Dolly

Abstract

To provide a carriage that holds and carries a material and baggage while stabilizing the material and the baggage to prevent the material and the baggage from rolling down.SOLUTION: A baggage receiving part 2 constituting a portion of a placement surface on which a material and baggage are placed has top end portions 21 at both end parts thereof, a bottom portion 22 at an intermediate part, and slope parts 23 sloping down from the top end portions 21 respectively toward the bottom portion 22.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a trolley, and particularly to a trolley suitable for use when transporting pipe materials.

Background Art

[0002] As a trolley for loading and transporting materials and goods, there is known a transport trolley having a horizontal load support plate formed as a single plate of uniform thickness and having a load placed thereon, and four swivel wheels attached to the lower surface of the load support plate and rotating eccentrically (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in a conventional trolley such as Patent Document 1, when transporting a pipe material whose cross-section perpendicular to the axial direction is circular, there is a problem that the pipe material rolls on the horizontal load support plate and rolls off the load support plate.

[0005] Therefore, an object of the present invention is to provide a trolley capable of transporting while stably holding materials and goods so as not to roll off from the placement surface.

Means for Solving the Problems

[0006] In order to solve the above problems, a trolley according to the present invention is characterized in that a load receiving portion constituting at least a part of the placement surface has top ends of both end portions, a bottom portion of an intermediate portion, and normal surfaces with a downward gradient extending from each of the top ends to the bottom portion.

[0007] The trolley according to this invention may be equipped with hooks for engaging with load securing devices to fasten and fix materials placed on the aforementioned surface so as not to shift or collapse.

[0008] The trolley according to this invention may be configured such that the end of the cargo securing device is engaged with the hook via a hooking device, and the cargo securing device is passed through each of the hooks of each of the multiple trolleys stacked on top of each other, thereby binding and securing them together in a stacked state.

[0009] The trolley according to this invention may be equipped with a pipe insertion section into which a pipe whose axis direction is aligned with the vertical direction can be inserted and removed.

[0010] The trolley according to this invention may be configured such that the dimensions of each part of the trolley satisfy the following formula 1. (Math. 1) P < w×tanθ Here, P: Horizontal load [kg] acting on the height of the center of gravity in a cross-sectional view along the direction of the downward slope of the pipe material placed on the load-receiving section so that its axial direction is perpendicular to the direction of the downward slope. w: Weight of pipe material [kg] θ: An angle connecting the center of gravity in a cross-sectional view of the pipe material along the direction of the downward slope, with respect to the contact surface of the trolley, and the contact point of the wheel when its radial direction is along the direction of the downward slope. [Effects of the Invention]

[0011] According to the trolley of this invention, the load-receiving section has top ends at both ends, a bottom in the middle, and slopes that slope downward from each of the top ends towards the bottom. As a result, the recess formed by the bottom of the load-receiving section and the pair of slopes can support materials and luggage, making it possible to transport materials and luggage while holding them stably and preventing them from rolling off the load-receiving section.

[0012] According to this invention, if hooks are attached to the trolley, it becomes possible to tighten and secure materials, luggage, etc. placed on the mounting surface to prevent them from collapsing.

[0013] According to the trolley of this invention, if hooks are attached, and by using the hooks, multiple trolleys can be easily bound together and secured to each other in a stacked state, making it possible to transport them safely in a stable state.

[0014] According to the trolley of this invention, if a pipe insertion part is attached, inserting a pipe into the pipe insertion part prevents materials or luggage placed on the loading area from rolling off the loading area, and the pipe can be used as an operating rod that can be gripped and function like a handle when moving the trolley.

