Dump truck

Abstract

In a dump truck (1) in which a cab (7) is disposed on a deck (5) of a vehicle body frame (2) and an engine (9) is mounted below the deck (5), maintenance steps (10l, 10r) that serve as standing positions for workers are provided on both left and right sides of the engine (9). Hatches (11l, 11r) are formed as openings in positions directly above the maintenance steps (10l, 10r) on the deck (5), and the hatches are provided with hatch covers (13l, 13r) that can be opened and closed. Ladders (15l, 15r) that allow the workers to ascend and descend are installed between the hatches (11l, 11r) and the maintenance steps (10l, 10r).

Description

Dump truck

[0001] The present invention relates to a dump truck.

[0002] For example, an extra-large dump truck used to transport crushed stone, earth and sand, etc. (hereinafter referred to as excavated material) excavated from a mine or the like has a liftable loading platform disposed at the rear of the vehicle body frame, and a driver's cab where the operator sits is disposed on a deck formed in front of the loading platform. An engine is mounted on the vehicle body frame below the deck, and the vehicle runs on power from a generator driven by the engine. This type of dump truck has a high ground clearance, making it difficult to get in and out of the driver's cab, etc. Therefore, as described in Patent Document 1, for example, a step structure consisting of stairs or a ladder has been proposed to allow the operator to get in and out of the cab between the ground and the driver's cab, etc.

[0003] Meanwhile, in addition to such a step structure, maintenance steps are provided on the body frame 2 of the dump truck. For example, as shown in Fig. 9, maintenance steps 10l, 10r are provided on both the left and right sides of the engine 9, and workers stand on these maintenance steps 10l, 10r to perform maintenance work such as inspecting and repairing the engine 9. For example, because the maintenance steps 10l, 10r are located at a height of about 3 m from the ground, ladders 51l, 51r are suspended from each of the maintenance steps 10l, 10r down to the ground, and workers on the ground can access the maintenance steps 10l, 10r via these ladders 51l, 51r.

[0004] Patent No. 5236810

[0005] However, the above-described ladders 51l, 51r have a problem of high manufacturing costs. Specifically, the engine 9 is mounted on the body frame 2, and the front wheels 3f are located on both the left and right sides of the body frame 2. For this reason, the left and right ladders 51l, 51r are disposed in a positional relationship sandwiched between the body frame 2 and the left and right front wheels 3f, respectively, and have a complex shape, as shown in Figure 9, for example, to avoid interference even when the front wheels 3f are steered to their maximum steering angle. As a result, manufacturing the ladders 51l, 51r is time-consuming, which is a factor in raising the manufacturing costs of dump trucks.

[0006] Furthermore, because the lower ends of the ladders 51l, 51r reach close to the ground so that workers on the ground can ascend and descend, there is a possibility that they may collide with rocks or other objects scattered on the ground and be damaged while the vehicle is traveling. As a countermeasure, for example, the lower portions 52 (only the left side is shown) of the ladders 51l, 51r are made of rubber, but this also creates the problem that the ladders 51l, 51r bend under the weight of the worker, making it difficult to ascend and descend.

[0007] The present invention has been made to solve these problems, and its purpose is to provide a dump truck that ensures good ladder lifting and lowering performance, prevents damage to the ladder due to collisions with obstacles while the vehicle is traveling, and further has a ladder with a simple shape that reduces manufacturing costs.

[0008] In order to achieve the above-mentioned object, the dump truck of the present invention is characterized in that a driver's cab for an operator is arranged on a deck formed on a body frame, and a power source for driving the vehicle is mounted below the deck, the dump truck being equipped with: a maintenance step provided on at least either the left or right side of the power source and functioning as a standing position for a worker maintaining the power source; a hatch that opens at a position on the deck corresponding to above the maintenance step and connects the upper and lower sides of the deck; a hatch cover that can be switched between a closed position that closes the hatch and an open position that opens the hatch; and a ladder that is installed between the hatch and the maintenance step and can be used by the worker to climb up and down.

