JPWO2019026830A1 - Asphalt finisher - Google Patents

Abstract

The asphalt finisher (100) according to the embodiment of the present invention includes at least two of a plurality of devices mounted on at least one of a tractor (1), a screed (3), and a tractor (1) and a screed (3). It is provided with a wireless communication system configured so that wireless communication is performed between the two. The equipment mounted on the tractor (1) includes at least one of the controller (50) and the operation panel (51), and the equipment mounted on the screed (3) includes the rear controller (52) and the switch box ( 53), includes at least one of a sensor, a screed controller, and a vibration power generator as a power supply device (60A).

Description

This disclosure relates to an asphalt finisher.

Conventionally, asphalt finishers in which switch boxes (screed operation boxes) are attached to both ends of the screed are known (see Patent Documents 1 and 2).
Usually, the switch box is connected to the battery mounted on the tractor via a power cable, and is connected to the control device mounted on the tractor via a communication cable.

Japanese Unexamined Patent Publication No. 2014-47568 Japanese Unexamined Patent Publication No. 2016-79570

However, since the power cable and the communication cable are configured so that the screed can be expanded and contracted in the vehicle width direction, there is a risk of damage when the screed is expanded and contracted. It can also be damaged by the heat of the pavement between the tractor and the screed. If the power cable or communication cable is damaged, the cooperation between the device mounted on the tractor and the device mounted on the screed may be cut off.

In view of the above, it is desirable to provide an asphalt finisher that more stably links the equipment mounted on the tractor and the equipment mounted on the screed.

The asphalt finisher according to the embodiment of the present invention is configured to perform wireless communication between a tractor, a screed, and at least two of a plurality of devices mounted on at least one of the tractor and the screed. It is equipped with a wireless communication system.

By the above-mentioned means, an asphalt finisher that more stably links the equipment mounted on the tractor and the equipment mounted on the screed is provided.

It is a side view of the asphalt finisher which concerns on embodiment of this invention. It is a top view of the asphalt finisher of FIG. It is a block diagram which shows the configuration example of the cooperation system. It is a block diagram which shows another configuration example of the cooperation system. It is a block diagram which shows still another configuration example of a cooperation system.

FIG. 1 is a side view of an asphalt finisher 100, which is an example of a road machine according to an embodiment of the present invention. FIG. 2 is a top view of the asphalt finisher 100. The asphalt finisher 100 is mainly composed of a tractor 1, a hopper 2, and a screed 3. In the following, the direction of the hopper 2 as seen from the tractor 1 (+ X direction) is the front, and the direction of the screed 3 as seen from the tractor 1 (−X direction) is the rear. In the tractor 1 of FIG. 2, the side (−Y side) where the driver's cab including the driver's seat 1S is located is on the right side, and the opposite side (+ Y side) is on the left side.

The tractor 1 is a mechanism for running the asphalt finisher 100. In the present embodiment, the tractor 1 uses the rear wheel running hydraulic motor to rotate the rear wheels 5, and uses the front wheel running hydraulic motor to rotate the front wheels 6 to move the asphalt finisher 100. The rear wheel running hydraulic motor and the front wheel running hydraulic motor rotate by receiving the supply of hydraulic oil from the hydraulic pump. The rear wheels 5 and the front wheels 6 may be replaced by crawlers. The tractor 1 is equipped with an engine 11, a generator 12, a controller 50, an operation panel 51, a power supply device 60, and the like.

The hopper 2 is a mechanism for receiving the pavement material. In the present embodiment, it is installed in front of the tractor 1 and is configured to be opened and closed in the Y-axis direction (vehicle width direction) by a hopper cylinder. The asphalt finisher 100 usually receives the pavement material (for example, an asphalt mixture) from the loading platform of the dump truck with the hopper 2 fully open. 1 and 2 show that the hopper 2 is in the fully open state. When the amount of pavement material in the hopper 2 decreases, the hopper 2 is closed, and the pavement material near the inner wall of the hopper 2 is collected in the central portion of the hopper 2. This is so that the conveyor CV in the central portion of the hopper 2 can feed the pavement material behind the tractor 1. The pavement material fed to the rear of the tractor 1 is spread in the vehicle width direction by the screw SC in the rear of the tractor 1 and in front of the screed 3. In the present embodiment, the screw SC is in a state where the extension screw is connected to the left and right. 1 and 2 show the pavement material PV spread by the screw SC with a coarse dot pattern.

