close

Вход

Забыли?

вход по аккаунту

?

код для вставки
Jan. 14, 1947.
_
N. T. voLsK
2,414,129
VARIABLE SENSITIVITY SOUND-POWERED RECEIVER
Filed March 5, 1945
.32 WW.
INVENTOR.
NICHOLAS
T VOLSK
ATTORNEY .
Patented Jan. 14, 1947
2,414,129
UNITED STATES PATENT OFFICE
2,414,129
VARIABLE SENSITIVITY SOUND-POWERED
RECEIVER
Nicholas T.Vo1sk, Spring Lake, ‘N. J.
Application March 5, 1945, Serial No. 581,017
6 Claims.
(01. 179_s1)
(Granted under the act of March 3, 1883, as
amended April 30, 1928; 370 0. G. 757)
The invention described herein may be manu
factured and used by or for the Government for
governmental purposes, without the payment to
me of any royalty thereon.
This invention relates to sound-powered re
ceivers, and particularly to a method and appa
ratus for varying their sensitivity which is often
desirable when receivers of this type become con
nected to the telephone lines of different lengths.
It is well-known in the art that the sensitivity
of the sound-powered receivers is superior to the
sensitivity of the receivers of standard type, and,
therefore, it is desirable to use the sound-powered
receivers for extending the range of telephone
communications. However, when receivers of
this type become connected to the lines of rela
tively short length, the intensity of the signal
impressed upon them is so high that the output
of the receiver becomes too loud, and in extreme
cases the receiver becomes over-loaded to such
an extent that its articulation quality is impaired
and the speech becomes unintelligible.
It is also known in the art to adjust the sensi
tivity of the sound-powered receivers by varying
the impedance of the receiver’s circuit (U. S.
Patent 2,344,338), this mode of adjusting the
sensitivity of the receiver being accomplished by
tapping the coil of the receiver, or inserting a
series or shunt resistance in the circuit of the
coil, and by equipping the handset with a switch
which selects the desired sensitivity of the re
ceiver, depending upon the line conditions. This
type of sound-powered receiver is known in the
art as the “dual sensitivity receiver.” The. dual
sensitivity receivers do not accomplish the de
sired results for several reasons.
As the term
itself suggests, they have only two states of sensi
tivity which may be selected by the user by oper
ating the two-position switch, and, as a conse
quence, cannot be adjusted to the optimum sen
sitivity when connected to the lines the imped
ance of which differs from the impedance of those
two lines which can give optimum results at the
2
coil, tapping of the coil is a very di?icult opera
tion. Moreover, even if such costly procedure
were resorted to, a plurality of taps would call
for a multiposition switch which would unduly
complicate the structure, and increase the cost
of the handset. Another serious disadvantage of
any method now used in the art, which all resort
to some method of varying the impedance of the
receiver circuit, resides in the fact that any large
change in the impedance of the receiver is un
desirable from a system point of view. Thus,
when the sensitivity of the receiver is varied by
varying the number of turns included in the cir
cuit, with 540 turns included in the circuit for
high sensitivity and 77 for low sensitivity, there
is a corresponding impedance change in the order
of 50 to 1. The low impedance of the receiver
when the latter is switched to the low sensitivity
position will act as a short-circuiting device for
all other receivers in a conference circuit con
nected to a short line; this is obviously inherently
unsound and should be avoided by devising a
sensitivity adjustment which would maintain the
impedance of the receiver constant throughout
its sensitivity range. Moreover, switching ar
rangements require additional wiring, periodic
inspection and maintenance, and in some in
stances redesigning of handset’s handle which
raises the total cost of the set and creates multi
plicity of standard parts.
The invention avoid-s these di?iculties by pro
viding a lower reluctance path—when needed
for the ?ux produced by the permanent magnet
of the sound-powered receiver, by means of a
variable magnetic shunt which is capable of vary
ing the reluctance of the magnetic circuit be
tween the desired limits in a continuous manner.
Accordingly, the adjustment of the sensitivity of
the receiver is of the continuous type, and these
limits may be arranged so as to shunt completely
the air gap of the receiver (for all practical pur
poses), or to remove the shunting action alto
gether.
