U.S. patent number RE32,947 [Application Number 07/144,011] was granted by the patent office on 1989-06-13 for magnetic transcutaneous mount for external device of an associated implant.
This patent grant is currently assigned to Baptist Medical Center of Oklahoma, Inc.. Invention is credited to Kenneth J. Dormer, Gordon L. Richard.
United States Patent |
RE32,947 |
Dormer , et al. |
June 13, 1989 |
**Please see images for:
( Certificate of Correction ) ** |
Magnetic transcutaneous mount for external device of an associated
implant
Abstract
Disclosed is a transcutaneous coupling apparatus comprising a
first member subcutaneously positioned in a user of the invention
and also comprising a second member positioned supercutaneously, or
outside the skin of the user. Rare-earth magnets are associated
with the first and second members to magnetically secure the second
member with the first member without significantly adversely
affecting the user's skin intervening between the first and second
members.
Inventors: |
Dormer; Kenneth J. (Edmond,
OK), Richard; Gordon L. (Minco, OK) |
Assignee: |
Baptist Medical Center of Oklahoma,
Inc. (Oklahoma City, OK)
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Family
ID: |
26841600 |
Appl.
No.: |
07/144,011 |
Filed: |
January 14, 1988 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
Reissue of: |
192480 |
Sep 30, 1980 |
04352960 |
Oct 5, 1982 |
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Current U.S.
Class: |
607/57; 600/13;
600/12 |
Current CPC
Class: |
A61N
1/37223 (20130101); A61N 1/375 (20130101); A61F
2250/0001 (20130101); A61N 1/36038 (20170801) |
Current International
Class: |
A61F
2/02 (20060101); A61N 1/372 (20060101); A61N
1/375 (20060101); A61F 011/00 () |
Field of
Search: |
;128/1R,1.5,420.5,420.6,12,13,15 ;381/68,68.3 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
"Magnetic Materials as Biological Implants--Criteria for
Selection," by Jack Driller et al., 1973. .
"Cochlear Implant Utilizing Rare Earth Magnets", Dormer et al, Am.
Jrnl. Otology, vol. 2, #1, 7/1980. .
"Magnetic and Physical Properties of Commercially Available Rare
Earth-Cobalt Permanent Magnets," by H. F. Mildrum et al., 1974.
.
"Cochlear Implants," by William F. House, M.D., printed in The
Annals of Otology, Rhinology & Laryngology, May-Jun., 1976.
.
"Neural Prostheses," by F. Terry Hambrecht, printed in Ann. Rev.
Biophys. Bioeng., 1979. .
"Rare Earth-Cobalt Magnets in Modern Medicine," by G. Hennig, H.
Feustel and K. Hennig, 1975. .
"Magnetic Continent Colostomy Device," by J. Alexander-Williams et
al., printed in British Medical Journal, May, 1977. .
"Nonsuture Microvascular Anastomosis Using Magnet Rings:
Preliminary Report," by Yoshiro Obora, M.D. et al., Surg. Neurol.,
vol. 9, Feb. 1978. .
"Preliminary Experience with Lid Magnets for Paralytic
Lagophthalmos," by E. N. Hinzpeter et al..
|
Primary Examiner: Smith; Ruth S.
Assistant Examiner: Lacyk; John P.
Attorney, Agent or Firm: Laney, Dougherty, Hessin &
Beavers
Claims
What is claimed is: .[.1. A transcutaneous coupling apparatus,
comprising:
a first member positioned subcutaneously;
a second member positioned supercutaneously; and
magnet means for magnetically securing said second member to said
first member..]. .[.2. An apparatus as defined in claim 1, wherein
said magnet
means includes a rare-earth element..]. 3. .[.An apparatus as
defined in claim 1, wherein:
said first member includes electronic means for receiving an
electrical signal; and.]..Iadd.A transcutaneous coupling apparatus,
comprising:
a first member positioned subcutaneously;
a second member positioned supercutaneously; and
magnet means, cooperating with said first and second members, for
magnetically securing said second member to said first member; and
wherein .Iaddend.
