Dolly

Abstract

To provide a dolly with casters, which is made lightweight by using a foamed resin and has strength sufficient for practical use.SOLUTION: A dolly has: a foamed resin board; an insert nut embedded in the foamed resin board and located so that an upper end of a head portion does not protrude from an upper surface of the foamed resin board and so that a lower end of a leg portion does not protrude from a lower surface of the foamed resin board; a fitting seat disposed on a lower surface side of the foamed resin board; a caster having a wheel rotatably supported via a wheel supporting part fitted on the fitting seat; and a male screw screwed into the insert nut to fix the fitting seat on the lower surface side of the foamed resin board.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a dolly for carrying loads. [Background technology]

[0002] 2. Description of the Related Art Conventionally, efforts have been made to achieve both lightness and strength in trucks for carrying loads, that is, to reduce the structural weakness that accompanies lightness.

[0003] For example, in Patent Document 1, a synthetic resin foam is injected into a hollow housing with a top plate surrounded on all sides by hard board material, heated to foam, the hollow part of the housing is filled with the synthetic resin foam, and then cooled and hardened, and the housing filled with the foamed resin is used as a loading platform member, thereby reducing the weight of the base for a trolley and ensuring its strength. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 7-205994 Summary of the Invention [Problem to be solved by the invention]

[0005] However, Patent Document 1 does not disclose casters or screw holes or other engaging parts for attaching casters on the cabinet with a top plate itself. To make the loading platform member of Patent Document 1 function as a cart, it would be necessary to set the cabinet with a top plate filled with foamed synthetic resin as a base for placing cargo on a separately prepared carrier with casters. Such a cart is not only inconvenient to use, but also makes the weight of the carrier with casters a detrimental factor to reducing weight.

[0006] Furthermore, the housing with a top plate disclosed in Patent Document 1 is formed by injecting a foamable synthetic resin into the housing, heating it to foam, filling the hollow portion of the housing with the foamable synthetic resin, and then cooling and hardening it. This process requires equipment such as a foamable synthetic resin mixing facility, a foamable synthetic resin injection device, and a relatively large heat treatment furnace capable of precise temperature control, which poses a manufacturing cost problem of requiring a relatively high capital investment.

[0007] Furthermore, in the above-described process, when the foamed synthetic resin that has been heated and foamed inside the housing and that has filled the housing at a relatively high temperature is cooled and hardened, the foamed synthetic resin shrinks, causing separation between the inner wall surface of the housing and the surface of the foamed synthetic resin, and unavoidably creating a certain amount of voids. This reduces the force that the foamed synthetic resin uses to support the housing from the inside, which has a negative effect on the strength of the housing as a whole. There is also the problem that it is difficult to perform non-destructive testing to determine the presence and extent of voids inside the housing and to eliminate low-quality products during product shipping inspections, etc.

[0008] In view of the above, an object of the present disclosure is to provide a cart with casters that is lightweight using foamed resin and has sufficient strength for practical use. [Means for solving the problem]

[0009] The first embodiment of the trolley comprises a foam resin board, an insert nut embedded in the foam resin board and positioned so that the upper end of the head does not protrude above the upper surface of the foam resin board and the lower end of the leg does not protrude above the lower surface of the foam resin board, a caster having a mounting seat placed on the lower surface of the foam resin board and a wheel rotatably supported via a wheel support portion attached to the mounting seat, and a male screw that threads onto the insert nut and fixes the mounting seat to the lower surface side of the foam resin board. [Effects of the Invention]

[0010] According to the present disclosure, it is possible to provide a lightweight cart with casters that is strong enough for practical use. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1(A) is a front view illustrating a carriage according to a first embodiment, and FIG. 1(B) is a bottom view illustrating the carriage. [Figure 2] FIG. 2 is a partial cross-sectional view taken along the line S2-S2 in FIG. [Figure 3] FIG. 2 is an exploded cross-sectional view of an insert nut and a male screw that are applied to the bogie according to the first embodiment. [Figure 4] Fig. 4(A) is a plan view illustrating that the dolly according to the first embodiment can move in the depth direction, Fig. 4(B) is a plan view illustrating a state in which the dolly is rotated 45° clockwise with respect to Fig. 4(A), and Fig. 4(C) is a plan view illustrating that the dolly can move in the width direction with a further rotation of 45° clockwise with respect to Fig. 4(B). [Figure 5] FIG. 2 is a side view illustrating a method for transporting a carriage according to the first embodiment. [Figure 6] 3 is a partial cross-sectional view illustrating a bogie according to a second embodiment, taken from a viewpoint corresponding to that of FIG. 2. FIG. [Figure 7] FIG. 10 is a side view illustrating a carriage according to a third embodiment. [Figure 8] FIG. 11 is a top perspective view showing a state in which the handle is attached and detached from the dolly according to the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] An example of an embodiment of the technology of the present disclosure will be described below with reference to the drawings. The same reference numerals are used to designate the same components and parts in the drawings. The dimensional proportions in the drawings are exaggerated for the sake of explanation and may differ from the actual proportions.

