JPS5937041B2 - Safety equipment for hydraulically driven work equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention prevents accidents in which a working machine connected to a power agricultural machine and whose elevation and descent are controlled by hydraulic oil rises, falls, or falls against the operator's will when the engine is stopped or when the engine is started. This relates to a safety device to prevent this.

After stopping the engine that drives power agricultural machinery and working equipment, the operator accidentally operated the control lever of the hydraulic control circuit that controls the lifting and lowering of the working equipment, causing the working equipment to suddenly rise or fall, or the engine to start. At this time, the hydraulic control circuit instructed by the control lever is filled with pressure oil, causing a similar accident in which the work equipment rises or falls, causing unexpected harm to nearby workers and also damaging the work equipment. There are things to do.

For this reason, there are examples in which a holding check circuit is installed that prevents the work equipment from moving up or down even if the control lever is operated after the engine has stopped. There were times when I felt unsafe during daily operations because I had no means to do so.

Therefore, the present invention is proposed in order to eliminate such drawbacks in conventional hydraulically driven working machines, and the configuration is such that the pilot part 10 of the holding check valve
This holding check valve is pushed against the return spring 11 by the pressure oil of the oil pump acting on a, thereby opening the pilot passage 9 and the oil passage from this pilot passage 9 to the hydraulic cylinder for lifting and lowering the working machine. When the pressure oil disappears, the holding check valve is returned by the return spring 11 to close the pilot passage 9 and the oil passage. The hold valve is pushed against the pressure of the spring 16 to close the bypass passage 12 of the pilot passage 9, and as the pilot passage 9 is closed, the spring 16 is pressed.
When the bypass passage 12 is energized, a hold valve is formed so that the pressure oil of the hydraulic pump is returned to the tank via the bypass passage 12, and the bypass passage 12 is closed by forced movement of the hold valve. A safety device for a hydraulically driven working machine, which comprises a hold release part so that pressure oil from an oil pump is supplied to the pilot part 10a, and the hold release part is not operated even when the engine is started. As long as the hydraulic cylinder does not operate, it is designed to prevent sudden accidents such as those mentioned above. Control valve 1 as shown
Through holes 3 and 4 are provided in the device main body 2, which is designed to be attached to the
This through hole 3 has one end communicating with the hydraulic pump 5, and the other end communicating with the through hole 6 of the control valve 1.
One end of the through hole 4 communicates with the hydraulic cylinder 1 for raising and lowering the working machine, and the other end communicates with the through hole 6.

A valve hole 8 is provided to communicate between the through holes 3 and 4, and the pilot passage 9 formed in the through hole 3 near the communicating part with the valve hole 8 and the through hole 4 near the communicating part with the valve hole 8 are simultaneously connected. A holding check valve 10 having a pilot valve part 10a and a valve part 10b that can be closed or opened is fitted into the valve hole 8, and this holding check valve 10 has a pilot valve part 10a and a valve part 10b that are connected to the pilot passage. 9 and the through hole 4 are biased by a return spring 11 to form a holding check mechanism.

Further, this device body 2 is provided with a bypass passage 12 that bypasses the passage hole 3, and a valve hole 13 that communicates this bypass passage 12 with the passage hole 3 at the rear of the pilot passage 9 is connected to the hole on the side of the bypass passage 12. Hole portion 13b closer to through hole 3 than portion 13a
A hold valve 15 formed in a large diameter and capable of closing or opening the throat 14 formed in the bypass passage 12 near the communicating portion with the valve hole 13 is inserted into the valve hole 13. It is biased by a spring 16 in the direction of opening the throat 14 and constitutes a hold release part.

During the work, the throat 14 is closed by pulling the hold valve 15 to the left end as shown in FIG. Pilot valve part 1
0a is separated from the pilot passage 9, so that the pressure oil of the hydraulic pump 5 can be supplied to the hydraulic cylinder 1 from the through hole 9 of the control valve 1 through the pilot passage 9. If the spool 17 is moved by the control valve, the hydraulic piston 19 of the hydraulic cylinder γ can be operated.

When the engine stops in this state and the hydraulic pump 5 stops, the back pressure pushing the back of the hold valve 15 from the hole 13b disappears, so the hold valve 15 returns to the right side as shown in Figure 1 by the spring 16. , the port 14 is opened and pressure oil from the hydraulic pump 5 flows into the control valve 1 through the bypass path 12.

As a result, the hydraulic pressure no longer acts on the holding check valve 10, and the holding check valve 10 reaches the left end as shown in the figure by the spring 11, and the pilot passage 9 and the through hole 4 are closed by the valve parts 10a and 10b, respectively. , whereby the through hole 6 of the control valve 1
The passage from to the hydraulic cylinder 7 is closed.

