Collapsible Spreader Closure Structure Calibration
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Solution Overview
Problem
Collapsible lawn and garden spreaders lose calibration when the handle is folded, requiring repeated calibration by the user, which is time-consuming, costly, and prone to errors due to tolerance build-up in the handle pivot joint.
Innovation Solution
A collapsible spreader design featuring an adjustable and movable closure structure with a lever and wire actuator system, a biasing structure, and a selection mechanism that eliminates the need for recalibration by fixing the closure structure's length during factory assembly, ensuring consistent spread rate settings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a micrometer is used for calibration and rate setting, then spread rate control is improved, but the device loses calibration when the handle is folded requiring repeated user calibration
Solution Approach 1:
The closure structure is pre-adjusted and pre-calibrated at the factory during assembly to establish the correct spread rate settings. This preliminary calibration is performed once during manufacturing, eliminating the need for repeated user calibration after handle folding and unfolding cycles.
Solution Approach 2:
The micrometer calibration mechanism is removed from the device entirely. Instead of using a micrometer that requires repeated adjustment, the invention uses a fixed closure structure with predetermined openings that are calibrated during factory assembly, extracting the problematic calibration component from the system.
2Adaptability or versatility
If the handle pivot joint is used for collapsible functionality, then storage and shipping convenience is improved, but tolerance build-up causes calibration loss
Solution Approach 1:
The calibration adjustment mechanism (micrometer) is extracted from the device, eliminating the source of precision loss caused by handle pivot joint tolerances. The closure structure becomes a fixed component calibrated once at the factory, insensitive to handle positioning variations.
Solution Approach 2:
The closure structure is pre-positioned and pre-calibrated at the factory to account for any potential variations in handle pivot joint tolerances. This preliminary setup ensures that calibration is established before the device reaches the user, compensating for mechanical tolerances in the collapsible mechanism.
3Measurement precision
If factory calibration is performed, then initial spread rate accuracy is improved, but repeated user recalibration is required increasing time and cost
Solution Approach 1:
The closure structure is calibrated once during factory assembly with predetermined openings matched to product packaging numbers. This single preliminary calibration action during manufacturing eliminates the need for repeated user recalibration, saving significant time and reducing the risk of user error.
Solution Approach 2:
The invention replaces the expensive and time-consuming repeated calibration process with a simple, fixed closure structure that requires no user adjustment. The calibration is performed once at the factory using inexpensive methods, and the setting is maintained throughout the product's service life without requiring user intervention.
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 simplifies manufacturing and assembly, reduces costs, enhances reliability, and eliminates the need for user recalibration, maintaining consistent spread rates without micrometer adjustments.
Implementation Method 1
a first biasing structure is included for biasing the closure structure into position to block the hopper opening
Implementation Method 2
the actuator structure includes a lever and a wire and a second biasing structure is provided to operatively connect between the lever and the wire
Data Source
AI summary
An improved collapsible spreader with a spread rate selection mechanism including a knob and a rotatable cup-shaped structure. The cup-shaped structure includes an elongated setting tab and a thirty-six step edge corresponding to thirty-six spread rate settings on the knob. Operatively engaged with the cup-shaped structure is an abutment tab that is part of a closure structure for blocking and selectively unblocking a hopper opening. The tab engages the setting tab to define the adjustable length of the closure structure. Thereafter, abutment rate selection is a function of the rotatable position of the cup-shaped structure. Engagement of the abutment tab and a step defines the size of the hopper opening and thus the amount of product released from the hopper during operation. The spreader also includes a dual spring arrangement to bias the closure structure to a closed position and to prevent breakage. The disclosed spreader also features a one piece wheel to reduce parts and assembly costs.