JPH025853B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is designed to maintain the stability of the running vehicle body on various terrain such as flat land, slopes, mountains, uneven terrain, etc.
This invention relates to a groove excavator that can continuously and freely excavate any groove such as a curved groove or a zigzag groove.

Conventionally, this type of trench excavator has been equipped with a chain ladder type, rotary bucket type, etc. excavating device on the traveling vehicle body, but due to the structure of the excavating device itself, all of these machines can only excavate straight grooves, and cannot excavate curved grooves etc. was difficult. In particular, when excavating so-called zigzag grooves that are bent at acute angles (or obtuse angles), it is difficult to change direction at the bend.
Once the excavation work is interrupted, the excavation equipment is pulled out from the trench, the trench excavation machine is turned in a predetermined direction, the excavation equipment is used to dig into the ground again until it reaches the predetermined depth, and then the trench excavation machine is moved forward. It was necessary to repeat the same work procedure. For this reason, it is not suitable for excavating grooves along contour lines on slopes of mountains, hills, etc., curved grooves surrounding or bypassing trees, rocks, etc., orthogonal grooves for building root cutting work, etc., and other turning grooves. It has the disadvantage of lacking in sex.

The present invention has been made in view of the above-mentioned points, and its first purpose is to connect an excavation device with a traveling vehicle body,
a traveling device disposed on both sides of the traveling vehicle; and a traveling device disposed approximately at the center in the longitudinal direction of the traveling vehicle so as to vertically penetrate the traveling vehicle in the vicinity of the center of gravity, excavating the ground directly under the central portion of the vehicle; An excavation device that can be raised and lowered to guide the earth and sand above the traveling vehicle body; and an excavation device that is disposed at the center of the upper surface of the traveling vehicle body so as to be movable vertically and horizontally, and that receives the earth and sand excavated by the excavation device, and the traveling vehicle body an earth remover that transports and removes earth to the side; a drive source that raises and lowers this earth remover according to the trench excavation depth; and a drive source that moves the earth earth remover in the left and right direction;
When not excavating, it is configured with a drive source stored in the center of the vehicle body, making it possible to change the direction of the traveling vehicle body on the spot.In addition, it can safely and continuously cut not only straight grooves but also curved grooves with small curvatures and zigzag grooves. The objective is to provide a trench excavator that can be used to excavate.

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

Fig. 1 is a side sectional view showing an embodiment of a trench excavator according to the present invention, Fig. 2 is a sectional view taken along line A-A in Fig. 1, and Fig. 3 is a partially cutaway view of the main parts of the excavator. FIG. 4 is a sectional view taken along the line B--B in FIG. 3, and FIG. 5 is a sectional view taken along the line C--C in FIG. 1. In FIG. 1, the trench excavator, which is designated as a whole by reference numeral 1, is equipped with a running body 2 that extends long in the front-rear direction and has an opening 3 (see FIG. 3) in the center. Various devices including an engine 4, a hydraulic power device 5 driven by the engine 4 to generate hydraulic pressure, and a hydraulic control device 6 that controls the hydraulic pressure from the hydraulic power device 5 to operate various hydraulic devices described later. is installed. A driver's cab 8 is provided on the upper surface of the front end of the traveling vehicle body 2 in which a worker 7 rides and operates the trench excavator 1 itself and various devices and mechanisms described later. A pair of traveling devices 11A and 11B (see FIG. 3), which will be described later, are disposed on both sides and extend over almost the entire length of the traveling vehicle body 2. These traveling devices 11A and 11B include a pair of front and rear variable suspension devices 10A and 10B that are arranged on both sides of the traveling vehicle body 2 so that they can be raised and lowered independently.
It is held in common by 10C and 10D.

