CA1106641A - Temperature sensing probe and disposable cover therefor - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

This invention relates to a cover for an elongated temperature sensing probe of an electronic thermometer having a movable collar and an elongated probe terminating with a probe tip including a heat sensing element. The disposable cover has an elastic cylindrical side wall mounted on a closed end member is latched to the probe to enclose the tip and surround an elongated portion of the probe. The closed end member has a.
thin cone-shaped thermal window which is deformed into surface engagement with the probe tip when the cover is mounted on the probe. The thin thermal window merges into a closed blunt end having a thickness greater than the window. The probe collar and open end section of the cover have coacting releasable latch structure holding the cover in assembled relation with the probe.

Description

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This applicat:ion is a divisional of application serial number 272,882 filed March 1, 1977.
BACKGROIJND OF THE INVENTION
Covers for glass thermometers are disclosed by Govoni in U.S. Patent No. 2,768,736. These covers are elongated one piece -tubular members having closed ends adapted to Eit around the temperature sensing end of the thermometer. The wall of the cover is thin to allow rapid heating and heat transmission so that the thermometer can quickly reach its maximum temperature. Electronic 1~ clinical thermometers are equipped with elongated probes having temperature sensing elements. Disposable covers are releasably mounted on -the probes so that the thermometer can be used with a number of patients by merely replacing the cover. ~xamples of this type of probe and cover are shown in U.S. Patents Nos. 3,738,173 and 3,905,232. Tongret in U.S. Patent No.3,254,533 shows a disposable cover having an open end with an inwardly directed flange positioned over a base on the probe. The closed end of the probe has an aluminum tip for rapid transfer of heat to the temperature sensing element of the probe~ Oudewaal in U.S. Patent No. 3,822,593 discloses a disposable cover with a flexible elastic tip. A sleeve structure is used to mount the elastic tip on the end of the elongated tuhe. The elastic tip is adapted to be stretched over the end of the temperature sensing element of the probe. The tube has outwardly directed projections locatable in a groove in the collar to latch the cover on the probe. Another probe cover is disclosed by Naumann in U.S. Patent No. 3,880,282. This probe has a one-piece tapered hollow body having a small closed end. The wall thickness at the closed end is thin to allow relatively rapid heat transfer 3~ throu~h the material of the closed end.

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SUM~RY OF THE I~ENTION
The invention is directed to a cover for an electronic thermometer probe. The cover is a low cost disposable item and is effective in allowiny rapid transfer of heat from a body to the temperature sensing element of the probe. The temper~ture sensiny probe has an elongated -tubular member carrying a probe tip. The probe tip has a cone-shaped side wall surroundiny a tempera-ture responsive element, such as a thermistor, The side wall has a convex outside surface. A body is secured to the opposite end of 1~ the tubular member, providiny a passage for electrical conduc-tors which are connected to the thermistor. ~ cylindrical collar surrounds the body. A spring biases the collar over the body.
The collar has a head surrounding the tubular member. The head has an outwardly directed rib or shoulder. The shoulder forms part of a coacting releasable lock or latch s-tructure which re-leasably holds the cover on the probe. The cover is a dlsposable item having an elastic body or tube attached to a closed end member forming a cover chamber. The tubular probe member and tip are located in the cover chamber. The cover body has an open end having an annular bead surrounding the head to hold the body in assembled rela~ion with the tubular probe member and tip. The head forms an elastic second part of the coacting releasable latch structure that holds the cover on the probe. The closed end member has a cone-shaped thermal window section and a thicker blunt closed end or ront wall. The thermal window section has a thin flexible annular wall. The flexible wall is deformed or ~lexed into sur~ace engagemenk with the convex shape of the side wall of the probe tip so that heat is readily transferred through said thermal window section to the probe tip and temperature responsive element carried by the probe tip.

