JPH0712403Y2 - Spreading and leveling machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a laying machine such as an asphalt finisher.

[Prior Art] An asphalt finisher, which is one of the spreading machines of this kind, rolls out an asphalt mixture (hereinafter referred to as a mixture) to the rear of the vehicle body while running, Is squeezed with a screed device and spread. Then, normally, the screed device is adapted to compact the composite material by its own weight.

However, in the above asphalt finisher,
Since the screed device is used for compacting the mixture, the amount of sinking of the screed device with respect to the mixture changes due to the difference in hardness of the mixture, and the thickness of the mixture after paving varies. There are drawbacks.

Therefore, it has been proposed to provide between the traveling vehicle body and the screed device, elastic holding means for elastically levitating and holding the screed device, the elastic holding means being a coil spring or a hydraulic cylinder with an accumulator. 60-
23503).

[Problems to be Solved by the Invention] However, when the structure for reducing the weight of the screed device by the elastic holding means composed of a coil spring or a hydraulic cylinder with an accumulator is adopted, the elastic holding means is adjusted depending on the vertical position (height) of the screed device. However, there is a problem that the pavement thickness cannot be controlled accurately because the holding force of the pavement changes (the holding force decreases as the height of the screed device increases).

Although the above-mentioned publication discloses that the coil spring is provided with means for adjusting the elastic force thereof, even if the coil spring is provided with the elastic force adjusting means, the holding force can be quickly responded to a change in height of the screed device. It cannot be constant.

According to the present invention, the weight of the screed device does not change depending on the height, and even if the hardness of the spread material such as a composite material changes, the spread material is spread evenly with a uniform thickness. It is an object of the present invention to provide a spreading and leveling machine that can be used.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention is provided on a traveling vehicle body so as to be movable in the vertical direction, and uses a weight of itself to provide a leveling material such as an asphalt mixture. In a leveling machine equipped with a screed device for compaction, a pair of left and right hydraulic cylinders, which act to lift the screed device with a force smaller than the weight of the screed device, are provided between the traveling vehicle body and the screed device. A pressure reducing valve capable of adjusting the set pressure for individually reducing the pressure of the hydraulic oil is provided in each pipeline for supplying the hydraulic oil of the source to each of the hydraulic cylinders.

[Operation] The pair of left and right hydraulic cylinders operate so as to lift the screed device with a force smaller than the weight of the screed device in accordance with the set pressure set in each pressure reducing valve. The lifting force (holding force) of the screed device by the hydraulic cylinder does not change depending on the vertical position of the screed device. Therefore, by adjusting the set pressure of each pressure reducing valve according to the hardness of the spread material, the sinking amount of the screed device can be kept constant and the thickness of the spread material can be accurately adjusted to a predetermined thickness. Can be

Also, when the screed device leans in the width direction of the road due to the crossing gradient of the road and the weight of the screed device is different between the left side and the right side, the left and right hydraulic cylinders are paired according to the weight difference. Adjust the set pressure of the pressure reducing valve.

[Embodiment] An embodiment in which the present invention is applied to an asphalt finisher will be described below with reference to FIGS. 1 to 3.

As shown in FIGS. 1 and 2, the asphalt finisher rotates a rear wheel 1 and a front wheel 2 to drive a vehicle body (running vehicle body) 3 while driving a mixture (filler) introduced into a hopper 4 into a conveyor (bar feeder). ) 5 to the rear spreading screw 6, where it is evenly spread to the left and right (in the direction perpendicular to the plane of the paper in FIG. 1) and spread on the road surface by a screed device 8 suspended behind the support arm 7. It is constructed so that it can be laid evenly on a flat surface. The front wheel 2 is configured to function as a driving wheel that also serves as a steering wheel, and is driven only by the rear wheel 1 without driving the front wheel 2 as needed.

One support arm 7 is provided along each of the left and right side surfaces 3a of the vehicle body 3, and its tip end portion 7a is rotatably connected to the front side surface 3a of the rear wheel 1 by a pin 9.
The support arm 7 includes a front end portion 7a and a front side bent portion 7b bent upward so as to avoid the rear wheel 1 from the front end portion 7a.
And an intermediate portion 7c extending rearward from the front bent portion 7b on the upper side of the rear wheel 1 and further projecting rearward from the rear end surface 3b of the vehicle body 3,
The intermediate portion 7c is bent obliquely rearward and downward, and is integrally formed by a belt-shaped member by the rear bent portion 7d for mounting the screed device 8.

The screed device 8 is configured such that its width in the left-right direction can be extended in the left and right directions, and its bottom surface 8a is formed in a flat shape, and the pin 9 of the support arm 7 is used as a fulcrum. By rotating downward, the composite material is flatly compacted and solidified on the bottom surface 8a and spread.

