Dental Mixing Capsule

Abstract

A capsule has a hollow body defining a first compartment having an open end which is closed by a retainer, the latter being telescopically mounted within the hollow body. The retainer defines a second compartment having an open end, the second compartment being isolated from the first compartment by a frangible partition, the latter being an integrally molded portion of the retainer. The first and second compartments are utilized for storing first and second ingredients respectively. To seal the second material within the second chamber, a cap having a plunger is telescopically mounted over the capsule body, with the end of the plunger extending into the open end of the second chamber in a sealing relationship therewith. To use the capsule to mix the ingredients, it is compressed endwise so as to force the plunger inwardly to increase the pressure on the second ingredient (preferably liquid), rupture the partition, and eject the second ingredient into the first chamber. The capsule is then shaken to mix the ingredients, and the cap and retainer are pulled from the body as a unit to provide access to the mixture. The capsule may be compressed by hand alone or with the assistance of a special tool.

Description

BACKGROUND OF THE INVENTION

This invention relates in general to a mixing capsule, but one particularly to a dental mixing capsule in which two or more ingredients are stored separately; the ingredients are subsequently brought together and mixed in the capsule.

In a conventional dental mixing cpasule, two or more ingredients of a filling material are stored in individual sealed compartments or chambers within the capsule. Examples of such a capsule are shown in each of the following patents: U.S. Pat. No. 3,451,540; U.S. Pat. No. 1,774,258; U.S. Pat. No. 3,595,439; U.K. Pat. No. 1,107,894; Austrian Pat. No. 188,032; German Auslegeschrift No. 2,009,403; and German Offenlegungschrift No. 1,955,996. Within such a capsule, there is usually a measured dose of one liquid ingredient and a measured dose of one solid ingredient, the latter preferably being in dry powdered form. In order to prepare the filling material, a partition separating the individual compartments is generally ruptured by endwise compression of the capsule so that the ingredients are brought together, and the ingredients are mixed by vigorously shaking the capsule; the mixture is then removed from the capsule for use.

Numerous problems are encountered in using the conventional capsules of the prior art. In many instances, a cap having a plunger is telescopically mounted to an open end of a hollow capsule body, and when it is desired to bring the ingredients together, the capsule is compressed endwise, thus pushing the plunger inwardly into the capsule body to rupture one or more frangible partitions. Because of a loose fit between the plunger and the inner peripheral wall of the capsule body, "splashback" (i.e., leakage of the liquid ingredient around the plunger) often occurs as the plunger moves inwardly. If an attempt is made to eliminate the "splashback" problem by dimensioning the diameter of the plunger so that there is a tighter fit between it and the peripheral wall of the capsule, a second problem is created; this latter problem is the considerable additional force now required to move the plunger inwardly because of the increased frictional resistance between the plunger and capsule body.

Other factors also contribute to requiring considerable force to move the plunger inwardly in conventional capsules. One of these factors is that in many instances, the plunger itself must directly rupture a first partition which covers the end of the capsule body. In such an instance, not only is considerable force required to move the plunger inwardly to rupture the end partition, but it is also very difficult to guide the plunger as it is moving. Some plungers have pointed cutters or projections which cut the partitions as the plungers are moved inwardly into the capsule body. In some instances, severed pieces of the partition then fall into and becomes mixed with the ingredients. In other instances the ruptured partition remains affixed to the capsule body, but becomes lodged between the plunger and the peripheral wall of the body; in at least one such capsule, this leaves a space between the plunger and the capsule body wherein portions of the ingredients become trapped.

Where the partition is a separate element which must be affixed to the capsule by an adhesive or other means, it is difficult to effect an air-tight seal between them; with such an arrangement, the partition as a whole may become detached, fall into, and become mixed with the ingredients when the plunger is moved inwardly. Also, in some conventional capsules, it is very difficult to remove the ingredients after they are mixed because of the peculiar construction of the capsules.

Consequently, what is needed, is a single capsule which overcomes these and other problems of the capsules of the prior art.

