JPS6411399B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a device for controlling the operation of a movable apron (ram) in a press machine, such as a press brake.

In a press machine such as a press brake, a movable apron (ram) is close to a fixed apron (bed), and the upper and lower molds attached to the movable apron and the fixed apron engage with each other. Processing such as bending of the plate-shaped workpiece that is clamped between the two is performed. In this type of press machine, a safety device such as a light beam type is installed in front of the working position (the position where the upper and lower molds engage), and when this safety device is activated, the movable apron approaches the fixed apron. is interrupted. Therefore, it is effective in ensuring safety. However, when bending a workpiece that has relatively large rising parts on both sides, such as when manufacturing a box, for example,
When the workpiece is positioned at the working position, the rising portion blocks the light beam at the safety device.
There is a problem in that a safety device such as a light beam type is activated before processing of the workpiece is started, and the approaching operation of the movable apron is stopped.

Additionally, in the past, air bending was performed in which the upper and lower molds were held in a slightly engaged state rather than fully engaged, and the plate material was bent at an arbitrary angle. However, there are problems such as that it is difficult to always accurately maintain the engagement positional relationship between the upper and lower molds.

This invention was invented in view of the conventional problems as described above. Embodiments of the present invention will be described in detail below with reference to the drawings.

1 and 2 schematically and functionally show a press machine according to an embodiment of the invention. The press machine 1 has a fixed apron (bed) 5 at the bottom of the frame 3 like a general press machine.
is fixed, and a movable apron (ram) 7 is attached to the upper part so that it can be raised and lowered. The movable apron 7 is moved up and down by the operation of a hydraulic device 9 such as a hydraulic cylinder mounted on the frame 3.

That is, the hydraulic device 9 has a solenoid valve 1
When the first solenoid SOL ₁ in 1 is excited, it receives pressure oil from the hydraulic pump P via the oil passage 13 and moves the movable apron 7 to the fixed apron 5.
It operates to bring it closer to. When the second solenoid SOL ₂ is energized, the hydraulic device 9 receives pressure oil through the oil passage 15 and operates to move the movable apron 7 away from the fixed apron 5. When both solenoids SOL ₁ and SOL ₂ in the solenoid valve 11 are not energized, the hydraulic pump P
It is in a stopped state without receiving pressure oil supply from the tank T or discharging oil to the tank T.

Therefore, by appropriately controlling both solenoids SOL ₁ and SOL ₂ in the solenoid valve 11, the movable apron 7 can be appropriately approached and separated from the fixed apron 5, and the movable apron 7 can be stopped. It is something that can be done.

Note that a lower mold 17 is attached to the fixed apron 5 as shown in FIG. 2, and the movable apron 7
An upper mold 19 corresponding to a lower mold 17 is attached to the holder. Further, a bracket 21 is attached to an appropriate position of the movable apron 7, and this bracket 2
1 is equipped with a first dog 23, a second dog 25, and a third dog 27 so as to be vertically adjustable. That is, the first dog 23, the second dog 25, and the third dog 27 are each slidably supported by a plurality of vertical guide bars 29 attached to the bracket 21, and each of the first dog 23, the second dog 25, and the third dog 27 is supported by a plurality of vertical guide bars 29 attached to the bracket 21. It is suitably screwed into the screw rod 31. Therefore, by appropriately turning each screw rod 31, the positions of the first dog 23, second dog 25, and third dog 27 can be adjusted up and down, respectively. Note that the screw rod 31 or each dog 23, 25, 27 is provided with a suitable fixing device such as a brake device, and if the screw rod 31 or each dog 23, 25, 27 is
5 and 27 are preferably fixed so that they do not easily move up and down.

The first dog 23 moves the frame 3 when the movable apron 7 rises and reaches the highest position.
This turns off (opens) the first sensing device LS ₁ , which is like a limit switch attached to the sensor.

