Note: Descriptions are shown in the official language in which they were submitted.
BACKGROUND OF TEIE INVENTION
Various probe covers are in use for the purpose of preventing
contamination when the probe is reused. These prior art probe covers
, normally incorporate some type of outer jacket which is at least partially
removed to expose a protected inner sheath. The sheath covers the
', probe in use such as during insertion of a thermometer into a pa~ent's
mouth. Prior art probe covers have generally utilized layers of
bonded plastic strips. The strips are bonded along their longitudinal ~`
edges to produce a tubular inner sheath into which the temperature probe ~ `
, is received. To provide for relative ease of insertion, the tubular sheath
is made of substantially a greater diameter than the largest temperature probe
", contemplated for use w~ith the sheath. Such a configuration produces a
relat1vely 1006e relationship between the temperature p~be end and the
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inner sheath, such that less than a fully desirable thermal conductivity
is produced in that the plastic material is not drawn tautly over the
temperature probe end. Further, upon removal of the temperature probe,
; the sheath remains extended with its contaminated outer surface exposed.
In the disposal of the probe cover, then this outer sheath may contact the ;~
user or other articles and thereby ultimately contaminate other patients.
It is therefore desirable to have a temperature probe cover that
enhances the thermal conductivity between the temperature probe end and the
surrounding environment, and which facilitates the sanitary disposal of the
contaminated probe cover. Such a device is particularly desirable where it
is adaptable to a wide range of temperature probe end sizes.
The invention relates to a method of manufacturing probe covers
for temperature probes, and is specifically described in association with '~
glass and liquid thermometers. ~owever, it is to be understood, that the
principles of the invention are equally applicable to the probe covers in
any application where it is desired to cover the probe with a disposable
sheath of sheet metal.
The specific probe cover is described more fully in applicants
previously filed patent application entitled TEMPERATURE PROBE COVER, now
' 20 issued as United States Patent No. 3,809,228 dated May 7, 1974. The f" "
i principles of the invention are applicable to all probe covers incorporating ~.
`' a tubular inner sheath, whether formed from flat sheet stock, tubular stock
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Accordingly the method of the invention consists of a method of
manufacturing probe covers, the probe covers comprising layers of heat bond~
able sheet material, to obtain an elongated sheath with an openable end and
a closed end, and having a probe end engagement section adjacent the closed ;; end that engages the probe end during probe removal to turn said sheath
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inside out comprising the steps of: placing layers of sheet material on a
platen, pressing a welding head incorporating a heated shoe onto said sheet / -
material and bonding said layers together to form a tubular probe cover j!~.,,'; ' . "
sheath having a generally triangularly shaped bonded area adjacent the `
closed end of the sheath, said step of pressing said heated shoe is
characterized by a pressure gradient which generally increases with width-
~ise distance, from the longitudinal edges of said probe cover sheath. -
In the preferred probe cover described heArein, there is an
elongated inner sheath formed of plastic sheet material. Two layers are ;
utilized. The!layers are sealed together along their longitudinal edges.
The sensing end of the sheath is either sealed or folded over thus ~orming
an inner sheath which is sealed on three sides. The fourth side may either
be sealed with severable seal or left open. The term "Openable" as used in
the specification and claims is intended to cover both such configurations. -
~; 20 The sealed inner sheath forms a tubular sheath with a width, along the
major portion thereof, greater than the maximum width of the preselected
temperature probes to be utilized with the probe covers. Adjacent the
sensing end of the inner sheath there is provided a reduced width probe-end `
engagement section. The section is configured to produce a cooperative i~
1 engagement between the probe, and probe end engagement section9 and in the i
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exemplary embodiment takes the form of bonding the plastic layers together
to produce a restricted tubular section adjacent the sensing end. The
bonded area extends across only a portion of the sensing end of the inner `
sheath and is tapered at an angle to the longitudinal axis of the inner
sheath so that larger probe ends engage the section in advance of the point
at which smaller probe ends engage the section. Thus, the capability of
handling a range of probe end sizes is enhanced. The bonded area has a
graduated bond strength which generally increases toward the width-wise
outer edge o~ the tubular inner sheath. In the generally triangularly shaped
bonded area incorporated in the exemplary embodiment, this width wise increase
in bonded strength results in a triangular area with maximum bond strength ~`
at the apex of the triangle spaced the maximum distance from the inner sheath
sensing end. The bond strength is gradually reduced along the side of the ~`-
bonded area toward the sensing end. Accordingly, when the temperature probe
is inser~ed into the inner sheath and forced into the probe end engaging
section, the plastic material will begin to be drawn around the temperature '`~
probe end. The force of insertion will cause the weaker portions of the
banded area to-become severed permitting adequate plastic material to admit ,
the temperature probe end fully into the desired sensing area. When fully ``
~ 20 inserted the temperature probe end is engaged about its circumference fully
¦ by the plastic material which is stretched taut and in contact with the
temperature probe end. Upon completion of the temperature sensing operation ~ ~ ^
the temperature probe is drawn through an outer jacket portion adhered
opposite the openable end of the inner sheath. The sensing end of the
inner sheath is, by its engagement with the temperature probe end, drawn
inside out such that the contaminated outer surface becomes the inner surface
in a complete inversion of the inner sheath. When the temperature probe is ~`
completely withdrawn the user grasping the uncontaminated outer sheath is
` able to throw the temperature probe cover away without contacting the con-
', 30 taminated surface. -
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The bonded area of the probe end engaging section is formed with
jl the use of a welding shoe. The welding shoe produces the weld by a com-
; bination of heat and pressure applied to one side of the outer sheath. The
other side of the outer sheath is supported on a platen of resilient
material such as rubber. The weld shoe has a taper, such that the portion
oE the bonded area which is to have the maximum strength bond are pressed
with the highest pressure, and those areas which are intended to have a
relatively weak bond have a minimum applied pressure.
