U.S. patent application number 11/389554 was filed with the patent office on 2007-01-18 for magnetic navigation system.
This patent application is currently assigned to Sterotaxis, Inc.. Invention is credited to Seth Burgett, Francis M. IV Creighton.
Application Number | 20070016010 11/389554 |
Document ID | / |
Family ID | 46298934 |
Filed Date | 2007-01-18 |
United States Patent
Application |
20070016010 |
Kind Code |
A1 |
Creighton; Francis M. IV ;
et al. |
January 18, 2007 |
Magnetic navigation system
Abstract
A system for magnetically navigating a medical device in an
operating region within the body of a patient. The system includes
a magnet having a front field projecting from the front of the
magnet sufficient to project a magnetic field into the operating
region in the patient. The magnet is mounted for movement between a
navigation position in which the magnet is located adjacent to the
patient with the front of the magnetic generally facing the
operating region, and an imaging position in which the magnet is
spaced from the patient and the front generally faces away from the
operating region.
Inventors: |
Creighton; Francis M. IV;
(St. Louis, MO) ; Burgett; Seth; (Glen Carbon,
IL) |
Correspondence
Address: |
Bryan K. Wheelock
Suite 400
7700 Bonhomme
St. Louis
MO
63105
US
|
Assignee: |
Sterotaxis, Inc.
|
Family ID: |
46298934 |
Appl. No.: |
11/389554 |
Filed: |
March 24, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10347525 |
Jan 17, 2003 |
7019610 |
|
|
11389554 |
Mar 24, 2006 |
|
|
|
10056227 |
Jan 23, 2002 |
6975197 |
|
|
10347525 |
Jan 17, 2003 |
|
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Current U.S.
Class: |
600/424 |
Current CPC
Class: |
A61B 6/12 20130101; A61B
34/73 20160201; A61B 2034/732 20160201; H01F 7/0278 20130101; A61B
2034/733 20160201; A61B 34/70 20160201 |
Class at
Publication: |
600/424 |
International
Class: |
A61B 5/05 20060101
A61B005/05 |
Claims
1. A system for magnetically navigating a medical device in an
operating region within the body of a patient, the system includes
a magnet having a front field projecting from the front of the
magnet sufficient to project a magnetic field into the operating
region in the patient, the magnet is mounted for movement between a
navigation position in which the magnet is located adjacent to the
patient with the front of the magnetic generally facing the
operating region, and an imaging position in which the magnet is
spaced from the patient and the front generally faces away from the
operating region.
2. A magnet system for applying a magnetic field of selected
direction to an operating region inside a patient on a support, to
control a magnetic medical object in the operating region, the
magnet system comprising: a base, a magnet mounted on the base, the
base being movable with respect to the support, to move the magnet
from an active position in which the magnet is adjacent the
patient, and an inactive position, in which the magnet is spaced
from the patient.
3. A magnet applicator for applying a magnetic field of selected
direction to an operating region within the body of a patient, the
magnet applicator comprising a magnet; a support for mounting the
magnet and changing the position and orientation of the magnet to
change the direction of magnetic field applied to the operating
region, the support capable of pivoting the magnet about a first
axis that rotates about a second axis perpendicular to the first
axis, and translating the magnet in two mutually perpendicular
horizontal directions.
4. A magnet applicator for applying a magnetic field of selected
direction to an operating region within the body of a patient, the
magnet applicator comprising a base, a magnet having a front face
and a plurality of other faces, a support on the base for mounting
the magnet and changing the position and orientation of the magnet
to change the direction of magnetic field applied to the operating
region, the base being movable between an active position in which
the magnet is oriented with the front face facing the patient, and
an inactive position in which that magnet is oriented with the
front face is not facing the patient.
