Abstract: The invention relates to a portable handheld tool such as a motor chain saw, cutoff machine or the like having a motor arranged in a housing. The motor drives a work tool via a drive pinion. The portable, handheld tool is provided with a handle arrangement for holding and guiding the tool with the handle arangement being decoupled from the motor system by antivibration elements. Soft antivibration elements are required to obtain high isolation; whereas, the antivibration elements have to be as stiff as possible in order to reliably guide and hold the handheld tool. The antivibration elements holding the handle arrangement on the side of the drive pinion are arranged to lie approximately in a common plane. This arrangement makes it possible to use softer antivibration elements without the required stiffness for guiding and holding becoming too low.

Abstract: A handheld portable tool has a drive unit connected to the handle via damping elements. The drive unit includes an internal combustion engine having a crankshaft. To reduce the vibration transmitted by the drive unit to the handles, a static or dynamic imbalance of defined position and quantity is provided on the crankshaft of the engine, as a result of which vibration in the handles is considerably reduced. An imbalancing weight may for instance be provided in the fan wheel, so that the crankshaft and its elements are manufactured and balanced in the same manner as before, and only the fan wheel has to be structurally modified.

Abstract: A muffler, especially for a portable internal combustion engine, particularly for driving a motor chain saw, which muffler comprises an exhaust gas receiving chamber which is defined by a chamber wall and by a pan-shaped housing wall including an inlet for the exhaust gases. Arranged on the inside surface of the chamber wall there is arranged an exhaust gas conveying passage communicating with the exhaust gas chamber and being adapted to deflect an exhaust gas current by preferably 90.degree.. This passage is adapted to convey the thus deflected exhaust gas current through an aperture in the chamber wall. Above this aperture on the outside of the chamber wall and projecting therefrom there is provided a bend from which the exhaust gas current through an outlet in the bend flows at least approximately parallel to a portion of the chamber wall.

Abstract: Disclosed is an exhaust silencer suitable for use with portable combustion engines, and particularly for use with chain saw engines, comprising a chamber having an inlet and outlet for receiving the engine exhaust; means disposed about the chamber outlet for reducing the kinetic energy of the exhaust flowing therethrough; and an air duct means mounted exteriorly of the chamber below the chamber outlet for cooling the chamber, the kinetic energy reducing means, and the exhaust gas by contact with a stream of ambient air flowing therethrough.

Abstract: A rotor for a centrifugal clutch which rotor is designed as an axially laminated packet and is provided with a central supporting element carrying at least two circular segmental centrifugal weights respectively having one end thereof connected to the supporting element by an elastic supporting member.