Dental syringe apparatus and method

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DENTAL SYRINGE APPARATUS AND
METHOD

FIELD OF THE INVENTION 5

This invention relates to the field of dentistry, and more specifically to orthodontics syringe apparatus of the type having a handle at one end and having an intra-oral nozzle at the other end.

BACKGROUND OF THE INVENTION

Hand-held syringes that control the flow of a liquid and/or air into a body cavity such as the oral cavity are known. Typically, such a syringe is an L-shaped device having a 15 handle, a nozzle, and one or more finger-actuated valves that are spring-biased closed, and whose operation controls the outward flow of liquid and/or air from the nozzle, with the handle being connected to one or more flexible and underpressure fluid/air supply hoses. Often these valves are the 20 well known Schrader valves of the type used in pneumatic tire stems. In this way, fluid, air, or a mixture of fluid and air can be selectively discharged from the nozzle. The following United States patents are examples of known prior devices. These patents are incorporated herein by reference. 25

U.S. Pat. No. 5,045,055 provides a medical/dental syringe that includes an elongated handle having a nozzle connected to one thereof, and having a two-hose assembly connected to the other end thereof. The handle includes a valve body head, two flow-control valves, and two finger actuators for 30 the flow-control valves, to thus selectively control the flow of water, air, or both water and air from the nozzle. The two flow-control valves, and their O-rings, are removable to facilitate periodic replacement. The use of VITON-brand O-rings is suggested in order to resist the effect of repeatedly 35 subjecting the O-rings to high temperature. Automatic valves within the two-hose assembly operate to seal the water hose and the air hose when the two-hose assembly is disconnected from the handle.

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U.S. Pat. No. 5,125,835 provides a retainer assembly for detachably mounting the multiple-conduit tip of a syringe onto a syringe head by way of a spring-biased locking collar. The tip includes an annular groove that receives a plurality of ball elements when the tip is inserted into the syringe ^ head. A movable and spring-biased collar that is carried by the syringe head retains the ball elements within the tip's groove, thus removably mounting the tip on the syringe head.

U.S. Pat. No. 5,199,871 provides a control valve for a 50 dental syringe. The control valve, having a finger-actuator, is mechanically locked in a passageway that is provided within a syringe-head by the operation of an O-ring that expands into a groove that is provided in the wall of the passageway.

U.S. Pat. No. 5,234,338 provides an autoclavable head 55 and handle for a dental syringe wherein the entire external housing, including the handle, can be removed from utility supply lines, so that the external surfaces of the housing can be autoclaved. This function is facilitated by providing a substantially internal quick-disconnect mechanism or car- go tridge whereby the flow of air and water to the syringe is discontinued, such that the syringe's handle, head and tip can be steam-sterilized.

U.S. Pat. No. 5,848,893 provides that a syringe's shutoff valves are mechanically retained in place within a syringe 65 head by way of a retaining pin that seats within a groove that is contained within each of the shutoff valves, this retaining

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pin entering the groove when that valve's inlet hose barb is screw-mounted onto the syringe head. In addition, the syringe nozzle is retained in an adapter that screw-mounts to the syringe head by way of a resilient snap-ring that encircles the nozzle and sits within a groove that is formed in the nozzle.

U.S. Pat. No. 6,293,792 is similar to above-mentioned '835 patent wherein the ball-activated quick-tip-connect mechanism is constructed so as to also seat the balls of the quick-connect mechanism in radially-placed indentations that are carried by the tip. In this way the balls additionally provide structural interference against rotation of the tip.

SUMMARY OF THE INVENTION

The present invention provides a new and useful dental syringe that is constructed and arranged such that the internal portions of the syringe that contain O-rings, or at least the portion of the syringe that contains valve-associated O-rings, can be removed from the syringe prior to the syringe being sterilized, as by autoclaving. Thus, all O-rings that function within the syringe, or at least the O-rings that function within the syringe's valves, are constructed of a material such as neoprene that would likely be damaged by autoclaving.

In order to provide an aesthetically pleasing and nicely weight-balanced syringe, the syringe of this invention includes (1) an internal and top-located insert, which could be made of metal, plastic, or any other suitable material, to contain flow-channels and the like that are required to accommodate air and/or water flow between the syringe's two valves and the syringe's nozzle, (2) a generally hollow and light-weight metal handle-body at whose upper end a nozzle and the insert are located, and (3) an internallylocated and elongated light-weight, metal, and manuallyremovable valve body that extends internally the length of the handle body, so as to locate the syringe's two valves at the upper end of the handle body and generally adjacent to and beneath the insert, and so as to locate two hose barbs at the bottom of the handle body.