It is an object of the invention to provide a new and improved ,
temperature probe cover method of manufacture. `
I Other features and advantages will become more apparent upon a
reading of the following detailed description together with the drawings in
uhich like reference numerals refer to like parts throughout and in which~
i Figure 1 is a top plan view of a complete cover, partially cut
I away.
¦ Figure 2 is an enlarged sectional view~ taken on line 2-2 of the ;~
~ Figu~e 1.
i~ Figure 3 is a sectional vie~ taken on line 3-3 of Figure 2.
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Figure 4 is a sectional view taken on line 4-4 of Figure 2.
Figure 5 is a top plan view showing the initial stripping of the
outer jacket after insertion of thermometer.
Figure 6 illustrates ~he inner sheath being turned inside-out by
removal of the thermometer.
Figure 7 is an enlarged view of the end of the inner sheath with
a large bulb thermometer inserted.
Figure 8 is a similar view showing an alternative engagement
J section arrangement. .
Figure 9 is a similar view of a further engagement section
arrangement.` ,`
Figure 10 is a perspective view showing the initial steps of the ~
forming of the inner sheath. ``
`', Figure 11 is a side elevation view partially cut away of the ``
apparatus for welding the bonded area of the engagement section.
~ Figure 12 is an underside view of the welding head.
!~ Figure 13 is an enlarged sectional view taken on line 13-13 of
~ Figure 12.
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Figure 14 is an enlarged sectional view taken on line 14-14 of
Figure 11.
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Referring now to the drawings, there`is illustrated in Figures
1-6 a dispo~able temperatwre probe cover according to the invention.
The probe cover comprises an outer jacket 10 and an inner sheath 12.
The outer jacked includes a severable portion 14 and a probe insertion
portion 16. Probe insertion portion 16 is formed with an opening 18 which - `:
it shares with the inner sheath 12. The outer jacket is scored along
line 20 and notched at 22 and 24 so that it may be parted along line 20
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to expose the inner sheath 12. The inner sheath is formed of plastic ; -
layers 60 and 62 and has an open end 28, and a closed or sensing end 30.
10 A tubular sheath portion 32 is formed between the longitudinal seals 34 y
and 36. The full width of the tubular sheath portion 32 is available for
insertion of a probe such as the thermometer 38 in Figure 5. A probe
end engagement section 41 comprises a reduced width of the tubular
sheath portion 32 adjacent the closed or sensing end 30 formed by a
15 bonded area 40. The bonded area 40 is generally triangular in its
configuration and is defined by the bond line 36 on one edge and the bond
line 42 along the opposite edge. The bond line 42 initially angles sharply
toward the center of the in}ler sheath tubular section 32 and then tapers at
a somewhat lesser angle over the remainder of its length, terminating
20 at the closed or sensing end 30 in the inner sheath. The bond strength
of the bond line 42 is graduated from a maximum at the bond line 36 to
a minimum at the terminal end of the bond line 42 at the sensing end 30
of the inner sheath 12.
The layers 60 and 62 within the bond lines 36 and 40 in this
25 embodiment are unbonded or have minimal strength bonds for purposes
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to be described more fully hereinafter. However, it is also possible to
;i produce a continuous bond across the entire area 40, which bond has a bond
strength that tapers from a maximum along bond line 36 to a minimum
with widthwise distance from bond line 36.
For relatively small probe end sizes such as is illustrated for the
thermometer 38 in Figure 5, a relatively small portion of the bond line -~
42 is separated by the force of insertion of the temperature probe end.
j The plastic material isi~tretched taut over the temperature probe end and
'i creates an intimate contact with the temperature probe end to maximi~e
thermal conductivity. In the case of the insertion of a relatively large
temperature probe end, such as the probe end illustrated for thermometer'
46 in Figure 7, a greater portion of the bond line 42 is parted so that the
relatively large temperature probe end of the thermometer 46 is
accommodated without failure of the plastic material.
