Abstract: The invention is relative to an ignition unit for internal combustion engines that comprises a primary circuit with a first switch for a primary winding for generating inductions in a secondary winding of a secondary circuit with a starter gap and that comprises a load circuit with the primary winding and comprises a second switch for a load.

Abstract: In order to provide a four-stroke internal combustion engine (100) having a control chamber (16) and a cylinder (14), provided with at least one intake valve (12) and at least one exhaust valve, which has a crankshaft chamber (22) formed by a crankcase (26), in which a connecting rod (24) connected to the reciprocating piston (18) drives a mounted crankshaft (28), having an ignition device and having a supply device (30) for an air-fuel mixture, which is connected on one side via a connection line (32) to the control chamber (16) and on the other side in the flow direction (54) of the air-fuel mixture to the piston chamber (20) via a throttle device (34) positioned in a mixture intake port (36) and via a mixture supply line (38), which is connected via a non-return valve (40a) to the crankshaft chamber (22), and having an overflow channel (44) between the crankshaft chamber (22) and control chamber (16), in which a camshaft (46) is positioned for controlling the intake and exhaust valves (10, 12), which allow

Abstract: The invention relates to a device for braking a motor shaft, such as a motor shaft of a chain saw, with a brake band that at least partially surrounds an area of the shaft and with at least one guide component that cooperates with the brake band and holds it in its axial position. The brake band comprises at least one projection formed in one piece with the brake band.

Abstract: With a method for controlling the fuel supply to an internal combustion engine, in particular to a two-stroke motor, a parameter (K) of the machine, which is influenced by the fuel supply in a delayed manner, is tuned to a predetermined desired value (SW) by switching on and cutting off the fuel supply. The hysteresis is largely compensated in that an upper and/or lower threshhold value (OS,US) is allocated to the desired value (SW) of the parameter (K), that the parameter (K) is continuously measured, and that the fuel supply is cut off when the measured parameter (K) crosses the lower and/or upper threshhold value from below to above, and that the fuel supply is switched on when the measured parameter (K) crosses the upper and/or lower threshhold value (OS,US) from above to below.

Abstract: In order to provide a hand-held machine tool (100), especially a motor-driven chain saw, with a combustion engine drive (116) and a generator (102) for supplying voltage to electrical consumers, to which external electrical consumers can be connected in a simple fashion, it is proposed that the generator (102) has a connection for attachments (104) for external consumers.

Abstract: With a method for controlling the fuel supply to an internal combustion engine, in particular to a two-stroke motor, a parameter (K) of the machine, which is influenced by the fuel supply in a delayed manner, is tuned to a predetermined desired value (SW) by switching on and cutting off the fuel supply. The hysteresis is largely compensated in that an upper and/or lower threshhold value (OS,US) is allocated to the desired value (SW) of the parameter (K), that the parameter (K) is continuously measured, and that the fuel supply is cut off when the measured parameter (K) crosses the lower and/or upper threshhold value from below to above, and that the fuel supply is switched on when the measured parameter (K) crosses the upper and/or lower threshhold value (OS,US) from above to below.

Abstract: The invention aims to provide a compact four-stroke engine with rotary valve control and petroil lubrication which has a simplified construction and allows the engine to be used in any position as a result of an improved lubrication system. To this end, the carburetor is directly connected to the inlet opening and the rotary valve is configured in such a way that in a first position it connects the carburetor to the combustion chamber, in a second position it connects the carburetor to the cylinder chamber/crankcase via the overflow conduit and in a third position it connect the cylinder chamber/crankcase to the combustion chamber via the overflow conduit and the combustion chamber to the outlet opening via the conduit. Said rotary valve is in continuous motion during the operation of the combustion engine and the first, second and third positions only occur at corresponding defined moments.

Abstract: The invention pertains to a handheld implement, in particular a portable chainsaw (100), with a handle housing part (12) that contains at least one carrying handle (10), and with at least one motor housing part (16) that carries a drive unit (14) and is connected to the handle housing part (12) by means of an antivibration system that consists of at least one vibration-reducing reducing element (18). The invention proposes an antivibration system of this type, in which the above-mentioned problems are solved due to the fact that an exchange of the vibration-reducing elements can be eliminated, wherein the antivibration system is still able to fulfill the individual requirements of the operator and the machine. This is achieved due to the fact that the at least one vibration-reducing element (18) is realized such that it can be adjusted with the aid of a tool or without requiring a tool.

Abstract: In order to create a compact four-cycle internal combustion engine with mixture lubrication comprising a cylinder which is closed on top by a cylinder head and which changes below into a crankcase, in the cylinder a piston moving up and down, in the cylinder head an intake port with an admission valve and an exhaust conduit with an exhaust valve, a carburetor for forming an oil-fuel-air mixture lubricating the engine, as well as means by which a mixture is transported within each engine cycle from the carburetor into the crank chamber closed by the crankcase and from the crank chamber into the intake port, engine which is constructed in a simple way and which is characterized by a good charging behavior, it is proposed that the carburetor is connected outside the crank chamber with the intake port.

Abstract: A tank cap has an upper longish handle portion engageable by a user's hand to open and close the cap relative to the tank. The handle also has, on each of its two sides, an indentation into which a screwdriver or the like can be inserted to aid in rotating the cap in the opening direction, the indentation being shaped so that if the inserted screwdriver is moved in the direction corresponding to closing of the cap the screwdriver will be cammed out of the indentation without over-tightening the cap in the closing direction.