The variable suspension devices 10A, 10B, 10C, 1
Since 0D has the same configuration on the left, right, front, and back,
One of them, for example, the front left suspension system 10A when viewed from the front of the vehicle body, will be described in detail with reference to FIG. A slide leg 14 having a substantially square shape and extending in the vertical direction and fitting into the guide block 13 so as to be slidable in the vertical direction.
and a hydraulic cylinder 15 for moving the slide leg 14 up and down. The cylinder portion of the hydraulic cylinder 15 is fixed to the traveling vehicle body 2, and the rod portion is connected to the slide leg 14. Therefore, when the rod part expands and contracts by driving the hydraulic cylinder 15, the slide leg 14 slides in the vertical direction along the guide block 13, thereby arbitrarily adjusting the height of the front end of the traveling device 11A. change. This height control is performed by adjusting the pressure oil supplied to the hydraulic cylinder 15, and each variable suspension system 10 is adjusted according to the traveling terrain or excavation state.
A, 10B, 10C, 10D slide legs 14,
14b, 14c, 14d are hydraulic cylinders 15, 1
5b, 15c, 15d at the same time on the left and right front and back, or all slide legs 14, 14b,
By operating 14c and 14d simultaneously,
The heights of the left and right traveling devices 11A, 11B are changed to maintain the left and right slope of the traveling vehicle body 2 substantially horizontally, or the vehicle height is changed according to the working terrain. In this case, each hydraulic cylinder 15, 15b, 15c, 1
The expansion/contraction control 5d is performed automatically or manually via the hydraulic control device 6 based on a signal from a tilt detector (not shown) attached to the traveling vehicle body 2.

Since the left and right integrated traveling devices 11A and 11B have the same structure on the left and right, only one of them 11A will be described in detail based mainly on FIGS. 3 and 4. It includes an extending frame 20. This frame 20
The pair of front and rear variable suspension devices 10A and 10B are arranged on the side of the vehicle body on the same side as the frame 20.
is connected to and held by the frame 20.
The outer ends of a pair of front and rear arms 21A, 21B are connected to the inner surface of the arm. The inner end of the front arm 21A is attached to a bearing 31 (the first
(see figure). Moreover, one end of the intermediate portion of this arm 21A is rotatably connected to the other end of a hydraulic cylinder 24A, which is rotatably connected to the heightwise intermediate portion of the slide leg 14 of the variable suspension device 10A. On the other hand, the inner end of the rear arm 21B is connected to the rear variable suspension device 1.
It is rotatably connected to the lower end surface of the guide block 13b constituting 0B via a bearing 22. The intermediate portion of the arm 21B is connected to the other end of a hydraulic cylinder 24B, which is rotatably connected to the intermediate portion in the height direction of the slide leg 14b, which is slidably fitted and held in the guide block 13b. connected.

A horizontal shaft 27 is rotatably disposed on the front end surface of the frame 20 via a bracket 26, and a guide wheel 28 is provided at each end of the shaft 27.
A and 28B are fixed. On the other hand, frame 2
A hydraulic motor 29 with a reduction gear is disposed on the rear end surface of the motor 0 with a bracket 30 interposed therebetween. A pair of starting wheels 36A and 36B made of sprockets are fixed to the output shaft 35 of the hydraulic motor 29. A plurality of lower wheels 37 are rotatably disposed at the center of the frame 20, that is, on both sides between the pair of arms 21A and 21B via brackets 38. The pair of guide wheels 28A, 2
A crawler belt 40 is stretched between 8B and covers the upper and lower surfaces of the frame 20. Grousers 41 are integrally provided on the outer peripheral surface of this crawler belt 40 over the entire circumference, while the respective driving wheels 36A, 3 are provided on the inner peripheral surface.
Two drive chains 44A, 44B corresponding to 6B
Two protrusions 46 are provided around the entire circumference and prevent the crawler belt 40 from coming off (movement in the left and right direction).
A and 46B are integrally provided in a protruding manner. The drive chains 44A, 44B mesh with the teeth of the pair of starting wheels 36A, 36B, respectively, at the bent portion on the rear end side of the crawler track 40, thereby causing the hydraulic motor 2
The rotation of the output shaft 35 due to the drive of the starting wheel 3
6A, 36B and drive chains 44A, 44B to the crawler belt 40, causing the crawler belt 40 to rotate. Therefore, when the tracks 40 of the pair of left and right traveling devices 11A, 11B are rotated in the same direction at the same speed, the traveling vehicle body 2 moves forward or backward in a straight line, and when turning left and right, the tracks 40 of the left and right traveling devices 11A, 11B rotate. This is done by changing the rotational speed of the hydraulic motor 29 of 11B and braking the crawler belt 40 on the inside of the curve. That is, the left and right traveling devices 11A, 11B are equipped with hydraulic motors 29 that are driven independently, and are driven and controlled independently or in conjunction with each other, thereby enabling the traveling vehicle body 2 to move forward and backward and turn left and right. It is something.

