# Patent

## Title
Grooves of golf club heads and methods to manufacture grooves of golf club heads

## Abstract

Embodiments of grooves of golf club heads and methods to manufacture grooves of golf club heads are generally described herein. The golf club heads include a club face defined by a toe end, a heel end, a top rail and a sole. The golf club heads further include a plurality of grooves disposed on the club face between the top rail and the sole. Each groove extends between a heel end and a toe end. Depths of the grooves vary in a direction extending between the top rail and the sole and in a direction extending between the heel end and the toe end. Widths of the grooves vary in a direction extending between the heel end and the toe end.

## Background
RELATED APPLICATIONS
The present application is a continuation in part of U.S. patent application Ser. No. 14/196,313, filed on Mar. 4, 2014, which is a continuation in part of U.S. patent application Ser. No. 13/761,778, filed on Feb. 7, 2013, which is a continuation of U.S. patent application Ser. No. 13/628,685, filed on Sep. 27, 2012, which claims the benefit of U.S. Provisional Patent Application Ser. No. 61/697,994, filed on Sep. 7, 2012 and U.S. Provisional Patent Application Ser. No. 61/541,981 filed on Sep. 30, 2011, all of which are incorporated herein by reference.


FIELD
The present disclosure relates generally to golf equipment, and more particularly, to grooves of golf club heads and methods to manufacture grooves of golf club heads.
BACKGROUND
Typically, a golf club head may include a club face with a plurality of parallel grooves extending between the toe end and the heel end. In particular, the plurality of grooves in an iron-type club head may clear out water, sand, grass, and/or other debris between a golf ball and the club face. Golf club faces may have grooves with various shapes such as squared or box-shaped grooves, V-shaped grooves, or U-shaped grooves.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a putter according to one example.
FIG. 2 shows a schematic diagram of a ball striking face of a putter according to one example.
FIG. 3 shows a schematic diagram of a ball striking face of a putter according to one example.
FIG. 4 shows a schematic top view of a groove of the ball striking face of FIG. 3.
FIG. 5 shows a horizontal cross-sectional diagram of the groove of FIG. 4 taken at section 5-5 of FIG. 3.
FIG. 6 shows a horizontal cross-sectional diagram of another groove of the ball striking face FIG. 3.
FIG. 7 shows a horizontal cross-sectional diagram of another groove of the ball striking face FIG. 3.
FIG. 8 shows a schematic diagram of a ball striking face of a putter according to one example.
FIG. 9 shows a schematic top view of a groove of the ball striking face of FIG. 8.
FIG. 10 shows a horizontal cross-sectional diagram of the groove of FIG. 9 taken at section 10-10 of FIG. 8.
FIG. 11 shows a horizontal cross-sectional diagram of another groove of the ball striking face FIG. 8.
FIG. 12 shows a horizontal cross-sectional diagram of another groove of the ball striking face FIG. 8.
FIG. 13 shows a schematic diagram of a ball striking face of a putter according to one example.
FIG. 14 shows a schematic top view of a groove of the ball striking face of FIG. 13.
FIG. 15 shows a horizontal cross-sectional diagram of the groove of FIG. 14 taken at section 15-15 of FIG. 13.
FIG. 16 shows a horizontal cross-sectional diagram of another groove of the ball striking face FIG. 13.
FIG. 17 shows a horizontal cross-sectional diagram of another groove of the ball striking face FIG. 13.
FIG. 18 shows a schematic diagram of a ball striking face of a putter according to one example.
FIG. 19 shows a schematic top view of a groove of the ball striking face of FIG. 18.
FIG. 20 shows a horizontal cross-sectional diagram of the groove of FIG. 19 taken at section 20-20 of FIG. 18.
FIG. 21 shows a horizontal cross-sectional diagram of another groove of the ball striking face FIG. 18.
FIG. 22 shows a horizontal cross-sectional diagram of another groove of the ball striking face FIG. 18.
FIG. 23 shows a schematic diagram of a ball striking face of a putter according to one example.
FIGS. 24-26 show different examples of vertical cross sections of grooves of the ball striking face of FIG. 23 taken at section 24-24 of FIG. 23.
FIG. 27 shows a schematic diagram of a ball striking face of a putter according to one example.
FIG. 28 shows a schematic diagram of a ball striking face of a putter according to one example.
FIGS. 29-37 show schematic diagrams of exemplary horizontal cross sections of a groove of a ball striking face of a putter.
FIGS. 38-45 show schematic top views of exemplary grooves of a ball striking face of a putter.
FIG. 46 shows a schematic diagram of a ball striking face of a putter according to one example.
FIG. 47 shows a schematic diagram of a ball striking face of a putter according to one example.
FIG. 48 is a horizontal cross-sectional view of a groove of a putter according to one example.
FIG. 49 shows a vertical schematic cross-sectional diagram of a putter according to one example.
FIG. 50 shows a vertical schematic cross-sectional diagram of a putter according to one example.
FIG. 51 shows a putter face according to another example.
FIG. 52 shows a putter face according to another example.
FIG. 53 shows a method of manufacturing a golf club according to one example.
FIG. 54 shows a schematic diagram of a ball striking face of a putter according to one example.
FIG. 55 shows a cross section of a groove of the ball striking face of FIG. 54.
FIG. 56 shows a schematic diagram of a ball striking face of a putter according to one example.
FIG. 57 shows a cross section of a groove of the ball striking face of FIG. 56.
FIG. 58 shows a schematic diagram of a ball striking face of a putter according to one example.
FIG. 59 shows a cross section of a groove of the ball striking face of FIG. 58.
FIG. 60 shows a schematic diagram of a ball striking face of a putter according to one embodiment.
FIG. 61 shows a schematic top view of a groove of the ball striking face of FIG. 60.
FIG. 62 shows a horizontal cross-sectional diagram of the groove of FIG. 61 taken at section 62-62 of FIG. 60.
FIG. 63 shows a tool for cutting a groove.
FIG. 64 shows a V-shaped groove according to one example.
FIG. 65 shows a V-shaped groove according to one example.
FIG. 66 shows a schematic top view of a groove according to one example.
FIG. 67 shows a horizontal cross-sectional diagram of the groove of FIG. 66.



