This application is a PCT Application taking priority and benefit of all common subject matter of US Provisional Patent Application 62118310 filed 19 February 2015.

Field of the Invention

The present invention relates to a new type of dental syringe system. Description of the Related Art

In the dental syringe art, the conventional syringe is adapted to allow the dentist to retract the syringe plunger after the initial stick, in order to ascertain that he has not hit a blood vessel, by using his thumb in the thumb ring of the syringe, pulling back on the plunger and observing the anesthetic vial to determine if blood has been pulled into the syringe. If it has, this indicates that he must find a new spot for the injection point in order to avoid injecting anesthetic into the bloodstream via a blood vessel. There are two reasons for this:

1. The anesthetic usually contains epinephrine, which can affect heart rate adversely.

2. If the anesthetic is taken away from the site by the blood vessel, it will fail to anaesthetize the site.

Thus, in contrast to the usual medical syringe used by doctors, in which the entire syringe is generally disposable, the dental syringe has a reusable metal framework. Medication is usually in a disposable cartridge. So this type of syringe is aiso known as a cartridge syringe. Background of the invention

The closest reference we are aware of in the art is the Present inventor's earlier Patent US 6764471 B2, Granted: Jul. 20, 2004, on Application number: US 10/008,373 Filing date Nov 13, 2001 , Priority date Nov 13, 2000 Inventor Alexander E. Lee

The present invention improves on the disclosure of said present inventor's prior patent. US Patent 6764471 B2 is hereby incorporated by reference.

Hospira™ (part of Abbott Labs™) has Carpuject™ syringes. See: http://en.wikipedia.org/wiki/Carpuject https://www.youtube.com/watch?v=r4a9E4oV6jY

Brief Description

The present invention provides a sheath, which snaps or screws on to threads on the needle-end, or tip, of the syringe to stabilize the needle during injection. This sheath will be made out of either plastic or metal and clipped onto the syringe.

This sheath will allow the insertion of a needle assembly, in the sheath's resting position.

We will define axial directions used in this application as: Tip-ward = towards the needle tip; and Ring-ward = toward the thumb ring or actuator ring = the opposite direction to tip-ward.

After insertion of the needle, this sheath will be rotated to push the needle assembly tip-ward, thereby seating a conical segment of the needle assembly, against a cooperatively shaped conical part of the interior of the syringe body's tip-ward end.

The sheath will thus stabilize the needle, and thereby facilitate changing anesthetic cartridges during multiple injections.

Further rotation of the sheath will cause the flexible sheath to jump the threads on the syringe and thereby relieve the seating pressure and allow the needle to fail from the syringe into a sharps container.

Aiternativeiy, reversing rotation of the sheath will also relieve the seating pressure and allow the needle to fall from the syringe into a sharps container.

Brief Description of the Drawings

Fig. 1 is a front elevation, of a dental syringe system of the present invention. Fig. 2 is a front elevation of part of a syringe of the present invention. Fig. 3 is a side elevation thereof. Fig. 4 is a front elevation of the sheath.

Fig. 5 is a front elevation of the tip-ward end of the syringe, without the sheath. Fig. 6 is a front lower perspective view of the syringe, sheath in position to receive a needle assembly, and a needle assembly.

Fig. 7 is a slightly oblique top perspective view of the sheath 20, looking in a thumb- ward direction.

Fig. 8 is a bottom plan view of the sheath, looking in a tip-ward direction. Fig. 9 is a front oblique view of the sheath.

Fig. 10 shows clearance 155 between inside wall 157 of sheath 20, and outside of conical wall 16 of syringe 5.

Fig. 11 is a side elevation of the sheath on the syringe. Fig. 12 is a side elevation of the syringe.

Fig. 13 is a front oblique side elevation of the sheath on the syringe.

Figure 14 is a front elevation of the syringe body.

Figure 15 is a top plan view thereof.

Figure 16 is a top plan view of the sheath.

Figure 17 is a front elevation thereof.

Figure 18 is a plan view of the body.

Figure 19 is a front elevation of said syringe body with the shaft mounted on the body. Figure 20 is a perspective view of the needle assembly. Figure 21 is a perspective view of the medicine cartridge. Figure 22 is a perspective view of the syringe, with the sheath holding the needle assembly firmly in the syringe.

Detailed Description of the Drawings

Figure 1 is a front elevation, of the present invention, which provides a dental syringe system. A dental syringe is also known as a cartridge syringe. There are some applications for this syringe and needle system, in the general medical field. If the medications are supplied in the cartridge form rather than a vial or ampule, then this cartridge syringe system can deliver the medications more: easily, simply, and safely.