In this case, when traveling on flat ground, the left and right traveling devices 11A and 11B are set at the same height, and the vehicle body 2 travels while maintaining ground clearance and horizontality.

Further, as described above, each traveling device 11A, 11B is connected and held to a pair of front and rear variable suspension devices 10A, 10B and 10C, 10D, and a pair of hydraulic cylinders 24A, 24B and 24C, 24D.
(See Figure 3), which enables stable running on steep slopes. That is, for example, the second
As shown in the figure, when traversing on a slope descending to the right, a pair of front and rear variable suspension systems 10A on the mountain side,
10B and raise the traveling device 11A. Simultaneously, the pair of front and rear hydraulic cylinders 24A, 24B are retracted to rotate the traveling device 11A clockwise in FIG. 2 by a predetermined angle around the inner ends of the arms 21A, 21B. By doing so, the entire lower surface of the crawler track 40 of the traveling device 11A can be brought into contact with the slope, and on the contrary, the pair of front and rear variable suspension devices 10C, 1 on the valley side can be brought into contact with the slope.
0D is extended to lower the traveling device 11B, and at the same time, the pair of front and rear hydraulic cylinders 24C and 24D are extended to rotate the traveling device 11B to the valley side by the same angle as the traveling device 11A on the mountain side.
Since the lower surface of the crawler track 40 is also in complete contact with the slope, good ground contact pressure can be ensured, so running performance is not degraded. Moreover, collapse of the ground surface and skidding of the traveling vehicle body 2 itself are prevented. Furthermore, due to the vertical movement of the traveling devices 11A and 11B, the traveling vehicle body 2
Since it remains horizontal even on steep slopes, it can freely traverse steep slopes.

The central part of the traveling vehicle body 2, that is, the trench excavator 1
A chain ladder excavator 60 is disposed at the center of gravity of the excavator 60 so as to be movable up and down, thereby making it possible to excavate various types of grooves such as straight grooves, curved grooves, and folded grooves. The construction of the excavation device 60 will be described in more detail with reference to FIGS. 1 to 3 and 5. A pair of convex guides 64A and 64B are provided at both ends of the central portion of the traveling vehicle body 2, respectively, facing each other in the front and rear. ,64C and 6
4D is provided extending upward, and slide blocks 61A and 61B are fitted between these convex guides 64A and 64B and between 64C and 64D so as to be slidable in the vertical direction. A horizontal frame 62 is provided between the pair of slide blocks 61A and 61B.
is supported, and the upper end portion of a vertical frame 63 extending in the vertical direction is firmly fixed to the center portion of the front side of the horizontal frame 62. The vertical frame 63 is provided so as to pass through the opening 3 of the traveling vehicle body 2, and has sprockets 66, 6 at its upper and lower ends, respectively.
7 is rotatably disposed via brackets 68, 69 and shafts 70, 71. A horizontal bracket 75 extending rearward is disposed at the center of the back of the horizontal frame 62, and a fleece sprocket 76 is connected to a shaft 77 at the tip of the bracket 75.
It is rotatably arranged through the. The sprockets 66, 67 and the fleece sprocket 76
A chain 79 as an endless rotating body is stretched over the chain 79, and small rollers 80 are provided at both ends of the connecting pin portion of the chain 79, as shown in FIG. These small rollers 80 roll along the front surface of a curved bracket 81 provided on the rear surface of the approximately central portion of the vertical frame 63, thereby moving the chain 79 at the lower end of the excavating device 60, that is, at the excavating section 100. It is made to run approximately parallel to the front and rear surfaces of the vertical frame 63. A large number of cutters 85 are arranged on this chain 79 at predetermined intervals.

