Note: Descriptions are shown in the official language in which they were submitted.
WO 94~1127~ PCI/US93/11003
.`21 ..4.8:~ 5 ~
.,
,", ~ .
INDICATOR CAP HAVING SELECTABLE DOSAGE SCE~EDULE / ~`
,'.,,:
BACKGROUND OF THE INVENTION
The present invention r~lates ~o closure :
members for containers, bottles and the like and, more ~-~
particularly, to closure members having indicator means `:~
to indicate the number of times the container has been
opened. The inventlon can also be used for any other
application in which the number of tim~s a given
15 activity is performed must be indicated.
In the medical field, medical drugs have a ` ~
predetermined therapeutic range in which the.effects of .`
taking the drug are beneficial. Under-utilization of a
drug may endanger the user with the drug's side effects
without reaching levels necessary for a therapeutic
action. On the other hand, over-utilization may cause
side effects or toxicity to a much greater extent than
any possible benefit. Thus it is~critically importank
that a patient foilow prescribed directions on
medications, yet frequently patients forget whether ``
they have taken medication and either omit do~es or ~ ;-
repeat them. ~;
A considerable number of pill-timing schemes `~:
have been used to solve the problem of reminding a
patient to take a dose of medicine or reminding him .-:
that he has already taken the dose. The most common ? '; `
ones involve some scheme of compartmentalization of the
necessary medication, such that the pills are placed in
compartments that are labeled by day, dose number or
time of day, or~that are serially numbered. These `
WO94~11272 PCT/US9~/11003 ~-
2 ~ 2-
I ........
devices are reasonably satisfactory i~ a responsible
person is available and has the time and patience to
fill the compartments properly. -
In dispensing pills of a single type, a number ' ~
of bottle caps have been invented having a window -
through which an index symbol is visible. In only a
few devices does the indicating element index in -
position relative to the window each time the cap is
loosened, removed, replaced, and re-tightened. Thus, -
by looking at the index mark displayed through the ~-
window, a user can see where in repetitive sequence of
dose he or she is.
A drawback to the window arrangements in the
prior art is that they are usable only with a single ;~
}5 dosing regimen. For example, a window which displays
consecutively "M, Tu, W, Th, F, Sa, Su" is usable only ;~
with medicine that is to be taken once a day. If it is
used with medicine that is to be taken twice a day, the
symbols visible through the window will not match the ~;~
actual day and the device will confuse more than assist
the user. Conversely, a window which displays
consecutively "Ml, M2, Tul, Tu2, Wl, W2, Thl, Th2, Fl,
F2, Sal, Sa2, Sul, Su2" for medicine that is to be
taken tw.ice a day, will not be usable with medicine
that is to be taken once a day. Of course, it is -
possible to use a set of symbols that are simply
numerical integers such as "l, 2, 3, 4, . . ." rather
than s~mbols that include abbreviations for days of the
week, hut then the device is much less useful because
it requires the user to keep count of where he is in -
the sequence
One of the most serious d.isadvantages of prior
art devices of the window indexing type is that there
is no warning to the user in case the user does not
turn the device far enough during the opening or
closing ts proper1y advance t~le window. Unless the
~
W~94/11~72 PCT/US93/11003 ~ ``
3~
':'',
user is alert to the index value before opening and I -
then after closing such devices, the user will be , ~`
unaware that the window failed to advance to a new :~
index. Most users, especially the elderly who may not . ;~
understand how the device operates, will not be this ` ~;
alert to the functioning of the device. In addition,
most prior art devices fail to provide positive locking
in both directions of movement; thus, the index may be
moved appropriately when the device is opened or
closed, but additional movement is not prevented when ~-
the device is moved in the opposite direction. This ~-
allows the index to drift, often causing failure or an ~`
incorrect reading, particularly after the device has
been used over a period of time.
The device of U.S. Patent 4,011,829 issued
March 15, 1977 to Wachsmann, et al., attempts to i
provide positive locking in both directions, but
because of the direction of the tooth designed to
prevent movement of the index upon closure, the device
may not work reLiably, particularly after wearing with
use. Also, the device of Wachsmann does not provide
space for the ratchet teeth to slide past the
engagement teeth when the device is moving in a -~
direction wherein such teeth should disengage, which
may cause unreliable operation over a period of time.
