Abstract: A portable radio device including a frequency synthesizer 5 for producing a local signal for radio section, a digital control circuit 6 for digitally controlling a portion of or the entirety of the radio device, and a reference signal generator 1 which operates the frequency synthesizer and the digital control circuit, wherein a buffer amplifier 2 is provided between the reference signal generator and the digital control circuit, and switching means 4 is provided in parallel with the buffer amplifier between the reference signal generator and the digital control circuit. When the frequency synthesizer is inactive, the switching means is activated, and a power supply 3 of the buffer amplifier is deactivated. As a result, the power dissipated by the buffer amplifier can be reduced without deteriorating the characteristics of the frequency synthesizer.

Abstract: A cavity iron golf club head being forme from a metal ingot by a rotary cutting tool that has a conical cutting section and a cylindrical cutting section which are formed into an integral unit in tow stages with the respective cutting surface angles differing from each other. An inner circumferential surface on the head sole side of an indentation formed in the back surface of the metal ingot which has been roughly finished and formed in cut into an overhanging surface shape by the conical cutting section and cylindrical cutting section of the rotary cutting tool, and the other inner circumferential surfaces on the toe and heel sides and on the top side of the metal ingot are cut into upright surface shapes by the cylindrical cutting section of the rotary cutting tool.

Abstract: A golf club with a ferrule mounted in the opening end of a club shaft insertion hole formed in the hosel of a club head. A plurality of recessed grooves are formed in the inner circumferential surface of the through-hole of the ferrule in which the tip-end of the club shaft is press-fitted, and these recessed grooves are filled and coated with a bonding agent so that the ferrule is securely attached to the tip-end of the club shaft.

Abstract: In construction of a joint structure between a hosel, a shaft and a ferrule, a rugged engagement is formed between the hosel and the ferrule in order to withstand a force at shooting balls which tends to move the ferrule apart from the hosel. The rugged engagement consists of at least one projection formed on one of the ferrule and the hosel and a recess formed in the other of the ferrule and the hosel.

Abstract: In construction of a golf club in which a shaft is fixed along its lower tip to a main body within a shaft hole formed in a hosel of the main body, an elongated cylindrical core is inserted into the lower tip of the shaft whilst projecting beyond the upper end location of the hosel. Presence of the cylindrical core well fortifies a shaft/hosel joint whilst withstanding impact is generated at shooting balls.

Abstract: In construction of a wood club head having a main body of a hollow metallic shell construction, the face thickness is limited to 2 to 4 mm and the entire head volume is limited to 190 cc or larger for enlargement of its sweet spot. The enlarged sweet spot assures a long flying distance of a ball in an intended direction through its improved mating with the ball at the very moment of striking.

Abstract: In construction of a shell-type wood golf club head, at least its crown is made of a material of a rigidity lower than that of a material forming the other sections of the club head. The crown exhibits upward elastic deformation upon striking a ball and allows the face to incline rearwards, thereby providing a temporarily increased loft which suppresses undesirable back spin of the balls and assures longer shots and smooth run of the balls after landing.

Abstract: A hollow metallic wood club head formed of a superplastic metallic material to have a crown portion, a hitting face portion and a sole portion, wherein the rigidity of the crown portion is determined to be lower than that of the sole portion so that the loft angle of the face portion is increased at the moment of impact against a golf ball in an angle range of 0.5.degree.-2.5.degree., and wherein the metallic average grain size of the crown portion is determined to be less than 50 micron.

Abstract: For improvement in aerodynamic characteristics of a golf club head at swing, the transverse cross-section of the hosel is defined by a winged profile which includes at least one of a convex heel and concave toe sections. The sole face is defined by a convex sphere of a specified radius of curvature. The crown and sole faces are defined with vertical symmetry by respective convex spheres of similar radii of curvature. Current transition around the club head at swing is well prevented for higher head speed. Bias buoyancy at swing are minimized for a stabilized swing line.