Heavy-duty transport vehicles with running boards

Abstract

To provide a heavy load carrying vehicle configured so that a mechanism for adjusting an interval of a running board can be fixed to a loading platform simply and easily and further with sufficient strength.SOLUTION: A heavy load carrying vehicle is equipped with: a driving shaft 3 connected to a rear end of a loading platform 11; a running board 1 connected to the driving shaft 3; an actuator 4 that rotates the driving shaft 3 to tilt the running board 1; and an interval adjusting mechanism 5 that moves the running board 1 along the driving shaft 3. The interval adjusting mechanism 5 is an assembly unit 10 that comprises a base plate 6 fixed in a width direction to the loading platform 11, a swing arm 8 whose one end is connected to a first connection portion 7A of the base plate 6 and whose other end is connected to the running board 1, and a cylinder 9 whose one end is connected to a middle of the swing arm 8 and whose other end is connected to a second connection portion 7B of the base plate 6, which turns the swing arm 8 in a horizontal surface. The base plate 6, in which the first connection portion 7A and the second connection portion 7B are separated from each other in the width direction, is fixed to the loading platform 11 to fix the swing arm 8 and the cylinder 9 to the loading platform 11.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a vehicle for transporting heavy objects such as bulldozers and road rollers on a loading platform, and relates to a transport vehicle having a running board at the rear end of the loading platform. [Background technology]

[0002] A heavy-duty transport vehicle has a pair of rungs at the rear end of the loading platform. This transport vehicle allows a self-propelled heavy-duty transport vehicle, such as a bulldozer that runs on caterpillar® or a road roller that runs on wheels, to run over the rungs and be loaded onto the loading platform. Since the caterpillar® or wheels on both sides of this transport vehicle run over the rungs to load the heavy object onto the loading platform, the spacing between the pair of rungs must be adjusted to fit the caterpillar® or vehicle on both sides.

[0003] The present inventors have developed a transport vehicle in which the spacing between running boards is adjusted using an extendable cylinder (see Patent Document 1). Fig. 8 is a schematic plan view of a spacing adjustment mechanism 905 for running boards 901 of a transport vehicle 900 disclosed in Patent Document 1. The spacing adjustment mechanism 905 in this figure includes a rectangular column-shaped slide shaft 903 rotatably positioned at the rear end of a loading platform 911 in an orientation extending in the width direction, a pair of running boards 901 that can move in the width direction of the loading platform 911 along the slide shaft 903, and an assembly unit 910 that moves the running boards 901 along the slide shaft 903 to adjust the spacing between the pair of running boards 901. The assembly unit 910 includes a swing arm 908 connected to the rear end of the running board 901 via a guide pin 908a, and a cylinder 904 that rotates the swing arm 908 in a horizontal plane to move the running board 901 along the slide shaft 903. The swing arm 908 is connected to the underside of the loading platform 911 via a connecting shaft 909 so as to be rotatable within a horizontal plane. The connecting shaft 909 is fixed to the underside of the loading platform 911 in a vertical position so that the swing arm 908 can be rotated within a horizontal plane below the loading platform 911. The connecting shaft 909 rotatably passes through the middle of the swing arm 908. Furthermore, the rear end of the swing arm 908 is connected to the tip of an extendable rod 904A of a cylinder 904. The rear end of the cylinder 904 is connected to the underside of the loading platform 911 via a rotating shaft 912 in an position approximately perpendicular to the swing arm 908 so as to extend and retract to rotate the swing arm 908.

