Pen needle attachment mechanisms

Abstract

User-friendly attachment mechanisms for pen needles provide improved handling and ease of use, including locking installation and removal features and sensory feedback when a needle-bearing hub is seated on a pen. Embodiments include a needle-bearing hub having a circumferentially oriented flexible tab that engages a radially inward rib on an outer cover to assist in attaching a pen device to the pen needle.

What is claimed is: 
     
         1 . A pen needle, comprising
 a needle-bearing hub having threads for attachment to a medication delivery device and at least one circumferentially oriented flexible tab located proximally of the threads; and   an outer cover received over the hub covering the needle and having at least one radially inward projecting rib engaging the at least one flexible tab on the hub to provide sensory feedback for the user when the hub is installed on the medication delivery device;   wherein the at least one radially inward projecting rib comprises a plurality of radially inward projecting ribs for sequentially deflecting the at least one circumferentially oriented flexible tab to produce the sensory feedback as two or more sequential clicks when the hub offers sufficient resistance to applied rotational force to allow the outer cover to rotate with respect to the hub.   
     
     
         2 . The pen needle according to  claim 1 , wherein engagement of the hub with the outer cover prevents the outer cover from moving distally with respect to the hub until after the outer cover rotates with respect to the hub. 
     
     
         3 . A pen needle, comprising
 a needle-bearing hub having threads for attachment to a medication delivery device;   at least one circumferentially oriented flexible tab on the hub located proximally of the threads, the end of each flexible tab having a radially outward projection;   at least one hard stop on the hub located proximally of the threads projecting in a radially outward direction and a circumferential gap separating the radially outward projection on the flexible tab from the hard stop; and   an outer cover received over the hub covering the needle having at least one radially inward projecting rib; wherein   engagement of the at least one radially inward projecting rib on the outer cover with the projection on the flexible tab causes the hub to rotate with the outer cover when the hub offers low resistance to applied rotational force;   the projection on the flexible tab rides over the at least one radially inward projecting rib on the outer cover when the hub offers higher resistance to applied rotational force when the outer cover rotates with respect to the hub creating sensory feedback that the hub is fully installed on the medication delivery device;   engagement of the at least one radially inward projecting rib against the hard stop prevents rotation of the outer cover with respect to the hub when the hub is fully seated on the medication delivery device; and   the at least one radially inward projecting rib comprises a set of two or more radially inward projecting ribs on an inside surface of the outer cover engaging the projection on the flexible tab, each said set of two or more inward radially projecting ribs received in the circumferential gap between the hard stop and the radially outward projection on the end of the flexible tab, whereby the sensory feedback comprises two or more sequential clicks produced by the sequential engagement of the two or more radially inward projecting ribs with the projection on the flexible tab, followed by a stop.   
     
     
         4 . The pen needle according to  claim 3 , wherein
 the flexible tab has a plurality of radially outward projections which engage an inward projecting rib on the cover to create the sensory feedback.   
     
     
         5 . The pen needle according to  claim 3 , comprising two circumferentially oriented flexible tabs on the hub located proximally of the threads, each of said two circumferentially oriented flexible tabs having a radially outward projection on a respective end thereof, and two sets of two or more inwardly projecting ribs on the inside circumferential surface of the outer cover. 
     
     
         6 . The pen needle according to  claim 3 , comprising
 a circumferentially oriented ramp on the flexible tab having an increased diameter in the direction of the end of the flexible tab, which increases the force required to turn the outer cover with respect to the hub as the at least one radially inward projecting rib on the outer cover rides on the ramp.   
     
     
         7 . The pen needle according to  claim 3 , comprising
 a beveled surface on the projection on the flexible tab engaging a beveled surface on the at least one radially inward projecting rib.   
     
     
         8 . A pen needle, comprising
 a needle-bearing hub having threads for attachment to a medication delivery device and at least one circumferentially oriented flexible tab located proximally of the threads;   the at least one circumferentially oriented flexible tab having a radially outward surface with a projection, the projection having a beveled side; and   an outer cover having at least one radially inward projecting rib, the at least one radially inward projecting rib having a beveled surface engaging the beveled surface of the projection on the at least one circumferentially oriented flexible tab; wherein   engagement of the at least one radially inward projecting rib on the outer cover with the projection on the at least one circumferentially oriented flexible tab causes the hub to rotate with the outer cover when the hub offers low resistance to applied rotational force;   the projection on the at least one circumferentially oriented flexible tab deflects and rides over the at least one radially inward projecting rib on the outer cover when the outer cover rotates with respect to the hub at increased resistance to applied rotational force, creating an audible and/or tactile indication that the hub is fully installed on the medication delivery device; and   the at least one radially inward projecting rib comprises a set of two or more radially inward projecting ribs on an inside surface of the outer cover for sequentially engaging the projection on the at least one circumferentially oriented flexible tab to produce two or more sequential clicks.   
     
     
         9 . The pen needle according to  claim 8 , wherein the at least one circumferentially oriented flexible tab on the hub comprises two flexible tabs, each having a radially outward projection, said outward projections located about 180 degrees apart, radially opposite each other on the proximal end of the hub. 
     
     
         10 . The pen needle according to  claim 9 , wherein each said radially outward projection on the hub and each said radially inward projecting rib on the outer cover has a straight side perpendicular to a circumferential direction, and wherein the straight side on a radially outward projection on the hub and the straight side on a radially inward projecting rib on the outer cover engage each other when the outer cover and hub are rotated to remove the hub from the medication delivery device. 
     
     
         11 . A pen needle, comprising:
 a needle bearing hub having a patient side and a non-patient side, a post on the patient side of the hub and a patient end cannula extending from the post, and a cavity on the non-patient side having threads on an interior surface and a non-patient end cannula extending within the cavity,   a non-patient side shield having a cylindrical body covering the non-patient end needle and a lateral extension on the non-patient end of the cylindrical body having threads that mate with the threads on the inside surface of the cavity,   a patient side shield having a contour on an interior surface mating with a second contour on an outward surface of the post together providing a tortuous path sterile barrier around the patient side needle.   
     
     
         12 . The pen needle according to  claim 11 , further comprising:
 lateral extensions on the proximal end of the non-patient end shield to facilitate gripping.   
     
     
         13 . The pen needle according to  claim 11 , further comprising indicia on the cylindrical body of the non-patient end shield. 
     
     
         14 . The pen needle according to  claim 11 , wherein the non-patient end shield and the patient end shield each has a diameter one-third to one-tenth the diameter of the hub to form a spindle configuration.