The position of the magnetic shunt is
maximum and minimum sensitivities that are
selected so as to have no e?ect on the impedance
made available in the receiver. The crudeness 45 of the receiver itself, and, therefore, the imped
of the available adjustments may be appreciated
more fully when one considers the fact that in
one receiver of this type, which resorts to the use
of the tapped coil in the receiver, the number of
e?ective turns in the low sensitivity position of
the switch is in the order of seventy-seven turns,
while in the high sensitivity position it is in the
order of 540 turns. No continuous adjustment
of the sensitivity of the receiver is possible since,
because of the minute dimensions of the receiver’s
ance relationship between the outgoing imped
ance and the receiver remains undisturbed. As
a matter of fact, there is a slight impedance com
pensation because of the favorable action of the
magnetic shunt on the variable motional imped
ance. However, the value of the motional im
pedance per se is so insigni?cant as compared to
the other impedances involved that from the
point of .view of practical considerations it is
proper to disregard it.
2,414,129
3
4
the sensitivity control knob attached in the cas
ing as illustrated in the ?gure, and
Figure 9 is the schematic diagram of a sub
In placing the magnetic shunt in the structure
of the sound-powered receiver, a caution must be
exercised to place it so that it is preferably re
station circuitwhich may be used in connection
with the sound-powered receivers disclosed in the
moved from the permanent magnet to avoid per
manent Side-demagnetization, orreorientation of
the magnetization‘ of the permanent magnet,
which obviously leads to the permanent loss of
Figs. 1 through 8.
Referring to Fig. 1, it illustrates a well-known
sound-powered
receiver, which includes the
?ux in the main working magnetic circuit of
modi?cations proposed by the principal inven
the permanent magnet.
The shunting action of the magnetic shunt 10 tion, A permanent magnet Ill is mounted be
tween a ferromagnetic disc l2 and a ferromag
from a purely mechanical point of view may be
netic plate Ill, the three being held together by
accomplished by means of a movable metallic
means of bolts it; similar mechanical coupling
plate made of ferromagnetic material, the posi-'
between plate i4 and disc i2 is provided on the
other'side by a nonmagnetic spacer iii. The non
magnetic spacer is attached to disc l2 and plate
ill, by set screws !3 and i5 on top, and similar
set screws ‘on the bottom, the bottom screws being
not visible in the figures. Two U-shaped ferro
tion of this plate with respect to the magnetic
circuit of the receiver, and especially its air gaps,
being adjusted by means of a shaft, thumb screw,
a push lever, a cam or any other well-known
mechanical movements which have. a control
knob protruding from the case of the receiver,
this knob being operated by a ?nger of the user 20 magneticmembers f2!] and 22 are securely at
tached to plate 51 and disc l2 respectively by
of the set. .,
set screws i? and [9, the bottom set screws being
.It is, therefore, an object of this invention to
not visible in the ?gures. The U-shaped mem
provide a sound-powered receiver with con
bers are so proportioned as to form two slit-like
tinuously variable sensitivity.
It is another object of the invention to provide
a sound-poweredHreceiver, the sensitivity ‘,of
25 air gaps “24 and 25 between them, the view of
the left air gap 25 in Fig. 1 being partially ob
literated by a shaft 26 which is connected to a
ferromagnetic plate 28 through a cam block 33.
which can be varied with substantially no change
in the impedance relationships of the circuits of
Only the right portion of an armature 32 is
which said receiver is a part.v
It is another object of this invention to provide 30 visible in Fig. 1, this end of the armature being
attached to a connecting rod 3% which connects
a sound-powered receiver with continuously
the armature with a'corrugate'd diaphragm 36
variable sensitivity with the parameters of the
of the receiver. The rod is ?xed to the arma
substation circuit remaining substantially con
ture by means of two nuts 38 and 40 on one side
stant, ‘irrespective of the state of sensitivity im
parted to it.
, _
and to the diaphragm by a riveted or welded con
.
