Automatic injection device

Abstract

An automatic injection device for providing a injection is disclosed. The device includes a housing having a distal end operable by a user and an open proximal end for placement at an injection site. The device includes a syringe movably disposed in the housing. The syringe includes a needle and substance for injection. The device also includes a plunger that has a continuous length from a first end to a second end and includes an anchoring portion initially engaged with the distal end of the housing in a latched position. The device also includes a biasing mechanism to apply pressure to the plunger when activated and move the plunger towards the proximal end of the housing, and a firing mechanism assembly operable by the user to release the anchoring portion.

1 . An automatic injection device for providing an injection of a substance into a user, the automatic injection device comprising:
 a housing having a distal end operable by a user and an open proximal end for placement at an injection site;   a syringe movably disposed within the housing, the syringe having a needle and the substance contained therein;   a plunger having a continuous length from a first end to a second end opposite the first end, the first end extending into a barrel of the syringe and the second end initially seated on a retaining flange disposed within the distal end of the housing;   a radially shaped damper disposed within the housing to damp movement of the syringe;   a biasing mechanism disposed in the distal end of the housing and configured to apply pressure to the plunger when activated and move the plunger towards the proximal end of the housing; and   a firing mechanism assembly operable by the user to unseat the second end of the plunger from the syringe from the retaining flange.   
     
     
         2 . The automatic injection device of  claim 1 , wherein the plunger is configured to move the syringe towards the proximal end of the housing and cause the needle to protrude from the proximal end of the housing in a first stage of operation. 
     
     
         3 . The automatic injection device of  claim 2 , further comprising a stopping mechanism configured to stop further movement of the syringe towards the proximal end of the housing in a second stage of operation. 
     
     
         4 . The automatic injection device of  claim 1 , further comprising a flange disposed on the plunger between the first end and the second end of the plunger, wherein the flange is configured to hold the biasing mechanism in a compressed position until activation. 
     
     
         5 . The automatic injection device of  claim 4 , wherein the plunger includes a base extending from the flange towards the distal end of the housing. 
     
     
         6 . The automatic injection device of  claim 5 , wherein the base terminates in an anchoring portion for holding the biasing mechanism in a retracted position. 
     
     
         7 . The automatic injection device of  claim 1 , further comprising:
 a spring disposed in the proximal end of the housing and configured to hold the syringe in a retracted position.   
     
     
         8 . The automatic injection device of  claim 1 , wherein the plunger extends through the biasing mechanism. 
     
     
         9 . The automatic injection device of  claim 1 , further comprising:
 a syringe carrier disposed in the housing surrounding the syringe.   
     
     
         10 . The automatic injection device of  claim 9 , wherein the plunger is configured to move the syringe carrier. 
     
     
         11 . The automatic injection device of  claim 10 , wherein the stopping mechanism limits movement of the syringe carrier, and the syringe carrier limits movement of the syringe towards the proximal end of the housing. 
     
     
         12 . (canceled) 
     
     
         13 . The automatic injection device of  claim 9 , wherein the syringe carrier comprises a proximate anchor portion to limit movement of the syringe towards the distal end of the housing. 
     
     
         14 . The automatic injection device of  claim 9 , wherein the syringe carrier comprises cutouts that align with a window of the housing. 
     
     
         15 . The automatic injection device of  claim 1 , wherein the second end of the plunger is bifurcated and includes two arms. 
     
     
         16 . The automatic injection device of  claim 9 , wherein the radially shaped damper is disposed at a distal end of the syringe carrier to damp movement of the syringe. 
     
     
         17 . The automatic injection device of  claim 1 , wherein the plunger is a unitary plunger. 
     
     
         18 . The automatic injection device of  claim 1 , further comprising:
 a trigger to retain the biasing mechanism in a latched position; and   an activation button that when actuated causes the trigger to release the biasing mechanism.