JP7464251B2 - Self-propelled transport device - Google Patents

Description

The present invention relates to a self-propelled transport device that moves by itself while towing and transporting various devices and materials under automatic control.

Patent Document 1 discloses a portal lifter used for loading and unloading luggage (heavy objects) and for installing machinery, in which each of the left and right carriages has a telescopic boom that can be extended up and down and a beam is erected between the upper ends of the telescopic booms, and in which two jack devices (four in total) are provided at intervals on the front and rear of each carriage.

Other conventional conveying devices for conveying various materials and heavy objects include a platform consisting of four corner posts that can be raised and lowered, a top frame that is provided at the tops of these posts and connects them together, a suspension beam that is attached to the top frame and is used to suspend the items to be conveyed, a lifting device that simultaneously raises and lowers the posts, support devices that are provided at the bottoms of the posts and movably support the platform, and a movable support platform that is detachably connected to the platform and supports the load of the items to be conveyed (Patent Document 2).

A crematorium transport vehicle that lifts and transports a coffin at a crematorium has also been disclosed (Patent Document 3). This vehicle lifts and transports the coffin using a lift rod in the front-rear direction that serves as a loading section provided on the vehicle body.

JP 2007-76789 A Patent Publication No. 06-088755 JP 2018-025379 A

However, all of the above conventional methods either suspend the materials to be transported (Patent Document 1) or lift them up using a lift that penetrates from below (Patent Document 2), and when the materials are heavy, there are limitations on the weight that can be transported. Also, when the materials have a high center of gravity, the balance cannot be maintained and stable transportation may not be possible. When attempting to solve these problems by constructing a support with high rigidity and strength, the volume and weight become bulky, and there is a problem that it cannot be constructed compactly and lightweight. In addition, a relatively large vehicle structure is required to make the suspension support structure or the lift support structure by penetrating movable. This causes problems such as limitations on the direction of movement and poor maneuverability.

The objective of this invention is to provide a self-propelled transport device that is not subject to restrictions on the transport load even when the materials are heavy, that maintains balance and can transport stably even when the materials have a high center of gravity, and that is relatively maneuverable with few restrictions on the direction of movement.

(1) The self-propelled transport device according to the present invention is
A transport device comprising a self-supporting structure in which a pair of running walls are arranged on the left and right sides to sandwich a transport cart from both sides and a connecting body is arranged above the transport cart in the left and right direction,
The self-supporting structure includes:
A pair or pairs of left and right running walls arranged so as to be able to run on both sides of the transport cart,
A connecting body is fixed between each of the running walls so as to extend over the top of the transport cart.
Each running wall is
A towing arm provided on the inner surface side for towing the side of the transport cart;
A self-propelled wheel provided at the bottom,
A drive device for the self-propelled wheel is provided inside the self-propelled wheel or on a lower side of the wall surface,
The transport cart is transported by self-propelling using a drive unit and self-propelled wheels while being pulled and fixed from both sides by the towing arms on the left and right running walls without being suspended, lifted or supported from below.

The structure allows the transport cart to be towed from the side without being suspended, lifted, or supported from below, i.e., without getting under the cart for support. Therefore, even if the transport cart is loaded with heavy objects or has a high center of gravity, the transport cart can be towed stably from both sides. Also, since the transport cart is not pulled in one direction from one end, but rather pulled and/or pushed from both sides, it has a high degree of freedom of movement regardless of the load condition, making it a maneuverable transport device.

(2) The self-propelled transport device according to the present invention is characterized in that the running wall has multiple self-propelled wheels in the front-rear direction, and in plan view, all towing positions by the towing arm are included within the central 1/3 range (center range of the wheelbase) of the distance between the axles of the self-propelled wheels at the front and rear ends of the running wall. This defines the front-rear positional relationship between the front and rear sections of the wheels provided at the bottom of the running wall and the towing arm for the transport cart provided on the inside part of the running wall. For example, as shown in FIG. 8 described later, when the self-propelled wheel wheelbase 4B, which is the distance between the front and rear axles of the front and rear self-propelled wheels 4 among the multiple self-propelled wheels 4 provided in the front-rear direction of the base body 10 of each running wall 1, is defined, and the wheelbase center 4BC, which is the center of this self-propelled wheel wheelbase 4B, is defined, all towing positions by the towing arm 3 (front-rear storage positions of the connecting pin 7P) are included within the range (center range 4BC of the wheelbase) of 1/3 of the length of the self-propelled wheel wheelbase 4B centered on the wheelbase center 4BC.

