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Publication numberUS3605745 A
Publication typeGrant
Publication dateSep 20, 1971
Filing dateDec 15, 1969
Priority dateDec 15, 1969
Publication numberUS 3605745 A, US 3605745A, US-A-3605745, US3605745 A, US3605745A
InventorsHodosh Milton
Original AssigneeHodosh Milton
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Dental injection apparatus
US 3605745 A
Abstract  available in
Previous page
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Claims  available in
Description  (OCR text may contain errors)

Sept. 20, 1971 M. HODOSH DENTAL INJECTION APPARATUS Filed Dec. 15, 1969 INVENTOR HODOSH BY T (9 ATTORNEYS United States Patent 3,605,745 DENTAL INJECTION APPARATUS Milton Hodosh, 72 Overhill Road, Providence, RI. 02906 Filed Dec. 15, 1969, Ser. No. 884,962 Int. Cl. A61m 5/20 US. Cl. 128-218A 5 Claims ABSTRACT OF THE DISCLOSURE Apparatus for slowly and uniformly injecting liquid anesthesia and the like comprising a syringe having a compressible cartridge therein containing the anesthesia, and piston and cylinder means for effecting compression of the cartridge to cause the desired dispensing of the anesthesia, said apparatus comprising a supply of a viscous fluid, such as hydraulic oil, which is forced into said cylinder through a port located on one side of the piston and is forced out of the cylinder through a port located on the opposite side of the piston, whereupon movement of the piston is cushioned by the viscous fluid.

BACKGROUND OF THE INVENTION During certain surgical and dental procedures, and particularly the latter, it is common practice to administer an anesthetic, such as novocaine, in order to temporarily deaden sensitive nerves so that the patient will not be compelled to endure undue pain. However, the administration of the anesthetic, in and of itself, is frequently unpleasant and somewhat painful to the patient, and it has been found that the primary cause of the pain and discomfort attendant to the administration of a liquid anesthetic, such as novocaine, is the fact that conventional injection apparatus administers the anesthetic too quickly and without suflicient uniformity. It has been found that if the anesthetic is administered slowly and uniformly, almost on a drop-by-drop basis, no pain or discomfort results.

It is not possible, however, to administer the anesthetic slowly enough and with sufficient uniformity where a hand syringe is used, or wherever presently known injection apparatus is utilized. It is therefore a primary object of this invention to provide apparatus that will administer a liquid anesthetic with extreme slowness and uniformity and wherein the dispensing of the anesthetic is in no way dependent upon the manual dexterity of the person administering same.

SUMMARY OF THE INVENTION As previously stated, the basic concept of this invention is the provision of apparatus that will slowly and smoothly administer an anesthetic. The apparatus generally comprises a syringe having therein a collapsable cartridge which houses the anesthetic that is to be dispensed or injected. A conventional hyperdermic needle is in communication with the cartridge and extends outwardly from the syringe so that as the cartridge is compressed, the anesthetic will be dispensed through the needle.

In order to effect extremely slow and uniform compression of the cartridge, the syringe embodies a cylinder which contains a relatively viscous fluid, such as hydraulic oil or the like. A reciprocal piston is located in the cylinder and has means engaging the cartridge to effect col lapsing thereof in response to movement of the piston. A viscous fluid is introduced to the cylinder on one side of the piston and is simultaneously exhausted from the cylinder on the opposite side of the piston, the piston will be caused to move, all in a well-known manner, but the fact ice that the piston is moving in a highly viscous fluid permits the desired slow and uniform movement of the piston to take place. The apparatus further comprises a pair of cylinders having oppositely acting pistons which function to force fluid into the syringe cylinder on one side of the piston and at the same time permit exhausting of the fluid from the opposite side thereof. Movement of these oppositely acting pistons is achieved by a secondary fluid that has relatively little or no viscosity, such as air, for example. Thus, the apparatus is basically actuated by compressed air, but the compressed air, in turn, forces a viscous medium, such as a hydraulic oil or the like, into the syringe cylinder to achieve extremely slow and uniform movement of the syringe piston.

Other objects, features and advantages of the invention shall become apparent as the description thereof proceeds when considered in connection with the accompanying illustrative drawings.

DESCRIPTION OF THE DRAWINGS In the drawings which illustrate the best mode presently contemplated for carrying out the present invention:

FIG. 1 is a schematic flow diagram showing my apparatus in the non-operative position thereof;

FIG. 2 is a schematic flow diagram showing the apparatus in operative position.

DESCRIPTION OF THE INVENTION Referring to the drawings, there is shown generally at 10 our injection device comprising a syringe 12 having a fixed partition 14- therein defining a dispensing chamber 16 and a fluid chamber 18. A compressible cartridge 20 is located in dispensing chamber 16 and has a conventional hyperdermic needle 22 interengaged therewith. The syringe 12 has an opening 24 through which needle 22 passes, it being understood that when the cartridge 20 is compressed, by means hereinafter to be described, the anesthesia or other material contained within the cartridge will be dispensed through the needle. A piston 26 having a piston shaft 28 is positioned in the fluid chamber 18. The shaft 28 passes slidingly and sealingly through an aperture 30 in the partition 14 and has at its extremity a pusher 32 which engages the catridge 20 to compress same when piston 26 is moved from the position illustrated in FIG. 1 to the position illustrated in FIG. 2.

