JPH03166405A - Control device of screed work angle for civil engineering machine - Google Patents

Abstract

PURPOSE:To always make the surface of a pavement even by providing detecting sensors for detecting a vertical movement in a screed and a machine body respectively having an expansion mechanism, and driving the expansion mechanisms with this detecting signal to control the work angle accurately. CONSTITUTION:A control device consists of a machine body 1, a screed 7, a leveling arm 9, a sub arm 11, a first and a second expansion mechanisms expansible in the vertical direction, a sensor 39 for detecting a vertical movement of the machine body 1, a sensor 45 for detecting a vertical movement of the screed 7, and a driving means. A vertical movement of the screed 7 is detected by the sensor 45 to expand and shrink the second expansion mechanism 19 with this signal, and the leveling arm 9 is moved vertically to obtain the accurate work angle of the screed 7. A vertical movement of the machine body 1 is detected by the first machine body detecting sensor 39 to expand and shrink the first and the second expansion mechanisms 17, 19 simultaneously. The work angle can be thereby controlled accurately to make the surface of a pavement even.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) This invention provides a control device that automatically controls the working angle of a screed in a civil engineering machine such as an asphalt finisher that evenly levels a paved surface. It is related to.

(Prior Art) In general, a paved surface is finished into a fairly uniform paved surface by a screed. To briefly explain this principle, as shown in Fig. 7, the screed 10 has a combined force of traction force P and weight W. F starts working. The screed 101 has a predetermined working angle α, and a combined reaction force R of a reaction force against the propulsive force of the screed 101 and a reaction force against the weight acts. When F and R are balanced, the screed 101 is kept at a constant height, making it possible to spread the paving material to a predetermined thickness.

If the working angle α is changed, the balance between F and R will be disrupted, and the screed 101 will move up and down to a position where they are balanced again, making it possible to change the pavement thickness.

The working angle α of the screed 101 is the leveling arm 103
The hydraulic cylinder 105 can be adjusted by moving the traction section up and down with a hydraulic cylinder 105, and the operation of the hydraulic cylinder 105 is controlled by a solenoid valve 109 which is switched based on a detection signal from a detection sensor 107.

(Problems to be Solved by the Invention) As described above, the leveling arm 103 that changes the working angle α of the screed 101 moves up and down based on the detection signal from the detection sensor 107. Detection sensor 10
7 is known, as shown in the figure, one type is placed near the screed 101, and the other type, not shown, is placed near the traction part.

In the former case, in which the detection sensor 107 is arranged near the screed 101, the vertical movement of the screed 101 can be accurately detected and corrected, so that a uniform paved surface can be obtained.
When the machine body 111 side moves up and down due to unevenness of the roadbed, etc., the height of the traction section changes, and the working angle α of the screed 101 also changes.

Furthermore, since the detection sensor 107 starts correction after the height of the screed 101 starts to change, follow-up control is always performed, and small waves are likely to occur, making it difficult to obtain a uniform paved surface.

On the other hand, in the latter case where the detection sensor is placed near the towing part, even if the machine body 111 moves up and down due to unevenness of the roadbed, the position of the towing part is immediately corrected, and the working angle α is kept constant. , from the screed 101 to the detection switch 107
Since the screeds are far apart, it is not possible to accurately respond to the vertical movement of the screed 101, causing problems such as small waves on the pavement, and each has its advantages and disadvantages.

In this case, as a means to eliminate the above-mentioned problem, for example, it may be possible to arrange the mounting position of the detection sensor 107 at a position intermediate between the former and the latter, but in reality, both of the drawbacks overlap, and the vertical movement of the screed 101 cannot be detected. There was a problem in that the sensitivity of the vertical movement detection of the aircraft was poor, making it difficult to expect good control.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a screed working angle control device for civil engineering machinery that eliminates the above-mentioned problems.

[Structure of the Invention] (Means for Solving the Problem) In order to achieve the above object, the present invention includes a leveling arm that changes the working angle of the screed by vertical movement, and one side of which rotates around the leveling arm. a sub-arm movably supported and the other connected to the fuselage; a first extendable and retractable arm that moves the sub-arm and the leveling arm up and down;
a second telescopic mechanism; a body detection sensor placed near the sub-arm to detect vertical movement of the body; a screed detection sensor placed near the screed to detect vertical movement of the screed; and a detection signal from the body detection sensor. a first driving means for simultaneously extending and contracting the first and second telescopic mechanisms so that when either the sup arm or the leveling arm is ascending, the other is descending based on the above, and a detection signal from the screed detection sensor; a second telescoping mechanism that extends and contracts the second telescoping mechanism so that the leveling arm moves up and down based on
and a driving means.

(Function) According to this screed working angle control device, for example,
When the screed detection sensor detects the vertical movement of the screed, the second driving means operates based on the detection signal, and the leveling arm moves up and down by the extension or contraction of the second telescoping mechanism to obtain an accurate working angle of the screed. It becomes like this.

