U.S. patent application number 11/911195 was filed with the patent office on 2008-11-13 for postural stability platform.
Invention is credited to Scott Chan, Leo Cheung, Stephen M Knecht, Patrick Mak.
Application Number | 20080280740 11/911195 |
Document ID | / |
Family ID | 36684150 |
Filed Date | 2008-11-13 |
United States Patent
Application |
20080280740 |
Kind Code |
A1 |
Knecht; Stephen M ; et
al. |
November 13, 2008 |
Postural Stability Platform
Abstract
Postural stability platforms include at least one movement
resistant element Fixed to a base and coupled to a plate. The plate
is movable relative to the base but the movement resistant elements
resist movement of the plate. Accordingly, subjects standing upon
the plate are provided a degree of stability. The movement
resistant elements may include springs, hydraulic cylinders,
pneumatic cylinders, electromagnetic solenoids, and the like.
Furthermore, in certain instances, the degree of resistance offered
by a movement resistant element may be adjusted, such as by
operation of a valve, so that the stability of the plate upon which
the subject stands may vary depending upon the needs of the
subject.
Inventors: |
Knecht; Stephen M; (Miami,
FL) ; Mak; Patrick; (Kowloon Bay, HK) ; Chan;
Scott; (Kowloon Bay, HK) ; Cheung; Leo;
(Kowloon Bay, HK) |
Correspondence
Address: |
WITHERS & KEYS, LLC
P. O. BOX 71355
MARIETTA
GA
30007-1355
US
|
Family ID: |
36684150 |
Appl. No.: |
11/911195 |
Filed: |
April 11, 2006 |
PCT Filed: |
April 11, 2006 |
PCT NO: |
PCT/US06/13510 |
371 Date: |
May 21, 2008 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
60670084 |
Apr 11, 2005 |
|
|
|
60719523 |
Sep 22, 2005 |
|
|
|
Current U.S.
Class: |
482/146 |
Current CPC
Class: |
A63B 22/18 20130101;
A63B 2022/0033 20130101; A63B 2208/0204 20130101; A63B 26/003
20130101; A61B 3/113 20130101 |
Class at
Publication: |
482/146 |
International
Class: |
A63B 22/16 20060101
A63B022/16 |
Claims
1. A stability platform, comprising: a base; a plurality of
movement resistant elements fixed to the base; a rigid plate
coupled to the movement resistant elements and pivotally coupled to
the base such that the movement resistant elements resist movement
of the plate relative to the base.
2. The stability platform of claim 1, wherein the plurality of
movement resistant elements comprise cylinders.
3. The stability platform of claim 2, wherein the cylinders are
hydraulic cylinders.
4. The stability platform of claim 3, wherein there are at least
four hydraulic cylinders, a first hydraulic cylinder is coupled to
a front portion of the plate, a second hydraulic cylinder is
coupled to a rear portion of the plate, a third hydraulic cylinder
is coupled to a left portion of the plate, and a fourth hydraulic
cylinder is coupled to a right portion of the base.
5. The stability platform of claim 4, wherein a top chamber of the
first hydraulic cylinder is hydraulically interconnected to a top
chamber of the second hydraulic cylinder, a bottom chamber of the
first hydraulic cylinder is hydraulically interconnected to a
bottom chamber of the second hydraulic cylinder, a top chamber of
the third hydraulic cylinder is hydraulically interconnected to a
top chamber of the fourth hydraulic cylinder, a bottom chamber of
the third hydraulic cylinder is hydraulically interconnected to a
bottom chamber of the fourth hydraulic cylinder.
6. The stability platform of claim 5, further comprising: a first
valve disposed within the hydraulic interconnection of the first
and second hydraulic cylinders; and a second valve disposed within
the hydraulic interconnection of the third and fourth hydraulic
cylinders.
7. The stability platform of claim 6, further comprising: a control
mechanically interconnected to the first and second valves, wherein
manipulation of the control adjusts the degree of opening of the
first and second valves.
8. The stability platform of claim 1, further comprising: a control
interconnected to the plurality of movement resistant elements,
wherein manipulation of the control adjusts the amount of
resistance provided by the plurality of movement resistant
elements.
9. The stability platform of claim 2, wherein the movement
resistant elements further comprise springs spaced about the
periphery of the plate.
10. The stability platform of claim 1, wherein the movement
resistant elements comprise springs spaced about the periphery of
the plate.
