JP2724796B2 - Turning control device for aerial work vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a swivel table which has a boom that supports a bucket at its tip and is freely rotatable and supported by a vehicle body, an oil pump driven by an engine, and an oil pump. The present invention relates to a boom turning control device for an aerial work vehicle provided with a turning drive source for turning a turning table with discharge oil of a boom.

[0002]

2. Description of the Related Art There is a well-known aerial work vehicle that supports a bucket on which a worker is mounted at the tip of a boom that can be freely raised and lowered on a swivel base. The hydraulic motor that turns the turntable of the aerial work vehicle and the hydraulic cylinder that raises and lowers the boom are driven by oil discharged from an oil pump connected to the engine.

[0003]

By the way, in such an aerial work vehicle, in order to quickly move the bucket to a target position, the rotational speed of the engine for driving the oil pump is increased and the driving speed of the swivel and the boom is increased. Is desirable. However, if the swivel speed of the swivel base is increased, even if the swivel base is stopped at the bucket storage position, the swivel base overruns due to inertia and does not stop correctly at the bucket storage position. There is a possibility that the bucket may be damaged by contact with the vehicle body.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to increase the turning speed of a turntable of an aerial work vehicle and to properly stop at a bucket storage position.

[0005]

In order to achieve the above object, a turning control device for an aerial work vehicle according to the present invention has a standing and falling free boom for supporting a bucket at a tip end of the turning control device. The aerial platform equipped with a swivel supported by the engine, an oil pump driven by the engine, and a swivel drive source for swiveling the swivel by oil discharged from the oil pump, stops the swivel at the bucket storage position. First mode selection means for switching between a stop mode in which the engine is stopped and a pass mode in which the engine passes through the bucket storage position; a high-speed mode in which the rotation speed of the engine is increased to rotate the swivel base at high speed; and a rotation in which the rotation speed of the engine is reduced. Second mode selection means for switching between a low-speed mode in which the table is turned at a low speed;
The first mode selection means selects the stop mode, and the second mode selection means
And control means for restricting an increase in the number of revolutions of the engine when the mode selecting means selects the high-speed mode.

[0006]

Embodiments of the present invention will be described below with reference to the drawings.

1 to 11 show an embodiment of the present invention. FIG. 1 is an overall perspective view of an aerial work vehicle, FIG. 2 is an overall side view of an aerial work vehicle, and FIG. FIG. 4 is an exploded perspective view of the boom, FIG. 5 is an enlarged view of part 5 of FIG. 3, and FIG.
7, FIG. 7 is an enlarged view of part 7 of FIG. 3, FIG. 8 is a hydraulic circuit diagram, FIG. 9 is an electric circuit diagram, FIG. 10 is a diagram showing an elevation angle of the boom, and FIG. It is a table explaining operation | movement.

As shown in FIG. 1, the aerial work vehicle V has a swivel 3 erected on a frame 2 on the rear side of a cab 1.
The swivel 3 has a base end of a first boom 4 pivotally supported so as to be able to swing up and down. A tip end of the first boom 4 has a base end which is pivotally supported so as to be able to swing up and down. Is provided with a bucket 6 on which an operator rides. The upper surface of the frame 2 is covered with a cover 7 except for the space where the swivel 3 is provided and the space where the bucket 6 is stored. Inside the cover 7, a hydraulic device for driving the swivel 3 and the two booms 4, 5 and a control device therefor are housed.

As shown in FIGS. 2 to 4, a swivel 3 is supported on a base 11 provided at the front of the frame 2 so as to be swivelable about a vertical axis. A worm gear 1 is provided on the output shaft of a hydraulic motor 12 as a turning drive source provided on the base 11.
3 is fixed, and the worm gear 13 is
The turning table 3 is turned by being engaged with a worm wheel 14 fixed to the lower end of the turning table 3.

At the upper end of the swivel base 3, a first horizontally extending
A shaft 15 is fixed, and the first shaft 15
The base end of the first boom main body 16 constituting the skeleton of the boom 4 is pivotally supported. A second boom main body 18 constituting the skeleton of the second boom 5 is pivotally supported by a second shaft 17 extending in the horizontal direction at the tip of the first boom main body 16. The second shaft 17 is
The first boom body 16 and the second boom body 18 are both rotatable relative to each other. At the end of the second boom main body 18, a third shaft 19 as a bucket support shaft is rotatably and horizontally supported relative to the second boom main body 18, and the third shaft 19 The lower part is fixed.