Another drawback of this device is its inclusion of a
complicat~d "child proofing" feature with the indexing
feature, which makes the device quite compl.ex. Cther
features of this de-vice, such as the method of
pro~iding the lost motion drive and the requirement of
a post in the middle of the elements to hold the device
together, also increase its complexity.
The device of U.S. Patent 3,151,599 issued
Octob~r 6, 1964 to Livingston provides positive loc~ing
in both directions, but it does so by means of very
closely spaced projections that would be difficult to
W094/1127~ PCT/US93/11003
manufacture economically. Furthermore, this device l `
does not provide space for the projections to move ¦ -
while sliding past each other when not engaged.
The device of U.S Patent 4,666,051 issued May
19, 1987 to Trick has an indicator wheel with a
serr~ted rim projecting above and below the plane of
the wheel. The serrations engage mating serrations in
upper and lower elements in order to drive the
indicator mechanism. The serrations are rigid and,
therefore, tend to wear excessively as they slide past
one another.
The device of European Patent Application Mo. -
87100917.2, published July 27, 1987, by Schwab, has a
cup-shaped exterior element that engages a ~
frustoconical closure cap. The Schw~b device is ~ :
somewhat complicated in design and manufacture. The
device of U.S. Patent 4,220,247 issued September 2,
1980 to Kramer also includes a cup-shaped exterior
element which engages an inner eLement. It appears `~;
that Wachsmann, Livingston, Trick and Schwab all
utilize an ordinary symbol arxangement which is usable , -
only with a single dosing regimen.
Other devices in the art include U.S. Patents
4,511,050 by Nicol; 4,365,722 by Kramer; 4,749,093 by
Trick; 4,782,g66 by Thackrey; 4,753,189 by Mastman;
4,705,182 by Newel-Lewis; 4,662,520 by Griffen;
4,641,759 by Kelley; 4,634,012 by Kelley; 4,562,933 by j ~ `
Dennis; 4,528,933 by Allen; 4,511,050 by Nicol; i ~
4,548,157 by Hevoyan; 4,501,370 by Kelley; 4,489,834 by ~ -
Thackrey; 4,432,300 by Lyss; 4,419,016 by Zoltan; ~-
4,405,045 by Villa-Real; 4,357,192 by Moser; 4,347,804 ~
by Villa-Real; 4,094,408 by Ford; 3,936,879 by Walton; ~: ;
3,960,713 by Carey; 3,926,326 by Grau; 3,921,568 by ¦;~
Fish; 3,887,099 by Gillman; 3,753,417 by Garby;
3,446,179 by Bender; 3,334,731 by Dale; 2,943,730 by .
.~
': .
'''~.
WO94/11272 ~11`3'~5~ PCT/US93/11003 ~ ~
-5-
Tregilgas; 2,939,597 by Greene; 2,587,147 by Guion; and
498,8Sl by Adsit. 1 -
It is thus apparent from a review of this art
that there is a need for an improved indicator cap in
the manner of the present invention that allows an
indicator device to be used on a medicine container for
use with more than a single dosing regimen.
Preferably, the dosing regimen to be indicated by ~he
device could be chosen simply and effectively at the
time the device is to be u~ed. Additionally, there is
a need for an indicator cap that provides positive
controlled movement of the index on both opening and
closing of the device, while also providing an
indication to the user that the index has functioned
properly each t.ime the device is used. Preferably, the
basic design of such a device can also be used in other
applications where it is necessary to have a record of
the number of times a given event occurs. Also, it
would be desirable for such a device to include the ;
option of not utilizing the indicator system at all if
that is the desire of the user. i~
It is also apparent from a review of this art i~`
that there is a need for an improved indicator cap that ;~-
can be used as a child-resistant closure. Preferably,
such a cap would have a minimum of parts, would be
easily manufactured and assembled using standard
injection molding and assembly methods, and could be
used with ordinary containers that are not necessarily
specially designed for the cap.
