Note: Descriptions are shown in the official language in which they were submitted.
~2~7QOC
Background of the7`Invention
The present invention relates to an electronic thermometer f
which is preferably of the rechargeable type and which displays
the sensed temperature in a digital manner. The present temper-
ature also relates to an electronic thermometer having an
improved probe construction wherein temperatures can be reg;s-
tered in relatively short periods of time.
The prior art electronic thermometers operate adequately
but there are certain disadvantages associated with ~hese
10 devices. For example, the oral ard rectal probes are both
accommodated by the same probe receiving passage in the device
thus presenting the passible problem ot cross-inFection.
Furthermore, these prior art devices permit one to insert the
probe into the device even when the cover is still on the
probe. Thus, the probe with the used cover on it might be le~t
in the device thereby causing further spreading of growth of
infection.
The prior art electronic thermometers have a package of
probe covers associated therewith which are normally carried
20 by the nurse in her pocket. These packages of probe covers
are easily spilled and easily contaminated as they usually are
handled when inserted on the probe.
The prior art devices are also limited in their mode of
operation. Usually these devices determine when the ~emperature -~ ;~
has stabilized and record this as a reading. But in the prior
art they did not provide alternate modes of operation. However,
in accordance with this invent;on the device may be operated
either in a one-shot manner or can be operated continuously.
A~cordingly9 one object of the present invention is to
30 provide an improved electronic ~hermometer having as one of its
1i .
IRll ~~OOC
unique features the use of a hols$er for the probe wherein the
holster may be inserted and is removeable from the device so that I ~;
a second holster and assoc;ated probe can be inserted into the
device9 the two probes being used for oral and rectal tempera~ures.
Another object of the present invention is to provide a
device as set forth in the preceding object and which is auto-
clavable. Because the prior art devices did not teach the use
of a holster for the probe the entire device had to be sterilized
but the sterilization was limited to gas sterilization and the
entire device could not be autoclavably s~erilized.
A further object o~ the present inventian is to provide an
electronic thermometer having a holder associated therewith
for receiving a cartrid~e of probe covers wherein the cartridge
is received in a locked position and the probe covers are pre-
vented from spilling from the holder.
Still a further object o~ the present invention is to
provide an electronic thermometer having an easily read dig;tal
display panel and wherein the device is further provided with an
audible signal tha~ indicates when the patien~'s ~emperature is
to be read.
Ano~her object of the present invention is to provide an
electronic thermometer that us rugged in construction, uses
solid state eleckronics, and is battery operated with a re-
charged and storage stand.
A further object of the present invention is to provide
an electronic thermometer that can be used to monitor in the ;~
usual manner where readings may be taken after, for example9 a
30 second time interval~ or where it can be used in a continuous
manner to monitor a patient's temperature for applications in
operating~ recovery and intensive care situations
i
~3~
~ .
Still another object of the present invention is
to provide an improved cartridge for holding a plurality of
probe covers wherein the cartridge may be opened in either
of two different manners, which locks into the holder for
the cartridge, and is yet easily removed once all of the probe -
covers have been used.
Still a further object of the present invention
is to provide means for the operator to easily check the
accuracy of the instrument so that even a relatively unskilled
person can operate the device effectively.
Summary of the Inventlon
An electronic thermometer system of the present
invention comprises a transducer means including probe means
responsive to body temperature and providing analog signal
representative of sensed temperature. There is provided
means for periodically monitoring the analog signal and
converting the signal to a representative digital number,
and means for displaying the digital number which indicates
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5;~7
the body temperature. A timer means is provided for
demarcating a predetermined time period, and mode control
means are included for providing continuous monitoring
wherein the means for periodically monitoring is permitted
to operate continuously and for providing one-shot operation
wherein the periodic monitoring .is enabled but only until
the predetermined time period has terminated.
A more specific aspect o~ the present invention -~
has to do with the mode of operation~ As mentioned above, :
this device may be used either in a one-shot mode o-f
operation wherein a person'sitemperature is to be taken
only once, or can be used in a continuous mode of
,
.