said second member includes electronic means for .[.transmitting
the electrical signal.]. .Iadd.generating an electromagnetic
transmission to activate electrical conduction in said first
member; and
said first member includes electronic means, responsive to said
electromagnetic transmission, for electrically stimulating
subcutaneous
tissue.Iaddend.. 4. An apparatus as defined in claim 3, wherein
said
magnet means includes a rare-earth element. 5. .[.An apparatus as
defined in claim 1, wherein:.]. .Iadd.A transcutaneous coupling
apparatus, comprising:
a first member positioned subcutaneously;
a second member positioned supercutaneously; and
magnet means, cooperating with said first and second members, for
magnetically securing said second member to said first member; and
wherein .Iaddend.
said first member includes electronic means for .[.transmitting an
electrical signal.]. .Iadd.generating an electromagnetic
transmission to activate electrical conduction in said second
member.Iaddend.; and
said second member includes electronic means .[.for receiving the
electrical signal.]. .Iadd., responsive to said electromagnetic
transmission, for conducting an electrical signal.Iaddend.. 6. An
apparatus as defined in claim 5, wherein said magnet means includes
a
rare-earth element. 7. .[.An apparatus as defined in claim 1,
wherein:.]. .Iadd.A transcutaneous coupling apparatus,
comprising:
a first member positioned subcutaneously;
a second member positioned supercutaneously; and
magnet means for magnetically securing said second member to said
first member; and wherein .Iaddend.
said transcutaneous coupling apparatus is a bio-electronic signal
coupling device;
said first member includes:
a first electrically conductive coil having two ends, each of said
two ends being embedded in subcutaneous tissue; and
said second member includes:
a second electrically conductive coil; and
signal generating means, electrically connected to said second
coil, for providing an electrical signal to said second coil so
that said signal is electromagnetically transferred
transcutaneously to said first coil for
electrically stimulating the subcutaneous tissue. 8. An apparatus
as defined in claim 7, wherein said magnet means includes a
rare-earth
element. 9. An apparatus as defined in claim 7, wherein said magnet
means includes:
a first rare-earth magnet associated with said first coil; and
a second rare-earth magnet, associated with said second coil, for
magnetically coupling with said first rare-earth magnet so that
said first and second coils are positioned to achieve
electromagnetically inductive
coupling. 10. An apparatus as defined in claim 9, wherein said
magnet means further includes:
a third rear-earth magnet associated with said first coil; and
a fourth rare-earth magnet, associated with said second coil, for
magnetically coupling with said third rare-earth magnet, said third
and fourth magnets having as their attractive polarities magnetic
poles of opposite polarities to the attractive polarities of said
first and second
magnets, respectively. 11. A hearing .[.air.]. .Iadd.aid.Iaddend.,
comprising:
sound detector means for detecting sound and converting it into an
electrical signal;
transmitter means, positioned on the ouside of the skin of a user
of said hearing aid, for transmitting the electrical signal;
receiver means, positioned beneath the skin of the user, for
receiving the transmitted electrical signal .Iadd.and for
conducting said signal into tissue beneath the skin of the
user.Iaddend.; and
magnet means for coupling said transmitter means with said receiver
means.Iadd., .Iaddend..[.so that.]. .Iadd.with .Iaddend.said
transmitter means and said receiver means .[.are.]. on opposite
sides of the surface of the skin of the user.Iadd., so that
electrical conduction is activated in said receiver means and from
said receiver means into tissue beneath the skin of the user in
response to said transmitter means transmitting
the electrical signal.Iaddend.. 12. A hearing aid as defined in
claim 11,
wherein said magnet means includes a rare-earth element. 13. .[.A
hearing aid as defined in claim 12, wherein:.]. .Iadd.A hearing
aid, comprising:
sound detector means for detecting sound and converting it into an
electrical signal;
transmitter means, positioned on the outside of the skin of a user
of said hearing aid, for transmitting the electrical signal;
receiver means, positioned beneath the skin of the user, for
receiving the transmitted electrical signal;
magnet means for coupling said transmitter means with said receiver
means so that said transmitter means and said receiver means are on
opposite sides of the surface of the skin of the user; and
wherein:
said magnet means includes a rare-earth element; .Iaddend.
