Abstract:
A syringe system for delivering a dental material comprises a barrel configured for containing the material, a plunger configured for extruding the material, a divider configured for sectionalizing the material while it is being extruded, and a tool configured for detachment of the divider. The divider comprises at least one cutting plate that is affixed to the barrel and the tool comprises at least one recess configured for engaging the at least one cutting plate when the tool is inserted within the barrel, such as in a press fit arrangement. When the tool is axially rotated relative to the barrel, the at least one cutting plate can be effectively sheared away from the barrel. The tool may comprise a cap that is configured for sealably closing the syringe or a tool separate from the syringe.

Description:
BACKGROUND OF THE INVENTION 
     1. The Field of the Invention 
     The present invention generally relates to syringe systems used for storing and dispensing pliable materials, and, more specifically, to dental syringe systems capable of providing controllable doses of the pliable materials. 
     2. The Relevant Technology 
     In the dental industry, it is common for dental composites and other restoration materials to be stored and dispensed from syringes. Syringes are useful because they are compact and they enable the dental practitioner to generally control the quantity of material that is expelled out of the syringe at any given time. Sometimes, however, the barrel of the syringe is too wide for enabling sufficient control over the expulsion of the composite material out of the syringe. In particular, when the composite material is extruded out of the syringe barrel, it is sometimes difficult for the dental practitioner to partition and remove a desired dosage of the composite from the barrel. 
     One device that has been developed to overcome the aforementioned problems is a syringe with a divider located at the tip. The divider comprises cutting plates that sectionalize the composite material while it is extruded. The unique divider configuration, known as the QUADRASPENSE®, may comprise various combinations and configurations of cutting plates for controlling the shape and size of the sectionalized material as it is expressed. The cutting plates are also useful for accommodating the removal of the sectionalized material once it is expressed out of the syringe barrel. For example, a spatula or another scrapping tool can be pressed through the sectionalized material and against the cutting plates, thereby enabling the scrapping tool to scrape away and easily remove a desired quantity of material. Syringes having this design are described more fully in U.S. Pat. No. 5,387,103, issued to Fischer, and are presently sold by UTRADENT PRODUCTS, INC. of South Jordan, Utah. 
     One limitation of syringes with cutting plates, however, is that the cutting plates are securely affixed to the barrels of the syringe, which inhibits the dental practitioner from removing the cutting plates, even when the cutting plates are no longer needed or desired. The cutting plates may not be desired, for instance, when large amounts of composite are required during the dental procedure. The cutting plates are also not desired when most of the composite material is already expelled out of the syringe and the cutting plates obstruct the plunger from expelling the residual portions of the composite material from the barrel. 
     Accordingly, it is sometimes desirable to remove the cutting plates from the syringe. However, as mentioned above, the cutting plates are typically affixed to the barrel with a secure bond that is created at the time of manufacture, such as during an injection molding process. There is currently no tool that is specifically designed for removing the cutting plates from the QUADRASPENSE® type syringe systems. Therefore the dental practitioner must currently use pliers, a knife, or another device to separate the cutting plates from the barrel of the syringe. It will be appreciated that this is inconvenient, in part, because it can be difficult to find pliers or a knife that is suitably sized for being inserted within the barrel in a manner that is sufficient for cutting or pulling the cutting plates cleanly, away from the sides of the barrel. Furthermore, the use of a cutting device to remove the cutting plates can be risky, inasmuch as the cutting device can slip and cut the dental practitioner. 
     Accordingly, in view of the foregoing, there is currently a need in the art for improved syringe systems incorporating tools that are configured for facilitating the removal of the cutting plates from the syringe systems and in a manner that does not pose a risk of injury. 
     SUMMARY OF PRESENTLY PREFERRED EMBODIMENTS 
     Briefly summarized, presently preferred embodiments of the present invention are directed to improved syringe systems that incorporate dividers and tools that are specifically designed for controllably removing the dividers from the syringe systems when desired. 
     According to one presently preferred embodiment, the syringe systems of the invention comprise a syringe that is configured for expressing dental material from a syringe barrel incorporating a divider configured for sectionalizing the material as it is expressed from the barrel. The syringe systems also comprise a shearing tool configured for removing the divider from the barrel when it is no longer needed or desired. 
