U.S. patent application number 13/417925 was filed with the patent office on 2013-01-10 for refreshable braille display device.
Invention is credited to Hanna Francis Bawab, Patrick Doll, Daniel Charles Minnich, Jarrod Robertson.
Application Number | 20130011816 13/417925 |
Document ID | / |
Family ID | 42272703 |
Filed Date | 2013-01-10 |
United States Patent
Application |
20130011816 |
Kind Code |
A1 |
Minnich; Daniel Charles ; et
al. |
January 10, 2013 |
Refreshable Braille Display Device
Abstract
Disclosed is a refreshable Braille display device comprised of a
rotary character display assembly which can display a refreshable
Braille character in the plane of the rotary display assembly. Also
disclosed is a method of displaying a refreshable Braille
character.
Inventors: |
Minnich; Daniel Charles;
(Chattanooga, TN) ; Bawab; Hanna Francis;
(Toronto, CA) ; Robertson; Jarrod; (Bloomfield
Hills, MI) ; Doll; Patrick; (Cincinnati, OH) |
Family ID: |
42272703 |
Appl. No.: |
13/417925 |
Filed: |
March 12, 2012 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
12820922 |
Jun 22, 2010 |
8133055 |
|
|
13417925 |
|
|
|
|
11567700 |
Dec 6, 2006 |
7744372 |
|
|
12820922 |
|
|
|
|
60748003 |
Dec 6, 2005 |
|
|
|
Current U.S.
Class: |
434/113 |
Current CPC
Class: |
G09B 21/02 20130101;
G09B 21/003 20130101 |
Class at
Publication: |
434/113 |
International
Class: |
G09B 21/00 20060101
G09B021/00 |
Claims
1. A refreshable Braille display device comprising, a Braille
character display assembly comprising: a lower rotary plate
defining a plurality of lower bearing wells, each lower bearing
well configured to house a bearing; an upper rotary plate having a
substantially planar reading surface and defining a plurality of
upper bearing wells configured to receive a bearing, the upper
rotary plate being positioned in overlying registration with and
connected to the lower rotary plate such that each upper bearing
well is in overlying registration with one of the plurality of
lower bearing wells to provide a plurality of bearing chambers,
wherein the plurality of bearing chambers each have a bearing
disposed therein and form at least one Braille character cell array
configured to rotate about, and in a plane substantially
perpendicular to, a rotary axis; and a stationary plate disposed
between the lower and upper rotary plates and defining a plurality
of apertures configured to selectively allow communication between
the respective bearing wells when a lower bearing well and an upper
bearing well are each positioned in registration with one of the
plurality of apertures; and a means for selectively positioning the
bearing in at least one bearing chamber in the respective upper or
lower bearing wells of the character cell array when communication
between the respective bearing wells is selectively allowed.
2. The refreshable Braille display device of claim 1, wherein the
at least one Braille character cell array is comprised of an array
of at least six bearing chambers.
3. The refreshable Braille display device of claim 2, wherein the
character display assembly comprises at least two Braille character
cells arranged radially about, and in a plane substantially
perpendicular to, the rotary axis.
4. The refreshable Braille display device of claim 1, wherein the
upper rotary plate has a thickness less than the diameter of the
bearing housed within the bearing chambers.
5. The refreshable Braille display device of claim 1, wherein the
lower rotary plate has a thickness equal to or greater than the
diameter of the bearing housed within the bearing chambers.
6. The refreshable Braille display device of claim 1, wherein at
least three pass through apertures are formed by the stationary
divider plate.
7. The refreshable Braille display device of claim 1, wherein the
bearings are comprised of a magnetic metal.
8. The refreshable Braille display device of claim 1, wherein the
means for selectively positioning the bearing in at least one
bearing chamber in the respective upper or lower bearing wells
comprises an electromagnet registered with at least one of the
plurality of pass through apertures of the stationary divider
plate.
9. The refreshable Braille display device of claim 6, wherein the
means for selectively positioning the bearing in at least one
bearing chamber in the respective upper or lower bearing wells
comprises at least three electromagnets and wherein each of the at
least three electromagnets is registered with one of the at least
three pass through apertures of the stationary divider plate.
10. The refreshable Braille display device of claim 1, further
comprising a means for regulating the selective positioning of the
bearings within the bearing chambers.
11. The refreshable Braille display device of claim 2, wherein the
means for regulating comprises a light source, a light detector,
and timing plate configured to selectively allow light to
communicate from the light source to the light detector.
12. The refreshable Braille display device of claim 11, wherein the
means for regulating comprises at least three light sources and at
least three light detectors, and wherein each light detector is
configured to selectively detect light from one of the at least
three light sources.
13. The refreshable Braille display device of claim 1, further
comprising a flexible bearing retention layer disposed on the
planar reading surface of the upper rotary plate.
14. The refreshable Braille display device of claim 13, wherein the
flexible bearing retention layer is comprised of latex.
15. The refreshable Braille display device of claim 1, further
comprising a means for mechanically rotating the display assembly
about the rotary axis at a predetermined rate of rotation.
16. A method for displaying a refreshable Braille character,
comprising: a) providing a substantially planar Braille character
display assembly comprising a plurality of bearing chambers,
wherein the plurality of bearing chambers each have a bearing
disposed therein and form a plurality of Braille character cell
arrays configured to rotate about, and in a plane substantially
perpendicular to, a rotary axis; b) positioning at least one of the
plurality of bearing chambers of the Braille character cell array
in registration with a means for selectively positioning a bearing;
c) selectively positioning the bearing in the bearing chamber of
step b) in an upper portion of the bearing chamber to display a
raised Braille character dot; and d) maintaining the selectively
positioned bearing of step c) in the upper portion of the bearing
chamber while the substantially planar Braille character display
assembly is rotated at least one revolution about the rotary
axis.
17. The method of claim 16, wherein the at least one bearing
chamber of step b) is selectively positioned in registration with
the selective positioning means by rotating the substantially
planar Braille character display assembly about the rotary
axis.
18. The method of claim 16, wherein the bearing of step c) is
selectively positioned in the respective upper bearing well by
applying an electromagnetic force to the bearing.
19. The method of claim 16, further comprising repeating steps b),
c), and d) until a plurality of bearings are selectively positioned
in the respective upper portions of the respective bearing chambers
to display a desired Braille character.
