Transport vehicle

Abstract

To provide a conveying vehicle which can prevent an obstacle from being dragged into a wheel.SOLUTION: An entanglement prevention device 30 comprises: a bumper 31; a swing arm 32 which supports the bumper 31; a grounding component 33 which is arranged at the bumper 31 and grounded on a road surface G. The grounding component 33 and the bumper 31 are constructed to be movable in the vertical direction to prevent the bumper from interacting with irregularity on the road surface G. The entanglement prevention device 30 is arranged at a travel unit 20 so that the bumper 31 can be positioned, even when each of the plurality of traveling units 20 is individually steered, at the front side (- side) in the traveling direction in each of the travel units 20. Thereby, an obstacle can be prevented from being dragged into a wheel 23 of the traveling unit 20.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a transport vehicle, and more particularly to a transport vehicle that can prevent obstacles from getting caught in its wheels. [Background technology]

[0002] There is a known technology in which a rear bumper is provided below the rear of a truck to prevent a passenger car from sliding under the truck in the event of a collision. Patent Document 1 discloses a technology in which the rear bumper is positioned low to prevent a car from sliding under the truck, and the rear bumper is movable up and down relative to the vehicle body to prevent the rear bumper from interfering with unevenness or undulations in the road surface. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Utility Model Application Publication No. 58-33353 (page 5, line 8 to page 6, line 3, Figure 4, etc.) Summary of the Invention [Problem to be solved by the invention]

[0004] Here, in a transport vehicle that has multiple running devices with wheels and that steers each of the multiple running devices individually, it is necessary to prevent obstacles such as a worker's toes from getting caught in the wheels of the running devices.

[0005] However, in the above-mentioned conventional technology, since the bumper is arranged on the vehicle body, there was a problem in that it was difficult to prevent obstacles from getting caught in the wheels of a transport vehicle that can move sideways or diagonally.

[0006] The present invention has been made to solve the above-mentioned problems, and has as its object to provide a transport vehicle that can prevent obstacles from getting caught in the wheels. [Means for solving the problem]

[0007] In order to achieve this object, the transport vehicle of the present invention comprises a traveling device having wheels, and a vehicle body on which a plurality of the traveling devices are arranged, the plurality of traveling devices being configured to be individually steerable, and the wheels of the plurality of traveling devices being individually drivable, a bumper, a support member for supporting the bumper, and To form a gap between the bumper and the road surface the bumper Bottom of and a ground contact member that is disposed on the road surface and is in contact with the road surface, and at least the bumper is configured to be movable up and down together with the ground contact member, and the entrapment prevention device is configured so that the entrapment prevention device is and at least the bumper is disposed on the traveling device. On one side of the direction of travel position will be done. [Effects of the Invention]

[0008] According to the transport vehicle of claim 1, the entanglement prevention device includes a bumper, a support member for supporting the bumper, To create a gap between the bumper and the road surface bumper Bottom of The bumper has a ground contact member that is disposed on the bumper and is brought into contact with the road surface, and at least the bumper is configured to be able to move up and down together with the ground contact member, so that the bumper can be prevented from interfering with unevenness or undulations in the road surface.

[0009] In this case, according to the transport vehicle of claim 1, the entanglement prevention device At least the bumper On one side of the traveling direction of the traveling device position Therefore, even if the plurality of traveling devices are steered individually, the bumper can be positioned on one side of the traveling direction of each traveling device, thereby preventing obstacles from being caught in the wheels of the traveling devices.

[0010] According to the transport vehicle of claim 2, in addition to the effects of the transport vehicle of claim 1, the support member is configured so that the axis connected to the base end is rotatably supported on the running device, and the tip side can move up and down relative to the running device by rotating around the axis, and the bumper is arranged on the tip side of the support member, and an elastic member is interposed between the axis and the running device, and the elastic recovery force of the elastic member can act on the axis as a force in the direction of grounding the ground member to the road surface, thereby improving the ability of the ground member to follow the road surface.

