U.S. patent number 3,862,633 [Application Number 05/467,206] was granted by the patent office on 1975-01-28 for electrode.
Invention is credited to Kenneth C. Allison, William H. Cooley.
United States Patent |
3,862,633 |
Allison , et al. |
January 28, 1975 |
Electrode
Abstract
A biomedical electrode for use in cooperation with a
signal-receiving apparatus is the subject matter of this invention.
The instant electrode is one which is particularly adapted for use
in observing certain phenomena of the subject by observing
electrical signals one the surface of the subject. The electrode
includes an open-sided, resilient container, with a microporous
diaphragm closing the open side. An electrolyte is contained in the
container and permeates the diaphragm to unite with skin fluids of
the subject. The container contains a filling aperture on the side
opposite the open side. An annular sealing flange is formed
integral with the container and extends into the filling aperture.
A terminal plug is positioned in the filling aperture in sealing
engagement with the annular sealing flange to seal closed the
filling aperture.
Inventors: |
Allison; Kenneth C. (Crystal
Lake, IL), Cooley; William H. (Winneika, IL) |
Family
ID: |
23854807 |
Appl.
No.: |
05/467,206 |
Filed: |
May 6, 1974 |
Current U.S.
Class: |
600/392;
600/394 |
Current CPC
Class: |
A61B
5/25 (20210101); A61B 5/274 (20210101); A61B
2562/0217 (20170801) |
Current International
Class: |
A61B
5/0408 (20060101); A61B 5/0416 (20060101); A61b
005/04 () |
Field of
Search: |
;128/2.6E,2.1E,417,DIG.4 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Kamm; William E.
Attorney, Agent or Firm: Zummer; Anthony S.
Claims
What is claimed is:
1. A biomedical electrode for use on a subject for receiving
electrical signals from said subject, comprising: a resilient
container having an open side, a thin microporous diaphragm
sealingly secured to the container closing said open side, an
electrolyte in the container in contact with the diaphragm
permeating the diaphragm to wet the outside surface of the
diaphragm to have direct contact with the surface of a subject
through the diaphragm between the surface and the electrolyte in
the container, said container having a filling aperture, a
resilient annular sealing flange formed integral with the container
and extending inwardly to the filling aperture, and a terminal plug
mounted in said filling aperture in sealing engagement with the
annular sealing flange and having a portion in contact with the
electrolyte to form a half cell therewith, said terminal plug
locked in said filling aperture by said sealing flange, said
terminal plug including a head extending exteriorly of the
container, and a body positioned in the filling aperture and in
sealing engagement with the resilient annular sealing flange to
seal closed the filling aperture.
2. A biomedical electrode for use on a subject for receiving
electrical signals from said subject as defined in claim 1 wherein
the terminal plug is elongated, said head defines a portion of a
sphere and is adapted for connection to a lead for electrical
connection to an instrument, and a shoulder is formed integral with
said portion of a sphere; and said body includes a tapered shank
having its wider portion formed integral with the shoulder, a seal
face formed integral with the tapered shank adjacent to the
narrower end of said tapered shank, said seal face being adapted
for sealing engagement with the resilient annular sealing flange,
and a nose formed integral with the seal face and being adapted for
contact with the electrolyte, said nose having its free end rounded
to facilitate insertion of the terminal plug through the annular
sealing flange.
3. A biomedical electrode for use on a subject for receiving
electrical signals from said subject as defined in claim 2 wherein
the distance from the shoulder to the seal face is greater than the
length of the filling aperture but less than the length of the
filling aperture plus the width of the sealing flange, and said
diameter of the tapered shank adjacent to the seal face is greater
than the internal diameter of the annular sealing flange.
4. A biomedical electrode for use on a subject for receiving
electrical signals from said subject as defined in claim 1 wherein
the terminal plug is an elongated terminal plug, said head of the
terminal plug is adapted for connection to a lead for electrical
connection to an instrument, and said body includes a tapered shank
having its wider portion adjacent to the head.
