U.S. patent number RE34,599 [Application Number 07/856,718] was granted by the patent office on 1994-05-03 for disposable probe cover assembly for medical thermometer.
This patent grant is currently assigned to Diatek Incorporated. Invention is credited to Richard P. Meyst, Edward D. Suszynski.
United States Patent |
RE34,599 |
Suszynski , et al. |
May 3, 1994 |
Disposable probe cover assembly for medical thermometer
Abstract
A probe cover assembly for use in covering and protecting the
elongated probe of a medical thermometer. The assembly has three
laminated layers, including a flat base layer with an aperture
sized to slide over the probe, an intermediate stretchable film,
and a protective paper layer having radially-aligned perforations
aligned with the base layer aperture. In use, the probe cover
assembly is placed on the probe by inserting the probe through the
base layer aperture, from the assembly's paper layer side, to
stretch the plastic film over the probe, with the perforated paper
functioning initially to separate the probe from the film and
thereby prevent the film from initially sticking to the probe and
stretching unevenly. The probe cover assembly is removed from the
probe and discarded by sliding the apertured base layer along the
probe, with the perforated paper functioning to scrape the
stretched film from the probe. The probe cover assembly is
extremely compact and convenient to use, yet highly effective in
reliably covering the probe and facilitating an accurate,
repeatable measurement of a patient's temperature.
Inventors: |
Suszynski; Edward D. (Vista,
CA), Meyst; Richard P. (Valley Center, CA) |
Assignee: |
Diatek Incorporated (San Diego,
CA)
|
Family
ID: |
23010811 |
Appl.
No.: |
07/856,718 |
Filed: |
March 25, 1992 |
Current U.S.
Class: |
374/158; 206/306;
374/209; 600/474; 600/549 |
Current CPC
Class: |
G01J
5/021 (20130101); G01J 5/02 (20130101) |
Current International
Class: |
G01K
1/08 (20060101); G01K 001/08 () |
Field of
Search: |
;374/158,209 ;206/606
;128/664,736 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
0044791 |
|
Jun 1982 |
|
EP |
|
0015647 |
|
1902 |
|
GB |
|
90/5902 |
|
May 1990 |
|
WO |
|
Primary Examiner: Cuchlinski, Jr.; William A.
Assistant Examiner: Gutierrez; Diego F. F.
Attorney, Agent or Firm: Pretty, Schroeder, Brueggemann
& Clark
Claims
We claim:
1. A disposable probe cover assembly for an elongated, generally
cylindrical probe of a medical thermometer, comprising:
a thin, flat base having a generally circular aperture sized to
slide over an elongated, generally cylindrical probe of a medical
thermometer;
a stretchable plastic film; and
a protective layer;
wherein the base and protective layer are laminated to opposite
sides of the plastic film, with the portion of the protective layer
that is aligned with the base aperture being perforated;
wherein the cover assembly can be placed on the elongated probe by
inserting the probe through the base aperture, from the protective
layer side of the assembly, to stretch the plastic film over the
probe, the perforated protective layer functioning initially to
separate the film from the probe and thereby prevent the film from
initially sticking to the probe and stretching unevenly;
and wherein the cover assembly can be removed from the elongated
probe by sliding the apertured base along the probe, the perforated
protective layer functioning to scrape the stretched film from the
probe.
2. A disposable cover assembly as defined in claim 1, wherein the
stretchable plastic film and the thin, flat base are both formed of
polyethylene.
3. A disposable cover assembly as defined in claim 1, wherein:
the stretchable plastic film is substantially transparent to
infrared radiation.
4. A disposable cover assembly as defined in claim 3, wherein the
stretchable plastic film is formed of a linear, low-density
polyethylene, with a uniform unstretched thickness in the range of
0.0005 to 0.00125 inches.
5. A disposable cover assembly as defined in claim 1, wherein:
the protective layer is formed of a paper having minute structural
cavities; and
the base, plastic film, and protective paper layer are laminated to
each other sonically, with a portion of the base and plastic film
flowing into the minute structural cavities of the paper layer, to
secure the successive layers together.