The prior art requires a user to: aspirate the medications from the vials and ampules into the medical grade disposable (plastic) syringes, which typically use a large bore needles (20 or 22 gauge); and then inject the medications into a person,

The present invention can deliver the medications using the smaller bore needles, if the medications are placed into the cartridge form.

The system, when assembled, forms an assembly which is generally designated 3.

A syringe 5 comprises a thumb ring 7, and a finger grip 8, on a syringe body 9.

I will hereinafter describe and clam the thumb ring 7 as an actuator ring 7, to avoid claiming a human body part, the thumb.

Shaft 10 slidably mounts actuator ring 7 to syringe body 9. At the tip-ward end of shaft 10 is a harpoon 11. A medicine cartridge 12 is mountabie in syringe body 9 of syringe 5. Medicine cartridge 12 has a slidable seal 13, into which harpoon 11 can be inserted and anchored to form a plunger (13, 11 , 10, & 7) with shaft 10, which can then be slid: needle-ward; or ring- ward; by manipulating the actuator ring 7 in those directions. The ring-ward direction will be referred to in the claims as a ring-ward direction. The actuator ring 7 is configured to be controlled by a thumb, controlling the actuator ring 7 to expand or contract the volume of the cartridge.

Finger grip 8 comprises a recess 17, and a pair of flanges axial to the recess 17: tip-ward finger flange 18, and ring-ward finger flange 19.

But before harpoon 11 is inserted into the cartridge, needle assembly 14 is placed with a conical portion 15 seated inside the matching conical end 16 of syringe body 9. A removable sheath 20 is configured to retain the needle assembly in the syringe body 9.

The syringe body 9 has an external spiral mount 40 on the cylindrical portion of syringe body 9. The external spiral mount 40 includes a threaded matching groove or thread on the outside of the cylindrical portion of syringe body 9.

The sheath 20 has an internal spiral mount 50, which comprises an internal thread 50, having thread segments: 51 , 52, 53, 54, 55, 56, & 57.

The sheath 20 and its internal thread 50 may be rotated in a loosening direction, which would be counter-clockwise when viewed from the tip-ward end. This clockwise rotation causes the tip-ward end 21 of sheath 20 to push against flange 22 on a cylindrical portion 27 of needle assembly 14, and thereby seat conical portion 15 of needle assembly 14 firmly against matching internal, conical end 16 of syringe body 9.

Sheath 20 will be made out of a plastic which has a melting temperature above 137 degrees Celsius so that the sheath 20 may be for autoclaved. The sheath plastic should also be somewhat elastic (to allow insertion and removal from the syringe), and relatively cheap and easy to manufacture. The presently preferred plastic is nylon. The sheaths 20 are disposable (after multiple uses). New sheaths can be bought separately.

Needle 31 has a point 34.

Needle 31 and point 34 are supplied covered by a safety cap 38, protecting a user from the point 34 of needle 31.

Syringe body 9 comprises a spiral groove or grooves 39, in a grooved part 40 of syringe body 9. The groove is preferably on a cylindrical part of an outside surface of the syringe body 9. The groove is spiral.

Figs 1 , 4, 5 & 6, & 10 show front views of sheath 20. Sheath front 42 (fig. 10) has a left side 42L and right side 42R. Front 42 is open at varying widths at 43-44 (fig. 10); 45 & 46 (fig. 9).

In fig. 4, internally threaded sheath 20, snaps and/or screws by threads 50, in segments 51-57; on to grooves 39, shown in fig 2 front elevation; in fig. 3 side elevation; and fig. 5 exploded view. Fig. 2 is a front elevation of the tip-ward end of the syringe 5 syringe body 9, without the sheath. Syringe front walls 102L & 102R are separated by a front gap 64 to allow the needle assembly 14 to be inserted.

In the photos that were figs. 2 & 19 of the Provisional Application 62/118,310, a nonfunctional piece of paper was placed against the back-wail so the front walls 102L & 102R and gap 64 could be seen in fig. 19 without being confused by back wall reflections of the stainless steel syringe body 9.

Fig. 3 is a side elevation of the tip-ward end of the syringe 5 including syringe body 9, without the sheath. Grooved part 40 comprises groove 39. Groove segments 91 -97 are separated by lands 111-119.

Fig. 4 is a front elevation of sheath 20, which sheath 20 will be made out of either plastic or metal and clipped onto the syringe. The presently preferred embodiment is clear nylon with a wall thickness of 1.2 mm. it is softer than the metal syringe, and elastically flexible, so that it springs open and closed a little. The sheath must be autoclavable. The front 42 of sheath 20 is open at gaps of varying widths at 43, 44 (fig. 10), 45 to 46 (fig. 9), to allow needle assembly 14 to be inserted into the syringe body 9 from the front.

