Abstract: Apparatus for feeding perforated webs which has a form factor and cost which may be much less than conventional perforated paper feed mechanisms such as pinwheels and tractors, and in a preferred form is an elliptical path pin feed using an endless belt having pins which engage the perforations in the paper and a frame guides the belt over an elliptical path having major curved surfaces and minor curved surfaces along opposite sides and at the ends of the path, respectively. A sprocket journaled in the frame drives the belt. Guide members upstream and downstream of the web feed path and spaced from the opposite ends of one of the major surfaces guide the web so that it remains in contact with the belt along the major surface and enters and leaves the major surface along tangents thereto which are common to the major and minor end surfaces of the elliptical belt path.

Abstract: Web feeding apparatus which may be in the form of a tractor which feeds perforated webs, such as perforated paper in a computer printer, typewriter or the like has a frame which locates a belt having pins projecting from the belt which enter the perforations in the paper and drive the paper when the belt is driven, as by a sprocket which is journalled in the frame. In the closed position, the lid overlies the belt and presents a surface adjacent the belt which is separated by a gap through which the paper passes when it is engaged with the pins. The paper also overlies the surface of the inside side plate. The gap spacing (the distance which separates the surface of the belt on which the paper is disposed) is set automatically by a gap setting member which projects from the lid and is biased with the lid into engagement with the paper when the lid is in closed position and the belt is in driving relationship with the paper.

Abstract: An overhead unit used with a printer having a platen for feeding continuous, fan-folded, edge perforated forms. Tractors engage the feed perforations on the forms. The unit automatically bursts the side perforations by the use of flexural members which extract energy from the forms feed and oscillate to burst the side perforations. Bursting of the cross perforations is carried out by a pivotally mounted, lever actuated bar which engages the platen and forms a toggle therewith to engage the successive forms against the platen just below the cross perforations; the toggle being arranged to tighten and increase the clamping force, as the form is pulled away from the platen when bursting the cross perforations. A roller assembly including rollers engaging the outside of the loop on the infeed or upstream side of the platen removes any platen wave due to differential displacement of the forms as they travel with linear motion through the tractors and with rotational motion around the platen.

Abstract: A tractor for feeding perforated webs, such as perforated paper in a computer printer, typewriter or the like has a frame which locates a sprocket and a belt having pins projecting from the belt and lugs driven by the sprocket. To provide precision feeding of the web the lid is arranged with respect to the frame so that the web is maintained substantially at the pitch line of the belt where the pins enter, are engaged by and leave the perforations. The distance between the surface of the lid which faces the belt and the belt surface is limited such that the perforations contact the pin surface below a critical position where the web clings to the pins. This is the position where the angle between the surface of the belt and a line from the position of repose perpendicular to a tangent to pin surface which intersects the belt surface is equal to the art tangent of the coefficient of friction between the web and pin materials.

Abstract: An improved heat exchange tubing and blade assembly is described. The heat exchange assembly comprises an elongated tube and an elongated heat exchange blade strip positioned thereon. The heat exchange strip includes an array of integrally formed blade segments which extend from a U-shaped support segment of the strip. Surfaces of the blades extend at a favorable angle of attack to the incident fluid flow stream, and in a preferred embodiment the chords of the blades extend in a direction substantially normal to a longitudinal axis of the tube. The strip is supported on an outer surface of the tube, and a means integrally formed with the tube maintain the support segment in thermal contact with the tube.

Abstract: An improved heat exchange tubing and blade assembly and a method for fabricating the same are described. The heat exchange assembly comprises an elongated tube and an elongated heat exchange blade strip positioned thereon, said strip including an array of integrally formed blade segments which extend from a U-shaped support segment. Surfaces of the blades extend at a favorable angle of attack to the incident fluid flow stream, and in a preferred embodiment the chords of the blades extend substantially normal to the length of the tube. The strip is supported on an outer surface of the tube, and means integrally formed with the tube maintain the support segment in thermal contact with the tube.