Patent ID: 6874965

Claim:
A drywall finishing head for applying a mastic material over a tape joint between adjacent wallboard surfaces comprising: a coater having a body and a retaining assembly attached thereto for movably receiving a ball connected via an arm to a storage body for delivering mastic material through an opening in the ball to a mastic chamber in the coater body; a wiper blade extending substantially across a length of the coater body; a cover underlying the wiper blade and extending substantially across the length of the coater body; a curved backer bar extending substantially across the length of the coater body and overlying the wiper blade; and a cam assembly including an elliptical cam rotatably mounted on the retaining assembly and acting against a cam tensioner plate fixed behind the cam, the cam further acting on a tensioner wire having a central portion extending behind the retaining assembly and end portions wrapped around a front of the retaining assembly, the wire contacting a cam follower plate engageable with the backer bar, whereby adjustment of the cam assembly is constructed and arranged to change the force on the backer bar so that a proper crown or profile of mastic material can be delivered to the tape joint through a gap between the cover and the wiper blade.