Particularly preferably, the self-propelled transport device according to the present invention has a running wall with multiple self-propelled wheels in the front-rear direction, as shown in FIG. 8 of the embodiment, and all towing positions by the towing arms are provided at the center position (wheelbase center) of the axle distance of the self-propelled wheels at the front and rear ends of the running wall in a plan view. By connecting the transport cart T with a pin at the wheelbase center of the self-propelled wheels or at a position within a center range of one-third of the wheelbase, in a lateral towing method in which the left and right sides of the transport cart T are towed laterally, the most stable towing and transport can be achieved regardless of the position of the center of gravity of the cart T.

(3) Alternatively, the self-propelled transport device according to the present invention is characterized in that it tows a rectangular transport cart in plan view, and that in plan view, the centroid (diagonal center) of the transport cart and the diagonal intersection point diagonally connecting the vertical axles at the front and rear ends of the left and right running walls overlap within the central 1/3 of the wheelbase distance between the front and rear ends of the left and right running walls. More preferably, the left and right towing arms are arranged in a pair or multiple pairs at diagonal positions in plan view, that is, at positions on a diagonal line in the short direction passing through the center of gravity. This specifies the positional relationship in the front and rear direction between the front and rear sections of the wheels provided at the bottom of the running walls and the centroid position of the transport cart towed by the towing arms provided on the running walls. For example, as shown in FIG. 8 described later, among the multiple self-propelled wheels 4 provided in the front-rear direction of the base body 10 of each running wall 1, when the self-propelled wheel wheel base 4B, which is the distance between the front and rear axles of the front end self-propelled wheel 4 and the rear end self-propelled wheel 4, is defined, and the wheel base center 4BC, which is the center of this self-propelled wheel wheel base 4B, is defined, all towing positions (front-rear storage positions of the connecting pin 7P) by the towing arm 3 are included within a range (wheel base center range 4BC) of 1/3 of the length of the self-propelled wheel wheel base 4B centered on the wheel base center 4BC. For example, as shown in FIG. 8 described later,

(4) The towing arm has an opening/closing frame body that can open and close the space within the frame by opening and closing operations,
In addition, a fixed towing jig having a connecting pin is fixed facing outward at each side position of the transport cart,
The connecting pin of the connecting jig is loosely fitted and connected by the opening and closing frame body of the towing arm.
That is, a towing jig having a connecting pin is fixed to each side of the transport cart, and the towing arm has an openable/closable frame body that connects the connecting pin with a loose fit in the space within the frame.
The towing jig fixed to the transport cart is towed and fixed by loosely fitting the connecting pin to the opening and closing frame of the towing arm. The towing jig is provided with a connecting pin connectable to the towing arm, and the connecting pin is fixed so as to face outward from each side position of the transport cart.
The opening and closing frame of the towing arm fixed to the transport cart and the connecting pin of the towing jig are loosely connected to adjust the position or height of the transport cart and the running wall. For example, if there is a step or height difference on the floor surface on the left and right, the left and right towing parts can be loosely connected to adjust the height, preventing the running wheels of the running wall from lifting off the ground.
The towing tool in the embodiment described later has a connecting pin fixed to the transport cart in either the height direction (vertical direction) or the width direction (horizontal direction) as a connecting axis. The opening and closing frame in the embodiment described later has an inner frame space penetrating in the height direction (vertical direction) or the width direction (horizontal direction) with the connecting axis of the connecting pin as the normal direction, and the inner frame space is either in a closed state or in an open frame state by the opening and closing operation.

(5) At least one of the towing tool or the towing arm is characterized in that a guide material is provided between the opposing surfaces of the side of the transporting cart and the inner surface of the running wall, which guides the planar posture of the transporting cart and suppresses excessive directional displacement of the transporting cart relative to the running wall when the transporting cart is towed and fixed by the left and right towing arms.
In the embodiment described later, the towing jig is provided with a vertical connecting pin that can be connected to the towing arm, and a guide mechanism having a disk-shaped guide member that is supported on a shaft so as to be freely rotatable is provided at a position that protrudes outward from the connecting pin in a plan view. The guide member 7G is provided with a part of its free rotating portion protruding to a position that protrudes outward from the connecting shaft position of the connecting pin 7P. Furthermore, it is preferable that a guide bumper 3G that is a trapezoidal plate in a plan view and that the guide member 7G abuts against is provided on the inner surface of the running wall that faces the guide bumper in the towing connection state (FIG. 7).

