JPH0145384B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a positioning method in a manufacturing process or an inspection process of a ball, such as a tennis ball, which has a dumbbell-shaped seam line as shown in FIG. 2 on its surface.

Generally, the manufacturing process of balls such as tennis balls,
In the inspection process, it is absolutely necessary to position the ball in a fixed position when measuring stamp marks and compression. That is, the stamp is placed on the waist of the dumbbell ball as shown in Figure 1a, and the compression must be measured at the hip area as shown in Figure 1b or the waist area as shown in Figure 1c according to the JTA standard. . Conventionally, automatic ball positioning for this purpose has been studied using an image sensor method, but this method does not clearly capture the seam on the ball surface, is very time consuming, and requires high cost for the positioning device. It was impossible to implement this method due to problems such as high cost. For this reason, we currently rely on manual labor, but the work requires positioning accuracy and is a highly repetitive task, which puts a heavy burden on the workers, making it impossible to work continuously for long periods of time, and the positioning accuracy due to fatigue. We cannot ignore the decline in . Moreover, this also placed a limit on the improvement of processing capacity. Except for this positioning work, the equipment for the previous and subsequent processes is automated, so if it becomes possible to automatically position the ball, it will be possible to fully automate stamp marks and compression measurements, which could lead to human error caused by simple work. This will greatly contribute to labor savings and cost reductions.

The present invention provides a means to solve these conventional problems, and provides a ball positioning method that enables automation of ball positioning, eliminates positioning errors due to individual differences, and performs highly accurate positioning. The purpose is to provide.

Hereinafter, the present invention will be explained in detail based on the drawings.

First, to explain the principle of the present invention using a tennis ball as an example, the surface of the tennis ball is formed by bonding two Melton dumbbells 1, 1 of the same shape as shown in FIGS. 2 and 3. , the pasted part is called a seam, and because it appears in a linear shape, the line is called a seam line. Each dumbbell 1 has two hip parts 2, 2 which are arc-shaped parts on both sides, and one waist part 3 in the middle part.
It consists of Here, assuming that the center points of the hip portions 2, 2 are A1, A2, and the center of the waist portion 3, that is, the midpoint between the center points A1, A2, is B, the dumbbell 1 has the following properties.

(a) Each hip portion 2, 2 of the dumbbell 1 forms a part of a circle with a radius of R, and its center is at the center point A above.
1, matches A2.

(b) The center of the circle is on the perpendicular bisector M′ of the chord L′.
That is, the positions at a radius R inward from the point where the perpendicular bisector M' of the chord L' intersects with the circular arc portion of the hip portion 2 are the center points A1 and A2 of the circle.

(c) If the center axis A1-A2 connecting the center point A1 and center point A2 of either dumbbell 1 is considered as the rotation axis, then the midpoint B between both dumbbells 1, 1,
Both points B are on the equator (see Figure 6).

The positions of points A1, A2, and B can be determined using the properties of (a), (b), and (c) above. In FIG. 4, when the ball 4 rotates around an axis X passing through its center, the trajectory K of the intersection of the axis Z perpendicular to the axis X and passing through the center of the ball 4 and the surface of the ball 4
intersects with the dumbbell seam line 5 at several places. The number of intersections P is limited to three types: 2, 3, and 4. Therefore, when expanded, the trajectory K when there are four intersection points P becomes as shown in Fig. 5,
The part where the length between two adjacent intersection points is the shortest (in the example shown, between P1 and P2) is always the chord L'. That is, the intersection points P1 and P2 of one dumbbell 1 are always in a part of the circle forming the hip part 2, and the other intersection points are not necessarily in a part of the circle forming the hip part 2. For example, in the case of point P4 of one dumbbell 1,
The line segment between the P4 point and the P3 point does not form a chord because the P4 point is not in a part of the circle. Therefore, the shortest locus in FIG. 4, that is, the arc L, corresponds to the chord L', and the perpendicular bisector M' of this chord L' (the arc L in FIG.
If the ball 4 is rotated by a radius R from the seam line 5 (the intersection G of the arc of the hip part 2 and the perpendicular bisector M') in the direction corresponding to the imaginary perpendicular bisector m of the chord l, , center points A1 and A2 can be determined. In addition,
The midpoint N of the chord L' corresponds to the center n of the arc L in FIG.