[0009] The dump truck of the present invention ensures good ladder lifting and lowering performance, while preventing damage to the ladder due to collisions with obstacles while the vehicle is traveling.Furthermore, the ladder has a simple shape, which reduces manufacturing costs.

[0010] 1 is a perspective view showing a dump truck according to an embodiment; FIG. 2 is a front view showing a dump truck; FIG. 3 is a plan view showing the positional relationship between the maintenance step, the engine, and the front wheels; FIG. 4 is a perspective view of the left hatch cover in the closed position, as viewed from the diagonally front right; FIG. 5 is a perspective view of the left hatch cover in the open position, as viewed from the diagonally front right; FIG. 6 is a perspective view of the left hatch cover, ladder, and maintenance step, as viewed from the diagonally front right; FIG. 7 is a perspective view of the left and right hatch covers in the open position as viewed from the driver's cab; FIG. 8 is a perspective view of a conventional ladder, engine, and left front wheel, as viewed from the diagonally front left;

[0011] An embodiment of a dump truck embodying the present invention will now be described. Fig. 1 is a perspective view of the dump truck of this embodiment, and Fig. 2 is a front view of the same dump truck. The dump truck 1 is used to transport excavated material from a mine or the like, and in the following description, forward / backward, left / right, and up / down directions are expressed with reference to an operator riding in the dump truck 1.

[0012] A pair of left and right front wheels 3f is provided at the front of the body frame 2 of the dump truck 1, and two pairs of left and right rear wheels 3r are provided at the rear, and these front and rear wheels 3f, 3r are used to drive the dump truck 1. A loading platform 4 for loading excavated materials is disposed on the body frame 2, and although not shown, the rear of the loading platform 4 is connected to the body frame 2 via a hinge. The loading platform 4 rises and falls about the hinge in response to the extension and contraction of a hoist cylinder (not shown), and can be switched between a transport position shown in Figure 1 in which excavated materials are loaded and a discharge position (not shown) in which the excavated materials are discharged rearward.

[0013] A horizontal deck 5 is formed in front of the loading platform 4 of the body frame 2, handrails 6 (shown in FIGS. 4 and 5) are provided around the periphery of the deck 5, and a cab 7 for the operator is disposed on the left side of the deck 5. Because the dump truck 1 has a high minimum ground clearance and makes it difficult to get in and out of the cab 7 and the like, stairs and ladders (not shown) are provided at various locations on the body frame 2 for the operator to get in and out between the ground and the cab 7 and the like. Note that the structure of these stairs and steps is not relevant to the gist of the present invention, and therefore a detailed description thereof will be omitted.

[0014] An engine 9 (power source) is mounted on the body frame 2, which corresponds to the underside of the deck 5. Although not shown, electricity from a generator driven by the engine 9 is supplied to a traveling motor, which drives the left and right rear wheels 3r to cause the dump truck 1 to travel.

[0015] FIG. 3 is a plan view showing the relative positions of the maintenance steps, engine 9, and front wheel 3f, with the deck 5 also shown. As shown in FIGS. 2 and 3 , maintenance steps 10l, 10r are provided on both the left and right sides of the engine 9, respectively, to serve as standing positions for workers. Specifically, each maintenance step 10l, 10r is a horizontal rectangular plate, and its rear end is fixed to the body frame 2 via a bracket (not shown). Each maintenance step 10l, 10r has an upper surface large enough for a person to stand on, so that workers can inspect and repair the engine 9 while standing on the maintenance step 10l, 10r. The vertical positions of the maintenance steps 10l, 10r are set, for example, about 3 m above the ground, taking into consideration ease of performing maintenance work on the engine 9.

[0016] As described with reference to Figure 9, in conventional dump trucks, workers on the ground could access the maintenance steps 10l, 10r via ladders 51l, 51r suspended from the maintenance steps 10l, 10r. This resulted in problems such as the ladders 51l, 51r having complex shapes to prevent interference with the front wheels 3f, and the lower parts 52 of the ladders 51l, 51r being made of rubber, which made it difficult to ascend and descend. In consideration of these problems, the present invention changes the access route to the maintenance steps 10l, 10r, the details of which are described below.