5. A magnet applicator for applying a magnetic field of selected
direction to an operating region within the body of a patient, the
magnet applicator comprising a magnet; a support for mounting the
magnet and changing the position and orientation of the magnet to
change the direction of magnetic field applied to the operating
region, the support mounting the magnet to pivot about a first
axis, which is rotatable about a second axis perpendicular to the
first axis; and translating the magnet in two mutually
perpendicular horizontal directions.
6. The magnet applicator according to claim 5 wherein the second
axis is parallel to one of the mutually perpendicular horizontal
directions.
7. (canceled)
8. (canceled)
9. (canceled)
10. A magnet system for applying a magnetic field of selected
direction to an operating region inside a patient on a support, to
control a magnetic medical object in the operating region, the
magnet system comprising: first and second magnets mounted on
opposite sides of the operating region, each of the magnets being
movable relative to the operating region from an activ position in
which the magnets apply a magnetic field to the operating region
and an inactive position in which the magnets apply a magnetic
field to the operating region.
11. The magnet system according to claim 10 further comprising a
pivotally mounted base, the pivoting of the base changing the
position and/or orientation of the magnet relative to the operating
region.
12. The magnet system according to claim 10 wherein the magnets
have a front face and at least one side face from which the
magnetic field projected by the magnet is substantially less than
the magnet field projected from the front face, in the active
position the magnet being oriented with the front face base
generally toward the operating region, and in the inactive position
the magnet being oriented with the at least one side face oriented
toward the operating region.
13. A magnet system for applying a magnetic field of selected
direction to an operating region inside a patient on a support, to
control a magnetic medical object in the operating region, the
magnet system comprising: first and second magnets mounted on
opposite sides of the operating region, each of the magnets being
movable relative to the operating region from an active position in
which the magnets apply a magnetic field sufficient to control a
magnet element in the device but which interferes with the imaging
of the operating region; and second position in which the magnets
do not apply a magnetic field that interferes with the imaging of
the operating region.
14. A magnet system for navigating a magnetic medical device in the
operating region in a patient, the system comprising at least one
magnet for applying a magnet field to the operating region in the
patient, the magnet being mounted for movement between an active
position in which the magnet is adjacent the patient to apply a
magnetic field to the operating region, and an inactive position in
which the magnet is spaced sufficiently from the operating region
that it does not interfere with the x-ray imaging of the operating
region.
15. A magnet system for navigating a magnetic medical device in the
operating region in a patient, the system comprising at least one
magnet for applying a magnet field to the operating region in the
patient, the magnet being mounted for movement between an active
position in which the magnet is adjacent the patient to apply a
magnetic field to the operating region, and an inactive position in
which the magnet is spaced sufficiently from the operating region
that it do s not apply a magnetic field of greater than 5 gauss to
imaging equipment positioned to image the operating region.
16. The system according to claim 15 interfere with the x-ray
imaging of the operating region.
17. A magnet system for applying a magnetic field to an operating
region in a patient, the system comprising at least one magnet
mounted to move between an active position in which the magnet is
adjacent the patient to project a controllable magnetic field into
the operating region and an inactive position in which the magnetic
field projected by the magnet into the operating region is less
than about 5 gauss.
18. The magnet system according to claim 17 wherein there are two
magnets one on each side of the patient, and wherein the total
magnetic field applied by the magnets in the inactive position is
less than about 5 gauss.
19. A magnet system for applying a magnetic field to an operating
region in a patient, the system comprising at least one magnet
mounted to move between an active position in which the magnet is
adjacent the patient to project a controllable magnetic field into
the operating region and an inactive position in which the field
projected by the magnet in the operating region does not interfere
with imaging of the operating region.
20. The magnet system according to claim 19 wherein there are two
magnets one on each side of the patient, and wherein the total
magnetic field applied by the magnets in the inactive position is
less than about 5 gauss.
21. The magnet system according to claim 19 wherein the magnet is
mounted on a pivoting base, and wherein the magnet moves between
the active and inactive positions by the pivoting of the base.
22. The magnet system according to claim 19 wherein the magnet both
pivots and translates relative to the operating region as the base
pivots.
