JPS5844917B2 - One-handed operation restart prevention device for two-handed presses - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for preventing restart operation due to irregular one-handed operation in a two-handed press.

One of the press operation options is inching operation.

This is mainly used for "mold matching" and "adjustment," but depending on the work, it can also be used for normal press work.

In this case, in consideration of safety, two-handed push button operation is often used.

In two-handed operation, the press is operated by pressing two operation buttons at the same time, so there is no risk of putting one hand in the danger zone, making it a safe operation.

Another option for press operation is safe-stroke operation.

In principle, this is done by pressing the button with both hands.If you let go of the button while the slide of the press is descending, the slide will come to a sudden stop just like in inching operation, so there is no risk of putting your hand in the dangerous area, and this is the most commonly used method. It is a safe driving operation.

However, in conventional operation control circuits, the prescribed operation method is intentionally violated, one of the two-handed push buttons is pressed with tape or an ornament, etc., and the other button is pressed by hand. This makes it possible to drive with one hand.

As a result, due to the tediousness of two-handed operation, the user ends up pressing the button with one hand in an irregular manner, causing the other free hand to accidentally fall into a dangerous area such as between the molds, resulting in personal injury.

In order to prevent such a dangerous operation, the present invention provides a restart operation in which, after pressing the push button with both hands once and restarting the operation, both hands must be released from the push button before operation can be started again. The purpose is to provide a preventive device.

An electrical circuit diagram of an embodiment to which the present invention is applied is shown in FIG. 1, in which PBl and PB2 are the left and right push button switches, R81 is a rotary cam limit switch that is turned off between crank angles 00 and 1500, and R82 is is a rotary cam limit switch that is off when the crank angle is between 300° and 330°, X is a press operation command signal relay, and Y is a two-handed push button return confirmation relay, indicating that both push button switches are not pressed.

■ is the excitation coil of the clutch brake solenoid valve, Z is the restart prevention auxiliary relay, X2゜X3 is the operation command signal relay X
The normally open A contacts, X1, and X4 are also normally closed B contacts.

Yl, Y2. Y3 is the normally open A contact of the two-handed push button return confirmation relay Y, Zl and Z2 are the normally open A contacts of the restart prevention auxiliary relay Z, and SL is the operation selection switch, with off, jiggle, and safety switches respectively. Press operation stoppage, inching operation, and safety
Indicates that stroke operation can be selected.

FIG. 2 shows a known prior art operation control circuit, where Y'
is the push button return signal relay, Y'3 is its normally open A contact,
Y'4 is the normally closed B contact.

The two-handed push-button operation of the present invention is no different in appearance compared to the two-handed push-button operation of the known prior art.

During inching operation, while the pushbuttons are pressed together with both hands, the clutch/brake solenoid valve is energized to start the press and continue operation.

On the other hand, in safe stroke operation, the crank angle set by rotary cam R81 is the same as inching operation, and after that angle, the operation continues until the top dead center, but rotary cam R8
2, it is demagnetized and stops at top dead center.

At that time, even if the push button is kept pressed, the restart prevention auxiliary relay Z prevents the engine from stopping at the top dead center.

Further, when both hand push buttons are released, the next two hand push button operation becomes possible.

However, in the conventional operation control circuit, the A and B contacts of the two-handed pushbutton switches PB1 and PH1 are simply arranged in series, and if one pushbutton is held down and the other pushbutton is pushed later, a pushbutton return signal is sent. Relay Y' is demagnetized and operation command signal relay X is energized to start the press.

Therefore, the prior art had a blind spot that allowed irregular one-handed driving.

The present invention aims to eliminate the blind spots of the prior art described above and enable safe driving operation using only two hands.The contents of the present invention will be explained in detail below.

From the illustrated state before press operation in FIG. 1, there are two push button switches FBI on the left and right.

When both PH1 are pressed, the operation command signal relay
is excited, an operation command signal is issued to the clutch brake solenoid valve excitation circuit, and the machine is started and operated.

Simultaneously with the push button operation, the two-handed push button return confirmation relay Y connects the A contacts of the left and right push button switches and the other A contacts PB1-A, P
Since it is self-held through H1-A, while the left and right push button switches PB1 and PH1 are pressed, an operation command signal is issued and the press is operated.

Since the push button return confirmation relay Y is self-held through its A contact Y2 before both push buttons are pressed, the A contact ¥1 remains closed until the A contacts of both push buttons are closed. There is.

The self-holding circuit through the A contact Y2 is canceled because the B contact X1 becomes open when the operation command signal relay X is energized.

If one or both of the left pushbutton switch PB1 and the right pushbutton switch PB2 are opened, the operation command signal relay X and the pushbutton return confirmation relay Y are demagnetized and the operation of the press is stopped.

Here, if either the left push button switch PB1 or the right push button switch PB2 is pressed and the other push button switch is pressed again in order to issue the operation command signal again, the push button return confirmation relay will be activated. Always open A contact
1 is in the open state, so no operation command signal is issued and the press does not start up.

Only when the left and right pushbutton switches PB1 and PH1 are released together, the pushbutton return confirmation relay Y is self-held again through the left and right pushbutton switches fPB1 and PH1, so the operation command signal can be sent and restart operation is possible. becomes.

Therefore, each time the press is to be started up, the left and right push buttons must be released and then the left and right push buttons must be pressed.

Conventional two-handed operation control devices had a structural blind spot in that they enabled press operation with one hand, but the operation control device of the present invention has the above-mentioned structure and operation, so it has an irregularity. The press does not restart even if operated with one hand, making it impossible to operate the press with one hand, and further ensuring the safety of two-handed operation.

Particularly during inching operation and safe stroke operation in press operation, it is normal to not have a safety device interposed between the push button and a dangerous area such as a mold, so it is desirable to operate the press with two-handed push button operation. By using the one-handed operation protection device of the present invention in combination, safety is enhanced, and effects such as prevention of personal injury and improvement of press work productivity can be achieved.

[Brief explanation of the drawing]

FIG. 1 shows an operation control circuit diagram of a two-handed operating device according to an embodiment of the present invention. FIG. 2 is a circuit diagram of a conventional operation control device. FBI, PB2 are left and right push button switches, PB respectively
1-A, PB 2-A is one A contact of the left and right push button switches respectively, X is the operation command signal relay Y is the two-handed push button return confirmation relay, Y' is the push button return signal relay, ■ is the clutch brake solenoid valve. Excitation coil, Z is restart prevention auxiliary relay, R81. R82 has a crank angle (0° to 1500 off)
(3000 to 3300 off) rotary cam limit switches, but their angles may vary slightly depending on the press configuration.

Claims (1)

[Claims] 1 Equipped with a rotary cam switch that controls press operation, an operation selection switch that selects operation, and a two-handed push button switch for press operation, and includes an operation command signal relay circuit, a push button return confirmation relay circuit, and a restart prevention auxiliary relay circuit. In a press operation control device that has an operation control circuit including a clutch brake solenoid valve excitation circuit and performs inching operation and safe stroke operation with two-hand operation, each A contact of a two-hand push button switch with a multi-contact structure is used. is installed between the operation command signal relay circuit and the pushbutton return confirmation relay circuit, and a self-holding operation circuit and a pushbutton return confirmation relay circuit are formed from the plurality of A contacts of the two-handed pushbutton switch and the pushbutton return confirmation relay circuit. A device for preventing restart operation by one-handed operation in a press operating with two hands, characterized in that a combination of the following is performed to confirm the return of a two-handed push button switch at the time of restart.