[0011] According to the transport vehicle of claim 3, in addition to the effect of the transport vehicle of claim 2, two or more ground contact members are spaced apart in the width direction of the bumper. Bottom of The elastic member is disposed on the bumper, and the elastic deformation of the elastic member allows for displacement of the shaft in the direction of twisting relative to the traveling device. This makes it easier for the bumper to follow the slope of the road surface when the road surface is inclined in the width direction of the bumper. Also, for example, if only the ground contact member on one side of the bumper in the width direction runs over a convex part of the road surface, the ground contact member on the other side of the bumper in the width direction can be moved closer to the road surface or made to contact the road surface. This prevents the gap between the bumper and the road surface from becoming larger than the reference value in some areas, and prevents obstacles from getting caught in the wheels of the traveling device.

[0012] According to the transport vehicle of claim 4, in addition to the effects of the transport vehicle of any one of claims 1 to 3, the support member is configured such that an axis connected to the base end side is rotatably supported by the traveling device, and the tip side is movable up and down relative to the traveling device by rotating around the axis, the entanglement prevention device has a swing mechanism disposed between the bumper and the support member, and when one side in the width direction of the bumper is raised, the other side in the width direction is lowered, and when one side in the width direction is lowered, the other side in the width direction is raised, Bottom ofSince the bumper is disposed at a distance from the road surface, when the road surface is inclined in the width direction of the bumper, the bumper can be easily aligned with the slope of the road surface. Also, for example, when only the ground contact member on one side of the bumper in the width direction runs over a convex part of the road surface, the ground contact member on the other side of the bumper in the width direction can be brought closer to the road surface or can be brought into contact with the road surface. This prevents the gap between the bumper and the road surface from becoming larger than the reference value in some areas, and prevents obstacles from getting caught in the wheels of the traveling device. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a perspective view of a transport vehicle according to a first embodiment of the present invention. [Figure 2] 2 is a bottom view of the entanglement prevention device as seen in the direction of arrow II in FIG. 1. [Figure 3] 3 is a cross-sectional view of the entanglement prevention device taken along line III-III in FIG. 2. [Figure 4] 4 is a front view of the entanglement prevention device as seen in the direction of arrow IV in FIG. 3. [Figure 5] 5A is a partially enlarged cross-sectional view of the entanglement prevention device taken along line Va-Va in FIG. 4, and FIG. 5B is a partially enlarged cross-sectional view of the entanglement prevention device showing the shaft support mechanism in the initial state. [Figure 6] 10(a) is a bottom view of the entanglement prevention device in the second embodiment, and FIG. 10(b) is a front view of the entanglement prevention device. DETAILED DESCRIPTION OF THE INVENTION

[0014] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. First, the overall configuration of a transfer vehicle 1 will be described with reference to Fig. 1. Fig. 1 is a perspective view of a transfer vehicle 1 in a first embodiment of the present invention.

[0015] 1 indicate the vehicle up-down direction, vehicle width direction (left-right direction), and vehicle front-rear direction of the transport vehicle 1, respectively. The same applies to Fig. 2 and subsequent Figs. 1 and 2. In Fig. 1, the outline of the vehicle body 10 is schematically shown by a two-dot chain line, and the traveling device 20 is shown steered in a straight-ahead direction.

[0016] As shown in Figure 1, the transport vehicle 1 is an automatic guided vehicle that includes a body 10, running devices 20 arranged at multiple locations (four locations in this embodiment) on the body 10, and an anti-entanglement device 30 arranged on each of the multiple running devices 20, and each running device 20 is configured to be able to steer individually, and each wheel 23 of each running device 20 is configured to be able to drive individually.

[0017] The running device 20 comprises a swivel frame 21 configured to be swivelable horizontally relative to the vehicle body 10, an axle housing 22 arranged at the lower end of the swivel frame 21 and accommodating a differential gear and axles (neither of which are shown), a pair of wheels 23 arranged on axles protruding from both ends of the axle housing 22, a drive motor (not shown) that provides driving force to rotate the wheels 23, and a swing motor (not shown) that provides driving force to swing the swivel frame 21.