23. The magnet system according to claim 19 wherein the base pivots
about a pivotally mounding further has a roller that rolls on an
accurate track as the base pivots.
24. The magnet system according to claim 19 wherein a first face of
the magnet faces the operating region when the magnet is in the
active position, and a second face of the magnet faces the
operating region in the inactive position.
25. The magnet system according to claim 19 wherein the magnet has
a preferred direction in which the magnet projects a relatively
strong magnetic field and at least one non-preferred direction in
which the magnet projects a relatively weak magnetic field, the
preferred direction generally facing the operating region when the
magnet is in its active position, and the a non-preferred direction
generally facing the operating region when the magnet is in its
inactive position.
26. A magnetic navigation system comprising: a support; a magnet
assembly on either side of the support for applying a controllable
magnetic field to an operating region in a patient on the support;
the magnet assembly comprising a magnet, and a support that moves
the magnet to change the direction of the field applied by the
magnet to the operating region, the support selectively pivoting
the magnet about a first axis, rotating the magnet about a second
axis perpendicular to the first axis, and translating the magnet in
a first and second mutually perpendicular directions.
37. The magnet assembly according to claim 36 wherein each magnet
assembly further comprises a base for mounting the support, each
base being movable to move the magnet from an operative position
adjacent the patient support to an inoperative position.
38. The magnet assembly according to claim 36 wherein the base
pivots translating and/or rotating the magnet relative to the
operating region.
39. The magnet assembly according to claim 36 wherein the second
axis and one of the first and second directions are generally
parallel.
40. The magnet assembly according to claim 36 wherein the second
axis and one of the first and second directions extend in a
direction toward the patient.
41. The magnet assembly according to claim 36 wherein the second
axis is in a direction generally toward the patient.
42. The magnet assembly according to claim 36 in which the second
axis is generally horizontal, oriented generally toward the
patient, and wherein the first and second directions are in a
generally horizontal plane, with the first direction extending
generally toward the patient, and the second direction extending
generally perpendicular thereto.
43. A magnetic navigation system for applying a magnetic field in a
selected direction to control a medical object in an operating
region in the patient, the system comprising a patient support for
supporting a patient, first and second magnet assemblies on
opposite sides of the patient support, each magnet assembly
comprising at least one magnet for applying a magnetic field to an
operating region between the magnet assemblies in a patient on the
support, and a support for supporting the at least one magnet and
moving the at least one magnet to change the direction of magnetic
field applied by magnet assemblies to the operating region.
44. The magnetic assembly according to claim 43 wherein the
supports pivot the at least one magnet about a first axis that
rotates about a second axis perpendicular to the first.
45. The magnetic assembly according to claim 43 wherein the
supports translate the at least one magnet in first direction
toward and away from the operating region.
46. The magnetic assembly according to claim 43 wherein the support
translates the magnet perpendicular to the first direction.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuation application of U.S. patent
application Ser. No. 10/347,525, filed Jan. 17, 2003, which is a
continuation-in-part of U.S. patent application Ser. No.
10/056,227, filed Jan. 23, 2002, the entire disclosures of which
are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] This system relates to magnetic navigation of medical
devices in the body, and in particular to a system for applying a
magnetic field of selected direction to an operating region in a
subject's body to orient a magnetically responsive medical
device.
[0003] Magnetic navigation of medical devices has significantly
improved to ability of medical professionals to control medical
devices in the body. Early magnetic navigation techniques involved
the use of superconducting magnets. While these techniques were,
and remain, highly effective, advances in permanent magnetic
materials and in the design of permanent magnets, have made it
possible to use permanent magnets for magnetic navigation. While
the magnetic fields created by superconducting magnets can be
readily changing the currents in the superconducting
electromagnetic coils, in order to change the magnetic field
created by permanent magnets for navigation, it is generally
necessary to change the position and/or orientation of the
permanent. In order to accurately control the magnetic field
applied by permanent magnets, it is necessary to accurately control
the position and/or orientation of the permanent magnet.