DESCRIPTION
In general, grooves of golf club heads and methods to manufacture grooves of golf club heads are described herein. Golf equipment related to the methods, apparatus, and/or articles of manufacture described herein may be conforming or non-conforming to the rules of golf at any particular time. Further, the figures provided herein are for illustrative purposes, and one or more of the figures may not be depicted to scale. The apparatus, methods, and articles of manufacture described herein are not limited in this regard.
In the examples of FIG. 1, a putter 100 is shown. Although grooves for a putter 100 are described herein, the apparatus, methods, and articles of manufacture described herein may be applicable other types of club head (e.g., a driver-type club head, a fairway wood-type club head, a hybrid-type club head, an iron-type club head, etc.). For example, grooves for iron-type club heads are described in detail in U.S. Patent Application Publication US 2010/0035702, filed Aug. 5, 2009, the entire disclosure of which is expressly incorporated by reference. Accordingly, any reference made herein to a putter may include any type of golf club.
The putter 100 includes a putter head 102 having a putter face 110. The putter face 110 may be generally planar. The putter face 110 includes a ball striking face 112 that may be generally on the same plane as the putter face 110 or slightly projected outward from the putter face 110. The ball striking face 112 may be the same size or smaller (as shown in FIG. 1) than the putter face 110. The ball striking face 112 may be a region on the putter face 110 that is generally used to strike a golf ball (not shown). However, an individual may also strike a ball with a section of the putter face 110 that is outside the ball striking face 112.
The ball striking face 112 may be a continuous or integral part of the putter face 110 or formed as an insert that is attached to the putter face 110. Such an insert may be constructed from the same material or different materials as the putter face 110 and then be attached to the putter face 110. The ball striking face 112 may include one or more grooves, generally shown as grooves 120, and one or more land portions 170. For example, the ball striking face 112 is shown to have twelve grooves, generally shown as 122, 124, 126, 128, 130, 132, 134, 136, 138, 140, 142, and 144. The grooves 120 may be generally referred to with a single reference number such as 120. However, when specifically describing one of the grooves on the ball striking face 112, the reference number for that specific groove may be used.
Two adjacent grooves may be separated by a land portion 170. A land portion 170 between each groove 120 and an adjacent groove 120 may have the same or different width as a land portion 170 between another pair of adjacent grooves 120. The land portions 170 may also define the top surface of the ball striking face 112. In general, two or more of the grooves 120 may be parallel to each other. For example, the grooves 122 and 124 may be parallel to each other. However, the grooves 120 may be oriented relative to each other in any manner. For example, any of the grooves 120 may be diagonally, vertically and/or horizontally oriented. As shown in the example of FIG. 2, one or more of the grooves 120 may be substantially linear and generally parallel to an adjacent groove 120 and extend between a toe end 180 and a heel end 190 of the putter face 110.
As described in detail below, the depth, length, width, a horizontal cross-sectional shape, and/or a vertical cross-sectional shape of the grooves 120 may linearly, nonlinearly, in regular or irregular step-wise intervals, arcuately and/or according to one or more geometric shapes increase, decrease and/or vary from the toe end 180 to the heel end 190 and/or from a top rail 182 to a sole 192 of the putter head 102. The apparatus, methods, and articles of manufacture described herein are not limited in this regard.
Referring to FIG. 2, the ball striking face 112 is shown having grooves 122-144. The ball striking face 112 may be an integral part of the putter face 110 such as to be co-manufactured with the putter face 110. Alternatively, the ball striking face 112 may be an insert that is attached to the putter face 110. Each of the grooves 120 may extend from the toe end 180 to the heel end 190 to define a corresponding length 193 (only the length 193 of groove 144 is shown in FIG. 2). The lengths 193 of some or all of the grooves 120 may vary in a direction from the top rail 182 to the sole 192 so that each groove 120 may generally conform to the shape of the perimeter of the ball striking face 112. For example, the length of the grooves may increase from near the top rail 182 to a center 184 of the ball striking face 112 and decrease from the center 184 to near the sole 192. The center 184 may be a geometric center of the ball striking face 112. Alternatively, the center 184 may represent an inertial or weight related center of the ball striking face 112. However, the center 184 may be generally defined by a region of the ball striking face 112 that typically strikes the ball. As shown in FIG. 1, the length 193 of the grooves 120 may be similar. In other examples, such as the example shown in FIG. 2, the length 193 of the grooves may decrease from near the top rail 182 to the center 184 and decrease from near the sole 192 to the center 184. Thus, any groove length arranged on the ball striking face 112 is within the scope of the disclosure.
In another example shown in FIG. 3, a ball striking face 212 may include grooves 220 (shown specifically as grooves 222-244). The ball striking face 212 may be an integral part of the putter face 110 or a separate piece that is attached to the putter face 110. Accordingly, when describing the ball striking face 212, parts of the putter 100 and the putter head 102 are referred to with the same reference numbers described above.
FIG. 4 shows a schematic view of the groove 232 and FIG. 5 shows a horizontal cross section of the groove 232 taken at section line 5-5 of FIG. 3. The groove 232 is shown to be divided into horizontally spanning regions, generally shown as regions 271-275, which are visually defined in FIGS. 3 and 4 by vertical boundary lines. The horizontal regions 271-275 may define variations in the horizontal cross-sectional profile of the groove 232 from near the toe end 180 to near the heel end 190 and/or from near the top rail 182 to near the sole 192. Horizontal cross-sectional profile of a groove may refer to any property of the groove along the length 293 of the groove, such as length of a certain section of the groove, depth, width, cross-sectional shape, and/or construction materials. In the example of FIGS. 3-7, the grooves 220 include a first vertical wall 250 and a second vertical wall 252 that define the length 293 of the grooves 220. Each of the grooves 220 has a bottom surface 254 which defines a depth of the groove 220. The depth of each groove may vary from the first wall 250 to the second wall 252 according to the cross-sectional profile of the groove 220 in the regions 271-275. Each groove 220 also includes a first horizontal wall 256 and a second horizontal wall 258 that define the vertical boundaries of the groove 220. The distance between the first horizontal wall 256 and the second horizontal wall 258 defines a width 280 of the groove 220. The width 280 may vary from the first vertical wall 250 to the second vertical wall 252 as shown in the examples of FIGS. 38-45, where a groove may have a length 590, a first width 594, a second width 595 and/or a third width 596. In the example of FIGS. 3-7, however, the first horizontal wall 256 and the second horizontal wall 258 are generally parallel to define a generally constant width 280.
Referring to FIG. 5, the bottom surface 254 at the region 271 is downwardly sloped or curved to define a first depth 282 at the boundary between regions 271 and 272. The bottom surface 254 in the region 272 transitions with a steeper downward curve from the first depth 282 to a second depth 284 at the boundary between regions 272 and 273. If the bottom surface 254 is flat in the region 273, the second depth 284 may generally define the greatest depth of the groove 232. However, if the bottom surface 254 is not flat, the greatest depth of the groove 232 may be defined in another part of the region 273. Any of the grooves 220 may be symmetric about the vertical axis y. Accordingly, the shape of the groove 220 on each side of the y axis may mirror the shape of the groove 232 on the other side of the y axis. However, any of the grooves 220 may be asymmetric. The regions 271 and 275 define shallow portions of the groove 232 and the region 273 defines the deeper center portion of the groove 232. The deepest part of any of the grooves 220 may be at the center of the groove 220. The regions 272 and 274 facilitate transition of the bottom surface 254 from the depth 282 to the depth 284.
Referring to FIGS. 3 and 5, the general cross-sectional profile of each of the grooves 220 may remain generally similar from the top rail 182 to the sole 190. However, the cross-sectional profile including lengths, widths and/or depths of the regions 271-275 of each of the grooves 220 may progressively vary from the top rail 182 to the sole 192. In FIGS. 6 and 7, the horizontal cross sections of the grooves 238 and 244, respectively, are shown. For example, the regions 271-275 of the groove 238 are smaller in length than the regions 271-275 of the groove 232, respectively. Similarly, the regions 271-275 of the groove 244 are smaller in length than the regions 271-275 of the groove 238, respectively. In another example, the regions 271-275 of the groove 238 may have smaller depths than the regions 271-275 of the groove 232, respectively. Similarly, the regions 271-275 of the groove 244 may have smaller depths than the regions 271-275 of the groove 238, respectively.
The progressive increase in the length, depth and/or width of the regions 271-275 of the grooves 222-232 from the top rail 182 to generally the center of the ball striking face 212 and/or the decrease in the size of the regions 271-275 of the grooves 232-244 from generally the center of the ball striking face 212 to the sole 192 forms a central strike zone 260 (shown in FIG. 3), which may resemble the shape of a golf ball when viewed by an individual in an address position. The approximate visual representation of a golf ball can assist an individual with lining up the ball striking face 212 with the ball. The regions 273, which define the deepest parts of the grooves 220 may be larger in length at the center of the ball striking face 212 and progressively reduce in length toward the top rail 182 and the sole 192. Similarly, the transition regions 272 and 274 may have the greatest length at the center of the ball striking face 212 and progressively reduce in length toward the top rail 182 and the sole 192. Although the lengths of the regions 271-275 may vary depending on the location of the grooves 220 on the ball striking face 212, the depth of similar regions for each groove 220 may be similar or different. For example, the greatest depth of the groove 232 may be similar to the greatest depth of the groove 244. Alternatively, the depth of the grooves 222-244 may vary based on the location of the groove 220 relative to ball striking face 212. Alternatively yet, the depths of the grooves 222-244 may vary in any manner from the top rail 182 to the sole. Although the above examples may describe a particular number of horizontal regions, the apparatus, methods, and articles of manufacture described herein may include more or less horizontal regions.
In another example shown in FIG. 8, a ball striking face 312 includes grooves 320 (shown specifically as grooves 322-344). The ball striking face 312 may be an integral part of the putter face 110 or a separate piece that is attached to the putter face 110. Accordingly, when describing the ball striking face 312, parts of the putter 100 and the putter head 102 are referred to with the same reference numbers described above.
FIG. 9 shows a schematic view of the groove 332 and FIG. 10 shows a horizontal cross section of the groove 332 taken at section line 10-10 of FIG. 8. The groove 332 is shown to be divided into horizontally spanning regions 371-375, which are visually defined in FIGS. 8 and 9 by vertical boundary lines. The horizontal regions 371-375 may define variations in the horizontal cross-sectional profile of the groove 332 from near the toe end 180 to near the heel end 190 and/or from near the top rail 182 to near the sole 192. Horizontal cross-sectional profile of a groove may refer to any property of the groove along the length 393 of the groove, such as length of a certain section of the groove, depth, width, cross-sectional shape, and/or construction materials. In the example of FIGS. 8-12, the grooves 320 include a first vertical wall 350 and a second vertical wall 352 that define the length 393 of the grooves 320. Each of the grooves 320 has a bottom surface 354 which defines a depth of the groove 320. The depth of each groove may vary from the first wall 350 to the second wall 352 according to the cross-sectional profile of the groove 320 in the regions 371-375. Each groove 320 also includes a first horizontal wall 356 and a second horizontal wall 358 that define the vertical boundaries of the groove 320. The distance between the first horizontal wall 356 and the second horizontal wall 358 defines a width 380 of the groove 320. The width 380 may vary from the first vertical wall 350 to the second vertical wall 352 as shown in the examples of FIGS. 38-45. In the example of FIGS. 8-12, however, the first horizontal wall 256 and the second horizontal wall 258 are generally parallel to define a generally constant width 380.
