U.S. patent number 3,657,715 [Application Number 05/027,750] was granted by the patent office on 1972-04-18 for ultrasonic paging system.
Invention is credited to William J. Curtin.
United States Patent |
3,657,715 |
Curtin |
April 18, 1972 |
ULTRASONIC PAGING SYSTEM
Abstract
A system for paging or calling persons without disturbing anyone
other than the person or persons being paged. A transmitter applies
an electrical signal to a power line at a predetermined ultrasonic
frequency indicative of the person sought. The power line is
connected to a plurality of power outlets into which are plugged
transducers which convert the electrical signal into an ultrasonic
signal at the same frequency. The ultrasonic signal is broadcast
from a speaker at each transducer and detected by the person
carrying an ultrasonic detector responsive to that frequency.
Inventors: |
Curtin; William J. (Madison,
WI) |
Family
ID: |
21839567 |
Appl.
No.: |
05/027,750 |
Filed: |
April 13, 1970 |
Current U.S.
Class: |
367/197; 367/191;
340/288; 340/7.58 |
Current CPC
Class: |
G08B
3/1008 (20130101) |
Current International
Class: |
G08B
3/00 (20060101); G08B 3/10 (20060101); G08b
001/02 () |
Field of
Search: |
;340/216,416,224,311,312
;325/64,55,361 ;179/2.5 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Habecker; Thomas B.
Claims
What is claimed and desired to be secured by United States Letters
Patent is:
1. An ultrasonic paging system comprising an electrical
transmitter, a plurality of electrical outlets, wire network means
coupling said transmitter to said outlets, and transducer means for
converting an electrical signal from said transmitter into a
corresponding ultrasonic signal, said transducer means being
plugged into at least one of said outlets.
2. A paging system according to claim 1 wherein said transducer
means includes means for broadcasting said ultrasonic signal into
the area adjacent said transducer means.
3. A paging system according to claim 2 wherein said broadcasting
means includes a speaker.
4. A paging system according to claim 1 including at least one
portable ultrasonic detector for detecting an ultrasonic signal
from said transducer means.
5. A paging system according to claim 4 wherein said detector
includes means for selectively detecting only certain ultrasonic
signals from said transducer means.
6. A paging system according to claim 5 wherein said detector is
frequency selective.
7. A paging system according to claim 1 wherein said wire network
means is a power network for transmitting electrical power.
8. An ultrasonic paging system comprising an electrical transmitter
for producing an electrical signal at ultrasonic frequencies, a
plurality of electrical power outlets, power wire network means
coupling said transmitter to said outlets, and transducer means for
converting an ultrasonic frequency electrical signal from said
transmitter into a corresponding ultrasonic signal and broadcasting
it into an adjacent area, said transducer means being plugged into
one of said outlets.
9. A paging system according to claim 8 including an electrical
power source coupled by said network means to said outlets.
10. A paging system according to claim 9 wherein said source
comprises a conventional 110 volt 60 Hertz electrical source and
said outlets include a plurality of conventional wall outlets.
11. A paging system according to claim 9 wherein said network means
is the electrical power supply network of a building.
12. A paging system according to claim 11 wherein some of said
outlets are inside said building and some are outside.
Description
This invention relates to a system for paging or calling individual
persons from a group without disturbing the remainder of the group
and more particularly is directed to such a paging system which
requires a minimum modification of existing equipment so as to be
relatively simple and inexpensive to install and operate. The
system of the present invention is particularly adapted for
"in-plant" use, such as for paging individual members of a hospital
staff and for use in clinics, manufacturing plants, office
buildings, and the like, including parking lots and yards.
As is well known, paging systems very often take the form of a
plurality of loudspeakers spaced throughout the building or area in
which the person sought is expected to be found. The person's name
or other identifying data customarily is broadcast simultaneously
over all of the speakers in the hopes that the person sought will
be in sufficient proximity to one of the speakers so as to hear it,
recognize his name, and take appropriate action to respond to the
person seeking him. In many establishments, and in particular in
hospitals where doctors and other staff personnel are frequently
being sought, the frequent broadcasts over the loudspeaker system
can be annoying and distracting, especially to patients who may be
in need of rest.
