JPH0230486Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a pavement thickness control device for an asphalt finisher.

(Prior Art) A conventional asphalt finisher will be explained with reference to FIG. 6. 1 is a hopper attached to the front of the car body 3, 2 is a bar conveyor device provided inside the car body 3, and 4 is a hopper attached to the front of the car body 3.
is a screw conveyor installed on the vehicle body 3, 5 is a screed device, 7 is a side arm, and 13' is a lift cylinder. It is pivoted to enable rotation.
13 is a leveling cylinder attached to the vehicle body 3 in a suspended state, and the lower end of the leveling cylinder 13 and the piston rod are connected to the side frame 7.
is pivotally supported via a pin 6 at the front end of. 8 is the thickness handle (pavement thickness adjustment device),
N is an unpaved uneven roadbed, M is a paved roadbed, Hoppa 1
The asphalt mixture supplied to the screeding device 2 is conveyed to the screw conveyor 4 at the rear of the vehicle body 3, and the asphalt mixture is spread from the screw conveyor 4 to the unpaved uneven roadbed N in front of the screeding device 5. It is spread and formed into a pavement M having a required pavement thickness T by the screeding device 5 as the vehicle body 3 moves forward. As a method for forming this pavement body M, a method called floating screed is usually adopted. In this forming method, when the screed device 5, which is propelled in the vertical direction by a side frame 7 that is supported so as to be able to rotate vertically around a pivot point 6 in the vehicle body 3, has a working angle α, the screed's own weight, The screed device 5 is held in an equilibrium state by the material resistance and traction force, and a flat pavement M having a required thickness T is formed. If any one of these four factors changes: the working angle α, the screed's own weight, the material resistance, and the traction force, the equilibrium state of the screed device 5 will collapse, the pavement thickness T will increase or decrease, and the surface of the pavement M will deteriorate. do. Correcting the pavement thickness T once the equilibrium state has been disrupted, or controlling the pavement thickness T when changing the set pavement thickness during construction, is usually done by rotating the thickness handle (pavement thickness adjustment device) 8. Let the working angle α
This is done by changing the

In addition, a leveling control system that automatically controls the pavement thickness T is adopted, but this system moves the pivot point 6 up and down instead of the thickness handle 8 to adjust the working angle α. By changing the pavement thickness T
This system is explained with reference to Figs. 7 and 8. Reference numeral 9 is an ideal reference line that is different from the unpaved uneven roadbed N on which the finisher runs. etc., and the deviation between this ideal reference line 9 and the screed is detected by a rotary grade sensor 10 installed on the side frame. This rotary grade sensor 10 has an arm that converts the amount by which the screed moves up and down with respect to the ideal reference line 9 into a rotation angle, and outputs an electrical control signal 11 according to this rotation angle. It has a function. This control signal 11 is sent to the valve 12 of the pressure fluid supply/discharge system of the leveling cylinder 13 to operate the leveling cylinder 13 in the expansion/contraction direction. This moves the pivot point 6 up and down, and the side arm 7
The working angle α of the screed device 5 is changed by rotating the screed device 5 in the vertical direction about the pivot point with the lower end of the piston rod of the lift cylinder 13', thereby modifying the pavement thickness T. On the other hand, regarding the lateral slope, the slope sensor 15 detects the deviation between the actual lateral slope and the set lateral slope, converts it into an electrical output signal, sends it to the valve 12, and sends it to the leveling cylinder. 13
is actuated in the expansion/contraction direction to control the actual lateral gradient to the set lateral gradient. The series of operations described above are continued until the detected values of the rotary grade sensor 10 and the slope sensor 15 match the ideal reference line 9 or the set lateral slope, and are always in line with the ideal reference line 9 and the set lateral slope. A parallel pavement M is obtained.

(Problem to be solved by the invention) In the asphalt finishing shown in FIG. Penetrate, visually observe the amount of penetration,
The pavement thickness T is measured and checked, and the pavement thickness T is corrected while predicting changes in the unevenness of the unpaved uneven roadbed N, and the flatness of the pavement M and pavement thickness accuracy are At the same time, it is necessary to manage
Management operations are extremely complicated. Furthermore, since this management operation is performed outdoors in a bad environment, the workers are extremely fatigued, which adversely affects the accuracy of the paved surface finish.
Furthermore, because the work is carried out in poor conditions, it is difficult to secure skilled workers, and wages are rising.

