Abstract: A gas cylinder with internal time delay which is entirely self contained within the cylinder. A valve pin that controls communication between the two sides of the piston through one or more a one-way valves in the piston. As each piston is moved by a die into the cylinder body, it exposes a portion of reduced cross section on a valve pin and gas flows through a one way valve such that the effective area of the piston is reduced. When the die moves away from the workpiece, a time delay occurs and the piston is delayed until the piston moves upwardly and closes communication between the sides of the piston.

Abstract: A method and apparatus for forming a strip of fins with louvers comprising providing fin forming rolls comprising stacked carbide plates having rolling and cutting edges forming fins with louvers, and directing a strip of clad aluminum between an opposed pair of fin forming rolls. The carbide plates are preferably made of carbide containing tungsten, cobalt and carbon, wherein the major constituent is tungsten.

Abstract: A die transfer system for transferring workpieces through successive die stations in a stamping press includes an enlongated finger bar having spaced fingers for engaging workpices at successive die stations, a first drive mechanism for reociprocating the finger bar longitudinally for transferring workpieces between successive die stations, and a second drive mechanism for reciprocating the finger bar laterally into and out of engagment with the workpieces at the die stations. The second drive mechanism has at least two finger bar drive modules coupled to the finger bar and spaced from each other lengthwise of the finger bar. A drive shaft extends between and interconnects the two drive modules. Each of the drive modules has a crank arm coupled to the drive shaft for rotating the crank arm about an axis parallel the finger bar. A cam plate is coupled to the finger bar and mounted for movement lateral to the crank arm axis and the finger bar.

Abstract: A transfer device for indexing workpieces through successive stations of a die in a stamping press is provided wherein the carriage and work engaging fingers are driven through separate drives actuated by the press ram. Each drive has an output shaft for operating the carriage and work engaging fingers, respectively. Each drive is compact and saves space by utilizing a plurality of links to drive the output shaft through 180.degree. of rotation so that desired accelertion and decelaration can be achieved. Each drive is a stand-alone mechanism adapted for use with existing transfer devices.

Abstract: A self-contained gas spring or die cylinder including a cylindrical housing having a closed end, an open end and a cylindrical bore. A cylindrical sleeve extends into the bore of the housing and has at least a portion thereof forming an internal cylindrical surface. A piston rod extends through an opening in the sleeve and has a piston thereon contacting the cylindrical surface. The piston rod is hollow and has a closed end in the portion thereof external of the cylindrical housing. The sleeve supports a first seal assembly adjacent the inner end of the rod and engaging the external surface of the rod, an intermediate slide ring on the sleeve and a secondary seal assembly on the sleeve positioned such that the slide ring is between the primary seal and the secondary seal.

Abstract: Rolls for forming convoluted heat exchanger strips having louvers in the successive convolutions. The rolls comprise a series of axially stacked upper and lower discs having intermeshing gear-like teeth around their periphery for forming convolutions in a metal strip and for cutting and forming the louvers therein. The cutting teeth have their opposite side faces beveled, the beveled face on the leading side of the tooth extending radially outwardly from the area of the crotch between teeth through the tip of the tooth. On the trailing side of each tooth the beveled face extends radially outwardly from more closely adjacent the vertex of the crotch to a point short of the tooth tip.