US3651932A - Duplex capsule for dental filling material - Google Patents

Abstract

A capsular container of the duplex type for dental purposes having a substantially rigid container body containing a first component or ingredient and having a perforated wall in which at least one opening is formed to a bag of frangible foil material for receiving a liquid component which when pressed against the perforated wall discharges its contents into the container.

Description

United States Patent Miihlbauer 51 Mar. 28, 1972 54] DUPLEX CAPSULE FOR DENTAL 2,561,071 7/1951 Prisk ..128/272 FILLING MATERIAL 2,764,983 10/1956 Barasch et al. ..l28/272 3,190,499 6/1965 Dow ...;206/47 A [72] Inventor: Ernst A. Muhlbauer, Hamburg, Germany 3,415,360 12/1968 Baumann et A M m206/47 A [73] Assignee: Zahn-Porzellan KGE Muhbauer & C0,, 3,425,598 2/1969 Kobemick ..206/47 A Hamburg, Germany Primary ExaminerWilliam T. Dixson, Jr. [22] Filed. Oct. 9, 1969 Atmmey John Lezdey [211 App]. No.: 865,124

[57] ABSTRACT [52] US. Cl. ..206/47 A, 206/635, 128/272 A capsular container f the duplex type f dental purposes [51] Int. Cl ..B65d 81/32 having a Substantially rigid container body containing a first [58] Field oISearch ..206/47 A, 56 AA, 63.5; 215/6, component or ingredient and having a perforated wall in 215/1 C; 128/272; 100/233 which at least one opening is formed to a bag of frangible foil material for receiving a liquid component which when pressed [56] References Cite? against the perforated wall discharges its contents into the UNITED STATES PATENTS comamer- 2,420,142 5/1947 Levin 100/233 10 Claims, 10 Drawing Figures PATENTEDMAR28 I912 335L932 .SHEET 1 BF 2 Fig. I

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ATT'oRN Y PATENTEDMAR28 [s72 SHEET 2 [)F 2 v Fly. 4

ERNST A. MuhLaAuzk BY WM ATToRNEy DUPLEX CAPSULE FOR DENTAL FILLING MATERIAL The invention relates to capsular containers for storing separately components or ingredients which are to be later mixed together to produce a dental filling material, such as an amalgam, alloy or cement. More particularly, the invention relates to a capsular container of the duplex type for dental purposes comprising a substantially rigid container body containing a first component or ingredient and having a perforated wall in which at least one opening is formed, a bag of frangible foil material receiving a liquid second component and maintained in contact with said perforated wall of the container and capable of being caused, when pressed against the said perforated wall, to burst in the area of said at least one opening whereby its content is discharged into the container.

ln known duplex capsules of this general class, the bag is maintained in contact with the perforated wall by means of a closure member adapted to be telescoped over the container. The bag is loosely inserted in the space defined by the container and closure member.

It is an object of the present invention to simplify the known duplex capsule and this object is achieved, by this invention, by securing the bag of foil material in exposed position on top of the perforated wall.

In this conjunction the foil material of that portion of the bag which faces the container is preferably made weaker than the outwardly facing portion. Although, in accordance with this invention, the bag may be secured to the perforated wall by bonding or pasting; it may instead be suitable to connect the edge of the bag to the container wall by heat sealing.

Emptying of the bag for transferring its contents into the container may be done, for example, by thumb pressure applied against the bag. It has been found that this way of proceeding will ensure satisfactory, uniform and complete emptying of this bag.

When using such duplex capsules, it is in most cases necessary to completely or substantially completely empty the bag, except for a small residual quantity which should be the same in each instance, in order to ensure a specified ratio of mixture between the two components. Undesirable backflow of a portion of the liquid into the bag of foil material may occur when the wall of the bag remote from the container exhibits a tendency to spring back when released after compression whereby the capacity of the emptied bag is increased, causing the liquid to return into the bag by suction.

it has been found that backflow of the liquid can be prevented when, in accordance with the present invention, the diameter of the opening in the container wall facing the bag is made very small. When, for example, the liquid component is relatively viscous, as is frequently the case in dentistry, a diameter of a few tenths of a millimeter will be sufficient.

On the other hand, when the openings are narrow, the effort required to cause the frangible foil of the bag to burst is higher than when the openings are wide.

in accordance with the invention the advantages of wide openings on one hand and narrow openings on the other may be combined by providing a flaring opening having a large diameter on the side facing the bag and a small diameter on the side facing the chamber of the container.

