Transport cart

Abstract

The purpose is to prevent the transport cart from tipping over while keeping it compact. [Solution] The transport trolley 10 of the present invention comprises a trolley body 20 for loading transported goods, casters 31A arranged at at least four corners of the trolley body 20, auxiliary casters 51 located outside the outer edge of the trolley body 20, and a connecting part 60 for connecting the auxiliary casters 51 to the trolley body 20. The connecting part 60 is characterized by allowing the auxiliary casters 51 to transition between a first position located outside the outer edge of the trolley body 20 and a second position closer to the trolley body 20 than the first position.

Description

Technical Field

[0007] , [Figure 1]

[0001] The present invention relates to a transport cart.

Background Art

[0002] In work sites and the like, transport carts are used to transport articles. Casters are attached to the four corners of the lower surface of the cart body.

Prior Art Documents

Patent Documents

[0003] [[ID=​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​This is a perspective view of the transport trolley of the first embodiment, seen from above. [Figure 2] This is a perspective view of the transport trolley of the first embodiment, seen from below. [Figure 3] This is a bottom view of the transport cart according to the first embodiment. [Figure 4] This is a plan view of the transport cart according to the first embodiment. [Figure 5] This is a rear view of the transport trolley according to the first embodiment. [Figure 6] This is a view of the transport cart of the first embodiment from the front. [Figure 7] This is a side view of the transport cart according to the first embodiment. [Figure 8] This is a disassembled perspective view of the grounding unit. [Figure 9] This is a diagram showing the configuration of the grounding unit. [Figure 10] This is a rear view of two stacked transport carts. [Figure 11] This is a cross-sectional view showing two transport carts stacked on top of each other. [Figure 12] This is a bottom view of the transport cart according to the second embodiment. [Figure 13] This is a plan view of the transport cart according to the second embodiment. [Modes for carrying out the invention]

[0008] A transport trolley according to this embodiment will be described with reference to the drawings. [First Embodiment] Figure 1 is a perspective view of the transport trolley 10 according to the first embodiment, viewed from above. Figure 2 is a perspective view of the transport trolley 10 viewed from below. Figure 3 is a bottom view of the transport trolley 10. Figure 4 is a top view of the transport trolley 10. Figure 5 is a view of the transport trolley 10 from the rear. Figure 6 is a view of the transport trolley 10 from the front. Figure 7 is a left side view of the transport trolley 10, which is symmetrical to the right side view. For convenience, in the following diagrams, arrow Fr represents the front, arrow Rr represents the rear, arrow R represents the right side, and arrow L represents the left side. However, the transport cart 10 can travel on the running surface in any direction: forward, backward, left, or right. Also, the center line C is the center of the transport cart 10 in the left-right direction. The transport cart 10 has a symmetrical configuration with respect to the center line C.

[0009] The transport trolley 10 comprises a trolley body 20, a running section 30, a pusher 40, and a ground contact unit 50. First, let me explain the main body of the trolley 20. The trolley body 20 is constructed by connecting multiple frame sections and the like, and is used to load transported goods. In a plan view, the trolley body 20 has a roughly rectangular shape with the front-to-back direction as the longitudinal direction and the left-to-right direction as the transverse direction. The trolley body 20 has a front frame section 21a, a rear frame section 21b, a right frame section 21c, a left frame section 21d, a corner member 22, reinforcing frame sections (reinforcement sections) 25a to 25d, and a guide section 28.

[0010] The front frame section 21a, the rear frame section 21b, the right frame section 21c, and the left frame section 21d constitute the outer shape of the bogie body section 20. Here, the front frame section 21a and the rear frame section 21b correspond to an example of a pair of opposing frame sections. Similarly, the right frame section 21c and the left frame section 21d correspond to an example of a pair of opposing frame sections. The front frame section 21a, the rear frame section 21b, the right frame section 21c, and the left frame section 21d can be made of, for example, a square hollow pipe made of aluminum alloy.

[0011] The corner member 22 is made of an aluminum alloy, for example, formed by extrusion molding. The corner member 22 has an insertion hole 23 that opens upward and a stopper portion 24 that closes downward. The push member 40 can be inserted into the insertion hole 23 of the corner member 22. The lower end of the push member 40 inserted into the insertion hole 23 is supported by the stopper portion 24.