11. The stability platform, wherein the base comprises a step
adjacent to the plate.
12. The stability platform of claim 1, further comprising a first
vertically elongated member extending upward from the base.
13. The stability platform of claim 12, further comprising first
and second rails extending upward from opposing sides of the base
to a top portion of the first vertically elongated member.
14. The stability platform of claim 12, further comprising: a hub
fixed to the top of the first vertically elongated member; and a
second vertically elongated member extending upward from the top of
the first vertically elongated member, the second vertically
elongated member being rotatable about a longitudinal axis in
relation to the hub.
15. The stability platform of claim 14, further comprising: a
control disposed on the hub and interconnected to the plurality of
movement resistant elements, wherein manipulation of the control
adjusts the amount of resistance provided by the plurality of
movement resistant elements.
16. The stability platform of claim 12, further comprising at least
one shelf fixed to the first vertically elongated member.
17. The stability platform of claim 16, further comprising: a tilt
sensor coupled to the plate; and a computer located on the at least
one shelf, the computer being in electrical communication with the
tilt sensor.
18. The stability platform of claim 1, wherein each movement
resistant element includes a shaft with a pivotal connection to the
plate.
19. The stability platform of claim 18, wherein the pivotal
connection comprises: a retaining member having a first aperture of
a first diameter and having a second aperture of a second diameter
that is greater than the first diameter, the apertures being
concentric, the shaft of the movement resistant element extending
through the first and second apertures; first and second ball
bearings; and a bearing retaining disk having a disk diameter less
than the second diameter and larger than the first diameter, the
retaining disk having a channel on each side with the first ball
bearing seated in one channel of the retaining disk and with the
second ball bearing seated in the other channel of the retaining
disk, the retaining disk being disposed within the second aperture
and being movable within the second aperture, the retaining disk
having a ball and socket joint wherein a socket portion of the ball
and socket joint is fixed relative to the retaining disk while the
ball portion pivots relative to the socket, the ball portion being
affixed to the shaft of the movement resistant element.
20. A stability platform, comprising: a base; at least one movement
resistant element fixed to the base, the at least one movement
resistant element containing a flowing substance; a rigid plate
coupled to the at least one movement resistant element and
pivotally coupled to the base such that the movement resistant
elements resist movement of the plate relative to the base; and a
valve having adjustable positions and being in fluid communication
with the at least one movement resistant element such that the
position of the valve controls the degree of resistance created by
the at least one movement resistant element.
21. The stability platform of claim 20, wherein the at least one
movement resistant element is a hydraulic cylinder.
22. The stability platform of claim 20, further comprising a
control knob mechanically coupled to the valve such that rotation
of the control knob adjusts the position of the valve.
23. The stability platform of claim 20, further comprising a tilt
sensor coupled to the plate.
24. The stability platform of claim 20, wherein the at least one
movement resistant element has a shaft that has a pivotal
connection to the plate.
25. The stability platform of claim 24, wherein the pivotal
connection comprises: a retaining member having a first aperture of
a first diameter and having a second aperture of a second diameter
that is greater than the first diameter, the apertures being
concentric, the shaft of the movement resistant element extending
through the first and second apertures; first and second ball
bearings; and a bearing retaining disk having a disk diameter less
than the second diameter and larger than the first diameter, the
retaining disk having a channel on each side with the first ball
bearing seated in one channel of the retaining disk and with the
second ball bearing seated in the other channel of the retaining
disk, the retaining disk being disposed within the second aperture
and being movable within the second aperture, the retaining disk
having a ball and socket joint wherein a socket portion of the ball
and socket joint is fixed relative to the retaining disk while the
ball portion pivots relative to the socket, the ball portion being
affixed to the shaft of the movement resistant element.
26. A stability platform, comprising: a base; a rigid plate
pivotally coupled to the base; at least one movement resistant
element fixed to the base, the at least one movement resistant
element having a shaft that has a pivotal connection to the rigid
plate such that the movement resistant element resists movement of
the plate relative to the base.
27. The stability platform of claim 26, a valve having adjustable
positions and being in fluid communication with the at least one
movement resistant element such that the position of the valve
controls the degree of resistance created by the at least one
movement resistant element.
