Mixing Syringe

Abstract

A double barrel carpule type syringe having, at its discharge end, a common mixing and dispensing chamber provided with a rotary agitator driven from a motor on the syringe. One barrel of the carpule contains an elastomeric base material and the other an accelerator, therefor. The syringe has a double plunger by means of which the base material and the accelerator are simultaneously discharged into the chamber in prescribed proportions as the mixed material is discharged from the end of the chamber. The mixing chamber assembly and the carpule assembly are readily removable from the body of the syringe.

Description

SUMMARY OF THE INVENTION

This invention relates to a dental mixing syringe, and is more particularly concerned with a device for mixing elastic impression material immediately prior to the material being discharged into the mouth of a patient for creating an impression of a tooth.

In the past, numerous elastic or elastomeric impression materials have been produced, each of these being a two component system containing an accelerator and a base. According to prior art practices the two components are mixed together in open air, on a pad, and then transferred to the syringe used to place the material in its proper position surrounding the prepared teeth. This method has many problems, some of them are (1) messy (2) time wasted (3) odor when using many materials (4) need for spatula and mixing pad (5) excess force needed to eject the material from the syringe, when using the syringe in placing the material around the last prepared teeth in a multiple tooth impression due to the material beginning to set up in the syringe. It is, therefore, common practice among dentists to utilize a dental technician or assistant to prepare the material and assist him so that the dentist can concentrate on the preparation of the mouth for receiving the impression material and to apply the material rapidly so as to minimize the problems as much as possible.

Briefly described, the present invention which obviates the difficulties described above is a multi-cylinder syringe having a removable, double barrel carpule. One cylinder or barrel of the carpule contains the base while the other contains the accelerator. The syringe has a pair of plungers which simultaneously discharge the liquid, i.e. base and accelerator, contained in the respective cylinders into one end of a common chamber where an agitator, driven by a motor, thoroughly mixes the same and provides for the discharge from the other end of the mixed material. The device is held as a conventional syringe, and the rate of depression of the plunger regulates the discharge of material.

The term carpule, as used herein, means a fluid container comprising one or more cylindrical barrels and adapted for insertion in a syringe.

Accordingly, it is an object of the present invention to provide a mixing syringe which is inexpensive to manufacture, durable in structure and efficient in operation.

Another object of the present invention is to provide a mixing syringe which will uniformly mix two fluids and provide for the discharge of the mixed fluids at a manually controlled rate therefrom.

Another object of the present invention is to provide a dental mixing syringe which will accurately measure and adequately mix the ingredients of an impression material, and thereafter dispense prescribed increments of the resulting mix.

Another object of the present invention is to provide a dental mixing syringe which will waste very little material and will save time and effort in enabling a dentist to mix the accelerator and base of impression material in a person's mouth immediately prior to dispensing the same.

Another object of the present invention is to provide a dental mixing syringe which will mix and dispense the material in small portions so that the consistency of the material is always the same no matter how many teeth are involved in the impression.

Another object of the present invention is to provide a method of mixing impression material which will confine the odor of the mixed material and which will provide a convenient and non-messy way of producing a thoroughly mixed impression material.

Another object of the present invention is to provide a dental mixing syringe in which the carpule therefore may be readily and easily inserted and in which the nozzle assembly therefore may be readily and easily changed, as desired.

Another object of the present invention is to provide a method of mixing a dental impression material which will obviate the necessity of a mixing pad and a spatula.

Another object of the present invention is to provide a disposable nozzle assembly for a dental mixing syringe, the disposable nozzle assembly being inexpensive to manufacture, efficient in operation and readily attached and removed from the syringe body.

Another object of the present invention is to provide a disposable multi-barrel carpule which may be readily and easily inserted into a syringe body for use, and readily and easily removed therefrom after use.

Another object of the present invention is to provide a dental mixing syringe which will permit the partial mixing of two liquids within two juxtaposed barrels in prescribed amounts and will enable the mixed material to be discharged directly from a mixing zone into the mouth of the patient.