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11 2170`0~
37
operation under special circumstànces. For this type of opera-
tion there is provided a switch means which permits either eon-
tinuous operation or operation over a predetermined time period
a~ the end of which a temperature is registered and an audible
alarm is sounded indicating that the reading may now be recorded
by the nurse. In the continuous mode there is no audible signal
and ~he tempera~ure is continuously displayed in a strobed
fashion, In order to provide this type of operation there is
included in addition to the mode switch, a t;mer whieh may be
in the form of a monostable multivibrator which in turn controls
a bistable ~ode device. In one s~ate this device permits con-
tinual resetting for the continuous mode of operation. In its
other state which occurs after the monostable ~ultivibrator has
ended its time period~ this device prevents ~urther resettincJ
ancl enables an audible and visual circuit for generating an
audible and visual signal that indicates that final reading has
been taken by the dev;ce.
i~rief Description of the Drawin~s
Numerous other objects~ features and advantages of
the invention should now become apparent upon a reading of the
following detailed description taken in conjunction with the
accompanying drawings, in which:
FIG. l is a perspective view of a device constructed in
accordance with the principles of this invention,
FIG. 2 is a cross sectional plan view taken through the
probe cover cartridge holder;
FIG. 3 is a side view of the probe cover cartridge in
its unfolded condition;
FIG. 4 is a cross sectional view taken alon9 line 4-4
of FIG. 2 and through the complete holder and cartridgei
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'1? ~C
FIG. S is a side view of the device shown in FIGo I with
the probe holster withdrawn to show the switch array;
FIG~ 6 shows the internal constructio~ of the probe
holster with half of the holster removed to expose the internal ~.
construction;
FIG. 7 is a somewhat enlarged cross sectional view of
the probe with the probe cover in place;
FIGS. 8-10 are electrical schematic diAgrams of the
electronics associated with the device of this invention; and
FIG. 11 shows waveforms associated with ~he diagrams in
FIGS. 8-10.
. . ,
De~ailed Description
Referring now ~o FIG. 1, there is shown the device of
~he present invention which is primarily contained within
housing 10 having a digital display 12 at the front thereQf.
The device 10 sits upon a platform 14 which contains a recharger
uni~ not shown in FIG. 1. This recharger unit may comprise a
cord for receiving AC power and a recharger coil having a mating
coil disposed in the device 10 for ~he purpose of charging
bat~er7es ~hat are con~ained in the hous;ng. Th;s port;on of
the circuitry is discussed in more detai1 hereinafter with
re~erence to the electronic schematic diagrams.
FIG. 1 also shows, ins~rted into the device 1OD a probe
holster 16 having the probe 18 inser~ed therein and partially .
extending therefrom. A solicone rubber curl-cable 20 couples
~rom the probe 18 to an ;nternal connection in the holster 16.
Regarding ~he probe and hslster shown in FIG. 1, m~re detailed
reference will be made hereinafter to this portion of the
invention shown in FIGS. 6 and 7.
. _ _ _ . .. ., . _ _, .. , _ , . .. . . ~ . . ~
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The platform 14 also defines a recess 22 for receiving
a second holster 16 and associated probe 18. One of the probe
and holster assembl;es may be for oral use and the other may be
for rectal use. As is discussed in more detail hereinafter, the
curl-cables associated wi~h the holsters are each fixed wi~hin
the holster and thus the probes cannot be exchanged between
holsters.
FIG. 1 also shows9 mounted to the top wall of the device
10, a holder 24 for holding a cartridge 26 of probe covers. In
FIGo 1 3 single holder 24 is shown. However9 as noted herein~
after in FIG. 53 two such holders can be staoked one on top of
the other to provide increased capability.
FIG. 1 shows the device of the present invention in a
standby position wherein the device 10 is resting in the plat-
form 14 and the device, or the batteries thereof9 is being
recharged for subsequent use. When a user9 such as a nurse, is
required to take a plurality of separate readings from patients~
the device is removed from the platform and the proper holster
and probe assemb1y is inserted into the device. As indicated in
FIG. 1, ~he device is preferably provided wi~h a comfor~able
neck strap 28 which can be used ~or carrying the device at
approximately chest level and in easy viewing range. In this
position it is also noted that the probe covers of the oartridge
26 are maintained in an upright position and because of the
improved design of this cartridge these probe covers are fixed
in position.
