Abstract: A self cleaning filter for a small internal combustion engine (1) is disclosed. The filter (16, 36, 46) is generally rectangular and is located closely adjacent the air exit region of the engine's fan (2). The longitudinal axis of the filter is generally aligned with the direction of air flow. The filter can be flat (16), curved (36) or inclined towards the air flow (46). The arrangement permits a more compact configuration for the engine (1).

Abstract: A powered cutting device (1) maneuverable in the manner of a wheelbarrow, brush cutter, or stick edger by a walking operator and operable to both horizontally mow and vertically trim vegetation. The cutting device (1) includes an elongated frame (5) having handles (3), a power unit (4) supported by the frame (5), a rotatable vegetative cutter (14, 15), and a power train interconnecting the power unit (4) and the cutter (14, 15). The cutter (14, 15) is movable between a mowing position (FIG. 1) in which it rotates about a substantially vertical axis, and a trimming position (FIG. 4) in which it rotates about a substantially horizonal axis. A releasable latch arrangement maintains the cutter (14, 15) in either of the two positions. The power train includes a power directing arrangement operable to rotate the cutter (14, 15) in each of the positions.

Abstract: The present invention discloses a multiple spark transistor ignition circuit which is able to provide negligible retardation of ignition time, and/or prevent ignition with reverse rotation and/or provide an additional advanced spark and/or govern maximum engine speed and/or progressively advance the moment of ignition with increasing engine speed. The basic circuit comprises an ignition circuit of the type disclosed in U.S. Pat. No. 4,163,437 (Notaras) with a diode interposed between the primary winding and the remainder of the circuit. Circuits having a single primary winding and dual remainders or dual primary windings and single remainders are also disclosed. A governor circuit having a control transistor, a further potential divider and a control capacitor, is also disclosed.

Abstract: The present invention discloses a multiple spark transistor ignition circuit which is able to provide negligible retardation of ignition time, and/or prevent ignition with reverse rotation and/or provide an additional advanced spark and/or govern maximum engine speed and/or progessively advance the moment of ignition with increasing engine speed. The basic circuit comprises an ignition circuit of the type disclosed in U.S. Pat. No. 4,163,437 (Notaras) with a diode interposed between the primary winding and the remainder of the circuit. Circuits having a single primary winding and dual remainders or dual primary windings and single remainders are also disclosed. A governor circuit having a control transistor, a further potential divider and a control capacitor, is also disclosed.

Abstract: A protective safety cover for a power transmission chain of a chain saw power head and an attachment for the power head, having at least two fins for engagement by the cover, is provided with two grooves adapted to frictionally engage the fins to secure the cover to the attachment. The grooves are curved until the fins are located therein so that upon location of the fins in the grooves the cover is resiliently deformed to correspond to the shape of the fins thereby enhancing the frictional engagement between the fins and grooves.

Abstract: A magneto rotor assembly is disclosed in which a magnet is clamped in position between a pair of pole pieces within a cavity in a rotor. The pole pieces are provided with at least one tapered surface which engages a or the corresponding tapered surface(s) of the rotor cavity to prevent movement of the pole pieces and magnet. A fastener is also provided to hold each pole piece in engagement with the rotor cavity.

Abstract: The present invention discloses an ignition system for internal combustion engines. The ignition system is particularly applicable to such engines including a magneto.The ignition system includes a semi-conductor ignition circuit in which a first transistor has its collector-emitter conduction path connected in series with the primary winding of an ignition coil assembly. A resistor is connected between base and collector of the first transistor to permit it to conduct. A control circuit connected between the base of the first transistor and the primary winding, turns the first trnasistor off when it is desired to interrupt the primary winding current.The ignition system also includes a magneto ignition coil assembly which has a low inductance primary winding having a relatively low number of turns. The coil assemblies of the present invention are generally unsuitable for use with conventional mechanical breaker points.