[0018] The entanglement prevention device 30 is disposed on the axle housing 22 of the traveling device 20. Therefore, when the traveling device 20 is steered, the entanglement prevention device 30 also changes direction together with the traveling device 20, and the bumper 31 is always positioned on the front side in the traveling direction of the traveling device 20 (on one side in the traveling direction). This effectively prevents obstacles (for example, the toes of an operator) from getting caught in the wheels 23.

[0019] The intervals between the traveling devices 20 in the vehicle width direction are set so that the entrapment prevention devices 30 (bumpers 31) do not interfere with adjacent traveling devices 20 when traveling laterally (steering angle 90 degrees).

[0020] The detailed configuration of the entanglement prevention device 30 will be described with reference to Figures 2 to 5. Figure 2 is a bottom view of the entanglement prevention device 30 as viewed in the direction of arrow II in Figure 1. Figure 3 is a cross-sectional view of the entanglement prevention device 30 taken along line III-III in Figure 2. Figure 4 is a front view of the entanglement prevention device 30 as viewed in the direction of arrow IV in Figure 3. Figure 5(a) is a partially enlarged cross-sectional view of the entanglement prevention device 30 taken along line Va-Va in Figure 4, and Figure 5(b) is a partially enlarged cross-sectional view of the entanglement prevention device 30 to show the shaft support mechanism 40 in the initial state.

[0021] 2 to 5, the entrapment prevention device 30 includes a bumper 31, a pair of swing arms 32 that support the bumper 31 on the front side in the traveling direction of the traveling device 20 (one side in the traveling direction), a ground contact member 33 disposed on the bottom surface of the bumper 31, and a pivotal support mechanism 40 that pivotally supports the swing arm 32 on the traveling device 20. In this embodiment, the bumper 31 and the swing arm 32 are made of a metal material. However, the bumper 31 and the swing arm 32 are not limited to a metal material. For example, they may be made of a resin material.

[0022] The bumper 31 is formed as a long member with an L-shaped (mountain-shaped) cross section, and is disposed on the tip side (arrow F direction side) of the swing arm 32 in a direction substantially parallel to the width direction of the traveling device 20 (the axial direction of the axle of the wheels 23). The width dimension of the bumper 31 (dimension in the directions of arrows L and R in FIG. 2) is set to a dimension larger than the width dimension of the traveling device 20 (pair of wheels 23), and the bumper 31 overlaps the pair of wheels 23 in a front view.

[0023] A stay 26 that protrudes downward (in the direction of arrow D) is disposed on the bottom surface of the traveling device 20 (in this embodiment, the bottom surface of the axle housing 22), and a pivotal support mechanism 40 is disposed on the stay 26. A shaft 41 of the pivotal support mechanism 40 is connected (fixed) to the base end side (in the direction of arrow B) of the swing arm 32, and the swing arm 32 is rotated (swings) together with the shaft 41, so that the bumper 31 can move up and down together with the ground contact member 33.

[0024] The ground contact member 33 comprises a mounting seat 33a arranged on the bottom surface of the bumper 31, a fork 33b configured to be rotatable horizontally relative to the mounting seat 33a, and a wheel 33c rotatably supported at the lower end of the fork 33b, and is configured as a swivel caster in which the wheel 33c is positioned away (eccentrically) from the center of rotation of the fork 33b.

[0025] A plurality of ground contact members 33 (two in this embodiment) are arranged at intervals in the width direction (direction of arrows L and R) of the bumper 31. When the ground contact members 33 (wheels 33c) are in contact with the road surface G, a gap of approximately 30 mm is formed between the bumper 31 and the road surface G.

[0026] The shaft support mechanism 40 includes a shaft 41 and a case 42 formed in the shape of a rectangular tube with a substantially square cross section, and a plurality (four) of elastic members 43 formed in a cylindrical shape from a rubber-like elastic body. In this embodiment, the shaft 41 and the case 42 are made of a metal material. However, the shaft 41 and the case 42 are not limited to a metal material. For example, they may be made of a resin material.

