ASPHALT FINISHER

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001]This application is based upon and claims priority to Japanese Patent Application No. 2024-207833, filed on Nov. 29, 2024, the entire contents of which are incorporated herein by reference.

BACKGROUND

1. Technical Field

[0002]The present disclosure relates to an asphalt finisher.

2. Description of Related Art

[0003]Asphalt finishers are known to have a configuration in which a retaining plate is disposed in front of a screw configured to lay and spread a paving material, thereby preventing the paving material from scattering forward. In this configuration, a screed configured to compact the paving material is disposed rearward of the screw. Some of the known asphalt finishers are configured to be extendible in the width of the screed in the vehicle-width direction.

SUMMARY

[0004]According to the present disclosure, an asphalt finisher includes: a tractor; a screw configured to lay and spread a paving material rearward of the tractor; a screed configured to compact the paving material rearward of the screw; a retaining plate disposed in front of the screw; and a connector configured to connect the screed and the retaining plate. The screed is configured to be extendible or contractible in a width of the screed in a vehicle-width direction. The retaining plate is configured to be extendible or contractible in a width of the retaining plate in the vehicle-width direction in conjunction with, via the connector, extension or contraction of the width of the screed in the vehicle-width direction.

BRIEF DESCRIPTION OF THE DRAWINGS

[0005]FIG. 1 is a left side diagram schematically illustrating an asphalt finisher according to an embodiment of the present disclosure;

[0006]FIG. 2 is a top plan diagram schematically illustrating the asphalt finisher according to the embodiment of the present disclosure;

[0007]FIG. 3 is a block diagram illustrating configuration examples of a controller and devices connected to the controller according to the embodiment of the present disclosure;

[0008]FIG. 4 is a diagram illustrating configurations of a screw and a screed in the asphalt finisher according to the embodiment of the present disclosure;

[0009]FIG. 5 is a diagram describing connection between a side plate and a retaining plate via a linker according to the embodiment of the present disclosure;

[0010]FIG. 6A is a diagram of a state, as viewed from above, in which a left linker is attached to a left side plate;

[0011]FIG. 6B is a diagram of the state, as viewed laterally, in which the left linker is attached to the left side plate;

[0012]FIG. 7 is a diagram describing effects provided by the linker according to the embodiment of the present disclosure;

[0013]FIG. 8 is a diagram describing the effects provided by the linker according to the embodiment of the present disclosure;

[0014]FIG. 9 is a diagram describing a method of housing the linker according to the embodiment of the present disclosure;

[0015]FIG. 10 is a diagram describing the method of housing the linker according to the embodiment of the present disclosure;

[0016]FIG. 11 is a diagram describing effects when the height of the screed changes; and

[0017]FIG. 12 is a diagram describing the effects when the height of the screed changes.

DETAILED DESCRIPTION

[0018]When the width of the screed in the vehicle-width direction is extended, and, for example, an extended screw is linked to the screed in accordance with the extended width of the screed, the width of the retaining plate needs to be extended. Unless the width of the retaining plate is extended, the paving material is likely to scatter forward, and is unlikely to be smoothly transferred to both ends of the screw. Manual work for extending the width of the retaining plate needs a great deal of labor and time, causing a reduction in work efficiency.

[0019]Related art discloses a configuration that extends the width of a retaining plate by use of a hydraulic or pneumatic pressure under control of a control unit.

[0020]However, in the configuration disclosed in the related art, a hydraulic cylinder, a pneumatic cylinder, and a circuit and the like in the control unit are required for extending the width of the retaining plate. As a result, the configuration becomes complicated, leading to an increase in cost. Further, when newly adding the configuration disclosed in the related art, the retaining plate and the control unit must be modified, and a large number of steps are required for this purpose.

[0021]The present disclosure provides an asphalt finisher configured to extend or contract, in a simple configuration, the width of a retaining plate disposed in front of a screw configured to lay and spread a paving material.

[0022]Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the same or corresponding components are denoted by the same symbols, and description thereof may be omitted.

[0023]FIG. 1 is a left side diagram schematically illustrating an asphalt finisher 100 according to an embodiment of the present disclosure. FIG. 2 is a top plan diagram schematically illustrating the asphalt finisher 100 according to the embodiment of the present disclosure.

[0024]The asphalt finisher 100 mainly includes a tractor 1, a hopper 2, and a screed 3. In the example illustrated in FIG. 1, the asphalt finisher 100 is disposed such that a vehicle-length direction corresponds to an X-axis direction and a vehicle-width direction corresponds to a Y-axis direction. A Z axis is orthogonal to an X axis and a Y axis. Specifically, a front side in the vehicle-length direction corresponds to a +X side, a rear side in the vehicle-length direction corresponds to a −X side, a left side in the vehicle-width direction corresponds to a +Y side, a right side in the vehicle-width direction corresponds to a −Y side, an upper side in the vertical direction corresponds to a +Z side, and a lower side in the vertical direction corresponds to a −Z side.

[0025]The tractor 1 is a mechanism configured to move the asphalt finisher 100. In the examples illustrated in FIGS. 1 and 2, the tractor 1 moves the asphalt finisher 100 by rotating rear wheels 5 using rear wheel drive motors and rotating front wheels 6 using front wheel drive motors. The rear wheel drive motors and the front wheel drive motors are both hydraulic motors configured to rotate by receiving hydraulic oil suppled from a hydraulic pump. However, the tractor 1 may include crawlers instead of the wheels.

[0026]The asphalt finisher 100 according to the present embodiment changes a moving direction by controlling the steering angles of the front wheels 6. When the asphalt finisher 100 includes the crawlers instead of the wheels, the moving direction is changed by causing the rotation speed of drive sprockets in the right crawler and the rotation speed of drive sprockets in the left crawler to be different from each other.

[0027]The hopper 2 is a mechanism configured to receive a paving material. The paving material is, for example, an asphalt mixture. In the examples illustrated in FIGS. 1 and 2, the hopper 2 is disposed on the front side (+X side) of the tractor 1, and is configured by hopper cylinders 24 to be opened or closed in the Y-axis direction (vehicle-width direction). The asphalt finisher 100 typically receives the paving material from the loading bed of a dump truck with the hopper 2 fully opened. Also, when the asphalt finisher 100 is receiving the paving material from the loading bed of the dump truck, the asphalt finisher 100 continues to move while pushing the dump truck forward with a pushing roller 2b. FIGS. 1 and 2 illustrate the asphalt finisher 100 in a state in which the hopper 2 is fully opened. When the paving material in the hopper 2 decreases, an operator of the asphalt finisher 100 closes the hopper 2 and collects the paving material near the inner walls of the hopper 2 toward a center portion of the hopper 2. By this, conveyors CV at the bottom of the center portion of the hopper 2 can convey the paving material to the rear side of the tractor 1. The paving material conveyed to the rear side (−X side) of the tractor 1 is laid and spread in the vehicle-width direction by screws SC on the rear side of the tractor 1 and on the front side of the screed 3.