[0004] 9 and 10 show the connection structure between the swing arm 908 and running board 901. The running board 901 in these figures is provided with a guide groove 902 that guides the guide pin 908a of the swing arm 908. The guide groove 902 is provided at the rear end of the running board 911 in an arc shape centered on the drive shaft 903 so that the guide pin 908a can be guided when the running board 901 is tilted in a vertical plane. In this connection structure, the guide pin 908a, guided by the guide groove 902, moves in the width direction of the platform 911, causing the running board 911 to move along the drive shaft 903. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Utility Model Application Publication No. 2-103843 Summary of the Invention [Problem to be solved by the invention]

[0006] The above-mentioned gap adjustment mechanism can adjust the gap between the rungs by extending and retracting the cylinder, but it is extremely time-consuming to attach the gap adjustment mechanism to the underside of the bed, and because the upper end of the connecting shaft is fixed to the underside of the bed to connect the swing arm and cylinder to the bed, it is difficult to ensure that the fixed part of the connecting shaft is strong enough.Furthermore, because the cylinder is located perpendicular to the rear end of the swing arm, the structure requires the cylinder to be connected in a position that extends laterally to the long swing arm, which is a drawback that requires a large installation area.

[0007] The present invention was developed with the further objective of overcoming the above drawbacks, and one object of the present invention is to provide a heavy-duty transport vehicle in which a running board distance adjustment mechanism can be simply and easily installed on the loading platform. Another object of the present invention is to provide a heavy-duty transport vehicle in which the swing arm and cylinder of the distance adjustment mechanism can be fixed to the loading platform with sufficient strength so that they can be installed in a small area under the loading platform. Means for solving the problems and effects of the invention

[0008] A heavy-duty transport vehicle according to one embodiment of the present invention comprises a drive shaft rotatably connected to the rear end of the platform in a position extending in the width direction, a running board connected to the drive shaft in a non-rotating state so as to be movable in the axial direction, an actuator that rotates the drive shaft to tilt the running board in a vertical plane, and a mechanism that moves the running board in the width direction of the platform along the drive shaft. Adjust the spacing of the stepsThe distance adjustment mechanism is comprised of an assembly unit including a base plate fixed to the loading platform in a position extending in the width direction, a swing arm having one end connected to a first connecting part of the base plate so as to be rotatable in a horizontal plane and the other end connected to the running board, and a cylinder having one end connected to the middle of the swing arm and the other end connected to a second connecting part of the base plate so as to be rotatable in a horizontal plane, the cylinder itself extending and contracting to rotate the swing arm in a horizontal plane. The base plate of the assembly unit has a first connecting part and a second connecting part arranged apart in the width direction of the loading platform, and the base plate of the assembly unit is fixed to the loading platform, and the swing arm and the cylinder are connected to the loading platform via the base plate. Place in the designated position are.

[0009] In the above-described heavy-duty transport vehicle, the gap adjustment mechanism for adjusting the gap between the rungs is configured as an assembly unit in which a swing arm and a cylinder are connected to a base plate fixed to the loading platform. The base plate is fixed to the loading platform, and the assembly unit is mounted on the loading platform, allowing both the swing arm and the cylinder to be positioned in fixed positions on the loading platform. Therefore, unlike conventional gap adjustment mechanisms, it is not necessary to connect the swing arm to a fixed position on the loading platform, and then connect the front end of the cylinder to the swing arm and the rear end of the cylinder to the loading platform. Instead, the assembly unit in which the swing arm and the cylinder are connected to the base plate is fixed to the loading platform, and both the swing arm and the cylinder provided on the assembly unit can be mounted in fixed positions on the loading platform. This has the advantage that both the swing arm and the cylinder can be simply and easily fixed in accurate positions on the loading platform. This is because both the swing arm and the cylinder can be mounted in fixed positions on the loading platform by connecting both the swing arm and the cylinder to the base plate to form an assembly unit, and then fixing the base plate of this assembly unit to the loading platform.

[0010] Furthermore, in the above-described heavy-duty transport vehicle, the swing arm and cylinder are not directly connected to the bed as in the past, but are connected to a base plate to form an assembly unit, the base plate of the assembly unit is fixed to the bed, and the swing arm and cylinder are connected to fixed positions on the bed via the base plate, so that they can be installed on the bed with sufficient strength. In particular, the bed connection part of the swing arm and cylinder can be connected to the bed with sufficient strength. Furthermore, because the assembly unit fixed to the bed can be made compact by connecting the cylinder midway through the swing arm, another advantage is realized that the swing arm and cylinder can be efficiently arranged in a narrow area under the bed.

