JPH0252042B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a pavement thickness measuring device installed in a leveling machine such as an asphalt finisher or a base paver.

``Prior Art'' As is well known, in an asphalt finisher, while a vehicle is running, asphalt mixture (paving material) is fed into a hopper provided on the vehicle and is transferred to a rear screw through a pair of left and right feeders. Here, it is spread evenly from side to side, and then spread evenly with a screed.

By the way, when paving roads with a leveling machine such as the above-mentioned asphalt finisher, if the pavement thickness becomes thinner than the design value, the pavement strength becomes weaker, and conversely, if it becomes thicker than the design value, the pavement strength becomes a problem. However, the problem is that the consumption of asphalt mixture increases, resulting in economic losses. Therefore, when paving roads, it is necessary to proceed with the work while checking from time to time whether the pavement thickness is as designed.

``Problem to be solved by the invention'' However, conventionally, the above-mentioned pavement thickness was adjusted to the target pavement thickness by a worker other than the operator who operates the leveling machine. They were checking by inserting a gauge rod into the newly constructed paved road. For this reason, at least two workers are required for one leveling machine, which is an obstacle to promoting labor savings. Further, there are problems in that not only the paved road surface that has been painstakingly constructed is damaged, but also that the thickness of the pavement cannot be continuously checked, and furthermore, this checking process itself requires skill. Therefore, it may be possible to equip the leveling machine with a device that measures the pavement thickness by contacting the road surface without damaging it, but in this case, asphalt that has spilled on the road surface may be removed. If there is exposed material or crushed stone, there are problems such as the inability to accurately measure pavement thickness, and the possibility that the detection part of the measuring device may be damaged by obstacles.

The present invention was made in view of the above circumstances, and
The purpose of this is to ensure that the measured values do not vary due to the influence of the paved road surface, and that the pavement thickness can be measured automatically and reliably and continuously, making it possible to speed up paving work and save labor. An object of the present invention is to provide a pavement thickness measuring device for a leveling machine.

"Means for Solving the Problems" In order to achieve the above object, the present invention applies paving material to the road surface based on the top surface of the crawler links of endlessly connected crawler devices that are in contact with the road surface. It is equipped with a height detector that detects changes in the height of the screed to be leveled, and an arithmetic device that calculates pavement thickness based on the output of the height detector.

"Operation" In the pavement thickness measuring device of the present invention, based on the change in the height of the screed with respect to the top surface of the crawler link that is in contact with the road surface, detected by the height detector, The pavement thickness is automatically calculated in the calculation device.

"Embodiment" Hereinafter, a first embodiment of the present invention will be described based on FIGS. 1 to 6.

Reference numeral 1 in the figure indicates the vehicle body of the Asphalt Finisher AF, and a pair of left and right crawler devices 2 are disposed at the bottom of the vehicle body 1. These crawler devices 2 each have a support shaft 3 and a drive shaft 4 disposed in the front and rear, and a pair of front and rear guide rollers 5 each having two guide rollers 5, 5 installed between these shafts 3, 4. It consists of devices 6 and 7 and a plurality of crawler links 8 which are connected in an endless manner and stretched around the respective shafts 3 and 4 and the guide roller 5, and are installed inside the vehicle body 1. The rotation of the engine is transferred from the gearbox to the intermediate shaft,
By being transmitted to the drive shaft 4 via the chain,
An endless crawler link 8 revolves around each shaft 3, 4 and a guide roller 5, so that the asphalt finisher AF travels. Also,
A hopper 9 is installed at the front of the vehicle main body 1, and the asphalt mixture fed into the hopper 9 is fed to a pair of left and right feeders (not shown).
By this means, it is conveyed to a position in front of a pair of left and right screws 10 arranged at the rear of the vehicle body 1. A pair of leveling arms 11 are provided on both sides of the vehicle body 1 so as to be able to swing up and down in a vertical plane along the longitudinal direction of the vehicle body 1 about each pivot shaft 12. A pair of screeds 13 are suspended from the rear end of the arm 11 and are extendable left and right. Furthermore, the tips of the rods of a pair of left and right screed cylinders 14 whose base ends are rotatably connected to the upper rear end of the vehicle body 1 are rotatably connected to the rear end of each leveling arm 11. By operating these screed cylinders 14, each screed 13 can be moved up and down about each of the pivot shafts 12, and
Each screed cylinder 14 is in a state in which it can freely expand and contract without applying pressure oil during paving work. And the above asphalt finisher
The AF is equipped with a pavement thickness measuring device to automatically measure the pavement thickness t.