said receiver means includes a first electrically conductive
coil;
said transmitter means includes a second electrically conductive
coil, said first and second coils being electromagnetically
associated by said magnet means so that said first coil is
responsive to the transmitted electrical
signal. 14. A hearing aid as defined in claim 13, wherein said
first coil
includes an end embedded in a cochlea of the user. 15. A hearing
aid as defined in claim 14, wherein said sound detector means
includes:
transducer means for receiving a sound and converting it to a
proportional electrical signal;
amplifier means for amplifying the proportional electrical
signal;
carrier generator means for generating a carrier electrical signal;
and
amplitude modulation means, responsive to said amplifier means, for
modulating the amplitude of the carrier electrical signal and for
transferring the modulated carrier electrical signal to said second
coil.
6. A hearing aid as defined in claim 15, wherein:
said receiver means further includes a first support member having
said first coil associated therewith;
said transmitter means further includes a second support member
having said second coil associated therewith; and
said magnet means includes:
a first rare-earth magnet associated with said first support member
so that a first polarity of said first magnet is positioned closer
to said transmitter means than is a second polarity thereof;
and
a second rare-earth magnet associated with said second support
member so that a polarity thereof attractive to the first polarity
of said first rare-earth magnet is positioned closer to said first
magnet than is a
non-attractive polarity thereof. 17. A hearing aid as defined in
claim 11, wherein said magnet means includes a plurality of
rare-earth magnets, each of said magnets being associated with a
respective one of said transmitter means and said receiver means
and being grouped in attractive magnetic relation with another one
of said magnets associated with the other of said transmitter means
and said receiver means so that said transmitter means and said
receiver means are magnetically coupled in a predetermined
alignment. 18. A hearing aid, comprising:
sound detector means for detecting sound and for converting it into
an electrical signal;
a first electrically conductive coil having a first end embedded in
the body tissue of a user of said hearing aid and having a second
end embedded in a cochlea of the user;
a second electrically conductive coil connected to said sound
detector means and positioned outside the skin of the user;
a first rare-earth magnet associated with said first coil; and
a second rare-earth magnet, associated with said second coil, for
magnetically coupling with said first rare-earth magnet so that
said first and second coils are positioned to achieve
electromagnetically inductive
coupling. 19. A hearing aid as defined in claim 18, further
comprising:
a third rare-earth magnet associated with said first coil; and
a fourth rare-earth magnet, associated with said second coil, for
magnetically coupling with said third rare-earth magnet, said third
and fourth magnets having as their attractive polarities magnetic
poles of opposite polarities to the attractive polarities of said
first and second
magnets, respectively. 20. A method of .[.transcutaneously.].
coupling .[.an.]. .Iadd.a transcutaneous .Iaddend.apparatus having
an implantable .Iadd.electrical .Iaddend.member and an external
.Iadd.electrical .Iaddend.member, comprising the steps of:
associating a first rare-earth magnet with the implantable
.Iadd.electrical .Iaddend.member;
associating a second rare-earth magnet with the external
.Iadd.electrical .Iaddend.member;
subcutaneously implanting the implantable .Iadd.electrical
.Iaddend.member with the associated first rare-earth magnet;
and
supercutaneously positioning the external .Iadd.electrical
.Iaddend.member and associated second rare-earth magnet .[.so
that.]. .Iadd.for magnetically securing .Iaddend.the second
rare-earth magnet .[.is magnetically secured.]. with the first
rare-earth magnet .Iadd.so that electrical conduction occurs within
the implantable electrical member and electrical stimulation of
subcutaneous tissue results therefrom in response to
electromagnetic transmission from the external electrical
member to the implantable electrical member.Iaddend.. 21. A method
as defined in claim 20, further comprising the steps of:
associating, prior to the step of subcutaneously implanting the
implantable .Iadd.electrical .Iaddend.member, a third rare-earth
magnet with the implantable .Iadd.electrical .Iaddend.member in
opposing magnetic polarity relation with the first rare-earth
magnet; and
associating a fourth rare-earth magnet with the external
.Iadd.electrical .Iaddend.member in opposing magnetic polarity
relation with the second rare-earth magnet so that the fourth
rare-earth magnet is magnetically secured with the third rare-earth
magnet during the step of supercutaneously positioning the external
.Iadd.electrical .Iaddend.member and so that the external
.Iadd.electrical .Iaddend.member and the implanted .Iadd.electrical
.Iaddend.member are coupled in a predetermined relation.