The screed 3 is a mechanism for spreading the pavement material PV. In this embodiment, the screed 3 includes a front screed 30 and a rear screed 31. The rear screed 31 is configured to expand and contract in the vehicle width direction (Y-axis direction) as indicated by the bidirectional arrow AR1. Specifically, the rear screed 31 includes a left rear screed 31L that can be expanded and contracted in the vehicle width direction and a right rear screed 31R. The left rear screed 31L and the right rear screed 31R are arranged so as to be offset from each other in the traveling direction (X-axis direction). Therefore, it is possible to have a longer width (length in the vehicle width direction (Y-axis direction)) than when it is not offset, it can be extended longer in the vehicle width direction, and a wider new pavement can be constructed. ..

The screed 3 is a floating screed towed by the tractor 1 and is connected to the tractor 1 via a leveling arm 3A. The screed 3 is equipped with a rear controller 52, a switch box 53, a pavement thickness control device 54, a power supply device 60A, and the like. 1 and 2 show the new pavement NP spread by the screed 3 in a fine dot pattern.

Next, with reference to FIG. 3, the cooperation system CS as a wireless communication system mounted on the asphalt finisher 100 will be described. FIG. 3 is a block diagram showing a configuration example of the cooperation system CS. The cooperation system CS is a system for linking the equipment mounted on the tractor 1 and the equipment mounted on the screed 3, and mainly includes the controller 50 and the operation panel 51 mounted on the tractor 1 and the screed 3. The rear controller 52, the switch box 53, and the pavement thickness control device 54 mounted on the above are included.

In the present embodiment, the controller 50 and the operation panel 51 receive electric power from the electric power supply device 60 mounted on the tractor 1. The power supply device 60 converts the AC power generated by the generator 12 driven by the engine 11 into DC power. The power supply device 60 may include a power storage device. The thick dotted line in FIG. 3 represents the power line, and the double line represents that the engine 11 and the generator 12 are mechanically connected.

The rear controller 52 and the switch box 53 receive electric power from the electric power supply device 60A mounted on the screed 3. The power supply device 60A is a device independent of the power supply device 60, and is, for example, a vibration power generator, a solar power generator, a temperature difference generator, a power storage device, or the like. The power supply device 60A may be removable or non-detachable. The power supply device 60A may be a self-generator that generates electricity by utilizing the operating force (kinetic energy) of the operator who operates the switch. The self-generator may be mounted on each switch. In this case, the switch can wirelessly transmit information about the switch by using the electric power generated from the operating force of the operator who operates the switch. There is no need to provide a power storage device.

The pavement thickness control device 54 controls the thickness of the pavement material laid by the asphalt finisher 100. In the present embodiment, the pavement thickness control device 54 receives power from the built-in power supply device 60B. The power supply device 60B is a device independent of the power supply device 60 and the power supply device 60A, and is, for example, a vibration power generator, a solar power generator, a temperature difference generator, a self-generator, a power storage device, and the like. However, the pavement thickness control device 54 may receive power supply from the power supply device 60 or the power supply device 60A.

The controller 50 is a control device that controls the asphalt finisher 100. In this embodiment, the controller 50 is composed of a microcomputer including a CPU, a volatile storage device, a non-volatile storage device, and the like. Various functions of the controller 50 are realized, for example, by the CPU executing a program stored in the non-volatile storage device.

The controller 50 includes a control unit 50a and a communication unit 50b as functional elements. The control unit 50a and the communication unit 50b are composed of software, hardware, or a combination thereof.

The control unit 50a controls various devices mounted on the asphalt finisher 100. The control unit 50a controls the control valve in response to a control command from, for example, the operation panel 51, the rear controller 52, the switch box 53, the pavement thickness control device 54, and the like. The control valve controls the flow of hydraulic oil between the hydraulic pump driven by the engine 11 and the hydraulic actuator. Hydraulic actuators include front wheel drive hydraulic motor, rear wheel drive hydraulic motor, screw drive hydraulic motor, conveyor drive hydraulic motor, screed telescopic cylinder, leveling cylinder, screen drift cylinder, hopper cylinder, tamper drive hydraulic motor, and vibrator. Includes drive hydraulic motors and the like. The vibrator is a device that vibrates the screed 3.

