JPH0213437Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a hydraulic circuit for a leveling device for a bucket for carrying a worker, which is attached to the tip of a boom of a mobile crane.

(Prior Art) A mobile crane equipped with a boom that is mounted on a vehicle so as to be able to swing and raise and lower, and that is driven to swing by a swing hydraulic motor and to be lifted and lowered by a hydraulic cylinder for hoisting, is capable of swinging and hoisting the boom. Since the tip of the boom can be moved to an arbitrary high place, in recent years, a bucket for high-place work has been attached to the tip of the boom and used as a high-place work vehicle. By the way, this type of bucket for high-altitude work is tiltably attached to the tip of the boom via a horizontal support shaft perpendicular to the boom's ups and downs trajectory plane, and is always kept horizontal by a leveling device powered by hydraulic pressure. It is installed in such a way that it is in good condition. Conventionally, refueling the leveling device of buckets for high-altitude work was
The mobile crane was equipped with a hydraulic pump dedicated to the leveling device, and oil was supplied from this pump.

On the other hand, a mobile crane suspends a load from the tip of the boom and rotates and raises and lowers the boom.In order to increase work efficiency, the speed of rotation and lowering of the boom is much faster than that of a general aerial work vehicle. It has become a thing. In particular, there is a problem that the turning speed is too fast when performing work at high places by attaching a bucket for work at high places to the tip of the boom of a mobile crane. When doing so, it was necessary to be careful not to fully open the swing operation valve that controls the rotation of the swing hydraulic motor.

(Problems to be solved by the present invention) As described above, when a mobile crane is used as an aerial work vehicle, it has conventionally been necessary to provide a hydraulic pump exclusively for the leveling device of the bucket for aerial work, and There is a problem in that the swing operation valve that controls the rotation of the hydraulic motor must be operated with care so that the boom swing speed does not become excessive.

The present invention aims to provide a novel oil supply circuit for a leveling device for a bucket for high-altitude work installed on a mobile crane, which eliminates the problems of the prior art described above.

(Means for solving the problems) In order to achieve the above object, the present invention is constructed as follows. That is, a mobile crane equipped with a boom that is mounted on a vehicle so as to be able to swing and raise and lower, and that is driven to swing by a swing hydraulic motor and to be driven to rise and fall by a hoisting hydraulic cylinder, and in particular, the swing hydraulic motor is rotated by a swing hydraulic pump. The luffing hydraulic cylinder is configured to be driven by pressure oil supplied via the hoisting operation valve from a hydraulic pump other than the swing hydraulic pump. A high location of a mobile crane that is freely maintained in a horizontal state by a leveling device powered by hydraulic pressure, which is freely attached to the tip of the boom via a horizontal support shaft perpendicular to the undulation trajectory plane of the boom. In the oil supply circuit for the leveling device of the work bucket, a switching valve is interposed in the swing pump oil passage connecting the swing hydraulic pump and the swing operation valve, and one of the ports on the outflow side of the oil supply circuit is provided. A flow divider valve connected to the downstream side of the switching valve in the swing pump oil passage, the other of its outflow side ports connected to the leveling device, and its inflow side port connected to the switching valve, and the switching valve is configured to be switchable between a position where the swing pump oil passage is communicated with the swing pump oil passage and a position where the swing pump oil passage is blocked and a front stage of the switching valve in the swing pump oil passage is connected to the inflow side port of the diverter valve. A refueling circuit for a leveling device for a bucket for high-altitude work installed on a mobile crane.

(Function) The refueling circuit for the leveling device of the bucket for high-altitude work that is attached to the mobile crane of the present invention having the above-mentioned configuration can be installed on the top of the boom of the mobile crane. When the crane is used as an aerial work vehicle, the pressure oil for the leveling device of the bucket for aerial work is diverted from the hydraulic pressure for the swing hydraulic motor. This eliminates the need to provide a pump and allows the swinging speed of the boom to be reduced when a bucket for high-altitude work is attached.

(Example) Hereinafter, an example of a refueling circuit for a leveling device for a bucket for high-altitude work mounted on a mobile crane according to the present invention will be described in detail with reference to FIGS. 1 and 2.

