Aktiebolaget Electrolux

Other

Husqvarna Ab

Dag H Edlund

Par B Martinsson

Thomas Engman

An arrangement for attaching a bar of a hand-held motor driven tool, such as a chain saw, to a body of the tool includes at least one first engagement device, a cover portion adapted to bear against a bar such that the bar is arranged between the cover portion and the body, and at least one second engagement device is adapted to engage the first engagement device for securing a bar between the cover portion and the body. The second engagement device is arranged to move a first distance along the first engagement device in a direction of the rotation axis of the second engagement device for securing a bar between the cover portion and the body. The second engagement device is captively attached to a spring biasing member having an undistorted position and a distorted position.

Attaching arrangement for hand-held motor-driven tools

An automatic valve for reducing compression in order to facilitate starting of a two-stroke internal combustion engine includes a movable valve (,) adapted to control a gas flow through an opening (,) provided in a wall of the combustion chamber of the engine. A spring (,) is adapted to move the movable valve (,) to an open position, and a drive actuated by an underpressure is adapted to move the movable valve (,) to a closed position against the action of the spring (,). The driver includes a cylinder (,), a piston (,) movable in the cylinder (,) and connected to the movable valve (,), and a conduit (,) connecting the cylinder (,) to a source of underpressure. A one-way valve (,) is provided in the conduit (,) for allowing an air flow in a direction a way from the (,) only, and a leak passage (,) is adapted to allow a small flow of air into the (,) for facilitating the opening of the movable valve (,) when operation of the engine has been stopped.

Automatic decompression valve for an internal combustion engine

The present invention relates to a compression release valve (10;10';10';10'') for a combustion piston engine, said valve including a housing (12;12';12'') with a chamber (20;20';20'') having a passage (24;24';24'') in direct connection with the combustion chamber (22;22') of the engine and outlet means (26;26';26'') connected to the atmosphere or a space separated from the combustion chamber (22;22'). The compression release valve according to the present invention is characterized by being fully automatic. The function of the compression release valve is based on the fact that the valve includes elements of material having different coefficients of thermal expansion.

Compression release valve for a combustion engine

An arrangement in an internal combustion engine comprises a membrane carbureter (10) having a fuel chamber (12) provided with a movable membrane (11) cooperating with a valve (17) for controlling the fuel supply to said fuel chamber. The air inlet of the carbureter is connected to a filter housing (31) provided with an air filter (32) for cleaning the inlet air, and a pressure chamber (13) is disposed adjacent said membrane and connected to said filter housing to control the fuel supply in relation to the pressure drop across said air filter (32). According to the invention, the membrane (11) is arranged in parallel with a wall (33) of the filter housing, and said wall is disposed adjacent to the pressure chamber (13) and provided with an opening (34) via which said pressure chamber communicates with the interior of said filter housing.

Arrangement in an internal combustion engine

Vibration isolator

The starting of an i.c. engine usually takes place by carrying out the necessary number of starting attempts with the carburetor choked in order to obtain an ignition. After that, the choke valve (15,23,24) is opened and the engine can be started by making more starting attempts. Thus, the engine does not continue to run when the choke is on. In order to simplify the starting procedure of e.g. a chain saw, the carburetor can be provided with an elastic choke valve. The elastic valve makes the engine start even though the choke valve is closed as the choke valve will yield to the air stream (FIG. 1) and furnish fuel air mixture to the engine. With the engine running, the choke valve can then be opened.

Automatic choke

The invention relates to a centrifugal clutch with coupling jaws and pressure spring. Usually tension springs are used for the type of couplings which have three jaws. Tension springs have a weak point in their attachment lugs that are in most cases exposed to harder stress than the rest of the spring body. Likewise, the lugs get often indication of fracture during the manufacture of owing to wear. The present proposal aims at getting a higher security against spring breaks by using pressure springs. It is characterized by hole spaces (18,19,29) in jaws (13) and spoke plates (14,15) and by supporting bridges (23) between the spoke plates.

Centrifugal clutch

When moving the guide bar on a chain saw in order to adjust the chain tension, the following procedure is applied. Through the guide bar runs a shaft (19) having a slot for a screw driver as well as a shape of a cog-wheel (18) on the inside of the guide bar. The hole in the guide bar is the ordinary hole for a tension pin. The cover (11) above the clutch also keeps the guide bar in place and has an oval opening (23) providing accessibility to the above shaft in all its positions. Inside the guide bar, in the saw body, there is a suitable oblong cavity (16) to make room for the cog-wheel part of the shaft. That cavity has on its lower edge the form of a straight toothed section (17) adapted to the cog-wheel part.

Tension device for a chain in a chain saw

A chain tension arrangement of a chain saw having a freely displaceable pin (19) in the saw body introduced into suitable hole (21) in the sword (15) and a tension screw (24) in the cover (10) which covers the centrifugal clutch and is included into the attachment of the sword. For the chain tension moment no presetting of the chain tightening arrangement is required. Owing to the shape of the parts those ones get engaged with each other when fitting the cover. Then the chain tightening is effected with a set screw (25) in the cover by means of a simple hand grip and, after that, the sword attachment is tightened.

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Huskvarna, Sweden

Dag H Edlund