Connection of a stopper and piston in a fluid delivery device

Abstract

A device for delivering fluid to a user includes a fluid reservoir for holding the fluid, the fluid reservoir defining an internal volume and a stopper positioned in the internal volume of the fluid reservoir, wherein the stopper is formed with a cavity. The device further includes a piston having a distal end received within the cavity of the stopper and an actuator coupled to the piston for driving the piston into the internal volume of the fluid reservoir. Also, the device includes a coupling device for engaging the piston in the cavity of the stopper at a desired position and a sensor for determining whether the piston is engaged in the cavity of the stopper at the desired position.

1 - 20 . (canceled) 
     
     
         21 : A device for delivering fluid to a user, the device comprising:
 a fluid reservoir for holding the fluid, the fluid reservoir defining an internal volume and a stopper positioned in the internal volume of the fluid reservoir, wherein the stopper is formed with a cavity;   a piston having a distal end received within the cavity of the stopper;   an actuator coupled to the piston for driving the piston into the internal volume of the fluid reservoir; and   a coupling device coupled to the stopper and the piston and configured to prevent axial separation of the stopper from the piston.   
     
     
         22 : The device of  claim 21 , wherein the coupling device is a magnetic coupling device, the magnetic coupling device including a first component mounted to the stopper and a second component mounted to the piston, wherein the first component and the second component are configured to engage the piston in the cavity of the stopper at a desired position to prevent the axial separation of the stopper from the piston. 
     
     
         23 : The device of  claim 22 , further comprising a sensor coupled to at least one of the first component or the second component, wherein the sensor is configured to detect magnetic field strength of at least one of the first component or the second component to generate information indicative of whether there is the axial separation of the fluid delivery device stopper from the piston. 
     
     
         24 : The device of  claim 21 , wherein the stopper has an inner sidewall surface, wherein the piston has an outer surface, and wherein the coupling device comprises a recess formed in the inner sidewall surface and a flexible wing extending outward from the outer surface of the piston, the flexible wing being configured to extend into the recess and engage with the inner sidewall surface of the stopper. 
     
     
         25 : The device of  claim 24 , further comprising a sensor coupled to the flexible wing, wherein the sensor is configured to detect deflection pressure on the flexible wing to generate information indicative of whether there is the axial separation of the fluid delivery device stopper from the piston. 
     
     
         26 : The device of  claim 21 , wherein the stopper has an inner sidewall surface, and wherein the coupling device comprises a recess formed in the inner sidewall surface and a spring-loaded ball element mounted to the piston, the spring-loaded ball element being configured to extend into the recess and engage with the inner sidewall surface of the stopper. 
     
     
         27 : The device of  claim 26 , further comprising a sensor coupled to the spring-loaded ball element, wherein the sensor is configured to detect spring tension on the spring-loaded ball element to generate information indicative of whether there is the axial separation of the fluid delivery device stopper from the piston. 
     
     
         28 : The device of  claim 21 , wherein the coupling device is configured to prevent the stopper from slipping or reducing, in an uncontrolled manner, a volume of the fluid in the fluid reservoir by preventing the axial separation of the stopper from the piston. 
     
     
         29 : A device for detecting whether a fluid delivery device stopper is correctly positioned, the device comprising:
 a fluid reservoir for holding fluid, the fluid reservoir defining an internal volume, wherein the fluid delivery device stopper is formed with a cavity;   a piston having a distal end received within the cavity of the fluid delivery device stopper; and   a sensor configured to generate information indicative of whether there is axial separation of the fluid delivery device stopper from the piston.   
     
     
         30 : The device of  claim 29 , wherein the sensor is configured to generate information indicative of whether there is axial separation of the fluid delivery device stopper from the piston based on detection of a magnetic field strength between the fluid delivery device stopper and the piston. 
     
     
         31 : The device of  claim 29 , wherein the piston has an outer surface and a flexible wing extending outward from the outer surface of the piston and configured to contact the fluid delivery device stopper, and wherein the sensor is configured to detect deflection pressure on the flexible wing to generate information indicative of whether there is the axial separation of the fluid delivery device stopper from the piston. 
     
     
         32 : The device of  claim 29 , wherein a spring-loaded ball element is mounted to the piston, and wherein the sensor is configured to detect spring tension on the spring-loaded ball element to generate information indicative of whether there is the axial separation of the fluid delivery device stopper from the piston. 
     
     
         33 : The device of  claim 29 , wherein the sensor comprises:
 a projection mounted to the fluid delivery device stopper and extending into the cavity of the fluid delivery device stopper; and   a pressure sensor mounted to the piston, wherein the projection contacts the pressure sensor when the piston is engaged in the cavity of the fluid delivery device stopper.   
     
     
         34 : The device of  claim 33 , wherein the pressure sensor comprises an electric field proximity sensor.