It is still another object of this invention to
provide a sound-powered receiver, the sensitivity
of which may be controlled ‘continuously from
maximum to'minimu‘m sensitivity by‘means of a
magnetic shunt included in the magnetic circuit 40
of the receiver.
v
Still another object of this invention is to pro
vide .a sound-powered receiver, the sensitivity of
which'may be controlled with the parameters of
the substation circuit remaining constant, thus
allowing the line circuit to perform its function
faithfully irrespective of the sensitivity setting
of the receiver.
_
'
The novel features which are believed to be
characteristic ofthisinvention are set forth with
particularity in thea‘ppende'd, claims. The in
véntion itself, however, both as to its organiza
nection 42 on the other side. The armature
represents a flat leaf made of ferromagnetic ma
terial which is centrally positioned in the air
gaps formed‘by the U-shaped members, and is
attached on its left side by a set screw 44 to the
nonmagnetic spacerw N3, the upper portion of
which is U-shaped for facilitating this connec
tion. The sound-coil of the receiver is wound
on a bakelite frame 46, this frame being so di
mensioned that ‘it forms a sliding ?t with the U
shaped members 2!! and 22. The turns of the
wire wound on frame'48 are not visible in Figure 1
since their View is obliterated completely by mag
netic shunt plate 28, but they are visible at 55
in Fig. 5. The two terminals of the coil are illus
trated in Fig. 2' at E3 and 59; these are connected
across ‘the anti-side-tone portion ‘of the substa
tion circuit. ,_
_
tion and method of'operation, together with the
The functioning. of the sound-powered receiver
further objects and advantages thereof, may best
be understood by reference to the following de 55 illustrated in the Figs. v1, 2 and 3 is very well
known in the art'and will be mentioned brie?y
scription in, connection with the accompanying
here only to coordinate the functioning of the
drawing in. which:
_,
V
,
r
_
_ "Figure ‘1 is a side elevational view of a sound
magnetic shunt and’ ‘of the receiver. When
varying direct current is impressed on sound
coil 58, of the ‘receiver, it produces a compara
60 tively strong ?ux through the center of the coil,
Figure. 2 is a. verticalv cross-sectional view of
and since the armature of ‘the receiver is posi
the receiver of Fig. '1 taken along'line 2-2;
tioned in the center ‘of the coil the state of its
Figure 3 is a'plan view of the receiver illus~
powered receiver provided with a magnetic
shunt;
.
trated'in Fig. 1.;
.
V.
,
.
'
‘
_
magnetism will ‘follow thestate of flux existing
Since at the air gaps
_,
, lFigure ll'is'aside elevational view of 'a modi?ed 65 in the center'of the coil.
formof the magnetic shunt;
'Figure‘5 isthe‘side‘view'taken along line E-~5
the armature is in a strong magnetic ?eld created
by thepermanent'magnet, the armature will be
either attracted, or ‘repelled ‘by the, U-shaped
magnets‘thus transmuting the electrical undu
similar. to that'illustrated in Figure 1 with a 70 lations into mechanical vibrations which are
transmitted to, diaphragm '36 of the receiver.
modi?ed , mechanical linkage;
ofr'ther'magnetic shunt illustrated in Fig. 4;
v Figure ofisa. side View of a magnetic shunt
, 'Figure 'Iis a top‘plan view ‘of the ‘mechanical
linkagein Fig. 6;.
, U.
.
Figure 8 is a perspective viewof thedu‘al sensi
tivity receiver mounted in a‘handset “c'asi'ng'with
Since one of the'factors controlling the'sensi
tivity of the receiver is the ‘density of the per
manent ?ux in the fair gapsf'the 7sensitivity of
the receiver'may'be ‘controlled by decreasing‘ this
2,414,129
5
density to any desired lower value. If the mag
netic shunt is positioned properly with respect to
thelpermanent magnet as well as the sound coil,
it-will have no permanent demagnetizing effect
6
manner, and assembling of the magnetic shunt
is accomplished by slipping cam 52 into the hole
in block 30, and by force-?tting shaft 54 into
the hole in the cam. The receiver is then
mounted in the Bakelite casing and the casing
is ?tted into the outer shell 862 provided with
coil of the receiver. With the magnetic shunt
a small opening for shaft 26. Shaft26 is in
thus positioned in the receiver, the impedance
serted into the hole and screwed tightly against
looking into the substation circuit will not be af
the inner portion 54 of the shaft until it forms
fected by any adjustment of magnetic shunt and, 10 a tight joint 56 with the latter, which completes
as a consequence, the functioning of the line
assembling of the receiver.
