JPS5813122Y2 - Equipment protection device in case of hydraulic circuit abnormality - Google Patents

Description

[Detailed description of the invention] The present invention relates to an equipment protection device that stops the drive source after a predetermined period of time after issuing a warning in the event of an abnormality in the hydraulic circuit in a hydraulic circuit that operates hydraulic equipment such as lift cylinders and wheel cylinders. The purpose is to prevent equipment damage and personal injury.

Traditionally, abnormalities in the hydraulic circuits that operate hydraulic equipment were detected by detecting malfunctions in related equipment or by visual inspection.In recent years, when oil pressure has decreased due to an abnormality in the hydraulic circuit, a warning lamp is turned on. Something like a monitor is used for the 0- that lights up.

There is also a device that issues a warning when the battery capacity, which is the power source for a battery lift, has decreased.

However, there are many safety problems such as the operator overlooking or ignoring this and continuing the work, resulting in damage to the equipment.

In particular, industrial vehicles such as forklifts often work in noisy environments, and operators may be distracted by the moving load and overlook warnings, resulting in not only equipment damage but also serious personal injury. There is a risk of inviting

This invention aims to solve this problem.
In a hydraulic circuit for operating hydraulic equipment, a detection device installed in the hydraulic circuit to detect abnormality in hydraulic pressure, a warning device connected to the detection device to issue a warning by activation of the detection device, and the warning device. and a delay circuit connected to a stop device for the device and the power source, and configured to activate the stop device to stop the drive source when a predetermined period of time has elapsed after the warning is issued by the warning device, To provide a protection device that warns an operator with a lamp or the like when an abnormality occurs in a hydraulic circuit, etc., and reliably stops a drive source after a predetermined period of time has elapsed after the warning, thereby preventing danger due to the warning being overlooked.

The details of the present invention will be explained below with reference to the illustrated embodiments.

FIG. 1 is a diagram showing a hydraulic operation circuit, in which 1 is a hydraulic supply pump, one side faces an oil tank 5 through an oil pipe to supply oil, the other side is connected to a switching valve 2 through an oil pipe, and the switching valve 2 For example, one chamber A and the other chamber B of a hydraulic device 3 such as a hydraulic cylinder
are connected to each other by an oil pipe, and furthermore, one end of the oil pipe leading to the switching valve 2 is made to face the oil tank 5 to discharge the hydraulic oil.

Furthermore, an abnormality warning device 4 is disposed at an appropriate location between the switching valve 2 and the oil tank 5 on this discharge oil pipe.

FIG. 2 is a block diagram showing -fII of the abnormality warning device, in which 6 is a power switch for the abnormality warning device 4, and 41 is a detection device, such as a pressure switch, connected in series with the switch 6. The system detects changes in the flow rate of hydraulic pressure due to abnormalities in the hydraulic circuit and converts the changes into electrical changes to operate the system.

Reference numeral 42 denotes a first warning device, which is connected in series to the oil pressure detection device 41 and is configured to, for example, light up a lamp.

Reference numeral 43 denotes a first delay circuit, which is connected in parallel to the first warning device and uses, for example, a Zener diode, and after a predetermined period of time has elapsed, a second warning device 44 connected in parallel with this circuit sounds, for example, a buzzer. is being done.

Reference numeral 45 designates a second delay circuit that is substantially similar to the first delay circuit and is connected to the second warning device, and after a predetermined time has elapsed, a drive source stop device 46 connected thereto stops the drive source using a magnetic switch or the like. It is configured as follows.

Next, the -ψ angle of the abnormality warning device will be explained with reference to the expanded connection diagram in FIG. 3. 6 is a power switch, and the pressure switch 411 and The lamp 421 constituting the first warning device 42 is connected in series, and the first delay circuit 43 includes a series body of a variable resistor 431 and an electrolytic capacitor 432 connected in parallel to the lamp 421.
A series body of a transistor 434 and a relay 435 are connected in parallel to this series body, and a transistor 434 is branched from between the variable resistor 431 and the electrolytic capacitor 4320.
The second warning device 44 is composed of a normally open contact 442 which is ON-OFF controlled by the relay 435 and a buzzer 441 connected in series. A second delay circuit 45 connected to a circuit branched from between the contact 442 and the buzzer 441 includes a series body of a variable resistor 451 and an electrolytic capacitor 452, and a Chena diode 453 and a resistor branched from between both members 451 and 452. 454 in series.