Instead or additionally, the bag may be so shaped and arranged that the backflow tendency is avoided or reduced. This is achieved, in accordance with the present invention, by so providing the wall of the bag remote from the container, i.e. that wall which is to undergo a deformation when emptying the bag, that is has a stable dwell condition when in bag emptying position.

This stable dwell condition of this wall may be preferably created, in accordance with the invention, by biasing this wall toward such dwell position. This requires that the bag, when in filled condition of the bag for storage of the container, is resilienty expanded. Thus, the contents of the bag are permanently subjected to a certain pressure, which may be advantageous because the effort required for destroying the partition is thereby reduced. Should it be desired, however, to

avoid such a pressure condition for some reason, the deformable wall of the bag remote from the container may be of the bistable resilient type permitting it to assume a respective one of two stable dwell positions, when the bag is filled and when the frangible wall facing the container has been destroyed and the volume capacity of the bag has been reduced.

As an alternative, it may be desirable to make the bag wall remote from the container capable of plastic deformation and, in this conjunction, to assure by appropriately selecting the material and the shape, that the resilient returning bias becomes negligible. This can be ensured in most cases even through the material may have a certain inherent resilience by imparting to the bag wall remote from the container a dished shape capable of being reversed under the deforming pressure. lt will be understood that intermediate solutions between a resiliently bistable wall which, upon application of pressure thereto, will snap from one to the other of two positions and a purely plastically deformable wall may be imagined, and, as a matter of fact, are of particular advantage. A combination of the bistable resilient proporties and plastic deformability can be obtained by selecting for the wall a commercially available synthetic, such as polyvinyl chloride, polyethylene or a polyamide.

In this conjunction, it is highly expedient to provide the bag wall in contact with the container with a shape matched to that which the deformable wall will assume in the condition of reduced bag volume. ln particular, the deformable wall may be so constructed and arranged as to entirely or partially engage or directly contact the perforated wall or as to be but slightly spaced therefrom when the bag has been emptied. This will minimize the residual quantity of the bag contents.

Although it has been stated above in conjunction with this invention that the bag wall remote from the container should have certain properties preventing the backflow of liquid into the bag, it will be understood that these properties may be provided by a separate wall secured to and cooperating with the container to enclose the entire bag and which is not an integral part of the bag. Emptying of the bag and the transfer of its contents into the container may be performed by a special tool comprising two elements adapted to be forced against each other (such as by the lever action of tongs) with one of these elements acting against the bag of foil material and the other acting against some part of the container remote from the bag. The element acting upon the bag is preferably provided with a recess for receiving the portion of the container supporting the bag, and in this conjunction, the bottom of such recess which acts on the bag is preferably made resilient or provided with a resilient layer, such as a small plate or strip of rubberlike elasticity. It is generally known that such an elastic surface enhances uniform emptying of the bag.

A few advantageous embodiments of the invention will now be described by way of example and explained in more detail with reference to the schematic drawings, wherein FIG. 1 is an enlarged longitudinal section through one embodiment of the duplex capsule of this invention;

FIG. 2 shows a tool for use in emptying the bag of foil material and transferring the contents into the container;

FIG. 3 to 5 are longitudinal sections of the embodiment of FIG. 1 in three consecutive stages of use;

FIG. 6 is a showing of a second embodiment;

FIG. 7 shows an embodiment having a resilient perforated wall; and

FIG. 8 to 10 are longitudinal section of a further embodiment wherein both walls defining the bag of foil material are resiliently deformable, the embodiment being shown in three consecutive stages of use.

Referring now to the drawings, the container 1 defines a chamber 2 which receives one of the ingredients or components to be mixed and which serves as a mixing chamber. This space is closed by a closure member 3. The container 1 is substantially cylindrical, the section shown in the figure being taken on the cylinder axis. The container wall 4 remote from the closure member 3 (as viewed from the outside) is slightly concave arid provided with an opening 5 through its center. A

' bag 6jof foil material is secured to rest against the outer face of wall 4 and Comprises a wall 7 of foil material facing the container and an outwardly facing wall 8 of foil material remote from the container, the two walls being joined together along their edges 9 by heat sealing. The bag 6 contains a liquid component or ingredient. As regards the other component or ingredient which is disposed in chamber 2, it makes no difference whether it is liquid or, as in most cases, powdered.