Next, as shown in FIG. 6, the pair of center points A1 and A2 in one dumbbell 1 are opposite to each other, and due to the property (c) above, the center point A1 and the center point A
The center axis A1-A2 connecting 2 is the rotation axis, and the intermediate points B and B are on the equator, but the longer arc length on the equator between the two intersections Q and Q between the equator and the seam line 5 Alternatively, by taking the shorter midpoint, the positions of midpoints B and B can be determined.

The above principle makes it possible to automatically position the ball 4 at the center points A1, A2 of the hip portion 2 of the dumbbell 1 or at the midpoint B of the waist portion 3. In particular, as described above, the most important point is to find the rotation axis of the ball 4 where the number of intersections P between the dumbbell seam line 5 and the trajectory K is four.

Next, a first invention based on the above-mentioned principle will be explained using FIG. 7 showing one embodiment thereof. In the following explanation, the same reference numerals will be used for parts corresponding to the explanation of the principle described above.

In FIG. 7, the ball 4 has an origin O at the intersection of three mutually orthogonal axes X, Y, and Z.
The ball 4 is supported on a support member 6 that can be raised and lowered so that the center point of the ball 4 coincides with the center point of the ball 4 . This ball 4 is rotatable around the axis X by a pair of rotary drive devices 7, 7 located on the axis X, and
It is rotatable around the axis Y by a pair of rotary drive devices 8, 8 located on the axis Y. Specifically, the rotary drive devices 7 and 8 have rotary shafts 10 having clamping portions 9 at their tips located on the axes X and Y, respectively, and a drive portion 11 that rotates the rotary shafts 10 in both forward and reverse directions. has a built-in rotation frequency detection device and a frequency drive device (not shown). Each of the rotary drive devices 7 and 8 is attached to a fluid pressure cylinder (not shown), a screw shaft, a link mechanism, etc. so as to be able to move forward and backward in the axial direction. and 8, 8 clamp the ball 4 with the clamping parts 9, 9 at the tip in the forward state,
The balls 4 are rotated around their respective axes X or Y. It should be noted that when the ball 4 is held and rotated, the support member 6 is lowered and separated from the ball 4.
Further, although the axial movement of the rotary drive devices 7 and 8 is configured such that the entire devices 7 and 8 are moved, the rotary shaft 1
It is also possible to have a configuration in which only the drive unit 0 moves forward and backward with respect to the drive unit 11.

Further, above the ball 4, a sensor 12 for detecting the seam line 5 on the surface of the ball 4 is located on the axis Z, and the axis of the sensor 12 is located on the axis Z.
It is set in a fixed state in accordance with . As this sensor 12, for example, a reflective optical sensor 15 having a light emitting part 13 and a light receiving part 14 as shown in FIG.
is used. That is, light is projected onto the surface of the rotating ball 4, the amount of light reflected from the part of the Melton dumbbell 1 and the seam line 5 is detected, and an output signal is generated based on the difference. By using such an optical sensor 15, the seam line 5 can be detected reliably. This output signal is sent to a control unit (not shown),
Based on this, the rotation drive devices 7 and 8 are automatically controlled. Note that the position where the seam line 5 is detected is output as the seam line 5 center by dividing the width S of the seam line 5 into two in order to improve positioning accuracy. Further, various data such as the rotation frequency are stored in the control section during each axis processing cycle. With such a device, the ball 4 set in an arbitrary direction is rotated, the dumbbell-shaped seam lines 5 on the surface are searched by the sensor 12, and the distance (rotation angle) between the seam lines 5 and the number of intersection points P are detected. Ball 4 by memory and data processing of this
The hip part (circular part on both sides) 2,
The center points A1, A2 of the waist portion 3 and the midpoint B of the waist portion 3 can be positioned upwardly, that is, on the axis Z.

