JPH07148810A - Safety door device of molding machine - Google Patents

Abstract

PURPOSE:To obtain a safety door device of a molding machine that can avoid the occurrence of an accident by urging an inspection/repair with the detection of a failure of either an electric safety device or a hydraulic safety device. CONSTITUTION:A pressure sensor 9 detecting a pressure of a pilot oil path 8 of a hydraulic safety device is provided for detecting whether the hydraulic safety device is normally actuated. Using information detected by the pressure sensor 9 and ON/OFF information of a limit switch 2 of an electric safety device turned ON/OFF in accordance with the open/close state of a safety door, the occurrence of an abnormality is judged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a safety door device for a molding machine such as an injection molding machine, a foam molding machine, or a die casting machine, and more particularly, when the safety door is separated from a closed position (when opened). The present invention relates to a safety door device of a molding machine provided with a hydraulic safety device and an electrical safety device for prohibiting the mold clamping cylinder from operating and opening and closing the mold.

[0002]

2. Description of the Related Art A molding machine such as an injection molding machine is provided with a safety door for covering a mold mechanism section, and the safety door is placed in a closed position during a molding operation so as to perform a mold replacement or inspection / check. At the time of repair, the safety door is placed in the open position to expose the mold mechanism. Then, in order to prevent the mold opening / closing operation (the mold clamping cylinder is operated) from being inadvertently performed when the safety door is opened, normally, a hydraulic safety device and an electric safety device are used.
Two safety measures are provided.

That is, as shown in FIGS. 5 and 6, a safety device including a limit switch (safety door limit switch) 2 for detecting whether or not the safety door 1 is in the closed position and a mechanical drive type directional control valve. When the safety door 1 is in the closed position shown in FIG. 5, the limit switch 2 is turned on and the safety door valve 3 is in the first switching position. As shown in FIG. 6, when the valve is slightly moved out of the closed position (even when opened slightly), the limit switch 2 is turned off and the safety door valve 3 is set to the second switching position. When the limit switch 2 is turned off, the mold opening / closing control valve, which is an electromagnetically driven directional control valve for controlling the operation of the mold clamping cylinder, is electrically disabled, and the safety door valve 3 Is in the second switching position, the die opening / closing control valve is hydraulically inoperable.

That is, both the electric safety device including the limit switch 2 and the hydraulic safety device including the safety door valve 3 inhibit the mold opening / closing operation when the safety door 1 is opened. As a result, even if either the electrical safety device or the hydraulic safety device fails, the safety function of the safety door device will work.

[0005]

As described above, if the mold opening / closing operation is prohibited by the electric safety device and the hydraulic safety device when the safety door 1 is opened, the electric safety device or Even if one of the hydraulic safety devices fails, the mold opening / closing operation is prohibited, so that safety is ensured and the occurrence of an accident can be suppressed as much as possible.

However, there is one problem here. In other words, in the conventional safety door device, the safety function of the safety door device behaves as if apparently operating normally, even if either the electrical safety device or the hydraulic safety device is in failure. The machine operator (worker) can determine whether the electric safety device and the hydraulic safety device are both in a normal state, or whether one of the electric safety device and the hydraulic safety device has failed. could not. Therefore, in an extremely rare case, if either the electrical safety device or the hydraulic safety device fails, and the other safety device also fails, the safety function of the safety door device does not work at all, resulting in an accident. It could lead to the occurrence.

Therefore, the technical problem to be solved by the present invention is to solve the problems of the above-mentioned prior art, and the purpose thereof is to provide either an electric safety device or a hydraulic safety device. Detects that the
An object of the present invention is to provide a safety door device for a molding machine that can avoid an accident by urging inspection / repair.

