Mannesmann Aktiengesellschaft

Hermann Josef Frentzen

Ewald Henn

Richard Gerretz

Alfred Lampe

Hans Georg Ritter

Fritz Wittek

Gheorghe Arnatu

Gerhard Hendrix

Manfred Huppertz

Seamless tubes are manufactured from a hollow ingot introduced into a continuous-tube rolling mill. The hollow ingot is deformed, directly before introduction into a first stand of the rolling mill, so that without reduction in wall thickness the clearance between a mandrel and an inner surface of the hollow ingot in the region of a base of the groove of the rolls of the first stand is greater than the clearance in the region of roll flanks of the first stand. This advantageously increases the stretch in the first roll groove so that, on one hand, the total stretch limit can be increased and, on the other hand, the central roll groove can be relieved.

Method and apparatus for manufacturing seamless tubes

A mechanical pipe expander for a step-by-step expanding of steel pipes formed with a spiral welded seam. The expander includes an expander head that performs the expanding made up of circumferentially arranged segments over which the pipe assumes a circumjacent position and after which the segments move radially outward to forcibly engage the inside of the pipe. In order to avoid the segments contacting the inside welded seams of the pipe, the segments are formed with one or more complementary spiral slots and if the pipe has cross welded seams with one or more corresponding cross spiral slots.

Mechanical tube expander

A hold down device is disclosed suitable for an edge planing machine for working sheet metal. The hold down device has a plurality of hold down elements arranged in the direction of movement of the sheet metal and in a laterally overlapping relation. A plurality of piston cylinder units are provided and a single hydraulic cylinder is associated with and connected to each element for pressing it down against the sheet metal to be worked. The lateral surfaces of the elements facing the plate edge are in alignment with each other. The piston rod of the hydraulic drives are connected to the middle of each element for swivel action. The individual elements may either have an essentially rhomboidal or Z-shaped plan view. A further improvement adds spring forces and guidance to the hold down action.

Edge working machine with hold down for sheet metal to be worked

Growing community of inventors

Rheydt, Germany

Hermann Josef Frentzen