[0013] Arrow D in the figure indicates the length direction (depth direction) of the platform of the cart, and arrow W indicates the width direction (width direction) of the platform of the cart. Arrow H indicates the vertical direction, which is the up-down direction of the cart in an orientation where the depth direction and width direction are horizontal. The depth direction, width direction, and up-down direction are perpendicular to one another. In this specification, the above directions will be used for explanation, but the orientation of the cart is not limited to these directions.

[0014] <Configuration of the first embodiment> 1(A) and 1(B), the dolly 10 according to this embodiment is a dolly with casters attached to a board, a so-called flatbed hand truck. The dolly 10 can travel on a floor surface GR with cargo loaded on the loading surface. The dolly 10 has a foam resin board 20, an insert nut 30, a caster 40, and a male screw 50.

[0015] (Foam resin board) The foam resin board 20 is a rectangular board with lengths L in both the depth and width directions. The planar shape of the foam resin board 20 is not limited to a rectangle with equal lengths in the depth and width directions, and may be a rectangle with different lengths in the depth and width directions or any other shape as long as it has the required cargo loading surface. The foam resin board 20 has a board thickness of T. The foam resin board 20 is formed from foamed resin and functions as a loading platform for the dolly 10. The foam resin board 20 is, for example, polystyrene foam with an expansion ratio of approximately 60 times. The foam resin board 20 includes a loading surface protective sheet 22, a back protective sheet 24, and an embedded portion 26. The loading surface protective sheet 22 and the back protective sheet 24 are examples of thin-film protective portions.

[0016] ((Protection Department)) 2, the loading surface protection sheet 22 and the back surface protection sheet 24 are attached to the loading surface side surface layer portion 20H and the back surface side surface layer portion 20T opposite the loading surface side surface layer portion 20H of the foam resin board 20. In this embodiment, the loading surface protection sheet 22 and the back surface protection sheet 24 are both PVC sheets having a thickness T2 to impart water resistance, acid resistance, alkali resistance, or solvent resistance.

[0017] The protective portions of the loading surface protective sheet 22 and the back surface protective sheet 24 are not limited to PVC sheets. For example, the protective portion may be formed by immersing the foam resin board 20 in a coating solution or by spraying the coating solution onto the foam resin board 20 to form a coating film, followed by drying. Alternatively, the protective portion may be formed by heating and melting the loading surface side surface layer 20H or the back surface side surface layer 20T of the foam resin board 20 and then solidifying the surface layer. Furthermore, the protective portions of the loading surface protective sheet 22 and the back surface protective sheet 24 may be attached not only to the loading surface and the back surface, but also to the entire periphery or a portion of the foam resin board 20. In the present invention, the provision of the protective portion is desirable but not essential. For example, the protective portion may be omitted when the foam resin board 20 has a low expansion ratio and is made of a relatively robust material, or when the dolly is used to transport relatively light loads and there is little risk of the surface being damaged by impact during loading and unloading.

[0018] ((embedded part)) 2, the embedded portion 26 is a stepped opening that penetrates in the up-down direction from the loading surface side surface layer portion 20H to the back surface side surface layer portion 20T of the foam resin board 20. A plurality of embedded portions 26 are provided in the foam resin board 20. Each embedded portion 26 has a stepped surface 26A facing upward on the loading surface side surface layer portion 20H side.

[0019] (insert nut) As shown in FIG. 2, the insert nut 30 is a stepped nut embedded in the embedded portion 26 of the foam resin board 20 from the loading surface side surface layer 20H toward the opposite back surface side surface layer 20T. The insert nut 30 is formed slightly smaller in the width and depth directions than the embedded portion 26. Furthermore, while the insert nut 30 is embedded in the embedded portion 26, the gap GP between the insert nut 30 and the foam resin board 20 is filled with adhesive B. In other words, the insert nut 30 is adhered to the foam resin board 20 with adhesive B. In the present invention, the use of adhesive B is desirable but not essential.

[0020] A plurality of insert nuts 30 are provided corresponding to the embedded portions 26. Specifically, the insert nuts 30 are provided corresponding to the mounting positions of the casters 40 described below.

[0021] As shown in FIG. 3, the insert nut 30 includes a head portion 32, a leg portion 34, and a female thread portion 36.

[0022] ((head)) The head 32 is cylindrical with a bottom that extends in the vertical direction and is open downward. The head 32 is located on the loading surface side surface layer portion 20H side and functions as the head of the insert nut 30 (see FIG. 2). The head 32 is located closer to the loading surface side surface layer portion 20H than the stepped surface 26A of the embedded portion 26. The upper end 32A (see FIG. 2) of the head 32 is located so as not to protrude beyond the loading surface protective sheet 22 of the foam resin board 20. More specifically, the upper end 32A is located so as not to protrude beyond the loading surface side surface layer portion 20H of the foam resin board 20. In addition, the upper end 32A is flat.