The apparatus 10 further comprises a pair of cylinders, 34, 36 having oppositely acting pistons 38, 40 respectively, mounted therein for reciprocal movement. A conduit 42 communicates with cylinder 34, as at port 44, at one of its ends and with fluid chamber 18, as at port 46, at its opposite end. Likewise, conduit 48 communicates with cylinder 36 at one of its ends, as at port 50, and with fluid chamber 18 at its opposite end, as at port 52. It will be noted that port 46 is located adjacent one extremity of fluid chamber 18 while port 52 is located adjacent the opposite extremity thereof.

It will therefore be seen that the portions of cylinders 34 and 36 located to the right of pistons 38 and 40, when viewing FIG. 1, along with fluid chamber 18 and interconnecting conduits 42 and 48 constitute a closed system which is filled with a relatively viscous fluid, such as hydraulic oil or the like. When piston 38 is moved from the position of FIG. 1 to the position of FIG. 2 it will be apparent that the viscous fluid in the system will be forced through conduit 42 through port 46 to fluid chamber 18 on the backside of piston 26 thus causing the piston 26 to move to the position illustrated in FIG. 2. As piston 26 commences to move, its shaft 28 slidingly moves through partition 14 thereupon pusher 32 causes the cartridge 20 to compress. This in turn dispenses the contents of cartridge 20 through needle 22. Dueto the highly viscous nature of the fluid in the system, the movement of piston 26 is extremely uniform and may be regulated so as to move extremely slowly. In etfect, the viscous fluid acts as a cushion in the system which imparts the desired uniformity and slowness to the movement of piston 16. Regulating valves 54 and 56 are located in conduits 42 and 48 respectively to afford some degree of control over the rate of flow of the fluid in the system and hence the rate at which the anesthesia is dispensed. In addition, a bleed valve 58 is connected to cylinder 36 so that the system may be bled should any air inadvertently become entrapped therein.

Since it is desired to have quickly responsive actuating means for the apparatus 10, the pistons 38 and 40 are actuated by means of air pressure. Thus, any suitable source of compressed air is utilized and the compressed air is fed to conduit 60 through an air pressure regulator 62, and then to a valve 64 having suitable actuating means (not shown) which permits the compressed air to be selectively introduced to conduit 66 or to condut 68. As will be obvious, when valve 64 is actuated to introduce air through conduit 66, the compressed air will enter cylinder 34 at port 70 to cause piston 38 to start moving against the oil pressure in the system until the parts reach the position illustrated in FIG. 2. When it is desired to retract piston 26, valve 64 is actuated to shut off the air flow through conduit 66 and to simultaneously force air through conduit '68 into cylinder 36 via port 72, thus forcing piston 40 to move from the position of FIG. 2 to that of FIG. 1.

It will be understood that although my invention has prime application in the injection of liquid anesthetic, such as novocaine and the like, it is also of value in other applications where an extremely slow and uniform injection is desired. Thus, my apparatus has also proven to be of value when injecting a sealant into a root canal in the course of dental root canal work. It will also be understood that although FIG. 2 shows cartridge 20' completely compressed, the valve 64 may be operated so as to compress the cartridge only to a desired degree at which point the pistons 38 and 40 may be reversed to commence retraction of piston 26.

While there is shown and described herein certain specific structure embodying the invention, it will be manitest to those skilled in the art that various modifications and rearrangements of the parts may be made without departing from the spirit and scope of the underlying inventive concept and that the same is not limited to the particular forms herein shown and described.

What is claimed is:

1. An apparauts for injecting liquid anesthetic and the like comprising a cylinder having closed end walls and a partition therein defining a fluid chamber and a dispensing chamber, a compressibe cartridge having anesthetic therein located in said dispensing chamber, an injection needle in communication with said cartridge and extending outwardly through the end Wall of said dispensing chamber whereby When said cartridge is compressed anesthetic is dispensed through said needle, a piston in said fluid chamber having a shaft extending through an opening in said partition and engaging said cartridge to compress same responsive to movement of said piston, a supply of viscous fluid in said apparatus and filling said fluid chamber, flow ports provided adjacent opposite ends of said fluid chamber, a pressure means connected through one of said ports to cause movement of said piston against the fluid located in said fluid chamber on an opposite side of the piston and to simultaneously force the fluid on the opposite side of the piston out through the other port and move said piston to compress said cartridge, and means connected with said other port counteracting the flow of said fluid out through said other port.

2. In the apparatus of claim 1, said pressure means and counteracting means comprising a pair of oppositely acting pistons and cylinders connnected with said flow ports by conduit means.

3. In the apparatus of claim 2, said conduit means connecting one of said cylinders to one of said ports and the other of said cylinders to the other of said ports, and flow control means in each of said conduits.

4. In the apparatus of claim 2, said oppositely acting pistons being actuated by a low viscosity fluid.

5. In the apparatus of claim 4, said low viscosity fluid being air and said viscous fluid being hydraulic oil.

References Cited UNITED STATES PATENTS 2,888,924 6/1959 Dunmire 128-218D 2,950,717 8/ 1960 Bouet 128-218D 3,424,154 1/1969 Kinsley 12 8-218RX HUGH R. CHAMBLEE, Primary Examiner U.S. Cl. X.R.

Referenced by
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U.S. Classification604/143
International ClassificationA61M5/20
Cooperative ClassificationA61M5/20
European ClassificationA61M5/20