First, a mobile crane equipped with a bucket for high-altitude work to which the present invention is applied will be explained based on FIG. In FIG. 1, A is a mobile crane, and mobile crane A is mounted on a vehicle 1 so as to be able to swing and raise and lower. It is equipped with a boom 4. 5
is a leveling device 7 which is tiltably attached to the tip of the boom 4 via a horizontal support shaft 6 perpendicular to the undulation trajectory plane of the boom 4 and whose power source is hydraulic pressure.
This is a bucket for high-altitude work that is always maintained in a horizontal position. The mobile crane A can perform normal crane work by removing the bucket cart 5 for high-altitude work from the tip of the boom 4 and then installing a hook block (not shown) at the tip of the boom 4. The leveling device 7 includes a tilt detector 8 that is attached to the bucket cart 5 for high-altitude work and detects the inclination state of the bucket cart 5, and a tilt detector 8 that is attached to the bucket cart 5 for high-altitude work.
When the tilt detector 8 detects the tilt of the bucket 5 for high-altitude work, the hydraulic cylinder 9 is operated by a signal from the tilt detector 8. and a control valve 10 for restoring the bucket cart 5 for high-place work to a horizontal state.

The swing hydraulic motor 2, as shown in FIG.
It is driven by pressure oil supplied from a swing hydraulic pump 11 provided on the vehicle 1 side through a swing operation valve 12. 13 is a swing pump oil passage that connects the swing hydraulic pump 11 and the swing operation valve 12 and supplies pressure oil generated by the swing hydraulic pump 11 to the swing operation valve 12. As shown in FIG.
It is designed to be driven by pressure oil supplied from the ground through the up-and-down operation valve 15. Reference numeral 16 denotes a winch operation valve provided in the carry-over circuit of the luffing operation valve 15, and this winch operation valve 16
is used to drive and control a hydraulic winch (not shown) that drives up and down a hook block (not shown) suspended from the tip of the boom 4 when the mobile crane A performs crane work. The reason why the hydraulic drive circuit for swinging is made independent from the hydraulic drive circuit for luffing or the hydraulic drive circuit for winch is to prevent the swinging drive speed from changing even if the swinging drive and winch drive are performed during swing drive. It's for a reason.

Based on FIG. 2, a refueling circuit for a leveling device for a bucket for high-altitude work mounted on a mobile crane according to the present invention will be explained. Leveling device 7
The driving pressure oil is supplied to the control valve 10 of the leveling device 7, and this oil supply circuit for the leveling device includes a switching valve 17 installed in the swing pump oil passage 13, and a port 18 on the outflow side thereof. is connected to the rear stage of the switching valve 17 in the orbiting pump oil passage 13, its outflow side port 19 is connected to the control valve 10 of the leveling device 7, and its inflow side port 20 is connected to the switching valve 17. It consists of The switching valve 17 is connected to the swing pump oil passage 13.
and a position where the rotary pump oil passage 13 is blocked and the front stage of the switching valve 17 in the rotary pump oil passage 13 is connected to the inflow side port 20 of the diverter valve 21. are doing. In addition, 22 is an oil passage connecting between the switching valve 17 and the inflow side port 20 of the diversion valve 21, and 23 is
An oil passage 24 connecting the outflow side port 18 of the diverter valve 21 and the rear stage of the switching valve 17 of the swing pump oil passage 13;
is an oil passage connecting between the outflow side port 19 of the flow dividing valve 21 and the control valve 10 of the leveling device 7.
25 is a flexible hose installed in the oil passage 24. Reference numeral 26 denotes a tank oil path for returning the return oil from the control valve 10 of the leveling device 7 to a tank 27 provided on the vehicle 1 side. 28 is a flexible hose installed in the tank oil path 26.