Description
BACKGROUND OF THE INVENTION
This invention relates generally to apparatus for coupling a member
implanted in a body with a member located outside the body. More
particularly, but not by way of limitation, the invention relates
to a bio-electronic signal coupling device (such as a hearing aid
having a cochlear implant unit and a sound receiving unit)
utilizing rare-earth magnets to properly align and secure an
external member (such as the sound receiving unit) with an internal
member (such as the cochlear implant unit).
In the medical implantable electronic prosthesis field it is
necessary to maintain proper alignment between units implanted
within the body and units associated therewith but located
externally of the body. Specifically, in medical prostheses
involving electrical signal transfers, such as hearing aids, it is
critical to maintain a proper alignment between the implanted and
external units to insure effective signal transfer.
For example, a hearing aid known as an auditory neural prosthesis
is used to electrically stimulate a user's auditory nerve directly
or within the cochlea thereby to enable recognition of
environmental sounds and to improve lip-reading skills. Such a
prosthesis includes an internal, subcutaneously located signal
receiving unit implanted in the user so that an electrical signal
can be conducted to a cochlea of the user. The prosthesis also
includes an external sound detecting and transmitting unit located
outside the skin of the user.
For the sound detecting and transmitting unit to effectively
transmit to the receiving unit electrical signals corresponding to
the detected sounds, the sound detecting and transmitting unit must
be maintained in proper alignment with the receiving unit.
Presently proposed or used devices attempt to maintain alignment by
utilizing eyeglass frames specially constructed to carry the sound
detecting and transmitting unit. This frame structure has the
shortcoming of permitting misalignment between the external and
internal units because the eyeglass frames can slip and otherwise
become easily moved. Such misalignment decreases, if not totally
eliminates, the amplitude of the coupled signal received by the
receiving unit. This decrease or loss of signal results in
decreased or lost cochlea stimulation which causes frustration in
the user of the apparatus because he or she has to continually
readjust the eyeglass frames to maintain the apparatus operative.
This misalignment also hampers the training, evaluation and use of
the prosthesis user.
If the eyeglass frame structure were used with multichannel
auditory neural prostheses which are being developed to provide
frequency coding of detected sounds, the reliability of such
multi-channel devices would be greatly decreased because accurate
alignment is critical to insure that each of the plurality of
signals transmitted by the transmitter means in the multi-channel
transmitter unit is received by the proper receiver means in the
implanted multi-channel receiving unit.
Although proper alignment must be maintained in medical apparatus
having units located both beneath the surface of the skin and above
the skin, it is desirable that there be no mechanical connection
which extends through the skin of the user between the internal and
external units. Although no mechanical connection, which could
rigidly maintain a predetermined distance between the internal and
external units so that no compression of the intervening skin
occurred, is wanted, neither is there desired a coupling device
which adversely affects, such as by compression, the skin extending
between the implanted unit and the external unit. Therefore, what
is desired is an apparatus which secures the external unit with the
internal unit without adversely affecting the intervening
tissue.
Although there have been proposed and made medical apparatus having
implantable units and external units which need to be coupled or
held in alignment by some means, such as the aforementioned type of
hearing aid using an eyeglass frame, we do not know of any such
apparatus which discloses or suggests our invention as disclosed
and claimed hereinbelow.
