Patent Abstract:
An ampule having a body portion and a sealed end portion and a sealed delivery portion adapted for use in a delivery syringe system for controllably dispensing a low viscosity material, such as a liquid, gel, or paste. An ampule having sealed rear portions adapted to mate with a plunger of a syringe so as to facilitate controlled dispensing of a low viscosity material. The syringe has a breach positioned to provide controlled flow of the dispensed low viscosity material and facility easy removal from the syringe. Low viscosity materials, such as liquids and gels, are controllably dispensed in a measured unit dose quantity. The present invention has many applications, but is particularly applicable to dispensing low viscosity materials such as used in coatings and not injected parenterally, and is particularly applicable to dental applications.

Full Description:
RELATED APPLICATION 
   This application is a divisional of U.S. patent application Ser. No. 09/399,891 filed Sep. 21, 1999, now U.S. Pat. No. 6,328,715, which is herein incorporated by reference. 

   FIELD OF THE INVENTION 
   The present invention relates in general to the placement of low viscosity material, and particularly to a collapsible cartridge or ampule and syringe for dispensing low viscosity material. 
   BACKGROUND OF THE INVENTION 
   In many applications, such as medical or industrial applications, and in particular dentistry, it is desirable to place accurately a low viscosity material. In dentistry in particular, there are many devices to apply a high viscosity material such as various cartridges and syringes. For example, a cartridge for dispensing a high viscosity material is disclosed in U.S. Pat. No. 4,963,093 entitled “Dental Syringe Tip And Syringe Holder Therefor” issuing to Dragan on Oct. 16, 1990. Therein disclosed is a syringe tip constructed to minimize the entrapment of air by the material being extruded. The cartridges generally contain relatively viscous material requiring a syringe having a mechanical advantage for dispensing the material. Such a syringe is disclosed in U.S. Pat. No. 5,125,836 entitled “Easy Loading Manual Extruder For Viscous Material” issuing to Dragan et al on Jun. 30, 1992. Therein disclosed is a syringe having a mechanical advantage used in dispensing material from a cartridge. While the devices disclosed in these patents provide easy dispensing of relatively high viscosity materials which are difficult to extrude, there is often a need to dispense low viscosity materials, such as fluids and gels, in a controlled manner. Generally, low viscosity materials are applied on a surface or large cavity, that is not parenterally. Often, dispensing of these relatively low viscosity materials, including fluids and gels, is done by brushing or dabbing with a hand held applicator. One such applicator system is disclosed in U.S. Pat. No. 5,660,273 entitled “Single Patient Dose Medicament Dispenser With Applicator” issuing to Discko, Jr. on Aug. 26, 1997. Therein disclosed is a tray having wells or depressions therein for holding a medicament or material and an applicator, such as a brush, for dispensing the medicament or material. Another technique for dispensing relatively small volumes of low viscosity material is by placing a quantity of the low viscosity material into a dropper type device which may be sealed, such as an ampule. One such device is disclosed in U.S. Pat. No. 5,320,257 entitled “Resilient Ampule With Articulating Linkage And Elongated Spout” issuing to Snedden on Jun. 14, 1994. Therein disclosed is an elongated ampule having a reservoir bulb on one end and an elongated spout on the other end with an articulating linkage or bellows therebetween. 
   While many of these prior devices have adequately dispensed material, there is a need for an improved and more convenient apparatus and method for dispensing low viscosity materials economically and in a controlled manner with a single dose system. 