The action of the probe end engagement section 41 upon withdrawal
of the temperature probe 38 is illustrated in Figure 6. The inner sheath
12 has been drawn through the outer sheath jacket insertion section 16 and
is drawn inside-out~ such that the contaminatéd outer surface of the inner
~` sheath is the inner surface of the inverted inner sheath. The inversion `
'~ 20 continues untll the inner sheath 12 is completely inside-out, and the
temperature probe end is released by the engagement section. The probe
cover is then discarded.
Referring now to Figures 8 and 9, two modified configurations
, for the temperature probe engagement section are illustrated. In
Figure 8 the engagement section comprises two bonded areas 50 and 52
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extending from the bond lines 34 and 36. The angulated bond lines 54 and , ;
56 have a graduated bond strength which decreases towards the closed end 30.
In Figure 9 a bond area 58 extends from the bond line 34 partially across
the tubular inner sheath 32. The bond strength for the section 58 graduates
from a maximum adjacent the bond line 34 to a minimum at its terminal
portion 60. ~,
Referring now to Figures 10-13, the method for manufacture of the
improved temperature probe cover is illustrated. The plastic layers 60 and
62 are illustrated as comprising a folded portion of a single layer of sheet
material. The layers are folded over guide fingers 64 on the assembly- `
conveyor system. Bond lines 34 and 36 and the welded section 40 are made
around the guide fingers 60 so that thereafter the guide fingers serve to
support the inner sheath for further processing. The bond lines, and
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bonded area 40 are made by a welding head 66 which applies heat and pressure
to the plastic material. For this purpose the plastic material is brought
over a rubber platen 68 which is protected by a Teflon* release sheet 70. ~ -~
The rubber platen 68 distributes the weld pressure evenly and translates ,`~
the weld head taper into a pressure variation as will be described more fully
hereinafter. The general configuration for the weld head is illustrated in ~;r'' ''
Figure 12 which shows a pressure rib 72 corresponding to the bond line 34,
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pressure rib 74 corresponding to the bond line 36, and pressure rib 76
corresponding to bond line 42. Rib 76 is tapered in height along its length `~from the point where it joins the rib 74 to its terminus. The tapered edge `~78 is most apparent in the illustration in Figure 13. Figure 14 illustrates
the effect of the taper !
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in the bonding process. The ribs 72 and 74 are illustrated pressing
the plastic layers 60 and 62 into the rubber platen 68. The rib 76 is
illustrated at a section substantially mid-way along its length. Thus the rib
76 is significantly shorter than the corresponding portion of the rib 74
and 72 therefore presses the layers 60 and 62 into the platen a lesser
extent. This results in a lower bonding pressure and therefore a lower
bonding strength. It will be noted that the area defined by the ribs 74
and 76-includes a central area 80 with no pressure ribs. Thus little or
no bonding action is developed in the corresponding area of the sheath
12. The unbonded area produces a sheath which avoids the rigidity
that~would result from an excessively large bonded area. Additionallly,
the use of two pressure ridges rather than a surface area welding head
eliminates excessive head buildup, and the attendant possibility of burn
through in the plastic material.
O PERA TION
In use, the nurse or other user inserts the thermometer 38 through
' the open end of the outer jacket 10 and inner sheath 12. The thermometer
38 passes along the inner sheath and engages the probe end engaging
section 41. The bond line 42 forces the thermometer bulb 39 to one side
of the inner sheath 12, in a narrowing funnel configuration~ whereupon
the thermometer bulb encounters a tubular width of the inner sheath
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that is less than the bulb dimensions. This causes a resilient stretching
of the plastic and a partial permanent deformation thereof so that the
plastic sheath completely conforms to the outer surface of the bulb 39. ` '
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25 When the bulb penetration reaches a point that the plastic stretch and
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and deformation can no longer accommodate bulb movement, the graduated ~
bond along the line 42 begins to part making additional plastic availa~e ,
while maintaining an intimate contact with the bulb 39. The removable
portion of the outer jacket 14 is then removed by twisting it about the i `
5 part line 20 and withd rawing it as is illustrated in Figure 5. The
thermometer 38 and sheath 12 are then inserted into the patient's mouth,
for example. The plastic ta~ness over the bulb 39 insures good thermal ;
conductivity to produce a proper temperature reading in a minimum time.
When the thermometer is removed from the patient's mouth,the nurse
grasps the thermometer with one hand and the outer jacket portion 16 ` ~ `
with the other and withdraws the thermometer in the manner illustrated 5' ' ': "
in Figure 6, causing the inner sheath to be turned inside-out such that
the contaminated outer surface becomes the inner surface and none of the '
contaminated portion of the sheath is subject to being touched by anyone `~
15 or coming in contact with other objects. The nurse then disposes of the
probe cover by dropping it into appropriate disposal container, and then ~;
reads the temperature on thermometer 38. '
Having described our invention, we now claim.
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