CA1150972A - Temperature sensing probe and disposable probe cover - Google Patents

Abstract

TEMPERATURE SENSING PROBE
AND DISPOSABLE PROBE COVER
ABSTRACT
This invention relates generally to a tempera-ture sensing probe and disposable probe cover adapted for use with an electronic thermometer. A disposable cover for an electrical probe is known, wherein the cover includes a thermally insulating plastic body formed together with a heat conductive metal tip.
However, forming the cover with a body and tip portion of dissimilar materials is costly and increases the expense of employing the device. Moreover, such ar-rangement generally has included an electrical probe having a spring biased probe shaft mounted for axial reciprocation, thereby adding further to the cost and complexity of the device. The present invention over-comes these deficiencies by providing an improved probe and cover arrangement. The temperature sensing probe includes a probe shaft rigidly mounted on a handle and having a temperature sensing tip at the distal end of the shaft. A disposable cover is provided in the form of a unitary elongated tube constructed of heat con-ductive material and having an open proximal end arranged to slide over the probe shaft and a closed distal end arranged to tightly engage the temperature sensing tip of the shaft in order to retain the cover on the shaft and provide a positive conduction of heat to the temperature sensing tip. For the purpose of selectively ejecting the cover after temperature measurement, the probe handle includes a movable ejec-tion button for manually driving the cover forwardly with sufficient force to disengage the cover from the tight engagement with the temperature sensing tip.

Description

TEMPERATURE SENSING PROBE
AND DISPOSABLE PRO~E CO~ER

TECHNICAL ~IELD
This lnventlon relates generally to improvements ln thermometer devices and, more particularly, to a new and lmproved temperature sen~lng probe and disposable probe cover, the probe and cover being adapted for use with an electronic thermometer BACKGROUND OF THE PRIOR ART
It is common practlce ln the medical arts, as in hospitals and in doctors' offices3 to mea~ure the body temperature o~ a patlent by means of a glass bulb ther-mometer lncorporating a heat respon~lve mercury column which expands and contracta adJacent a calibrated temper-ature scale. Typlcally, the glass thermometer is inserted lnto the patlentJ either orally or rectally, and subse-quentl~ removed after a ~u~ficient time interval has passed to enable the temperature of the thermometer to stabillze at the body temperature of the patient. This time interval is u~ually o~ the order of 2 to 4 minutes.
After a suf~ic~ent period of time has elapsed, the therm-ometer is removed ~rom the patlent and i~ subsequently raad by appropriate medlcal personnel.
~5 In order to make another temperature mea~urement, e,gO, elther on a ~econd patient or on the same patlent a~ a later time, a second, sterLle thermometer must be used, or the first thermometer must be cleaned, sterillzed and redistrlbuted prior to reuse.
Xt wlll be apparent ~rom the foregolng that con-ventional temperature measurement procedure~ u~ing glas~
bulb thermometer~ are prone to a number of very ~ignl~icant deficlencles In this connection, glass bulb thermometer~
are rather frag~le devices whlch are easlly broken and, indeed, such breakage i~ very common. In addition, temper-ature mea~urement is rather slow and, for patients who cannot be rel~ed upon (by vlrtue o~ age or inflrmity) to properly retain the thermometer for the nece~sary period of ~naertion in the body, may necessitate the physical pre~ence o~ medical per~onnel during a relatively long Q~?~