     The divider comprises at least one cutting plate that is securely affixed to the barrel at the outlet end of the barrel. As the material is expressed out of the barrel it is partitioned by the cutting plate and extruded in sectionalized portions. The divider can be removed when desired by inserting the tool within or next to the outlet end of the barrel and engaging the cutting plate with a shearing force. The shearing tool is configured in size and shape to be inserted within the outlet end of the barrel and to engage the at least one cutting plate. Once the shearing tool is appropriately positioned relative to the barrel so as to engage the cutting plate, as described, the tool is axially rotated relative to the barrel, e.g., about the central axis of the barrel. Axial rotation generates forces that are applied by the shearing tool at the cutting plates, thereby shearing the cutting plates away from the barrel. The shearing tool can be rotated by hand, with the fingers, or with the assistance of another tool, such as pliers. Once the cutting plates have been separated from the barrel then they can easily be removed from the barrel by the shearing tool, which may engage the cutting plates in a press fit arrangement. 
     According to the invention, the shearing tool may comprise a cap that is configured for sealably closing the syringe during nonuse. The shearing tool may also comprise a that is completely separate from the syringe. 
     One advantage of the invention is that a dental practitioner can utilize the benefits of syringe incorporating a divider until the divider is no longer desired, such as, for example, when the material within the syringe is almost entirely exhausted and the plunger of the syringe is inhibited by the divider from extruding the residual portions of the material. The invention then enables the practitioner to easily remove the undesired divider when it is no longer needed. The tool may be specifically sized so as to be inserted within the outlet end of the barrel and about the divider. In this way, the divider can be removed cleanly, with minimal effort, and without the risks posed by sharp cutting devices. 
     These and other benefits, advantages and features of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of the invention as set forth hereinafter. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In order that the manner in which the above recited and other benefits, advantages and features of the invention are obtained, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments thereof, which are illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments of the invention and are not therefore to be considered limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which: 
     FIG. 1 illustrates a perspective view of one embodiment of the syringe system of the invention that includes a syringe having a divider and a shearing tool configured for shearing the divider from the syringe; 
     FIG. 2 illustrates a perspective view of the syringe system shown in FIG. 1, in which the shearing tool is positioned in an initial engagement position with the divider; 
     FIG. 3 illustrates a perspective view of the syringe system shown in FIG. 2, in which the divider is completely engaged within recesses formed in the shearing tool; 
     FIG. 4 illustrates a perspective view of the syringe system shown in FIG. 3, in which the shearing tool is rotated and the divider is sheared away from the barrel of the syringe; 
     FIG. 5 illustrates a perspective view of the syringe system shown in FIG. 4, in which the shearing tool and the divider have been removed from the barrel; 
     FIG. 6 illustrates a perspective view of one embodiment of the syringe system of the invention that includes a syringe having a divider and a hexagonally shaped head; 
     FIG. 7 illustrates a perspective view of one embodiment of the syringe system of invention that includes a syringe having a divider and a cap for the syringe that is configured for shearing the divider from the syringe; and 
     FIG. 8 illustrates a perspective view of one embodiment of the syringe system of the invention that includes a syringe having a divider composed of a single cutting plate and a shearing tool configured for shearing the divider from the syringe. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A detailed description of the syringe system of the invention will now be provided with specific reference to figures illustrating preferred embodiments of the invention. It will be appreciated that like structures will be provided with like reference designations. 
     To provide assistance in construing the scope of the invention, definitions to terms used throughout the application will now be provided. The term “shear” as used herein generally refers to separating two items that are connected together with a force that is sufficient to break any bonds of affixation between the two items and which generally causes the two items to move in opposite directions with respect to each other without causing a change in the general shape of either item. 
     The term “pliable material” as used herein generally refers to a material that can be easily deformed or shaped. The term “pliable material” can be construed to include any material that that has a very high degree of viscosity, characterized by a soft clay or paste type consistency, yet is deformable enough to be applied through a syringe. According to one embodiment, the term “pliable material” refers specifically to dental composite materials used for dental applications. 
