Abstract: The invention relates to a construction machine, in particular drilling rig, comprising a mast, along which a tool is movably mounted, wherein the tool is suspended on a cable which can be actuated by means of cable winch for raising and lowering the tool, which cable winch is driven by an electric motor, as a winch drive, in a drive mode, wherein the electric motor is designed for operating in a recuperation mode in which the electric motor preferably generates electrical energy when the tool is lowered and outputs said electrical energy to an energy store, and a controller, which is designed to actuate the electric motor, depending on a specifiable target value, in such a way that the cable is tensioned both in the drive mode and in the recuperation mode of the electric motor.

Abstract: The bypass clutch in the fluid-containing housing of the hydrokinetic torque converter in the power train of a motor vehicle is provided with a first friction surface carried by a radially extending or conical section of the housing, and with a complementary friction surface carried by an axially movable piston or by an intermediate clutch plate of the bypass clutch. At least one of the friction surfaces is provided with an array of pockets and/or channels for a fluid (such as oil) which withdraws friction heat developing when the bypass clutch is partially engaged so that the friction surfaces contact but slip relative to each other. The depth and/or the width of the channels is at least substantially constant, and such channels can include bends between straight channel sections. The inlets of the channels can be located at the radially inner or radially outer marginal portion and their outlets can be located at the radially outer or inner marginal portion of the respective friction surface.