[0011] In another embodiment of the heavy-duty transport vehicle of the present invention, the base plate has metal plates fixed to the base plate at the first connecting portion and the second connecting portion, and the swing arm and cylinder are rotatably connected to the metal plates via connecting pins.

[0012] In the above-described heavy-duty transport vehicle, both the swing arm and the cylinder can be simply and easily fixed to the exact position on the loading platform. This is because the first and second connecting parts are provided on a metal plate fixed to the base plate, and the swing arm and the cylinder can be rotatably connected to the metal plate via a connecting pin. Furthermore, the metal plate fixed to the base plate allows the swing arm and the cylinder of the gap adjustment mechanism to be fixed to the loading platform with sufficient strength.

[0013] In another embodiment of the heavy-duty transport vehicle of the present invention, the base plate has a pair of metal plates at the first connecting portion and the second connecting portion, and the swing arm and cylinder each have one end positioned between the pair of metal plates and are connected via a connecting pin so as to be freely rotatable in a horizontal plane.

[0014] In the above-described heavy-duty transport vehicle, both the swing arm and the cylinder can be simply and easily fixed to the exact position on the loading platform. This is because the pair of metal plates fixed to the base plate are provided with a first connecting portion and a second connecting portion, and the swing arm and the cylinder can be rotatably connected to the metal plates via a connecting pin. Furthermore, the pair of metal plates fixed to the base plate can securely fix the swing arm and the cylinder of the gap adjustment mechanism to the loading platform with sufficient strength.

[0015] In another embodiment of the heavy-duty transport vehicle of the present invention, the platform has lateral ribs extending in the width direction on the underside thereof, and the base plate is fixed to the vertical surfaces of the lateral ribs.

[0016] In the above-described heavy-duty transport vehicle, the base plate is fixed to the vertical surface of the horizontal rib of the loading platform, so that the base plate of the spacing adjustment mechanism can be simply and easily fixed in the correct position and posture, and the swing arm and cylinder can be fixed in the correct position on the loading platform with sufficient strength.

[0017] In another embodiment of the heavy-duty transport vehicle of the present invention, the loading platform has vertical ribs extending vertically on its underside, and the base plate comprises a horizontal plate portion fixed to the horizontal ribs and a vertical plate portion fixed to the vertical surface of the vertical ribs.

[0018] In the above-described heavy-duty transport vehicle, the horizontal plate portions of the base plate are fixed to the horizontal ribs of the loading platform, and the vertical plate portions are fixed to the vertical ribs of the loading platform, so that the base plate can be firmly fixed to the loading platform via both the horizontal ribs and the vertical ribs. By fixing the horizontal plate portions and the vertical plate portions of the base plate to the loading platform via the horizontal ribs and the vertical ribs in this way, the base plate can be positioned more accurately, and the swing arm and cylinder can be more firmly fixed in the correct orientation relative to the loading platform. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is a schematic horizontal cross-sectional view showing the rear part of the loading platform of a vehicle for transporting heavy objects according to one embodiment of the present invention. [Figure 2] FIG. 2 is a schematic cross-sectional perspective view showing the gap adjustment mechanism. [Figure 3] FIG. 3 is a schematic horizontal cross-sectional view showing a state in which the cylinder extends and retracts and the swing arm rotates in a horizontal plane. [Figure 4] FIG. 4 is a schematic vertical cross-sectional view showing the state in which the running board tilts. [Figure 5] FIG. 5 is a schematic vertical cross-sectional view showing an actuator that rotates a drive shaft. [Figure 6] FIG. 6 is a schematic rear view of the transport vehicle as seen from the rear. [Figure 7] FIG. 7 is a schematic horizontal cross-sectional view showing the grease-up mechanism. [Figure 8] FIG. 8 is a plan view showing a conventional gap adjustment mechanism for a heavy load transport vehicle. [Figure 9] FIG. 9 is a cross-sectional view showing a mounting portion of a vertically standing running board of a conventional heavy-duty transport vehicle. [Figure 10] FIG. 10 is a cross-sectional view showing a mounting portion of a horizontally inclined running board of a conventional heavy-duty transport vehicle. DETAILED DESCRIPTION OF THE INVENTION