[0012] The front frame portion 21a, the rear frame portion 21b, the right frame portion 21c, and the left frame portion 21d are joined at four corners by the corner members 22 to form a rectangular four-sided frame. Inside the frame, a plurality of reinforcing frame portions 25a, 25b, 25c, and 25d are abutted in the front-rear, left-right directions as reinforcing portions and joined by screws, rivets, welding, etc. to be reinforced. The reinforcing frame portions 25a, 25b, 25c, and 25d can use, for example, angular hollow pipes made of aluminum alloy or plates with uneven cross-sections. Here, by joining 12 short reinforcing frame portions 25c in the left-right direction to two long reinforcing frame portions 25a and 25b in the front-rear direction, a plurality of rectangular spaces 26 divided into three rows in the front-rear direction and five columns in the left-right direction are formed in plan view. Further, in each of the central spaces 26 in the front-rear direction among the two rows of spaces 26 on both the left and right sides, the reinforcing frame portions 25d are joined to the front and rear reinforcing frame portions 25c so as to cross the space 26 in the front-rear direction. Thus, by being partitioned by the reinforcing frame portions 25d, long spaces 27 in the front-rear direction are formed between the right frame portion 21c and the right reinforcing frame portion 25d and between the left frame portion 21d and the left reinforcing frame portion 25d, respectively. The space 27 has an upper opening and a part of the lower side is blocked by a connecting member 61 described later. Note that the shape of the space 27 is not limited to being long in the front-rear direction, and may be long in the left-right direction or square in plan view. Also, the lower side of the space 27 may be open or may be entirely blocked.

[0013] The guide portion 28 guides the sliding of the connecting member 61 of the grounding unit 50. The guide portion 28 has a length shorter than the length of the cart main body portion 20 in the left-right direction. The guide portion 28 is a hollow member having a substantially rectangular cross section, and both ends are open. For the guide portion 28, for example, a square hollow pipe made of an aluminum alloy or the like can be used. Specifically, the guide portion 28 is located between the two front casters 31A and the two rear casters 31B, and more specifically, at the center in the front-rear direction. The guide portion 28 is positioned so as to straddle two reinforcing frame portions 25d that are separated left and right, and is coupled to the lower surfaces of the reinforcing frame portions 25a and 25b by rivets or screws.

[0014] Next, the traveling unit 30 will be described. The traveling unit 30 travels on the traveling surface while supporting the load of the cart main body portion 20 and the transported object. The traveling unit 30 has casters 31A as a plurality of first casters. Specifically, the traveling unit 30 has four casters 31A disposed at the four corners of the cart main body portion 20. The caster 31A is attached to the cart main body portion 20 via an attachment member 32A coupled to each frame portion and each reinforcing frame portion in such a manner as to block the space 26 from below. Further, the caster 31A is rotatable about a turning axis O1 along the vertical direction. Also, the caster 31A is a braked caster that can be braked or the brake can be released according to the operation of the user.

[0015] As shown in FIG. 7, the caster 31A has a wheel 33, a support portion 34, a brake pedal 37, and a turning portion 39. The wheel 33 has a wheel portion with a bearing built therein and a tire portion fitted on the outer periphery of the wheel portion.

[0016] The support portion 34 rotatably supports the wheel 33 via an axle. The support portion 34 has a fork member 35 that supports the wheel 33 and a pedal holding member 36 that holds the brake pedal 37 so as to be swingable. The fork member 35 is formed, for example, by press-forming a steel plate. The fork member 35 is integrally formed from a pair of side walls located on both sides of the wheel 33 and a circular top plate connecting the pair of side walls above the wheel 33. The top plate is held rotatably by a swivel section 39. The pedal holding member 36 is formed, for example, by press-forming a steel plate. The pedal holding member 36 is located on both sides of the wheel 33 and is integrally formed from a pair of side walls fixed to the fork member 35 and a connecting plate that connects the pair of side walls at the top.

[0017] The brake pedal 37 is formed, for example, by press-forming a steel plate. The brake pedal 37 is pivotable up and down relative to the pedal holding member 36. The brake pedal 37 has an operating part 38. The operating part 38 is roughly plate-shaped, and the up and down pivoting of the brake pedal 37 is operated by the user's foot or the like.

[0018] When the brakes are released, the brake pedal 37 is in the raised position. However, when the user operates the brake pedal 37 by pressing the operating part 38 downwards with their foot, the brake pedal 37 swings downwards against the biasing force of the spring. As the brake pedal 37 moves, it firmly presses directly or indirectly against the outer surface of the wheel 33, preventing the wheel 33 from rotating and resulting in a braked state. The brake pedal 37 also functions as a stopper to hold the brake in place. The swivel section 39 rotates the wheel 33, the support section 34, and the brake pedal 37.

[0019] The swivel portions 39 of the casters 31A configured in this way are each attached to the mounting members 32A, and the mounting members 32A with the casters 31A attached are then attached to predetermined positions on the trolley body 20 using rivets or screws, thereby enabling the casters 31A to be mounted on the trolley body 20. In a plan view, the caster 31A is positioned so that the contact point of the wheel 33 and the pivot axis O1 are eccentric. Therefore, the caster 31A rotates around the pivot axis O1 such that the wheel 33 is at the rear relative to the front, which is the direction of travel. In Figure 3, the trajectory T1 of the component of the caster 31A that is furthest from the pivot axis O1 (brake pedal 37) is shown as a dashed line when the caster 31A rotates around the pivot axis O1.

