Patent ID: 7587971

Claim:
A rodless pneumatic cylinder comprising: a piston assembly; a body; a first aperture and an associated first airflow channel defined in the piston assembly; a second aperture and an associated second airflow channel defined in the piston assembly; a working volume defined in the body; a piston, defined in the piston assembly, and disposed in the working volume to separate the working volume into a first working volume and a second working volume, wherein the piston is arranged to enable a difference in air pressure between the first working volume and the second working volume to produce a differential force on the piston assembly, wherein a first distance from the first aperture to the piston remains constant during a movement of the piston and a second distance from the second aperture to the piston remains constant during the movement of the piston; a first end cap operatively coupled to the body, the first end cap having an inner planar surface and a cylindrical portion having an inner cylindrical surface, wherein the inner cylindrical surface defines a perimeter of a three dimensional space; a first acoustical foam snubber operatively coupled to the first end cap, wherein the first acoustical foam snubber fills the three dimensional space, the first acoustical foam snubber having a planar surface area made of foam, wherein the planar surface area made of foam is exposed to the working volume defined in the body, the first acoustical snubber being configured to diffuse a first sound wave associated with air moving in the first working volume when the air contacts the first acoustical snubber; and an air control device operatively coupled to the piston assembly, the air control device being located outside the working volume, the air control device being positioned to travel with the piston assembly when the differential pressure is effected on the piston, the air control device being structured to (a) direct air into the first working volume through the piston assembly via the first aperture, (b) to direct air out of the second working volume through the piston assembly via the second aperture, (c) direct air into the second working volume through the piston assembly via the second aperture, and (d) direct air out of the first working volume through the piston assembly via the first aperture, wherein the active air control device includes a pressure sensor and a servo valve.