SUMMARY OF THE INVENTION

The present invention relates to a dental capsule having a hollow body which defines a first chamber having an open end, the first chamber being used to store a first ingredient. Closing and sealing the open end of the first chamber is a retainer which is telescopically mounted within the capsule body. The retainer defines a second chamber having an open end, the second chamber being isolated from the first chamber by a frangible partition which is an integrally molded portion of the retainer; the second chamber is used to store a second ingredient (preferably liqud). To seal the second ingredient within the second chamber, a cap having a plunger is telescopically mounted to the capsule body, one end of the plunger extending into the open end of the second chamber. A protrusion extends around the periphery of the plunger adjacent the one end thereof, the protrusion being dimensioned so as to have an interference fit with the peripheral wall of the second chamber; this assures that an air-tight seal is formed between the plunger and the retainer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the preferred embodiment of the assembled capsule ready for use.

FIG. 2a is a longitudinal sectional view taken along line 2a--2a of FIG. 1.

FIGS. 2b, 2c, and 2d are longitudinal sectional views similar to FIG. 2a, but showing the component parts of the capsule in various positions during the use of the capsule.

FIG. 3 is a sectional view taken along line 3--3 of FIG. 2a and showing prescored lines on the partition.

FIG. 4 is a sectional view taken along line 4--4 of FIG. 3.

FIG. 5 is a longitudinal sectional view of a modified capsule which is used for storing three ingredients separately.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIGS. 1 and 2, the capsule 10 is comprised of three main component parts, a cap 12 and a capsule body 14, each of which has a plurality of longitudinally extending ridges 16 formed thereon, and a retainer 18. The ridges 16 aid in grasping and manipulating the capsule during use. Although other materials may be used, high density polyethylene is a suitable material to use in molding the cap 12 and the body 14, and low density polyethylene is a suitable material to use in molding the retainer 18.

As can be seen, the body 14 defines a chamber 20, the latter having a circular cross-section and being symmetrically disposed about an axis 22. Chamber 20 is utilized to store a predetermined amount of a first ingredient 24 (e.g., a powdered silver alloy or other flowable substance). The opening 26 at one end of the chamber 20 is closed by the retainer 18 which is telescopically mounted within the body 14. The body 14 defines a concave surface 28 for closing the other end of the chamber 20.

The retainer 18 defines a second chamber 30 which is also symmetrically disposed about axis 22 when the retainer is telescopically mounted within body 14, the bottom of chamber 30 being defined by an annular shoulder 32 which surrounds a frangible partition 34; the partition 34 is an intergrally molded portion of the retainer 18. Chamber 30 is utilized to store a predetermined amount of a second ingredient 36 (e.g., mercury or other flowable substance) which is to be subsequently mixed with ingredient 24. To stop the retainer 18 at a predetermined location when initially mounting it within the body 14, an annular flange 38 is provided; the latter also prevents the retainer from being pushed further into the body 14 when the cap 12 is pushed into the retainer 18. It is noted that a pair of prescored lines or depressions 40 and 42 (FIGS. 3 and 4) are formed in partition 34 to define a weakened zone along which the parititon may be more easily ruptured when it is desired to use the capsule to mix ingredients; these lines intersect in the center of the partition 34. An opening which is defined by concave surface 41 extends from the partition 34 toward the other end (i.e., toward surface 28) of the body 14. As will be apparent from the description which follows, surface 28 and 41 promote movement of the ingredients throughout chamber 20 during the mixing operation.

To seal the ingredient 36 within the chamber 30, the cap 12 is telescopically mounted to the body 14 so that one end of plunger 44 enters the opening 46 at one end of the chamber 30. An annular protrusion 48 extends around the periphery of the plunger 44 adjacent the one end thereof, the protrusion being dimensioned so as to have an interference fit with the annular wall defining chamber 30. In its initial position (that shown in FIG. 2a), the end of plunger 44 extends into the retainer 18 so that the protrusion 48 is in contact with the annular wall defining chamber 30. As the plunger 44 is pushed inwardly into the retainer 18, the material from which the retainer is made of "flows" around the protrusion 48. With this arrangement, an air-tight seal is formed between the retainer 18 and the plunger 44. As stated above, the annular flange 38 prevents the retainer 18 from being pushed further into the body 14 when the plunger 44 is pushed into the retainer 18.

The cap 12 also includes an annular skirt 50, the latter surrounding the body 14. Extending around the inner annular peripheral surface of the skirt 50, is an annular protrusion 52, the latter being in sliding contact with the outer peripheral surface of the body 14. The protrusion 52 serves to guide the cap 12 as the plunger 44 is pushed inwardly into the retainer 18. As shown in FIG. 2a, the end of plunger 44 has an incline or bevel 53 formed thereon, the incline extending from adjacent the periphery of the plunger toward the center thereof, and toward the partition 34.

