Abstract: A screw-rotor machine having a male rotor and a female rotor formed by a number of helical lobs or ribs and a like number of intervening helical grooves; the profiles of male rotor and female rotor are generated by a rack profile; wherein the rack profile is constructed by a plurality of line segments (or curves). Such that the screw-rotor machine is high in efficiency and the torque distribution can be adjusted.

Abstract: In a process for making a golf club head, an open hollow body is formed from metal to define a front striking panel, a bottom panel and a hollow neck section of the golf club head. The bottom panel extends rearwardly from a bottom end of the striking panel. The neck section is connected to the striking and bottom panels. A moldable closed hollow body is formed using a resin-impregnated fiber sheet material, and is positioned inside the open hollow body. An air bag is placed inside the closed hollow body. The open and closed hollow bodies are subsequently placed in a mold. The mold is heated, and air is blown into the air bag so as to pressurize the closed hollow body against inner surfaces of the open hollow body and the mold until the resin-impregnated fiber sheet material is cured.

Abstract: A golf club head includes a face frame defining a frame space, a supporting wall extending from the face frame, a fiber wall extending from and cooperating with a rear peripheral edge of the face frame and a peripheral edge of the supporting wall to confine an inner space thereamong, and a face panel received in the frame space and integrally connected to an inner face of the face frame which confines the frame space.

Abstract: A method for making a golf club head includes the steps of forming an open head body that includes a face frame and a supporting wall, forming a fiber wall that is integrally connected to and that cooperates with the face frame and the supporting wall to confine an inner space thereamong, and placing a face panel in the face frame and integrally connecting the face panel to an inner face of the face frame.

Abstract: In a process for making a golf club head, an open hollow body is formed from metal to define a front striking panel, a bottom panel and a hollow neck section of the golf club head. The bottom panel extends rearwardly from a bottom end of the striking panel. The neck section is connected to the striking and bottom panels. A moldable closed hollow body is formed using a resin-impregnated fiber sheet material, and is positioned inside the open hollow body. An air bag is placed inside the closed hollow body. The open and closed hollow bodies are subsequently placed in a mold. The mold is heated, and air is blown into the air bag so as to pressurize the closed hollow body against inner surfaces of the open hollow body and the mold until the resin-impregnated fiber sheet material is cured.

Abstract: A screw-rotor machine with two meshing rotors provides with helical lands and intervening grooves and adapted for rotation around parallel axes in a working space in the machine, characterized in that; the profile of rotors uses ellipse as a basic geometry generating curve on the male rotor.