JPH0361080B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a safe operation device for a press.

(Prior Art) A press machine equipped with a so-called two-handed operation device having two operation buttons ensures safe operation because both hands are restrained.

The prior art of a two-hand operated driving device equipped with two driving buttons was invented in Microfilm No. 54-778.

Fig. 2 shows the above-mentioned invention, in which the two-handed pushbutton switches PB2 and PB3 are pressed to energize the corresponding auxiliary relays CR2 and CR3, and the auxiliary contacts CR2 and CR3 are pressed.
is closed, the pin clutch tripping electromagnet M is energized to operate the press, and the auxiliary relay CR2,
When timers TM2 and TM3 are connected in parallel to each of CR3 and one of the pushbutton switches PB2 and PB3 is held pressed and fixed, the timers TM2 and TM3 are
In a press machine in which the auxiliary relay on the pressing side is deenergized after a certain period of time by the action of a timer on the pressing side of TM3, a limit switch LS is connected in parallel to the pin/clutch tripping electromagnet M.
1. Connect the series circuit of auxiliary relay CR4, operate limit switch LS1 at the end of one press stroke, energize the auxiliary relay CR4, and close the normally closed auxiliary contact.
This is characterized in that cr4 and b are opened to stop the excitation of the pin clutch tripping electromagnet M.

Then, timers TM2 and TM3 are connected in parallel to auxiliary relays CR2 and CR3, respectively, and their contacts tm
2, tm3 is connected in series with each relay CR2, CR3. For example, even if push button switch PB2 is pressed and fixed, the contact tm2 will be opened after a certain period of time due to the action of timer TM2, and the auxiliary relay will be activated.
The energization of CR2 is released, the auxiliary contact cr2 is opened, and even if the other pushbutton switch PB3 is pressed, the pin clutch tripping electromagnet M will not operate.
It cannot be used as a one-handed switch type, and in addition to the above timer, it also requires a limit switch LS1 and an auxiliary relay CR to prevent double-strike.
4 is connected in parallel to pin clutch tripping electromagnet M, and normally closed auxiliary contact CR4 is connected to the circuit of electromagnet M.
Insert b, normally open auxiliary contact cr for self-holding relay CR4 in parallel with limit switch LS1
4.Constructed by connecting a.

That is, at the end of one press stroke, the limit switch LS1 operated by a cam attached to the press crankshaft energizes the auxiliary relay CR4, forming a self-holding circuit that closes the contact cr4.a, and also closes the normally closed auxiliary contact cr4. By opening b, the excitation input to the electromagnet M is shielded, for example, a push button switch.
While PB2 and PB3 are pressed, auxiliary contacts cr2 and cr
Even if both pins 3 are in the closed circuit state, the pin/clutch drawer electromagnet M is inactive, and the press does not operate from this point on.

In other words, even if you keep pressing switches PB2 and PB3, limit switch LS1 will operate and the auxiliary relay will
Since CR4 is energized and the normally closed auxiliary contacts cr4 and b open, the press always stops after one stroke, preventing accidents such as double striking.

However, with the above-mentioned conventional technology, it is possible to ensure safety by preventing one-handed operation of the operation button and double-hitting when the operation button is held down.
Since it does not have a confirmation function to check whether the drive button has actually been pressed down, it is not possible to confirm whether or not the driver actually pressed down the drive button. As such, it lacked reliability.

In the conventional technology, if the press operation is stopped due to a power outage after starting the press, the press operation is restarted immediately after the power is restored. When the press stops while it is running, the operator may try to find the cause of the failure and put his face close to the mold to check the condition of the mold, but in such a case, the power is restored and the press stops. If operation resumes, it will lead to an extremely serious accident.

The above conventional technology also has a double-hit prevention function, but the operating range of the limit switch LS1 is determined by the crank angle of the press, so when one stroke is completed, the operation button is kept pressed. If it is, the press will not operate, but if the above situation occurs immediately after startup, that is, during operation, press operation will resume.

In short, the conventional technology does not have a function to check whether the operation button has actually been pressed down.

In addition, in the conventional technology, for example, if the operation button is off and malfunctions, the timer contact is always open, the auxiliary relay is deenergized, and the pin/clutch tripping electromagnet that performs the press operation does not operate. However, if the operation button is on and there is a malfunction, the timer contacts will remain closed, which eliminates the effect of connecting the timer and is a fatal problem for a safe driving device. .

