Grommet and racket
To improve repulsion performance when a ball is hit by a racket. Grommets each include a strip-shaped portion and a cylinder portion protruding from one surface of the strip-shaped portion. The cylinder portion includes a plurality of ribs extending along an extending direction of a central axis of a cylinder main body. The plurality of ribs is constituted of first ribs protruding from an outer peripheral surface of the cylinder main body toward both sides in the extending direction of the strip-shaped portion, and second ribs protruding from the outer peripheral surface of the cylinder main body toward both sides in a direction orthogonal to the extending direction of the strip-shaped portion. Two or more of the first ribs are formed on each of the both sides in the extending direction of the strip-shaped portion, and one or more of the second ribs are formed on each of the both sides in the direction orthogonal to the extending direction of the strip-shaped portion.
1 . A racket, comprising:
a grommet that includes a strip-shaped portion extending in a predetermined direction and cylinder portions that protrude from one surface of the strip-shaped portion; and
a loop-shaped frame on which a string is extended in a tensioned state in a vertical direction and a lateral direction,
wherein each of the cylinder portions is received within a respective hole formed in the frame so as to mount the grommet on the frame, and the string extends through each of the cylinder portions so as to be maintained in the tensioned state, wherein
at least one of the cylinder portions comprises:
a cylinder main body through which the string extends in a state in which the cylinder main body is positioned in the respective hole formed in the frame,
ribs formed on an outer peripheral surface of the cylinder main body, wherein the ribs protrude outwardly from the outer peripheral surface and extend along an extending direction of a central axis of the cylinder main body,
the ribs including first ribs that protrude from the outer peripheral surface of the cylinder main body at an incline and generally in an extending direction of the strip-shaped portion, and the ribs including second ribs that protrude from the outer peripheral surface of the cylinder main body in a direction orthogonal to the extending direction of the strip-shaped portion,
at least two of the first ribs are formed on each of first opposing curved face regions of the outer peripheral surface of the cylinder main body,
at least one of the second ribs is formed on each of second opposing curved face regions of the outer peripheral surface of the cylinder main body, and
a tip end of each of the ribs, in respective protruding directions of the ribs, contacts an inner peripheral surface of the respective hole formed in the frame.
2 . The racket according to claim 1 , wherein
the first ribs are constituted by two first ribs formed on each of the first opposing curved face regions of the outer peripheral surface of the cylinder main body, and the second ribs are constituted by one second rib formed on each of the second opposing curved face regions of the outer peripheral surface of the cylinder main body.
3 . The racket according to claim 1 , wherein
the at least one of the cylinder portions having the ribs comprises a cylinder portion located at a central region of the frame.