     Reference is first made to FIG. 1, which illustrates one exemplary embodiment of the syringe system  10  of the invention. As shown, the syringe system  10  generally includes a syringe  12  configured to express a pliable material during a dental procedure and a shearing tool  14  configured for removing a divider that is attached to the syringe  12 . The syringe  12  and the shearing tool  14  are each described below. 
     The syringe  12  includes a barrel  16  extending from an inlet end  18  to an outlet end  20 . The barrel  16  is specifically configured to hold a pliable material, such as a dental composite material (not shown). The dental composite material is contained within the barrel  16  and is expelled from the outlet end  20  of the barrel  16  when a head  21  of a plunger  22  is advanced through the barrel  16  from the inlet end  18  to the outlet end  20 . 
     According to one embodiment, the plunger  22  is threaded and engages a threaded coupling  24  connected with the inlet end  18  of the barrel  16 . As the plunger  22  is rotated in a clockwise direction, the plunger  22  is advanced by the threaded coupling  24  through the barrel  16  towards the outlet end  20  of the barrel  16 . When the plunger  22  is rotated in a counterclockwise direction, the plunger  22  is forced by the threaded coupling  24  to retract towards the inlet end  18  of the barrel  16 . According to another embodiment, the plunger  22  is forced back and forth within the barrel  16  as the plunger  22  is rotated in directions opposite from those mentioned above. According to yet another embodiment, the plunger  22  does not include a threaded coupling  24 , rather the plunger  22  is forced through the barrel  16  simply by applying an appropriate force to the back of the plunger  22 . 
     As mentioned above, pliable material within the barrel  16  is pressed towards and through the outlet end  20  of the barrel  16  by the force of the plunger  22 . As the pliable material is pressed through the outlet end  20  of the barrel  16  it is sectionalized by cutting plates  30  of a divider  32  that is attached at the outlet end  20  of the barrel  16 . The divider  32  may include any number of cutting plates  30  configured to sectionalize the material into any number of desired sections having any desired proportions. According to one embodiment, the divider  32  includes four cutting plates  30  configured for dividing the material into four equally proportioned sections. The four cutting plates may be considered to be two bisecting cutting plates. This embodiment is illustrated in FIGS. 1-7. According to another embodiment, the divider may consist of only a single cutting plate configured to divide the material into two equally proportioned sections when it is expelled out of the barrel  16 . 
     The dividers  32  are generally useful for facilitating removal of the material from the syringe  12 . In particular, the dividers  32  can be utilized as a scraping surface against which a scraping tool can bias while scraping away portions of the pliable material from the syringe  12 . Dividers and scraping tools, which are used to facilitate the removal of a material from a syringe, are well known by those skilled in the art. 
     Although dividers are generally useful for their intended purpose, they are sometimes undesirable. In particular, once the plunger  22  is completely inserted within the barrel  16  so that it is biased against the divider  32  it can no longer expel material out of the syringe. The divider  32  effectively prevents the plunger  22  from pushing the residual portions of the material out of the syringe. Accordingly, in order to remove the residual portions of the material from the syringe  12 , it may be necessary to scrape around the internal circumference of the barrel  16  and between the cutting plates  30  of the divider  32  with a scraping tool. This, however, can be difficult because the divider  32  hinders scraping tools from being manipulated inside of the barrel  16 . Accordingly, it will be appreciated that it can sometimes be useful to remove the divider  32  from the barrel  16  so that the plunger  22  can push the remaining portions of the material out of the barrel  16 . 
     One method for removing the divider  32  from the barrel  16  is to use a pulling device, such as a pair of pliers to grab and pull the divider  32  away from the barrel  16 . This method, however, has proven to be awkward and inadequate. The bond between the divider  32  and the barrel  16  is strong enough that it is often necessary to apply a great amount of force to the divider  32  before it can be detached. However, because pliers are not specifically designed to be inserted within a small barrel  16 , while at the same time being opened to grab the divider  32 , they can often only be used to grab a hold of small portions of the divider  32  that protrude out of the barrel  16 . Accordingly, pliers, as well as other tools, are prone to slip off of the divider  32  while detaching the divider  32  from the barrel  16 . Furthermore, even when the pliers do not slip off of the divider  32 , they generally cause the forces applied to the divider  32  be distributed unevenly which can cause the divider  32  to be stretched and torn or ripped abnormally away from the barrel, with small portions of the divider  32  remaining attached to the barrel  16 . The stretching and tearing of the divider is largely a function of not being able to apply the forces directly at the locations where the divider  32  is attached to the barrel  16 . 
