Abstract: A carburetor control system for a carburetor including a first cam and a second cam. The carburetor includes a choke valve assembly and a throttle valve assembly. The first cam is connected to the choke valve assembly. The second cam is connected to the throttle valve assembly. The second cam includes a first section and a second section. When the first cam is moved to a choke position the first section can be contacted by the first cam to latch the second cam in a start position. When the throttle valve assembly is moved to a wide open throttle position the second section can contact the first cam to hold the first cam in the choke position.

Abstract: A fuel delivery system for an internal combustion engine. The fuel delivery system includes a carburetor housing having an air passage with a throttle valve disposed therein. A choke lever is movably mounted to the carburetor housing for restricting air flow into the air passage. A fuel injection device is provided for injecting fuel into the air passage before the engine is started. Movement of the choke lever to an engaged position simultaneously opens the throttle valve, restricts air flow into the air passage and activates the fuel injection device to inject a predetermined volume of fuel into the air passage. The air-flow restriction and the predetermined volume of fuel are adjusted to compensate for changes in ambient temperature.

Abstract: A fuel delivery system for an internal combustion engine. The fuel delivery system includes a carburetor housing having an air passage with a throttle valve disposed therein. The air passage has an inlet and an outlet. The outlet is in communication with the engine. Means are provided for simultaneously opening the throttle valve, restricting air flow into the air passage and injecting a predetermined volume of fuel into the air passage before the engine is started. Other means are provided for automatically adjusting the restriction of air flow and the predetermined volume of fuel to compensate for changes in ambient temperature.

Abstract: A two-stroke, U-type uniflow engine includes a cylinder block forming parallel first and second cylinders and a common combustion chamber connecting the first and second cylinders. First and second pistons are mounted for reciprocal, linear movement within the first and second cylinders respectively. The engine also includes a crank shaft having a crank pin and a one-piece forked connecting rod connecting each of the first and second pistons to the crank pin. The connecting rod is elastically, bilaterally flexible to accommodate variations between a maximum distance between the first and second pistons and a minimum distance between the first and second pistons and is in a relaxed state half-way between the maximum distance and the minimum distance. The central wall has a slot for passage of the connecting rod therethrough and angled notches which correspond to maximum angles of the connecting rod.

Abstract: A flexible line trimmer is powered by a two-stroke internal combustion engine. The engine is scavenged in a uniflow fashion and has a scavenging cylinder and an exhaust cylinder connected by a common combustion chamber. Each cylinder has a piston turning one of two cantilevered crankshafts that are geared through adjacent counterweights having integrally formed teeth. The crankshafts extend in opposite directions for self-balancing. One crankshaft is coupled to a flywheel fan and other coupled to a starter. A fuel and air mixture is transferred to a common crankcase for the crankshafts through an intake port located on the exhaust cylinder. The piston of the scavenge cylinder is retarded with respect to the exhaust cylinder. An exhaust window opens prior to a scavenge window. The scavenge window closes after the exhaust window. The exhaust window is shortened to improve crankcase compression. The cylinders are joined in a siamese fashion, fabricated from a single piece, and skewed toward each other.

Abstract: An air cooled internal combustion engine for a hand-held power tool has a flywheel fan that is rotated within a fan housing. The bottom of the fan housing, which is perpendicular to the axis of rotation of the fan, includes an opening for an air duct. Ramps axe formed around the leading edges of the duct opening, either on a plate (metal or plastic) attached to the housing or integrally with the bottom wall, for deflecting solid particles entrained in the air away from the outlet. A relatively particle-free stream of pressurized air stream is diverted into the duct and delivered to an air intake box containing an air filter and carburetor.

Abstract: A portable work producing apparatus, such as a chain saw, has an engine cooled by air from a blower driven by the engine. The engine's carburetor is pressurized with clean air from the blower. The blower includes a centrifugal impeller mounted within a fan housing having a set of blades for creating a vacuum to draw air into the housing. The impeller has a second set of relatively low-profile blades underneath the impeller for creating a vacuum under the impeller that draws air in through holes defined through the hub of the impeller. The air drawn through the holes is supplied to the carburetor. A circular screen extends from the axis of the impeller over the holes. Small particles entrained in the air stream entering the housing tend to be carried by the predominant portion of the stream into the housing. The screen is positioned and of a size that the trajectories of more massive particles entering the housing that are not blown into the housing bounce off the screen.

Abstract: Apparatus for cutting vegetation with a rotatable head carrying a non-metallic cutting line extended into a cutting plane. As the line extension decreases from an established preset length an actuator in the head permits additional line to be extended automatically from a supply source within the head. The actuator imposes a back pressure against the line of magnitude correlated to the sensed pull tension wanting to extend the line outward of the head. After the cutting line length is extended to its restored original preset length, the actuator in response to the operational forces imposed thereon secures the cutting line against further extension until a subsequent decrease in line extension is incurred. In one embodiment an inertial drag brake is activated during the course of line feedout and is deactivated after the length of cutting line has been fully restored.