When a reading is to be ~aken the probe 18 is withdrawn
from i~s hols~er 16 and ;rser~ed in~o one of the probe covers
30. The fit between the probe and the probe cover9 as dis-
cussed in morè detail hereinafter, 7S a friction fit and thus
8-
.
_-~ I ~
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12/i~ 7
when the probe is withdrawn the cover ;s withdrawn therewith.
A-fter this operation the probe with the attached cover is ;n-
serted into the body of the person where the temperature is
desired to be taken and as soon as a predetermined temperature
of say 90F is reached~ a digital read;ng on the display 12 is
noted. If the device is be~ng used in ~he one-shot mode9 after
a predetermined time period of say thirty seconds, the display
freezes at its last reading and an audible alarm i5 sounded to
indicate to the nurse that this reading ;s to now be reocrded.
The probe is then withdrawn from the patient and the probe cover
is discarded. The probe is then inserted into the holster and
the device is then in readiness for the taking of a subsequent
temperatureO
Alternatively, if the device is being operated in the
continuous mode, the probe is maintained in the patient and a
digital reading is continuously disp1ayed on the display 12.
Referring now to FIGS. 1 S~ the holder 24 comprises ~`
top and bottom sections 32 and 34 which can be glued or spot
fastened togethe~ ~o define a chamber for the cartridge 26.
2~As indicated in FIG. 59 these sections 32 and 34 are slightly
tapered. FIG. 2 shows the ridge 36 extending vertically from
sidewalls 37 of the bottom section 34. Similar ridyes are
provided in the top section for interlocking the cartridge 26
into the holder 24.
The holder 24 is secured to the device 10 by means of
a pari of posts 38 which extend upwardly -From the top surface
oF the device 10 and engage with slots 39 in the bottom section
34~ as indicated in dotted in FIG. 2. Similarly, a second set
of posts 40 are engageable with slots in a top holder 24A shown in
FIG. 5. Actually9 a greater number of holders can be stacked
. ~ ' ' .'~ ~' ''
7~ 0 0 C
in the manner shown in FIG. S with the use of the post and slot
arrangenlent.
The cartr.idge 26 comprises a cardboard backing 42 that
has a perforation line 44 along which a fold may occur. This
perforation line 44 divides the backing into sections 42A and
42B. A transparent plastic cover 46 defines with the backing
42 a plurality of individual probe cover chambers each of ~hich
contains a probe coYer 30. The transparent cover 46 has a
peripherdl edge 47 which is secured such as by gluing to the
baoking 42. The transparent plastic cover 46 also has a
perforation line 48. The cover 46 is continuously formed to
define facing in line chambers for the probe covers and is
closed at its opposite ends 50 as shown in FIG. 3.
When the nurse desires to use a new cartridge 26 which
may be taken from a cartridge dispenser which is not shown in
the drawings9 the cartridge may be folded along either perfora-
tion line 44 or perforation line 48 to a folded condition shown
in the fragmentary view in FIG. 49 and as is also shown irl FIG.
1. Once this fold~has taken place in either direction, the
perforation line that has not been separated forms a hinge for
maintaining the cartridge in a single piece. The folded car- t
tridge is then inserted in~o the holder 24 and the probe covers and
the entire cartridge are maintained locked in pos;tion at
least in part by means ot the no~ches ~1 provided in the backing
which ~ate with the ridges 36. By tapering the holder 24 this
also assists in main~aining the cartridge and its probe covers
in a relatively secure position in the holder. Once the probe
covers have all been used the cartridge is oollapsable and9 as
noted in FIGS. 1 and 29 the holder is provided wi~h a front :
;O recess so that the cartridge can be easily withdrawn. .
:
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,12/70~C
~ 2 ~ ~
FIG. 5, in addition to showing. the double stacking of
the holders 24 and 24A, also shows the slot 53 which accommo-
dates the holster 16 which has been withdrawn in the view shown
in FIG. 5 to expose a switch array 54. The swi~ch array 54
includes three calibration switches 55, 56 and 57. The
operation of these switches will be discussed in more deta;l
hereinafter with reference to the schematic diagrams shown in
FIGS. 8-10. FIG. 5 also shows a gain control knob 58 and an
of~set control knob 59 which are also discussed in more detail
hereinafter'wîth reference to the schematic diagrams. The
mode of opera~ion of the device is controlled by control knob
60 which basically has two different positions~ one of which
provides one~shot or peak monitoring and the other one of which
prov;des continuous monitoring. The function of this sw1tch or
control knob will also be discussed in more detail hereinafter.