     Another method for removing the divider  32  is to use a cutting device, such as a knife to cut the divider  32  from the barrel  16 . Cutting devices, however, create an unnecessary element of risk to the person removing the divider  32 . Furthermore, because cutting devices are not typically configured in size and shape for being inserted within a small syringe barrel  16 , they also are generally unable to cleanly separate the divider  32  from the barrel  16 . It will be appreciated that any portions of the divider  32  that are not entirely removed from the barrel  16  can obstruct passage of the plunger  22  through the barrel  16 , effectively preventing the plunger  22  from expelling the remaining portions of the material. 
     The present invention overcomes the problems mentioned above by providing a shearing tool  14  that is specifically configured in size and shape to be inserted within or next to the barrel  16  of the syringe  12  and to apply a shearing force directly at the locations where the divider  32  is connected to the barrel  16 . According to one embodiment, the shearing tool  14  is comprised of plastic. Plastic is a good material because it is relatively inexpensive. It will be appreciated, however, that other materials can also be used, such as for example ceramics and metals. Ceramics and metals are also good materials because they are relatively rigid which can be useful when shearing the divider  32  from the barrel  16 . 
     Turning now to FIG. 2, phantom imaging is used to show how the divider  32  is attached to the inside of the barrel  16 . According to one embodiment, the divider  32  is molded together with the barrel  16  at the time of manufacture. The divider  32  can also be attached to the barrel  16  by any other suitable means, including, but not limited to, press fitting, adhesive bonding, and the like. In order to cleanly break the bond between the divider  32  and the barrel  16  it is desirable to apply a shearing force at the locations where the divider  32  is attached to the barrel  16 . This is possible, according to the present invention by using a shearing tool  14  that is configured in size and shape to engage the cutting plates  30  of the divider  32  at the locations adjacent to where the cutting plates  30  are affixed or otherwise connected with the barrel  10 . 
     As shown in FIG. 2, the shearing tool  14  of the invention comprises a stem  40  that is configured into the general shape of the barrel  16  and includes recesses  42  that are configured to receive and engage the cutting plates  30  of the divider  32  when the stem  40  is inserted within the outlet end  20  of the barrel  16 . It will be appreciated that as the stem is inserted within barrel  16  that the stem  40  will push any material back into the barrel  16 . To avoid any undesired compressive forces, the plunger can be retracted prior to inserting the stem  40  into the barrel  16 . 
     FIG. 3 illustrates a partial cross-sectional view of the syringe system  10  of the invention in which the shearing tool  14  has been inserted into the barrel  16  and in which the cutting plates  30  of the divider  32  have been fully received within the recesses  42  of the shearing tool  14 . As shown, the shearing tool  14  may also include a lip  50  for gauging how far the stem is to be inserted within the barrel  16 . The lip  50  can be useful, for example, for ensuring that the cutting plates  32  are entirely engaged within the recesses  42  of the shearing tool  14 . In this way, the shearing forces can be applied evenly along the cutting plates  30  so as to facilitate shearing the cutting plates  32  cleanly away from the barrel  16 . It will be appreciated that according to certain embodiments the stem  40  of the shearing tool  14  may be inserted beyond the cutting plates  30 . 
     Turning now to FIG. 4, it is shown how the shearing tool  14  can be used to shear the divider  32  away from the barrel  16 . As shown, the divider  32  is shorn away from the barrel  16  when the shearing tool  14  is axially rotated about the central axis  60  of the barrel  16  within or next to the outlet end  20  of the barrel  16 . A phantom image  70  is provided to illustrate the previous location of the divider  32  before the shearing tool  14  was rotated. It will be appreciated that the divider  32  can be separated from the barrel  16  by rotating the shearing tool  14  in either a clockwise or a counterclockwise direction with respect to the barrel  16 . 