measurement cycle, khus wasting valuable time. Further-more, glass bulb thermometers are not a~ qulck and ea~y to read, particularly under poor l~hting condition~.
Moreover, such thermometers reguire a considerable degree ~f physlcal handling by the medical personnel who use them, thus increasing the chance~ of rein~ecting a patient or o~ cros~-contami~ation between patlents. In addition, and as previously polnted out, glass thermometers re~uire a co~tly ~ter~llzation and redistribution process.
Various attempts have been made by the prior art to mlnimlze or eliminate the aforedescribed deflclencles of the glass bulb thermometer by using temperature sensing probes o~ le~s fragile constructlon which are de~igned to operate in con~unction wlth dlrect readlng electrical thermometer instrumentation. However, such probes and electrical thermometers have typically proven to be rela-tively slow in making temperature measurements, and lt is ~till nece~ary to completely sterllize the probe after each u~e. Therefore, a large supply o~ probes ic neces-~ary and the relatively e~pensive sterillzatlon and re-di~trlbution co~ts l~till remain.
It 18 also known in the prior art to provlde ~lexlble and resilient covers or ~heaths for both glass bulb thermometer~ and electrlcal probe~. HoweverJ such prior art devlces are still slow and must be physi¢ally handled by medical personnel durlng installatlon and removal, with the resultant pos~ibllity of contarnination.
Furthermore, ~uch sheaths and cover~ are generally prone to puncturlng, tearln~, or belng stretched out of shape.
30 In addltion, such protective ~heaths have not alway~ pro-vided i.deal thermal contact between the sheath and the temperature sensln~ zone o~ the thermometer or probe and, consequenkly, the use of such protective sheaths may not produce conslstently reliable and accurate results.
35 Moreover, protective sheaths for glass bulb thermometers and electrical probes have typlcally been rather expen-slve.
Another ~olution which has been propo~ed ls the provision o~ a disposable cover for an electrical probe ~5~q7 whereln the cover -lncludes a relatively -lnexpensive khermally insulating plastic body formed together with a heat conductive mekal tip. This arrangement is dis-closed thoroughly in U. S. Patent No. 3,738l479, and al-thou~h this arrangement functions satisfactorily, formingthe cover with a body and tip portlon of dissimilhr mater-ials ls costly and increases the expense of employlng the device Morecver, the arrangement descr~bed in that patent includes an electrical probe having a spring bla~ed probe shaft mounted for ax~al reciprocation wlth respect to the probe body, thereby adding further to the cost and complexity of the device.
Accordingly~ in an effort to reduce the costs of medical care, there exists a need for a truly inexpensive temperature sensing probe and disposable probe cover which provide accurate, reliable, rapid and easily obtalned readlngs, and which obviate the problems of breakageJ ster-ilization, redistr-lbution, and contamination. As will become apparent from the following, the present invention ; 20 satisfies that need.
B~IE.~ SUMMARY OF THE INVENTION
Briefly~ and in general terms, tne present invention provides a new ancl improved temperature sensing probe and disposable cover which is arranged to be mounted on such a probe by tight engagement with the temperature senslng tip thereof, and further arranged to be selec-tively e~ected from the probe, The temperature senslng probe and probe cover are particularly adapted for use with electronLc temperature measurin~ instrumentation.
~asicalLy, the pre~ent lnvention lnclude~ a generally tubu:Lar cover whic~l ls lntended for use wlth a temperature sens~n~ probe having a probe shaft rigidly mounted thereon and a thermal sensor device mounted at the distal end of tlle probe shaft. The geometry of the probe cover is arranged 80 that, when a probe shaft is inserted into the cover, the thermal sensor at the end of the ~haft tlghtly engages the interior walls of the cover at the distal end thereof, and the body of the cover surrounds the remainder of the probe shaft. Manual means are pro-~.5~7;~

