In a golf putter including a putter head including a head body formed from a metal, and a face insert formed from an elastic material and fixed in a putter face of the head body, the face insert includes a varied thickness portion increased in thickness from a zone adjacent a sweet spot of the head toward circumferential edges of the face insert.
1. A golf putter assembled with a putter head which consists essentially of: a head body formed from a metal; and a face insert which is formed solely from an elastic material and disposed in a putter face of the head body, and which includes a varied thickness portion having a thickness that increases in a direction from a zone adjacent a sweet spot to circumferential edges of said face insert which reduces the difference between hit feel upon impact with a golf ball in the zone adjacent to the sweet spot and hit feel upon impact with a golf ball in a location away from the zone adjacent to the sweet spot.
2. A golf putter as claimed in claim 1 , wherein said face insert is positioned to include at least a part of said zone adjacent the sweet spot, and includes a minimum thickness point, as the thinnest part thereof, in said zone adjacent the sweet spot, and
said varied thickness portion is varied in thickness along a toe-heel direction of said face insert.
3. A golf putter as claimed in claim 2 , wherein said varied thickness portion is varied in thickness along a top-sole direction of said face insert.
4. A golf putter as claimed in claim 3 , wherein values of (t 4 /t 1 ) and (t 5 /t 1 ) are 1.1 or more and 3 or less, provided that in said varied thickness portion of said face insert, t 1 denotes a thickness at said minimum thickness point, t 4 denotes a thickness at a point 5 mm toward the top side from said minimum thickness point, and t 5 denotes a thickness at a point 5 mm toward the sole side from said minimum thickness point.
5. A golf putter as claimed in claim 3 , wherein values of(t 4 /t 1 ) and (t 5 /t 1 ) are 1.2 or more and 3 or less, provided that in said varied thickness portion of said face insert, t 1 denotes a thickness at said minimum thickness point, t 4 denotes a thickness at a point 5 mm toward the top side from said minimum thickness point, and t 5 denotes a thickness at a point 5 mm toward the sole side from said minimum thickness point.
6. A golf putter as claimed in claim 3 , wherein values of (t 4 /t 1 ) and (t 5 /t 1 ) are 1.2 or more and 2.5 or less, provided that in said varied thickness portion of said face insert, t 1 denotes a thickness at said minimum thickness point, t 4 denotes a thickness at a point 5 mm toward the top side from said minimum thickness point, and t 5 denotes a thickness at a point 5 mm toward the sole side from said minimum thickness point.
7. A golf putter as claimed in claim 2 , wherein values of (t 2 /t 1 ) and (t 3 /t 1 ) are 1.2 or more and 11 or less, provided that in said varied thickness portion of said face insert, t 1 denotes a thickness at said minimum thickness point, t 2 denotes a thickness at a point 20 mm toward the toe side from said minimum thickness point, and t 3 denotes a thickness at a point 20 mm toward the heel side from said minimum thickness point.
8. A golf putter as claimed in claim 2 , wherein values of (t 2 /t 1 ) and (t 3 /t 1 ) are 1.5 or more and 5 or less, provided that in said varied thickness portion of said face insert, t 1 denotes a thickness at said minimum thickness point, t 2 denotes a thickness at a point 20 mm toward the toe side from said minimum thickness point, and t 3 denotes a thickness at a point 20 mm toward the heel side from said minimum thickness point.
9. A golf putter as claimed in claim 2 , wherein values of (t 2 /t 1 ) and (t 3 /t 1 ) are 2 or more and 3 or less, provided that in said varied thickness portion of said face insert, t 1 denotes a thickness at said minimum thickness point, t 2 denotes a thickness at a point 20 mm toward the toe side from said minimum thickness point, and t 3 denotes a thickness at a point 20 mm toward the heel side from said minimum thickness point.
10. A golf putter as claimed in claim 1 , said face insert having a JIS-A hardness of 88 to 96.
11. A golf putter assembled with a putter head comprising: a head body formed from a metal; and a face insert which is formed from an elastic material and disposed in a putter face of the head body, and which includes a varied thickness portion having a thickness that increases in a direction from a zone adjacent a sweet spot to circumferential edges of said face insert;
wherein said face insert is positioned to include at least a part of said zone adjacent the sweet spot, and includes a minimum thickness point, as the thinnest part thereof, in said zone adjacent the sweet spot;
wherein said varied thickness portion is varied in thickness along a toe-heel direction of said face insert;
wherein the face insert is formed solely from the elastic material;
wherein values of (t 4 /t 1 ) and (t 5 /t 1 ) are 1.2 or more and 2.5 or less, provided that in said varied thickness portion of said face insert, t 1 denotes a thickness at said minimum thickness point, t 4 denotes a thickness at a point 5 mm toward the top side from said minimum thickness point, and t 5 denotes a thickness at a point 5 mm toward the sole side from said minimum thickness point; and
wherein a cavity configured in conformity with the configuration of the face insert is formed in the putter face of the head body, the face insert is fixedly fitted in the cavity, and a bottom face of the cavity and a back face of the face insert contact with each other.
12. A golf putter as claimed in claim 1 , wherein the face insert extends continuously from heel to toe over most of the length of the putter face.
13. A golf putter as claimed in claim 11 , wherein the face insert extends continuously from heel to toe over most of the length of the putter face.