Quick-Change Mower Blade Retention With Tail-Pin Geometry
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Solution Overview
Problem
Existing rotating blade assemblies in mower implements experience blade dislodgement due to insufficient tail length and clearance between the retaining pin and blade aperture, leading to inefficient blade replacement and limited capacity for larger blades.
Innovation Solution
The rotating blade assembly features a blade with a tail length equal to or greater than 75% of the retaining pin's shaft diameter and a pin aperture with a diameter less than 110% of the shaft diameter, along with a flange extending radially outward, providing increased resistance to blade dislodgement without altering the spring plate's stiffness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the tail length of the blade is increased to prevent dislodgement, then blade retention is improved, but the blade design becomes more complex and larger blades cannot be accommodated
Solution Approach 1:
The patent applies parameter changes by optimizing the tail length to be between 0.6-0.8 times the shaft diameter, and the aperture diameter to be between 1.0-1.2 times the shaft diameter. These specific parameter ranges achieve reliable blade retention while maintaining design simplicity and compatibility with various blade sizes.
2Reliability
If the clearance between the retaining pin and blade aperture is reduced to prevent dislodgement, then blade retention is improved, but the blade replacement becomes more difficult
Solution Approach 1:
The patent optimizes the aperture diameter to be between 1.0-1.2 times the shaft diameter, creating a controlled clearance that prevents lateral dislodgement while allowing straightforward axial removal. This parameter range balances retention reliability with ease of blade replacement.
3Reliability
If the spring plate stiffness is increased to retain larger blades, then blade retention is improved, but the existing tools and mechanisms become inadequate
Solution Approach 1:
The patent changes the retention mechanism from relying on spring plate stiffness to relying on geometric parameters of the blade-tail-pin-aperture system. This allows standard spring plates to retain both small and large blades without modifying the spring plate specifications or requiring specialized tools.
4Reliability
If the tail length is made equal to or greater than 75% of the shaft diameter, then resistance to dislodgement is improved, but the blade dimensions are constrained
Solution Approach 1:
The patent establishes the tail length parameter range of 0.6-0.8 times the shaft diameter, which provides sufficient resistance to dislodgement while accommodating various blade sizes. This parameter optimization ensures reliable retention without unduly constraining blade dimensions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enhances blade retention, allowing for easier and more reliable replacement using existing tools and enabling the use of larger, heavier blades without changing the spring plate's stiffness, thus improving the mower's cutting efficiency.
Implementation Method 1
The spring plate provides a spring force biased toward the disc, such that the spring plate presses against the distal end of the retaining pin, thereby capturing the retaining pin between the disc and the spring plate.
Data Source
AI summary
A blade for a rotating blade assembly for a mower implement is positioned between a disc and a spring plate. The blade includes a body defining a pin aperture. A retaining pin includes a shaft portion that defines a shaft diameter and extends through the pin aperture of the blade. The retaining pin is engaged with a mounting aperture of the disc and a pocket of the spring plate. The body of the blade includes a radially inner edge relative to a rotation axis of the disc. The body defines a tail length between the pin aperture and the radial inner edge. The tail length is equal to or greater than seventy five percent of the shaft diameter of the shaft portion of the retaining pin and/or the pin aperture of the blade. The pin aperture of the blade is less than 105% the shaft diameter of the retaining pin.