A protruding thread 50, matches the groove 39 (fig. 5) on the grooved part 40 of syringe body 9.

As on fig. 4, thread 50 begins ring-ward at segment 51 on front-wall 42L, is interrupted at gap 43, continues at segment 52 continuously around the back-wall 42B as segment 53, continues continuously as segment 54 around inside the front-wail 42L, is interrupted at gap 43, continues at segment 55 continuously inside the front-wall 42R, continuously around the back-wall 42B as segment 56, continues continuously as segment 57 around inside the front-wail 42L, and segment 57 ends at the gap at 44, the tip-ward end of thread 50.

Fig. 5 shows corresponding groove segments 91 , 92, 94, 95, 97 on syringe body 9.

Grooves 91-97 divide lands 111 , 112, 114, 115, 117, 118, 119, the raised parts between the depressed groove segments 91-97.

Sheath 20 should be installed on syringe 5 syringe body 9, first. This can be done by:

Placing sheath 20 needle ward of conical part 16, and spinning sheath 20 in a tightening direction until thread 50 grabs groove 39 and continuing to tighten, past some stops, until a stop at the position shown in figs. 1 & 6.

Or:

Placing sheath 20 tip-ward of conical part 16; and pushing down on tip 107 of sheath 20. Thread segment 51 rides over land 117, to snap into groove 94 while thread segment 52 rides over land 115, to snap into groove 92.

A further push on tip 107 causes: thread segment 51 to ride over land 114, to snap into groove 91 , while thread segment 52 rides over land 115, to snap into groove 92; while thread segment 54 rides over land 117, to snap into groove 94, while thread segment 55 rides over land 115, to snap into groove 92.

Sheath 20 is now positioned as shown in figs. 1 & 6, ready to receive the needle assembly 14.

This sheath 20 will allow the insertion of a needie assembly 14, in the sheath 20's resting position, shown in figs. 1 & 6. Needle cone 15 is inserted through gap 45 of sheath 20, to seat against the inside 140 of syringe cone 16.

Fig. 6 is a front elevation of the syringe, sheath in position to receive a needle assembly, and a needle assembly, placed in the syringe, but not yet secured. A cartridge ejection slot 278 is provided.

In fig. 1 , to eject a medicine cartridge 12: withdraw actuator-ring 7, and harpoon 1 ring-ward; turn the syringe front-down over a waste container; and push a finger through cartridge ejection slot 278 against the medicine cartridge 12, untii it falls out the long opening 122 on the front of syringe body 9 (fig. 1 ). To remove a needle assembly 14, reversing rotation of the sheath 20 will relieve the seating pressure and allow the needle assembly 14 to fall directly from the syringe into a sharps container by inverting the syringe (over the sharps container).

At this point it's useful to fully describe and show the details of the presently preferred sheath 20.

Fig. 7 is a slightly oblique top perspective view of sheath 20, looking in a ring-ward direction. Finger ribs 141 & 142, on the outside of sheath 20, assist the dentist in rotating the sheath by providing grip. Tip-ward end 21 is the surface which pushes against (fig. 1 ) flange 22 on a cylindrical portion 27 of needle assembly 14.

Fig. 8 is a bottom plan view of sheath 20, looking in a tip-ward direction, internal stops 151 & 152 cooperate with surfaces and grooves on the syringe 5 to stop rotation of sheath 20 at various angles to syringe 5.

Fig. 9 is a front oblique view of sheath 20. This conveys the ramped and angled shape of stop 151. The angled surfaces of stop 151 , include stop 151 's front surface 151 F, inside 153, and top 154. Sheath 20 has an inside wall 157.

Smaller stop 152 is seen through the translucent wall of sheath 20, as are thread segments 52, 53, and 56.

Fig. 10 shows clearance 155 between inside wall 157 of sheath 20, and outside of conical wall 16 of syringe 5. In the position shown in fig. 10, when the sheath 20 is being rotated onto syringe 5, and the lowest segment of the thread is engaged with the highest groove of the syringe 5, there is sufficient clearance 155 so that inside surface 153 of stop 151 almost clears the outside surface 16 of syringe 5, and provides only a gentle stop. Rotating sheath 20 tighter, expands flexible sheath 20, and allows sheath 20 to rotate another revolution, and ring-ward.

Because surface 157 approaches surface 16, the rotation becomes stiffer, until stop 151 (fig. 11 ) drops into gap 200 (fig. 12), at edge 201 , at which point resistance drops.