[0008]

In order to achieve the above-mentioned object, the present invention provides a safety door which can be in a closed position for covering a mold mechanism portion of a molding machine and an open position for exposing the mold mechanism portion, A limit switch is turned on when the safety door is in the closed position, and is turned off when the safety door is separated from the closed position, and a driving voltage can be supplied when the limit switch is turned on. The electromagnetically driven directional switching valve (mold opening / closing control valve) that is not supplied with the drive voltage when the limit switch is turned off, and the hydraulic actuator (mold clamping) controlled by the electromagnetically driven directional switching valve. Cylinder) and the safety door is in the closed position, the first switching position in which pressure oil from the hydraulic source cannot be supplied to the pilot oil passage is set, and the hydraulic source is released when the safety door is separated from the closed position. From A mechanical drive type directional control valve (safety door valve) having a second switching position for supplying pressure oil to the pilot oil passage, and the pilot drive oil are connected between the electromagnetic drive type directional control valve and the hydraulic pressure source. In a molding machine equipped with a pilot check valve (for example, a poppet valve) that makes it impossible to supply pressure oil from the hydraulic pressure source to the electromagnetically driven directional control valve when a pressure exceeding a predetermined value rises in the passage,
Pressure detecting means for detecting the pressure in the pilot oil passage is provided, and it is configured to determine whether or not the safety device is operating normally by using at least the information detected by the pressure detecting means.

[0009]

When the safety door is in the closed position, the safety door valve (mechanical drive type directional control valve) takes the first switching position, and the pilot oil between the safety door valve and the control oil chamber of the pilot check valve is used. No pressure builds up in the passage, while the safety door valve takes the second switching position when the safety door opens, and the pilot oil passage has a predetermined enough pressure to close the pilot check valve. The pressure exceeds the value. The pressure detecting means is adapted to recognize the pressure change in the pilot oil passage. Therefore, when the pressure exceeding the predetermined value does not rise in the pilot oil passage when the safety door is opened, the hydraulic system safety device is provided. It can be considered that what kind of abnormality is occurring in. Therefore, by looking at the information indicating whether the safety door is in the closed position and the information from the pressure detection means, it can be determined whether the hydraulic safety device is operating normally.

Further, when the safety door is in the closed position, the limit switch is turned on, for example, and when the safety door is opened, the limit switch is turned off. Therefore, if the limit switch is not turned off when the safety door is opened, it can be considered that an abnormality has occurred in the electrical safety device. Therefore, it is possible to determine whether or not the electrical safety device is operating normally by looking at the information indicating whether or not the safety door is in the closed position and the on / off information of the limit switch.

[0011]

The present invention will be described below with reference to the illustrated embodiments. 1 and 2 relate to an embodiment of the present invention.
FIG. 2 is a diagram showing the configuration of the safety door device when the safety door is in the closed position, and FIG. 2 is a diagram showing the configuration of the safety door device when the safety door is in the open position.

In FIGS. 1 and 2, 2 is the above-mentioned FIGS.
The same limit switch as shown in Fig. 1 and Fig. 2
Although the safety door is not shown in the figure, it is turned on when the safety door is in the closed position and is turned off when the safety door is opened even slightly. Reference numeral 3 is the same safety door valve (mechanical drive type directional switching valve) as shown in FIGS. 5 and 6, and when the safety door is in the closed position, the first switching position shown in FIG. Thus, when the safety door is opened even slightly, it takes the second switching position shown in FIG.

