Disposable Mixing Syringe

Abstract

A disposable mixing syringe is described. It comprises a barrel containing a removable centerboard dividing it into two compartments each for receiving one component of a mixture to be formed and terminating in a small orifice. The opposite barrel end is open and adapted to receive a slotted cup, through the slot of which passes an extension of the centerboard. Removing the centerboard allows mixture of the components by inserting a mixing tool, after which a suitable plunger is provided to expel the mixed contents through the orifice.

Description

This invention relates to a combination mixing syringe and disposable dispensing device especially adapted for providing mixtures of constituents having roughly equal proportions.

The invention is especially useful for mixing heavy or highly viscous materials. In one instance, to make epoxy type cements, one usually mixes equal proportions of a highly viscous resin and a highly viscous hardener or catalyst. After thorough mixing, the cement is ready to be applied to the articles to be joined. For use in making dental models, the epoxy has to be introduced to an impression. Centrifuging is necessary to ensure thorough contact because of the high viscosity. Thorough mixing of correct proportions of the epoxy constituents is not easily accomplished following the prior art, because of the difficulty of measuring out equal proportions of the heavy liquids from larger supplies and of mixing same. Moreover, centrifuging causes distortion of the model. In another instance involving a known dental impression technique, a rubber type impression material is formed by mixing equal proportions of a suitable rubber-type resin and a suitable catalyst and the mixture dispensed into a tray which is pressed onto the patient's jaw to form an impression of the teeth and gum. Particularly in the latter case, a predetermined amount of mixture is required to fill the tray. Present techniques for accomplishing the latter are cumbersome and time consuming because they place on the dental practitioner the burden of measuring equal proportions of the constituents taken individually from large tubes, and then completely mixing them on a slab, after which the mixture is transferred by hand directly to the tray. In an alternate method, the mixture is placed in a syringe and then extruded onto the patient's teeth. In the latter case, difficulties are encountered in transferring the highly viscous paste to the syringe, much waste occurs, and it is generally a messy and cumbersome procedure.

The main object of the invention is a device in which the correct proportions of a two-component mixture are pre-established though maintained separately, and by which they can be readily mixed, and the mixture then readily applied in an appropriate manner to an object to be coated.

This and other objects and advantages of the invention as will appear hereinafter are achieved, in accordance with the invention, by a disposable syringe having at one end an orifice through which the mixture may be expelled and having its opposite end open. A removable centerboard extends down the center of the syringe in engagement with the syringe walls, forming two adjacent, side-by-side compartments. One each of the mixture constituents is loaded into each of the compartments, where they are stored maintained separate from one another by the centerboard. The centerboard extends up above the syringe open end, which is then closed off by disposing a closure member in the opening and containing a slot for accommodating the centerboard extension. The closure which may be a foil not only serves to close off the syringe but also acts to wipe off the centerboard during its removal when the mixture is to be formed. A mixing tool is then inserted through the open end to mix the constituents together within the syringe, and after removal of the mixing tool a suitable plunger is inserted in the open end to expel the mixture through the orifice.

A further feature of the invention is the provision of one or more small projections or protuberances at the bottom of the centerboard which function to engage and cause lifting out and removal of the foil closure simultaneously with removal of the centerboard.

A further feature is construction of the foil in the shape of a cup which seats in the open barrel end. This construction not only simplifies assembly, but also allows with a modified centerboard retention of the foil during the mixing operation.

Among the advantages of the novel device of the invention are low-cost manufacture, pre-measured proportions of the ingredients ensuring the optimum mixture composition, rapid and intimate mixing of the constituents, disposability due to low cost, and minimum time expenditure by the user.

Several exemplary embodiments of the invention will now be described in greater detail with reference to the accompanying drawing, wherein:

FIG. 1 is a cross-sectional, elevational view of one form of combination syringe and mixing device of the invention;

FIG. 2 is a top view of the device shown in FIG. 1;

FIGS. 3-5 are cross-sections of the device of FIG. 1 showing how it is used;

FIGS. 6 and 7 are cross-sectional views of a modification.