SUMMARY OF THE INVENTION
The present invention overcomes the above-noted and other
shortcomings of the prior art by providing a novel and improved
medical apparatus coupling device. This apparatus maintains in
proper alignment or desired positional securement a unit which is
disposed beneath the surface of the skin of a user and a unit
located outside the surface of the user's skin. Furthermore, there
is no mechanical connection extending through the user's skin to
maintain this alignment. Additionally, this present invention has
no known significantly adverse effect on the user's skin extending
between the internally located unit and the externally positioned
unit.
Broadly, the present invention provides a transcutaneous coupling
apparatus comprising a first member positioned subcutaneously, a
second member positioned supercutaneously (i.e., outside the skin),
and magnet means for magnetically securing the second member to the
first member.
The first member includes in preferred embodiments electronic means
which can receive an electrical signal or transmit an electrical
signal or perform both functions. Likewise, the second member
includes in a first embodiment means for transmitting the
electrical signal to the receiving first member or in another
embodiment includes electronic means for receiving the electronic
signal transmitted by the first member. Alternatively, the second
member can include means for performing both receiving and
transmitting functions.
When the first and second members specifically include receiving
and transmitting means, respectively, the transcutaneous coupling
apparatus is a bio-electronic signal coupling device for
maintaining a desired positional relationship between the first and
second members so that the proper transmitting and receiving
between the members can occur. In such an embodiment the first
member specifically includes a first electrically conductive coil
having two ends, each of which is embedded in tissue of the user of
the apparatus. The second member in such an embodiment includes a
second electrically conductive coil and signal generating means,
electrically connected to the second coil, for providing an
electrical signal to the second coil so that the signal is
transferred by electromagnetic induction transcutaneously to the
first coil for electrically stimulating the tissue in which the
ends of the first coil are embedded.
The magnet means generally includes a rare-earth element. More
particularly, the magnet means includes a first rare-earth magnet
associated with the first coil of an embodiment of the first
member, and the magnet means also includes a second rare-earth
magnet associated with the second coil of an embodiment of the
second member, for magnetically coupling with the first rare-earth
magnet so that the first and second coils are positioned to achieve
electromagnetically inductive coupling. To maintain the first and
second members in a predetermined relation, the magnet means
further includes a third rare-earth magnet associated with the
first coil and a fourth rare-earth magnet, associated with the
second coil, for magnetically coupling with the third rare-earth
magnet. To achieve the predetermined alignment, the third and
fourth magnets have as their attractive polarities magnetic poles
of opposite polarities to the attractive polarities of the first
and second magnets so that each of the magnets on the first member
will be attracted to only one of the magnets located on the second
member.
From the foregoing it is a general object of the present invention
to provide a novel and improved medical apparatus coupling device.
Other and further objects, features and advantages of the present
invention will be readily apparent to those skilled in the art when
the following description of the preferred embodiments is read in
conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic illustration and block diagram of a preferred
embodiment of the present invention.
FIG. 2 is a sectional side elevational view of a coil assembly of
the preferred embodiment of the present invention.
FIG. 3 is an end elevational view of the coil assembly shown in
FIG. 2.
FIG. 4 is a schematic and block diagram of the electronic elements
of the preferred embodiment of the present invention.
FIG. 5 is a sectional side elevational view of a coil assembly of a
second preferred embodiment of the present invention.
.Iadd.FIG. 6 is a block diagram of another preferred embodiment of
the present invention. .Iaddend.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION
The medical apparatus coupling device of the present invention
provides transcutaneous coupling of a subcutaneously located first
member with a supercutaneously (i.e., outside the skin) positioned
second member. To describe this invention, specific reference will
be made to preferred embodiments of a bio-electronic signal
coupling device which assists the hearing of a user of the device.
The signal coupling device is particularly a hearing aid 2
schematically illustrated by the block diagram shown in FIG. 1.
The hearing aid 2 includes an internal first member 4 which is
designated in FIG. 1 as an internal coil assembly 6. In the
preferred embodiment the internal coil assembly 6 is a cochlear
implant unit containing electronic receiver means for receiving a
transmitted signal. However, it is to be noted that in other
embodiments the internal coil assembly 6 can include means for
transmitting a signal or means for both receiving and transmitting
signals. .Iadd.See, for example, transmitter 48 depicted in FIG. 6.
