JPS59176615A - Angle detector for press work - Google Patents

Abstract

PURPOSE:To detect various angles of a work without detaching the work from a receiving nor pressure table by moving photoelectric sensors where a light image of the work is formed in a plane parallel to a lens surface. CONSTITUTION:Position coordinates of plural points on reference coordinates of the work are determined from detection outputs of two line photoelectric sensors 170 on which the light image of the work is formed, and the angle of the work is calculated from the angle of intersection of straight lines connecting the coordinate points to detect the angle of the work without detaching the work from the receiving nor pressure table. Those sensors 170 are moved in parallel in the plane parallel to the surface of a lens for forming the light image of the work and not fixed, so various angles of the work are detected over a wide range.

Description

[Detailed Description of the Invention] The present invention optically projects the end face of the V-shaped bent portion of the target workpiece, and installs a photoelectric sensor for photoelectric detection on the image plane to detect the target workpiece. The present invention relates to an angle detection device for press work that measures a press angle.

The press brake receiver is used when a workpiece 4 made of a metal plate is placed on a mold on a table 2, and the workpiece 4 is pressed by a pressure table 6 to set the angle of the workpiece 4 as shown in FIG. The angle of the workpiece 4 changes slightly depending on the pressure of the pressure table 6. In a press brake, the workpiece 4 is 1 degree and the weight is 2
If you remove it, you will not be able to press it again. Further, the angle of the workpiece 4 located between the support table 2 and the pressure table 6 cannot be measured with a measuring tool because the tables 2 and 6 get in the way. Therefore, conventionally, after the workpiece 4 is pressed, it is removed from the tables 2 and 6, and the press angle of the workpiece is measured using a separately provided measuring tool, and when the angle is larger than a predetermined value, Readjust to increase the pressure on the workpiece 4. In this case, a large number of defective products will be produced before the workpiece 4 is set at a predetermined angle. SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an angle detection device that can detect the angle of the press work without removing it from between the press table and the support table.

The configuration of the present invention will be described in detail below based on embodiments shown in the accompanying drawings.

In FIGS. 2 to 4, reference numeral 10 denotes a base, on which a mounting plate 12 is erected.

An arm is fixed to the base 10, and a lighting fixture 1 is attached to the arm.
4 is attached so that the angle can be adjusted. The mounting plate 12
A tubular holder 16 is fixed to the holder 16, and a cylinder 18 is rotatably fitted into the holder 16. The cylindrical body 18 is fixed to the holder 16 with screws. An internal cylinder 20 is slidably fitted into the cylinder 18, and a casing 22 is fixed to the front end of the cylinder 20. Casing 22
A guide 24 is fitted and fixed in the opening of the guide 24.
A threaded portion formed on the outer diameter of the holder that holds the lens 26 is screwed into a threaded portion formed on the inner diameter of the holder.

28 is a screw fixed to the guide 24, on which a bevel gear 30 is rotatably supported, a filter holder 32 is fixed to the bevel gear 30, and the colored filter 3 is fixed to this screw.
4.36 is installed vertically. Filter 34 is colored green, and filter 36 is colored red. A shaft 38 is rotatably supported by the mounting plate 12, and a rope pulley 40 is fixed to one end of the shaft, and a pipe 42 is fixed to the other end. Reference numeral 44 denotes a cylindrical body that is slidably fitted onto the inner circumferential surface of the pipe 42. One end of a shaft 46 is fixed to this cylindrical body, and the other end of the shaft 46 is rotatably supported by the casing 22. A long groove is formed in the pipe 42 along its longitudinal direction, and the cylindrical body 44 is inserted into the long groove.
The pins fixed to are arranged so that they can slide freely. An intermediate portion of the shaft body 46 is rotatably supported by a bracket 48 fixed to the casing 22. The shaft body 46
A bevel gear 50 is fixed to the bevel gear 50, and the bevel gear 50 meshes with the bevel gear 30. 52 is a pulse motor fixed to the mounting plate 12, and an endless rope is passed between the rope pulley fixed to the output shaft of this pulse motor and the rope pulley 40. 54 is a holder fixed to the internal cylinder 20, and a heat insulating filter 56 is fixed to this. 58 is a tube rotatably supported on the mounting plate 12, on which a shaft 60 is rotatably arranged, a lever 62 is fixed to one end of the shaft 60, and a member 64 is fixed to the other end. Fixed. A screen 66 made of a glass plate for checking focus is fixed to the member 64. A lever 67 is fixed to one end of the tubular body 58, and a glass screen 68 for checking focus is fixed to the other end via a member. Reference numerals 70 and 72 designate sensor holding members whose upper ends are rotatably supported by shafts 7 and 76 on the mounting plate 12. A photoelectric sensor 74, 76, 78, 80 is attached to the sensor holding member 70, 72.