The communication unit 50b controls wireless communication between the controller 50 and the devices mounted on the tractor 1 and the screed 3. In the present embodiment, the communication unit 50b uses wireless communication standards such as Bluetooth (registered trademark) and Wi-Fi (registered trademark), and wireless communication between the controller 50 mounted on the tractor 1 and the operation panel 51. To control. Further, the communication unit 50b controls wireless communication between the controller 50 and each of the rear controller 52, the switch box 53, and the pavement thickness control device 54 mounted on the screed 3.

The operation panel 51 generates a control command in response to the input of the operator, and outputs the control command to the controller 50. The operation panel 51 includes a switch 51a, a monitor 51b, and a communication unit 51c. In the present embodiment, the operation panel 51 is attached to the front of the driver's seat 1S in the driver's cab.

The switch 51a is an example of an operating device operated by an operator to control the asphalt finisher 100. The switch 51a is, for example, a switch for switching the conveyor CV on / off, a switch for switching the screw SC on / off, a switch for switching the extension / contraction / off of the rear screed 31, and a switch for opening / closing / off the hopper 2. Including switches and the like. The switch is composed of a toggle switch, a rocker switch, a rotary switch, a push switch, a slide switch, a lever switch and the like. The operation panel 51 may include other operation devices such as a dial and a joystick.

The monitor 51b displays various information. In this embodiment, the monitor 51b is a color liquid crystal display. A touch panel may be attached.

The communication unit 51c controls wireless communication between the operation panel 51 and the controller 50. However, the operation panel 51 may be connected to the controller 50 via a communication cable. In this case, the communication unit 51c controls the wired communication between the controller 50 and the operation panel 51 together with the communication unit 50b of the controller 50.

The rear controller 52 generates a control command in response to the input of the operator, and outputs the control command to the controller 50. In the present embodiment, the rear controller 52 has a switch 52a, a monitor 52b, and a communication unit 52c like the operation panel 51, and is attached to the central portion of the screed 3. However, the rear controller 52 may be omitted.

The communication unit 52c controls wireless communication between the rear controller 52 and the controller 50. However, the rear controller 52 may be connected to the controller 50 via a communication cable. In this case, the communication unit 52c controls the wired communication between the controller 50 and the rear controller 52 together with the communication unit 50b of the controller 50.

The switch box 53 generates a control command in response to the input of the operator, and outputs the control command to the controller 50. In the present embodiment, the switch box 53 has a switch 53a, a monitor 53b, and a communication unit 53c like the rear controller 52, and is attached to the right end of the right rear screed 31R and the left end of the left rear screed 31L. There is.

By operating the switch 53a or the like, the operator can turn on / off the conveyor CV, turn on / off the screw SC, adjust the transport speed of the conveyor CV, adjust the rotation speed of the screw SC, and rotate the hydraulic motor for driving the vibrator. The speed can be adjusted, the screed temperature can be adjusted, and the like.

The monitor 53b can display, for example, the transfer speed of the conveyor CV, the rotation speed of the screw SC, the rotation speed of the hydraulic motor for driving the vibrator, the screed temperature, and the like.

The communication unit 53c controls wireless communication between the switch box 53 and the controller 50. However, the switch box 53 may be connected to the controller 50 or the rear controller 52 via a communication cable. In this case, the communication unit 53c controls the wired communication between the switch box 53 and the controller 50 or the rear controller 52 together with the communication unit 50b of the controller 50 or the communication unit 52c of the rear controller 52.

The pavement thickness control device 54 controls the thickness of the pavement material laid by the asphalt finisher 100 by outputting a control command for expanding and contracting the leveling cylinder. The pavement thickness control device 54 includes, for example, a sensor 54a and a communication unit 54b. The sensor 54a is, for example, an ultrasonic sensor attached to the front end of the posterior screed 31 and measuring the vertical distance to the roadbed RB (see FIGS. 1 and 2) in front of the posterior screed 31.

The communication unit 54b controls wireless communication between the pavement thickness control device 54 and the controller 50. However, the pavement thickness control device 54 may be connected to the controller 50, the rear controller 52, or the switch box 53 via a communication cable. In this case, the communication unit 54b, together with the communication unit 50b of the controller 50, the communication unit 52c of the rear controller 52, or the communication unit 53c of the switch box 53, is the pavement thickness control device 54 and the controller 50, the rear controller 52, or the switch box. Controls wired communication with 53.

