Method and apparatus for controlling the injection rate of a drug solution in a cartridge type motor-driven dental injection syringe
First Claim
1. A method for controlling the injection rate of an anaesthetic solution in a cartridge type motor-driven injection syringe for dental use, the motor-driven injection syringe being so designed that the electric motor is operatively connected through a reduction gear to a rack and pinion to slowly move a plunger rod and hence a plunger rubber in the cartridge, thereby ejecting the anaesthetic solution through an injection needle, characterized in that the electric motor is adapted to be switched stepwise in speed of revolution between the Low, Medium and High Speed, the starter switch is a two-step operable switch including to the first depression for starting the electric motor at the Low Speed and hence, moving the plunger rod so as to push the plunger rubber in the cartridge at the initial “
- Low Speed”
, and the second depression for making the electric motor run at the “
Low Speed”
, “
Medium Speed”
or “
High Speed”
as selected, to move the plunger rod at the “
Low Speed”
, “
Medium Speed”
or “
High Speed”
.
1 Assignment
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Accused Products
Abstract
Disclosed are a method and apparatus for controlling the injection rate of an anesthetic solution in a cartridge type motor-driven injection syringe for dental use, particularly beginning with the “Low” rate injection at the outset, and switching to the “Medium” or “High” injection rate at an arbitrarily selected time in the course of injection.
The speed of revolution of the electric motor is changed among the low, medium and high speed, and a two-step operable type of switch is used as a starter switch 13. The first depression of the starter switch makes the electric motor 9 start at the low speed, thereby making the plunger rubber 5 initially move at the “Low Speed” in the cartridge 6 via the plunger rod 12, and the second depression of the switch makes the electric motor 9 run at the low, medium or high speed, and accordingly the plunger rod moves at the selected “Low Speed”, “Medium Speed” or “High Speed”.
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Citations
2 Claims
-
1. A method for controlling the injection rate of an anaesthetic solution in a cartridge type motor-driven injection syringe for dental use, the motor-driven injection syringe being so designed that the electric motor is operatively connected through a reduction gear to a rack and pinion to slowly move a plunger rod and hence a plunger rubber in the cartridge, thereby ejecting the anaesthetic solution through an injection needle, characterized in that the electric motor is adapted to be switched stepwise in speed of revolution between the Low, Medium and High Speed, the starter switch is a two-step operable switch including to the first depression for starting the electric motor at the Low Speed and hence, moving the plunger rod so as to push the plunger rubber in the cartridge at the initial “
- Low Speed”
, and the second depression for making the electric motor run at the “
Low Speed”
, “
Medium Speed”
or “
High Speed”
as selected, to move the plunger rod at the “
Low Speed”
, “
Medium Speed”
or “
High Speed”
.
- Low Speed”
-
2. An apparatus for controlling the injection rate of an anaesthetic solution in a cartridge type motor-driven injection syringe for dental use, the motor-driven injection syringe comprising a housing with a nose, a cartridge holder to accommodate an anaesthetic solution-filled cartridge having a rubber disc and a plunger rubber fitted therein, the cartridge holder being detachably attached to the nose;
- a double-pointed injection needle detachably attached to the end of the cartridge holder, penetrating the rubber disc;
a plunger rod adapted to be linearly displaced by the rack and pinion operatively connected through a final reduction gear to the electric motor, thereby ejecting the anaesthetic solution from the cartridge through the injection needle, and a starter switch for starting the electric motor, characterized in that the starter switch comprises two switches responsive to first and second depressions for sequential operation, the motor-driven injection syringe further comprises;
a speed selector switch for making a desired selection among the “
Low Speed”
, “
Medium Speed” and
“
High Speed”
to set the electric motor for the desired running speed,a speed changing circuit and a speed control circuit responsive to the first depression of the starter switch to turn on for making the electric motor run at the low speed, and responsive to the second depression to turn on for making the electric motor run at the “
Low Speed”
, “
Medium Speed”
or “
High Speed”
dependent on which circuit the speed selector switch is connected to, the “
Low Speed Circuit”
, “
Medium Speed Circuit”
or “
High Speed Circuit”
.
- a double-pointed injection needle detachably attached to the end of the cartridge holder, penetrating the rubber disc;
Specification