[0028]Each of the hopper cylinders 24 is a hydraulic actuator configured to open and close the hopper 2, and contracts when the hopper 2 is opened and extends when the hopper 2 is closed. The hopper cylinders 24 include a left hopper cylinder 24L and a right hopper cylinder 24R.

[0029]The conveyors CV are driven by a hydraulic motor configured to rotate by receiving hydraulic oil supplied from a hydraulic pump. In the examples illustrated in FIGS. 1 and 2, the conveyors CV are configured to convey the paving material in the hopper 2 to the rear side of the tractor 1 through a conveying path. The conveying path is a substantially rectangular parallelepiped space formed inside the tractor 1, and includes a substantially rectangular inlet OP configured to open toward the interior of the hopper 2 at the front surface of the tractor 1. Specifically, the conveyors CV include a left conveyor and a right conveyor.

[0030]The screws SC lay and spread the paving material on the rear side of the tractor 1. The screws SC are driven by a hydraulic motor configured to rotate by receiving hydraulic oil supplied from a hydraulic pump. Specifically, the screws SC include a left screw SCL provided on the left side of the asphalt finisher 100, and a right screw SCR provided on the right side of the asphalt finisher 100.

[0031]The screed 3 is configured to compact the paving material on the rear side of the screws SC. The screed 3 is a mechanism configured to level the paving material. In the examples illustrated in FIGS. 1 and 2, the screed 3 mainly includes main screeds 30 and extendible or contractible (extendible/contractible) screeds 31. The main screeds 30 include a left main screed and a right main screed. The extendible/contractible screeds 31 include a left extendible/contractible screed 31L and a right extendible/contractible screed 31R. The main screeds 30, the left extendible/contractible screed 31L, and the right extendible/contractible screed 31R are disposed at positions different in a front-back direction such that they do not overlap with each other in the vehicle-length direction. Specifically, the left extendible/contractible screed 31L is disposed on the rear side of the main screeds 30, and the right extendible/contractible screed 31R is disposed on the rear side of the left extendible/contractible screed 31L. The screed 3 is a floating screed pulled by the tractor 1, and is connected to the tractor 1 via leveling arms 3A. The screed 3 is moved upward or downward along with the leveling arms 3A due to extension or contraction (extension/contraction) of screed lift cylinders 25. The leveling arms 3A include a left leveling arm 3AL and a right leveling arm 3AR.

[0032]The extendible/contractible screeds 31 are configured to have widths that are extendible/contractible in the vehicle-width direction, by screed extendible/contractible cylinders 27. The screed extendible/contractible cylinders 27 are supported by supports fixed to the rear surface of a casing of the main screeds 30, and are configured to extend or contract (extend/contract) the extendible/contractible screeds 31 in the vehicle-width direction (Y-axis direction). Specifically, the screed extendible/contractible cylinders 27 include a left screed extendible/contractible cylinder 27L (an example of a left screed device) and a right screed extendible/contractible cylinder 27R (an example of a right screed device). The left screed extendible/contractible cylinder 27L can extend/contract the left extendible/contractible screed 31L on the left side in the vehicle-width direction relative to the main screeds 30. The right screed extendible/contractible cylinder 27R can extend/contract the right extendible/contractible screed 31R on the right side in the vehicle-width direction relative to the main screeds 30.

[0033]The leveling arms 3A are configured to connect the screed 3 to the tractor 1. Specifically, one end of each of the leveling arms 3A is connected to the screed 3, and the other end of each of the leveling arms 3A is connected to the tractor 1 to be rotatable.

[0034]Leveling cylinders 23 are hydraulic cylinders configured to vertically move the front ends of the leveling arms 3A for adjusting a paving material leveling thickness (pavement thickness). In the examples illustrated in FIGS. 1 and 2, cylinder portions of the leveling cylinders 23 are connected to the tractor 1, and rod portions of the leveling cylinders 23 are connected to the front ends of the leveling arms 3A. The front ends of the leveling arms 3A are supported by the tractor 1 to be slidable. When increasing the pavement thickness, a controller 50 causes hydraulic oil discharged by a hydraulic pump to flow into oil chambers on the rod sides of the leveling cylinders 23, and contracts the leveling cylinders 23 to raise the front ends of the leveling arms 3A. Conversely, when decreasing the pavement thickness, the controller 50 causes the hydraulic oil to flow out of the oil chambers on the rod sides of the leveling cylinders 23, and extends the leveling cylinders 23 to lower the front ends of the leveling arms 3A. The leveling cylinders 23 include a left leveling cylinder 23L and a right leveling cylinder 23R.

[0035]The screed lift cylinders 25 are hydraulic cylinders configured to lift the screed 3. In the examples illustrated in FIGS. 1 and 2, cylinder portions of the screed lift cylinders 25 are connected to the tractor 1, and rod portions of the screed lift cylinders 25 are connected to the rear ends of the leveling arms 3A. When lifting the screed 3, the controller 50 causes hydraulic oil discharged by a hydraulic pump to flow into oil chambers on the rod sides of the screed lift cylinders 25. This causes the screed lift cylinders 25 to contract, thereby lifting the rear ends of the leveling arms 3A, i.e., lifting the screed 3. Conversely, when lowering the lifted screed 3, the controller 50 causes the hydraulic oil to be flowable out of the oil chambers on the rod sides of the screed lift cylinders 25. This causes the screed lift cylinders 25 to extend due to the weight of the screed 3, thereby lowering the rear ends of the leveling arms 3A, i.e., lowering the screed 3. The screed lift cylinders 25 include a left screed lift cylinder 25L and a right screed lift cylinder 25R.

