Note: Descriptions are shown in the official language in which they were submitted.
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The present invention relates to meter reading
apparatus and in particular to a novel and improved
electronic apparatus for obtaining usage information from a
meter, converting such information to electrical signals for
transmission to another location, and thereafter converting
the signals to observable in~ormation indicative of such
meter information or storing said signals for future
retrieval.
In United States Patent No. 3,852,726 entitled
"Remote Meter Monitor" there is shown and described apparatus
for remotely monitoring meter information wherein a clock-
type utility meter within a house is monitored and the meter
reading is converted to a digital readout at a remote
location outside of the house. This meter monitoring
apparatus essentially comprises a circular array of magnetic
reed switches mounted upon each dial of the meter, with a
reed switch located in registry with each numeral on each
dial. ~ach dial also has a pointer having a magnetic free
end which actuates the reed switches on the respective dial
successively as the pointer traverses the dial face, thereby
producing digital signals representing an analog-type meter
reading. The digital signals are transmitted by cable to a
remote location outside of the house to provide a numerical
digital readout by means of a decade array of light emitting
diodes which are electrically in circuit with the respective
reed switches.
The aforementioned meter monitor apparatus shown in
~` United States Patent No. 3,852,726 is effective in enabling a
utility company meter reader to obtain information as to meter
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usage ~rom outside the house in which the meter is located,
without having to gain access to the interior of the house.
However, each of the dials of the meter requires the
installation of ten magnetic reed switches thereon~ so that
;n the usual clock-type utility meter having at least four
dials, at least forty magnetic reed switches are required,
so that the apparatus is expensive to manufacture and install.
In addi~ion, the appara~us is adaptable for installation only
on clock-type meters and cannot be used on other types of
meters such as odometer-type meters.
It is an object of the present invention to provide
meter reading and monitoring apparatus of a simplified con-
struction which is more economical in manufacture and
instaLlation and in which only a single hermetically-sealed
magnetic reed swi~ch is emplo~ed in the meter. The single
reed switch is preferably positioned in association with the
meter dial which indicates the lowest unit of utility usage
and is connected within a logic circuit which adds up the
usage units and transmits the sum, when desired, to a remote
location where ~ readout is provided.
Another object of the in~ention is to provide meter
reading apparatus of the character described which is capable
of gathering meter information and storing the same over
extended periods of time, and for i~mediate retrieval when
desired.
Another object of the invention is the provision
of meter reading apparatus of the character described which
utilizes a single magnetic reed switch associated with prox-
imate magnetic means carried by a functional rotatable disc
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motivated by the flow through the meter of a particular
utility such as water, gas, electricity or the like, which
apparatus can be easily incorporated into existing meters
without any major modification.
Still another object of the invention is the
provision of a meter reading apparatus of the character
described which is capable of providing meter information
which can be coded, stored and later retrieved by the utility
company from time to time for readout or printout either at
the user's premises or at a remote location by telephone or
radio triggering devices.
A further object of the invention is the provision
of a meter reading apparatus of the character described which
is adaptable for use in hazardous environments since the reed
switch is hermetically-sealed and of microampere output and
the reed contacts cannot be exposed to volatile gases or the
Like.
In accordance with the invention there is provided
: meter read;ng apparatus for use with a meter having at least
one rotatably driven dial element indicating units of utility
measured by the meter. The meter reading apparatus comprises
magnetic means mounted on the dial element of the meter for
rotation therewith, and a single magnetic field sensitive
: element fixedly mounted on the meter and positioned to
register intermittently with the magnetic means as the dial
element is rotated to produce an electrical signal in
response to each field interception during rotation of the
dial element. The meter reading apparatus also includes
signal processing means for receiving the electrical signals
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to produce a unit pulse indicative of each field inter-
ception of said sensitive element by said magnetic means,
counting means for receiving and summing said pulses to
indicate the total units of utility measured by said meter,
storage means for receiving said total units of information
of u~ility measured and storing the same for future
information, and interrogator means for selectively
interrogating the storage means for receiving and transmitting
information as to ~he total units measured over a selected
time period.