Each of the cutters 85 has a substantially C-shaped planar shape and a substantially L-shaped cross-section, thereby integrally having an auxiliary rib 86. In this case, the front portion of the cutter 85 extending in the left-right direction constitutes a front excavation cutter 85A (see FIG. 5) that excavates the front surface of the groove 101, while the front portion of the cutter 85 extending in the left-right direction constitutes a front excavation cutter 85A (see FIG. 5). Both side surfaces extending rearward are side excavation cutters 8 for excavating the side surfaces of the groove 101.
Configures 5B and 85C. That is, the cutter 85 according to the present invention is composed of a front excavation cutter 85A and side excavation cutters 85B and 85C that excavate the front and both side surfaces of the groove 101 at the same time. As a result, the cutter located on the rear side of the vertical frame 63 runs along a trajectory close to the cutter on the front side. For this reason, the excavation section 100
In this case, as shown in Fig. 5, the front and rear cutters 85 are
The interval D is set narrowly. This is to enable smooth and reliable side excavation of the groove 101 and vertical movement of the cutters 85 when excavating curved grooves, zigzag grooves, etc., and as long as the cutters 85 do not interfere with each other. set to a value.

Note that the cutter 85 is shown in which the excavation cutter 85A and the side excavation cutters 85B, 85C are provided in one piece, but the cutter 85 is not limited to this, and may be a split structure front excavation cutter 85A and side excavation cutters 85B, 85.
C may be arranged so as to be shifted in the running direction of the chain 79. Further, the cutter 85 is not necessarily in a substantially C-shape, but may be in any suitable shape such as a semicircle or an ellipse. Desirably, the cross-sectional shape of the excavation portion 100 is substantially circular, and the cross-sectional shape of the cutter 85 is substantially the same as that of a straight groove. Any material may be used as long as it enables excavation of a curved groove having a groove width.

The movement of the chain 79 is controlled by a hydraulic motor 90 (first
(see Figures 1 and 2).
That is, a sprocket 91 is fixed to an output shaft 90A of this hydraulic motor 90, and a sprocket 93 is fixed to one end of a shaft 92 rotatably disposed on the slide block 61A. Chain 94 is stretched,
Further, a chain 98 is tensioned between another sprocket 95 fixed to the other end of the shaft 92 and a drive sprocket 97 fixed to a shaft 70 disposed at the upper end of the vertical frame 63 via a bracket 68. It is suspended. Therefore, the hydraulic motor 9
0 is driven, its rotation is caused by the output shaft 90A - sprocket 91 - chain 94 - sprocket 93 -
It is transmitted to the chain 79 via the shaft 92 - sprocket 95 - chain 98 - drive sprocket 97 - sprocket 66, and moves the cutter 85 in the direction of the arrow in FIG. On the back side, the movement is activated from the top to the bottom. Then, when the excavator 60 is gradually lowered by the excavator up/down device 110, the trench 101 is excavated by the excavator 100.

The excavator lifting device 110 includes a hydraulic motor 112 with a reduction gear, as shown in FIGS. 1 to 3. This hydraulic motor 112 is connected to the convex guide 64.
Two output shafts 1 are fixedly arranged at the center of the upper surface of the mounting plate 111 that is horizontally suspended between the upper end surfaces of A, 64B, 64C, and 64D, and are rotated in opposite directions at the same rotational speed.
13A and 113B, and bevel gears 114A and 114B are fixed to the respective shaft ends thereof. A pair of left and right bearings 115A, 115B are fixed to the upper surface of the mounting plate 111, and the shafts 116, 1
17 are rotatably supported. Each axis 1
16 and 117 extend in the longitudinal direction of the vehicle body 2 so as to be perpendicular to the output shafts 113A and 113B, and bevel gears 118A and 117 are provided at both shaft ends, respectively.
8B, 119A and 119B are fixed. The front bevel gear 11 is fixed to the shaft 116.
8A is screwed into a bevel gear 121 fixed to the upper end of the feed screw 120, and a rear bevel gear 118B is meshed with the bevel gear 114A fixed to the one output shaft 113A. The feed screw 120
extends long in the vertical direction, and the upper and lower ends thereof are connected to the mounting plate 1.
11 and the traveling vehicle body 2 to be rotatably supported,
On the way, the lower slide block 61A in Figure 3
are screwed together. In other words, a threaded hole (not shown) is formed through the slide block 61A, and the feed screw 120 is screwed into this threaded hole. Similarly, the slide block 61B on the upper side in FIG. 3 also has a screw hole (not shown) into which another feed screw 124 is screwed. The upper and lower ends of this feed screw 124 are rotatably supported by the mounting plate 111 and the traveling vehicle body 2, and the upper end thereof has a bevel gear 125 ( (see Figure 2) is fixed. On the other hand, the bevel gear 119B fixed to the rear end of the shaft 117 is fixed to the other output shaft 113B. The bevel gear 11
It meshes with 4B. In this case, both feed screws 12
0 and 124 are configured to be rotated in the same direction and at the same rotation speed by the drive of the hydraulic motor 112, thereby raising or lowering the pair of slide blocks 61A and 61B simultaneously. Therefore, these slide blocks 61
When A and 61B descend, the above-mentioned excavation device 80 also descends, making it possible to excavate the groove 101, and the excavation depth at this time is determined by the hydraulic motor 1.
Adjustment is possible by controlling the amount of descent of the slide blocks 61A, 61B by the slide block 12.