The pavement thickness control device 54 generates, for example, a control command regarding the amount of expansion and contraction of the leveling cylinder based on the vertical distance detected by the sensor 54a, and outputs the control command to the controller 50. The controller 50 expands and contracts the leveling cylinder by operating a control valve arranged in a pipeline connecting the hydraulic pump and the leveling cylinder in response to the control command. The leveling cylinder adjusts the leveling thickness of the pavement material by moving the front end portion of the leveling arm 3A up and down to adjust the position and posture of the screed 3. The vertical distance detected by the sensor 54a or the information related thereto may be displayed on the monitor 53b of the switch box 53, for example.

Each of the operation panel 51, the rear controller 52, the switch box 53, and the pavement thickness control device 54 may be detachably configured with respect to the asphalt finisher 100. In this case, for example, when the operation panel 51 is removed from the tractor 1, it receives power from the built-in battery and functions as a remote controller. That is, the operator can remotely control the asphalt finisher 100 from a distance from the asphalt finisher 100. When the operation panel 51 is attached to the tractor 1, it operates by receiving power from the power supply device 60, and charges the built-in battery with the power of the power supply device 60. The charging may be contact charging or non-contact charging. The same applies to the rear controller 52, the switch box 53, and the pavement thickness control device 54. Further, each of the operation panel 51, the rear controller 52, the switch box 53, and the pavement thickness control device 54 may be composed of a mobile terminal such as a smartphone, a tablet PC, or a notebook PC.

The cooperation system CS may include a holding amount control device. The holding amount control device controls the holding amount of the pavement material in front of the posterior screed 31. The holding amount control device includes, for example, a holding amount sensor and a communication unit. The holding amount control device receives power from the built-in power supply device, like the pavement thickness control device 54, for example. The holding amount sensor is, for example, an ultrasonic sensor attached to the side plate of the posterior screed 31. In this case, the holding amount sensor measures the distance to the pavement material spread by the screw SC in front of the rear screed 31.

The communication unit controls wireless communication between the holding amount control device and the controller 50. However, the holding amount control device may be connected to the controller 50, the rear controller 52, the switch box 53, or the pavement thickness control device 54 via a communication cable. In this case, the communication unit is the holding amount control device and the controller 50 together with the communication unit 50b of the controller 50, the communication unit 52c of the rear controller 52, the communication unit 53c of the switch box 53, or the communication unit 54b of the pavement thickness control device 54. , Controls wired communication with the rear controller 52, switch box 53 or pavement thickness control device 54.

The holding amount control device determines, for example, whether or not the holding amount is larger than a predetermined amount based on the distance detected by the holding amount sensor. Then, a control command regarding the rotation speed of the screw SC is generated based on the determination result, and the control command is output to the controller 50. The controller 50 adjusts the rotation speed of the screw drive hydraulic motor by operating a control valve arranged in a pipeline connecting the hydraulic pump and the screw drive hydraulic motor in response to the control command. The hydraulic motor for driving the screw increases or decreases the rotation speed of the screw SC to increase or decrease the holding amount. The distance detected by the holding amount sensor or the information related thereto may be displayed on the monitor 53b of the switch box 53, for example.

As described above, the cooperation system CS is configured to perform wireless communication between the device mounted on the tractor 1 and the device mounted on the screed 3. Further, the device mounted on the tractor 1 receives power from the power supply device 60 mounted on the tractor 1, and the device mounted on the screed 3 is a power supply device mounted on the screed 3. It is configured to receive power from 60A. Therefore, there is no power cable and communication cable extending from the tractor 1 to the screed 3. Therefore, there is no possibility that the power cable and the communication cable will be damaged by the heat of the pavement material between the tractor 1 and the screed 3.

Further, the cooperation system CS is configured so that wireless communication is performed between the controller 50 mounted on the tractor 1 and the switch box 53 mounted on the screed 3. Therefore, there is no communication cable extending from the center of the screed 3 toward the switch box 53 attached to the end of the rear screed 31. Therefore, when the rear screed 31 is expanded and contracted, there is no risk that the communication cable will be damaged such as peeling or disconnection.