Next, the effect will be explained. When performing crane work with mobile crane A, the switching valve 17 installed in the swing pump circuit 13 is set to the position to supply the entire amount of oil discharged from the swing pump 11 to the swing operation valve 12 to perform crane work. However, when the mobile crane A is used as an aerial work vehicle by attaching the bucket 5 to the tip of the boom 4 of the mobile crane A, the oil passage 2 is connected to the control valve 10 of the leveling device 7.
4 and the tank oil line 26, the switching valve 17 is switched to the position, and the oil discharged from the swing pump 11 is diverted by the diversion valve 21, and a part of the discharge oil is sent to the leveling device 7 and the rest is transferred to the swing operation valve 12. supply to. At this time, the oil discharged from the swing hydraulic pump 11 can be used as driving pressure oil for the leveling device 7, and the pressure oil supplied to the swing operation valve 12 can be used during crane work of the mobile crane (switching valve 17
As a result, the swinging speed of the boom 4 is reduced, and the danger of the worker riding on the bucket 5 being thrown off by the swinging movement of the boom 4 is avoided.

In the above embodiment, the leveling device 7
The return oil from the control valve 10 is directly returned to the tank 27 via the tank oil path 26.
When installing a hydraulic work machine such as a small hydraulic winch or a hydraulic swing drive device for the bucket cart 5 for working at heights (one that rotates the bucket cart 5 for working at heights at the tip of the boom 4), etc., to the bucket cart 5 for working at heights,
As shown in FIG. 3, the return oil from the control valve 10 may be returned to the tank oil path 26 through the operating valves of these hydraulic drive devices.

(Effects) The refueling circuit for the leveling device for the bucket belt for high-altitude work installed on the mobile crane of the present invention, which is constructed and operates as described above, has the bucket belt for high-altitude work attached to the tip of the boom 4 of the mobile crane A. When using this as a high-altitude work vehicle, pressure oil for the leveling device can be taken out from the swing hydraulic pump by simply switching the switching valve 17, so it can be manufactured at low cost, and the boom can be used for high-place work. Since it can reduce the turning speed of the machine, it has an excellent effect in ensuring safety when working at heights.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing a state in which a bucket for high-altitude work is attached to a mobile crane, and FIGS. 2 and 3 are leveling devices for a bucket for high-altitude work that is attached to a mobile crane according to the present invention. FIG. 2 is an explanatory diagram of a fuel supply circuit. Vehicle...1, Hydraulic motor for swinging...2, Hydraulic cylinder for luffing...3, Boom...4, Operating valve for swinging...1
2. Lifting operation valve…15. Hydraulic pump for swinging…1
1. Horizontal support shaft...6, Leveling device...7, Bucket for high-place work...5, Swing pump oil line...13, Switching valve...17, Diversion valve...21.

Claims (1)

[Scope of utility model registration request] A mobile crane equipped with a boom that is mounted on a vehicle so as to be able to swing and raise and lower, and that is driven to swing by a swing hydraulic motor and to be driven to rise and fall by a hoisting hydraulic cylinder, in particular, the swing hydraulic motor is operated by a swing hydraulic pump. Movement driven by pressure oil supplied via a valve, and configured such that the undulation hydraulic cylinder is driven by pressure oil supplied via a undulation operation valve from a hydraulic pump other than the swing hydraulic pump. A high place of a type crane that is tiltably attached to the tip of the boom via a horizontal support shaft perpendicular to the undulation trajectory plane of the boom and that is always maintained in a horizontal state by a leveling device powered by hydraulic pressure. In the oil supply circuit for the leveling device of the work bucket, a switching valve is interposed in the swing pump oil passage connecting the swing hydraulic pump and the swing operation valve, and one of the outflow side ports of the swing pump oil passage is interposed. A flow divider valve connected to the downstream side of the switching valve in the swing pump oil passage, the other of its outflow side ports being connected to the leveling device, and the inflow side port thereof being connected to the switching valve, and the switching valve is configured to be switchable between a position where the swing pump oil passage is communicated with the swing pump oil passage and a position where the swing pump oil passage is blocked and the front stage of the switching valve in the swing pump oil passage is connected to the inflow side port of the diverter valve. A refueling circuit for a leveling device for a bucket for high-altitude work installed on a mobile crane.