| 摘要 |
A safety cutter blade for a rotary trimmer. The blade has a circular hub formed with a central opening for mounting the blade on the drive shaft of a rotary trimmer. An annulus is made integral with and coplanar with the hub. A plurality of cutting teeth are formed integrally with the annulus at its periphery. Each tooth is provided with a swept convex cutting edge and a straight cutting edge on opposite sides thereof. The convex cutting edges constitute a set of negative cutting edges which force severed foliage away from the center of the blade while the straight cutting edges constitute a second set of cutting edges which are adapted to cutting short grass. Each of these sets of cutting edges is adapted to be effective when they are the leading edges of the teeth of the cutter blade which is determined by the direction of rotation of the trimmer drive shaft and the position of the blade relative thereto. The blade is molded from an elastomeric material reinforced with fibers made of an organic polymer and has embedded in the elastomeric material a layer of coarse fabric made from an organic polymer. The size of the fabric is coextensive with that of the blade and the fabric is positioned to intersect the cutting edges of the teeth of the blade.
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