JPH033523B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to press brakes, and more specifically, when various data necessary for bending a plate-shaped workpiece is input to a control device, the built-in computer calculates and punches the workpiece. The automatic press brake that approaches the final approach distance of the die is equipped with a fluid pressure detector that drives the movable apron and an electrical signal converter that converts the detected fluid pressure into an electrical signal, and the control device described above. The present invention relates to a press brake that is equipped with a safety mechanism that immediately stops pressurizing work when the pressurizing force is excessive compared to the above-mentioned data.

Conventional fluid-pressure driven press brakes have been equipped with a relief valve on the output side of the pump device, but none have been equipped with a safety device for applying extreme pressure to punches, plate-shaped workpieces, dies, etc.

To be more specific, in the press brake according to the present invention, the length of the bending line used to bend the plate-like workpiece is long and short, and the cross-sectional area of the tip radius of the punch and the shoulder radius of the V-groove of the die is small. It's normal.

Therefore, even if the fluid pressure is below the level at which the emergency stop is activated by the relief valve, an accident may occur in which the tip radius of the punch, the shoulder radius of the V-groove of the die, or the plate-shaped workpiece is damaged, resulting in material loss. There was another inconvenience that posed a danger to one of the employees.

The present invention has been made for the purpose of solving the above-mentioned disadvantages of the conventional press brake, and preferred embodiments thereof will be described in detail below based on the drawings.

In Figs. 1 and 2, the press brake 1 has left and right side plates 5, 5 rising from the bottom plate 3 in a C-shape, and the upper front of the left and right side plates 5, 5 (left side in Fig. 2) has both sides. An upper apron 7 that connects the plates is fixed, and a punch 9 is provided at the lower end of the upper apron 7.
is attached.

A lower apron 13 is provided at a lower position corresponding to the upper apron 7 and is moved up and down by a fluid pressure drive device 11, and a die 15 is attached to the upper end of the lower apron 13.

The above-mentioned C-shaped left and right side plates 5, 5 are provided with gap portions 19 so that the work 17 or W needs to be taken out in the bending line direction (longitudinal direction of the press brake 1) after being bent. A back gauge device 21 is also provided for positioning the bending line of the workpiece 17 when the workpiece 17 is inserted.

Shown at the left end of FIG. 1 is a control device 23 containing a built-in computer.

The control panel 25 of the control device 23 is shown in FIG.
For example, a power switch 27, a mode selection switch 29, a function key 31, a feed speed selection switch 33, a process data setting key 35, etc. are provided.

The function keys 31 include a process data setting key 31a for setting parameters necessary to define each process (one operation), a process data display key 31b for displaying the contents of the above data settings, and a process execution order key. Process setting key 31c for setting
An M setting key 31d is provided for setting the auxiliary function parameters (bending line length B, desired bending angle A, etc.) and correction amount of the workpiece W set above.

Furthermore, a work call key 31e for specifying the work number to be operated prior to continuous operation, a position/speed display key 31f for displaying the current position and speed of the L-axis and D-axis, and a PA setting key for setting various parameters on the system. 31g and PU start key 3 to start the puncher and punch out the necessary data onto the paper tape.
1h and self-diagnosis key 3 to display alarm details
1i.

Figure 4 shows the various data input to the control panel that can be expressed graphically.The plate thickness of the workpiece W is T, the shoulder groove width of the die 15 is V, and the shoulder radius of the die 15 is Rd. , Rp for the workpiece W. Although not shown, the bending line length B is also input from the M setting key 31d as important shape data.

General press brake 1 as seen in Figure 4
In this case, the punch 9 and the die 15 approach the workpiece W positioned on the die 15 and placed horizontally, and the lower end of the punch 9 and both shoulders of the groove of the die 15 perform a bending operation. be.

More specifically, since the bending operation is performed at three points: the tip radius Rp of the punch 9 and the shoulder radius Rd of the die 15, the bending operation is performed using the so-called air bending method in which there is no planar rigid body in contact with the lower surface of the work W. This is bending work.

Therefore, the state of engagement between the lower end of the punch 9 and the die 15,
In other words, how close the lower end of the rounded end Rp of the punch 9 should be from the position where it contacts the bottom of the V-groove of the die 15 in order to bend it to the desired bending angle is a geometrical factor. It can be calculated using mathematical calculations.

Fig. 4 shows that in order to bend the workpiece W at an angle of A as described above, the point where the tip of the punch 9 hits the bottom of the V-groove is D (hereinafter referred to as the theoretical approach distance).
This indicates that it is sufficient to approach the distance of .

If the base angle of the V-groove of the die 15 is θ, it is impossible to bend the angle A to be smaller than the angle θ, and the portion adjacent to the rounded end of the punch 9 is
It is clear that contact with the top surface of the bent workpiece W is not allowed, so in this sense, the fourth
The punch 9 is not shown in the figure.

Next, FIG. 5 will be explained.