Brackets 10 are provided on the rear end surface 3b of the vehicle body 3 at the upper portions of the left and right ends thereof. The brackets 10 and the rear bent portions 7d of the left and right support arms 7 are provided with hydraulic cylinders (holding members). (Member) 11 is connected. Each hydraulic cylinder 11
The end of the cylinder tube 11a on the head side is rotatably connected to each bracket 10 by a pin 12, and the tip of the piston rod 11b is rotatably connected by a pin 13 to a rear bent portion 7d of each support arm 7. It is connected. Each hydraulic cylinder 11 thus mounted is controlled by the hydraulic circuit shown in FIG.

Explaining this hydraulic circuit, one hydraulic cylinder 11 is
The rod side of the cylinder tube 11a is connected to the downstream side of the first pressure reducing valve 16 via the pipelines 14 and 15, and the other hydraulic cylinder 11 has the rod side of the cylinder tube 11a via the pipelines 17 and 18. It is connected to the second pressure reducing valve 19. Further, each hydraulic cylinder 11 has its cylinder tube 11a.
The head side of is connected to a tank 21 via a tank pipe 20. Further, the pipe line 15 and the pipe line 18 are connected to each other, and the connected portion is connected to the downstream side of the first manual stop valve 22. The upstream side of the first stop valve 22 is connected to a hydraulic pressure source 25 via a forwarding solenoid valve 24 for raising the screed device 8 when forwarding the asphalt finisher. In the forward solenoid valve 24, the P port and the A port are in a non-communication state when neutral, and the P port and the A port are in a communication state when the solenoid 24a is energized.
25, and the A port is connected to the first stop valve 22. Further, the upstream sides of the first pressure reducing valve 16 and the second pressure reducing valve 19 are connected to the downstream side of a manual second stop valve 27 via a pipeline 26, and the second stop valve is connected. The upstream side of 27 is connected to the hydraulic power source 25.

In the asphalt finisher configured as described above, when the solenoid 24a is energized with the first stop valve 22 open and the second stop valve 27 closed, the pressure oil supplied from the hydraulic pressure source 25 is circulated. It is supplied to the rod side of the cylinder tube 11a of each hydraulic cylinder 11 from the pipe line 15 or the pipe line 18 through the A port and P port of the solenoid valve 24 for use and the first stop valve 22. Then, at the pressure set by the hydraulic pressure source 25, the hydraulic cylinder 11
Rod 11b contracts, and screed device 8 rises. Then, the screed device 8 is held in a lifted state by a mechanical stopper or the like, so that the screed device 8 can be forwarded. However, at the time of forwarding, the first stop valve 22 is closed and the forwarding solenoid valve 24 is returned to the neutral state.

In addition, when laying the mixture, the first stop valve 22
The second stop valve 27 is opened in the closed state. Then, the pressure oil supplied from the hydraulic pressure source 25 is supplied to the rod side of the cylinder tube 11a of the one hydraulic cylinder 11 via the first pressure reducing valve 16, and the other hydraulic pressure is supplied via the second pressure reducing valve. Cylinder tube 11 of cylinder 11
Supplied to the rod side of a. Therefore, one hydraulic cylinder 11 acts so as to lift the screed device 8 with a force (holding force) commensurate with the set pressure of the first pressure reducing valve 16, and the other hydraulic cylinder 11 causes the second pressure reducing valve 19 to move. The screed device 8 is lifted with a force commensurate with the set pressure. Therefore, the first pressure reducing valve 16 and the second pressure reducing valve 19
By adjusting the set pressure of, the surface pressure of the bottom surface 8a of the screed device 8 with respect to the composite material that is unwound from the spreading screw 6 is adjusted. Therefore, when the mixture is soft and the sink amount of the screed device 8 is large, the first
By increasing the set pressure of the pressure reducing valve 16 and the second pressure reducing valve 19 to reduce the surface pressure of the bottom surface 8a of the screed device 8 against the mixture, thereby suppressing the sinking amount of the screed device 8, Adjust to the same thickness as when laying out a mixture of normal hardness. Further, when the mixture material is hard and the sinking amount of the screed device 8 is small, the set pressures of the first pressure reducing valve 16 and the second pressure reducing valve 19 are lowered to lower the surface of the bottom surface 8a of the screed device 8 with respect to the mixture material. By increasing the pressure, the amount of sinking of the screed device 8 is increased, and the thickness is adjusted to be the same as in the case of laying and spreading a mixture material having a normal hardness. Further, when paving with a road having a cross slope with a high central portion, the surface pressure of the screed device 8 on the road shoulder side is usually higher due to the influence of the cross slope, but The holding force of the hydraulic cylinder 11 is made larger than the holding force of the other hydraulic cylinder 11, so that the screed device 8 for the composite material
The surface pressure of the bottom surface 8a of the is uniform. Then,
Even on a road with a cross slope, the thickness of the mix is almost uniform along the slope of the road. Furthermore, when the screed device 8 is biased to the left or right and stretched, the center of gravity of the screed device 8 moves to the stretched side.
Naturally, the surface pressure of the bottom surface 8a on the extended side increases. Therefore, in this case, the holding force of the hydraulic cylinder 11 on the extended side of the screed device 8 is relatively increased, and the surface pressure on the bottom surface 8a of the screed device 8 with respect to the mixed material is made substantially uniform.