In this state, even if the engine is started, the pressure oil from the hydraulic pump 5 flows through the bypass passage 12, so the holding check valve 10 still does not move, and the passage to the hydraulic cylinder 1 remains closed. become.

Therefore, even after the engine is stopped and after the engine is restarted, the hydraulic piston 19 cannot be operated by the control lever 18, and the hold valve 15
The hydraulic cylinder 7 is activated by the hydraulic pump 5 only by the operation of
It is possible to establish a state of communication.

Next, another embodiment will be described in which the opening/closing operation of the hold valve 15 of the hold release section is linked to the engine turning-on operation and the control lever 18 operation, as shown in FIG. A hold valve 20 having a large diameter valve part 20a and a small diameter valve part 20b is fitted into the valve hole 13,
Further, the spring 21 that always presses one end of the hold valve 20 to the right positions the hold valve 20 so that the small diameter valve portion 20b of the hold valve 20 reaches the bypass passage 12 and the bypass passage 12 communicates from front to back. , if the electromagnetic solenoid S1 provided in this hold valve 20 is energized, the hold valve 20
is moved to the left so that the valve portion 20a closes the bypass passage 12 as shown in FIG.

Then, when the control lever 18 is placed in the uppermost position of the work machine as shown in Figure 2, a lever switch Cs is provided which closes the normally open contact by being pressed by the control lever 18, as shown in Figure 2 C. The main switch Ms for turning on and off the electric circuit of the power agricultural machine and this lever switch Cs are connected to the electromagnetic solenoid S1 via the coil of the relay H.
and the normally open contact R1 of this relay R.
is connected in parallel with the lever switch Cs to make the relay R self-holding.

Therefore, when the engine is stopped, the main switch Ms is open, or even if the main switch Ms is connected, until the control lever 18 is placed in the uppermost position of the work equipment and the relay R is self-holding. Since the lever switch Cs is in the open state, the electromagnetic solenoid S1 is extinguished, and the bypass path 12 is opened as shown in FIG. 2A to release the pressure oil from the hydraulic pump 5.
The holding check valve 10 blocks the through hole 6 that communicates the through hole 6 of the control box 1 and the hydraulic cylinder 7.

Then, turn on the main switch Ms to start the engine, and then move the control lever 18 to the uppermost position of the work equipment. The lever switch Cs will close and the relay R and electromagnetic solenoid S1 will be energized, as shown in Figure 2. The hold valve 20 moves to close the bypass passage 12, and the pressure oil flowing into the through hole 3 pushes the holding check valve 10 to open the through hole 4, and at this time, the relay R closes the normally open contact R1. Since it is held by the main switch M
At j when s is opened, the through hole 4 remains open regardless of the subsequent position of the control lever 18.

Note that the reference numeral Cu in FIG. 2A is a control unit incorporating a relay R and a normally open contact R1 shown in FIG. 2C.

Further, as another embodiment of the hold release section, as shown in FIG. It is connected to the power source E via the switch Ms and the safety switch Ss, and is also equipped with a holding check mechanism that cuts off the supply and discharge of pressure oil to the hydraulic cylinder 7 when the oil pressure disappears, similar to the holding check valve 10 described above. The hydraulic pump 25 is connected to the control valve 24, and the main switch Ms
The hydraulic pump 25 is configured so that it can be driven by operating the safety switch Ss only when the safety switch Ss is turned on. can be supplied to and discharged from the hydraulic cylinder 1.

The safety switch Ss may be operated in a single action, or may be structured to be linked to the operation of the control lever 18 as in the embodiment shown in FIGS.

In the embodiment shown in FIG. 4, the hydraulic pump 5 is always driven by the engine 23, but there is a gap between the control valve 24 equipped with a holding check mechanism and the hydraulic pump 5. For example, a relief pipe 27 equipped with a solenoid valve type relief valve 26 is provided, and this relief valve 26 is normally open, but only when the safety switch Ss connected in series with the main switch Ms and the power source E is turned on. The relief valve 26 is closed so that pressure oil from the hydraulic pump 5 can be supplied to and discharged from the control valve 24.

In addition, in FIGS. 3 and 4, the reference numeral 28 is a starter motor, and the reference numeral 29 is a starter switch.

Further, as another embodiment of the hold release section, the holding is released only when the control lever 30 is moved back to the position when the engine is stopped after the engine is started. As shown in C, the base of the control lever 30 is pivotally connected to the pin shaft 32 attached to the lever scale plate 31, and the base of the operating arm 33 is pivotally connected to the pin shaft 32 to the side of the control lever 30. The actuating arm 33 is rotatable in parallel with the control valve 24, and the actuating arm 33 is connected to the spool of the control valve 24.
4 so that the hydraulic cylinder 7 can be operated.

