Pen needle hub having increased contact area

Abstract

A pen needle assembly having a hub with an increased surface area that contacts a patient's skin is provided. The increased contact area of the hub with the patient's skin during injection of a cannula decreases the pressure exerted against the patient's skin, thereby increasing the comfort of the patient. A bonding adhesive is disposed on an outer surface of the hub, thereby decreasing the required curing time of the adhesive. Additionally, the increased contact area, between the cannula adhesive and hub increases the strength of the bond therebetween.

1 . A hub assembly for an injection apparatus, comprising:
 a body having a first end and an open second end;   a projection extending axially outwardly from said first end of said body, said projection having a distal end having an outer portion and an inner portion with an axially facing surface;   an opening in said distal end of said projection adapted to receive a cannula, said opening extending to an interior of said body;   said inner portion of said distal end having an inner sloping inwardly toward said opening, thereby facilitating movement of an adhesive to said opening to secure the cannula; and   said outer portion of said projection having an axially facing surface with a surface area greater than a surface area said inner portion and configured to disperse a pressure exerted against a patient's skin during an injection.   
     
     
         2 . The hub assembly for an injection apparatus according to  claim 1 , wherein said inner portion includes a plurality of radially extending ribs having an inner surface for bonding to the cannula. 
     
     
         3 . The hub assembly for an injection apparatus according to  claim 1 , wherein said opening includes a plurality of rings to facilitate receipt of the adhesive in said opening. 
     
     
         4 . The hub assembly for an injection apparatus according to  claim 1 , wherein said body further comprises an inner protrusion surrounded by said projection and having said opening extending through said inner protrusion, and said outer portion of said projection is formed by a plurality of circumferentially disposed members spaced radially from said inner protrusion. 
     
     
         5 . The hub assembly for an injection apparatus according to  claim 4 , wherein said plurality of members extend axially beyond said inner protrusion. 
     
     
         6 . The hub assembly for an injection apparatus according to  claim 4 , wherein ends of said plurality of members are substantially planar to facilitate injections substantially perpendicular to a skin surface. 
     
     
         7 . The hub assembly for an injection apparatus according to  claim 4 , wherein ends of said plurality of members are rounded to facilitate injections not perpendicular to a skin surface. 
     
     
         8 . The hub assembly for an injection apparatus according to  claim 1 , wherein a recessed annular ring is formed in said inner portion of said distal end of said projection. 
     
     
         9 . The hub assembly for an injection apparatus according to  claim 1 , wherein said body has an axially extending inner protrusion having an axial face, said projection surrounding said inner protrusion and spaced radially to form an annular recess between said inner protrusion and said projection, said projection having an axially facing surface with a substantially convex, curved outer surface extending between an outer peripheral surface of said projection and a distal end of said projection, where said curved outer surface is configured to contact and deform a skin surface of a patient during an injection to control deformation of the skin surface by said inner protrusion and limit a depth of penetration by said cannula. 
     
     
         10 . A hub assembly for an injection apparatus, comprising:
 a body having a first end and a second open end;   an inner protrusion extending outwardly from said first end of said body and having a distal end;   an opening in said distal end of said inner protrusion adapted to receive a cannula, said opening extending to an interior of said body; and   an outer projection spaced from and circumferentially surrounding said protrusion, a distal end of said outer projection having a radial width and a surface area greater than a radial width and surface area of said distal end of said inner protrusion, thereby reducing a pressure exerted against a patient's skin during an injection.   
     
     
         11 . The hub assembly for an injection apparatus according to  claim 10 , wherein said outer projection is formed by a plurality of circumferentially disposed members surrounding said inner protrusion. 
     
     
         12 . The hub assembly for an injection apparatus according to  claim 11 , wherein said plurality of members extend axially beyond said inner protrusion. 
     
     
         13 . The hub assembly for an injection apparatus according to  claim 10 , wherein said outer projection is spaced radially from said inner protrusion to form an annular recess, and where said outer projection has an axially facing surface with a substantially convex, curved outer surface extending between an outer peripheral edge of said outer projection and a distal end of said projection, said curved outer surface configured for contacting and deforming a skin surface of a patient during an injection by the cannula to control deformation of the skin surface and limit a depth of penetration by said inner protrusion and limit a depth of penetration of said cannula. 
     
     
         14 . The hub assembly for an injection apparatus according to  claim 10 , wherein a plurality of ribs extend axially along an outer surface of said inner protrusion. 
     
     
         15 . The hub assembly for an injection apparatus according to  claim 10 , wherein a recessed ring is formed between said outer projection and inner protrusion. 
     
     
         16 . The hub assembly for an injection apparatus according to  claim 11 , wherein said plurality of circumferentially disposed members having a planar axial face. 
     
     
         17 . The hub assembly for an injection apparatus according to  claim 11 , wherein said plurality of circumferentially disposed members have a rounded axial face. 
     
     
         18 . The hub assembly for an injection apparatus according to  claim 13 , wherein said inner protrusion has an annular shaped axial face spaced axially from said inner protrusion and said curved outer surface of said outer projection is oriented for contacting the skin surface during an injection. 
     
     
         19 . The hub assembly for an injection apparatus according to  claim 13 , wherein said inner protrusion has an axial face is substantially flush with said distal end of said outer projection. 
     
     
         20 . The hub assembly for an injection apparatus according to  claim 10 , wherein said outer projection has a continuous substantially hemispherical shaped defined by said curved outer surface of said outer projection.