摘要:
A valve drive having a rocker arm mounted on a cylinder head is provided. One end of the rocker arm is actuated by a push rod to actuate a valve stem of a poppet valve that engages the other end of the rocker arm, which is pivotably held between its ends on a support pin that extends into the cylinder head, with a spherical mounting being provided between the support pin and the rocker arm. Provided on that side of the rocker arm remote from the cylinder head is a bolt head for adjusting the bearing spacing between the rocker arm and the cylinder head for adjusting valve play. To prevent unintended adjustment of the bolt head, the latter cooperates with a rotation preventing element that has an arresting portion that engages the bolt head, and a support portion that conveys the adjustment moment away.
摘要:
A cam drive is provided for a valve control of a mixture-lubricated internal combustion engine that has a cylinder, and a cylinder head in which is disposed a poppet valve which is actuated by a pivotable rocker arm. Mounted in a cam chamber is a control cam that is driven by the crankshaft of the engine and on the cam path of which rests a drag lever that transfers the cam lift to the rocker arm. To achieve a reliable mixture lubrication, a flow guidance element is disposed in the annular chamber between the peripheral wall of the cam chamber and the maximum diameter of the path of a cam nose. The flow guidance element is provided with a flow edge that is disposed adjacent to the drag lever in the vicinity of the path diameter of the cam nose.
摘要:
A portable handheld work apparatus such as a motor-driven chain saw includes a housing (6) of a drive unit (2). The following are mounted in the housing (6): an internal combustion engine (3), a carburetor (4) for fuel metering and an air filter (5) as well as a fuel tank (8). The air filter (5) is mounted ahead of the carburetor in the flow direction of the fresh air flow. A largest possible filter action is obtained with a compact configuration in that a housing (10) of the air filter (5) lies at least partially in a space between the carburetor (4) and the fuel tank (8).
摘要:
A hand-held working tool has a housing and an internal combustion engine arranged in the housing and comprising a crankshaft and an air filter. A tool is driven by the crankshaft of the internal combustion engine. A fan housing is attached to the engine housing and has an air inlet. A fan wheel is arranged in the fan housing and is driven by the crankshaft of the internal combustion engine to supply cooling air, sucked in through the air inlet, to the internal combustion engine. The fan housing has a bottom extending radially to the crankshaft. The bottom and a side of the fan wheel facing the bottom define a chamber in the fan housing. The bottom has a combustion air outlet. A combustion air channel is connected to the combustion air outlet and to the air filter. The combustion air outlet is axially supplying combustion air from the chamber through the combustion air channel into the air filter of internal combustion engine. The fan housing has a channel wall having a bottom portion connected to the face of the bottom remote from the fan wheel and covering the bottom partially to form a double-walled bottom. The end face portion of the combustion air channel is defined by the bottom and the bottom portion of the channel wall. In an alternative embodiment the combustion air channel is provided in a hollow beam of a support that supports the drive unit of the working tool.
摘要:
A two-cycle engine in a portable, manually-guided implement, such as a power chain saw, a cut-off machine, a brush cutter, or the like, is provided. The cylinder has a combustion chamber that is delimited by a reciprocating piston that via a connecting rod drives a crankshaft that is mounted in a crankcase so as to be rotatable about a crankshaft axis. The cylinder has an outlet for conveying exhaust gases out of the combustion chamber, with the outlet having an axis of the channel thereof. The cylinder also has an inlet for supplying a fuel/air mixture to the crankcase. By means of at least two transfer channels, the fuel/air mixture is conveyed out of the crankcase and into the combustion chamber, with the transfer channels being disposed symmetrically relative to the axis of the channel of the outlet. When viewed in the direction of the longitudinal axis of the cylinder, the axis of the channel of the outlet is disposed at an angle of less than 90° relative to the longitudinal central axis of the crankshaft.
摘要:
A cam drive is provided for a valve-controlled mixture-lubricated internal combustion engine having a cylinder in which is formed a combustion chamber that is delimited by the cylinder wall, a piston and a cylinder head. Disposed in the cylinder head are poppet valves, the respective valve shafts of which are driven via a pivotable rocker arm from a valve control that includes a control cam on the surface of which rests a contact lever that transfers cam lift to one end of the rocker arm. To ensure good lubrication of the cam drive even at high speeds, the control cam is rotatably mounted in the vicinity of the cylinder wall, in which is formed a through-bore. The first open end of the through-bore is disposed in the cylinder bore at the level of the piston in its lower dead center position, while the second open end opens into the cam chamber in the vicinity of the control cam.
摘要:
A valve drive mechanism is provided for an internal combustion engine, especially a four-stroke engine in a power chain saw. The implement housing is spanned by a front handle, the tubular grip of which is adjacent to the cylinder head of the engine and extends from one longitudinal side of the implement to the other longitudinal side thereof. A rocker arm of a valve control is pivotably mounted on the cylinder head between the ends of the rocker arm, with the rocker arm being pivotable about a pivot axis disposed transverse to the rocker arm. Push rods of a control mechanism engage one end of the rocker arm to actuate a poppet valve, on the valve stem of which the other end of the rocker arm acts. To be able to guide the tubular grip close to the center of gravity of the implement, the longitudinal axis of the rocker arm is disposed approximately parallel to the adjacent portion of the tubular grip.
摘要:
The invention relates to a portable handheld work apparatus including a chain saw, a vacuum/blower apparatus or the like. The work apparatus has a handle (2) for carrying and guiding the work apparatus (1). Thumb supports (4, 5) are provided on both sides with respect to the longitudinal axis (3) of the handle (2).
摘要:
A diaphragm carburetor is provided for an internal combustion engine that operates with scavenging air, especially a two-cycle engine in a manually-guided implement. The carburetor has an intake channel portion in which is disposed a butterfly valve that is rotatably held via a shaft and in the vicinity of which fuel-supplying channels open into the intake channel portion. The channels are supplied from a fuel-filled regulating chamber that is formed on a longitudinal side of the intake channel portion in the carburetor housing and is separated by a regulating diaphragm from a compensation chamber. The carburetor has at least one air channel that supplies additional combustion air and that has an air valve that is rotatably held via a shaft. The butterfly valve and the air valve can be brought from a closed position, in which the butterfly valve or the air valve only insignificantly influence the flow in the intake channel portion or in the air channel, into a closed position in which the intake channel portion or the air channel are substantially closed off in an airtight manner, and in an opening direction from the closed position into the opened position. The air valve is coupled to the butterfly valve via a coupling mechanism that compensates for axial and radial tolerances and includes a spring.
摘要:
The invention relates to a vibration damper between a housing (4), which holds an internal combustion engine, and a handle (3) fixed on the housing (4). The handle (3) is for holding and guiding the motor-driven chain saw (2) during use thereof. The vibration damper (1) is a coil spring (5) which is fixed at a first end (10) thereof with an attachment element (7) to the handle (3) and, at a second end (20), the coil spring is fixed with a further attachment element (30) to the housing. A part turn of the end (10, 20) of the coil spring (5) is held form-tightly to the attachment element (7, 30) in the direction of its longitudinal center axis (25). To provide a torsion-free assembly of the coil spring, it is provided that the coil spring (5) can be assembled from one of its ends (20) between the handle (3) and the housing (4) and be secured at least at one of its ends (20) to the attachment element (30) against a rotational movement in the peripheral direction.