Note: Descriptions are shown in the official language in which they were submitted.
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- BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to the manufacture o~ tablets,
and more particularly to the manufacture of tablets to be
sealed in pouches defined by paired sheet materials.
Description of the Prior Art:
Most tablets, whether for medicinal purposes or otherwise,
are manufactured with essentially the same basic shape of
essentially flat broad surfaces. In many instances, such
as when the tablets contain some active chemical agent,
they are desirably vacuum sealed withîn sheet-like
- packaging ;n sandwich relationship, in such manner that
the sheets converge to form a pouch about the tablet defin-
ing a perimeter generally corresponding to a circle.
Conventional tablet shape is defined in cross-section by
essentially flat, parallel broad surfaces, sometimes
defining at the circumferential periphery a slight bevel,
that has been provided primarily to minimize tablet edge
fracture.
20 The high cost of raw materials9 including packaging
materials has prompted consideration of ways to reduce
incidental costs to keep down the ultimate cost of the
tablet product. Consideration has therefore recently been
- given to a reduction ;n the packaging material requirements
for tablets, and a review of the prior art tablet discloses
a substantial amount of unused space in the package pouch.
In particular, the unused space or wastage is most apparent
when the tablet is of increased thickness, the latter to
assure sufficient tablet strength during manufacture and
shipping. Also, in the instance where the tablet is of
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increased ~hickness and is packaged by sealing within pouches
formed by parallel sheet materials, the conventional tablet
configuration has been found to.exert a strain on the pack-
age that causes ~he seals between the package sheets to rup-
ture~ with the result that product shelf life is reduced andspoilage may occur.
Another problem that has existed concerns the packaging of
the tablets. Generally, tablét packaging is performed by
the adhesive bonding of parallel sheets of packaging ma-
terial, with non-bonded areas defined periodically on the
sheets to provide pouches to retain the tablets. The tablets
are usually conveyed while resting on their broad surfaces,
and reach a chute, where the tablets drop vertically down-
ward and are then canveyed between the package sheets as
1~ they are brought together to seal off the pouch area.
During the foregoing procedure, the tablets occasionally tend
to stack or ride upon each other in the course of the verti-
cal drop into position between the package sheets. This
occurrence, known as "shimming" is undesirable and can cause
jamming of the packaging machinery, so that the machinery
must be shut down to remove the extra tabTets from the
pouch. Naturally, such difficulties are time consuming and
add to manufacturing expense.
It therefore exists to correct the difficulties recognized
in the prior art, to provide a tablet that reduces packaging
costs, by reducing both the s;ze and thickness of the packag-
ing materials, as well as a reduction in the inc;dence of
package failure. Also, it would be desirable to prepare a
tablet that reduces or eliminates the occurrence of "shimming"
during packaging.
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SUMMARY OF TIIE INVENTION
In accordance with -the presen-t invention, a
-table-t having an improved conf:igura-tion for more economical
sealable packaging and reduced spoilacJe, comprises paired
broad outer surfaces generally opposed to each other and
terminating in substantially parallel, spaced apart
surface perimeters, at least one of -the surfaces extending
convexly away from the other and defining a central convex
section, and a perime-trically adjacent peripheral convex
section. A continuous rim extends transversely between
the surface perimeters and preferably defines a cylinder~
In a preferred embodiment, both broad outer surfaces extend
convexly and cooperate -to define a bi-convex configuration.
The table-t of the present invention preferably
comprises paired broad outer surfaces that ex-tend convexly
away from each other, with each outer surface ha~ing
respective convex sections defining exterior sur~aces dis-
posed a-t an angle of at least, and preferably cJreater than,
180 wi-th respect to each o-ther. A continuous ridge is
preferably defined on the exterior of the broad outer
surfaces at the junction of the central and peripheral convex
section, and this outer edge defines the tablet point bend,
i.e. the point at which the walls of the pouch containing
the tablet are drawn toward adhesive contact with each
other. Preferably, the walls and the outer surfaces of the
peripheral convex sec-tions subtend between them an acute
angle, which more preferably may be less than ~5.
The inven-tion also relates to a sealably packaged
tablet which comprises, in combination, an essen-tially
planar -tablet package prepared from opposed packacJe sheets
peripherally adhered to each other ancl defining periodic:~lly
between them, centrally disposed, air-tight tablet pouches
containing the -tablets of the invention as described
above. The present
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packaged tablet utilizes a pouch that is reduced in size
while retaining the capability for holding a tablet havin~
equivalent weight and content to ~hose of the prior art.
The invention also includes a method for preparing an im-
5 proved tablet, comprising compressing the material to be
prepared in tablet form within a tablet die defining broad
outer surfaces of which at least one and preferably two are
concave in configuration, and thereby adapted to form a tablet
~ having broad outer surf3;ces of convex shape. Preferably, both
10 1~ broad surfaces of the ~ are concave, and a tablet having
bi-convex configuration is formed~ Furthera the die may be
configured to correspond in shape to the tablet configura
tions set forth above.