[0020] The present invention will be described in detail below with reference to the drawings. In the following description, terms indicating specific directions or positions (e.g., "upper," "lower," and other terms incorporating these terms) will be used as necessary. However, the use of these terms is intended to facilitate understanding of the invention with reference to the drawings, and the meaning of these terms does not limit the technical scope of the present invention. Furthermore, parts with the same reference numerals appearing in multiple drawings indicate the same or equivalent parts or components. Furthermore, the embodiments described below are illustrative examples of the technical concept of the present invention and do not limit the scope of the present invention. Furthermore, unless otherwise specified, the dimensions, materials, shapes, relative positions, etc. of the components described below are intended for illustrative purposes only and are not intended to limit the scope of the present invention. Furthermore, the content described in one embodiment or example may also be applicable to other embodiments or examples. Furthermore, the sizes and positional relationships of components shown in the drawings may be exaggerated for clarity.

[0021] (Heavy load transport vehicle 100) 1 to 6 show a heavy-duty transport vehicle according to one embodiment of the present invention. Fig. 1 is a schematic horizontal cross-sectional view showing the rear portion of the platform of a heavy-duty transport vehicle 100, Fig. 2 is a schematic cross-sectional perspective view of a distance adjustment mechanism 5, Fig. 3 is a schematic horizontal cross-sectional view showing a state in which a cylinder 9 extends and retracts, causing a swing arm 8 to pivot in a horizontal plane, Fig. 4 is a schematic vertical cross-sectional view showing a state in which a running board is tilted, Fig. 5 is a schematic vertical cross-sectional view showing an actuator that rotates a drive shaft, and Fig. 6 is a schematic rear view of the transport vehicle as seen from the rear. The heavy-duty transport vehicle 100 shown in Figs. 1 to 6 includes a drive shaft 3 that is positioned close to the rear end of the platform 11 and in a horizontal position extending in the width direction of the platform 11, a pair of running boards 1 that are connected to the drive shaft 3 non-rotatably but movably in the axial direction, and a distance adjustment mechanism 5 that adjusts the distance by moving the running boards 1 along the drive shaft 3. In this specification, the width direction of the loading platform refers to the left-right direction when the transport vehicle is viewed from above, and the length direction of the loading platform refers to the front-rear direction when the transport vehicle is viewed from above.

[0022] (Drive shaft 3) The drive shaft 3 is a metal rod with a polygonal cross section such as a square, and is rotatably connected to the platform 11 along the rear edge of the platform 11. As shown in Figures 1, 2, 5, and 6, the drive shaft 3 is rotatably connected to the platform 11 via a support plate 13 fixed vertically to the rear surface of the platform 11. The drive shaft 3 in Figures 1 and 6 is connected to the platform 11 at both ends and the middle via the support plate 13, and a downward-protruding pivot arm 14 is fixed to the center. The drive shaft 3 is rotated by an actuator 4 to tilt the running board 1 in a vertical plane. Figure 5 shows the actuator 4 that rotates the drive shaft 3. This actuator 4 is a tilting cylinder 4A, and the tip of the rod is connected to the lower end of the pivot arm 14 fixed to the drive shaft 3 so that it can rotate in a vertical plane. Furthermore, the rear end of the tilting cylinder 4A is connected to the underside of the platform 11 so that it can rotate in a vertical plane. This actuator 4 extends and retracts the rod of the tilting cylinder 4A, rotating the drive shaft 3 via the pivot arm 14. The drive shaft 3 tilts the running board 1 in a vertical plane as the tilting cylinder 4A extends and retracts. The running board 1 is in a vertically upright position when the transport vehicle is traveling, and is in a position where it slopes downward from the loading platform 11 toward the tip when loading or unloading a heavy load.