20. The method of claim 16, further comprising refreshing the
selectively positioned bearing of step c) by selectively
positioning the bearing in a lower portion of the bearing chamber
after the bearing chamber has made at least one complete revolution
about the rotary axis.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of and claims the benefit
of priority to co-pending U.S. patent application Ser. No.
12/820,922, filed Jun. 22, 2010, which application is a
continuation of U.S. patent application Ser. No. 11/567,700, filed
Dec. 6, 2006, which application claims the benefit of priority to
U.S. Provisional Patent Application Ser. No. 60/748,003; filed Dec.
6, 2005. The entire disclosures of these patent applications are
incorporated by reference herein for all purposes.
FIELD OF THE INVENTION
[0002] The present invention relates generally to the field of
refreshable Braille display devices and more particularly to a
refreshable Braille display device comprised of a rotary display
assembly.
BACKGROUND OF THE INVENTION
[0003] Braille is the language of visually impaired readers whose
vision is impaired to the extent that they cannot read printed
material. Reading Braille relies on the sense of touch, where
reading is done by running a finger over a combination of
characters. This method was invented by Louise Braille (1809-1852)
in 1821 at the age of 12. Louise Braille became visually impaired
at the age of 3 and developed this method to enable him to live
equally with the people around him.
[0004] A typical Braille character is comprised of six raised pins
or bumps in a Braille cell grid having three rows high and two
columns wide. Different combinations of the six pins represent
different characters. In other applications, a Braille cell may be
comprised of 8 or more Braille dots arranged in a grid four or more
rows high and two columns wide. For example, the word "hello" in a
typical six pin Braille cell is shown below.
##STR00001##
[0005] Refreshable Braille Displays (RBDs) are devices that allow
visually impaired readers to review work or read material, which an
enabled reader can do on a computer screen. Refreshable Braille
Displays range in terms of the number of characters presented on
one line, but most standard displays can present in the range of
from 40 to 80 cell characters.
[0006] Unfortunately, many visually-impaired citizens around the
country are forced to use the traditional audio device method to
review work or read material due to the scarce supply and high cost
of RBD's. This problem stems from the fact that the Braille
displays currently on the market are very expensive to produce and
maintain. These devices typically utilize a dedicated Piezoelectric
crystal actuator for each raised character dot in a cell grid.
These Piezoelectric actuators expand when an electric potential is
applied to them, producing a change in the mechanism leading to a
protruding bump. Repairs are also expensive and inconvenient
because they require the user to relinquish their unit for the
duration of the repair and because of the complexity and intricacy
of the Piezoelectric actuators of the RBD unit itself.
[0007] Improvement in such devices producing computer-refreshable
Braille text for tactile reading by the blind and visually impaired
could thus be utilized thereby broadening accessibility to computer
services such as electronic books, e-mail and other network access,
and general computer use. Improvements in cost and mechanical
reliability must be attained in order to facilitate more widespread
use of refreshable Braille devices. Thus, there is a need in the
art for a refreshable Braille display device which can reduce the
overall cost to the consumer and still accurately display and
refresh a set of Braille characters, occupy less space than
existing RBDs, be easy to clean, be tactilely and aesthetically
pleasing, and produce no objectionable noise.
SUMMARY OF THE INVENTION
[0008] The present invention is based, in part, upon the invention
of an improved refreshable Braille display device comprised of a
rotary character display assembly which can display any desired
number of refreshable Braille characters in the plane of the rotary
display assembly.
[0009] In one aspect, the refreshable Braille display device
comprises a Braille character display assembly having a lower
rotary plate defining a plurality of lower bearing wells, each
lower bearing well configured to house a bearing; an upper rotary
plate having a substantially planar reading surface and defining a
plurality of upper bearing wells configured to receive a bearing,
the upper rotary plate being positioned in overlying registration
with and connected to the lower rotary plate such that each upper
bearing well is in overlying registration with one of the plurality
of lower bearing wells to provide a plurality of bearing chambers,
wherein the plurality of bearing chambers each have a bearing
disposed therein and form at least one Braille character cell array
configured to rotate about, and in a plane substantially
perpendicular to, a rotary axis. A stationary divider plate is
disposed between the lower and upper rotary plates and defines a
plurality of apertures configured to selectively allow
communication between the respective bearing wells when a lower
bearing well and an upper bearing well are each positioned in
registration with one of the plurality of apertures. A means is
also provided for selectively positioning the bearing in at least
one bearing chamber in the respective upper or lower bearing wells
of the character cell array when communication between the
respective bearing wells is selectively allowed.
[0010] In another aspect, the present invention provides a method
of displaying a refreshable Braille character. The method generally
comprises providing a substantially planar Braille character
display assembly comprising a plurality of bearing chambers,
wherein the plurality of bearing chambers each have a bearing
disposed therein and form a plurality of Braille character cell
arrays configured to rotate about, and in a plane substantially
perpendicular to, a rotary axis; positioning at least one of the
plurality of bearing chambers of the Braille character cell array
in registration with a means for selectively positioning a bearing;
selectively positioning the bearing in the bearing chamber in an
upper portion of the bearing chamber to display a raised Braille
character dot; and maintaining the selectively positioned bearing
of step c) in the upper portion of the bearing chamber while the
substantially planar Braille character display assembly is rotated
at least one revolution about the rotary axis.
[0011] Additional aspects of the invention will be set forth, in
part, in the detailed description, and any claims which follow, and
in part will be derived from the detailed description, or can be
learned by practice of the invention. It is to be understood that
both the foregoing general description and the following detailed
description are exemplary and explanatory only and are not
restrictive of the invention as disclosed and/or as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The accompanying drawings, which are incorporated in and
constitute a part of this specification, illustrate certain aspects
of the instant invention and together with the description, serve
to explain, without limitation, the principles of the invention.
Unless indicated otherwise, like numerals represent like
elements.
[0013] FIG. 1 is a perspective view of an exemplary refreshable
Braille display device according to one aspect of the present
invention.
[0014] FIG. 2 is an exploded perspective view of an exemplary
Braille character display assembly according to one aspect of the
present invention.
[0015] FIG. 3 is a schematic cutaway side view of an exemplary
Braille character display assembly according to one aspect of the
present invention.
[0016] FIG. 4 is schematic top view of an exemplary stationary
divider plate according to one aspect of the present invention.
[0017] FIG. 5 a perspective view of an exemplary refreshable
Braille display device according to one aspect of the present
invention.