Hereinafter, a method for positioning the center points A1 and A2 of the hip portion 2 on one axis Z among the three axes X, Y, and Z will be explained. The flowchart is shown in FIG. 9.

First, the ball 4 is set on the support member 6 in an arbitrary direction, and the rotary drive devices 7, 7 on the axis The number of outputs (the number of intersections with the seam line 5) in one rotation is detected.
(At this time, measure the rotation angle between adjacent seam lines at the same time.) Since the ultimate goal is to have four outputs per rotation, two or three outputs are inappropriate and require additional rotations. be. That is, the ball 4 is further moved from the arbitrary set original position to the axis X.
Rotate around a certain angle. And the ball 4
is held between the rotary drive devices 8, 8 on the axis Y, and
The sensor 12 similarly detects the number of outputs per revolution. Of course, at this time, the rotary drive devices 7, 7 on the axis X are moved back and are in a position separated from the ball 4. If the output is still not four, the above-mentioned process is repeated again, and this time the ball 4 is rotated around the axis X. Experimentally, if such additional rotations are repeated at most twice, it is possible to obtain four outputs per rotation. In this way, the axis X or Y where the detection of the seam line 5 by the sensor 12 in one rotation of the ball 4 produces four outputs is determined.

Here, it is assumed that four outputs are obtained per revolution when the ball 4 rotates around the axis X. Next, the rotation of the axis X is controlled so that the center n of the arc L having the minimum rotation angle among the outputs is positioned on the axis Z (directly above) corresponding to the axis of the sensor 12. FIG. 7 shows the state at this time. As described above, the arc L corresponds to the chord L' in FIG. 5, and its position can be easily determined from the rotation angle. Next, move the ball 4 to the axis Y
It is held between the upper rotary drive devices 8, 8 and rotated around the axis Y. At this time, the locus of the axis Z corresponding to the axis of the sensor 12 with respect to the surface of the ball 4 coincides with the direction of the virtual perpendicular bisector m of the chord l of the arc L. In other words, in FIG. 5, the locus corresponds to the perpendicular bisector M' of the chord L'. Then, during the rotation around the axis Y, the sensor 12 detects the seam line 5 to be used as a reference. That is, the reference seam line 5 exists at two locations, one at a short distance from the center n within the radius R in FIG. 2, and the other at a far distance from the center n in the same direction.

First, in the case of detecting the seam line 5 located at a short distance, it is sufficient to rotate the ball 4 by a small angle within the radius R described above. However, if the sensor 12 does not output an output even if the sensor 12 is rotated by a predetermined angle corresponding to approximately the radius R, the rotation is in the opposite direction. After that, if the ball 4 is further reversely rotated around the axis Y by the radius R of the hip portion 2 of the seam line 5 from the detected position, the center point A1 of the hip portion 2
Alternatively, A2 is directly above, and the center points A1 and A2 can be positioned on the axis Z. In addition, if the sensor 12 output does not come out even if the ball 4 is rotated by an angle corresponding to the radius R, as described above, instead of rotating the ball 4 in the opposite direction, rotate it in the same direction by nearly one rotation (360 degrees) to achieve the desired purpose. A method may also be used in which the seam line 5 is detected at a position a short distance away from the ball 4, and then the ball 4 is further rotated by a radius R in the same direction. In this way, the load on the device due to reverse rotation is eliminated, and the detection time can also be shortened.

Next, in the case of detecting a seam line 5 located at a far distance from the center n, the sensor 12 will detect two seam lines 5. First, the seam line 5 at a short distance is detected in the same manner as above, and then the ball 4 is rotated in the same direction or in the opposite direction, and the seam line detected first is detected as the target seam line 5 at a long distance. shall be. Then, if the ball 4 is further rotated in the same direction around the axis Y by the radius R from this position, the center point A1 or A2 of the hip portion 2
is directly above, and the center points A1 and A2 can be positioned on the axis Z.

In addition, in the initial process of searching for the number of outputs,
In the above method, the ball 4 is rotated around the axis X, but it may also be rotated around the axis Y.