circuit and the state of the properly adjusted
Figs. 4 and 5 illustrate a modi?ed mounting
impedances in the substation circuit remains un
of shunt 400; the cam block 30 in this case is
affected by any adjustment of the sensitivity of
connected to that portion of the shunt which
the receiver.
7
is to the right of plate 62. Either in the Figs.
This is accomplished in Fig. l by placing mag
1 to_3 inclusive or 4 and 5 any sudden shock im
netic shunt-plate 28 adjacent to the U-shaped
parted to the external knob 800, which is in
members 20 and 22, this shunt providing a low
cidentally mounted in a favorable position on
reluctance path for the flux produced by the per
the curved surface of the shell, will not be trans
manent magnet when the magnetic shunt is
mitted to the sensitive parts of the receiver but
moved into the position illustrated in the Figs. 2
will be stopped by the engagement of knob 800
and 3 where it makes direct contact-with its up
against the casing, since cam 52 is free to slide
per portion-with plate I 4 and member 26, and——
laterally in the cam block 30.
with its lower portion—-with member 22 and disc
Figs. 6 and 7 illustrate a modi?ed linkage
I 2. In this position the magnetic shunt produces
mechanism which may be used between the mag
on the permanent magnet, nor will it have any
signi?cant e?ect on the impedance of the sound
magnetic short circuit across the air gaps of the
netic shunt 28 and shaft 54.
receiver and, therefore by far the largest part
of the flux generated by the permanent magnet
ID will follow the path of least resistance, which
is obviously the magnetic shunt 28. When this
wire ‘I00 bent so as to form a wedge-like surface
It consists of a
magnetic shunt will be desirable only when it is
necessary to protect the receiver from high level
sounds, such as gunfire. The sensitivity of the
with respect to the shunt, and the shunt itself
is provided with an eye ‘I02. It is apparent from
the examination of Fig. 7 that the sliding move
ment of shaft 54, as indicated by the arrows,
‘will result in shifting the magnetic shunt toward
or away from the magnetic plate l4, thus pro
ducing the same ?nal result as shunt 28 in the
Figs. 1 to 3 inclusive. In the embodiment illus
receiver may be adjusted by varying the lengths
trated in the Figs. 6 and 7, shunt 28 should form
of the air gaps so as to obtain the desired re
a sliding ?t with the bottom magnetic disc l2
so that there is a continuous magnetic short
is the case, the sensitivity of the receiver is re
duced practically to zero; such position of the
luctance ratio between the working magnetic
circuit of the receiver and the parasitic mag
netic path provided by the magnetic shunt.
Since mechanical movements are available which
circuit between the shunt plate 28 and the disc.
In all arrangements the extensions 60 and 62
are provided with the guiding surfaces prevent
ing tilting of the shunt.
Referring now to Fig. 9, it discloses one type
can change the position of the magnetic shunt
with respect to the main magnetic circuit with
any desired degree of precision, it is possible to
of substation circuit which may be used in con
provide smooth and continuous control of the 45 nection with the sound-powered receiver. The
sensitivity of the receiver between the available
circuit disclosed in Fig. 9 is widely known in
limits.
