Abstract: In a motor saw comprising an engine portion and a handle portion, the engine portion comprises a carburetor (17) located in a separate carburetor chamber (13) and connected to the cylinder (10) of the engine by means of a flexible inlet tube (18) passing through a partition wall (15) between the carburetor and the cylinder. For reducing vibrations transmitted to the carburetor, a supporting means is provided between the carburetor and the handle portion. The supporting means comprises a link (22) which is articulately connected to the carburetor as well as to the handle portion.

Abstract: When kick-backs occur on chain saws the cutter bar (36) is subjected to heavy forces, especially in the longitudinal direction. By putting in a piezo-electric crystal (37) at the cutter bar attachment in a place where the forces occur at kick-backs it can be effected that the crystal generates an electric impulse at sudden force changes, while the normally imposed screw powers do not give any signal. In this way it is possible to let the crystal trigger a mechanism (15) which releases the chain brake (14, 15) in an electrical way.

Abstract: A chain brake which is manually adjustable into a cocked position and releasable by means of stored electric energy and a trigger, includes a permanent magnet circuit in which a movable armature is a part of a latch which keeps the brake in the cocked position. The permanent magnet has a coil exerting a counter directional magnetic field to the permanent magnet when it passes current. The holding force on the latch decreases and the brake is released when current from a capacitor passes through the coil.

Abstract: Upon a kick-back of a motor saw, energy is transferred from the rotating parts of the engine into energy which generates the kick-back. This causes a tremendous decrease of the r.p.m. of the engine. In the saw there is an electronic control comprising a timer which measures the r.p.m. of the engine. During certain intervals the difference in r.p.m. is computed with respect to previous intervals and if the r.p.m. has decreased more than a predetermined value, a sensor in the electronic control emits a signal which releases an electrically controlled chain brake for stopping the chain.