[0023] (Stepping board 1) As shown in Figures 2, 4, and 6, the running board 1 has a rectangular hole 1a extending laterally, through which the drive shaft 3 is inserted, and the drive shaft 3 is slidably inserted. Furthermore, the running board 1 has a guide groove 2 that connects the tip of the swing arm 8 of the distance adjustment mechanism 5. The running board 1 shown in the figures is structured so that it can be detachably connected to the drive shaft 3. The running board 1 shown in the figures has a connecting portion 20 at its end on the loading platform 11 side for detachably connecting to the drive shaft 3. The connecting portion 20 shown in the figures has a U-shaped fitting recess 21 that guides the rectangular column-shaped drive shaft 3 in a fitted state, and a closing member 22 that closes the opening of the fitting recess 21.

[0024] The U-shaped fitting recess 21 includes an outer frame 23 that covers the outside of the rectangular column-shaped drive shaft 3, multiple sliding plates 24 fixed inside the outer frame 23 in parallel positions along the axial direction of the drive shaft 3, and a pair of opposing plates 25 fixed to the center of the axial direction of the drive shaft 3. The outer frame 23 has a U-shaped cross section formed by bending a metal plate, and multiple sliding plates 24 and a pair of opposing plates 25 are fixed to the inner surface. The multiple sliding plates 24 are plate-shaped and U-shaped in side view, and have internal sliding grooves 26 that conform to the external shape of the rectangular column-shaped drive shaft 3. The pair of opposing plates 25 also have internal sliding grooves 26 that conform to the external shape of the rectangular column-shaped drive shaft 3 so that they can be attached to and detached from the drive shaft 3. Furthermore, the pair of opposing plates 25 have a curved edge portion facing the loading platform 11, and this curved portion 25a protrudes from the outer frame 23. The outer frame 23 is partially cut out to allow the curved portions 25a of the pair of opposing plates 25 to protrude outward. The connecting portion 20 of the running board 1 allows the multiple sliding plates 24 and the sliding grooves 26 of the opposing plates 25 to slide relative to the drive shaft 3, allowing the running board 1 to slide in the axial direction of the drive shaft 3. In this way, the connecting portion 20, which connects the running board 1 to the drive shaft 3 via the sliding grooves 26 of the sliding plates 24 and the opposing plates 25, has the advantage of allowing the running board 1 to slide relative to the drive shaft 3 with low resistance. Applying a lubricant such as grease to these sliding portions allows for even lower sliding resistance. Furthermore, the mating recess 21 has a pair of opposing plates 25 spaced apart in the axial center of the drive shaft 3, and the space between these opposing plates 25 forms a guide groove 2 that guides the guide pin 8a provided at the tip of the swing arm 8.

[0025] The above-described connecting portion 20 connects the running board 1 to the drive shaft 3 by closing the opening of the fitting recess 21 with a closing member 22 to prevent it from coming loose. The closing member 22 shown in the figure closes the opening of the fitting recess 21 by fastening opposing opening edges of the outer frame 23 with fixing bolts 27. The closing member 22 further includes a closing block 28 that closes the sliding groove 26 of a pair of opposing plates 25. The closing block 28 is fitted into the opening of the sliding groove 26 and fixed, closing the opposing surfaces of the pair of opposing plates 25 so that they are flat. The pair of opposing plates 25 form a guide groove 2 with a gap that is approximately equal to or slightly larger than the outer diameter of the guide pin 8a of the swing arm 8. As shown in FIG. 4 , this guide groove 2 is located on a rotational trajectory centered on the drive shaft 3 and guides the guide pin 8a of the swing arm 8. When the running board 1 tilts, the guide pin 8a of the swing arm 8 is slidably guided in the guide groove 2. The guide pin 8 a guided by the guide groove 2 moves the running board 1 along the drive shaft 3 by means of a swing arm 8 which rotates in a horizontal plane.

