Iron type golf club head

Abstract

Iron-type golf club heads are disclosed having a heel portion, a sole portion, a toe portion, a top-line portion, a front portion, a rear portion, and a striking face. The iron-type golf club heads include a flexible boundary structure (“FBS”) that is provided at one or more locations on the club head. The flexible boundary structure may comprise, in several embodiments, a slot, a channel, a gap, a thinned or weakened region, or other structure that enhances the capability of an adjacent or related portion of the golf club head to flex or deflect and to thereby provide a desired improvement in the performance of the golf club head.

1 - 11 . (canceled) 
     
     
         12 . An iron-type golf club head of claim, comprising:
 an iron-type body having a heel portion, a toe portion, a top-line portion, a face portion having a variable face thickness varying from a minimum face thickness to a maximum face thickness, a sole portion extending rearwardly from a lower end of said face portion, and the body defines a cavity behind the face portion including a lower cavity region wherein:
 the face portion includes an ideal striking location that defines the origin of a coordinate system in which an x-axis is tangential to the face portion at the ideal striking location and is parallel to a ground plane when the body is in a normal address position, a y-axis extends perpendicular to the x-axis and is also parallel to the ground plane, and a z-axis extends perpendicular to the ground plane, wherein a positive x-axis extends toward the heel portion from the origin, a positive y-axis extends rearwardly from the origin, and a positive z-axis extends upwardly from the origin; 
   the face portion defines a striking face plane that intersects the ground plane along a face projection line;   the body includes a central region which extends along the x-axis from a location greater than about −25 mm to a location less than about 25 mm,   the sole portion contained within the central region includes a thinned forward sole region located adjacent to the face portion and a thickened rearward sole region located behind the thinned forward sole region, with the thinned forward sole region defining a wall having a minimum forward sole thickness T FS  and the thickened rearward sole region having a maximum sole bar thickness T SB ;   
       at least one vertical section within the central region and parallel to the y-axis has (a) the minimum forward sole thickness T FS  no more than 3.0 mm and less than the maximum face thickness, (b) the maximum sole bar thickness T SB  at least 7.0 mm, and (c) a ratio of the minimum forward sole thickness T FS  to the maximum sole bar thickness T SB  is 0.04-0.50:
 wherein the lower cavity region separates the thickened sole region from a rear surface of the face and the lower cavity region is at least partially defined by a rear surface of the face, the thinned forward sole region, and the thickened rearward sole region. 
 
     
     
         13 . The iron-type golf club head of  claim 12  further comprising a back wall enclosing the cavity, wherein the back wall extends from a first portion of the iron-type golf club head proximate the top-line portion to a second portion of the iron-type golf club head proximate the thickened sole region. 
     
     
         14 . The iron-type golf club head of  claim 13 , wherein the cavity is at least partially hollow. 
     
     
         15 . The iron-type golf club head of  claim 14 , wherein the cavity is at least partially filled with a filler material. 
     
     
         16 . The iron-type golf club head of  claim 14 , wherein the cavity is filled with a filler material. 
     
     
         17 . The iron-type golf club head of  claim 12 , wherein the cavity includes a vibration dampening insert, the vibration dampening insert contacts the rear surface the face. 
     
     
         18 . The iron-type golf club head of  claim 14 , wherein the cavity includes a vibration dampening insert, the vibration dampening insert contacts the rear surface the face. 
     
     
         19 . The iron-type golf club head of  claim 13 , wherein the back wall includes an aperture and a vibration dampening insert is installed into the cavity through the aperture, and the vibration dampening insert contacts the rear surface the face. 
     
     
         20 . The iron-type golf club head of  claim 13 , wherein the back wall includes an inner back wall surface that defines a portion of the cavity and forms a back wall thickness between an outer back wall surface that defines an outer portion of the iron-type golf club head. 
     
     
         21 . The iron-type golf club head of  claim 20 , wherein the back wall thickness ranges between about 0.5 mm to about 4 mm. 
     
     
         22 . The iron-type golf club head of  claim 20 , wherein the back wall thickness varies. 
     
     
         23 . The iron-type golf club head of  claim 12 , wherein the variable face thickness is asymmetrical. 
     
     
         24 . The iron-type golf club head of  claim 12 , wherein the variable face thickness is asymmetrical such that the thickness of the face portion proximate to the thinned forward sole region is less than the thickness of the face portion distal to the thinned forward sole region. 
     
     
         25 . The iron-type golf club head of  claim 12 , wherein the cavity includes an undercut recess around a periphery of the iron-type golf club head. 
     
     
         26 . The iron-type golf club head of  claim 12 , wherein the face portion includes a striking plate welded to the iron-type body and the striking plate is formed from a first steel alloy and the iron-type body is formed from a second steel alloy. 
     
     
         27 . The iron-type golf club head of  claim 15 , wherein the first steel alloy is a precipitation hardened stainless steel alloy and the second steel alloy is a carbon steel alloy. 
     
     
         28 . The iron-type golf club head of  claim 15 , wherein the first steel alloy is a chrome-molybdenum steel alloy and the second steel alloy is a carbon steel. 
     
     
         29 . The iron-type golf club head of  claim 12 , wherein the lower cavity region comprises a first lower cavity region located forward of the maximum sole bar thickness and a second lower cavity region located rearward of the maximum sole bar thickness. 
     
     
         30 . The iron-type golf club head of  claim 21 , wherein the lower cavity region comprises a first lower cavity region located forward of the maximum sole bar thickness and a second lower cavity region located rearward of the maximum sole bar thickness. 
     
     
         31 . The iron-type golf club head of  claim 12 , wherein the lower cavity region has a lower cavity width defined as a distance between the rear surface of the face and the thickened rearward sole region as measured along a y-axis, wherein the lower cavity width varies and decreases proximate to the thinned forward sole region and increases distal to the thinned forward sole region.