JPS585607A - Device for checking finished state of inner surface of concrete tube - Google Patents

Abstract

PURPOSE:To ensure the checking of the finished state of the inner surface simply by irradiating light on the concrete tube, photographing the part by a sensor, and comparing the change in the detected value due to the change in brightness with a reference value. CONSTITUTION:The light is irradiated from a light projecting device 4 on the inner surface 3a through a light screening plate 5 from the front side of the concrete tube A. The irradiated plate 5 from the front side of the concrete tube A. The irradiated part is photographed by the image sensor 6 from the rear side. The output is inputted to a comparator 10 through a low pass filter 7, a differentiating circuit 8, and a low pass filter 9, and compared with the reference value. When the output from the filter 9 exceeds the reference value, it is judged that the disturbance brightness is present on the inner surface 3a of the tube A due to the poor part wherein concave and convex parts exceed the specified value. The signal is sent to a warning circuit 11. Therefore the check of the finished state of the inner surface can be performed simply and accurately.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for inspecting the inner surface finish of concrete cylinders such as concrete piles and utility poles.

& 2 ゛ As shown in Fig. 1, the concrete cylinder A is made of a donut-shaped flat iron plate 1 having a plurality of small holes 1a at equal intervals on the same circumference, and a plurality of plates arranged coaxially at predetermined intervals. A steel frame assembly made by inserting the iron rods 2 into the small holes 1a of each plate 1 is inserted into a mold (not shown), a predetermined amount of concrete is poured into the mold, and a centrifugal force is applied to the concrete. The mold is rotated for a predetermined period of time in order to function, and the cylindrical concrete 3 is solidified during the rotation. Note that this formed cylindrical body A
The inner periphery of is almost circular at every point.However, if the amount of concrete to be poured is the specified amount!
If the amount is too small, the inner peripheral portion of the plate 1 may protrude from the inner surface of the cylinder A, that is, the inner surface 3a of the concrete 8, resulting in defective products. The inspection of its quality, that is, the inspection of the internal finish of the cylinder A, is carried out by one person.
An electric light is irradiated onto the inner surface from the front, and another person visually observes the inner surface from the rear, and the quality is determined by checking whether there is any disturbance in the change in the brightness of the inner surface.

Therefore, the inspection requires manpower and time, and since the cylindrical body A is quite long, it is difficult to inspect it.

This invention has been made in view of the above-mentioned circumstances, and includes a projector that illuminates the inner surface of the cylinder A from the front, an image sensor disposed behind the cylinder A, and a projector that illuminates the inner surface of the cylinder A. It is an object of the present invention to provide a device which electrically detects the degree of disturbance in the change in the brightness of the inner surface and inspects the quality of the inner surface finish of the cylinder A.Examples will be described in detail below. For the purpose of explanation, the left side in FIG. 2 will be referred to as the front of the cylinder A, and the right side will be referred to as the rear thereof.

Reference numeral 4 denotes a light projection device arranged in front of the cylinder A and approximately coaxially with the cylinder A for illuminating the inner surface of the cylinder.

Reference numeral 5 denotes a light-shielding plate (disk) which is arranged behind the light projector 4 and substantially coaxially with the cylinder A, and whose diameter is smaller than the inner diameter of the cylinder A. It is designed to prevent direct irradiation of light.

This is an image sensor (line image sensor in the embodiment) arranged on the axis for photographing inside the cylinder A. Note that the light-receiving elements of the sensor 6 are arranged in the diametrical direction of the cylindrical body A, which passes approximately through the center of the cylindrical body A in the image taken by the camera of the sensor 6.

7 is a filter connected to the output side of the cell 6.

8 is a differential circuit (differential amplifier circuit in the embodiment) connected to the output side of the filter 7.

9 is a low-pass filter connected to the output side of the circuit 8.

10 is connected to the output side of the circuit 9, and outputs the output value from the circuit 9 and a preset reference value (the area indicated by the dashed-dotted line 5i-82 and the area 83 to S4 in each (e) of Fig. 3.4). This is a circuit that compares.

A warning circuit 11 is connected to the output side of the circuit 10 and is activated when the output value from the circuit 9 exceeds the reference value.

Furthermore, the operation of this embodiment will be described.

5. The light projector 4 illuminates the inner surface 3a of the cylindrical body A, and the sensor 6 images the inner surface 8a. At this time, the light shielding plate 5 allows
Since the light from the light projector 4 does not directly enter the sensor 6, a clear image as shown in each (a) of Fig. 3.4 can be obtained. Furthermore, Fig. 3 (A) shows an image of a long cylinder A in which the inner circumferential portion of plate 1 does not protrude from the inner surface 8a, and Fig. 4 (a) shows an image of a defective cylindrical body in which the inner circumferential portion of plate 1 protrudes from the inner surface 3a. Image of A (however, the shadow caused by the protrusion of plate l is not shown)
are shown respectively.