Next, a second invention in which the midpoint B of the waist portion 3 is set on one axis Z of the three axes X, Y, and Z will be described. FIG. 10 shows one embodiment of this invention, but since the apparatus is exactly the same as the first invention, the explanation thereof will be omitted. The method is the same as the first invention up to the step of finding the center points A1 and A2 of the hip portion 2 on the axis Z, so the explanation up to that point will be omitted. That is, as shown in the flowchart of FIG. 11, the process of positioning the intermediate point B is added to the first invention. Now center point A
1 and A2 are found on the axis Z, the two intermediate points B and B are on the plane containing the axes X and Y. Next, the ball 4 is rotated 90 degrees around the axis X by the rotary drive devices 7, 7, and then held by the rotary drive devices 8, 8 on the axis Y, and then the rotary drive devices 7, 7 are retracted. , rotates the ball 4 around the axis Y. At this time, since the center points A1 and A2 are on the axis Y, the trajectory of the sensor 12 due to the rotation of the ball 4 around the axis Y coincides with the equator where the intermediate points B and B exist, and this causes the output of the seam line 5 and the rotation Waist part 3 from angle
Intermediate points B and B can be positioned directly above at will. That is, the seam line 5 in the rotational direction around the axis Y
The intermediate points B, B can be positioned on the axis Z by rotating half of the rotation angle of the longer or shorter length between them from the seam line 5 in the respective directions.

The same effect can be obtained by rotating the ball 4 90 degrees around the axis Y after finding the center points A1 and A2 on the axis Z, and then positioning it by rotating around the axis X.

Next, a third invention in which the ball 4 is positioned in another direction at the intermediate point B in the waist portion 3 will be described.

FIG. 12 shows one embodiment of the invention, and FIGS. 7 and 10 show embodiments of the first and second inventions, respectively.
The difference from the figure is that the ball 4 can also be rotated around the axis Z by a rotary drive device (not shown), and that the ball 4 is placed on a virtual plane including two of the three axes X, Y, and Z. This is because a second sensor 16 is provided.
As this second sensor 16, an optical sensor 15 similar to the sensor 12 on the axis Z is used. Therefore, to explain the positioning method, as shown in the flowchart of FIG. The second sensor 16 detects the seam line 5. Then, by rotating from the seam line 5 in each direction by half the rotation angle of the longer or shorter length between the seam lines 5 on the equator in the rotation direction around the axis Z, the intermediate points B and B are The second sensor 16 can be positioned on the axis T passing through the origin O of the second sensor 16 located on the virtual plane.

In this invention, the center point A in the second invention
1. After finding A2 on the axis Z, it is possible to omit the rotation of the ball 4 by 90 degrees around the axis Points B and B can be positioned on an arbitrary axis T passing through the origin O on the virtual plane.

In addition, in each of the first, second, and third inventions described above, increasing the number of sensors 12 installed as shown in FIG. The required number of rotations (degrees) can be reduced, and processing time can be shortened.
Furthermore, in the third invention, FIGS.
As shown in the figure, by increasing the number of sensors 16 and 12 installed, the required number of rotations (degrees) around the three axes X, Y, and Z can be reduced. However, if the sensors 16 and 12 are on the rotation axes X, Y, and Z, these sensors 1
6 and 12 must be built into the center of the rotational drive device for each shaft.

Further, as a method for verifying the positional deviation of the automatically positioned ball 4 according to each of the first, second and third inventions, as shown in FIG. sensor 1
7... is provided, the sensors 17... and the seam line 5 are superimposed, and if all three detect the seam line, it is determined that there is no deviation.As shown in FIG. A possible method is to use a single sensor 17 fixed at a position that coincides with the arcuate portion 2 of the ball 4 to detect the detected angle of the seam line of the rotating ball 4. That is, in the latter method, the ball 4 is rotated around the axis Z by a drive device with a built-in rotation degree detection mechanism, and if the rotation degree at which the seam line is detected is greater than a predetermined value,
This is a method to determine that there is no deviation.