[0015] According to 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, thereby ensuring safety when transporting pipe materials. [Brief explanation of the drawing]

[0016] [Figure 1] This is an XY view showing the structure of a trolley according to an embodiment of the present invention. [Figure 2] Figure 1 is an XZ view of the trolley. [Figure 3] Figure 1 is a YZ view of the trolley. [Figure 4] This is a cross-sectional view II along the YZ plane of the trolley in Figure 1. [Figure 5] Figure 1 is an XZ view showing the operation of the movable projection of the trolley. [Figure 6] This is a perspective view showing an embodiment of the trolley according to this invention. [Figure 7] This is an XZ view showing another example of the movable projection of the trolley in Figure 1. [Figure 8]It is a Y-Z plane view showing an example of the usage state of the carriage in FIG. 1. [Figure 9] It is an X-Z plane view showing another example of the usage state of the carriage in FIG. 1. [Figure 10] It is a Y-Z plane view showing the usage state for calculating the tipping resistance performance of the carriage in FIG. 1. [Figure 11] It is an X-Z plane view showing an example when stacking multiple carriages using the first hook. [Figure 12] It is an X-Y plane view showing the structure of another embodiment of the carriage according to this invention. [Figure 13] It is an X-Z plane view of the carriage in FIG. 11. [Figure 14] It is a Y-Z plane view of the carriage in FIG. 11.

Embodiments for Carrying Out the Invention

[0017] Hereinafter, this invention will be described based on the illustrated embodiments. In the following description, as shown in each figure, directions in the X-axis direction, Y-axis direction, and Z-axis direction are defined along each axis of the three-dimensional orthogonal coordinate system. Note that the direction of the arrow of the Z-axis is upward, and the direction opposite to the direction of the arrow of the Z-axis is downward.

[0018] FIGS. 1 to 5 are views showing the structure of the carriage 1 according to the embodiments of this invention. FIG. 6 is a perspective view showing one example of the carriage according to this invention. Although the carriage 1 shown in FIGS. 1 to 5 and the carriage shown in FIG. 6 are different in details, the differences are not related to the essential parts of this invention, and in this invention, either the structure shown in FIGS. 1 to 5 or the structure shown in FIG. 6 can be adopted.

[0019] The trolley 1 according to this embodiment has a load-receiving section 2 that constitutes a part of the loading surface on which materials and luggage are placed, and has top ends 21 at both ends, a bottom part 22 in the middle, and sloped sections 23 that slope downward from each of the top ends 21 toward the bottom part 22. It also has a movable projection 5 provided at the end of the aforementioned loading surface that moves between a position that protrudes above the aforementioned loading surface and a position that does not protrude above the aforementioned loading surface, and the movable projection 5 acts as a support for objects moving in a direction perpendicular to the direction of the downward slope of the sloped section 23 of the load-receiving section 2 (i.e., the direction toward the bottom part 22 from each of the top ends 21; in the example shown in the figure, the Y-axis direction) (in the example shown in the figure, the X-axis direction).

[0020] The trolley 1 according to this embodiment mainly comprises a load-receiving section 2, a pair of wheel-receiving members 3, a pair of beam members 4, four movable projections 5, and four wheels 6.

[0021] The load-receiving section 2 is for placing materials and cargo, and is formed in a rectangular shape in the XY plane view. The load-receiving section 2 is provided in the middle portion of the wheel support member 3 in the X-axis direction, and is spanned between a pair of wheel support members 3 along the Y-axis direction.

[0022] The load-receiving section 2 has a pair of top sections 21, a bottom section 22, a pair of slope sections 23, and a pair of wall sections 24.

[0023] The top portion 21 is provided horizontally along the XY plane at each of the ends of the load-receiving portion 2 in the Y-axis direction when viewed in the XY plane.

[0024] The bottom portion 22 is provided horizontally along the XY plane in the middle portion of the load-receiving portion 2 in the Y-axis direction.

[0025] The slope portion 23 is provided between each top portion 21 and bottom portion 22, with a downward slope from the top portion 21 to the bottom portion 22 and inclined with respect to the XY plane (i.e., the horizontal plane).

[0026] The wall portion 24 is provided extending downward from the end of each top end 21 in the Y-axis direction in the XY plane view.

[0027] The lower surface of each top section 21 is joined to the upper surface of the wheel support member 3, the inner surface of each wall section 24 is joined to the side surface of the wheel support member 3, and the lower surface of the bottom section 22 is joined to the upper surface of the beam member 4. Each top section 21 and each wall section 24 are joined to the wheel support member 3, and the bottom section 22 is joined to the beam member 4, for example, by welding or by fastening with screws or other fastening members.