The second dog 25 is connected to the frame 3 when the movable apron 7 is relatively close to the fixed apron 5.
This turns on (closes) the second sensing device LS ₂ attached to the In other words, the upper mold 1 attached to the movable apron 7 is attached to the lower mold 17 attached to the fixed apron 5.
9 are relatively close together and the lower mold 17 and the upper mold 19 are so close that no part of the worker's body, such as a hand, can fit between the lower mold 17 and the upper mold 19 (for example, The second sensing device LS ₂ is turned ON by the second dog 25 when the distance between the lower mold 17 and the upper mold 19 is approximately 8 mm.

The third dog turns the third sensing device LS ₃ attached to the frame 3 ON ( (closed) operating.

The first sensing device LS ₁ is turned off by the first dog 23 when the movable apron 7 is at the highest position.
It is always in the ON state except when it is in the activated state, and when it is in the OFF state, the movable apron 7
Rising operation (separation operation from fixed apron 5)
It acts to stop the Also,
When the second sensing device LS ₂ is turned ON, it automatically temporarily stops the lowering operation of the movable apron 7 (approaching operation toward the fixed apron 5), and forms a kind of stop position. Furthermore, when the third sensing device LS ₃ is turned on, it acts to cause the movable apron 7 to move upward.

Next, a control device for controlling the operation of the movable apron 7 will be described in detail with reference to FIG.

As is clear from FIG. 3, the control device includes a safety circuit (safety device) 33 and the second sensing device LS ₂
a stop circuit 35 for temporarily stopping the movable apron 7, an actuating circuit (actuating device) 37 for causing the approaching operation of the movable apron 7 to be activated again after the movable apron 7 has temporarily stopped its approaching operation, and a separation control circuit having the third sensing device _LS3 . (Leaving control device) 39, a top dead center stop circuit 41 including the first sensing device LS ₁ described above, an approach actuation circuit 43 including the first solenoid SOL ₁ in the solenoid valve 11 described above, and a second solenoid SOL. It consists of a separation actuation circuit 45, etc. in which a number ₂ is arranged.

The safety circuit 33 includes a first push button switch.
PB ₁ and a second pushbutton switch PB ₂ are connected in series, and a relay R ₂ arranged in the stop circuit 35 is connected to the b contact side of each button switch PB ₁ and PB ₂ .
The b contact R ₂ b and the relay R ₆ are connected in series. Furthermore, the b contact R _{2 b of the relay R 2 and the} relay R ₁ are connected in series to the a contact side of each of the pushbutton switches PB ₁ and PB 2 .

The stop circuit 35 is connected in series with the a contact R ₅ a of the relay R ₅ arranged in the top dead center stop circuit 41, the second sensing device LS ₂ and the relay R ₂ , and the second sensing device LS ₂ is connected in parallel with the a contact R ₂ a of the relay R ₂ .

In the operating circuit 37, a foot switch FS is arranged as an operating switch, and a relay _R4 is connected to the b contact of the foot switch FS, and a relay _R3 is connected to the a contact of the foot switch FS.

The separation control circuit 39 includes a third push button switch.
PB ₃ and relay R ₇ are connected in series, and the third pushbutton switch PB ₃ includes the a contact R ₅ a of relay R ₅ in the top dead center stop circuit 41 and the aforementioned third sensing device LS _3. A circuit in which these are connected in series is connected in parallel. Furthermore, the third sensing device LS ₃ includes a relay R ₇
The a contacts R ₇ a are connected in parallel.

The top dead center stop circuit 41 includes the above-mentioned first sensing device.
LS ₁ and relay R ₅ are connected in series.

In the approach actuation circuit 43, the a contact R ₁ a of the relay R ₁ and the first solenoid SOL ₁ are connected in series, and the a contact R ₁ a is connected to the b contact R ₇ b of the relay R ₇ .
, the a contact of relay R ₂ R ₂ a, and the a contact of relay R ₃
A circuit in which R ₃ a and the b contact R ₄ b of the relay R ₄ are connected in series is connected in parallel.

