CA1326797C

CA1326797C - Disposable speculum

Info

Publication number: CA1326797C
Application number: CA000508709A
Authority: CA
Inventors: Gary J. O'hara; David B. Phillips
Original assignee: Intelligent Medical Systems Inc
Current assignee: Covidien AG
Priority date: 1985-05-08
Filing date: 1986-05-08
Publication date: 1994-02-08
Anticipated expiration: 2011-02-08
Also published as: EP0201790B1; DE3688858T2; US4662360A; JPS61263438A; DE3688858D1; JP2537033B2; EP0201790A2; ATE93054T1; EP0201790A3

Abstract

DISPOSABLE SPECULUM

ABSTRACT

A sanitary protective cover or sheath for the ear canal probe of a tympanic thermometer has a generally tubular body portion and an infrared transparent membrane attached to and sealing the forward end of the tubular body portion. While the tubular body portion is being injection molded of a plastic material, a film of a similar plastic material is mated to the forward end of the tubular body portion. A
portion of the film defining the membrane is thus severed from the film and thermally bonded to the tubular body portion.

Description

- ~ 1 326797 DISPOSABLE SPECULUM

, 10 ~ BACKGRO~D OF THE INVENTIO~

.I The present invention relates to medical instrumen-.~ tation, and more particularly~ to a disposable cover or sheath for the probe of a clinical thermometer.
~ij .

. The ~iagnosis and treatment of many body a1lments depends upon an accurate reading of the internal or core . temperature o~ a patient's body, and in some instances, upon ~ 20 a comparison to a previous body temperature reading. For s . man~ years, the most conmon way o~ taking a patient's s, temperature involved the utilization of a Mercury . thermometer. ~his approach has a number of drawbac~s.

~,r~

"~ , : , .

' .

,.

1 ~26797 First of all, such thermometers are normally made of glass.
They must be inserted and maintained in the patient's mouth or rectum for several minutes, This is often discomforting to the patient. Furthermore, such thermometers can break, resulting in serious lacerations or Mercury poisoning. In addition, Mercury thermometers are difficult to read, must be sterilized, and must be "shaken down" vigorously to place the Mercury at the bottom end prior to use.

Because of the above drawbacks of conven~ional Mercury thermometers, electronic thermometers were developed and are now in widespread use. Typically, the commercialiæed versions of such elec~ronic thermometers have been designed for taking a patient's temperature orally or rectally. They have a probe connected by wires to a remote unit containing an electronic circuit. The probe is inserted into a protective, disposable plastic cover or sheath before being inserted into the patient's mouth or rectum. After the patient's temperature is taken, the sheath is discarded, and the probe is inserted into another sanitary sheath or takins the next patient's temperature. In this manner, the electronic thermometer is rapidly reusable with~ut communicatins infectious organisms between patients. The foregoing type of electronic thermometer typically uLes .. :

- 1 3 2 6 7 q 7 predictive techniques, by which the patient's temperature reading is taken in a significantly shorter time period, for example thirty seconds, compared to the several minutes required for the conventional Mercury thermometers. Such electronic thermometers normally have meters or other displays which enable the operator to determine the temperature much more readily than reading the position of the terminal end of a column of Mercury inside a glass tube.
The probe is typically an elongated rod of small diameter.
The sheath comprises a hollow tube having an open end and a closed, somewhat pointed end. It has a round cross-section of relatively small diameter and is made of a plastic material which is not toxic.
,~":
~ 15 The tympanic membrane is generally considered by the . .
medical community to be superior to oral, rectal or axillary sites for taking a patient's temperature. This is because the tympanic membrane is more representative of the body's internal or core temperature and more responsive to changes in core temperature. Heretofore, eforts to provide a method and apparatus for measuring the body temperature via the external ear canal have not been succe~sful. One approach has ~een to use a thermister, thermocouple or some other type of device requiring physica1 contact with the . .:

1 32679~

tympanic membrane. This approach is undesirable because of the discomfort to the patient and the dan~er of physical injury to the t~panic membrane Another approach has directed air against the tympanic membrane and a~tempted to measure the increase in temperature in returning air in order to derive the patient's temperature. Clearly thls approach has significant drawbacks in regard to accuracy.
` third and better approach to tympanic temperature measurement involves sensing infrared emissions in the external ear canal. In order to accomplish this ~ efficiently, a probe must be partially inserted into the ; external ear canal. A cover or sheath must be provided for enclosing the frontal portion of the probe -to present a clean, sanitary surface to the patient and also to keep the probe tip free of ear wax and hair. The probe cover or ; sheath must be made of material which is substantially , transparent to infrared radiation.