In this embodiment, commercially available line sensors are used as the photoelectric sensors 74, 76, 78, and 80. The line sensor has a large number of minute light detection elements arranged in a straight line. The sensor is located within a through hole formed in the mounting plate 12. A hole 82.84 is transparently provided in the lower part of the sensor holding member 70.72, and the shaft 7 of the hole 82.84
Index holes 86, which are stepped screw holes, are transparently provided in the mounting plate 12 at a predetermined pitch, positioned on a rotation line centered at 7. Adjacent to the holes 82, 84, holes 88, 90 are transparently provided in the holding member 70, 72 so as to be located on the alignment line of the index holes 82 for finely adjusting the angle of the member. 92 and 94 are limit switches having a stopper function, and are attached to the casing 22. Limit switch 92.
．． 94 is connected to a controller (not shown) that drives the pulse motor 52.

The sixth part shows the central processing unit CPU of this apparatus, 100 is a pulse oscillator, 102, 104, 106, and 108 are timing control circuits, which generate timing for driving the photoelectric sensor. 110, 112, 114, 11
6 is a driver, which converts the timing signal generated by the timing control circuit to a level that can drive the sensor. Amplification circuits 118, 120, 122, and 124 differentially amplify output signals from the photoelectric sensors 74, 76, 78, and 80. Slice level setting circuits 126, 128, 130, and 132 slice the analog signal at a constant level and convert it into a digital signal. 13
4 is a counter control circuit, and an oscillator 100
The counting range is determined by comparing the signals from the sensors 74, 76.7'8.80. 136 is a counter circuit, counter control circuit 1
The pulses output from 34 are counted. 138 is an arithmetic circuit, which calculates the center of the thickness of the workpiece 4 based on the numerical value counted by the counter circuit 136;
The correction value in the angle setting input circuit 142 is calculated to determine the distance of the center from the coordinate reference. 14
0 is a register circuit, which stores four types of values obtained by the circuit 138 described above. 146 calculates the angle A of the workpiece 4 based on the sensor interval value. 150 is a display, 14
An angle setting input circuit 2 sets the approximate angle of the workpiece 4 and stores correction values for each angle.

Next, the operation of this embodiment will be explained.

First, the base 10 is arranged so that the lens 26 faces the press end surface of the workpiece 4 sandwiched between the pressure table 6 of the press brake and the press plate 2. Next, rotate the lever 67.62 to move the screen 66.68 to the sensor 74, 76°7.
8. Place it opposite to 80. Next, loosen the screw 160, slide the internal cylinder 20 in its longitudinal direction, set the image reflected on the screen 66, 68 to the desired magnification, and screw 1
60 to fix the inner cylinder 20 to the cylinder 18.

Next, rotate the holder of the lens 26 so that the screen 66
．． Focus the image of work 4 reflected in 68. When the pressure table 6 and the press brake stand 2 and the workpiece 4 are made of the same material and have the same end surface condition, the end surface of the workpiece 4 is painted red in accordance with the green filter 34. Thereby, the contrast between the end face of the workpiece and other parts can be increased, and the end face of the workpiece and the tables 2 and 6 can be distinguished.

In addition, if the end surface condition of the workpiece 4 is different from that of the workpiece 2 and 6,
, 6 and the optical image of the workpiece 4 can be distinguished by the internal circuit of the central processing unit CPU, the colored filter 34. Alternatively, 36 may not be provided. Note that the red filter 36 can be positioned on the optical image of the work by driving the motor 50 and rotating the bevel gear 50.30.

When using the red filter 36, the end face of the workpiece is colored green. Depending on the press angle of the workpiece 4, a sensor 74, 76°78.80
7%, 76 of the axes of the holding members 70, 72 so that
．． The rotation angle around is determined and the shoulder screw 162 is screwed into the desired index hole 86 through the hole 82.84 or hole 88.90 to secure the retaining member 70.72 to the mounting plate 12. After setting the fixed angle of the holding member 70 , 72 , the angle value is input into the circuit 142 . This angle value can be configured to be automatically input to the circuit 142 by a signal from a switch or the like provided for each index hole. The circuit 142 creates an XS coordinate correction value, which will be described later, based on this angle value. Lighting equipment 1
4, and the optical image of the work 4 is irradiated onto the photoelectric sensor 74.76.78.80. At this time, the screens 66, 68 are moved above the front proximity position of the sensors 74, 76, 78, 80 by rotating the levers 62, 67. When the measurement switch 164 is pressed, each sensor 74, 76, 78 The detection signal of .80 is input to the counter control circuit 134. The signal from sensor 74 will now be explained. The signal of sensor 74 is converted by circuit 126 into a digital signal as shown in FIG. 9C. A low-level portion C of the digital signal in FIG. 9C shows a portion where the optical image of the workpiece 4 hits the sensor 74. The counter circuit 136 counts the distance C between XS and XT by the number of pulses, and counts the distance C between XT and XR by the number of pulses. This count value is C
is input to the arithmetic circuit 138, where b+(c/2
)=d is calculated. The calculation circuit 138 calculates the X coordinate value X1 of the center point P1 of the optical image of the workpiece 4 based on the d value and the X coordinate value of XS based on the angle correction value of the circuit 142. By the same operation as above, the arithmetic circuit 138
P2 of the workpiece light image. P3. Calculate the X coordinate value of point P4,
These values are stored in registers 140. The arithmetic circuit 146 first calculates x = l =S i n”X/Jl is calculated.