The stop device is a thyristor 461 and a magnetic switch 4.
62 in series, and a diode 463 connected in parallel to the switch 462.

In the embodiment of the present invention configured as described above, first, when an abnormality occurs in the hydraulic circuit shown in FIG. 1 due to, for example, a clogged filter or a decrease in the amount of oil in the oil tank, the pressure switch 411 shown in FIG. is turned on, the lamp 421 of the first warning device 42 lights up to send a warning to the operator, and the variable resistor 431 is energized to close the electrolytic capacitor 432.
When charged to a predetermined voltage, the Chena diode 433 is activated after a predetermined time, and the transistor 4340 is energized, the relay 435 is activated, the contact 442 is turned ON, and the buzzer 44 is activated.
1 sounds, and when the variable resistor 451 is further energized and the electrolytic capacitor 452 is charged to a predetermined voltage, the Chena diode 453 is activated after a predetermined time and the thyristor 461 is turned on. or in the case of a diesel engine, a magnetic switch 4 interposed in the fuel cut valve.
62 to shut off the ignition or fuel supply and stop the drive source.

Note that the diode 463 functions to prevent back electromotive force.

As described in detail above, according to this invention, when an abnormality of low oil pressure occurs in the hydraulic circuit that operates hydraulic equipment, for example due to leakage of valves and hoses, falling off of hoses, clogging of filters, etc., the abnormality can be corrected. This system forcibly stops the engine, etc. after a predetermined period of time after warning the operator with a lamp or buzzer, etc. This not only prevents damage to hydraulic equipment and personal injury, but also requires transportation to a repair work site. can do this reasonably and safely.

Furthermore, abnormalities can be easily confirmed even in hydraulic equipment used by an unspecified number of operators, allowing work to be carried out with peace of mind.

Furthermore, if this device is installed in an unmanned hydraulic system, it will be effective as a protection device, and if installed near the filter of the hydraulic circuit, it will also indicate when to replace parts in case of clogging, etc., making maintenance easier. becomes.

In addition, although the said Example demonstrated what had the 1st and 2nd warning device, this can be omitted for the 2nd warning device.

The present invention can also be applied to abnormality warning devices for hydraulic brakes and vacuum brakes.

[BRIEF DESCRIPTION OF THE DRAWINGS] The drawings show an embodiment of this invention; FIG. 1 is a diagram showing a hydraulic operation circuit, FIG. 2 is a block diagram showing the main parts of this invention, and FIG. An example of an expanded connection diagram in the figure is shown. 4: Abnormality warning device, 41: Detection device, 42: First warning device, 43, 45: Delay circuit, 44: Second warning device, 46
: Stop device.

Claims (1)

[Scope of utility model registration request] In a hydraulic circuit for operating hydraulic equipment, a detection device installed in the hydraulic circuit to detect abnormality in hydraulic pressure, and a first warning device connected in series with the detection device to issue a warning upon activation of the detection device. a first delay circuit that is connected in parallel with the first warning device and starts operating upon activation of the detection device and emits an output signal after a predetermined period of time has elapsed;
a second warning device that is connected in series with the delay circuit and issues a warning based on the output signal of the first delay circuit; and a second warning device that is connected in parallel with the second warning device and is activated by the output signal of the first delay circuit. a second delay circuit that starts the process and issues an output signal after a predetermined time has elapsed; and a drive source stop that is connected in series with the second delay circuit and is activated by the output signal of the second delay circuit to stop the drive source. An equipment protection device in the event of an abnormality in a hydraulic circuit, characterized in that an abnormality warning device consisting of a device is installed.