A belt conveyor type earth removal machine 130 is further disposed in the center of the traveling vehicle body 2. This earth remover 130 is located in front of the excavation device 80, and is configured to be moved vertically and horizontally. In other words, the earth removal machine 13
0 has a vertical frame 140 erected at the center of the upper surface of the vehicle body 2, and a square-shaped protrusion 141 (see FIG. 3) is integrally protruded from the back side of the vertical frame 140. This protrusion body 141 has a dovetail groove 14.
A slide block 144 having a vertical frame 140 is fitted so as to be vertically movable. I try to let them do it. Further, on the back side of the slide block 144, a horizontal slide frame 1 is provided.
47 (see FIG. 1) is disposed so as to be movable in the left-right direction by fitting between the dovetail groove 149 and the square-shaped protrusion 148. This horizontal slide frame 147 extends long in the left-right direction, and the front surface of the conveyor frame 150 is fixed to the back side thereof. This conveyor frame 150 is formed in a substantially U-shape and has approximately the same length as the horizontal slide frame 147, and a belt 151 is disposed inside the conveyor frame 150.
This conveyor 151 is the conveyor frame 15
Pulleys 152 and 1 disposed at both ends of the
53 and integral idler pulleys 154a and 154b (see FIG. 2) disposed at the intermediate portion. A hydraulic motor 155 (see FIG. 3) for driving a belt is disposed at one end of the horizontal slide frame 147, and the output shaft of this motor 155 and the pulley 152 are directly connected. Therefore, when the drive motor 155 is driven, the belt 151 is rotated clockwise or counterclockwise in FIG. 2. Therefore, the excavated earth and sand thrown up by the excavation device 60 is thrown up by the belt 1.
51, it is transported to the side of the traveling vehicle body 2 and disposed of.

Further, one end of a hydraulic cylinder 160 is fixed to the slide block 144, and the other end of this hydraulic cylinder 160 is fixed to one end of the horizontal slide frame 147. The hydraulic cylinder 160 is used to selectively move the horizontal slide frame 147 to the left or right according to the topography of the excavation, and when operated in the extension direction, the belt 151 is moved to the traveling vehicle body 2 as shown in FIG. When operated in the shortening direction, it can be made to protrude to the left of the vehicle body as shown by the chain line 165 in FIG. 2, and it is stored in the center of the vehicle body except when excavating. The belt indicated by the chain line 165 in FIG. 2 is shown pushed up to the uppermost position by the aforementioned hydraulic cylinder 145. In other words, the belt 151 is used to adjust the topography of the excavation and the aforementioned variable suspension devices 10A, 10.
The hydraulic cylinders 145, 160 set and hold the soil at the optimum position depending on the state of the soil B, 10C, and 10D, thereby effectively discharging soil.

Thus, trench excavator 1 having such a configuration
According to the invention, it is possible to continuously and freely excavate various types of grooves such as straight grooves, curved grooves, and zigzag grooves. That is, if the traveling speeds of the left and right traveling devices 11A and 11B are the same, the vehicle will travel straight, and if a speed difference is given to the left and right traveling devices 11A and 11B, it will slowly turn to the left or right, and further, one of the traveling devices will travel straight. If you stop it, you can make a sharp turn, and the left and right traveling devices 11
If A and 11B are reversed at a constant speed, they will turn on the spot with the center of the traveling vehicle body 2 as the turning center, so that a desired straight groove, curved groove, zigzag groove, etc. can be excavated. In this case, the traveling vehicle body 2 is approximately in the center,
In other words, since it turns around the excavation device 60, the turning radius is minimum, and since the front cutter and the rear cutter in the excavation section 100 are placed close to each other, trench excavation can be carried out continuously without temporary interruption. It can be done quickly and efficiently.