The above pavement thickness measuring device, as shown in Fig. 2,
A height detector 15 detects changes in the height of the screed 13 with the upper surface 8a of the crawler link 8 whose lower surface is in contact with the road surface as a reference, and the pavement is determined based on the signal from the height detector 15. A pavement thickness calculation unit 16 that calculates the thickness t, and a pavement thickness display device 17 that displays the pavement thickness t obtained by the pavement thickness calculation unit 16.
It is composed of.

As shown in FIGS. 3 to 5, the height detector 15 includes a box 19 fixed to the front end of a support member 18 whose rear end is fixed to the screed 13;
A rotating shaft 21 is rotatably and horizontally attached to the box 19 via a bearing 20, and an arm 23 has an upper end fixed to one end of the rotating shaft 21 and a rotatable caster 22 at a lower end. ,
A bellows coupling 2 is attached to the other end of the rotating shaft 21.
When the caster 22 is made to run on the upper surface 8a of the crawler link 8 which is in contact with the road surface, the arm 23 moves up and down and the rotating shaft 21 rotates. However, the rotation angle θ is detected by the potentiometer 25 as an electric signal.

Further, the height detector 15 is connected to an A/D converter (analog-digital converter) 26 of the pavement thickness calculation section 16.
6 converts the detection signal (analog signal) of the height detector 15 into a digital signal and inputs it to the arithmetic unit 27. This arithmetic unit 27 includes a ROM (read-only memory) 28
A and a RAM (read/write memory) 28b are connected to a storage device 28, and the arithmetic unit 27 calculates the relationship stored in advance in the storage device 28 based on the detected value of the height detector 15. The pavement thickness t is calculated using the formula. This relational expression is obtained as follows.

That is, in FIG. 6, the length of the arm 23 is l, the standard pavement thickness is t ₀ (for example, 50 mm), the angle between the arm 23 and the vertical line when the standard pavement thickness is t ₀ is θ ₀ , and If the angle between the arm 23 and the vertical line is θ = θ ₀ −dθ when the pavement thickness is arbitrary t = t ₀ + dt, then the change in pavement thickness dt is the change in the cosine component (vertical component) of the arm 23. t−t ₀ =lcosθ−lcosθ ₀ Therefore, dt=lcos(θ ₀ −dθ)−lcosθ ₀ =l{cos(θ ₀ −dθ)−cosθ ₀ }. Therefore, if the length l, angle θ ₀ , and reference pavement thickness t ₀ are stored in advance in the storage device 28, the change in pavement thickness dt and the pavement thickness t can be determined.

Furthermore, the pavement thickness display device 17 is connected to the calculation device 27 via a driver circuit 29 . This pavement thickness display device 17 is composed of a liquid crystal (LCD), and the pavement thickness calculation section 16
The pavement thickness t obtained in the above is digitally displayed.

With Asphalt Finisher AF incorporating the pavement thickness measuring device configured as above,
When paving a road with asphalt, as in the past, while the vehicle body 1 is running at a constant speed,
The asphalt mixture put into the hopper 9 is sent to the screed 10 by a feeder (not shown) and uniformly supplied to the front part of the screed 13. As a result, the screed 13 is pushed upward by the resistance of the asphalt mixture, and the asphalt mixture is compressed by the weight of the screed 13 itself, but the resistance is balanced with the weight of the screed 13. The inclination state of each leveling arm 11 is determined, the attack angle α of the screed 13 is determined, and the asphalt mixture is spread on the road with a required paving thickness t.

