Dolly

Abstract

To provide a dolly that has a small number of components, is easy to assemble, and allows easy replacement of a central top plate, the replacement frequency of which is high.SOLUTION: A dolly 1 includes: an underframe 2 having front, rear, left, and right outer frame members 20A, 20B; a plurality of casters 3 provided on the lower side of the underframe 2; and a top plate 4 provided on the underframe 2 to form a loading surface. The underframe 2 further includes two intermediate frame members 20C fixed in parallel at a predetermined distance from each other at an intermediate portion in the length of the front, rear, or left and right outer frame members 20A. The top plate 4 has a central top plate 40A fixed between the two intermediate frame members 20C. The central top plate 40A is provided so as to be independently detachable from the top surface of the dolly 1.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a cart for carrying and transporting luggage and the like. [Background technology]

[0002] As shown in Patent Document 1, for example, a known transport cart includes a cart body (underframe) made up of front, rear, left and right frames and a plurality of subframes arranged inside these connected in a grid pattern, a plurality of casters attached to the underside of the cart body via caster mounting plates, and a top plate attached to the top of the cart body. The top plate is made up of, for example, a central top plate arranged in the center of the cart body and auxiliary top plates arranged on both sides of the central top plate. However, in the case of the above-mentioned bogie, the lattice-shaped bogie body has a large number of parts, which increases the number of assembly steps, making it difficult to reduce manufacturing costs.

[0003] Other transport trolleys are also known that have a central top plate that is designed to be strong in itself and that is connected to other components (for example, frame reinforcements, caster mounting plates, etc.) to form a unit, thereby eliminating part or all of the subframe of the trolley body and improving assembly ease. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-150737 Summary of the Invention [Problem to be solved by the invention]

[0005] The central top plate of the above-mentioned bogie is prone to damage during use and therefore needs to be replaced more frequently than other parts of the bogie. However, in the case of a unitized central top plate, it must be separated from the other parts when replacing it, and the work may require the cart to be turned upside down, which makes replacement difficult.

[0006] This invention has been made to solve the above problems, and aims to provide a trolley that has a small number of parts, is easy to assemble, and allows for easy replacement of the central top plate, which is replaced frequently. [Means for solving the problem]

[0007] In order to achieve the above object, the present invention comprises the following aspects.

[0008] 1) A cart having an underframe having outer frame members on the front, rear, left and right sides, a plurality of casters provided on the underframe, and a top plate provided on the underframe to form a loading surface, The underframe further includes two intermediate frame members that are secured in parallel at a predetermined interval between the longitudinal intermediate portions of the front and rear or left and right outer frame members, The top plate has a central top plate disposed and fixed between the two intermediate frame members, The central top plate is provided so as to be detachable independently from the top surface side of the cart.

[0009] 2) The central top plate has a top wall portion whose upper surface serves as a loading surface, and two side walls extending downward from both side edges of the top wall portion, The two intermediate frame members each have a vertical wall portion that can be aligned with the outer surface of each side wall portion of the central top plate, The cart of 1) above, wherein the two side wall portions of the central top plate are detachably attached to the vertical wall portions of the two intermediate frame members.

[0010] 3) Multiple casters are attached to caster mounting plates that are secured to the underside of the left and right or front and rear outer frame members so that they intersect with the central top plate when viewed from above, The central top plate further has an intermediate hanging wall portion extending downward from a widthwise intermediate portion of the top wall portion so as to be parallel to the two side wall portions, A cart as described in 2) above, in which a horizontal lower flange portion is provided at the lower edge of the intermediate hanging wall portion of the central top plate, which can be abutted against the upper surface of the caster mounting plate.

[0011] 4) A trolley as defined in 2) or 3) above, in which the two intermediate frame members have support protrusions that protrude from the lower edges of the vertical walls or the middle position of the height so as to face each other and support the lower edges of the two side walls of the central top plate.

[0012] 5) A bogie of 4) above, in which the lower edges of the two side walls of the central top plate are provided with horizontal lower flange portions that abut against the upper surfaces of the support protrusions of the vertical wall portions of the two intermediate frame members.