vided on the probe adJacent the proximal end of thesha~ to selectively engage the proximal end of the cover and dr-Lve the cover ~orwardly out of engagement with the thermal sensor device. By this arrangement, the cover is designed to ~acilitate easy installatlon onto and e~ection from the probe shaft without the need ~or direct physical contact or handling by the operator.
More speclfically, and in a pre~ently pre~erred embodlment, by way o~ example and not necessarily by way of limitation, the tubular probe cover is generally cylindrical to accommodate temperature probe shafts which are lLkewise generally cyl~ndrical, and the cover i~ open at its proximal end and closed at its distal end. The thermal sensor at the distal end o~ the probe sha~t is also generally cylindrical and, in order to cause the cover to tightly en~age the thermal sensor, the interior walls of the cover form a cone conver~ing toward the distal end of the cover. When the cyllndrical sensor is pushed into the distal end of the cover, the sensor engages the conical wall of the cover urging the wall radlally out-wardly. The resulting engagement between the distal end of the cover and the thermal sensor is sufficient to retaln the cover on the probe shaft during normal use of the shaft in temperature measurement.
To racilitate economy of manufacture, the cover is preferably formed as a unitar-y plece, such as by molding, and the specific materlal emp~oyed is preferably high density polyethylene. This materlal can be molded easily and convenlently to the desired configuratlon, provldes adequate and predlctable thermal conductivlty and the necessary rigid:~ty to functlon properly in the manner desired. That ls, slnce the thermal sensor engages the inside of ~he cover, and the outside of the cover is Ln contact w:Lth the t:Lssue or mater;Lal whose temperature ls to be measured, a positive communicatlon is established for conductlon of heat to the thermal sensor. Moreover, slnce the thermal conductlvlty and thickness of the cover materlal are known and can be reliably controlled, accurate and reliable temperature measurement~ can be -5~
taken using the temperature sensing probe and probe cover of this invention.
The probe cover is elongated and dimensioned to completely cover the probe shaft with the proximal end of the covex retained ad~acent a movable ejection means mounted on the probe near the proximal end o~ the probe shaft. The e~ection means i5 arranged to engage the proximal end of the cover and to ~electively urge the cover toward the distal end of the shaft. As mentioned above, the cover i constructed of a sufficiently rigid material so that applying an axial force on the prox~mal end of the cover will move the distal end out of engagement with the thermal sensor and permit the cover to be e~ected from ~he probe shaft Other features and advantages of the present lnvention will become apparent from the following detailed description, taken in con~unctlon with the accompanying drawings, which illustrate, by way of example, the principles of the inventlon.
2Q BRIEF DESCRIPTION OF T~ DRAWINGS
FIG. 1 is an elevatlonal view of a temperature sensing probe and probe cover embodying the present inven-tion and lllustrates a cover installed on a probe;
FIG. 2 is an elevational, ~ragmentary, partly ~ectional view ~ the temperature sensing probe and probe cover, slmllar to the view ~ FI~ illustrating the probe cover being eJected f~om the probe shaft, and belng partly broken away to il:lustrate the e~ection mechanism;
FI~. 3 is an enlarged, fragmentary, partly section-al view o~ the probe and probe cover of FIG. l;
FIG. 4 ls an enlarged, fragmentary, partly sec-tional view o~ the probe and cover, similar to the view of FIG. 3 and illustratlng the prohe cover disengaged from the probe shaft;
FICr. 5 ls a perspective view of an alternative temperat~re sensing probe and oover embodying the present invention; ancl FIG. 6 ls a diagrammatlc illustration of the spring-loaded e~ection mechanism of the probe of FIG. 5 taken generally along line 6-6 of FIG. 5, and showing a circuit controlling switch associated therewith.
DETAILED DESCRITPION OF T E INVENTION

AS shown in the exemplary drawings, the present invention is embodied in a temperature sensing probe, indicated generally by reference numeral 10 in FIG. 1, and as disposable probe cover 12 adapted for use with the probe. More particularly, the prove 10 is shown in the drawings as an electronic temperature respon-sive device which includes a thermal sensor 14 such as a ther-mistor or the like, at the distal end of a probe shaft 16 (FIG. 3),and which, when covered by the probe cover 12 can be inserted under the tongue of a patient for the purpose of measuring the patient's body temperature. The temperature sensed is converted to an electrical signal which is directed over a cable 18 as input to appropriate electronic thermometer instrumentation (not shown).
The general construction and use of temperature sensing probes and disposal covers is thoroughly described and illustrated in U.S. Patent No. 3,738,479 to Stephens N. Sato. Generally, the Sato patent describes the installation of a probe cover onto the probe shaEt, making a temperature measurement, and subsequent ejection of the probe cover from the probe shaft after use.
More specifica]ly, as describedin the Sato patent, a plurality of covers 12 are provided in a box with an open en(l 20 (FIG. 2 herein) of each of the covers accessible through an open end of the box. To install a cover on the probe shaEt 16, a handle 22 of the probe 10 is grasped by the operator of the probe, and the prob0 shaft is inserted throug}l the open end 20 oE the cover into the main body of the cover. Upon insertlng the probe shaft 16 completely into the cover 12, the distal end of the cover engages the thermal sensor 14 in a manner which will be described in greater detail hereinafter, and the cover is thereby retained on the probe shaft and can be removed from the box. With the cover 12 thus installed on the probe 10, a temperature measurement ' ,.P~

