JP6153418B2 - Sound stick - Google Patents

Description

  The present invention relates to a sound listening rod for exploring a location to be measured such as a water leakage location, and more particularly to a sound listening rod that reduces reverberant sound and has high sensitivity in low and mid ranges.

  Usually, various leaking sounds are generated from leaking places such as water in buried pipes such as water pipes buried in the ground. As the leakage sound, for example, in the case of a water pipe, a running sound, a water sound, an impact sound, etc. are generated. These leakage sounds become audible sounds peculiar due to the friction between the amount of water or gas to be jetted and the defective portion of the pipe line due to the action of the pressure in the pipe at the leakage point. Such leaking sound (audible sound) propagates in the inner wall of the pipe or the water flowing in the pipe, and reaches a stop cock, a gate valve, a fire hydrant, etc. in the vicinity.

  Therefore, in general, when investigating the presence or absence of water leaks from leak points in underground water pipes, water taps, stop cocks, gate valves, fire hydrants attached to these buried pipes Make a hole in the ground, insert a sounding rod into this borehole, and pierce until the tip reaches the vicinity of the leaked part of the buried pipe. Then, an operator puts his ears on the sound hole opened in the case of the sound bar and listens to the leaked sound propagating through the buried pipe to determine the presence or absence of the leak.

  Here, taking the leakage sound (water leakage sound) of a water pipe buried in the ground as an example, the frequency of the water leakage sound will be described. In the case of a small-diameter resin pipe used for water supply, its strength is relatively low compared to a metal pipe or the like, so the frequency peak of the leaked sound generated at the leak location is in the range of approximately 100 Hz to 350 Hz. is there. Many frequency peaks occur in this frequency range. In addition, in the case of a metal pipe used as a digestive plug, its strength is higher than that of a resin pipe, so that its leaking sound has a relatively higher frequency than that of a resin pipe, and its frequency peak is 400 Hz to It is in the range of 600 Hz. In this frequency range, the occurrence of frequency peaks is less than that of resin pipes. In the case of a large-diameter water pipe, the leakage sound is said to have a frequency of about 800 Hz.

  From the above, it is generally estimated that the frequency of leakage sound is in the range of 100 Hz to 800 Hz. Therefore, in order to listen to the leaked sound accurately, there is a problem of how to improve the sensitivity of the low sound range of 100 Hz to 800 Hz.

  On the other hand, the sensitivity of the human ear is characterized by good sensitivity to the high frequency range of 3 kHz to 5 kHz, but conversely, the sensitivity to the low frequency range of 100 Hz to 800 Hz is poor. Therefore, there is a problem that when the sensitivity in the low sound range is lowered, it is difficult to hear the leaked sound. Furthermore, there is a problem that it is difficult to distinguish between sounds generated in the vicinity, such as underground resonance sounds, hustle sounds, and pseudo sounds, and leakage sounds.

  Also, when drilling a hole in the ground and inserting a listening rod into this hole, and piercing the tip to the vicinity of the leak location to hear the leaking sound, the case of the listening rod during boring (workers Since a large impact load is applied to the part to which the ear is applied, the case of the listening rod requires a mechanical strength that can withstand boring. Therefore, in order to improve the mechanical strength of the case, it is necessary to increase the thickness of the case or to increase the longitudinal strength of the case in order to increase the case depth (vertical length). Become.

  Thus, when the mechanical strength of the case is increased, the weight of the case inevitably increases. However, when the weight of the case is increased, the sensitivity of the leaked sound in the low frequency range of 100 Hz to 800 Hz is lowered, and there is a problem that it becomes difficult to properly detect the leaked sound. For this reason, there has been a problem that the contradictory conditions of the increase in the mechanical strength of the case and the improvement in the sensitivity in the low frequency range must be compatible.