A first hydraulic cylinder 21 for connecting a bracket 20 provided at a base end of the first boom main body 16 to the swivel base 3.
As a result, the first boom 4 is driven to rise and fall with respect to the swivel 3. Further, a link 23 pivotally supported by a pin 22 at the distal end of the first boom main body 16 and a link 25 pivotally supported by a pin 24 at the base end of the second boom main body 18 are connected by a pin 26, and the link 23 and the first boom are connected. By connecting the bracket 27 provided at the intermediate portion of the main body 16 with the second hydraulic cylinder 28, the second boom 5 is driven to stand up and down with respect to the first boom 4.

Next, the structure of the bucket horizontal holding means 29 for holding the bucket 6 in a horizontal posture will be described.

A pair of left and right sprockets 30, 30 fixed to a first shaft 15 integral with the swivel 3;
A pair of left and right sprockets 31 fixed to a second shaft 17 that is rotatable relative to both the
A pair of first cable members 32, 32 are wound between the first cable members 31. Each of the first cable members 32 includes a chain 33 that meshes with the sprocket 30, a chain 34 that meshes with the sprocket 31, and two rods 35, 35 that connect between both ends of the chains 33, 34. You.

Another pair of left and right sprockets 36, 36 fixed to the second shaft 17 and a third shaft 19 integrated with the bucket 6.
A pair of second cable members 38, 38 are wound around a pair of left and right sprockets 37, 37 that are fixed to the pair. Each of the second cable members 38 includes a chain 39 that meshes with the sprocket 36, a chain 40 that meshes with the sprocket 37, and two rods 4 that connect between both ends of the chains 39 and 40.
1, 41.

A plurality of brackets 42 provided on both right and left sides of the first boom body 16 are provided with the first cable members 32, 3 respectively.
2 are supported.
A plurality of brackets 44 provided on both left and right sides of the boom body 18 have covers 4 covering the second cable members 38, 38.
5,45 are supported.

Thus, the swivel 3 is moved by the first hydraulic cylinder 21.
When the first boom 4 is raised and lowered with respect to the first boom, and the second boom 5 is raised and lowered with respect to the first boom 4 by the second hydraulic cylinder 28, the first cable members 32 1
The second shaft 17 is held in the same phase with respect to the shaft 15, and the third shafts
The shaft 19 is kept in phase. As a result, the third shaft 19
Is held at a phase in which the bucket 6 is in a horizontal attitude with respect to the first shaft 15, that is, the swivel 3.

As shown in FIG. 10, the up-and-down angle α of the first boom 4 is up to 65 ° counterclockwise from the stored state (see FIG. 2) with respect to the vehicle body. The possible angle β is up to 155 ° counterclockwise with respect to the first boom 4. Therefore, the first boom 4 and the second boom
When the boom 5 is erected together, the undulation angle of the second boom 5 based on the stored state is obtained by adding β to α.
Its maximum value is 220 °.

As shown in FIG. 5, in order to detect the turning position of the swivel base 3, the swivel base 3 supports a swing detecting means 51 comprising a limit switch. On the other hand, the base 11 is provided with a cam 54 that can abut on the operator 53 of the turning detecting means 51. When the swivel base 3 is at the bucket storage position, that is, when the first boom 4 is at the position shown in FIG. 2 facing the rear of the vehicle body, the cam 54 comes into contact with the operating element 53 and a contact, which will be described later, is switched.

As shown in FIG. 6, the first boom main body 16 is provided with first up-and-down detecting means 55 composed of a limit switch for detecting the up-and-down angle of the first boom 4. The contactable cam 57 is one of the first
It is provided on the rod 35 of the cable body 32. The cam 57 has a predetermined length, and when the undulation angle α of the first boom 4 is less than 28 °, the actuator 56 and the cam 57 are separated from each other, and the contact of the first undulation detecting means 55 is opened. I have. When the undulation angle α of the first boom 4 becomes 28 ° or more, the actuator 56 and the cam 57 come into contact, and the contact of the first undulation detection means 55 is closed.

