Pop-up sink drain with overflow knock-out blank

Abstract

A drain body used to connect a sink drain to drainage pipes for use with sinks having integral overflow protection and sinks with conventional overflow ports. The drain body comprises a hollow cylinder with an upper flange including an upper sidewall portion defining a knock out blank which may be left in place or may be easily removed, thus providing a hole through which the overflow water which is carried through an integral tunnel in the sidewall routed to the bottom drain port of the drain body sinks versus a conventional overflow port. Because sinks having no integral tunnel for draining overflow water require a solid drain body, the user would simply leave the upper sidewall portion intact in order to use the drain with overflow knock-out blank drain body.

We claim: 
     
         1 . A sink drain comprising a longitudinal cylinder having a hollow core formed therein, said longitudinal cylinder containing a lower smooth surface portion, a middle portion with exterior threads, and an upper smooth surface portion terminating with a flange, said longitudinal cylinder having a given general wall thickness, said upper smooth surface portion having a removable sidewall knockout blank of a selected thickness less than said drain sidewall and having a perimeter having seam thinner than said knockout blank for easy breakage and removal of said sidewall portion. 
     
     
         2 . The sink drain defined in  claim 1  wherein said knockout blank includes an outer exterior surface recessed inward from an exterior surface of said drain sidewall.