6. A disposable cover assembly as defined in claim 1, wherein the
paper layer includes a plurality of radially-aligned perforations
spaced uniformly around the portion of the protective layer aligned
with the generally circular base aperture.
7. A disposable cover assembly as defined in claim 1, wherein the
cover assembly is substantially flat prior to its use in covering
the elongated probe of the medical thermometer.
8. A disposable cover assembly as defined in claim 7, wherein:
the cover assembly has a substantially square periphery; and
the cover assembly is attached, via opposite sides of its
substantially square periphery, to a plurality of additional,
substantially identical cover assemblies.
9. A disposable probe cover assembly adapted for use with an
infrared sensitive medical thermometer having an elongated,
generally cylindrical probe sized to fit within a patient's ear,
the assembly comprising:
a stretchable plastic film substantially transparent to infrared
radiation;
a thin, flat base layer laminated to one side of the plastic film,
the base layer having a generally circular aperture size to slide
over an elongated, generally cylindrical probe of an
infrared-sensitive medical thermometer; and
a protective layer laminated to the side of the plastic film
opposite the base layer, with the portion of the protective layer
that is aligned with the base aperture including generally
radially-aligned perforations;
wherein the probe cover assembly can be placed on the elongated
probe by inserting the probe through the aperture of the base
layer, from the assembly's protective layer side, to stretch the
plastic film over the probe and thereby prevent contaminants from
moving between a probe and the patient's ear, the perforated
protective layer functioning initially to separate the film from
the probe and prevent the film from initially sticking to the probe
and stretching unevenly;
and wherein the assembly can be removed from the elongated probe by
sliding the base layer outwardly along the probe, with the
perforated protective layer functioning to scrape the stretched
film from the probe surface.
10. A disposable probe cover assembly as defined in claim 9,
wherein:
the base layer is formed in a high-density polyethylene material,
with a uniform thickness of at least about 0.010 inches; and
the stretchable plastic film is formed of a linear, low-density
polyethylene material, with a uniform thickness in the range of
0.0005 to 0.00125 inches.
11. A disposable probe cover assembly as defined in claim 9,
wherein:
the protective paper layer is formed of a paper having minute
structural cavities; and
the base layer, plastic film, and protective paper layer are
laminated to each other sonically, with a portion of the base layer
and plastic film flowing into the minute structural cavities of the
protective paper layer, to secure the successive layers
together.
12. A disposable probe cover assembly as defined in claim 9,
wherein the protective layer includes a plurality of
radially-aligned perforations spaced uniformly around the portion
of the protective layer aligned with the generally circular base
aperture.
13. A disposable probe cover assembly as defined in claim 9,
wherein the probe cover assembly is substantially flat prior to its
use in covering the elongated probe of the medical thermometer.
14. A disposable probe cover assembly as defined in claim 13,
wherein:
the probe cover assembly has a substantially square periphery;
and
the probe cover assembly is attached, via opposite sides of its
substantially square periphery, to a plurality of additional,
substantially identical cover assemblies.
15. A disposable probe cover assembly adapted for use with an
infrared sensitive medical thermometer having an elongated,
generally cylindrical probe sized to fit within a patient's ear,
the assembly comprising:
a stretchable plastic film formed of a linear, low-density
polyethylene material, with a uniform thickness in the range of
0.005 to 0.00125 inches, the film being substantially transparent
to infrared radiation;
a thin, flat layer sonically welded to one side of the plastic
film, the base layer being formed in a high-density polyethylene
material, with a uniform thickness of at least about 0.010 inches,
and having a circular aperture sized to slide over an elongated
cylindrical probe of an infrared-sensitive medical thermometer;
and
a paper layer sonically welded to the side of the plastic film
opposite the base layer, with the portion of the paper layer that
is aligned with the base aperture including a plurality of
uniformly-spaced, radially-aligned perforations;
wherein the probe cover assembly is substantially flat and can be
placed on the elongated probe by inserting the probe through the
aperture of the base layer, from the assembly's paper layer side,
to stretch the plastic film over the probe and thereby prevent
contaminants from moving between the probe and the patient's ear,
the perforated paper layer functioning initially to separate the
film from the probe and prevent the film from initially sticking to
the probe and stretching unevenly;
and wherein the assembly can be removed from the elongated probe by
sliding the base layer outwardly along the probe, with the
perforated paper layer functioning to scrape the stretched film
from the probe surface. .Iadd.
