engaging with a second spring support shaft 542 fixed to a position near the tip of the main body 511 of the support member 51 (i.e., near the abutment portion 512).

As shown in Figure 7 (A), when the second spring bearing shaft 542 is positioned above the line connecting the first spring bearing shaft 541 and the rotation shaft 523, the spring 54 exerts a force that pulls the tip of the protruding support portion 51, which rotates around the base end rotation shaft 523 as its axis of rotation, toward the top surface of the wheel receiving member 3. This maintains the protruding support portion 51 in a position that protrudes from the top surface of the end of the wheel receiving member 3 in the X-axis direction.

On the other hand, as shown in Figure 7 (B), when the second spring bearing shaft 542 is positioned below the line connecting the first spring bearing shaft 541 and the rotation shaft 523, the spring 54 exerts a force that pulls the tip of the protruding support portion 51, which rotates around the base end rotation shaft 523 as its axis of rotation, toward the end face of the wheel receiving member 3 in the X-axis direction. This maintains the protruding support portion 51 in a retracted position to the side of the wheel receiving member 3 in the X-axis direction.

The above-described cart 1 is particularly suitable for use when transporting pipe material (however, the objects transported by the cart 1 are not limited to pipe material). Specifically, for example, if the pipe material to be transported is a single large-diameter pipe material 9A, the pipe material 9A is placed on the cargo receiving section 2 so that its axial direction is aligned with the X-axis direction.

In this case, as shown in Figure 8, the pipe material 9A is supported and stably held in the recess formed by the bottom 22 of the cargo receiving section 2 and a pair of sloped sections 23, preventing it from rolling off the cargo receiving section 2.

In this case, when viewed in the Y-Z plane, the cargo receiving section 2 is formed symmetrically with respect to a line along the Z-axis direction that passes through the center Cy of the distance Lw along the Y-axis direction between the contact points Gw of the wheels 6 on the ground surface G when the radial direction of the wheels 6 is along the X-Z plane (see Figures 3 and 4).As a result, the center of gravity of the pipe material 9A when viewed in the Y-Z plane (in other words, the position of the axis of the pipe material 9A along the X-axis direction when viewed in the Y-Z plane) is located on the line along the Z-axis direction.

Depending on the axial dimension of the pipe material 9A, multiple trolleys 1 may be arranged and used, for example, one at each end of the pipe material 9A in the axial direction. Furthermore, the pipe material 9A placed on the cargo receiving section 2 with its axial direction aligned with the X-axis direction is fastened and secured using, for example, a pair of first hooks 7 with lashing belts/tie-down belts (not shown).

Furthermore, if the pipes to be transported are multiple small-diameter pipes 9B, they are placed on the top end 21 of the cargo receiving section 2 so that the axial direction of the pipes 9B is aligned with the Y-axis direction, and are also placed directly on the wheel receiving member 3 (i.e., the top surface of the wheel receiving member 3 also functions as a loading surface for placing materials, luggage, etc.).

In this case, as shown in FIG. 9 , the movable support portion 5 (specifically, the support portion 51 having the abutment portion 512) acts as a support (in other words, a stopper) for the pipe 9B, and the pipe 9B strikes the movable support portion 5 (specifically, the abutment portion 512), receiving and supporting it, preventing it from rolling off the load receiving portion 2 or the wheel receiving member 3. Depending on the axial dimension of the pipe 9B, multiple trolleys 1 may be used, for example, one located near each end of the pipe 9B in the axial direction. Furthermore, the pipe 9B placed on the load receiving portion 2 with its axis aligned along the Y-axis direction is secured by, for example, second hooks 8 (four in total in the illustrated example) and fastened with lashing belts/tie-down belts (not shown).

(Calculation of rollover resistance performance)
The overturning resistance performance of the trolley 1 is calculated when a single large-diameter pipe 9C whose axis is aligned with the X-axis direction is placed on the load receiving section 2 of the trolley 1. Here, we take as an example a case where the distance Lw along the Y-axis direction between the contact points Gw of the wheels 6 with the ground surface G when the radial direction of the wheels 6 is aligned with the X-Z plane (one wheel 6 is in the state indicated by the dashed line in Figure 10) is 460 mm, and the diameter of the pipe 9C is 762 mm.