Other objects, features and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings wherein like characters referenced designate corresponding parts and wherein:

DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of a dental mixing syringe constructed in accordance with the present invention;

FIG. 2 is an enlarged fragmentary perspective view of the mixing nozzle assembly of the syringe disclosed in FIG. 1;

FIG. 3 is a vertical sectional view of the syringe shown in FIG. 1, the cover of the syringe body being open to disclose the double barrel carpule received therein;

FIG. 4 is a rear, partially broken away, vertical sectional view of the backside of the syringe illustrated in FIGS. 1 and 3;

FIG. 5 is an enlarged, vertical sectional, fragmentary view showing the discharge nozzle portion of the mixing tube of the syringe shown in FIG. 1;

FIG. 6 is a cross-sectional view taken substantially along lines 6--6 in FIG. 3;

FIG. 7 is a schematic electrical diagram showing the one circuit arrangement for the motor of the syringe shown in FIG. 1;

FIG. 8 is a view similar to FIG. 7, showing a second embodiment of the electrical arrangement for the motor; and

FIG. 9 is a view similar to FIGS. 7 and 8 but showing still a third embodiment of the electrical circuitry for the motor of the syringe, shown in FIG. 1.

DETAILED DESCRIPTION

Referring now in detail to the embodiments chosen for the purpose of illustrating the present invention, numeral 10 denotes generally the metal body of the syringe which body includes a pair of opposed carpule receiving or housing members, i.e. a cradle 11 and a cover 12, hinged along a common edge by a piano hinge 13.

The base housing member or cradle 11 includes a pair of parallel, concaved, juxtaposed, semi-cylindrical grooves or inner surfaces 14 and 15 which merge along a central ridge 16, so as to provide a receiving cradle for the double barrel carpule, denoted generally by numeral 20.

The double barrel carpule 20 includes a pair of hollow, clear plastic, tubular barrels or cylinders 21 and 22 which are joined axially throughout their length by a rectangular petition plate 23. The petition plate 23 is disposed along the plane, common to the axes of the cylinders 21 and 22. At one end of the plate 23 is provided an ejector lever 24, projecting sidewise or normal to the plane of 23.

Preferably, the double barrel carpule 20 is cast as an integral or unitary member, the cylinders 21 and 22 being provided respectively with a pair of axial, cylindrical or uniform diameter bores 25 and 26, throughout their lengths.

As is common in carpules, liquid within the bores 25 and 26 are confined by rubber or resilient sliding plugs 27 and 28 and fixed plugs 29 and 30. As will be understood by those skilled in the art, liquid is discharged from the interior of the bores 25 and 26 by puncturing the plugs 29 and 30, respectively, and by urging the sliding plugs 27 and 28 inwardly toward plugs 29 and 30.

The lever 24 is provided for the purpose of permitting the carpule 20 to be tilted out of the base member or cradle 11, when the syringe body 10 is open. This lever 24 tapers outwardly and is provided with a rounded knob 31 at its distal end. It is disposed approximately parallel to the piston end of the double barrel carpule 20.

The hinged cover member 12 is pivotally carried by the cradle or base member 11 and is adapted to pivot about the piano hinge 13 from an open position, as seen in FIGS. 1 and 3, to a closed position, as illustrated in FIG. 4.

The outer edge 32 of the cover member 12 which is opposite the edge containing hinge 13 is provided with one element; namely, a latch 33 of a detent, the latch 33 having an inwardly projecting lug 34 which is received in an opening 35 in the outer side edge 36 of the cradle member 11, when the cover 12 is closed against the cradle member 11.

The inner surface of the cover member 12 is complementary to the inner surface of the cradle member 11, including a pair of juxtaposed semi-cylindrical surfaces 37 and 38 which are joined along a central ridge portion 39.

It will be understood that when the cover member 12 is closed against the cradle member 11, the surfaces 38 and 14 define a cylinder having a longitudinal axis and adapted to confine the cylinder 21. In like manner, the opposed concaved surfaces 15 and 37 confine the cylinder 22. The opposed ridges 16 and 39 thus receive and clamp, therebetween, the plate 23. Hence, the double barrel carpule 20 is confined by the cradle member 11 and the cover member 12 against a lateral movement, when the lug 34 is received in the aperture 35.