[0036]Side plates 40 are attached to the outer ends of the extendible/contractible screeds 31 in the vehicle-width direction. The side plates 40 include a left side plate 40L and a right side plate 40R. Specifically, the left side plate 40L is attached to the outer end (left end) of the left extendible/contractible screed 31L, and the right side plate 40R is attached to the outer end (right end) of the right extendible/contractible screed 31R.

[0037]As illustrated in FIG. 2, the ends of the side plates 40 on the front side in the moving direction (positive X-axis direction) extend up to extensions of the screws SC in the longitudinal direction (rotation axis direction).

[0038]The side plates 40 are also attached to the outer ends of extendible/contractible mold boards 41. The extendible/contractible mold boards 41 are members configured to adjust the amount of the paving material remaining in front of the extendible/contractible screeds 31 in the paving material laid and spread by the screws SC, and configured to be extendible/contractible in the vehicle-width direction along with the extendible/contractible screeds 31.

[0039]Specifically, the extendible/contractible mold boards 41 are plate-like members extending in the vehicle-width direction, and include a left extendible/contractible mold board 41L and a right extendible/contractible mold board 41R. The left side plate 40L (an example of a plate portion) is attached to the outer end (left end) of the left extendible/contractible mold board 41L, and the right side plate 40R (an example of a plate portion) is attached to the outer end (right end) of the right extendible/contractible mold board 41R.

[0040]The extendible/contractible mold boards 41 are configured to adjust the height in a Z-axis direction independently of the extendible/contractible screeds 31 and the side plates 40. By moving the extendible/contractible mold boards 41 upward or downward to adjust the size of a gap between the lower end of the extendible/contractible mold board 41 and the subbase, the asphalt finisher 100 can adjust the amount of the paving material passing through that gap. Therefore, by moving the extendible/contractible mold boards 41 upward or downward, the asphalt finisher 100 can adjust the amount (height) of the paving material remaining on the rear side (−X side) of the extendible/contractible mold boards 41 and on the front side (+X side) of the extendible/contractible screeds 31, and hence can adjust the amount of the paving material taken into the underside of the extendible/contractible screeds 31.

[0041]Screed steps 42 are members configured to form a scaffold used when an operator works rearward of the screed 3. Specifically, the screed steps 42 include a left screed step 42L, a center screed step 42C, and a right screed step 42R.

[0042]Retaining plates 43 are plate-like members configured to prevent the paving material, delivered by the screws SC in the vehicle-width direction, from scattering forward of the screws SC, such that the screws SC appropriately deliver the paving material in the vehicle-width direction. Therefore, the retaining plates 43 are disposed in front of the screws SC. In the examples illustrated in FIGS. 1 and 2, the retaining plate 43 includes a left retaining plate 43L and a right retaining plate 43R.

[0043]The asphalt finisher 100 according to the present embodiment includes linkers 60. The linkers 60 are an example of the connector in the present disclosure, and include a left linker 60L and a right linker 60R. The left linker 60L is attached to the left side plate 40L and the left retaining plate 43L, thereby connecting the left extendible/contractible screed 31L and the left retaining plate 43L. The right linker 60R is attached to the right side plate 40R and the right retaining plate 43R, thereby connecting the right extendible/contractible screed 31R and the right retaining plate 43R. Details of the linkers 60 will be described below.

[0044]The controller 50 is a control device configured to control the asphalt finisher 100. In the examples illustrated in FIGS. 1 and 2, the controller 50 is a computer including a CPU, a volatile storage device, and a non-volatile storage device, and is mounted in the tractor 1. Various functions of the controller 50 are implemented, for example, by the CPU executing a program stored in the non-volatile storage device. Various functions implemented by the controller 50 include, for example, a function of controlling the amount of hydraulic oil to be discharged by the hydraulic pump configured to supply the hydraulic oil for driving hydraulic actuators, and a function of controlling the flow of hydraulic oil between the hydraulic actuators and the hydraulic pump. The hydraulic actuators include hydraulic cylinders and hydraulic motors.

[0045]A communication device 53 is configured to control communication between the asphalt finisher 100 and devices outside the asphalt finisher 100. The communication device 53 according to the present embodiment is disposed in front of a driver's seat 1S, and is configured to control communication via a cellular telephone communication network, a short-range wireless communication network, a satellite communication network, or the like.

[0046]A GPS module 54 is an example of a global navigation satellite system (GNSS) module, and is configured to receive position information indicating results of two-dimensional positioning performed by a global positioning system (GPS). The position information includes information representing the position of the asphalt finisher 100 using a latitude and a longitude. In the present embodiment, the GPS is used as a method of obtaining the position information. However, no limitation is imposed on the method of obtaining the position information, and any other well-known method may be used.

[0047]Space recognition devices 51 are attached to the tractor 1. The space recognition devices 51 are configured to obtain information of a space around the asphalt finisher 100, and output the obtained information to the controller 50. The space recognition devices 51 according to the present embodiment include a forward monitoring device 51F, a rearward monitoring device 51B, a rightward monitoring device 51R, and a leftward monitoring device 51L.

[0048]The forward monitoring device 51F is configured to monitor a space in front of the asphalt finisher 100. In the present embodiment, the forward monitoring device 51F is a LIDAR sensor configured to monitor a space in front of the tractor 1 as a monitoring range RF, and is attached to the center of the front end of an upper surface of the tractor 1. The forward monitoring device 51F may be attached to any other portion of the asphalt finisher 100.

[0049]The rearward monitoring device 51B is configured to monitor a space rearward of the asphalt finisher 100. In the present embodiment, the rearward monitoring device 51B is a LIDAR sensor configured to monitor a space rearward of the screed 3 as a monitoring range RB, and is attached to a guide rail 1G configured to function as a handrail for the operator of the asphalt finisher 100. The rearward monitoring device 51B may be attached to a lower portion of the driver's seat 1S, or may be attached to any other portion of the asphalt finisher 100.

[0050]The rightward monitoring device 51R is configured to monitor a space rightward of the asphalt finisher 100. The leftward monitoring device 51L is configured to monitor a space leftward of the asphalt finisher 100. The rightward monitoring device 51R and the leftward monitoring device 51L according to the present embodiment are set to include, as monitoring ranges, the ends of a road surface (the boundaries between the road surface and the road shoulders) and the side plates 40 provided at the outer ends of the extendible/contractible screeds 31. The rightward monitoring device 51R and the leftward monitoring device 51L are, for example, a LIDAR sensor, and are attached to the guide rail 1G configured to function as the handrail for the operator of the asphalt finisher 100. The rightward monitoring device 51R and the leftward monitoring device 51L may be attached at any positions lateral to the asphalt finisher 100 as long as the monitoring ranges described above are included.