SUMMARY OF THE INVENTION
[0004] The present invention relates to a magnetic navigation
system, and in particular to a system including magnet units
comprising a permanent magnet, and a support for controlling the
position and orientation of a permanent magnet. The system is
adapted for magnetically navigating a medical device in an
operating region within the body of a patient. Generally, the
system comprises a magnet having a front field projecting from the
front of the magnet sufficient to project a magnetic field into the
operating region in the patient. The magnet is mounted for movement
between a navigation position in which the magnet is located
adjacent to the patient with the front of the magnetic generally
facing the operating region, and an imaging position in which the
magnet is spaced from the patient and the front generally faces
away from the operating region.
[0005] According to another aspect of the invention the system
includes a magnet system comprising: a magnet and a support for
mounting the magnet and changing the position and orientation of
the magnet to change the direction of magnetic field applied to the
operating region. The support is preferably capable of pivoting the
magnet about a first axis that rotates about a second axis
perpendicular to the first axis, and translating the magnet,
preferably parallel to the second axis.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 is a perspective view of a magnetic surgery suite
incorporating magnet assemblies in accordance with the principles
of this invention;
[0007] FIG. 1A is a top plan view of the magnetic surgery
suite;
[0008] FIG. 2 is an exploded front perspective view of one of the
magnet assemblies (the other magnet assembly being a mirror image
thereof), with the cover removed to show details of
construction;
[0009] FIG. 3 is a front perspective view of the magnet assembly,
with the cover removed;
[0010] FIG. 4 is a front perspective view of the magnet assembly,
showing the lower cover;
[0011] FIG. 5 is a front perspective view of the magnet assembly,
showing the upper cover;
[0012] FIG. 6 is a rear perspective view of the magnet
assembly;
[0013] FIG. 7 is a front elevation view of the magnet assembly;
[0014] FIG. 8 is a further exploded front perspective view of the
positioner system of the magnet assembly
[0015] FIG. 9 is a front elevation view of the positioner system of
the magnet assembly;
[0016] FIG. 10 is a left side elevation view of the positioner
system of the magnet assembly
[0017] FIG. 11 is a right side elevation view of the positioner
system of the magnet assembly;
[0018] FIG. 12 is a rear elevation view of the positioner
system;
[0019] FIG. 13 is a top plan view of the positioner system;
[0020] FIG. 14 is a bottom plan view of the positioner system;
[0021] FIG. 15 is a front elevation view of the phi drive mechanism
of the magnet assembly;
[0022] FIG. 16 is a top plan view of the phi drive mechanism;
[0023] FIG. 17 is a left side elevation view of the phi drive
mechanism;
[0024] FIG. 18 is a right side elevation view of the phi drive
mechanism;
[0025] FIG. 19 is a front elevation view of the front plate of the
phi drive mechanism;
[0026] FIG. 20 is a left side elevation view of the front plate of
the phi drive mechanism;
[0027] FIG. 21 is a right side elevation view of the front plate of
the phi drive mechanism;
[0028] FIG. 22 is a horizontal transverse view of the front plate
of the phi drive mechanism, taken along the plane of line 22-22 in
FIG. 19;
[0029] FIG. 23 is an exploded perspective view of the phi drive
mechanism;
[0030] FIG. 24 is a front elevation view of the theta drive
mechanism of the magnet assembly;
[0031] FIG. 25 is a top plan view of the theta drive mechanism;
[0032] FIG. 26 is a left side elevation view of the theta drive
mechanism;
[0033] FIG. 27 is a bottom plan view of the theta drive
mechanism;
[0034] FIG. 28 is a front perspective view of the theta drive
mechanism;
[0035] FIG. 29 is a front elevation view of theta drive motor;
[0036] FIG. 30 is a top plan view of the theta drive motor;
[0037] FIG. 31 is a bottom plan view of the theta drive motor;
[0038] FIG. 32 is a left side elevation view of the theta
motor;
[0039] FIG. 33 is an exploded front perspective view of the theta
motor;
