Patent ID: 6152015
Filing Date: 2000-11-28
Classification: F15B

Abstract:
A pneumatic actuator comprising:an external pneumatic cylinder comprising an extruded tubular body, said extruded tubular body defining a first piston chamber;at least one internal pneumatic cylinder located coaxially internal to and telescopically extendable from said external cylinder and comprising an extruded tubular body with a longitudinally extruded conduit and defining a second piston chamber, each end of said extruded tubular body of said internal cylinder having two axially spaced parallel end surfaces;a first external closure head closing a first base end of said external cylinder and a second external closure head slidably accepting said internal cylinder and closing a second opposite end of said external cylinder;a first inlet/outlet air port in said first external closure head arranged to admit and discharge air into and from said first piston chamber;a second inlet/outlet air port in said second external closure head arranged to admit and discharge air into and from said conduit; anda first piston slidable internal to said first piston chamber and forming a first closure head at a first end of said internal cylinder facing the first external closure head by sealingly contacting a first of the two parallel end surfaces of the first end and being spaced apart from a second of the two parallel end surfaces of the first end so as to provide a spaced air passage from said second inlet/outlet air port to said conduit.