Furthermore, the leveling control system shown in FIGS. 7 and 8 had the following problem. That is, (i) it is a system that attempts to form a paved surface parallel to a reference plane consisting of a set reference line and cross slope, and does not have a function to measure or control the pavement thickness T. (ii) Changes in pavement thickness T resulting from the difference between the set reference plane and the roadbed unevenness are detected by visually measuring the amount of gauge penetration, and a full-time worker is required to constantly check for thickness changes and make corrections. become. (iii) The accuracy of measurement and correction of thickness depends on the skill level of full-time workers, and there is a limit to improving the accuracy and saving labor of paving work.

The present invention has been proposed in view of the above-mentioned problems, and its purpose is to simplify the structure and reduce manufacturing costs. Another object of the present invention is to provide an asphalt pavement thickness control device that can perform highly accurate measurement.

(Means for Solving the Problems) In order to achieve the above object, the present invention includes a side frame that can be rotated in the vertical direction centering on the front and rear intermediate portions, and a lower end of the piston rod at the front end of the side frame. A pivoted leveling cylinder,
In an asphalt finisher having a screed device suspended and supported on the rear end side of the side frame, a front sled attached to the front part of the vehicle body;
a rear sled attached to the rear of the vehicle body; a first tilting liquid level gauge and a second tilting liquid level gauge that are erected on the front sled and whose bottoms communicate with each other through a pipe; and a second tilting liquid level gauge on the rear sled. and a first reference liquid level gauge and a second reference liquid level gauge which were erected on the front sled and whose bottoms were connected to each other by a flexible pipe, and which were attached to the upper part of each of the liquid level gauges. A plurality of displacement gauges and a signal processing device that calculates a control signal to keep the pavement thickness constant based on the level detection signals from each of the displacement gauges and sends it to a valve of a pressure fluid supply and discharge system of the leveling cylinder. It is equipped with

(Function) The asphalt finisher pavement thickness control device of the present invention is configured as described above, and the asphalt mixture supplied to the hopper is spread through the conveyor device onto the unpaved uneven roadbed in front of the screed device. At the same time, the leveling cylinder is operated in the expansion and contraction direction, and the side frame and screed device are raised and lowered around the front end of the side frame, and the required thickness of paving is achieved using the screed's own weight, mixture resistance, and traction force. Shape your body. At this time, the front sled is slid on the unpaved road surface and the rear sled is slid on the paved surface, while the first reference liquid level gauge on the rear sled and the second reference liquid level gauge on the front sled are connected. The liquid level height with respect to the first and second tilting liquid level gauges on the front sled is detected by displacement gauges installed on each side, and the level detection signal obtained at this time is sent to the signal processing device. It calculates and processes a control signal to keep the pavement thickness constant, and sends it to the valve in the pressure fluid supply and discharge system of the leveling cylinder.
The leveling cylinder is operated in the extending and retracting direction, the side arm is rotated in the vertical direction, and the angle of the side arm is changed to balance the lift force on the screed device caused by the operating angle between the screed device and the paving body and the weight of the screed device. At the same time, the thickness of the pavement is maintained at a predetermined value.

