Patent ID: 8424727

Claim:
A material dispensing assembly for converting a portable cartridge dispensing tool to a bag-type dispensing tool, the assembly comprising: a single piece piston for advancing material though a material housing, the single piece piston having a substantially square-shaped receptacle; a square shaped drive rack for attaching to said piston at said substantially square-shaped receptacle at a connection end and a plurality of teeth located thereon; and a support having a substantially square profile for receiving and supporting said drive rack during operation such that the construct of said drive rack and piston are prevented from rotating during operation; wherein said single piece piston further comprises first and second ends, the first end having a dome profile with an annular taper extending outwardly toward said second end and a circular seal lip integral with and extending from said annular taper about the perimeter of the piston, the circular seal lip comprising a plurality of substantially equal segments.