16. A disposable probe cover assembly for an elongated probe of a
medical thermometer having a remote end adapted for insertion into
a body cavity and an opposite base end, comprising:
a base layer having an opening defined therethrough the opening
sized sufficiently larger than the remote end of the probe so as to
fit easily thereover and sufficiently smaller than at least a
portion of the base end of the probe so as to engage the probe and
be retained at its base end in a fixed position; and
a stretchable plastic film extending across the opening defined
through the base layer, the film being affixed to the base layer
around the periphery of the opening, and the film further being
substantially flat prior to use in covering the probe,
wherein the probe cover assembly is configured to fit on the
elongated probe by inserting the probe's remote end through the
opening in the base layer to initially stretch the plastic film
evenly over the probe's remote end and by then sliding the base
layer along the probe to further stretch the plastic film until the
base layer is retained at the base end of the probe. .Iaddend.
.Iadd.
17. A disposable probe cover assembly as defined in claim 16,
wherein a rigid and fixed enlargement is formed at the base end of
the probe, the base layer is formed of a resilient material, and
the opening defined through the base layer is sized to snap over
the rigid and fixed enlargement at the base end of the probe.
.Iaddend. .Iadd.
18. A disposable probe cover assembly as defined in claim 16,
wherein the stretchable plastic film is substantially transparent
to infrared radiation. .Iaddend. .Iadd.19. A disposable probe cover
assembly as defined in claim 18, wherein the stretchable plastic
film is formed of a low-density polyethylene material. .Iaddend.
.Iadd.20. A disposable probe cover assembly as defined in claim 16,
wherein the stretchable plastic film is affixed to the base layer
by lamination to one side thereof. .Iaddend. .Iadd.21. A disposable
probe cover assembly as defined in claim 20, wherein the
stretchable plastic film is laminated to the side of the base layer
from which the probe is intended to be inserted. .Iaddend.
.Iadd.22. A disposable probe cover assembly as defined in claim 16,
and further including means for detachably connecting the probe
cover assembly along at least one of its edges to another,
substantially identical probe cover assembly. .Iaddend. .Iadd.23. A
disposable probe cover assembly as defined in claim 16, further
including a protective layer affixed to one side of the plastic
film, and wherein the probe cover assembly is detachably connected
via the protective layer along at least one edge of the protective
layer to another, substantially identical probe cover assembly.
.Iaddend. .Iadd.24. A disposable probe cover assembly for an
elongated probe of a medical thermometer having a remote end
adapted for insertion into a body cavity and an opposite base end
with a rigid and fixed enlargement formed thereon, comprising:
a flat base layer formed of a resilient material, the base layer
having a generally circular opening defined therethrough, the
opening being sized to fit over the remote end of the probe and to
be retained in a fixed position at the base end of the probe by a
snap fit over the rigid and fixed enlargement formed on the base
end of the probe; and
a stretchable plastic film formed of a low-density polyethylene
material that is substantially transparent to infrared radiation,
the plastic film extending across the opening defined through the
base layer and being affixed to the base layer around the periphery
of the opening, and the film further being substantially flat prior
to use in covering the probe,
wherein the probe cover assembly is configured to fit on the
elongated probe by inserting the probe's remote end through the
opening in the base layer to initially stretch the plastic film
evenly over the probe's remote end, and by then stretching the
plastic film along the probe by sliding the base layer until the
opening defined in the base layer snaps over the rigid and fixed
enlargement at the base end of the probe, the plastic film being
stretched longitudinally by an amount at least as great as the
diameter of the opening defined through the base layer. .Iaddend.
Description
BACKGROUND OF THE INVENTION
This invention relates generally to disposable assemblies for
covering the elongated probe of a medical thermometer, and, more
particularly, to assemblies of this kind that include a stretchable
plastic film.