.
SUk~RY OF THE_INVENTION
It is an object of the present invention to
provide an indicator device to indicate the number of 7
times a given event has occurred. Such an invention
may have applicability in the control of chemical
containers, the development of photographic film and
'''.-~
WO94/11~72 PCT/US9~11003 ~~
~ .
many other areas. More particularly, it is an object
of the present ir.vention to provide an indicator cap , ~;
for a medication dispen~ing bottle or the like that , ~-
provides an indication each time the bottle is opened '
and then reclosed.
It is a further object of the present invention
to provide an indicator device for use with more than
one medicine dosing regimen. Another objection of the
invention is to provide a device where the choice of ,-~
dosing regimens can be made simply and effectively by
the user at the time the device is put into use, rather
than at a manufacturing facility beforehand.
Another object of this invention is to provide
an indicator device in which the indicator system can
either be operated or not operated by the user. ~-~
It is another object of this invention to
provide a device that has positive control of the index -~
member during both the opening and the closing motions 1~ -
and to require the advancement o~ the index member by
one and only one new index during each complete opening
and closing cycle. ~
Yet another object of the invention is to , -
provide an audible sound to confirm that the device has
been rotated sufficiently to move the index to the next
location and to also provide an audible sound when the
device has been rotated sufficiently to r~-cock the
device for the next open-close sequence.
Still another object is to provide space within
the device f~r the locking mechanisms to slide past
each other when not engaged to allow such mechanisms to
work reliably over Q long period of time.
Another object of the preserlt invention is to
combine functions usually requlring several components ~
in~o single components to reduce t~,e complexity of the . ~-
device and pravide ease of manufacturability and 1 --
,~.:,`'''
','""'`',.
W~94/~1~72 ,~ 2 t~ PCT/VS93/11003 ~ ~
: ; 7 L```~ `
assembly using standard injection molding and assembly
techniques.
Another object of the present invention is ~o
provide an indicator assembly that can easily be fitted
to an ordinary container without requiring any special
modifications to the container itself.
Another object is to provide a device with
indi.cator symbols that can be sensed by touch such as ;
raised letters or braille. ;~
Another object is to provide a device that can
be easily grasped by elderly or impaired patients, as ~;
by including grasp-faci.litating elements on the device. l``-
Another object is to provide a device which is
easily manufactured and assembled with a minimum of --~
parts. `
BRIEF DESCRIPTION_OF THE DRAWINGS
FIG. l is a perspective view of a medicine
container with an indicator device of the present
invention.
FIG. 2 is a plan view of an indicator wheel
with a set of indicator symbols according to the
present invention.
FIG. 3 is a plan view of the outer cover with a :~
window and a set of window covers according to the
present invention.
FTG. 4 is a detail of the window and window
covers of the present invention.
! FIG. 5 is a sectional view taken along line 5-5
of FIG~ 4.
FIG. 6 is a sectional view taken along line 6-6
of FIG. 4. i ~-
FIG. 7 is a detail of the window and window
covers showing certain labelling in the present
invention. ,
WO94/1127~ PCT/US93/]1003 C;~ ~
~ ~3 ~ 8- ~ ~
FIG. 8 is a perspective view of an alternative
embodiment of the invention.
FIG. 8A is a sectional view taken along line
8A-8A of FIG. 8.
FIG. 9 is a perspective view of a further
alternatlve embodiment of the invention.
FIG. 9A is a sectional view taken along line
9A-9A of FIG. 9.
FIG. lO is a perspective view of a ~urther
alternative embodiment of the invention.
FIG. lOA is a sectional view taken along line
lOA-lOA of FIG. lO.