A mold closing cylinder (hydraulic cylinder) 4 serving as a drive source for the mold opening / closing operation and a mold opening / closing control valve 5 composed of an electromagnetically driven directional control valve 4 are controlled.
A pilot check valve 6 composed of a poppet valve is disposed between the die opening / closing control valve 5 and a hydraulic pressure source (not shown), and the pressure oil from the pressure oil supply oil passage 7 is in the state of the pilot check valve 6. Is selectively supplied to the mold opening / closing control valve 5. Pressure oil is supplied to the safety door valve 3 by a branch oil passage 7a from a pressure oil supply oil passage 7, and the safety door valve 3 and the control oil chamber of the pilot check valve 6 are connected by a pilot oil passage 8. ing. Then, when the safety door is in the closed position, the safety door valve 3 takes the first switching position shown in FIG. 1, and the pressure oil from the branch oil passage 7 a is drained and supplied to the pilot oil passage 8. Therefore, the pilot oil passage 8 is not pressurized, so that the pressure oil supply oil passage 7
Via the pilot check valve 6 to the mold opening / closing control valve 5
Is supplied with pressure oil. Further, when the safety door is opened, the safety door valve 3 takes the second switching position shown in FIG. 2, the pressure oil from the branch oil passage 7 a is supplied to the pilot oil passage 8, and the pilot oil passage 8 is A pressure exceeding a predetermined value sufficient to bring the pilot check valve 6 into the closing operation state is raised, and the pressure oil supply from the pressure oil supply oil passage 7 to the mold opening / closing control valve 5 is shut off by the pilot check valve 6.

Reference numeral 9 is a pressure detecting means for detecting the pressure (hydraulic pressure value) in the pilot oil passage 8, and in this embodiment, a pressure switch which switches according to the pressure is used. The pressure switch 9 outputs, for example, an “H” level signal when the pressure exceeding the predetermined value Po sufficient to close the pilot check valve 6 in the pilot oil passage 8 is set, and outputs the predetermined value Po. When the pressure exceeding 0.1 does not stand, an "L" level signal is output. The output of the pressure switch 9 is the abnormality determination circuit 1
It is designed to be sent to 0.

Reference numeral 11 denotes a valve driver for switching and driving the die opening / closing control valve 5. In this embodiment, the limit switch 2 is arranged on a lead wire for supplying an operating voltage to the valve driver 11. . Therefore,
Since the limit switch 2 is turned on as described above when the safety door is in the closed position, the valve driver 11
The mold opening / closing control valve 5 can be driven electromagnetically, and the limit switch 2 is turned off as described above when the safety door is opened.
It is designed so that it can not be driven electromagnetically. The ON / OFF information of the limit switch 2 is also sent to the abnormality judging circuit 10. Here, for example, when the limit switch 2 is ON, an "H" level signal is sent to the abnormality judging circuit 10. When the limit switch 2 is turned off, an “L” level signal is output to the abnormality determination circuit 10.

Reference numeral 12 is a warning means for making an operator (worker) recognize that an abnormality has occurred when the abnormality determination circuit 10 makes an abnormality determination, such as a lamp and an alarm message display means. Things are used.

Next, the operation of this embodiment having the above configuration will be described. When all parts of the safety door device are normal, the limit switch 2 is turned on as shown in FIG. 1 when the safety door is in the closed position, and the safety door valve 8 is the first one shown in FIG. Of the valve driver 1 because there is no pressure in the pilot oil passage 8 at the switching position.
1, the mold opening / closing control valve 5 can be electrically switched, and the pressure oil supply oil passage 7 to the pilot check valve 6
Since pressure oil is supplied to the mold opening / closing control valve 5 through the
The mold clamping cylinder 4 is driven by the mold opening / closing control valve 5,
As a result, the mold opening / closing operation is performed by the mold opening / closing mechanism (not shown).

When all the parts of the safety door device are normal, the limit switch 2 is opened when the safety door is opened.
2 is turned off as shown in FIG. 2, the safety door valve 8 takes the second switching position in FIG. 2, and a pressure exceeding a predetermined value Po rises in the pilot oil passage 8 to cause the valve driver 11 to open and close the mold opening / closing control valve. The electromagnetic switching operation of 5 is disabled (at this time, the mold opening / closing control valve 5 maintains its neutral position by itself), and the pilot check valve 6 also supplies pressure oil from the pressure oil supply oil passage 7 to the mold opening / closing control valve 5. The die opening / closing control valve 5 is hydraulically shut off, and the operation thereof is prohibited.