In one preferred embodiment of the invention, the
meter is a clock-type meter having a plurality of dials
associated with rotatable pointers, and the rotatably driven
dial element is a disc mounted on the pointer drive shaft of
one of said dials. The magnetic field sensitive element is
a magnetic reed switch mounted proximate to said disc, and at
least one magnet is mounted on the disc in a position to
register with the magnetic reed switch and actuate the same
to close and reopen as the magnet traverses the switch. This
closing and reopening of the reed switch produces the
electrical signal which is indicative of a selected unit of
~ utility consumption measured by the meter and which is con-
; verted ~o said unit pulse by the signal processing means.
In another embodiment of the invention, the meter
is of the odometer type with a series of discs arranged
parallel to each other in a row, and numerals from zero to
nine eq~lally spaced about the circumference of each disc.
A permanent magnet is mounted between each adjacent pair of
numerals on the di~sc which indicates the lowest units of
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u~ility consumption measured by the meter, and the magnetic
reed switch is so located that it is traversed by the magnets
successively as the disc rotates.
Additional objects and advantages of the invention
will become apparent during the course of the following
specification when taken in connection with the accompanying
drawings, in which:
FIG. 1 is a plan view of the index face of a
typical clock-type gas meter having dial faces calibrated in
multipLe units of cubic feet, and showing magnets and a
magnetic reed switch, constituting a portion of the meter
reading apparatus of the present invention, associated with
the two foot dial of the meter;
FIG. 2 is a side elevational view of the two foot
dial of the meter of FIG. 1, showing the positioning of the
magnet and magnetic reed switch associated therewith;
: FIG. 3 is an enlarged plan view of the two foot
dial and associated meter reading structure shown in FIG. l;
FIG. 4 is a side elevational view of two of the
dials of an odometer-type meter, showing the manner in which
magnets and a magnetic reed switch are associated therewi~h in
accordance with the present invention;
: FIG. 5 is a side view of the odometer dial shown
in FIG. 4 showing the magnets and magnetic reed switch
associated therewith; and
FIG. 6 is a schematic and f-mction block diagram
showing the switch and electronic portions of the meter
reading apparatus
Referring in detail to the drawings, there is
shown in FIG. 1 a preferred embodiment of meter reading
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apparatus made in accordance with the present invention, and
applied to the dial plate 10 of a meter 12, which for pur-
poses of illustration is shown as a gas meter. The dial
plate 10 is ~ormed with dials 14, 16, 18 and 20 which
respectively represent volume of gas usage in decade stages of
millions, hundred thousands; ten thousands, and thousands of
cubic feet. ~wo additional dials 22 and 24 represent volume
of gas usage in increments of one-half cubic foot and two
cubic fee~ respectively.
Each of the dials 14, 16, L8 20 and 22 is associated
with the usu~al pointer 26, but, for purposes of the inventiDn
herein, the dial face 24 underLies a circular disc 28 which
is affixed to the pointer shaft 30 of ~the dial 24.
Mounted on the under surface of the disc 28 are a
pair of permanent magnets 32 and 34 which are equally spaced
radially from the pointer shaft 30 and are diametrically
; opposed from each other. Mounted on the dial plate 10 beneath
the disc 28 is a hermetically-sealed magnetic reed switch 36
which is positioned to register with the respective magnets 32
and 34 as the disc 28 is rotated. The reed switch 36 has the
usual contacts 38 and 40, which, in FIGS. 1 and 3 are shown in
open position~ When either of the magnets 32 or 34 move into
registry with the reed switch 36, the contacts 38 and 40 are
closed in response ~o the magnetic field created by said
magnet.
In FIG~ 2 there is shown a side view of the disc 28
and its underlying dial plate 10. In this view it will be
seen that the pointer shaft 30 mounting the disc 28 extends
through the dial plate 10 and also through an underlying
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plate 42, terminating in a crank arm 44, which is of a well-
known construction and which is turned by th~ conventional
bellows assembly (not shown) of the ga~ meter. The shaft 30
also carries a toothed gear 46 which meshes with conventional
gearing (not shown) of the gas me~er to drive the pointers 26
of the other dials 14, 16, 18a 20 and 22 in their proper
ratios.
