Abstract: A roller skate includes a fixing seat, a plurality of wheels, and a safety device mounted on the wheel. The safety device includes a safety member mounted on the fixing seat and urged on the wheel, so as to adjust a rotation speed of the wheel. Thus, the roller skate can be fixed on the ground without rotation by the safety device, so that the learner can stand on the roller skate without movement so as to practice his/her balance. In addition, the safety member is slightly loosened from the wheels, so that the wheels are rotated at a lower speed, thereby facilitating the learner practicing the skating skill.

Abstract: A wrench includes a drive head, a drive member, a plurality of locking teeth mounted on either one of the inner wall of the drive head and the drive member, and two locking devices located beside the drive member. An urging block is located between the two locking devices for pressing one of the two locking devices to engage with the drive member. Each of the locking devices includes two driving blocks each formed with a locking end engageable with the locking teeth to drive the drive member. The locking ends of the two driving blocks are respectively engaged with the locking teeth at different time. Thus, the locking device has a smaller driving angle for driving the drive member.

Abstract: A torque adjustable tool includes an active member and a passive member which is removably connected to the active member by two respective clutch portions. Driving power is connected to the active member and the passive member outputs a torque. A spring is mounted to the passive member and biased between an inner periphery of a control member mounted to the passive member and an enlarged portion of the passive member. The control member includes a clamping portion to which a locking member is threadedly mounted. By operating the locking member, the clamping portion can be clamped inward to be securely mounted to the passive member as one piece so as to completely transfer the torque from the driving power, or the clamping portion is opened outward such that the passive member can output a torque that is less than the force applied by the spring.