[0020] Next, the push member 40 will be described. The push member 40 is a member for the user to grasp when moving the transport cart 10. The user moves the transport cart 10 by grasping the push member 40 with their hands and pushing or pulling it. The push member 40 is attached to the cart body 20 by inserting its lower end into the insertion hole 23 of the corner member 22. The transport cart 10 has four push members 40, each inserted into the insertion hole 23 of the corner member 22. The four push members 40 are all substantially the same in structure. However, it is not limited to attaching four push members 40; one, two, or three push members 40 may also be attached. The push member 40 can be removed from the cart body 20 by pulling it out of the insertion hole 23 of the corner member 22.

[0021] The push member 40 has a main body member 41 as the main body, a protective member 43, and a reinforcing member 44. The main body member 41 is a rod-shaped or elongated pipe-shaped member. The main body member 41 is made of, for example, an aluminum alloy and is formed by extrusion molding. The main body member 41 is reinforced internally in a cross shape to improve its strength.

[0022] The protective member 43 protects the user's hand from contact with surrounding objects when the user grasps the push member 40. The protective member 43 also serves as an indicator of the maximum load height when loading transported goods. The protective member 43 is fixed to the upper side of the main body member 41 at a predetermined distance from the upper end using bolts, rivets, etc. The part of the push member 40 above the protective member 43 functions as a grip portion for the user to grasp. The protective member 43 is disc-shaped and protrudes outward from the outer circumferential surface of the main body member 41, and has a larger outer diameter than the main body member 41.

[0023] The reinforcing member 44 is fixed to the lower end of the main body member 41, specifically at a position close to the lower end, using bolts, rivets, etc. The reinforcing member 44 reinforces the strength of the main body member 41 and suppresses looseness between the main body member 41 and the insertion hole 23 of the corner member 22 when the main body member 41 is inserted into the insertion hole 23. The reinforcing member 44 is made of, for example, an aluminum alloy and is formed by extrusion molding.

[0024] Next, the grounding unit 50 will be described. The grounding unit 50 functions as an outrigger. The transport trolley 10 of this embodiment has two grounding units 50a and 50b. Specifically, the transport trolley 10 has a grounding unit 50a that is close to the right frame portion 21c and a grounding unit 50b that is close to the left frame portion 21d. Grounding units 50a and 50b are positioned separately in the left-right direction. Furthermore, grounding units 50a and 50b are positioned symmetrically with respect to the center line C. Also, when viewed from the left-right direction (side view), grounding units 50a and 50b are positioned to overlap. Note that grounding units 50a and 50b have the same configuration and will be described simply as grounding unit 50 unless there is a need to distinguish between them.

[0025] The grounding unit 50 of this embodiment has an auxiliary caster 51 as a second caster and a connecting part 60. The auxiliary caster 51 corresponds to an example of the grounding part. The auxiliary casters 51 are located outside the outer edge of the trolley body 20 and are positioned above the running surface (ground contact surface). They prevent the transport trolley 10 from tilting by making contact with the running surface when the transport trolley 10 begins to tilt. In addition, the auxiliary casters 51 are positioned so as not to overlap with the trolley body 20 in a plan view. Specifically, the auxiliary casters 51 of the ground contact unit 50a are located to the right of the right frame section 21c, and the auxiliary casters 51 of the ground contact unit 50b are located to the left of the left frame section 21d.

[0026] Figure 8 is an exploded perspective view of the disassembled grounding unit 50. Figure 9(a) is a view of a part of the grounding unit 50 cut off and viewed from the rear, and Figure 9(b) is a bottom view of the grounding unit 50 shown in Figure 9(a). First, let me explain the auxiliary caster 51. The auxiliary caster 51 is capable of swiveling around a pivot axis O2 that runs vertically. The auxiliary caster 51 is a different type of caster from the caster 31A described above. Specifically, the auxiliary caster 51 is a brakeless caster that cannot be braked.

[0027] As shown in Figure 8, the auxiliary caster 51 has a wheel 53, a support part 54, and a swivel part 59. The outer diameter of wheel 53 is smaller than the outer diameter of wheel 33 of caster 31A. Wheel 53 has a wheel portion with a bearing built inside and a tire portion fitted around the outer circumference of the wheel portion.

[0028] The support portion 54 rotatably supports the wheel 53. The support portion 54 is formed, for example, by press-forming a steel plate. The support portion 54 is integrally formed from a pair of side walls located on both sides of the wheel 53 and a circular top plate connecting the pair of side walls above the wheel 53. The top plate is held rotatably by a swivel portion 59. The swivel section 59 rotates the wheel 53 and the support section 54 around the swivel axis O2.

[0029] The auxiliary caster 51 is positioned so that, in a plan view, the contact point of the wheel 53 and the pivot axis O2 are eccentric. Therefore, when the auxiliary caster 51 is in contact with the running surface, it pivots around the pivot axis O2 such that the wheel 53 is at the rear relative to the front, which is the direction of travel.

[0030] Next, the connecting portion 60 will be described. The connecting portion 60 connects the auxiliary caster 51 to the bogie body 20 such that the auxiliary caster 51 is positioned outside the outer edge of the bogie body 20. The connecting portion 60 in this embodiment can slide relative to the bogie body 20. By sliding the connecting portion 60 relative to the bogie body 20, the auxiliary caster 51 can be moved between a first position in a plan view where it does not overlap with the bogie body 20 and a second position where it overlaps with the bogie body 20.