(Embodiment) Next, the asphalt finisher pavement thickness control device of the present invention will be explained using an embodiment shown in FIGS. 1 to 5. In FIG. A screw conveyor 4 is provided inside, 5 in FIGS. 1 and 5 is a screed device, 7 is a side arm, and the screed device 5 is attached to the rear end of the side arm 7. Also 13
is a leveling cylinder mounted in a suspended state on the vehicle body 3; 6 is a pivot point for pivotally supporting the lower end of the piston rod of the leveling cylinder 13 and the front end of the side arm 7; 16 in FIG. 2 is a level measuring device; In FIGS. 1 to 4, 31 is a front sled that slides on an unpaved uneven roadbed N, 32 is a link that connects the front sled 31 and the vehicle body 3, and 33
is a rear sled that slides on the pavement body M; 34 is a link that connects the rear sled 33 and the vehicle body 3; 35
is the case of the level measuring device 16 installed on the front sled 31, and 36 is the case of the first reference liquid level meter 46 installed on the rear sled 33. A non-contact displacement meter with a float, 39, is a second reference liquid level meter, 4, which is installed upright inside the case 35 of the level measuring device 16.
0, 41 are the first and second slope liquid level gauges installed upright in the case 35 of the same level measuring device 16, 43
is a non-contact displacement meter with a float installed on the first liquid level meter 40 for tilting, 44 is a non-contact displacement meter with a float installed on the second liquid level meter 41 for tilting, and 45 is the second non-contact displacement meter with a float installed on the second liquid level meter 41 for tilting. A non-contact displacement meter with a float installed on the reference liquid level meter 39; 38 is a pipe connecting the bottoms of the reference liquid level meter 36 and the liquid level meter 39; 37 is the same pipe 38;
A flexible pipe 42 inserted in the middle of the first
A pipe 47 connecting the bottoms of the tilting liquid level meter 40 and the second tilting liquid level meter 41 is the non-contact displacement meter 43, 44, 45 with a float.
46, the non-contact displacement meters with floats 43, 44, 45, 46 detect the height position of the float at the liquid level in each of the liquid level meters 36, 39, 40, 41. Then, the level detection signal obtained at that time is sent to the signal processing device 47. These non-contact displacement meters with floats 43, 44, 45, and 46 have a magnet attached to the float, and the height position of this float is detected by a magnetostrictive displacement meter. The detection may be performed using an ultrasonic displacement meter. This magnetostrictive displacement is an application of the magnetostrictive phenomenon caused by the Widemann effect, and the magnet in the float that moves along the sensor probe generates torsional strain on the special magnetostrictive wire in the probe. This is an absolute displacement meter that detects the position of a magnet, that is, a float, by measuring propagation time. Moreover, an electric inclinometer may be used instead of the liquid level gauges 40 and 41 for inclination.

Next, the operation of the asphalt finisher pavement thickness control device shown in FIGS. 1 to 5 will be explained in detail.

First, the level measuring device 16 will be explained.
FIG. 3 shows a case where the unpaved uneven roadbed N has no slope. The front sled part 31 is slid on an unpaved uneven roadbed N, and the rear sled part 33 is slid on a paved body M. In this case, the first reference liquid level meter 36 on the rear sled section 33 moving on the pavement M
and the second reference liquid level meter 3 on the front sled section 31 moving on the unpaved uneven roadbed N.
The relationship between 9 and the liquid level height l20 is l10+T=l20=l30
= l40. At this time, these liquid level gauges 3
The non-contact displacement meters 45 and 46 with floats that detect the liquid level of 6 and 39 indicate a constant level even if there is sloshing etc. within the non-contact displacement meters 45 and 46 due to the inertia of the float. . In addition, a pipe 38 and a flexible pipe 37 connect the bottoms of the first and second reference liquid level gauges 36 and 39.
Even if the liquid level changes due to deformation, l10+
Δl10+T=l20+Δl20 (Δl10=Δl20), and T
The value of does not change. In addition, a magnetostrictive wire type displacement meter is used as the non-contact displacement meter with a float, so there are fewer electronic parts, and it is possible to obtain a very stable output with excellent vibration resistance and temperature characteristics, reducing costs.

FIG. 4 shows a case where an unpaved uneven roadbed N has an inclination angle θ. In this case, the pavement M
The liquid level of the first reference liquid level gauge 36 on the rear sled section 33 that moves on the upper surface is l11, and the second reference liquid level on the front sled section 31 that moves on the unpaved uneven roadbed N. The total liquid level height of 39 is l21, and the liquid level height of the first slope liquid level gauge 40 on the front sled part is
l31, and if the liquid level height of the second tilting liquid level gauge 41 on the front sled part 31 is l41, tanθl31−l41/L ₁ , l ₁₁ +T+L ₂ tanθ=l ₂₁ , and the thickness T becomes T=l ₂₁ −l ₁₁ +L ₂ (l ₃₁ +l ₄₁ )/L ₁ . Non-contact displacement meter with float 43, 44, 4
The level detection signal sent from 5, 46 to the signal processing device 47 is calculated and processed here into a control signal that keeps the pavement thickness T constant, and this is used as a control signal for the pressure fluid supply and discharge system of the leveling cylinder 13 (Fig. (not shown)
The leveling cylinder 13 operates in the direction of expansion and contraction, and the side arm 7 moves to the lift cylinder 1.
The side arm 7 rotates vertically around the pivot point with the piston rod 3', and the angle of this side arm 7 is changed, thereby adjusting the working angle α between the screed device 5 and the pavement body M.
The lifting force on the screed device 5 generated by this is balanced with the weight of the screed device 5, and the thickness T of the pavement M is maintained at a predetermined value. Also, if the thickness T of the pavement M changes for some reason during paving work, the non-contact displacement meter 4 with a float
The same effect as described above is performed by the level detection signals from 3, 44, 45, and 46.