(6) At least one of the multiple self-propelled wheels in the running wall is a Mecanum wheel that rotates around a fixed horizontal axle and has multiple diagonal barrel-shaped rotating bodies around the outer periphery of the rotating wheel.

By taking the above measures, the present invention provides a self-propelled transport device that is less likely to impose restrictions on the transport load of materials, maintains balance even when the center of gravity is high, can transport materials stably, and is less likely to be restricted in the direction of movement, making it relatively maneuverable.

FIG. 1 is a top perspective view of a self-propelled transport device according to a first embodiment. FIG. 1 is a front view of a self-propelled transport device according to a first embodiment. FIG. 2 is a right side view of the self-propelled transport device according to the first embodiment. 1 is a plan view of a self-propelled transport device and a transport cart according to a first embodiment, and an enlarged view of a portion α-α thereof. FIG. 1 is a plan view of a self-propelled conveying set including a self-propelled conveying device according to a first embodiment, and an enlarged view of a β-β portion thereof; 1 is a top perspective view of a self-propelled conveying set including a self-propelled conveying device according to a first embodiment; FIG. 2 is a front top perspective view showing a towing and fixing part of the self-propelled conveying set including the self-propelled conveying device according to the first embodiment; FIG. 2 is an explanatory plan view showing the planar positional relationship of the self-propelled transport device and the transport cart according to the first embodiment in a towed and fixed state. FIG. 2A is a perspective view of the towing jig according to the first embodiment. FIG. 4B is a plan view of the towing jig according to the first embodiment. 13A is a perspective view of a towing jig according to a second embodiment, and FIG. 13B is a partially enlarged view of a tip portion of the towing jig. FIG. 11 is a plan view of the towing jig according to the second embodiment in a fixed state. 13A and 13B are a perspective view and a plan view showing a state in which a towing jig according to a third embodiment is fixed to one transport cart. FIG. 13 is a front view showing a state in which the towing jig according to the third embodiment is fixed to another transport cart.

The following describes a self-propelled transport device according to a first embodiment of the present invention, a self-propelled transport set consisting of a set of this self-propelled transport device and a transport cart used with the self-propelled transport device, and a towing tool fixed to the transport cart. However, the letters, numbers, and character strings consisting of a combination of numbers and letters written following each term are reference symbols that show examples of embodiments together with the drawings, and the reference symbols are not included in the component names, and do not limit the concept, form, or function.

First Embodiment
A self-propelled transport device 100 according to a first embodiment of the present invention will be described below with reference to Figs. 1 to 8. Of these, Figs. 5 to 8 show a self-propelled transport set consisting of the self-propelled transport device 100 according to the first embodiment and a transport cart W. Figs. 9 and 10 show a towing jig according to the first embodiment, which is fixed to the transport cart. Figs. 11 and 12 show a towing jig according to a second embodiment, which is fixed to the transport cart.

<Self-propelled transport device 100>
First, the self-propelled transport device 100 will be described. As shown in Fig. 1, the self-propelled transport device is made of a self-supporting structure in which a transport cart is sandwiched between a pair of running walls 1 arranged on the left and right and connected to a connector 2 that spans the top of the transport cart T in the left-right direction. The combination of this self-supporting structure and the transport cart that is towed and fixed by the self-supporting structure is the self-propelled transport set shown in Figs. 4 and 5.

(self-supporting structure)
The self-supporting structure is
A pair or pairs of left and right running walls 1 arranged on both sides so as to be capable of independent running;
The running walls 1 are made up of a box-shaped base body 10 and a frame body connected to the upper part of the base body 10 by vertical frames 11 and horizontal frames 12, and two connecting frames 21 are connected and fixed to span the left and right between the pair of left and right running walls.

The connecting frame 21 is composed of a front connecting frame 21 that horizontally connects the front ends of the horizontal frames 12 at the upper end of the running wall 1, and a rear connecting frame 21 that horizontally connects the rear ends of the horizontal frames 12 at the upper end of the running wall 1.

This self-supporting structure 100 is made up of vertical frames 11 of the left and right running bodies 1 and connecting frames 21 that connect the upper ends of the vertical frames 11 together, forming a gate-shaped frame connection body when viewed from the front. Reinforcing plates 22 that are roughly triangular when viewed from the front and back are fixed to the upper two corners of the gate-shaped shape when viewed from the front, i.e., the connection parts between the upper ends of the vertical frames 11 and the left and right ends of the connecting frames 21 (Figure 1).