Tablets prepared in accordance with the invention per~i~
packaging material to be reduced in amount by as much as 20
to 25% in size, while package sheet thickness may be reduced
as much as 30%. Also, tablets of the present configuration
resist breakage and spalling during manufacture and shippinga
and the packaging machinery jamming is reduced due to a cor-
.responding reduction in the incidence of "shimming".
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The present invention is applicable to tablets for a varietyof uses extending from medicinal compounds to household goodsO
The exact angulation and size of individual tablets will be
governed by the materials being formed, however the basic
convex configuration is utilized in each instance.
Accordingly, it is a principal object of the present inven-
t;on to provide a tablet having at least one broad outer
surface with a convex cor,figuration.
It is a ~urther object of the present invention to provide
a tablet as aforesaid which realizes a savings in packaging
material.
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It is a fur~her object of the present invention to provide
a tablet as aforesaid which offers improved strength and
econ~my of processing.
It is a yet further object of the present invention to pro-
vide a method for preparing a tablet comprising forming the
broad surfaces of the tablet in convex relationship to each
otherO
Other objects and advantages will become apparent to those
skilled in the art from a review of the ensuing description
which proceeds with reference to the following illustrative
drawings.
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BRIEF DESCRIPTION OF THE DRAWINGS
- Figure 1 is a perspective view of a table~ prepared in
accordance with the present invention.
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Figure 2 is a side view illustrating -the tablet of Figure 1O
Figure 3A is a side sectional view illustrating a tablet
prepared in accordance with the prior art, enclosed in a
sealed package.
Figure 38 is a side sectional view similar to Figure 3A
illustrating the tablet of the present inventionO
Figure 4A is a top view partly in phantom illustrating the
tablet shown in Figure 3A.
Figure 4B is a top view partly in phantom illustrating the
tablet o~ Figure 3B.
2~ Figures 5 and 6 are side views illustrating tablets in
accordance with alternate embodiments of the present inven-
tion.
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FicJure 7 is a slde sectional view i:Llus-trating
an alternate tablet within a packacJe.
Fic~ure 8 is a perspective view o~ a fur-ther
alternate embodimen-t of -the presen~ invention.
ic3ure 9 is a perspective view of a further
embodiment of the present invention.
Figure 10 is a perspective view of a further
embodiment of the present invention.
D3~TAILED DESCRIPTION
Referring to the drawings, wherein like numerals
designate like parts, and particularly to Figures 1 and 2,
tablet 10 comprises pa red broad outer surfaces 12 generally
opposed to each other and terminatinc3 in substantially
parallel spaced apar-t surface perimeters 14. A continuous
rim 16 extends transversely between surface perimeters 1~
as shown, and may preferably define a cylinder as shown in
certain of the Figures.
As shown in Figures 1 and 2, both surfaces may
be convexly extended; however, the invention includes the
instance where only one surface 12 is convex, and this will
be described with reference to Eigure 7, later on
Broad surfaces 12, when convexly extended as
shown, comprises a central convex sec-tion 18 and a peripheral
convex section 20 -that is located annularly adjacent to it.
Preferably, sections 18 and 20 are integral with each other,
and may, as shown in Figures 6 and 7 ex-tend continuously
w:ith each other. Alternately, convex sections 18 and 20
may define ex-terior surEaces that are disposed at an angle
with respec-t to each other that may preferably be c3rea~er
than 180.
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In particular, and with reEerence to Figure 2, an angle ~ is
shown that is deEined by the exterior surfaces of convex
sections 18 and 20.
In a further aspect of the present invention, convex
section 20 may define a beveled surface that conforms to
the frustum
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of a cone, in the instance where -tablet 10 is circular in
shape. Similarly, convex section 18, while graduated at a
differing angle of inclination than that of section 20,
may define in one embodiment an essentially conical con-
figuration. The shape of respective convex sections 18
and 20 may accordingly vary, and, for example, as
illustrated in Figure 8, convex section 18' may deEine a
shape that is essentially pyramidal, in combination with
the essentially frustoconical shape of section 20. The
invention contemplates a variety of shape combinations
within its scope, and should not be limited to specific
combinations illustrated herein.
Referring further to Figures 1 and 2, in the
instance where convex sections 18 and 20 differ in slope
as shown, they define at their junction a continuous ridge
22 which, in the illustra-tions herein may comprise a
circle. The invention includes ridges having oval, square,
rectangular, and other shapes wi-thin its scope.