[0028] The material of the load-receiving section 2 is not limited to a specific type of material; rather, an appropriate material is selected as needed, taking into consideration factors such as strength and weight. For example, the load-receiving section 2 is formed from an aluminum alloy.

[0029] As shown in Figure 1, the load-receiving section 2 is formed symmetrically with respect to a straight line along the X-axis that passes through the center Cy of the distance Lw along the Y-axis between the contact points Gw of the wheel 6 with the ground surface G (see Figures 3 and 4) when the radial direction of the wheel 6 is aligned with the XZ-axis in an XY-plane view.

[0030] The load-receiving section 2 is also formed symmetrically with respect to a straight 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 with the ground surface G, when the radial direction of the wheels 6 is aligned with the XZ-plane, as shown in Figures 3 and 4.

[0031] The wheel support members 3 are interposed between the load-receiving section 2 and the wheel 6 to support the load-receiving section 2 from below while mounting the wheel 6. They are configured as a pair, each supporting both ends of the load-receiving section 2 in the Y-axis direction (specifically, a pair of top ends 21).

[0032] The pair of wheel support members 3 are arranged on the lower surface side of the load-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 each of the ends of the load-receiving section 2 in the Y-axis direction (specifically, the pair of top ends 21).

[0033] The material of the wheel support member 3 is not limited to a specific type of material; an appropriate material is selected as appropriate, taking into consideration factors such as strength and weight. The wheel support member 3 is formed, for example, by die-casting an aluminum alloy. Although the wheel support member 3 may be formed by combining multiple parts, it is preferable that it be integrally molded, especially from the viewpoint of ensuring good strength.

[0034] A pair of beam members 4 are arranged on the lower side of the wheel support member 3. The pair of beam members 4 have their respective longitudinal directions aligned with the Y-axis direction and are spaced apart from each other in the X-axis direction, and are provided spanning between the pair of wheel support members 3 along the Y-axis direction. The beam members 4 and the wheel support members 3 are joined, for example, by welding or by fastening with screws or other fasteners.

[0035] The pair of beam members 4, in the configuration described above, connect the pair of wheel support members 3 to each other and support the pair of wheel support members 3 and the bottom 22 of the load-bearing section 2 from below.

[0036] Wheels 6 are attached to each of the two ends of the lower surface of each of the pair of wheel support members 3 in the X-axis direction. Specifically, the wheels 6 may be, for example, swivel wheels that can rotate around the Z-axis (i.e., casters that can rotate horizontally) or fixed wheels that cannot rotate horizontally and whose direction of travel is fixed in the X-axis direction.

[0037] The wheel 6 is attached to the wheel support member 3 by fastening it with screws or other fastening members, for example, via the top plate 61 (or mounting base).

[0038] The dimensions of each part that determines the height of the loading section 2 (for example, the wheel support member 3 and the wheel 6) may be adjusted so that the pipe material placed on the loading section 2 is at a height that allows a hand pallet for transporting the pipe material to be used.

[0039] A first hook 7 is attached to the center of each of the pair of wheel support members 3 in the X-axis direction for engaging with a cargo securing device (e.g., a lashing belt, cargo securing strap) to fasten and secure materials and cargo placed on the load support section 2 to prevent them from shifting. The first hooks 7 are configured as a pair, facing each other in the Y-axis direction.

[0040] The first hook 7 is formed into a U-shape by bending a rod with a circular cross-section. A pair of first hooks 7 are attached to the lower end of the wheel support member 3 with their U-shaped openings facing each other in the Y-axis direction, along the XY plane. The first hooks 7 are attached to the wheel support member 3 by joining them, for example, by welding. In order to allow the first hooks 7 to pass through, a pair of through holes are formed in each of the pair of wall portions 24 of the load-receiving portion 2.

[0041] Furthermore, a second hook 8 is attached to each of the two wheel support members 3 in the X-axis direction for engaging with a cargo securing device (e.g., a lashing belt, cargo securing strap) to fasten and secure materials and cargo placed on the load support section 2 to prevent them from shifting.