  Therefore, the inventors can accurately determine the leaked sound even when the sensitivity of the low frequency range of the leaked sound propagating from the leaked part is low, and limit the weight of the listening rod. However, an application was previously filed for a sound listening rod that can accurately capture the leakage sound (frequency in the low frequency range) that propagates from the leakage location (Patent Document 1).

  In the invention relating to the sound bar previously filed by the inventors, as shown in FIGS. 10 to 11, the sound bar 121 includes a rod-shaped portion 122 and a housing portion 123. , A rod-shaped body made of a metal such as stainless steel, the distal end portion 122a is sharp, and the base end portion 122b is formed with a male screw portion 122c on the peripheral surface.

  The casing 123 includes a lower casing 124 and an upper casing 125. An insertion hole 124a is formed in the center of the bottom surface of the lower casing 124, and a male screw portion 125b is formed on the upper peripheral surface. Is formed. In addition, the upper housing 125 has a sound hole 125a formed in the center of the upper surface, and a female screw portion 125b formed in the lower peripheral surface. A vibration plate 126 and an O-ring-shaped cushioning material 127 are disposed in the housing portion 123.

  Since it is configured in this way, the distal end portion 122a of the rod-like portion 122 of the listening stick 121 is brought into contact with a water stop cock, a gate valve, a digester plug 172, etc. attached to the buried pipeline, or boring When the rod-shaped portion 122 of the sound-listening rod 121 is inserted into the hole and the distal end portion 122a of the rod-shaped portion 122 is positioned in the vicinity of the buried conduit, the leaking sound propagating through the buried conduit is transferred to the distal end of the rod-shaped portion 122. Propagated from the portion 122a to the base end portion 122b. At this time, the base end portion 122 b of the rod-shaped portion 122 is fixed to the lower housing 124, but the upper end of the base end portion 122 b of the rod-shaped body 122 is separated from the diaphragm 126 and is fixed to the diaphragm 126. Therefore, the vibration propagated to the base end portion 122 b of the rod-like portion 122 is sufficiently propagated to the lower housing 124 and vibrates without being constrained by the diaphragm 126.

  On the other hand, the upper end of the base end portion 122 b of the rod-like portion 122 is separated from the diaphragm 126 and is not fixed to the diaphragm 126, so that the vibration propagated to the lower housing 124 is propagated to the diaphragm 126. The diaphragm 126 vibrates without being constrained so much. Therefore, the vibration sound that propagates to the lower casing 124 and the diaphragm 126 is not reduced, and even if the leakage sound captured by the listening rod 121 is small, leakage occurs in the buried pipe. It is possible to accurately determine whether or not

  On the other hand, the vibration propagating to the base end portion 122b of the rod-shaped portion 122 is sufficiently propagated to the lower casing 124 and the diaphragm 126 vibrates without being restrained so much, so that the resonance frequency of the diaphragm 126 is increased. In order to capture high frequency leakage sound, it is not necessary to reduce the mass of the housing portion 123 and the degree of freedom of the size, shape, material, etc. of the housing portion 123 is increased. The resonance frequency of the plate 126 can be set high, high-frequency leakage sound can be efficiently captured, and it can be accurately determined whether or not leakage has occurred in the buried pipeline.

JP 2012-154651 A

  Thus, the above-mentioned invention filed by the inventors previously has many advantages, and is particularly effective in the high sound range. However, the effect of the low frequency range, which is the main frequency range of leaked sound, is limited compared to the high frequency range. For the low frequency range that is the frequency range of this leaked sound, by taking advantage of the possibility of increasing the degree of freedom of the size, shape, material, etc. of the casing 123, by reducing the size and weight of the casing 123, The sensitivity of the low range can be improved. However, by reducing the size and weight of the casing 123, there is a problem that reverberant sound due to direct waves and reflected waves of the leaked sound is generated and the leaked sound is heard. In addition, when reverberant sound is generated, it is difficult to determine the position of the sound source (where the leaked sound is generated).