The self-supporting structure 100 is made up of the horizontal frames 12 of the left and right running bodies 1 and the front and rear connecting frames 21 that connect the front ends and rear ends of the horizontal frames 12, forming a rectangular frame-shaped connected body in a plan view. Small reinforcing plates 122 that are roughly triangular in plan view are fixed to the four corners of the rectangular frame in a plan view, i.e., the connecting parts between the front and rear ends of the horizontal frames 12 and the left and right ends of the connecting frames 21 (Figure 1). These reinforcing plates and small reinforcing plates connect the four frame connecting parts at the top of the self-supporting structure 100 so that the angle of the three frames cannot be changed, forming a rigid frame structure that can stand on its own and does not easily deform.

(Running wall 1)
The left and right running walls 1 form a vertically long rectangular frame structure in side view, consisting of a box-shaped base body 10 extending in the front-rear direction, and a four-sided rectangular frame structure consisting of vertical frames 11, horizontal frames 12, and a bottom frame connected to the upper part of the base body 10. Small reinforcing plates 122 having a substantially triangular shape in side view are fixed to the inside of the frame at the two upper corners of this frame structure, i.e., the connection parts between the upper ends of the vertical frames 11 and the front and rear ends of the horizontal frames 12 (FIG. 1).

In addition, upper and lower internal frames 13 that connect the front and rear vertical frames 11 horizontally are connected inside the side view frame structure of the running wall 1, and the upper and lower internal frames 13 support and fix the operation panel 16 near the center of the height direction of the vertical frames 11. Small reinforcing plates 132 of approximately triangular shape are fixed to the connection parts between the front and rear ends of the internal frame 13 and the front and rear vertical frames 11 inside the frame and above the upper end or below the lower end of the operation panel 16 in side view (Figure 1).

The operation panel 16 has an operation module installed inside the panel, and an emergency stop button 16B is provided on the door surface on the outside of the panel (Figure 1).

(Battery 5B)
A box-shaped battery 5B is disposed near the center in the front-to-rear direction on the top of the box-shaped base body 10, and driving power is supplied from this battery 5B to the driving motor of the running wheels 4 inside the base body 10.

(Adjuster 14)
Of the left and right running walls 1, the running wall on one side (the right side as viewed in FIG. 1) is provided with an adjuster 14 that connects the rectangular frame structure and the base body 10 at its lower part in an angle variable manner, at approximately the center in the front-rear direction of the base body 10. This adjuster 14 is made up of a pair of upper and lower couplers that connect the lower part at the center in the front-rear direction of the lower bottom frame of the rectangular frame consisting of the front and rear vertical frames 11, the upper horizontal frame 12, and the lower bottom frame to the upper part at approximately the center in the front-rear direction of the base body 10 in an angle variable manner (FIG. 3). Even if the running surface is uneven, the adjuster 14 allows the running body 10 on one side to tilt in the front-rear direction relative to the frame structure, making it easy to keep all the running wheels 4 in contact with the ground.

(Suspension 15)
Suspensions 15 are provided at the front and rear ends of the upper portion of the base body 10 on which the adjuster 14 is provided, connecting the bottom frame of the frame structure and the base body 10 from top to bottom. The suspensions 15 absorb shocks that the base body 10 receives from the ground and cushion shocks to the frame structure whose angle has been changed by the adjuster 14.

The self-supporting structure of the self-propelled transport device transports the transport cart by independently propelling it using the drive mechanism and self-propelled wheels while it is towed and fixed from both sides (without being suspended or supported by submerging it) by the towing arms on the left and right running walls.

(Running wall 1)
The left and right running walls are
A towing arm provided on the inner surface side for towing the side of the transport cart;
A self-propelled wheel provided at the bottom,
The self-propelled wheel drive unit is provided inside the self-propelled wheel or on the lower side of the wall, and the wall is made of a wall that can stand on its own by the front and rear self-propelled wheels. As shown in the drawings of the embodiment, the wall may be made of a vertical frame and a front and rear frame, and the wall does not necessarily need to be closed.

