JPH0250259B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a bucket belt correction device for a loading shovel.

As shown in Fig. 1, a construction machine such as a loading shovel has an arm 3 rotatably disposed at the tip of a boom 2 that is disposed on the vehicle body so that it can be raised and lowered. A bucket 4 is rotatably attached to the. An arm cylinder 5 is disposed between the boom 2 and the arm 3. Further, the bottom 6a of the bucket cylinder 6 is attached to the bucket 4, and the rod tip 6a is attached to the bucket 4.
b is attached to the boom 2 and arm 3 via a link mechanism 7 as shown in the figure. When the arm cylinder 5 is extended, the arm 3 is pushed forward (in the direction of arrow A), and when it is shortened, it is pushed backward (in the direction of arrow B).
direction). Also, when the bucket cylinder 6 is extended, the bucket 4 moves upward (in the direction of arrow C).
When it rotates, it becomes a bucket tilt, and when it is shortened, it rotates downward (in the direction of arrow D) and becomes a bucket dump. In the loading shovel having such a configuration, since the bucket cylinder 6 and the arm 3 form a parallelogram link mechanically, the arm 3
When operated to the retracting side, the bucket angle changes, and the bucket upper part 4b moves to the stopper 8 fixed to the arm 3.
may occur. In such a case, the hydraulic circuit may be relieved or the engine may stall.

Conventionally, the operator predicted that a collision between the bucket 4 and the arm 3 as described above would occur during work, and
In order to prevent the bucket cart 4 from colliding with the arm 3, the bucket cart 4 is operated in advance to the dumping side (in the direction of arrow D), or the arm 3 is retracted and the dump truck is operated simultaneously. However, such an operation requires great skill and increases operator fatigue, and if the operator is inexperienced, the bucket 4 and the arm
It is easy to cause a collision with the engine, and this has the disadvantage of causing a relief phenomenon, engine stalling, etc. each time, resulting in a reduction in cycle time.

The present invention was made for the purpose of eliminating the above-mentioned conventional drawbacks.The present invention detects the rotation angle of the bucket cart with respect to the arm, and when the bucket cart approaches the stopper when the arm is retracted, the bucket cart is automatically corrected to the dump side. To provide a bucket belt correction device for a loading shovel which prevents collision of the bucket belt with an arm.

The present invention will be described in detail below based on an embodiment of the accompanying drawings.

FIG. 2 is an explanatory diagram of the rotation angles of the arm 3 and bucket belt 4 of the working machine 1 shown in FIG.
The angle γ represents the rotation angle of the bucket 4 with respect to the arm 3 (hereinafter referred to as the arm angle), and the angle γ represents the rotation angle of the bucket 4 with respect to the arm 3 (hereinafter referred to as the bucket angle). Then, the bucket tip end position 4b _{0 , 4} at the maximum dump position and maximum tilt position of the bucket 4
The rotation angle γ ^M between b _{and 1} is the rotation range of the bucket belt 4 (the range shown by diagonal lines). Note that at the maximum tilt position, the tip 4b of the bucket 4 is connected to the stopper 8 (first
(Fig.). Also, the rotation fulcrum 10 of the arm 3
The angle formed by the line segment connecting the rotation fulcrum 11 and the bucket tip 4b with respect to the extension of the line segment connecting the rotation fulcrum 11 (FIG. 1) of the bucket 4 is defined as the bucket angle γ. The bucket tilt angle at the maximum tilt position is represented by γ ^T , and the tilt angle at a position slightly before the maximum tilt position is represented by γ ^t . Therefore, at the position of this tilt angle ^γt , the tip end 4b of the bucket belt 4 does not come into contact with the stopper 8.

FIG. 3 is a block diagram of a bucket belt correction device for a loading shovel according to the present invention, in which an angle detector 30 is disposed at the rotation fulcrum 11 (FIG. 2) of the bucket belt 4, and the angle detector 30 detects the bucket rotation angle γ. It detects and outputs a corresponding bucket rotation signal e. As shown in FIG. 4, the arm operating lever 20 receives a command signal Ea of polarity and magnitude according to the operating direction and operating angle θa of the lever.
When the lever 20 is operated in the arm retraction direction (angle + θa direction), a positive polarity signal Ea is output in the arm extrusion direction (angle − θa direction).
When operated, a negative polarity signal -Ea is output. As shown in FIG. 5, the bucket operating lever 21 outputs a command signal Eb of polarity and magnitude according to the operating direction and operating angle θb of the lever.
1 outputs a positive polarity signal +Eb when operated in the bucket dump direction (arrow +θb direction), and a negative polarity signal −Eb when operated in the bucket dump direction (arrow −θb direction). The electro-hydraulic converter 23 receives the arm command signal Ea input via the amplifier 22.
Accordingly, the arm cylinder 6 is driven to control the arm 3. When the electro-hydraulic converter 23 receives the signal +Ea, it shortens the arm cylinder 6 and retracts the arm 3 (in the direction of arrow B in FIG. 1), and receives the signal -Ea.
When input, the arm cylinder 6 is extended and the arm 3 is pushed out (in the direction of arrow A in FIG. 1). In this way, the arm 3 can be controlled to be retracted or pushed out depending on the operating lever 20. The determination circuit 24 determines whether the arm 3 is retracted or pushed out, and determines whether the output signal Ea of the arm operating lever 20 is positive or negative, and when the signal is positive +Ea, that is,
Move the operating lever 20 in the arm retraction direction (arrow + θa
direction), a high level (hereinafter referred to as H level) signal is output and applied to the AND circuit 25, making the AND circuit 25 ready for operation.