[0031] As shown in Figure 8, the connecting portion 60 includes a connecting member 61, a mounting member 63, and a protective member 64. The connecting member 61 connects the auxiliary caster 51 to the trolley body 20. The connecting member 61 is elongated, and its length is approximately less than half the length of the trolley body 20 in the left-right direction. The connecting member 61 is a hollow member with a roughly rectangular cross-section, and both ends are open. For example, the connecting member 61 can be made of a square hollow pipe made of aluminum alloy. The auxiliary caster 51 is attached to one end of the connecting member 61 in the longitudinal direction via a mounting member 63. The other end of the connecting member 61 in the longitudinal direction is fitted into the guide portion 28, and the connecting member 61 is slidable along the longitudinal direction of the guide portion 28. In this embodiment, the connecting member 61 of the grounding unit 50a and the connecting member 61 of the grounding unit 50b are fitted into the same guide portion 28 from opposite sides. In addition, a plurality of engagement holes 62a and 62b are formed on the lower side wall of the connecting member 61 at intervals in the left-right direction.

[0032] The mounting member 63 attaches the auxiliary caster 51 to the connecting member 61. The mounting member 63 is a member with a roughly U-shaped cross-section. The mounting member 63 is formed, for example, by bending a steel plate. The mounting member 63 is integrally formed from a pair of side walls and a connecting wall formed by connecting the pair of side walls at their lower ends. The connecting member 61 is sandwiched from the front and back by the pair of side walls of the mounting member 63 and fixed with rivets, screws, etc., thereby attaching the mounting member 63. The auxiliary caster 51 is attached to the mounting member 63 by screwing a bolt that protrudes upward from the swivel part 59 into a nut fixed to the connecting wall of the mounting member 63.

[0033] The protective member 64 prevents the connecting member 61 from being damaged by contact with an obstacle. The protective member 64 is a substantially plate-shaped member. The protective member 64 is made of, for example, synthetic resin. The protective member 64 is attached to the connecting member 61 by fitting into an opening at one end of the connecting member 61. When the protective member 64 is attached to the connecting member 61, the end of the connecting member 61 and the end of the mounting member 63 are covered from the outside by the protective member 64. Therefore, as shown in Figure 7, in a side view, the end of the connecting member 61 and the end of the mounting member 63 are hidden by the protective member 64 and are not visible.

[0034] Furthermore, the trolley body 20 of this embodiment has a stopper portion 80 that stops the sliding of the connecting member 61 so that the connecting member 61 cannot slide freely when the connecting member 61 is guided and slid by the guide portion 28. In this embodiment, a stopper portion 80 is attached to each of the grounding units 50a and 50b so that the sliding of each connecting member 61 of the grounding units 50a and 50b can be stopped. Specifically, two stopper portions 80 corresponding to the grounding unit 50a and the grounding unit 50b are attached to the guide portion 28.

[0035] As shown in Figure 8, the stopper portion 80 includes a housing 81, an engaging member 82, a biasing member 84, and a shaft member 85. The housing 81 pivotably supports the engaging member 82. The housing 81 is a member with a roughly U-shaped cross-section. The housing 81 is formed, for example, by bending a steel plate. The housing 81 is integrally formed from a pair of side walls and a connecting wall that connects the pair of side walls at their lower ends. The guide portion 28 is attached to the housing 81 by being sandwiched from the front and rear by the pair of side walls of the housing 81 and fixed with rivets, screws, etc.

[0036] The engaging member 82 advances into the guide portion 28 and engages with the connecting member 61, thereby stopping the sliding of the connecting member 61. It then retracts from the guide portion 28, releasing the engagement with the connecting member 61 and releasing the stopping of the sliding of the connecting member 61. The engaging member 82 is a roughly block-shaped member that is long in the left-right direction. The engaging member 82 is formed, for example, by bending a steel plate. The engaging member 82 is pivotable around a shaft member 85 supported by the housing 81, and is biased upward by a biasing member 84 so that the end opposite to the side where the shaft member 85 is supported always advances into the guide portion 28 through a hole 29 formed in the lower wall of the guide portion 28. When the engaging member 82 engages with one of the engagement holes 62a, 62b of the connecting member 61 that slides within the guide portion 28, the connecting member 61 is prevented from sliding freely along the guide portion 28.

[0037] Furthermore, the engaging member 82 has a knob 83 for the user to retract the engaging member 82 from within the guide portion 28. The knob 83 corresponds to an example of a release portion that releases the stopping of the sliding of the connecting member 61. When the user pushes the knob 83 downward against the biasing force of the biasing member 84, the engaging member 82 swings and retracts from the guide portion 28. As the engaging member 82 retracts, the engagement with the engaging holes 62a and 62b of the connecting member 61 is released, allowing the connecting member 61 to slide freely along the guide portion 28 while the knob 83 is being pushed down.