(Self-propelled wheels)
Each of the left and right running walls has multiple self-propelled wheels in the front-rear direction. The same number of self-propelled wheels are arranged at the same positions (symmetrical) in the front-rear direction on each of the left and right running walls, and at least one wheel at a common wheel position is a Mecanum wheel that rotates around a fixed axle and has a barrel-shaped rotating body in an oblique direction. A drive motor 5 is housed in the center of the wheel, and the driving force is directly transmitted in a wheel-in motor format.

(Plane position of towing position 3P 1: Relationship between wheelbase center 4C/TC and towing position 3P)
When viewed in a plan view, all towing positions by the towing arms are included within the central 1/3 range (center range of the wheelbase) of the distance between the axles of the self-propelled wheels 4 at the front and rear ends of the running wall 1 (running wall wheelbase 4B).

Moreover, in plan view, all towing positions of the transport cart T by the towing arm 3 are provided at the center position (wheelbase center 4C) of the distance between the axles of the self-propelled wheels at the front and rear ends of the running wall (running wall wheelbase 4B) or at the front and rear positions within the central third range (wheelbase center range 4BC) (Figure 8). The towing positions refer to the front and rear positions of the accommodation recess 3D of the towing arm 3 when accommodating the connecting pin 7P of the towing jig 7 fixed to the side of the transport cart T as in the embodiment. As shown in Figures 4, 5, 7, and 8, the towing arm 3 of the embodiment has accommodation recesses 3D that are approximately semicircular in plan view at the front and rear of the base body 31,

(Plane position of towing position 3P 2: Relationship between the centroid position of the bogie and towing position 3p)
The transport device of the present invention tows a rectangular transport cart in plan view, and is characterized in that the centroid (diagonal center) of the transport cart and the diagonal intersection of all towing positions diagonally connected by the left and right towing arms overlap within the central 1/3 of the wheelbase distance at the front and rear ends in plan view. As the transport cart T, for example, a cage cart formed into a box shape by a cage net, or a cart having a flat frame bottom plate called a 1-ton cart or flat plate cart is used. The towing arms 3 are attached to the left and right sides of the transport cart T at the same positions in the front and rear direction. It is preferable that the towing arms 3 are provided within the central range of the wheelbase of the transport cart and within the central range of the wheelbase of the running wall 1.

(Towing arm)
The towing arm 3 is towed and fixed to a fixed towing jig 6, the tip of which is fixed to each side position of the transport cart and protrudes outward. The towing arm is composed of a horizontal plate-like base body 30 having a storage recess 3D, which is a recess of the storage space, on the front and rear sides of a rectangle in a plan view, and a movable opening and closing arm 31 provided near the front and rear storage recess 3D of the base body 30. The opening and closing arm 31 is incorporated so as to close the outside of the storage recess 3D in the released state, and in this state, is elastically biased outward. When an external force is applied from the outside of the front and rear positions of the base body 30 to the storage recess 3D side (the center side of the base body 30), the towing arm 31 opens inward to open the storage recess 3D, and the connecting pin 7P fixed vertically to the tip of the towing jig 7 is accommodated in this storage recess 3D, thereby loosely fitting and connecting the connecting pin 7P. When the connecting pin abuts against the front and rear edges of the base body, the opening/closing arm moves toward the recessed side, i.e., inward, of the storage space, thereby storing the connecting pin within the storage space. The opening/closing arm then automatically returns to its original position at the front and rear edges of the arm base body, thereby loosely inserting and storing the connecting pin within the storage space (top diagram in Figure 4 and top diagram in Figure 5).

In the embodiment, the base body has recesses for the storage spaces on the front and rear sides, and has opening and closing arms that cover the recesses corresponding to each storage space, but the storage spaces and opening and closing arms may be provided only on either the front or rear side.

A guide mechanism 7 equipped with a freely rotatable guide member 7G is provided on the inner surface of the box frame of the base body 10 at a position protruding outward from the connecting shaft (upper view of FIG. 4, upper view of FIG. 5, and FIG. 7). In this guide mechanism, a freely rotatable roller-shaped guide member is provided between the opposing surfaces of the side surface of the transport cart and the inner surface of the running wall, and when the transport cart is towed and fixed by the left and right towing arms, the planar position of the transport cart is guided to suppress excessive directional displacement of the transport cart relative to the running wall.
In the first embodiment shown in Figures 7, 9 and 10, the towing jig is provided with a vertical connecting pin that can be connected to the towing arm, and a guide mechanism having two disk-shaped guide members that are supported on a shaft so as to be freely rotatable is provided at the front and rear corner positions of an overhanging plate that overhangs outward in a plan view and in the front-rear direction from the connecting pin. The guide member 7G is provided with a part of its free rotation portion protruding to a position that overhangs outward to the side from the connecting shaft position of the connecting pin 7P. Furthermore, a guide bumper 3G that is a trapezoidal plate in plan view and abuts against the guide member 7G is provided on the inner surface of the running wall that faces the guide bumper in the towing connection state (Figure 7).
In the second embodiment shown in Figures 11 and 12, a single towing jig is attached across the left and right sides of the transport cart on the frame. In the third embodiment shown in Figure 13, separate towing jigs are attached to the left and right sides of the transport cart on the frame.