28. The stability platform of claim 26, wherein the pivotal
connection comprises: a retaining member having a first aperture of
a first diameter and having a second aperture of a second diameter
that is greater than the first diameter, the apertures being
concentric, the shaft of the movement resistant element extending
through the first and second apertures; first and second ball
bearings; and a bearing retaining disk having a disk diameter less
than the second diameter and larger than the first diameter, the
retaining disk having a channel on each side with the first ball
bearing seated in one channel of the retaining disk and with the
second ball bearing seated in the other channel of the retaining
disk, the retaining disk being disposed within the second aperture
and being movable within the second aperture, the retaining disk
having a ball and socket joint wherein a socket portion of the ball
and socket joint is fixed relative to the retaining disk while the
ball portion pivots relative to the socket, the ball portion being
affixed to the shaft of the movement resistant element.
Description
RELATED APPLICATIONS
[0001] The present application claims priority to U.S. Provisional
Application 60/670,084, filed on Apr. 11, 2005, and entitled
BALANCE AND VESTIBULAR DISORDER DIAGNOSIS AND REHABILITATION, which
is incorporated herein by reference. The present application also
claims priority to U.S. Provisional Application 60/719,523, filed
on Sep. 22, 2005, and entitled BALANCE AND VESTIBULAR DISORDER
DIAGNOSIS AND REHABILITATION, which is also incorporated herein by
reference.
TECHNICAL FIELD
[0002] The present application is related to postural stability.
More particularly, the present application is related to platforms
for assessing and/or rehabilitating postural stability.
BACKGROUND
[0003] For various reasons, subjects may have the need to assess
and/or rehabilitate their balance. For example, professional
athletes may wish to improve their balance in order to improve
their performance in their chosen sport. As another example,
subjects suffering from medical conditions such as vestibular,
orthopedic, neuromuscular, or neurological disorders may improve
their medical condition through balance assessment and
rehabilitation.
[0004] Attempts have been made to manufacture postural stability
platforms. However, these platforms may have drawbacks. For
example, these platforms include a plate upon which the subject
stands. This plate is suspended by an air bladder that is inflated
and deflated by an air compressor. Among other problems that may
arise, the air bladder and the air compressor are subject to
malfunctions or failure. Furthermore, the support provided by the
air bladder may be less than ideal.
SUMMARY
[0005] Embodiments of the present invention address these issues
and others by providing stability platforms that utilize one or
more movement resistant elements such as hydraulic cylinders and/or
springs to provide stability to the plate upon which the subject
stands. Furthermore, in certain embodiments the degree of
resistance to movement offered by the movement resistant elements
is controllable, such as by a control knob that controls a position
of a valve or other restrictive element that alters the resistance
to movement.
[0006] One embodiment is a postural stability platform that
includes a base and a plurality of movement resistant elements
fixed to the base. The postural stability platform further includes
a rigid plate coupled to the movement resistant elements and
pivotally coupled to the base such that the movement resistant
elements resist movement of the plate relative to the base.
[0007] Another embodiment is a stability platform that includes a
base and at least one movement resistant element fixed to the base,
the at least one movement resistant element containing a flowing
substance. The postural stability platform further includes a rigid
plate coupled to the at least one movement resistant element and
movably coupled to the base such that the movement resistant
elements resist movement of the plate relative to the base. The
postural stability platform also includes a valve having adjustable
positions and being in fluid communication with the at least one
movement resistant element such that the position of the valve
controls the degree of resistance created by the at least one
movement resistant element.
[0008] Another embodiment is a postural stability platform that
includes a base and a rigid plate pivotally coupled to the base.
The postural stability platform further includes at least one
movement resistant element fixed to the base, the at least one
movement resistant element having a shaft that is pivotally coupled
to the rigid plate such that the movement resistant element resists
movement of the plate relative to the base.
DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 shows a front perspective view of one embodiment of a
stability platform.
[0010] FIG. 2 shows a rear perspective view of one embodiment of a
stability platform.
[0011] FIG. 3 shows an exploded view of a center hub of one
embodiment.
[0012] FIG. 4 shows a partially exploded view of a base of one
embodiment.
[0013] FIG. 5 shows an exploded view of a cylinder head of the one
embodiment.
[0014] FIG. 6 shows a cross-sectional view of the cylinder head of
one embodiment.
[0015] FIG. 7 shows a cross-sectional view of a center post of one
embodiment
[0016] FIG. 8 shows an exploded view of a valve control system of
one embodiment.
[0017] FIG. 9 shows a schematic of a hydraulic system of one
embodiment.