Medical thermometers of this particular kind, which include
elongated probes adapted for insertion into various body cavities
(e.g., the mouth, rectum or ear canal), are the most commonly used
devices for measuring a patient's body temperature. Such
thermometers commonly include in the probe tip a thermistor or
infrared sensor to detect the temperature of the adjacent body
tissue.
The use of medical thermometers of this kind to measure the body's
temperatures of different patients raises a significant risk of
spreading infection and disease. To reduce this risk, such
thermometers are frequently used with hygienic probe covers that
are disposed of after each use.
To be effective, such probe covers must have sufficient strength to
withstand normal handling, including their placement on the probe,
and also must be configured to interfere minimally with the
sensor's (e.g., the thermistor's or infrared sensor's) temperature
detection. In the case of the infrared sensor, the thickness of the
portion of the probe cover located immediately in front of the
sensor must be highly uniform and must be controlled to a precise
tolerance.
It should, therefore, be appreciated that there is a continuing
need for a probe cover assembly for the probe of a medical
thermometer, which protects the probe and/or the patient from
contamination during its use, which provides a known minimum
interference with the probe's temperature sensor, and which is
durable, yet convenient to use and inexpensive to manufacture. The
present invention fulfills this need.
SUMMARY OF THE INVENTION
The present invention is embodied in a multi-layer, disposable
probe cover assembly for the elongated probe of a medical
thermometer, which is compact and convenient to use, yet interferes
minimally with the thermometer's temperature detection. The probe
cover assembly is simple to manufacture and compact for efficient
storage, yet highly durable, and ensures that cross-contamination
does not occur between the thermometer probe and the patient.
More particularly, the disposable cover assembly of the invention
has three separate layers laminated together, including a thin,
flat base layer, a stretchable plastic film, and a protective paper
or plastic layer. The base layer has a generally circular aperture
sized to slide over the elongated probe, and the base layer and
paper layer are laminated to opposite sides of the plastic film,
with the portion of the paper layer that is aligned with the base
aperture being perforated. In use, the assembly is placed on the
probe by inserting the probe through the base aperture, from the
paper layer side of the assembly, to stretch the plastic film over
the probe. During this stretching procedure, the perforated paper
functions initially to separate the probe from the film and thereby
prevent the film from initially sticking to the probe and
stretching unevenly. After the patient's temperature has been
measured, the cover assembly can be removed from the probe by
sliding the apertured base layer along the probe, with the
perforated paper functioning to scrape the stretched film from the
probe. This ensures that the cover assembly, including the
stretched film, will remain intact, for convenient disposal.
In a more detailed feature of the invention, the probe cover
assembly is specifically adapted for use with thermometers that
include an infrared sensor in or adjacent to its probe. The
stretchable plastic film is therefore constructed of a material
that is substantially transparent to infrared radiation, such as a
linear, low-density polyethylene. This material preferably has an
unstretched thickness of less than about 0.001 inches. The base
layer, plastic film, and paper layer are preferably laminated to
each other sonically. To facilitate such a sonic welding, the base
layer is preferably formed of a high-density polyethylene, and the
paper layer preferably has sufficient porosity to allow the base
layer and plastic film to flow into it, to secure the successive
layers together.
The perforations in the paper layer are preferably aligned
generally radially, such that pie-shaped wedges are defined between
them. Thus, upon insertion of the thermometer probe, the pie-shaped
wedges initially separate the probe tip from the stretching plastic
film, until the film has been stretched by more than the length of
the wedges. This prevents the film from sticking to the probe at a
point too early in its stretching, which could cause an uneven
stretch and lead to an unreliable temperature measurement.
In yet another feature of the invention, the probe cover assembly
is substantially flat prior to its use and it has a substantially
square periphery. In addition, the assembly can be attached, via
opposite sides of its square periphery, to a plurality of
additional, substantially identical cover assemblies. This
facilitates the use of a dispenser for automatically dispensing
individual probe cover assemblies during use of the thermometer
with multiple patients.
