ENGINE

BACKGROUND OF THE INVENTION

1. Field of Invention

The present invention relates generally to small internal combustion engines and in particular to a method and apparatus to facilitate starting a combustion engine. 2. Description of Related Art

Small internal combustion engines are used on a variety of tools, including lawn mowers, weed trimmers, outboard motors, snow blowers, chainsaws and the like. It is common to manually start the engine with a starter pullcord system. Problems with this system can arise when a motor is cold or if the spark plug is dirty. Some users are not physically capable of pulling the pullcord with sufficient force and speed to start the engine.

SUMMARY OF THE INVENTION

According to a first embodiment of the present invention there is disclosed a quick-start chainsaw comprising a chainsaw having a crankshaft extending along an axis between first and second ends, a quick-start key engagement bore extending into the crankshaft along the axis from the second end adapted to engage with and be rotated by a key; and wherein the quick-start chainsaw includes a casing with a hole therethrough aligned with the axis providing access to the quick-start key engagement bore therethrough.

The quick-start key engagement bore may be formed with an internal surface selected to engage with the key. The hole may be sized to receive the key therethrough. The second end of the crankshaft may be located within the hole. The internal surface may be formed in a shape selected from a group of hexagonal, square or star. The key may be formed with an external surface formed in a shape corresponding to the internal surface. The quick-start chainsaw may further comprise a cover adapted to close the hole.

According to a further embodiment of the present invention there is disclosed a method for starting a quick-start chainsaw comprising securing a key to a portable drill, locating the key within a hole aligned along an axis with a crankshaft extending along the axis in a chainsaw casing, connecting the key within a quick-start key engagement bore extending along the axis into a second end of the crankshaft; and rotating the key within the quick-start key engagement bore around the axis with the portable drill thereby rotating the crankshaft and starting a combustion engine.

According to a further embodiment of the present invention there is disclosed a quick-start chainsaw kit comprising a key rotatable by a portable drill, a chainsaw having a crankshaft extending along an axis between first and second ends wherein the crankshaft includes a quick-start engagement bore extending therein along the axis from the second end adapted to engage with and be rotated by the key; and a casing with a hole therethrough aligned with the axis providing access to the quick-start engagement bore therethrough.

Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures. BRIEF DESCRIPTION OF THE DRAWINGS

In drawings which illustrate embodiments of the invention wherein similar characters of reference denote corresponding parts in each view,

Figure 1 is a side view of a prior art crankshaft.

Figure 2 is a perspective view of a chainsaw having a crankshaft with an adapted second half shaft according to a first embodiment of the present invention, with a portable hand drill.

Figure 3 is a side view of the adapted second half shaft of Figure 2.

Figure 4 is an end view of adapted second half shaft of Figure 2. Figure 5 is a cross-sectional view of adapted second half shaft taken along the line 5-5 of Figure 2.

DETAILED DESCRIPTION

Referring to Figure 2, an apparatus for adapting a crankshaft of an internal combustion engine to facilitate engine start according to a first embodiment of the invention is shown generally at 30. The apparatus 30 is connected to a standard crankshaft, as will be described further below, within a chainsaw 8.

Turning now to Figure 1 , a prior art crankshaft is shown generally at 10. The crankshaft extends along an axis 100 between first and second ends, 12 and 14, respectively, and includes a first half shaft 16 proximate to the first end 12 and a second half shaft 18 proximate to the second end 14. The first and second half shafts, 16 and 18, respectively, are joined with a pair of counterweights 20 connected by a crank pin 22 therebetween, as is commonly known.

Referring to Figure 3 through 5, the apparatus 30 extends along the axis 100 between first and second ends, 32 and 34, and is formed as a half shaft 36, corresponding to the size and shape of the second half shaft 18 of the prior art crankshaft, as is commonly known. The half shaft 36 includes a key engagement bore 38 extending along the axis 100 into the second end 34 of the half shaft 36 to a bore end 40, as seen in Figures 4 and 5. The inner surface 42 of the key engagement bore 38 is adapted to engage with a standard Hex, Torx or square key or bit. The key engagement bore 38 may have a hexagonal, star-shaped ("Torx") or square cross-section, and is formed with the same profile as a standard sized Hex, Torx or square key or bit, as is commonly known, although it will be appreciated that other cross-sectional shapes, such as, by way of non-limiting example, octagonal or triangular, may be useful, as well.

Turning back to Figure 2, when installed on the crankshaft of a chainsaw 8, the apparatus 30 may be used to facilitate engine start without the use of a pullcord, as is commonly known. The apparatus 30 is accessible through a hole 50 in the chainsaw casing 2, as is commonly known. A removable protective cover (not shown) may be provided to cover the hole 50 for safety purposes when the chainsaw is in use. A portable hand drill 6 is set up with a standard Hex or Torx key bit 4, as is commonly known, selected to engage with the key engagement bore 38, as outlined above. With the drill in forward drive, the key bit 4 is engaged upon the apparatus 30, then the drill is activated, as is commonly known, thereby rapidly rotating the crankshaft 10 about the axis 100 and starting the engine, as is commonly known. Upon engine ignition, the key bit 4 is disengaged from the apparatus 30, and the protective cover placed over the hole 50.

While specific embodiments of the invention have been described and illustrated, such embodiments should be considered illustrative of the invention only and not as limiting the invention as construed in accordance with the accompanying claims.