[0026] (Space adjustment mechanism 5) The gap adjustment mechanism 5 moves the rungs 1 along the drive shaft 3 to adjust the gap to that of the caterpillar (registered trademark) or other heavy machinery that loads and unloads onto the platform 11. The heavy-duty transport vehicle 100 is provided with a pair of rungs 1 at the rear end of the platform 11, and a gap adjustment mechanism 5 is connected to each rung 1. Therefore, the transport vehicle 100 is equipped with a pair of rungs 1 and a pair of gap adjustment mechanisms 5. Each gap adjustment mechanism 5 moves each rung 1 separately along the drive shaft 3 to adjust the position of the rung 1 and adjust the gap, or both gap adjustment mechanisms 5 can be synchronized to move both rungs 1 in opposite directions to adjust the gap.

[0027] The gap adjustment mechanism 5 includes a swing arm 8 connected to the running board 1. The swing arm 8 moves the running board 1 along the drive shaft 3 to adjust the position of the running board 1. This gap adjustment mechanism 5 is an assembly unit 10 in which the swing arm 8 and cylinder 9 are connected to a base plate 6. The assembly unit 10 fixes the base plate 6 to the loading platform 11, and installs the swing arm 8 and cylinder 9 in fixed positions on the loading platform 11. The base plate 6 is fixed in a position extending in the width direction of the loading platform 11. The base plate 6 has a first connecting portion 7A and a second connecting portion 7B spaced a predetermined distance from each other. The first connecting portion 7A connects one end of the swing arm 8 to the swing arm 8 so that it can rotate freely in a horizontal plane. The swing arm 8 has a guide pin 8a at the other end that connects to the guide groove 2 of the running board 1. The second connecting portion 7B connects the cylinder 9 so that it can rotate freely in a horizontal plane. The tip of this cylinder 9 is connected to the middle of the swing arm 8 and extends and retracts itself, rotating the swing arm 8 in a horizontal plane and moving the running board 1 along the drive shaft 3.

[0028] The base plate 6 positions the first connecting portion 7A and the second connecting portion 7B apart in the width direction of the loading platform 11. The assembly unit 10 of the gap adjustment mechanism 5 fixes the base plate 6 to the loading platform 11 and positions the swing arm 8 and the cylinder 9 in fixed positions on the loading platform 11. The base plate 6 is a thick metal plate, and metal plates 16 are welded and fixed to the first connecting portion 7A and the second connecting portion 7B. The swing arm 8 and the cylinder 9 are rotatably connected to the metal plates 16 via connecting pins 17. The base plate 6 in FIG. 2 has a pair of metal plates 16 fixed to the first connecting portion 7A and the second connecting portion 7B, and the rear ends of the swing arm 8 and the cylinder 9 are positioned between the pair of metal plates 16. The swing arm 8 is connected to the base plate 6 by inserting the connecting pin 17 through the pair of metal plates 16 and the rear end thereof so as to be rotatable in a horizontal plane. The cylinder 9 is connected to the base plate 6 via a pair of metal plates 16 and a connecting pin 17 inserted through the rear end so that it can rotate in a horizontal plane. The swing arm 8 and the cylinder 9 are provided at their rear ends with connecting holes through which the connecting pin 17 is inserted so that they can rotate.

[0029] The base plate 6 is fixed to the vertical surfaces of the horizontal ribs 11a, which are fixed to the underside of the cargo bed 11 in a position extending in the width direction. Furthermore, the base plate 6 in FIG. 2 is also fixed to the vertical surfaces of the vertical ribs 11b, which are fixed to the underside of the cargo bed 11 in a position extending in the vertical direction. The base plate 6 includes a horizontal plate portion 6a, which is fixed to the vertical surfaces of the horizontal ribs 11a, and a vertical plate portion 6b, which is fixed to the vertical surfaces of the vertical ribs 11b. The base plate 6 in FIG. 2 has the vertical plate portion 6b connected to the end of the horizontal plate portion 6a at a right angle, thereby connecting the horizontal plate portion 6a and the vertical plate portion 6b into an integral structure. This base plate 6 is fixed to both the horizontal ribs 11a and the vertical ribs 11b of the cargo bed 11, allowing it to be firmly fixed to the cargo bed 11. The corners of the horizontal plate portion 6a and the vertical plate portion 6b form second connecting portions 7B, and the end of the horizontal plate portion 6a away from the corners forms first connecting portions 7A. The structure in which the corner between the horizontal plate portion 6a and the vertical plate portion 6b is used as the second connecting portion 7B to connect the cylinder 9 has the advantage of making the connecting portion of the cylinder 9 strong, allowing the swing arm 8 to rotate smoothly with the extending and contracting cylinder 9.