can be made in a conventional rnanner.
It will be noted from FIGS. 1 and 2 that, when the cover 12 is installed on the probe 10, an eJector button 24 is moved rearwardly. According].y, by manually moving the button 24 forwardly, tnereby moving a pair o~
pins 26 or like members forwardly against the prox~mal end o~ the cover, the cover can be easily e~ected ~rom the probe shaft after use without the necessity of phy-sical touch~ng of khe probe cover by the operator.
More specificallyJ as can best be seen ~n FIG. 2, the e~ector button 24 is mounted on the rearward end of a puaher tube 23 which is slidably received within the handle 22 and whlch engages the rearward end of a pusher fork 25 at its other end. The pins 26 are ~or~ed at the forward end o~ the pusher ~or~ 25 and are guided ~or axial reclprocatlon with respect to the handle 22 by being receivecl :ln a pa:lr of apertures 27 formed in the handle (FIG. 3).
It wlll be apparent rrom the foregoing descrip-.0 tion o~ the installation and eJection of a probe cover12, and the manner in whlch temperature measurement~
are made, that a new, c:Lean and d:l.spoaable probe cover is used ror eac~l new temperature mea~urement, and med-ical personne:l on:l.y hanclle the probe 10 which never comes into dLrect physlcal contact wlth the patient.
The prohe cover .12 ~ never touc~led by per~onnel at an~ time, elther ~r-lor to lnstal:l.atlon oI the cover onto the probe .1.0, durln~ in~al:lati.on of the cover onto the probe, cluring an actua.l. kemperature measure~-ment, dux-lng eJectlorl o~ the cover rrom the probe, or after probe disposal. Thus, satlitary condltions are asstlred and prob:l.ems of lnfection ancl cross-contamlnation ~rom equ-lpment or physical handling are avolded, In accordance with thepresent lnventlon, the probe sha~t 16 is rigidly mounted to the temperature senslng probe 10, and the probe 10 is provided with a unitary disposable probe cover 12 which is arranged to tightly surround and engage the sensor 14 at the tem-perature sensing tip o~ the probe to place the tip in ~ilS~7Z

heat conductive ~mmunicatLon wLth the tissue or material whose temperature is to be sensed. In accordance wlth a further feature of the -lnventlon, the engagement between the dlsposable probe cover 12 and the temperature sen~ing tip of the probe shaft 16 is sufficient to re-tain the probe cover in place on the shaf't until it is removed by depresslng the eJection button 22 which causes the plns 26 to bear against the proximal end of the cover and move the dlstal end of the cover out of engage-ment with the sensor 14. Moreover, theprobe and probecover of' this invention are relatively inexpensive to manufacture, convenient and reliable Ln use, and provide positive and predictable conduction of heat to the tem-perature sensor 14 while providin~ the desired protection from communLcation o.~ disease, without requiring repeated sterilizing of the probe~
Toward the foregoing ends, the probe cover 12 is elongated, general:Ly tubular, and includes an open prox-imal end 20 and a closed distal end 28~ ~he probe shaft 16 and temperature sensor 14 at the tip of the probe are generally cy:lindrical, and the lnslde diameter of the main portion of the tubular cover 12 is dimensloned to loosely surroun(l both the shal.'t and sen~or ~or the pur-pose o~ tlght:l.y engaglng the sen~or ~ , the inslde walls 30 ad~acent the ~L3tal end 2~3 o:l' the cover converge in a genera].:Ly conlcal shape toward the distal end Or the cover to an lnslcle dlameter sma:L:Ler than the diameter of' the cylindr:Lca:L sensor :L~ IG. 4).
As can best be seen in FI~. 3) when the probe shaf't 16 ls :Lnserted lnto the cover 12 for mountlng of the cover on the shaft, the sensor 1~ ls forced into the converglng conlcal walls 30 o~` the cover, thereby de-flecting a portlon of the conLca]. wall radially outwardly, as can be seen at 32 in FICT. 3. :~y this arrangement, the cover 12 will tlghtly engage the temperature sensor 14 for retaining the cover on the shaft while providing positive conkact with the sensor to ensure an adequate . and predlctable path for communication of heat to the sensor.

