US 9,808,685 B1
Golf club head comprising glass bubble fill material
Joshua D. Westrum, San Diego, CA (US); Hong G. Jeon, Carlsbad, CA (US); and Scott Manwaring, Carlsbad, CA (US)
Assigned to Callaway Golf Company, Carlsbad, CA (US)
Filed by Callaway Golf Company, Carlsbad, CA (US)
Filed on Jul. 31, 2017, as Appl. No. 15/665,004.
Claims priority of provisional application 62/457,086, filed on Feb. 9, 2017.
Int. Cl. A63B 53/04 (2015.01); A63B 60/00 (2015.01)
CPC A63B 53/0475 (2013.01) [A63B 60/00 (2015.10); A63B 2060/002 (2015.10); A63B 2209/00 (2013.01)] 20 Claims
OG exemplary drawing
 
1. An iron-type golf club head comprising:
a body comprising a striking face, sole portion, top portion, rear portion, and cavity; and
a fill material at least partially filling the cavity,
wherein the fill material comprises a polymer material and a plurality of microscopic glass bubbles, and
wherein the plurality of microscopic glass bubbles constitutes 5% to 70% of a volume of the fill material.