Other

Andreas Stihl

Manfred Bortfeld

Dieter Wieland

Eberhard Schieber

Gunter Dietzsch

Walter Gernhard

A chain saw is disclosed having a drive motor which drives the sprocket wheel of the saw chain via a transmission stage. The sprocket wheel rotates in the same direction as the drive shaft of the drive motor and drives the saw chain in such a manner that the portion thereof traversing the lower periphery of the cutter bar moves toward the housing of the chain saw. The saw chain is braked with a braking arrangement which develops a braking moment that causes the chain saw to develop a reaction moment that opposes the kickback moment occurring as a consequence of the kickback action. In this way, the angle through which the chain saw is deflected during kickback is reduced. In addition, a compact configuration of the motor housing of the chain saw is obtained wherein the braking arrangement is kept free of dirt and chips.

Chain saw having a braking arrangement

The invention is directed to a safety arrangement for a power-driven portable tool such as a motor-driven chain saw or the like. The portable tool has a housing equipped with two handles both of which are grasped by the operator to hold and guide the tool during use thereof. One of the handles is a bail handle mounted at the forward part of the housing. The safety arrangement includes two switches associated with respective ones of the handles. The switches are operatively connected to the motor so as to cause the same to be operative only when both switches are closed. At least a portion of one of the contacts of the bail handle switch is displaceable from a first position whereat the bail handle switch is open to a second position whereat the switch contacts come into mutual contact and the bail handle switch is closed. An elastic body associated with the bail handle acts on the one contact to effect the displacement to the second position in response to pressure applied to the elastic body by the operator of the tool when grasping the bail handle.

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Leutenbach, Germany

Manfred Bortfeld