At fig. 13, topmost thread segment 58's leading point 214 (fig. 13), is traveling along groove segment 95 (Fig. 12). But, leading point 214 encounters a constricted end 215 of groove 95, providing a low-resistance stop.

Increasing rotation force will force the sheath 20 to rotate again and accelerate briefly, as stop 152 (fig. 8) drops into gap 200 (fig. 12).

But, there is only about one millimeter of play before stop 151 stops hard against edge 160 (figs. 2 & 3). This centers sheath 20, so that sheath front wall gap 56 aligns with syringe front wall gap 64, (figs. 1 & 6) so that the needle assembly 14 can be inserted into the cone 16.

After insertion of the cone 15, this sheath 20 will be rotated 180 degrees so that the incline of thread 50 and grooves 39 push the needle assembly 14 needle-ward, to the position shown in fig. 11 , thereby seating a conical segment 15 of the needle assembly 14, against a cooperatively shaped conical part 140 of the interior of the syringe's cone 16.

Fig. 22 shows how the top, or tip, or end 107 of sheath 20 abuts and pushes against flange 22 of needle assembly 14, thus seating needle's cone 15, firmly against the inside of syringe cone 16. Sheath 20 will thus stabilize the needle assembly 14, and thereby facilitate installation of anesthetic medicine cartridges 12, and facilitate changing anesthetic medicine cartridges 12 during multiple injections.

Further tightening rotation of the sheath 20 will cause the flexible sheath's threads to jump the grooves on the syringe, allowing sheath 20 to move one groove ring-ward, and thereby relieve the seating pressure, and thereby allowing the needle assembly 14 to fall from the syringe 5 into a sharps container, not shown.

Alternatively, reversing rotation, to a loosening rotation of sheath 20, will relieve the seating pressure and allow the needle to fall from the syringe into a sharps container.

This sheath can be made out of stainless steel sheet to meet the above criteria. The stainless steel sheet can remove the chrome plating after multiple uses; therefore, there must be no sharp edges to remove chrome plating.

Fig. 13 shows multiple grooves to stabilize of the sheath on the syringes to allow forward rotation (the activated position) and backward (the resting position). I have tried the grooves in the cone section of the syringes; however, the grooves in the cone section do not add to the stability. These grooves should not hinder the placement (or removal) of cartridges; therefore, the grooves should not be placed below the ribbon part of the syringe.

Fig. 14 is a front elevation of an early embodiment of syringe body, generally

designated 9, with threads running onto the cone.

Dimensions are provided in millimeters (mm). Body 9 has a tip-ward surface 225 measuring 5.2 mm across its outer diameter. Threads 227 at the bottom or ring-ward end of syringe body 9 can screw into finger grip 8 (fig. 1 ), to assemble syringe body 9 to finger grip 8.

A 24.8 mm long slot 278 is provided, so that the user can change medicine cartridge 12 by: withdrawing the harpoon 11 Fig. 19, by pulling down (ring-ward) the shaft 10 13, pulled back by actuator ring 7 (fig. 1 ); pushing a finger through ejection slot 278 from the back of syringe body 9 (figs 14 & 19) against medicine cartridge 12 (fig. 1 ); placing the thumb of the same hand as the finger against the front of medicine cartridge 12, to grasp medicine cartridge 12; sliding medicine cartridge 12 ringward or away from cartridge needle 231 and out front opening 280, to free medicine cartridge 12 from cartridge needle 231.

Figure 14 is a front elevation of syringe 5 syringe body 9, showing slot 278, and dimensions in mm.

Figure 15 is a top plan view of syringe body 9, showing top surface 225 of syringe body 9.

Figure 16 is a top plan view of sheath 20. Figure 17 is a front elevation of sheath 20. Figure 18 is a bottom plan view of syringe body 9, showing threads to mount the finger grip 8.

Figure 19 is a front elevation of said syringe body 9 with plunger shaft 10 mounted on syringe body 9.

A collar 228 extends tip-ward from the syringe body 9. The collar 228 has a tip-ward edge 225.

A front collar opening 226 has a width 226A equal to the inner diameter of the collar 228. The front collar opening 226 extends the axial length 226B of the collar 228.

Figure 20 is a perspective view of a needle assembly 14. The needle assembly 14 is assembled. When the needle assembly 14 is assembled, protective cap 38 protects needle 31 , to prevent needle 31 from stabbing a user accidentally.

Figure 21 A shows needle assembly 14 is in three pieces on the right. Needle 31 is part of a needle tube 14A.