Abstract: The invention relates to a two-stroke motor with a fresh-gas supply (preferably with oil-in-gasoline lubrication), with a motor housing in which a crank chamber with an inlet opening and a cylinder chamber with an outlet opening are formed, with a crank drive in the crank chamber and with a piston in the cylinder chamber that are connected to one another by a connecting rod, with at least one overflow conduit, with a carburetor comprising a carburetor chamber with a fresh-air entrance opening, a fuel entrance opening and a mixture exit opening as well as comprising a throttle flap that can move in a regulatable manner, with an inlet conduit in order to connect the mixed outlet opening of the carburetor chamber to the inlet opening of the crank chamber, and with a fresh-gas conduit that empties through an opening into the overflow conduit in order to supply fresh gas to the overflow conduit.

Abstract: In order to provide a hand-guided machine, which is partially or completely used at low ambient temperatures, with a heating arrangement of the handles, comprising an AC source, an analysis electronic system, at least one temperature sensor connected to the analysis electronic system and at least one electrical heating element supplied with power from the AC source, with which heating of handles of hand-guided machines is possible and which avoids the disadvantages of known handle heaters and particularly relieves the operator in his work activity as well as providing an ergonomically favorable working environment, so that work accidents and occupational illnesses are avoided, it is suggested that the output of the at least one electrical heating element be switched and regulated by an electronic component, controlled by the analysis electronic system, in the form of transistors, IGBTs, GTOs, thyristors, or TRIACs.

Abstract: This invention relates to a motor intake chamber, especially for a chain saw, with a novel opening for removing impurities that may be deposited on an air filter from the intake chamber. The intake chamber also includes a flap closing the opening for sound damping, which flap is closed during motor load operation.

Abstract: For an internal combustion engine carburetor (10) having a throttle valve (14) and a choke (22), the throttle valve (14) and the choke (22) can be brought in dependence on each other to different sets of predetermined operating positions which are appropriate respectively for the operating of the engine at no-load, for a cold start, and for a warm start, with a safe and definite adjustment being achieved in that the switch (19) is placed directly on the carburetor (10) and is connected with the choke (22) and in that the choke (22) and the throttle valve (14) are coupled with each other over mechanical couplings (16, . . . 21) with the switch (19) having a different position for each set of throttle valve and choke operating positions.

Abstract: To limit the penetration of the outer end of a chain saw into a material being cut by the saw, the chain carrying rail of the saw has a number of uniformly sized holes located at different points along its length into any selected one of which holes a limiting means can be placed, with the limiting means including two rotatable wheels located on opposite sides of the rail.

Abstract: In order to design a motor chain saw with a chain brake device releasable as a back kick brake and as a coasting brake comprising a tension lever (2), movable with respect to the housing of the motor chain saw, which can be moved between a brake position (B) and a ready position (b), a release lever (19) which can take up a coasting brake position (A) and a disengaging position (f), in combination with a supplementary brake device known as a coasting brake, it is proposed that the tension lever (2) is placed linearly slidingly movable with respect to the housing of the motor chain saw and that the release lever (1) is placed slidingly movable with respect to the tension lever (2), whereby both axles of the sliding movement are parallel to each other.

Abstract: A chain medium pump (20) for a motor chain saw (10) is made disconnectable in a simple manner, the chain medium pump (20) sucking the chain medium over a suction pipe (29) from a tank (22) and delivering it over a pressure pipe (27) to a sawing device (12) of the motor chain saw (10), by the fact that, for disconnecting the supply of the sawing device (12) with the chain medium, there exist controllable means (23-26) with which the pressure pipe (27) is interrupted, the chain medium pump (20) being running, and simultaneously the chain medium delivered by the chain medium pump (20) can be returned into the suction pipe (29).

Abstract: A power chain saw with a drive motor arranged in a housing drives a saw chain circulating on a saw guide, wherein the saw guide is held clamped by one end transversely to its surface plane between the housing and a tightening element, and for tightening the saw chain can be displaced in the longitudinal direction L when the tightening element is detached. The power chain saw also includes detent plates arranged between the saw guide and the housing and/or between the saw guide and the tightening element, which permit the displacement of the saw guide in the tightening direction, but block it in the loosening direction of the chain. The tightening element can be embodied as chain wheel protector.

Abstract: The invention relates to a case seal (6) for cross-divided crank cases, comprising an upper section (1) and a lower shell (2) (see figure). Both halves of the crank case have bearing seats (3, 4) for bearing (5) a shaft. The inventive case seal (6) is characterized in that it is configured as a single-piece elastic shaped part which can be placed on one half of a crank case along the sealing surfaces (7, 8) and the bearing seats (3, 4). Preferably, the case seal also consists of a second elastic shaped part (11) which can be inserted into the bearing seat (3) of the second half (1) of the crank case that is not provided with the first sealing part (6).

Abstract: In an engine driven hand-operated tool such as a chain saw, hedge trimmer, drill hammer and the like, cooling fluid for the engine downstream of the engine, so as to have been heated by the engine, is moved through a hollow handle of the tool to heat the handle.