[0051]The LIDAR sensor measures, for example, distances between one million or more points within the monitoring range and the LIDAR sensor. However, at least one of the forward monitoring device 51F or the rearward monitoring device 51B may be a monocular camera, a stereo camera, a millimeter wave radar sensor, a laser radar sensor, a laser scanner, a distance image camera, a laser range finder, or the like. The same applies to the rightward or leftward monitoring device. The embodiment is described based on an example of using a LIDAR sensor as an example of the space recognition device 51. However, the present embodiment does not intend to limit the space recognition device 51 to a LIDAR sensor. That is, the space recognition device 51 may be any space recognition device configured to recognize a space from the asphalt finisher 100 serving as a reference.

[0052]The monitoring range RF of the forward monitoring device 51F includes the subbase. The same applies to the monitoring range of the rightward or leftward monitoring device. In the present embodiment, the monitoring range RF has a width greater than the width of a subbase BS.

[0053]The monitoring range RB of the rearward monitoring device 51B includes a new pavement body. In the present embodiment, the monitoring range RB has a width greater than the width of the new pavement body.

[0054]Measurement information detected by the space recognition device 51 according to the present embodiment is transmitted to the controller 50. The controller 50 according to the present embodiment may perform automatic steering of the asphalt finisher 100 based on the received measurement information. Also, the controller 50 may notify the operator of an alert or the like based on the received measurement information.

[0055]Next, the controller 50 mounted in the asphalt finisher 100 will be described with reference to FIG. 3. FIG. 3 is a block diagram illustrating configuration examples of the controller 50 and the devices connected to the controller 50.

[0056]As illustrated in FIG. 3, the controller 50 is connected to moving speed sensors 47, an auxiliary storage device 48, the GPS module 54, the forward monitoring device 51F, the rearward monitoring device 51B, a drive system controller 52, a communication device 53, a screed control device 55, and a screed length detection device 57.

[0057]The moving speed sensors 47 are configured to detect the moving speed of the asphalt finisher 100. In the example illustrated in FIG. 3, the moving speed sensors 47 are encoders configured to detect the angular speeds of rotary shafts of the rear wheel drive motors configured to drive the rear wheels 5. Specifically, the moving speed sensors 47 include a left moving speed sensor and a right moving speed sensor. The left moving speed sensor is the encoder configured to detect the angular speed of the rotary shaft of a left rear wheel drive motor configured to drive a left rear wheel. The right moving speed sensor is the encoder configured to detect the angular speed of the rotary shaft of a right rear wheel drive motor configured to drive a right rear wheel. The moving speed sensors 47 may include a proximity switch or the like configured to detect a slit formed in a rotating plate.

[0058]The auxiliary storage device 48 is configured to store various types of information. In the example illustrated in FIG. 3, the auxiliary storage device 48 is a non-volatile storage device mounted in the tractor 1, and stores various types of information. For example, the auxiliary storage device 48 stores a schedule information storage part 48a and a vehicle-width storage part 48b.

[0059]The schedule information storage part 48a stores schedule information for constructing a road surface to be paved by the asphalt finisher 100. The schedule information according to the present embodiment includes, for example, a centerline of a path along which the asphalt finisher 100 is to be moved, and target lines indicating the ends of a road surface (the boundaries between the road surface and the road shoulders). The asphalt finisher 100 according to the present embodiment performs automatic control of paving of the road in accordance with the schedule information.

[0060]The vehicle-width storage part 48b stores information of lengths from a structural center position of the asphalt finisher 100 to the side surfaces of the asphalt finisher 100 in the vehicle-width direction. Here, the structural center position is a center position, in the vehicle-width direction, between the left side surface and the right side surface of the asphalt finisher 100.

[0061]Therefore, the controller 50 enables calculation of the distances from the center position of the asphalt finisher 100 in the vehicle-width direction to the side plates 40 in accordance with the lengths of the extendible/contractible screeds 31 in the vehicle-width direction.

[0062]The GPS module 54 is an example of a global navigation satellite system (GNSS) module, and is configured to receive position information indicating results of two-dimensional positioning performed by a global positioning system (GPS). The position information includes information representing the position of the asphalt finisher 100 with a latitude and a longitude. In the present embodiment, the GPS is used as a method of obtaining the position information. However, no limitation is imposed on the method of obtaining the position information, and any other well-known method may be used.

[0063]The screed length detection device 57 (an example of a detection part) is configured to detect the length of extension/contraction, in the vehicle-width direction, of the left extendible/contractible screed 31L and a right extendible/contractible screed 31R. The screed length detection device 57 may use any sensor as long as it can detect the lengths of extension/contraction of the extendible/contractible screeds 31 in the vehicle-width direction. The screed length detection device 57 may be a laser sensor or the like configured to detect the length of extension/contraction, or may be GNSS modules provided to the side plates 40. For example, the lengths of extension/contraction of the extendible/contractible screeds 31 in the vehicle-width direction may be calculated from the distance between position information detected by the GNSS module and position information of the GNSS module provided to the body of the asphalt finisher 100. As another example, instead of the screed length detection device 57, the controller 50 may determine the lengths of extension/contraction of the extendible/contractible screeds 31 in the vehicle-width direction in accordance with measurement information of the rightward monitoring device 51R and the leftward monitoring device 51L.

[0064]The communication device 53 performs wireless communication with a device existing around the asphalt finisher 100, a server configured to manage a work site, and the like. In the present embodiment, one or more of Wi-Fi (registered trademark), a wireless LAN, Bluetooth (registered trademark), and the like may be used as the wireless communication standard of the communication device 53.

[0065]The drive system controller 52 is configured to control the tractor 1 in accordance with a control command. For example, the drive system controller 52 controls the speed and steering angle of the tractor 1.

[0066]The screed control device 55 is configured to control an amount of extension/contraction of the extendible/contractible screeds 31. In the example illustrated in FIG. 3, the screed control device 55 controls a flow rate of hydraulic oil flowing into the screed extendible/contractible cylinders 27.

[0067]In accordance with a control command from the controller 50, the screed control device 55 performs: control to contract the left screed extendible/contractible cylinder 27L to contract the left extendible/contractible screed 31L; and control to extend the left screed extendible/contractible cylinder 27L to extend the left extendible/contractible screed 31L.

