Abstract: An artificial shuttlecock feather for implanting in a circular ring shape into a shuttlecock base, including: a vane section and a rachis section having one end in an axial direction of the rachis section fixed to the base and supporting the vane section provided to another end side of the rachis section, a hole being formed in the vane section so as to penetrate the vane section, and a porosity of a first region of the vane section being lower than a porosity of a second region of the vane section, the first region spanning from an edge on the one end side in the axial direction to a predetermined position further toward the one end side than a center of vane section in the axial direction, the second region spanning from the predetermined position to an edge on the other end side in the axial direction.

Abstract: An artificial shuttlecock feather for implanting in a circular ring shape into a shuttlecock base, including: a vane section and a rachis section having one end in an axial direction of the rachis section fixed to the base and supporting the vane section provided to another end side of the rachis section, a hole being formed in the vane section so as to penetrate the vane section, and a porosity of a first region of the vane section being lower than a porosity of a second region of the vane section, the first region spanning from an edge on the one end side in the axial direction to a predetermined position further toward the one end side than a center of vane section in the axial direction, the second region spanning from the predetermined position to an edge on the other end side in the axial direction.

Abstract: An artificial shuttlecock feather for implanting in a circular ring shape into a shuttlecock base, including: a vane section and a rachis section having one end in an axial direction of the rachis section fixed to the base and supporting the vane section provided to another end side of the rachis section, a hole being formed in the vane section so as to penetrate the vane section, and a porosity of a first region of the vane section being lower than a porosity of a second region of the vane section, the first region spanning from an edge on the one end side in the axial direction to a predetermined position further toward the one end side than a center of vane section in the axial direction, the second region spanning from the predetermined position to an edge on the other end side in the axial direction.

Abstract: An artificial shuttlecock feather for implanting in a circular ring shape into a base of a shuttlecock, the artificial feather includes: a vane section; and a rachis section supporting the vane section, the rachis section being formed from a material having a Charpy impact strength of 30 kJ/m2 or greater and a flexural modulus of 4 GPa or greater, and preferably having a Charpy impact strength of 36 kJ/m2 or greater and a flexural modulus of 4.7 GPa or greater.

Abstract: An artificial shuttlecock feather for implanting in a circular ring shape into a base of a shuttlecock, the artificial feather includes: a vane section; and a rachis section supporting the vane section, the rachis section being formed from a material having a Charpy impact strength of 30 kJ/m2 or greater and a flexural modulus of 4 GPa or greater, and preferably having a Charpy impact strength of 36 kJ/m2 or greater and a flexural modulus of 4.7 GPa or greater.

Abstract: An artificial shuttlecock feather that is to be implanted in a circular ring shape into a base of a shuttlecock, the artificial shuttlecock feather includes: a vane section; and a rachis section having one end in an axial direction of the rachis section fixed to the base and supporting the vane section provided to another end side of the rachis section, a hole being formed in the vane section so as to penetrate the vane section, and a porosity of a first region of the vane section being lower than a porosity of a second region of the vane section, the first region spanning from an edge on the one end side in the axial direction to a predetermined position further toward the one end side than a center of vane section in the axial direction, the second region spanning from the predetermined position to an edge on the other end side in the axial direction.

Abstract: A string set is a string set strung on a racket as a main string and a cross string, and is configured to include a first string strung as any one of the main string and the cross string and has a small friction force and a small diameter and a second string strung as another one of the main string and the cross string and has a larger friction force and a larger diameter than the diameter and the surface friction force of the first string. This distributes functions to the first string and the second string to obtain both the hairpin performance, which is improved by the large surface friction force and outer diameter of the string, and the cut smash performance, which is improved by the small surface friction force and outer diameter of the string, at the same time.

Abstract: A vehicle body suspension system comprising a piston-cylinder assembly provided between a vehicle wheel and a vehicle body. The piston, which is disposed within the cylinder connected to the wheel, and the piston rod coupled to the piston, are each formed with an oil channel extending axially therethrough. The end of the piston rod which is remote from the piston is connected to the vehicle body by means of an annular elastic member arranged around such end of the piston rod. An oil chamber having a variable volume is provided, and has part of its peripheral wall formed by part of the elastic member. A first damper arrangement is provided between the oil chamber and the oil channel for action during contraction of the system, and a second damper arrangement is provided in the piston for action during elongation of the system. An auxiliary vehicle body suspension spring is provided between the cylinder and the piston rod.

Abstract: A shock absorber for bumpers comprising a fixed bottomed outer cylinder and an inner cylinder which is slidably fitted in said outer cylinder and to the front end of which a bumper is to be fitted, said outer cylinder being provided with a stopper to prevent the inner cylinder from escaping and said inner cylinder being slidably fitted with a piston having damping force generating holes, filled with a compressible fluid and engaged with said stopper, said fluid being compressed by pulling a piston rod connected with the piston in the end part through the base end of the inner cylinder so as to collide with the bottom surface of the outer cylinder to press the inner cylinder into the outer cylinder.

Abstract: A shock absorber for bumpers comprising an inner cylinder having means at the front end for fitting the shock absorber to a bumper and the base part being slidably engaged in an outer cylinder having means for fitting it to a car frame; a high pressure gas enclosed between a free piston fitted in the inner cylinder and the front end of the inner cylinder; oil contained between the free piston and the botton surface of the outer cylinder so that no air gap produced, a tubular column fitted at its base end to the botton surface of the outer cylinder and provided with a plurality of side-by-side damping force generating holes, the front end being flexible engaged to the base end of the inner cylinder, and a plate-shaped valve slidably fitted on the tubular column is, opposed to the base end surface of the inner cylinder.