Assuming that the cylinder A is of good quality, the inner surface 8a in the image of FIG. 3(a) is brightest at the front end 3b and gradually darkens as it approaches the rear end 3c, and its brightness changes. Therefore, the output signal from the sensor 6 appears as a waveform as shown in FIG. 3(b). This waveform signal of Fig. 3 (b) is filtered to the filter 7.
When applied to , a waveform signal as shown in FIG. 3 (c) is obtained. Further, when this waveform signal of FIG. 3(C) is differentiated by the circuit 8, a waveform signal as shown in FIG. 8) is obtained. Furthermore, if the waveform signal shown in Fig. 3) is applied to the filter 9, we get
A waveform signal is obtained by eliminating the rising and falling portions from the signal shown in FIG. 8 (e). Therefore, in circuit 10, circuit 9
The output value and the reference value (area of Sl-82, area of 83 to S4) are compared. At this time, since the output value from the circuit 9 does not exceed the reference value, the output signal from the circuit 1O is zero as shown in FIG. Therefore, the circuit 11 is not activated, and the alarm and warning lamp are not activated.

However, if the cylindrical body A is a defective product as shown in the image of FIG. Disturbance occurs in the change in brightness from the rear end 3c to the rear end 3c. In other words, the output signal from sensor 6 is as shown in Figure 4 (b).
It appears as a waveform like this. When this waveform signal of FIG. 4(b) is applied to the filter 7, a waveform signal as shown in FIG. 4(c) is obtained.

Further, when the waveform signal shown in FIG. 4(c) is differentiated by the circuit 8, a waveform signal as shown in FIG. 4(c) is obtained. Furthermore, when the waveform signal shown in FIG. 4) is filtered by the filter 9, a waveform signal obtained by eliminating the vertical A7, upper, rising, and lower C portions is obtained from the above-mentioned signal), as shown in FIG. 4 (E).

Therefore, in the circuit 10, the output value from the circuit 9 and the reference value (region 81 to S2, region 83 to S4) are compared. At this time, since the output value from the circuit 9 exceeds the reference value, a signal as shown in FIG. 4 is generated from the circuit 10.

Therefore, the circuit 11 is activated, and an alarm or a warning lamp is activated to notify the operator that the inner surface finish of the cylinder A is poor.

The above description is only an example. For example, in a case where the inner circumference of the cylinder A is not necessarily circular and a protrusion is formed only in one part, the cylinder A or the sensor 6 may be moved at a certain angle. It is obvious that the rotational position can be changed by a total of 180 degrees and the same inspection as in the above-mentioned embodiments can be performed at each position. Also, the filter 9 is replaced with a gate circuit, and the 8th.
It is also possible to erase the rising and falling portions from the signals shown in FIGS. 4 and 4). Furthermore, the sensor 6 is a television camera.

A scanning line passing approximately through the center of the cylinder A (for example, the 131st scanning chopstick from the scanning start point) may be scanned, and the video signal may be electrically processed in accordance with the above embodiment. Replacement of other components with equivalents is also included within the technical scope of the present invention.

As described above, the present invention includes the following steps from the front of the cylinder A to the inner surface 3a.
At the same time, the sensor 6 images the inner surface 3a from the rear of the cylinder, electrically detects the degree of disturbance in the change in brightness from the front end 3b to the rear end 8c of the inner surface 3a, and compares the detected value with Since the quality of the finished state of the inner surface 8a is determined by comparing it with a preset reference value, the inspection does not take time and effort unlike the conventional method, and the inspection can be carried out simply and reliably.

[Brief explanation of the drawing]

The figures are all one embodiment of the present invention, and Figure 1 is an explanatory perspective view of a concrete cylinder, Figure 2 is an explanatory overall partial longitudinal view, and Figures 3.4 (A) to (F) respectively. is an action explanatory diagram. In Fig. 8.4, each (a) indicates an image of the image sensor, and each (n) to (f) indicates a signal waveform. In the figure, A...Concrete cylinder, 3a...Inner surface, 8b...Front end, 8c...Rear end, 4...Light projector, 5/I69...Shade plate, 6... - Image sensor, 8... Differential circuit, lO... Comparison circuit, 11... Warning circuit. Applicant ShinMaywa Industries Co., Ltd. Agent Tadashi Bengami (and 1 other person) No. 3 Illustration 4

Claims (1)

[Claims] A light projector for irradiating the cylinder, located in front of the concrete cylinder and approximately coaxially with the cylinder, and a light projector for imaging inside the cylinder, located approximately coaxially with the cylinder at the rear of this projector. a circuit that differentiates the signals from the image sensor and the sensor; a circuit that compares the output value from this differentiation circuit with a preset reference value; and a warning circuit that is activated when the output value of the concrete cylinder exceeds the reference value.