[0023] The upper end 32A does not necessarily have to be flat, and may have any shape, such as a hemispherical (dome-like) shape. In this case, if there is a gap between the upper end 32A and the loading surface side surface layer portion 20H or the loading surface protection sheet 22 in the embedded portion 26, the gap may be filled with another member.

[0024] ((leg)) The leg portion 34 is cylindrical and extends in the vertical direction, and is formed integrally with the head portion 32 so that the head portion 32 is positioned above it. The leg portion 34 and the head portion 32 share a central axis along the vertical direction. The outer diameter of the leg portion 34 is smaller than the outer diameter of the head portion 32. That is, the boundary between the leg portion 34 and the head portion 32 (the area surrounding the stepped surface 26A of the embedded portion 26 in the foam resin board 20) appears as a stepped shape of the insert nut 30, and the head portion 32 has a larger diameter than the leg portion 34. The lower end 34A (see FIG. 2) of the leg portion 34 is positioned so as not to protrude beyond the rear protective sheet 24 of the foam resin board 20. More specifically, the lower end 34A is positioned so as not to protrude beyond the rear surface layer portion 20T of the foam resin board 20. The lower end 34A is also flat.

[0025] The lower end 34A does not necessarily have to be flat, and for example, the outer periphery may be chamfered.

[0026] ((female thread part)) 3, the female thread portion 36 is a thread formed on the cylindrical inner peripheral surfaces of the head 32 and the leg portion 34, extending from the lower end 34A of the leg portion 34 toward the upper end 32A of the head 32. The female thread portion 36 shares a central axis along the up-down direction with the leg portion 34 and the head 32. The length of the female thread portion 36 in the up-down direction (the depth from the lower end 34A to the bottom surface 36A) is designated as DI.

[0027] (caster) As shown in Fig. 2, a plurality of casters 40 are arranged on the back (underside) side of the foam resin board 20, and have the function of enabling movement of the foam resin board 20. In this embodiment, as shown in Fig. 1(B), a total of five casters 40 are arranged, including a mixture of two types of casters 40: swivel casters 40A arranged at the four corners CN1 of the foam resin board 20, and fixed casters 40B arranged at the center CN2 of the foam resin board 20.

[0028] The number of casters 40 is not limited to five. For example, the number of casters 40 may be six or more in order to improve load-bearing performance by shortening the distance between the casters 40. The number of casters 40 may also be three or four as long as the casters can withstand the load of the foam resin board 20 and the luggage LD (see FIG. 5) and still function as the cart 10. The material of the casters 40 may be either metal or resin.

[0029] The caster 40 includes a mounting seat 42 , a wheel support portion 44 , and a wheel 46 .

[0030] ((Mounting seat)) As shown in Fig. 2, the mounting seat 42 is a flat plate-like member having a thickness T1 and a plurality of screw holes 42H formed therethrough extending in the up-down direction. The mounting seat 42 is positioned so that the gap GP between the foam resin board 20 and the insert nut 30 is included inside the outer edge of the mounting seat 42. The mounting seat 42 is also positioned above the caster 40 and on the rear (lower) side of the foam resin board 20. In this embodiment, the mounting seat 42 is positioned on the lower surface of the rear protective sheet 24. The screw holes 42H are through holes through which male screws 50, which will be described later, are inserted, and are formed in the mounting seat 42 in accordance with the number and positions of the insert nuts 30. In this embodiment, four screw holes 42H are formed in each mounting seat 42.

[0031] ((wheel support part)) As shown in FIG. 2, the wheel support part 44 is attached to the mounting seat 42 and is a part that supports a wheel, which will be described later. In this embodiment, the wheel support part 44 corresponding to the swivel caster 40A has two rotation axes: a vertical rotation axis that determines the direction of travel of the carriage 10 on the floor surface GR (a rotation axis that determines a rotation angle θ that indicates the orientation of the caster with respect to the depth direction in FIG. 1), and a horizontal rotation axis that allows the carriage 10 to move forward and backward. The rotation angle θ can be in the range of 0° to 360°. In addition, the wheel support part 44 corresponding to the fixed caster 40B has one horizontal rotation axis that allows the carriage 10 to move forward and backward along a horizontal direction that is perpendicular to the vertical direction.

[0032] ((wheel)) The wheel 46 is disk-shaped and rotatably supported via the wheel support portion 44 .

[0033] As described above, the casters 40 enable the carriage 10 to select a direction of travel and to move forward and backward.

[0034] (male thread) 3, the male screw 50 is a screw having a head length DB. The male screw 50 is inserted into the screw hole 42H of the mounting seat 42 and threadedly engages with the insert nut 30, and the mounting seat 42 is fixed to the rear (lower) surface of the foam resin board 20 in an upward position, thereby attaching the caster 40 to the foam resin board 20.