[0013] 6) A bogie of any one of 2) to 5) above, in which both end portions of the outer surfaces of the vertical wall portions of the two intermediate frame members are connected to the longitudinal intermediate portions of the front / rear or left / right outer frame members via curved plate-like connecting members that are L-shaped when viewed from above.

[0014] 7) A trolley as described in 6) above, wherein each of the two intermediate frame members further has an upper horizontal wall portion and a lower horizontal wall portion extending from the upper and lower edges of the vertical wall portion toward the opposite side of the central top plate, and the connecting member has a vertical width approximately equal to the vertical distance between the upper horizontal wall portion and the lower horizontal wall portion.

[0015] 8) A trolley according to any one of 1) to 7) above, further having an auxiliary top plate that is secured to the upper side of the intermediate frame member and the outer frame member facing it and is positioned so as not to overlap with the central top plate when viewed from above.

[0016] 9) A plurality of casters are attached to caster mounting plates that are secured to the underside of the left and right or front and rear outer frame members so as to intersect with the central top plate when viewed from above, The top plate further includes an auxiliary top plate that is secured to the upper sides of the intermediate frame member and the outer frame member facing the intermediate frame member and is arranged so as not to overlap with the central top plate when viewed from above, The cart of any one of 1) to 8) above, which is provided with a gap closing portion that closes the gap that occurs between the side edges of the auxiliary top plate and the caster mounting plate.

[0017] 10) The trolley of 9) above, wherein the gap blocking portion is a gap blocking wall portion formed integrally with the auxiliary top plate so as to extend downward from the side edge of the auxiliary top plate toward the side edge of the caster mounting plate.

[0018] 11) A trolley as described in 10) above, in which the gap blocking wall portion has a vertical wall portion extending downward from the side edge of the auxiliary top plate and a lower horizontal wall portion bent from the lower edge of the vertical wall portion to fit along the upper surface of the side edge of the caster mounting plate. [Effects of the Invention]

[0019] According to the bogie of this invention, the underframe is composed of outer frame members at the front, rear, left and right and two intermediate frame members, which reduces the number of parts and makes assembly easier.In addition, the central top plate is positioned between the two intermediate frame members and is detachable and attachable separately from the top side of the bogie, making replacement easy. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a perspective view of a bogie according to a first embodiment of the present invention. [Figure 2] FIG. [Figure 3] FIG. [Figure 4] FIG. 2 is a perspective view showing the cart with the central top plate separated. [Figure 5] FIG. 3 is a vertical cross-sectional view taken along line AA in FIG. 2. [Figure 6] FIG. 6 is an enlarged view of part D in FIG. 5. [Figure 7] FIG. 3 is a vertical cross-sectional view taken along line BB in FIG. 2. [Figure 8] FIG. 8 is an enlarged view of part E in FIG. 7. [Figure 9] FIG. 8 is an enlarged view of part F in FIG. 7. [Figure 10] FIG. 3 is a view taken along line CC in FIG. 2. [Figure 11] 11 is an enlarged view of part G in FIG. 10. FIG. [Figure 12] FIG. 10 is a perspective view of a truck according to a second embodiment of the present invention. [Figure 13] FIG. 10(a) is a perspective view showing an auxiliary top plate used in the carriage of the second embodiment, and FIG. 10(b) is a perspective view showing a modified example of the auxiliary top plate. [Figure 14] FIG. 8 is a vertical cross-sectional view of the bogie of the second embodiment, corresponding to FIG. 7. [Figure 15] 15 is an enlarged view of part H in FIG. 14. FIG. [Figure 16] 12 is a view corresponding to FIG. 11 of the bogie of the second embodiment. FIG. [Figure 17] FIG. 16 is a view corresponding to FIG. 15, showing another modified example of the auxiliary top plate used in the carriage of the second embodiment. [Figure 18] FIG. 16 is a view corresponding to FIG. 15, showing yet another modified example of the auxiliary top plate used in the carriage of the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0021] Next, an embodiment of the present invention will be described with reference to FIGS. In the following description, the top of FIG. 2 (plan view of the carriage) will be referred to as the "front", the bottom as the "rear", and "left and right" will refer to the left and right facing forward (left and right in FIG. 2).