The cover has an elastic tubular body of plastic having i a yenerally cylindrical side wall surrounding a chaI~ber. A close-l end member is s~cured to one end of the tubular body. The otneL
end of -the body is open and has an annular bead. The end member has a thermal window section formed by a thin flexible annular wall to permit rapid heat transfe.r through the thermal ~7indow section~ The window section is yenerally cone-shaped and pre-ferably has a wall thickness in the range of .006 to .009 inch (.15 to .23 mm). The inside sur~ace of the thermal windo~J section tapers in a forward direction toward the closed end.
An object of the invention is to provide a low cost dis-posable cover or sheath for a temperature sensing probe that i5 safe, sturdy and reliable in use, can be sterilized, and is easily assembled and release~ from the probe. Another object of the invention is to provide a probe cover with an annular window section that can be located in deformed surface engagement with a probe tip having a temperature sensing element. A further object of the invention is to provide a probe cover and probe combination with releasable latch structure that ~ill hold the cover in operative relationship with the probe tip and can be readily re-

2~ leased from the probe. Another object o~ the invention is to provide a coacting latch structure between a probe and probe cover that re~uires an external positive force to separate the cover from the probe~ An additional object of the invention is to pro-vide a cover for a temperature sensing probe that is ecologically conservative as it is made with a minimum of material,by automatic machinery. Yet another object of the invention is to provide a cover for a temperature sensing probe that has a flexible body that can be easily deformed by the lips, gums or teeth of a patient. ~ still further object of the invention is to provide a ~ cover for a temperature sensing probe that has self ejecting or propelling behavior from the probe when released from the head.

These and additional objects, advantages and features of the temperature sensing probe and cover for the probe are set forth in the following descrip-tion and drawings.
IN THE DRAWINGS:
Eligure 1 is a side elevational view of a temperature sensing probe and disposable cover thereEor of the invention;
Figure 2 is a sectional view taken along line 2-2 of Figure l;
Figure 3 is an enlarged sectional view of the temperature sensing end of the probe and cover o~ Figure l;
Figure 4 is a sectional view taken along line 4-4 of Figure 3;
Figure 5 is an enlarged sectional view of the coacting releasable lock structure of the probe and cover;
Figure ~ is a sectional view taken alony line 6-6 of Figure l;
Figure 7 is a side elevational view of the disposable cover of the invention;
Figure 8 is a sectional view taken along line 8-8 of Figure 7;
Figure 9 is an enlarged sectional view of the closed end of Figure 7;
Figure 10 is a sectional view taken along line 10-10 of P'igure 9;
Fiyure 11 is an enlarged end view of the open end of Figure 7; and Figure 12 is an enlarged sectional view taken along line 12-12 G-f Figure 8.
DESCRIPTION OF PRP'F~RR~D EMBODIMENT

3~ Referring to the drawing, there is shown in Figures 1 an~
2 a temperature sensing probe assembly indicated generally at 20 6~

