Pivoting Ladder Shoe with Automatic Safety Locking
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Solution Overview
Problem
Existing ladder levelers lack effective mechanisms for secure footing on slippery surfaces and efficient operation, particularly in adjusting and retracting ladder legs, which can lead to instability and difficulty in use.
Innovation Solution
The design incorporates a nailable, pivoting shoe with strategically placed holes for nail insertion, a retractable ladder leveler with improved foot-operable control, and an extendable and adjustable ladder leg with a claw mechanism that allows for better grip and automatic safety locking, enabling the shoe to pivot and lock in place on slippery surfaces without requiring leg extension.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional fixed ladder shoe is used, then the structure is simple, but the ladder lacks stability on slippery surfaces and cannot adapt to different ground conditions
Solution Approach 1:
The shoe is designed to pivot 90 degrees from a retracted position to an extended position, transforming from a static structure to a dynamic one that can adapt to different ground conditions. This pivoting action allows the shoe to engage with slippery surfaces effectively while maintaining structural simplicity
Solution Approach 2:
The shoe is separated from the ladder leg as an independent pivotable component, allowing it to move independently to provide grip on slippery surfaces. This segmentation enables the shoe to function as a separate gripping mechanism without complicating the overall ladder structure
2Ease of operation
If manual adjustment of ladder legs is required, then the mechanism is simple, but the operation becomes difficult and time-consuming
Solution Approach 1:
The shoe incorporates an automatic locking mechanism that engages and disengages based on the pivoting motion itself. When the shoe pivots to the extended position, it automatically locks; when returned to the retracted position, it automatically releases. This eliminates the need for manual locking operations and reduces adjustment time
Solution Approach 2:
The shoe is pre-configured with the locking mechanism in such a way that the act of pivoting itself performs the locking function. The geometry of the pivot connection is designed so that the extended position naturally engages the lock, preparing the system for immediate use without additional steps
3Reliability
If the shoe is fixed to the ladder leg, then the structure is stable, but the shoe cannot pivot to engage slippery surfaces
Solution Approach 1:
The connection between the shoe and ladder leg is designed as a pivot joint that allows controlled movement. The shoe can pivot 90 degrees to engage slippery surfaces while the pivot joint maintains structural stability through proper mechanical design, combining mobility with structural integrity
Solution Approach 2:
The pivot joint acts as an intermediary mechanism between the fixed ladder leg and the movable shoe. It allows the shoe to rotate independently to provide grip while maintaining a stable connection to the ladder structure, resolving the conflict between mobility and structural stability
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 enhanced stability and ease of use by ensuring secure footing on various surfaces, automatic safety locking, and ergonomic operation, allowing for quick extension and retraction of ladder legs without manual effort, even on uneven or slippery surfaces.
Implementation Method 1
a retraction spring 53 coupled at one end to the outer housing at a spring fastener 55 and at the other end to the leg extension 71. The retraction spring continually applies an upward biasing force on the leg extension.
Implementation Method 2
a pawl 73 mounted on a pivot pin 79 and biased into engagement by a pawl spring 81. The pawl engages ratchet teeth 49 on a toothed ratchet bar 47
Implementation Method 3
The support foot 27 includes a rubber friction pad tread 31.
Data Source
AI summary
Improvements to the leg extension of an adjustable ladder leveler and, more generally, improvements to ladder legs. A shoe with a claw that folds to be parallel to the ladder leg and then slides upward with respect to the leg thereby becoming locked into position so that it cannot move away from being parallel so long as weight is applied on the ladder. If the shoe is on an extension, as the shoe slides up, it engages a safety bar that prevents release of the extension.