[0035] 2, in the present embodiment, with the male screw 50 fixing the mounting seat 42, the male screw 50 is threaded into the insert nut 30 by a length DH. In other words, a gap DS is formed in the vertical direction between the tip 50A of the male screw 50 and the bottom surface 36A of the female thread portion 36 as a margin for absorbing vertical dimensional errors of the respective members.

[0036] The bogie 10 is constructed as described above.

[0037] <Effects of the First Embodiment> The effects of this embodiment will be described with reference to a comparative example.

[0038] (1) Although there have been proposals to utilize the lightweight properties of foamed resin for the purpose of weight reduction, foamed resin is relatively brittle compared to metal, wood, etc. When casters are attached directly to the foamed resin body using conventional caster attachment methods, the area around the attachment base is easily damaged by external forces such as impacts that are continuously transmitted from the caster during operation of the bogie. Therefore, as shown in Patent Document 1, for example, the areas where foamed resin can be used are limited when viewed from the perspective of the entire bogie structure. Furthermore, even when foamed resin is used in bogies, proposals have only been limited to structures that reinforce the periphery with a separate, hard, and relatively heavy member that is resistant to impacts, etc.

[0039] The cart 10 of this embodiment comprises a foam resin board 20, an insert nut 30 embedded in the foam resin board 20 and positioned so that the upper end 32A of the head 32 does not protrude beyond the loading surface side surface portion 20H of the foam resin board 20 and the lower end 34A of the leg 34 does not protrude beyond the back side surface portion 20T of the foam resin board 20, a mounting seat 42 arranged on the back side surface portion 20T side of the foam resin board 20, a caster 40 having a wheel 46 rotatably supported via a wheel support portion 44 attached to the mounting seat 42, and a male screw 50 that screws into the insert nut 30 and fixes the mounting seat 42 to the back side surface portion 20T side of the foam resin board 20.

[0040] An insert nut 30 is embedded in the foam resin board 20, with the upper end 32A of the head 32 located on the loading surface-side surface layer 20H of the foam resin board 20 and the lower end 34A of the leg 34 located on the back surface layer 20T of the foam resin board 20. The load of the luggage LD placed on the foam resin board 20 is then transmitted through the insert nut 30 to the wheel support portion 44 of the caster 40 arranged on the back surface layer 20T side of the foam resin board 20, and further transmitted through the wheel 46 to the floor surface GR on which the cart 10 moves. Therefore, the use of the foam resin board 20 reduces the weight of the cart 10, and even if the strength of the foam resin board 20 is low, the strength of the cart 10 can be increased by transmitting the load to the caster 40 with the insert nut 30.

[0041] (2) In the bogie 10 according to this embodiment, the head 32 of the insert nut 30 has a larger diameter than the leg 34. This prevents the insert nut 30 embedded in the foam resin board 20 from shifting in the vertical direction.

[0042] More specifically, in the dolly 10 according to this embodiment, the mounting seat 42 of the caster 40 is fixed by abutting against the back surface (bottom surface) of the foam resin board 20. In order to fix the mounting seat 42 to the back surface (bottom surface) of the foam resin board 20, the male screw 50 is inserted into the screw hole 42H of the mounting seat 42 and threaded into the female threaded portion 36 of the insert nut 30, and the bottom of the head of the male screw 50 presses the mounting seat 42 until it abuts (seats) against the back surface (bottom surface) of the foam resin board 20. Then, the male screw 50 is further screwed in, pulling the insert nut 30 toward the mounting seat 42, and the bottom surface 32B of the head 32 of the insert nut 30 presses against (seats) the back surface (bottom surface) of the foam resin board 20. When the insert nut 30 abuts (seats) against the stepped surface 26A of the embedded portion 26, and a certain torque is applied in the direction of further screwing the male screw 50, a tensile force is applied that stretches the screw in the vertical direction, slightly stretching the screw, and this restoring force acts as a fastening force between the underside 32B of the head 32 of the insert nut 30 and the bottom surface of the head of the male screw 50, firmly fixing the foamed resin part sandwiched between them and the mounting seat 42, thereby firmly fixing the caster 40 to the foamed resin board 20.

[0043] (3) In the dolly 10 according to this embodiment, the gap GP between the foam resin board 20 and the insert nut 30 is filled with adhesive B. However, in the present invention, neither the gap GB nor the adhesive B is required as long as the insert nut 30 has a size and shape that allows it to be inserted into the embedding portion 26. If the gap GP between the foam resin board 20 and the insert nut 30 is not filled with adhesive B, the pressing force of the load LD acting on the foam resin board 20 is not transmitted to the insert nut 30 but is directly received by the mounting seat 42 of the caster 40 below and transmitted to the floor surface GR on which the wheel 46 is in contact. Therefore, the pressing force of the load LD acts entirely as a vertical compressive force on the foam resin board 20. Furthermore, an upward reaction force acts on the caster 40 from the contact point of the caster 40. However, this reaction force is transmitted to the underside of the foam resin board 20 via the mounting seat 42 and ultimately to the bottom of the load LD, supporting the load. Furthermore, when the gap GP is not filled with adhesive B, the insert nut 30 is simply inserted into the embedding portion 26 and embedded, but when the male screw 50 is attached, the step surface 26A of the embedding portion 26 abuts against the underside 32B of the head 32 of the insert nut 30, and the fastening force of the male screw 50 fixes the insert nut 30 to the foam resin board 20, thereby preventing the entire insert nut 30 from shifting upward.