[0038] Since the amount by which the connecting member 61 protrudes from the guide portion 28 differs depending on which of the engagement holes 62a and 62b of the connecting member 61 the engaging member 82 engages with, the user can independently adjust the amount by which the connecting member 61 protrudes from the guide portion 28 for each of the grounding units 50a and 50b.

[0039] When the engaging member 82 is engaged with the engaging hole 62a, the amount by which the connecting member 61 protrudes from the guide portion 28 is at its largest. This state corresponds to the first position where the auxiliary caster 51 attached to the connecting member 61 is located outside the outer edge of the bogie body 20. Note that the connecting member 61 is configured so that it does not protrude further from the guide portion 28 than the first position by having a contact portion (not shown) of the connecting member 61 contact a contacted portion (not shown) of the guide portion 28. Here, the auxiliary caster 51 shown by the solid line in Figures 1 to 9 is shown in the first position. Also, the wheel 53 of the auxiliary caster 51 shown by the solid line in Figures 1 to 9 is shown facing in the front-rear direction. In Figure 3, the trajectory T2 of the component of the auxiliary caster 51 that is furthest from the pivot axis O2 (the rear end of the wheel 53) when it is swung around the pivot axis O2 in the first position is shown by a dashed line.

[0040] Furthermore, as shown in Figure 3, in the first position, the auxiliary caster 51 with the wheel 53 facing forward and backward is located outside the outer edge of the bogie body 20. That is, in the first position, in a plan view or bottom view, the auxiliary caster 51 with the wheel 53 facing forward and backward does not overlap with the outer region of the bogie body 20. Here, the outer region of the bogie body 20 refers to the region inside the outer edge of the bogie body 20 in a plan view or bottom view. Furthermore, in the first position, the pivot axis O2 of the auxiliary caster 51 is located outside the outer edge of the bogie body 20. In other words, in the first position, in a plan view or a bottom view, the pivot axis O2 of the auxiliary caster 51 does not overlap with the outer shape area of ​​the bogie body 20.

[0041] On the other hand, in the first position, in a plan view or bottom view, the trajectory T2 of the auxiliary caster 51 partially overlaps with the outer shape area of ​​the trolley body 20. In this way, by having a part of the trajectory T2 of the auxiliary caster 51 overlap with the outer shape area of ​​the trolley body 20, the amount by which the auxiliary caster 51 protrudes outward from the outer edge of the trolley body 20 can be suppressed. However, in the first position, the trajectory T2 of the auxiliary caster 51 may not overlap with the outer shape area of ​​the trolley body 20 in a plan view or bottom view.

[0042] By positioning the auxiliary casters 51 in this first position, even if the transport trolley 10 attempts to tilt, the wheels 53 of the auxiliary casters 51, which are located outside the outer edge of the trolley body 20, will make contact with the running surface, thereby preventing the transport trolley 10 from tilting.

[0043] Furthermore, when the engaging member 82 is engaged with the engaging hole 62b, the connecting member 61 enters the guide portion 28, resulting in the smallest amount of the connecting member 61 protruding from the guide portion 28. This state corresponds to the case where the auxiliary caster 51 attached to the connecting member 61 is in a second position, which is closer to the bogie body 20 than the first position. Here, the auxiliary caster 51 shown by the dashed-dot lines in Figures 3 to 6 and Figure 9 is shown in the second position. Also, the wheel 53 of the auxiliary caster 51 shown by the dashed-dot lines in Figures 3 to 6 and Figure 9 is shown facing in the front-rear direction. In Figure 3, the trajectory T2' of the component of the auxiliary caster 51 furthest from the pivot axis O2 (the rear end of the wheel 53) when it rotates around the pivot axis O2 in the second position is shown by a dashed-dot line.

[0044] As shown in Figure 3, in the second position, the auxiliary caster 51 with the wheel 53 facing forward and backward is located inside the outer edge of the bogie body 20. That is, in the second position, in a plan view or bottom view, the auxiliary caster 51 with the wheel 53 facing forward and backward overlaps with the outer area of ​​the bogie body 20. Furthermore, in the second position, the pivot axis O2 of the auxiliary caster 51 is located inside the outer edge of the bogie body 20. That is, in the second position, in a plan view or a bottom view, the pivot axis O2 of the auxiliary caster 51 overlaps with the outer shape area of ​​the bogie body 20. Furthermore, in the second position, in a plan view or bottom view, the trajectory T2' of the auxiliary caster 51 overlaps with the outer shape area of ​​the bogie body 20. Also, in the second position, in a plan view or bottom view, the trajectory T2' of the auxiliary caster 51 of the grounding unit 50a overlaps with the right frame portion 21c and the right reinforcing frame portion 25d of the bogie body 20, and the trajectory T2' of the auxiliary caster 51 of the grounding unit 50b overlaps with the left frame portion 21d and the left reinforcing frame portion 25d of the bogie body 20.