[0022] First Embodiment As shown in Figures 1 to 3, a trolley (1) according to the first embodiment of the present invention includes an underframe (2) having front, rear, left and right outer frame members (20A) (20B), a plurality of casters (3) provided on the underframe (2), and a top plate (4) provided on the underframe (2) to form a loading surface.

[0023] The underframe 2 is the base of the bogie 1 and is formed in a roughly rectangular shape when viewed from above. The underframe 2 shown in the figure has a rectangular shape in plan view that is long from front to back, but it may also be a square or something close to a square, or a rectangular shape that is long from side to side. The outer frame members 20A, 20B on the front, rear, left and right sides of the underframe 2 are connected and integrated into a square shape via four corner members 20D. Each of the outer frame members 20A and 20B is formed from a member having a substantially rectangular cross section (see FIGS. 8 and 11). However, the shape of the outer frame members 20A and 20B is not limited to the above. The ends of the outer frame members (20A) and (20B) are inserted into connecting portions (201) consisting of a pair of vertical wall portions that protrude in the front-to-back and left-to-right directions from the corner members (20D), and are connected and fixed to the connecting portions (201) with bolts, nuts, etc. (see Figures 8, 11, etc.). Each corner member (20D) has a vertical cylindrical portion (202) (see Figures 1, 2, etc.). Although not shown, by inserting and connecting the lower end of a push rod made of a shaped material, pipe, or the like, or the lower end of an inverted U-shaped handle into this vertical cylindrical portion (202), the push rod or handle can be attached upright to the cart (1), and the cart (1) can be used as a push cart.

[0024] The underframe 2 also has two intermediate frame members 20C, one on the left and one on the right, that are parallel to each other and spaced a predetermined distance apart from each other at the midpoint of the length of the front and rear outer frame members 20A. In the case of the underframe 2 shown in the figure, the intermediate frame members 20C are spaced apart from each other at positions on the front and rear outer frame members 20A that divide the length of these members into approximately three equal parts, but are not limited to being at the same positions. The two intermediate frame members (20C) are symmetrical, and each has a vertical wall portion (21) extending in the front-to-rear direction, an upper horizontal wall portion (22) extending outward in the left-right direction from the upper edge of the vertical wall portion (21), and a lower horizontal wall portion (23) extending outward in the left-right direction from the lower edge of the vertical wall portion (21). Furthermore, each intermediate frame member (20C) has a support protrusion (211) extending inward in the left-right direction from the lower edge of the vertical wall portion (21) (or the intermediate position in height). In some cases, both or one of the upper horizontal wall portion (22) and the lower horizontal wall portion (23) can be omitted.

[0025] Both ends of the two intermediate frame members (20C) are connected to the longitudinal intermediate portions of the front and rear outer frame members (20A). In a preferred embodiment, both end portions of the left and right outer surfaces of the vertical wall portions (21) of the two intermediate frame members (20C) are connected to the longitudinal intermediate portions of the front and rear outer frame members (20A) via connecting members (6) that are curved plates that are L-shaped in a plan view. With this configuration, the front and rear outer frame members (20A) and the intermediate frame member (20C) can be connected together without interfering with the attachment and detachment of the central top plate (40A), which will be described later. The first vertical plate portion 61 of the connecting member 6 is connected to the inner wall portions of the front and rear outer frame members 20A using, for example, rivets. On the other hand, the second vertical plate portion 62 of the connecting member 6 is preferably connected to the vertical wall portion 21 of the intermediate frame member 20C at the same time as connecting the vertical wall portion 21 of the intermediate frame member 20C to the side wall portion 42 of the central top plate 40A using fastening parts, which will be described later. This configuration reduces the number of steps required to assemble the bogie 1 and also avoids the problem of interference with the vertical wall portion 21 of the intermediate frame member 20C, which may occur when connecting the above fastening parts using separate fastening parts, rivets, or the like. The connecting member 6 preferably has a vertical width approximately equal to the vertical distance between the upper horizontal wall portion 22 and the lower horizontal wall portion 23 of the intermediate frame member 20C. When the dolly 1 is used as a push dolly by attaching a push rod to the vertical cylindrical portion 202 of the corner member 20D of the underframe 2, a torsional force may act on the front and rear outer frame members 20A via the push rod. However, with the above-described configuration, the upper or lower edge of the connecting member 6 abuts against the lower horizontal wall portion 23 or upper horizontal wall portion 22 of the intermediate frame member 20C, thereby suppressing damage to the front and rear outer frame members 20A due to torsion.