[0068]In accordance with a control command from the controller 50, the screed control device 55 performs: control to contract the right screed extendible/contractible cylinder 27R to contract the right extendible/contractible screed 31R; and control to extend the right screed extendible/contractible cylinder 27R to extend the right extendible/contractible screed 31R.

[0069]In this manner, the screed control device 55 controls the respective lengths of the right extendible/contractible screed 31R and the left extendible/contractible screed 31L in accordance with the control commands from the controller 50.

[0070]The controller 50 obtains information from the GPS module 54, the forward monitoring device 51F, the rearward monitoring device 51B, the rightward monitoring device 51R, the leftward monitoring device 51L, the moving speed sensor 47, the screed length detection device 57, and the auxiliary storage device 48, followed by performing various calculations. In accordance with the obtained calculation results, the controller 50 outputs control commands to the screed control device 55 and the drive system controller 52.

[0071]Each of the functional blocks in the controller 50 is conceptual, and does not necessarily need to be physically configured as illustrated in FIG. 3. All or a part of each functional block can be functionally or physically distributed or integrated in desired units. All or a part of each processing function performed in each functional block is implemented in accordance with a program executed in the CPU. Alternatively, each functional block may be implemented as hardware of wired logic. The program executed by the controller 50 according to the present embodiment is not limited to being stored in a non-volatile auxiliary storage device, and may be stored in a distributable storage medium or transmitted/received through a communication line.

[0072]The controller 50 according to the present embodiment performs localization in accordance with the detection results obtained from the GPS module 54, the forward monitoring device 51F, the rearward monitoring device 51B, and the moving speed sensor 47, and performs automatic moving control for asphalt paving of a road surface indicated by the schedule information stored in the auxiliary storage device 48.

[0073]Here, for preventing the paving material from projecting outside the road surface to be paved, the controller 50 transmits, to the screed control device 55, a control command to extend or contract the extendible/contractible screeds 31 based on the measurement information obtained from the rightward monitoring device 51R, the leftward monitoring device 51L, and the screed length detection device 57.

[0074]More specifically, the controller 50 includes an obtainment part 50a, a movement path calculation part 50b, a movement control part 50c, and a screed control part 50d, as functional blocks formed of software, hardware, or a combination of software and hardware.

[0075]The obtainment part 50a is configured to obtain various types of information. For example, the obtainment part 50a obtains measurement information from various sensors. For example, the obtainment part 50a obtains measurement information detected by the forward monitoring device 51F, the rearward monitoring device 51B, the rightward monitoring device 51R, and the leftward monitoring device 51L. Also, the obtainment part 50a obtains measurement information detected by the moving speed sensor 47 (e.g., the speed of the asphalt finisher 100). Also, the obtainment part 50a obtains measurement information from the screed length detection device 57 (the length of extension/contraction, in the vehicle-width direction, of each of the left extendible/contractible screed 31L and the right extendible/contractible screed 31R). Further, the obtainment part 50a obtains position information from the GPS module 54. Further, the obtainment part 50a obtains information from the auxiliary storage device 48, if necessary. Also, the obtainment part 50a may obtain steering angle information from the tractor 1.

[0076]The movement path calculation part 50b is configured to calculate a target movement path of the asphalt finisher 100 based on the schedule information read out from the schedule information storage part 48a. The target movement path is, for example, information indicating a path along which a structural center position of the asphalt finisher 100 in the vehicle-width direction moves in order for the asphalt finisher 100 to construct the road surface. Here, the structural center position is a center position, in the vehicle-width direction, between the left side surface and the right side surface of the asphalt finisher 100. The target movement path may be obtained by any method other than the calculation in the controller 50, and may be received from an external device through the communication device 53. Further, the target movement path is not limited to the above-described path, and may be any path as long as it is a path along which the asphalt finisher 100 can move. The target movement path is, for example, a trajectory of a left front wheel of the tractor 1.

[0077]The movement control part 50c is configured to output, to the drive system controller 52, a control command based on the measurement information and position information obtained by the obtainment part 50a, such that the asphalt finisher 100 moves along the calculated target movement path. Thus, automatic moving control of the asphalt finisher 100 is performed.

[0078]The screed control part 50d is configured to output, to the screed control device 55, a control command to extend/contract the extendible/contractible screeds 31 based on the measurement information (an example of the detection results) from the rightward monitoring device 51R, the leftward monitoring device 51L, and the screed length detection device 57, so as to correspond to the width of the road surface where the paving material is to be spread. This can coincide the length of the screed 3 in the vehicle-width direction with the width of a road to be constructed, thereby enabling the paving material to be appropriately laid and leveled on the road surface to be paved.

[0079]FIG. 4 is a diagram illustrating configurations of the screw SC and the screed 3 in the asphalt finisher 100 according to the embodiment. FIG. 4 is an example in which the asphalt finisher 100 moves in a moving direction 4001. The screw SC provided in the asphalt finisher 100 rotates in a direction 4002 in accordance with a control signal from the controller 50. Thus, the paving material is pushed out in a direction 4003.

[0080]In the example illustrated in FIG. 4, the end of the road surface to be paved (the boundary between the road surface and the road shoulder) is set as a target line OL of the side plate 40 of the asphalt finisher 100 (left target line OLL).

[0081]When the asphalt finisher 100 moves in the moving direction 4001, as the road surface changes or the steering angle of the asphalt finisher 100 changes, the target line OL, which is the boundary between the road surface and the road shoulder, is shifted rightward or leftward of a reference, i.e., the center position of the asphalt finisher 100 in the vehicle-width direction.

[0082]The obtainment part 50a of the controller 50 according to the present embodiment detects deviation (change) of the target lines OL (e.g., the left target line OLL) based on the measurement information obtained from the rightward monitoring device 51R and the leftward monitoring device 51L. Based on the detection results, the screed control part 50d transmits, to the screed control device 55, a control command for extending/contracting the extendible/contractible screeds 31 such that the side plates 40 become along the target lines (e.g., the left target line OLL).

[0083]Thus, the side plate 40 can move in a right direction 4011 or a left direction 4012 to follow the target line OL.

[0084]The linker 60 will be described in detail below. Although the following is described about a relationship between the left retaining plate 43L of the left linker 60L of the linkers 60, and the left side plate 40L, the same applies to a relationship between the right retaining plate 43R of the right linker 60R of the linkers 60, and the right side plate 40R.