As used herein, the term "speculum" shall include any type o~ cover or sheath adapted to fit over a pro~e for the ~.
purpose just described. Preferably, such a speculum i8 inexpensive so that i~ can be disposed after a teMp~rature reading has been ~aken and a new speculum installed over the .:
..:

`'^

.

:~`

-; 1 326797 probe for the next patient. This eliminates any need to sterilize such speculums.

U. S. Patent No, 3,282,106 of Barnes sug~ests the concept of an infrared thermometer that may be placed in ~he e.ar cavity to measure body temperature. An infrared detector receives radiation through an internally polished , truncated cone which acts as a shield and which is partially inserted into the ear canal. This cone is apparently a permanent part of the apparatus and is not remo~able or disposable. The specification of the Barnes patent indicates that this cone was not intended to actually touch any portion o~ ~he outer ear. However, Barnes indicates that the cone may lightly touch portions of the outer ear because of lack of skill of the operator. Nevertheless, no protective speculum for the cone is disclosed in Barnes.
~ The aforementioned Barnes patent also discloses an alternate ; embodiment including a conventionally shaped ear plug which ~' contacts the external ear canal but is not provided with a speculum.
J ~;

- U. S. Patent No. 3,581,570 of Wortz discloses a tympanic temperature sensing device which has positioning means to esta~lish a fixed relationship between the eardrum , ;

..

and a radiometer. A polyethylene shield fits over the pro~e portion to pr~tect the radiometer. It does not appear that the shield is readily replaceable. Furthermore, the shield appears to be a cup-shaped member of uniform thickness. The very small width and length of the cup-shaped shield would make it very difficult to handle, install and replace.

U. S. Patent No. 3,878,836 of Twentier discloses a disposable speculum for an infrared sensing tympanic thermometer. This speculum has the general shape of a funnel and has open forward and rearward ends. The patent indicates that preferably the speculum is formed of polyethylene. The principal drawback of this speculum is that its open forward end which is partially inserted into , 15 the ear canal may become clogged with wax or other debris and impair proper functioning. ~lso, the open forward end will permit germs and other foreign matter to be transferred to the thermometer instrumen~ itself, thus presenting a risk of contamination and spreadiny of bacteria and viruses between patients~
~' ~

SUMMARY OF THE INVENTION

.. , i ~

: . :
..

~ `

`:

; 1 326797 Accoxdingly, it is the primary object of the present invention to provide an improved, disposable speculum.
.
It is another objec~ of the present invention to provide a disposable speculum for the ear canal probe of a tympanic thermometer.

Another object of the present invention is to provide a disposable speculum configured for easy mounting and removal from the instrument probe.

Another object of ~he present invention is to provide a ~ method o~ fabricating a disposable speculum uniquely suited i for an infrared body temperature measuring instrument.
Another object of the present invention is to provide a disposable speculum which acts a5 a sanitary barrier between a patient's ear canal and the sensing portion of an infrared sensitive tympanic thermometer which is partially inserted into the external ear canal after having the speculum mounted over the same.

The disposable speculum of the present invention comprises a sanitary protective cover or sheath for the ear . .
~ 7 ~ `

- 8~ - l 32 6797 canal probe of a tympanic thermometer. The speculum has a generally tubular body portion and an infrared transparent membrane attached to and sealing the forwaxd end of the body portion. While the tubular body portion is being injection molded of a plastic material such as polypropyl-ene or polyethylene, a film of a similar plastic material is mated to the forward end of the tubular body portion.
A portion of the film defining the membrane is thus severed from the film and thermally bonded to the tubular body portion.

