with reference now to the exemplary drawings , and particularly to fig1 and 5 , there is shown a preferred golf club head 10 in accordance with the present invention . the club head 10 is similar to many cavity back club heads that are known in the art . the club head 10 includes a body 11 having a front striking face 15 that is bounded by a striking face perimeter 18 . the perimeter is proximate a heel 12 , a toe 13 , a sole 14 , a hosel 17 and a top line 16 . the striking face 15 is the portion of the body 11 that is used to make contact with a golf ball ( not shown ). the hosel 17 allows the club head 10 to be connected to a shaft and a grip ( not shown ), to form a complete golf club , as is known in the art . the body 11 also has a rear cavity 20 that is bounded by a cavity perimeter 19 , as shown in fig2 . as is typical of many cavity back irons , the preferred body 11 has a cavity wall 21 that forms the back side of the striking face 15 and that is substantially parallel to the striking face 15 . the cavity perimeter 19 is proximate to , and surrounds , the cavity wall 21 . the cavity perimeter 19 has a cavity rim 22 that extends substantially rearwardly from the cavity wall 21 and the striking face 15 , as shown is fig5 a . the cavity rim 22 surrounds the cavity 20 , as shown in fig2 . although a cavity back iron is shown and described , the invention described herein may apply to other irons having a sole bar , such as hollow - headed irons . the construction of the body 11 is such that a substantial amount of the weight is concentrated proximate the cavity perimeter 19 , hence a common description is “ perimeter weighted ,” or “ cavity back .” the preferred body 11 has perimeter weighting 25 that comprises a mass of material that extends rearwardly of the striking face perimeter 18 . the preferred perimeter weighting 25 may extend proximate the entire perimeter 18 , or a portion thereof , dependent on desired weight distribution characteristics . the perimeter weighting 25 includes a sole bar 26 , which is a concentrated mass that is located proximate the sole 14 so as to provide the desired weight distribution characteristics . as is known in the art , the perimeter weighting 25 may take various shapes as it wraps from the striking face 15 to the cavity wall 21 . fig2 a and 5 b show the preferred perimeter weighting 25 configuration , with a cavity transition 23 between the cavity rim 22 and the sole 14 . the transition 23 may be in the form of a radius or a series of degradations . the body 11 has a raised cavity center weight 27 that protrudes rearwardly from the cavity wall 21 and that is bordered by the cavity perimeter 19 on two sides and by cavity step downs 28 , 29 . alternatively , the cavity wall 21 could be substantially flat or have other shapes to create different performance characteristics and different weight distribution . the body 11 preferably is formed of a cast stainless steel . this material is preferred because of its ductility , its relative softness that contributes to good feel , its resistance to corrosion , its strength , and its ability to be investment cast . a variety of stainless steel products and other similar known materials alternatively could be used . as shown in fig1 and 4 , the body 11 has a slot 60 formed proximate the sole 14 . the slot 60 preferably extends longitudinally between the heel 12 and the toe 13 . the slot 60 is formed within the sole bar 26 , and it is defined by a slot wall 61 running on all sides of the slot 60 and a shoulder 68 . the slot 60 has a toe end 62 and a heel end 63 , as shown in fig4 . preferably , a plurality of cylindrical apertures 64 are formed proximate the slot 60 , as shown in fig4 a and 5a . the apertures 64 each have a proximal end 67 and a distal end 66 . the proximal end 67 is located proximate the slot shoulder 68 and the distal end 66 is located nearer to the cavity rim 22 . preferably , the distal end 66 of each aperture does not enter the cavity 20 . subject to manufacturing constraints , a further embodiment would have apertures extending into the cavity 20 , entering the cavity proximate the cavity rim 21 . the apertures 64 are preferably cylindrical in shape , and form conical sections at their distal ends 66 , as a result of the use of drill bits in manufacture . other similar shapes could be used . each aperture 64 is defined by an aperture wall 65 . preferably , the axis of each aperture 64 is parallel to the striking face 15 and substantially perpendicular to a plane defined by the sole 14 . the slot 60 and the apertures 64 may be formed by means known in the art . in the preferred embodiment , a slot 60 and a plurality of apertures 64 are cast into the body 11 and then machined and drilled to appropriate tolerances . the