[0026] The materials of the outer frame members 20A, 20B and the intermediate frame member 20C are not particularly limited, but are preferably made of light metal shaped members, more preferably made of aluminum alloy shaped members.

[0027] In the illustrated bogie (1), a total of six casters (3) are provided on the underside of the underframe (2). In other words, the illustrated bogie (1) is configured as a six-wheel bogie. More specifically, three caster mounting plates (5) are attached to the underside of the left and right outer frame members (20B) at a predetermined interval in the front and back directions, and casters (3) are attached to both the left and right sides of the underside of each caster mounting plate (5).

[0028] Each caster (3) consists of a top plate (31), a fork (32), an axle (33), a wheel (34), and a stopper (35). The top plate (31) is fixed to the underside of the caster mounting plate (5) with bolts, nuts, etc., so that the caster is provided below the frame (2) in a rollable manner (see Figures 8, 11, etc.). The number, arrangement, and structure of the casters 3 are not limited to the above embodiment and can be changed as appropriate. For example, of the six casters 3 of the illustrated dolly 1, the two middle casters 3 at the front and rear can be omitted to form a four-wheel dolly. In this case, the middle caster mounting plates 5 at the front and rear can also be omitted.

[0029] The caster mounting plate (5) is formed of a plate material that is long in the left-right direction. As shown in Figure 8 and other figures, the caster mounting plate (5) has one or more (two in the front and two in the front) grooves (51) that extend lengthwise and open upward in the middle of its width. The grooves (51) are designed to accommodate bolt heads (or nuts) for fixing the top plates (31) of the casters (3). The caster mounting plate (5) may also be provided with ribs (52) that extend downward from both end edges and / or the middle of its width (see Figure 8). As shown in Figure 11 and other figures, a step is formed in the lower wall portions of the left and right outer frame members (20B) so that the inner portions (203) are positioned higher than the outer portions by a height approximately equal to the thickness (vertical height) of the caster mounting plate (5). The ends of the caster mounting plate (5) are abutted from below against the inner portions (203) of the lower wall portions and connected and fixed by rivets or the like (see Figures 3, 11, etc.). Preferably, a predetermined intermediate portion of the caster mounting plate (5) is brought into contact with the lower horizontal wall portions (23) of the two intermediate frame members (20C) from below and connected and fixed with rivets or the like (see Figure 11, etc.). According to the above configuration, the left and right outer frame members (20B) and both intermediate frame members (20C) are connected via the caster mounting plate (5). Therefore, despite the small number of parts of the underframe (2), the strength of the entire underframe (2) can be increased, and the mounting strength of the caster mounting plate (5) is also improved.