We will consider the most severe tipping conditions, and here we will consider a state in which the pipe material 9C is placed on the load receiving section 2 so that its axis is aligned with the X-axis direction, and the radial direction of one wheel 6 is aligned with the Y-Z plane, as shown in Figure 10. We will also consider a state in which the cart 1 is moved together with the pipe material 9C from a completely stopped state (i.e., the wheels 6 are completely stopped).

When the radial direction of the wheel 6 is aligned along the Y-Z plane, the distance between the center of gravity Cg of the pipe 9C in the Y-Z plane (in other words, the position of the axis of the pipe 9C along the X-axis direction in the Y-Z plane) and the contact point Gp of the wheel 6 with the ground surface G is shorter than when the radial direction of the wheel 6 is aligned along the X-Z plane (the state of the wheel 6 shown by the dashed line in Figure 10) (because the position of the center of rotation around the Z axis of the wheel 6 in the X-Y plane is misaligned).

In the above state, the angle θ between the center of gravity Cg of the pipe material 9C in the Y-Z plane and the contact point Gp of the wheel 6 with its radial direction aligned with the Y-Z plane, relative to the contact surface G of the bogie 1/wheel 6, is 19.4°.

The equation for calculating the horizontal load P [kg] acting at the height of the center of gravity Cg of the pipe 9C in the Y-Z plane view, which may cause the cart 1 to tip over, is expressed as the following equation 2, where w [kg] is the weight of the pipe 9C. In the example shown in Figure 10, θ = 19.4°.
(Math. 2) tanθ = P/w

Therefore, by adjusting the dimensions of each part of the cart 1 to satisfy the following formula 3, the cart 1 will not tip over.
(Math. 3) P < w×tanθ
Where, P: Horizontal load acting on the height of the center of gravity of the pipe material in the Y-Z plane view
w: Weight of the pipe material
θ: Center of gravity of the pipe material in the Y-Z plane relative to the contact surface of the cart/wheel
The angle between the wheel and the ground contact point when the radial direction is along the Y-Z plane

Regarding the above formula 2, the horizontal load P varies depending on the weight w of the pipe material 9C (specifically, the axial length of the pipe material 9C), so if the horizontal load P is calculated for each axial length of the pipe material 9C/each weight w of the pipe material 9C, the result is as shown in Table 1 below.

The cart 1 will not tip over unless the horizontal load is greater than the horizontal load P calculated above. Referring to the "Design Strength of Handrails" (Ministry of Land, Infrastructure, Transport and Tourism website), the horizontal force exerted by a person pushing an object is 100 to 150 kg/m, and assuming the average shoulder width of a human is 0.6 m, this comes to 60 to 90 kg/person. By applying these values to Table 1 above and performing calculations, Table 2 below is obtained.

From the above, it can be seen that when loading pipe material 9C with a diameter of 762 mm, caution is required when working with two or more people if the length of pipe material 9C is 2 m, and caution is required when working with three or more people if the length of pipe material 9C is 3 m, but in other cases there is little risk of the trolley 1 tipping over.

The dolly 1 according to this embodiment has a movable support portion 5 that is provided at the edge of the loading surface on which materials, luggage, etc. are placed and that moves between a position where it protrudes above the loading surface and a position where it does not protrude above the loading surface. This allows the movable support portion 5 to act as a support (in other words, a stopper) for materials, luggage, etc. placed on the cargo receiving portion 2 or wheel receiving member 3, stably holding and transporting the materials, luggage, etc. so that they do not roll off the cargo receiving portion 2 or wheel receiving member 3 (in other words, the loading surface on which materials, luggage, etc. are placed). Furthermore, the movable support portion 5 can be prevented from interfering with the loading and unloading of materials, luggage, etc. onto or from the cargo receiving portion 2 or wheel receiving member 3.

In the trolley 1 according to the embodiment, the cargo receiving section 2, which forms part of the loading surface on which materials, cargo, etc. are placed, has top ends 21 at both ends, a bottom 22 in the middle, and slopes 23 that slope downward from each of the top ends 21 to the bottom 22. Therefore, the recess formed by the bottom 22 of the cargo receiving section 2 and the pair of slopes 23 can support materials, cargo, etc. (particularly pipe material 9C placed with its axis oriented along the X-axis direction), making it possible to transport materials, cargo, etc. while holding them stably and preventing them from rolling off the cargo receiving section 2.