[0027] In the initial state (unloaded state) of the support mechanism 40 (see Figure 5(b)), the shaft 41 and the case 42 are arranged with a phase difference of approximately 45 degrees, and elastic members 43 are press-fitted into each of the four spaces between the outer surface (one side) of the shaft 41 and the inner surface (corner portion) of the case 42.

[0028] The external dimensions of the shaft 41 in the diagonal directions (up-down and left-right directions in FIG. 5(b)) are smaller than the opposing dimensions between two opposing sides of the case 42. Therefore, the shaft support mechanism 40 can individually or simultaneously allow (form) a configuration in which the shaft 41 rotates about its own axis and a configuration in which the shaft 41 is displaced in a direction that tilts its own axis relative to the axis of the case 42 (hereinafter referred to as the "prying direction").

[0029] In the initial state, the support mechanism 40 (see Figure 5(b)) has the shaft 41 and case 42 arranged concentrically, and the axial directions of the shaft 41, case 42 and elastic member 43 are arranged approximately parallel to the axial directions of the axles of the running device 20 (directions of arrows L and R).

[0030] When the transport vehicle 1 is positioned on a horizontal road surface G (see FIGS. 3 and 5(a)), the shaft 41 is rotated by an angle θ in the direction of arrow A (see FIG. 5(a)) compared to the shaft support mechanism 40 in its initial state (see FIG. 5(b)). Therefore, the elastic member 43 is elastically deformed (compressively deformed) between the shaft 41 and the case 42, and the elastic recovery force of the elastic member 43 acts on the swing arm 32 (shaft 41) as a force in a direction that causes the ground contact member 33 to touch the ground (the opposite direction to the direction of arrow A in FIG. 5(a)).

[0031] That is, the swing arm 32 is connected (fixed) to the shaft 41 of the shaft support mechanism 40 (see FIG. 5(b)) in the initial state in a state in which it is inclined downward beforehand (a rotation position in which the bumper 31 side is positioned downward). When the transport vehicle 1 is positioned on a horizontal road surface G and the ground contact member 33 touches the road surface G, the bumper 31 is lifted upward, and the swing arm 32 (shaft 41) is rotated in the direction of arrow A by that amount. As a result, the elastic member 43 is brought into an elastically deformed state.

[0032] According to the transport vehicle 1 of this embodiment, when traveling on an uneven or undulating road surface G, the ground contact member 33 (wheel 33c) is rolled along the road surface G, thereby rotating the base end side (shaft 41 of the shaft support mechanism 40) of the swing arm 32 and moving the bumper 31 up and down together with the ground contact member 33. As a result, it is possible to prevent the bumper 31 from interfering with the unevenness or undulations of the road surface G.

[0033] In this case, the entanglement prevention device 30 is disposed on the front side (one side) of each traveling device 20 in the traveling direction, so even if the multiple traveling devices 20 are steered individually, the bumper 31 can be positioned on the front side in the traveling direction of each traveling device 20 regardless of the steering direction. As a result, it is possible to prevent obstacles from being entangled in the wheels 23 of the traveling devices 20.

[0034] As described above, the shaft support mechanism 40 of the entanglement prevention device 30 is configured such that the elastic member 43 is elastically compressed and deformed, and the elastic recovery force of the elastic member 43 can act on the swing arm 32 (shaft 41) as a force in the direction of grounding the ground member 33.

[0035] Therefore, even if the road surface G is uneven or undulating, the ability of the ground contact member 33 (wheel 33c) to follow the road surface G can be improved, and the distance (30 mm in this embodiment) between the bumper 31 and the road surface G can be easily maintained. For example, it is possible to prevent the ground contact member 33 from being bounced up by a protrusion on the road surface G while the transport vehicle 1 is traveling, causing the distance between the bumper 31 and the road surface G to become larger than a reference value (for example, 40 mm).

[0036] Furthermore, in the shaft support mechanism 40 of the entrapment prevention device 30, the elastic member 43 is elastically compressed and deformed in the rotational direction, and as described above, the two ground contact members 33 are arranged at a distance in the width direction of the bumper 31 (directions of arrows L and R), and the shaft 41 is displaceable in the prying direction, so that it is possible to prevent the distance between the bumper 31 and the road surface G from becoming larger than the standard value in part of the width direction of the bumper 31.