DETAILED DESCRIPTION
[0018] Embodiments of postural stability platforms provide one or
more movement resistant elements to provide support for the subject
standing on a balance plate of the platform. The one or more
movement resistant elements may be cylinders that include shafts
coupled to the balance plate. In certain embodiments, multiple
movement resistant elements are present to provide stability in a
number of directions of movement of the balance plate. In certain
embodiments, one or more adjustable valves are present so that the
adjustment to the valve alters the degree of resistance to
movement.
[0019] FIGS. 1 and 2 show one embodiment of a postural stability
platform 100. The platform 100 of this example includes many
external features. The platform 100 includes a base assembly 102
that has a balance plate 104 coupled thereto. The balance plate 104
is movable relative to the base assembly 102 by the balance plate
104 having a pivot point at or near its center. The details of the
pivot point of the balance plate 104 are discussed in more detail
below. The balance plate 104 may include a non-skid sheet to
prevent subjects from slipping. An example of such a non-skid sheet
is the Safety-Walk.RTM. model 370 medium grade non-skid sheet by 3M
Co. of St. Paul, Minn. The balance plate 104 of this example may be
made of various rigid materials, such as metal, plastic such as
acrylonitrile butadiene styrene (ABS), wood, and so forth. The size
of the balance plate 104 is a matter of design choice but the
diameter should exceed the largest expected foot size so that the
foot of a subject can be entirely located atop the balance plate
104.
[0020] The base assembly 102 of this particular example includes
various other features as well, such as individual sections 148,
top cover plates 149, non-skid sheets 150 applied to the top cover
plates 149, and removable plugs 152. The individual sections 148
allow for the base to be easily disassembled into pieces,
transported, and reassembled. These individual sections 148 of this
example may be made of similar rigid materials to the balance plate
104. The top cover plates 149 of this example, which may of similar
materials to the sections 148, overlap between the individual
sections to help hold the sections together. The non-skid sheet 150
may be included so that a subject does not slip when stepping onto
and off of the base assembly 102. The plugs 152 may be included to
plug holes provided in the top cover plates 149. The plugs 152 may
be removed so that caster wheel assemblies can be accessed within
the base assembly 102 in order to lower or raise the caster wheel
assemblies and either mobilize or immobilize the stability platform
100.
[0021] To provide support, a member 106 is included that is mounted
to the base assembly 102 and extends vertically. The member 106 of
this example may be constructed of a rigid material, such as steel
or wood, and is attached within the base assembly 102 to a rigid
base discussed below. The member 106 provides a stable point upon
which left and right support rails 112, 114 can attach. The support
rails 112, 114 attach to the base assembly 102 and then extend
vertically to attach to a hub 108 mounted atop the member 106. The
support rails 112, 114 may be made of various rigid materials such
as metal or wood, and these support rails may include a soft
covering such as foam rubber, neoprene, etc. to provide a
comfortable hand-hold for a subject to use when stepping onto and
off of the base assembly 102 and when steadying oneself while
standing on the balance plate 104.
[0022] In this example, the hub 108 acts as a point of attachment
for the support rails 112, 114 and also for a display mast 118. The
hub 108 may be constructed of a rigid material such as metal, wood
and so forth and may have a shell made of ABS or other plastics or
similar materials. A mounting bracket 116 is attached to the hub to
allow the display mast 118 to be mounted in a movable relationship
with the hub 108. In this example, the mounting bracket 116 swivels
within a hole 138 (shown in FIG. 3) of the hub 108. Furthermore,
the bracket 116 has the ability to rotate forward and backward
relative to the hub 106. Thus, a video display device 120, such as
a liquid crystal display (LCD) screen, can be swiveled to be viewed
from the front side or the rear side of the platform 100 and can be
rotated forward or backward to improve the angle of viewing. The
video display device 120 is attached to the mast 120 via a mounting
bracket 136, which also allows the vertical position of the video
display device 120 to be altered to adapt to subjects of different
heights.
[0023] The video display device 120 of this example may be used for
various purposes. For example, information about the subject may be
displayed. A graphical user interface may be displayed to allow an
operator and/or the subject to make selections regarding performing
various balance assessment or rehabilitation routines and so forth.
Graphical displays may then be provided for viewing by the subject
while balancing on the balance plate 104 to produce a response by
the subject to thereby assess and/or rehabilitate the balance of
the subject.
