JP2008285962A - Leveling height control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a leveling height control device, capable of improving accuracy at low cost in addition to improvement in work efficiency. <P>SOLUTION: The leveling height control device is adapted to adjust the leveling height of a material to be leveled by a leveling device 1 provided on a rear part of a traveling vehicle by controlling an attitude adjustment device (a leveling cylinder and an arm) which adjusts the attitude of the leveling device 1 (screed). The control device therefor comprises a reference cable 2 laid along a moving direction of the leveling device 1, a feeder 4 for feeding electricity to the reference cable 2, a detector 3(3b) which detects a magnetic field generated by a current carried in the reference cable 2, and a controller 3(3a) which controls the attitude adjustment device so that the vertical position of the detector 3 to the reference cable 2 is constant. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a technique for laying surface layer materials such as roads and parking lots, and more particularly to a material leveling device.

  For example, a self-propelled machine called asphalt finisher is known as a machine for spreading and leveling paving materials on paved roads. This machine is provided with a bar feeder, a screw spreader, and the like for spreading a material discharged from the hopper while moving forward on a traveling vehicle having a hopper for storing the leveling material. A spreader called a screed for spreading and spreading the material spread by the spreader for spreading the covering material is further provided at the rear of the traveling vehicle, and it is performed until compaction. Yes.

  In a machine for leveling such materials, control the attitude adjustment device that adjusts the attitude of the leveling device to level the leveling material with as even leveling as possible A spread height control device as described in Patent Document 1 is provided. This Patent Document 1 discloses a mechanical spread height control device (prior art column) that imitates a water yarn (sensor rope) stretched in the moving direction of the spreader as a height reference line with an arm. In addition, a sensor-type spreader height control device (Example column) that detects the water yarn with an ultrasonic unit is described.

In the case of Patent Document 1, the posture adjusting device (leveling arm and leveling cylinder) adjusts the inclination angle as the posture of the leveling device in accordance with the leveling height control device. When the inclination of the spreader changes, the amount of spreader material that is swallowed under the spreader changes, so that the spreader height is adjusted.
JP-A-8-13412

  In the conventional spread height control apparatus as described above, a water yarn is used as a reference line for height. However, it takes time and effort to improve the tension, and improvement is desired. In other words, for example, when paving on the floor slab of a bridge, the water string is stretched on the handrail at the side edge, but the height of this handrail is not constant, so surveying, It is necessary to arrange the tops (cubic resin pieces laid down for height adjustment, etc.) below so that the water string is stretched to the reference height. These frames must be arranged at intervals of about 5 m, which is a troublesome task.

  Further, in Patent Document 1, in order to solve the problem of the accuracy of the spreader height device that imitates the water yarn with a mechanical arm, the spreader height control that detects the water yarn in a non-contact manner using ultrasonic waves. A device has been proposed. However, since a large number of ultrasonic sensor units are used side by side, high costs are inevitable.

  The present invention is based on such a technical background, and proposes a spread height control device that can improve workability and improve accuracy at a lower cost than an ultrasonic type.

  The spread height control device according to the present invention includes a spread leveling device provided at the rear of a traveling vehicle provided with a device for spreading spread material such as a hopper, a bar feeder, and a screw spreader. In order to adjust the leveling height of the spreading material, a posture adjusting device for adjusting the posture of the leveling device is controlled. In general, the posture adjustment device is controlled by using a wire as a height reference line and detecting a magnetic field generated by energizing the wire. That is, a reference wire that extends along the direction in which the leveling device is moved, a power feeder that feeds the reference wire, and a device that is attached to the leveling device and moves close to the reference wire, It is characterized by including a detector that detects a magnetic field generated by a current flowing through the electric wire, and a controller that controls the attitude adjustment device according to the detection result of the detector.

  The spread height control apparatus according to the present invention uses a wire as a reference line for height and detects a magnetic field generated in the wire. For example, in the case of installing the cable in the above-mentioned railing, the wire extension work is marked on the side surface of the railing by using an adhesive, adhesive tape, etc. It is a simple task such as making an electric wire run. In other words, compared to the case of a water thread that has to be tensed while adjusting the height by placing a piece underneath, it is much easier.

