Patent ID: 8079384

Claim:
A positioning assembly comprising: a spool seat having a chamber space therein, said chamber space having an inlet space defined by a channel formed in said chamber space, said channel having a end, said chamber space having an outlet space defined by a wall formed in said chamber space, said wall having a first curved portion and a second curved portion, said wall having a first inwardly extending portion and a second inwardly extending portion formed at opposite ends of and respectively between said first and second curved portions, each of said first and second inwardly extending portions having inwardly tapered generally planar sides with a section extending between ends of said generally planar sides, said channel having internal flanges extending upwardly from said end thereof, said wall of said outlet space having end portions at said first and second inwardly extending portions extending in generally parallel spaced relation to said flanges of said channel; and a ceramic disc positioned on said end of said channel and a portions received respectively between said flanges of said channel and said end portions of said first and second inwardly extending portions so as to prevent rotation of said ceramic disc with respect to said spool seat.