US 11,752,407 B2
Golf shaft system and golf shaft
Byron H. Adams, Indian Wells, CA (US); Blair M. Philip, Dallas, TX (US); Jeffrey T. Halstead, Wylie, TX (US); Robert E. Stephens, Fort Worth, TX (US); and Trever M. Napier, Plano, TX (US)
Assigned to BREAKTHROUGH GOLF TECHNOLOGY LLC, Dallas, TX (US)
Filed by Breakthrough Golf Technology LLC, Dallas, TX (US)
Filed on Jun. 13, 2022, as Appl. No. 17/838,957.
Application 17/838,957 is a continuation of application No. 17/101,136, filed on Nov. 23, 2020, granted, now 11,358,041.
Application 17/101,136 is a continuation of application No. 16/721,025, filed on Dec. 19, 2019, granted, now 10,857,433, issued on Dec. 8, 2020.
Application 16/721,025 is a continuation in part of application No. 16/237,894, filed on Jan. 2, 2019, granted, now 10,729,952, issued on Aug. 4, 2020.
Application 16/237,894 is a continuation of application No. 15/884,683, filed on Jan. 31, 2018, granted, now 10,213,666, issued on Feb. 26, 2019.
Prior Publication US 2022/0314083 A1, Oct. 6, 2022
Int. Cl. A63B 53/10 (2015.01); A63B 53/12 (2015.01); A63B 60/08 (2015.01); A63B 60/26 (2015.01); A63B 53/00 (2015.01)
CPC A63B 53/10 (2013.01) [A63B 53/007 (2013.01); A63B 53/12 (2013.01); A63B 60/08 (2015.10); A63B 60/26 (2015.10); A63B 53/005 (2020.08); A63B 2209/00 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A golf club shaft, comprising:
a shaft having a shaft distal end, a shaft proximal end, a shaft outer diameter, a shaft length, a shaft mass, a shaft center of gravity located a shaft CG distance from the shaft proximal end, a kickpoint located a kickpoint distance from the shaft proximal end, wherein each point along the shaft length has (i) a shaft flexural rigidity including a maximum shaft flexural rigidity, and (ii) a shaft torsional rigidity including a maximum shaft torsional rigidity;
the shaft having a butt portion joined by a coupler to a tip portion;
the butt portion having a butt portion distal end, a butt portion proximal end, a butt portion length of 20-40″, and a butt portion mass of no more than 60 grams;
the tip portion having a tip portion distal end, a tip portion proximal end, a tip portion length that is (a) 8-26″, (b) 25-75% of the butt portion length, and (c) at least 20% of the shaft length, and a tip portion mass of no more than 35 grams and less than 75% of the butt portion mass;
the butt portion formed of a butt portion material having a butt material density, a butt portion mass, a butt portion elastic modulus, a butt portion shear modulus, and each point along the butt portion length having (i) a butt portion area moment of inertia, (ii) a butt portion polar moment of inertia, (iii) a butt portion flexural rigidity including an average butt portion flexural rigidity, a maximum butt portion flexural rigidity, and a minimum butt portion flexural rigidity, and (iv) a butt portion torsional rigidity including an average butt portion torsional rigidity, a maximum butt portion torsional rigidity, and a minimum butt portion torsional rigidity;
the tip portion formed of a tip portion material having a tip material density, a tip portion elastic modulus, and a tip portion shear modulus, and each point along the tip portion length having (i) a tip portion area moment of inertia, (ii) a tip portion polar moment of inertia, (iii) a tip portion flexural rigidity including an average tip portion flexural rigidity, a maximum tip portion flexural rigidity, and a minimum tip portion flexural rigidity, and (iv) a tip portion torsional rigidity including an average tip portion torsional rigidity, a maximum tip portion torsional rigidity, and a minimum tip portion torsional rigidity;
wherein:
the average tip portion flexural rigidity is 10-50 N*m2 and the average tip portion torsional rigidity is 5-40 N*m2;
the flexural rigidity of a portion of the shaft located 5-36″ from the shaft proximal end is at least 100% greater than the minimum tip portion flexural rigidity, and at least 50% greater than the minimum butt portion flexural rigidity; and
the maximum shaft flexural rigidity is no more than 600 N*m2 and the maximum shaft torsional rigidity is no more than 450 N*m2.