Blade mounting assembly

1. A blade mounting assembly for mounting a rotary blade to an arbor, the arbor defining a shoulder and a spindle, and the rotary blade defining a bore therethrough and having a right side face facing the shoulder and a left side face facing away from the shoulder, the bore having a perimeter wall that defines a perimeter shape with a keyed portion, said mounting assembly comprising:

an outer washer including;

an elongated hub configured to extend through the bore of the rotary blade, said hub defining a central bore sized to receive the spindle of the arbor extending therethrough and a locating surface arranged to contact the shoulder when the spindle extends through said central bore, said elongated hub having an outer surface that forms a perimeter shape that is shaped complementary to the perimeter shape of the bore of the rotary blade, the outer surface of the hub including a keyed portion that is configured to interlock with the keyed portion of the bore of the rotary blade when the hub is extended through the bore so that the rotary blade is rotated together with the outer washer by the arbor; and

an engagement surface arranged to contact the left side face of the blade when the hub extends through the bore of the rotary blade;

a fastener configured for fastening said outer washer to the arbor with said locating surface in contact with the shoulder; and

a biasing element configured to be disposed over said hub between the shoulder and the right side face of the blade when said hub extends through the bore of the rotary blade, the biasing element being configured to bias the rotary blade away from the shoulder such that left side face of the rotary blade is positioned in contact with the engagement surface of the outer washer;

wherein the locating surface of the hub of the outer washer is configured to space the engagement surface a fixed axial distance apart from the shoulder when the locating surface is positioned in contact with the shoulder with the spindle extending through the central bore of the hub,

wherein the fixed axial distance is greater than a thickness of the rotary blade between the left side face and the right side face such that, when the biasing element biases the left side face of the rotary blade into contact with the engagement surface, the right side face of the rotary blade is spaced apart from the shoulder.

2. The blade mounting assembly of claim 1 , wherein said biasing element is a spring washer concentrically mounted over said hub.

3. The blade mounting assembly of claim 2 , wherein said spring washer includes an outer foot aligned with said engagement surface when said spring washer is concentrically mounted over said hub.

4. The blade mounting assembly of claim 1 , wherein said fastener includes a bolt having a threaded shank configured for engaging a threaded bore in the spindle, and an enlarged head configured to bear against said outer washer when said threaded shank is tightened within the threaded bore.

5. The blade mounting assembly of claim 1 , wherein said engagement surface of said outer washer extends radially from said hub.

6. The blade mounting assembly of claim 5 , wherein said engagement surface is an annular surface.

7. The blade mounting assembly of claim 6 , wherein said biasing element includes a foot at one end contacting the shoulder and a foot at an opposite end contacting the right side face of the blade, said opposite foot being axially aligned with said annular engagement surface when said biasing element is disposed over said central hub.