7;~
g As previously indicated, the temperature sensing probe 10 and disposable cover 12 of` the present inven-t~on are part-lcularly adapted for use with electronic thermometer lnstrumentation. Such instrumentation may be of the type whlch requ~res a precisely defined thermo-dynamic environment in the region of the temperature sensor 14 in order to provide accurate temperature readings, particularly where the instrumentation uses some form of extrapolation to speed up temperature read-10 ings on an approximation basis In this connection, lnorder to provide accurate and reliable temperature measure-ments, the portion of the cover 12 which is arranged to tightly surround the sensor 14 at the temperature senslng tip of the probe shaft 16 is preferably con-15 structed to have a predetermined and carefully con-trolled thickness and thermal conductivity to cooper-ate with the electronlc instrumentation with which the cover and probe 10 are ultimately used. Further, it will be noted that the cover 12 tlghtly surrounds and engages the sensor 14 around its cylindrical surface to provide a positive path ~or conduction of heat to the sensor without requiring that the sensor actually contact the inslde of ~e distal. end ~ of the cover.
To provide the desirecl c:ont;ro:L Or wall th:lckness and therma:L concluctlvltyJ the cover :l.2 13 prererably molded as a un:l.tary pl.e(e of. a h:L~h denslty polyethyl-ene material In addltiorl l;o :l~s ai)lllty ~o be molded to wlthln sati~ actoIy to:l.erances and the provislon of adequate therma:l conductiv:Lty, this pre~erred mater-lal ig ~u.t~:L`icl.ent:l.y reailient t,o elas-tlca.lly cle~`orm and engage the tenlperature ~ensor :l.l~, and provides a lightweight and attractive cover whlch ls relat-lvely inexpensLve to manu:i.`acture Moreover, thi~ partLcular mater-lal is suf`fic:lently rigid to permL~ eJectlon from the probe ~haft 16 by the plns 26, as will be described in greater detall below. Of course, any suitable material can be employed for con~tructing the unitary cover 12, but the above-mentioned high density poly-ethylene is the presently preferred materlal.

..

~.5~
--10~
Xn orcler to arrange the cover 1~ to be releas~
ably secured to the probe 10, the length of the cover is dlmenslonecl so that theproximal end 20 of the cover abuts a shoulder 34 on the handle 22 when the sensor 14 is ln tight engagement wlth the conical ~Jall 30 ad~acent the distal end 28 of the cover. By this arrangement, the distal end of the cover cannot be damaged by lnsert-ing the probe shaft 16 too far into the cover and causing the sensor 14 to break through the conical wall 30. It will also be noted from FIG. 3 that the prox-lmal end 20 of the cover 12 is dimensioned to fit loosely over an enlarged proxlmal end 36 of the probe shaft 16 so that the cover is retained on the shaft 16 solely by the res-llient engagement of the conical wall 30 on the sensor 14. Further, the pins 26 are recessed withln the apertures 27 in the shoulder 34 and are movable forwardly, in response to depressing the eJectlon button 24, to engage the proximal end 20 of the cover and urge the cover forwardly out of engagement 20 with the sensor 14.
The cover 12 of the present invention can also be used with an alternative embodiment ar a temperatur~
senslng probe 40 (:L~I~. 5). In this embodiment, the probe 40 Ls ent.l.re;l.y self-conta:l.ned, having an internal 25 power source 42, 5uch as a batter~, and temperature measurlng :~nst,r~lnelltation 4l~ ) to pI;OV:~e a di~ital readout; 1l`~; or other su:l.tab:le tcmperature ln-dication 'I'he probe 40 has a prol)e ~llaf.`t which i~ covered 30 b~ the cover :l2, anfl the cover :Ls retained on the shaf't ln the same manner as descrlbe(:3 above. To eJect the cover 12 rrom the~ probe shaft, a movable member 4~
(FIG. 6) is moun~ed on the probe 40 adJacent the proxi-mal end of the cover and includes an e~ection button 35 50 at the rear~ard end thereor. The movable member 48 operates in response to depressLng the button 50, and abuts the proximal end of the cover urging the cover out of engagement with the probe shaft.
In a preferred embodiment of the probe 40~ and 7~

as can best be seen in :F~G. 6, the button 50 is re-slliently biased toward -l~s depressed position by a light spring 52, and the button is held in its un~
depressed posit-lon against the urging c~ the spring 52 by the engagement of the proximal end of the cover 12 against the movable e~ection member 48. In order to ensure that the temperature measuring instrumentation 44 is energized only when a cover 12 is properly in place on the probe sha~t, a conventional on-off switch 54 operatively engages the movable ejection member 48 and is arranged to complete a circuit connecting the power source 42 to the lnstrumentation 44 only when the e~ection member is moved rearwardly by the engagement of the proximal end of a cover 12. In the absence of 15 a cover 12, the spring 52 holds the e~ection member 48 in the position illustrated dlagrammatically in FIG~
; 6~ in which position the switch 54 is open, and the power source 42 is dlsconnected from the temperature sensing instrumentation 44.
From the foregoing, lt wlll be appreciated that the temperature sensing probe 10 and probe cover 12 of the present invention are of rugged, reliable and econ-omica~. construction, and ideal t;hermal contact 's pro-vided between the unltary probe cover 12 and the ~ensor 14 at the temperature sen~Lng t;ip oi` the probe shaft 16, so that consiatently accurate and reliable trans-ducer input to the e:Lectrica:l l;hermometer instrumenta-tion is assure~i 'L'h~ probe 10 ancl probe cover 12 are relatively inexE)ellslve to malluiact;llre~ and the probe cover ls caL~able oi eas~ :Ln~t,a:l.lat;:Lon and removal w:Lth-out requlrlng d.l.rect physlca.l. contact wlth a human oper-ator. ~Ience, t;h~ problenls o:C ster:Lll~ation and re-distribut:l.on are avo:Ldecl, and problems of infection and cross-contamlnat:Lon are minlmi~ecl.
While part:Lcular forms oi` the invention have been illustrated and described, it w~ll be apparent that various modificat;lons can be made without departing from the sp-lrit and scope of the invent;ion.