When it is desired to use the capsule 10 to mix the ingredients 24 and 36, the capsule is compressed endwise so as to push the plunger 44 inwardly from is initial position into chamber 30 against ingredient 36. Because the latter is a liquid (i.e., mercury) in the present example, this increases the hydrostatic pressure sufficiently to rupture partition 34 along the lines 40 and 42, the four ruptured segments of the partition forming an opening 54 through which the mercury is ejected into chamber 20 (FIG. 2b). As stated above, the protrusion 48 prevents mercury from excaping around the plunger 44 ("splashback") as the plunger is pushed inwardly into chamber 30. It is apparent that with the present embodiment, there are no severed pieces of the partition to fall into the chamber 20. As compared to some of the conventional capsules of the prior art which were discussed above, considerably less force is required to push the plunger 44 inwardly into the retainer 18, because the frictional resistance between the protrusion 48 and the annular wall defining chamber 30 is relatively small as compared to a conventional plunger which has a uniform diameter along its entire length, but which diameter is likewise dimensioned so as to have an interference fit with the retainer; also, as compared to the latter instance, the protrusion 48 forms a superior seal between it and the retainer 18, because the material from which the retainer is molded "flows" around the protrusion as the plunger 44 is pushed inwardly into the retainer.

The plunger 44 is pushed inwardly until the end thereof abuts the annular shoulder 34 (FIG. 2c). At this point, the incline 53 prevents the ruptured partition 34 from closing completely and assures that all of the mercury has been ejected from chamber 30.

After all the mercury from chamber 30 has entered chamber 20, the capsule 10 may then be placed in an amalgamator for the mixing operation. A suitable amalgamator for this purpose is the CAPMASTER amalgamator sold by the S.S. White Division of Pennwalt Corporation. Concave surfaces 28 and 41 serve to assure that the ingredients are thoroughly mixed by promoting movement of the ingredients throughout chamber 20 as indicated by the arrows 56. To assure that the retainer 18 is pulled from the body 14 along with the cap 12, the fit between the protrusion 48 and the retainer 18, and the fit between the latter and the body 14 are closely controlled. Except for the fange 38, the outer diameter of the retainer 18 is uniform along its length. The inner diameter of the body 14 (that defining chamber 20), however, varies along its length, the inner diameter being the largest at the open end of chamber 20. The outer diameter of retainer 18 and the inner diameter of body 14 are dimensioned so that when the retainer is mounted in its initial position (that shown in FIG. 2a), there is an interference fit between the body 14 and the inner end of the retainer 18 which will prevent leakage from chamber 20, but will allow the retainer 18 to be pulled from the body 14 as a unit with the cap 12 (FIG. 2d) when the mixing is completed.

Referring to FIG. 5, a modification is illustrated which is utilized for storing 3 ingredients. The body 14' has been modified so that each end of chamber 20' now has an opening 26'.

Each opening 26' is closed by the identical cap and retainer arrangement illustrated in FIGS. 1 through 4, the lower retainer (as viewed in FIG. 5) now serving to store the extra third ingredient 36' (preferably a liquid) in its chamber 30.

Claims

What is claimed is:

1. A mixing capsule for storing at least two ingredients separately until said ingredients are subsequently brought together and mixed within said capsule, said capsule comprising:

a. a body defining a first chamber having an opening at one end thereof and being adapted to store a predetermined amount of a first of said ingredients,

b. a retainer telescopically mounted to said body and closing said opening at said one end of said first chamber, said retainer having means including a peripheral wall and a frangible partition molded integrally with said peripheral wall for defining a second chamber, said second chamber having a first opening at one end thereof and being adapted to store a predetermined amount of a second of said ingredients, said partition being disposed at said other end of said second chamber and having at least one pre-scored line formed therein defining a weakened zone which is adapted to be ruptured so as to define a second opening at said other end of said second chamber, said pre-scored line being formed on the side of said partition which is adjacent said first chamber, said retainer being disposed on said body so that said partition isolates said first chamber from said second chamber prior to said partition being ruptured,