   SUMMARY OF THE INVENTION 
   The present invention is a delivery system for controllably dispensing a low viscosity material, such as a liquid or a gel, in a single or unit dose. The ampule having a body with a sealed end and a dispensing end having a nozzle which has a removable seal. The ampule is made of a flexible collapsible material such as a pliable plastic. The material contained within the ampule is sealed and is of sufficient quantity for a single dose. A syringe has a structure to facilitate removal of the expended collapsed ampule. One embodiment of the invention has a syringe having a plunger adapted to controllably dispense the liquid or gel material contained within the ampule and is shaped or dimensioned to facilitating easy removal of the expended collapsed ampule. In another embodiment the syringe has a breach positioned to facilitate easy insertion and removal of the ampule. In another embodiment the syringe has multiple internal diameters to facilitate removal of the expended ampule. The ampule and syringe combination provides economical and controlled dispensing of a low viscosity liquid or gel in a unit dose. Any low viscosity material may be dispensed, but the present invention is particularly applicable to dispensing medical materials, including dental materials, such as adhesives, sealants, etches, or other material to be applied non parentally. 
   Accordingly, it is an object of the present invention to provide a unit dose dispensing system for low viscosity materials, such as liquids and gels, for both medical and industrial use. 
   It is another object of the present invention to provide controlled dispensing of relatively small volumes of low viscosity materials. 
   It is an advantage of the present invention that a unit measured dose of low viscosity material can be dispensed economically. 
   It is another advantage of the present invention that the collapsed expended ampule is easily removed from the barrel of a syringe. 
   It is yet another advantage of the present invention allows for controlled flow and placement of material without spurting and also improves visibility during dispensing. 
   It is a feature of one embodiment of the present invention that the end of a plunger is shaped so as to grasp the collapsed expended ampule, facilitating easy removal. 
   It is another feature of one embodiment of the present invention that a breach is positioned relative to the ampule, facilitating extrusion or dispensing of the low viscosity material. 
   It is yet another feature of one embodiment of the present invention that the internal diameters of the barrel facilitates dispensing of the material contained within the ampule and removal of a collapsed expended ampule. 
   These and other objects, advantages and features will become readily apparent in view of the following more detailed description. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of an ampule. 
       FIG. 2  is a plan view of the ampule illustrated in FIG.  1 . 
       FIG. 3  is a cross sectional view taken along line  3 — 3  in FIG.  2 . 
       FIG. 4  is a rear elevational view of the ampule illustrated in FIG.  1 . 
       FIG. 5  is a perspective view of a dispensing syringe. 
       FIGS. 6A-C  are partial cross sectional views illustrating operation of the present invention. 
       FIG. 7  is a partial section illustrating one embodiment of the present invention. 
       FIG. 8  is a partial cross section of another embodiment of the present invention illustrating the positional relationship of a breach. 
       FIG. 9  is a partial cross section of another embodiment of the present invention having opposing breaches. 
       FIG. 10  is plan view illustrating an embodiment of the present invention with a e. 
       FIGS. 11A-C  schematically illustrate a partial view of plunger ends of different embodiments of the present invention. 
       FIG. 12A  is a perspective view of another embodiment of an ampule of the present invention. 
       FIG. 12B  is a plan view of the ampule illustrated in FIG.  12 A. 
       FIG. 12C  is a cross section taken along lines  12 C— 12 C in FIG.  12 B. 
       FIG. 13A  is a side elevational view of another embodiment of an ampule of the present invention. 
       FIG. 13B  is a rear elevational view of the ampule illustrated in FIG.  13 A. 
       FIG. 13C  is a cross section taken along line  13 C— 13 C in FIG.  13 B. 
       FIG. 14A  is a side elevational view of another embodiment of an ampule of the present invention. 
       FIG. 14B  is a rear elevational view of the ampule illustrated in FIG.  14 A. 
       FIG. 14C  is a cross section taken along lines  14 C— 14 C in FIG.  14 B. 
       FIG. 15  is a side elevational view in partial section of a syringe having a mechanical advantage. 
