摘要:
A perforated bat for playing games such as paddle tennis, tether ball and others, has a monolithic unstressed striking head which comprises a pair of outer lattices which form the striking surfaces; and these lattices are joined by a third internal core lattice which has at least one longitudinal and one lateral web spanning the two outer lattices.
摘要:
An FRP curved pipe, particularly suitable for an FRP racket, good in resin flowability and deaeration at the time of molding, less in surface defects and excellent in strength can be obtained by a structure comprising an inner layer including a reinforcing fiber and an outer layer including a non-woven fabric having a single fiber diameter of not greater than 20 .mu.m and a weight per unit area of not greater than 100 g/m.sup.2.
摘要:
A tennis racket having a striking surface and a handle in combination has a strung total weight of less than 245 g, an overall length larger than 70 cm, a free-free vibrational frequency in the first mode of more than 210 Hz, a center of gravity of more than 41 cm, and a dynamic center of gravity of more than 50 cm, measured from the handle end.
摘要:
A process of molding a racket frame having an evacuation stage for shrinking a lamination of an inner bladder, a tubular prepreg and an outer protective tube before closing a mold, and the reinforcing fibers of the prepreg are not cut by inner edges of the mold, thereby preventing the racket frame from burr due to the reinforcing fibers cut by the inner edges.
摘要:
A substantially tubular rigid golf club shaft made of a composite of structural fiber laminate in a resin matrix, the shaft comprising a grip portion, a medial portion and a head attachment portion, the grip portion having a upper grip end and a lower grip end and being constructed and configured for a grip to be mounted on said grip portion that covers the exterior surface of the grip portion and extends substantially the entire length of said grip portion from said upper grip end to said lower grip end, the medial portion having a upper medial end adjacent to the lower grip end and extending a lower medial end adjacent to the head attachment portion, the head attachment portion having a upper head attachment end and a lower head attachment end with the upper head attachment end adjacent to the lower medial end, the head attachment portion constructed and configured for a golf club head to be mounted on said head attachment portion, a step transition in the exterior surface of the shaft that abruptly increases the diameter of the shaft between the exposed medial portion and either or both the grip portion and the head attachment portion.
摘要:
A method for manufacturing an object having a potential {x} which is generated in response to a field {f} applied thereto is provided. The method includes the step of designing a geometric model of the object. A computerized mathematical model of the object is generated by discretizing the geometric model of the object into a plurality of finite elements and defining nodes at boundaries of the elements, wherein values of the field {f} and potential {x} are specified at the nodes. A material property matrix [k] is then calculated based on the relationship {f}=[k]{x}. Material property coefficients are then extracted from the material property matrix [k] for each finite element in the computerized mathematical model and the extracted material property coefficients are compared to material property coefficients for known materials to match the extracted material property coefficients to the material property coefficients for known materials. Manufacturing parameters corresponding to the matched material property coefficients are then determined. The object is then manufactured in accordance with the determined manufacturing parameters.
摘要:
A composite prepreg for producing a tennis racket, which is light and tough and superior in flexibility and vibration absorption abilities, comprises thermosetting resin and reinforcing fibers, wherein the reinforcing fibers are a combination of (a) aromatic polyamide or polyester fibers and (b) carbon fibers, the fibers (a) being formed into a first type of strand and the fibers (b) being formed into a second type of strand, the first and second types of strand being arranged with certain regularity. The present invention is also directed to a tennis racket comprising a circular frame constituting a ball hitting area and a shaft connecting with the circular frame, the frame and shaft having a plurality of layers structured so that at least one layer is formed from the above described composite prepreg.
摘要:
A monoshaft tennis racquet has a frame head that circumscribes a stringing area, and a shaft connected to the opposite ends of the head. Either the head or the shaft, and preferably both, are formed of a composite material. The racquet preferably has a head having a length of at least 12 inches, a maximum width of at least 9 inches, and a strung surface area of at least 90 square inches. Preferably also, the free space vibrational frequency perpendicular to the stringing plane is matched to the in-plane vibration frequency so as to provide a unique and desirable feel in the racquet. Preferably, the vibration frequency perpendicular to the stringing plane is within 10% of the in-plane vibration frequency, and most preferably within 5%.
摘要:
Ball game racket, especially tennis racket or squash racket has a frame made of plastics, which in the plane of stringing provided on the head is designed in two parts and whose halves exhibit a trough-shaped cross section profile--open toward central plane (M)--with a concave wall, whose two longitudinal sides, bordering the open side of the cross section profile, are adjacent to central plane (M). The halves are connected to one another by connecting pins, formed on the respective wall, as well as sleeve-like sections receiving them. The connecting pins and sleeve-like sections each merge directly into the wall in the area of longitudinal sides or alternately to this the frame halves, at least on some connecting pins provided on the head and/or sleeve-like sections, exhibit a distance from one another, and the strings forming the stringing are run around these connecting pins or sleeve-like sections.
摘要:
A bicycle frame of streamlined and aerodynamically shaped tubular members has the form of two open triangles with a common side. The entire frame may be formed as one continuous unit with a plurality of hollow junctions each common to two or more members for supporting a front wheel assembly, a pedal and chain wheels assembly, a seat assembly and a rear wheel assembly. The frame may be covered or visually open from the side. The tubular seat column member has a rear wall which is curved longitudinally with a radius that follows the circumference of the rear tire. The longitudinally curved rear wall also is concave in transverse cross-section to follow the transverse shape of the outer surface of the tire. One or more of the tubular frame members, including a pair of rear seat stays and a pair of rear chain stays may have non-circular aerodynamic shapes in transverse cross-section.