Referring to FIG. 10, the bottom surface 354 at the region 371 may be generally flat and/or slightly sloped to define a first depth 382 at the boundary between 371 and 372. The bottom surface 354 in the region 372 transitions with a step downward from the first depth 382 to a second depth 384 at the boundary between the regions 372 and 373. The bottom surface 354 in the region 372 may be generally flat and/or slightly sloped such that the groove 320 has a generally uniform depth 384 in the region 372. The bottom surface 354 in the region 372 transitions with a step downward from the second depth 384 to a third depth 386. The bottom surface 354 in the region 373 may be generally flat or slightly sloped such that the groove 320 has a generally uniform depth 386 in the region 373. Any of the grooves 320 may be symmetric about the vertical axis y. Accordingly, the shape of the groove 320 on each side of the y axis mirrors the shape of the groove 320 on the other side of the y axis. However, any of the grooves 320 may be asymmetric. The depth 386 represents the greatest depth of the grooves 320.
Referring to FIGS. 10-12, the general cross-sectional profile of the grooves 320 may remain generally similar from the top rail 182 to the sole 190. However, the cross-sectional profile including the lengths, widths and/or the depths of the regions 371-375 of each of the grooves 320 may progressively vary from the top rail 182 to the sole 192. In FIGS. 11 and 12, the horizontal cross sections of the grooves 338 and 344, respectively, are shown. For example, the regions 371-375 of the groove 338 are smaller in length than the regions 371-375 of the groove 332, respectively. Similarly, the regions 371-375 of the groove 344 are smaller in length than the regions 371-375 of the groove 338, respectively. In another example, the regions 371-375 of the groove 338 may have smaller depths than the regions 371-375 of the groove 332, respectively. Similarly, the regions 371-275 of the groove 344 may have smaller depths than the regions 371-375 of the groove 338, respectively.
The progressive increase in the length, depth and/or width of the regions 371-375 of the grooves 322-332 from the top rail 182 to the center of the ball striking face 312 and/or the decrease in the size of the regions 371-375 of the grooves 332-344 form the center of the ball striking face 312 to the sole 192 forms a central strike zone 360 (shown in FIG. 8), which may discretely resemble the shape of a golf ball when viewed by an individual in an address position. The approximate visual representation of a golf ball can assist an individual with lining up the ball striking face 312 with the ball. The regions 373, which define the deepest parts of the grooves 360 may be larger in length at the center of the ball striking face 312 and progressively reduce in length toward the top rail 182 and the sole 192. Similarly, the transition regions 372 and 374 may have the greatest length at the center of the ball striking face 312 and progressively reduce in length toward the top rail 182 and the sole 192. Although the lengths of the regions 371-375 vary depending on the location of the grooves 320 on the ball striking face 312, the depth of similar regions for each groove 320 may be similar or different. For example, the greatest depth of the groove 344 may be similar to the greatest depth of the groove 332. Alternatively, the depth of the grooves 322-344 may vary based on the location of grooves 320 on the ball striking face 312. Alternatively yet, the depths of the grooves 322-344 may vary in any manner from the top rail 182 to the sole. Although the above examples may describe a particular number of horizontal regions, the apparatus, methods, and articles of manufacture described herein may include more or less horizontal regions.
In another example shown in FIG. 13, a ball striking face 412 includes grooves 420 (shown specifically as grooves 422-444). The ball striking face 412 may be an integral part of the putter face 110 or a separate piece that is attached to the putter face 110. Accordingly, when describing the ball striking face 412, parts of the putter 100 and the putter head 102 are referred to with the same reference numbers described above.
FIG. 14 shows a schematic view of the groove 432 and FIG. 15 shows a horizontal cross section of the groove 432 taken at section line 15-15 of FIG. 13. The groove 432 is shown to be divided into horizontally spanning regions 471 and 472, which are visually defined in FIGS. 13 and 14 by the boundary lines of the groove 432 and a vertical line at the center of the groove 432. The horizontal regions 471 and 472 may define variations in the horizontal cross-sectional profiles of the groove 432 from near the toe end 180 to near the heel end 190 and/or from near the top rail 182 to near the sole 192. Horizontal cross-sectional profile of a groove refers to any property of the groove along the length 493 of the groove, such as length of a certain section of the groove, depth, width, cross-sectional shape, and/or construction materials. In the example of FIGS. 13-17, the grooves 420 include a first vertical wall 450 and a second vertical wall 452 that define the length 493 of the grooves 420. Each of the grooves 420 has a bottom surface 454 which defines a depth of the groove 420. The depth of each groove may vary from the first wall 450 to the second wall 452 according to the cross-sectional profile of the groove 420 in the regions 471 and 472. Each groove 420 also includes a first horizontal wall 456 and a second horizontal wall 458 that define the vertical boundaries of the groove 420. The distance between the first horizontal wall 456 and the second horizontal wall 458 defines a width 480 of the groove 420. The width 480 may vary from the first vertical wall 450 to the second vertical wall 452 as shown in the examples of FIGS. 38-45. In the example of FIGS. 13-17, however, the first horizontal wall 456 and the second horizontal wall 458 are generally parallel to define a generally constant width 480.
Referring to FIG. 15, the bottom surface 454 at the region 471 has a linear profile and is downwardly sloped. The grooves 450 are symmetric about the center vertical axis y. Accordingly, the bottom surface 454 at the region 472 has a similar linear profile and is similarly downwardly sloped as the bottom surface 454 at the region 471. Accordingly, the depth of the grooves 420 gradually increase from a depth 482 at the first wall 452 and second wall 454 to a depth 484 at the center of the grooves 420. The depth 484 represents the deepest part of the grooves 420, which may be at the center of the groove 420.
Referring to FIGS. 15-17, the general cross-sectional profile of the grooves 420 may remain generally similar from the top rail 182 to the sole 190. However, the cross-sectional profile including the lengths and/or the depths of the regions 471 and 472 of each of the grooves 420 may progressively vary from the top rail 182 to the sole 192. For example, the regions 471 and 472 of the groove 438 are smaller in length than the regions 471 and 472 of the groove 332, respectively. Similarly, the regions 471 and 471 of the groove 444 are smaller in length than the regions 471 and 472 of the groove 438, respectively. In another example, the regions 471 and 472 of the groove 438 may have smaller depths than the regions 471 and 472 of the groove 432, respectively. Similarly, the regions 471 and 472 of the groove 444 may have smaller depths than the regions 471 and 472 of the groove 438, respectively.
The progressive increase in the length, depth and/or width of the regions 471 and 472 of the grooves 422-432 from the top rail 182 to the center of the ball striking face 412 and/or the decrease in the size of the regions 471 and 472 of the grooves 432-444 form the center of the ball striking face 412 to the sole 192 forms a central strike zone 460 (shown in FIG. 13). The regions 471 and 472 may have the greatest length at the center of the ball striking face 412 and progressively reduce in length toward the top rail 182 and the sole 192. Although the lengths of the regions 471 and 472 vary depending on the location of the grooves 420 on the ball striking face 412, the depth of similar regions for each groove 420 may be similar or different. For example, the greatest depth of the groove 444 may be similar to the greatest depth of the groove 432. Alternatively, the depth of the grooves 422-444 may vary based on the location of grooves 420 on the ball striking face 412. Alternatively yet, the depths of the grooves 422-444 may vary in any manner from the top rail 182 to the sole. Although the above examples may describe a particular number of horizontal regions, the apparatus, methods, and articles of manufacture described herein may include more or less horizontal regions.
In another example shown in FIG. 18, a ball striking face 512 includes grooves 520 (shown specifically as grooves 522-544). The ball striking face 512 may be an integral part of the putter face 110 or a separate piece that is attached to the putter face 110. Accordingly, when describing the ball striking face 512, parts of the putter 100 and the putter head 102 are referred to with the same reference numbers described above.
FIG. 19 shows a schematic view of the groove 532 and FIG. 20 shows a horizontal cross section of the groove 532 taken at section line 20-20 of FIG. 18. The groove 532 is shown to be divided into horizontally spanning regions 571 and 572, which are visually defined in FIGS. 18 and 19 by the boundary lines of the groove 532 and a vertical line at the center of the groove 532. The horizontal regions 571 and 572 may define variations in the horizontal cross-sectional profiles of the groove 532 from near the toe end 180 to near the heel end 190 and/or from near the top rail 182 to near the sole 192. Horizontal cross-sectional profile of a groove refers to any property of the groove along the length 593 of the groove, such as a length of a certain section of the groove, depth, width, cross-sectional shape, and/or construction materials. In the example of FIGS. 18-22, the grooves 520 include a first vertical wall 550 and a second vertical wall 552 that define the length 593 of the grooves 520. Each of the grooves 520 has a bottom surface 554 which defines a depth of the groove 520. The depth of each groove may vary from the first wall 550 to the second wall 552 according to the cross-sectional profile of the groove 520 in the regions 571 and 572. Each groove 520 also includes a first horizontal wall 556 and a second horizontal wall 558 that define the vertical boundaries of the groove 520. The distance between the first horizontal wall 556 and the second horizontal wall 558 defines a width 580 of the groove 520. The width 580 may vary from the first vertical wall 550 to the second vertical wall 552 as shown in the examples of FIGS. 38-45. In the example of FIGS. 18-22, however, the first horizontal wall 556 and the second horizontal wall 558 are generally parallel to define a generally constant width 580.
Referring to FIG. 20, the bottom surface 554 at the region 571 has a linear profile and is downwardly sloped. The bottom surface 554 in the region 572 also has a linear profile and is downwardly sloped. However, because the second wall 552 is longer than the first wall 550, the bottom surface 554 in the region 572 has a smaller slope than the bottom surface 554 in the region 571. Accordingly, the grooves 550 of this example are asymmetric about the vertical center axis y. Thus, the grooves 250 have a first depth 582 defined by the first wall 550, a second depth 584 defined by the second wall 552 and a center depth 586, which is gradually reached from the depths 582 and 584 according to the downwardly sloped bottom surface 554 of the regions 571 and 572, respectively. The center depth 586 may be the depth of the deepest part of the groove 520.
Referring to FIGS. 20-22, the general cross-sectional profile of the grooves 520 may remain generally similar from the top rail 182 to the sole 190. However, the cross sectional profile including the lengths, widths and/or the depths of the regions 571 and 572 of each of the grooves 520 may progressively vary from the top rail 182 to the sole 192. In FIGS. 21 and 22, the horizontal cross sections of the grooves 538 and 544, respectively, are shown. For example, the regions 571 and 572 of the groove 538 are smaller in length than the regions 571 and 572 of the groove 532, respectively. Similarly, the regions 571 and 572 of the groove 544 are smaller in length than the regions 571 and 572 of the groove 538, respectively. In another example, the regions 571 and 572 of the groove 538 may have smaller depths than the regions 571 and 572 of the groove 532, respectively. Similarly, the regions 571 and 572 of the groove 544 may have smaller depths than the regions 571 and 572 of the groove 538, respectively.
The progressive increase in the length, depth and/or width of the regions 571 and 572 of the grooves 522-532 from the top rail 182 to the center of the ball striking face 512 and/or the decrease in the size of the regions 571 and 572 of the grooves 532-544 form the center of the ball striking face 512 to the sole 192 forms a central strike zone 560 (shown in FIG. 18). The regions 571 and 572 may have the greatest length at the center of the ball striking face 512 and progressively reduce in length toward the top rail 182 and the sole 192. Although the lengths of the regions 571 and 572 vary depending on the location of the grooves 520 on the ball striking face 512, the depth of similar regions for each groove 520 may be similar or different. For example, the greatest depth of the groove 544 may be similar to the greatest depth of the groove 532. Alternatively, the depth of the grooves 522-544 may vary based on the location of grooves 520 on the ball striking face 512. Alternatively yet, the depths of the grooves 522-544 may vary in any manner from the top rail 182 to the sole. Although the above examples may describe a particular number of horizontal regions, the apparatus, methods, and articles of manufacture described herein may include more or less horizontal regions.
