Abstract: A shift register includes a signal generating circuit for generating an output signal at an output end of the shift register in response to a clock signal while the signal generating circuit is turned on, a driving circuit electrically coupled to the signal generating circuit for controlling the signal generating circuit in response to an input signal received from an input end of the shift register, a primary reset circuit electrically coupled to the signal generating circuit for turning off the signal generating circuit and resetting the output signal from the output end, and a feedback circuit electrically coupled to the output end and the major reset circuit for controlling the primary reset circuit in response to the output signal and the clock signal.

Abstract: A bicycle rim includes a plurality of elongate slots each of which is composed of a first diameter portion and a second diameter portion which is smaller than the first diameter portion. A tube having threaded outer periphery is inserted in each elongate slot and a core piece is inserted through a passage in the tube. The tube has a flange engaged with an inside of the rim and a cover member covering each elongate slot has a threaded hole for being threadedly connected to the threaded outer periphery of the tube. A protrusion extends from a side of the cover member so as to be engaged with the first diameter portion while the tube is shifted to the second diameter portion. A spoke is inserted in the core piece and threadedly connected to a threaded inner periphery of the core piece.

Abstract: A wheel holder assembly includes a mounting frame fixedly mounted inside one bottom hole of the sole of a shoe, a wheel holder frame turned about a shaft in the mounting frame to hold a wheel between a received (the non-operative) position and an extended (the operative) position, a torsional spring adapted to support the wheel holder frame in the extended position, and a spring-supported, press pin-controlled locking device adapted to lock the wheel holder frame between the received position and the extended position.