That is, when the front side cutter and the rear side cutter in the excavation part 100 are separated and the distance D shown in FIG. In this case, the excavating unit 100 cannot excavate the groove side wall by the distance D, so it is necessary to pull out the excavating device 60 from the groove, turn the traveling vehicle body 2, and then insert the excavating device 60 into the groove again. However, if the distance D is set small as in the present invention, it is possible to eliminate the portion of the trench side wall that cannot be excavated due to this, so it is possible to continuously form turn-back trenches, zigzag trenches, etc. without temporarily interrupting trench excavation. It is something that can be done. In addition, since the excavating device 60 is simply moved up and down and does not have a structure in which it is supported by a boom or the like and rotated, the overall structure is simple and can be manufactured at low cost, and it also prevents the traveling vehicle body 2 from skidding on steep slopes. do. That is, in trench excavation on a steep slope, as shown in FIG.
0 is located near the center of gravity of the traveling vehicle body 2, and its valley side surface is pressed against the valley side surface of the groove 101, so that it acts as a resistor to prevent the vehicle body itself from skidding.

Furthermore, when excavating trenches on steep slopes, the mounting heights of the left and right traveling devices 11A and 11B can be changed and tilted along the slope, ensuring good ground pressure and keeping the traveling vehicle body 2 almost horizontal. obtain. Therefore, it has excellent maneuverability, safety and running performance, and enables excavation of vertical trenches.

In addition, an excavation device 60 is installed approximately in the center of the traveling vehicle body 2.
Since it is installed in the front end (or rear end) of the traveling vehicle body 2, it is also possible to attach the well-known backhoe 170, shovel, dozer, etc. shown by the chain line in Figure 1 in parallel, and in this way, the excavation By adding various attachments depending on the soil quality of the ground, the performance of the trench excavator can be improved, and the work itself can be performed effectively and economically.

In addition, in the above embodiment, the variable suspension devices 10A, 10
Traveling devices 11A, 1 via B, 10C, 10D
1B is installed on the traveling vehicle body 2 so as to be movable up and down, but the present invention is not limited to this, and the present invention is not limited to this, but the present invention is not limited to this, and when the vehicle is used for running on flat ground, the traveling device 11A, 1B is directly installed without using a variable suspension device. 11B may be attached to the traveling vehicle body 2.

As explained above, the trench excavating device according to the present invention is configured such that the excavating device is mounted near the center of gravity in the approximate center of the traveling vehicle body, so that the traveling vehicle body can be turned on the spot with the minimum turning radius. Therefore, it is easy to change direction in narrow spaces, and curved grooves with a small radius of curvature can be excavated continuously and freely.Furthermore, if the excavator is mounted near the center of gravity of the vehicle body, it is easy to change direction on steep slopes. It has great effects, such as preventing the vehicle body from skidding during excavation and improving work safety.

[Brief explanation of drawings]

Fig. 1 is a side sectional view showing an embodiment of a trench excavator according to the present invention, Fig. 2 is a sectional view taken along line A-A in Fig. 1, and Fig. 3 is a partially cutaway view of the main parts of the excavator. FIG. 4 is a sectional view taken along the line B--B in FIG. 3, and FIG. 5 is a sectional view taken along the line C--C in FIG. 1. 1... trench excavator, 2... traveling vehicle body, 11A, 1
1B...Traveling equipment, 60...Drilling equipment, 85...
Katsuta, 85A...Front excavation cutter, 85B,
85C... Cutter for side excavation, 100... Excavation part.

Claims (1)

[Claims] 1 A traveling vehicle body, a traveling device disposed on both sides of the traveling vehicle body, and a traveling device located approximately at the center in the longitudinal direction of the traveling vehicle body and extending vertically through the traveling vehicle body in the vicinity of the center of gravity and directly below the central portion of the vehicle body. a movable excavation device that excavates the ground and guides the earth and sand above the traveling vehicle body; an earth remover that receives the earth and sand and transports it to the side of the traveling vehicle body, a drive source that moves the earth remover up and down according to the trench excavation depth, and a drive source that moves the earth remover in the left and right direction and removes the earth without digging. A trench excavator characterized by being equipped with a drive source that is sometimes stored in the center of the vehicle body.