  The detector for detecting the magnetic field of the electric wire may be, for example, one using a coil that generates an induced current in accordance with the magnetic field, and can be configured with low-cost components compared to the ultrasonic sensor. That is, it is possible to obtain a non-contact type device with higher accuracy than the mechanical type that imitates the water yarn with the above-described arm at a lower cost.

  A preferred embodiment of the present invention is shown in FIGS.

  The spread height control device of this example is applied to an asphalt finisher as described in FIG. The asphalt finisher includes a hopper that accumulates the covering material at the front of the traveling vehicle, and the covering material discharged from the hopper while moving forward is provided with a bar feeder provided at the lower portion of the traveling vehicle. And spread it with a screw spreader. A screed is provided behind the traveling vehicle as a leveling device that is adjusted in posture by a posture adjusting device including a leveling cylinder (hydraulic cylinder) and a leveling arm. Spreading material is spread and leveled.

  This leveling device can change the inclination angle with respect to the construction surface by rotating the leveling arm by the expansion and contraction of the leveling cylinder. Thus, by adjusting the inclination angle, which is the posture of the leveling device in this example, with the posture adjusting device, the amount of the leveling material swallowed under the leveling device changes. The leveling height by the device can be adjusted.

  FIG. 1 and FIG. 2 show a case where asphalt pavement is performed on a bridge slab by using such an asphalt finisher. As shown in FIG. 1, the spread height control device according to the present embodiment is configured to include a reference wire 2 and a detector and controller 3 attached to the side end of the spread device 1. ing. In FIG. 1 and FIG. 2, only the left end portion of the spreader 1 is shown, and the other portions are omitted.

  The reference wire 2 is provided along the direction in which the leveling device 1 is moved (indicated by the arrow X in the figure), that is, in the case shown, along the side edge of the floor slab that is the construction surface. A side surface of A is attached and extended by an adhesive tape 2a. The reference electric wire 2 is used as a height reference by measuring the side surface of the rail A and extending it so as to trace the height reference line. The reference electric wire 2 in this embodiment is a two-core feeder wire in which a single conductor 2b is folded (see FIG. 3) and resin-coated in parallel to each other. Both ends of the reference electric wire 2 are connected to a power feeder 4 installed on the rail A with hooks B. The power feeder 4 is installed outside the handrail A so as not to obstruct the construction.

  In the present embodiment, the power feeder 4 that feeds the reference wire 2 supplies an alternating current having a frequency of 2 kHz. Therefore, in the reference electric wire 2, a magnetic field whose magnitude and direction are changed by the alternating current is generated around the conductive wires 2b that are vertically parallel. The detection and control unit 3 detects the magnetic field and executes control.

  As shown in FIG. 2, the detector and controller 3 includes a controller 3a and a detector 3b that protrudes from the side surface of the controller 3a. In the case of this embodiment, a bowl-shaped column 1b extending upward from the end plate 1a at the side end of the spreader 1 is provided, and the detection and controller 3 is suspended downward from the column 1b. It is being fixed to the lower end of the extended telescopic support tool 1c. At the upper end of the telescopic support tool 1c, there is a handle 1d for expanding and contracting the telescopic support tool 1c, and the vertical position of the detection and controller 3 can be finely adjusted by rotating the handle 1d. That is, fine adjustment such as initial positioning with respect to the reference electric wire 2 can be performed by the handle 1d.

  In the present embodiment, the detector 3b integrated with the controller 3a is attached to the leveling device 1 as described above, so that it is close to the reference electric wire 2 extending on the side surface of the rail A. Move. And the magnetic field produced by the electric current which flows through the reference | standard electric wire 2 is detected, moving with the leveling apparatus 1. FIG. The mechanism of the magnetic field detection is schematically shown in FIG.

  The detector 3b includes two upper and lower coils 3c and 3d corresponding to the two upper and lower conductive wires 2b of the reference electric wire 2 that are parallel to each other. Since the two conducting wires 2b are formed by folding one conducting wire, when alternating current is passed, magnetic fields opposite to each other are generated. The two coils 3c and 3d are reversely wound with each other, and each of them generates an induced current mainly according to a change in the magnetic field generated in one of the two conductive wires 2b which are vertically parallel. There may be a device that detects a magnetic field by using a Hall element or the like instead of a coil, but using the electromagnetic induction of the coil is more accurate and less expensive.

