Adjustable Vibratory Feeder Elastomeric Shear Spring
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Vibratory feeders with elastomeric springs experience significant variations in spring rate due to compression creep, leading to inconsistent feed rates, which are unacceptable for commercial applications requiring precise control.
Innovation Solution
The implementation of a highly stable elastomeric shear pad system, where the elastomeric pads operate primarily in shear rather than compression, allowing for adjustable spring rate through varying compressive force, thereby stabilizing the feed rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an elastomeric spring is used in compression, then the feed rate can be adjusted, but the spring rate varies significantly over time due to compression creep
Solution Approach 1:
The patent changes the operational parameter of the elastomeric spring from compression to shear deformation. This parameter change eliminates compression creep while maintaining adjustability through controlled shear deformation of the elastomeric material between rigid plates.
Solution Approach 2:
Instead of using the elastomeric material in compression as conventionally done, the patent inverts the approach by using it in shear. The rigid plates are positioned to transmit shear forces through the elastomeric material, reversing the typical load application method.
2Force
If compressed rubber is used as a spring, then the system can provide elastic force, but the rubber creeps under continuous pressure causing performance degradation
Solution Approach 1:
The patent changes the stress state parameter from compressive to shear. The elastomeric material continues to provide elastic force through its material properties, but now operates in shear deformation which does not cause creep, thereby maintaining reliability.
Solution Approach 2:
The rigid plates act as intermediaries that transmit forces through the elastomeric material in shear rather than compression. These plates mediate the force transmission, allowing the elastomeric material to provide elastic force without experiencing compressive creep.
3Ease of operation
If the spring constant is adjusted to maintain desired flow rate, then feed rate control is achieved, but constant vigilance and adjustment are required
Solution Approach 1:
The patent creates a dynamically adjustable system where the spring constant can be modified by changing the pre-load on the elastomeric shear pads. This allows feed rate control without requiring frequent adjustments, as the system maintains stable performance after initial setup.
Solution Approach 2:
The elastomeric shear pad system is self-regulating in terms of stability. Once adjusted to the desired spring constant, the system automatically maintains consistent performance without requiring operator intervention for constant vigilance, as the shear-based mechanism inherently resists creep.
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 achieves less than 3% variance in feed rate over a 40-hour period, ensuring consistent performance and meeting commercial stability requirements.
Implementation Method 1
a first elastomeric shear pad extending generally parallel to the primary excitation plane of the moving mass; a second elastomeric shear pad extending generally parallel to the primary excitation plane of the moving mass
Implementation Method 2
The elastomer used in the first and second pads is, itself, highly stable. Tests on a feeder employing the elastomeric spring of the present invention showed less than 3% variance over a 40 hour period of operation.
Implementation Method 3
means to adjust a compressive force exerted by the first and second elastomeric pads on the support for the moving mass to vary a spring rate of the first and second pads
Data Source
AI summary
The tie bar supporting a feed tray (moving mass) is attached to the reaction mass using one leaf spring and one elastomeric spring. The elastomeric spring comprises first and second elastomeric pads which sandwich a portion of the tie bar to which the feed tray is attached. The elastomeric spring operates in shear with the spring rate of the elastomeric spring being adjusted by increasing/decreasing the compressive force exerted by the first and second elastomeric pads on the tie bar. The adjustable vibratory feeder has demonstrated greatly enhanced stability over other existing systems.