The invention is directed to a disposable speculum for a probe of a tympanic thermom~ter, comprising: a substan-tially rigid body portion having an opening therein which is sized for receiving therethrough the probe; a thin film membrane of approximately uniform thickness attached around the periphery of the opening on one side of the body portion and extending across the forward end of the body portion; the body portion and the film membrane being ` 20 formed of a material selected from the group consisting of polypropylene and polyethylene; and the film membrane having a thickness selected to minimize attenuation of infrared radiation passing therethrouqh when stretched tight over the probe.
The invention is also directed to a method of fabri-cating a speculum for a probe of a tympanic thermometer comprising the steps of: injection molding a tubular body portion having an opening therein which is sized for receiving therethrough the probe formed of a first s~bstan-tially rigid plastic material; and bonding a membrane of a second pliant plastic material to a ~orward end of the tubular body portion, around the periphery of the opening, wherein the membran~ is formed by mating the forward end of the tubular body portion to a film of the second pliant plastic material while the tubular body portion is being molded so that a portion of the film is severed to form the - 8a ` l 326797 membrane and the membrane is thermally bonded to the - periphery of the opening of the tubular body portion, the film membrane having a thickness which minimizes attenu-ation of infrared radiation passing therethrough when ; 5 stretched over a probe.

BRIEF DESCRIPTION OF THE DRAWINGS
':
Fig. 1 is a side elevation view of the preferred embodiment of the disposable speculum of the present inven-tion.
.~
Fig. 2 is a longitudinal sectional view of the specu-lum of ~ig. 1 taken along line 2-2 of Fig. 1.

Fig. 3 is a lateral sectional view of the speculum of Fig. l taken along line 3-3 of Fig. l.
I "
~-~ Fig. 4 is a rear end elevation view of the speculum of Fig. l taken from the top of Fig. l.

~,, i .

j.
;,.

~, ~
."

!

I

' ,., , .

_ `~' ';',~

~ 1 326797 Fig. 5 is a front end elevation view of the speculum of Fig. 1 taken from the bottom of Fig. 1.

Figs. 6a, 6b and 6c are enlarged fragmentary views illustrating further details of the preferred embodiment of the speculum.
., , Fig. 7 is a gr~atly enlarged, longitudinal sectional view of the forward end of the speculum of Fig.
illustrating the thin film membrane bonded to the forward end of its generally tubular body.

Fig. 8 is a top plan view of a tree structure which carries a plurality of the disposable speculums o~ the type illustrated in Figure 1.
.
-. :
Fig. 9 is a cross-sectional view of the tree structure of Fig. 8 ~aken along line 9-9 of Fig. 8~
, .

~o Fig. 10 is a diagrammatic illustration of an apparatus '!` :
for molding the tubular body of the speculum of Fig. 1 and thermally bo~ding the thin film membrane to ~he forward end thereof.

, ., .

~ `

.~

^

DESCRIPTION OF THE PREFERRED EM~ODIMENT

Refexring to ~igs. 1 and 2, the preferred embodiment l0 of our disposable speculum includes a generally tubular body portion 12 and an infrared transparent membrane l4 attached to and sealing the forward end of the tubular body portion. The tubular body portion has a generally frusto-conical or truncated cone configuration. Its diameter gradually reduces from its rearward end to its forward end and includes several shoulders as explained hereafter in greater detail. The frusto-conical configuration permits the speculum to be partially inserted into the ear canals of both children and adults. The ; tapered configuration also enables the speculum to be snugly fit over and retained on the probe of a tympanic thermometer `~ instrument as explained hereafter in greater detail.
.
The speculum is preferably made of a non-toxic material ~- since it will come into contact with a patient's skin.
Also, the spesulum is preferably made of a material which is /
somewhat pliant. This allows the speculum to deform !` slightly to facilitate insertion into the ear c~n~l and also to squee~e fit over the instrument probe. ~iost ~mportantly, ,~
t '' ~, ~V

:
.

,-` t' 1 326797 the membrane 14 must be made of a material which is substantially transparent to infrared radiation, preferably in the seven to fifteen micron wavelength range, and more preferably substantially transparent to infrared radiation having a wavelength of approximately ten microns. Clinical data has confirmed that accurate in~ernal body temperature readings can be made by sensing infrared radiation at the foregoing wavelength which is emitted in the external ear canal.

Polypropylene and polyethylene are both plastic materials which are substantially transparent to infrared radiation at the foregoing wavelength. Of course the amount of attenuation of the infrared radiation passing through this material depends upon the thickness thereof.
~` Accordingly, the membrane 14 must be relatively thin to minimize the attenuation of in~rared radiation passing therethrough so that the tlle~-mopile or other detector receiving infrared radiation through the membrane will sense .
the maximum amount of infrared radiation available. This enhances the accuracy of temperature measurement. Also, the membrane should have a uniform thickness, with no wrinkles or other str~lctural characteristics that will distort the s ., infrared radiation passing therethrough. Such distortion can introduce errors in the temperature measurement process.