FIG. 6 shows the probe holster 16 with one-half of
the housing defining this holste,r removed to exp~se the internal
structure of the holster. When the removed section is placed
over the half shown in- FIGo 6~ the components are mainta;ned in
'~ a locked posit;on. in FIG. 6 the probe 18 has been removed from
the holster 16. The probe 18 is normally inserted into the
metal tube 62 which has successive steps of sma'ller diameter.
The tube 62 wi'll line the probe up with contact 64 of switch 66
which is secured to a mounting plate 68. When the probe is in
the holster, the sw~ich 66 is in i~s open position and power is
interrupted to the electronic circu;try of the dev;ce. Al-
ternatively, when the probe is removed switch 66 is closed.
FIGo 6 also shows ~he curl-cord 20 which couples by way of a
standard connector 21 to ~he output printed circuit board
~0 connector 69. There are two leads coupled from the connector 21
-to the connector 69 and there are also two additionally
coupled from the switch 66 to the connector 69. The printed
circuit board connector 69 is o-f special construction in that
connections are made to both sides of the connector board so
that the holster can be inserted in one of two different posi-
tions without changing the electrical connections. The con-
nector 69 mates with another connector part (not shown3 of the
housing 10.
One of the important features of the present inven- :
10 tion is the use of this holster which accom~odates only the
probe associated therewith. To provide this operation, the
cable 20 has a sleeve 70 with a flange 71 associated therewith.
When the two halves of the holster 16 are assembled, bjhe flange
71 prevents the cable 20 from be:ing withdrawn from the holster
at that end. Another important feature of the holster and
probe assembly is that the entire assembly is autocla~able
without having to sterili2e the entire device. Also, with the
use of a tube 62 the probe cannot be inserted into the holster
: 16 when a probe cover is attached to the probe~ In the prior
art devices, the probe wi-th a probe cover attached thereto
could be inserted back into the device and thereby cause fur-
ther infection and contamination.
FIG. 7 shows a cross-sectional view of the probe with
a probe cover in place on the probe~ The probe 18 shown in FIG. ;
7, generally comprises finger grip assembly 74, elongated tubu-
lar probe 76, barrel 78, harrel 80, and cable 20. The finger
grip assembly 74 comprises base member 82 defining a mid-wall 83.
A cylindrical member 84 which is made of plastic fits within one
end of member 82 and abuts against wall 83. A metallic tube 86
passes through a central aperture in members 82 and 84 and is
flanged at 87. Before assembling these parts, a spring 89 is
placed between wall 83 and annular -flange 90. The tubular piece :;
- 12 -
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; ~ ;" . . ~ ~ :
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86 and the cylindrical member 84 move in unison and relative
to the finger grip member 82. An end button 92 may be secured
in place over the end of the cylindrical member 84.
The metallic tubular probe 76 may pass througll the
aperture in the tubular member 86. A second spring 94 is dis-
posed contacting the flange 90 and at its other end contacting
flange 95 of the tubular barrel 78. The barrel 80 may then be
inserted over the ~ubular probe and the barrel 78 and ~its
within the other end of the finger grip member 82. The barrel
80 and member 82 may be fixed in relative position by means of
an epoxy glue. As previously mentioned, the probe also com-
prises the elongated tubular metal probe member 76 which has
a thermistor 96 disposed at one end thereof. This thermistor
is covered by a small metallic cap 98 which closes that end of
the tubular probe 76. At the other end of the tubular probe
there is provided a hermetic seal which may be a glass to metal
seal 99. A conductor wire 100 couples from the thermistor
inside of the tube to a somewhat larger rod 102 which is
insulaked by means of seal 99 from ~he outer metal tubular
20 probe.
The cable 20 has a connector coupled to the end thereof
which is a conventional connector and there ls provided a
segment 106 of tube of approximate1y the same diameter as tubular
probe 76 which Fits over the connector 104. One terminal of the
connector couples to the rod 102 and the other terminal of the
connec~or is wound to contact the segment 106 which is in turn
in conductive contact with the tubular probe 76.
