Echo annexation device

The present invention is related to devices for annexing an echo resembling natural reverberation in the course of sound recording, in which a line or lines of coil spring with a portion or portions protruded axially at a right angle are spanned between the drive-transducer and the pickup-transducer.

BACKGROUND OF THE INVENTION 
The present invention falls into the field of echo annexation devices which 
use coil springs as materials for a signal retardation device. 
Generally, in the echo annexation device, the mechanical vibration 
impressed on a coil spring by the drive-transducer is helically 
transmitted along the coil spring, namely, along the helical direction, 
and concurrently the vibration causes the retardation in time at both ends 
of the coil spring by repeating intermittently the reflection. 
Consequently, the retardation said in time generates the echo. 
The intermittently repeating reflex movement induces the inherent 
compressive movement of the coil spring and results in casing the 
stationary wave, which modulates the echo vibration modulated, and causes 
flutter sound on the part of the pickup-transducer. Therein the frequency 
characteristics are marred so much that distortion develops. 
To prevent this distortion, various devices have been presented. So far, 
some devices have two kinds of coil springs different in helical 
direction, and other devices have a portion having a different coil pitch 
on the coil spring, but none of them has succeeded in preventing this 
distortion. 
SUMMARY OF THE INVENTION 
The primary object of the provide an invention is to present echo 
annexation device which functions to completely prevent flutter modulation 
by having the reflection movement which is generated axially at both ends 
suppressed with a suppressive movement of the coil spring which is spanned 
between the drive-transducer and the pickup-transducer by having a portion 
of the coil spring protrude axially at approximately a right angle to the 
spring. 
The second object of the present invention is to provide an echo annexation 
device which can handle the of complex frequency made of different 
retardation in time by having two portions of the coil spring between the 
drive-transducer and the pickup-transducer providing axially at a right 
angle to the spring., and further by providing a coil spring between the 
two protrusions as of a by-pass. 
The third object of the present invention is to have a remnant time in each 
frequency band of low, medium, and high pitched sound made uniform by 
having a portion of the coil spring between the drive-transducer and the 
pickup-transducer protrude erected axially at approximately a right angle 
as well as having the tip of the said protrusion bent in an optional 
direction or looped several times. Also, the portion is made to function 
as a reflecting point for helically transmitting the vibration for the 
purpose of obtaining an echo. Herewith an echo annexation device is also 
presented which is also capable, with use of only one line of coil spring, 
of the same excellent echo effect achieved when plural lines of coil 
spring are used. 
Other objects and advantages of the invention will become apparent during 
the following discussion of the accompanying drawings wherein:

DESCRIPTION OF THE EMBODIMENT 
The detailed description of the present invention is given according to the 
figures annexed. 
In FIG. 1, 1 is the drive-transducer, 2 is the pickup-transducer, 3 is the 
coil spring spanned between both 1 and 2 transducers, 4 is a portion 
midway of the said coil spring 3, and protrudes from the spring 3. Said 
protrusion 4 is longer than the normal diameter of the coil of the coil 
spring and protrudes axially at approximately a right angle. Also, the 
protrusion 4 is uniformly shaped approximately in the form of an arch so 
that the helical direction of the coil spring 3 is in series. 
FIG. 2 shows two protrusions 4 4, that is, a first protrusion 4 protruding 
in approximately an arched form as mentioned above, so that the helical 
direction of the coil spring 3 is in series. Concurrently at the right 
side position of the same figure, the helical direction is not in series 
as mentioned above, and the second protrusion 4 is approximately in the 
form of letter Omega .OMEGA. and is axially straight when viewed from 
above. 
As mentioned above, one or plural protrusions 4 at any portion of the coil 
spring 3 spanned between the drive-transducer and the pickup-transducer 
can completely suppress the axially directed reflection generated with the 
suppressing movement induced by the repeating reflection at both ends of 
the coil spring 3. 
Consequently, the flutter modulation is completely prevented. This means 
that the protrusions 4 4 protruding axially at approximately right angles 
at any portion of the the coil spring result in increasing the elastic 
flexibility in proportion to the protruding length of the portions. This 
makes it possible to expect more elastic flexibility than is available 
with other helical portions of the coil spring 3. Thus, the suppressing 
movement induced by the repetition of vibration transmission in the 
helical direction to obtain an echo effect can be completely absorbed by 
the elastic flexibility at the protrusion 4, and the elastic flexibility 
makes it possible to completely suppress the flutter modulation. 
FIG. 3 shows two protrusions 4 4 on the coil spring 3 as shown in the 
embodiment of FIG. 2, and also shows a bypass 6 between the said 
protrusions 4 4. In FIG. 3, at the left side of the coil spring 3, the 
first protrusion 4 protruding axially at approximately right angle is 
formed in a stanchion shape and is helically in series. At the right 
side of the coil spring 3, a second protrusion 4 protruded axially 
approximately coaxially with the coil spring when viewed from above, 
without being helically in series. Finally, and a by-pass 6 of coil spring 
6, which is dissimilar in helical diameter and material to the base coil 
spring 3 is spanned between the two tips of of the protrusions 4 4. 
In FIG. 4 a by-pass is shown similar to that shown in the embodiment made 
from the embodiment shown in both FIG. 13 and FIG. 14 as shown below. In 
the embodiments of FIG. 13 and FIG. 14 a special portion 7 is looped once 
on the tip of the protrusion 4; however in FIG. 4, several looped portions 
7 are connected in series. Furthermore, a coil spring 6 is spanned between 
both ends of the protrusion 4 and this spring 6 has a helical diameter and 
material property different than coil spring 3 and the special portion 7. 
Also, a line of thread 8 is provided fixing the protrusion 4. Thus, a 
device which has a protrusion 4 fixed at two positions on the coil spring 
3 and has a coil spring 6 is spanned as the by-pass between the ends of 
the protrusion 4, as shown in FIG. 3 and FIG. 4, can completely suppress, 
at at protrusion 4, the reflection axially generated by the compressive 
movement induced by repeating reflections at both ends of the coil spring 
3. Flutter modulation can thus be naturally prevented, and in addition to 
these functions, complex reflection routes in which retardation time is 
different are be obtained in this embodiment. The device make it possible 
to evade the resonance point. 
FIG. 5 shows an applied example of the embodiment shown in the above 
mentioned FIG. 4. As shown in FIG. 4, the protrusion 4 provided with the 
special looped portion 7 is made by having many numbers of succeeding 
loops. In FIG. 5, these loops are presented in parallel, above and below, 
and a pair of such looped structures is provided in succession. 
In FIG. 6, the protrusion 4 having the special looped protion 7 is made by 
having many numbers of loops as mentioned above and there are again two 
series of parallel loops, is drawn by two in parallel above and below. One 
end of the protrusion 4 is directly connected to the pickup-transducer 2. 
With such a structure, a flutter modulation can be attained as effective 
as that mentioned in the above, and also, a complex route of reflection 
can be obtained. 
In both FIG. 7 and FIG. 8 the protrusion 4 is formed in an arch shape in 
the midway portion of the coil spring 3 spanned between the 
drive-transducer and the pickup-transducer 2. The diameter at the arch is 
larger than that of the coil spring 3 and the helical direction is 
similarly succeeded and bent by bending the arch 6 of the protrusion 4 
slantingly downward. 
In both FIG. 9 and FIG. 10, the stanchion shaped () protrusion 4 protrudes 
axially at approximately a right angle and is axially aligned with the 
spring 3 when viewed from above. It is furtherbent in a U-shape on the tip 
5 of the protrusion 4. 
In both FIG. 11 and FIG. 12, as above, the protrusion 4 in stanchion form 
is axially aligned with the spring 3 and is also bent in a V-form on the 
tip 5 thereof. Thus the protrusion 4 looks like a letter M' on the whole. 
By bending the tip 5 of the protrusion 4, as well as by structuring the 
device as shown in FIG. 1 and FIG. 2, not only can the compressive 
movement induced by the repetition of the reflection at both ends of coil 
spring 3 be completely absorbed, but also, in this embodiment each 
frequency band in low, medium, and high pitch sound can also be functioned 
with approximately the same remnant time. Consequently, reverberation more 
nearly resembling natural reverberation is achieved. 
Flutter sound can be prevented by the protrusion 4 provided at an optional 
position along the coil spring 3 as mentioned above, but it is necessary 
to have the portion of the protrusion 4 comparatively longer 
(approximately three times as long as the length of three coils of the 
coil spring 3. If the length of the protrusion 4 is made longer, the 
flutter sound can be completely prevented. However, the vibration moment 
in the helical direction to achieve reverberation will increase in 
proportion to this effect. The increase in a said vibration moment induces 
the resonance in the said portion, and the secondary problem of increasing 
only the remnant time of the low pitch sound from 80 Hz/Sec. to 700 
Hz./Sec. is developed. 
In the present embodiment, however, by bending the tip 5 of the protrusion 
4, generation of a large vibration moment in the helical direction and 
resonance movement in the said portion can be prevented. Consequently, the 
increase of only the remnant time in low pitch sound is not developed, and 
the remnant time in each frequency band of low, medium, and high pitch 
sound is uniformly generated. When the tip the tip 5 of the protrusion 4 
formed in succession will said protrusion is suppressed all the time in 
the direction of suppression because each base portion of the said 
protrusions 4 is pulled in two directions at both ends by the coil spring 
3, wherein its action in the direction of the elongation is restricted, 
its elasticity becomes less than the other coiled portion. Thus, it is for 
this portion to function as the reflection point of vibration transmission 
in the helical direction and it is possible to attain the various 
retardation timed complex vibration phenomena. This prevents the emanation 
of metallic shrieky sounds as well as makes it possible to get just as 
excellent a frequency characteristic with a single line of coil spring 3 
as is possible when many lines of coil spring were employed. 
In FIGS. 13, 14, 15, and 16 the proteiform embodiments of the above said 
embodiment are shown. 
In both FIG. 13 and FIG. 14, the arch shape protrusion 4, which is larger 
than the coil diameter of the coil spring 3 and has its helical direction 
succeeded in series, has its tip looped once in the same helical direction 
as the coil spring 3 forming the loop 7. 
As mentioned above, the loop 7 can be made in plural numbers. If loop 7 is 
formed by looping, once, the tip of the protrusion 4 so that it intersects 
at approximately a right angle to the helical direction of the coil spring 
3. By forming the loop in this way, the same action as shown in the 
embodiment of FIG. 7 or FI. 12 can be obtained, i.e. the remnant sound 
obtained in this way is closer to the natural remnant sound, and it is 
possible to obtain remnant sound closer to that heard in the concert hall.