Patent ID: 8438967

Claim:
A piston assembly ( 100 ), comprising: a first piston portion ( 102 a ) including a substantially cylindrical head portion ( 103 a ), a mating face ( 105 a ) formed on the head portion ( 103 a ), and a substantially annular stiffness insert chamber ( 126 a ) formed in the mating face ( 105 a ) and adapted for receiving a portion of a substantially annular stiffness insert ( 120 ); a second piston portion ( 102 b ) including a substantially cylindrical head portion ( 103 b ), a mating face ( 105 b ) formed on the head portion ( 103 b ), and a substantially annular stiffness insert chamber ( 126 b ) formed in the mating face ( 105 b ) and adapted for receiving a portion of the substantially annular stiffness insert ( 120 ); and the substantially annular stiffness insert ( 120 ) clamped between the mating face ( 105 a ) of the first piston portion ( 102 a ) and the mating face ( 105 b ) of the second piston portion ( 102 b ).