The bag'of foil material is affixed to the outer face of wall 4, such as by bonding,'or it has its periphery 9 heat sealed to a peripheral portion of the container 1. The said two altematives may also be used in combination. When the bag is to be emptied and its contents are to be transferred into the cavity 2 of the; container by application of thumb pressure, it is not necessary to provide any bag portion of reduced strength in the area of opening 5 in order to prevent the bag from bursting at some other location, because the surface of the tip of the thumb is greaterthan the outer face of the bag. Thus, when applying the thumb to the bag, the thumb will cover the outer surface of the bag entirely before a pressure becomes effective tocause'the bag to burst, whereby the pressure applied to the outer'face of the'bag is uniform and prevents the foil material 8 of the bag from bursting in or near this area. However, in order to assure that the foil material 8 will be prevented from bursting at any undersired portion in the event that the pressure applied to the bag is not uniform or that an unyielding object is used for applying the pressure, that bag is preferably so shaped and arranged that its weakest wall portion is disposed near the opening 5, thus ensuring that it will burst in the area of the opening, permitting the contents to be reliably discharged into chamber 2. Thus, the foil material of wall 8 may be made of a stronger material than wall 7. Since, the foil material of wall 7 is not exposed to external forces, it may very well be made of a very thin material, e.g. of a filmy synthetic foilwhich is merely required to resist chemical attack by the two components and to have appropriate sealing characteristics. The outer wall'8 may, on the contrary, be made of aluminum foil coated with plastic on the inside for protection from chemical attack. Likewise, the heat sealed seam along edge should be made wide and strong enough in order to safely prevent the bag from bursting in this place. The edge portion 9 could further be additionally reinforced. Thus, the bag of foil material could be'initially produced with a diameter somewhat in excess of the outer diameter of wall 4 and the extreme outer marginal edge of this seam may than be folded back inwardly at a 180 angle in a direction such that the stronger foil material of wall 8 becomes disposed on the outside of the seam. This backfolded marginal strip may then be connected to the container body 1, such as by heat-sealing. Nornfrally, however, such additional provisions are not required iri' order to ensure that the bag will burst in the area of the-opening 5.

Referring now to FIG. 2, a tool for emptying the bag 6 and for transferring its contents into the container chamber 2 is constructed in the manner of a pair of tongs having two legs 10 and.l l"pivotally connected at 12. Leg 10 has a cylindrical recess l3'with a further rubber pad 14 inserted therein and possibly fixed to the bottom thereof by bonding. Leg 11 has a semispherical recess 15.

When using a capsule 16 in accordance with the present invention, it is placed into to tool with the bag 6 of foil material pointing 'downwardly and inserted in the recess 13, whereby thewall 8 tests on the resilient pad 14. Leg II is then pressed down .as indicated by arrow 16, whereby the semispherical closure member 3 of the capsule is received in recess 15. As the force applied is increased, an increasing pressure is applied to bag 6 through the rubber pad 14 and the bag wall 8 untilthe bag bursts in the vicinity of opening 5, permitting the contents to flow into the container chamber 2.

The material selected for the pad I4 is preferably so soft, that by the time the ultimate or bursting pressure is reached, it will'have fully engaged the outer wall 8 of the bag, thus fully supporting the latter and preventing bursting thereof at any undesired location even if its strength should be locally reduced for some uncontrolled reason.

In order to empty the bag 6, the outer wall 8 is placed in position 8'. When the bag 6 has the shape of a lentil as illustrated, wall 8 because of the vault effect, retains position 8, provided it has been made of material of sufficient rigidity, such as e.g. metal foil.

It is usual when mixing the two components to use vibration mixers. In accordance with the invention, such vibrating apparatus may be combined with a tool of the type illustrated in FIG. 2. In this case, the capsule is inserted into the mixing apparatus while in its initial condition, subsequently the bag 6 is emptied and its contents are transferred into the container 1 while the latter is supported in the mixing apparatus and finally the mixing operation is performed.

It will be noted from FIG. 1 that the opening 5 tapers inwardly toward the container. In other words, the opening provides a passage having a comparatively large diameter at the end facing the bag and having a comparatively small clear width at the end facing the mixing chamber 2. Thus, the opening is of a size at the end facing the bag which will facilitate the bursting of the bag, while being so narrow at its end facing the mixing chamber that the relatively viscous liquid forced out from the bag 6 into the mixing chamber 2 will be prevented from flowing back into the bag in the event that the bag should tend to return from its position shown in phantom and to thereby apply suction to the area of the opening.