As described above, the cooperation system CS can alleviate or eliminate the problem of cable damage related to the equipment mounted on the screed 3. Therefore, the device mounted on the tractor 1 and the device mounted on the screed 3 can be linked more stably. As a result, the convenience, stability, workability, productivity and the like of the asphalt finisher 100 can be improved.

Next, another configuration example of the cooperation system CS will be described with reference to FIG. FIG. 4 is a block diagram showing another configuration example of the cooperation system CS. The cooperation system CS of FIG. 4 is different from the cooperation system CS of FIG. 3 in that the rear controller 52 and the switch box 53 receive power from the power supply device 60 mounted on the tractor 1. Further, wireless communication is performed between the rear controller 52 and each of the switch box 53 and the pavement thickness control device 54, that is, wireless communication between the controller 50 and each of the switch box 53 and the pavement thickness control device 54. Is not performed, which is different from the cooperation system CS in FIG. However, the cooperation system CS of FIG. 4 is common to the cooperation system CS of FIG. 3 in other respects.

With this configuration, the cooperation system CS of FIG. 4 can more stably link the device mounted on the tractor 1 and the device mounted on the screed 3 as in the cooperation system CS of FIG. .. Further, the cooperation system CS of FIG. 4 can stably supply electric power to the equipment mounted on the screed 3 as compared with the cooperation system CS of FIG. This is because the device mounted on the screed 3 receives power from the power supply device 60 mounted on the tractor 1. Further, since the communication cable connecting the devices is omitted, the possibility that the communication cable is damaged can be eliminated. In the cooperation system CS of FIG. 4, power line carrier communication may be used.

Next, with reference to FIG. 5, another configuration example of the cooperation system CS will be described. FIG. 5 is a block diagram showing still another configuration example of the cooperation system CS. The cooperation system CS of FIG. 5 is different from the cooperation system CS of FIG. 3 in that wireless communication is performed between the rear controller 52, the switch box 53, and the pavement thickness control device 54, respectively. That is, it differs from the cooperation system CS of FIG. 3 in that wireless communication is not performed between the controller 50, the switch box 53, and the pavement thickness control device 54, respectively. However, the cooperation system CS of FIG. 5 is common to the cooperation system CS of FIG. 3 in other respects.

In the cooperation system CS of FIG. 5, wireless communication is performed between the switch box 53 and the pavement thickness control device 54, and wireless communication is performed between the pavement thickness control device 54 and each of the controller 50 and the rear controller 52. It may be configured not to.

With this configuration, the cooperation system CS of FIG. 5 can more stably link the device mounted on the tractor 1 and the device mounted on the screed 3 in the same manner as the cooperation system CS of FIG. .. Further, the cooperation system CS of FIG. 5 can realize wireless communication regarding the switch box 53 and the pavement thickness control device 54 with lower power than the cooperation system CS of FIG. This is because it is configured so that wireless communication can be performed over a relatively short distance.

As described above, the asphalt finisher 100 according to the embodiment of the present invention is a wireless communication between a tractor 1, a screed 3, and at least two of a plurality of devices mounted on at least one of the tractor 1 and the screed 3. It is equipped with a cooperation system CS as a wireless communication system that enables the above. Therefore, the device mounted on the tractor 1 and the device mounted on the screed 3 can be linked more stably.

The equipment mounted on the tractor 1 includes, for example, at least one of the controller 50 and the operation panel 51, and the equipment mounted on the screed 3 includes the rear controller 52, the switch box 53, the sensor 54a, the screed controller, and the screed controller. , At least one of the power supply devices 60A. The sensor 54a may be a step sensor. The screed controller is a device attached to the screed 3 so that the operator can make various settings related to the screed 3, and has the same configuration as the switch box 53, for example. The power supply device 60A is, for example, a vibration power generator.

As shown in FIGS. 3 to 5, the cooperation system CS may be configured so that wireless communication is performed between the controller 50 and the rear controller 52, and wireless communication is performed between the controller 50 and the operation panel 51. May be configured to be performed. The cooperation system CS may be configured such that wireless communication is performed between the switch box 53, the sensor 54a, and at least one of the screed controllers and the rear controller 52.

The cooperation system CS may be configured such that wired communication is performed between the controller 50 and the rear controller 52, and wireless communication is performed between the controller 50 and the operation panel 51. In the cooperative system CS, wired communication is performed between the controller 50 and the rear controller 52, and wireless communication is performed between at least one of the switch box 53, the sensor 54a, and the screed controller and the rear controller 52. It may be configured to be done.

