JPH0119101B2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to wooden poles commonly called "utility poles" for supporting power transmission and distribution or communication lines, or trees (these are collectively referred to as "wooden poles" in this specification).
This invention relates to a test device for determining the decay of wood.

Traditionally, the methods used to determine the rot of a wooden pole include directly visualizing the damage after excavation at the base, and determining the sound produced by hitting the wooden pole with a hammer. There were problems with the former, such as internal decay being difficult to detect, and the latter requiring considerable skill. In addition, there are other methods, such as the perforation measurement method based on the length of growth and the sonic transmission method, but these methods are low in accuracy and have many practical problems.

Therefore, recently, a drill-type wooden column rot tester has been proposed.

The purpose of the present invention is to improve this drill-type wooden pole rot tester, and it focuses on the fact that wooden poles have annual rings, and these rings disappear in decayed parts, and the tree ring pattern can be determined from the detection signal. It is an object of the present invention to provide a wooden pole rot tester that can reliably detect rot by detecting the disappearance of wooden poles.

An embodiment of the present invention will be described below with reference to the drawings. In Fig. 1, reference numeral 1 is a drill, and the shaft part except the tip part is tapered to prevent friction between the side wall of the hole drilled by the drill 1 and the shaft part of the drill 1. This is done so as not to adversely affect the measurements described below. This drill 1 is rotationally driven by a rotary drive mechanism 2, and is sent out by a delivery mechanism 3 so that the reaction force (thrust force) applied in the axial direction of the drill 1 during drilling is kept at a constant value. , the tip part penetrates inside the wooden pillar while making a hole in the wooden pillar.
Note that the constant thrust feeding mechanism 3 can be configured by, for example, a moving mechanism employing a ball slide rail and a hydraulic drive mechanism. In order to detect the displacement of the drill 1, a linear potentiometer 4 whose slider moves in conjunction with the advance of the drill 1 is provided.The displacement signal appearing on this slider is differentiated by a capacitor 5, and the speed The signal is sent to a signal processing section consisting of an amplifier circuit 6, a comparator 7, and a period detection circuit 8, where disappearance of the annual ring pattern in the speed signal is detected.
The display or recording circuit 9 is driven. Power is supplied to these circuit sections, the rotational drive mechanism 2 and the delivery mechanism 3 from a battery 10.

Next, the operation of the wooden pole rot tester having the above structure will be explained with reference to FIG. 2. 2A, B, C, and D represent signal waveforms at each point a, b, c, and d in FIG. 1. Drill 1
As the hole is drilled into the inside of the wooden column with a constant thrust force,
There are annual rings inside the wooden pillar, which means that there are layers of relatively hard and relatively soft parts.
The axial direction (advancing direction) displacement signal a of the drill 1 is the second
As shown in Figure A, it changes depending on the annual rings. The differential signal b obtained by differentiating this displacement signal a with respect to time becomes a speed signal as shown in FIG. When you reach the
In the decayed area, the growth rings disappear and there is almost no difference between the hard and soft parts, resulting in a relatively uniform soft part, so the speed increases and exceeds a certain signal level. Therefore, it may be possible to set an appropriate reference level and determine that it is a decayed part when it exceeds this level, but in the present invention, in order to more reliably detect a decayed part, it is possible to detect the disappearance of the signal pattern corresponding to the annual ring. I'm trying to detect it. Therefore, the comparator 7 compares the output signal (speed signal) of the amplifier circuit 6 with the reference level L and shapes the _waveform to obtain a pulse wave as shown in _{FIG . +2} ... is detected by the period detection circuit 8. That is, either the maximum value of the period is determined in advance and it is detected that the period T _i becomes larger than this value, or the period ratio T _{i +1} /T _i is set and the ratio of T _{i +1} /T _i is determined. Detects when the measured value is larger than the set value. In this way, when the signal pattern corresponding to the tree rings disappears, a decayed part detection signal d as shown in FIG. 2D is output and displayed or recorded.

As described above in the embodiments, according to the present invention, wooden pillars have annual rings (multilayered hard and soft parts), and in decaying parts, these are lost and become almost uniform soft parts. Focusing on this, when a drill penetrates with a constant thrust force, its advancing speed takes a pattern according to the annual rings, and this pattern disappears in the decayed area, so the speed signal is processed to eliminate the annual ring pattern. It is judged as a rotten part.
Therefore, extremely accurate determination is possible.

[Brief explanation of drawings]

FIG. 1 is a block diagram of one embodiment of the present invention, and FIG.
Figures A, B, C, and D are time charts showing signal waveforms at points a, b, c, and d in Figure 1. DESCRIPTION OF SYMBOLS 1...Drill, 2...Rotary drive mechanism, 3...Constant thrust delivery mechanism, 4...Linear potentiometer, 5...
Differential capacitor, 6... Amplifying circuit, 7... Comparator, 8... Period detection circuit, 9... Display or recording circuit, 10... Battery.

Claims (1)

[Claims] 1. A drill, a rotational drive mechanism for this drill, a delivery mechanism that sends out the drill with a constant thrust force, a detector that detects the displacement of the drill, and a speed signal that is obtained by differentiating the displacement signal from this detector. A differentiating circuit, a waveform shaping circuit that shapes the output signal of this differentiating circuit to obtain a pulse wave, and detects the period of the pulse wave signal of this waveform shaping circuit and detects the period of the decayed part in response to the increase in the period. A wooden pole decay tester consisting of a periodic detection circuit that generates a detection signal.