1 equipped with a ~isposable cover or sheath 21. The probe 20 is part of an electronic thermometer used orally or rectally by nurses, nurses aids, paramedics, physicians and veterinarians to read the temperatures of humans and animals. An example of an electronic thermometer having a digital readout is disclosed by Kauffeld and Holst in U.S. Patent No. 3,872,726.
Probe 20 has a cylindrical collar or sleeve 22 surrounding an elongated cylindrical chamber 23. A head 24 projects for-wardly from the collar 22. As shown in Figure 5, the forward end of head 24 has a cone-shaped converging nose 26 providing a tapered guide surface for the open end of cover 21. An outwardly directed annular shoulder or rib 27 is located rearwardly of the nose 26 and forms an annular recess or groove 28 with a shoulder 29 on the forward end of collar 22. Head 24 has a longitudinal axial passage 31 slidaly accommodating a tubular member 32. Member 32 is made of rigid material, as stainless steel tubing.
An elongated cylindrical bocly 33 is located in chamber 23.
Body 33 has a lon~itudinal passage 34 with a portion accommodating one end of tube 32 to connect the tube to body 33. Electrical conductors 36, as wires, are located in passage 34 and the passage of tube 32 to electrically couple a temperature or heat sensing element 48, as a thermistor, to the elec-tronic circuit of the thermometer. The forward part of body 33 has an enlarged out-wardly directed annular flange 37 and a front end carrying an annula~ washer or cushioning member 3~. Flange 37 is engaged by a coil spring 39 concentrically positioned abou-t body 33. The spring 3g en~ages an annular cap 41. Cap 41 has a center hole 42 which permits body 33 to project through cap 41. Collar 22 has an outwardly directed annular ring 43 having an axial flange 43A
surroundi.ng the cap 41~ The inside of flange 43A has an inclined or tapered annular surface which cooperates with the outer peri-pheral edge of cap 41 to hold the cap 41 in firm assembled engage-1 ment with ring 43. Preferably, the collar 22 and ring 43 are made of a one-piece plastic material which is rigid but which has sufficient elasticity to perrnit flange 43A to stretch so that the cap 41 can be removed ~rom ring 43. Ring 43 has a pair of holes 44, shown in Figures 2 and 6, which are used to accommodate a tool having fi.ngers which apply a longitudinal force to cap 41 to remove the cap from ring 43.
The outer end of body 33 is closed with a cup-shaped cap 45. Cap 45 has a side opening 45A providing an outlet for the con-ductors 36. The cap 45 is also a hand engaging member used inconjunctio~ with fingers in contact with ring ~3 to remove the cover 21 ~rom the probe 20.
Referring to Figures 2 and 3, tube 32 extends the length of cover 21 and is connected at its forward or right end to a coupling or probe insulator 46 of electrically and thermally in-sulative materia]., as a plastic such as polycarbonate. Coupling 46 has a longitudinal passage 47 for accommodating portions of conductors 36 that are connected to the temperature sensing element 48. A probe tip indicated generally at 49 is mounted on the forward end of coupling 46. Tip 49 has a generally flat, circular ~orward or closed end 51 having an inside surface in engagement with the temperature sensing element 48. Element 48 is secured to end 51 with a suitable material, such as solder or . the like. End 51 is integral with a cone-shaped side wall 52.
: Side wall 52 terminates with an inwardly directed ~lange 53 which fits into an annular groove 54 in coupling 46 to secure tip ~9 to coupling 46. The side wall 52 has an outside an.nul.ar surface or face 52~ having an out~7ardly curved or convex shape For - e~ample, the outer surace 52A of wall 52 has a 0.5 inch radius (12.7mm) normal to the longitudinal axis of the cone. Tip 49 is made o~ heat transmitting materi.al, such as silver or a li~e me~al.

eferring to Figures 7~ the probe cover or sheath ~l has an elongated hollow body or tube 56. Body 56 is a one-piece plastic tubular member having a thin cylindrical side wall and can be ma~e from polypropylene, polye-thylene and like plastics.
Body 56 is a flexible and elastic plastic and has a thin cylin-drical wall that can be longitudinally and circumEerentially stre-tched. The plas-tic is smooth and compatible with body tissue and resistant to body fluids. Body 56 has an open end 57 and an elongated linear passage or chamber 55. A tip or closed end 1~ member 58 is mounted on the forward end of body 56. Member 58 has a cylindrical open end section or tubular section 59 surrounded by the forward end 56A of body 56 and a longitudinal chamber 60.
Section 59 has a wall thic~ness of about .025 to .035 inch or .6 to .9 mm~ A pair of annular ribs 59A project outwardly from the outsid~ surface of section 59. End section 59 joins a middle section 61 having an annular shoulder 62 and a forwaxd tapered surface 63. Shoulder 62 provides a rectal insertion indicia or line indicating the proper rectal penetration position of the cover. The forward end of body 56 abuts against shoulder 62. As ~ shown in Figures 3 and 8, the outside diameter of sec~ion 59 is larger than the inside diameter of body 56 so that end 56A
is enlarged or stretched over section 59. The end 56A is in tight annular surface engagement with the outside surface of section 59 and its ribs 59A~ A heat seal or fuse 6~ permanently bonds and seals the end 56A to section 59 so.end member 58 cannot be removed from body 56 and prevents body fluids from flowing into cover chamber 55.
Referring to Figures 8 and 9, end member 58 has a generally flat transverss or blunt closed end or front wall 66 integral with an annular cone-shaped wall section 67. Wall 66 has a diameter of about half the diameter of the side wall 6~