Then, an electromagnetic solenoid S2 is attached near the rotation end of the actuation arm 33, and a fitting hole 30a is bored in the side surface of the control lever 30 on the actuation arm 33 side.
When the electromagnetic solenoid S2 is energized at the position where the control lever 30 is aligned with the control lever 30, the iron core of the electromagnetic solenoid S2 fits into the fitting hole 30a, and in this state, the operating arm 33 can rotate together with the control lever 30. Do it like this.

Further, the control lever 30 and the operating arm 33 are provided with contacts 30b and 3 that can contact each other at the same distance from the bottle shaft 32.
3a, one terminal of the power source E is connected to the contact 33a via the main switch Ms, as shown in FIG.
If the terminal is connected to the contact 30b via the solenoid S2, the control lever 30 will be moved to the operating arm 3 when the main switch Ms is turned on and the engine is running.
3, a hold release portion is configured that enables the control lever 30 to control the elevation of the working machine.

In other words, when finishing work, stop the engine and turn the main switch M.
Since the electromagnetic solenoid S2 is demagnetized by turning s off, the operating arm 33 will not rotate at all even if the control lever 30 is operated thereafter.

Next, even if the main switch Ms is turned on to restart the engine, unless the control lever 30 is rotated to the position of the operating arm 33, the electromagnetic solenoid S2 remains demagnetized, so the hydraulic cylinder 7 cannot be operated. Thereby, even if the starter switch St is turned on and the starter motor 34 is rotated, there is no possibility that the hydraulic cylinder 7 will operate.

As explained in each of the above embodiments, in this invention, after the engine is stopped, the supply and discharge of pressure oil to the hydraulic cylinder is cut off by the holding check mechanism of the control valve, so that the work equipment maintains its position. After that, even if there is an erroneous operation of the control lever, the work equipment will not move up or down at all, and even after the engine starts, the hydraulic cylinder will not operate unless the hold release part is operated, so the work equipment will not suddenly move when the engine starts. Accidents caused by lifting or falling can also be prevented, and the present invention is highly effective in preventing accidents caused by accidental vertical movement of the working machine when the engine is stopped or started.

[Brief explanation of drawings]

Figure 1 is a vertical sectional view showing the embodiment of the invention shown in Figure 1, Figure 2 A is a vertical sectional view of the second embodiment of the present invention, and Figure 2 C is a vertical sectional view of the second embodiment of the present invention. Circuit diagram of electrical part in 9 ports, 3rd
4 and 4 are schematic circuit diagrams showing the third embodiment and the fourth embodiment, respectively, FIG. , FIG. 5C is a schematic circuit diagram of the same embodiment. Description of symbols, 1, 24...Control valve, 2...Device body, 3, 4.6...Through hole, 5, 25...Hydraulic pump ,7...
Hydraulic cylinder, 8, 13... Valve hole, 9...
...Pilot passage, 14...Throat, 10
・・・・・・Holding check valve, 10a
=Pilot part, 10a, 20a120b...
・Valve part, 11...Return spring, 11, 16.21
... Spring, 12 ... Bypass path, 13
a, 13b...hole, 15.20...
Hold valve, 17... Spool, 18.30.
...Control lever, 19...Hydraulic piston, Sl, S2...Electromagnetic solenoid, C
8... Lever switch, Ms... Main switch, R... Relay, E... Power supply, Cu... Control unit, Ss...・
... Safety switch, St ... Starter switch, 22 ... Clutch, 23 ... Engine, 26 ... Relief valve, 27 ...・・Escape L [, 28 ・・・・ Cell motor, 29 ・・・・・
・Starter switch, 31... Lever scale plate, 32... Bin shaft, 33... Operating arm, 30a... Fitting hole, 30a, 30b.・・・
...Contact, 34...Cell motor.

Claims (1)

[Claims] 1 Holding check valve pilot part IQ
This holding check valve is pushed against the return spring 11 by the pressure oil of the oil pump acting on a, thereby opening the pilot passage 9 and the oil passage from this pilot passage 9 to the hydraulic cylinder for lifting and lowering the working machine. When the pressure oil disappears, the holding check valve is returned by the return spring 11 to close the pilot passage 9 and the oil passage. The hold valve is pushed against the pressure of the spring 16 to close the bypass passage 12 of the pilot passage 9, and as the pilot passage 9 is closed, the spring 16 is pressed.
When the bypass passage 12 is energized, a hold valve is formed so that the pressure oil of the hydraulic pump is returned to the tank via the bypass passage 12, and the bypass passage 12 is closed by forced movement of the hold valve. A safety device for a hydraulically driven working machine, comprising a hold release part so that pressure oil from an oil pump is supplied to the pilot part 10a.