In the trolley 1 according to this embodiment, the movable support members 5 act as supports for objects moving in a direction (i.e., the X-axis direction) perpendicular to the downward slope of the sloped surfaces 23 of the load receiving section 2 (i.e., the direction from each of the top ends 21 to the bottom 22; i.e., the Y-axis direction). For example, when transporting a single large-diameter pipe 9A, the recess formed by the bottom 22 and pair of sloped surfaces 23 of the load receiving section 2 can be used to stably hold and transport the large-diameter pipe 9A so that it does not roll off the load receiving section 2. Furthermore, when transporting multiple small-diameter pipes 9B, the movable support members 5 can be used to stably hold and transport the small-diameter pipes 9B so that they do not roll off the load receiving section 2 or wheel receiving member 3.

The dolly 1 according to this embodiment is equipped with a first hook 7 and a second hook 8, which allows materials and luggage placed on the loading surface to be fastened and secured to prevent them from falling over.

As shown in Figure 11, the first hook 7 is also used when multiple carts 1 are stacked (note that the movable support member 5 is not shown in Figure 11). Specifically, one end of a cargo tie-down device 11 (e.g., a lashing belt or securing belt) is engaged with the first hook 7 of the lowest cart 1 of the stacked carts 1 via a hooking device 11a. The cargo tie-down device 11 is then passed through the first hook 7 of each of the stacked carts 1, and is then passed to the opposite side in the Y-axis direction on the top surface of the top end 21 of the cargo receiving section 2 of the highest cart 1 of the stacked carts 1. The cargo tie-down device 11 is then passed through the first hook 7 of each of the stacked carts 1 (on the side not visible in Figure 11), and the other end of the cargo tie-down device 11 is engaged with the first hook 7 of the lowest cart 1 of the stacked carts 1 via a hooking device 11a. This makes it easy to bundle and secure multiple carts 1 together in a stacked state, enabling safe and stable transportation.

In the example shown in the figure, the upper plate (in other words, the top plate) of the wheel receiving member 3 has an opening that is wider than the width of the wheel 6 (see, for example, Figure 1). Therefore, when multiple bogies 1 are stacked as shown in Figure 11, each of the four wheels 6 of the upper stacked bogie 1 is positioned within the opening in the upper plate of the wheel receiving member 3 of the lower stacked bogie 1 (the wheels 6 are placed on the top plate 61 of the wheels 6 of the lower stacked bogie 1), thereby restricting the movement of the wheels 6 of the upper stacked bogie 1 in the front-to-back and left-to-right directions, preventing the stacked multiple bogies 1 from collapsing and maintaining a stable stacked state of the multiple bogies 1.

The above describes an embodiment of the present invention, but the specific configuration is not limited to the above embodiment, and design changes that do not deviate from the gist of the present invention are also included in the present invention.

For example, while in the above embodiment the cargo receiving portion 2 is provided only in the middle portion of the wheel receiving member 3 in the X-axis direction, the cargo receiving portion 2 may be provided over the entire wheel receiving member 3 in the X-axis direction. In this case, the protruding portion 51 moves between a position where it protrudes from the upper surface of the end of the top end 21 of the cargo receiving portion 2 in the X-axis direction (at this time, the support portion 53 abuts the upper surface of the top end 21), and a position where it retracts to the side of the top end 21 of the cargo receiving portion 2 and the wheel receiving member 3 in the X-axis direction (at this time, the pivot piece 522 abuts the second hook 8). In other words, the movable protruding portion 5 is provided at the end of the loading surface on which materials, luggage, etc. are placed, and moves between a position where it protrudes above the loading surface (in other words, a protruding position) and a position where it does not protrude above the loading surface.

In the above embodiment, the cargo receiving section 2 has a pair of top edges 21, a bottom 22, a pair of slopes 23, and a pair of walls 24, but the top surface of the cargo receiving section 2 may also be flat. In this case, too, the movable support members 5 allow materials, luggage, etc. to be transported while being stably held so that they do not roll off the cargo receiving section 2 or wheel support members 3.