       FIG. 16  is a perspective view illustrating another embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1  is a perspective view illustrating an ampule  10 . The ampule  10  may be made of any suitable collapsible or flexible material such as a plastic, including polypropylene, polyethylene, and other moldable plastics. The plastic may be selected from any type of material with suitable properties such that it does not react with the material contained therein or it does not change the properties of the material due to absorption of any component of the material. The ampule  10  has a body  12  with a hemispherical sealed end  14  and a dispensing end  16 . The dispensing end  16  has a nozzle or spout  18 . One end of the nozzle  18  is sealed with a seal  20  which may is removable, either by cutting off, breaking off, snapping off, or twisting off the seal  20 . Additionally, the nozzle  18  may be sealed with a plug or other equivalent seal. A low viscosity material such as a liquid, gel or paste is sealed within the ampule  10 . By low viscosity it is meant any material having a viscosity such that when expressed, extruded or forced from the ampule  10 , the flexible or pliable material of the ampule  10  will not unintentionally rupture. The viscosity of liquids, gels, or pastes may be such as to be able to be used in the capsule or ampule  10 . This would be dependent on the type of plastic and the mechanical advantage, if any, needed to express the material. 
     FIG. 2  is a plan view more clearly illustrating the ampule  10 .  FIG. 3  is a cross sectional view taken along lines  3 — 3  in  FIG. 3  illustrating material placed within the ampule  10 .  FIG. 4  is a rear elevational view more clearly illustrating the ampule  10 . 
   Referring to  FIGS. 2-4 , the body  12  of the ampule  10  is readily collapsible such that the low viscosity material  22  can be dispensed through nozzle  18  when seal  20  is removed. The seal  20  may be any convenient seal for sealing the end of the nozzle  18 . The nozzle  18  preferably is elongated and at an angle such that placement of the material  22  is facilitated. The nozzle  18  is sufficiently flexible such that it could be moved into an axial position relative to the body portion  12 . 
     FIG. 5  is a perspective view illustrating a syringe used to dispense the material in the ampule  10  illustrated in  FIGS. 1-4 . The use of a dispenser syringe  24  greatly facilitates the ease and control within which the material within an ampule may be dispensed. The dispenser syringe  24  comprises a plunger  26  adapted to be received by a barrel  28  through opening  32 . Adjacent opening  32  is a flange  30 . The plunger  26  has a plunger tip  34  and a reduced diameter portion  36 . A shoulder  40  is formed between the reduced diameter portion  36  and the plunger tip  34 . The plunger tip  34  may be hemispherical. A land  35  may be positioned between the shoulder  40  and the hemispherical plunger tip  34 . Additionally, on the plunger  26  is a groove  38 . The groove  38  may be used to hold an O-ring to provide a seal or friction between the inner diameter of the barrel  28  and the plunger  26 . An O-ring type seal may also be molded into or formed integrally from the material of the plunger  26 . A pad  42  is placed on one end of the plunger  26  to facilitate dispensing. 
     FIGS. 6A-C  illustrate the operation of the present invention and ease in which a material can be dispensed.  FIG. 6A  illustrates an ampule being loaded into the opening  32  in the rear end of the barrel  28 . Nozzle  18  is flexible and easily moved into an axial position in a direction of arrow  44  illustrated in phantom at  18 ′. The body portion  12  should have a diameter nearly equal to or slightly less than the internal diameter of the barrel  28 . The nozzle  18  is directed by inclined surface  37  through an opening  33 . 
     FIG. 6B  illustrates the insertion of the plunger  26  into the barrel  28  and advancing the plunger in the direction of arrow  46 . An O-ring  48  may be placed in the groove  38  within the plunger  26  so as to provide a friction resistance or a seal. Upon removal of the seal  20  on the end of the nozzle  18 , and the advancing of the plunger  26 , the plunger tip  34 , being hemispherical, collapses the hemispherical end  14  of the ampule causing the body portion  12  to collapse and roll over the plunger end  34  and the land  35 . The relatively low viscosity material is thereby dispensed from the body  12  of the ampule. The dispensing of the material is precisely controlled. Additionally, the syringe dispenser  24  helps to extend the reach and placement of material, especially within difficult to reach areas, such as the mouth in dental applications. The syringe dispenser  24  also greatly improves visibility within small openings, such as the mouth. 
