JP3379799B2 - Bucket leveler device for industrial vehicles - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bucket leveler for an industrial vehicle such as a shovel loader . 2. Description of the Prior Art This kind of bucket leveler device, the
The applicant has filed Japanese Patent Application No. 63-6837 (Japanese Unexamined Patent Application Publication No.
No. 82419) . The bucket leveler device of the above application facilitates rake after loading and discharging,
The hydraulic system is automatically controlled so that the bottom of the bucket becomes horizontal on the ground as the bucket descends. [0003] However, in the conventional bucket leveler device, after the earth and sand contained in the bucket is discharged in a full dump state on a dump truck bed or the like, the bucket leveler device is stopped with the boom stopped. When the is operated, the rotation speed of the bucket increases, and when the bucket stops, there is a problem that a large impact is generated in the upward direction of the vehicle body. [0004] If the bucket leveler device is operated after the boom is lowered to prevent this, the bucket lever and the boom lever must be frequently changed, and the operation becomes complicated. For this reason, in the prior art, the boom is lowered immediately after the operation of the bucket leveler device, and the operation of the leveler device is completed while the boom is lowered, so as to reduce the impact at the time of stopping the bucket or reduce the rotation speed of the engine. There was a problem that required an operation such as reducing the rotation speed of the bucket. The present invention has been made in order to solve such a problem, and provides a bucket leveler device for an industrial vehicle in which a bucket can be stopped at a horizontal position by a simple operation of simply lowering the boom after discharging. It is intended for. According to the present invention, in order to achieve the above object, a bucket that can be dumped and tilted by a bucket cylinder is provided at the tip of a boom that can be vertically rotated by a boom cylinder. In an industrial vehicle, a floating position detector for detecting a floating position of a boom operation valve for controlling the boom cylinder, a detent mechanism for holding a boom lever in the floating position, and a boom angle detector for detecting a rotation angle of the boom And a boom stop angle storage means in which a stop position of the boom is stored in advance, an electromagnetic valve for controlling the bucket cylinder in a tilt direction, and a bucket cylinder position detector for detecting a position of the bucket cylinder. The solenoid valve is turned on by the signal from the above to start the tilting of the bucket, and the calculating means Calculate the deviation between the boom angle and the boom stop angle, turn off the solenoid valve with turning on the bucket cylinder position detector, stop the bucket tilt, and when the boom reaches the stop position, turn on the detent mechanism. Is canceled. According to the present invention, with the above-described structure, the inside of the bucket
After discharging the soil, operate the boom lever to the floating position and move the boom
The bucket automatically moves to the horizontal position
It is tilted to be easy to operate,
The bucket is tilted during boom lowering, so the bucket
It is possible to reduce the impact generated at the time of stopping. Also boom
Whether bucket leveler operation is performed during descent
Boom descent and leveler operation in a short time and efficiently
Hydraulic pressure loss during boom descent.
Wear. A first embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a circuit diagram of the bucket leveler device, FIG. 2 is a flowchart showing the operation, and FIG. 3 is a diagram showing the operation.
In FIG. 1, reference numeral 1 denotes a boom cylinder provided in a bucket working machine of an industrial vehicle (not shown), 2 denotes the bucket cylinder, and 3 denotes a hydraulic pump. The hydraulic oil discharged from the hydraulic pump 3 is:
The bucket operation valve 4 is supplied to the bucket cylinder 2 via the bucket operation valve 4 and to the boom cylinder 1 via the bucket operation valve 4 and the boom operation valve 5.
A bucket lever neutral detector 7 for detecting that the bucket lever 4a has reached the neutral position, and a boom operating valve 5 having a floating position detector 8 for detecting that the boom lever 5a has been operated to the floating position. However, a bucket cylinder position detector 9 is provided in the vicinity of the bucket cylinder 2, and a switch 10 is activated by a signal from the bucket lever neutral detector 7, and a switch 11 is activated by a signal from the bucket cylinder position detector 9. At the same time, the signal from the floating position detector 8 is input to the calculating means 12. The switches 10 and 11 are interposed in series between the arithmetic means 12 and the amplifier 13 for operating the electromagnetic valve 14, and the electromagnetic valve 14 is interposed between the hydraulic pump 15 and the bucket cylinder 2. On the other hand, the difference between the boom angle θ ₀ from the boom angle detector 18 and the boom angle θ _0m from the boom stop angle storage means 19 is input to the calculating means 12. A control signal is output to the detent mechanism 21 via the output device 20. The detent mechanism 21 is provided near the boom lever 5a, and holds the boom lever 5a at a floating position, and releases the holding together with the input of a signal. Next, the operation will be described with reference to FIGS. When the boom lever 5a is moved to the floating position in a bucket full dump state after the earth and sand contained in the bucket is discharged to a dump truck or the like, the boom starts to descend naturally by its own weight, and a signal from the floating position detector 8 is output by the arithmetic means. When the boom is lowered, hydraulic oil is supplied from the hydraulic pump 15 to the bottom side of the bucket cylinder 2, and the bucket starts to tilt in the horizontal direction from the full dump state. The change in the boom angle due to the boom descent is as follows:
In step 101 of the flowchart shown in FIG. 2, the boom angle is read by the boom angle detector, and in step 102 , it is compared with the stop angle θ _0m described in the boom stop angle storage means 19 to calculate the deviation Δθ ₀ . And step 1
At 03, it is determined whether the deviation Δθ ₀ is greater than 0, and if NO, the process proceeds to step 104 to release the detent mechanism, and then returns to step 101 , and again proceeds from step 101 to step 103. If YES in step 103, the flow advances to step 105 to determine whether the boom lever 5a is at the floating position. If YES, the flow advances to step 106 to determine whether the bucket cylinder position detector 9 is on. Is determined. In the case of NO, the process proceeds to step 107, where the solenoid valve 14 is kept on and the process returns to step 101. The above operation is repeated, and in the case of YES in step 106, the solenoid valve 14 is turned off in step 108 to tilt the bucket. To stop. Thereafter, the boom further descends, and when it reaches the stop position _θ0m stored in the boom stop angle storage means 19, a control signal is output from the calculating means 12 to the detent mechanism 21 and the holding of the boom lever 5a is released. When the boom lever 5a reaches the neutral position, the boom is stopped. Thereafter, the boom lever 5a is operated to further lower the boom so that the bottom surface of the bucket is grounded,
It is possible to shift to the next scooping operation. As described above, simply by operating the boom lever 5a to the floating position after discharging, the bucket can be automatically stopped horizontally at a certain height above the ground. FIG. 3 shows a change in the angle of the bucket when the boom is naturally lowered from the discharging position. In this figure, point a is when the boom lever 5a is in the floating position, the bucket starts tilting from the dump position as shown in b, and at point c the bucket cylinder position detector 9 is turned on to complete the tilt. . Thereafter, the boom further descends, stops descending at point d, and then reaches the ground at point e by a lowering operation by the boom lever 5a. In the first embodiment, the bucket operating valve 4
In the case where the boom operation valve 5 is operated by levers 4a and 5a, the present invention can also be applied to a hydraulic circuit in which the bucket operation valve 4 and the boom operation valve 5 are pilot-controlled as shown in FIG. In the second embodiment, a shuttle valve 26 is provided in the pilot circuit of the pilot operation valve 25 in place of the bucket tilt solenoid valve 14 to perform interrupt control. Further, in the case of the second embodiment, since the tilt operation is performed by the bucket operation valve 4, the tilt flow rate is determined by the discharge amount of the hydraulic pump. For this reason, there is a case where the tilt of the bucket cannot keep up while the boom descends to the stop position. In order to prevent this, in the second embodiment, a proportional pressure reducing valve 23 is provided in the pilot circuit on the boom lowering side to reduce the natural descent speed of the boom, thereby securing the tilt time of the bucket. The operation of the second embodiment is shown in the flowchart of FIG. In this figure, step 105 '
Other than the above, the description is omitted because it is the same as the first embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a circuit diagram showing a bucket leveler device for an industrial vehicle according to a first embodiment of the present invention. FIG. 2 is a flowchart showing an operation of the industrial vehicle bucket leveler according to the first embodiment of the present invention. FIG. 3 is a diagram showing an operation of the bucket leveler device for an industrial vehicle according to the first embodiment of the present invention. FIG. 4 is a circuit diagram showing a bucket leveler device for an industrial vehicle according to a second embodiment of the present invention. FIG. 5 is a flowchart showing the operation of the bucket leveler device for an industrial vehicle according to the second embodiment of the present invention. [Description of Signs] 1 Boom cylinder 2 Bucket cylinder 4 Bucket operating valve 5 Boom operating valve 5a Boom lever 8 Floating position detector 9 Bucket cylinder position detector 12 Calculation means 14 Solenoid valve 21 Detent mechanism

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) E02F 3/43

Claims (1)

( 1) An industrial vehicle provided with a bucket capable of being dumped and tilted by a bucket cylinder (2) at a tip of a boom rotatable vertically by a boom cylinder (1) . A floating position detector (8) for detecting a floating position of a boom operating valve (5 ) for controlling the boom cylinder (1) , and a detent mechanism (21) for holding a boom lever (5a) at the floating position.
And a boom angle detector (18) for detecting a rotation angle of the boom
Boom stop angle storage means (19) in which the stop position of the boom is stored in advance, and a solenoid valve (14) for controlling the bucket cylinder (2) in the tilt direction and a bucket cylinder for detecting the position of the bucket cylinder (2) Equipped with a position detector (9) ,
According to the signal from the floating position detector (8) , the solenoid valve (1
4) is turned on to start the tilting of the bucket, the deviation between the boom angle and the boom stop angle is calculated by the calculating means (12) , and the solenoid valve (14 ) is turned on when the bucket cylinder position detector (9) is turned on. ) Is turned off, the tilt of the bucket is stopped, and the detent mechanism (21) is released when the boom reaches the stop position.