[0042] The second hook 8 is formed by bending a rod with a circular cross-section into a U-shape. The second hook 8 is attached to each of the pair of wheel support members 3 by sandwiching the end of the wheel support member 3 in the X-axis direction between the openings, with the U-shaped openings facing each other in the X-axis direction along the XY plane. The second hook 8 is attached to the wheel support member 3 by joining, for example, welding.

[0043] The movable projection 5 is a mechanism that acts as a stopper to prevent materials and loads placed on the load-receiving section 2 from rolling off. It is provided on each of the pair of wheel-receiving members 3, as 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 projections 5 face each other (i.e., the X-axis direction) is perpendicular to the direction in which the slope portion 23 of the load-receiving section 2 slopes downward from the top 21 to the bottom 22 (i.e., the Y-axis direction).

[0044] The movable projection 5 has a projection 51, a movable part 52, and a support part 53.

[0045] The protruding support portion 51 has a rectangular plate-shaped main body portion 511 and a stopper portion 512 provided at the tip of the main body portion 511.

[0046] 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 fixing piece 521, a rotating piece 522, and a rotating shaft 523. For example, a hinge can be used as the movable part 52.

[0047] The fixing piece 521 of the movable part 52 is joined and fixed to the end face of the wheel support member 3 in the X-axis direction, for example by welding. In addition, the protruding support part 51 (specifically, the main body part 511) is attached to the rotating piece 522, for example by welding.

[0048] The rotating shaft 523 of the movable part 52 is arranged along the Y-axis direction, and the rotating shaft 523 causes the protruding support part 51, which is 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.

[0049] The support portion 53 is formed in a generally triangular plate shape in XZ plane view and is erected vertically along the XZ plane on one side of the main body portion 511 of the protruding support portion 51 (specifically, the side facing the opposing movable protruding support portion 5 in the X-axis direction).

[0050] With the above configuration, the protruding support portion 51 moves between a position where it protrudes onto the upper surface of the end of the wheel receiving member 3 in the X-axis direction (at this time, the support portion 53 contacts the upper surface of the wheel receiving member 3; see Figure 5(A)) and a position where it retracts laterally in the X-axis direction of the wheel receiving member 3 (at this time, the rotating piece 522 contacts the second hook 8; see Figure 5(B)). When the protruding support portion 51 is in the position where it protrudes onto the upper surface of the wheel receiving member 3, it protrudes above the upper surface of the top end portion 21 of the load receiving portion 2, that is, it protrudes above the mounting surface.

[0051] The movable projection 5 (especially the support portion 53) is adjusted so that when it is retracted laterally in the X-axis direction of the wheel support member 3, it does not protrude above the top surface 21 of the load receiving section 2 or the upper surface of the wheel support member 3 (in other words, the surface on which materials or luggage are placed) (see Figure 5(B)). This prevents the movable projection 5 from becoming an obstacle when loading or unloading materials or luggage onto or from the load receiving section 2 or wheel support member 3.

[0052] To prevent the movable projection 5 from rotating unexpectedly, a spring 54 (shown only in Figure 7) may be provided to maintain the projection 51 in a position where it protrudes from the upper surface of the end of the wheel support member 3 in the X-axis direction, or in a position where it is retracted laterally in the X-axis direction of the wheel support member 3.

[0053] Specifically, the spring 54 is interposed between the wheel support member 3 and the movable protruding support 5, with one end engaging with a first spring support shaft 541 fixed to the wheel support member 3 near its end in the X-axis direction, and the other end engaging with a second spring support shaft 542 fixed to the main body portion 511 of the protruding support portion 51 near its tip (i.e., near the abutment portion 512).

[0054] As shown in Figure 7(A), when the second spring bearing shaft 542 is positioned above the straight line connecting the first spring bearing shaft 541 and the rotation shaft 523, the spring 54 exerts a force that pulls the tip end of the protruding support portion 51, which rotates around the base end of the rotation shaft 523 as the axis of rotation, toward the upper surface of the wheel support member 3. This maintains the position in which the protruding support portion 51 extends outwards from the upper surface of the end of the wheel support member 3 in the X-axis direction.