The grooves 220, 320, 420 and 520 described above illustrate four examples of horizontal cross-sectional profile of grooves for use with the putter 100. Other examples of horizontal cross sectional profiles are shown in FIGS. 29-37, where each groove may have a length 590, a first depth 591, a second depth 592 and/or a third depth 593. A groove may be defined by any number of horizontal regions, where any one or more regions have similar properties or dissimilar properties. A groove that may be symmetric or asymmetric about the y axis, for example, may have a bottom surface with a complex combination of linear and nonlinear shapes defining similar or various depths from the toe end 180 to the heel end 190. Such a groove may be described with a large number of horizontal regions, where each region defines one or more of the noted complex shapes. Accordingly, the number, arrangement, sizes and the other properties of the horizontal ranges described above are in no way limiting to the groove cross-sectional profiles according to the disclosure.
In the above examples, the grooves on each corresponding ball striking face have similar shapes. However, the grooves on ball striking face may have dissimilar shapes. For example, a ball striking face may include a combination of grooves 220 and 320. In another example, the ball striking face may include a combination of grooves 420 and 520. Thus, any combination of groove cross-sectional profiles may be used on a ball striking face to impart a particular ball striking property to the putter.
The horizontal cross-sectional profiles of the grooves may progressively and proportionally vary from the top rail 182 to the center of the ball striking face and may progressively vary from the center of the ball striking face to the sole 192. The noted progressive variation may define a ball strike zone that is larger at the center of the ball striking face than near the top rail 182 and the sole 192. Furthermore, the progressive noted variation of the grooves' horizontal cross-sectional profiles provides grooves at the center of the ball striking face and around the center of the ball striking face that have longer deep groove sections than grooves near the top rail 182 and the sole 192. However, the above-described progressive variation of the grooves is exemplary and other progressive variation schemes may be used to impart particular ball striking properties to various portions of the ball striking face.
Referring to FIG. 23, a ball striking face 612 according to another example is shown having grooves 620. FIGS. 24-26 show a vertical cross-sectional shape of the grooves 620 as viewed from section line 24-24 of FIG. 23. In FIG. 24, the vertical cross-sectional shape of the groove 620 is box-shaped, rectangular or square. In FIG. 25, the vertical cross-sectional shape of the groove 620 is V-shaped. In FIG. 26, the vertical cross-sectional shape of the groove 620 is U-shaped. The vertical cross-sectional groove shapes of FIGS. 24-26 are applicable to any groove according to the disclosure. For example, the vertical cross-sectional shape of the grooves 220 may be rectangular or square according to the grooves 620 of FIG. 24. In another example, the vertical cross-sectional shape of the grooves 620 may be V-shaped according to the groove 620 of FIG. 25. Furthermore, the vertical cross-sectional shape of a groove may vary from the toe end 180 to the heel end 190. For example, with reference to FIGS. 4 and 5, a groove 220 may be have a square or rectangular vertical cross-sectional shape in regions 271 and 275, U-shaped vertical cross-sectional shape in regions 271 and 274, and V-shaped vertical cross-sectional shape in region 273. Additionally, the vertical cross-sectional shapes of the grooves may also vary from the top rail 182 to the sole 190. For example, grooves near the top rail 182 and the sole 192 may have a square vertical cross-sectional shape, while the grooves at the center of the club face may have a U-shaped vertical cross-sectional shape.
The ball striking face of the putter in the above examples is shown to have grooves from the top rail 182 to the sole 192. However, a ball striking face may have more or less grooves, or have sections that are without grooves. For example, a ball striking face may have several grooves at the center section of the ball strike face and be without grooves at sections near the top rail 182 or the sole 192.
The grooves are not limited to extending horizontally across the ball striking face. The ball striking face may have vertical grooves that vary in depth as described above or a combination of vertical and horizontal grooves with varying horizontal and/or vertical cross-sectional profiles. The orientation of the grooves may be such that a matrix-like ball striking face is provided on the putter.
Referring to FIG. 27, a ball striking face 712 having grooves 720 may be horizontally separated into three portions, which are the toe portion 780, a center portion 785 and a heel portion 790. The ball striking face 712 may be similar to the ball striking face 212 and 312 described above. Accordingly the grooves 720 have regions 271-275 and 371-375 similar to grooves 220 and 320, respectively, described above. The three portions described above horizontally separate the ball striking face 712 and span vertically from the top rail 182 to the sole 192. The toe portion 780 is near the toe end 180, the heel portion 790 is near the heel end 190, and the center portion 785 is between the toe portion 780 and the heel portion 790. According to various examples, the depth of the grooves 720 at the toe portion 780 and the heel portion 790 may not be greater than the depth of the grooves 720 at the center portion 785. In one example, the shallowest depth of the grooves 720, which may be nearest to the toe end 180 or nearest to the heel end 190, may be approximately 0.003 inch. At or near the center portion 785, the depth of the grooves 720 may increase as described above to a depth of approximately 0.017 inch. The variable depth may include a portion with a depth of at least 0.020 inches but less than 0.022 inches. The variable width may include a portion with a width of at least 0.035 inches but less than 0.037 inches.
Referring to FIG. 28, the ball striking face 712 may be vertically separated into three portions, which are the top rail portion 782, the mid portion 786 and the sole portion 792. These portions vertically separate the ball striking face 712 and span horizontally from the toe end 180 to the heel end 190. The top rail portion 782 is near the top rail 182, the sole portion 792 is near the sole 192, and the mid portion 786 is between the top rail portion 782 and the sole portion 792. The length of the deepest portion of a groove 720 may vary from the top rail portion 782 to the mid portion 786 and from the mid portion 786 to the sole portion 792. For example, with respect to the examples described above, the length of the deepest portion of a groove may refer to the groove 720 that is proximately centrally located between the top rail portion 782 and the sole portion 792. As shown in FIGS. 27 and 28, the length of the grooves 710 may be greatest at the mid portion 786 and gradually reduce toward the top rail portion 782 and toward the sole portion 792.
FIGS. 29-37 show examples of different groove horizontal cross-sectional profiles according to the disclosure. In the above examples, the width of the grooves 220, 320, 420 and 520 is shown to have a rectangular profile. However, a groove according to the disclosure may have different width profiles as shown by the examples of FIGS. 38-45. Accordingly, a groove according to the disclosure may have any horizontal cross-sectional profile, vertical cross-sectional profile, width profile and/or depth profile.
A cross-sectional profile of a groove including variations in lengths, depth, width and/or cross-sectional shape of the groove may affect ball speed, control, and/or spin. The disclosed variable depth grooves may improve the consistency of the ball speed after being struck by the putter face by about 50% over a plastic putter face insert, and by about 40% over a non-grooved aluminum putter face insert. Striking a ball with a putter having grooves according to the disclosure: (1) may result in lower ball speeds, which may result in decreased ball roll out distance; (2) may result in heel and toe shots to have decreased ball speeds compared to center hits, and also may result in shorter ball roll out distance; (3) allow relatively lower and higher handicap players to strike the ball with different locations on the putter face (higher handicap players tend to hit lower on the ball striking face whereas lower handicap player tend to hit higher on the ball striking face. Also, relatively higher handicap players may have a wider range of hit locations whereas relatively lower handicap players may have a closer range of hit locations; and/or (4) a putter face with grooves in the center of the face may result in reduced ball speed/roll out distance for center shots, which may result in a more consistent ball speed/roll out distances for center/heel/toe shots.
Referring to FIG. 46, another example of a putter face 810 having grooves of variable cross-sectional profiles is shown. The putter face 810 is shown to have fourteen grooves, which are grouped into grooves 822-828 near the toe end 180, grooves 830-840 at the center of the putter face 810, and grooves 842-848 near the heel end 190. In this example, the more prominent grooves are located at the center of the putter face 810, and less prominent grooves are on the periphery of the center. A more prominent groove may refer to a groove that has a greater depth and/or width as compared to a less prominent groove. As shown in FIG. 46, the grooves 832-838 may be more prominent that the remaining grooves on the putter face 810. Furthermore, portions of the putter face 810 may be without grooves. These portions are referred to with reference number 850.
Referring to FIG. 47, another example of a putter face 910 having grooves of variable cross-sectional profile is shown. The putter face 910 is shown to have ten grooves 922-940. The length of each groove progressively increases from the top rail 182 to the sole 190. Each of the grooves 922-940 or groups of the grooves 922-940 may have different vertical cross-sectional shapes. For example, grooves 922-930 are shown to have box-shaped vertical cross sections, while grooves 932-940 are shown to have V-shaped vertical cross sections.
Referring to FIG. 48, a horizontal cross section of a groove 922 according to another embodiment is shown. A bottom surface 954 of the groove 922 is shown to gradually recede from the edges 950 and 952 of the groove to a greatest depth 951 of the groove 922. Any of the grooves according to the disclosure may have the same horizontal cross-sectional shape as the groove 922. Any of the grooves according to the disclosure may have the same depth 951. However, the depth 951 may be proportionally reduced as the length of the groove is reduced.
In another example shown in FIG. 49, a ball striking face 1012 may include grooves 1220 (shown specifically as grooves 1222-1256). The ball striking face 1012 may be for use with the putter 100. Accordingly, parts of the putter 100 and the putter head 102 are referred to with the same reference numbers presented above. The grooves may have any cross sectional shape, length and width according to the disclosure.
Referring to FIG. 49, a side cross-sectional view of a ball striking face 1012 having grooves 1220 according to another example is shown. The ball striking face 1012 may be separated into two portions with respect to the grooves 1220. The ball striking face 1012 may include a top rail portion 1282 and the sole portion 1286. The top rail portion 1282 and the sole portion 1286 may vertically separate the ball striking face 1012 and span horizontally from the toe end 180 to the heel end 190. The top rail portion 1282 may extend generally from a center portion of the ball striking face 1012, which is represented by the center line 1284, to near the top rail 182 and include the grooves 1222. The sole portion 1286 may extend generally from near the sole 192 to the center portion 1284 and include the grooves 1224. The grooves 1224 of the sole portion 1286 may have a greater depth at one or more locations along each groove 1224 than the grooves 1222 of the top rail portion 1282. By having shallower grooves 1222 at the top rail portion 1282, the speed by which a golf ball rolls forward after being struck by the putter may increase so as to provide a more consistent and smooth ball roll out. Alternatively, the depth of the grooves 1220 may progressively reduce in one or more groove steps from the center portion 1284 to the top rail 182 (not shown). In another example, the depth of pairs of grooves may progressively reduce from the center portion 1284 to the top rail 182 (not shown). Accordingly, the reduction in groove depth from the sole 192 to the top rail 182 may be for each groove, for pairs of grooves or for various groupings of the grooves.
