JPS63150608A - Pavement thickness detector - Google Patents

Abstract

PURPOSE:To accurately measure the thickness of pavement without being affected by the state of a roadbed while facilitating setting operation by comparing variation in the height before and after a road is surfaced by using a laser beam as a reference, and calculating the thickness of the pavement. CONSTITUTION:A pavement thickness detector consists of a laser light projector 2 which projects the laser beam 3, a distance detector 4 which outputs a signal every time a finisher 1 moves forth by specific distance, and 1st and 2nd laser light photodetectors 8 and 11. The detector 4 sends out a signal at intervals of distance L and an arithmetic device (not shown in a figure) which receives this signal increases an address pointer by one to (m+1) to read Xm+1 out of a memory area while writing Xm in the memory area according to the value (m) of the address pointer at this time. Then the difference T=y-Xm+1 from the output value (y) of the photodetector 11 is computed and the difference T is displayed as the pavement thickness on a display part.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a pavement thickness detection device used in a leveling machine such as an asphalt finisher.

BACKGROUND ART When paving a roadbed with a leveling machine such as an asphalt finisher, it is necessary to perform the work while checking whether the pavement thickness is within a target value. Conventionally, a person who operates the leveling machine and a separate worker inserts a gauge rod into the pavement to check. However, this method not only damages the pavement after construction, but also
It is not possible to continuously check the pavement thickness, and the checking process itself requires skill.To deal with these problems, Japanese Patent Application Laid-Open No. 61-95103 and Japanese Utility Model Application No. 60-1
No. 72808 and the like have been proposed.

Problems to be solved by this invention However, even with these known techniques, pavement thickness is estimated based on the roadbed before paving, and if there is no continuity in the roadbed such as a difference in level, correct values cannot be obtained, and if there are irregularities in the roadbed, an accurate value cannot be obtained. However, this method had the disadvantage of directly causing measurement errors.

Therefore, the present invention improves the disadvantages of the known techniques as described above, and provides a pavement thickness detection device that is not affected by the condition of the roadbed, is easy to set up, and can measure pavement thickness with high accuracy. The purpose is to

Structure of the Invention The pavement thickness detection device according to the present invention is provided with a laser projector that projects a laser beam substantially parallel to the roadbed along the finisher movement position above the roadbed. A distance detector is installed that slides in movable displacement and outputs a signal every predetermined advance distance of the finisher, and is mounted on a shaft extending vertically upward from the distance detector to connect its own reference point and laser beam. A first laser receiver is provided to output the positional deviation from the light receiving point,
Further, on the rear side in the direction of movement of the finisher, the laser receiver is mounted on a shaft that extends vertically for a predetermined length from a pinch roller that slides in sliding contact with the pavement path road bed so as to be able to move up and down. A second laser receiver is provided that outputs the deviation from the beam receiving point, and a calculation device sequentially stores the output value of the first laser receiver for each signal of the distance detector, and also outputs the output value of the first laser receiver for each signal of the distance detector. The pavement thickness is determined from the output difference at the same point at 4f5 (where the laser beam reaches the measurement position of the preceding first laser receiver).

Embodiments The following will explain the present invention using the illustrated embodiments. It is placed upwards. A laser projector 2 is provided at a predetermined position near the work site, and this laser projector 2 projects a laser beam 3 substantially parallel to the roadbed along the moving direction VC of the finisher 1.

A distance detector 4 is located slightly in front of the finisher 1 in the direction of movement.
is installed, and this distance detector 4 is connected to the roadbed 5 before paving.
The finisher 1 is movable up and down and comes into sliding contact with the finisher 1 to measure the moving distance of the finisher 1. The distance detector 4 is composed of a rotary encoder or the like, and outputs a signal for each distance, which will be described in detail later.

The distance detector 4 also has a rod 7 extending vertically upward for a predetermined length and sliding vertically together with the distance detector 1.
is attached, and a first laser receiver 8 is attached to its upper end.

This first laser receiver 8 receives the laser beam 3 projected from the laser projector 2 described above, and connects this light receiving point with a reference point SO set at a predetermined height position of the first laser receiver 8. Outputs the vertical deviation X.