.Iaddend.Units other than signal receiving or transmitting ones can
also comprise the first member.
The internal coil assembly 6 is subcutaneously located beneath a
layer of tissue 8 which includes the epidermal and dermal layers of
the skin of the user of the device when the device is the preferred
embodiment hearing aid 2. FIGS. 2 and 4 disclose that the internal
coil assembly 6 includes a first electrically conductive coil 10 of
wire having two ends embedded in subcutaneous tissue. Specifically,
as shown in FIG. 4 a first end or electrode 12 of the coil 10 is
inserted in a cochlea of the user and a second end or electrode 14
is inserted in adjacent tissue as a reference electrode. In the
preferred embodiment the first coil 10 comprises six hundred turns
of 40 AWG copper wire. This wire is wound on a first support member
16 comprising a delrin bobbin 18 placed in a ceramic, pot-type
core-half 20. The core-half 20 preferably has a right circular
cylindrical shape because a hole having a complementary shape can
be readily cut with a circular trephine into the bone in which the
internal core assembly 6 is to be inserted.
In addition to the first member 4, the present invention includes a
second member 22 which in the preferred embodiment includes signal
generating and transmitting means 24 located supercutaneously of
the user of the invention. FIG. 1 reveals the means 24 includes a
sound detector and signal conditioner means 26 and an external coil
assembly 28. .Iadd.In the preferred embodiment depicted in FIG. 6,
the second member includes a receiver 50. .Iaddend.
The external coil assembly 28 includes a second electrically
conductive coil 29. In the preferred embodiment the second coil 29
includes four hundred turns of 38 AWG copper wire wound on a second
support member comprising a delrin bobbin and a ceramic, pot-type
core-half similar to the bobbin 18 and core-half 20 shown in FIG. 2
constituting the internal coil assembly 6.
The sound detector and signal conditioner 26 is electrically
connected to the second electrically conductive coil 29 and
generates an electrical signal which is electromagnetically
transferred transcutaneously by the second coil 29 to the first
coil 10 for electrically stimulating the subcutaneous tissue
(specifically, the cochlea) in which the electrodes 12 and 14 of
the first coil 10 are embedded. FIG. 4 shows the sound detector and
signal conditioner means 26 includes a transducer, specifically a
microphone 30, for detecting a sound and converting it into a
proportional electrical signal. The proportional electrical signal
is amplified by amplifier means 32 and input into amplitude
modulation circuit means 34. The amplitude modulation circuit means
34 utilizes the amplified electrical signal to modulate a carrier
signal which is generated by carrier frequency generator means 36.
In the preferred embodiment the carrier frequency generator means
36 provides a 16 kHz carrier signal which is amplitude modulated by
the electrical signal coming from the amplifier means 32. The
resultant amplitude modulated signal is provided to the second coil
29 for electromagnetic transmission transcutaneously through the
intervening tissue 8 to the first coil 10. The microphone 30,
amplifier means 32, amplitude modulation circuit means 34 and
carrier frequency generator means 36 depicted in FIG. 4 are of the
type as are known in the art.
For the electromagnetically inductive transmission between the
first coil 10 and the second coil 29 to be properly achieved, it is
necessary to provide means for properly securing the external coil
assembly 28 (and the sound detector and signal conditioner means 26
if it is unistructurally combined with the external coil assembly
28) with the internal assembly 6 without significantly adversely
affecting the intervening tissue 8. This is achieved in the present
invention with magnet means for magnetically securing the second
member 22 with the first member 4. The magnet means
electromagnetically associates the receiver means provided by the
preferred embodiment internal coil assembly 6 with the transmitter
means provided by the preferred embodiment means 24 so that the
first coil 10 of the receiver means is responsive to the
transmitted electrical signal transmitted by the second coil 29 of
the preferred embodiment transmitter means. .Iadd.For the FIG. 6
embodiment, the magnet means, comprising two magnets 52, 54,
magnetically secures the transmitter 48 and the receiver 50.
.Iaddend.