1 56 of cover 21 and as best seen in Fig. 9, the blunt end 66 is appreciably thicker than the cone-shaped windo~ section 67. Section 67 has an inside cone-shaped surface 68. Surface 68 is straight Gr linear and convercJes in a forward direction -toward end 66. Pre-ferably, surface 68 is inclined at an angle of 16 rela-tive to the longitudinal axis of the chamber 60. This angle can range between 12 and 20. The wall section 67 is relatively thin as compared to the -thickness of section 59. Wall section 67 is elastic and flexible so that it can be stretched, distended o-. expanded over 1~ the probe tip 49. The material of section 67 has characteris-tics such that it does not deform or stretch beyond its elastic limit when the cover is in assembled relation with the probe. The elastic contracting force of the plastic of section 67 holds the inside surface 68 in firm and full surface engagement with the side wall 52A of the probe tip ~9. Preferably, wall sectlon 67 has a thickness of between .~06 and .009 inch, or .15 and .23 mm.
Section 67 has a wall thickness o~ about one-fourth the thickness of the side wall 59 of end member 58. The cone-shaped wall section 67 fo~ns an annular thermal window which is relatively ~O thin to permit con-trolled and efficient heat trans~er between the outside environment and the inside of the chamber 60. The thermal window is indicated at 69 in Figures 2, ~ and 9.
As shown in Figures 7, 8, 11 and 12, the end of body 56 surrounding the opening leading to the body passage 55 has an annular bead indicated generally at 71. The bead 71 is con-tinuous and has an inwardly directed rib or flange 72 and an outwardly directed rib or ~lange 73. The bead 71 functions to rein~orce the end o~ body 56 and acts as an elastic ring or garter that holds the cover in assembled relation ~ith the probe.
Bead 71 is part o~ the coacting latch structure that holds the cover 21 on probe 20.

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1 In use, probe 20 is coupled ~ia the electric line or cord 36 to the electronic thermometer an~ is a permanent and reusabl~
part of -the thenmometer. Cover 21 is a disposable item that has a single use In other words, after the temperature o-f a patient is monitored by the electronic tnermometer, the cover 21 is ejected Erom the probe 20 and a new cover is mounted on the probe for use with another patient.
A new cover is placed on the probe tube 32 by inserting the -tube 32 into the cover passage 55 through the open end 57.
The probe is moved into the cover 20 until the probe tip 49 is in full surface engagement with the inside surface 68 of the annular cone-shaped wall 67 and the annular bead 71 is located in the annular groove 28 behind shoulder 27. The collar 32 is moved toward the tip 49 to force -the annular bead 71 along nose 26 to the groove 28. The body 56 has sufficient strength so that the bead 71 rides up on the nose ~6 and circumferentially expands until the bead 71 is located in the groove 28. As soon as the bead 71 passes over the shoulder 27, it contracts so that the inner annular rib 72 is in annular engagement wi-th the shoulder 27. When the cover 21 is fully mounted on the probe 20, the cone-shaped outer wall 52A of the pro~e tip 49 is in full and firm surface engagement with the inside cone-shaped surface 68 of the wall section 67. Wall section 67 is slightly deformed outwardly into a convex shape as the cover 21 is pulled over the probe tip 49 to deform the relativel~ thin wall SectiQn 67.
This insures a uniform annular surface engagement over the length of the surface 52A of the probe tip 49 so that there is a controlled an efficient transfer of heat from the outside environ-ment to the probe tip 49. Spring 39 acting on cap ~1 and body 33 yieldably pulls cover 21 into engagement with the tip 49 to ma~in-tain the ful]., firm surface engagemen-t between the surfaces 3 52~ and 68, The elas-tic side wall 56 of cover 21 also functions as a biasing means or spring to bias the flexible ~Jall 67 of the thermal window section 69 into full surface engagement with the conve~ shaped side wall 52A of tip 49.
Cover 21 is released and removed from the probe by applying a compressive Eorce to spring 39. This is accomplished by gripping ring ~3 wi-th the first two fingers. The base of the thumb is placed against the end of cap 45. A squeezing force will compress spring 39 and provide relative movement collar 22 10 and tube 32. Thus, the head 24 and probe tip 49 are moved in opposite longitudinal directions. The relative movement between head 24 and probe tip 49 will elongate or stretch the elastic body 56 until sufficient force is developed to expand the annular bead 71 so that it will slip over the shoulder 27.
Once the annular bead 71 is free of shoulder 27 r the body 56 will re-turn to its non-stretched or original position. This provides the cover 21 with a reversing thrust or force so that it will propel itself from the probe tube 32. The operator can direct the cover 21 to an appropriate disposal container ~o without touching or handling the used cover.
While there has been shown and described a preferred embodiment of the temperature sensing probe and disposable cover for the probe, it is understood that changes in size, shape, structure and materials can be made by those skilled in the art without departing from the invention.