[0024] The stability platform 100 of this particular example is
self-contained in that the display 136 as well as corresponding
computer equipment is attached to the platform 100. The computer
equipment of this embodiment includes a central processing unit
(CPU) 124 held in place by a bracket 122 that is attached to the
member 106. The CPU 124 is interconnected to the display device 120
to produce the visual displays for the operator and subject to
view. The CPU 124 is also connected to a printer 128 resting on a
shelf 126 that is attached to the member 106. The printer 128 can
be used to print information about the subject and the assessment
and/or rehabilitation session.
[0025] The CPU 124 is also connected to input devices such as a
keyboard 132 and mouse 134 that both rest on a shelf 130 that is
attached to the member 106. The keyboard 132 and mouse 134 allows
the operator and/or subject to interact with the graphical user
interface. Other interface devices are applicable as well, such as
remote controls that enables the operator to stand at a distance
from the platform and also stand on the front side of the platform
so that both the operator and the subject can simultaneously view
the display device 120.
[0026] The CPU 124 may also be connected to a tilt sensor that is
mounted to the balance plate 102. The tilt sensor is discussed in
more detail below. However, the CPU 124 may receive data from the
tilt sensor that specifies the attitude of the balance plate 104
such that the CPU may monitor the movement of the balance plate
104. Thus, the subject may be given visual feedback of the movement
of the balance plate 104 via the display device 120 and this
assessment and/or rehabilitation data may be stored for later
review or comparison.
[0027] In order to accommodate subjects of varying degrees of
balance control, the platform 100 of this embodiment includes a
mechanism for controlling how stable the balance plate 104 is. For
a subject with very poor balance, it is likely necessary to assist
the subject by providing a significant amount of stability to the
balance plate 104 so that the balance plate 104 does not make large
and sudden changes in position that could lead to ineffective
assessment and/or rehabilitation sessions.
[0028] The mechanism of this example includes a control know 110
mounted upon the hub 108. As shown in FIG. 3, a center rod 140
passes up through the bottom of the hub 108. This center rod 140
extends down the member 106 and into the base where it is then
connected to a gear assembly as discussed below. At the hub 108,
the center rod 140 has a pin 141 running perpendicularly through
it, and a metal insert 142 fits over the rod 140 and couples to the
pin 141. A spring 146 and ball 145 are positioned between the metal
insert 142 and a plate 139 having holes 143. The knob 110 fits over
the metal insert 142 and thereby is coupled to the center rod 140
such that rotation of the knob 110 results in rotation of the
center rod 140.
[0029] As discussed below, there may be various stability settings
that can be selected by the knob 110. To provide for these
settings, the spring-biased ball 145 rests in one of the holes 143
of the plate 139. Each hole 143 corresponds to a different
stability setting as they center rod 140 must be rotated to move
the ball 145 from one hole 143 to another. Markings may be provided
on the plate 139 to illustrate the different settings, such as 0-11
plus a lock as the 12.sup.th position. Zero indicates a free
balance plate 104 having the least stability. The lock at the
12.sup.th position indicates fixed balance plate 104 having
complete stability for purposes of stepping onto and off of the
balance plate 104.
[0030] As shown in FIG. 4, the base assembly 102 includes the
individual sections 148, each having an internal support structure
154 that includes holes for receiving the member 106 and for
allowing the caster wheel assemblies 174 to be accessed. The
torus-like shape of sections 148 rests upon and is fixed to a base
plate 156.
[0031] The base plate 156 includes holes 182 that allow caster
wheels 180 to be raised and lowered to immobilize or mobile that
platform 100. The caster wheels 180 are suspended by a bracket 176
mounted to the base plate 156 and having a bolt 178 threaded into
it. The bolt 178 is coupled to the caster wheel 180 and extends up
through the hole of section 148 to be exposed upon removal of the
plug 152. Turning the bolt 178 causes the caster wheel 180 to be
raised or lowered.
[0032] The stabilization mechanism of this example also includes a
set of movement resistant elements that are coupled to the base
plate 156 and to the balance plate 104. The movement resistant
elements may be of many forms. Some examples include springs,
hydraulic cylinders, pneumatic cylinders, electromagnetic
solenoids, and the like. As shown in this example, there are a set
of cylinders 170, 196, 197, and 198. These cylinders may be
hydraulic or pneumatic in nature. In this example, each of these
cylinders includes a cylinder head 172 which pivotally coupled each
cylinder to a support plate 158. The balance plate 104 is then
mounted to the support plate 158. Examples of the cylinder head 172
and a hydraulic system are discussed in more detail below.