[0040] FIG. 33 is an a top plan view of the z drive mechanism
[0041] FIG. 34 is an front elevation view of the z drive
mechanism;
[0042] FIG. 35 is a left side elevation view of the z drive
mechanism;
[0043] FIG. 36 is a right side elevation view of the z drive
mechanism;
[0044] FIG. 37 is bottom plan elevation of the z drive
mechanism;
[0045] FIG. 38 is an exploded perspective view of the z drive
mechanism
[0046] FIG. 39 is a perspective view of the pedestal;
[0047] FIG. 40 is an exploded front perspective view of the
pedestal showing the pivot assembly, the drive system assembly, and
the locking system;
[0048] FIG. 41 is an exploded front perspective view of the
pedestal with the pivot assembly, the drive system assembly, and
the locking system assembly removed;
[0049] FIG. 42 is a bottom plan view of the pedestal;
[0050] FIG. 43 is a longitudinal cross sectional view of the
pedestal taken along the plane of line 43-43 in FIG. 42;
[0051] FIG. 44 is a side elevation view of the pedestal;
[0052] FIG. 45 is an exploded perspective view of the pivot
assembly for pivotally mounting the pedestal;
[0053] FIG. 46 is a perspective view of the drive mechanism;
[0054] FIG. 47 is a perspective view of the drive assembly.
[0055] FIG. 48 is a side elevation view of the magnet.
[0056] FIG. 49 is a front elevation view of the magnet.
[0057] Corresponding reference numerals indicate corresponding
parts throughout the several views of the drawings.
DETAILED DESCRIPTION OF THE INVENTION
[0058] A magnetic surgery suite incorporating magnet units in
accordance with the principles of this invention is indicated
generally as 20 in FIG. 1. As shown in FIG. 1, the suite 20
comprises an operating room 22 and a control room 24. The control
room 24 is preferably adjacent to the operating room 22, and has a
window 26 from which the procedure taking place in the operating
room 22 can be viewed. However, the control room 24 does not have
to be adjacent to the operating room 22, and instead could be
located remotely from the operating room, for example on a
different floor, or in a different building, or even in a different
city.
[0059] The operating room 22 includes a patient support, such as a
patient bed 26, and a pair of magnet units 28 and 30, disposed on
opposite sides of the patient bed to project a magnetic field into
the operating region in a patient on the patient bed. The operating
room also includes an imaging system 32, comprising a C-arm
mounting at least one x-ray source 34 and at least one x-ray
receiver 36, such as an amorphous silicon imaging plate. Cabinets
38 and 40 are provided for computer controllers and other
electronics for operating the magnet units 28 and 30 and the
imaging system 32. A plurality of displays 42 (six in this
preferred embodiment) are mounted on an articulating arm 44 from
the ceiling. The displays 42 display images from the imaging system
32, and screens from the control system for operating the magnet
units 28 and 30. A plurality of controls 46 are provided on the
patient bed 26 for operating a user interface to control the magnet
units 28 and 30, in conjunction with the screens displayed on the
displays 42.
[0060] The control room 24 includes a cabinet 48 for a processor
for operating the user interface for controlling the magnet units
28 and 30. A plurality of displays 50 (two in this preferred
embodiment) are provided for displaying images from the imaging
system 32, and screens from the user interface. A plurality of
controls 52 are provided on the patient bed 26 for operating a user
interface to control the magnet units 28 and 30, in conjunction
with the screens on the displays 52.
[0061] Each of the magnet units 28 and 30 projects a strong magnet
field from its front face, so that together, the magnets provide a
magnet field of sufficient strength to orient a magnetic medical
device in an operating region in the patient on the patient bed 26.
Because of the strength of the field projected by the magnet units
28 and 30, the units are preferably rotatably mounted to swing
between an operative position in which the units face the patient
support, and project a field into the operating region in the
patient on the patient bed, and a stowed position, in which the
magnet units do not face the patient bed.
