JPS5916124B2 - Hydraulic cylinder expansion/contraction sequence control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an expansion/contraction sequence control device for two hydraulic cylinders.

Conventionally, it is common practice to automatically control the operation of contracting one hydraulic cylinder, then extending or contracting the other hydraulic cylinder, and then, after extending said one hydraulic cylinder, contracting or extending the other hydraulic cylinder. The two three-position directional control valves are automatically controlled by signals issued by limit switches installed at the ends of the telescopic strokes of each hydraulic cylinder, but since the supply of hydraulic pressure is cut off to the non-operating hydraulic cylinder, the hydraulic pressure is Not only does the resistance force against the expansion or contraction load of the cylinder become smaller, but also the number of large valves increases, making it difficult to downsize the valve device unit and making the control device more expensive.

The present invention achieves such sequential operation of hydraulic cylinders with a valve device consisting of one directional control valve, one sequence valve, and a small solenoid valve for switching the vent circuit. .

The figure shows an elevator plate 3 installed in a tailgate 2 that closes the rear end opening of a garbage storage box 1 so as to be able to move up and down along a fixed trajectory so as to always cooperate with the tailgate to form a garbage passage. A hydraulic cylinder 4 for raising and lowering the platform is installed between the platform 3 and the garbage storage box 1, and a hydraulic cylinder 7 for rotating the panel is installed between the platform 3 and a loading panel 60 pivoted to the lower end of the platform by a shaft 5.
This figure shows the case where the present invention is applied to a garbage collection vehicle equipped with.

Both hydraulic cylinders 4 and 7 are connected in parallel to one directional control valve 8, and a high-pressure side oil passage 9 between the directional control valve and one hydraulic cylinder 4 when the hydraulic cylinder is contracted is connected to this. A sequence valve 11 that is supplied with pilot pressure from an oil passage 10 to the other hydraulic cylinder 7 that communicates with the other hydraulic cylinder 7 is inserted, and a spool support spring mounting chamber 12 of the sequence valve is connected to an I for maintaining internal pressure.
A solenoid valve 14 is connected to the tank T via the J IJ valve 13, and is inserted between the spool support spring mounting chamber 12 and the tank T, and is always energized to shut off, and the directional control valve 8 and the tank A check valve 38 is inserted into the return oil passage between the sequence valve-related oil passages 9 and 10 and the oil passage 15 on the opposite side.
, 37 are on the high pressure side, the switches 16, 17 for controlling the opening of the electromagnetic valve 14 from the end of the operation of the other hydraulic cylinder 7 until the end of the operation of the one hydraulic cylinder 4 are connected to the two hydraulic cylinders 4, 37. Attach each to the working end of 7.

The illustrated lifting board 3 has links 1B at the top and bottom on both sides, respectively.
The lower both-side links 19 are arranged on the outside of the tailgate 2, and are connected to the upper and lower front ends of the tailgate 2 via 19, and are connected to the upper and lower front ends of the tailgate 2 through arcuate long holes 20 formed in the side wall plates of the tailgate. A loading panel pivot shaft 5 protruding outwardly through the
The both-side links 19 are connected to the elevator board 3 via the shaft 5, and the hydraulic cylinders 4 for raising and lowering the elevator boards on both sides arranged on the outside of the tailgate 2 are connected to the rear of the shaft 5 and the garbage storage box 1. It is installed between the top and the end.

On the other hand, a hydraulic cylinder 7 for rotating the panel is connected between the lifting board 3 and both side portions of the loading panel 60, respectively.

21 is a horizontal cylindrical garbage collection box 1 with upper and lower rails 22
The garbage extrusion board 21 is mounted so as to be slidable back and forth via a screw 23, and the garbage extrusion board 21 can be slid back and forth by an appropriate hydraulic device.

Therefore, when the tailgate 2 is rotated upward about the tailgate pivot shaft 24 to open the rear end opening of the garbage storage box 1, the built-in garbage can be discharged.

As shown in FIG. 4, the sequence valve 11 includes a spool 25 that is operated by internal pilot pressure on the primary side 9a of the oil passage 9, and when the pilot pressure reaches a set pressure, the pressure is maintained at a constant pressure by the relief valve 13. The spool is pushed up against the internal pressure of the spool support spring mounting chamber 12 and the elasticity of the spool support spring 26, thereby communicating the primary side 9a and the secondary side oil passage 9.