One of the importan-t aspects of the present
invention comprises the configuration of the peripheral
convex section 20. In particular, and with reference to
; Figure 2-3B, one of the advantages of the present con-
figura-tion is that it reduces the strain on the packaging
material in the instance where -the tablet is sealably
packaged within two parallel package sheets, and permits
reductions in both packaging sheet gauge and size, as will
be more particularly explained.
Referring to Figure 3B, a packaged tablet is
shown which comprises table-t 10 disposed within a package
2fi consisting of paired, opposed package sheets 26 that
have been peripherally bonded to each other, and in
their non-bonded area, define a
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package pouch 28 to hold the ~ablet. Correspondingly, Fig-
ure 3A i11ustrates a packaged tablet in accordance with the
prior art, and tablet 30 illustrated therein is thus enclosed
within a tablet package 32 prepared from paired sheets 34
likewise peripherally bonded to deFine a central package
pouch 36.
The differences between the respective packages include certain
visual distinctions that are readily apparent. For example~
tablet 30 utilizes essentially flat broad outer surfaces
Both packages utilize an identical angle of taper of the
package sheets to the point of sealable engagement. In each
instance, an acute angle, labeled ~`is defined between respect-
iYe sheets 26 in Figure 3B, and 34 in Figure 3A. Referring
back to Figure 2, the exterior surfaces of peripheral con-
1~ vex sections 20 preferably define an acute angle corresponding
- to angle ~ and therefore labeled identically, to facilitate
the reduction in the size of pouch 28.
More specifically, the taper of sheets 26 and 34, respectively3
begins at the tablet point bends 38 and 40, which mark the
point at which the taper of the packaging sheets is set to
occur. In both instances, the identical angle o~ taper ls
utilized, and it can be seen that the tablet of the present
invention permits the taper to commence earlier, thereby per-
mitting the pouch 28 to be defined within a smaller area9 and ~r
correspondingly to define a reduced volume. The configurationof tablet 10 permits the same amount of tablet material to be
contained within this smaller pouch, as that contained within
pouch 36 holding tablet 30. Referring now to Figures 4A and
4B, comprising plan views partly in phantom of corresponding
~igures 3A and 3B, it can be seen that the pouch 28 is reduced
in area from that of pouch 36 and a corresponding reduction
is possible in the overall size of sheet 26 from that of
sheet 34. It should be noted, that this reduction in packaging
material is possible without the requirement of a decrease in
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the diame-ter of the respec-tive -table-ts. Thus, the surEace
perimeter 1~ of table-t 10 is equal in size to the surface
perimeter 42 of -tablet 30, with the difference in the size
and location of -the respective tablet point bends 38 and
~0, accounting for the decrease in the size of pouch 28
over pouch 36.
In addition to the reduction in the si~e of the
packaging material, it has been found that the sheet ma-terial
itself may be reduced in gauge, as the overall convexity
of the outer surfaces 12 reduces -the strain on the sheet
materials that is normally imposed at the tablet point
bend in the instance where the tablet is flat-faced, as
illus-trated in Figures 3A and 4A. The size of the external
angle that is subtended by the central and peripheral
convex sections, de-termined with the tablet point bend 38 as
its apex, is thus less than the corresponding external angle
that is disposed with tablet point bend ~0 as its apex, in
Figure 3A. The package sheet 26 is therefore less likely
to rup-ture than corresponding package sheet 3~, due to
the configuration of respective tablets 10 and 30. Thus,
while package sheet 3~ has conventionally been prepared to
a -thickness of .001 gauge, package sheet 26 may be utilized
at a reduced thickness of .0007 gauge, and provides suf-
ficient package strength and integrity, -to resis-t rupture
and premature pac]cage leakage.
Several o-ther advantages have also been found
with the employment of the tablets of -the presen-t invention.
The problem referred to earlier with respect to tablet
packaging, comprising the -tendency of table-ts -to s-tac}c or
"shim" during conveyance to the package pouch, has been
virtually eliminated by the provision of the tapered sur-
faces of the convex broad outer surfaces 12. The -tapered
surfaces of the tablets allow them to slide apart from
each other so that individual -tablets may be efficien-tly
packaged without jamming package machinery.
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Also, the outer shape of the tablets confers a further un-
expected advantage, in the instance where the tablet includes
a cleansing composition that operates when the tablet is
dissolved to form a cleansing solution, such as in the instance
where denture cleansers, toilet bowl cleaners and the like are
prepared. When the tablet is dropped into the solution 5 the
tendency is genera~ly for the tablet to come to rest at the
bottom of the container, resting on one of its broad surfaces.
ln the instance where the broad surfaces are flat, the surface
area of the tablet available for interaction with the liquid
in the container is ~imited, as the surface in contact with
the bottom o~ the container is unexposed. By contrast, the
present tablet configuration presents tapered broad surfaces,
that would extend away from the bottom of the container and
1~ permit the liquid in the container to make surface contact
to accelerate the disintegration of the tablet.