[0055] On the other hand, as shown in Figure 7(B), when the second spring bearing shaft 542 is positioned below the straight 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 of the rotation shaft 523 as the axis of rotation, toward the end face of the wheel bearing member 3 in the X-axis direction. This maintains the position in which the protruding support portion 51 is retracted laterally in the X-axis direction of the wheel bearing member 3.

[0056] The trolley 1 described above is particularly suitable for transporting pipe materials (however, the items transported by the trolley 1 are not limited to pipe materials). Specifically, for example, if the pipe material to be transported is a single large-diameter pipe material 9A, it is placed on the loading section 2 so that the axial direction of the pipe material 9A is aligned with the X-axis direction.

[0057] In this case, as shown in Figure 8, the pipe material 9A is supported and held stably by the recess formed by the bottom 22 and the pair of slope portions 23 of the load-receiving portion 2, thereby preventing it from rolling off the load-receiving portion 2.

[0058] In this case, the load-receiving section 2 is formed symmetrically with respect to a straight line along the Z-axis that passes through the center Cy of the distance Lw along the Y-axis between the contact points Gw of the wheels 6 on the ground surface G when the radial direction of the wheels 6 is aligned with the XZ-axis (see Figures 3 and 4). Therefore, the center of gravity of the pipe material 9A in the YZ-plane view (in other words, the position of the axis of the pipe material 9A along the X-axis in the YZ-plane view) lies on the straight line along the Z-axis.

[0059] Furthermore, depending on the axial dimensions of the pipe material 9A, multiple trolleys 1 may be arranged and used, for example, by positioning trolleys 1 at each end of the pipe material 9A in the axial direction. In addition, the pipe material 9A placed on the load receiving section 2 with its axial direction aligned with the X-axis is secured by fastening with a lashing belt / cargo securing belt (not shown) using, for example, a pair of first hooks 7.

[0060] Furthermore, if the pipe material to be transported consists of multiple small-diameter pipe materials 9B, they are placed on the top surface 21 of the load receiving section 2 so that the axial direction of the pipe material 9B is aligned with the Y-axis direction, and are also placed directly on the wheel receiving member 3 (that is, the upper surface of the wheel receiving member 3 also functions as a surface for placing materials or cargo).

[0061] In this case, as shown in Figure 9, the movable projection 5 (specifically, the projection 51 having the abutment 512) acts as a support (in other words, a stopper) for the pipe material 9B, and the pipe material 9B is prevented from rolling off the load receiving section 2 or the wheel receiving member 3 by striking against the movable projection 5 (specifically, the abutment 512), receiving and supporting it. Depending on the axial dimensions of the pipe material 9B, multiple trolleys 1 may be arranged and used, for example, by placing trolleys 1 at positions near both ends of the pipe material 9B in the axial direction. Furthermore, the pipe material 9B placed on the load receiving section 2 with its axial direction aligned with the Y-axis is secured by fastening with lashing belts / cargo securing belts (not shown) using, for example, the second hooks 8 (a total of 4 in the example shown in the figure).

[0062] (Calculation of tipping resistance performance) This calculation determines the tipping resistance performance of the trolley 1 when a large-diameter pipe 9C, whose axis direction is aligned with the X-axis direction, is placed on the load-receiving section 2 of the trolley 1. Here, we take the example where the radial direction of the wheels 6 is aligned with the XZ plane (in Figure 10, one wheel 6 is shown as a dashed line), the distance Lw along the Y-axis direction between the contact points Gw of the wheels 6 on the ground surface G is 460 mm, and the diameter of the pipe 9C is 762 mm.

[0063] We will consider the most severe conditions for tipping over, and here we will examine the state in which the pipe material 9C is placed on the load-receiving section 2 so that its axial direction is aligned with the X-axis direction, and the radial direction of one of the wheels 6 is aligned with the YZ plane, as shown in Figure 10. We will also examine the state in which the trolley 1 is moved together with the pipe material 9C from a state in which the trolley 1 is completely stopped (i.e., the wheels 6 are completely stopped).

