US 5,271,212 AGranted

Lawnmower blade with yieldable opposite outer cutting sections

OwnerRay S. Andersoninventor

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Abstract

A lawnmower blade includes a center blade section having an opening for mounting and fastening the blade to the lower end of a mower drive shaft and a pair of opposite outer blade sections containing cutting edges. The outer blade sections are substantially equal in length to one another. Also, the blade includes a pair of assemblies defining yieldable articulating joints attaching one end portion of each outer blade section to one of the opposite end portions of the center blade section such that each outer blade section can both pivot upwardly and rotate backwardly relative to the forward direction of blade rotation and to the respective one opposite end portion of the center blade section so as to yield upon striking an object and thereby prevent damage to the engine crankshaft or the cutting edges. The outer blade sections are capable of restoring to straightened longitudinal alignment with the center blade section, after passing the object, due to response to centrifugal force imposed on the outer blade sections by their rotation with the center blade section.

Claims17

Dependent claims

A lawnmower blade, comprising:

(a) a center blade section having a pair of opposite end portions and means for mounting said blade to a lower end of a mower drive shaft;
(b) a pair of opposite outer blade sections each having a cutting edge;
and
(c) a pair of yieldable articulating joints each attaching one end portion of each of said outer blade sections to one of said opposite end portions of said center blade section such that each of said outer blade sections can both pivot upwardly and rotate backwardly relative to a forward direction of blade rotation and to a respective one of said opposite end portions of said center blade section so as to yield upon striking an object and thereby prevent damage to the mower drive shaft and said cutting edges on said yielding outer blade sections;
(d) each of said yieldable articulating joints including
(i) means for pivotally connecting one of said opposite end portions of said center blade section with said one end portion of one of said outer blade sections such that said one end portion of said one outer blade section is disposed below said one opposite end portion of said center blade section, and
(ii) means mounted to said connecting means for biasing said one end portion of said one outer blade section and said one opposite end portion of said center blade section toward one another, said biasing means being yieldable to permit said one end portion of said one outer blade section to pivot away from said one opposite ends of said outer blade section upon said outer blade section striking an object.

4 more elements

A lawnmower blade, comprising:

(a) a center blade section having a pair of opposite end portions and means for mounting said blade to a lower end of a mower drive shaft;
(b) a pair of opposite outer blade sections each having a cutting edge, each of said outer blade sections being substantially equal in length to one another;
and
(c) a pair of yieldable articulating joints attaching one end portion of each of said outer blade sections to one of said opposite end portions of said center blade section such that both of said outer blade sections are yieldably retained in straightened longitudinal alignment with said center blade section and can pivot upwardly and rotate backwardly relative to a forward direction of blade rotation and to respective ones of said opposite end portions of said center blade section so as to yield upon striking an object and thereby prevent damage to the mower drive shaft and said cutting edges on said yielding outer blade sections;
(d) each of said yieldable articulating joints including
(i) a fastener pivotally connecting one of said opposite end portions of said center blade section with said one end portion of one of said outer blade sections such that said one end portion of said one outer blade section is disposed below said one opposite end portion of said center blade section, and
(ii) means mounted to said fastener for biasing said one end portion of said one outer blade section and said one another, said biasing means being yieldable to permit said one end portion of said one outer blade section to pivot away from said one opposite end portions of said center blade section upon said outer blade section striking an object.

4 more elements

A lawnmower blade, comprising:

(a) a center blade section having a pair of opposite end portions and means for mounting said blade to a lower end of a mower drive shaft;
(b) a pair of opposite outer blade sections each having a cutting edge, each of said outer blade sections being substantially equal in length to one another;
and
(c) a pair of yieldable articulating joints attaching one end portion of each of said outer blade sections to one of said opposite end portions of said center blade section such that both of said outer blade sections are yieldably retained in straightened longitudinal alignment with said center blade section and can pivot upwardly and rotate backwardly relative to a forward direction of blade rotation and to respective ones of said opposite end portions of said center blade section so as to yield upon striking an object and thereby prevent damage to the mower drive shaft and said cutting edges on said yielding outer blade sections, said outer blade sections being capable of restoring to said longitudinal alignment with said center blade section, after passing the object, due to response to centrifugal force imposed on said outer blade sections by rotation thereof with said center blade section;
(d) each of said yieldable articulating joints including
(i) a fastener pivotally connecting one of said opposite end portions of said center blade section with said one end portion of one of said outer blade sections such that said one end portion of said one outer blade section is disposed below said one opposite end portion of said center blade section, and
(ii) means mounted to said fastener for biasing said one end portion of said one outer blade section and said one opposite end portion of said center blade section toward one another, said biasing means being yieldable to permit said one end portion of said one outer blade section to pivot away from said one opposite end portions of said center blade section upon said outer blade section striking an object.

4 more elements

Dependencies are inferred from the claim text.