[0018] FIG. 6 is top view of an exemplary timing plate according to
one aspect of the present invention.
[0019] FIG. 6a is a close up illustration of the exemplary timing
apertures as shown in FIG. 6
[0020] FIG. 6b is an in illustration of exemplary timing apertures
having a tapered configuration in a circumferential direction.
[0021] FIG. 7 is an illustration of an exemplary refreshable
Braille device comprising a means for timing or regulating the
selective positioning of a character bearing according to one
aspect of the present invention.
[0022] FIG. 8 is schematic cutaway side view of an exemplary light
detection assembly according to one aspect of the present
invention.
[0023] FIG. 9 is a schematic wiring diagram according to one aspect
of the present invention.
[0024] FIG. 10 is an exploded perspective view of an exemplary
refreshable Braille display device comprising a base assembly
according to one aspect of the present invention.
[0025] FIGS. 11a-11g schematically illustrate a sequence of the
activation of all six Braille dots in a single Braille cell
according to one aspect of the present invention.
[0026] FIG. 12 is an exemplary illustration of the variable in
Equation (I).
[0027] FIG. 13 is an illustration of the two unknowns r and .theta.
being solved according to Equation (II).
[0028] FIG. 14 is a free-body diagram of an accelerating ball
bearing according to Equation (VII).
DETAILED DESCRIPTION OF THE INVENTION
[0029] The present invention can be understood more readily by
reference to the following detailed description, examples, and
claims, and their previous and following description. However,
before the present compositions, devices, and/or methods are
disclosed and described, it is to be understood that this invention
is not limited to the specific articles, devices, and/or methods
disclosed unless otherwise specified, as such can, of course, vary.
It is also to be understood that the terminology used herein is for
the purpose of describing particular aspects only and is not
intended to be limiting.
[0030] The following description of the invention is provided as an
enabling teaching of the invention in its best, currently known
embodiment. To this end, those skilled in the relevant art will
recognize and appreciate that many changes can be made to the
various aspects of the invention described herein, while still
obtaining the beneficial results of the present invention. It will
also be apparent that some of the desired benefits of the present
invention can be obtained by selecting some of the features of the
present invention without utilizing other features. Accordingly,
those who work in the art will recognize that many modifications
and adaptations to the present invention are possible and can even
be desirable in certain circumstances and are a part of the present
invention. Thus, the following description is provided as
illustrative of the principles of the present invention and not in
limitation thereof.
[0031] As used herein, the singular forms "a," "an" and "the"
include plural referents unless the context clearly dictates
otherwise. Thus, for example, reference to a "ball bearing"
includes aspects having two or more such ball bearings unless the
context clearly indicates otherwise.
[0032] Ranges can be expressed herein as from "about" one
particular value, and/or to "about" another particular value. When
such a range is expressed, another aspect includes from the one
particular value and/or to the other particular value. Similarly,
when values are expressed as approximations, by use of the
antecedent "about," it will be understood that the particular value
forms another aspect. It will be further understood that the
endpoints of each of the ranges are significant both in relation to
the other endpoint, and independently of the other endpoint.
[0033] As used herein, the terms "optional" or "optionally" mean
that the subsequently described event or circumstance may or may
not occur, and that the description includes instances where said
event or circumstance occurs and instances where it does not.
[0034] As summarized above, the present invention provides a
refreshable Braille display device comprised of a rotary character
display assembly which can display a refreshable Braille character
in the plane of the rotary display assembly. With reference to FIG.
1, an exemplary refreshable Braille display device 100 is shown.
The exemplified display device generally comprises a rotary display
assembly 200 configured to rotate about, and in a plane
substantially perpendicular to, a rotary axis R. The rotary display
assembly is configured to display a plurality of refreshable
Braille character cells 210 that can rotate about the rotary axis
and in the plane of the rotary display assembly.
[0035] As shown in FIG. 2, the rotary display assembly 200 is
comprised of a lower rotary plate 220 having a plurality of lower
bearing wells 222 formed therein. Each lower bearing well is
configured to house one of a plurality of bearings 230. An upper
rotary plate 240, having a plurality of upper bearing wells 242
configured to received one of the plurality of bearings, is
positioned in overlying registration with the lower rotary plate.
As shown in FIG. 3, the upper bearing wells and lower bearing
wells, when positioned in overlying registration, form a plurality
of bearing chambers 250. The plurality of bearing chambers are
spatially arranged to form the plurality of Braille character cells
210. In particular, each Braille character cell is comprised of an
array of bearing chambers positioned circumferentially about the
rotational axis. For example, as shown, each Braille character cell
can comprise an array of six bearing chambers positioned in a
conventional Braille cell grid having three rows high and two
columns wide. In use, one or more bearings 230, housed within one
or more respective bearing chambers, can be selectively positioned
in a raised or lowered position to display a desired combination of
character dots and thus a desired Braille character.
[0036] As shown for example in FIG. 3, a stationary divider plate
260 is disposed between the lower and upper rotary plates and
separates the bearing chambers into an upper portion 252 and a
lower portion 254. The stationary divider plate also defines a
plurality of pass through apertures 262 configured to selectively
allow communication between the respective upper and lower bearing
wells when a lower bearing well and an upper bearing well are each
rotated into registration with one of the plurality of pass through
apertures 262. In use, the stationary plate enables the plurality
of bearings housed within the bearing chambers to be selectively
positioned in either the upper chamber portion (raised position) or
the lower chamber portion (down position) depending on which
Braille character is to be displayed. Once positioned, a bearing
will then remain in the respective upper or lower portion of a
bearing chamber until the bearing is selectively repositioned in
the opposing portion of a bearing chamber.
[0037] An exemplary stationary plate is also depicted in FIG. 4. As
shown, the stationary divider plate can comprise a plurality of
pass-through apertures 262 defined therein that are sized and
shaped to allow the selective passage of bearing there through.
Thus, by allowing the selective passage of a ball bearing through
an aperture in the stationary divider plate, a ball bearing can
selectively pass from the lower bearing chamber portion to the
opposed upper chamber portion and vice versa through a pass through
aperture defined by the stationary divider plate. In one aspect,
the number of pass through apertures is dependent upon and can
correspond to the number of rows of Braille dots in the Braille
character cell. For example, in an aspect comprising six Braille
dot character cell having array of 3 dots high and two dots wide,
the stationary divider plate can define three pass through
apertures. Alternatively, in an aspect comprising an 8 Braille dot
character cell having 4 dots high and two wide, the stationary
divider plate can define four pass through apertures. As further
shown in FIG. 4, the exemplified three pass through apertures 262
can each be positioned at differing distances D1, D2 and D3 from
the rotational axis. According to this aspect, each distance D1,
D2, and D3 can be selected so that each row of bearing chambers of
the Braille character cell will, when rotated, pass in
communication with a pass through aperture dedicated to that row of
bearing chambers.