5. A biomedical electrode for use on a subject for receiving
electrical signals from said subject as defined in claim 4 wherein
the body has a seal face formed integral with the tapered shank
adjacent to the narrower end of the tapered shank, said seal face
is adapted for sealing engagement with the resilient annular
sealing flange.
6. A biomedical electrode for use on a subject for receiving
electrical signals from said subject as defined in claim 1 wherein
the terminal plug has a connector receptacle for receipt of a
connector to make electrical contact therewith.
7. A biomedical electrode for use on a subject for receiving
electrical signals from said subject as defined in claim 6 wherein
the container includes a radial terminal groove in the side spaced
away from said open side for receipt of a lead.
8. A biomedical electrode for use on a subject for receiving
electrical signals from said subject as defined in claim 1 wherein
the head of the terminal plug is held in sealing engagement with
the container to form a seal therebetween, thereby forming a
secondary seal for the filling aperture.
9. A biomedical electrode for use on a subject for receiving
electrical signals from said subject as defined in claim 1 wherein
the terminal plug is an elongated terminal plug; said head of the
terminal plug is adapted for connection to a lead for electrical
connection to an instrument; and said body includes a tapered shank
having its wider portion adjacent to the head, a seal face formed
integral with the tapered shank adjacent to the narrower end of the
tapered shank, said seal face being adapted for sealing engagement
with the resilient annular sealing flange, and an elongated nose
formed integral with the seal face and being adapted for contacting
the electrolyte.
10. A biomedical electrode for use on a subject for receiving
electrical signals from said subject as defined in claim 1 wherein
the head is solid and has a rounded exterior, said body is threaded
over a portion of its length for threaded sealing engagement with
the resilient annular sealing flange to seal closed the filling
aperture, and the head sealingly engages the container to form a
secondary seal therewith for the filling aperture.
11. A biomedical electrode for use on a subject for receiving
electrical signals from said subject as defined in claim 1 wherein
the annular sealing flange is tapered and has its thinner portion
adjacent to the interior thereof, and said body is threaded for
threaded sealing engagement with the annular sealing flange.
12. A biomedical electrode for use on a subject for receiving
electrical signals from said subject as defined in claim 1 wherein
the annular sealing flange is tapered and having its thinnest
portion adjacent to the interior thereof, said head is solid and
has a rounded exterior surface, said head includes a tool recess in
its surface spaced away from the body for receipt of a tool for
rotating said plug, and said body is threaded over a portion of its
length for threaded sealing engagement with the resilient annular
sealing flange to seal closed the filling aperture.
13. A biomedical electrode for use on a subject for receiving
electrical signals from said subject as defined in claim 1 wherein
the container includes a radial terminal groove in the side spaced
away from the open side for receipt of a lead, said terminal plug
has a connector receptacle for receipt of a connector to make
electrical contact therewith, a flat head connector mounted in the
connector receptacle, and a lead electrically connected to the
connector and having a portion lying in the radial terminal groove
to provide a low profile for the biomedical electrode.
14. A biomedical electrode for use on a subject for receiving
electrical signals from said subject as defined in claim 1 wherein
the container includes a radial terminal groove in the side spaced
away from the open side for receipt of a lead; said terminal plug
has a connector receptacle for receipt of a connector to make
electrical contact therewith; said head of the terminal plug is
flat and adapted for engagement with the container; said terminal
plug body includes a tapered shank having its wider portion
adjacent to the head, a seal face formed integral with the tapered
shank adjacent to the narrower end of the tapered shank, said seal
face being adapted for sealing engagement with the resilient
annular sealing flange, and an elongated nose formed integral with
the sealing face and adapted for contacting the electrolyte; a flat
head connector mounted in the connector receptacle; and a lead
electrically connected to the connector and having a portion lying
in the radial terminal groove to provide a low profile for the
biomedical electrode.
Description
BACKGROUND OF THE INVENTION
The general construction of a biomedical electrode such as that
which is the subject matter of this invention is well-known in the
art and is disclosed in U.S. patent application Ser. No. 303,335,
filed on Nov. 3, 1972. The specific construction of such an
electrode is adequate for short-run production. However, when large
quantities of electrodes are required, the construction of the
electrode is such that it is difficult to fill the electrode
container with an electrolyte and then quickly and inexpensively
seal closed the container to retain the electrolyte in the
container.
