Automatic injector

Abstract

An injector is automatic in that the needle is inserted into the injection site (e.g., a patient's skin) with user or caregiver assistance, the delivery is automatically initiated upon needle insertion, and the needle is retracted automatically after the end of delivery. Preferably the needle is not seen by the user prior to, during or after injection. Prior to and after injection, the needle is hidden in the device so as to avoid any potential injury or health risk to the user or health care provider. The injector includes a housing and a shield arranged to slide relative to the housing and a driver moving during drug delivery. The housing and shield form a cartridge enclosure. The cartridge is shielded and locked after delivery is completed. A needle-locking mechanism can be used in any number of pen-like injectors or safety needles.

1 . An injector for automatically injecting and delivering fluids into a living being, said injector comprising: 
 a housing having a first proximal end and a first distal end that is open;    a cartridge having a barrel containing a fluid, said cartridge further comprising a displaceable stopper at a second proximal end and a needle at a second distal end, said cartridge being fixed within said housing;    a driver engaged within said housing for driving said stopper to dispense the fluid from said barrel and through said needle when disengaged from said housing;    a needle shield being in sliding engagement with said first distal end of said housing and comprising an opening for permitting said needle to pass therethrough; and    a single spring, engaged with said driver, that is released by a user force, said single spring displacing said driver for automatically injecting and delivering the fluid into the living being and for automatically acting against the needle shield to remove the needle from the living being while concealing the needle once the fluid delivery is complete.    
   
   
       2 . The injector of  claim 1  wherein said second distal end of the barrel comprises a reduced-diameter portion and wherein said driver comprises members that ride along the barrel when said driver is disengaged from said housing, said single spring acting against said needle shield whenever said members contact said reduced-diameter portion.  
   
   
       3 . The injector of  claim 1  wherein said driver comprises latches for engaging said housing and wherein said single spring acts against said latches to move said driver when said latches are disengaged from said housing.  
   
   
       4 . The injector of  claim 3  wherein said needle shield is positioned against the living being and application of said user force causes said needle shield to disengage said latches from said housing.  
   
   
       5 . The injector of  claim 2  further comprising a locking mechanism that prevents the needle shield from being displaced toward said housing after said single spring has acted against said needle shield.  
   
   
       6 . The injector of  claim 1  wherein said user force is approximately 10 Newtons.  
   
   
       7 . The injector of  claim 5  wherein said needle shield slides on said housing.  
   
   
       8 . The injector of  claim 5  wherein said needle shield slides inside said housing.  
   
   
       9 . The injector of  claim 4  wherein said driver comprises a driver rod that engages said stopper.  
   
   
       10 . The injector of  claim 2  wherein said single spring acting against said needle shield provides the user with a tactile and audible feedback of the end of the fluid delivery.  
   
   
       11 . The injector of  claim 7  wherein said locking mechanism comprises leaf springs in said housing that are forced inward of said housing when said single spring acts against said needle shield, said needle shield further comprising latches on an inside surface of said needle shield, said latches on said inside surface of said needle shield engaging said leaf springs, thereby preventing said needle shield from being displaced toward said housing.  
   
   
       12 . The injector of  claim 8  wherein said locking mechanism comprises latch members in an inner surface of said housing and said needle shield comprises corresponding latch members located on an outside surface of said shield, said corresponding latch member located on said outside surface engaging said latch members on said inner surface of said housing, thereby preventing said needle shield from being displaced toward said housing.  
   
   
       13 . The injector of  claim 7  wherein said locking mechanism comprises pins and pin-slots that are used on said housing and needle shield respectively to prevent said needle shield from being displaced toward said housing after said single spring has acted against said needle shield.  
   
   
       14 . The injector of  claim 8  wherein said locking mechanism comprises pins and pin-slots that are used on said housing and needle shield respectively to prevent said needle shield from being displaced toward said housing after said single spring has acted against said needle shield.  
   
   
       15 . The injector of  claim 9  wherein said housing further comprises an observation window to permit the user to see the contents of the barrel.  
   
   
       16 . The injector of  claim 15  further comprising a titrating rod that passes through an opening in said first proximal end, said titrating rod passing through a passageway in said driver rod and contacting said stopper for dispensing the fluid during titration, said titrating rod not being coupled to said stopper.  
   
   
       17 . The injector of  claim 16  wherein said titrating rod comprises a smooth shaft portion for axial movement with respect to a housing axis.  
   
   
       18 . The injector of  claim 16  wherein said titrating rod comprises a threaded shaft portion for rotational axial movement with respect to a housing axis.  
   
   
       19 . The injector of  claim 16  wherein said titrating rod comprises a ratcheted shaft portion for incremental axial movement with respect to a housing axis.  
   
   
       20 . The injector of  claim 1  further comprising a safety ring releasably secured between said housing and said needle shield, said ring arranged to prevent activation of said injector when said ring is engaged between said housing and said needle shield.  
   