Accordingly, in the preferred embodiment of our speculum, the membrane 1~ (Fig. 7) which serves as the IR
window is made of polypropylene or polyethylene film having a maximum thickness of .001 inches, and pxeferably a thickness in the range of .OOOS to .001 inches. Preferably, the speculum will withstand approximately 1.2 PSI without rupturing. As explained hereafter in greater detail, the membrane 14 is thermally bonded to the forward end of the tubular body portion 12 and accordin~ly is able to withstand the 1.2 internal PSI.

The tubular body portion 12 tFig. 2) of the speculum need not be made of an infrared transparent material.
However, our speculum is moxe easily $ahricated and the bond ~ between the memhrane and the body portion is optimized, if ; both the membrane and the body portion are made of a similar plastic material. l'he body portion must be sufficiently ~ strong such that the speculum can be mounted over the probe, ; and removed from the probe~ without the operator havinq to touch tha speculum~ This ensuxes that the specul~n will be sanitary when it is introduced into the patient's ear eanal.

- 1 3267q7 Accordingly, the thickness of the walls of the body portion 12 must be chosen to provide sufficient structural integrity to permit the foregoing mounting and removal from the instrument probe. By way of example, where the body portion is made of polypropylene or polyethylene, a wall thickness of between approximately 0.01 to 0.02 inches is adequate.
., .
The tubular body portion 12 (Fig. 1) has a forward segment 12a, an intermediate segment 12b, and a rearward , 10 segment 12c, The forward end of the segment 12a is rounded to facilitate attachment of the membrane 14 as illustrated in Fig. 7. Four circumferentially spaced, longitudinally . extending flanges 16 ~Figs. 1,2 and 4) project outwardly from the rear end of the segment 12c. These may engage a support well (not illustrated) at their forward ends to aid :~ .
in holding the speculum stationary when the probe of the infrared thermometer is inserted into the speculum. Three circumferelltially spaced ears 18 (Figs. 1,2 and 3) project inwardly from the interior of the segment 12b and mate with corresponding detents in the thermometer probe (not .,1 ,~ illustrated) for retaining the speculum on the probe. The ~ ears 18 have a crescellt shaped configuration with a convex ,` surface as illustrated in the longitudinal sectional view of ;, ,:

:
:

Fig. 6a, horizontal sectional view of Fig. 6b~ and elevational view of Fig. 6c.

; ~y way of example, the outside diameter of the segment 12a of the tubular body portion may taper from an outside diameter of .314 inches immediately aft of the curved forward end thereof to an outside diameter of .329 inches at the rear end thereof. The segment 12b may extend at an an~le of approximately forty-five degreas relative to the inner wall of the segment 12a. The outside wall of the segment 12c may extend at an angle of five degrees relative to the central longitudinal axis of ~he speculum~ The tubular body portion 12 in its entirety may have a longitudinal dimension of .8 inches. The forward curved end of the segment 12a may have an outside radius of .055 inches. The ears 18 may project .010 inches into the ; interior of ~he speculum. Preferably both the inner and outer walls of the segments diverge gradually away from the ,~ central longitudinal axis of the speculum to f~cilitate a ~; 20 snug fit on the probe of the infrared ~hermometer.

To facilitate shipment and use, a plurality of the speculums may be connected in an array of rows and columns ,, .
~ by a tree structure 20 ~Fig, ~) of interconnected rails ~
:. ~
', 1~

. ' and side walls 24 (Fig. 9) made of the same plastic as the speculum body. Small integrally formed plastic extensions 26 (Fig. 9~ connect the tubular body portion of each of the speculums to the rails and side walls of the tree structure.
These extensions are adapted ~o be easily broken to individually release a selected one of the speculums upon a predetermined amount of force being applied to the one speculum in a direction away from the tree structure while the tree structure is held in a stationary position. ~he 1~ side walls of the tree structure may be supported in a housing of the thermometer as illustrated in U.S. Patent ; No. 4,602,642, granted July 29, 1986.
Each speculwn may also be seated in a corresponding well in the housinq having walls which engage and support the flanges 16 when the probe of the thermometer is inserted into the rear end of the speculum and pushed downwardly ~` toward the well. The speculum thus is squee~ed over theprobe and the ears 18 mate with the detents of the probe.
As this is done, the extensions 26 break. The probe can then be withdrawn and the speculum i5 retained tightly thereon. Preferably the body portion of the speculum mates with the probe so that the membrane is stretched tightly over the probe tip, thereby removing any wrinkles in the membrane. When the ears 18 mate with the detents of the `:

`I~

, probe, the membrane is held in tight, stretched fashion thereby preventing any wrinkles that would interfere with measurement accuracy~

.;
The most convenient way ~o fabricate the pref~rred embodiment of our probe would be to injection mold the ` entire speculum in one integral piece. However, with current plastic molding technology and apparatus, we have found it difficult to integrally mold the entire speculum with the walls and the membrane having thickness in the ranges described above. An unacceptable rate of defective speculums is encountered if the entire speculum is injection `~ molded as one in~egral coMponent.

~ 15 In order to oYercome the foregoing problem, we have s discovered that the preferred method of fabrication is to injection mold the tubular body portion and to affix a separate membrane to the frontal end of the body portion. A
film of a similar plastic material as the tubular body portion may be mated to the forward end of the tubular body portion while the tubular body portion is being injection ;:
molded, A portion of the film defining the membrane is thus .,,~
severed from the film and thermally bonded to the tubular ~ body portion. The strength of the thermal bond is greatly `` 16 .

``

,.:

enhanced if both the body portion and the film are made of the same material. This is because they will then have the same melting point.

The diagrammat~ic view of Fig. 10 illustrates the preferred method of fabricating our speculum. A male mold portion 28 and a female mold portion 30 are mounted for .. , mating engagement. A mandrel 32 of the male mold portion fits within a hole in the female portion to define a mold cavity 34 with the shape of the body portion of the speculum. Molten plastic is conveyed into the mold cavity ; 34 through passages such as 36 in the male mold portion.

As the molten plastic is being injected into the mold cavity 34, the joined male and female mold portions are moved against a web 36 of plastic film conveyed between supply and take-up rollers 38 and 40. The film is carried between the rollers 38 and 40 by a feed belt 42 driven around pulleys 44 and 46.
~0 After each speculum is formed, the feed belt 42, one leg of which is in contact with the rear side of the web 36 of film, is driven to advance a new section of the film downward into alignmant with the mandrel 32. Thereafter, . ~ .
~" ' `
. .

:

::

- `

the male mold portion 28 is inserted into the female poxtion 30 and mechanically driven against the stationary web 36 to the left as indicated by the arrow in Figure 10. At the same time a support block 48 may be mechanically driven to the left so that the web 36 and the feed belt 42 are squeezed between the opposing vertical faces of the female mold portion 30 and the support block 48. The feed belt 42 has a plurality of apertures spaced around its length as indicated by the dashed line in Figure 10. Before the mold portions and support block 48 are brought together, the feed belt 42 advances a new segment of the web 36 over the mandrel 32 and stops so that one of the apertures in the feed bel~ is aligned with the end of the mandrel 32. The aperture is also aligned with a hole 50 in the face of the i block 48 also in registry with the mandrel 32. l'he mold pOLtions and the support block are brought together and squeeze the web 36 and feed belt therebetween. Molten plastic introduced into the mold cavity 34 through the passage 36 and fills the mold cavity. The molten plastic which reaches the forward end of the mold cavity to the right in Figure 10 mat~s with the web or film 36, and severs a circular portion thereof which becomes the membrane 14.
,.~ The edges of this membran~ thermally bond to the rontal end ;~ of the molten tuhular body portion formed in the mold cavity ~, .
. .

.
~ .

"

~ 1 3267~7 34. The forward end of the mandrel 32 may extend slightly beyond the face of the female mold portion 30. This permits the forward end of the mandrel to press a circular portion of the film 36 through the aperture in the feed belt and into the hole 50 in the support block. This facilitates the severing action.

The mold portions and the suppoxt block may now be separated. When this occurs, the membrane of film 36 ,~ 10 remains attached to the forward end of the speculum now formed in the mold cavity 34. Thereafter, the male and female mold portions may be separated, freeing the now formed speculum from the mold. The feed belt 42 is then again energized to advance a new segment of the film 36 into position for joining the next body portion to be molded.

