Hello,
complet je sais pas mais c'est la réponse du royal & ancient.
Bubble a écrit :parce qu'on parle de driving heads
Dans le texte c'est écrit clubhead
Bubble a écrit :Note: (i) above does not apply to putters
Si c'est précisé pas pour les putters, c'est que c'est pour le reste, driver, bois, hybride, fer. Mais ceci n'est qu'interprétation.
Man
Le texte complet de l'USGA
4. Clubhead
a. Plain in Shape
The clubhead must be generally plain in shape. All parts must be rigid, structural in nature and functional. The clubhead or its parts must not be designed to resemble any other object. It is not practicable to define plain in shape precisely and comprehensively. However, features that are deemed to be in breach of this requirement and are therefore not permitted include, but are not limited to:
(i) All Clubs
holes through the face;
holes through the head (some exceptions may be made for putters and cavity back irons);
facsimiles of golf balls or actual golf balls incorporated into the head;
features that are for the purpose of meeting dimensional specifications;
features that extend into or ahead of the face;
features that extend significantly above the top line of the head;
furrows in or runners on the head that extend into the face (some exceptions may be made for putters); and
optical or electronic devices.
(ii) Woods and Irons
all features listed in (i) above;
cavities in the outline of the heel and/or the toe of the head that can be viewed from above;
severe or multiple cavities in the outline of the back of the head that can be viewed from above;
transparent material added to the head with the intention of rendering conforming a feature that is not otherwise permitted; and
features that extend beyond the outline of the head when viewed from above.
b. Dimensions, Volume and Moment of Inertia
(i) Woods
When the club is in a 60 degree lie angle, the dimensions of the clubhead must be such that:
the distance from the heel to the toe of the clubhead is greater than the distance from the face to the back;
the distance from the heel to the toe of the clubhead is not greater than 5 inches (127 mm); and
the distance from the sole to the crown of the clubhead, including any permitted features, is not greater than 2.8 inches (71.12 mm).
These dimensions are measured on horizontal lines between vertical projections of the outermost points of:
the heel and the toe; and
the face and the back (see Fig. VIII, dimension A);
and on vertical lines between the horizontal projections of the outermost points of the sole and the crown (see Fig. VIII, dimension B). If the outermost point of the heel is not clearly defined, it is deemed to be 0.875 inches (22.23 mm) above the horizontal plane on which the club is lying (see Fig. VIII, dimension C).
The volume of the clubhead must not exceed 460 cubic centimeters (28.06 cubic inches), plus a tolerance of 10 cubic centimeters (0.61 cubic inches).
When the club is in a 60 degree lie angle, the moment of inertia component around the vertical axis through the clubhead’s center of gravity must not exceed 5900 g cm2 (32.259 oz in2), plus a test tolerance of 100 g cm2 (0.547 oz in2).
(ii) Irons
When the clubhead is in its normal address position, the dimensions of the head must be such that the distance from the heel to the toe is greater than the distance from the face to the back.
(iii) Putters (see Fig. IX)
When the clubhead is in its normal address position, the dimensions of the head must be such that:
the distance from the heel to the toe is greater than the distance from the face to the back;
the distance from the heel to the toe of the head is less than or equal to 7 inches (177.8 mm);
the distance from the heel to the toe of the face is greater than or equal to two thirds of the distance from the face to the back of the head;
the distance from the heel to the toe of the face is greater than or equal to half of the distance from the heel to the toe of the head; and
the distance from the sole to the top of the head, including any permitted features, is less than or equal to 2.5 inches (63.5 mm).
For traditionally shaped heads, these dimensions will be measured on horizontal lines between vertical projections of the outermost points of:
the heel and the toe of the head;
the heel and the toe of the face; and
the face and the back;
and on vertical lines between the horizontal projections of the outermost points of the sole and the top of the head.
For unusually shaped heads, the toe to heel dimension may be made at the face.
c. Spring Effect and Dynamic Properties
The design, material and/or construction of, or any treatment to, the clubhead (which includes the club face) must not:
(i) have the effect of a spring which exceeds the limit set forth in the Pendulum Test Protocol on file with the USGA; or
(ii) incorporate features or technology including, but not limited to, separate springs or spring features, that have the intent of, or the effect of, unduly influencing the clubhead’s spring effect; or
(iii) unduly influence the movement of the ball.