The method for preparing the tablet of the present invention
comprises the preparation and use of tablet dies defining
concave broad surfaces that correspond in shape to the con-
vex broad outer surfaces desîred in the tablet. Thus, eitherone or both of the broad outer surfaces may be defined in
corresponding concavities within the tablet die, so that the
appropriately configured tablets may be ~repared. In other
respects, tablet preparation does not differ from that of the
prior art, as conventional tableting agents may be employed~
and convent;onal forming pressures, etc. may be utilized.
It is advisable to prepare the tablets of the present inven-
tion with essentially flat rims 16~ ~as this prevents the
occurrence of "shingling", ~ the surface dis-
continuities that sometimes are formed when the tablet edgeis rounded.
The tablets of the present invention may vary widely in exact
shape, so long as at least one o~ the broad outer surfaces is
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convexly extended as described. PreFerably, the broad outPr
surfaces are symmetrically convex.
The exact size of central convex section 18 may vary within
the scope of the invention, and may accordingly range in size
from 20X to 80b in radius, of the total radius of the broad
outer surface 12. Preferably, the central convex section may
range in size from 30 to 70% of the total radius, and most
preferably ranges from 50% to 65X. Also, in the instance
where the tablet possesses a configuration similar to that
of Figure 1, with a continuous ridge 22, the location of
ridge 22 naturally may vary, depending upon the size of the
central convex section.
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Referring now to Figure 5, the variation in the s;ze of the
respective convex sections is illustrated, as periphera~
convex section 20 appears larger than in Figure 2~ while
central convex section 18 is reduced. In Figure 6, a variant
tablet 44 is shown which utilizes broad surfaces 46 that
taper in convexity, so that the central convex section and
the peripheral convex section are continuous with each other~
All of the above variations are within the scope of the
present invention.
A further embodiment is illustrated in Figure 7, wherein a
tablet 48 is prepared which utilizes a single convex broad
outer surface 50. This embodimen~ is specifically utilized
in the instance where a package such as package 52 is em-
ployed. In such packages, only one of the sheets is expanded
and forms a pouch, and thus a flat sheet 54 has adhesively
bound thereto convexly expanded sheet 56, which deFines the
recess forming the tablet pouch 58. In this instance, it
is desirable to provide a flat broad outer surface as shown,
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however the advantages noted above with respect to the
bi-convex tablet also obtaln in the instance ~here the
single conYex surface is employed.
Figures Y and 10 illustrate a further embodiment~ wherein
the tablet is essentially rectangular ;n shape. Referrillg
to Figure 9, tablet 10" defines paired broad outer surfaces
12", w~ich can be seen to be convex, in similar fashion to
surfaces 12 of F;gure 1. Thus, surfaces 12" are comprised
of central con~ex sections 18", and peripheral convex sec-
lû tions 20" lying adjacent thereto. The separating ridge 22"may vary in configuration from that of a circle, illustrated
in Figure 1 and Figure 9 herein, to that of a rectangle fol-
lowing essentially in parallel fashion surface perimeter 14".
In the former ~nstance, peripheral convex section 20" appears
as four triangular subsections e~ually distributed in the corners
- of the rectan~ular perimeter 14", while in Figure 10, peripheral
convex section 20" is essentially rectangular and frames central
convex section 18".
The tablets of Figures 9 and 10 are further variant in the
.20 .configuration of the rim 16", as it can be seen to vary in
thickness from a minimal thickness at the cor~e~ of~hç tablet9
to a maximum thickness at the points centrally ~fY-i}~ the
corners. .
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The provision of a tablet in rectanyular configuration as
25 shown can be appreciated.to make further econom;c use of the ,
package pouch, as, in the instance where the po.uch is rec-
. tangular, the shape of the tablet assures complete utilizationof defined space. The other advantages discussed above with
respect to the tablet of the present invention are equally
demonstrated by this further embodiment, as the convex dis-
tention of the broad outer surfaces 12" reduces the strain
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that is normally imposed upon the package pouch.
As noted ear1ier, the tablets prepared in accordance with the
present invention may contain a variety of ingredients for
vari 0~5 uses, including household and medicinal application.
The present tab~et con~igurations are partioularly useful in
the instance where tablets are prepared for use as denture
cleansers, toilet bowl cleaners and the like. In such in-
stances, the table~ forming mater;al may include active ingred-
ients such as cleansers, pharmaceutical compositions, and the
like, again depending upon the particular utility of the tablet.
While there have been herein shown -and described the pre-
ferred embodiment of the present invention, it will be under-
stood that the invention may be embodied otherwise than as
herein specifically illustrated or described, and that within
such embodiment certain changes in the detail and construction,
and the ~orm and arrangement of the parts may be made without
departing from the underlying idea or principles of the in-
vention within the scope of the appended claims.