The separation operation circuit 45 includes a b contact R ₂ b of relay R ₂
, the a contact of relay R ₄ R ₄ a, and the b contact of relay R ₁
R ₁ b, the a contact R ₅ a of the relay R ₅ , and the second solenoid SOL ₂ are connected in series, and the b contact R ₂ b, the a contact R ₄ a, and the b contact R ₁ b are connected in series. The a contact R ₆ a of R ₆ is connected in parallel. In addition, the a contact R ₆ a of the relay R ₆ is connected to the a contact R ₇ a of the relay R ₇ , the a contact R ₂ a of the relay R ₂ , the b contact R 3 b of the relay R ₃ , and the a contact R ₃ b of the relay R ₄ . A circuit in which the a contact R ₄ a is connected in series is connected in parallel.

In the above configuration, when the movable apron 7 is in the highest position and the first sensing device LS ₁ is activated by the first dog 23 and is in the OFF state, the first and second pushbutton switches in the safety circuit 33 are activated.
When a worker presses PB ₁ and PB ₂ with both hands, relay R ₁ is energized. Therefore, the B contact R ₁ b of relay R ₁ operates OFF, the A contact R ₁ a operates ON, and
Solenoid valve 11 in approach actuation circuit 43
The first solenoid SOL ₁ of is energized. for,
The movable apron 7 starts its descending operation (approaching operation with respect to the fixed apron 5) from the highest position. When the movable apron 7 starts descending, the first dog 23 separates from the first sensing device LS ₁ .
LS ₁ turns ON and relay R ₅ is energized. When relay _R5 is energized, its a contact _R5a is turned on. Note that, as mentioned above, after the movable apron 7 starts descending, the operator presses the double pushbutton switch.
When you let go of one or both of PB ₁ and PB ₂ ,
Since the relay R ₁ is de-energized, the first solenoid SOL ₁ in the solenoid valve 11 is deenergized and the second solenoid SOL ₂ is energized. Therefore, the movable apron 7 moves upward (moves away from the fixed apron 5). Therefore, it is possible to prevent an accident such as an operator putting his or her hand between the lower mold 17 attached to the fixed apron 5 and the upper mold 19 attached to the movable apron 7 and crushing them.

As mentioned above, when the movable apron 7 starts to descend and is relatively close to the fixed apron 5 (so close that you cannot put your hand between the lower mold 17 and the upper mold 19), , the second sensing device LS ₂ in the stop circuit 35 is activated by the second dog 25.
Since it is activated, relay _R2 is energized. Therefore, the a contact R ₂ a of the relay R ₂ turns on and enters the self-holding state, and the b contact R ₂ b of the relay R ₂ turns on.
OFF operates. Therefore, both relays R ₁ and R ₆ are maintained in a demagnetized state, and the first solenoid SOL ₁ and the second solenoid SOL ₂ are brought into a demagnetized state, and the lowering of the movable apron 7 is automatically stopped. That is, when the second sensing device LS ₂ is activated, the movable apron 7 automatically stops at a fixed position without rising or falling. Note that after the second sensing device LS ₂ is activated by the second dog 25, the first and second pushbutton switches PB ₁ and PB ₂ are activated.
The temporary stop of the movable apron 7 is maintained even when the ON or OFF operation is performed.

As mentioned above, when the second sensing device LS ₂ is activated and the lowering of the movable apron 7 is temporarily stopped, the workpiece is accurately positioned between the lower mold 17 and the upper mold 19, and the workpiece is While holding it with both hands, press the foot pedal FS and press Relay R _3.
When energized, the first solenoid SOL ₁ of the solenoid valve 11 is energized again, so the movable apron 7 further descends from the temporarily stopped position, engages the lower die 17 and the upper die 19, and processes the workpiece. will be carried out. In addition, the foot switch
When the FS is released, the movable apron 7 stops descending and is held at that position.