[0064] When the radial direction of the wheel 6 is aligned with the YZ plane, the distance between the center of gravity Cg of the pipe material 9C in the YZ plane view (in other words, the position of the axis of the pipe material 9C along the X-axis in the YZ plane view) and the contact point Gp of the wheel 6 with the ground surface G becomes shorter compared to when the radial direction of the wheel 6 is aligned with the XZ plane (the dashed line representing the wheel 6 in Figure 10).

[0065] In the above state, the angle θ between the center of gravity Cg of the pipe material 9C in a YZ plane view and the contact point Gp of the wheel 6, which is radially aligned with the YZ plane, with respect to the contact surface G of the bogie 1 / wheel 6, is 19.4°.

[0066] The formula for determining the horizontal load P [kg] acting at the height of the center of gravity Cg in the YZ plane view of pipe material 9C, which could cause the trolley 1 to tip over, is expressed as Equation 2 below, where w [kg] is the weight of pipe material 9C. In the example shown in Figure 10, θ = 19.4°. (Math 2) tanθ = P / w

[0067] Therefore, by adjusting the dimensions of each part of the trolley 1 to satisfy the following equation 3, the trolley 1 will not tip over. (Math. 3) P < w×tanθ Here, P: horizontal load acting on the height of the center of gravity in the YZ plane view of the pipe material. w: Weight of the pipe material θ: The center of gravity of the pipe material in the YZ plane view relative to the contact surface of the trolley / wheels. The angle connecting the wheel's contact point to the ground when the radial direction is aligned with the YZ plane.

[0068] Regarding equation 2 above, the horizontal load P changes depending on the weight w of the pipe material 9C (specifically, the length of the pipe material 9C in the axial direction). Therefore, calculating the horizontal load P for each axial length of the pipe material 9C and each weight w of the pipe material 9C yields the results shown in Table 1 below. [Table 1]

[0069] Cart 1 will not tip over unless subjected to a horizontal load greater than the horizontal load P calculated above. Referring to "Design Strength of Handrails" (Ministry of Land, Infrastructure, Transport and Tourism website), the horizontal force exerted by a person pushing an object is estimated to be 100-150 kg / m. Assuming an average human shoulder width of 0.6m, this translates to 60-90 kg / person. Applying this value to Table 1 above yields Table 2 below. [Table 2]

[0070] Based on the above, when loading pipe material 9C with a diameter of 762 mm, caution is required when two or more people are working on it if the length of pipe material 9C is 2 m, and caution is required when three or more people are working on it if the length of pipe material 9C is 3 m, but in other cases the risk of the trolley 1 tipping over is small.

[0071] According to the trolley 1 of this embodiment, the load-receiving section 2, which constitutes a part of the loading surface on which materials and luggage are placed, has top ends 21 at both ends, a bottom part 22 in the middle, and sloped sections 23 that slope downward from each of the top ends 21 toward the bottom part 22. As a result, the recess formed by the bottom part 22 and the pair of sloped sections 23 of the load-receiving section 2 can support materials and luggage (especially pipe materials 9A placed so that their axial direction is aligned with the X-axis direction), making it possible to transport materials and luggage while stably holding them so that they do not roll off the load-receiving section 2.

[0072] According to the embodiment of the trolley 1, a movable projection 5 is provided at the end of the loading surface on which materials and luggage are placed, and moves between a position that protrudes above the loading surface and a position that does not protrude above the loading surface. As a result, the movable projection 5 acts as a stopper (in other words, a brace) for materials and luggage placed on the loading section 2 and wheel support member 3, making it possible to transport materials and luggage stably while holding them in place so that they do not roll off the loading section 2 and wheel support member 3 (in other words, the loading surface on which materials and luggage are placed). Furthermore, it is possible to prevent the movable projection 5 from becoming an obstacle when loading or unloading materials and luggage onto the loading section 2 and wheel support member 3.