As shown in FIG. 7, the second boom main body 18 is provided with a second up-and-down detecting means 58 composed of a limit switch for detecting the up-and-down angle of the second boom 5. The contactable cam 60 is one of the second
It is provided on the rod 41 of the cable body 38. The cam 60 has a predetermined length, and when the sum α + β of the undulation angle α of the second boom 4 and the undulation angle β of the second boom 5 is less than 52 °, the actuator 59 and the cam 60 are separated. , Α + β is 52 °
Then, the actuator 59 and the cam 60 come into contact with each other. As described above, since the second cable body 38 is moved by the undulation of either the first boom 4 or the second boom 5, the second undulation detecting means 58 detects the sum α + β of the undulation angles of both the booms 4 and 5. I do.

FIG. 8 shows a hydraulic circuit for operating the hydraulic motor 12, the first hydraulic cylinder 21, and the first hydraulic cylinder 28.

Electromagnetic valves 73, 74 and 75 are provided between an oil pump 72 for pumping hydraulic oil from an oil tank 71 and the hydraulic motor 12, the first hydraulic cylinder 21 and the second hydraulic cylinder 28, respectively. When the solenoid 73L of the solenoid valve 73 is excited, the hydraulic motor 12 is driven to turn the swivel 3 to the left, and when the solenoid 73R is excited, the hydraulic motor 12 is driven in the reverse direction to turn the swivel 3 to the right. When the solenoid 74U of the solenoid valve 74 is excited, the first hydraulic cylinder 21 is driven to raise the first boom 4, and when the solenoid 74D is excited, the first hydraulic cylinder 21 is driven in the opposite direction and the first boom 4 falls. . Solenoid valve 75
When the solenoid 75U is excited, the second hydraulic cylinder 28
Is driven to raise the second boom 5, and the solenoid 75D
Is excited, the second hydraulic cylinder 28 is driven in the reverse direction, and the second boom 5 falls down.

Engine 85 for driving oil pump 72
A rotary solenoid 90 is connected to the throttle lever 86 for controlling the rotation speed of the engine 85. When the solenoid 90 is excited, the rotation speed of the engine 85 increases by a predetermined value and the discharge amount of the oil pump 72 increases.

FIG. 9 shows an electric circuit of a control device 81 for operating the solenoid valves 73, 74, 75.

Reference numeral 51 denotes the turning detecting means. The NO contact is closed when the swivel 3 is in the storage position, and the NC contact is closed when the swivel 3 is in a position other than the storage position. Reference numeral 55 denotes the first undulation detecting means, and the contact is opened when the undulation angle α of the first boom 4 is less than 28 °.
Closes at 28 ° or more. Reference numeral 58 denotes the second undulation detecting means, and when the sum α + β of the undulation angle α of the first boom 4 and the undulation angle β of the second boom 5 is less than 52 °, the NO contact is closed and α + β becomes 52 NC in the state above °
The contacts close.

The switches 82L and 82R are for turning the turntable 3 to the left and to the right, respectively, and are connected to the solenoids 73L and 73D of the solenoid valve 73, respectively. The switches 83U and 83D are for raising and lowering the first boom 4, respectively, and are connected to the solenoids 74U and 74D of the solenoid valve 74, respectively. The switches 84U and 84D are for raising and lowering the second boom 5, respectively.
5U and 75D respectively.

Reference numeral 88 denotes a first mode selection switch. When the first mode selection switch 88 is closed, the swivel 3 passes through the bucket storage position without stopping (passing mode), and when it is opened. The swivel 3 stops at the bucket storage position (stop mode). Reference numeral 89 denotes a second mode selection switch.
When the valve 9 is closed, the solenoid 90 is excited to increase the rotation speed of the engine 85 (high-speed mode), and when opened, the solenoid 90 is demagnetized and the rotation speed of the engine 85 is reduced (low-speed mode).

Next, the operation of the embodiment of the present invention having the above-described configuration will be described.

FIG. 11 shows a table based on the turning position of the swivel 3 and the undulation angles of the first boom 4 and the second boom 5.
Indicates whether the hydraulic motor 12 for driving the swivel 3, the first cylinder 21 for driving the first boom 4, and the second cylinder 28 for driving the second boom 5 are operable or inoperable. is there. In the table, ○ indicates that the operation is permitted, and X indicates that the operation is restricted.