[0085]First, the configurations of the linkers 60 and the connections between the side plates 40 and the retaining plates 43 via the linkers 60 will be described.

[0086]FIG. 5 is a diagram describing the connection between the side plate 40 and the retaining plate 43 via the linker 60 according to the present embodiment. Specifically, FIG. 5 is a perspective diagram of the vicinity of the left linker 60L. FIG. 6A is a diagram of a state, as viewed from above, in which the left linker 60L is attached to the left side plate 40L. FIG. 6B is a diagram of the state, as viewed laterally, in which the left linker 60L is attached to the left side plate 40L.

[0087]As illustrated in FIG. 5, the left linker 60L (linker 60) has an L shape in which two side portions 61a and 61b cross at a right angle, and one side portion 61a of the two side portions 61a and 61b is disposed to extend in the vehicle-width direction (Y-axis direction).

[0088]Two fixing plates 62a and 62b are attached to the tip end of the other side portion 61b of the two side portions 61a and 61b. As illustrated in FIG. 6A, the two fixing plates 62a and 62b are attached to the side portion 61b through welding or the like to sandwich the side portion 61b, such that portions of the two fixing plates 62a and 62b project from the tip end of the side portion 61b. The two fixing plates 62a and 62b are attached to the side portion 61b to face each other in the vehicle-width direction (Y-axis direction) when an axis direction of the side portion 61b is directed in the vehicle-length direction (X-axis direction). The side portion 61b of the left linker 60L as configured above is attached to the left side plate 40L.

[0089]A mounting cylinder 63 is attached to the left side plate 40L (side plates 40) near a front end side of the left side plate 40L. The mounting cylinder 63 is an example of a mounting portion in the present disclosure. The mounting cylinder 63 has a cylindrical shape, and is attached to penetrate through the left side plate 40L with an axis direction of the mounting cylinder 63 being directed in the vehicle-width direction (Y-axis direction). The front end side of the left side plate 40L is inclined as illustrated in FIG. 5 and FIG. 6B. Specifically, the front end side of the left side plate 40L is inclined such that an upper end of the left side plate 40L is located behind a lower end of the left side plate 40L.

[0090]A stopper 68 is attached to a tip end of the side portion 61a of the two side portions 61a and 61b. The stopper 68 is, for example, a plate-like member, and is attached to the side portion 61a such that a flat plane of the stopper 68 is directed in an axis direction of the side portion 61a. The side portion 61a of the left linker 60L as configured above is attached to the left retaining plate 43L.

[0091]The left retaining plate 43L (retaining plate 43) includes a fixed plate 64 and a slide plate 65. The slide plate 65 is configured to be slidable in the vehicle-width direction (Y-axis direction) by a slide mechanism 66 provided to the fixed plate 64. For example, the slide mechanism 66 may include a roller. This enables extension/contraction of the width of the left retaining plate 43L (retaining plate 43) in the vehicle-width direction (Y-axis direction). The slide plate 65 is provided with a holding hole 67 at an end of the slide plate 65 closer to the left side plate 40L in the vehicle-width direction (Y-axis direction). The holding hole 67 is for holding the left linker 60L when the side portion 61a of the left linker 60L is inserted into the holding hole 67. For this purpose, the holding hole 67 has a size that enables insertion of the side portion 61a of the left linker 60L. For example, the holding hole 67 may be a hole longer in the vertical direction (Z-axis direction). Also, a holding plate 69a is attached to the slide plate 65. The holding plate 69a is attached to the slide plate 65 at a predetermined distance from the holding hole 67 on a side opposite to the left side plate 40L across the holding hole 67 in the vehicle-width direction (Y-axis direction). The holding plate 69a is attached to the slide plate 65 through welding or the like such that a flat plane of the holding plate 69ais directed in the axis direction of the side portion 61a. The holding plate 69a is provided with a holding hole 69b. The holding hole 69b is for holding the left linker 60L when the side portion 61a of the left linker 60L is inserted into the holding hole 69b. For this purpose, the holding hole 69b has a size that enables insertion of the side portion 61a of the left linker 60L. Also, the stopper 68 provided to the side portion 61a of the left linker 60L has a shape that cannot pass through the holding hole 69b.

[0092]By insertion of the side portion 61a into the holding holes 67 and 69b, the left linker 60L is attached to the left retaining plate 43L and retained to be slidable in the vehicle-width direction (Y-axis direction). Here, the left linker 60L is retained in the left retaining plate 43L to be rotatable about the side portion 61a serving as a rotation axis.

[0093]Also, as illustrated in FIG. 6A, the left linker 60L is attached to the left side plate 40L to sandwich the left side plate 40L between the two fixing plates 62a and 62b. Therefore, the distance between the two fixing plates 62a and 62b is greater than the thickness of the left side plate 40L sandwiched between the fixing plates 62a and 62b. Also, as illustrated in FIG. 6B, the two fixing plates 62a and 62b are mounted on the lateral surface of the mounting cylinder 63 provided to the left side plate 40L. Therefore, the length of the side portion 61b of the left linker 60L is such that the side portion 61b does not contact the left side plate 40L as illustrated in FIG. 6A, i.e., the two fixing plates 62a and 62b are mounted on the lateral surface of the mounting cylinder 63 in a state in which the side portion 61a is retained by the left retaining plate 43L. Note that, rather than attaching the two fixing plates 62a and 62b to the side portion 61b through welding alone or the like, portions of the end sides of the two fixing plates 62a and 62b contacting the mounting cylinder 63 may be connected via a plate. In this case, the plate connecting the fixing plates 62a and 62b connects the fixing plates 62a and 62b at positions that do not contact the left side plate 40L.

[0094]In this manner, the left side plate 40L and the left retaining plate 43L are connected via the left linker 60L. Similarly, the right side plate 40R and the right retaining plate 43R are connected via the right linker 60R.

[0095]Next, effects provided by the linker 60 will be described.

[0096]FIGS. 7 and 8 are diagrams describing the effects provided by the linker 60 according to the present embodiment.