  The present invention has been made in view of the above problems, and in order to achieve both the contradictory conditions of improvement in the mechanical strength of the case 3 of the listening stick 1 and improvement in sensitivity to frequencies in the low frequency range, the listening stick 1 Even if the volume of the case 3 is increased, the sensitivity to the frequencies in the low and middle ranges can be improved, and the reverberant sound caused by the downsizing of the case 3 of the listening stick 1 can be suppressed. The purpose is to provide a bar.

  The invention according to claim 1 is composed of a lower case attached to the end portion of the bar, an upper case covering the open end of the lower case, and a bar, and the upper case and the lower case via an O-ring. The disc-shaped diaphragm sandwiched between the two is placed in contact with the point to be measured (leakage point) or close to the measured point (leakage point), and the leaking sound from the point to be measured is captured by the disc-shaped diaphragm. In the listening rod that searches for the presence or absence of leaking sound from the leaking hole from the listening hole that opens in the case, the case has a hole that is opened on the bottom surface of the center portion of the lower case, and a hole through which the end of the bar passes. Auxiliary diaphragm that is attached to the end of the bar protruding from the inside of the lower case and vibrates due to the propagation wave from the leaked sound propagating through the bar, and the vibration of this auxiliary diaphragm is propagated through the gap and the auxiliary vibration In the horizontal direction with the plate And a disk-type diaphragm that is vibrated by a propagation wave from a leaked sound that propagates through the bar through the lower case, and an O-ring that is interposed between the disk-type diaphragm and the upper case. This is a sound listening bar that is arranged and uses a disc-shaped diaphragm together with an auxiliary diaphragm to suppress reverberation generated in the case.

  The invention according to claim 2 is the invention according to claim 1, wherein the auxiliary diaphragm is attached to the end portion of the bar via a bracket.

  The invention according to claim 3 is the invention according to claim 2, wherein the bracket is erected on the cylindrical portion into which the screw portion formed at the end portion of the bar is fitted, and the top portion of the cylindrical portion, and the auxiliary diaphragm is provided. It consists of a support column having means for supporting so as to be parallel to the horizontal direction.

  The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the auxiliary diaphragm is a plurality of tuning fork type diaphragms arranged symmetrically with the end of the bar as the center point. is there.

  Since the invention which concerns on Claim 1 was comprised as mentioned above, generation | occurrence | production of the reverberation sound by size reduction of the case of a sound listening rod can be suppressed. Accordingly, since the leakage sound from the measurement location (leakage location) can be clearly heard, the location of the leakage location can be easily identified. Furthermore, since the sensitivity to frequencies in the low to mid range can be improved, even if the leaked sound is small, the vibration (sound) can be heard properly and the location of the leaked part can be easily identified. . Furthermore, since the auxiliary diaphragm is used, the sensitivity in the low frequency range can be improved even when the case volume is small.

  Furthermore, the generation of reverberant sound due to the miniaturization of the case is suppressed by the auxiliary diaphragm, so that the sound does not wrap around and the leaked sound can be heard clearly. In addition, the disc type diaphragm is not fixed to any part and is in a free state, so it can vibrate without being constrained, and the effect of further amplifying the propagation wave of the leaked sound There is.

  The propagation wave of the leaked sound propagating to the bar, lower case, auxiliary diaphragm, gap, and disk type diaphragm is not attenuated, but rather is amplified and propagated by the auxiliary diaphragm and disk type diaphragm. Even when the leaked sound from the leaked portion is small and the amplitude of the propagation wave is small, it is possible to listen with high sensitivity and to accurately determine whether there is a leaked portion in the buried pipeline. Furthermore, as is apparent from the measurement results shown in FIG. 9, the linearity of the frequency characteristic of the sound listening stick 1 according to the present invention is good, so that it is easy to identify the leaked portion.

  Since the invention according to claim 2 is configured as described above in the invention according to claim 1, the same effect as that of claim 1 can be obtained, and the assembly of the listening rod is facilitated.

  Since the invention according to claim 3 is configured as described above in the invention according to claim 2, the same effect as that of claim 2 can be obtained.