Note: (i) above does not apply to putters.
d. Striking Faces
The clubhead must have only one striking face, except that a putter may have two such faces if their characteristics are the same, and they are opposite each other.
5. Club Face
a. General
The face of the club must be hard and rigid and must not impart significantly more or less spin to the ball than a standard steel face (some exceptions may be made for putters). Except for such markings listed below, the club face must be smooth and must not have any degree of concavity.
b. Impact Area Roughness and Material
Except for markings specified in the following paragraphs, the surface roughness within the area where impact is intended (the “impact area”) must not exceed that of decorative sandblasting, or of fine milling (see Fig. X).
The whole of the impact area must be of the same material (exceptions may be made for clubheads made of wood).
c. Impact Area Markings
If a club has grooves and/or punch marks in the impact area they must meet the following specifications:
(i) Grooves
Grooves must be straight and parallel.
Grooves must have a symmetrical cross-section and have sides which do not converge (see Fig. XI).
*For clubs that have a loft angle greater than or equal to 25 degrees, grooves must have a plain cross-section.
The width, spacing and cross-section of the grooves must be consistent throughout the impact area (some exceptions may be made for woods).
The width (W) of each groove must not exceed 0.035 inches (0.9 mm), using the 30 degree method of measurement on file with the USGA.
The distance between edges of adjacent grooves (S) must not be less than three times the width of the grooves, and not less than 0.075 inches (1.905 mm).
The depth of each groove must not exceed 0.020 inches (0.508 mm).
*For clubs other than driving clubs, the cross-sectional area (A) of a groove divided by the groove pitch (W+S) must not exceed 0.0030 square inches per inch (0.0762 mm2/mm) (see Fig. XII).
Grooves must not have sharp edges or raised lips.
For clubs that have a loft angle greater than or equal to 25 degrees, groove edges must be substantially in the form of a round having an effective radius which is not less than 0.010 inches (0.254 mm) when measured as shown in Fig. XIII, and not greater than 0.020 inches (0.508 mm). Deviations in effective radius within 0.001 inches (0.0254 mm) are permissible.
(ii) Punch Marks
The maximum dimension of any punch mark must not exceed 0.075 inches (1.905 mm).
The distance between adjacent punch marks (or between punch marks and grooves) must not be less than 0.168 inches (4.27 mm), measured from center to center.
The depth of any punch mark must not exceed 0.040 inches (1.02 mm).
Punch marks must not have sharp edges or raised lips.
*For clubs that have a loft angle greater than or equal to 25 degrees, punch mark edges must be substantially in the form of a round having an effective radius which is not less than 0.010 inches (0.254 mm) when measured as shown in Figure XIII, and not greater than 0.020 inches (0.508 mm). Deviations in effective radius within 0.001 inches (0.0254 mm) are permissible.
Note 1: The groove and punch mark specifications above indicated by an asterisk (*) apply only to new models of clubs manufactured on or after January 1, 2010 and any club where the face markings have been purposely altered, for example, by re-grooving. For further information on the status of clubs available before January 1, 2010, please refer to the Informational Club Database at
www.USGA.org .
Note 2: The Committee may require, in the conditions of competition, that the clubs the player carries must conform to the groove and punch mark specifications above indicated by an asterisk (*). This condition is recommended only for competitions involving expert players. For further information, refer to Decision 4-1/1 in ‘‘Decisions on the Rules of Golf.”
d. Decorative Markings
The center of the impact area may be indicated by a design within the boundary of a square whose sides are 0.375 inches (9.53 mm) in length. Such a design must not unduly influence the movement of the ball. Decorative markings are permitted outside the impact area.
e. Non-Metallic Club Face Markings
The above specifications do not apply to clubheads made of wood on which the impact area of the face is of a material of hardness less than the hardness of metal and whose loft angle is 24 degrees or less, but markings which could unduly influence the movement of the ball are prohibited.
f. Putter Face Markings
Any markings on the face of a putter must not have sharp edges or raised lips. The specifications with regard to roughness, material and markings in the impact area do not apply.