[0038] The stationary divider plate can further be configured such
that pass though aperture(s) can be aligned with a means for
selectively positioning a bearing in the upper portion of the
bearing chamber. For example, as will be described in more detail
below, in one embodiment an electromagnet assembly can be used to
selectively position a bearing in the upper portion of a bearing
chamber when the respective upper and lower bearing wells are
aligned in registration with a pass-through aperture. Therefore,
according to this aspect, the pass through aperture(s) of the
stationary divider plate should also be aligned with the
electromagnet.
[0039] In one aspect, it is preferable for the stationary divider
plate to have the thinnest allowable thickness in order to minimize
the distance of travel between the lower position of the ball
bearings and the upper position. The plate should however, be
substantially rigid so that it does not deflect or deform when the
user is reading and pushing down on the character dots. Optionally,
the plate can be non-ferric so that it does not interfere with the
magnetism involved in actuating or pulling a ball bearing upwards
into the raised or actuated position. To this end, in an exemplary
aspect, and not meant to be limiting, the stationary divider plate
can be comprised of a copper plate, which is non-ferric, relatively
stiff and rigid, and can have a relatively thin thickness as
compared to the majority of the plastic or polymeric materials
exhibiting the same characteristics. In addition, a copper plate
can provide a relatively smooth surface which can reduce the
friction of the ball bearings that roll on it. In an exemplary
aspect, the thickness of the copper plate can be approximately 0.02
inches.
[0040] It is contemplated that the apertures can be configured in
any desired shape, such as for example, a substantially circular
hole, or an elongated slot. In the exemplified aspect, the pass
through apertures can be substantially circular having a diameter
selected to be large enough to allow a ball bearing to selectively
pass through the aperture but small enough not to allow adjacent
ball bearings to pass through at the same time. In an exemplary
aspect, the pass through aperture can be approximately 3.26 mm in
diameter.
[0041] The dimensions of the upper and lower rotary plates,
including the diameter of the plates, thickness of the plates, and
the dimensions and spacing of the Braille character cells, will be
dependent in part, upon the number of character cells desired, and
the size of the Braille characters desired. In an exemplified
aspect, these dimensions can be derived directly from the standard
Jumbo American Braille dimensions. Thus, in one aspect, and without
limitation, the cell-to-cell spacing for an exemplified device
comprising 30 character cells can be approximately 8.76 mm.
[0042] Based upon the exemplified cell to cell character spacing
set forth above, the following calculations can then be used to
determine the desired diameter for the upper rotary plate.
Specifically, the reference radius can be taken to be the middle
row of the Braille character cell. As the exemplary distance
between the exemplified cells are 8.76 mm apart, when the cells are
arranged in a circular pattern, the Braille dots in the upper
corners of adjacent Braille character cells become closer together
and the lower ones become further apart from each other. By taking
the middle row of the Braille characters as the reference point,
the difference in Braille character spacing is apportioned.
Accordingly, using equations of the arcs, Equations (I) can be used
to calculate the reference radius.
r = 8.76 ( 360 ) 2 .pi. .theta. [ Equation ( I ) ] ##EQU00001##
Where r is the reference radius,
.theta. = 360 n ##EQU00002##
where n is the number of cells on the disk. An exemplary
illustration of the variables in the Equation (I) is set forth in
FIG. 12. Using the equation (I) above, an exemplary display device
comprising 30 Braille character cells and having a cell separation
of approximately 8.76 mm provides a reference radius of 41.83 mm.
If desired, an added distance cushion can also be added to the
reference radius to provide a cushion for a user to manually rotate
the display assembly. In one aspect, the cushion can be
approximately 20 mm added to the calculated reference radius. It
will also be appreciated that the angular separation between the
character cells in a circumferentially spaced arrangement will
depend on the number of character cells. To that end, the exemplary
aspect comprised of 30 character cells will have a separation angle
of approximately 12.degree.. Using the exemplary procedure set
forth above, one of ordinary skill in the art will be able to
arrive at the desired size of the top rotary disk without requiring
any undue experimentation.
[0043] In one aspect, the lower rotary plates can be sized and
shaped to be at least substantially the same dimension as the top
rotary plate. Additionally, in a further aspect, the lower rotary
plate can also comprise a larger or smaller radius than the top
rotary track plate in order to, for example, accommodate for
additional features of the display device, such as the timing plate
apertures that discussed in detail below.
[0044] The dimensions and the spacing of the upper and lower
bearing wells forming the bearing chambers where the ball bearings
are housed can also be determined according to the Jumbo American
Braille dimensions, as well as taking into account any optional
manufacturing tolerances. For example, the dot base diameter of a
Jumbo American Braille dot is approximately 1.7 mm and the
protrusion height of the dot from the surface is approximately 0.5
mm. As this is the diameter of the actual dot, the well diameter
would therefore need to be slightly larger. Thus, a bearing well
diameter of approximately 2.16 mm can provide a raised dot
resulting in a similar profile to that of the Jumbo American
Braille dot.
[0045] The upper and lower rotary plates can manufactured from any
desired materials, including for example, plastic or acrylic. The
upper and lower rotary plates can also be configured to have any
desired thickness which can, in part depend on the size of a
particular bearing to be housed within a formed bearing well. For
example, in one aspect it is desired for the lower plate to have a
thickness sufficient to form bearing wells capable of housing at
least substantially the entire bearing received therein. Thus,
according to this aspect, the lower rotary plate can have a
thickness at least equal to or greater than the diameter of a
desired bearing. Further, it should also be understood that the
lower plate can further be comprised of a plurality of plates
having thickness which, in combination provide a desired thickness.
Likewise, in one aspect, the thickness of the upper rotary plate is
less than that of a desired bearing diameter so that a bearing in
the raised position and resting on the stationary divider plate
will protrude beyond the surface of the top rotary plate resulting
in a raised bump or pimple forming a dot of the Braille character
cell. To this end, in an exemplary aspect, and without limitation,
the upper rotary plate can be approximately 1/16'' thick and the
lower rotary plate can be approximately 3/32'' thick.