This construction and arrangement wherein the syringe's two normally-closed valves are placed at the top of a removable valve body whose bottom area contains two hose barbs to which water and air supply hoses are connected provides that when this valve body is manually removed or disconnected from the syringe, the syringe's two normallyclosed valves are removed with the valve body, and the two hoses are disconnected from the syringe, thus providing a removed valve body in which the two supply hoses are scaled by operation of the two normally-closed valves.

When assembling the syringe of the present invention, the syringe's insert is first inserted into an upper portion of the handle body. An insert assembly pin is then inserted into an opening that is provided in an upper portion of the handle body. This insert assembly pin penetrates an opening in the insert, and thereby secures the insert within the handle body. Two side-by-side located, virtual-center-movable, and semicircular valve actuating rods are carried by the insert, and this first assembly step places the top end of these two virtual-center valve actuating rods in positional cooperation with two O-ring-retained valve actuating buttons that are inserted into two side-by-side holes that are located on an upper inclined surface of the handle body.

As a second assembly step, the valve body is inserted into an opening that is located at the bottom of the handle assembly. This second assembly step places a normallyclosed air valve and a normally-closed water valve that are located at the top of the handle member under the insert, and in positional cooperation with the bottom end of the two valve actuating rods. The two curved valve actuating rods enable the linear direction of movement of the two buttons to be inclined to the linear direction of movement of the two valves.

As a third assembly step, a lock pin is inserted into an opening that is provided in the upper portion of the handle assembly. This lock pin is adapted to enter an O-ringcontaining groove that is provided in a spigot or post that is 1° carried at the top of the valve body. As will be apparent from the following description, the lock pin and a release ring together lock the valve body in the handle body.

The syringe's nozzle is connected to a manually rotatable release ring that encircles the outer diameter (OD) of the 15 nozzle. The release ring is secured to the nozzle by way of a coiled torsion spring, one end of which is retained by the release ring. The coil of this torsion spring grips the outer diameter (OD) of the nozzle. That is, the inner diameter (ID) of the torsion spring is somewhat smaller than the OD of the 20 nozzle. The release ring is secured to the body of the syringe by an assembly pin.

When assembling the release ring and the nozzle, one end of the torsion spring is retained by the release ring, and the ^ torsion spring is then rotated against its wound direction, to thereby produce a spring ID that is larger than the nozzle OD. With the spring held in this larger ID state, the nozzle is now inserted into the center of the release ring, and the release ring is placed at a desired location along the length 3Q of the nozzle. The torsion spring is now released, whereupon the ID of the torsion spring decreases, thereby causing the release ring to be rotatably mounted at this desired position on the OD of the nozzle.

As a fourth assembly step, the release ring is secured to 35 the body of the syringe with the assembly pin. The release ring presses against the lock pin and locks the valve body in the handle.

As the fifth and final assembly step, an end of the nozzle is inserted into the release ring by rotating the release ring 40 thereby unwinding the torsion spring so as to facilitate inserting the nozzle within the release ring and torsion spring. The release ring and torsion spring can then be released thereby securing the nozzle to the release ring. Later, when it is desired to disconnect the valve body from 45 the syringe, the above-mentioned release ring is rotated about 30 degrees around the nozzle. This rotation of the release ring coils the torsion spring, such that upon a subsequent release of the valve body, the release ring returns to its home position. This rotation of the release ring also 50 brings a recessed portion of the release ring into positional coincidence with the above-mentioned lock pin. The abovementioned O-ring that was compressed by the lock pin now operates to push the lock pin out of the above-mentioned groove in the spigot that is located at the top of the valve 55 body, the valve body is no longer locked by the lock pin, and the valve body can now be pulled downward and out of the handle body. Note that since the top of the valve body carries normally closed valves, the supply hoses that are connected to the bottom of the valve body remain sealed. go

As above described, syringes in accordance with this invention include two top-located and finger-operated buttons that, when pressed, selectively provide for the supply of pressurized air and/or water to the syringe's nozzle. In accordance with the invention, a new and unusual virtual- 65 center actuator rod extends between the bottom of these two buttons and the top of an associated valve, so as to translate

a linear force that is applied to a button into a linear valve-opening force that is applied to an associated valve. These two virtual-center actuator rods are arranged such that the direction of linear movement of each button extends at an angle to the direction of linear movement of the associated valve.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded side view showing a syringe in accordance with the invention;

FIG. 2 is a vertical section view of the FIG. 1 syringe wherein the section view is taken in a centrally located plane that produces center-sectioning of the syringe's nozzle;

FIG. 3 is an enlarged view of the upper portion of FIG. 2;

FIG. 4 is a vertical section view of the FIG. 1 syringe, this section view being taken in a plane that lies forward of the plane of FIG. 2, FIG. 4 showing the construction and arrangement of one of the two valves that respectively control the flow of air and/or water to the nozzle; and

FIG. 5 is an enlarged view of the upper portion of FIG. 4.

