Patent ID: 8474256

Claim:
A rocking beam drive mechanism for a machine comprising: a rocking beam having a rocker pivot; at least one cylinder comprising a closed end and an open end, the open end further comprising a linear bearing connected to the cylinder, the linear bearing having an opening to accommodate at least one coupling; at least one piston, the piston housed within a respective cylinder whereby the piston is capable of substantially linearly reciprocating within the respective cylinder; the at least one coupling having a proximal end and a distal end, the proximal end being connected to the piston and the distal end being connected to the rocking beam by an end pivot, wherein the linear bearing opening accommodates the coupling and whereby linear motion of the piston is converted to rotary motion of the rocking beam; a crankcase housing the rocking beam and housing a first portion of the coupling; a working space housing the at least one cylinder, the at least one piston and a second portion of the coupling; a lubricating fluid pump in the crankcase; and a seal sealably connected to the piston rod wherein the seal is a rolling diaphragm comprising non-woven fabric and wherein the seal maintains the lubricating fluid in the crankcase.