Further, when the body detection sensor detects vertical movement of the body, the first driving means operates based on the detection signal, and the first and second expansion and contraction mechanisms simultaneously expand and contract. At this time, for example, when the sub-arm goes up, the leveling arm goes down correspondingly, so the upward movement of the leveling arm is canceled out, and the working angle of the screed is not affected.

(Embodiment) Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings of FIGS. 1 to 6.

In the figure, reference numeral 1 indicates a machine such as an asphalt 1 finisher that can be driven by a traveling device 3 such as a caterpillar. Although not shown, the machine body 1 includes a hopper for feeding the paving material, a conveyor device (not shown) such as a bar feeder that sends the paving material stacked in the hopper to the rear, and a spiral cross-feeding device 5 that spreads the moon to the left and right;
It has a screed 7 that evenly levels the pavement debris spread from side to side.

The screat 7 is formed long in the vehicle width direction and is supported by a leveling arm 9 that is long in the front and rear. The bottom surface of the screed 7 is the active surface that controls the vertical movement of the leveling arm 9 (
The working angle α, which changes according to the rust line in Figure 1, is confirmed.

In front of the leveling arm 9, one side of the sub-ar 11 is supported by a pivot 13 so as to be movable up and down. The other side of the sub-arm 11 is connected to the rotating arm 7t by a connecting member 17 to a traction hitch 15 that moves up and down along upper and lower guy rails 13 fixed to the body 1.

The sub-arm 11 and the leveling arm 9 can be moved up and down by a first telescopic mechanism 17 and a second telescopic mechanism 19.

That is, the first telescopic mechanism 17 and the second telescopic mechanism 19 are separated from the cylinder 21 and the piston rod 23 that reciprocates within the cylinder 21, and oil is sent into the first chamber 21a of each cylinder 21, so that the piston rod 23 is Nakanaga,
It is a double-acting type that shrinks by feeding the ura into the second chamber 2lb.

The cylinder 21 of the first telescopic mechanism 17 is pivotally supported on the body 1, and the piston rod 23 is pivotally supported on the tow hitch 15. As a result, the sub-arm 11 can be lowered by extension of the piston rod 23, and raised by contraction.

Further, the cylinder 21 of the second telescopic mechanism 19 is pivotally supported by the sub-arm 1l, and the piston rod 23 is pivotally supported by the leveling arm 9. As a result, the piston rod 2
3, the leveling arm 9 can be raised by extension, and can be lowered by contraction.

The installation position of the second telescoping mechanism 19 is determined by the distance Ml corresponding to the distance ゛V, assuming that the distance from the connection point where the piston rod 23 of the first telescoping groove] 7 is attached to the pivot 13 of the sub-arm 11 is 2 lengths. It is located in

That is, the operating positions of the first telescoping mechanism 17 and the second telescoping mechanism 19 are set at a ratio of approximately 2:1 with respect to the pivot support [3] which serves as a pivot point for the sub-arm 11.

As a result, for example, the piston rod 23 of the first telescoping mechanism 17 is moved against the second telescoping mechanism 1 with respect to the
By controlling the stroke rate at which the piston rod 23 of 9 extends to 2=1, for example, the leveling arm 9 can move upward in response to the amount of descent of the sub-arm 11, and the movement of the leveling arm 9 It becomes possible to easily determine the amount of operation that cancels out.

FIG. 2 shows the first ura LE circuit 25 that controls the first telescoping machine slide 17 and the second ura pressure circuit 2 that controls the zigzag expansion mechanism 19.
7 are shown respectively.

The first pressure circuit 25 is connected to each boat p on the intake side and the extraction side.
+ ・P2 ・P3 ・P4 are connected and communicated with a switching control valve 29 having a Subur valve S 2 ・S2,
In the neutral state, the pressure of the hydraulic pump 31 returns to the tank 33. Further, as shown in FIG. 3, one Subur valve SI connects and communicates with the boats P3 and P4 from the neutral position, so that the hydraulic pressure from the pressure bomb 31 is transferred to the first and second telescopic mechanisms 17 through the diversion valve 37. .19 each cylinder 2
1 into the first chamber 21a. Also, the fourth
As shown in the figure, the other spool valve S2 is the boat P]・P4
The pressure from the pressure bomb 31 is connected and communicated with the first pressure bomb 31 through the diverter valve 35. It is fed into the second chamber 2 lb of each cylinder 21 of the second telescoping mechanism 17, 19, respectively. In addition to the function of sending hydraulic pressure to each cylinder 21, each of the flow dividing valves 35 and 37 has the function of distributing the working stroke of the piston rod 23 of the first telescopic mechanism 17 to the working stroke of the piston rod 23 of the second telescopic mechanism 17. 21.2 in each cylinder so that the ratio is approximately 2:2.
1 to {j (has the function of limiting the amount of supply).