[0044] On the other hand, when the gap GP between the foam resin board 20 and the insert nut 30 is filled with adhesive B and firmly bonded, as in the trolley 10 of this embodiment, even if vertical vibrations are transmitted from the floor surface GR to the wheels 46 in addition to the reaction force of the pressing force from the luggage LD while the trolley 10 is moving, the embedded position of the insert nut 30 is further prevented from shifting and moving, and the compressive strength of the foam resin board 20 is also improved.

[0045] More specifically, when a cargo LD is loaded onto the dolly 10, the foam resin board 20 is pressed by the cargo LD. Because the entire opposing surfaces of the foam resin board 20 and the insert nut 30 are bonded and integrated with adhesive B filled in the gap GP, the pressing force is shared by the foam resin board 20 and the insert nut 30, and the insert nut 30 is further prevented from shifting relative to the foam resin board 20. Furthermore, the pressing force of the cargo LD is shared by the insert nut, which has a relatively high compressive strength, and the vertical compressive force acting on the foam resin board 20 is reduced. As a result, the apparent compressive strength of the foam resin dolly 10 is improved compared to when adhesive B is not used. Therefore, the above-mentioned effects are achieved.

[0046] (4) In the dolly 10 according to this embodiment, the casters 40 are disposed at the four corners CN1 and the center CN2 of the foam resin board 20. By disposing the casters 40 at the center CN2 of the foam resin board 20, the load acting on the foam resin board 20 is shared by the casters 40 disposed at the center CN2, compared to when the casters 40 are not disposed at the center CN2. This reduces the load on each caster 40 and halves the diagonal distance, which was the longest distance between the casters 40. This also reduces downward deflection of the foam resin board 20 due to the load, thereby improving load-bearing capacity. Furthermore, by designating the casters 40 disposed at the center CN2 as fixed casters 40B and the casters 40 disposed at the four corners CN1 as swivel casters 40A, the dolly 10 can be rotated around the fixed casters 40B as the center of rotation to transport cargo in the desired direction, even in a narrow space, such as a truck bed.

[0047] A more detailed description will be given using FIG. 4. FIG. 4(A) is a plan view illustrating that the dolly 10 according to the first embodiment is movable in the depth direction, and FIG. 4(B) is a plan view illustrating a state in which the dolly 10 is rotated 45° clockwise from FIG. 4(A). FIG. 4(C) is a plan view illustrating that the dolly 10 is movable in the width direction after being rotated a further 45° clockwise from FIG. 4(B). By providing the center portion CN2 as a fixed caster 40B whose rotation direction is restricted, the difficulty in moving the fixed caster 40B can be utilized to pivot (spin) at that position without moving the dolly 10. When such a pivot rotation is performed, sliding occurs in the rotational direction at the contact point of the wheel 46 of the fixed caster 40B. However, since the contact area at the contact point of the wheel is generally small, the sliding resistance is also relatively small, and in practice this sliding resistance does not interfere with the operation of the trolley 10. Furthermore, in order to prevent the contact point of the wheel 46 from getting caught in unevenness in the floor surface when pivoting, which would hinder the rotational movement, the rotational movement can be made smoother by applying a slight forward and backward movement to the trolley 10 while rotating.

[0048] Furthermore, in terms of supporting the load of the luggage LD, the dolly 10 supports the load by dividing it among the number of casters 40, with the contact point of the caster 40 that is in contact with the loading platform floor surface FL (see FIG. 5) as a fulcrum. The load that each caster 40 supports is divided in magnitude inversely proportional to the vertical distance between the center of gravity of the luggage LD and the contact point of the caster 40 (i.e., the caster 40 closer to the luggage supports more of the load), and if there is more than one luggage LD, each caster 40 will support a load that is the sum of the divided loads of each luggage LD.

[0049] (5) In the dolly 10 according to this embodiment, the foam resin board 20 is provided with a loading surface protective sheet 22 and a rear surface protective sheet 24 on at least the loading surface side surface layer portion 20H and the rear surface side surface portion 20T, respectively. This makes the foam resin board 20 less susceptible to damage caused by the luggage LD itself or by stones (chipping) from the floor surface GR.

[0050] (6) For example, it is conceivable that the caster 40 may repeatedly collide with and overcome the unevenness of the floor surface GR. In such a situation, the impact may cause a vibrational movement that shakes the caster 40 in the horizontal and vertical directions, and a force that tries to peel the mounting base 42 off the foam resin board 20 or pull out the fixing screw acts.