One form of the invention is shown in cross-section in FIG. 1. It comprises a disposable syringe 5 comprising a generally cylindrical barrel 6 tapering down at its bottom end to a nozzle 7 having an orifice 8. It may be constituted of any suitable plastic resin. The upper end is formed with an enlarged flange 9 by which the syringe may be manually held or secured to a suitable pressure-generating device. The top surface 10 of the flange is generally flat. The nozzle end 7 can be closed off with a removal cap 11 which may be held on the nozzle by a friction fit, or it may be closed off by any other device, such as a pin, or peel-away closure, or the like.

A centerboard 13 made for example of plastic is disposed in the center of the barrel 6. The centerboard 13 comprises a flat member whose edges engage the inside surfaces of the barrel walls. The thickness of the centerboard 13 is such that its bottom edge closes off the entrance to the nozzle 7. The centerboard 13 divides the barrel into two isolated, side-by-side vertical compartments 14, 15 of equal volume with each having a semi-cylindrical shape.

A member 16 closes off the top open end of the barrel. In a preferred form, the member is a foil which comprises a thin metal or plastic cup-shaped member having a flange portion 17 which seats on the syringe flange 9 and a depending portion 18 which seats within the barrel 6. The foil contains a transverse slot 19 which extends across the full width up to the barrel walls. The slot 19 has a width and length sufficient to accommodate the centerboard with a close fit and yet will allow the latter to slide relative to the foil. At the bottom of the centerboard, at opposite sides, are provided small projections or protuberances 20 whose spacing is larger than the slot width. The centerboard 13, at its upper portion extending above the barrel, is provided with a hole 21 to receive a finger or thumb of the user.

In operation, the centerboard 13 is seated within the syringe barrel 6 and then each of the compartments 14, 15 is loaded with the proper proportions of two constituents which make up the mixture to be formed, shown respectively at 22, 23. Then, the foil member 16 is placed in position. The entire top can then be secured by plastic tape or packaged in a tight plastic stretch material to hold the assembly in the position illustrated in FIG. 1 with the centerboard separating the two constituents and preventing their reaction. In that form, the loaded syringe can be distributed to the user who will retain same until ready for use.

In use, the skin package is removed, and then while holding the foil 16 in place with one hand, the centerboard 13 is removed with the other hand. During removal of the centerboard through the slot 19, any constituents adherent to the centerboard sides are wiped off the board by the foil and fall back into the syringe barrel to maintain the desired proportions. When the projections 20 reach the foil, the user releases the latter and the foil closure 16 is completely removed with complete removal of the centerboard, as illustrated in FIG. 3. Next, a suitable mixing tool such as a spatula 25 can be inserted through the open barrel end and the constituents thoroughly mixed to form the desired mixture 26, as shown in FIG. 4. Then the mixing tool 25 is removed, a suitable plunger 27 with attached rod 28 inserted through the open end, the nozzle cap 11 removed, and by driving the plunger downward, as shown in FIG. 5, the thoroughly mixed constituents 26 can be extruded and dispensed as desired. After use, the syringe may be disposed of.

FIG. 6 shows a construction employing a modified centerboard 30 free of the protuberances at its bottom. The parts of this modification that remain the same as that of FIG. 1 bear the same reference numerals. In this case, when the centerboard 30 is removed, as before, the foil cup 16 acts to wipe the sides clean but now the centerboard can be removed without removing the foil cup 16. Then, a mixing tool in the form of a flat spatula 31 with flat or serrated edges 32 as shown in FIG. 7 is inserted through the slot 16 (the view in FIG. 7 is at right angles to that of FIG. 6) and the two constituents can be thoroughly mixed by rotating the mixer with the foil 16 in place to prevent loss of any contents. When the mixer 31 is rotated, the foil cup 16 will rotate with the mixer. After complete mixing, the tool 31 is removed, the foil cup 16 is removed, and then the plunger 27 as shown in FIG. 5 is inserted to extrude the mixed mass.