     FIG. 6C  illustrates the dispensing of a material  22  from the nozzle  18  and the collapse of the body portion  12 . The diameter of the land  35  on the plunger end is such that there is a gap between the internal diameter of the barrel  28  permitting a portion  50  of the collapsed body portion  12  of the ampule to fit between the internal diameter of the barrel  28  and the land portion  35  of the plunger end. This gap should be between one and two times the wall thickness of the ampule  10 . The material of the collapsed ampule  50  is forced through this gap and is caught by the shoulder  40  between the land  35  and the reduced diameter  36  of the plunger  26 . Accordingly, after dispensing of the material contained within the ampule and body portion  12 , the expended collapsed ampule is easily removed by withdrawing the plunger  26 . The mushroom like shape of the end of the plunger and the shoulder  40  in combination with the gap formed between the diameter of the land  35  and the reduced diameter  36  caused the plunger end to grab and hold the collapsed material of the ampule  10  and body portion  12  such that it is attached to the end of the plunger  26  and therefore is withdrawn with the plunger  26 . This facilitates easy removal from the barrel  28  of the expended collapsed ampule. 
     FIG. 7  is a partial cross section of another embodiment of the present invention. In this embodiment, a portion of a dispensing syringe is illustrated having a barrel  128  with different internal diameters. The barrel  128  has a larger first diameter d 1  and a smaller second diameter substantially equal to the diameter d 2  of the body portion  12  of the ampule  10 . The reduced diameter portion of the barrel  128  is adjacent the opening  133  through which the nozzle  18  extends and has an axial length L 1  equal to a substantial portion of the axial length L 2  of the body  12  of the ampule  10 . The transition  158  between the two diameters in the barrel  128  may be a curve or a ramp. The transition may also be a step. The rear end portion of the ampule  10  extended into the larger internal diameter portion of the barrel  128  facilitates the rear hemispherical end  14  to collapse and the initiation of rolling over the plunger end such that the dispensing of the material contained within the ampule  10  is more controlled, and the ampule body  12  collapses evenly and uniformly as the plunger advances. Additionally, the larger diameter d 1  greatly aids in the material of the body  12  to be forced around the outside of the plunger end as the plunger advances into the smaller diameter portion of the barrel  128 . Accordingly, it is more assured that the expended collapsed ampule will attach itself to the end of the plunger so that when the plunger is withdrawn, the expended collapsed ampule is pulled out with the plunger. The larger diameter d 1  also facilitates collapsing of the hemispherical end portion  14  of the ampule  12  preventing initial spurting of material when being dispensed. Additionally, the barrel  128  has an angled surface or bevel  152  adjacent opening  133  to allow easier removal of the ampule  10 . 
     FIG. 8  illustrates another embodiment of the present invention. The dispenser syringe  224  of this embodiment has a breach  227  within a side wall of the barrel  226 . The breach  227  has an axial length sufficient to permit insertion of the ampule  10 . The syringe dispenser  224  may also have bevel or angled surface  252  adjacent the opening  233  through which the nozzle  18  extends. This facilitates insertion and removal of the nozzle portion  18  of the ampule  10 . The breach  227  in a side wall of the barrel  226  should be positioned close enough to the opening  233  such that a portion of the body  12  of ampule  10  extends beyond the forward end of the breach  227 . This axial distance is illustrated as L 3 . The distance L 3  is preferably substantially equal to a diameter of the body portion  12  of the ampule  10 . The extension of the ampule  10  under or in the breach  227  facilitates collapse of the hemispherical end  14  prior to being confined by the internal diameter of the barrel  226 . This has been discovered to greatly facilitate the controlled release of the material within the ampule  10  so as to prevent spurting or jerky dispensing of the material within the ampule  10  upon initial dispensing. This embodiment provides for a much more consistent and even flow during the entire dispensing sequence. This is often critical in procedures involving dentistry and placement of low viscosity materials in a patients mouth. 