   
       21 . An injector for automatically injecting and delivering fluids into a living being, said injector comprising: 
 a housing having a first proximal end and a first distal end that is open;    a cartridge having a barrel containing a fluid, said cartridge further comprising a displaceable stopper at a second proximal end and a needle at a second distal end having a reduced-diameter portion, said cartridge being fixed within said housing;    a driver engaged within said housing for driving said stopper to dispense the fluid from said barrel and through said needle when disengaged from said housing, said driver comprising members that slide along said barrel and detect said reduced-diameter portion;    a needle shield being in sliding engagement with said first distal end of said housing and comprising an opening for permitting said needle to pass therethrough; and    driving means, engaged with said driver, that is released by a user force, said driving means displacing said driver for automatically injecting and delivering the fluid into the living being, said driving means also automatically acting against said needle shield to remove the needle from the living being while concealing said needle when said reduced-diameter portion is detected.    
   
   
       22 . The injector of  claim 22  wherein said driving means is a single spring.  
   
   
       23 . The injector of  claim 22  wherein said driver comprises latches for engaging said housing and wherein said single spring acts against said latches to move said driver when said latches are disengaged from said housing.  
   
   
       24 . The injector of  claim 23  wherein said needle shield is positioned against the living being and application of said user force causes said needle shield to disengage said latches from said housing.  
   
   
       25 . The injector of  claim 22  further comprising a locking mechanism that prevents the needle shield from being displaced toward said housing after said single spring has acted against said needle shield.  
   
   
       26 . The injector of  claim 21  wherein said user force is approximately 10 Newtons.  
   
   
       27 . The injector of  claim 25  wherein said needle shield slides on said housing.  
   
   
       28 . The injector of  claim 25  wherein said needle shield slides inside said housing.  
   
   
       29 . The injector of  claim 24  wherein said driver comprises a driver rod that engages said stopper.  
   
   
       30 . The injector of  claim 22  wherein said single spring acting against said needle shield provides the user with a tactile and audible feedback of the end of the fluid delivery.  
   
   
       31 . The injector of  claim 27  wherein said locking mechanism comprises leaf springs in said housing that are forced inward of said housing when said single spring acts against said needle shield, said needle shield further comprising latches on an inside surface of said needle shield, said latches on said inside surface of said needle shield engaging said leaf springs, thereby preventing said needle shield from being displaced toward said housing.  
   
   
       32 . The injector of  claim 28  wherein said locking mechanism comprises latch members in an inner surface of said housing and said needle shield comprises corresponding latch members located on an outside surface of said shield, said corresponding latch member located on said outside surface engaging said latch members on said inner surface of said housing, thereby preventing said needle shield from being displaced toward said housing.  
   
   
       33 . The injector of  claim 27  wherein said locking mechanism comprises pins and pin-slots that are used on said housing and needle shield respectively to prevent said needle shield from being displaced toward said housing after said single spring has acted against said needle shield.  
   
   
       34 . The injector of  claim 28  wherein said locking mechanism comprises pins and pin-slots that are used on said housing and needle shield respectively to prevent said needle shield from being displaced toward said housing after said single spring has acted against said needle shield.  
   
   
       35 . The injector of  claim 29  wherein said housing further comprises an observation window to permit the user to see the contents of the barrel.  
   
   
       36 . The injector of  claim 35  further comprising a titrating rod that passes through an opening in said first proximal end, said titrating rod passing through a passageway in said driver rod and contacting said stopper for dispensing the fluid during titration, said titrating rod not being coupled to said stopper.  
   
   
       37 . The injector of  claim 36  wherein said titrating rod comprises a smooth shaft portion for axial movement with respect to a housing axis.  
   
   
       38 . The injector of  claim 36  wherein said titrating rod comprises a threaded shaft portion for rotational axial movement with respect to a housing axis.  
   
   
       39 . The injector of  claim 36  wherein said titrating rod comprises a ratcheted shaft portion for incremental axial movement with respect to a housing axis.  
   
   
       40 . The injector of  claim 21  further comprising a safety ring releasably secured between said housing and said needle shield, said ring arranged to prevent activation of said injector when said ring is engaged between said housing and said needle shield.  
   
   
       41 . A method for automatically injecting and delivering a fluid into a living being, said method comprising the steps of: 
 disposing a cartridge inside an injector housing having a first proximal end and a first distal end, said cartridge having a barrel having a second proximal end and a second distal end, said second proximal end having a movable stopper thereat and said second distal end having a reduced-diameter portion having a needle thereat;    providing a needle shield to be in sliding engagement with said injector housing at said first distal end, said needle shield comprising an opening to permit said needle to pass therethrough;    latching a driver inside said injector housing against the bias of a single spring, said driver having a driver rod engaged with said stopper;    positioning said needle shield and opening against the living being;    applying a sufficient force to said injector housing to de-latch said driver while driving said needle shield towards said housing and inserting said needle into the living being;    displacing said stopper by said driver under the action of said single spring to dispense the fluid into the living being; and    detecting said reduced-diameter portion and permitting said single spring to act directly against said needle shield to withdraw said needle from the living being while concealing said needle.    
   
   
       42 . The method of  claim 41  further comprising the step of latching the needle shield to said injector housing thereby preventing said needle shield from being displaced and re-exposing said needle after the needle has been withdrawn from the living being.  
   
   
       43 . The method of  claim 41  wherein said step of detecting said reduced-diameter portion comprises members that ride along said barrel during driver displacement.  
   
   
       44 . The method of  claim 41  wherein said sufficient force comprises approximately 10 Newtons.  
   
   
       45 . The method of  claim 43  wherein said step of displacing said stopper by said driver comprises said single spring acting against a portion of said driver adjacent said members that ride along said barrel.