FIG. 7 also shows the probe cover 30. The probe cover
30 includes a first segment 1109 which in the position shown in
FIG. 7 is in in~imate contact with the cap 98 of the tubular
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.,, ~ .. . . . . .
~/7~
~ 7
probe 76. The segment 110 and the cap 98 are constructed so
tnat there is a slide fit and when the probe cover is inserted
onto the probe this slide fit provides sufficient friction to
hold the probe coYer onto the probe. The probe cover shown in
FIG. 7 is constructed en~irely of metal and is coupled by means
of a frustoconic section 111 to a second segment 112 which has
an internal diameter that is greater than the diameter of the
tubular probe 76, thereby providing an air passage therebetween.
The sPcond segment 112 is connected by means of another frusto~
conic section 113 to a third segment 114 which is open at its
end. The segment 114 is of larger diameter than segment 112 and
is adapted to fit over the barrel 80, as indicated in FIG. 7.
In operation, when the cover is forced onto the probe
by inserting the probe into the cover, springs 89 and 94 compress
and are held in compression by the friction fit at the surface
between segment 110 and cap 98. When the cover is inserted the
button 92 is urged outwardly from the finger grip assembly 74.
In order to release the probe cover the button 92 is depressed
thereby causing springs 89 and 94 to act. Springs 94 and 89
which were previously under compress;ons then release and the
probe cover is ejected from the probe. Barrel 78 and spring 94
advance the cover away from probe 76 beyond ridge 111 thus
allowing venting and ~ree release of the cover from the probe.
The shank 78 when relaxed also provides the feature of protect-
ing the thin~alled probe 76 from bending or collapsing acciden-
tally. The spring action is such that by depressing the button
929 the friction fit between the segment 110 and the cap 98 is
broken. Because the segment 112 is made larger than the probe,
there is no vacuum that is crea~ed and the probe cover easily
,0 disengages from the probe.
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~1 1 2../~iOOC
~0~;2~7
The probe cover of the present~;nvention is believed to
be an improved design. For one thing9 because of the stepped
arrangement of this probe cover it is easily releasable from the
probeO The probe cover is preferably made from all aluminum and
is disposable. The three segments of the probe cover may have
diameters on the order of .115", ~165" and .250", respectively.
The probe cover provides a fast thermal response, is comparative-
ly economical, is shaped with no sharp corners that ~ight cut or
otherwise injure soft tissue, is made from non-toxic material
lo and is substantially safer than two-piece probe covers which
may on occasion separate when in use. If desired the probe
cover may be coated.
FIGS. 8 10 show the circuitry that is associated with
the electronic ~hermometer of this invention. FIG. 8 shows the
analog circui~ry in'cluding comparison circuitry. FIG. 9 shows
some of the timing circuits associated with the electronics.
FIG. 10 shows the digital counting circuitry9 the control cir-
cuitry and the coding and display driving circuitry.
Referring now to FIG. 8, there is shown the batter-ies B
which have their negative terminal coupled to the converter 120
shown in FIG. g. This converter 120 is of standard design and
simply converts the battery voltage to predetermined voltage
levels ~V and -V. Battery B couples by way of switch 66 to the
~V line 121. The atteries are charged by means of a recharger
circuit 122 which receives an input AC signal which is coupled
to the frequency converter 123. The output of converter 123 is
a higher Frequency signal than the typical 60 cycle signal and
this signal is coupled by means of transformer 124 and diode
126 to the batteries. A light emitting diode 12~ is coupled in
30 series with resistor lZ9 and both of these are in parallel with
-15
~r ~
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J12/ZQaC
the secondary winding of the transformer 124. When the device
10 is in the position shown in FIG. 1 an ;nductive recharging
occurs by way of transformer 124 and the light emitting diode
128 is lit. Diode 12~ is visible in the display 12 and in-
dicates ~hat the batteries are bein~ recharged. When the device
is lifted from the recharger pla~form 14 the diode 128 is
extinguished.