     FIG. 9  illustrates another embodiment of a syringe dispenser  324 . In this embodiment, opposing breaches  327  and  327 ′ are formed within the barrel  236 . The opposing breaches facilitate insertion and removal of the ampule  10 . The ampule  10  can easily be inserted and removed with the double opposing breach configuration. The thumb and forefinger can be used to grasp the ampule on either side through the breaches and inserted into the front portion of the barrel  326  prior to advancing the plunger  26 . Likewise, upon removal, the double breach permits easy grasping of the expended ampule  10 . This embodiment also has a beveled or angled surface  352  adjacent opening  333  through which the nozzle  18  of the ampule  10  extends. Similar to the prior embodiments, the hemispherical plunger end  34  forces a portion of the collapsed ampule  50  between the gap in the land  50  and the internal diameter of the barrel  326  such that the expended collapsed ampule end  50  is caught or hooked onto the shoulder  40 . This permits the ampule  10  to be withdrawn from the front of the barrel after being expended and when withdrawing the plunger  26 . The breaches illustrated in FIG.  8  and  FIG. 9  make possible the insertion and removal of an ampule without the necessity of removing the plunger  26 . 
     FIG. 10  is a top view illustrating the breach  327  and the withdrawal of the plunger  326  drawing back the body portion  12  of ampule  10 . Additionally, illustrated is a detent  349  which co-acts with the O-ring  48  to prevent the plunger  26  from falling out of the end of the barrel  326  unintentionally. 
     FIGS. 11A-C  schematically illustrate portions of plunger ends which may be utilized in practicing the present invention.  FIG. 11A  illustrates the front portion of a plunger  126  having a groove  135  therein and a hemispherical front portion  134 . A shoulder  140  is formed by the groove  135 . The tip of the shoulder  140  may extend slightly above the surface of the plunger  126  so as when advanced the expended collapsed ampule body portion is hooked by the raised shoulder  140  facilitating removal.  FIG. 11B  illustrates a plunger  226  having a front portion  236  with a reduced diameter. In this embodiment, the reduced embodiment  236  has a diameter slightly smaller than a front opening in the barrel such that after extruding of the materials in the ampule with a relatively low first force on the plunger  226 , the plunger  26  may be advanced with a substantially greater force so as to push the expended collapsed ampule out of the front opening of the barrel with the reduced diameter portion  236 . The difference between the opening in the barrel and the reduced diameter portion  236  should be greater than twice the thickness of the plastic material from which the ampule is made.  FIG. 11C  illustrates another embodiment of a plunger  336 . Plunger  336  has a front end having a land  335  and an adjacent groove  336  such that an inclined shoulder  340  is formed. The inclined shoulder  340  aids in grasping the expended collapsed ampule such that it can be withdrawn or removed when removing the plunger  326 . While  FIGS. 11A-C  illustrate different embodiments of a plunger, it should be readily appreciated that other embodiments or plunger designs may easily be achieved based upon the teachings of the present invention. Other equivalent designs may be contemplated that serve the function of grasping the expended collapsed ampule so that it could be withdrawn from a barrel. In another embodiment, the plunger may be smooth. 
     FIGS. 12A-C  illustrate another embodiment of an ampule  110 . In this embodiment, a concave hemispherical sealed end  114  is formed. The concave hemispherical sealed end  114  facilitates dispensing of the material and permits a more even steady flow upon initial dispensing of the material and prevents the possibility of spurting material. Uneven flow or spurting may be more likely in the convex hemispherical sealed end embodiment illustrated in  FIGS. 1-4 . The use a dispensing syringe of the embodiment illustrated in  FIG. 7  having a double inner diameter reduces the need for the concave hemispherical sealed end  114  of the ampule  110 .  FIG. 12A  illustrates an ampule  110  having a body portion  112  and a nozzle  118 . Nozzle  118  is sealed by seal  120 . It should be appreciated that seal  120  need not take the form as illustrated, but may simply be a small spherical end to the nozzle  118 , or any other equivalent seal.  FIG. 12B  is a plan view more clearly illustrating the ampule  110 .  FIG. 12C  is a cross section taken along line  12 C— 12 C in FIG.  12 B and more clearly illustrates the concave hemispherical sealed end  114  of this embodiment of the present invention. Material  122  is contained within the ampule  110 . 