Other features and advantages of the present invention should
become apparent from the following description of the preferred
embodiment, taken in conjunction with the accompanying drawings,
which illustrate, by way of example, the principles of the
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side view of a medical thermometer having an elongated
probe sized to fit within a patient's ear canal and having an
infrared sensor for measuring a patient's body temperature, the
thermometer being depicted with a probe cover assembly embodying
the invention placed over the elongated probe.
FIG. 2 is a plan view of the probe cover assembly of FIG. 1, prior
to its placement on the thermometer probe.
FIG. 3 is a side view of the probe cover assembly of FIG. 2, with
the assembly's stretched configuration while in use covering a
thermometer probe being shown in phantom lines.
FIG. 4 is a side view of the probe portion of the thermometer of
FIG. 1, showing the probe cover assembly being ejected from the
probe
DESCRIPTION OF THE PREFERRED EMBODIMENT
With reference now to the drawings, and particularly to FIG. 1,
there is shown a medical thermometer 11 having an elongated,
generally cylindrical probe 13 adapted for insertion into a
patient's ear (not shown), with a disposable probe cover assembly
15 being used to cover the probe and thereby keep the probe
hygienic. The probe includes an infrared sensor within it, for
detecting infrared radiation being transmitted along the patient's
ear canal and thereby determining the patient's body temperature.
The probe cover assembly includes a stretchable film 17 that covers
substantially the entire probe, to protect contamination from being
transferred between the probe and the patient, yet that provides a
minimum, known effect on the transmission of infrared radiation to
the infrared sensor.
The probe cover assembly 15 is depicted in greater detail in FIGS.
2 and 3. The assembly has three laminated layers, including a base
layer 19, the stretchable plastic film 17, and a paper layer 21.
The base layer and paper layer are laminated securely to opposite
sides of the film. Prior to placement of the assembly over the
probe 13, the assembly is substantially flat, with a generally
square periphery. At this time, the paper layer functions
principally to protect the plastic film from damage during normal
handling and to interconnect the assembly with similar, adjacent
assemblies (not shown).
A circular aperture 23, which is formed in the middle of the base
layer 19, is sized to slide easily over the generally cylindrical
probe 13 of the thermometer 11. The portion of the paper layer 21
aligned with this aperture includes a plurality of perforations 25
oriented generally radially and spaced uniformly around the circle.
Generally pie-shaped wedges 27 are thereby defined between the
successive perforations.
The probe cover assembly 15 is placed over the probe 13 by pressing
the probe's remote end through the aperture 23 of the base layer
19, from the assembly's paper layer side. This stretches the film
over the probe, as shown in FIG. 1. During the initial stage of
stretching, the paper layer provides a skid surface of the probe
tip and the radial perforations 25 in the paper layer 21 assist in
centering the probe tip relative to the base aperture. In addition,
the paper layer separates the film from the probe tip until a
predetermined, minimum amount of stretching has occurred.
Consequently, the probe tip's initial contact with the film occurs
over the tip's generally circular periphery, which minimizes the
possibility of an uneven film stretch and the possibility of
localized tearing of the film.
With reference again to FIG. 1, it will be observed that the probe
cover assembly 15 is secured in place on the probe 13 by a snap-fit
of the aperture 23 of the base layer 19 over an enlargement 29
located at the probe's base end. .Iadd.As seen in FIGS. 1 and 3, at
this point the film 17 has been stretched longitudinally by an
amount at least as great as the diameter of the aperture 23.
.Iaddend.To remove the probe cover assembly from the probe after it
has been used to measure a patient's temperature, the base layer,
which is relatively more rigid than are the film 17 and paper layer
21, is pushed forwardly by a reciprocable cylindrical sleeve (not
shown), which is part of the thermometer 1. This sleeve can be
moved forwardly to a point where it projects beyond the probe's
remote tip, whereby the probe cover assembly can readily be
disposed of.
The pie-shaped wedges 27 formed in the paper layer 21 serve an
important function during the removal of the probe cover assembly
15 from the probe 13. In particular, and with reference to FIG. 4,
it will be observed that these wedges are interposed between the
probe 13 and the stretched film 17. As the reciprocating sleeve
pushes the paper layer 21 and thus the base layer 19 forwardly, the
wedges scrape the stretched film away from the probe surface and
thus prevent the film from sticking to the probe and becoming
inverted (like a stocking would become inverted during removal from
a foot if only the stocking's open end were to be pulled). This
feature ensures that the film will not remain stuck to the probe
even after the base layer and the paper layer have been pushed
beyond the probe's remote end.