(Problem to be Solved by the Invention) The problem to be solved by the present invention is to solve the problem in a press machine equipped with two operation buttons that can be operated with both hands.
It goes without saying that the press cannot be operated without two-handed operation, but even if one stroke of the press operation is not completed, if the press operation stops, the next operation will not be possible unless the operation button is turned off. To provide a safe operation device for a press that prevents the press from starting even when an operation button is out of order.

(Means for solving the problem) Means for solving the problem in the present invention are as follows:
A first relay X1 that operates when the first operation button PB1 is operated, a second relay X2 that operates when the second operation button PB2 is operated, and a first normally open contact of the first and second relays X1 and X2. Timer T connected to the parallel circuit, the first and second operation buttons
Auxiliary relay X4 in which the normally closed contacts of PB1 and PB2 are connected in series, restart prevention relay X controlled by a press rotary cam switch that turns off before top dead center
5. The second of the first and second relays X1 and X2
A normally open contact, a contact with the timer T that turns off after a certain period of time after energization, and the auxiliary relay X4.
and the first contact of the restart prevention relay X5.
a clutch brake relay X3 connected in series with a normally open contact, a first normally open contact for self-holding of the clutch brake relay X3 connected in parallel to a contact of the timer T, and a clutch brake relay X
3 normally open contacts are connected in series, and a press clutch brake solenoid valve is connected in parallel to the clutch brake relay X3.

(Function) Clutch brake relay X to operate the press
Since contact t of timer T is connected in series to the circuit that operates 3, the two operation buttons PB1 and PB
If both 2 are not operated within a certain period of time, the timer T will time up and the contact t will be opened, so the clutch brake relay X3 will not turn on and the press will not operate.

Moreover, the first normally open contact X5a of the restart prevention relay X5, which turns off before the top dead center of the press, is connected in series to the circuit of the clutch brake relay X3, so that after one stroke of press operation Even if you keep pressing the two operation buttons PB1 and PB2, the press will not operate continuously.

Furthermore, the circuit of the clutch brake relay X3 has normally closed contacts for the operation buttons PB1 and PB2.
Since the normally closed contact X4a of the auxiliary relay X4, which is connected to the power supply through the series circuit of PB1b and PB2b, is connected in series, if the press operation stops midway, the next operation will not occur unless the operation button is turned off. It is possible to prevent the press from restarting operation, and therefore, even if the power is restored immediately after a power outage accident, the press will not restart operation.

(Embodiment) FIG. 1 is an electrical circuit showing an embodiment of a safe operation device for a press according to the present invention. From the viewpoint of operation, this circuit consists of two operation operations: inching operation and safe one-stroke operation.

Inching operation means that the press can be operated only while the operation button is pressed, and in other words, the press stops when the operation button is released.

In addition, safe one-stroke operation is the same as inching motion from top dead center to near bottom dead center, but it is operated from near bottom dead center to top dead center without stopping on the way, in other words. , Slide refers to a driving operation in which the vehicle rises all at once after passing the bottom dead center and always stops at the top dead center. In other words, when the slide is in the lowered state, the worker may be injured by the mold, but when it is in the raised state, there is no risk of injury, and if the slide is stopped at the bottom dead center, a stuck phenomenon will occur and the operation will become impossible. To avoid this risk, the slide is raised all at once from near bottom dead center to top dead center.

Note that these operating modes are selected by an operation changeover switch SS1 in the circuit.

In Figure 1, PB1 is the first operation button that is turned on by pressing down with one hand;
2 is a second operation button that is turned on by pressing down with the other hand, and each contact PB
1a, PB2a to connect the first and second relays
1 and X2 are connected for operation. T is a timer, and the first and second relays X
The contact X1a of the button that was pressed first is connected to the parallel circuit of the first normally open contacts X1a and X2a of 1 and X2.
or X2a is turned on. The contact t of this timer T is normally closed and becomes open after a certain period of time has elapsed after the start of operation.

In the embodiment, the operating time of timer T is 0.5
It is set to seconds.