That is, the undulation angle α of the first boom 4 is 28 °
In the case of the above, or when the sum α + β of the undulation angle α of the first boom 4 and the undulation angle β of the second boom 5 is 52 ° or more, both the booms 4 and 5 and the bucket 6 Since there is no possibility of being damaged by contact with the cover 7, the driving of the first boom 4, the second boom 5, and the swivel 3 are all permitted. In addition, when the swivel 3 is at the storage position of the bucket 6, the undulation angle α of the first boom 4 is less than 28 °, and the undulation angle α of the first boom 4 and the undulation angle of the second boom 5 When the sum α + β is less than 52 °, the swivel of the swivel base 3 is restricted in order to prevent the booms 4, 5 and the bucket 6 from coming into contact with the cab 1 and the cover 7 and being damaged. You. Furthermore, when the swivel 3 is not in the storage position of the bucket 6, the undulation angle α of the first boom 4 is less than 28 °, and the undulation angle α of the first boom 4 and the undulation angle of the second boom 5 When the sum α + β is less than 52 °,
In order to prevent the booms 4 and 5 and the bucket 6 from being damaged by contacting the cab 1 and the cover 7, the turning of the swivel 3 and the falling of the booms 4 and 5 are restricted.

Hereinafter, each of the above cases will be described with reference to the electric circuit diagram of FIG. Note that the first mode selection switch 88 is closed, the swivel 3 is in a state of passing the bucket storage position (passing mode), and the second mode selection switch 89 is open to rotate the engine 85. It is assumed that the number is in a low state (low-speed mode). Irregularity of the first boom 4 irrespective of the position of the swivel 3
The degree α is 28 ° or more, or the undulation angle of the first boom 4
The sum α + β of the degree α and the undulation angle β of the second boom 5 is 52 °
In this case (see the column “A” in the table), in this case, at least one of the contact point of the first undulation detection means 55 and the NC contact point of the second undulation detection means 58 is closed. The first boom 4 and the second boom 5 can be freely raised and lowered by operating the switches 83U and 83D and the switches 84U and 84D on either side of the NO contact and the NC contact. Further, regardless of the position of the swivel base 3, the swivel base 3 can be freely swung right and left by operating the switches 82L and 82R. The undulation angle α of the first boom 4 is less than 28 °, and
Angle of the first boom 4 and angle of the second boom 5
β + α is less than 52 °, and the turntable 3 is
In the case of being in the pocket storage position (see the "B" column in the table), in this case, the contact of the first undulation detection means 55 is opened, the NO contact of the second undulation detection means 58 is closed, and the turning detection means 51 NO contact is closed. As a result, the first boom 4 and the second boom can be freely raised and lowered by operating the switches 83U and 83D and the switches 84U and 84D. Also, the switches 82L, 8
Even if the 2R is operated, the turntable 3 cannot be turned. The undulation angle α of the first boom 4 is less than 28 °, and
Angle of the first boom 4 and angle of the second boom 5
β + α is less than 52 °, and the turntable 3 is
In the case other than the pocket storage position (see the column "C" in the table) In this case, the contact of the first undulation detection means 55 is opened, the NO contact of the second undulation detection means 58 is closed, and the turning detection means The NO contact 51 is opened. As a result, the relay 86 is demagnetized and the relay contact 87 is closed. Therefore, only the upright of the first boom 4 by the operation of the switch 83U and the uprighting of the second boom 5 by the operation of the switch 84U are allowed, and the first boom 4 and the second boom 5 fall, and the swivel 3 rotates. Is regulated.

As described above, when there is a possibility that the first boom 4, the second boom 5 and the bucket 6 come into contact with the cab 1 or the cover 7, the swivel of the swivel 3 and the booms 4 and 5 By properly regulating the lodging, the occurrence of the contact can be prevented beforehand.

When the passage mode is selected by closing the first mode selection switch 88 and the high speed mode is selected by closing the second mode selection switch 89, the solenoid 90 is energized. When the throttle lever 86 is driven, the rotation speed of the engine 85 increases and the oil pump 72
Discharge oil amount increases. As a result, it is possible to increase the turning speed of the turntable 3 and the undulating / falling speed of the booms 4 and 5.