For confining the double barrel carpule 20 against longitudinal movement, with respect to the body 10, the forward end portion of body 10 is provided with a nozzle member receiving cap, denoted generally by numeral 50. Furthermore, the rear end of body 10 is provided with a flat transversely extending handle or finger grip, denoted generally by numeral 60, the extremities of which protrude outwardly of member 11 and 12 to provide finger receiving wings 61 and 62. The wings 61, 62 extend in opposite directions outwardly in generally radial directions from the body 10, as seen best in FIG. 1, and are concaved facing downwardly, as best seen in FIGS. 3 and 4 so as to provide concaved lower surfaces 63 and 64 for receiving the fingers of a person which grasp the instrument.

Between the wings 61 and 62, the end plate 60 is flat, being provided with generally cylindrical, juxtaposed, merged abutment plates 65 and 66 which limit the upward or rearward movement of the carpule 20. Furthermore, these abutment plates 65 and 66 slidably receive, through their respective centers, a pair of parallel disposed spaced piston rods 67 and 68 of the plunger 70. The forward end of the piston rods 67 and 68 are provided with flat plate like pistons 71 and 72 which abut against the inner surfaces of the abutment plates 65, 66 to limit outward movement of the plunger 70 and abut the plugs 27, 28.

The outer ends of the piston rods 67 and 68 are connected by a common transversely extending handle 73. The handle 73 is disposed in approximately a parallel position with respect to the end plate 60. The distance from the handle 73 to the end plate 60 is the stroke of the plunger 70, being such that with the plunger extended, the instrument may be grasped in a person's hand with a pair of fingers of his hand looping under and receiving the surfaces 63 and 64 as the ball of the hand or the thumb receives the top or outer surface of the handle 73. In such a manner, the piston rods 67 and 68 may be urged axially inwardly from a position shown in FIGS. 1, 3 and 4 to a position in which the handle 73 is disposed adjacent the end plate 60, whereby the pistons 71 and 72 are urged their full distance through the cylinders 21 and 22, urging plugs 27, 28 downwardly or inwardly toward and against plugs 29, 30. The forward or downward movement of the carpule 20 is arrested by the cap 50.

The forward end of cap 50 is cylindrical, being provided with external threads 51 which receive the internal threads 52 (seen in FIG. 3) of a collar or sleeve 53 of the nozzle assembly 80.

In more detail, the clamping collar or the sleeve 53 includes a cylindrical portion 54 having the internal threads 52 and having its outer surface knurled, at numeral 55, so that it may be readily rotated on and off the cap 50. The forward end portion of the sleeve 53 is provided with a flat plate 56, the central portion of which is provided with a circular aperture 57 for receiving the nozzle assembly, denoted by numeral 80. The inner surface of plate 56, which defines the central opening therein, is tapered outwardly toward the discharge end of the syringe.

The nozzle assembly 80 includes a clear plastic mixing tube 81, having an inner frustoconical or flaring proximal cylindrical hollow tubular end 82 which is received in the tapered central hole of plate 56. The distal end 83 of the mixing tube 81 tapers axially outwardly and is curved to terminate in a small radially facing discharge opening 84, through which the mixed material is discharged.

The nozzle assembly 80 also includes an end bearing or spider 85, seen best in FIGS. 2 and 3, received within the cylindrical portion of the mixing tube 81. The spider 85 includes a central journal or hub from which radiate circumferentially equally spaced outwardly extending arms. The ends of the arms of spider 85 engage the inner surface of the mixing tube 81. The journal portion of the spider 85 receives the end of a central axially disposed shaft 86 of a rotatable agitator, denoted generally by numeral 87. The shaft 86 is provided, as best seen in FIG. 2, with a plurality of radially extending mixing fingers or rods 88. Rods 88 are axially and circumferentially spaced along the length of shaft 86 to provide effective means for mixing the base material and accelerator and for advancing the mixed material through tube 81.

