JP2000102606A - Cartridge dental injector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To linearly and straightly push a plunger rubber without adding eccentric stress to a glass tube and to improve a property for use by providing a spherical projection at the center of an interior of a cap for assembling an injection needle and by concentrically deforming an aluminum cap with a round hole of a cartridge. SOLUTION: A cartridge 19 including a glass tube 21 enclosing fluid for injection is assembled to a cylindrical body 1 of an injector, and a dicephalous injection needle is assembled to a cap 2 in a state held by the cap 2 and a tube 5 for pushing a core compressed by a spring. After a rubber stopper of an edge section of the cartridge 19 is penetrated by one tip of the injection needle to communicate with the fluid for injection, when fingers are put on a pulling lever 3 and a pushing lever 7 is pushed by a palm, a plunger 8 pushes a plunger rubber 25 to pour out the fluid for injection from the needle. At this time, since an aluminum cap covering a tip of the plunger 19 is pushed by attaching to a spherical recess section of an interior of the cap 2 to become concentric to be fixed, the plunger rubber 25 is straightly slid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cartridge type dental syringe in which a cartridge filled with an injection solution such as an anesthetic solution is loaded to perform an injection operation.

[0002]

2. Description of the Related Art A dental syringe of this kind is basically composed of
A cylindrical main body, a needle mounting base screwed to a tip of the main body, a pull lever fixed to a rear portion of the main body, a spring-biased centering tube in a bore of the cylindrical main body, and a core. A plunger extending through the exit tube and having a plunger head at a distal end and a push lever at a rear end. The cylindrical body has a window for inserting the cartridge containing the injection solution into the bore, and the inner diameter of the bore of the body is slightly larger than the outer diameter of the cartridge. As is well known, the cartridge holds a rubber stopper that seals the tip of the glass tube, has an aluminum cap having a circular hole at the center to expose a part of the rubber stopper, and is fitted into the rear end of the glass tube. It contains a plunger rubber for pushing out the injection solution enclosed in the inside. When the cartridge is loaded into the syringe, the cartridge is securely held between the base and the centering tube. Attach the double-ended injection needle to the base, insert the needle on the rubber stopper side into the rubber stopper to communicate with the injection solution in the cartridge.At this stage, put your finger on the pull lever and press the push lever with the palm, and the plunger will Move and push the plunger rubber. In dental oral care, it is experienced that the force required to push the injection solution in the cartridge at the time of injection must be quite large.

[0003]

There are several problems with the syringe having such a configuration. One of them is related to the accuracy of the syringe. However, when the plunger presses the plunger rubber in a biased manner, a large bias is applied to the glass tube constituting the cartridge, and the glass tube is rarely broken. That is. Secondly, when the centering tube is retracted during loading and positioning of the cartridge, or moves forward due to the bias of the spring, a large surface contact between the centering tube and the inner surface of the main body bore generates an abnormal friction sound. And this was transmitted to the hands as discomfort. SUMMARY OF THE INVENTION It is an object of the present invention to eliminate all of the above disadvantages and to provide a very ideal cartridge type dental syringe.

[0004]

According to the present invention, there is provided a cylindrical main body, a needle mounting base screwed to a tip of the main body, a pull lever fixed to a rear portion of the main body, and a bore of the cylindrical main body. And a spring-biased centering tube, a plunger extending through the centering tube and having a plunger head at a distal end and a push lever at a rear end. A window for inserting the cartridge enclosing the cartridge into the bore is provided, the inner diameter of the bore of the main body is slightly larger than the outer diameter of the cartridge, and the cartridge loaded into the bore of the cylindrical main body through the window is a base. And a plunger head which presses the plunger rubber of the cartridge with the plunger head. Tsu provided spherical convex portion which concentrically deform the flop, to provide a cartridge type dental syringe, characterized in that the formation of the plunger rubber in contact with the surface of the plunger head as convex spherical surface.

Further in accordance with the present invention, the centering tube includes a cup having a receptacle for receiving the plunger head, the outer cylindrical surface of the cup minimizing contact with the inner surface of the bore of the cylindrical body. For this reason, it is preferable to form it as a middle and high arcuate outer surface.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1 and 2, there is shown a perspective view of a cartridge type dental syringe in its entirety. The syringe has a cylindrical main body 1 and a needle mounting screwed to a tip of the main body. Base 2 and pull lever 3 fixed to the rear of the body
A spring-biased centering tube 5 in the bore 4 of the cylindrical body 1, a plan extending through the centering tube 5 and having a plunger head 6 at the tip and a push lever 7 at the rear end. A jar 8. As shown in detail in FIG. 2, the pull lever 3 is fixed to the cylindrical body 1 by holding the shoulder 10 of the bore 9 of the pull lever 3 against the rear end surface of the cylindrical body 1. This is achieved by screwing the nut 11 into the rear inner surface of the cylindrical body 1. Holding nut 1
1 also serves to slidably receive the rear end of the centering tube 5 and to support it centered. The spring bias of the centering tube 5 is
The centering tube 5 is moved by a coil spring 13 disposed between an annular spring receiver 12 and an inner end surface of the nut 11 formed substantially at the center of the centering tube 5. The cup 14 formed at the tip of the
Is limited by contact with the shoulder 15 of the person. Cup 1
4 has a receptacle 16 for receiving the plunger head 6, the tip of which is preferably formed with an annular inclined surface 17; When the plunger 8 is pulled rearward with respect to the main body 1, the head 6 comes into contact with the annular shoulder 18 of the receptacle 16, and the centering tube 5 can be retracted against the action of the coil spring 13. The cylindrical main body 1 is provided with a window 20 for inserting a cartridge 19 containing an injection solution into the bore 4 thereof. The inner diameter of the bore 4 of the main body is slightly larger than the outer diameter of the cartridge 19.