In the above embodiment, the movable protrusion 5 has a protrusion 51, a movable portion 52, and a support portion 53, and the protrusion 51 rotates due to the rotation axis 523 of the movable portion 52. However, the specific configuration and mechanism of the movable protrusion in this invention is not limited to the movable protrusion 5 in the above embodiment. The movable protrusion may be provided at the end of the loading surface (the load receiving portion 2 or the wheel receiving member 3 in the above embodiment) and may have any configuration or mechanism as long as it has a mechanism that allows it to change between a position/posture/state in which it protrudes above the loading surface and a position/posture/state in which it does not protrude above the loading surface.

As shown in Figures 11 to 14, the cart 1 may have a pipe insertion section 10 into which a pipe (such as a single pipe or a steel pipe; not shown) whose axis runs along the Z-axis (i.e., the vertical direction) can be inserted and removed (note that the movable support section 5 is not shown in Figures 11 to 14). The pipe insertion section 10 has an insertion hole 10a whose axis runs along the Z-axis, and a support plate 10b is installed horizontally along the X-Y plane at the bottom of the insertion hole 10a. This allows a pipe inserted vertically from the upper opening of the insertion hole 10a to be supported by abutting against the support plate 10b. The pipe inserted and supported in the insertion hole 10a prevents materials or luggage placed in the cargo receiving section 2 from rolling off the cargo receiving section 2, and can also be used as a control rod that can be grasped and functions like a handle when moving the cart 1.

In the example shown in Figures 11 to 14, the pipe insertion portion 10 is attached to the end portion in the X-axis direction of the wall portion 24 of the cargo receiving portion 2, but the attachment position of the pipe insertion portion 10 is not limited to the position in the example shown in Figures 11 to 14 and may be shifted in the X-axis direction from the position in the example shown in Figures 11 to 14. The pipe insertion portion 10 may also be attached to the wheel receiving member 3. Also, in the example shown in Figures 11 to 14, one pipe insertion portion 10 (two in total) is attached to one side in the Y-axis direction, but two or more pipe insertion portions 10 (three or more in total) may be attached to one side in the Y-axis direction.

REFERENCE SIGNS LIST 1 Dolly 2 Load receiving section 21 Top end 22 Bottom 23 Slope section 24 Wall section 3 Wheel receiving member 4 Beam member 5 Movable support section 51 Support section 511 Main body section 512 Stop section 52 Movable section 521 Fixed piece 522 Rotating piece 523 Rotating shaft 53 Support section 6 Wheel 61 Top plate (mounting base)
7 First hook 8 Second hook 9A Large diameter pipe 9B Small diameter pipe 9C Pipe 10 Pipe insertion portion 10a Insertion hole portion 10b Receiving plate 11 Load securing device 11a Hook

Claims (7)

a movable protrusion provided at an end of the placement surface and movable between a position protruding above the placement surface and a position not protruding above the placement surface;
The movable protruding portion has a protruding portion that rotates between a position where it protrudes above the placement surface and a position where it does not protrude above the placement surface, and a support portion that is provided on the protruding portion and abuts against the placement surface at the position where it protrudes above the placement surface.
A bogie characterized by: The cargo receiving portion constituting at least a part of the loading surface has top ends at both ends, a bottom at an intermediate portion, and a slope portion that slopes downward from each of the top ends to the bottom.
2. The truck according to claim 1 . The movable support portion acts as a support for an object moving in a direction perpendicular to the downward slope direction.
3. The truck according to claim 2. Hooks are attached to engage with load fasteners that fasten and secure the materials placed on the loading surface to prevent them from collapsing.
4. A bogie according to any one of claims 1 to 3. An end of a cargo fastener is engaged with the hook via a hooking device, and the cargo fastener is passed through each of the hooks of the stacked carts, thereby binding and fixing the carts together in a stacked state.
5. The truck according to claim 4. A pipe insertion section is attached into which a pipe whose axis is aligned vertically can be inserted and removed freely.
6. A truck according to any one of claims 1 to 5. The dimensions of each part of the bogie are adjusted to satisfy the following formula 1:
(Math. 1) P < w×tanθ
Here,
P: Horizontal load [kg] acting at the height of the center of gravity in a cross-sectional view along the downward slope of the pipe material placed on the load receiving section so that the axial direction is along a direction perpendicular to the downward slope.
w: Weight of pipe material [kg]
θ: The bogie described in claim 2 or 3, characterized in that θ is the angle between the center of gravity of the pipe material in a cross-sectional view along the downward slope direction with respect to the contact surface of the bogie and the contact point of the wheel with its radial direction along the downward slope direction.