Here, some abnormality in the hydraulic safety device,
That is, for example, when the safety door is opened, a predetermined value Po is set in the pilot oil passage 8 when the safety door valve 3 is broken, the pilot oil passage 8 is clogged, the pilot oil passage 8 is disconnected from the pipe, or oil leaks. Consider the case where the pressure exceeds the limit.
At this time, since it is practically unlikely that the hydraulic safety device and the electrical safety device will be abnormal at the same time, it is assumed that the limit switch 2 is turned off when the safety door is opened. In such a case, the "L" level signal from the pressure switch 9 and the "L" level signal from the limit switch 2 are input to the abnormality determination circuit 10, respectively. Here, the fact that the “L” level signal is output from the limit switch 2 indicates that the safety door is opened, so at this time, normally, the pressure switch 9 outputs “H”. Since the "L" level signal is being output even though the "level signal should be output," the abnormality determining circuit 10 recognizes that an abnormality has occurred, and causes the warning means 12 to output that fact. .

On the other hand, when an abnormality occurs in the electric safety device, that is, for example, welding between the movable contact and the fixed contact of the limit switch 2 occurs and the limit switch 2 does not turn off when the safety door is opened ( (If left on). Even in this case, it is practically unlikely that the hydraulic safety device and the electrical safety device will become abnormal at the same time. Therefore, when the safety door is opened, the pressure in the pilot oil passage 8 exceeding the predetermined value Po is exceeded. Is standing. In such a case, the "H" level signal from the pressure switch 9 and the "H" level signal from the limit switch 2 are input to the abnormality determination circuit 10, respectively. Here, the fact that the "H" level signal is output from the pressure switch 9 indicates that the safety door is opened. Therefore, at this time, normally, the limit switch 2 outputs "L". Since the "H" level signal is being output even though the "level signal should be output, the abnormality determination circuit 10 recognizes that an abnormality has occurred and causes the warning means 12 to output that fact. .

That is, in the abnormality judging circuit 10 of the present embodiment, the combination of the signals from the limit switch 2 and the pressure switch 9 is regarded as a normal state when one is at "H" level and the other is at "L" level. However, when the combination of the signals from the limit switch 2 and the pressure switch 9 is both “H” level or both “L” level, an abnormality occurs in either the hydraulic safety device or the electrical safety device. It is supposed to be considered. Therefore, even when the safety door device is in the closed position, the abnormality determination circuit 10 can determine whether or not an abnormality has occurred in either the hydraulic safety device or the electrical safety device. In this embodiment, it is not possible to specify which one of the hydraulic safety device and the electrical safety device is abnormal, but it is possible to let the operator know that one of them is abnormal. It is possible to promote repairs and avoid accidents.

Next, another embodiment of the present invention will be described with reference to FIGS.
Will be explained. In the above-described embodiment, it was not possible to specify which of the hydraulic safety device and the electrical safety device had the abnormality, but in the present embodiment, it is possible to determine which one of the abnormality has occurred. Therefore, in this embodiment, as shown in FIG. 3, in addition to the sensing means such as the limit switch 2 and the pressure switch 9, a door opening / closing sensor 13 for detecting whether or not the safety door is in the closed position is provided. The output of the open / close sensor 13 is sent to the abnormality determination circuit 10 'together with the outputs of the limit switch 2 and the pressure switch 9. The door opening / closing sensor 1
Any of switches, optical sensors, etc. can be used as 3, but in the present embodiment, for example, it is turned off when the safety door is in the closed position, and turned on when the safety door is opened even slightly. Structural switches are used.