[0097]As described above, the side plates 40 are attached to the outer ends of the extendible/contractible screeds 31 in the vehicle-width direction. Specifically, the left side plate 40L is attached to the outer end of the left extendible/contractible screed 31L in the vehicle-width direction, and the right side plate 40R is attached to the outer end of the right extendible/contractible screed 31R in the vehicle-width direction. Also, as described above, the linkers 60 are attached to the side plates 40 and the retaining plates 43. Specifically, the left linker 60L is attached to the left side plate 40L and the left retaining plate 43L. Also, the right linker 60R is attached to the right side plate 40R and the right retaining plate 43R.

[0098]Thus, the linkers 60 connect the extendible/contractible screeds 31 and the retaining plates 43. Specifically, as illustrated in FIG. 7, the left linker 60L connects the left extendible/contractible screed 31L and the left retaining plate 43L. The right linker 60R connects the right extendible/contractible screed 31R and the right retaining plate 43R.

[0099]In this state, for example, when the left extendible/contractible screed 31L extends in a direction 4013 in FIG. 8 from the state illustrated in FIG. 7, and the width of the screed 3 extends, the left side plate 40L moves in a direction 4014 in FIG. 8. Here, the left linker 60L is attached to the left side plate 40L. The left linker 60L is attached to the left side plate 40L such that the two fixing plates 62a and 62b, which are attached to the side portion 61b, face each other in the vehicle-width direction (Y-axis direction) and sandwich the left side plate 40L.

[0100]Also, the left linker 60L is attached to the slide plate 65 of the left retaining plate 43L to be slidable in the vehicle-width direction (Y-axis direction).

[0101]Therefore, when the left side plate 40L moves in the direction 4014 in FIG. 8, the left linker 60L slides, in the direction 4014 in FIG. 8, relative to the slide plate 65 of the left retaining plate 43L.

[0102]Subsequently, when the stopper 68 provided to the side portion 61a of the left linker 60L contacts the holding plate 69a provided to the slide plate 65, the left linker 60L cannot slide anymore in the direction 4014 in FIG. 8 relative to the slide plate 65 because the stopper 68 has a shape that cannot pass through the holding hole 69b provided in the holding plate 69a.

[0103]With the configuration in which the slide plate 65 is slidable in the vehicle-width direction (Y-axis direction) relative to the fixed plate 64, the slide plate 65 is pulled, by the left linker 60L, outward (+Y side) in the vehicle-width direction (Y-axis direction) to slide in a direction 4015 in FIG. 8. This extends the width of the left retaining plate 43L in the vehicle-width direction (Y-axis direction).

[0104]In this manner, the width of the left retaining plate 43L in the vehicle-width direction (Y-axis direction) is extended in conjunction with, via the left linker 60L, the extension of the width of the left extendible/contractible screed 31L in the vehicle-width direction. Similarly, the width of the right retaining plate 43R in the vehicle-width direction (Y-axis direction) is extended in conjunction with, via the right linker 60R, the extension of the width of the right extendible/contractible screed 31R in the vehicle-width direction. Note that it may be possible to provide a stopper configured, when the stopper 68 provided to the side portion 61a of the left linker 60L contacts the holding plate 69a of the slide plate 65, to stop the left linker 60L from sliding relative to the slide plate 65 in a direction opposite to the direction 4014 in FIG. 8. Thus, the width of the left retaining plate 43L in the vehicle-width direction (Y-axis direction) can be contracted in conjunction with, via the left linker 60L, the contraction of the width of the left extendible/contractible screed 31L in the vehicle-width direction. The right linker 60R can have the same configuration.

[0105]In this manner, the width of the left retaining plate 43L in the vehicle-width direction (Y-axis direction) can be extended/contracted in conjunction with, via the left linker 60L, the extension/contraction of the width of the left extendible/contractible screed 31L in the vehicle-width direction. Similarly, the width of the right retaining plate 43R in the vehicle-width direction (Y-axis direction) can be extended/contracted in conjunction with, via the right linker 60R, the extension/contraction of the width of the right extendible/contractible screed 31R in the vehicle-width direction.

[0106]Thus, in the present embodiment, the retaining plates 43 are configured to be extendible/contractible in the widths of the retaining plates 43 in the vehicle-width direction in conjunction with, via the linkers 60, the extension/contraction of the widths of the extendible/contractible screeds 31 in the vehicle-width direction. This can extend the width of the retaining plate 43 in a simple configuration.

[0107]Also, in the present embodiment, the linkers 60 are attached to the side plates 40 and the retaining plates 43, thereby connecting the extendible/contractible screeds 31 and the retaining plates 43. This can connect the extendible/contractible screeds 31 and the retaining plates 43 in a simple configuration.

[0108]Also, in the present embodiment, in response to extension of the widths of the extendible/contractible screeds 31 in the vehicle-width direction, the retaining plates 43 are pulled, by the linkers 60, outward in the vehicle-width direction, and the widths of the retaining plates 43 in the vehicle-width direction are extended. This can connect the extendible/contractible screeds 31 and the retaining plates 43 in a simple configuration.

[0109]Next, a method of housing the linkers 60 will be described.

[0110]FIGS. 9 and 10 are diagrams describing a method of housing the linkers 60 according to the present embodiment.

[0111]As described above, the left linker 60L is retained in the left retaining plate 43L to be rotatable about the side portion 61a serving as a rotation axis. Also, in a state in which the left linker 60L is attached to the left side plate 40L, the two fixing plates 62a and 62b provided to the side portion 61b are mounted on the lateral surface of the mounting cylinder 63 to sandwich the left side plate 40L.

[0112]Therefore, as illustrated in FIG. 9, the left linker 60L can be rotated, in a direction 4016 in FIG. 9, about the side portion 61a serving as the rotation axis. This achieves a state in which the left side plate 40L is not sandwiched between the two fixing plates 62a and 62b. Thus, the left linker 60L can be removed from the left side plate 40L by a simple operation of rotating the left linker 60L, in the direction 4016 in FIG. 9, about the side portion 61a serving as the rotation axis.

[0113]Thus, in the present embodiment, the linkers 60 are attached to the side plates 40 to be removable. By this, in accordance with requirements depending on a type of work or the like, it is possible to allow the width of the retaining plate 43 not to be in conjunction with the widths of the extendible/contractible screeds 31.

[0114]Also, as described above, by insertion of the side portion 61a into the holding holes 67 and 69b, the left linker 60L is attached to the left retaining plate 43L and retained to be slidable in the vehicle-width direction (Y-axis direction).

