Patent ID: 7427240

Claim:
A shaft for golf clubs wherein provided that: a position 130 mm away from the head-side end of the shaft is defined as a first position; a position 130 mm away from the grip-side end of the shaft is defined as a tenth position, and positions provided by equally dividing the length between the first position and the tenth position into nine regions are defined as from a second position to a ninth position in this order from the head side; each flexural rigidity EI measured at ten sites of from the first position to the tenth position is defined as from EI( 1 ) to EI( 10 ) in this order from the head side; each point obtained by plotting the measurement values at the positions of ten sites on an X-Y coordinate plane, in which the X-axis represents the distance (mm) to the measurement position from the head-side end and the Y-axis represents the value of flexural rigidity EI(N·m 2 ), is defined as from T( 1 ) to T( 10 ) in this order from the head side; the formula representing a line K that passes the T( 1 ) and the T( 10 ) on the X-Y coordinate plane is [Y=aX+b 1 ]; the values (N·m 2 ) at the Y-intercepts on the lines that are parallel to the line K and that pass the points of from T( 2 ) to T( 9 ), respectively, are defined as from b 2 to b 9 , respectively; and that the minimum value among the values at the Y-intercept b 2 to b 9 is defined as bmin, the following definition is made, the slope “a” of the line K is 0.04 or greater and 0.06 or less, any one of the b 3 , b 4 , b 5 , b 6 , b 7 and b 8 is smaller than b 1 , the bmin is any one of b 4 , b 5 , b 6 or b 7 , the value (b 1 −bmin) is 24 (N·m 2 ) or greater and 35 (N·m 2 ) or less, and the value (b 9 −b 1 ) is 0 or greater and 10 (N·m 2 ) or less.