DETAILED DESCRIPTION OF THE
INVENTION

With reference to FIG. 1, reference number 10 designates a generally L-shaped dental syringe in accordance with the invention.

Syringe 10 includes a hollow handle body 11 that is preferable formed of aluminum, an elongated valve body 12 preferably formed of brass, plastic, or steel that is upwardinsertable into the open bottom of handle body 11, an internally-located insert 13 preferably formed of brass that is located at the top of handle body 11, and a nozzle 14 preferably formed of a metal such as stainless steel that extends generally 105-degrees outward from the top of handle 11. It should be noted that alternative embodiments of straight syringes with nozzles that extend approximately 180 degrees from the top of the handle 11 also fall under the teachings of this application.

After insert 13 has been manually inserted into an opening that is provided at the top portion of handle body 11, insert 13 is secured in this inserted position by the operation of a manually removable insert assembly pin 28. The insert 13 is preferably composed of either metal or plastic.

The bottom end of valve body 12 includes two side-byside located hose barbs 15, one of which is adapted to receive a hose and a shut-off valve (not shown) that is connected to a source of pressurized air, and the other of which is adapted to receive a hose and a shut-off valve (not shown) that is connected to a source of pressurized water.

Valve body 12 also includes two internal and upwardextending flow channels 19, one channel 19 of which is shown in FIGS. 4 and 5. The bottom end of each of these two internal flow channels 19 connects to an individual one of the two hose barbs 15, and the top end of each of these two internal flow channels 19 terminates at, and is closed by, an individual one of the two normally-closed valves 16 (best seen in FIGS. 4 and 5), one valve 16 of which is shown in an exploded position in FIG. 1. Each of the two valves 16 is spring-biased to a closed position by the operation of a coil spring 17 that encircles a metal valve stem 18, and each of the two valves 16 includes a valve stem O-ring 20, a valve seat 21 (best seen in FIG. 5), and a valve O-ring 23 (best seen in FIG. 5).

While not a limitation on the spirit and scope of this invention, the unique construction and arrangement of 5

syringe 10 advantageously enables the use of neoprene O-rings throughout syringe 10, or at least throughout the valves that are contained within syringe 10.

As a feature of the invention, a C-clip 24 as shown in FIG. 5 is installed in each of the two valves 16 such that valve 5 stem 18 and its various attachments, including valve seat 21 and valve seat O-ring 22, can be forcibly extracted from valve body 12 for maintenance.

With reference to FIG. 5, each of the two valve assemblies 16 is inserted downward into an oversize or relatively large 10 diameter hole 51 that is formed in the top of valve body 12, thus allowing valve seat O-ring 22 to pass the cross drilled holes 71 72 (shown in FIG. 3) without being damaged. Moreover, a tapered-diameter portion 52 at the bottom of hole 51 is provided to compress valve seat O-ring 22 within 15 valve body 12 in a gradual manner, as valve seat O-ring 22 reaches its final position whereat O-ring 22 settles into an annular groove 53 that is formed in the bottom portion of hole 51.

The bottom end of valve body 12 includes an alignment 20 pin 27 that extends outward therefrom. The positioning of alignment pin 27 ensures the correct physical position of valve body 12 within handle body 11. The stop pin 74 extends up from the valve body 12 between the two spigots 31 into a matching cavity in the valve insert 13 best shown 25 in FIG. 3.

The top end of valve body 12 (the spigots 31) and the mating interior surface of the insert 13 are preferably machined to provide an o-ring 32 seal so that air and water ^ does not leak downward through valve 16 (shown in FIG. 1) when one or more of these valves are opened as shown in FIG. 3. The fluid flows up through the cross drilled holes 71 72 shown in FIG. 3. The spigots 31 carry the fluids up into the insert 13 where o-rings 37 keep the water and air 3J separate while they transfer from the insert onto the separate concentric passages in the nozzle. With valve body 12 correctly inserted within handle body 11, the two side-by side located valves 16 that are located on the upper end of valve body 12 are correctly aligned with the physical position of two side-by-side located push buttons 25 that are carried by the top inclined surface 26 of handle body 11, this button/valve aligned position being best seen in FIGS. 4 and 5.