The output signal Eb of the bucket operating lever 21 is applied to the contact 26a of the switch circuit 26. This switch circuit 26 contacts 26 when the output of the AND circuit 25 is at a low level (hereinafter referred to as L level).
It is switched to the a side, and when it is at H level, it is switched to the contact 26b side. This bucket command signal Eb is applied to an electro-hydraulic converter 28 via a switch circuit 26 and an amplifier 27. The electro-hydraulic converter 28 drives the bucket cylinder 6 according to the polarity of the input signal Eb, and controls the bucket 4 via the link mechanism 7. The bucket angle γ is determined by two factors, the arm angle β and the stroke of the bucket cylinder 6, and the influence of the arm angle β on the bucket angle γ is expressed by a certain function f(β).
The link mechanism provides this functional relationship.
The electro-hydraulic converter 28 extends the bucket cylinder 6 to perform tilt control of the bucket cylinder 4 when the input signal is +Eb, and shortens the bucket cylinder 6 to perform dump control when the input signal is -Eb. Angle detector 30
detects the bucket angle γ and outputs the corresponding bucket belt angle signal e. The setting device 31 sets the tilt angle γ ^t (second
This is for setting the preset tilt angle γ ^t
Outputs a reference signal Et according to. This tilt angle γ ^t
is the electrical stopper position of the bucket 4. Then, the deviation Δe between the signal e and Et is determined. This deviation Δe is the current bucket angle γ and the preset tilt angle γ ^t
(Fig. ⁶ ).
This deviation signal Δe is applied to a comparator 33 and a multiplier 34.

When the bucket angle γ reaches γ ^t , the deviation Δγ=0
Therefore, the tip of bucket 4 increases as it approaches γ ^{T beyond γ t .}
b approaches stopper 8 (FIG. 1). In this case, the deviation Δγ<0 (FIG. 6). Therefore, when the deviation Δγ becomes smaller than 0, this is detected,
By controlling the bucket cart to dump, it is possible to prevent the bucket cart 4 from colliding with the stopper 8. The setting device 32 is for setting the deviation Δγ=0, and outputs a corresponding signal E ₀ to be applied to the comparator 33. The comparator 33 compares the input signal E ₀ and Δe, and when Δe<E ₀ , that is, Δγ<0, outputs an H level signal and applies it to the AND circuit 25 .
The AND circuit 25 combines this comparator 33 and the discrimination circuit 2.
The H level signal from 4 causes it to be in the operating state.
A level signal is output to switch the switch circuit 26 to the contact 26b side. The multiplier 34 receives the deviation signal Δe
A correction signal Δe'=K·Δe (FIG. 7) obtained by multiplying K by K is output and applied to the contact 26b of the switch circuit 26.
Further, when the deviation Δγ is negative, the deviation signal becomes 1 Δe, and therefore the correction signal also becomes -Δe'. This correction signal -Δe' is then applied to an electro-hydraulic converter 28 through a switch circuit 26 and an amplifier 27. The electro-hydraulic converter 28 receives the input signal -
The bucket cylinder 6 is shortened in accordance with Δe', and the bucket 4 is controlled to dump. The larger the deviation -Δγ, the larger the correction signal -Δe′ (6th and 7th
), the deviation -Δγ and the dump correction speed are inversely proportional.
That is, the tip 4b of the bucket 4 is the stopper 8.
The closer it gets to , the faster the dump correction speed of the bucket 4 becomes.

In this way, the bucket is prevented from colliding with the stopper during the arm retraction operation.

As explained above, according to the present invention, when the bucket cart approaches the stopper during the retracting operation of the arm, by correcting the bucket cart toward the dump side, it is possible to prevent the bucket cart from colliding with the stopper. It can prevent energy loss and engine stalling due to unnecessary relief of hydraulic oil, improve operability and reduce operator fatigue, and improve cycle time even for experienced operators. It has excellent effects.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of the working machine of the loading shovel, Figure 2 is an explanatory diagram of the operation of the working machine in Figure 1, and Figure 3 is an explanatory diagram of the working machine of the loading shovel.
The figure is a block diagram showing an embodiment of the bucket belt correction device for a loading shovel according to the present invention, and FIGS. 4 and 5 are diagrams showing the relationship between the lever angle of the operating lever shown in FIG. 3 and the command signal. , FIG. 6 is a diagram showing the relationship between the bucket angle and the deviation, and FIG. 7 is a diagram showing the relationship between the bucket belt angle and the correction signal. DESCRIPTION OF SYMBOLS 1...Work equipment, 2...Boom, 3...Arm, 4...Bucket, 5, 6...Cylinder, 20, 21...Operation lever, 23, 28...Electro-hydraulic converter, 24...Discrimination circuit, 26...Switch circuit, 30... Angle detector, 31, 32... Setting device, 33... Comparator, 34...
Multiplier.

Claims (1)

[Claims] 1. In the loading shovel bucket control, the discriminator that determines arm retraction control and the angle detector that detects the bucket tilt angle detect that the deviation between the current bucket tilt angle and the preset tilt angle is smaller than a predetermined value. When the comparator outputs the arm and the discriminator output and the comparator output are applied at the same time, a command signal corresponding to the deviation is applied to the bucket control system in place of the command signal from the bucket control lever. A bucket correction device for a loading shovel, comprising means for performing dump control.