Mannesmann Aktiengesellschaft

Richard Gerretz

Hermann Josef Frentzen

Ewald Henn

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

The expander is constructed from an irregular, truncated polyhedral pyramid in which surfaces bounded by parallel edges alternate with surfaces of trapezoidal contour. The latter have T-shaped longitudinal grooves each receiving respectively the T-shaped foot portion of double T-contoured guide elements and being secured to the groove from axial ends of the pyramid.

Growing community of inventors

Viersen, Germany

Richard Gerretz