In the preferred embodiment receiver means or internal coil
assembly 6 shown in FIG. 2 the magnet means include a rare-earth
element which is particularly a first rare-earth magnet 38
associated with the first coil 10 by being concentrically
positioned therewith in the pot-type core-half 20. The rare-earth
element included within the magnet means may be any appropriate one
of the group of chemical elements including atomic numbers between
58 and 71. In the preferred embodiment the rare-earth element is
samarium which is combined with cobalt to provide a samarium-cobalt
magnet (e.g., SmCo.sub.5) having a long magnetic stability and a
large maximum energy product.
In addition to the first rare-earth magnet 38 forming a part of the
magnet means of the present invention, there is a second rare-earth
magnet associated with the second coil 29 of the second member 22
for magnetically coupling with the first rare-earth magnet 38 so
that the first and second coils 10 and 29 are positioned for
electromagnetically inductive coupling. The magnetic coupling
arises by placing attractive poles of the first and second magnets
toward each other so that the magnetic lines of force extend
through the intervening tissue 8 to retain the internal and
external coil assemblies in alignment adjacent the intervening
skin. For example, the magnetic north pole of the first rare-earth
magnet 38 can be positioned within the first member 4
(specifically, within the core-half 20) so that it lies closer to
the second member 22 (specifically, the core-half of the external
coil assembly 28) than does the magnetic south pole of the first
magnet 38. This positioning of the first magnet 38 requires that
the magnetic south pole of the second rare-earth magnet be
positioned in the second member 22 so that it will magnetically
couple with the magnetic north pole of the first magnet when the
second member 22 is placed to properly position the second coil 29
relative to the first coil 10.
To use the preferred embodiment of the present invention depicted
in FIGS. 1-4, the first member 4 containing the first rare-earth
magnet 38 is subcutaneously implanted in the user of the apparatus.
During implantation the electrodes 12 and 14 of the first coil 10
are implanted in the respective locations previously described.
Next, the second member 22, having the second rare-earth magnet
associated therewith, is positioned supercutaneously adjacent the
outer surface of the user's skin so that the first and second
magnets magnetically secure themselves together thereby properly
positioning the first and second coils 10 and 29 for maximum signal
transference from the second member 22 to the first member 4.
The signal which is to be transferred from the second member 22 to
the first member 4 is obtained by using the transducer or
microphone 30 to detect an ambient sound and converting it into a
proportional electrical signal, amplifying this signal, and
amplitude modulating with this amplified signal the 16 kHz carrier
signal generated by the carrier frequency generator means 36. The
amplitude modulated signal is transferred to the second coil 29 of
the second member 22 for electromagnetically inductive coupling
with the first coil 10 of the first member 4. The
electromagnetically induced signal received by the first coil 10 is
impressed across the reference tissue and cochlea tissue to which
the electrodes of the first coil are embedded. This electrical
stimulation of the cochlea enhances the hearing and lip-reading
skills of the user.
The previously described type of system utilizing the single first
coil 10 and the single second coil 29 is known as a single-channel
hearing aid because only a single signal is transferred to the user
of the apparatus at any one time. However, there are multi-channel
devices which are being developed for simultaneously transferring a
plurality of signals to permit frequency coding and subsequent
frequency analysis of the detected sounds. To insure the proper
operation of such multi-channel devices, it is necessary to
accurately align the respective transmitting and receiving channels
comprising, for example, a plurality of coils similar to those
shown in the drawings. The initial alignment and subsequent
maintenance of the alignment would be difficult using the preferred
embodiment shown in FIGS. 1--4 because with only a single pair of
magnets, the first member and second members could rotate whereby
respective channels could become misaligned. To prevent
misalignment, a plurality of magnets forming a multiple number of
magnet pairs can be used as shown in a second preferred embodiment
illustrated in FIG. 5. It is to be noted that although the FIG. 5
embodiment is of the single-channel type, it could readily be
adapted to a multi-channel type.
