Abstract: A wrench includes a main rod, a rotating rod and a head portion. One end of the rotating rod is fixed to the main rod. The head portion includes an accommodating element, a sleeve mount, a driven gear and a driving gear. The accommodating element has a side opening. A periphery of the side opening extends outward to form an engaging portion. The main rod is rotatably mounted through the engaging portion. The sleeve mount is rotatably mounted in the accommodating element. The driven gear is fixed to the sleeve mount and is located in the accommodating element. The driving gear is fixed to the rotating rod and engaged with the driven gear. The sleeve mount is driven to tighten or loosen a nut by rotating the main rod to reduce an operating space for the wrench.

Abstract: A transmission assembly has a front transmission device, a rear transmission device, and a soft shaft connected to the front and rear transmission devices. Each transmission device has a fixed disk, a driving disk, a transmission gear, a casing, a connector, a bearing, a cushion, and a retarder. The driving disk is positioned on the fixed disk by a plurality of rivets. A large number of square holes are formed on the driving disk. The square hole receives a gear tooth of the transmission gear. The transmission gear and the retarder are connected pivotally. The retarder and a connector are connected pivotally also. The retarder comprises at least two intermeshed retarding gears. The connector is connected to the soft shaft. The transmission device is enclosed by a casing.