As clearly shown in FIGS. 3 and 4,
As is well known, the cartridge 19 has an aluminum cap 24 that holds a rubber stopper 22 that seals the tip of the glass tube 21 and has a circular hole 23 that exposes a part of the rubber stopper 22 at the center. It includes a plunger rubber 25 that is fitted into the end and pushes out the injection solution enclosed in the cartridge. To load the cartridge into the syringe, the syringe is turned obliquely upward and the cartridge is inserted into the bore 4 of the main body 1 through the window 20 from the plunger rubber 25 thereof. In this state, the aluminum cap 24 at the end of the cartridge is caught by the edge of the window 20 and stands by at an angle to the main body. When the plunger 8 and the centering tube 5 are retracted, the cartridge 19
Moves into the bore 4 by its own weight and finally falls through the window 20 into the bore 4. When the plunger 8 is released, the centering tube 5 moves forward by the action of the coil spring 13 and the glass tube 2 of the cartridge is set on the annular inclined surface 17 of the cup 14.
Press 1 to securely hold the cartridge 19 between the base 2 and the centering tube 5.

The base 2 has a cartridge 1 at its center.
9 is provided with a spherical convex portion 26 acting on the rubber stopper 22 to the aluminum cap 24, and the plunger head 6 has a convex spherical surface on its distal end surface which presses the plunger rubber 25 at its center. 27. The outer cylindrical surface of the cup 14 of the centering tube 5 is formed as a middle and high arcuate outer surface 28 in order to minimize the contact with the inner surface of the bore 4 of the main body 1. As described above, in a state where the cartridge 19 is loaded in the syringe and held by the base 2 and the centering tube 5 biased by spring, the double-ended injection needle is loaded into the base 2 and one of the needle tips is inserted. The rubber stopper 22 of the cartridge is pierced to communicate with the injection solution, and then the finger is pulled on the lever 3 and the push lever 7 is strongly pushed with the palm. The plunger 8 pushes the plunger rubber 25 to push the injection solution from the needle. Release. In the initial stage of such an injection operation, when the injection solution filled in the cartridge is subjected to an extruding pressure by the plunger rubber 25, the aluminum cap 24 is pressed against the spherical convex portion 26, and the circular hole 23 of the cap 24 is It deforms concentrically inward, which causes the cartridge to swing slightly and lock in the center of the bore. On the other hand, during the injection operation, a slight convex spherical surface of the plunger head 6 of the plunger 8 causes pressure to be applied to the plunger rubber 25 at its center, and as a result,
The plunger rubber 25 is pressed straight and straight without applying a partial stress to the glass tube. In addition, when the centering tube 5 is pulled back by the plunger 8 or advanced by the coil spring, the centering tube 5 slides smoothly without frictional resistance due to the minimum contact with the inner surface of the main body bore, so that the conventional case is achieved. It emits strange strange friction sounds and unpleasant rough feeling transmitted to hands,
There is no slight intermittent sliding resistance.

[Brief description of the drawings]

FIG. 1 is a perspective view of a cartridge type dental syringe according to the present invention.

FIG. 2 is a partial cross-sectional side view of a cartridge-type dental syringe according to the present invention.

FIG. 3 is an enlarged cross-sectional view taken along line AA of FIG.

FIG. 4 is an enlarged sectional view taken along line BB of FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylindrical main body 2 Cap 3 Pull lever 4 Bore 5 Centering pipe 6 Plunger head 7 Push lever 8 Plunger 14 Cup 16 Receptacle 19 Cartridge 20 Window 22 Rubber stopper 23 Circular hole 24 Aluminum cap 25 Plunger rubber 26 Spherical convex part 27 convex spherical surface 28 middle and high arcuate outer surface

Claims (2)

[Claims] 1. A cylindrical main body, a needle mounting base screwed to a tip of the main body, a pull lever fixed to a rear part of the main body, and a spring-loaded core in a bore of the cylindrical main body. A cylindrical body for inserting a cartridge enclosing the injection solution into its bore, including a centering tube and a plunger extending through the centering tube and having a plunger head at a distal end and a push lever at a rear end. The inner diameter of the bore of the main body is slightly larger than the outer diameter of the cartridge, and the cartridge loaded into the bore of the cylindrical main body through the window is held between the base and the centering tube. In a dental syringe in which a plunger rubber of a cartridge is pressed by a plunger head, a spherical convex for concentrically deforming a rubber stopper and an aluminum cap with a circular hole of the cartridge is provided in the center of the inside of the base. A cartridge-type dental syringe, wherein a surface of the plunger head in contact with the plunger rubber is formed as a convex spherical surface. 2. The centering tube comprises a cup having a receptacle for receiving a plunger head, the outer cylindrical surface of the cup being a mid-high arcuate outer surface to minimize contact with the inner surface of the bore of the cylindrical body. The cartridge-type dental syringe according to claim 1, wherein the syringe is formed.