Referring to FIG. 50, the grooves 1224 of the sole portion 1286 may have a smaller depth at one or more locations along each groove 1224 than the grooves 1222 of the top rail portion 1282. Alternatively, the depth of the grooves 1220 may progressively increase in one or more groove steps from the center portion 1284 and/or the sole 192 to the top rail 182 (not shown). In another example, the depth of pairs of grooves may progressively increase from the center portion 1284 and/or the sole 192 to the top rail 182 (not shown). Accordingly, the increase in groove depth from the center portion 1284 and/or the sole 192 to the top rail 182 may be for each groove, for pairs of grooves or for various groupings of the grooves.
FIGS. 51 and 52 show other examples according to the disclosure. Referring to FIG. 51, a putter head 1300 includes a ball striking face 1312, which has a plurality of horizontal grooves 1320 and vertical grooves 1322. Each of the grooves 1320 and 1322 may have a different configuration as compared to another groove, such as variable cross-sectional profiles, depth profiles, width profiles, length profiles and/or other groove characteristics from the toe end 1380 to near the heel end 1390 and/or from a top rail 1382 to a sole 1392. For example, the depth of the horizontal grooves 1320 may progressively increase in one or more groove steps from the top rail 1382 to the sole 1386. The apparatus, methods, and articles of manufacture described herein are not limited in this regard.
Referring to FIG. 52, a putter head 1400 includes a ball striking face 1412, which has a plurality of first diagonal grooves 1420 and second diagonal grooves 1422. The first diagonal grooves 1420 may be generally parallel to each other. Similarly, the second diagonal grooves 1422 may be generally parallel to each other. The first diagonal grooves 1420 and the second diagonal grooves 1422 may be transverse to each other as shown in FIG. 52. For example, the first diagonal grooves 1420 may intersect the second diagonal grooves 1422 at an angle of 30°, 45°, 60° or 90°. Each of the grooves 1420 and 1422 may have a different configuration as compared to another groove, such as variable cross-sectional profiles, depth profiles, width profiles, length profiles and/or other groove characteristics from the toe end 1480 to near the heel end 1490 and/or from a top rail 1482 to a sole 1492. For example, the depth of the first diagonal grooves 1420 may progressively increase in one or more groove steps from the top rail 1482 to the sole 1486. The apparatus, methods, and articles of manufacture described herein are not limited in this regard.
Referring to FIG. 52, a process 2000 of manufacturing a golf club head according to one example is shown. The process 2000 includes forming a golf club face (block 2002) defined by a toe end, a heel end, a top rail and a sole. A golf club face may be formed with a golf club head so that the golf club head and the golf club face are a one-piece continuous part. Alternatively, the golf club head and the golf club face may be formed separately. The golf club face may then be attached to the golf club face by using adhesive, tape, welding, soldering, fasteners and/or other suitable methods and devices. The golf club head and/or the golf club face may be manufactured from any material. For example, the golf club head and/or the golf club face may be made from titanium, titanium alloy, other titanium-based materials, steel, aluminum, aluminum alloy, other metals, metal alloys, plastic, wood, composite materials, or other suitable types of materials. The golf club head and/or the golf club face may be formed using various processes such as stamping (i.e., punching using a machine press or a stamping press, blanking, embossing, bending, flanging, or coining, casting), injection molding, forging, machining or a combination thereof, other processes used for manufacturing metal, plastic and/or composite parts, and/or other suitable processes. In one example, when manufacturing a putter head, the material of the putter face and/or the ball striking face may be determined so as to impart a certain ball strike and rolling characteristics to the putter face. In another example, when the ball striking face 212 is separate from the putter face 110 and is inserted and attached into a correspondingly shaped depression on the putter face 110, the striking face 212 may be constructed from a lighter material than the putter face 110 to generally reduce the overall weight of the putter.
According to the process 2000, grooves are formed on the club face and/or club head between the top rail and the sole such that each groove extends between the toe end and the heel end and depths of the grooves vary in a direction extending between the top rail and the sole and in a direction extending between the heel end and the toe end (block 2004). The grooves may be formed using various processes such as casting, forging, machining, spin milled, and/or other suitable processes. The vertical cross-sectional shape of a groove may depend on the method by which a groove is manufactured. For example, the type of cutting bit when machining a groove may determine the vertical cross-sectional shape of the groove. The vertical cross sectional shape of a groove may be symmetric, such as the examples described above, or may be asymmetric (not shown). In one example, the width of a groove can be 0.032 inch, which may be the width of the cutting bit. Accordingly, when machining a groove, the shape and dimensions of the cutting bit may determine the shape and dimension of the groove.
The grooves may be manufactured by spin milling the ball strike face, or stamping or forging the grooves into the ball striking face. The grooves may also be manufactured direction on the putter head to create a ball striking face as described above directly on the putter head. A groove may be manufactured by press forming the groove on the putter head. For example, a press can deform and/or displace material on the putter head to create the groove. A groove may be manufacturing by a milling process where the rotating axis of the milling tool is normal to putter face. The rotating axis of the milling tool may be oriented at an angle other than normal to the putter face. A groove may be manufactured by overlaying one material that is cut clean through to form a through groove onto a base or solid material. A groove may be manufactured by laser and/or thermal etching or eroding of the putter face material. A groove may be manufactured by chemically eroding the putter face material using photo masks. A groove may be manufactured by electro/chemically eroding the putter face material using a chemical mask such as wax or a petrochemical substance. A groove may be manufactured by abrading the face material using air or water as the carry medium of the abrasion material such as sand. Any one or a combination of the methods discussed above can be used to manufacture one or more of the grooves on the putter head. Furthermore, other methods used to create depressions in any material may be used to manufacture the grooves.
Referring to FIG. 54, a ball striking face 2212 according to another example is shown. The ball striking face 2212 may be vertically separated into and defined by three portions, which are the top rail portion 2282, the mid portion 2286 and the sole portion 2292. The top rail portion 2282, the mid portion 2286 and the sole portion 2292 vertically separate the ball striking face 2212 and span horizontally from the toe end 180 to the heel end 190. The top rail portion 2282 is near the top rail 182, the sole portion 2292 is near the sole 192, and the mid portion 2286 is between the top rail portion 2282 and the sole portion 2292. In FIG. 54, the ball striking face 2212 may have twelve grooves 2222-2244, which may be collectively referred to as the grooves 2220. For example, grooves 2222, 2224, 2226 and 2228 may be considered to be in the top rail portion 2282; grooves 2230, 2232, 2234 and 2236 may be considered to be in the mid portion 2286; and grooves 2238, 2240, 2242 and 2244 may be considered to be in the sole portion 2292. However, one or more of the grooves 2220 may be considered to be in two adjacent portions of the three vertically separated portions, i.e., part of a groove 2220 overlaps and adjacent portion. The length of the grooves 2220 may be greatest at the mid portion 2286 and gradually reduce toward the top rail portion 2282 and toward the sole portion 2292. Alternatively, the length of the grooves 2220 may vary according to the peripheral profile of the ball striking face 2212. The top rail portion 2282, the mid portion 2286 and the sole portion 2292 are exemplary and may define portions on the ball striking face 2212 where the grooves 2220 that may be located in such portions have one or more similar configurations or characteristics. Accordingly, the ball striking face 2212 may be defined by various vertical and/or horizontal portions associated with one or more groove configurations or characteristics. The apparatus, methods, and articles of manufacture described herein are not limited in this regard.
FIG. 55 shows a horizontal cross section of the ball striking face 2212 taken at the groove 2234. Each groove 2220 may include a center portion 2254 having a bottom surface 2255, which may define a greatest depth 2257 of the groove 2220. The center portion 2254 has a length 2259, which may vary depending on the location of the groove 2220 on the ball striking face 2212. In the example of FIG. 54, the center portions 2254 of the grooves 2220 of the mid portion 2286 have generally the same length. The apparatus, methods, and articles of manufacture described herein are not limited in this regard.
A center of the ball striking face 2212 may be defined by a y-axis 2261. The y-axis 2261 may also define a center axis of the center portion 2254 as shown in FIGS. 54 and 55. However, the center portion 2254 may be offset (not shown) relative to the y-axis 2261. According to the example of FIG. 55, each of the bottom surfaces 2255 of the grooves 2230, 2232, 2234 and 2236 extends substantially equally from the y-axis 2261 toward the toe end 180 and toward the heel end 190. As shown in FIG. 55, a distance between the y-axis 2261 and the heel edge portion 2264 of the center portion 2254 may be defined as a length 2262. The heel edge portion 2264 may be defined as a portion of a groove between the y-axis 2261 and the heel end 190 where the depth of the groove increases from the depth 2257 and transitions to the opening or the top of the groove. A distance between the y-axis 2261 and the toe edge portion 2268 of the center portion 2254 may be defined as a length 2266. The toe edge portion 2268 may be defined as a portion of a groove between the y-axis 2261 and the toe end 180 where the depth of the groove increases from the depth 2257 and transitions to the opening or the top of the groove. According to the example of FIGS. 54 and 55, the length 2262 is substantially the same as the length 2266. A putter having a ball striking face 2212 as shown in FIG. 54 may be suitable for an individual who has a straight putting stroke.
Referring to FIG. 56, a ball striking face 3212 according to another example is shown. The ball striking face 3212 may be vertically separated into and defined by three portions, which are the top rail portion 3282, the mid portion 3286 and the sole portion 3292. The top rail portion 3282, the mid portion 3286 and the sole portion 3292 vertically separate the ball striking face 3212 and span horizontally from the toe end 180 to the heel end 190. The top rail portion 3282 is near the top rail 182, the sole portion 3292 is near the sole 192, and the mid portion 3286 is between the top rail portion 3282 and the sole portion 3292. In FIG. 56, the ball striking face 3212 may have twelve grooves 3222-3244, which may be collectively referred to as the grooves 3220. For example, grooves 3222, 3224, 3226 and 3228 may be considered to be in the top rail portion 3282; grooves 3230, 3232, 3234 and 3236 may be considered to be in the mid portion 3286; and grooves 3238, 3240, 3242 and 3244 may be considered to be in the sole portion 3292. However, one or more of the grooves 3220 may be considered to be in two adjacent portions of the three vertically separated portions, i.e., part of a groove 3220 overlaps and adjacent portion. The length of the grooves 3220 may be greatest at the mid portion 3286 and gradually reduce toward the top rail portion 3282 and toward the sole portion 3292. Alternatively, the length of the grooves 3220 may vary according to the peripheral profile of the ball striking face 3212. The top rail portion 3282, the mid portion 3286 and the sole portion 3292 are exemplary and may define portions on the ball striking face 3212 where the grooves 3220 that may be located in such portions have one or more similar configurations or characteristics. Accordingly, the ball striking face 3212 may be defined by various vertical and/or horizontal portions associated with one or more groove configurations or characteristics. The apparatus, methods, and articles of manufacture described herein are not limited in this regard.
FIG. 57 shows a horizontal cross section of the ball striking face 3212 taken at the groove 3234. Each groove 3220 may include a center portion 3254 having a bottom surface 3255, which may define a greatest depth 3257 of the groove 3220. The center portion 3254 has a length 3259, which may vary depending on the location of the groove 3220 on the ball striking face 3212. In the example of FIG. 56, the center portions 3254 of the grooves 3220 of the mid portion 3286 have generally the same length. The apparatus, methods, and articles of manufacture described herein are not limited in this regard.
