The present invention provides: a carbon fiber bundle which exhibits excellent filament shape stability when forming a composite material, and a carbon fiber composite material which exhibits high tensile strength; and a method for producing the same. The provided carbon fiber bundle exhibits a tensile elasticity as a resin-impregnated strand of 265-300 GPa, a tensile strength as a resin-impregnated strand of 6.0 GPa or more, a knot strength of 820 N/mm.sup.2 or more, a filament number of 30,000 or more, and an average tear distance of 600-850 mm, wherein the rate of change in filament width is 8% or less when the carbon fiber bundle is unraveled under the conditions stipulated in the description, and there are four or fewer sections per 1,000 m which exhibit a filament width equal to or less than 75% of the average filament width when the carbon fiber bundle is unraveled under the conditions stipulated in the description.

A spindle unit includes a support shaft, an electromagnetic air-gap brake, a spindle member, and a coupler. The support shaft is attached to the stationary frame of a creel. The brake is connected to the front end of the support shaft. The spindle member is rotatably supported by the support shaft in a state in which the support shaft and the brake are inserted in the spindle member. The coupler couples the spindle member and the brake shaft.

A filament winding apparatus winds, around a workpiece, a fiber bundle formed by bundling a plurality of fibers. The filament winding apparatus includes a widening roller that rotates while making contact with the fiber bundle that is being conveyed. The widening roller has, provided on the peripheral surface, a plurality of projecting ridges extending in the axial direction, the projecting ridges being arranged side by side in the circumferential direction. The projecting ridges make contact with the fiber bundle to thereby widen the fiber bundle.

A manufacturing method and an apparatus enable high productivity. A method for manufacturing an oxidized fiber bundle includes joining an upstream precursor fiber bundle and a downstream precursor fiber bundle together with a joining fiber bundle, and oxidizing the joined precursor fiber bundles by feeding the joined precursor fiber bundles through an oxidization furnace. The joining includes applying an oiling agent to a joint area of a joining target precursor fiber bundle before joining the joining target precursor fiber bundle and the joining fiber bundle together. A quantity of the oiling agent adhering to the joint area is 0.15 to 0.85 wt %.

There is provide a process for unwinding material from a spool (2) wherein the angle () of take off at the first contact point (4) for the unwind is always in the range 020, and wherein the first contact point (4) for the unwind is no more than 600 mm from the axis (3) of rotation of the spool (2). There is also provided an apparatus for the unwinding of material from a spool (2) comprising an axis (3) upon which a spool (2) may be rotatably mounted and a static first contact point (4) for the unwound material positioned no more than 600 mm from the centre of the axis (3), wherein the angle () of take off at the first contact point (4) for the unwind is always in the range 020.

A fiber coil mounting device is used in automated composite material layup equipment. The fiber coil mounting device includes a fiber coil mounting shaft with axial hollow structure, a fiber stop plate disposed on two sides of the fiber coil mounting shaft, and an anti-slide fiber coil tightening mechanism. The anti-slide fiber coil tightening mechanism includes a piston assembly disposed inside the axial hollow structure, a spring piece disposed on the piston assembly, a driving unit controlling an axial slide of the piston assembly, and a tightening unit driven by an axial force produced by the spring piece during the axial slide of the piston assembly.

A process and apparatus for separating a carbon filament tow into a set of reduced filament count bundles. The process includes feeding a tow of carbon filaments into a guide array, mechanically splitting the tow within the guide array into filament bundles, removing a coating from the filament bundles, feeding the filament bundles into a guide pin assembly to separate the filament bundles with a reduced filament count from one another, applying a false twist to the filament bundles to loosen individual filaments then recombining the individual filaments of each filament bundle into a re-bundled ribbon. Coatings may be applied to each re-bundled ribbon prior to winding each re-bundled ribbon onto a take-up.

A method for producing yarns separated from reinforcing fiber strands including a process of intermittently separating fibers of the reinforcing fiber strands.

Systems include a creel assembly supporting a plurality of spools containing at least one cord having an indeterminate length such that a plurality of cords are supported on the creel assembly. A tensioner assembly operative to tension approximately equal predetermined lengths of the plurality of cords received from the creel assembly. A building mandrel supported for rotation and translation. A head assembly supported in fixed relation to the building mandrel. The head assembly is positioned co-axially such that the building mandrel can pass through an opening in the head assembly during translation. Methods of manufacture are included, as are flexible spring members and gas spring assemblies.

A fiber coil mounting device is used in automated composite material layup equipment. The fiber coil mounting device includes a fiber coil mounting shaft with axial hollow structure, a fiber stop plate disposed on two sides of the fiber coil mounting shaft, and an anti-slide fiber coil tightening mechanism. The anti-slide fiber coil tightening mechanism includes a piston assembly disposed inside the axial hollow structure, a spring piece disposed on the piston assembly, a driving unit controlling an axial slide of the piston assembly, and a tightening unit driven by an axial force produced by the spring piece during the axial slide of the piston assembly.