the U. S. telephone industry as U. S. Army Tele
The mechanical control illustrated in the
phone Set EE-S, and, therefore, requires no de
Figs. 1, Z‘and 3 consists of a cam assembly in
tailed description. It is included in the dis
cluding a cam block 30 provided with a circular 50 closure to emphasize some of the impedance re
hole and a cam 52, Fig. 3, forming a sliding ?t
lationships, the maintenance of which is very de
with the hole. The cam itself is mounted on a
sirable, if not imperative, when the sensitivity of
shaft 54, connected through a threaded engage
the receiver is varied between its maximum and
ment 56 to the external shaft 26. Shaft 26 ex
minimum limits. The sub-station circuit in
tends outwardly through all the casings of the re 55 cludes a hand generator 909, which is used for
ceiver and of the handset where it terminates in
ringing purposes, whose cranking handle is
a knurled knob 80!] mounted adjacent to the outer
coupled through a cam to an armature 902, so
surface of the receiver’s casing 802. By turning
as to transfer this armature to a contact 994
knob B00 either in one direction or the other
at the beginning of the ringing operation by the
the sensitivity of the receiver may be either de 60 local operator. Armature 902 normally rests on
creased or increased until the optimum degree
contact 906 which is connected to a ringer 908,
of transmutation is obtained with the line con
the circuit of which is completed through a con
ditions prevailing at any given moment. The
denser 9l0. The outgoing telephone line con
maximum sensitivity of the receiver is obtained
ductors M2 and 914 are connected across a con
when the magnetic shunt is in the extreme upper 65 ventional induction coil of the sub-station circuit
left position with respect to the main magnetic
which includes three windings 9l6,49|8 and 920,
the upper winding being connected to the out
circuit, as illustrated by the dotted lines in Fig.
3, the minimum sensitivity being obviously that
going line conductor 9l2, while the lower wind
ing 920 is connected to the outgoing conductor
illustrated by the solid lines in the same ?gure.
It is to be noted that frame 46 of the sound 70 9l4 through condensers 922 and 924. A carbon
type transmitter $26 is connected across the pri
coil 50 extends outwardly at 6B and 62 on the
mary winding 918 of the induction coil through
side adjacent to the magnetic shunt extensions
a local source of potential 928 and a handset
60 and B2 are used as bearing surfaces for shaft
switch 930, thus forming a local battery sub
54.
>
The receiver is assembled in a conventional 75 station circuit. The sound-powered receiver is
2,414,129
7
called throughout this speci?cation as the sound
powered receiver. This terminology has been
selected since it is obvious that the invention
shown at 932 and it corresponds to the sound
powered receivers illustrated in Figs. 1 to 8 in
clusive.
The receiver is connected across the
has its widest use and most logical application
secondary coil 920 and condenser 922, this coil
condenser combination forming a well-known
in connection with the receivers. However, since
the transmitters of the sound-powered type do
anti-side-tone. portion of the‘ sub-station circuit.
It has .been previously mentioned in the speci?ca
not differ either in structure or function'from
tion that ,for maximum e?iciency during recep
the sound-powered receivers, that the invention
is equally applicable to the transmitting units.
tion the impedance of receiver .932 must match
the impedance of the circuit across which it is 10 Accordingly, the invention, in its broader sense,
should be considered useful and applicable to
connected, or stated differently, it must 'match
the impedance of the circuit looking into the
the receiving as well as the transmitting units.
line. .when it is measured across the junction
points 936 and 931. In the. prior art all methods
of adjusting the sensitivity of receiver 932 used
some means for varying the impedance of the
While the invention vhas been described with
reference to several particular embodiments, it
will be understood that various modi?cations of
the apparatus shown may be made within the
receiver circuit, either by tapping coil 938 of the
receiver, inserting a series resistance with this
scope of the following claims.
I claim:
1. A sound-powered receiver including a per
coil; or shunting it by means of a shunt re
sistance. With the tapped coil arrangement, as 20 manent magnet, a sound coil, a working magnetic .
circuit for said magnet and said coil, and an
mentioned before, the impedance of the receiver
adjustable magnetic shunt making said receiver
is reduced in the ratio of 50 to l, i. e. at high
sensitivity the impedance of the receiver is ?fty
a continuously variable sensitivity receiver, said
shunt being positioned with respect to said cir
times higher than at low sensitivity. Such large
change in impedance acts, for practical purposes,
cuit so as to maintain the impedance of said
coil substantially constant through the sensitivity
as a short-circuit for all other receivers which
may be connected to the receiving end of the line
in a conference call which prevents all other re
ceivers from participating in the conversation.
range of said receiver.