Reference numeral 27 indicates a pressure setting spring for the IJ-F valve 13, and reference numeral 28 indicates an elasticity adjustment screw for the spring 27.

The hydraulic cylinder 7 is equipped with limit switches 29 and 16 (Fig. 3) that close at its extension and line end, respectively, and the hydraulic cylinder 4 is equipped with a limit switch 1 that closes at its extension.
7 and a limit switch 30 that opens during contraction are installed, and the directional control valve 80 solenoids 8a, 8b and the solenoid 14a of the electromagnetic valve 14 are sequentially controlled by an electric circuit incorporating each switch as shown in FIG.

In FIG. 5, a relay 31, a timer 32, and a set side 33 of a keep relay (KCR) are connected to a power source 35 via a pushbutton switch 34, and the keep relay (KCR) is connected to a power source 35 via a push button switch 34.
) can be made conductive by the limit switch 17.

When the relay 31 is conductive, its contacts 31a, 31b, 31c
The set side 33 of the keep relay closes its contact 33a and opens its reset side contact 36a when conductive.

The contact 31a is for self-holding, and the self-holding action is stopped by opening the limit switch 30 after the normally closed timer contact 32a is opened by the timer °32.

The limit switch 16゜29 cooperates with the relay contact 31b, keep relay contacts 33a and 36a to close the solenoid 1.
Controls conduction of 4a.

According to the above configuration, when the hydraulic cylinder 4 is contracted and the hydraulic cylinder 7 is extended in the operation stop state shown by the solid line in FIG. 1, the switch 29 is closed as shown in FIGS. 3 and 5, and the switch 30 is open.

In this state, if you put garbage into the tailgate 20 input port 2a as shown in Figure 1 and press the push button switch 34,
The timer 32, which has a set time slightly longer than the time required for the contraction of the hydraulic cylinder 7, starts operating, and the relay 31
conducts and its self-holding contact 31a and contacts 31b, 3
At the same time as closing 1c, the set side 33 of the keep relay becomes conductive, closing its contact 33a and opening its contact 36a.
The solenoid 8a becomes conductive and switches the directional control valve 8 to the third fixed position.

For this reason, the oil passage 15 and the oil passage 37 to the hydraulic cylinder 4 are connected to the discharge port of the hydraulic pump P, but in this case, since the sequence valve 11 of the return side oil passage 9 of the hydraulic cylinder 4 is closed, The hydraulic cylinder 4 maintains its contracted state, the hydraulic cylinder 7 begins to contract, and the loading panel 6 begins to rotate about the shaft 5 toward the inverted position shown by the chain line in FIG.

When the hydraulic cylinder 7 retracts and closes the limit switch 16 until the loading panel 6 reaches the reversed position, the solenoid 14a of FIG. 5 opens the solenoid valve 14.

When the solenoid valve 14 opens, the hydraulic pressure in the spool support spring mounting chamber 12 of the sequence valve 11 disappears, so the check valve 3
The spool 25 is moved by the spool support spring 2 due to the valve opening pressure of 8.
6, the sequence valve opens and the hydraulic cylinder 4 extends, and the return oil flows back through the sequence valve 11 and returns to the tank T.

When the hydraulic cylinder 4 begins to extend, the limit switch 3
0 closes the lower contact as shown by the dotted line in FIG. 5, so the relay 31 is self-held even after the timer contact 32a opens later.

As the hydraulic cylinder 4 expands, the elevator plate 3 moves through the links 18,
19, and when the loading panel 6 reaches the lowered position shown by the solid line in FIG. close, conducts the reset side 36 of the keep relay in FIG. 5, and closes its contact 36a.
Open the contact 33a side.

Therefore, the solenoid 8b becomes conductive and switches the directional control valve 8 to the right position, but in this case, the hydraulic cylinder 7 is contracted and the limit switch 29 is opened, so the solenoid 14
a becomes non-conductive, and the solenoid valve 14 returns to the cutoff position shown in FIG. 3, returning the sequence valve 11 to the state shown.

Therefore, the oil passage 10 becomes the high pressure side, the hydraulic cylinder 7 begins to extend, and the loading panel 6 is rotated to the raking position shown by the chain line in FIG. The garbage is crushed and scraped into the garbage collection box 1 through the passage.