[0046] The refreshable display device of the present invention can
also be configured to provide any desired number of refreshable
Braille character cells. For example, the device can be configured
to comprise from 1 to several hundred Braille character cells,
including for example 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, or
even 200 or more character cells. In still another aspect, and as
exemplified herein, a refreshable Braille display device of the
present invention can comprise 30 Braille character cells.
[0047] Likewise, the number of raised character dots and hence the
number of ball bearings can be dependent upon the number of
character cells in the rotary display assembly. For example, as
stated above a conventional printed Braille character cells
comprise a grid of six dots. Thus, according to this aspect, the
number of ball bearings can be proportional to the number of
character cells by a factor of 6. Accordingly, in the exemplified
aspect comprised of 30 character cells, the rotary display device
further comprises 180 ball bearings.
[0048] The ball bearings can be of any desired size suitable for
providing a raised character dot in a legible Braille character
cell. In one aspect, and as exemplified herein, the ball bearings
are sized and shaped to provide a Braille dot that conforms to the
recognized standards of the Jumbo American Braille dimension,
having for example an approximate raised dot height of 0.5 mm and
an approximately raised dot base radius of 0.85 mm. Accordingly, a
particular ball bearing providing the exemplified raised character
dot parameters exemplified above can be calculated according to the
procedure set forth below. It should be understood that in view of
the exemplary calculation procedure, one of ordinary skill in the
art will be able to determine an appropriate ball bearing based
upon the particular raised character dot parameters desired. In
particular, using the Equation (II) below and solving for the two
unknowns r and .theta. as illustrated in FIG. 13, the diameter of a
ball bearing that will provide the desired raised dot parameters
can be calculated. The 0.5 mm is the exemplary height of the ball
bearing protruding from the upper plate and the 0.85 mm is the
exemplary radius of the Jumbo American Braille dimension for the
diameter.
r sin .theta.=r-0.5 mm
r cos .theta.=0.85 mm [Equation II]
From these calculations, an exemplary ball bearing can have a
diameter of approximately 1.945 mm. To this end, a conventional
commercially available 2 mm diameter ball bearing will have an
insignificant deviation from the calculated diameter and can be
used as an exemplary bearing suitable for use in the present
invention.
[0049] The ball bearings can be comprised of any desired material.
However, in one aspect the bearings are comprised of a metallic
material, such as any conventional ferrous metal, in order to be
magnetically attracted by an electromagnetic actuator discussed in
more detail below. Further, the ball bearing surface should, in one
aspect, be smooth in order to easily roll over the top surface of
the stationary divider mentioned above and discussed in more detail
below. Accordingly, in one aspect, the ball bearings can be
comprised of chrome-plated carbon steel such as the 2 mm
chrome-plated steel ball bearings available from Small Parts, Inc.
of Miami Lakes, Fla., USA (Part No. BS-M02-C). In still another
aspect, the ball bearing can be comprised of a nickel-alloy
combination.
[0050] In still a further aspect, a protective film or sheet 270
can also be applied to the top surface of the upper rotary plate in
order to prevent the ball bearings from coming out of the display.
The protective sheet can be formed of any desired material that is
flexible enough to conform to the spherical contour of a raised
ball bearing and tough enough so that it won't break with excessive
use. To this end, in one aspect the protective film can be a latex
layer. The latex layer can have any desired thickness, including
for example, approximately 0.006'', 0.010'', or even 0.025''. As
will be appreciated upon practicing the present invention, the
latex layer can also provide the added benefit of a soft feel for
enhanced legibility. In addition, the latex layer can also prevent
dirt and other contaminants from passing through the ball bearing
pass through apertures.
[0051] The protective film such as a latex sheet can be attached to
the display or reading surface of the upper rotary plate using any
common craft spray adhesive such as Elmer's spray adhesive and, if
needed, can then be trimmed to the appropriate dimensions. An
exemplary latex sheet can be formed from 0.010'' thick latex sheet
from Small Parts, Inc. (Part No. SLR-010-B).
[0052] The refreshable display device further comprises a means for
selectively positioning the bearings of a character cell array in a
raised or lowered position when communication between the
respective bearing wells is selectively allowed. For example, in
one aspect and as shown in FIG. 5, the means for selectively
positioning a bearing can comprise an electromagnetic actuator
assembly 500 configured to magnetically attract a metallic bearing.
According to this aspect, a bearing housed in a lower bearing
chamber portion (lower bearing well) can be magnetically attracted
by an electromagnet and thus selectively raised into an upper
chamber portion by the electromagnet. Alternatively, a bearing
housed in an upper portion of a bearing chamber can be retained in
a raised position by the electromagnet. Still further, a raised
bearing can be refreshed or repositioned back to a lower bearing
well by allowing the bearing to drop back to a lower portion under
the force of gravity. In use, each bearing can be selectively
positioned in a raised position such that the raised bearing forms
a raised dot on the surface of the rotary display assembly. By
selectively actuating or positioning any desired combination of the
bearings within a Braille character cell into a raised position,
any character of the Braille language can be provided on the
surface of the rotary display.
[0053] The electromagnetic actuator assembly can comprise any
conventional electromagnet or device that produces the same effect
that is capable of lifting a ball bearing by applying a magnetic
field that attracts the ball bearing upwards. In order to provide
the largest lifting power to the ball bearings, the tip of the
electromagnet can, for example, be positioned as close as 1 mm over
the top of the upper rotary plate. The exemplary 1 mm spacing
further accommodates for the exemplary 0.5 mm protrusion of the
ball bearings, leaving an exemplary 0.5 mm safety factor so that
there would be no collision between both surfaces. In one aspect,
the actuators are not put inline to actuate the three row columns
of the characters but rather are staggered around the circumference
of the reader. Thus, in one aspect, the electromagnet of the middle
row of Braille dots can be positioned opposite the reading site and
the left and right electromagnet that actuates the upper and lower
rows of Braille dots can be positioned approximately 60.degree.
apart from each side of the middle electromagnet. This
configuration can allow the desired Braille cell to be completely
displayed before reaching the reading site.
[0054] The electromagnetic actuators should be selected to also
provide a sufficient magnetic activation force capable of drawing
the ball bearing into the actuated position quickly enough before
the next character cell is to be actuated. To this end, the
requisite level of actuation force will depend upon several factors
including the bearing size and weight, the distance a bearing will
travel, the desired rotation speed of a display device, and others
that will be known to one of ordinary skill in the art.
