JP2570001Y2 - Hydraulic control circuit of injection molding machine - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic control circuit of an injection molding machine having a turning device for turning an injection device at the time of screw replacement and inspection work inside a heating cylinder.

[0002]

2. Description of the Related Art As shown in FIG. 2, an injection molding machine 1 has a heating cylinder 2 having a nozzle 3 attached to a tip thereof for exchanging a screw (not shown) and maintaining the heating cylinder 2.
In some cases, the entire injection device 5 is turned to a position where interference such as collision with the mold clamping device 4 does not occur.

FIG. 2 shows a known example of a swing cylinder 6.
Shows an injection turning device for turning the entire injection device 5 (detailed description is omitted).

[0004] Reference numeral 7 denotes a first switching valve. The first switching valve 7 operates a shift cylinder 8 that moves the injection device 5 forward and backward with respect to the mold clamping device 4. Reference numeral 9 denotes a second switching valve. The second switching valve 9 operates the swing cylinder 6.

The hydraulic drive source 10 is connected to the primary side of the first switching valve 7 by an oil passage 11, and the primary side of the second switching valve 9 and the hydraulic drive source 10 are They are communicated by a branched oil passage 12.

Reference numerals 13 and 14 denote oil passages. The oil passage 13 connects a forward-side oil chamber (not shown) provided in the shift cylinder 8 to a secondary side of the first switching valve 7. Is shift cylinder 8
Is connected to a retreat-side oil chamber (not shown) provided on the second side of the first switching valve 7. Reference numeral 15 denotes a tank.

When the solenoid 16 of the first switching valve 7 is energized, the forward oil chamber of the shift cylinder 8 communicates with the hydraulic drive source 10, and the reverse oil chamber communicates with the tank 15. As a result, the injection device 5 moves forward.

On the other hand, the solenoid 17 of the first switching valve 7
Is excited, the retreat oil chamber of the shift cylinder 8 communicates with the hydraulic drive source 10, and the forward oil chamber communicates with the tank 15, whereby the injection device 5 retreats.

Reference numerals 18 and 19 denote oil passages.
The oil passage 19 connects the forward turning-side oil chamber (not shown) and the secondary side of the second switching valve 9, and the oil passage 19 is connected to the reverse turning-side oil chamber (not shown) provided in the turning cylinder 6. ) Is connected to the secondary side of the second switching valve 9.

When the solenoid 20 of the second switching valve 9 is excited, the forward turning-side oil chamber of the turning cylinder 6 communicates with the hydraulic drive source 10, and the reverse turning-side oil chamber communicates with the tank 15. Thus, the injection device 5 makes a clockwise forward rotation in FIG.

On the other hand, the solenoid 21 of the second switching valve 9
Is excited, the reverse turning-side oil chamber of the turning cylinder 6 communicates with the hydraulic drive source 10, and the forward turning-side oil chamber and the tank 15
The injection device 5 makes a counterclockwise reverse turn in FIG.

That is, the hydraulic drive source 10 is branched and connected independently to the primary side of the first switching valve 7 and the second switching valve 9. Therefore, based on the excitation of one of the solenoids 20 and 21 of the second switching valve 9, the swing cylinder 6
The operation starts immediately without depending on the operation of the shift cylinder 8.

Reference numeral 22 denotes a limit switch, and the limit switch 22 is for electrically detecting the retreat position of the injection device 5. The detection circuit and the like of the limit switch 22 are not shown.

When turning the injection device 5 in the conventional injection molding machine 1 having such a configuration, first, an operator selects and operates a selector switch of a control panel (not shown) to the "forward rotation" side.

At this time, when the injection device 5 has been sufficiently retracted for turning, and the fact is detected by the limit switch 22, the solenoid 20 is excited. As a result, the injection device 5 is immediately turned forward by the operation of the turning cylinder 6.

On the other hand, when the injection device 5 is not detected by the limit switch 22, the injection device 5 is in a position where the injection device 5 has not been retracted sufficiently to make a forward turn. If the injection device 5 is turned forward in this state, the interference may cause problems such as damage to the nozzle 3 and pinching of the worker's clothing.

Therefore, in order to prevent such inconvenience, an interlock is electrically formed by the energizing operation of the limit switch 22. In addition, in order to return the injection device 5 after the forward rotation to the original position, if the selector switch is selected and operated to the "reverse rotation" side, the injection device 5 is reversely rotated as described above.