SUMMARY OF THE INVENTION
The present electrode is a specific improvement of an electrode
which has a container having a permeable diaphragm on one side of
the container. The container is filled with an electrolyte through
a filling aperture. The container has an annular sealing flange
formed integral therewith and extending into the filling aperture.
Once the container is filled with electrolyte, a terminal plug is
inserted into the filling aperture and into sealing engagement with
the container and with the annular sealing flange to seal closed
the filling aperture. The terminal plug performs three functions in
the electrode. One function is to provide a terminal for connection
of the electrode to a lead; the second function is to seal closed
the filling aperture; and the third function is to provide the
necessary metal in contact with the electrolyte to form an
electrical half cell for operation of the electrode. It is
therefore a principal object of this invention to provide an
improved biomedical electrode construction, which electrode may be
quickly and easily assembled.
It is another object of the present invention to provide an
improved construction of a biomedical electrode in which the
various parts of the electrode may be quickly and easily
manufactured.
It is a still further object of the herein-disclosed invention to
provide a biomedical electrode which has a minimum of parts.
Other objects and uses of the instant invention will become readily
apparent to those skilled in the art upon a perusal of the
following specification in light of the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a biomedical electrode embodying
the present invention;
FIG. 2 is an enlarged cross-sectional view of the biomedical
electrode shown in FIG. 1, with portions broken away;
FIG. 3 is an enlarged side elevational view of a filling aperture
in a container of the electrode of FIG. 2, showing a terminal plug
in position for insertion into the filling aperture;
FIG. 4 is an enlarged cross-sectional view of the parts of FIG. 3,
but showing the terminal plug in its sealing position in the
filling aperture;
FIG. 5 is a cross-sectional view of a biomedical electrode similar
to that shown in FIGS. 1 and 2, but showing a modified container
and terminal plug construction;
FIG. 6 is a side elevational view of a connector which is
particularly adapted for use with the biomedical electrode shown in
FIG. 5;
FIG. 7 is a side elevational view of another form of connector
which may be quickly attached to a lead, which connector may be
used in connection with the biomedical electrode shown in FIG.
5;
FIG. 8 is a fragmentary cross-sectional view of a portion of a
container of a biomedical electrode having a slightly modified form
and a terminal plug particularly adapted for mounting in a filling
aperture of the container; and
FIG. 9 is a cross-sectional view of the parts shown in FIG. 8, but
showing the terminal plug positioned in a sealing attitude in the
filling aperture .
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings, and especially to FIG. 2, an
electrode which is a specific embodiment of the instant invention
is shown therein and is generally indicated by numeral 10. The
electrode generally includes a container 12 and a terminal plug 14
mounted in the container. A microporous diaphragm 16, made of a
thin sheet of plastic material, such as, polypropylene, is mounted
on the open side of container 12. The container is filled with an
electrolyte 18, which is an 0.25 percent sodium chloride solution
having a wetting agent, a bacteria inhibitor, and glycerine to
control evaporation. A mounting pad 20 is secured to the container
for attaching the electrode to a subject.
Container 12 is a resilient injection-molded part, which in this
instance is a polypropylene part, though any other suitable
material may be used. The container generally consists of two
integral parts, a cup 22 and a mounting flange 24. Cup 22 includes
an annular sloping wall 26, with a top 28 formed integral with the
smaller portion of sloping wall 26. A bead 30 is formed integral
with the outer periphery of the top 28. In the center of the top
28, there is a filling aperture 32, with a terminal boss 34 formed
integral with the top around the aperture 32. Formed interiorly of
filling aperture 32, there is a resilient annular sealing flange
36, having its outer periphery formed integral with the container.
Flange 36 extends inward of the sealing aperture for engagement
with the terminal plug 14, as will be described in detail
hereinafter.