Accordingly, using the exemplified display device of the present
invention as an example, the requisite actuation force can be
calculated as set forth below.
[0055] First, the length that the ball needs to travel, x, is given
by Equation (III):
x=1/2d.sub.l+d.sub.t+t.sub.Cu [Equation (III)]
In the exemplified aspect, d.sub.l is the depth of the lower
bearing well and is equal to 1/8'', d.sub.t is the thickness of the
top bearing well and is equal to 1/16'', and t.sub.Cu is the
thickness of the copper middle track and is equal to about 0.02''.
Accordingly, in the exemplified display device described herein,
the traveling length of the ball bearing from the non-actuated
position to the actuated position is approximately 0.146'', or
3.7084 mm.
[0056] The time allowed for actuation before the actuation of the
next dot can also be calculated as set forth below. In particular,
a very fast or skilled Braille reader can read approximately 120
words per minute. Thus, with an average word length of five
characters, a skilled reader can read up to 600 characters per
minute. Accordingly, to support a fast Braille reading rate of
approximately 600 characters per minute, an exemplified display
comprising 30 characters or Braille cells would have a rotational
speed of approximately 20 rpm (rotations per minute).
[0057] For an exemplary display having a radius to the outer row of
Braille character dots of approximately 44.75 mm, the maximum
possibly velocity of the balls bearings, which occurs at the outer
radius, is given by Equation (IV):
v.sub.max=.omega..sub.maxr.sub.outer [Equation (IV)]
This gives a maximum velocity of approximately 0.0938 m/s. From the
distance traveled and the velocity, the time allowed for actuation
can then be calculated as the quotient of the two. Therefore, the
allowable time for actuation in one aspect as described herein can
be 0.0266875 seconds.
[0058] Given the distance and time traveled, Equation (V) of
one-dimensional kinematics can be applied to determine the
acceleration, a, necessary:
x = a 2 t 2 + v 0 t + x 0 [ Equation ( V ) ] ##EQU00003##
Where v.sub.0 is the initial velocity and is equal to zero and
x.sub.0 is the original height and is also equal to zero.
Simplifying the equation and solving for a gives a minimum
necessary acceleration of approximately 10.4136 m/s.sup.2. This is
equal to the acceleration term in Newton's Second Law of Motion
shown in Equation (VI):
.SIGMA.F=ma [Equation (VI)]
The corresponding free-body diagram of the accelerating ball
bearing is shown in FIG. 14, where F.sub.M is the force exerted by
the electromagnet and mg is the force of gravity. Substituting
these values into Equation (VI), the equation simplifies to
Equation (VII):
F.sub.M-mg=ma [Equation (VII)]
Therefore, in order to obtain the minimum electromagnetic force
required for a successful actuation, the mass of the ball bearing
should be calculated. The ball bearings as exemplified for purposes
of this sample calculation have a diameter of 3/32'', which yields
a volume of 4.3143.times.10.sup.-4 in.sup.3. The density of the
ball bearings used is 0.283 lbs/in.sup.3 (the approximate density
of steel), which yields a mass of 1.221.times.10.sup.-4 lbs, or
5.5498.times.10.sup.-5 kg. Substituting this mass value into
Equation (VII) and solving for F.sub.M yields a minimum
electromagnetic force required of F.sub.M=0.0011 N. Using this
sample calculation, one of ordinary skill in the art will be able
to determine an electromagnet that will supply the requisite
activation force for a refreshable Braille display device
comprising a desired dimension and materials without requiring any
undue experimentation. Following actuation, the character dots can
then be refreshed or dropped to the lowered state by the force of
gravity. To this end, the acceleration due to free-fall is roughly
9.81 m/s.sup.2, which is within the acceptable tolerance of the
exemplary minimum acceleration required of 10.4136 m/s.sup.2 as
calculated above. However, in still another aspect, refreshing the
ball bearings from the top position to the bottom position could be
accomplished using a permanent magnet or an activated
electromagnetic positioned below the pass-through aperture in the
stationary divider plate that would provide a gravity-assist force
to move the ball bearing from the top position to the bottom
position.
[0059] In still another aspect, the refreshable Braille display
device of the present invention can further comprise a means for
timing or regulating the selective actuation or positioning of a
ball bearing. The timing means can be any mechanism or system
capable of selectively triggering the selective actuation or
positioning of a ball bearing. For example, the rotary display
assembly can further comprise a rotary timing plate. The timing
plate can be provided to regulate and ensure a selected set of ball
bearings are selectively positioned at the correct sequence in
time. As shown in FIG. 6, an exemplary timing disk 600 can define a
plurality of timing apertures 610 positioned in the outer
circumference portion of the timing plate disk. As further shown in
FIG. 7 and FIG. 8, the timing apertures 610 can allow light to pass
between a light source 660, such as an LED positioned above the
timing plate, to a light detector 670, such as a photo resistor,
positioned directly below the plate. In use, as the rotary display
is rotated, a timing aperture can pass in alignment with a light
detection assembly 650, comprising the light source and light
sensor. In one aspect, there can be at least one light detection
assembly, comprising a light source and a light detector,
configured to selectively trigger the actuation or positioning of
the bearings. Alternatively, as exemplified herein, there can be a
plurality of light detection assemblies comprising a light source
and light sensor, whereby a single light detection assembly is
dedicated to each electromagnetic actuator and thus one for each
row of dots in the Braille character cell.
[0060] Any light source and light sensor can be used however in the
exemplified aspect, 3 light detectors and relays were bought as a
kit from MPJA (Marlin P. Jones & Assoc., Inc., P.O. Box 530400,
Lake Park, Fla. 33403). To that end, exemplary light sensors that
are suitable for use include those that are included in relay kit
Stock No. 7863-KT commercially available from MPJA. The light
detectors can be mounted flush to the surface upon which the timing
plate rotates into these mounting apertures with, for example, a
conventional epoxy resin adhesive. Likewise, three green LEDs (Cat.