[0030] The dolly (1) has a central top plate (40A) disposed and fixed between the two intermediate frame members (20C) as a top plate (4) constituting a loading surface. The central top plate (40A) is provided so as to be detachable independently from the upper surface side of the dolly (1). The central top plate (40A) is formed from a plate material extending in the front-to-rear direction and is attached to the underframe (2) so as to intersect with the caster mounting plate (5) in a plan view. This central top plate (40A) is preferably formed from a single material, and more preferably from an aluminum profile or the like, which is lightweight and has excellent strength. The central top plate (40A) has a top wall (41) whose upper surface serves as a loading surface, and two side walls (42) extending downward from both side edges of the top wall (41). When the central top plate 40A is placed between the two intermediate frame members 20C, the vertical wall portions 21 of the two intermediate frame members 20C fit along the outer surfaces of the side wall portions 42 of the central top plate 40A. The side wall portions 42 of the central top plate 40A are detachably attached to the vertical wall portions 21 of the intermediate frame members 20C by, for example, connecting them from the outside of the intermediate frame members 20C with fastening parts such as bolts and nuts. More specifically, for example, bolt holes are drilled in corresponding locations in the side wall portions 42 of the central top plate 40A, the vertical wall portions 21 of the two intermediate frame members 20C, and the second vertical plate portion 62 of the connecting member 6, and blind nuts 71 are fixed to the inner surfaces of the side wall portions 42 of the central top plate 40A around the bolt holes. Then, bolts 72 are inserted from the outside of the second vertical plate portion 62 of the connecting member 6 through bolt insertion holes in the second vertical plate portion 62, the vertical wall portion 21 of the intermediate frame member 20C, and the side wall portion 42 of the central top plate 40A, and then screwed into blind nuts 71, thereby connecting these portions 62, 21, and 42 together (see FIG. 4, etc.). In the above embodiment, the central top plate 40A can be easily attached and detached simply by attaching and detaching the bolts 72 from the top surface of the bogie 1. Note that fastening parts for attaching the central top plate 40A to the two intermediate frame members 20C are not limited to the blind nuts 71 and bolts 72 described above. Parts that form threads or parts that can be fastened by tapping screws or other such parts are preferred, but the fastening parts are not limited to these. The central top plate 40A is supported from below by support portions provided at predetermined locations on both intermediate frame members 20C. More specifically, the lower edges of the side wall portions 42 of the central top plate 40A are supported from below by support protrusions 211 formed on the lower edges (or intermediate positions in height) of the vertical wall portions 21 of both intermediate frame members 20C, as described above. In this state, the upper surface (loading surface) of the top wall portion 41 of the central top plate 40A is positioned approximately at the same level as the upper surfaces of the front, rear, left, and right outer frame members 20A and 20B. Preferably, horizontal lower flanges 421 are provided on the lower edges of the side wall portions 42 of the central top plate 40A, and the lower flanges 421 abut (are in surface contact with) the upper surfaces of the support protrusions 211 of both intermediate frame members 20C (see FIG. 6). The lower flanges 421 are not fixed to the support protrusions 211 or the caster mounting plates 5. The lower flanges 421 of the side wall portions 42 extend inward in the left-right direction so as to face each other. With this configuration, the central top plate 40A is more stably supported by both intermediate frame members 20C. Furthermore, the central top panel (40A) has an intermediate hanging wall portion (43) extending downward from the widthwise center of the top wall portion (41) so as to be parallel to the two side wall portions (42). A horizontal lower flange portion (431) is provided at the lower edge of the intermediate hanging wall portion (43) so as to abut against the upper surface of the caster mounting plate (5). The lower flange portion (431) is not fixed to the caster mounting plate (5). This configuration ensures sufficient load-bearing capacity without compromising the ease of replacement of the central top panel (40A). In the illustrated central top panel (40A), one intermediate hanging wall portion (43) is provided extending downward from the widthwise center of the top wall portion (41), but it is also possible to provide two or more intermediate hanging walls spaced apart in the width direction. In addition, in the illustrated intermediate hanging wall portion (43), the lower flange portion (431) has an inverted T-shape extending to both the left and right sides, but if, for example, two or more intermediate hanging wall portions (43) are provided, the lower flange portion (431) can also have an L-shape extending to either the left or right side.