[0062] As shown in FIG. 2, each of the magnet units 28 and 30
comprises a magnet 100, a mechanism 200 for moving the magnet to
change the magnetic field applied by the magnet 100 to the
operating region in a patient, and a pedestal 700, for supporting
the mechanism 200 and magnet 100. As described in more detail below
the magnet 100 is preferably a compound magnet designed so that
relatively small translations and/or rotations result in
significant changes in the magnetic field direction projected into
an operating region in the patient. As described in more detail
below, the mechanism 200 is adapted to support and translate and/or
rotate the magnet 100 to change the direction of the field applied
by the magnet to the operating region in the patient. The magnet
100 and the mechanism 300 are preferably designed so that they can
project a magnetic field in any direction in the operating region
in the patient, or at least so that when both magnet units 28 and
30 are positioned on opposite sides of the patient, the combined
effect of the magnets from the units projects a magnetic field in
any direction.
[0063] In this preferred embodiment, the mechanism preferably
provides three movements of the magnet 100: translation of the
magnet toward and away from the patient (referred to herein as
translation in the z-direction), rotation of the magnet about an
axis parallel to the z-direction, referred to herein as rotation in
the .theta.-direction, and pivoting of the magnet about an axis
perpendicular to the .theta.-axis, referred to herein as pivoting
in the .phi. direction. The movements of the magnet 100 in the z
direction, the .theta.-direction, and the .phi. direction permitted
by the mechanism 300 are sufficient to create a magnetic field of
suitable strength for magnetic navigation, in any direction in the
operating region in the patient. Of course, additional or different
translations and or rotations could be provided for the same or
different magnet design. The strength of the field projected by the
magnets is preferably at least 0.05, and more preferably at least
0.09.
[0064] The magnet 100 is preferably comprised of a plurality of
block 102 arranged and mounted on a backing plate 104, for example
with adhesive the magnet 100 further includes a cover 106,
preferably with a smooth, contoured finished surface enclosing the
assembly of blocks 102. Each of the blocks is made of a permeable
magnetic material, and has a size, shape, position and
magnetization direction to optimize field properties (direction and
strength) while accommodating manufacturing. Examples of suitable
magnets are disclosed in magnets such as those disclosed in U.S.
patent application Ser. No. 10/082,715, filed Feb. 25, 2002, U.S.
patent application Ser. No. 10/056,227, filed Jan. 23, 2003, and/or
U.S. patent application Ser. No. 09/546,840, filed Apr. 11, 2000,
the disclosures of all of which are incorporated herein by
reference.
[0065] The magnet 100 and mechanism 300 are mounted on pedestal
800. As indicated above, and described in more detail below, the
pedestal 800 is mounted for pivoting about a post 802, and has
wheels 804 which allow the pedestal to pivot from a stowed
position, in which the magnet 100 generally faces away from the
patient, to an operative position in which the magnet generally
faces the patient.
[0066] The magnet 100 and mechanism 300 are preferably enclosed is
a cover 200 to protect the mechanism from interference, to prevent
persons from being injured or property from being damaged by the
mechanism, to reduce patient anxiety, and to enhance the appearance
of the unit. As shown in FIG. 3, this cover includes a frame 202
slidably mounted around the base of the mechanism 300. As shown in
FIG. 4, the cover also comprises a front base cap 204, which is
generally U-shaped and adapted to be secured on the front and sides
of the pedestal 800, a top base cap 206, which is adapted to be
secured over the top of the pedestal, around the mechanism 300, and
a rear base cap 208, which is adapted to be secured on the back of
the pedestal cap device. As shown in FIG. 5, the cover 200 also
comprises a front panel 210, adapted for mounting on the frame 202
over the front of the magnet 100 and mechanism 300, and left and
right side panels 212 and 214 adapted for mounting on the frame 202
over the sides of the magnet and mechanism. An inverted U-shaped
frame 216 is mounted on the frame 202 over the back of the
mechanism 300. The frame 216 mounts a conduit 218 for enclosing
power and control leads, and a back panel 220 for covering the back
of the mechanism. A cooling fan unit 222 is mounted on the frame
202, inside the panel 220 to circulate air inside the cover through
louvered openings formed in the cover 220.
