JPS5927648B2 - Press brake control circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a marking line alignment device for a press brake.

For bending work using a press brake, there is a method in which a marking line is marked on the workpiece, the slide is brought close to the workpiece until just before processing, and after aligning with the marking line, the slide is used to perform the bending work. .

In this method, it is necessary to temporarily stop the slide immediately before processing, and there is an invention disclosed in Japanese Utility Model Publication No. 47-26044 that automates this operation. The invention disclosed in Japanese Utility Model Publication No. 47-26044 is that a limit switch for stopping the slide is provided on the press brake body, a stop bar is attached to the slide, and when the slide comes just in front of the workpiece, the stop bar activates the limit switch. By activating the slide, the slide is stopped just in front of the workpiece. However, in this method, the stop bar is completely fixed to the slide, so the height of the slide when the limit switch is activated is always the same, and therefore machining can be done by replacing the mold with one of a different height. or when machining plates of different thicknesses, the gap between the workpiece and the upper mold changes when the slide is stopped for matching the markings, making it difficult to match the markings. Something happened. This invention was made in view of the above points, and it is possible to stop the slide at a point where the gap between the workpiece and the upper mold is always constant even if the thickness of the mold, workpiece, etc. differs. It is an object of the present invention to provide a marking line alignment device for a press brake that can perform the following operations.

According to the present invention, the above object is achieved by not directly operating the limit switch with the stop bar, but by providing an adjustment mechanism between the stop bars that can vary the height.

In this invention, as the above-mentioned adjustment mechanism, a variety of blocks with heights corresponding to the heights (thicknesses) of the molds, workpieces, etc. are prepared, and the mold and workpiece to be used are selected from among them. I select items that correspond to objects, etc., and use a stack of them. For example, when replacing a mold, the corresponding block is also replaced at the same time, so that the gap is always constant during marking. Hereinafter, the present invention will be described in detail based on one embodiment of the accompanying drawings.

In a press brake 10 shown in FIG. 1, a holder 2 holding a lower mold 3 is mounted on a table 1.

Further, an upper die 5 is held on the lower surface of the slide 4.
By stepping on the hood switch 7, the slide 4 is lowered so that the workpiece 6 placed on the lower mold 3 can be processed into a predetermined shape. The front panel 10a of the press brake 10 has holding parts 8a, 8 with holes drilled in the center.
b are attached vertically in line, and the holding parts 8a, 8b
A sliding rod 9 is held through the hole so as to be slidable in the vertical direction.

A block holder attachment member 11a is integrally attached to the sliding rod 9 between the holding portions 8a and 8b. Further, a block holder 11 is integrally attached to the block holder mounting member 11a, and the block holder 11 is adapted to move in the vertical direction in conjunction with the sliding rod 9. The holding part 8b and the block holder mounting member 1
A spring 12 is interposed between the spring 1a and the spring 1a.
The sliding rod 9 and the block holder 11 are constantly pushed upward by the stretching force. A switch operating cylinder 13 having a cam surface 13a on its outer periphery is attached to the lower end of the sliding rod 9.

On the other hand, a limit switch 14 is attached to the front panel 10a, and when the sliding rod 9 is lowered, the cam surface 13a of the switch actuating cylinder 13 is attached to the limit switch 1.
The limit switch 14 contacts the contactor 14a of No. 4.
It is starting to operate. The block holder 11 holds blocks 15-1 to 15-4, which have heights corresponding to the heights of the molds 5, 3, the thickness of the workpiece 6, etc., and are removably stacked on top of each other.

The blocks 15-1 to 15-4 always keep the gap between the upper mold 5 and the workpiece 6 constant during marking line alignment, regardless of the height of the molds 5 and 3 and the thickness of the workpiece 6. It is an adjustment mechanism to maintain the In addition, in the stacked blocks 15, blocks 15-1 to 15-4 are connected to the upper mold 15, the workpiece 6,
It corresponds to the lower mold 3 and holder 2. A mounting lever 16 is fixed to the upper part of the slide 4 so as to straddle the upper end of the front panel 10a, and a stop bar 17 is vertically attached to the tip of the mounting lever 16.
is installed.

The stop bar 17 is mounted above the stacked blocks 15, and as the slide 4 descends, the lower end of the stop bar 17 comes into contact with the upper end of the stacked blocks 15, pushing down the block holder 11. Then, slide the sliding rod 9 downward to release the limit switch 1.
4 is now activated. Here, block 1
The principle of gap adjustment according to No. 5 will be explained.