[0031] In addition to the central top plate (40A), the cart (1) preferably has auxiliary top plates (40B) that are secured to the upper sides of the intermediate frame member (20C) and the opposite outer frame members (20B) and are arranged so as not to overlap the central top plate (40A) in a plan view. With this configuration, the auxiliary top plates (40B) can increase the area of ​​the loading surface without impairing the ease of attachment and detachment of the central top plate (40A). The auxiliary top plate (40B) is formed of a plate material extending to the left and right, and is preferably made of a light metal (more preferably an aluminum alloy). In the illustrated dolly (1), four auxiliary top plates (40B) are provided, two on each side of the central top plate (40A), spaced apart in the front and rear. As shown in FIG. 2 and other figures, the auxiliary top plates (40B) are installed so as not to overlap the three caster mounting plates (5) in a plan view. In other words, the portions of the caster mounting plates (5) to which the casters (3) are attached are not covered by the auxiliary top plates (40B) and are exposed on the upper surface of the dolly (1). When multiple dollies (1) are stacked one on top of the other for transportation or storage, the casters (3) of the upper dolly (1) are positioned above the exposed portions of the caster mounting plates (5) of the lower dolly (1). The number and arrangement of the auxiliary top plates (40B) are not limited to the above-described embodiment and can be modified as appropriate. For example, if the two casters (3) located in the middle of the front and rear of the six casters (3) shown in the figure are omitted to make a four-wheeled cart, an auxiliary top plate (40B) can also be installed above the two casters (3). 9, the auxiliary top plate (40B) has front and rear side edges (45) bent downward in an L-shape, and has a recessed groove (46) formed in the center of its width. In addition, the auxiliary top plate (40B) may have a plurality of downwardly protruding ribs (47) formed in the lower surface between the recessed groove (46) and the front and rear side edges (45). As shown in Figure 11 and other figures, a step is formed in the upper wall portions of the left and right outer frame members (20B) so that the inner portions (204) are positioned lower than the outer portions by a height approximately equal to the thickness of the auxiliary top plate (40B). The front and rear side edges (45) and one end portion of the recessed groove portion (46) of the auxiliary top plate (40B) are abutted from above against the inner portions (204) of the upper wall portions and are connected and fixed by tapping screws or the like (see Figures 2, 11, etc.). The front and rear side edges 45 and the other end of the recessed groove 46 of the auxiliary top plate 40B are abutted from above against the upper horizontal wall 22 of the intermediate frame member 20C and are connected and fixed with tapping screws or the like (see Figures 2, 11, etc.). The upper surface of the upper horizontal wall 22 of the intermediate frame member 20C is positioned below the upper surfaces of the front, rear, left, and right outer frame members 20A and 20B by a height approximately equal to the thickness (vertical height) of the auxiliary top plate 40B. With this configuration, the upper surface (loading surface) of the auxiliary top plate 40B is approximately flush with the upper surfaces of the front, rear, left, and right outer frame members 20A and 20B.

[0032] According to the bogie (1) of the first embodiment, the underframe (2) is composed of front, rear, left and right outer frame members (20A) (20B) and two intermediate frame members (20C), so that the number of parts is smaller than that of the conventional bogie shown in Patent Document 1, and it is possible to reduce the assembly man-hours and costs. Furthermore, the trolley (1) has a central top plate (40A) that is disposed between the two intermediate frame members (20C) and can be attached and detached independently from the top surface side of the trolley (1). Therefore, when replacing the central top plate (40A), there is no need to remove any parts other than the central top plate (40A) or turn the trolley (1) over, making the replacement of the central top plate (40A) extremely easy.

[0033] <Second embodiment> 12 to 18 show a truck according to a second embodiment of the present invention. The carriage (1X) of the second embodiment is substantially the same as the carriage (1) of the first embodiment shown in FIGS. 1 to 11, except for the following points. That is, the cart (1X) of this embodiment is provided with a gap closing portion (8) that closes the gap that occurs between the side edges of the auxiliary top plate (40BX) and the caster mounting plate (5). According to the above-mentioned trolley (1X), even when the load is a small item such as a machine part, the presence of the gap blocking portion (8) can reliably prevent the load from falling below the frame (2) through the gap between the side edges of the auxiliary top plate (40BX) and the caster mounting plate (5).

[0034] The gap blocking portion (8) can be formed by a gap blocking wall portion (48) that is integral with the auxiliary top plate (40BX) and extends downward from the side edge of the auxiliary top plate (40BX) toward the side edge of the caster mounting plate (5). If the gap closing portion (8) is formed by the gap closing wall portion (48) that forms part of the auxiliary top plate (40BX) as described above, the above effect can be obtained without increasing the number of parts, thereby reducing costs and the labor required for assembly and disassembly.