Mounting flange 24 includes an annular cup flange 38, having its
interior formed integral with the lower portion of sloping wall 26.
A cylindrical wall 40 is formed integral with the outer periphery
of the flange 38. An annular pad flange 42 has its inner edge
formed integral with the cylindrical wall 40. An annular diaphragm
bead 44 is formed integral with an inner edge of the flange 38 for
receipt of the diaphragm. A sealing bead 46 is formed integral with
the outer edge of flange 38.
Mounting pad 20 is a thin piece of reticulated polyurethane foam,
in which there are 50 to 150 pores per linear inch. The pad had a
container aperture 48 receiving a portion of the container 12. A
network of adhesive 50 is placed on one side of the pad 20, with a
conventional release paper 52 positioned over the adhesive. The pad
20 is secured to the flange 42 by heat sealing. A conventional
sealing sheet (which is not shown herein) is mounted on the annular
bead 46 to prevent the electrode from drying out in storage.
However, when the electrode is in use, the sealing sheet is removed
from the bead so that the diaphragm may contact the surface of a
subject.
Terminal plug 14, in this instance, is a solid piece of tin-plated
brass. The plug generally consists of a connector head 56 and a
sealing body 58 formed integral with the head. The head includes a
spherical portion 60, with an annular shoulder 62 formed therein
and an annular fillet 64 between the portion 60 and the shoulder
62. The body includes a tapered shank 66 formed integral with the
shoulder and having a fillet 68 between the shank and the shoulder.
The body also includes a tapered nose 70 formed integral with the
shank 66. The nose 70 terminates in a rounded end portion 74. A
beveled seal face 72 is integrally formed between nose 70 and shank
66.
There is a very specific interrelationship of the sizes of the
terminal plug 14 and filling aperture 32 and sealing flange 36. The
diameter of the sealing shoulder 62 is greater than the diameter of
the filling aperture 32. The maximum diameter of the nose 70 is
less than the diameter of the filling aperture. The minimum
diameter of the tapered shank 66 is less than the diameter of the
filling aperture 32, but greater than the interior diameter of the
sealing flange 36. The distance from the shoulder 62 to the beveled
seal face 72 is slightly greater than the distance from the top of
the boss 34 to the bottom of the top 38, as viewed in FIGS. 2, 3
and 4, but less than the length of the filling aperture plus the
width of one side of the annular sealing flange 36. The length of
the nose 70 is slightly less than the height of the sloped wall 36,
for reasons which will become apparent hereinafter.
Electrode 10 is assembled by securing the diaphragm 16 to the
diaphragm bead 44 and securing the pad 20 to the flange 42. A
sealing sheet (which is not shown) is placed over the diaphragm,
into sealing engagement with bead 46. Cup 22 is filled with
electrolyte 18 through the filling aperture 32. Once the cup is
sufficiently filled, the terminal plug 14 is inserted into the
filling aperture to seal closed the filling aperture.
The terminal plug 14 is inserted into the filling aperture with the
longitudinal axes of the plug and the filling aperture being
aligned. The tapered nose 70 is inserted into the upper portion of
the aperture; and an axial force is applied to the plug so that the
rounded end portion 74 first engages the sealing flange 36. The
sealing flange 36, being resilient, is deformed by the rounded end
portion; and the outside walls of the tapered nose 70 then are
moved into engagement with the sealing flange 36. The sealing
flange is disposed downward as the tapered nose slides through the
sealing flange. The plug is moved downward until the sealing
shoulder 62 is placed adjacent to the upper surface of boss 34; and
the tapered nose, in its entirety, passes through the sealing
flange until the sealing flange engages the beveled seal face 72.
The diameter of the tapered shank 66 is greater than the diameter
of the aperture through the sealing flange, so that the sealing
flange is held downward in engagement with the seal face 72, thus
locking the plug in position, with the fillet 68 in sealing
engagement with the interior of the boss 34. It may be appreciated
that the fillet deforms the boss slightly so that there is a double
seal on the terminal plug.