The present invention avoids this difficulty by providing a paging
system in which a plurality of loudspeakers broadcast ultrasonic
vibrations or "silent sound" so as not to disturb or annoy persons
within the broadcast range of the speakers other than the person or
persons being paged.
An important feature of the present invention resides in the fact
that it utilizes the conventional electrical 110 volt wiring of the
building, such as a hospital or plant, as the electrical
transmission media for the paging system. All that is basically
required in the system is one or more page boxes which may be
plugged into the conventional electrical outlet to broadcast the
"silent sound" and a suitable detector carried by the person or
persons wanted by the pager. The signal to be detected is
transmitted from the originating point into the electrical wiring
system of the building as an electrical wave in the ultrasonic
frequency band. This wave is picked up by a unit plugged into any
110 volt outlet in the system. This is somewhat similar to a
wireless intercom system whereby one person may communicate with
another using the 110 volt wire as the communication path for the
audio modulated ultrasonic frequency. The difference between a
wireless intercom and the system of the present invention is that
in a wireless intercom the ultrasonic frequency is detected and the
audio modulation comes out of the speaker of the plugged in
intercom device, whereas in the present invention the plugged in
device or page box does not detect and rectify but instead picks up
and amplifies the ultrasonic electrical frequency and instead of
sending out audio acoustical energy into the adjacent area, it
sends out or broadcasts ultrasonic acoustical energy into the room
or area surrounding the speaker. This "silent sound" may be
provided in any area desired by simply plugging in the page device
to an electrical outlet of the building wiring system. The detector
carried by the person or persons sought over the paging system may
be in the form of a so-called "fat" device resembling a fountain
pen which contains a battery, an audio amplifier, and an acoustic
pickup. It should be provided with a selective feature, such as a
filter or the like, and makes it possible for a person to be paged
anywhere in the plant or on adjacent ground which may be supplied
by electrical wiring outlets.
It is therefore one object of the present invention to provide an
improved silent paging system.
Another object of the present invention is to provide an ultrasonic
paging system of relatively simplified and inexpensive
construction.
Another object of the present invention is to provide an ultrasonic
paging system in which electrical signals at ultrasonic frequencies
are transmitted over the conventional electrical wiring system of a
building or other structure in which the paging system is
installed.
Another object of the present invention is to provide an ultrasonic
paging system in which so-called "silent sound" signals are
broadcast from one or more page boxes plugged into the 110 volt
outlets of a conventional building wiring system.
Another object of the present invention is to provide an ultrasonic
paging system in which a signal is sent over a conventional
electrical 110 volt wiring system at an ultrasonic frequency, this
signal is received and converted in a page box to a corresponding
ultrasonic sound signal and broadcast into an adjacent area by the
page box, and detected by the person being sought through an audio
detector to provide an audible, visual or other signal which may be
sensed by the person carrying the detector to apprise him of the
fact that he is being sought.
These and further objects and advantages of the invention will be
more apparent upon reference to the following specification,
claims, and appended drawings, wherein:
FIG. 1 is a block diagram of an overall ultrasonic paging system
constructed in accordance with this invention;
FIG. 2 is a perspective view of a conventional wall outlet showing
a page box plugged into one of the outlet sockets;
FIG. 3 is a side view of the outlet and page box of FIG. 2; and
FIG. 4 is a partially diagrammatic view of a building incorporating
a paging system constructed in accordance with this invention.