A center of the ball striking face 3212 may be defined by a y-axis 3261. The y-axis 3261 may also define a center axis of the center portion 3254 as shown in FIGS. 56 and 57. However, the center portion 3254 may be offset (not shown) relative to the y-axis 3261. According to the example of FIG. 57, each of the bottom surfaces 3255 of the grooves 3230, 3232, 3234 and 3236 extends toward the heel end 190 from the y-axis 3261 at a greater length than the bottom surface 2255 of the groove 2234 of FIG. 55. As shown in FIG. 57, a distance between the y-axis 3261 and the heel edge portion 3264 of the center portion 3254 may be defined as a length 3262. The heel edge portion 3264 may be defined as a portion of a groove between the y-axis 3261 and the heel end 190 where the depth of the groove increases from the depth 3257 and transitions to the opening or the top of the groove. A distance between the y-axis 3261 and the toe edge portion 3268 of the center portion 3254 may be defined as a length 3266. The toe edge portion 3268 may be defined as a portion of a groove between the y-axis 3261 and the toe end 180 where the depth of the groove increases from the depth 3257 and transitions to the opening or the top of the groove. According to the example of FIG. 57, the length 3262 is greater than the length 2266 of FIG. 55. The length 3262 may also be greater than the length 3266. Alternatively, the length 3262 may be substantially similar to the length 3266, but greater than the length 2266 of FIG. 55. Thus, the deepest portions of some or all of the grooves 3220 of the ball striking face 3212 of FIG. 56 extend more toward the heel end 190 than the deepest portions of the grooves 2220 of the ball striking face 2212 of FIG. 54. A putter having a ball striking face 3212 as shown in FIG. 56 may be suitable for an individual who has a slight arc putting stroke.
Referring to FIG. 58, a ball striking face 4212 according to another example is shown. The ball striking face 4212 may be vertically separated into and defined by three portions, which are the top rail portion 4282, the mid portion 4286 and the sole portion 4292. The top rail portion 4282, the mid portion 4286 and the sole portion 4292 vertically separate the ball striking face 4212 and span horizontally from the toe end 180 to the heel end 190. The top rail portion 4282 is near the top rail 182, the sole portion 4292 is near the sole 192, and the mid portion 4286 is between the top rail portion 4282 and the sole portion 4292. In FIG. 58, the ball striking face 4212 may have twelve grooves 4222-4244, which may be collectively referred to as the grooves 4220. For example, grooves 4222, 4224, 4226 and 4228 may be considered to be in the top rail portion 4282; grooves 4230, 4232, 4234 and 4236 may be considered to be in the mid portion 4286; and grooves 4238, 4240, 4242 and 4244 may be considered to be in the sole portion 4292. However, one or more of the grooves 4220 may be considered to be in two adjacent portions of the three vertically separated portions, i.e., part of a groove 4220 overlaps and adjacent portion The length of the grooves 4220 may be greatest at the mid portion 4286 and gradually reduce toward the top rail portion 4282 and toward the sole portion 4292. Alternatively, the length of the grooves 4220 may vary according to the peripheral profile of the ball striking face 4212. The top rail portion 4282, the mid portion 4286 and the sole portion 4292 are exemplary and may define portions on the ball striking face 4212 where the grooves 4220 that may be located in such portions have one or more similar configurations or characteristics. Accordingly, the ball striking face 4212 may be defined by various vertical and/or horizontal portions associated with one or more groove configurations or characteristics. The apparatus, methods, and articles of manufacture described herein are not limited in this regard.
FIG. 59 shows a horizontal cross section of the ball striking face 4212 taken at the groove 4232. Each groove 4220 may include a center portion 4254 having a bottom surface 4255, which may define a greatest depth 4257 of the groove 4220. The center portion 4254 has a length 4259, which may vary depending on the location of the groove 4220 on the ball striking face 4212. In the example of FIG. 58, the center portions 4254 of the grooves 4220 of the mid portion 4286 have generally the same length. The apparatus, methods, and articles of manufacture described herein are not limited in this regard.
A center of the ball striking face 4212 may be defined by a y-axis 4261. The y-axis 4261 may also define a center axis of the center portion 4254 as shown in FIGS. 58 and 59. However, the center portion 4254 may be offset (not shown) relative to the y-axis 4261. According to the example of FIG. 59, each of the bottom surfaces 4255 of the grooves 4230, 4232, 4234 and 4236 extends toward the heel end 190 from the y-axis 4261 at a greater length than the bottom surface 3255 of the groove 3234 of FIG. 57. As shown in FIG. 59, a distance between the y-axis 4261 and the heel edge portion 4264 of the center portion 4254 may be defined as a length 4262. The heel edge portion 4264 may be defined as a portion of a groove between the y-axis 4261 and the heel end 190 where the depth of the groove increases from the depth 4257 and transitions to the opening of the groove. A distance between the y-axis 4261 and the toe edge portion 4268 of the center portion 4254 may be defined as a length 4266. The toe edge portion 4268 may be defined as a portion of a groove between the y-axis 4261 and the toe end 180 where the depth of the groove increases from the depth 4257 and transitions to the opening of the groove. According to the example of FIG. 59, the length 4262 is greater than the length 3266 of FIG. 57, hence greater than the length 2266 of FIG. 55. The length 4262 may be greater than the length 4266. Alternatively, the length 4262 may be substantially similar to the length 4266, but greater than the length 3266 of FIG. 57. Thus, the deepest portions of some or all of the grooves 4220 of the ball striking face 4212 of FIG. 58 extend more toward the heel end 190 than the deepest portions of the grooves 3220 of the ball striking face 3212 of FIG. 56. A putter having a ball striking face 4212 as shown in FIG. 58 may be suitable for an individual who has a strong arc putting stroke.
According to the examples of FIGS. 54-59, grooves on a putter may be configured to optimize performance of an individual based on the individual's putting stroke. Depending on the degree of arc in an individual's putting stroke, any of the grooves described herein may be provided on a putter such that portions of some of all of the grooves that generally define the depth of the grooves extend from the center portion of the striking face of the putter to the toe end at a certain length to optimize the performance of an individual when using the putter. Thus, the length of the deepest part of a groove may be proportional to a degree of arc in an individual's putting stroke. For example, for an individual having a putting stroke that is between a strong arc putting stroke and a slight arc putting stroke, the portions of the grooves that generally define the depth of the grooves may extend from the y-axis toward the toe end 190 at a greater length than the grooves 3230, 3232, 3234 and 3236 of the ball striking first 3212, but less than the grooves 4230, 4232, 4034 and 4036 of the ball striking face 4212. In the examples of FIGS. 54-59, the portions of the grooves in the mid portion of the striking face that define the depth of the groove differ based on the putting stroke type of an individual. However, all of the grooves on the striking face including the grooves in the top rail portion and the sole portion may be configured according to the above examples based on the putting stroke type of an individual. Furthermore, the grooves according to the examples of FIGS. 54-59 may have any shape or configuration. For example, a ball striking face according to the examples of FIGS. 54-59 may have groove cross sectional shapes according to the groove examples of FIGS. 5-7, 10-12, 15-17 and/or 31-35. The apparatus, methods, and articles of manufacture described herein are not limited in this regard.
A golf club head, a ball striking face and/or grooves according to the examples of FIGS. 54-59 may be manufactured by any of the methods and/or with any of the materials described herein. Each groove may have a width of about 0.032 inches (0.081 cm) and have a depth of between about 0.003 inches (0.008 cm) to about 0.017 inches (0.043 cm). As described in detail herein, any of the ball striking faces 2212, 3212 or 4212 may be in the form of an insert that is to a golf club head or a correspondingly shaped recess in a golf club head. The insert may be flush with the remaining portions of the face of the golf club head, which may define a reference plane. Accordingly, the grooves of the ball striking face deviate into the golf club head or are below the reference plane. Alternatively, all or portions of the insert may protrude from the reference plane such that all or portions of the grooves are positioned above the reference plane. By having interchangeable ball striking faces for one or more golf clubs such putters, a ball striking face of a golf club head can be exchanged with another ball striking face so as to improve an individual's performance based on his or her putting style. For example, an individual whose putting style has changed over a certain period of time can exchange the ball striking face of his or her putter with another ball striking face according to the disclosure so that the putter is better adapted to the individual's current putting style. Instead of having interchangeable ball striking faces, any of the grooves described herein including the exemplary grooves of FIGS. 54-59 may be manufactured on the golf club head. The apparatus, methods, and articles of manufacture described herein are not limited in this regard.
In another example shown in FIG. 60, a ball striking face 5212 may include grooves 5220 (shown specifically as grooves 5222-5244). The ball striking face 5212 may be an integral part of the putter face 110 or a separate part that is attached to the putter face 110. Accordingly, when describing the ball striking face 5212, parts of the putter 100 and the putter head 102 are referred to with the same reference numbers described above. Similar to the other examples described herein, the depth, length and/or width of each groove 5220 may increase, decrease and/or vary from the toe end 180 to the heel end 190 and/or from a top rail 182 to a sole 192 of the putter head 102. The apparatus, methods, and articles of manufacture described herein are not limited in this regard.
FIG. 61 shows a schematic top view of the groove 5232 and FIG. 62 shows a horizontal cross section of the groove 5232 to illustrate the configuration of the grooves 5220 as described below. Each of the grooves 5220 includes a first horizontal wall 5256 and a second horizontal wall 5258 that define the vertical boundaries of the grooves. Each groove 5220 may also include a first end wall 5250 and a second end wall 5252. Each of the grooves 5220 has a bottom surface 5254 which defines a depth 5255 of the groove 5220. The depth 5255 of each groove 5220 may vary from the first wall 5250 to the second wall 5252. The grooves 5220 may not have any end walls as the depth of each groove 5220 may gradually diminish until the bottom surface 5254 meets the ball striking face 5212. The distance between the first horizontal wall 5256 and the second horizontal wall 5258 at any location along the groove defines a width 5280 of the groove 5220 at that location. The distance between the first end wall 5250 and the second end wall 5252 defines a length 5293 of the grooves 5220.
The variation in the depth 5255 of each groove 5220 relative to the variation in the width 5280 of each groove 5220 may depend on the cutting tool that is used to manufacture the groove 5220. According to one example, the variation in the width of the groove may be similar to the variation in the depth of the groove along the length of the groove. For example, for every one millimeter increase in the depth of the groove, the width of the groove also increases by one millimeter. According to another example, the depth of the groove may vary at a multiple of the variation of the width of the groove along the length of the groove. For example, for every one millimeter increase in the depth of the groove, the width of the groove increases by 0.5 millimeter. Thus, the variation in the depth of each groove may linearly relate to the variation in the width of each groove along the length of each groove.
FIG. 63 shows a typical cutting bit 5300 having a cutting blade 5301 for cutting a groove in a material. A machine spins the cutting bit 5300 so that the cutting blade 5301 can cut a hole in a material, and the machine moves the material being cut or moves the cutting bit 5300 to create a groove along the path of movement. The cutting bit 5300 has an angle 5302, which defines the angle 5304 of the groove cut by the cutting blade 5301 as shown in FIGS. 64 and 65. The example cutting bit of FIG. 63 has an angle 5302 of about 90°, which can cut a groove as shown in FIG. 65 with an angle 5304 of about 90°. FIG. 64 shows a groove having a groove angle 5304 of about 60°. A cutting bit (not shown) for cutting the groove of FIG. 64 has a cutting bit with an angle of about 60°.
Denoting the depth of each groove by y, the width of each groove by x, and the angle of the cutting blade by α, a relationship between the depth of each groove and the width of each groove along the length of each groove may be expressed by:




  
    
      
        x
        =
        
          2
          ⁢
          
            
          
          ⁢
          y
          ⁢
          
            
          
          ⁢
          
            tan
            ⁡
            
              (
              
                α
                2
              
              )
            
          
        
      
    
    
      
        (
        1
        )
      
    
  




The variation of the width of each groove relative to the depth of each groove along the length of the groove may be expressed by:




  
    
      
        
          dx
          dy
        
        =
        
          2
          ⁢
          
            
          
          ⁢
          
            tan
            ⁡
            
              (
              
                α
                2
              
              )
            
          
        
      
    
    
      
        (
        2
        )
      
    
  




According to equation (2), when the cutting blade 5301 has an angle of 90°, the width of the groove varies relative to depth of the groove by a factor of 2 along the length of the groove. For example, for every 1 millimeter increase in the depth of the groove, the width of the groove increases by 2 millimeters. When the cutting blade has an angle of 60°, the width of the groove varies relative to the depth of the groove by a factor of about 1.15. For example, for every 1 millimeter increase in the depth of the groove, the width of the groove increases by 1.15 millimeters. When the cutting blade has an angle of 30°, the width of the groove varies relative to the depth of the groove by a factor of about 0.54. For example for every 1 millimeter increase in the depth of the groove, the width of the groove increases by about 0.54 millimeters. Thus, cutting each groove with a cutting tool provides a groove having a width and depth that vary linearly relative to each other along the length of the groove.
According to equation (2), the width profile of a groove as shown in FIG. 61 may be similar in shape to the depth profile of the groove according to FIG. 62. In other words, as the groove becomes deeper from one end wall 5250 or 5252 to the center portion of the groove, the width of the groove also increases by a factor that is associated with the angle of the groove or the cutting tool. Thus, the width of the groove varies linearly relative to a variation in the depth of the groove along the length of the groove, and the width and depth profiles of the groove may be similar.
According to equation (2), the variation in the depth of the groove relative to the variation in the width of the groove is linear. However, the variation in the depth of the groove relative to the variation in the width of the groove may be constant or nonlinear. One or more cutting tools for manufacturing a groove may be used such that the depth of the groove varies relative to a variation in the width of the groove according to a non-linear relationship. For example, the variation in the depth of a groove relative to variation in the width of the groove may be defined by the following equation:




  
    
      
        
          dx
          dy
        
        =
        
          1
          
            y
          
        
      
    
    
      
        (
        3
        )
      
    
  




According to equation (3), the width of the groove is twice the square root of the depth of the groove, which can be represented by the following equation:

x=2√{square root over (y)}  (4)