(Effects of the invention) The asphalt finisher pavement thickness control device of the present invention has a level measuring device installed on the front sled attached to the front of the vehicle body, the rear sled attached to the rear of the vehicle body, and the above-mentioned front sled. A first slope liquid level gauge and a second slope liquid level gauge are installed upright on the sled and their bottoms communicate with each other through a pipe, and a second slope level gauge is installed upright on the rear sled and on the front sled and communicates with each other through a pipe. A first reference liquid level gauge and a second reference liquid level gauge whose bottoms are connected by a flexible pipe, a plurality of displacement gauges attached to the upper part of each of the above liquid level gauges, and a plurality of displacement gauges from each displacement gauge. It is composed of a signal processing device that calculates a control signal to keep the pavement thickness constant based on the level detection signal and sends it to the valve of the pressure fluid supply and discharge system of the leveling cylinder, simplifying the structure of the level measuring device. can be used to reduce production costs.

Furthermore, the bottoms of the first reference liquid level gauge on the rear sled and the second reference liquid level gauge on the front sled are connected by a flexible pipe, so that measurement errors due to deformation of the connecting pipe do not occur. Furthermore, even if sloshing occurs, it will not be affected by the inertia of the float. Therefore, there is an effect that highly accurate measurement can be performed.

[Brief explanation of the drawing]

Fig. 1 is a side view showing an embodiment of an asphalt finisher pavement thickness control device according to the present invention; Fig. 2 is a side view showing a level measuring device;
The figure is a side view showing a level measuring device on a flat roadbed, FIG. 4 is a side view showing a level measuring device on a sloped roadbed, FIG. 5 is a system diagram of the signal processing device,
FIG. 6 is a side view showing a conventional asphalt finisher, FIG. 7 is a perspective view showing its pavement thickness control device, and FIG. 8 is a system diagram thereof. 1... hopper, 2, 4... conveyor device, 3...
...Vehicle body, 5...Screed device, 6...Pivot point, 7...Side arm, 13...Leveling cylinder, 13'...Lift cylinder, 16...Level measuring device, 31...Front sled, 32... Link, 33... Backward sled, 34... Link, 35...
... Case of level measuring device 16, 36 ... First reference liquid level meter, 37 ... Flexible pipe, 38
... Pipe, 39 ... Second standard liquid level gauge,
40...First slope liquid level gauge, 41...Second
Inclined liquid level gauge, 42...pipe, 43,4
4, 45, 46...Non-contact displacement meter with float, 4
7...Signal processing device, M...Pavement body, N...Unpaved roadbed, T...Pavement thickness.

Claims (1)

[Scope of utility model registration request] A side frame that is rotatable in the vertical direction centering on the front and rear intermediate portions, a leveling cylinder in which the lower end of a piston rod is pivotally supported at the front end of the side frame, and a screed device that is suspended and supported on the rear end of the side frame. An asphalt finisher having a front sled attached to the front part of the vehicle body, a rear sled attached to the rear part of the vehicle body, and a first tilting liquid erected on the front sled, the bottoms of which are connected by a pipe. A surface level meter, a second liquid level meter for tilting, and a first reference liquid level meter and a second standard, which are erected on the rear sled and the front sled and whose bottoms are connected to each other by a flexible pipe. A liquid level meter, a plurality of displacement gauges attached to the top of each of the liquid level gauges, and a control signal to maintain a constant pavement thickness are calculated based on the level detection signals from each displacement gauge. A pavement thickness control device for an asphalt finisher, comprising a signal processing device that sends a signal to a valve of a pressure fluid supply and discharge system of the leveling cylinder.