Referring to the drawings, the paging system of the present
invention is generally indicated at 10 in FIG. 1 and comprises a
conventional 60 hertz 110 volt AC power supply or source 12 which
may be a conventional electrical service line for supplying 110
volt electrical energy to a building, plant or similar edifice. An
electrical signal from source 12 passes by way of a conventional
building wiring system, exemplified by wires 14 and 16, to a
plurality of electrical outlets indicated by the dashed boxes 18,
20, and 22. Coupled to the electrical network including leads 14
and 16 by way of leads 24 and 26 is an electrical transmitter 28.
By way of example only, transmitter 28 may take the form of a low
frequency oscillator producing a sinusoidal electrical output on
leads 24 and 26 at a frequency in the ultrasonic range, i.e.,
25,000 hertz and higher. Transmitter 28 preferably comprises a
variable frequency oscillator so that the output signal on leads 24
and 26 may be varied, preferably in steps, to produce signals
having a frequency indicative of the person sought over the paging
system 10.
If necessary or desirable, the ultrasonic frequency signals from
transmitter 28 may be prevented from interfering with source 12 by
inserting a low pass filter 30 into the system between source 12
and transmitter 28. In this way, the low frequency, i.e., 60 hertz
signals, from source 12 may pass through filter 30 to the outlets
18, 20, and 22, but the higher frequency electrical signal from
transmitter 28 will not pass through the filter 30 to source
12.
Plugged into each of the outlets 18, 20, and 22 is a page box as
indicated generally at 25, 27, and 29. Each of page boxes is
preferably of identical construction and basically comprises a
transducer for converting or transducing the electrical signal on
leads 14 and 16 from transmitter 28 into a sound or pressure signal
of the same shape and frequency. The page boxes are connected to
respective speakers 32, 34, and 36 for broadcasting the "silent
sound," i.e., the pressure or sound signals at ultrasonic
frequency, into the air or atmosphere adjacent the speakers as
indicated at 38, 40, and 42 in FIG. 1. Each of the page boxes 25,
27, and 29 preferably includes an electrical amplifier for
amplifying the signal from the transmitter 28 before it is
transduced or converted into a pressure or sound signal. The
converter or transducer may be of any conventional construction,
such as a well known piezo-electric device, capacitive transducer,
or the like, for converting electrical signals into pressure or
sound signals acting on the surrounding air. Speakers 32, 34, and
36 may be of conventional construction and serve to funnel or
direct the pressure signals produced in the page boxes into the
areas of a room, parking lot, hallway, or the like, which the
respective outlet serves. That is, the speakers 32, 34, and 36 act
in the same manner for the ultrasonic waves as they would act for
audible waves at a slightly lower frequency and broadcasts them so
as to produce the ultrasonic waves indicated at 38, 40, and 42.
These latter waves are picked up by respective detectors 44, 46,
and 48. Again, these detectors may be of conventional construction
and, by way of example only, each may comprise a so-called "fat"
device resembling a fountain pen which may be carried in the pocket
of a person to be paged and which contains a battery, an audio
amplifier, and an acoustic pickup, and which is preferably provided
with a selection or coding means, such as a filter, peculiar to the
person carrying the detector. The detectors are preferably
connected to respective speakers 50, 52, and 54 for producing an
audible signal in response to the impingement on the detector of
ultrasonic waves of the proper frequency.
By way of example only, the transmitter may be set by the operator
or sender of the paging signal at a predetermined ultrasonic
frequency, which frequency is indicative of and peculiar to a
particular person being sought who has been previously assigned
that frequency. That is, the detector 44, 46, or 48 carried by the
person being sought is preferably provided with a filter or other
selection device which will pass the one particular frequency at
which the transmitter 28 is set but which rejects all other
frequency signals from the transmitter. In the example given, it is
assumed that the transmitter 28 is set at a frequency for example
of 25,000 hertz so that sound waves 38, 40, and 42 at the
ultrasonic frequency of 25,000 hertz are transmitted from each of
the boxes 25, 27, and 29 by way of speakers 32, 34, and 36. This
frequency is rejected by detectors 44 and 46 so that speakers 50
and 52 are not energized. However, the filter in detector 48 has
been previously set to pass this frequency and an audible output is
produced at speaker 54 of sufficient strength to apprise the
carrier of the detector that he or she is being paged. It is
apparent that in place of an audio output speaker 54, the detector,
as well as the other detectors, may be provided with an optical
indicator, such as a light or other similar device. While three
detectors 44, 46, and 48 are shown, it is understood that in normal
operation many more detectors would be provided, i.e., one for each
person who might be sought over the paging system. Similarly, the
number of page boxes would be varied in accordance with the area to
be covered and the number of available electrical outlets.