[0017] Fig. 4 is a perspective view of the left hatch cover in the closed position as seen from diagonally forward right, Fig. 5 is a perspective view of the left hatch cover in the open position as seen from diagonally forward right, and Fig. 6 is a perspective view of the left hatch cover in the open position as seen from diagonally rear right. An openable door 7a is provided on the right side of the cab 7, and an operator can get into the cab 7 through this door 7a. In addition, windows 7b, 7c are provided on the front and both left and right sides of the cab 7 (the left side is not shown), and the operator can drive and operate the dump truck 1 while viewing the surroundings through the windows 7b, 7c.

[0018] Hatches 11l and 11r are formed on the deck 5 as access openings at positions directly above the left and right maintenance steps 10l and 10r, respectively, and the upper and lower sides of the deck 5 are connected to each other via each hatch 11l and 11r. Each hatch 11l and 11r is rectangular and large enough for a person to pass through. The configuration for accessing the maintenance steps 10l and 10r via these hatches 11l and 11r will be described below, but because they have the same configuration, the left hatch 11l will be described as a representative example.

[0019] A square plate-shaped hatch cover 13l is connected to the front edge (corresponding to the "periphery" of the present invention) of the hatch 11l via a hinge 12, and the hatch cover 13l is rotatable about the hinge 12 between a closed position in which the hatch 11l is closed as shown in FIG. 4 and an open position in which the hatch 11l is open as shown in FIG. 5. The left side of the hatch 11l and the left side of the hatch cover 13l are connected via a gas spring 14 (corresponding to the "rotation restricting member" of the present invention). The hatch cover 13l, which has been rotated to the open position, is restricted in rotation by the gas spring 14, and is maintained in a position in which its rear edge is flipped up as shown in FIG. 6. The hatch cover 13l is opened and closed by gripping the hatch cover 13l itself, and is maintained in the closed position while the dump truck 1 is in operation.

[0020] Figure 7 is a perspective view of the left hatch cover 13l, ladder, and maintenance step 10l, viewed from the front right. As shown in Figures 2, 5, and 7, a ladder 15l is installed between the hatch 11l and the maintenance step 10l. As will be described in detail later, the ladder 15l functions as an access route to the maintenance step 10l, replacing the conventional ladders 51l and 51r shown in Figure 9.

[0021] The conventional ladders 51l, 51r for accessing the maintenance steps 10l, 10r from the ground had to be disposed on both the left and right sides of the body frame 2, resulting in a complex shape to prevent interference with the front wheels 3f. In contrast, the ladder 15l of this embodiment, which is accessed from the deck 5, can be disposed within the left and right width of the body frame 2 as shown in Figure 2, and as a result does not interfere with the front wheels 3f, so there is no need for a complex shape to prevent interference. Furthermore, the conventional ladders 51l, 51r had lower parts 52 made of rubber in anticipation of collisions with obstacles on the ground, but the ladder 15l of this embodiment does not collide with obstacles, so there is no need for a rubber lower part.

[0022] In consideration of the above, the ladder 15l of this embodiment is entirely made of welded steel pipes (corresponding to the "metal material" in the present invention) and has high rigidity and a simple, typical ladder-like shape. Specifically, as shown in FIGS. 5 to 7 , the ladder 15l is configured by a pair of vertically extending steel pipes serving as supports 16 (corresponding to the "metal material" in the present invention) and a plurality of horizontally extending steel pipes serving as steps 17 (corresponding to the "metal material" in the present invention), with the left and right supports 16 connected to each other by the steps 17. The ladder 15l is disposed vertically and facing left and right. The upper end of the ladder 15l is fixed to the left side of the hatch 11l (corresponding to the "side opposite the power source" in the present invention) via a bracket 18, and the lower end of the ladder 15l is fixed to the left side of the upper surface of the maintenance step 10l (corresponding to the "side opposite the power source" in the present invention) via a bracket 19.

