Abstract: A clutch arrangement for a motor driven chain saw having a first clutch element driven by the motor shaft and a second clutch element normally engaged with the first clutch element but disengageable therefrom and a centrifugal clutch between the second clutch element and the drive sprocket for the saw chain. The second clutch element includes a spring disc and is axially yieldable between clutch engaged and clutch disengaged positions. A lever is provided moveable for disengaging the clutch elements and a brake member connected to the lever is operable for braking the drive sprocket when the clutch elements are disengaged.

Abstract: A method of producing cutting teeth for a chain saw each of which has a tooth roof and a base body cranked relative to the tooth roof along a substantially sharp edge. The method includes using as starting material a flat band which at least on one flat side of the flat band has a ridge-shaped projection extending in the longitudinal direction of the flat band. The method further includes cutting the band transverse to its longitudinal axis into sections so that each section has an overall size just sufficient for the formation of a cutting tooth to be formed, while the ridge-shaped projection divides each section into a shorter end portion and a longer end portion. The shorter end portion is bent to form the tooth roof, and the longer end portion is provided with a crank relative to the tooth roof.

Abstract: A control device for the engine of an engine driven saw having a carburetor with a normally closed fuel control or throttle valve and a normally open starting or choke valve. The device includes a selector member which has a "stop" position in which the engine ignition is disabled and an "operating" position in which the throttle valve is freely adjustable. The selector member also has a "warm start" position and a "cold start" position with the throttle valve being held in a position of minimum opening thereby in each position while the starting valve is held closed by the selector member only in the "cold start" position of the selector member.

Abstract: A guiding rail arresting device for motor driven hand saws, especially motor chain saws, in which a sword-shaped guiding rail provided with a guiding groove extending in the longitudinal direction of the guiding rail is adapted to be clamped transverse to the plane of said rail against an abutment having associated therewith a counter guiding member for cooperation with the flanks of the guiding groove. The counter guiding member for at least one of the groove flanks is formed by a supporting element adapted when clamping the rail against the abutment automatically to be clamped against the groove flank.

Abstract: A cutting saw chain having cutting tooth links distributed therealong. Each cutting tooth link having a portion at one end upstanding therefrom and twisted out of the plane of the link to form a cutting edge. The links on opposite sides of the chain have the upstanding portions twisted in opposite directions. Each cutting tooth link at the other end has a portion upstanding in the plane of the link and forming depth limiting means. A link in advance of each cutting tooth link also has an upstanding part forming a depth limiter for the following cutting tooth link.

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.

Abstract: A clutch arrangement for a motor driven chain saw having a first clutch element driven by the motor shaft and a second clutch element normally engaged with the first clutch element but disengageable therefrom and a centrifugal clutch between the second clutch element and the drive sprocket for the saw chain. The second clutch element includes a spring disc and is axially yieldable between clutch engaged and clutch disengaged positions. A lever is provided moveable for disengaging the clutch elements and a brake member connected to the lever is operable for braking the drive sprocket when the clutch elements are disengaged.

Abstract: A portable motor chain saw with a guiding rail structure which on at least a portion of its circumferential surface on which the saw chain is slidably guided has a semicircular head by which the chain is deviated while a reinforcing layer of Stellite is applied on the region of the deviating portion of the guiding rail structure, the Stellite together with the adjacent guiding rail portion being tempered.

Abstract: A hood for a rotary tool, such as a grinding wheel on a saw or the like, in which the hood is rotatable about the axis of the tool and is spring clamped in adjusted rotary positions. A lever pivoted to the hood has a neutral position in which the clamp is effective for clamping the hood while the lever is moveable in either direction from the neutral position thereof for unclamping the hood while simultaneously adjusting the hood in the same direction.

Abstract: A motor chain saw with a driving sprocket wheel adapted to be driven by a motor through the intervention of a centrifugal clutch, or the like. A safety clutch is arranged in the driving connection between the motor shaft and the driving sprocket and disengageable by a release mechanism. The safety clutch includes at least one disengageable follower member for interconnecting the two pertaining clutch members while being coaxially arranged with the centrifugal clutch and being located adjacent thereto. The safety clutch is arranged on that side of said centrifugal clutch which faces toward the driving sprocket while being located in the driving connection between the centrifugal clutch and the driving sprocket.

Abstract: A motor chain saw in which serially arranged clutches are interposed between the motor output shaft and the chain of the saw. The clutches include a centrifugal clutch and a mechanically controlled clutch. The mechanically controlled clutch has at least one drive element having an engaged position and a disengaged position and is acted on by centrifugal force urging it toward the position which it occupies. A spring urges the device element toward engaged position with a force less than the centrifugal force which acts on the drive element above a certain speed. The mechanically controlled clutch includes at least one control operable to move the drive element in at least disengaging direction during rotation of the clutch.