''~
DETAILED DESCR _TION OF THE INVENTION
A pictorial view of a medicine bottle 12 with
an indicator cap 14 is shown in FIG. l. Such devices
in general are known in the art and are not described -
in detail here. In particular, such a device is
described in detail in U.S~ Patent No. 5,009,388 by
Barker of which the present invention is a ~ `
continuation-in-part, and in U.S. Patent No. 4,0ll,829
by Wachsmann. Briefly, the medicine bottle 12 is of -
the ordinary plastic type for holding a number of ;~
medicinal pills or tablets. The neck of the bottle is
threaded to receive the threaded indicator cap 14. The ~-
indicator cap in the preferred embodiment includes an
outer cap with a window 16 therethrough, an inner -
retainer and an indicator wheel disposed between the
outer cover and inner retainer having a set of
indicator symbols selectively visible t~.rough the ~-~
window 16. A pawl on one of the indicator wheel and ~`
the inside surface of the outer cover and a set of --
engaging teeth on the other of the indicator wheel and ` -
the inside surface of the outer cover allow rotation of
the outer cover relative to the indicator wheel in a
first rotational dlrection but not in a second
: ,~
.~:
WO94/11272 PCT/US93/11003 -;~
21ll~32~ ~`',-`
_ g ~
rotational dlrection opposite the first rotational
direction. A pawl on one of the indicator wheel and
the inner retainer and a set of engaging teeth on the I ~
other of the indicator wheel and the inner retainer ~ ;;`
allow rotation of the indicator wheel in the second
rotational direction but not in the first rotational -~
direction. ~;-;
"Lost motion is provided between thè outer
cover and the inner retainer by a set of `
circumferential tabs on one of those members and
circumferential engaging grooves on`the other of those --~
members. The tabs have a shorter circumferential -~
length than the grooves, so that the outer cover has a -`~
limited range of rotational motion relative to the
i5 inner retainer.
The effect of this configuration is that -~
rotating the outer cover in the first direction (such ~-
as clockwise) causes it to rotate while the indicator
wheel and inner retainer remain stationary, thereby
advancing the window in the outer cover to the next
indicator symhol on the indicator wheel. This also
causes an advancement of the pawl past another tooth of
the teeth and pawl on the outer cover and indicator i
wheel, thereby producing an audible "click" to confirm
proper operation to the user. When the limited range -~
of rotational motion between the outer cap and the ~`
inner retainer is exhausted by the tabs reaching a
circumferential end of the grooves, the inner retainer
begins rotating with the outer cover. Because the
retainer directly or indirectly includes the threads
which engage the threaded neck of the ~ottle, ~he
device is thereby screwed onto the bottle to close and ~-
seal the bottle. When the outer cover is then rota~ed
in the opposite direction (such as counterclockwise)~
the outer cover together with the indicator device
rotate relative to the inner retainer through the
WO94/11272 PCT/US9~/11003
,"~" ~ ~ .
!3 æ ~ 10-- ,
limited range of motion available from the tabs and
grooves, while the inner retainer stays stationary.
This causes an advancement of the tooth past another
pawl in the teelh and pawl on the indicator wheel and ,~
inner retainer to produce another audible "click" to '
confirm the proper operation of the device to the user.
When the limited range of rotational motion between the
outer cover and inner retainer is exhausted by the tabs '~
reaching the opposite circumferential end of the
grooves, the inner retainer begins rotating with the
outer cover to unscrew the device from the bottle and
access the contents. `
It will be apparent that a number of other
variations are possible on this lost motion system. In -
particular, the lost motion indicator device using the
window dascribed herein may be used in combination with ;
a child-resistant mechanism which re.sists the removal
of the closure from the bottle by a child. Common
child-resistant mechanisms include the "push and turn" -
type which require the application of an axial force
urging the closure toward the container simultaneous
with the rotation of the closure. The axial force may - -
cause the engagement of lugs and notches that are ~`
p~sitioned on the closure and the indicator device in
the manner of parent application no. 07/718,354 filed
June 21, 1991, or may disengage a set of lugs and , -~
bayonet grooves on the closure and the container neck
in the case of a closure and container that use that ! ~-
type of closing mechanism rather than threads.
The aspect of the indicator cap 12 to which the
present invention is particularly pertinent concerns ' ~:
the window 16 for the display of indicator symbols on
the indicator wheel. The indicator whael 30 having a ~ ;
set of indicator symbols 32 is shown in FIG. 2; a top
plan view of the outer cover 14 showing the window 16
is shown in FIG. 3; details of the window 16 are shown
....