In FIG. 1, A, a, b, c, t, α and H indicate the following distances, respectively.

In other words, A: The amount of movement when the slide 4 moves from the upper limit position to the marking line alignment position (the amount of movement of the upper die 5 at the marking line alignment position)
is indicated by a dotted line 5a) a: Upper mold 5 from the bottom surface of the slide 4
protrusion amount (height of the upper die 5) b: Height of the lower die 3 c: Height of the lower die holder 2 t: Thickness of the workpiece 6 α: Thickness of the workpiece when stopped at the marking line alignment position Gap H between workpiece 6 and upper mold 5: Distance between the lower surface of slide 4 and the upper surface of table 1 when slide 4 is stopped at the upper limit Defined as above, the gap α is expressed by the following formula. .

To make it constant, A+a+b+c+t should be kept constant.

In other words, the increase/decrease in a+b+c+t can be offset by adjusting the movement amount A. In FIG.
If the amount of movement of the stop bar 17 until it comes into contact with y is the amount of descent of the sliding rod 9 necessary to operate the limit switch 14, then the amount of movement A is as follows.

Here, if y is a constant amount, the movement amount A is the stop bar 17
can be adjusted by the amount of movement x. In other words, the height of the block 15 can be adjusted. a+b+c
If +t increases, the amount of movement A needs to be decreased,
To reduce the amount of movement A, it is sufficient to reduce the amount of movement X, and to make the amount of movement x smaller, it is necessary to increase the height of block 15, so the height of block 15 will eventually increase or decrease in accordance with the increase or decrease in a+b+c+t. This makes it possible to keep the gap α constant. Therefore, in this invention, blocks 15-1 to 15-4 of the same height (A, t, b, c) as the upper mold 5, workpiece 6, lower mold 3, and lower mold holder 2 are prepared, and A set of blocks 15 is constructed by stacking the blocks 15, and the amount of movement X is adjusted to a distance that makes the gap α a predetermined value. In addition, the above method (the heights A, t, b, and c of the upper mold 5, workpiece 6, lower mold 3, and lower mold holder 2 are used as the heights of the blocks 15-1 to 15-4) One more condition is required to adjust the gap α using the above method. That is, the heights of the stopper 17 and the block holder 11 at the upper limit of the slide are set in a predetermined relationship. That is, if d is the distance between the tip of the stop bar 17 and the lower end of the block 15 (lower end of the block 15-4) at the upper limit of the slide.

Therefore, it is sufficient to set the height relationship between the stop bar 17 and the block holder 11 so that the distance d becomes H-α-y. By the way, when replacing the upper die 5, lower die 3, workpiece 6, and lower die holder 2, the blocks 15-1 to 15-4 are also replaced according to their heights, so the blocks 15-1 to 15-4 are It is convenient if the structure is such that it can be easily attached to and detached from the pro holder 11. FIG. 2 shows an example of this, in which the longitudinal groove 11b of the block holder 11 is
, and protrusions 15 are formed on the blocks 15-1 to 15-4.
A is formed so that the convex portion 15a is sandwiched and held in the vertical groove. In this case, if a pair of springs are attached along both sides of the groove 11b, the clamping and holding can be done more reliably. Next, a sequence control system for operating the press brake 10 based on the configuration described above will be described with reference to FIG.

In FIG. 3, the slide top dead center stop limit switch 18 is for stopping the slide 4 at the top dead center.
This is a switch that turns on just before top dead center.