[0037] For example, if the road surface G is inclined in the width direction of the bumper 31 (for example, in FIG. 4, if the road surface G on which the ground contact members 33 contact is not parallel to the directions of the arrows L and R), the bumper 31 can be made to follow the slope of the road surface G. Also, for example, if only one ground contact member 33 runs over a convex part of the road surface G, the other ground contact member 33 can be made to approach the road surface G or to contact the road surface G. This makes it possible to prevent the gap between the bumper 31 and the road surface G from becoming larger than the reference value in part of the width direction of the bumper 31.

[0038] Here, for example, it is possible to consider a configuration in which a coil spring is interposed between the swing arm 32 and the swivel frame 21 or the axle housing 22, and the elastic recovery force of the coil spring acts on the swing arm 32 as a force in the direction of bringing the ground contact member 33 into contact with the ground. However, this would require consideration of interference between the coil spring and the vehicle body 10 when steering the running device 20, reducing the degree of freedom in design.

[0039] In contrast to this, in this embodiment, the support mechanism 40 is configured as a unit in which the elastic member 43 is interposed between the shaft 41 and the case 42, and the support mechanism 40 is housed within the stay 26. Therefore, it is not necessary to consider the above-mentioned interference, and the degree of freedom in design can be improved.

[0040] Next, an entanglement prevention device 230 according to a second embodiment will be described with reference to Fig. 6. Fig. 6(a) is a bottom view of the entanglement prevention device 230 according to the second embodiment, and Fig. 6(b) is a front view of the entanglement prevention device 230. Figs. 6(a) and 6(b) correspond to Figs. 2 and 3, respectively. Furthermore, the same parts as those in the first embodiment are given the same reference numerals, and their description will be omitted.

[0041] As shown in FIG. 6, in the entrapment prevention device 230 of the second embodiment, a swing mechanism 250 is interposed between the bumper 31 and the swing arm 32, and the swing arm 32 is pivotally supported on the traveling device 20 by a pivotal support mechanism 240.

[0042] The swing mechanism 250 is a mechanism for swinging the bumper 31 relative to the swing arm 32, and includes a base 251 arranged on the tip side (in the direction of arrow F) of the swing arm 32, and an axis 252 protruding from the base 251 and supporting the center of the width of the bumper 31 so that it can rotate.

[0043] This allows the bumper 31 to swing by rotating about the shaft 252. That is, when one widthwise side (for example, the side in the direction of arrow L) of the bumper 31 is raised, the other widthwise side (the side in the direction of arrow R) is lowered, and when one widthwise side (the side in the direction of arrow L) is lowered, the other widthwise side (the side in the direction of arrow R) is raised.

[0044] The shaft support mechanism 240 includes a bearing (not shown) whose outer ring is disposed on the stay 26, and a shaft 241 disposed on the inner ring of the bearing and coupled (fixed) to the base end side (the side in the direction of arrow B) of the swing arm 32. Therefore, by rotating the swing arm 32 together with the shaft 241, the bumper 31 can move up and down together with the ground contact member 33.

[0045] According to the entrapment prevention device 230 of this embodiment, the bumper 31 is made swingable, so as in the first embodiment, it is possible to prevent the distance between the bumper 31 and the road surface G from becoming larger than the standard value in part of the width direction of the bumper 31.

[0046] For example, if the road surface G is inclined in the width direction of the bumper 31 (for example, in FIG. 6(b) , if the road surface G on which the ground contact members 33 contact is not parallel to the directions of the arrows L and R), the bumper 31 can be aligned with the inclination of the road surface G. Also, for example, if only one ground contact member 33 runs over a convex part of the road surface G, the other ground contact member 33 can be moved closer to the road surface G or can be brought into contact with the road surface G. This makes it possible to prevent the gap between the bumper 31 and the road surface G from becoming larger than the reference value in part of the width direction of the bumper 31.