The shaft 86 projects throughout substantially the entire length of the mixing tube 81, terminating at its lower end in the journal of spider 85. Its upper or inner end extends through the tapered proximal end 82, being journaled by a cone shaped or frustoconical journal block, denoted by numeral 90. The inner end or protruding end of the shaft 86 passes through and beyond block 90 and is splined at numeral 89, so that it may be received in the circumferential spaced lands and grooves in the center of a drive pinion 90, seen in FIGS. 1, 3 and 6.

Pinion 91 is disposed within a central counterbored recess of the cap 50. The teeth of pinion 91 mesh with a laterally off-set drive cog 92 which is also recessed in cap 50. The drive cog 92 is received on the end of a drive shaft 93 extending from an electrical motor 94 which is nestled between the convexed outer surfaces of the lobes of cradle member 11.

A motor housing 100, the inner edge portion of which conforms to outer surface of the cradle member 11, encases the motor 94, the housing 100 being sufficiently large that it also receives the "A" batteries 96 and 97, on opposite sides of motor 94, as illustrated in FIG. 4. The housing 100 thus confines the motor 94 in place for driving, by the cog wheels 92 and pinion 91, the shaft 87. Coil springs 98 and 99 in housing 100 urge the batteries 96 and 97 into their appropriate positions.

As seen in FIG. 3, the pinion 91 is carried for rotation by a stub shaft 95 which projects through a central opening in the cap 50, the stub shaft 95 having an enlarged retainer flange 101 on its end for preventing outward movement of pinion 91.

On opposite sides of the splined end 89 of shaft 87, the conical journal block 90 is provided with spaced, parallel, outwardly projecting eduction tubes 102 and 103, the ends of which are beveled at numerals 104 and 105, respectively, so as to provide pointed ends which are adapted to penetrate the end plugs 29 and 30, respectively, of the carpule 20 when the carpule 20 is inserted into the cradle member 11 or when the mixing nozzle 80 is installed in place on cap 50. The eduction tubes 102 and 103 are disposed parallel to each other and are equally spaced on opposite sides of the major axes of the syringe. These tubes 102 and 103 communicate with channels 106 and 107, on the surface of journal block 90, which in turn communicate with the interior mixing chamber of the mixing tube 81, adjacent the proximal end 82.

The cap 50 is provided with a pair of parallel apertures for holes 108 and 109, seen best in FIG. 1, through which the eduction tubes 102 and 103 pass. Since the eduction tubes 102 and 103 are longer than the thickness of cap 50, they project through the plugs 29 and 30 so as to terminate within the cylinders 21 and 22, respectively. Therefore, downward movement of the plunger 70, will urge the liquid from the respective chambers of cylinders 21 and 22, through the eduction tubes 102 and 103 and thence down the passageways 106 and 107, respectively, so that they are co-mingled as they enter the cylindrical part of the mixing tube 81. The rotation of motor 94 through its gear train, including cog wheel 92 and pinion 91, rotates the shaft 86 thereby causing the rods 88 to travel in rotary paths so as to mix the two ingredients fed into the mixing tube.

Further, depression of plunger 70 urges this mixed material out of the discharge opening 84 of the mixing tube.

By regulating the distance traveled by the plunger 70, the quantity of material mixed and discharged from the mixing tube 81 may be quite accurately regulated.

In FIGS. 7, 8 and 9 are three different ways of supplying current to the motor 94. In each instance, there is a lever 120, mounted for pivoting on a transverse pivot pin 121 carried by cradle member 11.

One end of lever 120 projects inwardly of cradle member 11 and terminates in the central portion thereof, so as to be urged upwardly or outwardly by coiled spring 122, seen in FIG. 3. The upward movement of the inner arm, however, is arrested by the handle 60. The outer end of lever 120 protrudes below the wing 62 of the handle 60 and is normally in spaced relationship thereto so that when the lever 120 is urged into juxtaposition or to a position contiguous with the wing 62, a circuit is made to energize or actuate a motor 64.