When the probe and holster assembly is inserted into the
device, such as in the position shown in FIG. 19 and when the
lo probe is still in the holster9 the swtich S6 is open and because
switch 56 is also normally open there is no power provided to
the circuitry shown in FIGS. 8-10. However, when the probe is
withdrawn from the holster the switch 66 closes and power is
provided on line 1~1 and to other portions of the circuitry.
When the probe and holster assembly is not in the device then
the swtich 56 may be operated tu enable the device and take non-
probe temperature readingsO
FIG. 8 shows the thermistor 96 coupled to common line 130
and also to the o~f-set potentiometer or knob 590 The wipe arm
of the potentiometer 59 couples to operational arnplifier 132
which has appropriate biasing resistors associated therewith.
In order to check the accuracy of the system there is also pro-
~ided switches 55 and 57 which are normally open but may be
closed to inser~ prede~ermined resistances in series with
potentiometer 59. The off-set potentiometer 59 is also control-
lable as indicated in FIG. S to adjust this calibration. The
resistor associated with switch 55 is preselected to indicate
a minimum point of expected operating range such as a temperature
of 90F. Alternatively9 the swtich 57 is in series with a
resis~or ~hat is preselected to operate at an upper limit of the
-16-
2/
range such as at 108F. These two sl~itches should be used
periodically to check the accuracy of -the readings to see -that
the off-set is set for -this predetermined temperature range.
FIG. 8 also shows a second amplifier device 134 which has
an inpu~ coupled froln the gain potentiometer 58. The output of
device 134 establishes a set reference level which is used in
the analog digital converter.
The analog digital converter is of the up-down converter
type. For example~ this may be a converter such as the one
shown in Ana~o~ ~0 O~g~a~ D~g~a~ to A~ o~ CC~LVQ~ O;~
~QC~n,~qUQ~ by DaYid F. Hoeschele, Jr. 7 specifically as shown
on pages 381-384. The basic idea o~ the up-down converter is
to generate a pulse w;dth~proport;onal to the analog input
voltage by making a time comparison between two integrations.
The proportional pulse w;dth is taken at the output of the
comparator 136, shown in FIG. 8. The first ;ntegration is on
the input analog siynal. It proceeds for a fixed interval of
time and the input to the integrating circuit is then switched
to a known referen,ce voltage. The time from this switching until
~o the integrator output reaches the init;al ~ixed re~erence point
provides a measure o~ the analog input voltage. This sequence
of operation is reFerred herein as the up integrate (UI) and
down integrate (DI).
The analog digita1 converter colnprises, irl addition to
comparator 136 an integrator 138 having a capacitor 139
associated therewith~ electronic switches 140 and 141 and NOR
gate 142. The UI and DI signals control the switches 140 and
141 and the gate 142. The output of gate 142 in turn controls
a third switch 143. In the sequence of operation to be dis-
cussed in more detail hereinaFter, the UI and DI signals are
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both initially low causing conduction o~ switch 143 and a
discharge o~ capacitor 139 prior to the initiation o~ an up
integrate sequence. ~hereafter, an up integrate sequence
occurs and switch 1~0 is rendered conductive with the signal
from device 132 being coupled to the integrator 138~ There-
a~ter during the dow~l integrate sequence, the switch 141 is
conductive to couple with signal from device 134~to the inte-
grator 138. The output from integrator 138 couples to one
input o~ comparator 136. The comparator 136 has an output as
indicated ln FIG. 11 which is normally high and goes to its
low state when the integrator output is of suf-ficient positive
value. The circuitry shown in FIG. 8 is arranged so that this
comparison does not take place until the thermistor 96
registers a reading o~ at least 90F. The adjustment o~ the
o~f-set is instrumental in controlling this comparator output.
Of course, the total operation of the analog to digital con-
verter shown in FIG. 8 is dependent upon the UI and DI signals
which are control signals. The output from comparator 138 is
referred to as the COMP signal shown in FIG. 11 and is coupled
to the control logic shown in FIG. 10. The output ~rom com
parator 136 also couples to NOR gate 138A which receives
another input which is actually the UI signalO The output
~rom gate 138A is also shown in FI~. 11 and is coupled to the
mode control switch 60. The swi:tch 60 is shown in solid in its ~`
one-shot mode o~ operation and is shown in phantom in its
continuous mode o~ operation. In the one-shot mode of opera-
tion, the output ~rom gate 138A is coupled to the monostable
multivibrator 1~0, shown in FIG. 9~ In the continuous mode o~
operation, switch ~0 couples the input o~ the multivibrator
directly -to the -V voltage level.