FIG. 5 shows a control mechanism for controlling the raising and lowering operation of the lower apron 13, in which a lever 39 that can be freely engaged and detached is provided on a locking piece 37 provided at the longitudinal center of the lower apron 13.

This lever 39 is connected to a shaft 4 provided on a part of a movable member 43 that is rotatable via a shaft 41 fixed to a frame (not shown) provided on the back side of the lower apron 13.
It can swing freely around 5.

Further, a lift limit setting valve 47 for the lower apron 13 is attached to the frame (not shown), and its spool 49 is engaged with one end of the lever 39 via a leaf spring 51 fixed to the frame.

The rotating member 43 described above includes a pin 53 and a link 55.
is connected to one end of the feed screw 57 via
The feed screw 57 is attached to a case 59 fixed to the frame.
It is rotatably supported on the shaft.

An internal gear 61 is provided at the other end of the feed screw 57, and a clutch gear 63 is provided that approaches and engages the internal gear 61 on a spline shaft, and then separates and disengages.

A manual handle 65 is attached to the other end of the clutch gear 63, and a shift lever 67 for moving the clutch gear 63 along the aforementioned spline shaft is provided.

Further, a belt 75 is wound between the internal gear 61 attached to the feed screw 57 and a gear 73 attached to the shaft 71 of a detector 69, such as an encoder, provided in a part of the corresponding case 59. be.

Further, the shaft 8 of the clutch 83 is connected to the above-mentioned detector 69 via a gear 77, a belt 79, and a gear 81.
5 are connected to each other, and further, an output shaft 89 of an electric motor 87 attached to the case 59 and a clutch 83 are axially connected.

The electric motor 87 is attached to the other end of the shaft of the electric motor 87 described above.
A tachometer generator 91 for switching the rotational speed of the motor is connected to the motor.

Next, FIG. 6 shows the fluid pressure drive device 11 that drives the lower apron 7 up and down, and the lift limit setting valve 4.
7 shows a part of the fluid pressure piping diagram related to 7, in which a pump device 93 connected to an electric motor, an oil tank 95, and a pressure detector 97 when raising the lower apron 13 and the detected fluid pressure are sent as electrical signals. an electrical signal converter 99 for converting into
A state in which an electrical signal from the controller 23 is being led to the control device 23 is shown.

Since the apparatus according to the embodiment of the present invention is constructed as described above, the punch 9 and the die 15 are moved in the direction toward each other by the fluid pressure driving device 11, and the plate-shaped workpiece W (or 17) is moved. During pressurization and bending, the fluid pressure value is input to the control device 23.

Therefore, the control device 23 uses the previously input bending line length B, the tip radius Rp of the punch 9, and the die 1.
5, the V-shaped shoulder radius Rd, the V-groove angle θ, the tensile strength of the workpiece W, the tensile strength of the punch 9 and the die 15, the safe allowable pressing force calculated from the cylinder area of the fluid pressure drive device 11, and the detected pressure of the fluid pressure described above. If the detected pressure becomes larger than the above, the above-mentioned approach movement is immediately stopped.

In addition to being used as a safety device as described above, the tip radius Rp of the punch 9, the V groove shoulder width V of the die 15,
A calculation formula for calculating the fluid pressure value necessary to obtain the desired bending angle A is also obtained from the shoulder radius Rd of the die 15, the V groove angle θ, the bending line length and tensile strength of the plate-shaped workpiece W, etc. Therefore, it is also possible to utilize the device of the present invention as a means for knowing the final pressurizing force.

Therefore, the present invention eliminates the inconvenience in the past where workers simply rely on their experience and feeling to perform the bending work while monitoring the hydraulic pressure gauge installed on the side of the press brake, resulting in unexpected disasters. I got it.

[Brief explanation of the drawing]

Fig. 1 is a front view of a press brake as an embodiment of the present invention, Fig. 2 is a side view of the same as above, Fig. 3 is a front view of the control panel, and Fig. 4 is a detail of the die, punch, and workpiece when folded. A sectional view, FIG. 5 is an explanatory diagram of the approach distance setting mechanism, and FIG. 6 is a part of the same hydraulic piping diagram. Explanation of symbols representing main parts of the drawings: 1...Press brake, 9...Punch, 11...Fluid pressure drive device, 15...Die, 23...Control device, 27...Locking piece, 47...Ascent limit setting valve, 97 ...Pressure detector, 99...Electrical signal converter.

Claims (1)

[Claims] 1 In a press brake that bends a plate-shaped workpiece by moving one of the upper apron and lower apron toward and away from the other, input various data necessary for the bending process and control and execute the engagement state of the punch and die. A control device is provided, a fluid pressure detector is provided to drive the movable apron, and an electrical signal converter is provided to convert the detected fluid pressure into an electrical signal. A press brake characterized in that the movement of a movable apron is stopped when fluid pressure exceeds a preset and input value.