'`:
.
~V~94/l1272 PC~/US93/11003 l~
214~2a~ ~
f
in FIGs. 5-6; and the combination of the indicator
wheel 30 and the overlying outer cover 14 with window
16 to display the indicator symbols 32 on the indicator
wheel 30, is shown in FIG. 4. `
The indicator wheel 30 (see FIG. 2) in the :~
preferred embodiment is a circular disk-shaped element ;
having a diameter allowing it to rest within the outer :
cover 16 (from FIG. 1) and a thickness sufficient to
impart some rigidity to the disk. An indicator wheel
1~ 3Q in a commonly sized indicator device might have a
diameter on the order of an inch and a thickness of a
sixteenth to an eight of an inch. The indicator wheel
30 will also generally include a means to engage the
outer cover 16 such as a pawl on its upper or
circumferential surface (not shown) to engage mating
teeth on the inside surface of the outer cover as
mentioned above. -
The indicator wheel 30 has printed onto the top
surface a set of indicator symbols In the embodiment .
shown in FIG. 2, the symboIs include an inner set 34 `
and an outer set 36 in which the inner set 34 is
positioned radially inward from the outer set 36. Both
sets of symbols 34 and 36 fit within the window 16.
The outer set of symbols 36 is a set of abbreviations
for consecutive days of two weeks, namely "M, Tu, W,
Th, Fr Sa, Su, M, Tu, W, Th, F, Sa, Su". These
fourteen symbols correspond to fourteen teeth on the
teeth that mate with the pawl on the indicator wheel 30
and outer cover 14) so that each click of the pawl past
a tooth positions one new symbol in the window 16.
Like the outer set of symbols 36, the inner set of
symbols 34 is a set of fourteen abbreviations for ~.
consecutivs days of the week. However, the outer
symbo's 36 include two numbers for each day, as in "M1,
M2, Tul, Tu2, W1, W2, Thl, Th2, F1, F2, Sal, Sa2, Sul,
Su2". The formatting of the symbols shown in FIG. 2 ~ ;
. .
WO9~1272 PCT/US~3/11003
~r~ 12- 1:~
positions the numeral below the day abbreviation for
the inner set of symbols 36. '
It can be appreciated that the outer symbols 36
can be used when the device is to remind the user to
take one dose a day. In that event, each time the
device is removed from and replaced onto the container
to obtain a dose of medication, the outer symbols 36
will advance one position to a new day. The user
thereby is alerted whether he has taken his medication
that day or not. Similarly, the inner symbols 34 can ~-
be used to remind the user to take two doses a day. In
that event, each time ~he device is removed from and
replaced onto the container to obtain a dose of
medication, the inner symbols will advance one
position. Because each day includes a "l position and
a l'2 position, the user is thereby alerted to take two
doses a day.
Other sets of symbols could also be used
depending on the dosage schedule desired. For example,
it will be readily apparent that a set of symbols could
be used including every other day such as "M, W, F". .
. for medicine to be administered every other day, and -~
a set of symbols could be used including three numerals --~
for each day such as "Ml, M2, M3, Tul, Tu2, Tu3' . . .......... - `-It is also possible to include more than two sets of
symbols, such as three, four or more sets. Each set
would have an appropriate window cover in the manner
described below, so that the user could choose the --
appropriate set depending on the dqsired dosage ;
schedule~
The outer cover 14 is shown in a top plan view ~-
in FIG. 3. That view also shows the window 16 through
the outer cover l4, and the inner window cover 20 and t `,
outer window cover 22. The inner window cover 20 - -
covers the radially inner portion of the window 16
whlle the outer window cover 22 covers the radially
W~94/11272 ~ S~ PCT/US93/11003
-13-
outer portion of the window l6. The inner window 20 ¦
and outer window 22 are joined to the boundary of the
window 16 by tabs 24 and 25 for the inner window co~er 1.
20, and tabs 26 and 27 for the outer window cover 22.