When the swivel base 3 is stopped at the bucket storage position in order to store the bucket 6 and finish the operation, the first mode selection switch 88 is opened to select the stop mode. As a result, when the NC contact of the swing detecting means 51 is closed, that is, when the swivel 3 is not at the bucket storage position, the swivel 3 can freely rotate, but the swivel 3 reaches the bucket storage position. NO of turning detection means 51
When the contacts are closed, the swivel 3 stops at the bucket storage position. At this time, the second mode selection switch 8
When 9 is in the low-speed mode (open) and the inertia of the swivel 3 is small, the swivel 3 stops at the bucket storage position without overrun.

By the way, the first mode selection switch 88
When the second mode selection switch 89 is in the high-speed mode (closed) and the inertia due to the swivel of the swivel 3 is large, the stop mode is set to the stop mode (open) to stop the swivel 3. The swivel 3 may overrun the bucket storage position. However, when the first mode selection switch 88 is in the stop mode, the solenoid 90 is not excited even if the second mode selection switch 89 is set to the high-speed mode. Therefore, the turning speed of the turntable 3 is kept low without increasing the rotation speed of the engine 85, and the turntable 3
Can stop correctly at the bucket storage position without overrun.

During normal work, the second mode selection switch 89 can be set to the high-speed mode to improve work efficiency, and the swivel 3 is stopped at the bucket storage position to complete the work. In some cases, regardless of the position of the second mode selection switch 88, the swing speed of the swivel base 3 can be reduced to correctly stop at the bucket storage position.

After the first mode selection switch 88 is set to the stop mode and the swivel base 3 is stopped, the first mode selection switch 88 is set so that the swivel base 3 can be swung when the next operation is started. Must be returned to the passing mode. When the bucket is stored, the first mode selection switch 88 is returned to the passing mode.
May automatically return to the pass mode.

Although the embodiments of the present invention have been described in detail, the present invention is not limited to the above embodiments, and various design changes can be made.

[0039]

As described above, according to the present invention, when the stop mode is selected by the first mode selection means to stop the swivel base at the bucket storage position, the second swivel base is rotated at a high speed. Even if the high-speed mode is selected by the mode selection means, the increase in the engine speed is restricted. Thus, the turning speed of the swivel base is maintained at a low speed, the swivel base is correctly stopped at the bucket storage position without overrunning, and the inconvenience of the boom or bucket contacting the vehicle body can be reliably avoided. .

[Brief description of the drawings]

FIG. 1 is an overall perspective view of an aerial work vehicle.

FIG. 2 is an overall side view of an aerial work vehicle.

FIG. 3 is an enlarged view of a main part of FIG. 2;

FIG. 4 is an exploded perspective view of the boom.

FIG. 5 is an enlarged view of part 5 of FIG.

FIG. 6 is an enlarged view of part 6 of FIG.

FIG. 7 is an enlarged view of part 7 of FIG.

FIG. 8 is a hydraulic circuit diagram.

FIG. 9 is an electric circuit diagram

FIG. 10 is a diagram showing an elevation angle of a boom.

FIG. 11 is a table for explaining the operation of the swivel base and the boom.

[Explanation of symbols]

Reference Signs List 3 swivel base 4 first boom (boom) 5 second boom (boom) 6 bucket 12 hydraulic motor (turning drive source) 72 oil pump 81 controller (control means) 85 engine 88 first mode selection switch (first) 89 second mode changeover switch (second mode selection means)

Claims (1)

(57) [Claims] 1. An upright supporting a bucket (6) at its tip.
A swiveling base (3) having a boom (4, 5) which can be freely tilted and supported by a vehicle body so as to be swivelable; an oil pump (72) driven by an engine (85); and an oil pump (7)
In the aerial work vehicle provided with a turning drive source (12) for turning the swivel (3) by the discharged oil of 2), the stop mode for stopping the swivel (3) at the bucket storage position and the bucket storage position are set as follows. A first mode selection means (88) for switching between a passing mode and a high speed mode for increasing the rotation speed of the engine (85) to turn the swivel (3) at a high speed; A second mode selecting means (89) for switching between a low speed mode in which the swiveling base (3) is turned at a low speed by decreasing the speed, and a first mode selecting means (88) for selecting a stop mode;
And a control means (81) for restricting an increase in the engine speed when the second mode selection means (89) selects the high-speed mode. .