Retractable sleeve for pen needle assembly

Abstract

A needle hub assembly for a pen needle includes a needle hub, a cannula or needle coupled to the needle hub, a retractable and compressible sleeve covering at least one end of the cannula, and an outer cover. The outer cover encloses the needle hub and the retractable sleeve. The retractable sleeve is coupled to the hub to cover the end of the cannula where the sleeve can pass through or can be pierced by the cannula and the sleeve retracts axially on the cannula. The sleeve is resilient and returns to an original configuration when an insertion force is released. The needle hub can have a first sleeve to cover a patient end of the cannula, and second sleeve to cover a non-patient end of the cannula where the sleeves retract onto the cannula or hub and expand to the original configuration to cover the ends of the cannula.

1 . A device for coupling to a pen needle, the device comprising:
 a needle hub having a side wall, an open proximal end for coupling with a delivery device for delivering a medication, a distal end opposite the open proximal end, and a cannula having a first end extending from the distal end for introducing the medication to a patient, and the cannula having a second end extending in a proximal direction and configured for piercing a septum of the delivery device;   a resilient first sleeve having an end wall and an open end, the open end of the resilient first sleeve coupled to the distal end of the needle hub and enclosing the first end of the cannula, wherein the cannula passes through the end wall of the resilient first sleeve and the resilient first sleeve retracts in a longitudinal direction with respect to the first end of the cannula when the first end of the cannula is inserted into the patient; and   a distal post extending from the distal end of the needle hub and having a side surface spaced inwardly from the side wall of the needle hub, wherein the resilient first sleeve is coupled to the side surface of the distal post, and wherein the resilient first sleeve is compressible and foldable onto the distal post where the end wall of the resilient first sleeve contacts and conforms to an axial face of the distal post.   
     
     
         2 . The device of  claim 1 , further comprising:
 a resilient second sleeve having an end wall and an open end, the open end of the resilient second sleeve coupled to the open proximal end of the needle hub and covering the second end of the cannula,   wherein the cannula passes through the end wall of the resilient second sleeve and the resilient second sleeve retracts in a longitudinal direction with respect to the second end of the cannula when the needle hub is threaded onto the delivery device.   
     
     
         3 . The device of  claim 2 , wherein the end wall of the resilient first sleeve has an opening with a dimension to allow the first end of the cannula to pass through, and
 wherein the end wall of the resilient second sleeve has an opening with a dimension to allow the second end of the cannula to pass through.   
     
     
         4 . The device of  claim 3 , wherein the resilient first sleeve retracts on the needle hub with respect to the first end of the cannula when the cannula is inserted into the patient, and
 wherein the resilient second sleeve retracts on the needle hub with respect to the second end of the cannula when the needle hub is coupled to the delivery device.   
     
     
         5 . The device of  claim 4 , wherein the resilient first sleeve is configured to expand to cover the first end of the cannula when the cannula is removed from the patient, and
 wherein the resilient second sleeve is configured to expand to cover the second end of the cannula when the needle hub is separated from the delivery device.   
     
     
         6 . The device of  claim 2 , wherein the resilient first sleeve is compressible and foldable in a longitudinal dimension and can be pierced by the first end of the cannula to expose the first end of the cannula when a cannula insertion force is applied against a skin of the patient, and
 wherein the resilient second sleeve is compressible and foldable in a longitudinal dimension and can be pierced by the second end of the cannula to expose the second end of the cannula when the needle hub is connected to the delivery device.   
     
     
         7 . The device of  claim 1 , wherein the end wall of the resilient first sleeve has a diameter and a thickness to conform to a skin surface of the patient when the end wall of the resilient first sleeve contacts the skin surface. 
     
     
         8 . The device of  claim 7 , wherein the resilient first sleeve has a side wall,
 wherein the thickness of the end wall of the resilient first sleeve is 1.5 to 2 times greater than a thickness of the side wall of the resilient first sleeve,   wherein the diameter of the end wall of the resilient first sleeve is greater than a diameter of the side wall of the resilient first sleeve,   wherein the end wall of the resilient first sleeve has the diameter and the thickness to form a skin contact surface for stabilizing the needle hub during insertion of the cannula into the patient, and   wherein the end wall of the resilient first sleeve is substantially flat and oriented in a plane substantially perpendicular to a longitudinal axis of the cannula.   
     