slot 60 and apertures 64 are sized and configured to receive an insert assembly 30 , as shown in fig1 and 2 . the preferred insert assembly 30 comprises a plug 31 and a plurality of cells 40 that are sized and configured to fit within the slot 60 and the apertures 64 . a preferred cell 40 is shown in fig3 . each cell 40 may include a sleeve 41 and a pin 42 , as separate units . when placed in an aperture , each sleeve 41 partially or totally encases a corresponding pin 42 . the sleeve 41 may form an air pocket 49 at one or both ends . the sleeve 41 has a top 44 , a bottom 45 , an inner wall 47 , an outer wall 48 , and a shoulder 43 . the interface between the outer wall 48 and the bottom 45 may be flared outwardly to assist in manufacturing . the shoulder 43 and inner wall 47 define a void 46 where the pin 42 may be inserted upon final assembly . the dimensions of the cell 40 , including the pin 42 and the sleeve 41 , can vary for different irons within a set of clubs , due to the different dimensions of the respective soles and sole bars for those different irons . the preferred sleeve 41 may be constructed using an elastomer , including thermoplastic materials such as urethane . the sleeve may be formed of a variety of materials known in the art , so long as the chosen material has a hardness and modulus of elasticity that are lower than that of the pin 42 , and so long as it is easy to manufacture . for example , the preferred material , urethane , is sufficiently elastic and can be injection molded , so that it is readily manufacturable . the preferred pin 42 may be constructed of stainless steel or a variety of similar materials that are known in the art , so long as the chosen material is sufficiently dense and has a relatively high modulus of elasticity . exemplary materials include steel , copper , bronze , tungsten and nickel , to name a few . the assembled cell 40 is inserted into a corresponding aperture 64 by means known in the art . when fully inserted , the sleeve 41 generally prevents the pin 42 from contacting the body 11 , so that there is minimal or no contact between the pin 42 and the body 11 . the preferred body 11 has five apertures 64 and five cells 40 , although that number may be varied based on the damping , stiffness , feel and weight distribution characteristics that are desired . the preferred cells 40 are held in place in the apertures by the plug 31 . the preferred plug 31 has a substantially flat inner wall 34 , a circumferential side wall 33 that extends around the plug 31 , and a generally curved sole portion 32 . when assembled , the inner wall 34 seats proximate the shoulder 68 , and it frictionally holds the cells 40 in place . the plug side wall 33 when assembled is proximate the slot wall 61 , and the plug sole 32 is proximate the sole 14 . the plug 31 preferably includes a set of ridges 36 , one on each side , as particularly shown in fig5 b . the slot 60 preferably has a recess 35 that runs longitudinally between the toe end 62 and heel end 63 . upon insertion into the slot 60 , pressure is applied to force the plug 31 to seat proximate the shoulder 68 . upon application of appropriate pressure , the ridges 36 are forced to deform so as to seat within the recesses 35 , thereby frictionally holding the plug 31 in place . as shown in fig5 b , the pin 42 is preferably separated from contact with the plug 31 by the sleeve 41 . the plug 31 protects the cells 40 from interaction with the ground . the plug 31 is preferably made of bronze , although other , similar materials also could be used . the plug 31 should be made of an appropriate material based on its hardness , durability and ductility , as appreciated by those skilled in the art . bronze , for instance , allows a sufficient level of ductility to allow an appropriate level of flexing . the final assembly process is to grind or otherwise remove the excess material from the plug 31 , so that the plug 31 lies flush with the sole 14 of the body 11 . as shown in fig6 a badge 51 may also be used , which is preferably seated on the cavity rim 22 as shown at location 50 . the preferred club head 10 has improved feel , improved vibration damping characteristics , and reduced stiffness , as compared to prior clubs in the art . further , the preferred club head 10 may have advantageous weight distribution properties . the apertures 64 formed within the sole bar 26 reduce the stiffness of the lower part of the club 10 due to the removal of material and the elimination of a singular mass of material . the removal of the material , by itself , can lead to improved feel . the use and placement of the cells 40 can also have a dramatic effect on the ability of the preferred club head 10 to absorb shock and to improve the feel . the cells 40 work