Abstract

Provided is an electric syringe to be used with two kinds of dental anesthetic solution-containing cartridges, wherein the cartridge holder is configured so as to be capable of being used with both cartridges containing 1.0 mL and 1.8 mL of anesthetic solution and the syringe is configured so that the rubber plunger stopper of the 1.8 mL cartridge can be pushed with a push rod of the length necessary for pushing the rubber plunger stopper of the 1.0 mL cartridge. The cartridge holder (4) used in the electric syringe to be used with two kinds of dental anesthetic solution-containing cartridges is configured so as to be usable with both a 1.0 mL cartridge (3b) and a 1.8 mL cartridge (3a). The push rod (6) has a 1.0 mL cartridge-setting position and a 1.8 mL cartridge-setting position that is drawn back from said position so that the movement of the push rod ends at the same position for both the 1.0 mL cartridge and the 1.8 mL cartridge, and comprises: a bottomed sleeve (22), which accepts the back end of the push rod when pushed back from the ending position and when the push rod is in the 1.0 mL cartridge-setting position, is not affected by the back end face of the push rod but when the push rod is pushed back to the 1.8 mL cartridge-setting position, is pushed backward by the back end face of the push rod; and a returning spring (23) for moving the sleeve together with the push rod forward during forward movement of the push rod.

IPC Classes  ?

• A61M 5/24 - Ampoule syringes, i.e. syringes with needle for use in combination with replaceable ampoules or cartridges, e.g. automatic
• A61M 5/20 - Automatic syringes, e.g. with automatically actuated piston rod, with automatic needle injection, filling automatically

Abstract

Provided is an anesthetic solution-filled cartridge-type electric dental syringe, wherein the plunger has been shortened but the plunger can nevertheless be extended to the distance necessary to evacuate the anesthetic solution from the cartridge. The syringe comprises: an extension tube (11) into which a plunger (5) is movably inserted, the extension tube being movably disposed in the through hole (14) of a support block (13) and having racks (15, 15) formed in the side surface thereof that are coordinated with the racks (9) of the plunger; and a means for the plunger to draw the extension tube to engage the racks (15, 15) of the extension tube with a pinion (21) when the plunger reaches the middle of the distance corresponding to the anesthetic solution accommodation length of the cartridge. By the engagement of the racks of the extension tube with the pinion, the plunger moves together with the extension tube for the remainder of the distance corresponding to the anesthetic solution accommodation length of the cartridge.

IPC Classes  ?

• A61M 5/24 - Ampoule syringes, i.e. syringes with needle for use in combination with replaceable ampoules or cartridges, e.g. automatic
• A61C 19/08 - Implements for therapeutic treatment combined with anaesthetising implements
• A61M 5/20 - Automatic syringes, e.g. with automatically actuated piston rod, with automatic needle injection, filling automatically
• A61M 5/315 - PistonsPiston-rodsGuiding, blocking or restricting the movement of the rodAppliances on the rod for facilitating dosing

Abstract

Provided is a cartridge type linear dental electric syringe wherein the advance drive of a push rod is attained by a simple mechanism by arranging in a straight line the drive shaft of a motor with a reduction gear (geared motor), serving as a prime mover, and the push rod.  The cartridge type linear dental electric syringe comprises an externally-threaded push rod (32) arranged non-rotatably and movably in the longitudinal direction so as to be in line with the drive shaft of a motor with a reduction gear (geared motor) (28), a rotary tube (40) being rotated by the drive shaft, a nut (57) pivotally attached to the rotary tube and consisting of a pair of nut halves (56) that are in the shape of an arm and arranged opposite to each other and have internal threads (68) meshing with the external thread (34) of the push rod (32), a lock ring (70) arranged rotatably and movably, in the longitudinal direction, between a backward position where the internal thread of the nut half in the shape of an arm meshes with the external thread of the push rod and a front position where the meshing is released, a pusher pin (75) that is inserted into a cylindrical space (24) and pushed by the end face of a cartridge holder (22) that is coupled with the space (24) in order to move the lock ring (70) from the front position to the backward position, and a coil spring (80) for pushing the lock ring (70) back to the front position when the cartridge holder (22) is not inserted into the cylindrical space, wherein the nut (57) is rotated around the push rod (32) by the rotation of the rotary tube (40) and thereby the push rod (32) is advanced by a screw action.

IPC Classes  ?

• A61M 5/24 - Ampoule syringes, i.e. syringes with needle for use in combination with replaceable ampoules or cartridges, e.g. automatic