Using the same principle as above, the angle C2 of the line segment passing through the points P3 and P4 with respect to the Y coordinate axis is calculated. The angle A of the workpiece 4, which is the sum of CI and C2, is digitally displayed on the display 150. The operating wear can obtain the desired pressing force of the pressurizing table 6 by increasing the pressurizing force of the pressurizing table 6 until the workpiece 4 reaches a predetermined angle while watching the above display. This pressing force, ie, the amount of approach of the pressurizing table 6 to the table 2, is stored in a storage device.

When measuring the angle of the workpiece 4, the pressure table 6 is moved slightly away from the table 2 to release the pressure on the workpiece 4.

This is because the workpiece 4 has a tendency to return to its angle slightly when the pressure from the pressure table 6 is released, and this return needs to be taken into account. As shown in FIG. 8, a half mirror 14 is placed between the sensor D and the lens L, and a screen S is placed above the half mirror H, so that the midpoint between the half mirror H and the sensor 0 If the distance a and the distance between the half mirror H and the screen S are set to be the same, the image on the sensor D can be set to the screen S on the sub-light path.
It can be visually observed. In the figure, F is a colored filter and G is a heat insulating filter. In addition, in this example,
As shown in FIG. 10, line sensors 74, 76, 78
, 80. A semi-fixed method using four wires is adopted, but the method is not particularly limited to this method. For example, the 11th
As shown in the figure, an image parallel scanning method using 170.2 line sensors may be adopted. In this method, the angle of the workpiece is measured while moving one sensor 170 on the left and right hooks up and down. By arranging the sensor 170 diagonally and moving it at a pitch of about 1l3 of the sensor length, the entire area of the pressed part of the optical image of the workpiece can be covered. Also, the first
Figure 2 shows an image parallel scanning method using one line sensor 172.

FIG. 13 shows an image rotation scanning method using one line sensor 174.

If the sensor 172 is tilted to use a rotational scanning method, it can be rotated at a pitch of 15 to 18 degrees to cover the entire press area of the workpiece light image. FIG. 14 shows an image rotation scanning method using 176.2 single-element sensors. This method is a single-element version of the method shown in Figure 13 above, and requires a finer scan pitch, but since the reading time for a single element is shorter, the overall measurement time is also more advantageous than the method shown in Figure 12 above. Become. FIG. 15 shows a semi-fixed system using 178.4 to 8 single-element sensors. Although the system shown in FIG. 10 is made into a single element, since the entire area of the workpiece light image 180 cannot be covered, this is the cheapest method in which manual setting is performed each time according to the target workpiece, in accordance with a regular sample. With this method, it is only possible to detect whether or not the press angle of the workpiece matches the sample angle, so the operator presses until the workpiece angle matches the sample angle while watching the display. Place the stand close to the stand.

As described above, the present invention supports the sensor holding member so as to be movable in a preset position within a plane substantially parallel to the lens, so it is possible to handle workpieces with various angular shapes. There is an effect that the angle of the angle can be detected.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram of the press brake, Figure 2 is a plan view, Figure 3 is a sectional view taken along line A-A, Figure 4 is a rear view, Figure 5 is a schematic diagram, and Figure 6 is a block circuit diagram. , Fig. 7 is an explanatory drawing, Fig. 8 is an explanatory drawing, Fig. 9 is an explanatory drawing, Fig. 10 is an explanatory drawing, Fig. 11 is an explanatory drawing, Fig. 12 is an explanatory drawing, Fig. 13 is an explanatory drawing, FIG. 14 is an explanatory diagram, and FIG. 15 is an explanatory diagram. 2...The receiver is the stand, 4...The workpiece, 6...The pressure stand. 10...Base, 12...Mounting plate, 14...
Lighting equipment, 16... Holding body, 18... Cylindrical body, 2
0...Lens, 34.36...Filter, 66
...Screen, 68...Screen, 70.
72...Sensor holding member, 74,76°78.8
0...Photoelectric sensor, 86... Index hole.

Claims (1)

[Claims] 1. A press brake receiver is a device in which an optical image of a workpiece sandwiched between a table and a pressure table is irradiated onto a photoelectric sensor through a lens, and the angle of the workpiece is detected based on a detection signal from the photoelectric sensor. attaching the photoelectric sensor to a sensor holding member;
An angle detection device for press work, characterized in that the sensor holding member is movably supported at a preset location within a plane substantially parallel to the lens.