Abstract: Large impacts act on a spoke wheel and spokes fastened by nipples tend to be loosened when a racing off-road motorcycle and the like repeatedly jumps and lands. A hub is connected with a rim by using deformed spokes each having a deformed portion. The deformed spoke is fastened while being elastically deformed so that the deformed portion extends by the nipple. As compared to a straight spoke, the deformed spoke has low longitudinal elastic modulus and substantially the same stiffness with a spoke having an equal diameter.

Abstract: Large impacts act on a spoke wheel and spokes fastened by nipples tend to be loosened when a racing off-road motorcycle and the like repeatedly jumps and lands. A hub is connected with a rim by using deformed spokes each having a deformed portion. The deformed spoke is fastened while being elastically deformed so that the deformed portion extends by the nipple. As compared to a straight spoke, the deformed spoke has low longitudinal elastic modulus and substantially the same stiffness with a spoke having an equal diameter.

Abstract: A seal chain in which a sealing member having a shape of a “plus” in section is steadily twisted (turned) and deformed into a shape of an “X” and whose abrasion resistance and flexing torque are improved. The sealing member is formed such that inner diametric side end faces of third and fourth lip portions extending in a transverse direction from a center base portion extend in a direction orthogonal to a radial direction and outer diametric side end faces thereof are formed as tapered faces such that width of the lip portion is widened from an edge face toward the base portion. A diagonal distance of the center base portion is within a range of 0.8 to 1.0 of a clearance between inner and outer link plates.

Abstract: A highly durable and compact chain disconnecting and connecting tool that may be used for a chain at a sprocket part for winding the chain and that can receive an operational load at two places is provided. A first block has an engaged pressure actuating member coupling member. A second block is coupled with the first block turnably by the coupling member and has a cutout on one side and a through hole on another side of the block. The tool is attached to the chain from an opening while positioned engagement with an edge projection of a tap bolt that is screwed with the first block and with the cutout or the through hole.

Abstract: There is provided a highly durable and compact chain disconnecting and connecting tool that may be used for a chain at a sprocket part for winding the chain and that can receive an operational load at two places. A first block has a pressure actuating member screwed therewith and a coupling member fixed thereto. A second block is coupled with the first block turnably by the coupling member and has a closed-end hole on one side and a through hole on another side of the block. The tool is attached to the chain from an opening while positioned and engaging an edge projection of a tap bolt that is screwed with the first block with the closed-end hole or the through hole.

Abstract: There is provided a seal chain in which a sealing member having a shape of + in section is steadily twisted (turned) and deformed into a shape of X and whose abrasion resistance and flexing torque are improved. The sealing member is formed such that inner diametric side end faces of third and fourth lip portions extending in a transverse direction from a center base portion extend in a direction orthogonal to a radial direction and outer diametric side end faces thereof are formed as tapered faces such that width of said lip portion is widened from an edge face toward the base portion. A diagonal distance of the center base portion is within a range of 0.8 to 1.0 of a clearance between inner and outer link plates.

Abstract: A chain joint for a power transmission chain comprises a joint pin and a projecting bush having brims swelling outwardly both its ends with at least one a slit extending longitudinally through the bush. The projecting bush is inserted into a pin hole and a bush hole of the chain, and the joint pin is pressed in an inner hole of the projecting bush. Then, the projecting bush is spread outwardly due to the slit and fits in the pin hole perfectly. Furthermore, the brims engage with the outer link plates on their outsides to prevent the projecting bush from coming off.

Abstract: Disclosed is a power transmission chain formed of a series of articulated units, each including a number of interleaved links each having a pair of pin-receiving holes at predetermined intervals and pivotally connected to the links of adjacent units by pins loosely fitted in the pin-receiving holes. The links are engageable with sprocket teeth for power transmission and the links are formed in an assymetrical shape in the direction of the pitch line and relative to a center line through a median point between the pin-receiving holes by bulging of one of the inner flanks defining a crotch portion of the link toward the other flank, part of the links being connected in a reverse direction to provide a different mechanism from others in meshing engagement with sprocket teeth.