Needleless syringe

A needleless syringe comprising:

• a body;
• a solenoid coil wound on an outer circumferential surface of the body;
• a cylinder coupled to the body to be in communication with an open front surface of the body and comprising a drug accommodating portion in which the drug is accommodated, and a nozzle portion injecting the drug accommodated in the drug accommodating portion forward;
• a moving magnetic body that is long inserted into the body in a longitudinal direction and reciprocates forward and backward by a magnetic force generated when a current is applied to the solenoid coil;
• a stationary magnetic body that is inserted behind the moving magnetic body inside the body and has magnetism by a magnetic force generated when a current is applied to the solenoid coil and is fixed;
• a piston that is inserted in front of the moving magnetic body inside the body and pressurizes the drug in the drug accommodating portion by an impulse applied by forward movement of the moving magnetic body when the moving magnetic body moves forward;
• a nozzle portion opening/closing valve that is provided to open/close a passage hole between the nozzle portion and the drug accommodating portion;
• and
• a forward/backward driving unit that repeats the supply and cut-off of current to the solenoid coil at a preset period, thereby repeating the forward movement and the backward movement of the piston,
• wherein the solenoid coil comprises:
• a first coil, which is wound on front of the outer circumferential surface of the body, to which a current is applied during forward movement of the piston and generates a magnetic force in a forward movement direction of the moving magnetic body;
• and
• a second coil, which is wound on rear of the first coil on the outer circumferential surface of the body, to which a current is applied during backward movement of the piston and which generates a magnetic force to magnetize the stationary magnetic body, and
• the forward/backward driving unit comprises:
• a current supply unit that repeatedly supplies a current to the first coil to move the moving magnetic body forward and cuts off supply of current to the second coil during forward movement of the piston and that repeatedly cuts off supply of current to the first coil and supplies a current to the second coil to move the moving magnetic body backward due to the magnetic field of the stationary magnetic body during backward movement of the piston;
• and
• the current supply unit applies a current to the first coil for a first preset time and then cuts off supply of current, and a mass of the moving magnetic body is 100 g or less, and the first preset time is set to be 80 ms or less.

A needleless syringe comprising:

• a body;
• a solenoid coil wound on an outer circumferential surface of the body;
• a cylinder coupled to the body to be in communication with an open front surface of the body and comprising a drug accommodating portion in which the drug is accommodated, and a nozzle portion injecting the drug accommodated in the drug accommodating portion forward;
• a moving magnetic body that is long inserted into the body in a longitudinal direction and moves forward by a first magnetic force generated when a current is applied to the solenoid coil;
• a stationary magnet that is inserted behind the moving magnetic body inside the body and has a second magnetic force to pull the moving magnetic body when supply of current to the solenoid coil is cut off, to move the moving magnetic body backward;
• a piston that is inserted in front of the moving magnetic body inside the body and pressurizes the drug in the drug accommodating portion by an impulse applied by forward movement of the moving magnetic body when the moving magnetic body moves forward;
• a nozzle portion opening/closing valve that is provided to open/close a passage hole between the nozzle portion and the drug accommodating portion;
• and
• a forward/backward driving unit that repeats the supply and cut-off of current to the solenoid coil at a preset period, thereby repeating the forward movement and the backward movement of the piston,
• wherein the forward/backward driving unit comprises:
• a current supply unit that repeatedly supplies a current to the solenoid coil to generate the first magnetic force greater than the second magnetic force during forward movement of the piston and repeatedly cuts off supply of current to the solenoid coil during backward movement of the piston.

A needleless syringe comprising:

• a body;
• a solenoid coil wound on an outer circumferential surface of the body;
• a cylinder coupled to the body to be in communication with an open front surface of the body and comprising a drug accommodating portion in which the drug is accommodated, and a nozzle portion injecting the drug accommodated in the drug accommodating portion forward;
• a moving magnetic body that is long inserted into the body in a longitudinal direction and moves forward by a first magnetic force generated when a current in a preset first direction is applied to the solenoid coil;
• a stationary magnet that is inserted behind the moving magnetic body inside the body and has a second magnetic force to pull the moving magnetic body when supply of current to the solenoid coil is cut off, to move the moving magnetic body backward;
• a piston that is inserted in front of the moving magnetic body inside the body and pressurizes the drug in the drug accommodating portion by an impulse applied by forward movement of the moving magnetic body when the moving magnetic body moves forward;
• a nozzle portion opening/closing valve that is provided to open/close a passage hole between the nozzle portion and the drug accommodating portion;
• and
• a forward/backward driving unit that repeats the supply and cut-off of current to the solenoid coil at a preset period, thereby repeating the forward movement and the backward movement of the piston,
• wherein the forward/backward driving unit comprises:
• a current supply unit that repeatedly supplies the current in the first direction to the solenoid coil to generate the first magnetic force greater than the second magnetic force during forward movement of the piston and repeatedly supplies a current in a second direction opposite to the first direction to the solenoid coil during backward movement of the piston.