Spring Retention Assembly for Jack Pin and Bushing
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Solution Overview
Problem
Mechanical jacks require time-consuming and damaging disassembly processes due to interference fits, leading to component damage and restrictive manufacturing tolerances, making servicing and replacement challenging.
Innovation Solution
A spring retention assembly that secures a pinion gear to a cross shaft and a bushing to a jack housing without interference fits, allowing for easy removal and assembly by hand without tools, using a compression spring to retain the pin and bushing within loosely fitting apertures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If interference fit is used to secure pins and bushings, then component retention strength is improved, but ease of disassembly deteriorates
Solution Approach 1:
The retention mechanism is segmented into two independent functions: a loose-fit pin/bushing for easy removal and a separate spring mechanism for secure retention. The spring is divided into segments that engage with the pin/bushing and housing walls independently, allowing the pin to be removed without the spring while maintaining strong retention during operation.
Solution Approach 2:
The spring acts as an intermediary between the pin/bushing and the housing walls. Instead of the pin/bushing directly engaging the housing walls through interference fit, the spring mediates this connection by applying radial outward force against the housing walls, thereby securing the pin/bushing indirectly and allowing easy removal when needed.
2Strength
If interference fit is used to secure pins and bushings, then component retention strength is improved, but manufacturing precision requirements worsen
Solution Approach 1:
The system separates the retention function from the positioning function. The pin/bushing provides precise positioning with loose fit (tolerant manufacturing), while the spring provides retention strength (insensitive to tolerances). This segmentation allows each component to be manufactured with relaxed tolerances while achieving both positioning accuracy and strong retention.
Solution Approach 2:
The invention changes the fit parameter from interference fit (tight tolerance required) to loose fit (relaxed tolerance acceptable). The retention strength is then achieved through a different parameter - the spring force - rather than through the fit between pin and housing. This parameter change eliminates the need for tight manufacturing tolerances.
3Strength
If interference fit is used to secure pins and bushings, then component retention strength is improved, but ease of repair deteriorates
Solution Approach 1:
The repair process is segmented into simple steps: remove the retaining spring, remove the pin/bushing, service the component, and reassemble in reverse order. The spring and pin are independent removable components, allowing technicians to service pins and bushings without damaging other jack components, significantly improving ease of repair.
Solution Approach 2:
The retaining spring is extracted as a separate removable component that can be independently removed to access the pin and bushing for servicing. This extraction of the retention mechanism allows complete disassembly and servicing of internal jack components without permanent damage or complex procedures.
4Strength
If interference fit is used to secure pins and bushings, then component retention strength is improved, but device complexity worsens
Solution Approach 1:
While the system has multiple components (spring, pin, bushing), each serves a simple, well-defined function. The spring provides retention, the pin provides positioning, and the bushing provides support. This clear segmentation of functions, while adding components, actually simplifies the overall design by eliminating the need for precise interference fit calculations and tight tolerance manufacturing, reducing design and manufacturing complexity.
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
Facilitates efficient and damage-free servicing of jack assemblies, reducing manufacturing complexity and enabling broader compatibility of parts across different jack models.
Implementation Method 1
a compression spring to retain components loosely within their apertures
Data Source
AI summary
A retention assembly for a jack is disclosed. The retention assembly includes a housing, a bushing, a shaft, a gear, a pin, and a spring. The housing includes a housing aperture, into which the bushing is positioned. The shaft, which includes a shaft aperture, extends through the bushing such that the portion of the shaft defining the shaft aperture is positioned within the housing. The gear, which includes a gear aperture, is positioned on the shaft such that the gear and shaft apertures align to accommodate the pin. The spring is positioned on the shaft and within the housing such that a first end of the spring applies a force to the bushing to retain the bushing in the housing aperture and a second end of the spring engages the pin to retain the pin within the shaft and gear apertures.