Claims (6)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A temperature sensing device including a sensing probe and a removable probe cover, said device comprising: an elongated probe shaft having a temper-ature sensor at a distal end thereof and being rigidly secured to a handle at a proximal end thereof; and a substantially rigid tubular cover, separate from the structure defining said probe, said cover having an open proximal end adjacent said handle and a closed distal end in tight engagement with said temperature sensor, whereby said cover is releasably mounted on said probe by said tight engagement of said cover on said sensor;
said device further characterized in that said handle includes a movable means for engaging the proximal end of said cover and urging said cover away from said handle and toward the distal end of said probe shaft, and said movable means is movable between a first position toward said distal end of said probe shaft and a second position away from said distal end, and wherein said handle in-cludes means for resiliently biasing said movable means toward said first position, said movable means being held in said second position, against the urging of said biasing means, by the tight engagement of said cover on said sensor.

2. A temperature sensing device set forth in Claim 1 wherein said handle includes a means for acti-vating and deactivating said temperature sensing device, said activating and deactivating means being responsive to said movable means whereby said temperature sensing device is deactivated when said movable means is in said first position and activated when said movable means is in said second position.

3. A temperature sensing probe for use with an ejectable probe cover, said probe comprising:
a probe handle adapted for manual manipulation of said probe; an elongated probe shaft having a proximal end rigidly mounted to said handle and having a distal end including a temperature sensor arranged to releasably retain said cover on said shaft; and means on said handle for engaging a proximal end of said cover when said cover is mounted on said probe, said means being selectively movable between a first position retracted toward said handle for retaining said cover on said shaft and a second position extended toward said distal end of said shaft for ejecting said cover from said shaft, and further including means for resiliently biasing said movable means toward said second position, said movable means being held in said first position, against the urging of said biasing means, by the engagement of said proximal end of said cover when said cover is retained on said probe by said temper-ature sensor.

4. A temperature sensing probe as set forth in Claim 3 wherein said handle includes a means for activating and deactivating said temperature sensing probe, said activating and deactivating means being responsive to said movable means whereby said temperature sensing probe is activated when said movable means is in said first position and deactivated when said movable means is in said second position.

5. A self-contained temperature sensing probe for use with an ejectable probe cover, said probe comprising:
an elongated probe shaft having a proximal end and a distal end, said distal end including a temperature sensor arranged to releasably retain said cover on said shaft; and a housing adapted for manual manipulation of said probe and rigidly mounted on said proximal end of said prove shaft, said housing including an internal source of power, tem-perature measuring instrumention, a switch connecting said source of power to said temperature sensing instru-mentation, means for indicating the temperature sensed, and movable means for engaging a proximal end of said cover and urging said cover away from said housing toward the distal end of said probe shaft, whereby said cover will become disengaged from said sensor and be ejected from said probe shaft, and said movable means being movable between a first position toward said distal end of said probe shaft and a second position away from said distal end, and said housing including means for resiliently biasing said movable means toward said first position, said movable means being held in said second position, against the urging of said biasing means, by the reten-tion of said cover on said sensor, said housing further including an ejection button operatively connected to said movable means for moving said movable means toward said first position, thereby ejecting said cover from said probe shaft.

6. A self-contained temperature sensing probe as set forth in Claim 5 wherein said movable means is oper-atively connected to said switch so that said switch oper-ates to connect said source of power to said temperature sensing instrumentation when said movable means is in said second position, and said switch operates to discon-nect said source of power from said temperature sensing instrumentation when said movable means is in said first position.