The top end of valve body 12 carries two metal spigots or 4J posts 31 that individually carry a number of O-rings 32, as is best seen in FIGS. 2 and 3.

In addition, and as is best seen in FIGS. 1, 2 and 3, a lock pin 46 operates to lock valve body 12 in its inserted position. Lock pin 46 slideably extends through a hole that is provided 50 in handle body 11, and the end of lock pin 46 is adapted to extend into an O-ring-containing groove 47 that is formed in a spigot 31.

When lock pin 46 is pushed to the right, as seen in FIG. 3, the end of lock pin 46 operates to compress the O-ring 32, 55 as lock pin 46 is held in this pushed-position within groove 47 by an edge 48 of release ring 42.

With reference to FIG. 3, when release ring 42 is manually rotated (as will be described below), a recessed cam surface (not shown) that is machined into the edge 48 of release ring 60 42 is brought into alignment with lock pin 46. The O-ring 32 that is within groove 47 now expands and pushes lock pin 46 to the left, out of groove 47, as the left end of lock pin 46 is pushed into this recessed cam surface.

With lock pin 46 in this left-ward position, where the right 65 end of lock pin 46 is no longer within groove 47, valve body 12 can be forcibly pulled out of handle body 11.

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The insert 13 is machined to facilitate transferring the air and water from the spigots 31 to the separate concentric passages 33, 73 in the nozzle.

With reference to FIGS. 1-3, the right end of nozzle 14 is releaseably mounted in an elongated linear cavity 36 that is formed in insert 13, this releasable mounting being facilitated by the wound torsion spring 38, as is best seen in FIG. 3.

The torsion spring 38 has its left end 39 rotationally constrained by release ring 42, and has its right end 41 secured in a similar fashion to the insert 13, such that forcible rotation of the release ring 42 uncoils the wound spring 38 and allows the nozzle 14 to be inserted. When the force rotating the release ring 42 is removed the torsion spring 38 acts to return to its coiled position forcing the release ring 42 back to its home position. As the torsion spring 38 recoils, its ID is reduced claming the nozzle 14 and holding it in place axially and to a lesser extent rotationally.

The relaxed ID of torsion spring 38 is somewhat smaller than the OD surface 40 of nozzle 14. When release ring 42 is in its not-rotated or home position, as seen in FIG. 3, torsion spring 38 relatively tightly grips the OD surface 40 of nozzle 14.

In an operation to manually remove valve body 12 from handle body 11, manual rotation of release ring 42 for about 30 degrees allows the lock pin 46 for the valve body 12 to retract into the chamber on the outer edge of the release ring 42 thereby releasing the valve body 12. In addition, the rotation of the release ring 42 30 degrees also causes the nozzle 14 to release. The ability to release both the nozzle 14 and the valve body 12 with a rotation of the release ring 42 is a design feature that simplifies operation of the syringe and manufacturing. With release ring 42 held in this 30-degree-rotated position, lock pin 46 moves to the left in FIG. 3, the right end of lock pin 46 is thus withdrawn from groove 47, and valve body 12 can be manually pulled out of the bottom of handle body 11.

That is, release ring 42 functions in its 30-degree-rotated position to cause lock pin 46 to be withdrawn from the groove 47 that is formed in a spigot 31 that is carried at the top of valve body 12, to thus enable valve body 12 to be manually withdrawn from handle body 11.

As perhaps best seen in FIG. 3, release ring 42 sits in an opening 56 that is formed at the side and top of handle body 11. The ID of release ring 42 freely rotates on the OD 57 of insert 13, and the inside face of release ring 42 freely rotates on the front face 58 of insert 13.

Release ring 42 is secured to handle body 11 by a release ring assembly pin 59 which is held by handle body 11 and which mates with a U-shaped groove 60 that is formed in a portion of the OD surface of release ring 42.

One end of U-shaped groove 60, which can be called the home position end, cooperates with release ring assembly pin 59 to act as a home-stop for release ring 42, as torsion spring 38 operates to hold this end of U-shaped groove 60 against release ring assembly pin 59.

When release ring 42 is rotated about 30 degrees, as above described, the opposite end of U-shaped groove 60 engages release ring assembly pin 59 and acts as a rotation-stop that prevents damage to torsion spring 38. It should be noted that in reality the valve body 12 is effectively released when the release ring 42 is rotated only 7 degrees and the remainder of the rotation is to allow the ring to unwrap enough to release the nozzle 14. Likewise, the syringe can be manufactured so as to allow the valve body 12 and or the nozzle 14 to effectively release at almost any angle of rotation of the release ring 42.