US 12,290,726 B2
Golf shaft
Kosuke Fujiwara, Yokohama (JP); and Akihisa Inoue, Yokohama (JP)
Assigned to NHK SPRING CO., LTD., Yokohama (JP)
Appl. No. 17/298,179
Filed by NHK SPRING CO., LTD., Yokohama (JP)
PCT Filed Oct. 18, 2019, PCT No. PCT/JP2019/041117
§ 371(c)(1), (2) Date May 28, 2021,
PCT Pub. No. WO2020/129387, PCT Pub. Date Jun. 25, 2020.
Claims priority of application No. 2018-240263 (JP), filed on Dec. 21, 2018.
Prior Publication US 2022/0111271 A1, Apr. 14, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. A63B 53/10 (2015.01); A63B 53/12 (2015.01)
CPC A63B 53/10 (2013.01) [A63B 53/12 (2013.01)] 5 Claims
OG exemplary drawing
 
1. A golf shaft comprising:
an element tube made of steel;
an outer layer made of a fiber reinforced plastic and covering an outer periphery of the element tube over an entire length of the element tube in an axial direction;
an adhesive layer interposed between the element tube and the outer layer to bond between the element tube and the outer layer, wherein
the outer layer comprises cured prepreg sheets wound around the element tube over the adhesive layer, resin being impregnated into each of the prepreg sheets,
weight of a whole including the element tube, the outer layer, and the adhesive layer is 50 g-130 g,
weight of the element tube is 50%-90% of the weight of the whole, and
a wall thickness of the outer layer alters in the axial direction and a wall thickness of the element tube alters in the axial direction.