JPH02195609A - Surface defect detector for finned cable - Google Patents

Abstract

PURPOSE:To eliminate the possibility of an error in the detection of gilled formation for quality control of high accuracy by changing the position of detectors based on the rotational displacement of a guide roller so as to stabilize the relational position between a cylindrical surface of a cable coated layer and each detector. CONSTITUTION:A cable 2 is drawn out of a central hole of a detection plate 1 in a disc shape. So as to engage with the cable 2, guide rollers 6, 6' of cross sectional shape that are composed of semi-cylindrical formation 7 that abuts on a cylindrical surface 3 of a coated layer, and of a step part 8 that abuts on gilled formation 4, 5 of the cable coated layer, are supported by shafts 10, 10'. When the cable is rotated by means of the twisting state and waviness of a core conductor, and the gilled formation 4, 5 of the cable are moved to 4', 5' until they fall in the relational position that can be detected by detectors 14, 15, the rotation of the cable is immediately detected by a rotational displacement detecting part. A surface defect detecting part is rotated in a very short period of time until the angle of displacement of the same direction and the same displacement as that of the cable is given.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a surface defect detector for a finned cable for preventing snow accumulation.

[Prior art] Quality control of coating layer irregularities, defects in the coating layer, deviation from the specified outer diameter, etc. in the cable coating layer extrusion process is carried out in one axial direction,
The unevenness of the cable coating layer can be detected by a contact method that detects the displacement of the cable coating layer in the radial direction by sliding a contact needle from biaxial or multiaxial directions, or by checking the degree of scattering of reflected light from the cable coating layer. This is done using a non-contact method that uses a linear array sensor to detect the width of transmitted light and reflected light. However, cables with fins for preventing snow accumulation, which are becoming increasingly popular, do not have a perfect circular cross-section, and this poses a problem in that sufficient quality control cannot be performed with this type of displacement and width detector.

FIGS. 2(a), 2(b), and 2(c) are diagrams illustrating conventional surface defect detection operations at a standard detection position and two abnormality detection positions, respectively. ), the fin-shaped portion 22.2 of the cable sheathing layer is
Two pairs of displacement detectors (not shown) are fixedly arranged at a constant distance in the two-axis directions of the X-axis and the Y-axis, avoiding the
From the displacement based on that point, irregularities on the coating layer, defects in the coating layer, deviation from the specified outer diameter, etc. are detected.

However, in this defect detection method, the cable rotates due to twisting, waviness, etc. of the core conductor, and
), when the fin-shaped portion 22.22' faces the displacement detector arranged on the X-axis, as shown in FIG. 2(c).
When the fin-shaped portions 22 and 22' face the displacement detectors arranged on the y-axis as shown in FIG. This curvature, which cannot detect deviations from the surface, has the disadvantage that the fin-shaped portion 22.22° is erroneously detected as a convex portion on the coating layer.

[Problems to be solved by the invention] This invention has been made in view of the above points, and
An object of the present invention is to provide a surface defect detector in which the position of a detection part is changed in response to rotational displacement of a fin-shaped part to be detected.

[Means and effects for solving the problems] The present invention includes a pair of guide rollers that contact the fin-shaped portions of the cable sheathing layer and transmit circumferential rotation of the cable sheathing layer;
It comprises a plurality of detectors for detecting defects on the cylindrical surface of the cable sheathing layer, and the position of the plurality of detectors is changed based on the rotational displacement of the guide roller. It acts to always keep the relative position of the surface and each detector constant.

[Embodiment] FIGS. 1(a) and 1(b) are a structural diagram of a rotational displacement detecting section and a structural diagram of a surface defect detecting section, respectively, according to an embodiment of the present invention.

In FIG. 1(a), a hole of a predetermined shape and size is bored in the center of a disc-shaped detection plate 1, through which a cable 2 that has undergone a coating layer extrusion process is drawn out in a direction perpendicular to the drawing.

In order to engage with the cable 2, a guide roller having a cross-sectional shape consisting of a semi-cylindrical portion 7 that contacts the cylindrical surface 3 of the covering layer and a stepped portion 8 that contacts the fin-shaped portion 4.5 of the cable covering layer. 6.6' is journalled on the shaft 10.10'. Further, the shafts 10 and 10' are engaged with each other by springs 11 and 11', and the cable is held with appropriate pressure so that the stepped portion 8 of the guide roller 6 and 6 degrees does not deviate from the fin-shaped portions 4 and 5 of the cable. The rotation of the fin-shaped portion 4.5 in the circumferential direction caused by twisting, waviness, etc. of the core conductor of the cable 2 is thereby accurately transmitted to the detection plate 1.
Furthermore, it is transmitted to the angle detection device 9.