No. 276-1622, from RadioShack, Fort Worth, Tex., USA) can for
example be used to sensitize the light detectors. The three relay
kits can be connected to a power supply with a breadboard from
RadioShack (Experimentor 350 Cat. No. 276-175). In the exemplified
aspect, three power supplies can be used to make the unit
functional. One can be used for the relay/light detector kits, one
can be used to provide power to the electromagnets, and one can be
used to power the light source. Accordingly, FIG. 9 illustrates an
exemplary schematic wiring diagram for the three power supplies. As
shown, the electromagnets can for example receive 5 volts at
approximately 2 amps each, and the light source can be connected in
parallel to two 1.5 volt AA batteries connected in series to
provide 3 volts. Although the exemplified RBD utilizes three
separate power supplies, an alternative aspect can comprise a
single power supply to power all three electrical subsystems of the
display. In one aspect, this power supply/supplies can be
integrated into the RBD itself or be connected to the RBD through a
power cord with an integrated power supply/supplies.
[0061] As light from the LED passes through the aligned timing
aperture defined by the timing disk, the light detector, such as a
photo resistor, can detect and send a signal to a corresponding
relay circuit which switches the connection in the relay and allows
electric current to flow to an electromagnetic actuator. This in
turn enables the electromagnet to generate a magnetic field which
attracts a metallic ball bearing(s) and causes the ball bearing to
be lifted up through the divider plate aperture towards the top of
the display assembly. When the selected ball bearing to be actuated
is positioned in alignment with the pass-through aperture in the
stationary divider plate, the ball bearing will move from the lower
chamber to the upper rotary chamber (or if the ball bearing is
already in the upper rotary chamber, it will simply remain there
when the electromagnet is turned on). As the display continues to
rotate, the ball bearing will move past the pass-through hole in
the divider plate and come to rest on top of the middle stationary
plate, resulting in a raised character dot comparable in size to
regular Jumbo Braille.
[0062] In one aspect, the timing apertures can be aligned
approximately 5.degree. before the corresponding column of ball
bearings, stop in between the two columns of ball bearings in a
Braille character cell, and can begin again and extend, for
example, to a position that is approximately 5.degree. beyond the
second column of ball bearings. As one of skill in the art will
appreciate, this arrangement can ensure that the ball bearing
receives the correct actuation signal and has adequate exposure to
the pass-through apertures in the stationary divider plate to be
correctly actuated per the actuation signal. The timing apertures
can also be configured as slots approximately 1/16'' in width so
that it allows enough light to actuate one specific sensor. In
still another aspect, and as exemplified in FIG. 6b, the timing
apertures can also be configured as slots that are tapered in a
circumferential direction. The circumferential tapering can provide
a diminishing or increasing level of light passing through the
aperture as the plate is rotated in either a clockwise or
counterclockwise direction. The increased or decreased level of
light passing through the timing aperture can be used to determine
which direction the Braille display is being rotated, thereby
allowing a user to read forward or backward in the text being read
on the computer.
[0063] In an exemplary aspect, the timing plate can be connected to
the bottom surface of the lower rotary plate. In addition, the
timing disk can further define a center mounting aperture through
which a fixed support pillar for connecting the stationary divider
plate and stationary divider plate mounts to the display base can
be positioned.
[0064] In an alternative aspect, the timing apertures can be formed
by an appropriately sized and shaped lower rotary plate,
eliminating the need for a separate timing disk. Still further, the
timing disk can in another aspect be primed and/or painted a dark
color, such as for example black. This can ensure that the light
detectors will function properly and will not be confused by rouge
light taking advantage of the transparency of the timing disk
material.
[0065] It is further contemplated in an alternative aspect that the
timing plate can comprise any conventional mechanical mechanism
capable of triggering the selective actuation or positioning of a
ball bearing. For example, a timing plate can be formed having a
plurality of raised pimples positioned in the outer circumference
portion of the timing plate disk. In use, as the rotary display is
rotated, a timing pimple can pass in alignment with a trigger
switch, thus resulting in selective actuation.
[0066] An optional bearing system can also be integrated in to the
exemplified display device. A bearing system may be desired in some
capacity to ensure that the rotating motion of the display would
always be as smooth and continuous as possible. An exemplary
bearing system can be placed between the rotating disks and the
axis about which they rotate. To minimize any increase in the
overall size of the display, the bearing system could, for example,
comprise a relatively flat thrust needle bearing mounted between
the display base and the timing disk to help minimize friction as
the rotary disk is turned by the user.
[0067] The display device can further comprise a base assembly
constructed and arranged to support one or more components of the
display device. As shown in the exploded view of FIG. 10, the
components of the rotary display assembly can be mounted to a
display base assembly 700. In particular, the rotary display
assembly can be mounted to the base assembly by a support pillar
750. In one aspect, the support pillar can be a stationary pillar
to which the stationary divider plate 260 can be connect. Further,
the mounted stationary divider plate can, in this aspect, provide
an axis of rotation about which the movable components of the
rotary display assembly portion of the display can rotate, such as
for example, the upper and lower rotary plates and the timing
plate.
[0068] In one exemplary aspect, three electromagnets 500 (and the
three corresponding LED-light sensor pairs) can be positioned
directly above the top surface of the display along the back
portion of the rotating disk. In particular, electromagnet mounting
brackets 550 can be used to suspend the electromagnets in overlying
registration with their corresponding row of Braille dots. In the
exemplified aspect, the three electromagnets and LED-light sensor
assemblies are further spaced approximately 60.degree. apart from
each other, in order to prevent any interference from the adjacent
electromagnets, and to allow for separate, controlled actuation of
each row of Braille dots.
[0069] A refreshable Braille display device of the present
invention can further comprise a signal controller that interfaces
between the computer text input and the RBD itself to send the
correct signals at the correct time to actuate the individual
Braille dots in order to make the Braille characters corresponding
to the text on the computer. This controller can be a software
package that would translate the written electronic text from Word
documents, Excel spreadsheets, web pages, etc. into binary inputs
that are sent to a control circuit (one for each electromagnet)
that either supplies electricity to the electromagnet (through the
separate relay circuit) or doesn't, depending on whether the signal
is a binary 1 (on) or 0 (off), corresponding to a signal for a
single Braille dot actuation and non-actuation, respectively, or
vice versa. Additionally, because the three electromagnetic
actuators are spaced 60.degree. apart along the back portion of the
display, the binary inputs to the control circuits for the
electromagnets could be staggered and the separate actuation of
each row of the cell timed such that as the user continuously
rotates the display, each individual Braille cell is actuated in
three separate sections of the display (by the three separate
electromagnets, which are timed and activated by the three
LED-light sensor pairs) and then displayed as a complete Braille
cell as the user continues to rotate the cell around to the front
of the display.