The monostable multivibrator 140 shown in FIG. 9 may
,~ `I
___ _ _ '^' `--~___ __ _ ., _ _ ~ _ _ ., .. _. '' "-- _ ., .
, .
~112~700C
be adJusted to provide different time periods at its output.
FIG. 11 shows the typical 30 second output of the multivibrator
140 which is ter~ed the TIME OUT output. This output is coupled
to the logic circuitry sho~n in FIG. 10 and this 30 second
interval represents the time over which the temperature is taken.
~ecause the comparator 136 does not have an output until 90
this 30 second interval represents an interval of 30 seconds
from the time that the probe first senses a 90F reading. The
multivibrator 140 is a standard design and has an output that
~o is low during the 30 second interval. The multivibrator 140
also ~enerates a power clear signal which is a positive pulse
used primarily in the circuitry of FIG. 10 as a set pulse.
FIG. 9 also shows the master clock 142 which is of
conventional design and has its resistors and capacitors
. ,
selected so that the output frequency from the clock is lKHz or
thereabouts. The reset clock 144 also shown in FIG. 9 is
similar in design to the master clock 142 but includes an en-
abling gate 146. When the reset enable signal which is coupled
from the circuitry of FIG. 10 is low the reset clock is enabled
and reset pulses occur at a predetermined time period. In
accordance with one aspect of this invention the reset clock is
acljustable to pro~ide a reset pulse every half second. This
reset signal is in essence an update signal meaning that every
half second the analog data is updated. Thus in the one-shot
mode of operation ~here are approximately sixty resets that
occur during the 30 second interval until a final probe reading
is registered.
FIG. 9 shows a further clocking circuit 148 which is
referred to as the beep or audible circuit. This is an
oscillator that has an audible signal device 14~ coupled thereto.
.
_ 1 9-
~ ffl~ 7
lR112/700C
When the input enable line lS0 goes to its low state the
oscillator is enabled and an audible signal is generated by the
signal device 149. The c;rcuit 148 and the reset clock 144 are
operated mutually exclusively so that as long as resets are
occurring there is not an audible signal occurring. After the
end of the reset interval in the one-shot mode of operation
then the reset clock is inhibited and the beep circuit is
enabled.
FIG. 10 sllows much of the control logic that is used
~O in controlling the analog to digital conversion and which also
controls the counters 152 and 154. Each of these counters is
of conventional design and include a count enable input, a strobe
input and a clocking input. The counters 152 and 154 are inter-
connected so that they in essence form a single sequencing binary
counter. The counters 152 and 154 are only permitted to count
when the clock enable input is at its low level. The output
~ro~ the counters is coupled to the drivers and display 156
which comprise transistor drivers and light emitting diodes
forming seven segment characters. Actually, the counters 1~2
~O and 154 a1so comprise deciding which provides the proper outputs
for driving the light emitting diodes to form the proper decimal
characters corresponding to the binary count ln these counters.
The operation o~ the electronics is initiated by with-
drawal of the probe from the holster. When ~hat occurs power
is immediately provided and the power clear signal sets the
flip-flop 160. In this condition its assertion output is low
and thus the reset clock 144 occurs and this signal resets
the counters 152 and 154 and also the other flip-flops 162a 164
and 166. The flip--flops 164 and 166 are J-K toggle flip~ flops.
The reset signal which resets flip-flop 162 causes its assertion
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output to be low thus enabling the counters 152 and 154. This
action initiates the clocking sequence and the clock pulses are
coupled to the counter by way of line 163 from the clock input
from the master clock 142. This initiation of the counters is
indicated in FIG. 11. as occurring at tome To~
On the occurrence of the reset the ou-tput from the
counter 154, shown in FIG. 11, is at its high state commenciny
at time To7 and this signal is coupled by way of NOR gate 155 to
the circuitry showr1 in FIG. 8. The signal that is coupled is the
UI signal which is low during the time that the output from
counter 154 is high. The DI signal at the output of flip-flop
166 is also low and thus the gate 142 shown in FIG. 8 has a high
output causing a discharging of the capacitor 139. This dis-
charge sequence is an initial sequence prior to the up integrate
sequence.