The rotational displacement detection unit configured as described above is configured so that when the cable 2 that has undergone the coating layer extrusion process is pulled out in the direction perpendicular to the drawing, the guide roller 6.6' rotates about the axis 10. It has the advantage that the load is small, and since the cable is held from two directions by two guide rollers, there is no risk of eccentricity of the cable, and the process of extruding the covering layer is not obstructed.

Next, the structure of the surface defect detection section will be explained with reference to FIG. 1(b).

A surface defect detection section equipped with a motor (not shown) installed near the detection plate 1 and controlled by the angle detection device 9 has a cable 2 connected to it as shown by the solid line in FIG. 1(b). Two pairs of optional detectors 12.13 and 14.15 are installed at positions that do not detect the fin-shaped portion 4.5.

Then, the cable rotates due to twisting, waviness, etc. of the core conductor, and the fin-shaped portions 4 and 5 of the cable become 4' as shown by the broken line in FIG. 1(b).

5" and the positional relationship is such that the detectors 14 and 15 detect the wing fins 4" and 5", the rotation of this cable is immediately detected by the rotational displacement detection section described above, and the motor (not shown) is detected. is driven, and the surface defect detection part is rotated within a minute time until it provides a displacement angle of the same direction and displacement amount as the cable displacement. As a result, the detector 12
The position of ~15 is 12°~15' as shown by the broken line in FIG.
The cable coating layer is detected from the original angle.

Now, the detector output detected in this way is the sum of the cable center fluctuation component and the cable surface defect component. Therefore, the detection outputs of the pair of detectors 12 and 13 are set to L.
+2. L13, the cable surface defect component is ΔL12+ΔL13, and the cable center fluctuation component is ΔC, L12=ΔC+ΔL12 L13=−ΔC+ΔL13. Therefore, the cable outer diameter variation ΔD is determined from the sum of the detection outputs L 12+L 13 of the pair of detectors 12.13 as ΔD=L 12+L 13 =ΔL12+ΔL13. This determines the outer diameter of the cable coating layer, and in extreme cases, this value can be detected as a defect in the coating layer.

On the other hand, the detection output of the pair of detectors 12 and 13 is 1□.

Signal C that is 1/2 of the difference in L13, that is, C=<L1
2 L13) / 2=(ΔL12-ΔL13)
ΔL12-ΔL13 of /2+ΔC is a component based on surface defects, and its time constant is considered to be shorter than that of the fluctuation component ΔC at the center of the cable. Therefore, by passing this C through a predetermined time constant circuit and converting it into Cav, a fluctuation component around the cable can be obtained from Cav Aya ΔC. In this way, when the cable center fluctuation is obtained, L12 and L12 and C
, by the following calculation, ΔL 12=L 12−Δ"=L 12 Cav
ΔL 13=L 13+ΔC=L 1. ＋Cav
Net surface defect components ΔL1□ and ΔL13 are obtained, and by discrimination of these values, the degree of unevenness on the surface of the coating layer is detected.

Above, we have described an example in which the rotational displacement of the detection plate is detected, the motor is driven thereby, and the main body of the detecting section follows the rotation. If possible, the configuration can be further simplified by mounting a displacement detector on the detection plate 1. Further, the detection target of the present invention is not limited to cables, but can be applied to detect surface defects of general linear bodies having complicated shapes.

[Effects of the Invention] As described above, according to the present invention, (1) Since the cable is guided by guide rollers, the load on the cable is small.

(2> Compatible with various cables by simply changing the cross-sectional shape of the guide roller.

(3) There is no risk of erroneous detection due to detection of fin-shaped portions, and highly accurate quality control is possible.

It is possible to provide a surface defect detector for a finned cable that has the remarkable effect of:

[Brief explanation of the drawing]

FIGS. 1A and 1B are structural diagrams of a rotational displacement detecting section and a defect detecting section of an embodiment of the present invention, respectively. FIGS. 2A, 2B, and 2C are FIG. 2 is a diagram illustrating a conventional surface defect detection operation at a standard detection position and two types of abnormality detection positions, respectively. 4, 5 ・ 6, 6' 10, 10°11, 11. 12-15 ・Fin shape guide roller angle detector Axial spring detector Patent applicant Hitachi Cable, Ltd.

Claims (1)

[Claims] The guide roller includes a pair of guide rollers that contact the fin-shaped portion of the cable sheathing layer and transmit circumferential rotation of the cable sheathing layer, and a plurality of detectors that detect defects on the cylindrical surface of the cable sheathing layer. A surface defect detector for a finned cable, characterized in that the positions of a plurality of detectors are changed based on the rotational displacement of a roller to maintain a constant positional relationship between each detector and the cylindrical surface of a cable coating layer.