[0073] According to the trolley 1 of this embodiment, the movable projection 5 acts as a support for objects moving in a direction perpendicular to the direction of the downward slope of the slope portion 23 of the load receiving portion 2 (i.e., the direction from each of the top portions 21 toward the bottom portion 22; i.e., the Y-axis direction) (i.e., the X-axis direction). For example, when transporting a single large-diameter pipe material 9A, the recess formed by the bottom portion 22 and the pair of slope portions 23 of the load receiving portion 2 can be used to stably hold and transport the large-diameter pipe material 9A so that it does not roll off the load receiving portion 2. Also, when transporting multiple small-diameter pipe materials 9B, the movable projection 5 can be used to stably hold and transport the small-diameter pipe materials 9B so that they do not roll off the load receiving portion 2 or the wheel receiving member 3.

[0074] According to the trolley 1 of this embodiment, since the first hook 7 and the second hook 8 are attached, it is possible to tighten and secure materials and luggage placed on the mounting surface to prevent them from collapsing.

[0075] The first hook 7 is also used when multiple trolleys 1 are stacked, as shown in Figure 11. Specifically, one end of a cargo securing device 11 (e.g., a lashing belt, a cargo securing belt) is engaged with the first hook 7 of the bottommost trolley 1 among the multiple stacked trolleys 1 via a hook 11a, and the cargo securing device 11 is passed through each of the first hooks 7 of each of the multiple stacked trolleys 1, and the cargo securing device 11 is passed across the upper surface of the top end 21 of the load receiving section 2 of the topmost trolley 1 among the multiple stacked trolleys 1 on the opposite side in the Y-axis direction, and furthermore (on the side not visible in Figure 11) the cargo securing device 11 is passed through each of the first hooks 7 of each of the multiple stacked trolleys 1, and the other end of the cargo securing device 11 is engaged with the first hook 7 of the bottommost trolley 1 among the multiple stacked trolleys 1 via a hook 11a. This makes it easy to tie and secure multiple trolleys together in a stacked state, enabling stable and safe transport.

[0076] In the example shown in the figure, the upper plate (or top plate) of the wheel support member 3 has an opening wider than the width of the wheel 6 (see, for example, Figure 1). Therefore, when multiple trolleys 1 are stacked as shown in Figure 11, each of the four wheels 6 of the upper trolley 1 is positioned within the opening in the upper plate of the wheel support member 3 of the lower trolley 1 (the wheels 6 are placed on the top plate 61 of the wheels 6 of the lower trolley 1), thereby restricting the movement of the wheels 6 of the upper trolley 1 in the front, back, left, and right directions. This prevents the stacked trolleys 1 from collapsing and ensures that the stacked state of the multiple trolleys 1 is stably maintained.

[0077] Although embodiments of this invention have been described above, the specific configuration is not limited to the embodiments described above, and any design changes, etc., that do not depart from the spirit of this invention are also included.

[0078] For example, in the above embodiment, the load-receiving portion 2 is provided only on the intermediate portion of the wheel-receiving member 3 in the X-axis direction, but the load-receiving portion 2 may be provided over the entire length of the wheel-receiving member 3 in the X-axis direction. In this case, the protruding support portion 51 moves between a position where it protrudes onto the upper surface of the X-axis end of the top end portion 21 of the load-receiving portion 2 (at this time, the support portion 53 contacts the upper surface of the top end portion 21) and a position where it retracts laterally in the X-axis direction of the top end portion 21 of the load-receiving portion 2 and the wheel-receiving member 3 (at this time, the rotating piece 522 contacts the second hook 8). In other words, the movable protruding support portion 5 is provided at the end of the mounting surface on which materials or luggage are placed and moves between a position where it protrudes above the mounting surface (in other words, a protruding position) and a position where it does not protrude above the mounting surface.

[0079] In the above embodiment, the movable projection 5 has a projection 51, a movable part 52, and a support part 53, and the projection 51 rotates by the rotation axis 523 of the movable part 52. However, the specific configuration and mechanism of the movable projection in this invention is not limited to the movable projection 5 in the above embodiment. The movable projection is provided at the end of the mounting surface (the load receiving part 2 or wheel receiving member 3 in the above embodiment) and can change between a position / posture / state that protrudes above the mounting surface and a position / posture / state that does not protrude above the mounting surface.