  The invention according to claim 4 can obtain the same effects as those of the inventions according to claims 1 to 3, and can further suppress the occurrence of reverberant sound due to downsizing of the case 3.

1, showing an embodiment of the present invention, is a perspective view of an external appearance of a main part of a sound listening stick 1 according to the present invention. 1, showing an embodiment of the present invention, is an exploded perspective view of a main part of the listening stick 1 shown in FIG. 1, showing an embodiment of the present invention, is an exploded perspective view of a main part of a sound listening stick 1 according to the present invention. 1, showing an embodiment of the present invention, is a cross-sectional view of an essential part of a sound listening stick 1 according to the present invention. BRIEF DESCRIPTION OF THE DRAWINGS It shows the Example of this invention, It is a figure which shows the auxiliary | assistant diaphragm 4 arrange | positioned in the case 3 of the listening stick 1 by this invention, (a) A figure is a top view, (b) A figure is a bottom view, (C) The figure is a side view. BRIEF DESCRIPTION OF THE DRAWINGS It shows the Example of this invention, and is a figure which shows the bracket 11 which attaches the auxiliary diaphragm 4 arrange | positioned in the case 3 of the sound listening stick 1 by this invention, (a) A figure is a top view, (b) figure Is a plan view, and FIG. 6C is a cross-sectional view taken along line AA of FIG. 1, showing an embodiment of the present invention, is an exploded perspective view of a main part of a sound listening stick 1 according to the present invention. 1, showing an embodiment of the present invention, is a block diagram of a main part of a measuring apparatus for measuring the frequency characteristics of a leaked sound captured by a sound listening stick 1 according to the present invention. The Example of this invention is shown and it is a frequency characteristic figure of the leaking sound each capture | acquired by the sound listening stick 1 by this invention, and the conventional sound listening stick 121, respectively. It is a disassembled perspective view of the conventional sound listening stick 121 which shows a prior art example. It shows a conventional example and is a cross-sectional view of a housing portion 123 of a conventional sound listening stick 121.

  A disc-shaped vibration consisting of a lower case attached to the end of the bar, an upper case covering the open end of the lower case, and a bar and sandwiched between the upper case and the lower case via an O-ring With a plate, touch the tip of the bar to the location to be measured (leakage location) or close it to capture the leaked sound from the location to be measured with the disc-shaped diaphragm, and from the listening hole that opens in the upper case In a listening rod for exploring the presence or absence of leaking sound from a leaking part, the case is opened on the bottom of the center of the lower case, and a bar that penetrates through the end of the bar and a bar that protrudes from the hole into the lower case. Auxiliary diaphragm that is attached to the end of the plate and vibrates due to the propagation wave from the leaked sound propagating through the bar, and the vibration of the auxiliary diaphragm propagates through the gap and is parallel to the auxiliary diaphragm in the horizontal direction. Placed and below A disc type diaphragm that vibrates due to a propagation wave from a leaking sound propagating through a bar through a base, and an O-ring interposed between the disc type diaphragm and the upper case, By using the auxiliary diaphragm together with the diaphragm, reverberation sound generated in the case is suppressed. The auxiliary diaphragm is attached to the end portion of the bar via a bracket, and the bracket is erected on the cylindrical portion into which the screw portion formed at the end portion of the bar is fitted, and the top portion of the cylindrical portion. It comprises a support column having means for supporting so as to be parallel to the horizontal direction. Further, the auxiliary diaphragm has a plurality of tuning fork diaphragms arranged symmetrically with the end of the bar as the center point.