The up integrate sequence commences when the counter
154 output goes to its low state thereby providing a high level
output froln the gate 155. This starts the up integrate sequence
with switch 140 b``eing conductive ~see FIG. 8). FIG. 11 shows
the up integration during a predeterrnined time period which may
be on the order of 25 milliseconds. At the end aF this time
period the output from the counter 154 at time T2 goes to its
high level inhibiting the up integration. This high level
signal in sequence clocks both flip-flops 164 and 166 and starts
the down integration by virtue of a high level DI signal.
During the time from Tl to T2 the comparator 136 is
indicating an outpu~ and if it is assumed that switch 60 is in
its continuous mode position the flip-flop 160 is maintained in
its set state and ~he reset clock is continuously enabled. There
is no termination of the up dating. Also, it is noted that the
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CO~P signal is low and thus the flip-flop 162 is maintained
reset.
After a predetermined time period indicated in FIG. 3
as occurring at time T3 the comparator output 136 terminates as
indicated in FIG. 1l and the flip~flop 162 sets. When this
occurs the counter enable signal terminates and the counters can
no longer count upon the receipt of clock pulses. Also, the
negation output from flip-flop 162, along with the proper
polarity clock pulse prov;des a pos;tive strobe pulse at the out-
put of r~OR gate 170. This strobe signal is passed by way of aninverter 172 to two further NOR gates 174 and 176. The output
from gate 170 is also coupled to the counter 152 and from there
by way of line 153 to counter 154. This strobe signal essenti-
ally enables the dec,oded output from the counters which then
drive the appropriate transistors 178 and LED's 179 comprising a
part of the driver and display 156. This strobe signal is also
coupled by way of counter 154 and line 180 to transistor 182
which operates three segments of a digit. This strobe signal is
also coupled on iine 183 to transistor 184 for lightin~ certain
other segmen~s of the same digi~.
Because the temperature range as far as the most
significant dig;t is concerned w;11 be either a 9 or 10, only a
few segments of the character 9 need be changed to corvert the 9
to 0. Also, ~he character 1 can be represented by only two ¦
segmen~s. The gates 174 and 176 along with the transistors 186
and 187 control these ~if~erent segments to illuminate either a
9 or a 0.
Thus, at time T2 when we start the down integrate~ the
flip-flop 164 may again be reset if the temperature is over 100F.
In that case the gate 174 has a high enabling output and transis-
tor 186 drives two segments 190 and 191 for displaying the
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character 1. Also this transistor 186 drives a third segment
192 for con~pleting the character 9. Alternatively if a reading
of less thatn 100 is registered then the gate 176 is enabled as
the flip-flop 164 did not become reset. In that case the
transistor 187 is enabled for driYiny a segment 193 -to complete
~he 9 character.
For the tiMe being we are assu~ing that we are operating
in the continuous mode of operation and thus after the con~ersion
has occurred with the up and down integra~e sequence the counters
are maintained inhibited until the next reset pulse occurs a-t
which time flip-flop 162 is reset and the counters are a~ain
enabled. The sequence then repeats with a new digital number
being d;splayed based upon the new analog signal level. In tnis
invention the strobe signal is a pulse signal as shown in FIG.
; 11 but is of relatively short duration and thus the display is
displayed in a flash mode rather than a continuous mode of
display with the strobe flashes occurring at the clock rate.
In the one-shot ~ode of operation the switch 60 is in the
position shown in.solid in FIG. 8 and the signal from gate 138 is
coupled to the monostable device 140. After this device has
timed out over a period of say 30 seconds as indicated in FIG.
11~ this causes the flip-flop 160 to become reset. The negation
outpu~ oF the flip-flop 160 thus becomes hiyh and inh;bits any
further reset pulses From the reset clock 1~4~ At the same tin~e
the assertion output fro~ the ~lip-flop 160 is low and thus the
beep circuit 148 is enabled. Thus9 after the 30 second time inter-
val the disp1ayed reading is nlaintained and the beep circui~
indicates that the reading has been concluded and can now be
recorded.
This applica-tion is a division of application Serial
No~ 242 500 filed December 15 19750
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