Abstract: The invention is directed to a motor-driven apparatus such as a motor-driven chain saw or the like. It includes a lubricating-oil pump and an oil supply for a work tool and is equipped with a device for interrupting the supply of oil to the tool. This facilitates use of the chain saw apparatus with an accessory attachment work tool such as a hedge trimmer, drilling tool or the like for which a flow of lubricating oil is unnecessary.

Abstract: A power saw having a throttle lever which is pivotally mounted on a handle, and having a throttle-knob for starting. In order to lock the throttle lever in a position in which the throttle is partially open, the throttle-knob for starting can be shifted by means of a blocking movement into the region of the path along which the throttle lever pivots. At least one additional movement precedes the blocking movement of the throttle-knob for starting, this additional movement preferably being a rotary movement which is directed about an axis of the throttle-knob for starting, and is directed essentially at right angles to the blocking movement.

Abstract: A power tool, especially power saw, having a two-stroke internal combustion engine, that is provided with a substantially horizontally arranged cylinder, a cooling air blower, with guide surfaces directed towards the belonging therewith and arranged on one side of the cylinder, and a muffler connected to the cylinder outlet. The muffler has an exhaust gas inlet conduit which is in communication with an expansion chamber of the muffler. At least part of the walls of the muffler which are subjected to exhaust gas emanating from the cylinder chamber belonging therewith are arranged, when viewed in the direction of flow of cooling air, before the cylinder of the motor and are adapted to present guide surfaces for a stream of cooling air.