X3 is a clutch brake relay for operating the clutch brake solenoid valve SV1 that directly operates the press, and is connected to the first and second relays X3.
1, X2's second normally open contacts X1b, X2b, timer T's contact t, and auxiliary relay X4's normally closed contact X
4a and the first normally open contact X of the restart prevention relay X5
5a are connected in series and connected to the power supply. In addition, a first normally open contact X3a for self-holding of the clutch brake relay X3 is connected in parallel to the contact t of the timer T.

The above-mentioned auxiliary relay
b, PB2b are connected in series and connected to the power supply. And the auxiliary relay X4 is the operation button PB.
1. Press operation will not continue if PB2 is held down, and the next operation will not be possible unless these operation buttons are turned off.

SV1 is a clutch brake solenoid valve, which is the third normally open contact X3 of the clutch brake relay X3.
c is connected in parallel to the clutch brake relay X3. The circuit of this solenoid valve SV1 further includes a second normally open contact X3b of the clutch brake relay X3 and a first rotary cam switch RS.
1 and the contact that turns on when the "safe one-stroke" operation (safe one-stroke operation) of the operation selector switch SS1 is selected.

Safe one-stroke operation is operation in which the slide makes one reciprocation and always stops at top dead center when the operation button is pressed. First rotary cam switch
RS1 is for this operation and is turned on when the press crank angle is between 150 and 330 degrees, and turned off at other angles. Until this first rotary cam switch RS1 is turned on, the press operation will stop when the operation button is released, but by turning it on at 150 degrees, the press operation will continue even if the operation button is released, until the top dead center. The slide is made to rise.

The above-mentioned restart prevention relay
This is a relay that prevents the press from restarting even if it is kept pressed, and the contact that turns on when the operation changeover switch SS1 is selected for "Job" operation, and the normally closed contact X3d of the clutch brake relay X3. and the normally open contact X4b of the auxiliary relay X4 are connected in series to the power source, and a second normally open contact X5b for self-holding is connected in parallel to the series circuit of the contacts X3d and X4b.

Inching operation is a method of operation when matching molds, etc.
The press operates only while the operation button is pressed, and stops when the operation button is released. Therefore, the restart prevention relay X5 is always kept in an operating state.

The operation changeover switch SS1 is used to select between safe one-stroke operation and inching operation to operate the press in either of the operation modes. In the figure, the contact points are represented by diagonally shaded squares. Note that a second rotary cam switch RS2 is connected in parallel to the operation changeover switch SS1. This second rotary cam switch RS2 is turned off when the press crank angle is between 270 and 315 degrees, and turned on at other angles.

Next, the operation of the embodiment will be explained. First, the operation selector SS1 is used to select the ``Yasuichi line'' operation. Initially, the slide of the press is at the top dead center, so the second rotary cam switch RS2 is on, and since the operation buttons PB1 and PB2 are not pressed, the auxiliary relay X4 is on. Therefore, before the operation button is pressed, the auxiliary relay X4 and restart prevention relay X5 are operating. Further, the first normally open contact X5a of the restart prevention relay X5 is closed, the normally closed contact X4a of the auxiliary relay X4 is open, and the second normally open contact X1 of the first and second relays X1 and X2 is closed.
b and X2b are closed, so clutch brake relay X3 does not operate.

When operation buttons PB1 and PB2 are operated almost simultaneously, the first
and the first normally open contact X1 of the second relay X1, X2
a, X2a become a closed circuit, and timer T starts operating. At the same time, the auxiliary relay X4 becomes inoperable, so the normally closed contact X4a of the auxiliary relay
becomes closed, and clutch brake relay X3 operates. This allows the clutch brake solenoid valve SV
When 1 operates, the press operates normally.

On the other hand, since the second rotary cam switch RS2 is turned off at a crank angle of 270°, the restart prevention relay X5, which was self-held by the second normally open contact X5b,
is turned off, and its first normally open contact X5a is opened. Therefore, the clutch brake relay X3 becomes inoperable, and its second normally open contact X3b and third normally open contact
The normally open contact X3c becomes open and the solenoid valve SV1 becomes inoperable. However, the press slide rises due to inertia, moves to top dead center, and then stops.

If you keep pressing the operation buttons PB1 and PB2, the auxiliary relay X4 will not turn on, so even if you keep pressing the operation button, the restart prevention relay X5 will not turn on.
is never turned on. That is, when the press operation stops, the press operation cannot be restarted unless the operation button is pressed again to intentionally restart the press operation.