[0030] The swing arm 8 is a metal plate extending from the base plate 6 toward the running board 1. It extends from a slit 12a in a cover plate 12 provided at the rear end of the loading platform 11 into the guide groove 2 of the running board 1, guiding the guide pin 8a at its tip into the guide groove 2 of the running board 1. The cover plate 12 is fixed in a vertical position to the rear end surface of the loading platform 11 and has a horizontal slit 12a extending in the width direction of the loading platform 11. The guide pin 8a at the tip of the swing arm 8 slides inside the guide groove 2 of the tilting running board 1. The running board 1 is connected to the swing arm 8, guiding the guide pin 8a at the tip of the swing arm 8. Therefore, when the swing arm 8 rotates in a horizontal plane, the guide pin 8a moves the running board 1 along the drive shaft 3. The guide pin 8a is fixed by screwing it into a female threaded hole in the swing arm 8 so that it can be attached and detached. The swing arm 8, which is connected so that the guide pin 8a can be detachably attached, can be inserted into a slit 12a provided in a cover plate 12 of the cargo bed 11 after removing the guide pin 8a. The cover plate 12 shown in Fig. 5 has an insertion opening 12b for the guide pin 8a in the slit 12a, so that the swing arm 8 to which the guide pin 8a is fixed can be inserted.

[0031] The gap adjustment mechanism 5 connects the swing arm 8 and the cylinder 9 to the base plate 6 to form an assembly unit 10, which is fixed to the underside of the loading platform 11. When the assembly unit 10 is placed in a fixed position on the underside of the loading platform 11, the swing arm 8 is inserted into the slit 12a of the cover plate 12 to fix the base plate 6 to the loading platform 11. The assembly unit 10 fixes the base plate 6 to the loading platform 11 by inserting the swing arm 8 into the slit 12a of the cover plate 12 and guiding the guide pin 8a of the swing arm 8 into the guide groove 2 of the running board 1. The swing arm 8 slides through the slit 12a of the cover plate 12 and is rotated by the cylinder 9. The structure in which the slit 12a of the cover plate 12 holds the swing arm 8 in a horizontal position and positions the guide pin 8a in the guide groove 2 of the running board 1 means that the second connecting portion 7B of the base plate 6 does not need to hold the long swing arm 8 in a horizontal position. Therefore, this structure simplifies the connection structure of the second connection portion 7B of the base plate 6 to which the swing arm 8 is connected.

[0032] The cylinder 9 has its tip connected to an intermediate connecting part 8b midway along the swing arm 8, and its rear end connected to the second connecting part 7B of the base plate 6. Both ends of the cylinder 9 are connected to the swing arm 8 and the base plate 6 so that it can rotate in a horizontal plane. The cylinder 9 extends and retracts to move the running board 1 along the drive shaft 3 via the swing arm 8. The cylinder 9 is a hydraulic cylinder or an electric cylinder. Hydraulic cylinders are connected to a hydraulic circuit (not shown) and are extended and retracted. The hydraulic circuit connects the cylinder to a hydraulic pump via a selector valve, supplying hydraulic pressure to both sides of the piston to extend and retract. Electric cylinders can be extended and retracted by rotating the motor forward and backward using a power circuit.