in the following manner . when a golf ball ( not shown ) is struck by the club head , the collision generally causes vibration in the head . low frequency vibrations can be felt with the hands , and can be unpleasant . high frequency vibrations can be audible , and can lead to an unpleasant and inconsistent sound . with reference now to fig5 b , if the depicted club head 10 were moving to the right to contact a golf ball ( not shown ), the club head &# 39 ; s velocity would be slowed at impact . however , because the pins 42 are not fixedly attached to the body 11 , the momentum of the pins 42 would continue to drive them forwardly . the sleeves 41 would compress and cushion the deflection of the pins 42 , thereby keeping the pins separated from the body while at the same time absorbing some of the energy imparted on the club head 10 due to the collision with the ball . two major effects are caused by the configuration of the cells 40 . first , there are viscous effects . due to the material properties of the sleeve 41 , the sleeves are compressed and then released as the pins 42 rebound off of the sleeves 41 . second , there are frictional effects . after impact , upon the excitation of vibration modes and multiple deflections , the pins 42 are jostled around within the sleeves 41 , rubbing , sliding and shaking in the head like mini pistons . this contact between the sleeves 41 and the pins 42 caused by micro - motions also dissipates energy in the form of heat due to friction . the frictional effects may be greater than the viscous effects . with the preferred five cells 40 working simultaneously , energy is being removed by multiple sources . in a similar fashion , the plug 31 can also dissipate or absorb vibration . because the plug 31 preferably is constructed of a material that is different than the body 11 , those different materials can result in a further dissipation of energy . fig7 depicts a second embodiment of a golf club head 10 in accordance with the present invention . in this embodiment , a cartridge 70 is used with a club head body 11 that is substantially similar to the body shown in fig1 - 6 . in this second embodiment , the cartridge 70 functions to provide similar benefits to those described for the first embodiment . this includes viscous effects and frictional effects . the second embodiment preferably uses a substrate 71 that is inserted into a slot 77 having sides 78 . the slot 77 is preferably formed within the club head body , proximate the sole bar 26 . the slot 77 may vary in thickness , length and distance from the face , so as to allow various performance changes to the club head . further , the slot 77 may extend from the sole 14 to the cavity rim 22 , or some portion thereof . the substrate 71 preferably is constructed of bronze , although other conventional materials alternatively can be used , including metals such as aluminum or tungsten , or non - metals such as carbon fiber . the substrate 71 generally should be sufficiently durable and ductile . the preferred substrate 71 has a plurality of interstices 72 formed therein , which may be filled with a polymer , such as polyurethane , or other similar materials having a hardness and a modulus of elasticity that are lower than those of the body 11 , and that are easy to manufacture . for example , the preferred material , urethane , is sufficiently elastic and can be injection molded , so that it is readily manufacturable . the cartridge 70 has a toe end 74 , a heel end 75 , a top side 76 and a cartridge sole 73 . when assembled , the cartridge 70 is inserted into the slot 77 and is attached using means known in the art . the toe end 74 of the cartridge 70 is positioned proximate the toe 13 of the body , the heel end 75 is positioned proximate the heel 12 of the body 11 , and the cartridge sole 73 is positioned proximate the sole 14 of the body 11 . the top side 76 of the cartridge is positioned proximate the cavity 20 . if the slot 77 extends completely through to the cavity 20 , the cartridge 70 may also extend to the cavity 20 , or a portion thereof . the second preferred embodiment of fig7 provides many of the benefits of the first preferred embodiment of fig1 - 6 . in a manner similar to the preferred embodiment , the cartridge shown in fig7 a and 7 b can provide an improved club head feel , improved vibration damping characteristics , and reduced stiffness as compared to prior clubs in the art . the slot 77 formed within the sole bar 26 may reduce the stiffness of the lower part of the club 10 due to the removal of material and the elimination of a singular mass of material . the use of the cartridge 70 can also dramatically affect the ability of the club head 10 to absorb shock and to improve the feel . the substrate 71 , combined