[0033] The support plate is suspended over the base plate 156 by a
center post 199 having a post head assembly 195 that also attached
to the support plate 158. The center post 199 provides a ball and
socket type of joint with the post head assembly 195 as seen in
FIG. 7. Thus, the support plate 158, and hence the balance plate
104, is free to pivot over a 360 degree range relative to the base
plate 156, and thus relative to the entire base assembly 102. While
this example provides for a pivotal connection of the support plate
158 that allows for a full 360 degrees of movement, the pivotal
connection could be limited such as to a single axis in other
embodiments. For example, the pivotal connection could restrict
movement to an anterior-posterior axis of rotation of the balance
plate 104, or like wise, a left-right axis of rotation.
[0034] In addition to the cylinders 170, 196, 197, and 198, this
example provides a spring assembly 160 including springs 166, 168
spaced about a peripheral set of rings 162, 164. The lower ring 164
is mounted via a bracket 165 to the base plate 156. The balance
plate 104 rests upon the upper ring 162. The springs 166, 168
provide additional movement resistance but once compressed, assist
the subject in returning the balance plate 104 to its neutral
position.
[0035] As shown, the springs alternate in length with one spring
168 having a greater length that extends from the upper ring 162 to
the lower ring 164 while adjacent rings 166 have a shorter length
such that compression of the longer spring 168 must take place
prior to the shorter adjacent springs 166 becoming a factor in the
movement of the subject. One example of springs are made of
stainless steel of a gauge of 2.6 millimeters, a pitch of 10
degrees, and an inside diameter of 47 millimeters. In one
embodiment, the longer spring 168 is 170 millimeters in
uncompressed length while the shorter spring 166 is 100 millimeters
in uncompressed length.
[0036] Additional springs (not shown) may be included such as by
placing them nearby the cylinders and coupling them to the base
plate 158. Furthermore, skirts (not shown) may be placed on the
inside and/or outside of the rings 162, 164 to help support the
springs hold them in place between the rings 162, 164.
[0037] In order to limit the amount of travel of the balance plate
104, posts 171 may be included and spaced about the periphery.
These posts 171 limit the amount of movement possible by the
support plate 158. A torus-like rubber bumper (not shown) may be
positioned atop the posts 171 to provide 360 degrees of potential
contact zones for the support plate 158.
[0038] A tilt sensor 105 is mounted to the support plate 158 so
that data signals are produced that are indicative of the attitude
of the balance plate 104 upon which the subject is standing. As
discussed above, a computer system may receive these data signals
and use them to provide immediate visual feedback to the subject,
to compute characteristics of the balance capabilities of the
subject, and to store for later review and analysis. The tilt
sensor 105 may be of various types. One example is the SQ-SI-360DA
Solid-State MEMS Inclinometer by Signal Quest of Lebanon, N.H.
[0039] Returning to hydraulic system of this particular example,
FIGS. 5 and 6 show a cylinder head assembly 172. The hydraulic
cylinder 170 has a shaft 171 that extends vertically. Atop the
shaft 171 sits a ball 186 and socket 184 joint that has external
threads. A retaining member 188 has two concentric apertures of
differing diameters. The smaller diameter aperture faces the
cylinder 170 while the larger diameter aperture faces the support
plate 158. The smaller diameter aperture has a diameter larger than
that of the connection of the socket join to the shaft 171.
[0040] A first ball bearing 190 that has a diameter smaller than
the large diameter aperture but larger than the small diameter
aperture sits within the large diameter aperture of the retaining
member 188. A ball bearing retaining disk 192 has a channel on each
side and sits atop the first ball bearing 190 with the first ball
bearing 190 being positioned within the bottom channel. A second
ball bearing 194 sits atop the ball bearing retaining disk 192 and
is positioned within the top channel. The retaining disk 192 has a
threaded aperture that is tightened upon the threads of the socket
184. The retaining disk 192 also sits within the large diameter
aperture of the retaining member 188. The retaining disk 192 has a
smaller outside diameter than the diameter of the large aperture of
the retaining member 188 which allows the retaining member 188 to
have 360 degrees of movement relative to the shaft 171.
[0041] The retaining member 188 directly attaches to the support
plate 158. In doing so, the top ball bearings 194 contact the
underside of the support plate 158 while the bottom ball bearings
contact the retaining member 188 to thereby maintain a snug
coupling of the shaft 171 to the support plate 158 while also
allowing the support plate 158 to change its angle relative to the
shaft 171 without binding.