There is one seal between the sealing flange 36 and the seal face
72, as may be best seen in FIG. 4. There is a secondary seal
between the fillet 68 and the upper portion of the boss 34. The
sealing action also serves to lock the plug into position, so that
the plug is held securely in place.
The nose 74 extends downward into the cup, toward the diaphragm 16,
but does not touch the diaphragm 16. However, the plug is immersed
in electrolyte 18. The terminal plug, having its nose tin-coated,
forms an electrical half cell with the electrolyte.
The electrode is applied to the skin of a subject by first removing
the sealing sheet from bead 46. The release paper 52 is also
removed from the pad. The electrode is adhesively secured to the
patient by positioning the electrode at a desired location and
applying a load to the mounting pad 20. Thus, diaphragm 16 is
placed into contact with the skin of a patient. The diaphragm 16,
being microporous, has electrolyte 18 permeating the diaphragm to
wet slightly the exterior surface of the diaphragm so that, as soon
as the diaphragm is placed into contact with a subject's skin, good
contact is made between the diaphragm and the subject's skin fluids
without the use of any other material or scraping the subject's
skin. As is conventional, a lead is attached to the terminal
plug.
Measurements are taken in a conventional fashion, using
conventional equipment. The electrical condition is observed on
electrical measuring equipment. There is a faithful reproduction of
a signal since there is ionic conduction through diaphragm 16 since
the electrolyte permeates the microporous diaphragm uniting with
the skin fluids providing a conductive path directly between the
electrode and the inner layer of the subject's skin. The amount of
noise and other electrical disturbances is held to a minimum,
thereby giving a high-fidelity signal.
The electrolyte is a physiological saline solution, thus allowing
the electrode to remain on a patient's skin for a prolonged period
of time. As the subject perspires, the perspiration does not affect
the operation of the electrode.
It is a simple matter to move the electrode by pulling the pad off
the skin of the subject. The electrode, being inexpensive to
manufacture, may then be discarded.
Another form of an electrode embodying the present invention is
shown in FIG. 5. The modified form of electrode is generally
indicated by numeral 100. The electrode 100 generally consists of a
resilient polypropylene container 102, a terminal plug 104 mounted
in the container, a microporous thin sheet polypropylene diaphragm
106 mounted on an open side of container 102, and a polyurethane
foam mounting pad 108 secured to the container. The container is
filled with an electrolyte 110, which is identical to electrolyte
18.
Electrode 100 is identical to electrode 10, except for the
construction of the container 102 and the terminal plug 104.
Container 102 generally consists of two parts, a cup 112 and a
mounting flange 114, which mounting flange is identical to mounting
flange 24. The cup 112 includes an annular sloping wall 116, with a
top 118 formed integral with the smaller portion of the sloping
wall 116. A terminal groove 120 is formed in the top 118. A
discontinuous bead 122 is formed integral with the top. The bead
122 is discontinuous only at the portion where the groove 120
extends through the bead. A filling aperture 124 is formed in the
center of the top, with a wall 126 forming a part of a terminal
portion adjacent to the groove 120. An interior boss 128 is formed
on the interior surface of the top, surrounding aperture 124. A
sealing flange 130 is formed integral with the boss 128 and extends
inwardly into the filling aperture.
The terminal plug 104 is a stamped brass hollow tin-plated plug,
which includes an annular head 132, with a hollow body 134 formed
integral therewith. The hollow body includes a shank 136, having
one end formed integral with the annular head 132. A seal face 138
is formed integral with one end of the shank. A hollow nose 140 is
formed integral with the face 138, and has a rounded end portion
142.
A lead wire 144 is connected to the terminal plug by a connector
146. The connector 146 includes a connector head 148 and a
connector body 150. The connector head has formed integral
therewith a conventional gripping portion 152. The connector body
150 has a conical connector shank 154, with a locking face 156
formed integral therewith and a connector snout 158 formed integral
with the face 156.