[0035] As shown in Figures 12 to 16, the gap blocking wall portion (48) can be configured to have an L-shaped cross section, having a vertical wall portion (481) extending downward from the side edge of the auxiliary top plate (40BX) and a lower horizontal wall portion (482) bent from the lower edge of the vertical wall portion (481) to fit along the upper surface of the side edge of the caster mounting plate (5). According to the above embodiment, even if there is a gap between the side edge of the auxiliary top plate (40BX) and the side edge of the caster mounting plate (5) when viewed from above (see Figure 2), the gap between the two can be reliably closed. The gap blocking wall portion 48 has cutouts 483 at both ends thereof to avoid interference with the intermediate frame member 20C and the outer frame member 20B (see FIGS. 13 and 16). The vertical wall portion (481) may be provided vertically downward at a right angle to the auxiliary top plate (40BX), or may be provided to be slightly inclined outward or inward as it extends downward. At least the tip edge portion of the lower surface of the lower horizontal wall portion (482) is abutted against the upper surface of the caster mounting plate (5), and may also be positioned close to the upper surface of the caster mounting plate (5) so that there is a slight gap between it and the upper surface of the caster mounting plate (5). The width (protruding length) of the lower horizontal wall portion 482 may be set appropriately depending on the dimension of the gap. Furthermore, when gap closing walls 48 are provided on both side edges of the auxiliary top plate 40BX as shown in the figure, the widths of the lower horizontal wall portions 482 of the two gap closing walls 48 may be the same, or may be set to different widths depending on the dimension of the gap.

[0036] As a modification of the gap blocking wall 48, as shown in Figure 13(b), drainage holes 484 may be formed in the side surface of the gap blocking wall 48 (in the illustrated case, the vertical wall 481). The presence of such drainage holes 484 can reduce the accumulation of water on the exposed portions of the caster mounting plates 5. The shape and number of the drain holes (484) are not particularly limited as long as they achieve the above-mentioned effects, but may be, for example, a plurality of vertically elongated slits as shown in the figure. The width of the slits is, for example, about 1 to 2 mm.

[0037] Figure 17 shows another modified example of a gap blocking wall portion that is formed integrally with the auxiliary top plate (40BX). The illustrated gap blocking wall portion (48) is composed of a curved wall portion (485) that has an arc-shaped cross section and curves downward from the side edge of the auxiliary top plate (40BX) so that it gradually widens outward. The tip edge of the curved wall portion (485) abuts against or is close to the upper surface of the caster mounting plate (5). 18 shows yet another modified example of a gap blocking wall portion formed integrally with the auxiliary top plate (40BX). The illustrated gap blocking wall portion (48) is composed of an inclined wall portion (486) that extends downward and outward from the side edge of the auxiliary top plate (40BX). The leading edge of the inclined wall portion (486) abuts against or is close to the upper surface of the caster mounting plate (5). However, the cross-sectional shape of the gap blocking wall is not limited to the above-mentioned shapes, and may be other shapes.

[0038] Although not shown in the drawings, in another embodiment other than the above, the gap closing portion can also be configured by a gap closing member provided separately from the auxiliary top plate. The shape of the gap blockage member is not particularly limited, but it can include, for example, an upper horizontal wall portion arranged to fit along the upper or lower surface of the side edge of the auxiliary top plate, and a side wall portion (such as the vertical wall portion (481), curved wall portion (485), or inclined wall portion (486) described above) extending downward from the leading edge of the upper horizontal wall portion toward the side edge of the caster mounting plate. Furthermore, instead of or in addition to the upper horizontal wall portion, a lower horizontal wall portion may be provided that is arranged from the lower edge of the side wall portion to fit along the upper surface of the side edge of the caster mounting plate. The gap blockage member is usually attached to at least one of the side edges of the auxiliary top plate and the caster mounting plate, but it may be used without being attached to both. The gap blockage member can be attached and fixed by fastening means such as screws, or by fitting or engaging means. According to the above aspect, the gap between the side edges of the auxiliary top plate and the caster mounting plate can be blocked by the gap blocking member, but if the gap blocking member is removed, the gap can be left unblocked. In addition, the side wall portion of the gap blocking member may be made movable (swinging, sliding, etc.) so that it can be selectively adapted to block the gap between the side edges of the auxiliary top plate and the caster mounting plate, or to not block the gap. [Industrial Applicability]

[0039] The present invention is suitably used as a cart for carrying and transporting luggage and the like, particularly as a cart having a central top plate that is frequently replaced. [Explanation of symbols]