The towing jig is provided at its protruding end with a vertical or horizontal connecting pin that can be connected to the towing arm. In the embodiment, the connecting pins are fixed vertically facing outward from each side position of the transport cart, and are loosely inserted within the storage space of the towing arm 3, resulting in a fixed towing state.

Other Embodiments
Although several embodiments of the present invention have been described, the present invention is not limited to the configurations and various conditions shown in each embodiment, and these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the scope of the invention and its equivalents described in the claims.

Self-supporting structure 100
Running wall 1
Base body 10
Suspension structure 1S
Vertical frame 11
Horizontal frame 12
Internal frame 13
Transport Cart T
Connector 2
Connecting frame 21
Reinforcing plate 22
Towing arm 3
Opening and closing frame 31
Self-propelled wheel 4
Mecanum Wheel 41
Driving device 5
Battery 5B
Motor 5M
Towing tool 7
Connecting pin 7P
Connecting pin pitch 63PL
Guide Bumper 64
Guide material 64A
Camera C
Sensor S
Towing jig 7
Connecting pin 7P
Control device 8
Wheelbase distance (WL) between the front and rear self-propelled wheels
Wheelbase center range (center 1/3 range of wheelbase distance) 4BC
Towing position 3P
Wheelbase center WC
Centroid TX of the transport cart (diagonal center)
Towing Recess 3D

Claims (6)

A transport device comprising a self-supporting structure in which a pair of running walls are arranged on the left and right sides to sandwich a transport cart from both sides and a connecting body is arranged above the transport cart in the left and right direction,
The self-supporting structure includes:
A pair or pairs of left and right running walls arranged so as to be able to run on both sides of the transport cart,
A connecting body is fixed between each of the running walls so as to extend over the top of the transport cart.
Each running wall is
A towing arm provided on the inner surface side for towing the side of the transport cart;
A self-propelled wheel provided at the bottom,
A drive device for the self-propelled wheel is provided inside the self-propelled wheel or on a lower side of the wall surface,
This self-propelled conveying device is characterized in that the conveying cart is towed and fixed from both sides by the towing arms of the left and right running walls without being suspended, lifted, or supported from below, and is transported by self-propelling by a drive unit and self-propelled wheels. The self-propelled transport device according to claim 1, characterized in that the running wall has multiple self-propelled wheels in the front-rear direction, and all towing positions by the towing arm are included within the central 1/3 range of the distance between the axles of the self-propelled wheels at the front and rear ends of the running wall in a plan view. 3. A self-propelled transport device as described in claim 1 or 2, which tows a transport cart that is rectangular in plan view, and the running wall has a plurality of self-propelled wheels in the front-to-rear direction, and is characterized in that, in plan view, the centroid of the transport cart and the diagonal intersection point diagonally connecting the axles of the self-propelled wheels at the front and rear ends of the left and right running walls overlap within the central 1/3 of the distance between the axles of the self-propelled wheels at the front and rear ends of the left and right running walls. The towing arm has an opening and closing frame body that can open and close the space within the frame by opening and closing operations,
In addition, a fixed towing jig having a connecting pin is fixed facing outward at each side position of the transport cart,
4. The self-propelled transport device according to claim 1, wherein the connecting pin of the towing jig is loosely connected by the opening and closing frame of the towing arm. 5. A self-propelled transport device according to claim 1, 2, 3 or 4, characterized in that the towing arms are provided with guide members for guiding the planar position of the transport cart when the transport cart is towed and fixed by the left and right towing arms. A self-propelled transport device according to any one of claims 1, 2, 3, 4, or 5, characterized in that at least one of the multiple self-propelled wheels in each running wall is a Mecanum wheel that rotates around a fixed horizontal axle and has a plurality of oblique barrel-shaped rotating bodies around the outer periphery of the rotating wheel.

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