When the resistance to dust scraping by the loading panel 6 becomes excessive and the working oil pressure reaches the set pressure of the sequence valve 11, the sequence valve opens, the hydraulic cylinder 4 contracts, and the elevator platform 3 moves as shown by the solid line in FIG. Raise it to a raised position close to the condition.

At this time, since the oil pressure corresponding to the set pressure of the sequence valve is also applied to the oil passage 10 to the other hydraulic cylinder 7, the hydraulic cylinder 7 is prevented from contracting due to the resistance of the garbage and the loading panel 6 is prevented from being reversed. It is possible.

If the dust scraping resistance is small, the loading panel 6
When the position shown by the chain line in the figure is reached, the limit switch 29 closes and conducts the solenoid 14a, so the sequence valve 1
1 opens again to retract the lifting cylinder 4 and the loading panel 6
to the raised position shown by the solid line in Figure 1.

When the loading panel 6 reaches the raised position, the limit switch 30 is switched to the upper contact in FIG. 5 to open the self-holding circuit of the relay 31 (at this time, the timer contact 32a
is open), the relay contact 31 a 53 l
b and 31c open to stop the loading operation and the electrical circuit returns to the state shown in FIG.

Although the case of a garbage collection vehicle in which the switching order of the directional control valves 8 is also automatically controlled has been described above, the present invention also includes a case in which the directional control valves are manually switched.

According to the present invention, with a hydraulic circuit equipped with one directional control valve and one sequence valve capable of reverse flow using a small electromagnetic valve, it is possible to sequentially operate two hydraulic cylinders each time the directional control valve is switched from side to side. In addition, there is an effect that the light-actuated hydraulic cylinder can be maintained in the extended or linear state during the operation of the rear-actuated hydraulic cylinder.

In addition, when the directional control valve 8 is switched so that the oil passage 10 is on the high pressure side, if the working pressure of the hydraulic cylinder 1 attempts to increase beyond the high set pressure of the sequence valve 11 due to the load, the sequence valve is immediately turned off. opens to operate the hydraulic cylinder 4, so there is no risk of the hydraulic pressure rising excessively and it is not only safe, but also the hydraulic cylinder When the load on the hydraulic cylinder 7 is small, the solenoid valve 14 opens when the hydraulic cylinder 7 completes its operation and lowers the set pressure of the sequence valve 11 to the opening pressure of the check valve 38. It is no longer necessary to increase the pressure to a high setting pressure, and the driving power of the hydraulic cylinder 4 can be reduced according to the load.

[Brief explanation of the drawing]

1 and 2 are longitudinal sectional side views showing the loading operation progress of the main parts of the garbage collection vehicle equipped with the device of the present invention, FIG. 3 is its hydraulic circuit diagram, and FIG. 4 is a sectional view of the sequence valve. Figure 5 is an electrical circuit diagram. 4.7...Hydraulic cylinder, 8...Direction control valve, 11...Sequence valve, 12...
... Spool support blade installation chamber, 13 ... Relief valve, 14 ... Solenoid valve, 16.17 ...
・Limit switch, P...Hydraulic pump, T・
·····tank.

Claims (1)

[Claims] 1 Each has a large load (two hydraulic cylinders 4, which fluctuate)
Both side oil passages of 7 are connected in parallel to one directional control valve 8,
In the oil passage 9 on one side between the directional control valve and one hydraulic cylinder 40, there is an oil passage 10 on the other hydraulic cylinder side communicating with this oil passage 9.
In a hydraulic circuit in which a sequence valve 11 is inserted, which is supplied with pilot pressure from A solenoid valve 14 that is always energized to shut off is inserted between the support spring mounting chamber 12 and the tank, and when the solenoid valve opens, the sequence valve 11 is activated at a low pilot pressure corresponding to the opening pressure of the check valve 38. A switch 16 is configured to open and is switched on the hydraulic cylinder 7 on the optically activated side at both ends of its stroke.
, 29 is installed and the directional control valve 8 is switched to either the left or right switching position, only the switch at the end of the hydraulic cylinder 7 in the operating direction generates a signal to open the solenoid valve 14. A hydraulic cylinder expansion/contraction sequence control device.