[0047] The present invention has been described above based on an embodiment, but the present invention is not limited to the above embodiment, and it can be easily inferred that various improvements and modifications are possible within the scope of the present invention.

[0048] The numerical values ​​given in the above embodiment are merely examples, and other numerical values ​​can of course be adopted. For example, the distance between the bumper 31 and the road surface G can be set arbitrarily, and may be smaller or larger than 30 mm.

[0049] The number of ground contact members 33 may be one or three or more. For example, if there are no grooves (depressions) in the road surface G, using only one ground contact member 33 can reduce parts costs. The ground contact members 33 may be disposed at any position, and may be disposed symmetrically with respect to the center of the width of the bumper 31 (at the center of the width of the bumper 31 when there is only one ground contact member 33), or may be disposed offset to one side or the other of the center of the width of the bumper 31. For example, the offset direction may be different between the traveling unit 20 on the left side of the vehicle and the traveling unit 20 on the right side of the vehicle, so that each ground contact member 33 is disposed toward the center of the vehicle width of the transport vehicle 1. This makes it less likely that a worker's toes will be stepped on by the ground contact members 33.

[0050] The above embodiments may be combined to form new embodiments. For example, the swing mechanism 250 of the second embodiment may be added to the entanglement prevention device 30 of the first embodiment.

[0051] In the above embodiments, the front side of the bumper 31 (the forward side in the traveling direction of the traveling device 20) has a shape that extends linearly in the width direction of the bumper 31 in a plan view (as viewed in the direction of arrow D), but it may have a shape that is curved in an arc that is convex toward the forward side in the traveling direction of the traveling device 20 in a top view (for example, an arc shape centered on the turning center of the turning frame 21). This prevents interference between the bumper 31 and the vehicle body 10 when steering the traveling device 20, improving the degree of freedom in design.

[0052] In the above embodiments, the bumper 31 is formed from a member with an L-shaped cross section, but it may be formed from a member with another cross-sectional shape. Examples of members with other end face shapes include solid members with a circular or rectangular cross section, pipe members with a circular cross section, hollow rectangular tubular members, and I-beam steel members.

[0053] In the above embodiments, the case where the entanglement prevention device 30, 230 is disposed only on the front side (one side) of the traveling device 20 in the traveling direction has been described, but in addition to this, the entanglement prevention device 30, 230 may also be disposed on the rear side (other side) of the traveling device 20 in the traveling direction. This can prevent obstacles from getting entangled in the wheels 23 even when the traveling device 20 is moving backward.

[0054] Although not explained in the above embodiments, a sensor for detecting contact with an obstacle may be provided on the bumper 31, and the running state of the transport vehicle 1 (traveling device 20) may be controlled (for example, slowed down or stopped when contact is detected) according to the detection result of the sensor.

[0055] In the first embodiment, the ground contact member 33 is disposed on the bumper 31, but the ground contact member 33 may be disposed on the swing arm 32.

[0056] In the first embodiment, the elastic recovery force of the elastic member 43 of the pivot mechanism 40 is used to press the ground contact member 33 against the road surface G. However, instead of or in addition to this, the elastic recovery force of a known biasing means (for example, a coil spring or a leaf spring) may be used. This is also true in the second embodiment.

[0057] In the above first embodiment, when the transport vehicle 1 is positioned on a horizontal road surface G, the support mechanism 40 is rotated from the initial position in the direction of arrow A, and the elastic member 43 is elastically deformed. However, the support mechanism 40 may be configured to be in its initial state (a state in which the elastic member 43 is not elastically deformed in the direction of arrow A or the direction opposite to arrow A, as shown in Figure 5 (B)) when the transport vehicle 1 is positioned on a horizontal road surface G.

[0058] In this case, the spring characteristics (elastic modulus) of the elastic member 43 may be set so that the bumper 31 is displaced downward due to the weight of the bumper 31, swing arm 32, and ground contact member 33. Even when the road surface G is inclined downward, the ground contact member 33 (wheel 33c) can be made to follow the road surface G.