An embodiment of the present invention will be described in detail with reference to FIGS.
FIG. 1 is an external perspective view of a main part of a sound listening stick 1 according to the present invention, FIGS. 2 and 3 are exploded perspective views of a main part of the sound listening bar 1 according to the present invention, and FIG. is there. FIGS. 5A and 5B are diagrams showing the auxiliary diaphragm 4 disposed inside the case 3 of the listening stick 1, wherein FIG. 5A is a plan view, FIG. 5B is a bottom view, and FIG. 5C is a side view. . 6A and 6B are views showing a bracket 11 for attaching the auxiliary diaphragm 4 disposed in the case 3 of the listening rod 1 to the bar 2, wherein FIG. 6A is a top view, FIG. 6B is a plan view, c) The figure is the sectional view on the AA line shown to (b) figure. FIG. 7 is an exploded perspective view of the main part of the sound listening stick 1.

  1 to 4, a sound listening stick 1 according to the present invention captures a leaked sound from a leaked portion by a tip 2a of a bar 2, and propagates the captured leaked sound 2 and an end of the bar 2. The case 3 is configured by a case 3 attached to the portion 2b and a vibration mechanism that is disposed inside the case 3 and vibrates due to leakage sound.

  The bar 2 is made of a hard metal such as stainless steel, and the tip 2a of the bar 2 is formed in a sharp shape, and the water stop cock is attached to the buried pipe (not shown). (Not shown), gate valve (not shown), digestive plug (not shown), or the like, or the listening rod 1 is inserted into the borehole, and the tip of the bar 2 until the vicinity of the buried pipe The part 2a is pierced and the leaking sound from the leaking part is captured. A screw portion 2c is formed on the outer periphery of the end portion 2b of the bar 2, and a case 3 in which a vibration mechanism and attachment parts thereof are disposed is attached to the screw portion 2c.

  The case 3 is composed of a lower case 3b attached to the end 2b of the bar 2 and an upper case 3a covering the open end of the lower case 3b, and the inside is formed in a hollow with a lightweight metal such as aluminum. . Inside the case 3, a vibration mechanism such as an auxiliary diaphragm 4, a disk-type diaphragm 5, an O-ring 6, attachment parts thereof, and the like are disposed.

  Further, a male screw portion 3d is formed on the outer periphery of the opening end of the lower case 3b, and a hole 3c through which the end portion 2b of the bar 2 passes is formed on the bottom surface of the center portion of the lower case 3b. The end 2b of the bar 2 protrudes from the hole 3c into the lower case 3b, and a threaded portion 2c is formed at the protruding portion. Accordingly, the lower case 3b is attached to the end portion 2b of the bar 2 by the mounting parts such as the screw part 2c, the nuts 7 and 8, the flat washers 9, 10 and the like. At this time, the screw portion 2c formed at the end portion 2b of the bar 2 protrudes to some extent from the nut 8 in order to fix a bracket 11 to be described later with screws.

  In addition, a sound listening hole 3f is provided at the center of the upper case 3a for listening to a leaked sound by applying an ear, and the male screw portion 3d of the lower case 3b is provided at the inner periphery of the open end of the upper case 3a. A female screw portion 3e is formed to be screwed together. Further, as shown in FIGS. 2 and 4, an O-ring 6 formed of a flexible, durable, water-resistant member such as rubber or plastic is disposed in the upper case 3a. .

  As shown in FIGS. 2 to 4, the disc type diaphragm 5 is a disc type having a diameter substantially equal to the inner diameter of the upper case 3 a, has good vibration propagation properties such as copper, phosphor bronze, stainless steel, etc., and has high hardness. It is made of a highly elastic metal. When the female screw portion 3e formed on the inner periphery of the opening end of the upper case 3a and the male screw portion 3d formed on the outer periphery of the opening end of the lower case 3b are screwed together, the disc-shaped diaphragm 5 is It is sandwiched by the upper case 3a through the open end of the lower case 3b and the O-ring 6, and is not fixed to any part.

  As shown in FIG. 5, the auxiliary diaphragm 4 disposed inside the case 3 has a structure in which tuning fork type diaphragms 4b and 4b are fixed to both ends of the support wire 4a by caulking or soldering. . In this embodiment, a piano wire which is a high carbon wire is used as the support wire 4a. However, a hard steel wire having excellent strength and toughness may be used.