     
         9 . The device of  claim 2 , wherein the resilient first sleeve and the resilient second sleeve are compressible and foldable axially relative to the cannula when an axial force is applied to the resilient first sleeve and the resilient second sleeve, respectively, and expandable to an original position to cover the cannula when the axial force is released. 
     
     
         10 . The device of  claim 1 , wherein the axial face of the distal post has an outer ring at an outer edge of the axial face, and an inner ring at a center portion of the axial face,
 wherein the inner ring and the outer ring defining a skin shaping surface and defining a recess between the inner ring and the outer ring, and   wherein the outer ring, the inner ring, and the recess define a convex surface having a continuous radius of curvature.   
     
     
         11 . The device of  claim 1 , wherein the side wall of the needle hub further comprises internal threads. 
     
     
         12 . A device for coupling to a pen needle, the device comprising:
 a needle hub having a side wall, an open proximal end, and an end wall at a distal closed end of said side wall, the open proximal end configured for coupling to a delivery device;   a distal post extending from said end wall of said needle hub and having an outer axial face, the outer axial face of the distal post has an outer ring at an outer edge of the outer axial face, and an inner ring at a center portion of the outer axial face, the inner ring and the outer ring defining a skin shaping surface and defining a recess between the inner ring and the outer ring, wherein the outer ring, the inner ring, and the recess define a convex surface having a continuous radius of curvature;   a proximal post extending from an inner surface of the end wall of the needle hub, wherein the proximal post extends towards the open proximal end of the needle hub;   a cannula having a first end extending from a distal end of the distal post for introducing a medication to a patient, and a second end extending from the proximal post for piercing a septum on the delivery device and positioned in a cavity defined by the side wall; and   a resilient first sleeve having an end wall and an open end, the open end of the resilient first sleeve coupled to the distal post and enclosing the first end of the cannula, the resilient first sleeve being compressible and foldable onto the distal post when the cannula is inserted into a patient where the end wall of the resilient first sleeve conforms to the convex surface of the distal post.   
     
     
         13 . The device of  claim 12 , wherein the resilient first sleeve has a side wall with a proximal portion having a substantially cylindrical shaped side wall,
 wherein the proximal portion of the side wall has an open proximal end with an inner dimension complementing an outer dimension of the distal post,   wherein the end wall of the resilient first sleeve has a diameter greater than an outer diameter of a distal portion of the side wall of the resilient first sleeve,   wherein the end wall has an opening extending through the end wall of the resilient first sleeve with a dimension to allow the cannula to pass through, and   wherein the proximal portion has a width greater than the distal portion.   
     
     
         14 . The device of  claim 12 , further comprising a resilient second sleeve having an end wall and an open end, the open end of the resilient second sleeve coupled to the proximal post and enclosing the second end of the cannula, the resilient second sleeve being compressible and foldable onto the proximal post when the needle hub is connected to the delivery device. 
     
     
         15 . The device of  claim 14 , wherein the resilient second sleeve has a substantially cylindrical side wall, the side wall of the resilient second sleeve having an open proximal end with an inner dimension complementing an outer dimension of the proximal post,
 wherein the end wall of the resilient second sleeve has a diameter greater than an outer diameter of the side wall of the resilient second sleeve, and   wherein the end wall has an opening extending through the end wall of the resilient second sleeve with a dimension to allow the cannula to pass through.   
     
     
         16 . The device of  claim 12 , wherein the side wall of the resilient first sleeve has a conical shaped distal end proximate the end wall of the resilient first sleeve, and
 wherein the end wall of the resilient first sleeve has an axial face greater than an outer dimension of the conical shaped distal end of the side wall.   
     
     
         17 . The device of  claim 12 , wherein the outer axial face has an outer dimension less than an outer dimension of the side wall of the needle hub. 
     
     
         18 . The device of  claim 12 , wherein the outer axial face of the distal post has a radius of curvature of 6.0 mm to 9.0 mm. 
     
     
         19 . The device of  claim 12 , wherein the resilient first sleeve is coupled to a side wall of the distal post. 
     
     
         20 . The device of  claim 12 , wherein the end wall of the resilient first sleeve includes ribs to provide sufficient strength to the end wall to resist deflection and deforming of the end wall inwardly.