As an illustrative example, it has been found that an opening tapered toward the mixing chamber and having a diameter of approximately 3 millimeters at the end facing the bag and a diameter of a few tenths of a millimeter, preferably of from 0.2 to 0.5 millimeters, at the end facing the mixing chamber will, on one hand, not impede the bursting of the bag and, on the other, safely prevent any appreciable quantities of the liquid from returning from the chamber 2 to the bag 5 under the action of suction.

It will be understood by a any skilled person that bursting of the bag in the area of the opening 5 can be assured by provisions other than by the use offoil materials of different thickness for walls 7 and 8. Thus, for example, foil 7 might be provided in the area of this opening with preconditioned portions of reduced strength, such as by scoring. As an alternative, the edge of the opening 5 could be provided with points facilitating the rapture of the foil material of wall 7 when pressure is applied.

The embodiment of a duplex capsule schematically illustrated in FIG. 3 to 5 is substantially similar to that of FIG. I. The three figures illustrate the bag emptying operation. FIG. 3 shows the initial condition of the capsule; FIG. 4 illustrates how pressure is applied to the bag with the tip of a thumb; and FIG. 5 illustrates the capsule after the bag 6 has been emptied. In the latter condition, the outer wall 8 of the bag, which is made of a relatively thick material, is dished the other way as compared to the condition shown in FIG. 3 and will retain this reversed dished configuration owing to the dome or vault effect, which is independent from the type of foil material employed. It will be understood, however, that the resistance opposed by the foil material of wall 8 to such reversing action will be less when it consists of, or when it comprises, a plastically deformable material, e.g. when it consists of aluminum foil having the inner face coated with plastic.

Foil 8 could also consist of a resilient material, such as of a synthetic resin having resilient properties. When the degree to which wall 8 is dished is or is substantially as shown in the drawing, it will exhibit bistable properties, which means that it will snap from the position shown in FIG. 3 into the position shown in FIG. 5 with a jerk when, by applying an initial pressure, the wall 7 has been ruptured and when a threshold value of resistance has been overcome.

As an alternative, the construction may be such that the wall 8, instead of being springy or resilient is, in the condition shown in FIG. 3, resiliently prestressed in such manner that it tends to snap over into the position shown in FIG. 5, whereby the effort required for deforming this wall is correspondingly reduced.

The description with reference to FIG. 3 to 5 applies to the embodiment of FIG. 6 with the exception that the bag is enclosed in a separate chamber, which may be of a certain advantage as regards manufacturing techniques. In this case, the functions described above with reference to wall 8 are performed by a wall 20, which, consequently, is to have the properties defined above with reference to the material of wall 8.

FIG. 7 .shows an embodiment of the container having a deformable perforated wall 4. In this embodiment, the perforated wall 4 is shown in full lines in the container storage position, in which it is resiliently prestressed toward a dwell position in which it substantially engages the inner face of wall 8, as shown in dotted lines. When the container is being stored, the movement of the perforated wall 4 toward its dwell position is, however, prevented by the counteracting pressure of the liquid component contained in bag 6. The opening 5 is sealingly closed by the wall 7 of foil material, which may either be bonded between the edge portions as described with reference to the embodiment shown in FIG. I to 3 or it may be adhesively bonded to the wall 4 of the container, or else it may be an integral part of the perforated wall 4 which just sealingly covers up the opening 5. The foil is adapted to be ruptured by merely applying a slight deforming pressure to the wall 8 or by means ofa spike 18 provided on wall 8 and capable, upon application of a slight pressure to wall 8, to pierce through the foil which obturates the opening 5. When the foil material of wall 7 has been punctured in this manner, the perforated wall 4 snaps over to the position shown in dotted lines, whereby the liquid contained in bag 6 is forced into the mixing chamber 2.

In the embodiments shown in FIG. 8 to 10, both the wall 8 and the perforated wall 4 are prestressed toward each other when in their container storage positions (FIG. 8 in such manner that they tend to mutually engage. Both walls should therefore be made of an appropriately resilient material. In accordance with one of the alternatives previously described in this specification, opening 5 is closed by the foil material of wall 7. When a pressure is applied to the wall 8 as shown in FIG. 9, the stress acting on the entire perforated wall 4 and on the foil material of wall 7 resting thereon is further increased, whereby high tangential stresses are developed in wall 7 finally causing the foil material thereof to be torn apart. The effort required to produce this effect is less than that required to cause the foil material to burst as in the embodiments of FIG. 3 to 5. As soon as the foil material is torn, walls 8 and 4 assume the positions shown in FIG. 10, whereby the liquid content of the bag is forced out into mixing chamber 2 through opening 5.