[0033] Furthermore, the gap adjustment mechanism 5 shown in Fig. 6 is provided with a grease-up mechanism 15 that supplies grease to the moving parts. The grease-up mechanism 15 has a supply section 15a that supplies grease, which is branched by a silicone tube 15b and connected to a grease supply nipple (not shown) fixed to each moving part. This grease-up mechanism 15 supplies pressurized grease to supply section 15a using a grease gun 15c, and can then supply grease to all moving parts via silicone tube 15b, making it easy to supply grease to a large number of moving parts. [Industrial Applicability]

[0034] The heavy-duty transport vehicle of the present invention can be suitably used as a heavy-duty transport vehicle in which a running board spacing adjustment mechanism can be simply and easily installed on the loading platform, and the swing arm and cylinder of the spacing adjustment mechanism can be fixed to the loading platform with sufficient strength so that they can be installed in a small area under the loading platform. [Explanation of symbols]

[0035] 100...Transport vehicle 1...Stepping board 1a…Square hole 2...Guide groove 3...Drive shaft 3a...Rotating arm 4...Actuator 5…Space adjustment mechanism 6...Base plate 6a...Horizontal plate section 6b...Vertical plate section 7A...First connecting part 7B...Second connecting part 8...Swing arm 8a...Guide pin 8b…Intermediate connection part 9...Cylinder 10...Assembly unit 11...Cargo bed 11a...Horizontal rib 11b...Vertical rib 12...Cover plate 12a...Slit 12b...insertion opening 13...Support plate 15...Grease mechanism 15a...supply section 15b...Silicone tube 15c...Grease gun 16...Metal plate 17...Connecting pin 20...Connection part 21...Mating recess 22...Blocking member 23...Outer frame 24...Sliding plate 25...Facing plate 25a...curved section 26...Sliding groove 27...Fixing bolt 28...Blockage block 900...Transport vehicle 901...Stepping board 903...Slide shaft 904...Cylinder 904A...Telescopic rod 905…Space adjustment mechanism 908...Swing arm 908a...Guide pin 909...Connection shaft 910...Assembly unit 911...cargo bed 912...Pivot shaft

Claims

1. a drive shaft rotatably connected to the rear end of the loading platform in a position extending in the width direction; a running board connected to the drive shaft in a non-rotating state so as to be freely movable in the axial direction; an actuator that rotates the drive shaft to tilt the running board in a vertical plane; a gap adjustment mechanism that adjusts the gap between the running boards by moving the running boards along the drive shaft in the width direction of the loading platform; Equipped with The gap adjustment mechanism is a base plate fixed to the loading platform in a position extending in the width direction; a swing arm having one end connected to the first connecting portion of the base plate so as to be rotatable in a horizontal plane and the other end connected to the running board; a cylinder having one end connected to the middle of the swing arm and the other end connected to the second connecting portion of the base plate so as to be rotatable in a horizontal plane, and which itself expands and contracts to rotate the swing arm in a horizontal plane; The assembly unit comprises: the base plate of the assembly unit is configured such that the first connecting portion and the second connecting portion are spaced apart in the width direction of the loading platform, A heavy-duty transport vehicle in which the base plate of the assembly unit is fixed to the loading platform, and the swing arm and the cylinder are arranged in fixed positions on the loading platform via the base plate.

2. The heavy-duty transport vehicle according to claim 1, the base plate includes metal plates fixed to the base plate at the first connecting portion and the second connecting portion, The vehicle for transporting heavy objects has the swing arm and the cylinder rotatably connected to the metal plate via a connecting pin.

3. 3. A heavy-duty transport vehicle according to claim 2, the base plate has a pair of metal plates at the first connecting portion and the second connecting portion, A vehicle for transporting heavy objects, in which a portion of each of the swing arm and the cylinder is disposed between the pair of metal plates and connected to each other via the connecting pin so as to be rotatable in a horizontal plane.

4. A heavy-duty transport vehicle according to any one of claims 1 to 3, The loading platform has a transverse rib extending in the width direction on its underside, The base plate is fixed to the vertical surface of the horizontal rib, thereby forming a heavy-duty transport vehicle.

5. A heavy-duty transport vehicle according to claim 4, The loading platform has a longitudinal rib extending in the vertical direction on its underside, The base plate is a heavy-duty transport vehicle having a horizontal plate portion fixed to the horizontal ribs and a vertical plate portion fixed to the vertical surfaces of the vertical ribs.

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