Devices Including an Annular Undercut

Abstract

A device including an annular undercut having a curved cross-sectional shape made by electrical discharge machining (EDM) is disclosed. An exemplary device with an EDM-formed annular undercut is a tool used for injection-molding of plastic parts having a crab's claw seal.

1 . A device including an annular undercut formed by electrical discharge machining (EDM), the device comprising:
 a body having a surface and an axis; and   EDM-formed annular inner and outer curved walls integral with the body concentric to the axis, the walls extending into the body from the surface to define the annular undercut therebetween, the annular undercut having a curved cross-sectional shape in a section lying in a plane including the axis.   
   
   
       2 . The device of  claim 1  wherein the body is generally cylindrically-shaped. 
   
   
       3 . The device of  claim 2  wherein the axis is a central axis and the plane bisects the body. 
   
   
       4 . The device of  claim 1  wherein the body further includes an end and the EDM-formed annular inner and outer curved walls extend into the body from the end. 
   
   
       5 . The device of  claim 1  wherein the device is a tool for molded part manufacture. 
   
   
       6 . The device of  claim 5  wherein the tool is a core. 
   
   
       7 . The device of  claim 5  wherein the body further includes a coolant passageway proximate the annular undercut. 
   
   
       8 . The device of  claim 5  wherein the annular undercut is sized to receive plastic material for manufacture of a crab's-claw-type seal in a plastic injection-molded part. 
   
   
       9 . The device of  claim 8  wherein the tool is sized for manufacture of a plastic injection-molded closure-type part including the crab's-claw-type seal. 
   
   
       10 . A device having an annular undercut formed therein by electrical discharge machining (EDM), the device comprising:
 a body; and   EDM-formed annular inner and outer walls extending into the body and defining the annular undercut therebetween, the walls further defining the undercut such that the undercut has a curved cross-sectional shape in a section lying in a plane including the walls.   
   
   
       11 . The device of  claim 10  wherein the EDM-formed annular inner and outer walls are curved. 
   
   
       12 . The device of  claim 10  wherein the body has an axis and the EDM-formed annular inner and outer walls are concentric to the axis. 
   
   
       13 . The device of  claim 12  wherein the axis lies in the plane and the plane bisects the body. 
   
   
       14 . The device of  claim 10  wherein the body is generally cylindrically-shaped. 
   
   
       15 . The device of  claim 14  wherein the body further includes an end and the EDM-formed annular inner and outer curved walls defining the annular undercut extend into the body from the end. 
   
   
       16 . The device of  claim 10  wherein the device is a tool for use in molded part manufacture. 
   
   
       17 . The device of  claim 16  wherein the tool is a core. 
   
   
       18 . The device of  claim 16  wherein the body further includes a coolant passageway proximate the annular undercut. 
   
   
       19 . The device of  claim 18  wherein the annular undercut is sized to receive plastic material for manufacture of a crab's-claw-type seal in a plastic injection-molded part. 
   
   
       20 . A device comprising concentric inner and outer walls formed by electrical discharge machining (EDM), the walls extending into the device from a device surface and defining an EDM-formed annular undercut therebetween, the walls further defining the undercut such that the undercut has a curved cross-sectional shape in a section lying in a plane including the walls.