Details of the mold, wcb conveying and feed belt mechanisms have not been described as they will ~e apparent to those skilled in the art. Other mechanical arrangements 2G for accomplishing the foregoin~ method of abrication can be utilized, The entire tree structur~ and plurality of connected speculums illustrated in Fig. 8 may be ,~ simultaneously molded.
'`' ~.~

;~

~ 1 3267q7 Having described a preferred embodiment of the speculum, its method of fabrication and a readily useable connected array of speculums, it should be apparent to those . skilled in the art that our invention may be modified in both arrangement and detail. Therefore, the protection afforded our invention should only be limited in accordance with the scope of the following claims.
~' .

WE CLAI~:

~0

Claims

1. A disposable speculum for a probe of a tympanic thermometer, comprising:
a substantially rigid body portion having an opening therein which is sized for receiving therethrough the probe;
a thin film membrane of approximately uniform thickness attached around the periphery of the opening on one side of the body portion and extending across a forward end of the body portion;
the body portion and the film membrane being formed of a material selected from the group consisting of polypropylene and polyethylene; and the film membrane having a thickness selected to minimize attenuation of infrared radiation passing there-through when stretched tight over the probe.

2. A speculum according to claim 1 and further comprising means for establishing a predetermined longi-tudinal relationship between the body portion and the probe such that the film membrane is stretched over a forward end of the probe.

3. A speculum according to claim 1 wherein the film membrane has a maximum thickness of .001 inches.

4. A speculum according to claim 1 wherein the body portion has a tubular shape.

5. A speculum according to claim 4 wherein the tubular shaped body portion is formed with a plurality of circumferentially spaced, longitudinally extending flanges which project outwardly from a rear end of the tubular body portion.

6. A speculum according to claim 4 wherein the tubular shaped body portion is formed of an annular wall having a thickness of approximately 0.01 inches to 0.02 inches.

7. A speculum according to claim 4 wherein the tubular shaped body portion is formed with a plurality of inwardly projecting retention ears.

8. A speculum according to claim 4 wherein the forward end of the tubular shaped body portion has rounded edges.

9. A speculum according to claim 1 wherein the membrane is wrinkled before being stretched over the forward end of the probe.

10. A speculum comprising:
a generally tubular body portion having forward and rearward ends;
a membrane extending across the forward end of the tubular body portion, the membrane being substantially transparent to infrared radiation;
the tubular body portion and the membrane both being made of a pliant plastic material;
the tubular body portion being injection molded and the membrane being a film bonded to the forward end of the tubular body portion; and the film membrane being made of a stretchable plastic material and having a thickness chosen to minimize attenuation of infrared radiation passing therethrough yet being capable of withstanding approximately 1.2 PSI without rupturing or unbonding from the tubular body portion.

11. A speculum according to claim 10 wherein the membrane is made of a material substantially transparent to infrared radiation in the seven to fifteen micron wave-length range.

12. A speculum according to claim 10 wherein the plastic material is selected from the group consisting of polypropylene and polyethylene.

13. A speculum according to claim 10 wherein the tubular body portion is configured to mate with and enclose a probe so that the membrane is stretched over a tip of the probe.

14. A speculum according to claim 10 wherein the plastic material is selected from the group consisting of polypropylene and polyethylene and the membrane has a maximum thickness of approximately 0.001 inches.

15. A speculum according to claim 10 wherein the tubular body portion has a frusto-conical shape.

16. A speculum according to claim 3 wherein the frusto-conical shaped tubular body portion is formed with an exterior, forwardly facing shoulder.

17. A speculum according to claim 10 wherein the forward end of the tubular body portion has rounded edges.

18. A speculum according to claim 10 wherein the tubular body portion is formed of an annular wall having a thickness of approximately 0.1 to 0.2 inches and the membrane has a maximum thickness of approximately 0.001 inches.

19. A speculum according to claim 10 wherein the tubular body portion is formed with a plurality of reten-tion barbs.

20. A method of fabricating a speculum for a probe of a tympanic thermometer comprising the steps of:
injection molding a tubular body portion having an opening therein which is sized for receiving there-through the probe formed of a first substantially rigid plastic material; and bonding a membrane of a second pliant plastic material to a forward end of the tubular body portion, around the periphery of the opening, wherein the membrane is formed by mating the forward end of the tubular body portion to a film of the second pliant plastic material while the tubular body portion is being molded so that a portion of the film is severed to form the membrane and the membrane is thermally bonded to the periphery of the opening of the tubular body portion, the film membrane having a thickness which minimizes attenuation of infrared radiation passing therethrough when stretched over a probe.

21. A method according to claim 20 wherein the first and second plastic materials are the same.