As mentioned above, the movable apron 7 descends from the temporary stop position to process the workpiece, and reaches the lowest position where the engagement positional relationship between the upper and lower molds 17, 19 is adjusted in advance. According to
When the third dog 27 turns on the third sensing device LS ₃ , the relay R ₇ is energized and enters a self-holding state.
Therefore, the first
Solenoid SOL ₁ is demagnetized and the first solenoid
Both SOL ₁ and second solenoid SOL ₂ are demagnetized. Therefore, the movable apron 7 will stop at the lowest position. When the foot switch FS is released after the movable apron 7 has been lowered to its lowest position, the relay R ₃ is demagnetized, the relay R ₄ is energized, and the second solenoid SOL ₂ is energized.
The movable apron 7 will rise, and the first dog 23 will move the movable apron 7 to its highest position.
When the sensing device LS ₁ is turned off, the relay R ₅ is demagnetized. By demagnetizing relay R ₅ , the self-holding of relays R ₂ and R ₇ is released, and
First and second solenoids of solenoid valve 11
Both SOL ₁ and SOL ₂ are in the demagnetized state, and the movable apron 7 stops at the raised position, returning to the initial state (note that when the movable apron 7 descends to the lowest position, the third sensing device LS ₃ is turned on). It is also possible to automatically raise the movable apron 7 at the same time as the actuation, regardless of the excitation state of the relay _R3 ).

By the way, as mentioned above, the second sensing device LS ₂
When the movable apron 7 is in a state where the lowering of the movable apron 7 is automatically temporarily stopped due to the ON operation, and the movable apron 7 is raised to return to the initial state, with the foot switch FS released, By turning on the third pushbutton switch _PB3 and energizing the relay _R7 , the initial state is restored as described above.

In FIG. 4, a light sensing device PS, which is a non-contact type switch, is used in the safety circuit 33, and a two-stage foot switch FS is used in the operating circuit 37. The light sensing device PS includes, for example, a light projector and a light receiver,
Normally, it is in the ON (closed) operating state, but when the light beam is interrupted by a part of the operator's hand or the like entering between the lower die 17 and the upper die 19, etc.
OFF (open) operation. When the foot switch FS is depressed in the first step, the contact FS ₁ is closed, and in the second step when the foot switch is depressed further,
Contacts FS ₁ and FS ₂ are both operated to close,
When the pedal is released, both contacts FS ₁ and FS ₂ are in an open state. Note that the other configurations are substantially similar to the embodiment illustrated in FIG. 3, so detailed explanation thereof will be omitted.

In the case of the _embodiment shown in FIG.
When the contact FS ₁ is closed by stepping only one step, the relay R ₃ is energized and the first solenoid valve 11 is activated.
The solenoid SOL ₁ is energized and the movable apron 7 begins to descend. When the movable apron 7 starts descending, the first sensing device LS ₁ is operated to close, and the relay R ₅ is activated.
becomes an excited state.

As described above, when the movable apron 7 is lowered and the second sensing device LS ₂ is closed, the relay R ₂ is energized and enters the self-holding state. Therefore, even if contact FS ₁ of foot switch FS is in the closed operation state,
The first solenoid SOL ₁ of the solenoid valve 11 is deenergized, and the movable apron 7 is automatically temporarily stopped at a position relatively close to the fixed apron 5. As mentioned above, before the movable apron 7 starts descending and the second sensing device LS ₂ is closed, a hand or the like gets inserted between the lower mold 17 and the upper mold 19, causing the light sensing device PS to close. When the beam is blocked, the relay
Since R ₁ is demagnetized from the energized state, the first solenoid SOL ₁ of the solenoid valve 11 is demagnetized,
Since the second solenoid SOL ₂ is excited, the movable apron 7 will rise, ensuring safety.

As mentioned above, after the second sensing device LS ₂ is closed and the lowering of the movable apron 7 is temporarily stopped, even if the light beam of the light sensing device PS is blocked, the relay is activated.
Since R ₁ is kept in an excited state, at this time,
Accurately position the workpiece. In addition, lower mold 1
There is a gap between the mold 7 and the upper mold 19 to the extent that hands cannot be inserted, so it is safe.

As mentioned above, after accurately positioning the workpiece, when the foot switch FS is depressed to the second stage and both contacts FS ₁ and FS ₂ are closed, relay R ₄ is activated.
is excited, so the first solenoid valve 11
Solenoid SOL ₁ is re-energized. Therefore,
The movable apron 7 is further lowered from the temporary stop position to process the workpiece.