Figure 16 shows a positioning section 1 to which the method of the present invention is applied.
8 is a simplified plan view of the inspection device in which the number In this figure, the testing device for the compression test of balls 4 consists of an input section 19, a positioning section 18, a verification section 20, a compression measurement section 21, and an ejection section 22. The ball 4 thrown in is positioned in the positioning section 18 using the above method, and then checked for positional deviation in the verification section 20 (as described in FIG. 14 or 15), and the ball 4 that is correctly positioned is checked. 4 is sent to the next step, the compression measuring section 21, where a predetermined operation is performed. After that, the ball 4 is transferred to the discharge section 22.
from there to the next work process. In this way, it is possible to fully automate a series of inspection work processes, which has great effects.

In the first to third inventions described above, the tennis ball 4 is used as an example, but other than tennis balls may also be used, such as the dumbbells 1 and 1 described above, which have the same shape and whose both ends are part of a circle. The present invention can be applied to any spherical object that is to be bonded (including objects other than bonding) by detecting seam lines on the surface (and objects corresponding thereto).

The present invention has effectively achieved its intended purpose with the configuration detailed above. In particular, as the ball 4 rotates and the sensor 12 detects the dumbbell-shaped seam line 5 on the surface of the ball 4, the center point A1, A2 of the hip part (circular arc-shaped part on both sides) 2 of the seam line 5 or the waist part 3 is detected. Since this method positions the intermediate point B at a fixed position, it is possible to automate the positioning of the ball 4, which enables highly accurate positioning in a short time and eliminates positioning errors caused by individual differences between workers as in the past. It can be resolved. Even if some error occurs, it depends on the accuracy of the device, and the degree of error is almost uniform, so large variations between workers or among the same worker can be prevented. This eliminates worker fatigue, which greatly affects manual positioning accuracy, and allows continuous work.
Furthermore, by automating the positioning work, a series of manufacturing processes such as stamp marks and compression measurements, and inspection processes can be completely automated, making it possible to significantly reduce costs by reducing the number of personnel.

[Brief explanation of drawings]

Figure 1 is a plan view of the ball showing the stamp position and compression measurement position, Figure 2 is a developed plan view of Melton dumbbells to explain the principle of the invention, and Figure 3 is the position of two Melton dumbbells. FIG. 4 is a perspective view of a tennis ball to explain the principle of positioning; FIG. 5 is a developed plan view of the Melton dumbbell in FIG. 4;
FIG. 6 is a front view of a tennis ball for explaining the principle, FIG. 7 is a simplified perspective view showing an embodiment of the first invention, FIG. 8 is a side view of the optical sensor, and FIG. 9 is a diagram of the first embodiment. A flowchart of the invention, FIG. 10 is a simplified perspective view showing an embodiment of the second invention, FIG. 11 is a flowchart of the same, and FIG. 12 is a simplified perspective view showing an embodiment of the third invention. Figure 13 is a flowchart of the same, Figures 14, 15, and 16 are simplified perspective views showing other examples of sensor installation, and Figures 17 and 18 are simplified diagrams for explaining the verification method after positioning, respectively. , FIG. 19 is a simplified plan view of an example of an inspection apparatus to which the method of the present invention is applied. 2...hip part (arc shaped part), 4... ball, 5...
Dumbbell-shaped seam line, 12...Sensor, 16
...Second sensor, X, Y, Z...axis, O...origin,
A1, A2...Center point, B...Intermediate point, L...Circular arc, l
...chord, R...radius, m...perpendicular bisector, n...center.