[0018]

However, as described above, the first switching valve 7 and the second switching valve 9 are provided with a hydraulic drive source.
10 are connected independently of each other, and since the swing cylinder 6 is operated independently of the operation of the shift cylinder 8, if the limit switch 22 malfunctions due to a failure or the like, the above electric Interlock will not work.

In such a case, immediately after the operation of the selector switch, the turning cylinder 6 is started and the injection device 5 is started.
Is turned, and the above-mentioned inconvenience cannot be prevented.

Therefore, the present invention provides a hydraulic control of an injection molding machine for enabling good forward and reverse turning even if the electric interlock system malfunctions due to a failure or the like. The purpose is to provide circuits.

[0021]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a shift cylinder for moving an injection device having a heating cylinder having a nozzle at a tip thereof forward and backward with respect to a mold clamping device, A rotating cylinder for rotating the injection device to a position where the heating cylinder avoids interference with the heating cylinder, wherein the shift cylinder has a retraction oil chamber for retracting the injection device. A first switching valve is provided for selectively communicating with a hydraulic drive source or a tank, and a first switching valve is provided for selectively communicating respective oil chambers on the forward turning side and the reverse turning side of the turning cylinder with the retreating oil chamber or the tank. Two switching valves are provided, and the turning-side oil chamber or the reverse turning-side oil chamber and the retraction oil chamber of the shift cylinder are simultaneously connected to a hydraulic drive source.

[0022]

[Operation] Since the present invention is configured as described above, the turning cylinder can be operated only when the hydraulic drive source is in communication with the retraction oil chamber of the shift cylinder.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to FIG. In FIG. 1, FIG.
The same members are denoted by the same reference numerals, and the description of the members denoted by the same reference numerals is omitted.

In the present invention, instead of directly connecting the hydraulic drive source 10 and the primary side of the second switching valve 9, the first
An oil passage is provided between the secondary side of the switching valve 7 and the primary side of the second switching valve 9.
Connected at 23. That is, the oil passage 14 is branched to form an oil passage 23.

As a result, the turning cylinder 6 becomes operable only when the backward oil chamber of the shift cylinder 8 and the hydraulic drive source 10 are in communication with each other. If the source 10 is not in communication,
The swivel cylinder 6 cannot be operated in any state.

From this, in addition to the conventional electric interlock, an interlock of the hydraulic system can be formed, and the operation of the swing cylinder 6 itself cannot be realized unless the shift cylinder 8 operates backward.

If the solenoid 17 for retreating the shift cylinder 8 and the solenoid 20 for revolving the revolving cylinder 6 in the forward direction are simultaneously excited, the shift cylinder 8 is actually rejected due to friction or other structural reasons. In other words, the operation of the turning cylinder 6 is not enabled after the retreat operation until the retreat operation ends.

For example, when both cylinders 6 and 8 are operated independently, a delay timer (not shown) in which a time longer than the time required for the operation of the swing cylinder 6 is set is provided. The delay timer may be started to generate a start signal for the solenoid 20 at the same time as the time is up.

[0029]

[Effect of the Invention] Since the present invention is configured as described above, the turning cylinder can be operated only when the hydraulic drive source is in communication with the retraction oil chamber of the shift cylinder, and the electric interlock fails. Before the injection molding machine is confirmed to be sufficiently retracted, the injection molding machine will not be rotated excessively. Inconveniences such as collision with any one of the injection molding machines and catching of clothes can be prevented.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a main part of an embodiment of the present invention.

FIG. 2 is a block diagram showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Injection molding machine 2 Heating cylinder 3 Nozzle 4 Mold clamping device 5 Injection device 6 Revolving cylinder 7 First switching valve 8 Shift cylinder 10 Hydraulic drive source 15 Tanks 11, 13, 14, 18, 19 Oil passage

Claims (1)

(57) [Scope of request for utility model registration] A shift cylinder for advancing and retracting an injection device having a heating cylinder having a nozzle attached to a tip thereof with respect to a mold clamping device; and preventing the injection device from interfering with the heating cylinder by the heating cylinder. A reversing oil chamber for reversing the injection device is selectively connected to a hydraulic drive source or a tank in the shift cylinder. And a second switching valve for selectively communicating the respective oil chambers on the forward turning side and the reverse turning side of the turning cylinder with the retreating oil chamber or the tank, and the turning side oil chamber or the reverse turning side is provided. A hydraulic control circuit for an injection molding machine, wherein an oil chamber and a retraction oil chamber of a shift cylinder are simultaneously communicated with a hydraulic drive source.