Tympanostomy tube delivery device with elastomeric brake

Abstract

An instrument comprises a handpiece, a boss member, a cylindraceous cam body, a linearly movable member, a cam follower, and a braking member. The cam body is rotatably supported in the handpiece and includes an exterior cam feature. The cam follower couples the linearly movable member with the cam feature of the cam body. The cam feature and the cam follower cooperatively drive the linearly movable member linearly in response to rotation of the cam body within the handpiece. The braking member extends about at least a portion of the exterior of the cam body and is positioned to progressively engage the boss member as the cam body rotates within the handpiece. The braking member and the boss member thus cooperate to provide gradual braking of the cam body. The instrument is operable to deploy a pressure equalization tube in the tympanic membrane of a patient.

I/we claim: 
     
         1 . An instrument, comprising:
 (a) a handpiece body;   (b) a boss member fixed relative to the handpiece body;   (c) a cylindraceous cam body rotatably supported in the handpiece body, wherein the exterior of the cam body includes a cam feature;   (d) a linearly movable member;   (e) a cam follower coupling the linearly movable member with the cam feature of the cam body, wherein the cam feature and the cam follower are configured to cooperatively drive the linearly movable member linearly in response to rotation of the cam body within the handpiece body; and   (f) a braking member extending about at least a portion of the exterior of the cam body, wherein the braking member is positioned to progressively engage the boss member as the cam body rotates within the handpiece body.   
     
     
         2 . The instrument of  claim 1 , wherein the braking member comprises an elastomeric material. 
     
     
         3 . The instrument of  claim 2 , wherein the braking member comprises an o-ring. 
     
     
         4 . The instrument of  claim 1 , wherein the cam body defines a recess, wherein at least a portion of the braking member is disposed in the recess. 
     
     
         5 . The instrument of  claim 1 , wherein the recess comprises a first curved surface and a second curved surface, wherein the first curved surface has a first curvature defined by a first radius, wherein the second curved surface has a second curvature defined by a second radius. 
     
     
         6 . The instrument of  claim 5 , wherein the cam body defines a longitudinal axis, wherein the first curvature is defined by the first radius extending from an origin positioned on the longitudinal axis of the cam body. 
     
     
         7 . The instrument of  claim 6 , wherein the second curvature is defined by the second radius extending from the origin positioned on the longitudinal axis of the cam body. 
     
     
         8 . The instrument of  claim 5 , wherein the recess further comprises a first flat surface extending from the first curved surface to the second curved surface. 
     
     
         9 . The instrument of  claim 8 , wherein the recess further comprises a second flat surface extending from the first curved surface to the second curved surface. 
     
     
         10 . The instrument of  claim 5 , wherein the first curved surface and the second curved surface extend along a common plane. 
     
     
         11 . The instrument of  claim 10 , wherein the cam body defines a longitudinal axis, wherein the common plane is perpendicular to the longitudinal axis. 
     
     
         12 . The instrument of  claim 1 , wherein the handpiece body comprises a housing, wherein the boss member is unitarily formed in the housing. 
     
     
         13 . The instrument of  claim 1 , wherein the boss member is rigid. 
     
     
         14 . The instrument of  claim 1 , wherein the boss member is configured to bear radially inwardly on the braking member. 
     
     
         15 . The instrument of  claim 1 , wherein the boss member comprises an elastomeric material. 
     
     
         16 . The instrument of  claim 1 , wherein the braking member and the boss member are configured to cooperatively halt rotation of the cam body. 
     
     
         17 . The instrument of  claim 1 , further comprising a torsion spring, wherein the torsion spring is configured to resiliently bias the cam body to rotate within the handpiece body. 
     
     
         18 . The instrument of  claim 1 , further comprising a shaft assembly, wherein the linearly movable member forms part of the shaft assembly, wherein the shaft assembly is operable to deploy a pressure equalization tube in a tympanic membrane in response to rotation of the cam body within the handpiece body. 
     
     
         19 . An instrument, comprising:
 (a) a handpiece body;   (b) a boss member fixed relative to the handpiece body;   (c) a cylindraceous cam body rotatably supported in the handpiece body;   (d) a shaft assembly extending distally from the handpiece body, wherein the shaft assembly is operable to deploy a pressure equalization tube in a tympanic membrane in response to rotation of the cam body within the handpiece body; and   (e) a braking member extending about at least a portion of the exterior of the cam body, wherein the boss member is configured to progressively bear against the braking member as the cam body rotates within the handpiece body to thereby gradually arrest rotation of the cam body within the handpiece body.   
     
     
         20 . An instrument, comprising:
 (a) a handpiece body;   (b) a boss member fixed relative to the handpiece body;   (c) a cylindraceous cam body rotatably supported in the handpiece body, wherein the cam body defines a longitudinal axis;   (d) a shaft assembly extending distally from the handpiece body, wherein the shaft assembly is operable to pierce a tympanic membrane in response to rotation of the cam body within the handpiece body; and   (e) an elastomeric member extending about at least a portion of the exterior of the cam body, wherein the elastomeric member extends along a first portion of the cam body and along a second portion of the cam body, wherein the first portion of the cam body is located at a first distance from the longitudinal axis, wherein the second portion of the cam body is located at a second distance from the longitudinal axis, wherein the boss member is configured to progressively engage the elastomeric member as the cam body rotates within the handpiece body to thereby gradually arrest rotation of the cam body within the handpiece body.