JPH04202000A - Balance loading device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a balanced cargo handling device using hydraulic pressure as a driving force.

[Conventional technology]

None of the conventional balanced cargo handling devices used hydraulic pressure as the driving force.

[Problem to be solved by the invention]

Furthermore, the hydraulically driven balanced cargo handling device cannot prevent the load from suddenly rising or falling, that is, from flying or falling when the load suddenly changes.

The present invention has been developed in consideration of the above-mentioned problems, and can prevent the load from rising or falling rapidly in the balance mode.
The object of the present invention is to provide a balanced cargo handling device that allows safe work.

[Means to solve the problem]

In order to achieve the above object, the balanced cargo handling device according to the present invention includes a hydraulic actuator for lifting and lowering a load, a hydraulic source for driving the hydraulic actuator, and a manual operation valve for manually operating the hydraulic actuator. , has a balance valve that adjusts the pressure to balance the weight of the load and the force generated by the hydraulic actuator, and a switching valve that switches between the manually operated valve and the balance valve, and can be in equilibrium for a load of any weight. In a balanced cargo handling device that can realize There is.

[For production]

When the hydraulic actuator suddenly operates in the balance mode, the flow rate flowing into and out of the hydraulic actuator at this time increases, and this is detected by the flow rate sensor. A safety valve is actuated in response to a signal from this flow rate sensor, and the flow of oil into and out of the hydraulic actuator is blocked, and the hydraulic actuator is stopped.

〔Example〕

Embodiments of the present invention will be described based on the drawings.

In the figure, 1 is a cylinder that is a hydraulic actuator of a cargo handling device, 2 is a piston thereof, and 3 is a load suspended from the tip of a rod of this piston 2. This cargo handling device is adapted to move up and down by supplying or discharging pressure oil to or from the rod chamber (reduction chamber) 4 of the cylinder 1.

Reference numeral 5 denotes a hydraulic circuit device connected to the rod chamber 4 of the cylinder 1, and this hydraulic circuit 5 includes a hydraulic source 6, a manual operation valve 7 for manually operating the cylinder 1, the weight 1 of the load 3 and the cylinder. A balance valve 8 that adjusts the pressure to balance the force generated by the first safety valve 10, a switching valve 9 that switches between manual operation and balance operation, and first and second safety valves 10 and 11 and the first and second safety valves 10 and 11.
It consists of check valves 12 and 13 and a throttle 14.

The manually operated valve 7 connects the hydraulic source 6 to the rod chamber 4 of the cylinder 1.
a raised position 7a that communicates with and a neutral position 7 that holds this
b, and a lowered position 7c for draining the rod chamber 4. Further, this manually operated valve 7 is connected to the pilot pressure acting part 9a of the switching valve 9, communicates with the hydraulic pressure source 6 at the upper y7 position 7a and lowered position 7C, and drains at the neutral position 7b. There is.

The balance valve 8 is connected to the hydraulic power source 6 in parallel with the manually operated valve 7, and the balance valve 8 has a neutral position 8a where the outlet circuit 15 and the hydraulic power source 6 are cut off, and a neutral position 8a where the outlet circuit 15 is disconnected from the hydraulic power source 6. It has a pressure oil supply position 8b that communicates with the hydraulic pressure source 6, and a drain position 8c that drains the outlet circuit 15, and has a pilot pressure acting part 8d provided at both ends.
It is designed to switch at a pressure of e. Further, it is biased toward the neutral position 8a by springs 8f and 8g.

A throttle 14 is interposed in the outlet circuit 15 of the balance valve 8, and a pilot pressure acting portion 8d on the supply side of the balance valve 8
is connected to the upstream side of the throttle 14, and the pilot pressure acting section 8d on the drain side is connected to the downstream side.

The switching valve 9 is connected to the throttle 14 of the outlet circuit 15 of the balance valve 8.
The first position 9b communicates only the downstream side of the throttle 14, and the second position 9c communicates both sides of the throttle 14, and the pilot pressure acting on the pilot pressure acting part 9a of this 9c, and normally the first position 9 by the spring 9d.
b.

The first and second safety valves 10.11 are arranged in series between the switching valve 9 and the rod chamber 4 of the cylinder 1. The double-chamber full valves 10.11 have the same configuration, and each has a communication position 10a.

11a and blocking positions 10b and llb.

Pilot pressure acting portions 10c, 10d, llc, and lid for switching are provided at each end, and the first
Pilot pressure acting part 10c on the communication side of the safety valve 1o
is connected to the downstream side of the throttle 14, and the pilot pressure acting part 10d on the shutoff side is connected to the upstream side of the throttle 14 via the check valve 12. Further, the pilot pressure acting part 11c on the communication side of the second safety valve 11 is connected to the upstream side of the throttle 14, and the pilot pressure acting part 11d on the blocking side is connected to the downstream side of the throttle 14 via the check valve 13. . Also, both safety valves 1
0.11 is a constant communication position 10a, a spring 10e on the lla side
11ie.

