Elastomeric Strut Bushings for Mower Deck Stability
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Solution Overview
Problem
Existing rotary cutting deck systems in zero radius turn mowers suffer from lateral instability due to wear in stabilization structures, transmission of vibration and shock loads through solid pivot pins, and complex assembly requirements with tight tolerances.
Innovation Solution
The use of longitudinally and laterally extending struts with elastomeric pivot connections, featuring rubber bushings that allow three-axis movement, replacing solid pivot pins to reduce wear and noise, and simplifying assembly by eliminating the need for precise alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If solid pivot pins are used to connect struts to the cutting deck and frame, then the struts can transmit propulsive force effectively, but the cutting deck becomes prone to lateral instability due to wear and the system transmits vibration and shock loads
Solution Approach 1:
The patent introduces elastomeric members (rubber bushings) as intermediary elements between the solid pivot pins and the connecting structures. These elastomeric members serve as mediators that maintain the force transmission function while eliminating the harmful effects of solid pin connections, specifically lateral instability and vibration transmission. The elastomeric members deform elastically to accommodate movement while providing damping and stability.
Solution Approach 2:
The patent changes the physical parameters of the connection system by replacing rigid solid pivot pins with compliant elastomeric members. This parameter change transforms the connection from rigid to flexible, allowing the system to maintain force transmission while gaining lateral stability through the elastomeric properties of the new materials. The elastomeric members can deform within elastic limits to accommodate operational movements.
2Device complexity
If solid pivot pins are used in the strut connections, then the structure is simple, but the system generates noise and transmits shock loads to the operator
Solution Approach 1:
The elastomeric members act as intermediary elements that insert between the solid pivot pins and the connection structures. This intermediary layer absorbs and dampens the noise and vibration generated during operation, preventing these harmful factors from being transmitted to the operator while maintaining the relatively simple overall structure of the strut connection system.
Solution Approach 2:
The patent converts the potentially harmful rigid contact and impact between solid pivot pins into beneficial elastic deformation of the elastomeric members. The shock loads and vibrations that would normally be harmful are instead absorbed and dissipated by the elastomeric material's inherent damping properties, transforming the harmful mechanical impacts into beneficial energy dissipation through elastic deformation.
3Reliability
If wide horizontal sleeves with forked mounts are used to provide lateral stabilization, then the cutting deck is stabilized, but the assembly requires tight tolerances and complex alignment
Solution Approach 1:
The patent changes the connection parameters from rigid fixed-position connections to flexible elastomeric connections. The elastomeric members can deform to accommodate variations in alignment and positioning, eliminating the need for tight manufacturing tolerances and complex alignment procedures while still providing effective lateral stabilization through their elastic properties.
Solution Approach 2:
The patent transitions from static rigid connections to dynamic elastomeric connections that can adapt their configuration during operation. The elastomeric members can deform and adjust to accommodate movement and alignment variations, providing lateral stabilization that is tolerant of manufacturing imperfections and assembly variations.
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
The solution provides improved lateral stability, reduced wear, noise reduction, and enhanced operator comfort by absorbing vibrations and shock loads, while simplifying the assembly process with a more durable and quieter strut system.
Implementation Method 1
An elastomeric member is provided in at least one of the pivot connections of each strut to minimize the transmission of vibration and shock loads from the deck to the frame
Implementation Method 2
The rubber bushings are configured to minimize wear on the struts and to laterally stabilize the cutting deck
Data Source
AI summary
A mower has a frame that supports a rotary cutting deck. A height of cut system is provided for adjusting the height of cut of the deck. In addition, two longitudinal struts and a lateral strut connect between the frame and the rear of the deck. The longitudinal struts propel the deck in forward and reverse directions while the lateral strut provides lateral stabilization to the deck to prevent excessive side-to-side motion of the deck. Each of the struts is a simple elongated rod or bar having a hub at either end that contains a rubber bushing allowing three-axis motion. Each strut is pivotally connected at each hub to corresponding portions of the frame or the deck.