[0045] By positioning the auxiliary casters 51 in this second position, it is possible to prevent the auxiliary casters 51 from colliding with walls or other objects in narrow passages, even when the transport cart 10 is traveling through such passages.

[0046] Figure 10 is a rear view of two transport carts 10 stacked together, with the auxiliary casters 51 positioned in the second position. Multiple transport carts 10 may be stacked when storing them without using them or when transporting them to and from the work site. In this case, the casters 31A of the upper transport cart 10 are placed on the mounting members 32A of the lower transport cart 10, thereby reducing the overall height of the stacked transport carts 10 by the height of the space 26 above the mounting members 32A.

[0047] On the other hand, when the transport carts 10 are stacked with the auxiliary casters 51 in the first position, the auxiliary casters 51 protrude significantly to the left and right, causing the stacked transport carts 10 to be bulky in the left and right directions. In this embodiment, as shown in Figure 10, by stacking the transport carts 10 with the auxiliary casters 51 in the second position, the protrusion of the auxiliary casters 51 in the left and right directions can be suppressed, and the overall height of the transport carts 10 can also be reduced.

[0048] Here, as shown in Figure 3, in the second position, the auxiliary caster 51 with the wheel 53 facing forward and backward does not overlap with any of the right frame section 21c, the left frame section 21d, or the reinforcing frame sections 25a, 25b, 25c, or 25d. Specifically, in the second position, the auxiliary caster 51 of the ground contact unit 50a is located between the right frame section 21c and the right reinforcing frame section 25d, and the auxiliary caster 51 of the ground contact unit 50b is located between the left frame section 21d and the left reinforcing frame section 25d. In other words, in the second position, the auxiliary caster 51 with the wheel 53 facing forward and backward overlaps with the space 27 of the bogie body section 20 in a plan view or a bottom view.

[0049] Therefore, when stacking identical transport carts 10 with the auxiliary casters 51 positioned in the second position in the vertical direction, the wheels 53 of the auxiliary casters 51 of the upper transport cart 10 fit into the space 27 of the lower transport cart 10, thus reducing the overall height of the stacked transport carts 10.

[0050] Figure 11 is a cross-sectional view showing two transport carts 10 stacked on top of each other, with the auxiliary casters 51 positioned in the second position. As shown in Figure 11, the wheels 53 of the auxiliary casters 51 of the upper transport cart 10 are positioned within the space 27 formed in the cart body 20 of the lower transport cart 10. Here, the lower end of the wheels 53 of the auxiliary casters 51 of the upper transport cart 10 is not in contact with the lower transport cart 10 and is floating. Therefore, even when multiple transport carts 10 are stacked, the load on the wheels 53 of the auxiliary casters 51 can be suppressed.

[0051] On the other hand, because the wheels 53 of the auxiliary casters 51 of the upper transport trolley 10 are floating relative to the lower transport trolley 10, vibrations during transport cause the wheels 53 to attempt to rotate around the pivot axis O2 within the space 27 formed in the trolley body 20 of the lower transport trolley 10. However, in the second position, in a plan view or bottom view, the trajectory T2' of the auxiliary casters 51 of the grounding unit 50a overlaps with the right frame portion 21c and the right reinforcing frame portion 25d of the trolley body 20, and the trajectory T2' of the auxiliary casters 51 of the grounding unit 50b overlaps with the left frame portion 21d and the left reinforcing frame portion 25d of the trolley body 20. Therefore, even if the wheel 53 attempts to rotate around the pivot axis O2, the wheel 53 will be contained within the space 27 of the trolley body 20 of the lower transport trolley 10 and will come into contact with the right frame portion 21c, the left frame portion 21d, or the reinforcing frame portion 25d, thereby suppressing the rotation of the wheel 53.

[0052] In this way, the auxiliary casters 51 of the upper transport cart 10 fit into the space 27 of the cart body 20 of the lower transport cart 10, which helps to prevent the stacked transport carts 10 from becoming bulky in the height direction. As a result, the stacked transport carts 10 can be stored and moved in and out compactly. Although this explanation describes the case of stacking two transport carts 10, the same method of preventing the stacked transport carts 10 from becoming bulky in the height direction can be used when stacking three or more transport carts 10.

[0053] As described above, the transport trolley 10 of this embodiment comprises a trolley body 20 for loading transported goods, casters 31A positioned at at least four corners of the trolley body 20, auxiliary casters 51 as ground contact points located outside the outer edge of the trolley body 20, and connecting parts 60 for connecting the auxiliary casters 51 to the trolley body 20. The connecting parts 60 move the auxiliary casters 51 between a first position located outside the outer edge of the trolley body 20 and a second position closer to the trolley body 20 than the first position. Therefore, the transport trolley 10 can be prevented from tipping over while remaining compact.

[0054] (Variation 1) The first embodiment of the transport trolley 10 described above has been described in the case where the ground contact portion is an auxiliary caster 51, but it is not limited to this case. The ground contact portion only needs to be able to prevent the transport trolley 10 from tilting, and may be shaped to protrude from the connecting portion 60 toward the running surface, for example. If the ground contact portion is shaped to protrude toward the running surface, the impact with the running surface when it comes into contact with the running surface can be mitigated by making the lower end a curved surface, such as by forming it into a hemisphere.

