Patents by Inventor Walter Hellmann

Walter Hellmann has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 4917754
    Abstract: To coat a firm, closed surface having a peelable adhesive masking film thereon, the latter is lifted off the surface at one end and a low viscosity coating composition is poured into the wedge so formed. As the masking film is pulled off further, the wedge moves along the surface, which is thus coated. The coating composition in the wedge is replenished at the rate at which it is consumed.
    Type: Grant
    Filed: April 20, 1989
    Date of Patent: April 17, 1990
    Assignee: Rohm GmbH
    Inventors: Heinz Vetter, Walter Hellmann, Otmar Krajec
  • Patent number: 4664672
    Abstract: A process for transfer printing onto solid substrates made of plastics or having a surface layer of varnish or plastic is described. According to the invention described a sheet dye carrier at a temperature suitable for dye transfer is pressed to a preferably preheated surface and/or to a limited area of the surface to be printed by means of superatmospheric gas pressure, in particular by means of a flowing gas. Additionally the surface to be printed is maintained at a temperature below the thermoplastic range during the transfer process.
    Type: Grant
    Filed: March 10, 1986
    Date of Patent: May 12, 1987
    Assignee: Rohm GmbH Chemische Fabrik
    Inventors: Otmar Krajec, Walter Hellmann
  • Patent number: 4515648
    Abstract: What is disclosed is a method for making a gastight multiple-walled panel of extruded resin from an integrally extruded hollow panel comprising two parallel, plane outer walls having supporting partitions disposed between them and defining long hollow cells with open end faces, which method comprises heating the hollow panel at least in the area of the open end faces of said hollow cells until the resin is in the thermoplastic state, and then heat sealing the two outer walls in the thermoplastic area thereof in a gastight manner either to each other or to a tape of a further thermoplastic material covering the end faces, the seal so produced being held for at least 1 minute at a temperature ranging from 10.degree. C. beneath the Vicat softening point to 20.degree. C. above the Vicat softening point of the resin.
    Type: Grant
    Filed: December 15, 1982
    Date of Patent: May 7, 1985
    Assignee: Rohm GmbH
    Inventors: Klaus Kolbe, Walter Hellmann, Otmar Krajec, Hartmut Schikowsky, Heinz Vetter
  • Patent number: 4483814
    Abstract: A rigid, one-piece, thin-walled shaped body of stretched plastic whose edge is not in one plane and which has a surface approximating the mathematical minimal surface is disclosed which can be produced with increased dimensional accuracy. A plane plate made of a biaxially stretched plastic at least 1 mm thick is caused to assume a shape which is not in one plane, for example, the shape of a semicylindrical surface, and the edge of the plate is fixed or held in that position. On being heated to a temperature in the thermoelastic range, the surface partially shrinks back and results in a shape approximating the minimal surface, while backshrinkage of the edge is prevented by its being held in a fixed position. Opposite portions of the fixed edge, between which the plastic plate extends rectilinearly, before backshrinkage of the plastic plate sets in, are spaced farther apart after heating and then fixed anew prior to cooling.
    Type: Grant
    Filed: May 31, 1983
    Date of Patent: November 20, 1984
    Assignee: Rohm GmbH
    Inventors: Otmar Krajec, Walter Hellmann