The limit switch 14 for stopping marking line alignment is the limit switch shown in FIG. The hood switch 7 is also the hood switch shown in FIG. 1, and is depressed when the slide 4 is operated. The marking line matching work switch 19 is a switch that is turned on when performing marking line matching work. The pressurization time adjustment timer 20 is a timer for adjusting the pressurization time, and when the time is up, it turns off the contact 20a and turns on the contact 20b. In addition, each contact of the relays 31 to 40 is shown with a (in the case of a normally open contact) and b (in the case of a normally closed contact) attached to their number. Now, if you want to perform marking line matching work, turn on the marking line matching work switch 19 and contact 19a.
119c119e119f on, contact 19b119d
is in the off state. Relay 3 when stepping on food switch T
4 is turned on, the slide lowering relay 39 is turned on, the slide lowering solenoid valve 22 is turned on, and the slide 4 is turned on.
is descending. When the slide 4 descends and the gap between the upper die 5 and the workpiece 6 reaches a predetermined value α, the limit switch 14 for stopping scribing is turned on, and the relay 35 is turned on. When the relay 35 is turned on, the slide lowering relay 39 is turned off, and the slide 4 stops at that spot. At this point, match the markings. At this time, when the hood switch 7 is turned back, the relay 36 is turned on, but the slide 4 remains stopped. Then, when the hood switch 7 is pressed again, the relay 37 is turned on, the slide lowering relay 39 is turned on again, and the slide lowering solenoid valve is turned on.
As the slide 4 is lowered, the pressurization time adjustment timer 20 starts counting. When the pressurization time adjustment timer 20 times up, the contact 20a is turned off, turning off the relay 9, turning off the slide lowering solenoid valve 22, and stopping the slide 4. Further, by turning on the contact 20b, the bending work completion relay 40 is turned on. When the bending work completion relay 40 is turned on, the slide lift relay 38 is turned on, and the relays 35 and 35, which had been turned on until then, are turned on.
36 and 37 are turned off, and the slide raising solenoid valve 21 is turned on to raise the slide 4.
When the slide 4 reaches near the top dead center, the slide top dead center stop limit switch 18 is turned on, the bending work completion relay 40 is turned off, and the slide lift solenoid valve 21 is turned on.
Turn off and stop the slide 4 at top dead center. As described above, the control circuit shown in FIG. 3 operates the slide 4 by turning on the hood switch 18 once, and once the limit switch 14 for stopping marking line alignment is turned on, the slide 4 is temporarily stopped to perform marking line alignment. The slide 4 is then operated again by depressing the hood switch 18 again.

As explained above, according to the present invention, the limit switch 14 for marking line alignment is not actuated directly by the stop bar, and the height is adjusted between them according to the height of the mold, the thickness of the workpiece, etc. Since an adjustable adjustment mechanism is provided, the gap between the upper mold and the workpiece can always be kept constant when aligning the marking lines even if the height of the mold, the thickness of the workpiece, etc. are different. .

Moreover, the adjustment mechanism is simply to stack blocks with a height corresponding to the height (thickness) of the mold, workpiece, etc., so for example, when replacing the upper mold with another one, Since it is only necessary to replace only the block corresponding to the upper mold with one of a height corresponding to the newly installed upper mold, the work can be carried out efficiently.

[Brief explanation of drawings]

FIG. 1a is a partial front view of a press brake showing an embodiment of the present invention, FIG. 1b is a side view of FIG. 1a, and FIG.
FIG. 3 is a detailed diagram of the block and block holder shown in FIG. 1, and FIG. 3 is a circuit diagram showing an example of a control system for controlling the operation of the embodiment of FIG. 1...Table, 2...Lower die holder, 3...Lower die, 4...Slide, 5...
... Upper mold, 6 ... Workpiece, 7 ...
...Hood switch, 8a, 8b...Holding part,
9...Slider, 10...Press brake, 10a...Front panel, 11...
Protock holder 1, 12... Spring, 13...
...Switch operating cylinder, 14...Limit switch, 15...Proc, 16...
・Mounting lever, 18... Limit switch for stopping the slide top dead center, 19... Switch for marking line alignment work, 20... Pressure time adjustment timer, 2
1...Slide upward solenoid valve, 22.
...Slide down solenoid valve, 31~40
······relay.

Claims (1)

[Claims] 1. A start switch that is turned on by the operator when starting the slide, a solenoid valve that is energized by turning on the start switch to operate the slide, and a solenoid valve that is set just before bottom dead center while the slide is descending. a marking line alignment limit switch that turns on when the marking line alignment position is reached to demagnetize the solenoid valve and stop the slide; and a marking line alignment limit switch that turns on to demagnetize the solenoid valve and stop the slide; A restart circuit that re-energizes the solenoid valve and restarts the slide by turning it on again, a top dead center stop limit switch that stops the slide at top dead center, and an operator when the marking line is not aligned. and a marking line alignment non-execution switch which is turned on by the marking line alignment limit switch to disable the operation of the marking line alignment limit switch. 2. A slide lowering solenoid in which the solenoid valve is energized by turning on the starting switch before the operation of the marking line alignment limit switch, and is demagnetized by turning off the starting switch or turning on the marking line alignment limit switch. The valve is energized by opening the starting switch when marking line alignment is not being carried out, and by turning on the marking line alignment limit switch and turning on the starting switch when carrying out marking line alignment. A control circuit for a press brake according to claim 1, further comprising a rising solenoid valve that is demagnetized when a dead center stop limit switch is turned on.