     FIGS. 13A-C  illustrate yet another embodiment of the present invention. Ampule  210  comprises a bellows body portion  212  having a front collar  213  at one end and a sealed end  214  at the other. The sealed end  214  also has a recess  214 ′ therein. The recess  214 ′ is coaxial with the body portion  212  and is sized to mate with the end of a plunger, preventing the sealed end  214  from deviating axially during compression of the bellows body portion  212  during dispensing the material  222  contained therein out of nozzle  218 . 
     FIGS. 14A-C  illustrate another embodiment of the present invention. Ampule  310  comprises a curved body portion  312  having a sealed end with an attached piston  314 . Piston  314  has a concave portion  314 ′. The body portion  312  may initially be sealed at the dispensing end and easily cut, pierced, broken off, or snapped off to dispense the material  322  contained therein. The attached piston  314  has an inclined surface or is conically shaped such that upon advancing, the walls of the body portion  312  are rolled along the surface of the plug or piston  314 . This assures that the walls of the body portion  312  are uniformly and evenly folded over upon themselves, preventing spurting or jerky dispensing of the material  322  contained therein. Preferably, the axial length of the piston  314  is approximately equal to the greatest lateral dimension of the body portion  312 . 
     FIG. 15  illustrates an embodiment of the present invention utilizing a syringe having a mechanical advantage. A barrel  428  has a handle  430  thereon. Lever  442  is pivotally connected to the handle  430  and has a cam surface that advances the plunger  426 . The plunger  426  may have a spring  454  on either end thereof so as to bias the plunger away from the dispensing end. The plunger  426  also has a reduced diameter section  436  sized to mate with the rear of an ampule  210 . The ampule  210  is placed through a breach adjacent the end of the barrel  428 . A shoulder  456  on the end of the barrel  428  holds the collar  213  of the ampule  210 . The rear end  214  of the ampule  210  is advanced by the reduced diameter portion  436  of the plunger  426 . The bellows body portion  212  collapses axially. The collar  213  in combination with the sealed rear end  214  permit the breach to be placed adjacent the front of the barrel so as to greatly facilitate insertion and removal of the ampule  210  in this embodiment. The bellows body  312  permits the use of a more rigid plastic material which facilitates the dispensing of materials that may have slightly more viscosity than a liquid or a gel. The recess  214 ′ mating with the reduced diameter end  436  of the plunger  426  helps to maintain axial alignment of the bellows body portion  212  of the ampule  210 . 
     FIG. 16  is a perspective view illustrating another embodiment of the present invention having a barrel  528  with a breach  527  therein and a shoulder  556  adapted to mate with a collar  213  on ampule  212 . The syringe dispenser  526  does not have a mechanical advantage. A plunger  26  having a pad  42  thereon is advanced forward striking the sealed rear end  214  compressing the bellows body portion  212  of the ampule  210  dispensing a material from nozzle  218 . 
   Accordingly, it should be appreciated from the above description that the present invention has several embodiments that greatly facilitate the dispensing of low viscosity materials including liquids and gels in a controlled manner. The present invention has the benefit of utilizing ampules that may be relatively inexpensively manufactured providing a unit dose or a predetermined dose of material that can be easily applied in a controlled, even manner without spurting or jerkiness in motion. This permits very fine control in the dispensing of a liquid or a gel without the need of a separate applicator, such as a brush or swab. 
   While several embodiments of the present invention have been illustrated and described, it will be obvious to those skilled in the art to apply the teachings of the present invention to their respective arts. Additionally, although the preferred embodiments have been illustrated and described, it will be obvious to those skilled in the art that various modifications may be made without departing from the spirit and scope of this invention.

Technology Classification (CPC): 0