[0059] In the above embodiments, one entrapment prevention device 30 is provided on one traveling device 20. However, a plurality of entrapment prevention devices 30 may be provided side by side on one traveling device 20 in the vehicle width direction (the axial direction of the axles of the wheels 23). That is, a pair of stays 26 is provided as a set, and a plurality of sets of stays 26 are provided side by side on the axle housing 22 at closer intervals than in the above embodiments, and each set of stays 26 supports an entrapment prevention device 30 having a bumper 31 with a smaller width dimension than in the above embodiments. In one traveling device 20, each set of entrapment prevention devices 30 can be moved up and down (and swung) individually. Therefore, when the road surface G is inclined in a stepped manner in the width direction of the bumper 31 or when only the ground contact members 33 of some of the entrapment prevention devices 30 run over a convex part of the road surface G, it is possible to prevent the distance between each bumper 31 and the road surface G from becoming larger than the reference value.

[0060] In the above embodiments, the bumper 31 is positioned inside the outer shape of the vehicle body 10 in a plan view (as viewed in the direction of arrow D) at least when traveling straight, but the bumper 31 may be configured to be positioned outside the outer shape of the vehicle body 10 in a plan view at least when traveling straight. The bumper 31 can be made to abut against an obstacle before the vehicle body 10.

[0061] In the above embodiments, the ground contact member 33 is configured as a swivel caster, but other configurations may be adopted. Examples of other configurations include a ball caster (which includes a sphere (ball) and a holder that rotatably holds the sphere).

[0062] In the above embodiments, the case where all of the traveling devices 20 arranged on the vehicle body 10 are steered has been described, but it is also possible to have a configuration where only some of the traveling devices 20 are steered. Similarly, the case where the wheels 23 of all of the traveling devices 20 arranged on the vehicle body 10 are driven has been described, but it is also possible to have a configuration where the wheels 23 of only some of the traveling devices 20 are driven. [Explanation of symbols]

[0063] 1 Transport vehicle 10. Body 20 Running gear 23 wheels 30,230 Entrapment prevention device 31 Bumper 32 Swing arm (support member) 33 Grounding member 41,241 axes 43 Elastic member 250 Swing Mechanism G road surface

Claims

1. A transport vehicle comprising a traveling device having wheels and a vehicle body on which a plurality of the traveling devices are arranged, wherein the plurality of traveling devices are configured to be individually steerable and the wheels of the plurality of traveling devices are configured to be individually drivable, a bumper, a support member for supporting the bumper, and a ground contact member disposed on the bottom surface of the bumper to form a gap between the bumper and the road surface and contacting the road surface, wherein at least the bumper is configured to be movable up and down together with the ground contact member; The transport vehicle is characterized in that the entanglement prevention device is disposed on the traveling device, and at least the bumper is positioned on one side of the traveling device in the traveling direction.

2. The support member is configured such that a shaft connected to a base end side thereof is rotatably supported by the traveling device, and the tip side thereof is movable up and down relative to the traveling device by rotating about the shaft, the bumper is disposed on the tip side of the support member, The transport vehicle according to claim 1, characterized in that an elastic member is interposed between the shaft and the running device, and the elastic recovery force of the elastic member is configured to act on the shaft as a force in a direction that brings the grounding member into contact with the road surface.

3. Two or more ground contact members are disposed on the bottom surface of the bumper at intervals in the width direction of the bumper, 3. The transport vehicle according to claim 2, wherein the elastic member is elastically deformed to allow displacement of the shaft in a twisting direction relative to the traveling device.

4. The support member is configured such that a shaft connected to a base end side thereof is rotatably supported by the traveling device, and the tip side thereof is movable up and down relative to the traveling device by rotating about the shaft, the entanglement prevention device includes a swing mechanism disposed between the bumper and the support member, and the swing mechanism allows the bumper to lower one widthwise side when one widthwise side is raised and to raise the other widthwise side when the one widthwise side is lowered, 4. The transport vehicle according to claim 1, wherein two or more of the ground contact members are disposed on the bottom surface of the bumper at intervals in the width direction of the bumper.

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