Autoinjectors Having Advanced Release and Sound Features

Abstract

Autoinjectors and methods of injection are described that feature release mechanisms and/or end-of-dose sound which can operate in conjunction with a powered plunger to efficiently inject a controlled dose from a syringe.

1 . A method of releasing a mechanism for an injector (initiating plunger action—which would dispense a load held within the barrel of a syringe), comprising:
 pressing an activation sleeve that is located at a proximal end of an injector; wherein the activation sleeve rotates a locking collar using a camming action; wherein the rotation of the locking collar rotates a nut thereby releasing the autoinjector mechanism. 
 
     
     
         2 . The method in  claim 1  wherein the locking collar is rotationally keyed to the nut sectors such that when the locking collar rotates, the nut sectors cause plunger screw pins to rotate off support ledges. 
     
     
         3 . The method of  claim 1  wherein the plunger screw pins are forced down a helical thread by the drive spring thereby inserting the needle and delivering medicant to a patient. 
     
     
         4 . The method of  claim 1  wherein the plunger screw is rotationally keyed to the end cap whereby the end cap is prevented from rotating by features attached to a housing. 
     
     
         5 . The method of  claim 4  wherein the end cap is attached with a cap lock that secures the end cap to the housing. 
     
     
         6 . The method of  claim 4  wherein the end cap is attached and retained to the housing by welding, bonding, snap fit, or interference fit. 
     
     
         7 . The method of  claim 1  wherein the activation sleeve is extended by a sleeve spring when the device is removed from a patient's skin surface after delivery of medication is complete. 
     
     
         8 . The method of  claim 1  wherein the locking collar rotates as the activation sleeve is fully extended thereby locking the activation sleeve in a fully extended position after use. 
     
     
         9 - 17 . (canceled) 
     
     
         18 . A method of producing an audible or tactile feedback in an injector, comprising:
 providing an injector comprising a drive spring adapted to provide force to move a plunger screw in the proximal direction;   the plunger screw comprising a pin adapted to ride in a thread formed by a nut;   wherein the thread of the nut comprises an interruption;   wherein, during operation of the injector, when the plunger screw pin encounters the interruption there is a sudden and rapid movement that causes the audible or tactile feedback.   
     
     
         19 . The method of  claim 18  wherein the interruption comprises a change in slope (second derivative) toward the distal direction followed by an abrupt change in slope in the proximal direction ultimately returning to approximately the same slope as prior to the interruption. Force was measured as described above. 
     
     
         20 . The method of  claim 18  wherein the plunger screw proceeds in the proximal direction at a first force and, in the vicinity of the interruption, force on the plunger screw increases by at least 2.5 N, or at least 5 N, or in the range of 2.5 to 10 N and then reduces to the first force or less over a distance in the proximal direction over a distance of 4 mm or less, 2 mm or less, or 1 mm or less (or in the range of 0.3 to 3 mm). 
     
     
         21 . The method of  claim 20  wherein the reduction in force is 2.5 N, or at least 5 N, or in the range of 2.5 to 10 N as compared to the first force. 
     
     
         22 . The method of  claim 21  wherein the force on the plunger screw is constant within 5 N for a distance of at least 10 mm, or at least 20 mm, or in the range of 10 to 200 mm, as the plunger screw proceeds in the proximal direction prior to the interruption. 
     
     
         23 . The method of  claim 18  wherein the plunger screw proceeds in the proximal direction at a first force and, in the vicinity of the interruption, force on the plunger screw increases by at least 10% or at least 20% or at least 25% or in the range of 10 to 50%) and then reduces to the first force or less over a distance in the proximal direction over a distance of 4 mm or less, 2 mm or less, or 1 mm or less (or in the range of 0.3 to 3 mm). 
     
     
         24 . The method of  claim 20  wherein the reduction in force is 2.5 N, or at least 5 N, or in the range of 2.5 to 10 N (alternatively, force on the plunger screw increases by at least 10% or at least 20% or in the range of 10 to 50%) as compared to the first force. 
     
     
         25 . The method of  claim 24  wherein the force on the plunger screw is constant within 5 N (or within 20% or within 10%) for a distance of at least 10 mm, or at least 20 mm, or in the range of 10 to 200 mm, as the plunger screw proceeds in the proximal direction prior to the interruption. 
     
     
         26 . The method of  claim 18  wherein the plunger screw proceeds in the proximal direction at a first force and, in the vicinity of the interruption, force on the plunger screw decreases by at least 10% or at least 20%, or at least 25%, or in the range of 10 to 50%, over a distance in the proximal direction over a distance of 4 mm or less, 2 mm or less, or 1 mm or less, or in the range of 0.3 to 3 mm. 
     
     
         27 . The method of  claim 26  wherein, in the vicinity of the interruption, the force on the plunger screw both increases and decreases over a distance of 4 mm or less, 2 mm or less, or 1 mm or less, or in the range of 0.5 to 4 mm or 0.5 to 3 mm. 
     
     
         28 . An autoinjector configured to product an audible or tactile feedback to a user, comprising:
 an injector comprising a drive spring adapted to provide force to move a plunger screw in the proximal direction;   the plunger screw comprising a pin adapted to ride in a thread formed by a nut;   wherein the thread of the nut comprises an interruption;   configured such that, during operation of the injector, when the plunger screw pin encounters the interruption there is a sudden and rapid movement that causes the audible or tactile feedback.