[0023] It is not necessary to position the ladder 15l completely within the left-right width of the body frame 2, and the ladder 15l may protrude leftward from the body frame 2 to the extent that it does not interfere with the front wheel 3f. The above is the configuration related to the left-side hatch 11l, hatch cover 13l, and ladder 15l, and although a redundant explanation will not be given, the right-side hatch 11r, hatch cover 13r, and ladder 15r have the same symmetrical configuration.

[0024] Fig. 8 is a perspective view of the left and right hatch covers 13l, 13r in the open position as viewed from the cab 7. The open / closed states of the left and right hatch covers 13l, 13r can be recognized by the operator seated in the cab 7. More specifically, the area of ​​the window 7c on the right side of the cab 7 is set so that when the left and right hatch covers 13l, 13r are rotated to the open position as shown in Fig. 8, in other words, when the trailing edges are raised, the operator seated in the cab can see any part of each hatch cover 13l, 13r.

[0025] Next, the effects of the dump truck 1 configured as described above will be explained. For example, when performing maintenance work on the engine 9 while standing on the left maintenance step 10l, the worker first switches the left hatch cover 13l to the open position on the deck 5, and then, as shown in Figure 2, descends from the upwardly opening hatch 11l to the maintenance step 10l via the ladder 15l. At this time, the worker may be holding tools, parts, etc., but because the ladder 15l, which is made entirely of welded steel pipes as described above, has high rigidity and can support the worker's weight, the worker can easily descend to the maintenance step 10l via the ladder 15l.

[0026] Upon completing maintenance work on the engine 9, the worker climbs the ladder 15l from the maintenance step 10l, passes through the hatch 11l, and returns to the deck 5, and then switches the hatch cover 13l to the closed position. Even at this time, the ladder 15l has high rigidity and can support the weight of the worker, allowing the worker to easily return to the deck 5 via the ladder 15l. Because the ladder 15l has good ascending and descending ability in this way, the worker can easily access the maintenance step 10l, thereby reducing the effort required for maintenance work.

[0027] In addition, the shorter overall length of the ladder 15l compared to the conventional technology shown in FIG. 9 also contributes to reducing the effort required for maintenance work. In the specifications of the dump truck 1 of this embodiment, the height from the ground to the maintenance step 10l is 3 m, while the height from the maintenance step 10l to the deck 5 is only approximately 1.7 m. Therefore, while the conventional technology requires the ladder 51l to ascend and descend a distance of approximately 3 m from the ground, this embodiment requires only ascending and descending a distance of approximately 1.7 m from the deck 5 using the ladder 15l. As a result, the labor required by the worker to ascend and descend the ladder 15l can be further reduced. Furthermore, the short distance between the assistant on the deck 5 and the worker on the maintenance step 10l makes it easy to hand over tools, parts, and the like. These points also contribute to reducing the effort required for maintenance work.

[0028] This embodiment also contributes to the safety of workers standing on the maintenance step 10l. That is, as can be seen from FIG. 2 , although the engine 9 is located to the right of the left maintenance step 10l, a large space about 3 m high leading to the ground is formed between the left side of the maintenance step 10l and the front wheel 3f. Therefore, a worker standing on the maintenance step 10l may become nervous imagining falling to the ground and be unable to concentrate on his / her maintenance work. In this embodiment, the ladder 15l is located on the left side of the maintenance step 10l, which functions as a handrail to prevent the worker from falling, improving safety and allowing the worker to concentrate on his / her maintenance work.

[0029] The ladder 15l, which provides these various effects, has a simple, typical ladder-like shape and can be easily manufactured without the hassle of the prior art shown in Figure 9. Furthermore, since the overall length is shorter than that of the prior art, it is possible to reduce material costs. As a result, the ladder 15l can be manufactured inexpensively, which in turn reduces the manufacturing cost of the dump truck 1.

[0030] Although the above is an effect achieved by the left ladder 15l, the same effect can be achieved by the right ladder 15r.

