Air table

Claim 1

An improvement in an air table of the type having an article support surface with a plurality of openings therethrough, said surface comprising a plurality of juxtaposed sections along its length, a longitudinally extending air manifold, a source of pressurized air connected to said manifold and an air pipe for each section which laterally extends from said manifold beneath said surface and is in communication with the openings of the respective section, the improvement comprising: (a) valve means on each of said air pipes operable between open and closed positions to selectively deliver air from said mainfold through said air pipe to said openings; and (b) means on each of said sections and connected to said valve means thereon for selectively and independently actuating each of said valve means between said open and closed positions, said actuating means being responsive to an article on the respective section so as to maintain said article above said support surface while in transit between said sections, said air pipe including a longitudinally extending passageway defining a path of travel for said pressurized air and wherein said valve means is disposed in said passageway, said valve means being a pinch valve comprising a valve sleeve co-axially positioned in said air pipe and defining a chamber which is in flow communication with said passageway, a diaphragm secured within said chamber, an inlet on said sleeve in communication with said chamber, a source of fluid and a fluid line connecting said fluid source with said inlet whereby said diaphragm is selectively moved between an open position for air flow between said passageway and said chamber and thence to said openings and a constricted position to prevent said air flow, said actuating means including a means of sensing said article on said section and a fluid valve on said fluid line operable between open and closed position, said sensing means being connected to said fluid valve so that when said sensing means is actuated by said article, said fluid valve is moved to said closed position, thereby restricting the flow of fluid between said fluid source and said inlet to cause said diaphragm to move to said open position, and wherein said fluid valve is a slide valve having a valve housing defining a slide chamber, said housing having an intake opening in communication with said source of fluid and an outlet opening in communication with said inlet, a piston spring-biased within said chamber and having a passageway therethrough, said piston being movable from a first, normal position wherein the opposed ends of said passageway are in respective registration with said intake opening and said outlet opening and a second position wherein said opposed ends are out of said registration, and sensing means being connected to said position.