[0040] (1)(1X): Dolly (2): Frame (20A): Front and rear outer frame members (20B): Left and right outer frame members (20C): Intermediate frame member (21):Vertical wall part (211): Lower flange (22): Upper horizontal wall section (23): Lower horizontal wall (3): Caster (4): Top plate (40A): Center top plate (41):Top wall part (42): Side wall (421): Lower flange (43): Intermediate hanging wall part (431): Lower flange (40B)(40BX): Auxiliary top plate (48): Gap blocking wall (481):Vertical wall (482): Lower horizontal wall (5): Caster mounting plate (6): Connection parts (8): Gap blocking part

Claims

1. A dolly comprising an underframe having outer frame members on the front, rear, left and right sides, a plurality of casters provided on the underframe's underside, and a top plate provided on the underframe to form a loading surface, The underframe further includes two intermediate frame members that are secured in parallel at a predetermined interval to each other at intermediate portions of the length of the front and rear or left and right outer frame members, The top plate has a central top plate disposed and fixed between the two intermediate frame members, The central top plate is provided so as to be detachable independently from the top surface side of the cart.

2. The central top plate has a top wall portion whose upper surface serves as a loading surface, and two side wall portions extending downward from both side edges of the top wall portion, The two intermediate frame members each have a vertical wall portion that can be aligned with the outer surface of each side wall portion of the central top plate, 2. The truck of claim 1, wherein the two side walls of the central top plate are detachably attached to the vertical walls of the two intermediate frame members.

3. A plurality of casters are attached to caster mounting plates that are secured to the underside of the left and right or front and rear outer frame members so as to intersect with the central top plate when viewed from above, The central top plate further has a middle hanging wall portion extending downward from a widthwise middle portion of the top wall portion so as to be parallel to the two side wall portions, 3. The cart according to claim 2, wherein a horizontal lower flange portion is provided at the lower end edge of the intermediate hanging wall portion of the central top plate, the horizontal lower flange portion being brought into contact with the upper surface of the caster mounting plate.

4. 3. The bogie of claim 2, wherein the two intermediate frame members have support projections that protrude from the lower edges of the vertical walls or at intermediate positions in height so as to face each other and support the lower edges of the two side walls of the central top plate, respectively.

5. 5. The bogie of claim 4, wherein the lower edges of the two side walls of the central top plate are provided with horizontal lower flanges that come into contact with the upper surfaces of the support projections of the vertical walls of the two intermediate frame members.

6. 3. A bogie according to claim 2, wherein both end portions of the outer surfaces of the vertical wall portions of the two intermediate frame members are connected to the longitudinal intermediate portions of the front and rear or left and right outer frame members via curved plate-like connecting members that are L-shaped when viewed from above.

7. 7. The bogie of claim 6, wherein each of the two intermediate frame members further has upper and lower horizontal wall portions extending from the upper and lower edges of the vertical wall portion toward the opposite side of the central top plate, and the connecting member has a vertical width approximately equal to the vertical distance between the upper and lower horizontal wall portions.

8. 2. The truck of claim 1, further comprising an auxiliary top plate that is secured across the upper sides of the intermediate frame member and the outer frame member facing it and that is arranged so as not to overlap the central top plate when viewed from above.

9. A plurality of casters are attached to caster mounting plates that are secured to the underside of the left and right or front and rear outer frame members so as to intersect with the central top plate when viewed from above, The top plate further includes an auxiliary top plate that is secured to the upper sides of the intermediate frame member and the outer frame member facing the intermediate frame member and is arranged so as not to overlap with the central top plate when viewed from above, 2. The cart according to claim 1, further comprising a gap closing portion for closing a gap that occurs between the side edges of the auxiliary top plate and the caster mounting plate.

10. 10. The truck of claim 9, wherein the gap closing portion comprises a gap closing wall portion formed integrally with the auxiliary top plate so as to extend downward from the side edge of the auxiliary top plate toward the side edge of the caster mounting plate.

11. The trolley of claim 10, wherein the gap blocking wall portion has a vertical wall portion extending downward from the side edge of the auxiliary top plate and a lower horizontal wall portion bent from the lower edge of the vertical wall portion to fit along the upper surface of the side edge of the caster mounting plate.

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