[0031] Meanwhile, there may be cases where an operator is in the cab 7 while a worker is performing maintenance on the engine 9. For example, if the operator inadvertently starts the engine 9, the operator may be surprised. In this embodiment, the operator can visually check the hatch covers 13l, 13r, which are kept in the open position during maintenance work, through the window 7c. Therefore, when the operator visually checks either the left or right hatch cover 13l, 13r, the operator can recognize that the hatches 11l, 11r are kept in the open position, i.e., that the worker is performing maintenance work on the maintenance steps 10l, 10r. Therefore, inadvertent operations such as starting the engine 9 are prevented, which greatly contributes to the smooth execution of maintenance work.

[0032] This concludes the description of the embodiment, but the aspects of the present invention are not limited to this embodiment. For example, while the dump truck 1 of the above embodiment has an engine 9 mounted on the body frame 2 as a power source, there are also dump trucks that have a traction battery mounted on the body frame 2 as a power source. In this type of dump truck, power is supplied directly from the traction battery to the traction motor to drive the dump truck, but in this case, maintenance steps 10l and 10r are also provided for inspecting and repairing the traction battery. Therefore, the present invention may be applied to such dump trucks, and although a redundant description will not be provided, the same effects as those of the above embodiment can be achieved.

[0033] In addition, in the above embodiment, maintenance steps 10l, 10r are provided on both the left and right sides of the engine 9, and hatches 11l, 11r, hatch covers 13l, 13r, and ladders 15l, 15r are provided corresponding to each maintenance step 10l, 10r, respectively. However, these components do not necessarily have to be provided on both the left and right sides, and may be provided on only one of the left and right sides.

[0034] In addition, in the above embodiment, the hatch covers 13l and 13r can be opened and closed around the hinge 12, but this is not limited to this, and for example, sliding hatch covers may also be used.

[0035] In addition, in the above embodiment, the ladders 15l and 15r are arranged vertically and facing in the left-right direction, but this is not limited to this. For example, the ladders 15l and 15r may be arranged in a slightly inclined position, or in a position facing in the front-to-rear direction.

[0036] REFERENCE SIGNS LIST 1 Dump truck 2 Vehicle body frame 5 Deck 7 Cab 7c Window 9 Engine (power source) 10l, 10r Maintenance step 11l, 11r Hatch 12 Hinge 13l, 13r Hatch cover 14 Gas spring (rotation restriction member) 15l, 15r Ladder 16 Support (metal material) 17 Step (metal material)

Claims

1. A dump truck having a driver's cab for an operator disposed on a deck formed on a body frame, and a power source for propelling the vehicle mounted below the deck, the dump truck comprising: a maintenance step provided on at least either the left or right side of the power source and functioning as a standing position for an operator maintaining the power source; a hatch opening formed on the deck at a position corresponding to above the maintenance step and communicating the upper and lower sides of the deck; a hatch cover switchable between a closed position that closes the hatch and an open position that opens the hatch; and a ladder installed between the hatch and the maintenance step and allowing the operator to ascend and descend.

2. The dump truck described in claim 1, characterized in that the upper end of the ladder is arranged on the opposite side of the hatch from the power source in the left-right direction, and the lower end of the ladder is arranged on the maintenance step on the opposite side of the power source in the left-right direction.

3. The dump truck according to claim 1, characterized in that the hatch cover is connected to the periphery of the hatch via a hinge so as to be able to open and close, and in the open position, its rotation is restricted by a rotation restricting member so that it is kept in a flipped-up position, and the driver's cab is provided with a window that allows an operator seated in the driver's seat to view the hatch cover that has been switched to the open position.

4. The dump truck according to claim 1, wherein the ladder is disposed within the left-right width of the body frame.

5. The dump truck according to claim 1, wherein the ladder is made entirely of metal.

6. The dump truck according to claim 1, characterized in that the ladder is shaped like a ladder, with a pair of metal members extending vertically as supports and multiple metal members extending horizontally as steps.

Images