In the embodiment illustrated in FIG. 7, a normally open switch 123 is closed when the lever 120 is pivoted in a counterclockwise direction. This switch 123 is in series with the batteries 96, 97 and motor 94. In more detail, one wire 124 connected to one terminal of switch 123 is connected to the negative side of battery 196. The other wire 125, leading from the other terminal of switch 123 is connected to the motor 94. The motor, in turn, is connected to a positive terminal of battery 97 via wire 126 while the two batteries are arranged in series, through wire 127. Hence, the closing of switch 123 completes a circuit to the motor 94. Since the spring 122 urges the lever in a clockwise direction, the switch 123 is normally open until the lever is rotated, as aforesaid.

In FIG. 8, it will be seen that if desired the motor may be driven from a "power pack" illustrated generally by numeral 130. Current is supplied to the power pack at intervals by terminals 131 and 132. The switch 133 completes a circuit from the power pack 130 to the motor 194 to drive the gear train heretofore described.

If desired, the motor may be connected through an extension cord (not shown) which connects the motor 294 to line current from an external source. In such an arrangement, the terminals 141 and 142 supply current by normally opened switch 143 and fuse 144 to the motor 294. It will be understood that the lever, such as lever 120, closes switch 143 and that the springs, such as spring 122 in FIG. 3, opens the switch 143 when the lever 120 is not depressed. It will also be understood that the motor 294 functions in identical fashion to the motor 94.

It is now seen that when carpule 20 is installed in the cradle 11, the axes of pistons 6, 7 and 8 are respectively aligned longitudinally of the syringe with the axes of cylinders 21 and 22. Also the axes of passageways 108 and 109 are aligned respectively with the axes of cylinders 21 and 22. Therefore, the axes of eduction tubes 102 and 103 are aligned respectively with the axes of cylinders 21 and 22.

Furthermore, one component axis passing through piston 67, cylinder 21, passageway 108 and eduction tube 102 is on one side parallel to the major axis of the syringe, i.e. the axis of shaft 86, while the other component axis passing through piston 68, cylinder 22, passageway 109 and eduction tube 103 is equidistance from and parallel to the major axes on the other side, thereof.

It will also be observed that when plunger 70 is in its most retracted position the pistons 71 and 72 are recessed into cavities in the plates 65 and 66 so that exposed surfaces of pistons 71 and 72 are in a common plane with the inner surface of plates 65 and 66. Also, the distance from plates 65, 66 to cap 50 mounted on opposite ends of cradle 11, is slightly greater than the length of carpule 20 so that it may be snugly received by the cradle 11.

OPERATION

From the foregoing description, the operation of the present device is quite apparent. First, a carpule 20, containing the base in one cylinder 21 and the accelerator in another cylinder 22, is installed in the cradle member 11. Then the cover 12 is closed thereover, the detent, including latch 34, latching the cover in place in apposition to the cradle member 11. This confines the double barrel carpule 20 in place, aligning the slidable plugs 27 and 28 with the pistons 71 and 72. It will be understood, of course, that prior to the installation of the carpule 20 in place, the plunger 70 must be retracted to its outermost position, as shown in FIG. 1. It is also to be understood that the nozzle assembly 80 is not installed, at this stage.

After the carpule 20 has been installed and clamped in place by closing of the cover 12, the nozzle assembly 80 is installed by inserting the eduction tubes 102 and 103 through the passageways 108 and 109 and thence through the central portions of the stationary plugs 29 and 30 so that the pointed tips or points 104 and 105 pass through the plugs 29 and 30 and terminate within the chambers of the cylinders 21 and 22.

Thereafter, the collar 53 is threaded onto the cap 50. Of course, the inserting of the eduction tubes 102 and 103 through the passageways 108 and 109 automatically align the spline 89 so that it will be received in the lines and grooves of the pinion 91. When the syringe is ready to be used, the operator grasps the syringe with his fingers engaging the wings 61 and 62, one finger looping over the lever 120. The base of the thumb of the operator's hand can rest against the handle 73 so upon contracting of the fingers of the hand, the plunger 70 will be urged inwardly, while simultaneously therewith the lever 120 is depressed against the wing 62 so as to actuate the motor 91, 191 or 291, as the case may be. This commences rotation of shaft 87 so that the mixing rods 88 mix the material as such material is discharged simultaneously through the eduction tubes 102 and 103 and thence via passageways 106 and 107 into the chamber of the mixing tube 81. Thence, as explained above, the thoroughly mixed accelerator and base material is discharged from opening 84.