[0051] When the mounting base 42 is directly screwed to the underside of the foam resin board 20, the force of shaking the screw horizontally or up and down causes it to be screwed directly into the relatively fragile foam resin board 20, and since the sharp threads come into contact with the foam resin board 20, the screw may fall out relatively easily, causing the caster 40 to come off.

[0052] On the other hand, the dolly 10 according to this embodiment is configured so that the mounting seat 42 is fixed by threading a male screw 50 into an insert nut 30 extending in the thickness T direction of the foam resin board 20. As a result, even if a shaking force acts on the male screw 50 in the horizontal or vertical direction, the sharp threads of the male screw 50 do not come into direct contact with the foam resin board 20. Furthermore, because the insert nut 30 extends to a deep position in the foam resin board 20 (a position close to the surface layer portion 20H on the loading surface side), the shaking force acting on the male screw 50 in the horizontal or vertical direction is received three-dimensionally by the entire, relatively wide and smooth contact surface between the insert nut 30 and the foam resin board 20, and the force transmitted to the foam resin board 20 is dispersed and attenuated, thereby providing sufficient caster mounting strength for practical use.

[0053] (7) Furthermore, as shown in FIG. 5(A), when the dolly 10 according to this embodiment is loaded with a package LD placed on a pallet PL and transported to a box-shaped loading platform SP of a vehicle (not shown), the lightweight dolly 10 does not impose a significant burden on the vehicle's allowable load weight. Therefore, the package LD placed on the pallet PL can be transported by the vehicle without being removed from the dolly 10 onto the loading platform SP, thereby improving work efficiency. Furthermore, as shown in FIG. 5(B), even when the package LD placed on the pallet PL is loaded onto the loading platform floor FL of the loading platform SP, the lightweight dolly 10 is relatively easy for workers to carry and can be easily stored and carried in the gap between the wall SW of the loading platform SP and the package LD. By carrying the dolly 10 in this manner, it is possible to use the dolly 10 at a destination where transportation means such as a dolly or forklift are not available, thereby improving work efficiency. It is optional whether the dolly 10 is used in FIG. 5(A) or FIG. 5(B).

[0054] <Modification of the first embodiment> In the first embodiment, the loading surface side surface layer portion 20H, the back side surface layer portion 20T, the loading surface protection sheet 22, and the back side protection sheet 24 of the foam resin board 20 are flat surfaces, but this is not limited thereto. For example, the loading surface side surface layer portion 20H, the back side surface layer portion 20T, the loading surface protection sheet 22, and the back side protection sheet 24 may have small uneven portions (dimples) formed on the entire surface or in places of the surface that comes into contact with the luggage LD. This will create an appropriate frictional force between the luggage LD and the dolly 10, for example, when the luggage LD is packed in a manner that may cause it to slide on the dolly 10.

[0055] Second Embodiment Next, a dolly 210 according to a second embodiment will be described with reference to Fig. 6. The dolly 210 according to the second embodiment is basically the same as the dolly 10 according to the first embodiment, and a description of the common configuration will be omitted. Specifically, the dolly 210 differs from the dolly 10 in the mounting structure of the casters 40 to the foam resin board 220.

[0056] The cart 210 has a foam resin board 220, a reinforcing plate 260, casters 40, and male screws 250. Note that a description of the casters 40 will be omitted.

[0057] (Foam resin board) The foam resin board 220 is a board made of foam resin and having a board thickness t. The foam resin board 220 includes a loading surface protection sheet 222 and a back surface protection sheet 224.

[0058] (reinforcement plate) The reinforcing plate 260 is a plate disposed between the foam resin board 220 and the caster 40. Specifically, the reinforcing plate 260 is attached to the underside of the rear protective sheet 224 of the foam resin board 220 and is a hard resin plate having a female screw hole 262 at least on the underside. In this embodiment, as shown in FIG. 6 , the female screw hole 262 is formed as a through hole in the thickness direction of the reinforcing plate 260, but the female screw is formed only on the lower side in the thickness direction and no female screw is formed on the upper side in the thickness direction. When the male screw 250 is screwed into the female screw hole 262, a gap remains at the upper part of the thickness direction. Note that, in the present invention, the female screw hole formed in the reinforcing plate is not limited to this. The female screw hole may be formed over the entire length of the female screw hole. Furthermore, the reinforcing plate 260 may not be a through hole but may be an elongated hole of a required depth with an opening at the bottom. The reinforcing plate 260 is adhered to the underside of the foam resin board 220 with an adhesive (not shown).

[0059] In this embodiment, the reinforcing plate 260 is adhered to the foam resin board 220, but the present invention is not limited to this, and the reinforcing plate 260 may be attached to the foam resin board 220 by, for example, welding, screwing, or other attachment methods.

[0060] Furthermore, mounting seats for the casters 40 are disposed on the lower surface of the reinforcing plate 260. In other words, the reinforcing plate 260 is sandwiched between the foam resin board 220 and the mounting seats .