The tabs 24, 25, 26 and 27 are shown best in FIGs. 4
and 5. They are essentially narrow tabs that extend
from the window covers 20 and 22 to the boundary of the
window 16. The tabs 24, 25, 26 and 27 may be
approximately the same thickness as the window covers
20 and 22, or may be thinned in comparison to the
window covers 20 and 22 in the manner shown in FIG. 6. - ::
The inner window cover 20 fits within the radially
inner portion of the window l6 and therefore has a ~-
slightly smaIler perimeter than the boundaries of that
portion of the window. Similarly, the outer window
cover 22 fits within the radially outer portion of the
window and therefore has a slightly smaller perimeter
than that portion of the window. The dimension of the
inner window 2~ in the radial direction is sufficient
to cover the inner set of symbols 34 on the indicator
wheel 30 while the dimension of the outer window 22 in
the radial direction is sufficient to cover the outer -, ~;
set o.symbols 36 on the indicator wheel 30.
The external surface of each window cover 20
and 22 may include printed labels to indicat~ which
portion of the window is to be used for a desired
dosing schedule. Such instructions can be on the outer ~ :
cover 14 or on the window covers 20 and 22 as shown in
FIG. 7. The inner window cover 24 has a label statinq
"l Tim~ A Day" with an arrow pointing to a tab 26
attaching the outer window cover 22 to the outer cover ~- .
14. If the device is desired for use with medicine to ~ -
be taken once a day, the user knows from this label to
break tab 26 (and then tab 27) to remove the outer
window cover 22 and expose the twice a day outer `
symbols 36 on the indicator wheel 30. The removal of -~
'
WO 94/11272 PCr/US9a/11003
3~ i5
the outer window cover 22 also effects a removal of the ,
labelling on the outer window cover, leaving only the
labelling on the inner window cover 20. Thus, the user
is left with a device for once a day dosing that is i `~
labelled as such. Similarly, if the device is for use
with twice a day dosing, the user is instructed by the
label "2 Times A Day" and the accompanying arrow to `
break tab 25 (and tab 24) attaching the inner window
cover 29 to the outer cover 14 to remove the inner
window cover 20 and expose the twice a day symbols of ~
the inner symbols 34 on the indicator wheel 30. The `
removal of the inner window cover 2~ also effects a ~-
.
removal of the labelling on the inner window cover 20.
Thus, the user is left with a device for twice a day
dosing that is labelled as such.
The chosen window cover 20 or 22 is removed ;~
from the window 16 by the user breaking at least one of
the tabs 24, 25 26 or 27 and pulling the window cover
20 or 22 away from the window 16. The breaking of the
~0 tabs 24, 25, 26 or 27 may be assisted by the use of a
pencil, toothpick, knife, fingernail or other somewhat -~
sharp object which can be used to press the window
cover 20 or 22 downward to shear the tabs 24, 25, 26 or
27, or which can be used to insert in a slot between
the window cover 20 or 22 and the boundary of the
window 16 to pry the window cover 20 or 22 away from -
the outer cover 14.
The outer cover 14 and window covers 20 and 22
are injection-moldable plastic in the preferred
embodiment, but it will be apparent that other
materials may be used. The means for attaching the
window covers 20 and 22 to the outer cover 14 is
described as the tabs 24, 25, 26 and 27, which are
preferably injection-moldable plastic that is formed
with the forming of the outer cover 14, but any other
attachment means is satisfactory provided it allows the
. .
,.
WO94/ll272 2 ~ ~ 8 2 ~ ~ Pcr/us93/1]()03
,,......................................................................... ...
. -15- ..
I
window covers 20 and 22 to be removed from obstructing
the window 16. For example, the window covers could be
paper or plastic sheets whicn are simply adhered to~the
boundaries of the window 16. They could also be part
of a larger paper or plastic sheet ~Thich covers part or ~;
all of the type of the outer cover 14, and is separable
from that larger sheet by scored lines or tearable ::~
folds.