  As shown in FIGS. 6 to 7, the bracket 11 is for attaching and fixing the two auxiliary diaphragms 4 and 4 to the end portion 2b of the bar 2 protruding from the hole 3c of the lower case 3b. The cylindrical part 11a in which the screw part 2c part currently formed in the terminal part 2b of the bar | burr 2 fits is comprised, and the support pillar 11b standingly arranged by the top part of this cylindrical part 11a. The support column 11b has means for supporting the two auxiliary diaphragms 4 and 4 in the horizontal direction. A thread groove (not shown) is formed on the inner peripheral surface of the cylindrical portion 11a so as to be screwed with the threaded portion 2c of the bar 2. Further, in this embodiment, two auxiliary diaphragms 4, As means for supporting 4 in a horizontal direction, the support pillar 11b is formed with two concave grooves 11c perpendicular to each other in a cross shape. The center portion of the support wire 4a is inserted into the concave groove 11c so that the two auxiliary diaphragms 4 and 4 are perpendicular to each other in the horizontal direction and are parallel to each other by adhesive or soldering. It is fixed.

  In this embodiment, a groove 11c is formed in the support column 11b as means for supporting the two auxiliary diaphragms 4 and 4 so as to be orthogonal to each other in the horizontal direction and to be parallel to each other. However, the present invention is not limited to this. For example, the auxiliary diaphragm 4 may be directly fixed to the bracket 11 by an adhesive or soldering.

  When the female screw portion 3e formed on the inner periphery of the opening end of the upper case 3a and the male screw portion 3d formed on the outer periphery of the opening end of the lower case 3b are screwed together, two auxiliary vibrations As shown in FIG. 4, there is a gap 12 between the plates 4 and 4 and the disc-shaped diaphragm 5, and the disc-shaped diaphragm 5 is connected to the open end of the lower case 3b and the O 2. The ring 6 is interposed between the upper case 3a and is not fixed to any part. Accordingly, the vibration from the auxiliary diaphragm 4 is propagated to the disc-shaped diaphragm 5 through the gap 12.

  In this embodiment, two auxiliary diaphragms 4 are used. However, the present invention is not limited to this, and the number of auxiliary diaphragms may be three, four, or more. When a plurality of auxiliary diaphragms are used, the auxiliary diaphragms are arranged so as to be equiangular with respect to the end portion 2b of the bar 2.

  In this embodiment, the two auxiliary diaphragms 4 and 4 are used in combination so as to be perpendicular to each other in the horizontal direction and parallel to each other, and are fixed to the bracket 11. However, the present invention is not limited to this. It is not something. The support wire 4a and the tuning fork diaphragm 4b fixed by caulking or soldering are used so that the tuning fork diaphragm 4b is parallel to each other in the horizontal direction. It is also possible to combine a plurality of ends that are not fixed to form one auxiliary diaphragm 4 and fix it to the bracket 11.

  In this embodiment, the auxiliary diaphragms 4 and 4 are attached to the end portion 2b of the bar 2 via the bracket 11. However, the present invention is not limited to this, and the bar 2 protruding from the lower case 3b is not limited thereto. A concave groove for inserting and fixing the support columns 4a, 4a,... Of the auxiliary diaphragms 4, 4,. In this case, since it is not necessary to use the bracket 11, the number of parts and work processes can be reduced.

Next, the inventors measured the performance of the listening stick 1 according to the present invention as shown in FIGS. FIG. 8 is a principal block diagram of the measuring apparatus, and FIG. 9 shows the measurement results.
In FIG. 8, a signal imitating a leaking sound created by the function generator 20 and the digital counter 21 so that the frequency can be changed is amplified by a PA (power amplifier) 22, and the bar 2 of the listening stick 1 is amplified by a pressurizing vibrator 23. The vibration is added to. At this time, a PU (piezoelectric element) 25 connected to the FFT analyzer 24 is brought into contact with the sound listening hole 3 f, and vibration captured by the sound listening rod 1 is measured by the FFT analyzer 24.