Abstract: A portable, hand-held blower/vacuum unit has a housing structure defined by an upper engine shroud removably connected to the top wall of a lower impeller housing. Disposed within the shroud is a small internal combustion engine having a vertical crankshaft which extends downwardly through a depending well section formed on the top wall of the impeller housing, the lower shaft end being drivingly connected to a centrifugal fan impeller positioned within the impeller housing and operative to force a flow of ambient air therethrough. The engine is resiliently and floatingly mounted within the shroud by a resilient support system which prevents rigid contact between the engine and the shroud or the impeller housing to thereby substantially reduce engine vibration transmitted to the housing structure, and permit deflection of the engine relative to the housing structure to lessen the possibility of engine damage caused by impeller impact from ingested objects.

Abstract: A portable, hand-held blower unit is powered by a small internal combustion engine having movable choke and throttle control elements linked to a single adjustment knob. Rotation of the knob between full throttle and full choke positions thereof simultaneously adjusts the engine's throttle and choke settings and maintains predetermined engine start and run positional relationships therebetween. The engine carburetor has mounted thereon a specially designed air intake box which substantially reduces engine air intake noise. In the normal operating position of the unit the engine drive shaft is generally vertically oriented, with the carburetor being secured to the top of the engine and the underside of the air intake box. The lower end of the drive shaft is coaxially secured to the unit's blower fan impeller which is spaced upwardly apart from a pull rope starter pulley rotatably carried by the fan impeller housing.

Abstract: A portable, hand-held blower unit is powered by a small internal combustion engine having movable choke and throttle control elements linked to a single adjustment knob. Rotation of the knob between full throttle and full choke positions thereof simultaneously adjusts the engine's throttle and choke settings and maintains predetermined engine start and run positional relationships therebetween. The engine carburetor has mounted thereon a specially designed air intake box which substantially reduces engine air intake noise. In the normal operating position of the unit the engine drive shaft is generally vertically oriented, with the carburetor being secured to the top of the engine and the underside of the air intake box. The lower end of the drive shaft is coaxially secured to the unit's blower fan impeller which is spaced upwardly apart from a pull rope starter pulley rotatably carried by the fan impeller housing.

Abstract: A portable, hand-held blower/vacuum unit has a housing structure defined by an upper engine shroud removably connected to the top wall of a lower impeller housing. Disposed within the shroud is a small internal combustion engine having a vertical crankshaft which extends downwardly through a depending well section formed on the top wall of the impeller housing, the lower shaft end being drivingly connected to a centrifugal fan impeller positioned within the impeller housing and operative to force a flow of ambient air therethrough. The engine is resiliently and floatingly mounted within the shroud by a resilient support system which prevents rigid contact between the engine and the shroud or the impeller housing to thereby substantially reduce engine vibration transmitted to the housing structure, and permit deflection of the engine relative to the housing structure to lessen the possiblity of engine damage caused by impeller impact from ingested objects.

Abstract: A compact, light weight, structurally simplified bump-feed type cutting head for a flexible line trimmer is formed from only six components--a hollow cylindrical hub having an open lower end; an annular cover member releasably securable over the lower hub end; a threaded arbor press-fitted into the hub to secure it to the trimmer drive shaft for rotation therewith; a hollow tubular release button member slidably extended through the central cover member opening and axially movable between downwardly extended and upwardly retracted positions; a line storage spool rotatable carried by the release button member within the hub; and a cylindrically coiled compression spring captively retained within the release button and biasing it toward its downwardly extended position. During high speed rotation of the hub about its axis, an outer end portion of flexible line coiled on the spool and passing outwardly through a hub side aperture is whirled through a transverse cutting plane to trim adjacent vegetation.

Abstract: A flexible line trimmer is provided with an automatic line feeding cutting head portion which utilizes a generally U-shaped, centrifugally actuated balancing arm member to maintain the free end cutting length of the line at a predetermined length during trimmer operation. The balancing arm is rotatably mounted within the head by means of a coil spring element which is installed on one of the leg portions of the balancing arm and press-fitted into a plastic pocket portion of the head to serve as a bearing for the balancing arm. The outer end of the spring-carrying leg has a transverse pigtail portion which may be selectively sized to predeterminably vary the controlled cutting length of the line. The opposite leg of the balancing arm, which is engaged by the line during trimmer operation, is received within spool flange notches when the arm is in its line locking position to prevent undesirable bending of the arm due to cutting line forces thereon.

Abstract: Apparatus for cutting vegetation with a rotatable head carrying a non-metallic cutting line extended into a cutting plane. As the line extension decreases from an established preset length an actuator in the head permits additional line to be extended automatically from a supply source within the head. The actuator imposes a back pressure against the line of magnitude correlated to the sensed pull tension wanting to extend the line outward of the head. After the cutting line length is extended to its restored original preset length, the actuator in response to the operational forces imposed thereon secures the cutting line against further extension until a subsequent decrease in line extension is incurred. In one embodiment an inertial drag brake is activated during the course of line feedout and is deactivated after the length of cutting line has been fully restored.