Thus, the relationship between the variation in depth and the variation in width of the groove may be nonlinear. According to another embodiment, the depth and/or the cross-sectional shape of a groove may vary, but the width of the groove may remain constant. For example, the groove may have a square cross-sectional shape with the depth of the groove varying from one end of the groove to the other end of the groove while the width of the groove remains constant. According to another example, the width of the groove may remain constant from one end of the groove to the other end of the groove, but the cross-sectional shape and/or depth of the groove may vary from one end of the groove to the other end of the groove. According to another embodiment, the depth of the groove from one end of the groove to the other end of the groove may remain constant, while the width of the groove varies and/or remains constant from one end of the groove to the other end of the groove.
According to another example shown in FIGS. 66 and 67, the depth 5355 of a groove 5320 may be constant along a portion of the groove, such as a center portion 5356 of the groove. Accordingly, the width 5380 of the groove is also constant as described in detail above along the center portion of the groove 5356. To manufacture the groove 5320 of FIGS. 66 and 67, a cutting tool such as the cutting tool 5300 is used at a constant depth 5355 at the center portion 5356 of the groove, hence resulting in a constant width 5380 at the center portion 5356 of the groove 5320.
The groove areas with deeper and wider grooves near the center of mass of a putter may provide a higher expected ball speed, while shallower and narrower groove areas near the toe portion and the heel portion may provide a lower expected ball speed. Furthermore, the greater groove width and depth at a center portion of a putter may reduce the mass at a point of contact with the golf ball, thereby normalizing the ball speed across the putter face by equating point mass at each possible point of contact, such that even on off-center hits: toe, heel, high, or low, the ball speed would be generally the same as if impacted on the center of the putter face.
The cutting tool of FIG. 63 is an example cutting tool. Other cutting tools may be used that may have different shapes, and therefore resulting in different shape grooves. The cutting tool of FIG. 63 is V-shaped, which results in a V-shaped groove. However, a U-shaped cutting tool (not shown) may result in a U-shaped groove. According to one embodiment, a cutting tool may be used that has a flat tip or point for manufacturing a flat-bottom groove. For example, the cutting tool may be a V-shaped cutting tool that has a flat tip instead of a pointed tip. Accordingly, a V-shaped groove can be manufactured having a flat bottom. Thus, the bottom of a groove may be substantially a point (i.e., having almost no width) to being as wide as the width of the groove (i.e., rectangular or square cross-sectional groove shape). According to one example, the bottom of the groove may be flat and have a width of about 0.003 inches (0.0076 centimeters). A groove having a flat bottom may improve putting performance. A groove may be manufactured by using one cutting tool as described above or a plurality of cutting tools. For example, a plurality of cutting tools may be used to manufacture a single groove to provide different groove cross-sectional shapes and/or dimensions from one end of the groove to the other end of the groove.
As the rules to golf may change from time to time (e.g., new regulations may be adopted or old rules may be eliminated or modified by golf standard organizations and/or governing bodies), golf equipment related to the methods, apparatus, and/or articles of manufacture described herein may be conforming or non-conforming to the rules of golf at any particular time. Accordingly, golf equipment related to the methods, apparatus, and/or articles of manufacture described herein may be advertised, offered for sale, and/or sold as conforming or non-conforming golf equipment. The methods, apparatus, and/or articles of manufacture described herein are not limited in this regard.
Although a particular order of actions is described above, these actions may be performed in other temporal sequences. For example, two or more actions described above may be performed sequentially, concurrently, or simultaneously. Alternatively, two or more actions may be performed in reversed order. Further, one or more actions described above may not be performed at all. The apparatus, methods, and articles of manufacture described herein are not limited in this regard.
While the invention has been described in connection with various aspects, it will be understood that the invention is capable of further modifications. This application is intended to cover any variations, uses or adaptation of the invention following, in general, the principles of the invention, and including such departures from the present disclosure as come within the known and customary practice within the art to which the invention pertains.

## Claims

1. A golf club head comprising:
a body portion having a body central region, a body toe portion, a body heel portion, a body top rail portion and a body sole portion;
a club face on the body portion comprising grooves extending from a center portion of the club face toward the body heel portion and from the center portion of the club face toward the body toe portion,
a depth of at least one groove extending in a face-rear direction;
a length of at least one groove extending in a heel-toe direction; and
a width of at least one groove extending in a top rail-sole direction;
each groove having a depth portion defining a largest depth of the groove, the depth portion having a depth portion length extending in a direction from the body heel portion to the body toe portion;
wherein a change in the depth of at least one groove along the length of the groove is linear relative to a change in the width of the at least one groove along the length of the groove;
wherein the depth of each groove increases from a groove heel portion to the depth portion;
wherein the depth of each groove increases from a groove toe portion to the depth portion;
wherein the width of each groove increases from the groove heel portion to the depth portion;
wherein the width of each groove increases from the groove toe portion to the depth portion;
wherein the depth portion lengths of at least two of the grooves located between the body top rail portion and the body central region increase in a direction from the body top rail to the central region; and
wherein the depth portion lengths of at least two of the grooves located between the body sole portion and the body central region increase in a direction from the body sole portion to the central region.

2. The golf club head of claim 1, wherein the width of each groove is constant at the depth portion.

3. The golf club head of claim 1, wherein:
the at least one groove has a v-shaped cross section; and
the change in the width of the at least one groove along the length of the groove varies relative to the change in the depth of the at least one groove along the length of the groove by a factor of approximately 1.15.

4. The golf club head of claim 1, wherein the at least one groove has a flat bottom.

5. The golf club head of claim 1, wherein cross sectional configurations of at least two of the grooves vary between at least one of the body heel portion and the body toe portion or the body top rail portion and the body sole portion.

6. The golf club head of claim 1, wherein the club face is detachably attached to the body portion.

7. The golf club head of claim 1, wherein the at least one groove is manufactured on the club face with a v-shaped cutting tool.

8. The golf club head of claim 1, wherein the grooves increase in depth in a direction from the body top rail portion toward the center portion and in a direction from the body sole portion toward the center portion.

9. A golf club head comprising:
a body portion having a body central region, a body toe portion, a body heel portion, a body top rail portion and a body sole portion;
a club face on the body portion comprising grooves extending from a center portion of the club face toward the body heel portion and from the center portion of the club face toward the body toe portion,
a depth of at least one groove extending in a face-rear direction;
a length of at least one groove extending in a heel-toe direction; and
a width of at least one groove extending in a top rail-sole direction;
each groove having a depth portion defining a largest depth of the groove, the depth portion having a depth portion length extending in a direction from the body heel portion to the body toe portion;
wherein a change in the depth of at least one groove along the length of the groove is linear relative to a change in the width of the at least one groove along the length of the groove;
wherein the grooves increase in depth in a direction from the body top rail portion toward the center portion and in a direction from the body sole portion toward the center portion;
wherein the at least one groove has a v-shaped cross section;
wherein the depth of each groove increases from a groove heel portion to the depth portion;
wherein the depth of each groove increases from a groove toe portion to the depth portion;
wherein the width of each groove increases from the groove heel portion to the depth portion;
wherein the width of each groove increases from the groove toe portion to the depth portion;
wherein the depth portion lengths of at least two of the grooves located between the body top rail portion and the body central region increase in a direction from the body top rail to the central region; and
wherein the depth portion lengths of at least two of the grooves located between the body sole portion and the body central region increase in a direction from the body sole portion to the central region.

10. The golf club head of claim 9, wherein the width of each groove is constant at the depth portion.

11. The golf club head of claim 9, wherein cross sectional configurations of at least two of the grooves vary between at least one of the body heel portion and the body toe portion or the body top rail portion and the body sole portion.

12. The golf club head of claim 9, wherein the change in the width of the at least one groove along the length of the groove varies relative to the change in the depth of the at least one groove along the length of the groove by a factor of approximately 1.15.

13. The golf club head of claim 9, wherein the at least one groove is manufactured on the club face with a v-shaped cutting tool.

14. The golf club head of claim 9, wherein the at least one groove has a flat bottom.

15. A golf club head comprising:
a body portion having a body central region, a body toe portion, a body heel portion, a body top rail portion and a body sole portion;
a club face on the body portion comprising grooves extending from a center portion of the club face toward the body heel portion and from the center portion of the club face toward the body toe portion,
a depth of at least one groove extending in a face-rear direction;
a length of at least one groove extending in a heel-toe direction; and
a width of at least one groove extending in a top rail-sole direction;
each groove having a depth portion defining a largest depth of the groove, the depth portion having a depth portion length extending in a direction from the body heel portion to the body toe portion;
wherein a change in the depth of at least one groove along the length of the groove is linear relative to a change in the width of the at least one groove along the length of the groove;
wherein the width of each groove is constant at the depth portion;
wherein the at least one groove has a v-shaped cross section;
wherein the depth of each groove increases from a groove heel portion to the depth portion;
wherein the depth of each groove increases from a groove toe portion to the depth portion;
wherein the width of each groove increases from the groove heel portion to the depth portion;
wherein the width of each groove increases from the groove toe portion to the depth portion;
wherein the depth portion lengths of at least two of the grooves located between the body top rail portion and the body central region increase in a direction from the body top rail to the central region; and
wherein the depth portion lengths of at least two of the grooves located between the body sole portion and the body central region increase in a direction from the body sole portion to the central region.

16. The golf club head of claim 15, wherein cross sectional configurations of at least two of the grooves vary between at least one of the body heel portion and the body toe portion or the body top rail portion and the body sole portion.

17. The golf club head of claim 15, wherein the club face is detachably attached to the body portion.

18. The golf club head of claim 15, wherein the at least one groove is manufactured on the club face with a v-shaped cutting tool.

19. The golf club head of claim 15, wherein the at least one groove has a flat bottom.

20. The golf club head of claim 15, wherein the grooves increase in depth in a direction from the body top rail portion toward the center portion and in a direction from the body sole portion toward the center portion.