Alternative embodiments of the.invention are :.
shown in FIGs. 8-10 which depict some of the variations
mentioned above. FIG. 8 shows a perspective view of
the outer cover 14 with the widow 16 therethrough,
along with an inner window cover 120 and outer window
cover 122. The inner window cover 120 is attached to
the outer cover 14 by a tab 124 similar to the tab 24 ~:~
that attaches the inner:window cover 20 to the outer ;~.
cover 14 in the embodiment described above and shown in
FIGs. 2-7 However, in the embodiment of FIG. 8, the
tab 124 connects the inner window cover 120 to the .
outer cover 14 at the radially inner boundary of the
window 16 rather than at one of the sides of the window
16 as in the embodiment of FIGs. 2-7~ In addition, the -~
inner window cover 120 has an upstanding lip 121 at its `.~
radially outer edge. The purpose of the inner window ..... :
cover lip 121 is to provide something for a user to
grasp in order to pull the inner window cover 120 from ` .
the window 16. Similarly, the outer window cover 122
is attached to the outer cover 16 by a tab 126 at the
radially outer boundary of the windo;w 16 rather than at ~-
the sides of the window 16, and the outer window 122 ~.
has its own upstanding lip 123 so that the user can
grasp a~d remove the outer cover 122. Thsrefore, this ,
em~odiment would not require any tool such as a pencil s .~-~
to punch the window covers 120 and 122 from the window
16.
.~ '...
W~4~1272 PCT/US93/11003 ~ ~
~ :.
The embodiment shown in FIG. 9 utilizes an
inner window cover 220 and outer window cover 222 which `
slide to open the window 16. The inner window cover '
2~0 is fitted into a slot 221 which extends into the , ~
thickness of the top of the outer cover 14 as better ~-
shown in the cross-sectional view of FIG. 9A taken
along line 9A-9A of FIG. 9. One side of the inner
window cover 222 has an upstanding edge 235 which
allows the user to easily slide open the inner window
cover 220. Similarly, the outer window cover 222
slides through an outer window cover slot 223 in the
thickness of the top of the outer cover 14 (which may
be undivided from the inner window cover slot 221 as
shown in FIG. 9) and has an upstanding edge 237. The
user operates this embodiment by selecting the window
cover 220 or 222 to be opened, and then opens it by
sliding it into its respective slot 221 or 223 using
the upstanding edge 235 or 237. This embodiment has
the notable advantage that the user's selection of a
window cover to be opened is reversible; the user can
simply close an opened window cover by sliding the
window cover back over the window and then open the ~-
other window cover instead.
The embodiment shown in FIG. 10 includes a ;~
paper or plastic sheet for the inner window cover 320 ;
and another paper or plastic sheet for the outer window -
cover 322. F.ach window cover 320 and 322 is adhered to
the outer cover 14 in the region surrounding the window ~ -
16 by an adhesive on the side of the sheet facing the ~ `
outer cover 14. Each of the window covers 320 and 322 ~ ~-
is wider in the circumferential direction than the
window 16, so that it overlaps the outer cover 14,
thereby presenting an overlapping surface for J
application of the adhesive. The window covers 320 and
322 may include ends 321 and 323 which are not adhered
to the outer cover 14, so that they stand apart from
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WV94~1~272 214 8 2 a 4 PCT/US93/11003
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the outer cover 14 to be grasped by the user, as better
shown in FIG. lOA. To operate this embodiment, the
user selects the window cover 320 or 322 to be remov~d,
and then removes it by grasping the unadhered portion 1 .
321 or 323 and peeling the window cover 230 or 3~2 off
the outer cover 14 to expose the desired portion of the
window l6.
It will also be apparent that, although the
preferred embodiment described above uses a single
window with two coverings for concentric circles of
indicator symbols, the device could instead use more
than one window each with its own cover to cover the
respective sets of indicator symbols. In such a .
configuration, the indicator s~nbol sets need not be -
concentric circles but could be located anywhere on the :~
device. It will also be apparent that the window ~.
covers 20 and 22 of FIG. 7 could be hingedly attached
to the outer cover l4 by breaking away only one of the ... :
two tabs that attach each of them to the ou~er cover so `~:
that the remaining tab acts as a hinge. Alternatively,
a so called living hinge could extend along one side of
the window cover to allow hinged opening. ; ;
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