JP2997196B2 - Surface irregularity detection device for linear objects - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear object surface suitable for detecting bump-like defects generated on a cable surface in a covering process of a cable insulator, an inner semiconductive layer, a sheath or the like. The present invention relates to an unevenness detecting device.

[0002]

2. Description of the Related Art In a process of covering an insulator, an inner semiconductive layer, a sheath, and the like of a cable with an extruder, the surface of the cable is mixed due to foreign matter (extruded coating material adhered to the vicinity of an extrusion port and solidified). May produce bumpy defects. When such defects occur, the performance of the cable is degraded or the appearance is deteriorated. So, conventionally,
During the coating process of the cable, the condition of the cable surface is constantly monitored to detect irregularities.

Conventionally, as a device for detecting irregularities on the surface of a cable, a change in the outer diameter of a cable during a run is measured, and the occurrence of irregularities is detected based on whether or not the amount of change has exceeded a set value. Those that do are commonly used. As a method for measuring the change in the outer diameter of the cable during the running, there is the following method.

(First Conventional Example) FIG. 3 is a principle diagram of a first conventional example. In FIG. 4, 9 is a cable, 10 is a bumpy defect, 20, 21 are rollers, 22, 23 are support rods,
Reference numerals 4 and 25 denote springs, and reference numerals 26 and 27 denote displacement-electric signal converters. Roller 2 is driven by springs 24 and 25
The cable 9 is caused to run in the direction of arrow I while pressing 0, 21 against the cable 9 from above and below or from left and right. Then, a change in the outer diameter of the cable 9 is measured by detecting the amount of displacement of the support rods 22 and 23 of the rollers 20 and 21 by the displacement-electric signal converters 26 and 27. For example,
When the bump-shaped defect 10 comes to the position of the roller 20, the roller 20 is displaced upward, the outer diameter dimension increases, and the measured value exceeds a predetermined value. Detect.

(Second Conventional Example) FIG. 4 is a principle view of the second conventional example, and is shown as a cross-sectional view as viewed from a running direction of a cable. In FIG. 4, 9 is a cable, 30 is a light emitting element, and 31 is a light receiving element. The light emitting element 30 applies parallel laser light to the running cable 9, and the laser light not blocked by the cable 9 is detected by the light receiving element 31 facing the light emitting element 30. Then, the amount of change in the outer diameter of the cable 9 is measured based on the output fluctuation of the light receiving element 31. For example, the bumpy defect portion is the light receiving element 31
When the laser beam reaches the position, the ratio of laser light blocking increases and the output of the light receiving element 31 decreases, thereby detecting the presence of the bump-shaped defect. Further, there is a device in which the output of the light receiving element 31 is differentiated with respect to time to detect the output change more sharply.

(Third Conventional Example) A light receiving element such as the light receiving element 31 described above is arranged at a small interval (for example,
Two are provided with an interval of several cm), and one output is subtracted from the other output. In this way, a change in the length of the cable outer diameter in the length direction is detected. For example, when the bump-shaped defect comes to the position of one of the light receiving elements, the output of the light receiving element decreases, but the output of the other light receiving element remains unchanged, and a difference occurs between the two outputs. By detecting the difference, the presence of the bumpy defect is detected.

Conventionally, the occurrence of irregularities on the cable surface has been detected in this manner. At this time, a threshold for detection is set in advance using a digital switch, a volume, or the like.
It was determined that there was unevenness when the outer diameter varied more than that.

A conventional document relating to such a cable surface unevenness detecting device is disclosed in, for example,
No. 5764, Japanese Utility Model Application No. Sho 60-70009, Japanese Patent Application Laid-Open No. 62-3602
And JP-A-4-348208.

[0009]

However, even in a normal portion of the cable surface, the twist of the core twist, the wrap of the core-repressed tape, the winding wrinkles of the metal tape wound in a core shape, etc. appear on the surface as they are. As a result, unevenness may occur. Therefore, the output voltage of the cable outer diameter detecting means slightly fluctuates even in a normal portion as shown in FIG.

In such a state, when a bump-like defect on the cable surface is detected, as in the first and second prior art examples, the defect is detected when the detection output of the cable outer diameter exceeds a threshold value. the technique of, there is a problem that it is difficult to set a threshold value D _S of the detection to a proper value. That is, it is difficult to grasp the dimensions of the irregularities of the normal part in advance, and the detection output difference ΔD between the irregularities of the abnormal part and the irregularities of the normal part is very small with respect to the threshold level, and the threshold is narrow. It must be set within a range, and setting is difficult.

[0011] Under such difficult, if set too high a threshold D _S, there is a possibility that a leak detected until abnormal irregularities such as nodular defects. Conversely, when the threshold value D _S is set too low, it often erroneously detected as abnormal irregularities irregularities normal portion. Further, as in the third conventional example described above, in the method of detecting the presence of the bump-shaped defect portion by detecting the difference in outer diameter between two points slightly separated in the running direction of the cable by exceeding a threshold value, the cable outside When the diameter fluctuates gently, there is a problem that even if the diameter fluctuates to an abnormal level, the difference in the outer diameter between the two points does not appear so large that the fluctuation of the outer diameter cannot be detected.

The present invention solves such a problem and provides an unevenness detecting device for a cable surface capable of reliably distinguishing and detecting normal unevenness and abnormal unevenness irrespective of the fluctuation of the cable outer diameter. The task is to provide.