With reference again to FIG. 3, the base layer 19, stretchable film
17, and paper layer 21 are laminated to each other using a
conventional sonic welding process. In this process, a high
frequency vibration is established in the three layers, which
causes the plastic base layer and film to fuse together and which
causes portions of the base layer and film to melt and flow into
minute cavities in the paper layer, thus securely holding the three
layers together. The effectiveness of this lamination process is
enhanced if a non-parchment-type paper with at least limited
porosity is used. In addition, using a conventional knurl to
locally concentrate or direct the sonic welding energy further
enhances the strength of the lamination.
Alternatively, the three layers, 17, 19 and 21 could be laminated
together using other conventional heat-sealing methods or using a
suitable adhesive. An adhesive approach is not preferred, however,
because of an expected higher manufacturing cost.
The base layer 19 and stretchable plastic film 17 will fuse
together most effectively if they are formed of similar plastic
materials. Preferably, the base layer is formed of a high-density
polyethylene material and the film is formed of a
puncture-resistant, linear, low-density polyethylene material. The
base layer has a thickness of at least about 0.010 inches,
preferably 0.012 inches, which provides it with sufficient rigidity
to allow convenient handling, but sufficient resilience to snap-fit
over the enlargement 29 at the base end of the probe 13 (FIG.
1).
The stretchable plastic film 17 preferably has an unstretched
thickness in the range of about 0.0005 to 0.00125 inches. This
unstretched thickness will allow the stretched film to have
sufficient strength to avoid puncturing and tearing yet to be
sufficiently thin to provide minimal absorption of infrared
radiation being transmitted from the patient's eardrum to the probe
sensor. The film is preferably stretchable substantially uniformly
in all directions. The film also can be coextruded with ethylene
vinyl acetate, for added strength.
The paper layer 21 can be a standard 0.005-inch lithographic paper.
Such a paper has the requisite porosity to facilitate the sonic
welding described above and also has the desired thickness and
resilience to isolate the stretchable plastic film 17 from the
probe 13. An excessive paper layer thickness should be avoided, to
prevent the possibility that the wedges might accidentally puncture
the plastic film. The paper also should have low linting
characteristics, to reduce the number of loose fibers being created
when the perforations 25 are being cut and when the assembly is
being placed on the probe 13.
With reference again to FIG. 2, it will be observed that the probe
cover assembly 15 has a generally square periphery. This is a shape
ideally suited to the manufacture of multiple side-by-side,
substantially identical assemblies. Such assemblies can be
connected to each other merely by the paper layer 21, which can be
perforated along the edges separating the assemblies, as indicated
by the reference numeral 33.
It should be appreciated from the foregoing description that the
present invention provides an effective probe cover assembly for
use in covering and protecting the elongated probe of a medical
thermometer. The assembly has three laminated layers, including a
flat base layer with an aperture sized to slide over the probe, an
intermediate stretchable film, and a protective paper layer having
perforations aligned with the base layer aperture. In use, the
probe cover assembly is placed on the probe by inserting the probe
through the base aperture, from the assembly's paper layer side, to
stretch the plastic film over the probe, with the perforated paper
functioning initially to separate the probe from the film and
thereby prevent the film from initially sticking to the probe and
stretching unevenly. The probe cover assembly is removed from the
probe and discarded by sliding the apertured base layer along the
probe, with the perforated paper functioning to scrape the
stretched film from the probe. The probe cover assembly is
extremely compact and convenient to use, yet highly effective in
reliably covering the probe and facilitating an accurate,
repeatable measurement of a patient's temperature.
Although the invention has been described in detail with reference
only to the preferred embodiment, those of ordinary skill in the
art will appreciate that various modifications can be made without
departing from the invention. Accordingly, the invention is defined
only by the following claims.
* * * * *