When the movable apron 7 is lowered to its lowest position, the third sensing device LS ₃
When closed, relay _R7 is energized, so
The first solenoid in the solenoid valve 11
SOL ₁ is deenergized and the second solenoid SOL ₂ is energized. Therefore, the movable apron 7 is automatically raised. Note that when the movable apron 7 rises to the highest level and the first sensing device LS ₁ is opened, the relay R ₅ is demagnetized, so the self-holding of the relays R ₂ and R ₇ is released and the initial state is restored. It is something.

As can be understood from the above description of the embodiments, the gist of the present invention is as described in the claims.According to the present invention, the movable apron is relatively close to the fixed apron. If the safety device detects danger between them, the movable apron separates from the fixed apron, and the movable apron separates from the fixed apron to the extent that no part of the body, such as a hand, can fit between the molds attached to the movable apron and the fixed apron. When the apron is relatively close to the fixed apron, the movable apron is automatically paused, and after the movable apron is automatically paused, the safety device is in a state in which it has detected a danger. Also, the movable apron is held at a temporary stop without moving away. Therefore, the movable apron can be held relatively close to the fixed apron to accurately position the workpiece, and the workpiece can then be processed. Therefore, even if the shape of the workpiece is such that the safety device detects danger and is activated before machining the workpiece, it can be processed safely.

Particularly, the separation control circuit according to the present invention includes a sensing device that senses the closest approach of the movable apron to the fixed apron, and a dog that operates the sensing device, and the position at which the dog activates the sensing device is adjustable. Because it is a fixed apron and a movable apron, the closest position of the upper and lower molds attached to the movable apron can be adjusted.

Therefore, when bending a plate material by air bending, for example, the engagement positional relationship between the upper and lower molds can be adjusted and always held accurately, and multiple plates can be air bent under the same conditions. When bending by bending is repeated, accurate bending can always be performed. Furthermore, after the approaching operation of the movable apron is stopped due to the activation of the sensing device, the stopped state can be maintained until it is activated by the activation circuit, so that it is stopped until the flow of the mold structure in the plate material has stabilized to some extent. By holding the movable apron in this state, the amount of spring back can be reduced compared to the case where the movable apron is instantaneously moved away, and the bending accuracy by air bending can be further improved.

It should be noted that the present invention is not limited to the above-described embodiments, but can be implemented in separate embodiments by making appropriate changes. For example, it can be easily applied to a type of press machine in which the movable apron is on the lower side and the fixed apron is on the upper side.

[Brief explanation of drawings]

The drawings show embodiments of the invention,
FIGS. 1 and 2 are a front view and a side view functionally showing the press machine.
FIG. 3 and FIG. 4 are explanatory diagrams of a control circuit for controlling the operation of the movable apron, and each shows a different embodiment. Explanation of the symbols representing the main parts of the drawing, 7...
Movable apron, 33...safety circuit, 5...fixed apron, 37...operation circuit, 35...stop circuit.

Claims (1)

[Scope of Claims] 1. A device for controlling the operation of a movable apron in a press machine, which controls the operation of a movable apron 7 before the movable apron 7 approaches the fixed apron 5 while the movable apron 7 approaches the fixed apron 5 in the press machine. a safety circuit 33 for interrupting the approaching operation of the movable apron 7 when activated;
A stop circuit 35 for automatically once stopping the approaching operation of the movable apron 7 when the movable apron 7 comes relatively close to the fixed apron 5.
and an operating circuit 37 that operates to bring the movable apron 7 closer to the fixed apron 5 again after the movable apron 7 once stops, and also operates to return the movable apron 7 to the fixed apron 5. a separation control circuit 3 that operates to stop the approach operation of the movable apron 7;
9, and the separation control circuit 39 includes:
It is equipped with a sensing device LS ₃ that senses the closest approach of the movable apron 7 to the fixed apron 5 and a dog 27 that operates the sensing device LS ₃ , and the position at which the dog 27 activates the sensing device LS ₃ is freely adjustable. An operation control device for a movable apron in a press machine, characterized in that: 2. The operation control device for a movable apron in a press machine according to claim 1, wherein the safety circuit 33 includes a contact type switch. 3. The operation control device for a movable apron in a press machine according to claim 1, wherein the safety circuit 33 includes a non-contact switch.