[0055] (Modification 2) The first embodiment of the transport trolley 10 described above describes a case where the wheels 53 of the auxiliary caster 51 are not in contact with the running surface, but it is not limited to this case. The wheels 53 of the auxiliary caster 51 may be in constant contact with the running surface. Furthermore, the first embodiment described above describes a case where the auxiliary caster 51 can pivot about the pivot axis O2, but it is not limited to this case. The auxiliary caster 51 may not be able to pivot, but may be fixed in a direction in which the wheels 53 can rotate along the front-rear direction.

[0056] (Variation 3) The first embodiment of the transport trolley 10 described above describes a case where the auxiliary caster 51 has one wheel 53, but it is not limited to this case. The auxiliary caster 51 may have two wheels. That is, the auxiliary caster 51 may have two wheels 53 arranged in parallel between a pair of side walls of the support portion 54.

[0057] (Modification 4) The first embodiment of the transport trolley 10 described above describes a case in which the auxiliary caster 51 can transition stepwise between a first position and a second position, but it is not limited to this case. The auxiliary caster 51 may be configured to transition to any position desired by the user between the first position and the second position, or it may be fixed in either the first position or the second position without being able to transition. Here, fixing the auxiliary caster 51 in either the first position or the second position without being able to transition can be achieved by omitting the guide portion 28 and directly or indirectly connecting the connecting member 61 to the trolley body portion 20. Furthermore, the connecting portion 60 may be configured to allow the auxiliary caster 51 to transition to a third position different from the first and second positions.

[0058] (Variation 5) The first embodiment of the transport trolley 10 described above describes a case where the stopper portion 80 is attached to the lower side of the guide portion 28, but it is not limited to this case. The stopper portion 80 may be attached to the front, rear, or upper side of the guide portion 28, or it may be attached to the connecting member 61.

[0059] (Experimental variation 6) The first embodiment of the transport trolley 10 described above describes a case in which the connecting member 61 does not protrude further from the guide portion 28 than the first position, but it is not limited to this case. The connecting member 61 may be configured to protrude further from the guide portion 28 than the first position so that it can be detached from the guide portion 28. By configuring it in this way, the grounding unit 50 can be attached to and detached from the trolley body 20.

[0060] (Example 7) In the first embodiment of the transport trolley 10 described above, a mounting section may be attached to the upper side of one of the multiple spaces 26 that is not blocked by the mounting member 32A. The mounting section is a flat plate (for example, a metal plate) for placing the transported object on. The mounting section can be connected to each frame section or each reinforcing frame section by rivets or screws. It is preferable that the mounting section is shaped so as not to cover the upper side of the space 27.

[0061] (Variation 8) In the first embodiment described above, when the auxiliary caster 51 is in the second position, a portion of the trajectory T2' of the auxiliary caster 51 may not overlap with the outer shape area of ​​the trolley body 20 in a plan view or a bottom view. That is, a portion of the trajectory T2' of the auxiliary caster 51 may extend beyond the outer edge of the trolley body 20. Also, in the second position, when the trajectory T2' of the auxiliary caster 51 of the grounding unit 50a may not overlap with at least one of the right frame portion 21c and the right reinforcing frame portion 25d of the trolley body 20 in a plan view or a bottom view. Also, in the second position, when the trajectory T2' of the auxiliary caster 51 of the grounding unit 50b may not overlap with at least one of the left frame portion 21d and the left reinforcing frame portion 25d of the trolley body 20 in a plan view or a bottom view. Furthermore, the embodiments and modifications described later may be applied to this embodiment in appropriate combinations or modifications.

[0062] [Second Embodiment] Figure 12 is a bottom view of the transport trolley 110 according to the second embodiment. Figure 13 is a top view of the transport trolley 110. In the following description, we will focus on configurations that differ from the first embodiment, and similar configurations will be denoted by the same reference numerals, and their descriptions will be omitted as appropriate. The transport trolley 110 comprises a trolley body 120, a running section 130, and a ground contact unit 50.

[0063] The bogie body 120 differs from the first embodiment in the position of the reinforcing frame 25d and the position of the space 27. Specifically, in the bogie body 120 of this embodiment, four reinforcing frame 25d are joined so as to cross the front and rear spaces 26 of the central space 26 in the front-to-back direction, out of the two rows of spaces 26 on both the left and right sides. In this way, by being divided by the four reinforcing frame 25d, a total of four spaces 27 are formed, two on the right side and two on the left side.

[0064] Furthermore, in the bogie body 120 of this embodiment, two guide sections 28 are arranged on the front and rear sides. The front guide section 28 is positioned to straddle two front reinforcing frame sections 25d that are spaced apart to the left and right, and the rear guide section 28 is positioned to straddle two rear reinforcing frame sections 25d that are spaced apart to the left and right.