FIGS. 2 and 3 are front and side views, respectively, of a typical
outlet, such as the outlet 22 of FIG. 1. The outlet shown is in the
form of a conventional wall outlet and includes the usual faceplate
55 through which pass receptacles 56 and 58 adapted to receive a
conventional two or three prong plug. Plugged into the upper
receptacle 56 by prongs 60, as shown in FIG. 3, is the page box 29.
In this embodiment, the page box is preferably provided with a pair
of speakers 36 and 36' for broadcasting the ultrasonic signals and
with a plurality of control and adjustment knobs as indicated at
82.
FIG. 4 is a partially diagrammatic view of a four-story building
incorporating the novel paging system of the present invention. In
FIG. 4, an electric light pole 64 is illustrated as supporting
electrical lines 66 which supply electrical energy over
conventional service lines 68 to a building 70. The surface lines
pass through one of the walls 72 of the building and terminate at a
service box 74. The four-story building is provided with the four
floors indicated diagrammatically at 76, 78, 80, and 82 and with a
roof 84. On each of the floors, on the roof, and on the outside
front and back walls 72 and 86, respectively, are a plurality of
conventional 110 volt outlets 88 corresponding to the outlets 18,
20, and 22 of FIG. 1. Transmitter 28, mounted in this example on
the second floor 78, is connected to all the outlets 88 by way of
leads 90, 92, 94, and 96 which are all connected together
internally of the service box 74. Service lines 68 are connected to
these leads, preferably through an isolation device such as the low
pass filter 30 of FIG. 1 which may also be located in or adjacent
service box 74. When the transmitter 28 is energized, an electrical
signal at an ultrasonic frequency appears at each of the outlets
88. With a paging box plugged into one or more of these outlets,
the detector on the person being sought will give an audible or
visual indication upon receipt of a signal at a predetermined
frequency from transmitter 28. It is understood that if desired
other encoding arrangements may be utilized in place of the
frequency spacing described.
It is apparent from the above that the present invention provides
an improved "silent" or ultrasonic paging system which operates
such that only the person being sought is interrupted or distracted
by an audible or visual signal. An important feature of the present
invention resides in the fact that it utilizes one or more page
boxes which are plugged into conventional outlets of an existing or
conventional 110 volt electrical wiring network and which boxes
cooperate with a transmitter connected to the network to receive an
electrical signal which is supplied from the transmitter via the
electrical wires of the network. This ultrasonic electrical signal
is converted or transduced in the page box and broadcast as a
"silent" or pressure signal at the same ultrasonic frequency. The
sound signal is detected by a suitable detector carried by the
person being paged to produce a preferably audible sound signal
apprising the carrier of the detector that he is being sought by
the person operating the transmitter. In the preferred embodiment,
the detectors are provided with bandpass filters which pass a
particular ultrasonic frequency and reject all others so that the
person being sought is identified by the frequency produced by
transmitter 28 and each transmitter frequency is peculiar to a
particular individual who may be paged by the system.
The invention may be embodied in other specific forms without
departing from the spirit or essential characteristics thereof. The
present embodiment is therefore to be considered in all respects as
illustrative and not restrictive, the scope of the invention being
indicated by the appended claims rather than by the foregoing
description, and all changes which come within the meaning and
range of equivalency of the claims are therefore intended to be
embraced therein.
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