with the interstices 72 filled with a polymer , can help reduce vibration , due to the absorption of energy by the polymer , and due to the geometry of the slot 77 , which impedes vibration . fig8 depicts a third preferred embodiment of a golf club head 10 in accordance with the present invention . in this embodiment , a cartridge 80 is used with a club head body 11 that is substantially similar to the body shown in fig1 - 6 and the body shown in fig7 a and 7 b . in this third embodiment , the cartridge 80 functions to provide similar benefits to those described for the first and second embodiments . the third preferred embodiment preferably uses a substrate 81 that is inserted into a slot 87 having sides 88 . the slot 87 preferably is formed within the club head body , proximate the sole bar 26 , similar to the second embodiment shown in fig7 . the slot 87 may vary in thickness , length and distance from the face , so as to allow various performance changes to the club head . further , the slot 87 may extend from the sole 14 to the cavity rim 22 , or some portion thereof . the substrate 81 preferably is constructed of bronze , although various metals and other similar materials may alternatively be used , as are known in the art , similar to those mentioned for the second embodiment . the preferred substrate 81 may have a plurality of interstices 82 formed therein , which function to reduce the stiffness of the substrate 81 . like the second preferred embodiment , this cartridge 80 has a toe end 84 , a heel end 85 , a top side 86 and a cartridge sole 83 . when assembled , the cartridge 80 is inserted into the slot 87 and attached using means known in the art . the toe end 84 of the cartridge is positioned proximate the toe 13 of the body , the heel end 85 is positioned proximate the heel 12 of the body 11 , and the cartridge sole 83 is positioned proximate the sole 14 of the body 11 . the top side 86 of the cartridge is positioned proximate the cavity 20 . if the slot 87 extends completely through to the cavity 20 , the cartridge 80 may also extend to the cavity 20 , or a portion thereof . the third embodiment may have a sleeve 90 that is positioned proximate the cartridge 80 . the sleeve 90 is formed so that it has two planar sides 91 and a sleeve top 92 . when assembled , the sleeve 90 folds over the cartridge 80 . the sleeve top 92 mounts proximate the top side 86 of the cartridge 80 , and the sides 91 drape over the sides of the substrate 81 . the preferred sleeve 90 may have plurality of nubs 95 formed therein , which can provide improved performance characteristics . preferably , the nubs 95 are positioned on the surface of the sleeve 90 that lies proximate the body 11 . the nubs 95 reduce the surface area of contact between the cartridge 80 and body 11 . during ball contact , energy is more efficiently transferred to , and absorbed by , the preferred polymer sleeve 90 . the third preferred embodiment provides many of the benefits of the other embodiments . in a manner similar to the other embodiments , the cartridge 80 shown in fig8 a and 8 b can improve club head feel , improve vibration damping characteristics , and reduce stiffness as compared to prior clubs in the art . the slot 87 formed within the sole bar 26 reduces the stiffness of the lower part of the club 10 due to the removal of material and elimination of a singular mass of material . the use of the cartridge 80 also can dramatically affect the ability of the club head 10 to absorb shock and to improve the feel . the substrate 81 , combined with the interstices 82 , which may be filled with a polymer or left as a void , can help reduce vibration , due to the absorption of energy by the polymer , and due to the geometry of the slot 87 , which impedes vibration . the use of the sleeve 90 provides an additional layer of material to absorb vibration . although the invention has been disclosed in detail with reference only to the preferred embodiments , those skilled in the art will appreciate that golf club heads can be made without departing from the scope of the invention . accordingly , the invention is defined only by the claims set forth below .
a golf club head is disclosed that comprises a body having a striking face and a sole , wherein a recess is formed in the sole . an insert is located within the sole recess , the insert including a core and an intermediate layer that at least partially separates the core from the recess wall . the intermediate layer has a hardness and a modulus of elasticity that are less than that of the core , such that when the golf club head is used to strike a golf ball , the resulting vibrations are dissipated by compression of the intermediate layer and movement of the core with respect to the intermediate layer .