Further, each of the Subur valves S and -S2 of the switching control valve 29 is switched and controlled based on a detection signal from a body detection sensor 39 disposed near the sub-arm 11.

The sensor section 39a of the aircraft body detection sensor 39 is capable of running along a reference plane 41 provided outside the paved road surface, detects the vertical movement of the aircraft body 1 during running, and outputs a signal for raising or lowering. Note that the base surface 41 may be formed by using the side of the road, or by newly laying a sensor rope or the like.

The second hydraulic circuit 27 is connected to each boat P on the intake side and the extraction side.
1. A switching control valve 43 having Suburd valves S1 and S2 connected and communicating with P2, P3, and P4 is provided, and the pressure of the hydraulic pump 31 is returned to the tank 33 in the neutral state. Further, as shown in FIG. 5, one Subur valve Sl is connected and communicated with bows P3 and P4 from the neutral position, so that the hydraulic pressure from the hydraulic pump 31 is transferred to the first chamber 21a of the cylinder 21 of the second telescopic mechanism 19. sent.

Further, as shown in FIG. 6, the other Subur valve S2 is connected and communicated with the boats P3 and P4, so that the hydraulic pressure from the hydraulic pump 31 is sent to the second chamber 2lb of the cylinder 21 of the second telescopic mechanism 19, respectively.

The switching control valve 43 is controlled to switch based on a detection signal from a screed detection sensor 45 disposed near the screed 7.

The screed detection sensor 45 is located behind the body detection sensor 39, and the sensor section 45a can travel along the reference 41, detects the vertical movement of the screed 7, and outputs a signal for raising or lowering. Note that when the body detection sensor 39 and the screed detection sensor 45 operate at the same time, priority is given to the signal from the sensor that detected first.

Note that in the hydraulic circuit, 47 indicates a pilot check valve. This check valve 47 is connected to the cylinder 21 when pilot pressure is applied through the circuit shown by the dotted line.
The pressure inside the first chamber 21a or the second chamber 2lb is transferred to the tank 33.
It has a function to escape to.

According to the screed working angle control device configured in this way, for example, when the screed detection sensor 45 detects the vertical movement of the screed 7, a raising or lowering signal is output, and based on the signal, the second hydraulic circuit 27 works, second
One telescopic mechanism operates telescopically. As a result, the leveling arm 9 moves up and down, and an accurate working angle α of the screed 9 can be obtained.

Further, when the body detection sensor 39 detects the vertical movement of the body 1, a signal for raising or lowering is output, and the first hydraulic circuit 25 operates based on the signal. Second telescoping mechanism 17.
19 operates to expand and contract at the same time.

As a result, for example, when the leveling arm 9 rises in accordance with the amount of descent of the sub-arm 11, the sub-arm 11
is a movement using the pivot shaft 13 as a fulcrum, and the leveling arm 9 is not affected and the working angle α does not change.

In addition, in this example, hydraulic means was adopted, but
It is also possible to control electrically using a servo motor or the like.

[Effects of the Invention] As explained above, according to the screed working angle control device of the present invention, the vertical movement of the machine body and the vertical movement of the screed are detected by the machine body detection sensor and the screed detection sensor, and the working angle is accurately controlled. As a result, a uniform paved surface can be obtained.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the screed working angle control device of the present invention, FIG. 2 is a first and second pressure circuit diagram, and FIGS. 3, 4, and 5rI! J, FIG. 6 is an explanatory diagram of the operation, and FIG. 7 is an explanatory diagram similar to FIG. 1 showing a conventional example. 1... Aircraft body 7... Screed 9... Leveling arm 11... Sub arm 17.19... tB1.152 intermediate machine purchase 25... First pressure circuit (driving means) 27. ...Second hydraulic circuit (
Driving means) 39... Aircraft detection sensor 45... Screed detection sensor procedure amendment (voluntary) December 22, 1999 To the Commissioner of the Special RR Agency 1. Case description 1999 Patent Application No. 303086 2. Name of the invention: Control device for screed working angle of civil engineering machinery Representative: Hirotoranomon Shimizu, 5th floor, Building 1 Name:

Claims (1)

[Claims] a leveling arm that changes the working angle of the screed by vertical movement; a sub-arm with one side rotatably supported by the leveling arm and the other connected to the fuselage; and an extendable first arm that moves the sub-arm and the leveling arm up and down. , a second telescopic mechanism, a body detection sensor disposed near the sub-arm to detect vertical movement of the machine body, a screed detection sensor disposed near the screed to detect vertical movement of the screed, and detection from the body detection sensor. a first driving means for simultaneously extending and contracting the first and second telescopic mechanisms so that when either the sub-arm or the leveling arm is ascending based on a signal, the other is descending; and a detection signal from the screed detection sensor; and a second drive means for extending and contracting the second telescoping mechanism so that the leveling arm moves up and down based on the leveling arm.