DETROIT - A German inventor with a love for the game of ice hockey has come up with a novel design for a skate blade that never needs sharpening. After a decade of development work, Holger Wurthner introduced his new T'blade design this year at a sporting goods trade fair in Munich, Germany, and a rapid prototyping exhibition near Detroit. Wurthner was an announcer for a professional hockey team in Germany and has two sons who are professional players.
His T'blade, marketed by Wurthner Sport-Technologie of Villingen Schwenningen, Ger-many, is a novel, three-piece design incorporating a replaceable, plastic-metal blade se-cured to an injection molded base with a metal stabilizer. The T'blade skater can change the blade by removing the stabilizing rib, which is attached to the blade base with six screws.
A conventional hockey skate incorporates a steel blade in a plastic base. The exposed edge of the steel blade is hollow ground, allowing the skater to glide across the ice on two sharp edges.
The physics are the same for any type of blade. Skating friction heats the blade as it travels across the surface of the ice. As the edges push into the ice, the heated blade melts a thin layer of water, allowing the skate to glide across the surface.
According to Wurthner's de-scription, the plastic-metal composite is more efficient at retaining heat than the steel blade. Because the composite stores heat, it requires about 40 percent less work from the skater, Wurthner claims.
What's more, the replaceable blade eliminates the need for the frequent grinding necessary to sharpen all-steel blades.
After arriving at the general concept for the T'blade, Wurth-ner enlisted the help of Frog-design, a Sunnyvale, Calif.-based industrial design and product development firm, for final design and engineering.
Also included in the development effort was Contour Inc., a rapid prototyping service bureau based in Mountain View, Calif., which uses a system supplied by Cubital America Inc. of Troy, Mich.
In April, Cubital put the T'blade on display at its booth at the Rapid Prototyping & Manufactur-ing '96 show held in Dearborn, Mich.
Using computer-based engineering drawings from Frog-design, Contour produced two models of the T'blade in 14 hours at a cost of $1,700 per model. The models then were sanded, painted and metal plated and used for advertising photography and presentations to potential customers.
To produce the first functional models, Wurthner turned to N+H Klafky, a mold maker and injection molder based in Villingen Schwenningen.
Klafky built a tool in six weeks, allowing Wurthner to make its deadline for the Munich sporting goods show.
Wurthner plans to introduce the T'blade later this year in the United States and has priced the product - without the skate boot - at about $120.
For the plastics composite blade, Frogdesign specified a 0.4-millimeter, ultrahard strip of metal insert molded into a fiberglass-filled polyamide. The material combination provides impact resistance, good structural properties and very low water absorption, said Dirk Zimmermann, a Frogdesign industrial designer with the firm's office in Altensteig, Germany.
Both the metal strip and the polyamide share a similar rate of thermal expansion, important for a product that is in constant contact with water and ice.
The unique five-hole design of the blade support also is critical to establishing an easily recognizable product identity.
``Such a new, revolutionary system does need such a design,'' Zimmermann said.