Even if the asphalt finisher 100 includes, for example, a power supply device 60 as a first power supply device mounted on the tractor 1 and a power supply device 60A as a second power supply device independent of the power supply device 60. Good. Then, at least one of the plurality of devices mounted on at least one of the tractor 1 and the screed 3 may be configured to receive power from the power supply device 60A.

Further, in the present embodiment, the left rear screed 31L and the right rear screed 31R are arranged so as to be offset from each other in the traveling direction (X-axis direction). Therefore, it can be extended longer in the vehicle width direction. However, when the posterior screed 31 is extended, the switch box 53 is located far away from the tractor 1. Therefore, when the switch box 53 performs wired communication, the asphalt finisher needs to have a long cable for the switch box 53. On the other hand, when the rear screed 31 is contracted, the asphalt finisher needs to have space to accommodate the extra portion of the long cable for the switch box 53. In the present embodiment, the asphalt finisher 100 can omit the space for accommodating the cable required for the wired communication by the switch box 53 performing the wireless communication.

The preferred embodiment of the present invention has been described above. However, the present invention is not limited to the above-described embodiments. Various modifications, substitutions, etc. can be applied to the above-described embodiments without departing from the scope of the present invention. In addition, each of the features described with reference to the above-described embodiments may be appropriately combined as long as there is no technical conflict.

This application claims priority based on Japanese Patent Application No. 2017-149062 filed on August 1, 2017, and the entire contents of this Japanese patent application are incorporated herein by reference.

1 ... tractor 1S ... driver's seat 2 ... hopper 3 ... screed 3A ... leveling arm 5 ... rear wheel 6 ... front wheel 11 ... engine 12 ... generator 30・ ・ ・ Front side pavement 31 ・ ・ ・ Rear side pavement 31L ・ ・ ・ Left rear side pavement 31R ・ ・ ・ Right rear side pavement 50 ・ ・ ・ Controller 50a ・ ・ ・ Control unit 50b ・ ・ ・ Communication unit 51 ・ ・ ・ Operation Panel 51a ... Switch 51b ... Monitor 51c ... Communication unit 52 ... Rear controller 52a ... Switch 52b ... Monitor 52c ... Communication unit 53 ... Switch box 53a ... Switch 53b ... Monitor 53c ... Communication unit 54 ... Pavement thickness control device 54a ... Sensor 54b ... Communication unit 60, 60A, 60B ... Power supply device 100 ... Asphalt finisher CV ...・ Conveyor NP ・ ・ ・ New pavement PV ・ ・ ・ Pavement material RB ・ ・ ・ Roadbed SC ・ ・ ・ Screw

Claims (9)

With a tractor
With screed
A wireless communication system configured to allow wireless communication between at least two of a plurality of devices mounted on at least one of the tractor and the screed.
Asphalt finisher. The equipment mounted on the tractor includes at least one of a controller and an operation panel.
The equipment mounted on the screed includes at least one of a rear controller, a switch box, a sensor, a screed controller, and a vibration power generator.
The asphalt finisher according to claim 1. The wireless communication system is configured to perform wireless communication between the controller and the rear controller.
The asphalt finisher according to claim 2. The wireless communication system is configured to perform wireless communication between the controller and the operation panel.
The asphalt finisher according to claim 2. The wireless communication system is configured such that wireless communication is performed between the switch box, the sensor, and at least one of the screed controllers and the rear controller.
The asphalt finisher according to claim 2. The wireless communication system is configured such that wired communication is performed between the controller and the rear controller, and wireless communication is performed between the controller and the operation panel.
The asphalt finisher according to claim 2. In the wireless communication system, wired communication is performed between the controller and the rear controller, and wireless communication is performed between the switch box, the sensor, and at least one of the screed controllers and the rear controller. It is configured for communication,
The asphalt finisher according to claim 2. The first power supply device mounted on the tractor and
A second power supply device independent of the first power supply device is provided.
At least one of the plurality of devices mounted on at least one of the tractor and the screed receives power from the second power supply device.
The asphalt finisher according to claim 1. The screed includes a left rear screed and a right rear screed that can be expanded and contracted in the vehicle width direction.
The left posterior screed and the right posterior screed are offset from each other in the traveling direction.
The asphalt finisher according to claim 1.

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