The electrode 100 is assembled in much the same manner that
electrode 10 is assembled. After the container 102 is filled with
the electrolyte 110, the terminal plug 104 is forced into the
filling aperture 124. The construction of the terminal plug is such
that the exterior diameter of the nose 104 is less than the
diameter of the filling aperture 124, but greater than the interior
diameter of the sealing flange 130. As the terminal plug is forced
into the container, the sealing flange is forced into the container
and outward. Then, when the nose passes entirely through the
sealing flange, the sealing flange engages the seal face 138 and
tends to push the plug into the container. However, the annular
head 132 engages the top 118 so that the terminal plug is held
securely in place. It follows that there are two seals between the
housing and the terminal plug. One seal exists between the sealing
flange 130 and the seal face 138. The second seal exists between
the annular head 132 and the top 118. The tin-plated nose 140 is
immersed in the electrolyte to form a half cell.
The electrode 100 gives a low profile in that the electrode does
not have its terminal plug extending upward and outward of the
electrode. The connector 146, which is electrically connected to
the terminal plug, also provides a low profile. It may be
appreciated that the connector 146 is connected to the terminal
plug by inserting its connector body 150 into the terminal plug and
snapping the connector body in so that the face 156 engages the
interior of the seal face 136, while the connector head 148 is in
engagement with the annular head 132. The gripping portion 152 and
the lead 144 lie in the groove 120, so that the overall height of
the connector positioned in the electrode is not substantially
higher than the electrode.
Other forms of connectors may be used with the electrode 100, such
as those shown in FIGS. 6 and 7. A button connector 160 is shown
connected to a lead 162. The button connector has a conventional
head 164, with a plurality of spring legs 166 formed integral with
the head. The lead 162 has a wire 168 soldered to the head 164. The
connector 160 is snapped into the terminal plug 104 by positioning
the spring legs 166 into the opening of the terminal plug and
pushing the button downward so that the spring legs engage the
interior surface of the nose 140 to make contact. A solderless
connector 170 is shown in FIG. 7. The solderless connector has a
head 172, with an elongated ribbon portion 174 formed integral with
the head. The ribbon portion has a pair of clamping arms 176 and
178 for engagement with the lead. The head 172 has a plurality of
spring legs 180 formed integral therewith, which spring legs also
fit into the aperture of the terminal connector. Whether connector
160 or 170 is mounted in electrode 100, each provides a low
profile.
Irrespective of which connector is used with the electrode 100, the
electrode operates in the same manner as the electrode 10, which is
described in detail above.
Another improved electrode construction is shown in FIGS. 8 and 9.
Only a portion of a top 200 of a container, with a terminal plug
202, is shown therein inasmuch as the remainder of the electrode is
identical to electrode 10. The top 200 has a filling aperture 204;
and a boss 206 is formed integral with the top. Adjacent to the
interior surface of the top, there is an annular tapered sealing
flange 208 extending inwardly of the filling aperture. The terminal
plug 202 includes a head 210 and a threaded body 212. The head 210
includes a generally spherically shaped portion 216, having a
conventional tool recess 214, for receipt of a tool (in this
instance, an Allen wrench). Head 210 also includes a shoulder 218
formed integral with portion 216, with a fillet 220 therebetween. A
fillet 222 is formed at the junction of the shoulder and the
threaded body. The terminal plug is, in this instance, made of
tin-plated brass.
Terminal plug 202 is inserted into filling aperture 204 after the
container has been filled with electrolyte. Terminal plug 202 is
positioned in the filling aperture and then turned with an
appropriate instrument positioned in recess 214 until the threads
pass through sealing flange 208. The plug is rotated until the
bottom of shoulder 218 engages boss 206 and fillet 222 deforms the
boss slightly so that there is a seal between the upper surface of
the boss 206 and fillet 222. The filling aperture is completely
sealed by the sealing flange 208 engaging body 212 and by the
engagement of fillet 222 with boss 206. The operation of the
electrode is the same as that described in connection with
electrode 10.
Although a specific embodiment of the present invention has been
shown and described in detail above, it is readily apparent that
those skilled in the art may make various modifications and changes
in the specific disclosure without departing from the spirit and
scope thereof. It is to be expressly understood that the instant
invention is limited only by the appended claims.
* * * * *