[0067] As shown in FIG. 8, the mechanism 300 preferably comprises a
.phi. pivot mechanism 302, for pivoting the magnet 100 in the .phi.
direction; a .theta.-rotation mechanism 402, for rotating the
magnet 100 in the .theta.-direction; and a z-drive mechanism 602
for translating the magnet in the z-direction.
[0068] As shown in FIGS. 15-22, the .phi. pivot mechanism 302
comprises a front plate 304, adapted for mounting the magnet 100.
The front plate 304 is pivotally mounted to a back plate 306. The
back plate 306 is adapted to be mounted on the .theta.-rotation
mechanism 402, and has two parallel brackets 308 and 310 projecting
from its front face for mounting the front plate 304. A hub 312 on
the back of the front plate 304 is pivotally mounted between the
brackets 308 and 310, so that the front plate can pivot. In this
preferred embodiment, the front plate 304, and thus the magnet 100
mounted on the front plate can pivot plus and minus 40.degree., for
a total range of motion of 80.degree.. This range of motion is
based upon the properties of the magnet 100, which in this
preferred embodiment provides a 180.degree. change in field
direction over a range of pivoting of 80.degree.. With a different
magnet, the range of pivoting could be made larger or smaller, as
desired.
[0069] As best shown in FIG. 23, a motor brake 314 is mounted on
bracket 308, a motor mounting adapter 316 is mounted over the motor
brake on the bracket 308. A motor 318 is mounted on the mounting
adapter 316, to turn drive shaft 320 having key 322 thereon. A
housing 24 encloses the motor 318. The drive shaft 320 engages the
front plate 304 so that rotation of the drive shaft caused by motor
318 causes the plate to pivot about the .phi. pivot mechanism.
[0070] A +.phi. limit switch 324 is mounted on a block 326 on the
front face of plate 306, and is adapted to engage a stop 328 on the
front plane 304. Similarly, a -.phi. limit switch 330 is mounted on
a block 332 on the front face of plate 308, and is adapted to
engage a stop 334 on the front plate. A theta sensor flag 336,
which is used by the theta position sensor as described below, is
secured on the back plate 306. Phi sensor flags 338 are secured on
the back of front plate 304. A rotary encoder 340 is mounted on an
encoder mounting plate 342, on the bracket 310, and is driven by
the key 322 on the drive shaft 320.
[0071] The .theta. rotation mechanism 402 is shown in FIGS. 24-28.
The .theta. rotation mechanism 402 comprises a carriage 404, which
is preferably made of aluminum or other strong, lightweight,
non-magnetic material. As best shown in FIG. 28, the carriage 404
has a generally cylindrical opening 406 therein in which the outer
race of a bearing 408 is mounted. Front and rear retaining hubs 410
and 412 are secured together, sandwiching the inner race of the
bearing 408 between them. A retaining ring is mounted in the
carriage 404 over the front retaining hub 414. The phi pivot
mechanism 302 is mounted to the front retaining hub 410, for
rotation around about the theta axis.
[0072] A position sensor 416 is mounted in a recess in the front of
the carriage 404, and is triggered by the flag 338 on the phi pivot
mechanism.
[0073] A cam tray 420, mounting a cam 422, is also secured on the
bottom of the carriage 404. A plurality of stops 424 are also
mounted on the bottom of the carriage 404. A pair of C-shaped
brackets 426 are mounted on the bottom of the carriage for engage
and moving the cover as the theta mechanism 402 moves in the z
direction, as described below. A precision gear 428 is mounted on a
bracket 430 on the bottom of the carriage. The precision gear is
used in sensing the position in the z-direction as a back up to the
position sensing built in to the z drive mechanism 602.