[0070] Furthermore, this controller could also monitor the time
elapsed since the last signal was received from the LED-light
sensor combination. After a specific amount of time elapses without
another signal being received from the LED-light sensor combination
(hence, the user is no longer rotating the display), the controller
would automatically shut off any power to the electromagnets to
avoid overheating or any other potentially hazardous situation. The
power would then be restored to the electromagnets when a signal
was again received by the controller from the LED-light sensor
combinations, indicating that the user is again rotating the
display.
[0071] According to this aspect, it would be the responsibility of
the control system to produce the appropriate Braille text and to
respond to user input. The commands the user may wish to send to
the reader can include those which are typical of an electronic
book reader (move forward, move back, bookmark, dictionary and the
like), and commands which are specific to the motion-based Braille
reader of this invention. The latter class of commands may include
start/stop, speed adjustment and repeat (play back of the last few
words to clarify an uncertainty). A display protocol may be
implemented to aid identification of changes in context, as when
the user jumps to a different location in text or looks up a
reference. One example of such a protocol includes a separator (a
brief interval of blank Braille characters, for example) whereby
the user could be informed that the Braille characters following
the blank interval are from a new portion of the text being
read.
[0072] It is contemplated that all of the electronic components in
the display device can be integrated into a display housing such
that the RBD would be one fully-contained unit. The electronic
controller that supplies the necessary input signal from the
computer to the electromagnets could also be integrated into the
RBD display housing. Thus, in one aspect, the display device can
contain all of the subcomponents of the exemplified RBD, and would
only require an interface to the computer it is being used with,
such as a USB cable.
[0073] In use, the rotary display assembly consisting of the
protective latex reading surface, ball bearings, upper rotary
plate, lower rotary plate, and timing disk, can be rotated either
manually or mechanically, i.e., by a motor. As the display rotates,
the user can read the Braille text that is generated in each of the
Braille character cells. While the formed characters are being
read, character cells that have been read are continuously being
refreshed and new characters are being created 180.degree. from the
reading surface of the rotary display assembly.
[0074] Accordingly, in another aspect, the present invention
provides a method for displaying a refreshable Braille character.
The method generally comprises providing a substantially planar
Braille character display assembly of the present invention having
a plurality of bearing chambers have a bearing disposed therein to
form plurality of Braille character cell arrays configured to
rotate about, and in a plane substantially perpendicular to, a
rotary axis. As exemplified herein, at leas one of the plurality of
bearing chambers of the Braille character cell array can be
positioned in registration with a means for selectively positioning
a bearing contained within the chamber. Once positioned, the
bearing in the chamber can be selectively positioning in the upper
portion of the bearing chamber to display a raised Braille
character dot. The raised Braille dot, or the raised bearing, can
then be maintained in the selectively raised position while the
substantially planar Braille character display assembly is rotated
at least one revolution about the rotary axis. These steps can be
repeated until a desired number and pattern of bearings have been
selectively positioned to display a desired Braille character
cell.
[0075] For example, an exemplary sequence of the activation of all
six Braille dots in a single Braille cell according to the present
invention is illustrated schematically in FIGS. 11a-11g. Based on
the geometry of the design, all six dots of a character are not
actuated simultaneously but rather individually. Initially, the
outermost dots are to be actuated, starting with the left-most one.
Next, with these dots actuated, the middle row of dots is to be
actuated, again starting with the left-most one. The innermost dots
are actuated in a similar fashion. Therefore, after the character
cell passes underneath the third electromagnet, all six dots will
have been actuated (or not actuated, depending on the character
being created) and the Braille character is complete. The
refreshing of the character begins when the character first
traverses the first electromagnet after passing by the user.
[0076] As shown in FIG. 11a, a user initially rotates the
refreshable Braille display device reading surface as he/she reads
the Braille text. With reference to FIG. 11b, as the timing
aperture for bearing #1 (B1) reaches the light sensor, light passes
through the timing aperture and a signal is sent from the light
sensor to the signal controller. If the signal controller has
received a signal to actuate this particular Braille dot, this
turns on the electromagnet above B1, and causes the B1 ball bearing
to be lifted up into the top position. In FIG. 11c, as the user
continues to rotate the display, B1 will remain in the top
position. Just as in FIG. 11b, as the timing aperture for bearing
B2 reaches the light sensor, a signal is sent from the light sensor
to the signal controller. If the signal controller has received a
signal to actuate this particular Braille dot, this turns on the
electromagnet above bearing B2. Just as before, this causes bearing
B2 to be lifted up into the raised position. As the user continues
to rotate the display, bearing B2 will also remain in the raised
position. As the user continues to read and rotate the display, the
Braille cell containing bearing B1 and B2 reaches the next light
sensor-electromagnet actuator combination. In FIG. 11d, as light
passes through the timing aperture for bearing B3, B3 is actuated
or positioned into the raised position just as B1 and B2 were, and
will remain in the top position as the user continues to rotate the
display. As the user continues to rotate the display, B4 will be
the next bearing actuated in the same manner as bearing B1, B2, and
B3, and will remain in the raised position as the user continues to
rotate the display. As the user further continues to read and
rotate the display, the Braille cell containing bearings B1, B2,
B3, and B4 reaches the next light sensor-electromagnet actuator
combination. As light passes through the timing aperture for
bearing B5, bearing B5 is actuated into the raised position just as
bearings B1, B2, B3, and B4 were and will remain in the upper
raised position as the user continues to rotate the display. Still
further, as the user continues to rotate the display, bearing B6
will be actuated in the same manner as B1, B2, B3, B4, and B5, and
will remain in the top position as the user continues to rotate the
display. Now all of the six dots in this particular Braille cell
are actuated, and as the user continues to rotate the display
around, the newly actuated cell will reach the reading position, as
depicted above. In the exemplified aspect, it is contemplated that
there are 30 Braille cells positioned around the circumference of
the display. Thus, as the user continues to read the Braille
characters, he/she will rotate the display to bring the next
Braille character into the reading position. This rotation is what
causes the actuation that has just been described.
[0077] Lastly, it should be understood that while the present
invention has been described in detail with respect to certain
illustrative and specific aspects thereof, it should not be
considered limited to such, as numerous modifications are possible
without departing from the broad spirit and scope of the present
invention as defined in the appended claims.
* * * * *