     According to one embodiment the stem  40  of the shearing tool  14  is configured in size and shape to fit within the barrel  16  so that the stem  40  engages the internal surfaces of the barrel  14 . This enables the shearing tool to apply shearing forces along the entire length of the cutting plates  30  where they engage the barrel  16 , so as to cleanly shear the cutting plates  30  away from the barrel  16 . It will be appreciated that this is an improvement over the prior art. 
     According to other embodiments the stem  40  of the shearing tool  14  is sized smaller than the barrel  16  so that the stem  40  does not engage the interior surfaces of the barrel  16 . According to these embodiments, the stem  40  applies shearing forces to the cutting plates adjacent to the locations where the cutting plates  30  are affixed to the barrel  16 . It will be appreciated that this is also an improvement over the prior art because the stem  40  of the shearing tool is still able to apply forces uniformly along the entire length of the cutting plates  30 , thereby minimizing the likelihood that the divider will stretch and tear abnormally away from the barrel. 
     Once the bond between the divider  32  and the barrel  16  is broken, the shearing tool  14  and the divider  32  can be removed from the barrel  16 . This may occur in two steps or in a single step. In particular, the shearing tool  14  can first be removed and then the divider  32  can be removed, or alternatively, the divider  32  can be removed simultaneously with the shearing tool  14 . According to one embodiment, as shown in FIG. 5, the divider  32  engages the recesses  42  of the shearing tool  14  in a press fit arrangement so that when the shearing tool  14  is removed from the barrel  16  the divider  32  is pulled out from the barrel  16  by the shearing tool  14 . This embodiment is also useful for ensuring that the material within the syringe  12  is cleanly scraped off of the cutting plates  30  and into the barrel  16  when the shearing tool  14  is first inserted into the barrel  16 . 
     FIG. 6 illustrates one embodiment of the invention in which the head  80  of the shearing tool  114  is configured in the shape of hexagon. This embodiment is useful for enabling a wrench or other tool to grip the head  80  to facilitate the rotation of the shearing tool  14  within the barrel  16 . The flattened shape of the head  90  in FIGS. 1-5 is useful when using fingers to rotate the shearing tool  14 . To facilitate gripping of the head  90 , the head  90  may be textured. As shown in FIGS. 1-5, the head of the shearing tool  14  may also include a hole  92  configured for connecting the shearing tool onto a chain so that the shearing tool is not easily misplaced. 
     According to another embodiment, as shown in FIG. 7, the shearing tool  214  may also comprise the cap  220  to the syringe  12 . This embodiment is particularly useful for ensuring that the shearing tool  214  is not misplaced or lost during nonuse. As shown, the cap  220  is configured with a cylindrical recess  222  configured to receive the outlet end  20  of the barrel  16 . When the cap  220  engages the outlet end  20  of the barrel  16 , the barrel  16  is sealed closed so that any material within the barrel  16  can be preserved during periods of nonuse. The cap  220  can also operate as a shearing tool  214  to separate and remove the divider  32  from the barrel  16  when the divider  32  is no longer needed or desired. In particular, the cap  220  further includes a stem  240  configured to engage the divider  32 . The cap  220  can remove the divider  32  from the barrel  16  by rotating the cap  220  with the stem  240  of the cap  220  inserted within the outlet end  20  of the barrel  16 , as generally described above. 
     FIG. 8 illustrates one alternative embodiment of the invention in which the syringe  312  includes a divider  332  attached to the inside of barrel  316  and having only a single cutting plate  330  and in which the shearing tool  314  includes a corresponding recess  342  configured to engage the cutting plate  330 . It will be appreciated, however, that the shearing tool  314  may include any number of recesses configured for engaging any number of cutting plates and will still be operational to engage and remove the cutting plate  330  shown. 
     In summary, the syringe systems of the invention generally include a syringe having a divider and a tool configured for removing the divider from the syringe. The syringe systems of the invention are an improvement over the prior art for at least providing a means for effectively removing the divider from the syringe. 
     It will be appreciated that the present claimed invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative, not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.