[0042] Returning to the mechanism for controlling the amount of
stability provided to the balance plate 104, the connection of the
center rod 140 to adjustable valves 202, 204 is shown in FIG. 8.
The center rod 140 extends down the member 106 until it reaches the
interior of the particular base section 148 upon which the member
106 is mounted. Within that particular base section 148, a gearbox
assembly 201 is included to interconnect the center rod 140 to the
adjustable valves 202, 204.
[0043] In this example, the gearbox includes a large drive gear 240
that is coupled to the center rod 140 via a ring 238, a washer 242,
and a clamp 244. Two smaller diameter spur gears 234, 236 are
coupled to the shafts of the valves 204, 202 respectively to
thereby provide a gear amplification from the center rod 140 to the
valves 202, 204. In one example, the large drive gear 240 has a
diameter of 102 millimeters while the spur gears 234, 236 have a
diameter of 18 millimeters. The center rod 140, valves 202, 204,
gears 234, 236 are held in place by a support plate 232 and a
mounting bracket 230 that is fixed to the base section 148.
[0044] Thus, rotation of the center rod 140 results in rotation of
the control shafts of the valves 202, 204 to thereby change the
degree to which the fluid channel of the valves 202, 204 is open.
As the degree of opening increases, the resistance to the flow of
fluid decreases. The resistance of the flow of the fluid provides
the resistance to movement of the balance plate 104. As discussed
above, in one embodiment the control knob 110 has 12 positions,
ranging from completely open valves and a free balance plate 104 to
completely closed valves and a fixed balance plate 104.
[0045] FIG. 9 illustrates the hydraulic configuration of this
example. It will be appreciated that there are other configurations
possible, involving either fewer or more cylinders, fewer or more
valves, and so forth. For example, there could be a single cylinder
used for the anterior-posterior axis and a single cylinder used for
the left-right axis. It will also be appreciated that the routing
of the fluid lines may be changed. As shown, the top chamber of a
cylinder of one axis is in fluid communication with the top chamber
of an opposite cylinder of the same axis, and the likewise for the
bottom chambers. It will be appreciated that the top chamber of a
cylinder could instead be in fluid communication with a bottom
chamber of the same cylinder, especially where a single cylinder is
used for a given axis.
[0046] In this particular example shown, the valve 202 is located
in the fluid pathway between a bottom chamber 208 of cylinder 196
and bottom chamber 216 of cylinder 198. This provides resistance in
the anterior-posterior axis of movement. Likewise, the valve 204 is
located in the fluid pathway between a bottom chamber 218 of
cylinder 197 and a bottom chamber 212 of cylinder 170. This
provides resistance in the left-right axis of movement. The top
chamber 206 of cylinder 196 is in fluid communication with the top
chamber 214 of cylinder 198 while the top chamber 220 of cylinder
197 is in fluid communication with the top chamber 210 of cylinder
170. The hydraulic hoses 229 that provide the fluid pathways are
placed within the base assembly 102 and may be routed between the
springs 166, 168.
[0047] This particular example also includes various three-way
connectors 222, 224, 226, and 228 that have valves as well. These
three-way connectors with valves allows the hydraulic fluid to be
injected into the fluid channels to fill the hoses 229 each of the
chambers of the cylinders 170, 196, 197, and 198. One example of
such hydraulic fluid is the Tellus.RTM. 37 weight oil by Shell Oil
Co., of Houston, Tex. Pressure gauges may be connected to these
three-way connectors 222, 224, 226, and 228 with valves to
pressurize the hydraulic system and to bleed away trapped air
within the hydraulic system. For example, the hydraulic system may
be pressurized to 150 pounds per square inch and then the balance
plate 104 may be worked for about 30 minutes to bleed the air from
the hydraulic system.
[0048] Examples of the components of the hydraulic system of FIG. 8
include model 160S-16SD25N50 hydraulic cylinders by TAIYO LTD of
Osaka, Japan. Other examples include model FT1251 proportional
valves and high pressure hoses by Kam Kee of Hong Kong.
[0049] While the invention has been particularly shown and
described with reference to various embodiments thereof, it will be
understood by those skilled in the art that various other changes
in the form and details may be made therein without departing from
the spirit and scope of the invention
* * * * *