Further, a pinch roller 9 is installed behind the distance detector 4 by a distance nL in the direction of movement of the finisher 1, and slides on the paving return roadbed 6 so as to be able to move up and down. A rod 10 extending vertically upward to a predetermined height is attached to the pinch roller 9, similar to the rod 7 described above, and a second laser receiver 11 is attached to the upper end of the rod 10.

This second laser receiver 11 is provided at a position shifted from the first laser receiver 8 in the direction perpendicular to the traveling direction, and similarly to the laser receiver 8) receives the laser beam 3. , outputs the vertical deviation y between this light receiving point and the reference point So.

It is equipped with a calculation device (not shown) that processes each of these output signals, and when the distance detector 4 outputs a signal for each distance as the finisher 1 advances, the laser receiver 4 outputs a signal at each distance. 8 output values X are sequentially stored in memory. In addition, the computing unit includes first and second laser receivers 8 and 11.
From the distance 11nL between, the distance detector 4 outputs a signal n times from the specific position measured by the first laser receiver 8, and when the second laser receiver 11 reaches the position, the stored value of X and y The deviation from the value is output as the pavement thickness.

In the above configuration, the distance detector 4 will be described with reference to the flowchart in FIG. It emits a signal every fixed distance, and when it receives this signal (step a),
The arithmetic unit stores the output value X of the first laser receiver 8 in the memory area according to the value m of the address pointer at that time.
(step b+c+d) and at the same time advance the address pointer by one to m+1 in step e), read Xm+1 from the memory area in step h),
The difference T=y−Xm+1 from the output value y of the laser receiver 11 is calculated, and T is displayed on the display section as the pavement thickness (steps h and i).

j).

Also, the address pointer is a ring counter and n+1
When it exceeds, count again from 1 (steps f, g)
.

In this way, it is possible to display the difference between the value y measured by the second laser receiver 11 and the value measured nL thousand moves before the current position by the first laser receiver 8, where nL = first and second laser receivers. By setting the distance to 8 and 11, the second laser light receiving distance is 11.
The pavement thickness at the location can be measured and displayed.

Effects of the Invention The embodiment of the pavement thickness detection device according to the present invention has the above-described advantages, and can bring about the following effects.

Since the change in height before and after paving is compared using a laser beam as a reference, accurate measurement is possible without being affected by the levelness of the roadbed. In addition, the laser beam only determines the origin of the height measurement at each horizontal position.The relative height to the roadbed is irrelevant to the measurement unless it is outside the receiving range of the receiver, so the installation of the projector is difficult. It becomes easier. Furthermore, accurate measurements can be made even at points where the roadbed approaches a slope.

[Brief explanation of the drawing]

FIG. 1 is an overall schematic diagram showing an embodiment of the present invention. 1. Finisher, 2. Laser projector 3. Laser beam, 4. Distance detector 5. Pre-paving roadbed, 6. Pavement diameter. Roadbed 7: Rod, 8: First V-laser receiver 9: Pinch roller, 10: Rod 11: Second laser receiver.

Claims (1)

[Claims] (1) A laser projector is installed near the roadbed to be paved and projects a laser beam almost parallel to the roadbed along the position of the finisher moving above the roadbed; a distance detector that slides in vertically movable contact and outputs a signal every predetermined advance distance of the finisher; and a distance detector that is mounted on a shaft that extends vertically upward for a predetermined length from the distance detector to receive the laser beam. a first laser receiver that outputs the positional deviation between its own reference point and the laser beam receiving point, and a pinch roller that is attached to the rear side of the finisher in the direction of travel and that slides into vertically movable contact with the roadbed after paving. a second laser receiver that is mounted on a shaft extending vertically for a predetermined length, has the same reference point as the first laser receiver, and outputs a positional deviation between the laser beam receiving point and the reference point; , The output value of one laser receiver is sequentially stored for each signal output of the distance detector, and each time the second laser receiver reaches the measured position of the preceding first laser receiver, the corresponding stored value is stored. A pavement thickness detection device comprising: an arithmetic device that reads an output value of a first laser receiver and calculates a deviation between both values.