[0013]

In order to solve the above-mentioned problems, a cable surface unevenness detecting device according to the present invention is arranged so as to detect the outer diameter of the same cross section of a linear object in a running line in a circumferential direction of a cross section. Three or more outer diameter detecting means provided at different angles,
A calculation for outputting a signal corresponding to the difference between the output of one of the outer diameter detecting means of the outer diameter detecting means and the average value of the output of the other outer diameter detecting means for each outer diameter detecting means. Means,
Detection signal output means for outputting a detection signal when at least one output of the arithmetic means exceeds a threshold value.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a diagram illustrating an arrangement relationship between a light emitting element and a light receiving element with respect to a cable. In FIG. 1, 1 to 4 are light emitting elements, 5 to 8 are light receiving elements, 9 is a cable, and 10 is a bumpy defect.

The light-emitting elements 1 to 4 are arranged at a predetermined angle in the circumferential direction of the same cross section of the cable 9 running in the axial direction, and irradiate the cable 9 with a parallel laser beam. ing. On the other hand, light receiving elements 5 to 8 are arranged on opposite sides of the light emitting elements 1 to 4 with the cable 9 interposed therebetween, and output a signal corresponding to the amount of received laser light. The output of the light receiving elements 5 to 8 is blocked by the laser light cable 9 if the outer diameter of the cable 9 is large, and is blocked by the laser light cable 9 if the outer diameter is small. As the ratio becomes smaller,
A value corresponding to the outer diameter of the cable 9 is shown. In the state shown in FIG. 1, the light receiving elements 5 to 7 output detection signals corresponding to the normal outer diameters D _{1 to} D ₃ of the cable 9, and
Outputs a detection signal corresponding to the value D ₄ height is applied in nodular defect 10 to the normal outside diameter of the cable. Less than,
Outputs of the light receiving elements 5 to 8 are indicated by D _{1 to} D ₄ .

FIG. 2 is a block diagram showing a schematic configuration of a cable surface unevenness detecting device. Reference numerals 5 and 6 correspond to those in FIG. 1, 11 is an arithmetic circuit, 12 to 15 are comparison circuits, and 16 is an OR circuit. The arithmetic circuit 11 receives the outputs from the light receiving elements 5 to 8 and receives the absolute value of the difference between one of them and the average value of the other outputs, that is,

Σ ₁ = │D _1- (D ₂ + D ₃ + D ₄ ) / 3│

Σ ₂ = │D _2- (D ₁ + D ₃ + D ₄ ) / 3│

Σ ₃ = │D _3- (D ₁ + D ₂ + D ₄ ) / 3│

Equation 4] _{σ 4 = │D 4 - (D} 1 + D 2 + D 3) / outputting a 3￨.

The comparison circuits 12 to 15 compare the outputs σ _{1 to} σ ₄ of the arithmetic circuit 11 with the threshold value, and output a signal indicating that the output σ _{1 to} σ ₄ exceeds the threshold value. And OR
The circuit 16 outputs a detection signal when any of the comparison circuits 12 to 15 outputs a signal.

The relationship between the outputs will be described with reference to the drawing. The output D ₄ of the light receiving element 8 in FIG. 1 fluctuates slightly in a normal portion and outputs in a bump-like defect portion as shown by the solid line in FIG. Becomes larger. On the other hand, the respective outputs D _{1 to} D ₃ of the light receiving elements 5 to 7 fluctuate as small as the normal part of the output D ₄ of the light receiving element 8, but their average values D _M are shown in FIG.
It becomes almost constant as shown by the one-dot chain line in (b).

The absolute value σ of the difference between the output D ₄ of the light receiving element 8 and the average value of the outputs D _{1 to} D ₃ of the light receiving elements 5 to 7
FIG. ₄ is an enlarged view of FIG. In comparison with the threshold D _S in the comparison circuit 15, the absolute value of the difference sigma ₄
When but exceeding the threshold value D _S, comparator circuit 15 outputs a signal.

[0020] In this case, on the level of threshold D _S, the difference ΔD between the absolute value sigma ₄ of the difference between the absolute value sigma ₄ a normal part of the difference between the abnormal portion 5 (a) to become much larger than that of And the threshold value D _S , the abnormal part and the normal part can be clearly distinguished.

[0021]

As described above, the unevenness detecting device for the surface of a linear object according to the present invention detects the outer diameter of the same cross-section of a linear object in a running line by changing the angle in the circumferential direction of the cross-section. An abnormality is determined based on the difference between one detection output and the average value of the other detection outputs. As a result, normal irregularities and abnormal irregularities can be reliably determined and detected irrespective of the fluctuation of the outer diameter of the linear object.

[Brief description of the drawings]

FIG. 1 is a diagram showing an arrangement relationship between a light emitting element and a light receiving element with respect to a cable;

FIG. 2 is a block diagram showing a schematic configuration of a cable surface unevenness detecting device;

FIG. 3 is a principle diagram of a first conventional example.

FIG. 4 is a principle diagram of a second conventional example.

FIG. 5 is a diagram for explaining a principle of detecting irregularities on a cable surface;

[Explanation of symbols]

 1 to 4, 30 light emitting element 5 to 8, 31 light receiving element 9 cable 10 bump-shaped defect portion 11 arithmetic circuit 12 to 15 comparison circuit 16 OR circuit 20, 21 roller 22, 23 support rod 24, 25 spring 26, 27 displacement- Electric signal converter 30 Light emitting element 31 Light receiving element

Claims (1)

(57) [Claims] A linear object (9) having a different angle in the circumferential direction of the cross section so as to detect the outer diameter of the same cross section of the linear object (9) in the running line.
One or more outer diameter detecting means (5 to 8);
8), a signal corresponding to the difference between the output of one of the outer diameter detecting means and the average of the outputs of the other outer diameter detecting means is output for each of the outer diameter detecting means (5 to 8). And a detection signal output means (12 to 16) for outputting a detection signal when at least one output of the calculation means (11) exceeds a threshold value. An unevenness detector for the surface of an object.