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Claims (19)

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

1. A cover for a temperature sensing probe comprising:
a flexible body having a generally cylindrical elastic side wall surrounding a chamber and having an end portion for closing one end of the chamber, said side wall having an open end section defining an opening into the chamber, and said end portion having an annular thermal window section having a flexible cone-shaped wall to permit rapid heat transfer through the thermal window section.

2. The cover of claim 1 wherein:
said thermal window section has a cone-shape and a wall thickness in the range of .007 to .009 inch.

3. The cover of claim 1 wherein:
said thermal window section has an inside conical surface tapering in a forward direction at an angle of between 12° to 20° relative to the longitudinal axis of the cover.

4. The cover of claim 1 wherein:
said thermal window section has a length of about .10 inch and a wall thickness in the range of .006 to .009 inch.

5. The cover of claim 1 wherein:
said open end section has an elastic bead.

6. The cover of claim 5 wherein:
said bead includes an inwardly directed annular flange.

7. The cover of claim 5 wherein:
said bead has an inwardly directed annular flange and an outwardly directed annular flange.

8. The cover of claim 1 wherein:
the end portion has a tubular section, said side wall of the body being positioned about said tubular section and secured thereto.

9. The cover of claim 1 wherein:
the end portion has outside means providing an indication of a rectal insertion position.

10. A cover for use with a temperature sensing probe having an elongated member, a tip secured to one end of the elongated member, said tip having a forwardly converging annular and relatively thin side wall, said side wall having an outward convex shape, a temperature responsive element secured to the tip means having a head surrounding the elongated member for holding the cover on the probe, said head having means cooperating with the cover to releasably latch the cover to the probe comprising: a tubular body having a generally cylindrical elastic side wall forming a chamber for accommodating part of the elongated member, and an end member secured to the body for accommodating the tip, said elastic side wall having an open end section having means engageable with the means on the head to releasably hold the cover in assembled relation with the elongated member and tip, said end member having a closed end and a forwardly converging annular relatively thin thermal window section adjacent the closed end, said closed end having a thickness greater than said window section, said window section having a flexible annular wall dimensioned to be deformed into closely fitting surface engagement with the convex shaped side wall of the probe tip when inserted therein whereby heat from the environment around the thermal window section is preferentially transferred through said thin thermal window section to the tip and the temperature

Claim 10 continued....

responsive element secured thereto, said elastic side wall being operable to bias the flexible annular wall into surface engage-ment with the convex shaped side wall of the tip, and wherein the dimensioning of said closed end including the said thickness thereof precludes significant heat transfer therethrough as compared to said annular thermal window section.

11. The cover of claim 10 wherein:
said thermal window section has a flexible wall having a thickness substantially less than the thickness of the side wall of the end member.

12. The cover of claim 11 wherein:
said flexible wall has a thickness in the range of 0.007 to 0.009 inch.

13. The cover of claim 10 wherein:
said thermal window section has an inside conical surface tapering in a forward direction at an angle of between 12°
and 20° relative to the longitudinal axis of the cover.

14. The cover of claim 10 wherein:
said means engageable with the means on the head includes an annular elastic bead.

15. The structure of claim 14 wherein:
said bead has an inwardly directed annular flange.

16. The structure of claim 14 wherein:
said bead has an inwardly directed annular flange and an outwardly directed annular flange.

17. The cover of claim 10 wherein:
the end member has a tubular section, said side wall of the body being positioned about said tubular section and secured thereto.

18. The cover of claim 10 wherein:
the end member has outside means providing an indication of a rectal insertion.

19. The cover of claim 10 wherein:
the end member has a front wall having a diameter of about half the diameter of the side wall of the cover.