[0080] Alternatively, the movable projection 5 may be omitted (see Figures 11 to 14). In this case as well, the recess formed by the bottom 22 and the pair of slope portions 23 of the load-receiving section 2 can support materials and luggage (especially pipe materials 9C placed so that their axial direction is aligned with the X-axis direction), making it possible to transport materials and luggage while stably holding them so that they do not roll off the load-receiving section 2.

[0081] As shown in Figures 11 to 14, the trolley 1 may have a pipe insertion section 10 into which a pipe (such as a single pipe or steel pipe; not shown) whose axial direction is along the Z-axis direction (i.e., vertical direction) can be inserted and removed. The pipe insertion section 10 has an insertion hole 10a whose axial direction is along the Z-axis direction, and a receiving plate 10b is provided horizontally along the XY plane at the lower end of the insertion hole 10a. As a result, the pipe inserted vertically from the upper end opening of the insertion hole 10a is supported by abutting against the receiving plate 10b. The pipe inserted into and supported by the insertion hole 10a prevents materials and luggage placed on the loading section 2 from rolling off the loading section 2, or it can be used as an operating rod that can be grasped and function like a handle when moving the trolley 1.

[0082] In the examples shown in Figures 11 to 14, the pipe insertion part 10 is attached to the end of the wall portion 24 of the load receiving portion 2 in the X-axis direction. However, the mounting position of the pipe insertion part 10 is not limited to the position shown in the examples in Figures 11 to 14, and may be a position shifted in the X-axis direction from the position shown in the examples in Figures 11 to 14. The pipe insertion part 10 may also be attached to the wheel receiving member 3. Furthermore, in the examples shown in Figures 11 to 14, one pipe insertion part 10 is attached to one side in the Y-axis direction (a total of two), but two or more pipe insertion parts 10 may be attached to one side in the Y-axis direction (a total of three or more). [Explanation of Symbols]

[0083] 1 cart 2. Receiving Section 21 Top surface 22 Bottom 23 Slope section 24 Wall 3 Wheel support member 4 Beam members 5 Movable protrusion branch 51 Protrusion support part 511 Main body 512 Dead end 52 Moving parts 521 Fixed piece 522 Rotating Piece 523 Rotation axis 53 Support part 6 wheels 61 Top plate (mounting base) 7. The first hook 8. The second hook 9A Large diameter pipe material 9B Small diameter pipe material 9C pipe material 10. Pipe insertion part 10a Insertion hole 10b Support plate 11. Cargo securing devices 11a Hook

Claims

1. The load-receiving portion, which constitutes at least a part of the mounting surface, has top ends at both ends, a bottom in the middle, and slopes that slope downward from each of the top ends towards the bottom. At both ends of the mounting surface, in a direction perpendicular to the downward slope of the slope portion, there are movable projections that move between a position that protrudes above the mounting surface and a position that does not protrude above the mounting surface. A trolley characterized by the following features.

2. A hook is attached to the aforementioned mounting surface for engaging a load securing device to fasten and fix the materials placed on it so that they do not collapse. The trolley according to feature 1.

3. The end of the cargo securing device is engaged with the hook via a hooking device, and the cargo securing device is passed through each of the hooks on each of the multiple stacked trolleys, thereby binding and securing them together in a stacked state. The trolley according to feature 2.

4. A pipe insertion section is attached into which a pipe whose axis is aligned vertically can be freely inserted and removed. A trolley according to any one of the features 1 to 3.

5. The dimensions of each part of the trolley are adjusted to satisfy the following equation 1. (Math. 1) P < w×tanθ Here, P: Horizontal load [kg] acting on the height of the center of gravity in a cross-sectional view along the direction of the downward slope of a pipe material placed on the load-receiving section such that its axial direction is perpendicular to the direction of the downward slope. w: Weight of pipe material [kg] θ: An angle connecting the center of gravity in a cross-sectional view of the pipe material along the direction of the downward slope, with respect to the contact surface of the trolley, and the contact point of the wheel, whose radial direction is along the direction of the downward slope. A trolley according to any one of the features 1 to 4.

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