The FIG. 5 embodiment discloses a support member 40 and coil
assembly 42 similar to that shown in FIGS. 2 and 3. However, the
magnet means of the FIG. 5 embodiment is different from that shown
in FIG. 2 because two rare-earth magnets are disposed in the
support member 40 of FIG. 5. A first rare-earth magnet 44 is
magnetically coupled with a second rare-earth magnet (not shown)
which is properly situated in a second member which is similar to
the second member 22. A third rare-earth magnet 46 shown in FIG. 5
is paired with a fourth rare-earth magnet (not shown) which is
properly situated in the second member of the second preferred
embodiment. Therefore, the magnets are grouped in attractive
magnetic relation between the receiver and transmitter means of the
first and second members, respectively.
It is apparent that through the use of the plurality of magnets
depicted in FIG. 5, misalignment is less likely to occur once the
first and second members are magnetically coupled. However, it is
sometimes necessary to orient the first member with respect to the
second member in a single, predetermined alignment.
If the two magnets of the first member shown in FIG. 5 has the same
polarity orientation and the two magnets of the second member had
the same polarity orientation as between themselves but opposite
that of the magnets of the first member, the second member could be
magnetically coupled to the first member in either of two
directions. For example, if each of the magnets 44 and 46 shown in
FIG. 5 has its magnetic north pole facing the second member and
each of the magnets in the second member had its magnetic south
pole facing the first member, the first and second members could be
positively related so that either the first and second magnets and
the third and fourth magnets were magnetically coupled or the first
and fourth magnets and the second and third magnets were
magnetically coupled.
To restrict the alignment between the first and second members to a
single predetermined position, the first and third rare-earth
magnets 44 and 46 can be disposed in the first member so that the
two polarities facing the second member are opposite. For example,
the first magnet could have its magnetic north pole disposed for
coupling with the second member and the third magnet could have its
magnetic south pole disposed for coupling with the second member.
To complement this pole placement, the second magnet could be
disposed in the second member so that its magnetic south pole is
disposed for coupling with the first member and the third magnet
could be disposed in the second member so that its magnetic north
pole is disposed for coupling with the first member. With such
magnetic polarities positioned for coupling the first and second
members, the first and second members can only be magnetically
coupled in a single alignment because coupling will occur only when
the first magnet and second magnet are aligned and the third magnet
and fourth magnet are aligned. The reverse alignment of the magnets
of the first and second members results in similar poles facing
each other thereby causing a repulsive force. This can be more
generally stated by saying that the third and fourth magnets have
as their attractive polarities magnetic poles of opposite
polarities to the attractive polarities of the first and second
magnets, respectively.
Although the specific embodiments described above disclose either a
single pair of magnetic slugs in the shape of small disks located
in the centers of symmetrical pot-type core halves or two such
pairs of magnetic slugs, it is to be noted that other
configurations are also feasible. For example, a ring magnet
disposed along the periphery of the pot-type core-half could be
used. Likewise, three disk-shaped magnets could be spaced at
120.degree. intervals around each of the first and second members.
Still further, a single magnet could be disposed in either the
internal member or the external member and a magnetically
attractive material, such as a ferromagnetic material, could be
placed in the other member so that the attractive material is held
in alignment by the single magnet. Other forms of magnet means can
likewise be used and yet remain within the scope of the present
invention.
It is also to be noted that although the preferred embodiment of
the present invention was described with reference to a
bio-electronic signal coupling device (more particularly, a hearing
aid), the present invention contemplates any medical apparatus
having a first member implanted below the surface of the skin of
the user and having a second member located externally to the
user's skin but transcutaneously coupled to the first member.
Still further, it is to be noted that the term "hearing aid" as
used herein is not limited to those devices which amplify sounds,
but rather is intended to encompass all suitable devices which
assist one in hearing and/or comprehending sound.
Thus, the present invention of a medical apparatus coupling device
is well adapted to carry out the objects and attain the ends and
advantages mentioned above as well as those inherent therein. While
preferred embodiments of the invention have been described for the
purpose of this disclosure, numerous changes in the construction
and arrangement of parts can be made by those skilled in the art,
which changes are encompassed within the spirit of this invention
as defined by the appended claims.
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