2. A sound-powered telephone unit including
a permanent magnet, a working magnetic circuit
Thus adjusting of the sensitivity of one receiver 30 connected to said magnet, a magnetic shunt
varies the sensitivity of all other receivers.
mounted in said unit, and mechanical instru
mentalities for varying the position of said shunt
Moreover, since during transmission the approxi
with respect to said magnetic circuit for varying
mate balanced condition of the alternating cur
the sensitivity of said unit with the impedance of
rent bridge formed by the substation circuit and
said receiver remaining substantially constant.
the line is obtainable only with the character
3. A sound-powered receiver including a sound
istic line impedance, the bridge will be more un
coil, a permanent magnet, a working magnetic
balanced when the line impedance is other than
thev characteristic impedance, and as a conse
circuit connected to said magnet, and a variable
quence, with the low impedance'receiver con
magnetic shunt for varyingthe reluctance of said
magnetic circuit, thereby varying the sensitivity
nected across the bridge, the side-tone signal
through the receiver will be higher.
of said receiver, said magnetic shunt being so
The magnetic shunt principle used for adjust
positioned with respect to said sound coil as to
maintain the impedance of said coil substantially
ing the sensitivity of the receiver is illustrated in
Fig. 9 by the permanent magnet‘ H), the ferro
constant while the position of said shunt is varied
magnetic plate It, disc [2,. and the adjustable
'
- between its operating limits.
magnetic shunt 2B which may be shifted to a
4. A telephone substation circuit including a
su?ciently close position with respect to plate
sound-powered unit, and magnetic instrumen
talities for varying the sensitivity of said unit
with the impedances of said. substation circuit
l4 and disc I2 so as to shunt in part the air gap
24 as described previously in connection with
Figs. 1 to 8 inclusive. This adjustment of the
position of the shunt element 28 does not alter
. remaining constant over the range of sensitivity
of said unit while the. position of said instru
mentalities is varied between the operating limits.
5. A telephone sub-station circuit including an
the di?iculties. outlined above are avoided; this
is true throughout the range of the sensitivity of
anti-side-tone circuit, a variable sensitivity
the receiver because the magnetic shunt 28 is
sound-powered receiver connected to said anti
positioned so that its plane is parallel to the
side-tone circuit, a sound coil in said receiver,
the impedance of said ‘coil having a predeter
magnetic axis of the coil. Since the coil is
surrounded by the U-shaped members 28 and
mined relationship to the impedance of said anti
22, it has a magnetic path of its own of very low
side-tone circuit, and adjustable magnetic ‘in
reluctance, and, therefore, only an insigni?cant 60 strumentalities within said receiver for varying
amount of leakage ?ux will reach the magnetic
the sensitivity of said receiver with said relation
ship of said impedances remaining substantially.
path offered by the magnetic shunt 28. Thus
constant over the available range'of sensitivity
the. impedance of the receiver is not a?ected !by
the shunt irrespective of its position.
of said receiver.
,
In the sound-powered unit illustrated in Figs.
6, In a telephone unit, the combination of
means for producing a working magnetic flux, a
1 to 8 inclusive, another equally advantageous
position may be found for placing the magnetic
plurality of paths for said ?ux, instrumentalities
shunt, and it is the position occupied by the non
transductively coupled to said ?ux, andra mag
magnetic spacer H3. The mechanical arrange
netic shunt in variable magnetic - relationship
ments illustrated in the drawings for shifting 70 with respect to said paths for varying the trans
the position of the shunt may be applied to the
ducing e?iciency of said instrumentalities solely
by varying the density of said working. magnetic
magnetic shunt when it is placed in the vplane
of'the non-magnetic spacer I 8.
flux.
The invention has been described in connec
NICHOLAS T. VOLSK.
tion. with the sound-power unit which. has been 75
the impedance of the receiver,v and, therefore,
Документ
Категория
Без категории
Просмотров
0
Размер файла
784 Кб
Теги
1/--страниц
Пожаловаться на содержимое документа