[0074] The driver for the .theta. rotation mechanism 402 is
indicated generally as 434 in FIGS. 29-33. The driver 434 comprises
a servo motor 436, a gear box 438, a reducer mounting plate 440,
and a pinion 442. The pinion 440 engages and drives a gear 442
secured to the rear hub 444, causing rotation in the theta
direction.
[0075] As shown in FIGS. 35-38, the z drive mechanism 602 comprises
base plate 604. Mounting plates 606 are provided on the underside
of base plate, on either side, for securing the base plate to the
pedestal 800. Tracks 608 and 610 are mounted on the plate 604. Two
carriages 612 are slidably mounted on each of the tracks 608 and
610, for slidably mounting the carriage 404 of the theta drive
mechanism 402. A servo motor 614 is mounted on the base plate 604
with a bracket 616. A flexible shaft coupling 618, drive screw
bearing 620 connect ball screw shaft 622 to the servo motor 614.
The end of the ball screw shaft 622 is supported in drive screw
bearing 624. A bracket 626 is mounted on the ball screw shaft 622
and is secured to the underside of the carriage 402, to move the
carriage.
[0076] Stops 628 are mounted on the base plate 604 adjacent one
end. Stops 630 are mounted on the base plate 604 adjacent the other
end. Limit switches 632 and 634 are mounted on the plate 604 with
brackets 636 an 638, respectively. A rotary encoder 640 is mounted
on the base plate 604, and has a pinion 642. The pinion 642 engages
the precision gear 428 on the bottom of the carriage 404, and
measures the position of the carriage relative to the base plate
604. Rails 644 are mounted on the sides of the base plate 604 for
slidably mounting the cover 200.
[0077] As shown in FIG. 39, the pedestal 800 comprises a frame 808,
with a platform 810 for mounting the mechanism 402. The pedestal
800 is pivotally mounted for rotation about post 402, which is
secured to the floor of the operating room. A collar 812 secured to
the frame 808 surrounds, and rotates around the post 402. A drive
mechanism 814 is mounted in the frame 808, for driving the pedestal
800 to rotate around the post 402. A lock mechanism 816 is also
mounted in the frame 808, for securing the pedestal against
movement.
[0078] As shown in FIGS. 40 and 45, the post 802 is surrounded by a
weldment 818. A stop tube 820 is mounted over the post 802,
providing stops 822 and 824 for limiting the rotational movement of
the pedestal. Lower outer mounting plate 826 and lower inner
mounting plate 828, and upper outer mounting plate 830 and upper
inner mounting 832 are secured above and below block 834, mounting
spherical bearing 836. Limit switches 838, 840, 842, and 844 are
mounted on the upper mounting ring and are tripped by movement
relative to cam 846 secured on the top of the post 802.
[0079] As shown in FIGS. 40 and 46, the drive mechanism 814
comprises a motor 848 connected to gear box 850. A hand crank 852
on shaft 854 is also connected to gear box 850. Sheaves 856 and 858
and belt 860 connect the gear box 850 to the drives shaft 862,
which in turn drives drive wheel 864. Thus the motor can operate
the drive wheel, or in a situation where power is not available,
hand crank 852 an be used to operate the drive wheel, and pivot the
pedestal around post 802.
[0080] As shown in FIGS. 40 and 47, the lock mechanism 816
comprises an electric motor 870 which turns a gear box 872 to pull
or push rod 874. The pulling or pushing of the rod 874 causes the
lock member 876 to pivot. The lock member 876 has a tab 878, which
pivots into and engages a slot in the floor of the procedure room.
A hand crank 880 on shaft 882 also turns the gear box 872, to
manually pull or push rod 874. An spring biased interlock bar 884,
interferes with the hand crank, and must be manipulated out of the
way in order to manually operate the lock mechanism 816.
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