FIG. 4 shows an abnormality determination processing flow executed in the abnormality determination circuit 10 'of this embodiment. When the door opening / closing sensor 13 is turned on, the abnormality determination circuit 1
0'determines that the safety door is open, and executes the door open determination process shown in FIG. That is, in step ST1, if the output of the pressure switch 9 is "H", the process proceeds to step ST2, and if the output of the pressure switch 9 is "L", the process proceeds to step ST4 and an abnormality occurs in the hydraulic safety device. If the output of the limit switch 2 is "L" in step ST2, step ST2
If the output of the limit switch 2 is "H", the operation proceeds to step ST5 and an abnormality occurs in the electrical safety device. On the other hand, when the door open / close sensor 13 is turned off, the abnormality determination circuit 10 'determines that the safety door is closed, and executes the determination processing when the door is closed as shown in FIG. That is, in step ST6, if the output of the pressure switch 9 is "L", the process proceeds to step ST7, and if the output of the pressure switch 9 is "H", the process proceeds to step ST9 and an abnormality occurs in the hydraulic safety device. Further, in step ST7, the output of the limit switch 2 is "H".
If so, the routine proceeds to step ST8 to make normal, and if the output of the limit switch 2 is "L", the routine proceeds to step ST10 to make an abnormality in the electrical safety device.

Therefore, in the present embodiment, the warning means 12 identifies and outputs which of the hydraulic safety device and the electrical safety device has an abnormality in accordance with the determination result from the abnormality determination circuit 10 '. It becomes possible.

[0025]

As described above, according to the present invention, it is detected that either the hydraulic safety device or the electrical safety device has failed, and the safety function of the entire safety door device does not work at all and is inspected before. / It is possible to encourage repairs,
The safety door device of this type of molding machine, which can prevent the occurrence of an accident as much as possible, has a remarkable effect.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a configuration of a safety door device when a safety door according to an exemplary embodiment of the present invention is in a closed position.

FIG. 2 is an explanatory view showing the configuration of the safety door device when the safety door is in the open position according to the embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a main configuration of a safety door device according to another embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a processing flow executed by the abnormality determination circuit of FIG.

FIG. 5 is an explanatory diagram showing the states of the limit switch and the safety door valve when the safety door is in the closed position.

FIG. 6 is an explanatory diagram showing states of a limit switch and a safety door valve when the safety door is separated from the closed position.

[Explanation of symbols]

 1 Safety Door 2 Limit Switch 3 Safety Door Valve (Mechanically Driven Directional Changeover Valve) 4 Mold Clamping Cylinder 5 Type Open / Close Control Valve (Electromagnetically Operated Directional Changeover Valve) 6 Pilot Check Valve (Poppet Valve) 7 Pressure Oil Supply Oil Path 7a Branch oil passage from pressure oil supply oil passage 8 Pilot oil passage 9 Pressure switch (pressure detection means) 10, 10 'Abnormality judgment circuit 11 Valve driver 12 Warning means 13 Door opening / closing sensor

Claims (1)

[Claims] 1. A safety door that can be in a closed position that covers a mold mechanism section of a molding machine and an open position that exposes the mold mechanism section, and a first switching position when the safety door is in the closed position. And a limit switch that takes a second switching position when the safety door is disengaged from the closed position, and a drive voltage can be supplied when the limit switch is in the first switching position, and the limit voltage is supplied. Switch is second
The electromagnetically driven directional switching valve in which the drive voltage cannot be supplied when the switching door is in the switching position, the hydraulic actuator controlled by the electromagnetically driven directional switching valve, and the safety door in the closed position. Has a first switching position where pressure oil from the hydraulic source cannot be supplied to the pilot oil passage,
A mechanically driven directional switching valve that takes a second switching position for supplying pressure oil from the hydraulic source to the pilot oil passage when the safety door is separated from the closed position; the electromagnetically driven directional switching valve; And a pilot check valve that is not connected to the electromagnetically driven directional switching valve when pressure exceeding a predetermined value rises in the pilot oil passage. In the molding machine described above, pressure detection means for detecting the pressure in the pilot oil passage is provided, and it is determined whether or not the safety device is normally operating by using at least the detection information by the pressure detection means. A safety door device for molding machines.