Since the dial 24 is calibrated to indicate the
flow of two cubic feet of gas, the disc 28 turns through one
complete revolution with each passage of ~wo cubic feet of
gas. In one complete revolution of the disc 28 each of the
two magnets 32 and 34 will come into registry with the under-
lying reed switch 36, so that the contacts 38 and 40 of the
reed switch are closed twice for each revolution of disc 28,
i.e., the reed switch 36, which is normally open, is closed
once in response to passage of one cubic foot of gas. It
will be understood that the meter reading apparatus of the
present invention may be installed in gas meters of other
constructions or in meters of different types, such as water
meters, electric meters, etc. In meters in which the lowest
unit dial is constructed to provide one revolution for the
passage of one cubic foot of gas, only one magnet will be
mounted on the disc 28, and the reed switch 36 will be closed
once for each revolution of the disc 28, represen~ing the
passage o~ one cubic foot of gas.
The contacts 38, 40 of the reed switch 36 are
electrically connected to an external receiving device such
as a logic chip 48, by leads 50 and 52. As shown in FIG. 1,
the logic chip 48 may be mounted on the d;al plate 10.
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As the disc 28 rotates, each magnet 32 and 34 will
successively move into registry with the magnetic reed switch
36, and when the magnet is directly over the reed switch and
at maximum flux density, the switch contacts 38 and 40 will
close to make contact. As the magnet moves away from reed
switch 36, the magnetic field is weakened and the switch
contacts 38 and 40 open. The reed switch 36 thus produces a
pulse, indicating the passage of one cubic foot of gas~ and
each such pulse is fed to the logic chip 48, energizing
circuitry therein, as will be presently explained.
FIGS. 4 and 5 illustrate another embodiment of meter
to which the magnet and reed switch of the invention are applied
the meter in this instance-being of the odometer type. An
odometer-type meter includes a plurality of`closely-spaced
; 15 parallel discs in which calibration numerals are printed on
;; the disc peripheries, and each disc depicts ten units numbered
from zero to nine. In this type of meter, the disc on the
right-hand end indicates units from zero to nine, the next
disc represents units from ten to ninety, the next disc
hundreds, etc. Each complete revolution of one disc indexes
or causes the next adjacent disc in the sequence to turn
through the increment of one unit, etc.
FIG. 4 shows two of the discs 58 and 60 of an
odometer-type meter5 each having a circumferential row of
equally-spaced numerals 62 numbered from zero to nine. The
disc 60 represents single units of passage of cubic feet of
gas, while the disc 58 represents units of tens, and
additional discs (not shown) will represent units of hundreds,
thousands, ten-thousands, etc. as required.
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In accordance with the invention herein, a
permanent magnet 64 is mounted between each of the numerals
62 on the disc 60, and a magnetic reed switch 36, identical
to that shown in FIGS. 1 and 3, is mounted adjacent the disc
60 in such a position that the magnets 64 move into successive
registry with the reed switch 36 to close the la~ter once ~or
each succeeding passage of one cubic foot of gas. With each
closing and opening of the reed switch 36, an electrical
signal or pulse is generated through leads 50 and 52 to the
logic chip 48, where the pulses are selectively processed to
provide subsequent digital information relative to the amount
of utility used or consumed by the customer, as will now be
described.
FIG. 6 is a schematic block diagram illustrating
the circuit components of the logic chip 48 of FIG. 1, and
showing the manner in which the pulses produced by the reed
switch 36 are converted to information indicative of the
parameters used to measure the item under observation. The
logic chip includes an ~C input network in which a DC power
source 70 is con~ected through a resistor 72, and capacitor 74,
to ground. The reed switch 36 has one end connected to ground
and the other end adapted for connection to terminal 76
connected to the junction of resistor 72 and capacitor 74.
Logic chip 48 further includes a Schmitt trigger
circuit 78 having its input connected to junction terminal 76
and its output connected to summing logic circuit 80 whose
output is connected to the input of shift register memory 82.
In order to provide for interrogation of memory 82,
logic chip 48 includes a control logic circuit 84 and an
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oscillator circuit 88. The control logic circuit 84 has an
input lead 86 and an output lead 87 connected to memory 82.
The output oscillator circuit 88 is respectively connected to
memory 82 and control logic circuit 84.
In operation, when a magnet is in close proximity
to reed switch 36, the magnetic field produced by the magnet
causes reed switch contact 38 to close. Contact 38 will thus
remain closed until a reduction in the magnetic field intensity
caused by the departure of the magnet releases contact 38,
allowing it to open. The closing and opening of reed switch
36, in response to the passage of the magnet into and out of
proximity therewith, causes the RC network to produce a pulse
waveform 90 at junction 76 in the following manner:
WhiLe reed contact 38 is open, capacitor 74 will be
charged up to a voltage approaching the voltage of DC power
source 70, this voltage level indicated by line 92 in wave-
form 90.