[0061] The reinforcing plate 260 is disposed on the underside of the foam resin board 220 in accordance with the location where the caster 40 is attached.

[0062] (male thread) The male screws 250 are threaded into the female screw holes 262 of the reinforcing plate 260, and fix the mounting seats 42 of the casters 40 to the underside of the reinforcing plate 260. The number of male screws 250 corresponds to the number of female screw holes 262. When the male screws 250 are threaded into the female screw holes 262, a gap is formed between the male screws 250 and the foam resin board 220. Well-known male screws may be used as the male screws 250.

[0063] <Effects of the Second Embodiment> The cart 210 of this embodiment has a foam resin board 220, a reinforcing plate 260 attached to the underside of the foam resin board 220 and having a female screw hole 262 provided on at least the underside, a mounting seat 42 arranged on the underside of the foam resin board 220, a caster 40 having a wheel 46 rotatably supported via a wheel support portion 44 attached to the mounting seat 42, and a male screw 250 that screws into the female screw hole 262 and fixes the mounting seat 42 to the underside of the reinforcing plate 260.

[0064] As a result, the carriage 210 can provide a carriage with a simpler structure and lower manufacturing costs in addition to the effects of the carriage 10 according to the first embodiment.

[0065] <Third embodiment> Next, a bogie 310 according to a third embodiment will be described with reference to Figures 7 and 8. The bogie 310 according to the third embodiment is basically the same as the bogie 10 according to the first embodiment, and a description of the common configuration will be omitted. Specifically, the bogie 310 has a structure in which a handle 370 is attached to the bogie 10. Note that the handle 370 described in this embodiment can also be attached to the bogie 210 according to the second embodiment.

[0066] As shown in Fig. 7, the cart 310 is operated by an operator OP with a package LD placed on a foam resin board 320. The cart 310 is movable on a floor surface GR by means of casters 40. The cart 310 is a so-called single-arm hand truck.

[0067] (Foam resin board) 8, the cart 310 includes a foam resin board 320. On a side surface 320S of the foam resin board 320, elongated holes 322 each having a circular cross section are formed so as to be spaced apart from each other by a distance IN in the width direction.

[0068] Although the elongated hole 322 is formed on one side surface 320S in the depth direction, this is not limited to this. For example, the elongated hole 322 may be formed on the other side surface or on all side surfaces. Also, although the elongated hole 322 has a circular cross-sectional shape, the present invention is not limited to this and the elongated hole 322 may have any cross-sectional shape, such as an ellipse, a rectangle, a polygon, or the like.

[0069] (Cylindrical member) As shown in FIG. 8 , the cylindrical member 360 is a hollow tube embedded along the elongated hole 322 from the side surface 320S of the foam resin board 320 toward the interior. The cylindrical member 360 is embedded with its outer wall surface in close contact with the inner wall surface of the elongated hole 322. When embedded in the elongated hole 322 of the foam resin board 320, the cylindrical member 360 is positioned so that its outer end surface is flush with the side surface 320S. Furthermore, although the outer periphery of the cross section of the cylindrical member 360 according to this embodiment is circular to match the cross-sectional shape of the elongated hole 322, the present invention is not limited thereto and may be, for example, an elliptical, rectangular, polygonal, or other arbitrary cross-sectional shape depending on the cross-sectional shape of the elongated hole provided in the side surface of the foam resin board. Furthermore, although the inner periphery of the cross section of the cylindrical member 360 is circular, the present invention is not limited thereto and may be, for example, an elliptical, rectangular, polygonal, or other arbitrary cross-sectional shape.

[0070] (handle) As shown in Fig. 8, handle 370 has a torii gate shape when viewed from the depth direction, and is an operating part that can be attached to and detached from side surface 320S of foam resin board 320. In Fig. 8, handle 370 shown by dashed lines shows a state in which it is attached to foam resin board 320, and handle 370 shown by solid lines shows a state in which it has been removed from foam resin board 320. Handle 370 includes anchor portion 372 and grip portion 374.

[0071] The anchor portion 372 is a pair of cylinders extending in the depth direction, positioned below the handle 370, and spaced apart in the width direction by a distance IN. One end of the anchor portion 372 is insertable into the interior of the tubular member 360. The anchor portion 372 transmits the operator's operating force to the foam resin board 320. Note that, although the outer periphery of the cross section of the anchor portion 372 according to this embodiment is circular to match the shape of the inner periphery of the cross section of the tubular member 360, the present invention is not limited thereto and may have any cross-sectional shape, such as an ellipse, rectangle, polygon, or any other shape, depending on the shape of the inner periphery of the cross section of the tubular member. Furthermore, although the anchor portion 372 is a hollow cylinder to reduce weight, the present invention is not limited thereto and may be a solid rod-shaped member.