Therefore, when one stroke of press operation is completed,
Even in other cases, if the press operation is stopped, the next press operation cannot be started unless the operation button is turned off once. This prevents accidents that may occur if the power supply is temporarily interrupted while the press is operating, causing the press to stop, and then when the power is restored, both operation buttons continue to be pressed. You will be able to do so.

Timer T starts operating when either operation button PB1 or PB2 is turned on. After that, if the other operation button is not operated within the set time of 0.5 seconds, the time is up and the contact t is turned off. Therefore, if one of the operation buttons is left pressed, the press will not operate due to the timer contact t being turned off. That is, the press will not operate unless the operation button is operated reliably with both hands. In other words, in the embodiment, the press cannot be operated unless the operation button is operated with both hands.
Further, the press cannot be continuously operated by the auxiliary relay X4 if the operation button is kept pressed.

The above is a driving operation during safe one-stroke driving,
It is almost the same in inching operation.

In FIG. 1, Em1 is an emergency stop button, and by pressing this button, power to all circuits is cut off and the press is brought to an emergency stop. When the press operation is stopped using this emergency stop button Em1, the operator presses the operation button
Even if PB1 and PB2 are kept pressed, the clutch will not turn on unless clutch brake relay X3 is turned off by the action of Em1 and both operation buttons PB1 and PB2 are pressed again to turn off auxiliary relay X4.

Therefore, even if both operation buttons are kept pressed when the emergency stop is canceled, the press will not suddenly resume operation.

Further, in the embodiment, it is possible to detect a failure even when the timer remains off. In other words, if you press and hold one of the operation buttons and then press the other button after the timer setting time has elapsed, and you are able to press the button, it means that the timer is off and is malfunctioning. It means that. In other words, you can find out whether or not the timer is malfunctioning by operating the vehicle with one hand. However, if the timer is off and malfunctioning, if you keep pressing one of the operation buttons for one-handed operation, either the normally closed contact PB1b or PB2b of the operation button will remain closed, so the auxiliary relay X is off and its normally closed contact X4a does not close. Clutch brake relay X3 is therefore inactive and the press is not operated.

(Effects of the Invention) The present invention has two operating buttons, and the press will not operate unless both are operated, so it goes without saying that the press cannot be operated with one hand. Since the normally closed contact of the auxiliary relay is connected in series with the normally closed contact of the clutch brake relay, the press cannot be operated when one stroke of the press operation is completed or in any other case. If the press stops, the next operation cannot be started unless the operation button is turned off. For example, if the press is stopped due to a power outage while the press is in operation, and then the operation button is turned off when the power is restored. In addition to preventing accidents that may occur due to press operation restarting if the button is pressed continuously, this function also ensures worker safety by preventing the press from starting even if the operation button malfunctions. be.

[Brief explanation of drawings]

FIG. 1 is an electrical circuit diagram for operating a press using the present invention, and FIG. 2 is an electrical circuit diagram according to the prior art. PB1...First operation button, PB2...Second operation button, X1...First relay, X2...Second relay, X3...Clutch brake relay,
X4... Auxiliary relay, X5... Restart prevention relay, T... Timer, RS1... First rotary cam switch, RS2... Second rotary cam switch, SS1... Operation selector switch.

Claims (1)

[Claims] 1. The first operation button PB1 operated by the operation of the first operation button PB1.
relay X1, a second relay X2 that operates when the second operation button PB2 is operated, a timer T connected to the parallel circuit of the first normally open contacts of the first and second relays X1 and X2, and the first and an auxiliary relay X4 to which the normally closed contacts of the second operation buttons PB1 and PB2 are connected in series, a restart prevention relay X5 controlled by a press rotary cam switch that turns off before top dead center, and the above-mentioned first and second the second normally open contacts of the relays X1 and X2, the contact of the timer T that turns off after a certain period of time after energization, the normally closed contact of the auxiliary relay X4, and the first normally open contact of the restart prevention relay X5. A first normally open contact for self-holding of the clutch brake relay X3, which is connected in parallel to the contact of the timer T, and a third normally open contact of the clutch brake relay X3. A press clutch brake solenoid valve is connected in series with the clutch brake relay X3, and a press clutch brake solenoid valve is connected in parallel with the clutch brake relay X3.