  FIG. 9 is a frequency characteristic diagram of the sound listening stick 1, where the horizontal axis represents frequency and the vertical axis represents output sensitivity (dB). FIG. 9 shows the results when the measurement frequency range is 100 Hz to 1800 Hz. The solid black line shows the result of the listening stick 1 of the present invention, and the gray broken line shows the result of the conventional listening stick. ing. In this performance measurement test, the listening bar 1 of the present invention uses a bar 2 having a length of 1.5 m, and the conventional listening bar is the length of the bar 2 of the listening bar 1 of the present invention. Measurements were made using the same sheath diameter.

  As is clear from the measurement results shown in FIG. 9, the sound listening stick 1 of the present invention generally has high sensitivity in the frequency range of 100 Hz to 1800 Hz as compared with the conventional sound listening stick, and 1500 Hz to It was found that the sensitivity is particularly good in the mid range of the frequency of 1800 Hz.

Next, the assembly and operation of the sound listening rod 1 according to the present invention will be described with reference to FIGS. 2 to 4 and FIGS.
First, a method for assembling the sound listening stick 1 according to the present invention will be described.
A nut 7 such as a mounting part and a flat washer 9 are interposed at the end 2b of the bar 2 and protruded from the hole 3c formed in the bottom surface of the center of the lower case 3b to a required position in the lower case 3b. The lower case 3b is attached to the end portion 2b of the bar 2 by tightening with mounting parts such as the flat washer 10 and the nut 8. On the other hand, the O-ring 6 is fitted into the upper case 3a along its inner periphery.

  Next, the bracket 11 is screwed and fixed to the screw portion 2c of the end portion 2b of the bar 2 protruding from the nut 8 of the mounting part in the lower case 3b, and then the support lines 4a of the two auxiliary diaphragms 4 and 4 are fixed. The center of 4a is positioned, and it inserts in the ditch | groove 11c currently each formed in the cross shape, and fixes. At this time, the two auxiliary diaphragms 4 and 4 are positioned so as to be orthogonal to and parallel to each other in the horizontal direction. In addition, before fixing the bracket 11 to the screw portion 3c, the support pillars 4a and 4a of the auxiliary diaphragms 4 and 4 may be inserted and fixed in the recessed grooves 11c of the bracket 11, respectively. Workability is improved and fine adjustment of the width of the gap 12 is easy, and the adjustment of the sound listening stick 1 is easy.

  Next, the disc-shaped diaphragm 5 is placed on the opening end of the lower case 3b, and the female screw portion 3e formed on the inner periphery of the opening end of the upper case 3a and the outer periphery of the opening end of the lower case 3b. When the male screw part 3d is screwed together and the open end of the lower case 3b is covered with the upper case 3a, the case 3 is assembled, and the listening rod 1 is completed. In this state, as described above, the disc-shaped diaphragm 5 is sandwiched by the upper case 3a with the opening end of the lower case 3b and the O-ring 6 interposed therebetween, and at any location. It is not fixed and is in a free state.

Next, the operation of the sound listening stick 1 according to the present invention will be described.
Since the sound listening stick 1 according to the present invention is configured as described above, the front end portion 2a of the bar 2 is brought into contact with a water stop cock, a gate valve, a digestive stopper, etc. attached to the buried pipeline, Alternatively, if the acoustic stick 1 is inserted into the borehole and the tip 2a of the bar 2 is pierced and positioned to the vicinity of the buried pipe, the leakage sound from the leaking point propagating through the buried pipe will be Propagated from the tip 3 a to the end 3 b of the bar 3. Next, the propagation wave of the leaking sound is propagated to the auxiliary diaphragm 4 to vibrate the auxiliary diaphragm 4.