At this time, the worker must proceed with the work while checking whether the above-mentioned pavement thickness t has reached the set value, but in the above-mentioned asphalt finisher AF, this pavement thickness t is automatically set. Measured continuously. That is, the height detector 15 detects the angle θ between the arm 23 and the vertical line.
Then, this detected value is sent to the arithmetic unit 27 via the A/D converter 26 to calculate the pavement thickness t based on the above-mentioned relational expression, and is sent to the pavement thickness display device via the driver circuit 29. 17 is digitally displayed. The worker only has to proceed with the paving work while checking the displayed value of the pavement thickness t, which eliminates the inefficient work of measuring the pavement thickness by sticking a gauge rod into the constructed pavement. This makes it possible to speed up paving work and save labor. In addition, the height detector 15 is configured such that the caster 22 provided at the lower end of the arm 23 runs on the upper surface 8a of the crawler link 8 that is in contact with the road surface, so that no spillage occurs on the road surface. Even if asphalt composite material or crushed stone is exposed, stable measurement values can be obtained without being affected by these, and the height detector 15 will not be damaged by obstacles on the road. Improved reliability of measurements.

Further, in the first embodiment, the height detector 15 using the potentiometer 25 was explained, but as shown in FIG. 7, instead of the height detector 15, a capacitor A non-contact distance measuring device 30 that uses a magnetic field, ultrasonic waves, a high-frequency magnetic field (proximity switch), etc. is attached to the front end of the support member 18 so as to face the upper surface 8a of the crawler link 8 that is in contact with the road surface. Good too. In this case, the non-contact distance measuring device 30 detects the distance from the top surface 8a of the crawler link 8 that is in contact with the road surface.
Based on the change in distance ds from the reference value, the pavement thickness t can be determined by t=t ₀ +ds.If this relational expression is stored in the storage device 28, the pavement thickness t can be calculated as follows. It is automatically and continuously calculated by the arithmetic unit 27.

"Effects of the Invention" As explained above, the present invention provides a method for determining the height of a screed for leveling paving material on a road surface, with the top surface of the crawler links in contact with the road surface of endlessly connected crawler devices as a reference. Since it is equipped with a height detector that detects a change in the height and a calculation device that calculates the pavement thickness based on the output of the height detector,
The pavement thickness is calculated by the computing device based on the change in the height of the screed with respect to the top surface of the crawler link that is in contact with the road surface, which is detected by the height detector. This simplifies the management and paving work, speeds up the work, and saves labor.In addition, the height detector does not have asphalt mixture spilled on the road surface acting as a disturbance, and the height Since the detector is not damaged by obstacles on the road, it has the excellent effect of improving the reliability of the measured value of pavement thickness.

[Brief explanation of the drawing]

1 to 6 show a first embodiment of the present invention, in which FIG. 1 is a side view of an asphalt finisher, FIG. 2 is a schematic configuration diagram, and FIGS.
The figure shows the height detector, and the third figure is a plan view.
FIG. 4 is a side view, FIG. 5 is a sectional view, FIG. 6 is an explanatory diagram illustrating a formula for calculating pavement thickness, and FIG. 7 is an explanatory diagram showing a second embodiment of the present invention. 1...Vehicle main body, 2...Crawler device, 8...
Crawler link, 11...Leveling arm, 1
3...Screed, 15...Height detector, 27...
...Arithmetic device, 8a...Top surface, 30...Non-contact distance measuring device (height detector).

Claims (1)

[Claims] 1 A crawler device 2 formed by connecting a plurality of crawler links 8 in an endless manner is provided on the vehicle body 1, and a leveling arm 11 is provided on the vehicle body 1 to swing within a vertical plane along the longitudinal direction of the vehicle body 1. In a pavement thickness measuring device for a leveling machine, which is freely attached to the leveling arm 11 and is provided with a screed 13 for leveling the paving material on the road surface, the upper surface 8a of the crawler link 8 that is in contact with the road surface is measured. The above screed 1 is used as a standard.
Height detectors 15, 30 detecting changes in height of 3.
1. A pavement thickness measuring device for a leveling machine, comprising: and a calculation device 27 that calculates pavement thickness based on the outputs of the height detectors 15 and 30.