c. a cap having a plunger, said plunger having an end adapted to be inserted into said opening in said one end of said second chamber, said plunger having a protrusion extending around the periphery thereof adjacent said end thereof, said protrusion being dimensioned so as to have an interference fit with said peripheral wall, said plunger extending into said second chamber, so that said protrusion is in contact with said peripheral wall adjacent said first opening of said second chamber to seal said second ingredient therein, the cross-sectional area of said first and second chambers each being larger than the cross-sectional area of said partition, the fit between said body and said retainer, and between said retainer and said protrusion being such that said ingredients are sealed within said chambers, but which will permit said cap and said retainer to be pulled as a unit from said body,

d. said capsule having means for stopping the telescopic movement of said retainer with respect to said body when initially assembling said capsule so as to locate said retainer at a predetermined position and prevent further movement of said retainer when said plunger is pushed into said second chamber,

e. said retainer being disposed at least partly within said body, said cap including a skirt surrounding said body, said skirt having a protusion extending around the inner peripheral surface thereof, said protrusion being in sliding contact with the outer peripheral surface of said body,

f. whereby when it is desired to use said capsule to mix said first and second ingredients, said capsule is compressed endwise so as to move said plunger from its initial position inwardly into said second chamber to pressurize said second ingredient, rupture said partition, and eject said second ingredient into said first chamber where it is brought together with said first ingredient, and after mixing said ingredients within said capsule, said cap and said retainer are pulled as a unit from said body to allow the mixture to be easily removed from said first chamber.

2. A mixing capsule as set forth in claim 1, wherein said retainer includes means defining a shoulder surrounding said partition and facing said first opening of said second chamber, said shoulder being adapted to stop the inward movement of said plunger into said second chamber, said end of said plunger being inclined from adjacent the periphery thereof from completely closing, thus assuring that all of said second ingredient is ejected from said second chamber.

3. A mixing capsule as set forth in claim 2, wherein said first and second chambers each has a circular cross-section, said capsule including means defining a concave surface closing said other end of said first chamber, and said retainer including a surface defining a retainer opening extending from said partition toward said other end of said first chamber, at least a portion of said retainer opening having an increasing circular cross-sectional area as it extends toward said other end of said first chamber.

4. A mixing capsule as set forth in claim 1, wherein the other end of said first chamber has an opening therein, said capsule further including:

a. a second retainer telescopically mounted to said body and closing said opening in said other end of said first chamber, said second retainer having means including a peripheral wall and a frangible partition molded integrally with said latter peripheral wall for defining a third chamber, said third chamber having a first opening at one end thereof and being adapted to store a predetermined amount of a third of said ingredients, said latter partition being disposed at said other end of said third chamber and being adapted to be ruptured so as to define a second opening at said other end of said third chamber, said second retainer being disposed on said body so that said latter partition isolates said first chamber from said third chamber prior to said latter partition being ruptured,

b. a second cap having a plunger, said latter plunger having an end adapted to be inserted into said opening in said one end of said third chamber, said latter plunger having a protrusion extending around the periphery thereof adjacent said end thereof, said protrusion being dimensioned so as to have an interference fit with said latter peripheral wall, said latter plunger extending into said third chamber so that said protrusion is in contact with said latter peripheral wall adjacent said first opening of said third chamber to seal said third ingredient therein, the cross-sectional area of said first and third chambers each being larger than the cross-sectional area of said partition,

c. said capsule having means for stopping the telescopic movement of said second retainer with respect to said body when initially assembling said capsule so as to locate said second retainer at a predetermined position and prevent further movement of said second retainer when said latter plunger is pushed into said third chamber.

5. A mixing capsule as set forth in claim 4, wherein said third chamber has a circular cross-section, and wherein said second retainer includes a surface defining a retainer opening extending from said latter partition toward said one end of said first chamber, at least a portion of said latter retainer opening having an increasing circular cross-sectional area as it extends toward said one end of said first chamber.

6. A mixing capsule as set forth in claim 5, wherein said second retainer is disposed within said body, and wherein said second cap includes a skirt surrounding said body, said latter skirt having a protrusion extending around the inner peripheral surface thereof, said latter protrusion being in sliding contact with the outer peripheral surface of said body.

7. A mixing capsule as set forth in claim 1, wherein said second opening at said other of said second chamber is sufficiently restricted so that said second ingredient is ejected in the form of a forceful jet stream which will reach said other end of said first chamber.