  At this time, in this embodiment, since the tuning fork type diaphragms 4b, 4b,... Are used as the auxiliary diaphragms 4, 4, there is an effect of amplifying the propagation wave of the leaked sound, and the volume of the case 3 is small. Even in this case, the sensitivity of the low frequency range can be improved. Furthermore, the generation of reverberant sound due to the downsizing of the case 3 is suppressed by the auxiliary diaphragm 4 so that the sound does not wrap around and the leaked sound can be heard clearly.

  Next, the vibration (propagation wave) of the auxiliary diaphragms 4 and 4 propagates through the gap 12 and propagates to the disc-shaped diaphragm 5, improving the sensitivity of the low frequency range and suppressing the reverberant sound. It is possible to hear the leakage sound from the leakage point clearly by putting the ear on the sound listening hole 3f. At this time, the disc-shaped diaphragm 5 is not fixed to any part and is in a free state, so that it can vibrate without being constrained, Further, it has an amplifying effect.

  Therefore, the propagation wave of the leaking sound propagating to the bar 2, the lower case 3b, the auxiliary diaphragm 4, the gap 12, and the disk type diaphragm 5 is not attenuated, but rather is rather attenuated, and the auxiliary diaphragm 4 and the disk type diaphragm. 5 is amplified and propagated, so that the sound leaked from the leaked portion is small, that is, even when the amplitude of the propagation wave is small, it is possible to listen with high sensitivity and whether there is a leaked portion in the buried portion. Can be accurately determined. Furthermore, as is clear from the measurement results shown in FIG. 9, since the linearity of the frequency characteristic of the sound listening stick 1 according to the present invention is good, the sense of localization is increased and the location of the leakage is easily identified.

  The sound listening stick according to the present invention can be widely used not only for leaking water but also for identifying the source of sound transmitted from the ground, pipes through which fluid flows, buildings, and the like.

DESCRIPTION OF SYMBOLS 1 Sound listening rod 2 Bar 2b Bar end 3 Case 3a Upper case 3b Lower case 3c Hole 3f Sound listening hole 4 Auxiliary diaphragm 4b Tuning fork type diaphragm 5 Disc type diaphragm 6 O ring 11 Bracket 11a Cylindrical part 11b Support Pillar 12 gap

Claims (4)

A circle composed of a lower case attached to the end of the bar, an upper case covering the open end of the lower case, and the bar, and a circle sandwiched between the upper case and the lower case via an O-ring A plate-shaped diaphragm, and the top end of the bar is brought into contact with a measured location (leakage location) or is brought close to the leakage sound from the measured location to be captured by the disc-shaped diaphragm; In the sound listening rod for exploring the presence or absence of leakage sound from the leakage point through the sound hole opening in the
The case is installed on the bottom surface of the central portion of the lower case and is attached to the hole through which the end of the bar penetrates and the end of the bar protruding from the hole into the lower case, and propagates through the bar. An auxiliary diaphragm that vibrates due to a propagation wave from the leaked sound, and the vibration of the auxiliary diaphragm propagates through a gap, and is arranged in parallel with the auxiliary diaphragm in the horizontal direction, and the A disc type diaphragm that vibrates due to a propagation wave from a leaking sound propagating through the bar, and the O-ring interposed between the disc type diaphragm and the upper case,
A sounding stick characterized in that reverberant sound generated in the case is suppressed by using the auxiliary diaphragm together with the disc-shaped diaphragm. The sound listening bar according to claim 1, wherein the auxiliary diaphragm is attached to an end portion of the bar via a bracket. The bracket has a cylindrical portion into which a screw portion formed at an end portion of the bar is fitted, and a means that stands on the top of the cylindrical portion and supports the auxiliary diaphragm so as to be parallel to the horizontal direction. The listening rod according to claim 2, comprising a support column. 4. The acoustic listening bar according to claim 1, wherein the auxiliary diaphragm is configured by arranging a plurality of tuning fork type diaphragms symmetrically with the end portion of the bar as a center point. 5.

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