[0115]Therefore, as illustrated in FIG. 10, after removal of the left linker 60L from the left side plate 40L as illustrated in FIG. 9, the left linker 60L can slide in a direction 4017 in FIG. 10. Here, as described above, when the stopper configured to stop the left linker 60L from sliding relative to the slide plate 65 in the direction opposite to the direction 4014 in FIG. 8 is provided, removal of that stopper or the like is performed.

[0116]In this manner, the left linker 60L can be housed in the left retaining plate 43L. Thus, in the present embodiment, the linkers 60 are configured to be housed in the retaining plates 43. This can avoid interference of the linkers 60 with work performed behind the retaining plate 43, e.g., work to extend the screws SC.

[0117]Note that, rather than sliding the linkers 60, the linkers 60 may be configured to be housed in the retaining plates 43 through folding or the like. However, when the linkers 60 are configured to be housed in the retaining plates 43 by sliding inward in the vehicle-width direction (Y-axis direction), it is possible to reduce a work space when housing the linkers 60 in the retaining plates 43.

[0118]Also, in the present embodiment, the linkers 60 each have an L shape, one side of the L shape is attached to the retaining plate 43 to be slidable, and the other side of the L shape is attached to the side plate 40 to be removable. By this, the linkers 60 can be readily configured in accordance with the distances between the retaining plates 43 and the side plates 40 in the vehicle-width direction (Y-axis direction), and the distances between the retaining plates 43 and the side plates 40 in the vehicle-length direction (X-axis direction).

[0119]When attaching the linker 60 housed in the retaining plates 43 to the side plate 40, a reverse operation of the above operation may be performed.

[0120]Specifically, first, the linker 60 is allowed to slide in the vehicle-width direction (Y-axis direction), and pulled out from the retaining plate 43. Subsequently, the linker 60 is allowed to rotate about the side portion 61a serving as the rotation axis, thereby mounting the two fixing plates 62a and 62b on the mounting cylinder 63 from above such that the side plate 40 is sandwiched between the two fixing plates 62a and 62b.

[0121]Thus, the linker 60 housed in the retaining plate 43 can be attached to the side plate 40.

[0122]Next, effects when the height or inclination of the screeds 3 changes will be described.

[0123]As described above, the screed 3 of the asphalt finisher 100 of the present embodiment is moved upward or downward along with the leveling arms 3A due to the extension/contraction of the screed lift cylinders 25. Also, the inclination of the screed 3 can change due to the extension/contraction of the leveling cylinders 23.

[0124]FIGS. 11 and 12 are diagrams describing effects when the height of the screed 3 changes.

[0125]When the left linker 60L is attached to the left side plate 40L, the left side plate 40L is sandwiched between the two fixing plates 62a and 62b. In addition, as illustrated in FIG. 11, the two fixing plates 62a and 62b are mounted on the lateral surface of the mounting cylinder 63 provided to the left side plate 40L.

[0126]Also, the left linker 60L is retained by the left retaining plate 43L to be rotatable about the side portion 61a serving as the rotation axis.

[0127]Here, in a state in which the left linker 60L is attached to the left side plate 40L, the lateral surface of the mounting cylinder 63 on which the two fixing plates 62a and 62b are mounted is a cylindrical surface. Therefore, when the left side plate 40L moves in a direction 4021 in FIG. 12 as the screed 3 increases in height, if the left linker 60L can rotate about the side portion 61a serving as the rotation axis, the two fixing plates 62a and 62b can move on the lateral surface of the mounting cylinder 63 while changing contact portions of the two fixing plates 62a and 62b with the lateral surface of the mounting cylinder 63.

[0128]Accordingly, when the left side plate 40L moves in the direction 4021 in FIG. 12 as the screed 3 increases in height, the left linker 60L can rotate about the side portion 61a, serving as the rotation axis, in a direction 4022 in FIG. 12, and the two fixing plates 62a and 62b can move on the lateral surface of the mounting cylinder 63 while changing the contact portions of the two fixing plates 62a and 62b with the lateral surface of the mounting cylinder 63. By rotation of the left linker 60L about the side portion 61a, serving as the rotation axis, in the direction 4022 in FIG. 12, and by movement of the two fixing plates 62a and 62b on the lateral surface of the mounting cylinder 63 while changing the contact portions of the two fixing plates 62a and 62b with the lateral surface of the mounting cylinder 63, the left retaining plate 43L does not move along with the left side plate 40L in the direction 4021 in FIG. 12.

[0129]Similarly, when the screed 3 decreases in height, the left linker 60L rotates about the side portion 61a, and thus the left retaining plate 43L does not move in the same direction as does the left side plate 40L.

[0130]Similarly, when the inclination of the screed 3 changes, the left linker 60L rotates about the side portion 61a, and thus the height of the left retaining plate 43L does not change.

[0131]As described above, in the present embodiment, the lateral surface of the mounting cylinder 63 on which the two fixing plates 62a and 62b of the linker 60 are mounted is a cylindrical surface. Here, the mounting cylinder 63 is an example of a mounting portion on which the linker 60 is to be mounted. The mounting cylinder 63 has a structure configured to retain the left linker 60L to be rotatable about the side portion 61a. With this configuration, even if the height or inclination of the screed 3 changes, it is possible to avoid change in the height of the left side plate 40L.

[0132]Also, the asphalt finisher 100 can be set such that the screed 3 is high at the center portion in the vehicle-width direction (Y-axis direction) and low at both ends in the vehicle-width direction (Y-axis direction). This is for providing the road surface with a slightly arch gradient, thereby facilitating flowing of water toward both sides of the road, for example, when it rains. When the height of the screed 3 is set in this manner, the side plate 40 sandwiched between the two fixing plates 62a and 62b is not parallel to the two fixing plates 62a and 62b, but is inclined obliquely.

[0133]Therefore, the distance between the two fixing plates 62a and 62b can be made wider, with a predetermined margin, than the thickness of the side plate 40 sandwiched between the fixing plates 62a and 62b. In this case, the two fixing plates 62a and 62b may be welded to the side portion 61b via spacers. Also, portions of the end sides of the two fixing plates 62a and 62b contacting the mounting cylinder 63 may be connected via a plate. Thus, even if the side plate 40 is inclined obliquely relative to the two fixing plates 62a and 62b, the side plate 40 can be sandwiched between the two fixing plates 62a and 62b.

[0134]Although the embodiments have been described above in detail, the present disclosure is not limited to these specific embodiments, and various modifications and alterations are possible within the scope of the intent of claims recited.