  The controller 3a compares the induced currents generated by the two coils 3c and 3d, and determines whether the magnitude (amplitude) of the two is balanced. That is, since the two conducting wires 2b are obtained by folding one conducting wire, the magnetic fields generated in both the wires should have almost the same strength. Therefore, if the vertical center between the coils 3c and 3d in the detector 3b and the vertical center between the two conductors 2b substantially coincide, the magnitudes of the induced currents through the coils 3c and 3d should be balanced. .

  On the other hand, when the spread height changes due to the unevenness of the floor slab surface, a deviation occurs between the vertical center between the coils 3c and 3d and the vertical center between the two conductors 2b. Then, a change occurs in the magnitude of the induced current of both the coils 3c and 3d, and they are not balanced. For example, when the spread height is increased and the detector 3b is shifted upward, the upper coil 3c is separated from the reference electric wire 2, so that the induced current is weakened. On the other hand, the lower coil 3d is Since an induced current due to a magnetic field generated in a different upper conductive wire 2b is generated, the induced current caused by the coil 3d has a different waveform.

  The controller 3a compares the magnitudes of the induced currents generated in the coils 3c and 3d according to the change of the magnetic field generated in the reference wire 2 based on the detection result of the both magnetic fields by the detector 3b. The vertical position of the detector 3b with respect to the reference wire 2 is determined. Then, the posture adjusting device is controlled so that the vertical position of the reference electric wire 2 is constant, that is, the vertical center of the reference electric wire 2 and the vertical center of the detector 3b coincide.

  Specifically, in response to a command (control signal) from the controller 3a, the leveling cylinder constituting the posture adjusting device expands and contracts, and the leveling arm rotates by the expansion and contraction of the leveling cylinder. When the leveling arm rotates, the inclination angle of the leveling device 1 changes and the amount of the leveling material squeezed under the leveling device 1 changes, so that the leveling height is adjusted. Note that illustration of signal lines, power cables, and the like for sending commands from the controller 3a is omitted.

  In this way, the spreader height can be controlled to be as constant as possible by controlling the detector 3b to trace the reference wire 2 at a certain position.

  In addition to controlling the attitude adjustment device so that the detector traces the reference wire at a fixed position in this way, the construction surface after leveling, for example, is based on the strength of the magnetic field by the reference wire. It is also possible to control so that the detector is intentionally shifted up and down so that it is waved intentionally and finished.

The principal part perspective view which showed embodiment of the leveling height control apparatus which concerns on this invention. The figure which looked at the spread height control apparatus of FIG. 1 from back. The circuit diagram which showed roughly the mechanism of the spread level control apparatus concerning the present invention.

Explanation of symbols

1 Leveling device 2 Reference wire 2b Conductor (core wire)
3 Detector and Controller 3a Controller 3b Detector 3c, 3d Coil 4 Feeder

Claims (4)

A posture of the leveling device for adjusting the leveling height of the leveling material by a leveling device provided at the rear of the traveling vehicle provided with a leveling material spreading device. A leveling height control device for controlling a posture adjustment device for adjusting
A reference wire extending along the direction of moving the spreader; and
A power feeder that feeds the reference wire;
A detector that is attached to the leveling device and moves in proximity to the reference wire and detects a magnetic field generated by a current flowing through the reference wire;
A controller for controlling the posture adjusting device according to a detection result of the detector;
A leveling height control device comprising:   2. The spreader according to claim 1, wherein the controller controls the posture adjusting device so that a vertical position of the detector with respect to the reference electric wire is constant according to a detection result of the detector. Height control device. The reference electric wire is a two-core feeder wire formed by folding one conductive wire,
The detector detects each magnetic field generated in the two core wires of the reference wire,
3. The spread height according to claim 1, wherein the controller determines a vertical position of the detector with respect to the reference wire based on a detection result of both magnetic fields by the detector. Control device. The power feeder supplies an alternating current to the reference wire,
The detector includes two coils corresponding to the two core wires of the reference electric wire,
4. The bed according to claim 3, wherein the controller determines the vertical position of the detector with respect to the reference wire by comparing induced currents generated in the coils according to a magnetic field generated in the reference wire. Leveling height control device.

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