Cobra Golf Corporation

Cobra Golf Incorporated II

Hard Metals Partnership

Richard J Liesz

Christopher B Best

Robert D Hirsch

Mark McClure

Thomas Bernard Shappie

Robert A Sanford

David J Smith

A process of making an article of a tungsten-carbide-cobalt alloy with or without an additive of one or more of tantalum, cobalt-nickel, nickel-tantalum, tantalum-carbide, titanium-carbide, niobium-carbide, chromium-carbide, titanium-nitride and diamond dust. The method includes forming a homogeneous mixture of polygonal-shaped powder tungsten-carbide-cobalt and a polygonal-shaped powder additive and a binder including wax and a high molecular weight polyolefin polymer and injecting the mixture under heat and pressure into a metal injection mold to form a green preform of the article. The green preform is immersed in a linear hydrocarbon or a halogenated hydrocarbon or mixtures to dissolve and remove the wax and convert the green preform into a brown preform which is sintered to remove the remainder of the binder and to densify the brown preform into an article having a density not less than 98%. Various tungsten-carbide articles are disclosed.

Tungsten-carbide articles made by metal injection molding and method

A set of golf iron clubs is disclosed that, through unique structural features, provides excellent playing characteristics and enhances a player's ability to play accurate shots. Each club in the set has a head with a face angle of at least 1/2.degree. and a concentration of mass formed within the head. Face angles decrease sequentially from the longest iron in the set to the shortest iron in the set, while the Concentrations of mass also vary sequentially in location from a high heel location in the longest iron to being disposed further toward a sole and toe location in the shortest iron. The face angles are preferably at least 1.degree., more preferably in the range of 1/2.degree. to 5.degree., and most preferably in the range of about 1.degree. to about 31/2.degree.. Also disclosed are the individual clubs in the set. The shaft grip of each club also incorporates a reminder for enabling a golfer to maintain the striking face in proper alignment with the golf ball.

Golf club iron set having graded face angles and weight distribution

Golf club head

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Cardiff, CA, United States of America

Richard J Liesz