In the above configuration, by setting the manual operation valve 7 to the raised position 7a or the lowered position 7C, pressure oil is supplied to or drained from the rod chamber 4 of the cylinder 1, and the load 3 is raised or lowered. At this time, pressure oil is also applied to the pilot pressure acting portion 9a of the switching valve 9, and the pressure oil is moved to the second position 9C.
Therefore, there is no pressure difference between the top and downstream of the throttle 14,
Therefore, the balance valve 8 is in the neutral position 8a.

When the manually operated valve 7 is set to the neutral position 7b, the balance mode is entered. At this time, the switching valve 9 is in the first position 9b.

When an upward force is applied to the load 3 in this state, the pressure in the rod chamber 4 is reduced by that amount. As a result, balance valve 8
The balance of the pilot pressure acting part 8 on the drain side is lost.
Since e becomes low, the balance valve 8 is biased by the spring 8f and moves to the pressure oil supply position 8b, and the pressure oil flows into the outlet circuit 15.
This pressure oil is supplied to the switching valve 9, both safety valves 10 and 11.
', the load 3 is supplied to the rod chamber 4 of the cylinder 1, and the load 3 is raised by hydraulic pressure following the above-mentioned upward force.

Furthermore, when a downward force is applied to the load 3 in the above state, the pressure within the rod chamber 4 increases by that amount.

As a result, the balance valve 8 is placed in the drain position 8C, and the amount of oil that has increased due to the pressure increase in the rod chamber 4 is drained, and the load 3 descends following the downward force.

In the balance mode, the oil flowing into and out of the rod chamber 4 passes through the throttle 14 of the outlet circuit 15, so by measuring the pressure before and after the throttle 14, the flow rate at this time can be detected.

At this time, when the load 3 rises rapidly, the exit circuit 15
Oil flows rapidly from the upstream side to the downstream side. Therefore, the pressure on the upstream side of the throttle 14 increases, and the differential pressure at this time acts on each pilot pressure acting portion of the first and second safety valves 10.11. This differential pressure causes the first safety valve 10 to move to the cutoff position 10b against the biasing force of the spring 10e.
As a result, the flow of oil to the rod chamber 4 is blocked, and the load 3
The rapid rise in

At this time, the safety valve 10 is operated against the biasing force of the spring 10e, so the biasing force of the spring 10e is transferred to the output circuit 10.
If 5 is set to a force corresponding to the allowable flow rate of the pressure oil flowing,
Safety valve 1 is activated only when the flow exceeds the specified flow rate in output circuit 15.
0 switches to the cutoff position 10b. This state is maintained by the check valve 12.

If there is a sudden drop in the balance mode, the pressure on the downstream side of the throttle 14 increases, contrary to the above case, and the second safety valve 11 moves against the spring 11e to the shutoff position 11b.
Switch to . This state is maintained by the check valve 13.

Each of the above check valves 12.13 is a pilot check valve, and when necessary, for example, when releasing the cutoff position of the above safety valve 10.11, pressure is applied to each pilot circuit to close each safety valve. 10. Release the pressure applied to the pilot pressure acting parts 10d and 11d in 11.

〔Effect of the invention〕

According to the present invention, in the balance mode, sudden lifting and lowering of the load can be prevented and work can be carried out safely.

[Brief explanation of the drawing]

FIG. 1 is a hydraulic circuit diagram showing an embodiment of the present invention. 1 is a cylinder, 3 is a load, 5 is a hydraulic circuit device, 6 is a hydraulic power source, 7 is a manually operated valve, 8 is a balance valve, 9 is a switching valve, 10
．． 11 is a safety valve. Applicant Komatsu Manufacturing Co., Ltd. Representative Patent Attorney Masaaki Yonehara

Claims (1)

[Claims] A hydraulic actuator that raises and lowers a load, a hydraulic source to drive this hydraulic actuator, a manual operation valve to manually operate the hydraulic actuator, and a pressure source to balance the weight of the load and the force generated by the hydraulic actuator. In a balanced cargo handling device that has a balance valve to adjust and a switching valve to switch between a manually operated valve and a balance valve, and can achieve a balanced state for a load of any weight, the flow rate of oil flowing into and out of a hydraulic actuator. What is claimed is: 1. A balanced cargo handling device characterized by being equipped with a flow rate sensor that detects the flow rate, and having a safety valve that shuts off oil flowing into and out of a hydraulic actuator in conjunction with a signal from the flow rate sensor.