The syringe, thus described, is of such a size that the nozzle assembly and the body of the syringe may be inserted into the open mouth of a patient so that the mixed material may be directed against the appropriate tooth for making an impression of such tooth.

Since the material is not exposed to the atmosphere in the mixing tube, no appreciable odor is apparent from the mixing thereof.

When the operation of the device is completed, the plunger 70 may be retracted quite readily and the nozzle assembly 80 removed.

In some instances, it is only necessary to remove from the nozzle assembly, the mixing tube, so that it may be flushed out, and the agitator shaft 87 washed. Since the passageways 106 and 107 open outwardly, once the mixing tube has been removed, these passageways may be flushed out as well as the eduction tubes 102 and 103. The nozzle assembly, illustrated in FIG. 2, is so inexpensive, however, that it may be disposed of in toto so that a sterile and clean nozzle assembly can be used for each successive patient. Also, the carpules 20 are readily removed by the opening of cover 12 and replaced for successive patients or successive operations of the plunger.

Claims

What is claimed is:

1. A mixing syringe comprising a syringe body including a pair of body members, a hinge disposed along and joining the sides of said members, said members forming a cradle and a cover, said cover being movable in an arcuate path to and away from said cradle, the inside surfaces of said members each including a pair of concave surfaces joined along a common convex central ridge extending longitudinally of said member, a carpule received between said members, said carpule including a pair of hollow, cylindrical parallel disposed barrels open at both ends, a partition joining said barrels for maintaining the same in their parallel relationship, a cap at one end of said body mounted on one body member, a transversely extending plate mounted on said one body member at the opposite end thereof from said cap, the distance between said handle and said cap being approximately the length of said carpule, said plate extending outwardly of said one member on both sides thereof, a plunger including a pair of spaced parallel slidable pistons carried by said plate, a handle joining the outer ends of said pistons so as to maintain the same in parallel relationship, said carpules including a pair of plugs in the ends of both of said cylinders and a fluid material within said carpule cylinders, a pair of said plugs being disposed adjacent said pistons when said carpule is installed in said one member and being movable towards the other plugs of said cylinders when said plunger is pushed inwardly of said one member, a removable nozzle assembly mounted on said cap, a collar on said cap for maintaining said nozzle assembly in position on said cap, said nozzle assembly including a mixing tube, an agitator within said mixing tube, said agitator including a shaft disposed along the axis of said tube and agitator members extending from said shaft, a spider within the distal end of said mixing tube receiving one end of said shaft, a journal block within the other end of said mixing tube, said shaft extending through said journal block and therebeyond, said shaft terminating in the splined end, said journal block and the proximal end of said mixing tube being retained in place by said collar, a pair of eduction tubes on opposite sides of said shaft and extending from said journal block, said journal block being provided with a pair of passageways communicating with said eduction tubes, respectively, and also communicating with the proximal end of said mixing tube, said eduction tubes extending parallel to each other and terminating in pointed ends, said cap being provided with passageways, said passageways receiving said eduction tubes when said nozzle assembly is mounted on said cap, said eduction tubes being of sufficient length that they penetrate through the plugs in the ends of said cylinders when said carpule is installed in said one member and when said nozzle assembly is installed on said cap, a gear train within said cap, said gear train receiving the splined end of said shaft when said nozzle assembly is mounted on said cap, said mixing tube being provided at its distal end with an opening through which a mixture of the fluid materials contained in said carpule which are fed through said eduction tubes and said passageways in this mixing tube are discharged therefrom, a motor within said body for driving said gear train, and detent means for maintaining said body members in a closed position around said carpule.