[0065] The running section 130 has four casters 31A and two casters 31B. The casters 31B are positioned in the center in the front-rear direction and spaced apart to the left and right. The casters 31B are attached to the bogie body 120 via mounting members 32B connected to each frame section and each reinforcing claim section in such a manner that they close the space 26 from below. The casters 31B are rotatable about a pivot axis O1 along the vertical direction. Furthermore, the casters 31B are casters without brakes. A caster without a brake is a configuration in which the brake function is omitted from the casters 31A. Specifically, the casters 31B are a configuration in which the pedal holding member 36 and the brake pedal 37 are omitted from the casters 31A. Furthermore, when stacking the transport trolleys 110, the casters 31A and 31B of the upper transport trolley 110 are placed on the mounting members 32A and 32B of the lower transport trolley 110, respectively. This reduces the overall height of the stacked transport trolleys 110 by the height of the space 26 above the mounting members 32A and 32B.

[0066] Here, if we consider the grounding units 50a and 50b as one set, the transport trolley 110 of this embodiment has two sets of grounding units 50a and 50b. Specifically, the first set of grounding units 50a and 50b are positioned between the two front casters 31A and the two central casters 31B, corresponding to the front guide section 28, and the second set of grounding units 50a and 50b are positioned between the two rear casters 31A and the two central casters 31B, corresponding to the rear guide section 28. Therefore, the transport trolley 110 has two grounding units 50a close to the right frame section 21c and two grounding units 50b close to the left frame section 21d. Note that the grounding units 50a and 50b have the same configuration as in the first embodiment, and are denoted by the same reference numerals, so their description is omitted.

[0067] Therefore, in this embodiment as well, the connecting portion 60 moves the auxiliary caster 51 between a first position located outside the outer edge of the trolley body 120 and a second position closer to the trolley body 120 than the first position. Thus, it is possible to prevent the transport trolley 110 from tipping over while keeping it from being bulky. In addition, in this embodiment as well, the auxiliary caster 51 of the upper transport trolley 110 fits into the space 27 of the trolley body 120 of the lower transport trolley 110, thereby suppressing the bulkiness of the stacked transport trolleys 110 in the height direction.

[0068] Furthermore, in this embodiment, the transport trolley 110 has two ground contact units 50a located close to the right frame section 21c and two ground contact units 50b located close to the left frame section 21d, thereby further preventing tilting.

[0069] Although the present invention has been described above with reference to the embodiments described above, the present invention is not limited to the embodiments described above, and modifications can be made within the scope of the present invention by combining each embodiment and each variation. [Explanation of Symbols]

[0070] 10, 110: Transport cart 20, 120: Cart body 21a: Front frame 21b: Rear frame 21c: Right frame 21d: Left frame 25a~25d: Reinforcement frame 27: Space 31A, 31B: Casters 33: Wheels 50 (50a, 50b): Ground contact unit 51: Auxiliary caster (ground contact part) 53: Wheels 60: Connecting part 80: Stopper part 83: Knob part (release part)

Claims

1. The main body of the trolley on which the transported goods are loaded, Casters are positioned at least four corners of the main body of the trolley, A ground contact portion located outside the outer edge of the bogie body, The ground contact portion is connected to the main body of the trolley, The aforementioned connecting portion is A transport trolley characterized by transitioning the ground contact portion between a first position located outside the outer edge of the trolley body and a second position closer to the trolley body than the first position.

2. The trolley body has a pair of opposing frame parts that constitute its outer shape, The transport trolley according to claim 1, characterized in that the second position is a position in which the ground contact portion overlaps with the outer shape area of ​​the trolley body when viewed from below, and does not overlap with the frame portion.

3. The trolley body comprises a frame on all four sides and reinforcing parts arranged within the frame. The transport trolley according to claim 1, characterized in that the second position is a position in which the ground contact portion overlaps with the outer shape area of ​​the trolley body when viewed from below, and does not overlap with either the frame or the reinforcing portion.

4. The trolley body has a space that is open at the top, The transport trolley according to claim 1, characterized in that the second position is a position in which the ground contact portion overlaps with the space when viewed from below.

5. If we consider the aforementioned caster to be the first caster, The transport trolley according to claim 1 or 2, characterized in that the ground contact portion is a second caster different from the first caster.

6. The transport trolley according to claim 5, characterized in that the outer diameter of the wheel of the second caster is smaller than the outer diameter of the wheel of the first caster.

7. The transport trolley according to claim 5, characterized in that the second caster is capable of pivoting about a pivot axis along the vertical direction.

8. The transport trolley according to claim 1 or 2, characterized in that the contact portion is positioned away from the ground surface and makes contact with the ground surface when the transport trolley tilts.

9. The bogie body or the connecting part is The transport trolley according to claim 1 or 2, characterized in that it has a stopper portion for stopping the connecting portion at the first position and the second position.

10. The stopper portion is, The transport trolley according to claim 9, characterized in that it has a release part for releasing the stopped state of the connecting part.

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