Closure of reed contact 38 under the influence of
the magnetic field produced by a magnet causes reed switch 36
to short circuit capacitor 74 to ground, thereby causing the
voltage level at junction 76 to drop sharply to ground level
as indicated by line 94 in waveform 90. The departure of the
magnet and the removal of its magne~ic fleld from reed switch
36 allows reed switch 36 to open thus allowing capacitor 74
to gradually charge up through resistor 72 and DC power supply
70 toward the voltage of the latter, at a rate determined by
the values of resistor 72 and capacitor 74. The rising
voltagP at junction 76 clue to this charging action is indicated
by line 96 in waveform 90.
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Schmitt trigger circuit 78 is operative to produce
a sharply stepped (i.e. square wave) output for input wave-
orms of varying and irregular slope. Thus, Schmitt trigger
circuit 78 will "fire" when the voltage input thereto exceeds
a predetermined voltage level to produce the square waveform
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In operation, when the voltage input to Schmitt
trigger circuit 78 drops from level 92 to level 94, the
voltage output thereof indicated by waveform 98 will sharply
rise from voltage level lO0 to level 1020 As ~he input
voltage rises, Schmitt trigger 78 will not "fire" until the
input voltage indicated by line 96 reaches a predetermined
level and when it does so the output voltage will sharply
drop as indicated by line 104 in waveform 98, thus producing
a sharp square wave output pulse for each input pulse pro-
duced at junction 76.
Because Schmitt trigger circuit 78 will fire only
when the input voltage thereto exceeds a predetermined value,
ripples in the voltage at junction 76 caused by bouncing of
reed contact 38 or other sources of electrical noise will be
of insufficient magnitude to cause Schmitt trigger circuit 78
to "fire'l. Accordingly, Schmitt trigger circuit 78 prevents
the production of erroneous noise pulses and provides a
'Iclean'' square waveform for each opening and closure of reed
switch 36.
- Output pulses 98 are fed to summing logic circuit 80
which counts the same and feeds this pulse count information
to shift register memory 82 which receives and stores this
pulse count inforn1ation and makes such informa~ion subjec~ to
retrieval upon demand.
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When it is desired to "read" the pulse count
information in memory 82, an interrogating signal is applied
via lead 86 to control logic circuit 84 which causes memory 82
to feed the pulse count information through its output 106
to a data meter reading display (not shown).
The input and ou~put leads 86, and 106 may be
connected to a socket member located at the exterior of the
building in which the meter is located, the manner described
in United States Patent No. 3,852,726. In this instance, a
meter reader emp].oyed by the utility company may plug in a
portable monitor unit which will display a reading representing
the total units of utility measured by the meter. Preferably,
- however, the leads 86 and 106 are employed to tie in the logicchip 48 to a telephone circuit for remote readout or printout
by the utility company. The interrogation signal may be
transmitted through input lead 86 via the telephone line when
desired by the utility company, or the meter information may
be retrieved at regular pre-arranged intervals by means of a
computor system. This may be accomplished by means of tape
on which the telephone numbers of individual customers are
;~ recorded, so as to call automatically at programmed times and
at off hours, wîthout ringing the telephone bell of the
customer. The information withdrawn from the IC chip memory is
recorded on tape for transfer to a readout or printout device.
The same system can be applied to remote gas or oil weLl meters
for which helicopters or boats are normally used to obtain
readings. Readings from these industrial meters can be
obtained via radio, upon signaL from a central station, to
be recorded or displayed. The apparatus of the present
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invention is thus adaptable for use in any type of meter or
device where a continual reading of gas or fluid is required.
The system is foolproof since the original mechanical readout
of the meter is always available for checking by a direct
reading without the loss of vital information.
The extremely low drag of the magne~ and reed
switch combination makes the meter reading assembly highly
suitable for use with electrical meters. The memory employed
is preferably of the type which stores information magnetically,
so that it is capable of retaining the stored data, in the
event that the main system power is shut down or interrupted,
for as long as a period of 300 hours. A Ni-cad battery can
also be incorporated in association with the power supply so
as to extend the period of memory storage time, where necessary.
While preferred embodiments of the invention have
been shown and described herein, it is obvious that numerous
omissions, changes and additions may be made in such embodiments
without departing from the &pirit and scope oi the invention.
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