In the asphalt finisher configured as described above, by adjusting the set pressure of the first pressure reducing valve 16 and the second pressure reducing valve 19, the surface pressure of the bottom surface 8a of the screed device 8 with respect to the unwound mixture is adjusted. Therefore, the amount of sinking of the screed device 8 with respect to the composite material can be adjusted. Therefore, even when the hardness of the mixture changes due to a difference in temperature, for example, the first pressure reducing valve
By adjusting the set pressures of 16 and the second pressure reducing valve 19, it is possible to spread the mixture material to a substantially uniform thickness.
Further, when paving a road having a crossing gradient, the surface pressure of the bottom surface 8a of the screed device 8 with respect to the mixture is adjusted to the left or right by adjusting the set pressures of the first pressure reducing valve 16 and the second pressure reducing valve 19. Since it can be made substantially uniform in the direction, the composite material can be spread evenly along the slope of the road to a substantially uniform thickness. Further, when the left and right widths of the screed device 8 are biased to one side and stretched, the surface pressure of the bottom surface 8a of the screed device 8 on the stretched side increases, but the first side of the stretched hydraulic cylinder 11 Pressure reducing valve 16 or second pressure reducing valve 19
By increasing the set pressure of 1, the surface pressure of the bottom surface 8a can be made substantially uniform in the left-right direction, and the composite material can be spread evenly in the left-right direction.

In the above embodiment, the manual stop valve
Although 22 and 27 are used, it goes without saying that the stop valves 22 and 27 may be electromagnetic switching valves that are opened and closed by an electric signal. Further, in the case of the electromagnetic switching valve, it can be automatically opened / closed by an electric signal, so that it is possible to save the operator the trouble of opening / closing the stop valve one by one.

Further, each hydraulic cylinder 11 is also used for lifting the screed device 8 at the time of forwarding and also on the bottom surface 8a of the screed device 8.
Although it is constructed so that it can also be used for adjusting the surface pressure, a surface pressure adjusting hydraulic cylinder 28 may be provided separately from the hydraulic cylinder 11 as shown in FIG.

[Effects of the Invention] As described above, the laying machine according to the present invention is provided on the traveling vehicle body so as to be vertically movable, and tightens the laying material such as asphalt mixture with its own weight. In a leveling machine equipped with a screed device for hardening, a pair of left and right hydraulic cylinders that act to lift the screed device with a force smaller than the weight of the screed device are provided between the traveling vehicle body and the screed device. The following effects can be obtained because the pressure reducing valve that can adjust the set pressure to individually reduce the pressure of the hydraulic oil is provided in each pipeline that supplies the hydraulic oil of the source to each of the hydraulic cylinders. is there.

Even if the hardness of the spread material changes due to temperature changes, by adjusting the set pressure of each pressure reducing valve according to the hardness of the spread material, the sinking amount of the screed device can be kept constant. Therefore, the thickness of the spread material can be accurately adjusted to a predetermined thickness.

Since the pressure of the hydraulic oil that operates the hydraulic cylinder to generate the holding force is determined by the set pressure of the pressure reducing valve and is not related to the vertical position of the screed device, it is possible to evenly spread and spread the leveling material.

Since a pair of left and right hydraulic cylinders, each equipped with a pressure reducing valve, are provided in the pipeline, even if there is a difference in weight between the left side and the right side of the screed device due to a road crossing gradient or expansion / contraction of the screed device, etc. By properly responding to this, the laying work can be smoothly performed.

[Brief description of drawings]

1 is a side view of an asphalt finisher shown as an embodiment of the present invention, FIG. 2 is a plan view of the asphalt finisher, FIG. 3 is a hydraulic circuit diagram of the asphalt finisher, and FIG. 4 is a diagram of the asphalt finisher. It is a side view which shows another example. 3 ... Main body (traveling vehicle), 8 ... Screed device, 11 ... Hydraulic cylinder, 14, 15 ... Pipe line, 16 ... Pressure reducing valve, 17, 18 ... Pipe line, 19
… Pressure reducing valve, 25… Hydraulic pressure source, 26… Pipe line, 28… Hydraulic cylinder.

Claims (1)

[Scope of utility model registration request] 1. A laying machine provided with a traveling vehicle body (3) so as to be vertically movable and provided with a screed device (8) for compacting a laying material such as asphalt mixture by its own weight. A pair of left and right hydraulic cylinders (11, 11) acting to lift the screed device (8) between the traveling vehicle body (3) and the screed device (8) with a force smaller than the weight of the screed device (8). 11) is provided,
The hydraulic oil from the hydraulic source (25) is transferred to the hydraulic cylinders (11, 11)
To each pipeline (26,15,14,26,18,17) that supplies
A leveling machine which is provided with a pressure reducing valve (16, 19) capable of adjusting the set pressure for individually reducing the pressure of hydraulic oil.