As is known, for more uniform mixture dispensing, a pressurized air system can be coupled to the syringe. This is achieved by inserting a shankless plunger in the barrel open end, and then attaching a suitable air-valve to the open end of the barrel using its flange to hold the air-valve in place. A supply of pressurized air is coupled to the air-valve. On pressing the air-valve actuator, air under controlled pressure pushes the plunger uniformly into the barrel expelling the mixture from the orifice.

As has been mentioned above, the invention is generally applicable to any two-component mixture which requires component separation up until the moment of use, and then intimate contact of the components in roughly equal proportions in the device enabling rapid and controlled dispensing where desired. Typically, the components will be of the liquid type that undergo a chemical reaction when brought into contact with one another. The device of the invention is best suited for heavy components because these are the most difficult to mix by the prior art constructions and also the heavier the components the smaller risk of leakage between the two compartments. In many of these mixtures, such as epoxies and dental impression material, such as silicone resins, a reaction occurs immediately upon contact causing setting in some cases in as short as 3 minutes. Thus, the constituents have to be thoroughly mixed quickly and applied quickly. An important advantage of the construction of the invention is that, upon removal of the centerboard, full and complete contact over a broad area exists between the constituents and thus, even if very viscous, they can rapidly and easily be mixed as required. Since the two compartments are of the same size, the device of the invention is best suited for mixing roughly equal proportions of constituents, but it is also possible to use same to make mixtures involving varying amounts of the different constituents.

While the closure 16 has been described as a cup, the invention is not limited thereto, and any form of slotted closure or stopper can be employed. For instance, the closure 16 can be a stopper similar to the plunger 27 of FIG. 5 with a slot in the center to accommodate the centerboard. With a stopper of resilient material, an advantage is that it seals off the open end of the syringe and will also seal against the centerboard, thereby eliminating the need of an additional seal on top. The stopper is removed with the centerboard for later insertion of the mixing tool.

Also, the bottom of the syringe 7 need not be funnelled down to a small orifice. For mixing very heavy materials, the bottom piece 7 can be made in the form of a detachable cap which is removed after mixing to make available at the bottom an opening having the full width of the syringe for extruding the heavy materials.

While the principles of the invention have now been made clear in several illustrative embodiments, there will be immediately obvious to those skilled in the art many modifications in structure, arrangement proportions, the elements, materials, and components, used in the practice of the invention, and otherwise, which are particularly adapted for specific environments and operating requirements, without departing from those principles. The appended claims are therefore intended to cover and embrace any such modifications, within the limits only of the true spirit and scope of the invention.

Claims

What is claimed is:

1. A disposable syringe and mixing assembly comprising a syringe barrel having a closed exiting orifice at one end and an opening at the opposite end, a removable centerboard disposed in the barrel and engaging the barrel walls and forming two side-by-side compartments each for receiving one of two components of a mixture to be formed, and a closure mounted at the opening at the opposite end of the syringe barrel, said closure having a slot, said centerboard extending through said slot.

2. A disposable syringe and mixing assembly as claimed in claim 1, and further including means for mixing the two constituents after removal of the centerboard, and means for expelling the mixture from the exiting orifice.

3. A disposable syringe and mixing assembly as claimed in claim 1 wherein the exiting orifice is small and the opposite end opening is larger, and the centerboard closes off the orifice.

4. A syringe and mixing assembly as claimed in claim 3 wherein the opposite end of the barrel has a flange, and the closure has a flange adapted to seat on the barrel flange.

5. A syringe and mixing assembly as set forth in claim 4 wherein the closure is of foil and further comprises a portion depending from the flange and adapted to seat within the barrel opening.

6. A syringe and mixing assembly as set forth in claim 2 wherein the closure slot closely fits the centerboard whereby the closure functions to wipe the centerboard during its removal.

7. A syringe and mixing assembly as set forth in claim 6 wherein a small protuberance is located at the bottom of the centerboard and functions to engage and lift off the closure during removal of the centerboard.

8. A syringe and mixing assembly as set forth in claim 2 and further comprising a paddle tool adapted for insertion into the barrel, and a plunger for engagement with the barrel interior.