Claims (1)

[Scope of Claims] 1. The ball 4 is rotatably supported so that the center point of the ball 4 coincides with the origin O at the intersection of three axes X, Y, and Z that are perpendicular to each other, and A sensor 12 for detecting the dumbbell-shaped seam line 5 on the surface of the ball 4 is provided on one axis Z among the three axes X, Y, and Z, and the ball 4 is
Rotate around one axis X and/or the other Y axis,
Find the axis at which the detection of the seam line 5 of the sensor 12 during one rotation of the ball 4 produces four outputs, and then rotate the ball 4 around the axis to find the center n of the shortest arc L between the outputs. , the ball 4 is positioned on the above-mentioned axis Z corresponding to the axis of the sensor 12, and then the ball 4 is positioned on the axis Z corresponding to the axis of the sensor 12.
The ball 4 is rotated so that the locus on the surface coincides with the direction of the virtual perpendicular bisector m of the chord l of the arc L, and the seam line 5 to be used as a reference is detected by the sensor 12.
is detected, and then the ball 4 is rotated in the opposite direction or the same direction by the radius R of the arcuate portions 2, 2 on both sides of the seam line 5 from the detected position. The center points A1 and A2 are the three axes X,
A ball positioning method characterized by positioning the ball on one axis Z, which corresponds to the axis of the sensor 12 among Y and Z. 2. The intersection of three mutually orthogonal axes A sensor 12 for detecting the dumbbell-shaped seam line 5 on the surface of the ball 4 is provided on one axis Z of Z, and the ball 4 is
Rotate around one axis X and/or the other Y axis,
Find the axis at which the detection of the seam line 5 of the sensor 12 during one rotation of the ball 4 produces four outputs, and then rotate the ball 4 around the axis to find the center n of the shortest arc L between the outputs. , the ball 4 is positioned on the above-mentioned axis Z corresponding to the axis of the sensor 12, and then the ball 4 is positioned on the axis Z corresponding to the axis of the sensor 12.
The ball 4 is rotated so that the locus on the surface coincides with the direction of the virtual perpendicular bisector m of the chord l of the arc L, and the seam line 5 to be used as a reference is detected by the sensor 12.
is detected, and then the ball 4 is rotated in the opposite direction or the same direction by the radius R of the arcuate portions 2, 2 on both sides of the seam line 5 from the detected position, and the center of the arcuate portions 2, 2 on both sides is rotated from the detected position. Points A1 and A2 are found on the one axis Z corresponding to the axis of the sensor 12, and then the ball 4 is rotated 90 degrees around one of the other two axes X and Y, and then the points A1 and A2 are determined in the orthogonal direction. The sensor 12 determines the midpoints B, B of the seam line 5 in the rotational direction, and then the midpoints B, B are set between the three axes X, Y, and Z. A ball positioning method characterized by positioning the ball on one axis Z corresponding to the axis of the sensor 12. 3 The intersection of the three mutually orthogonal axes X, Y, Z is set as the origin O, and the ball 4 is rotatably supported so that the center point of the ball 4 coincides with the origin O, and the three axes X, Y, A sensor 12 for detecting the dumbbell-shaped seam line 5 on the surface of the ball 4 is provided on one axis Z of Z, and the ball 4 is
Rotate around one axis X and/or the other Y axis,
Find the axis at which the detection of the seam line 5 of the sensor 12 during one rotation of the ball 4 produces four outputs, and then rotate the ball 4 around the axis to find the center n of the shortest arc L between the outputs. , the ball 4 is positioned on the above-mentioned axis Z corresponding to the axis of the sensor 12, and then the ball 4 is positioned on the axis Z corresponding to the axis of the sensor 12.
The ball 4 is rotated so that the locus on the surface coincides with the direction of the virtual perpendicular bisector m of the chord l of the arc L, and the seam line 5 to be used as a reference is detected by the sensor 12.
is detected, and then the ball 4 is rotated in the opposite direction or the same direction by the radius R of the arcuate portions 2, 2 on both sides of the seam line 5 from the detected position, and the center of the arcuate portions 2, 2 on both sides is rotated from the detected position. Points A1 and A2 are found on the axis Z, which corresponds to the axis of the sensor 12, and from this state, the ball 4 is moved along the axis Z, which corresponds to the axis of the sensor 12.
The seam line 5 is detected by the second sensor 16 on a virtual plane including the other two axes X and Y.
A method for positioning a ball, comprising: determining intermediate points B, B in the rotational direction, and positioning the intermediate points B, B on the virtual plane and on one axis T passing through the origin O.