It will be understood that the opening 5 of the perforated wall 4 in FIG. 8 to 10 could take a form other than that of a passage having a circular cross section, such as that of a slot extending in the direction of a diameter or that of a plurality of slots which intersect at the center.

Although this invention has been described with reference to specific embodiments and materials, it will be clear to those skilled in the art that many variations and modifications may be made from the specific details set forth in this specification whithout departing from the inventive concepts disclosed herein.

I claim:

1. A capsular container of the duplex type for dental purposes comprising a substantially rigid container body having a chamber containing a first component and a perforated wall with at least one opening, and a bag of frangible foil material containing a liquid second component, said bag secured in exposed position on top of the perforated wall of said container body said bag having the foil material of the bag wall facing the container body consisting of less strength than that of the exposed bag wall and said exposed bag wall having a dwell position of stability defining the bag in empty condition whereby when the bag is pressed against the perforated wall, the bag burst in the area of at least one opening and its contents are discharged into the container.

2. The capsular container of claim 1 wherein said bag is adhesively bonded to the container wall.

3. The capsular container of claim 1 wherein the peripherial portion of said bag is heat sealed to the container wall.

4. A capsular container of claim 1 wherein said opening is tapered from a diameter of more than 1 millimeter at the end facing said bag to a diameter of a few tenths of a millimeter at the end opening into said chamber.

5. The capsular container of claim 4 wherein the diameter of said opening at its end opening into said chamber is from 0.2 to 0.5 millimeters.

6. The capsular container of claim 1 wherein the bag wall remote from said container body is biased toward said dwell position, the bias being opposed by the contents of the bag as long as the wall facing the container body is intact.

7. The capsular container of claim 1 wherein the bag wall remote from said container body is bistable by being adapted to assume a respective one of two dwells positions in the filled and empty condition of the bag.

8. The capsular container of claim 1 wherein the bag wall remote from said container body is plastically deformable.

9. The capsular container of claim 1 wherein the bag wall remote from said container body is of a dished shape capable of being reversed by a pressure applied to its convex face.

10. The capsular container of claim 1 wherein the bag wall facing said container body is matched in shape to the shape which the bag wall remote from said container body will assume in the empty condition of said bag.

Claims (10)

1. A capsular container of the duplex type for dental purposes comprising a substantially rigid container body having a chamber containing a first component and a perforated wall with at least one opening, and a bag of frangible foil material containing a liquid second component, said bag secured in exposed position on top of the perforated wall of said container body, said bag having the foil material of the bag wall facing the container body consisting of less strength than that of the exposed bag wall and said exposed bag wall having a dwell position of stability defining the bag in empty condition whereby when the bag is pressed against the perforated wall, the bag burst in the area of at least one opening and its contents are discharged into the container.

2. The capsular container of claim 1 wherein said bag is adhesively bonded to the container wall.

3. The capsular container of claim 1 wherein the peripherial portion of said bag is heat sealed to the container wall.

4. A capsular container of claim 1 wherein said opening is tapered from a diameter of more than 1 millimeter at the end facing said bag to a diameter of few tenths of a millimeter at the end opening into said chamber.

5. The capsular container of claim 4 wherein the diameter of said opening at its end opening into said chamber is from 0.2 to 0.5 millimeters.

6. The capsular container of claim 1 wherein the bag wall remote from said container body is biased toward said dwell position, the bias being opposed by the contents of the bag as long as the wall facing the container body is intact.

7. The capsular container of claim 1 wherein the bag wall remote from said container body is bistable by being adapted to assume a respective one of two dwells positions in the filled and empty condition of the bag.

8. The capsular container of claim 1 wherein the bag wall remote from said container body is plastically deformable.

9. The capsular container of claim 1 wherein the bag wall remote from said container body is of a dished shape capable of being reversed by a pressure applied to its convex face.

10. The capsulaR container of claim 1 wherein the bag wall facing said container body is matched in shape to the shape which the bag wall remote from said container body will assume in the empty condition of said bag.

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