[0072] The handle 374 is formed in a torii gate shape when viewed from the depth direction. Specifically, the handle 374 includes a pillar portion 374A and a grip 374B. The pillar portion 374A is a pillar-like body that extends in the vertical direction and rises from the front ends of the pair of anchor portions 372 in the depth direction while being spaced a distance IN from each other in the width direction. The grip 374B is a rod-like body located at the top of the handle 374 and is a member that connects the upper ends of the pair of pillar portions 374A in the width direction and is held by the operator OP.

[0073] Although the grip portion 374 according to this embodiment is formed in a torii gate shape, the present invention is not limited to this. For example, the grip of the grip portion may be formed in an arch shape. Alternatively, the upper ends of a pair of columnar portions may not be connected in the width direction, but the upper ends of each columnar portion may be bent toward the operator in the depth direction, and the bent portion may serve as the grip. Furthermore, the grip 374B of the grip portion 374 is rod-shaped, but may be variously modified as long as it has a shape that is easy for the operator OP to grasp. Furthermore, although the anchor portion 372 and the columnar portion 374A of the grip portion 374 according to this embodiment are each formed as a pair, the present invention is not limited to this. Alternatively, the grip may consist of a single anchor portion and a single columnar portion rising from it.

[0074] <Effects of the Third Embodiment> The cart 310 according to this embodiment has a hollow cylindrical member 360 embedded in a long hole 322 extending inward from the side surface 320S of the foam resin board 320, and a handle 370 having an anchor portion 372 at one end which can be inserted into the cylindrical member 360 and a grip portion 374 at the top rising from the other end of the anchor portion 372 which can be gripped by an operator OP.

[0075] As a result, in addition to the effects of the cart 10 according to the first embodiment, the cart 310 can be provided with good operability by providing the handle 370.

[0076] Further, the slots 322 may be formed on multiple side surfaces of the foam resin board 320, for example, on other side surfaces or on all side surfaces. In this case, the traveling direction of the cart 310 can be changed without moving the cart 310 by simply removing the handle 370 and inserting it into the cylindrical member 360 on the other side surface 320S.

[0077] In addition, the present disclosure can be configured by partially combining the configurations illustrated in the attached drawings. As described above, the present disclosure includes various embodiments not described above, and the technical scope of the present disclosure is defined only by the invention-specifying matters in the claims that are appropriate from the above description. [Explanation of symbols]

[0078] 10 carts 20 Foam resin board 20H Loading surface 20T Rear surface layer 22 Loading surface protection sheet 24 Back protection sheet 26 Embedded part 26A Step surface 30 Insert nut 32 Head 32A top end 32B Bottom 34 Legs 34A bottom end 36 Female thread 36A Bottom 40 Caster 40A Swivel Caster 40B fixed caster 42 Mounting seat 42H screw hole 44 Wheel support part 46 wheels 50 male thread 50A tip 210 Cart 220 Foam resin board 222 Loading surface protection sheet 224 Back protection sheet 250 male thread 260 Reinforcement plate 262 female screw hole 310 Cart 320 Foam resin board 320S side 322 slotted hole 360 Cylinder member 360 slot 370 Handle 372 Anchor part 374 Gripping part 374A Column 374B Grip θ rotation angle B. Adhesive CN1 Four corners CN2 central part DS Gap FL Cargo floor GP Gap GR floor surface IN Distance OP worker PL Pallet SP Cargo Bed SW wall LD Luggage t Plate thickness

Claims

1. A foam resin board, an insert nut that is embedded in the foam resin board and positioned so that the upper end of the head does not protrude from the upper surface of the foam resin board and the lower end of the leg does not protrude from the lower surface of the foam resin board; a caster including a mounting seat disposed on the underside of the foam resin board and a wheel rotatably supported via a wheel support portion attached to the mounting seat; a male screw that is screwed into the insert nut and fixes the mounting seat to the underside of the foam resin board; A trolley having:

2. The head of the insert nut has a larger diameter than the leg. The carriage according to claim 1 .

3. The insert nut is embedded in the foam resin board and adhered with an adhesive. The carriage according to claim 2.

4. A foam resin board, a reinforcing plate attached to the underside of the foam resin board and having a female screw hole at least on the underside; a caster including a mounting seat disposed on the underside of the foam resin board and a wheel rotatably supported via a wheel support portion attached to the mounting seat; a male screw that is threaded into the female screw hole and fixes the mounting seat to the lower surface of the reinforcing plate; A trolley having:

5. The bogie according to claim 4 , wherein the reinforcing plate is a hard resin plate.

6. The casters are arranged at the four corners and the center of the foam resin board. The bogie according to claim 1 or 4.

7. The foam resin board has thin film-like protective portions on at least the upper and lower surfaces. The bogie according to claim 1 or 4.

8. a hollow cylindrical member embedded in the foamed resin board from a side surface toward the interior thereof; a handle having an anchor portion whose one end can be inserted into the cylindrical member and a grip portion that rises from the other end of the anchor portion and can be gripped by an operator; 5. The bogie according to claim 1 or 4, comprising:

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