Yamaha Corporation

Toshiharu Fukushima

Kunimasa Muroi

Kunio Hiyama

Tatsuya Hiraku

Akio Yamamoto

Katsunori Suzuki

Hiroshi Nakaya

Masuhiro Okada

Takashi Okada

Kazushi Nakai

Eizi Abe

Kaoru Yoshioka

Takako Itoh

A method of fabricating a bow stick includes winding a prepreg, in which a fiber is impregnated with a resin, on a mandrel with a diameter gradually decreasing toward a distal end, setting a semi-fabricated product, in which the prepreg is wound on the mandrel, into a mold and molding the semi-fabricated product in a shape corresponding to a cavity formed between the mold and the mandrel by heating and pressurizing the semi-fabricated product in the mold, and taking out the mandrel from a molded product molded in the shape corresponding to the cavity to acquire a long and hollow stick body. When adjusting at least one of a weight distribution, a center of gravity, and a weight of the stick body, the volume of the cavity is changed using the mandrel of which the diameter or the diameter variation is gradually changed in an axis direction.

Method of fabricating bow stick of stringed instrument and bow stick of stringed instrument

A stick of a string instrument bow includes a base material having an arched-rod shaped carbon fiber resin layer made of carbon fiber resin and a glass fiber resin layer which covers the outer surface of the carbon fiber resin layer and is made of glass fiber resin, and the glass fiber resin layer has a non-adhesion portion formed of an air layer present within the glass fiber resin layer and an adhesion portion which does not include the air layer.

Stick of string instrument bow, string instrument bow and methods of manufacturing stick of string instrument bow

The present invention relates to a molding method characterized by kneading a binder comprising an agar having an average molecular weight of 30,000 to 150,000 with a metal powder, a ceramic powder, or a mixed powder thereof, injection-molding the thus obtained molding composition into a green body, removing at least the water from the green body, and then sintering the green body to obtain a molded product.

Binder for injection molding of metal powder or ceramic powder and molding composition and molding method wherein the same is used

A ribbon-shaped material for FRTP molded objects 1 having a laminate 4 in which a ribbon-shaped reinforcing fiber tow 2 is placed between thermoplastic resin films for supplying matrix resin which are wider than the ribbon-shaped reinforcing fiber tow 2, and in which the thermoplastic resin films 3,3 are fused in side portions 5,5 of the laminate 4, which are along the longitudinal direction of the laminate 4; and a wide material for FRTP molded objects 30,40 obtained by arranging a plurality of the ribbon-shaped materials for FRTP molded objects 1 whereby adjacent ribbon-shaped materials for FRTP molded objects 1,1 overlap each other in a manner such that the side portion 5 of one of the adjacent ribbon-shaped materials for FRTP molded objects 1 is placed on the side portion 5 or the middle portion 6 of the other along the longitudinal direction, and fusing together each overlapping portion 31,41 of the ribbon-shaped materials for FRTP molded objects 1, whereby the reinforcing fiber tows 2 are arranged in parallel; are advantageous in providing excellent impregnation of the reinforcing fiber with the thermoplastic resin, giving a great freedom of design, providing easy handling, creating no fuzz of the reinforcing fiber, and being flexible. Using such a material for FRTP molded objects 1,30,40, an inexpensive FRTP tubular molded object having a superior strength can be produced.

Material for FRTP molded objects and FRTP tubular molded object

A structure of synthetic resin foam has a core layer of thermoplastic resin foam and skin layers of non-foamed thermoplastic resin merged with the core layer, and the skin layers gives rise to increase the mechanical strength of the structure.

High-strength synthetic resin foam and process of fabrication thereof

A pre-impregnation has a ribbon-shaped tow of reinforcing fibers and a ribbon of thermoplastic resin laminated on the ribbon-shaped tow and fixed thereto at intervals, and the thermoplastic resin is allowed to uniformly impregnate into the ribbon-shaped tow under heat application so that a void does not take place in the ribbon-shaped tow.

Stong flexible pre-impregnation of fiber reinforced thermoplastic resin

A prepreg for a sleeve member of fiber reinforced thermoplastic resin available for a tennis racket or a golf club is woven by using ribbon-shaped reinforcing fiber tows/uni-directional commingle yarns and matrix fiber tows, and the ribbon-shaped reinforcing fiber tows/commingle yarns make the prepreg and, accordingly, the sleeve product thin, light, highly dense, economical and large in mechanical strength.

Prepreg available for fiber reinforced thermoplastic resin and process

Strong flexible pre-inpregnation of fiber reinforced thermoplastic resin

Strong flexible pre-impregnation of fiber reinforced thermoplastic resin

Using a fiber reinforced thermoplastic resin, component materials of shapes obtained by partitioning the shape of the desired hollow article into a plurality of parts are molded. Reinforcing members 5, made of a prepreg wherein reinforcing fiber is impregnated with thermoplastic resin, are affixed to the junctions of these component materials 1. These are housed within mold 7 as a hollow provisional assembly and a joined unitary body is formed by adding pressure and heating. Using the method of the present invention, it is possible to efficiently manufacture a complicatedly shaped hollow article, the obtained molded article being one which excels in mechanical strength and, moreover, has a surface which is continuous and smooth.

Method for manufacturing fiber reinforced thermoplastic resin molded

The present invention provides a carbon-fiber reinforced thermoplastic resin (CFRTP) having excellent adhesion between a carbon fiber, used therein as a reinforcing material, and a thermoplastic resin, used therein as a matrix. A carbodiimide agent is employed in order to achieve the above object. By the present invention, the carbodiimide agent is adhered to a carbon fiber for a reinforcing material, and the thus-treated carbon fiber is combined with a matrix thermoplastic resin; or the carbodimide agent is mixed with a matrix thermoplastic resin, and the mixture is combined with a carbon fiber for a reinforcing material. The carbodiimide agent enhances adhesion between the carbon fiber and the matrix thermoplastic resin. Accordingly, superior mechanical properties of the carbon fiber is sufficiently exploited in the CFRTP produced according to the present invention; therefore, the CFRTP of the present invention is an excellent composite material having superior mechanical strength.

Carbodiimide treated carbon fiber and use thereof

In composition of a copolymer making up a fitting pad for ski boots containing, as the major component, vinyl acetate, an acrylic component and ethylene, the content ratio of components other than ethylene is 20% or larger and the average molecular weight is 30,000 or smaller. The specified content ratio of the component other than ethylene and average molecular weight results in good fitness to a skier's foot thanks to good fluidization of the fitting material during application process, thereby assuring painless use even for a long period and good transmission of the movement of the skier's leg to the ski.

Growing community of inventors

Hamamatsu, Japan

Toshiharu Fukushima