Abstract: A hydraulic wrench has a support, and a drive assembly which is mounted thereon and which includes a shaft that is turnable, a pair of sector drive plates which are mounted on the shaft turnable relative to the same and spaced from one another, each drive plate having an arcuate edge face formed with a plurality of slots that are spaced about the axis of the shaft and extend substantially parallel to this axis, and a square drive member which is turnable with the shaft and can be inserted into a mating drive socket. A transmission arrangement transmits motion from the sector drive plates to the shaft in order to turn the latter when the sector drive plates are turned.