The opposite end of needle tube 14A is a second needle or cartridge needle 231 in fluid communication through needle tube 14A with needle 31 , at the ring-ward end of needle assembly 14, under protective cap 238, when assembled.

Cartridge needle 231 is exposed, when uncapped, so that it may impale a diaphragm 301 , atop cap 303 at a tip-ward end of medicine cartridge 12, establishing fluid communication from the medicine cartridge to the hollow needle tube 14A.

Needle tube reinforcement 14B reinforces needle tube 14A. Cylinder 240 reinforces the needle tube 14A at its cartridge-ward end. A second cylinder 244 is tip-ward of cone 15. This cylindrical form 244 carries up to its terminus at 248 where needle 31 is bare. A flange 22 is provided, for sheath 20's pushing against, as in figure 22. In fig. 20, a plurality of six fins 251 reinforces structure 244 and flange 22. Fins 251 provide a snug fit to protective cap 38.

When cap 238 is in its protective position: the widest part of cone 15 fits snugly against cap 238 in place; and

238's rim 260 abuts against a flange 22.

From needle-ward, in a plan view, the six fins 251 resemble an asterisk.

To install the needle assembly 14 onto the syringe, sheath 20 is snapped onto syringe body 9, as in figure 6, and syringe front walls 102L and 102R are aligned with sheath front walls 42L & 42R, to allow needle 231 of needle assembly 14 to pass through the gap formed between the left and right front walls of the sheath and the syringe.

Lower or ring-ward protective cap 238 is removed from lower or ring-ward needle 231 to expose ring-ward cartridge needle 231. The needle assembly 14 is placed with its cone 15 through the aligned front openings of syringe and sheath, with conical portion 15 of the needle assembly 14. Conical portion 15 is then seated inside the matching conical end 16 of syringe body 9, as in figures 1 and 6.

Sheath 20 is then rotated in a clockwise direction, when viewed from the actuator ring 7, to be positioned as in fig. 22, causing end 107 of sheath 20 screw to needle-ward, against flange 22, forcing the needle assembly 14, still-capped by needle-cap 38, needle-ward, so that cone 15 seats firmly against the inside of syringe cone 16, holding the needle assembly 14 firmly in place in the syringe body 9. The front gap of the sheath 20 is now aligned diametrically opposite to the front gap of syringe body 9, which closes the front opening 280. in the presently preferred embodiment, this is a 180 degree rotation from the open position.

Thumb ring 7 (fig.1 ) is then pulled down to clear the harpoon 11 (figs.1 & 19), from the compartment 270 for the medicine cartridge 12, thus providing room for the medicine cartridge 12 to be inserted through opening 280 (fig. 19).

Through the front opening 280 of compartment 270 (figure 14 & 19), medicine cartridge 12 is then installed, and positioned as shown in Fig. 1.

Thumb ring 7 is then pressed by the user, down towards the needle; driving shaft 10 and harpoon 11 into plunger 13 (fig. 21 ) of medicine cartridge 12;

driving the medicine cartridge 12 toward the needle assembly 14; and impaling the tip-ward diaphragm 301 , located atop cap 330 of the medicine cartridge 12, by impaling the tip-ward diaphragm 301 on aft needle 231 of fig. 20; and creating fluid communication between the medicine in medicine cartridge 12 and the hollow needle 31 and its hollow point 311 at tip 34.

Medicine cartridge 12 may thereafter be changed for this patient. Thumb ring 7 is withdrawn as far as possible which pulls harpoon 11 out of plunger 13 and provides clearance of the cartridge, probably disengaging the cartridge from aft needle 231. If the cartridge as not come loose of aft needie 231 , the cartridge is grasped between a thumb (through opening 280) and forefinger (through opening 278), and pulled back from aft needle 231. Syringe 5 can then be turned front side down. Medicine cartridge 21 will then fall through opening 280 out of compartment 270.

A new medicine cartridge 12 may then be inserted as described above.

When the patient is done being anesthetized, the last cartridge can be removed, sheath 20 can be rotated in either direction, which will either: twist sheath 20 away from flange 22 on needle assembly 14; or allow with threads to jump next lower groove segment.

Either way, the pressure holding the flange 22 needle-ward, and holding cone 15 in its seat 16, is relieved. Then the syringe can be turned, front-down, allowing the needle assembly 14 to drop out of the syringe 5 into a sharps container.

The Slope Of The Grooves.

The limitation of the activation position will be when the sheath 20 pushes the needle assembly 14 against the end of the syringe 5. But the slope of the grooves has to be such that, for a 120 degree rotation, the forward, or needle-ward, traveling length (from the resting to the activated position) is about 1.8 - 2.0 mm.