Ladder Hinge Lock Plate Retainer Mechanism
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Solution Overview
Problem
Conventional ladders, particularly combination ladders, face challenges in balancing strength, ease of use, stability, and safety while accommodating various loadings and configurations, with existing designs often compromising on manufacturing cost and efficiency.
Innovation Solution
The design incorporates a pair of hinge mechanisms with a lock plate and retainer system that allows selective rotation and locking of rail assemblies, enabling the ladder to be configured as a stepladder, extension ladder, or stowed state, using a combination of hinge plates, spacer plates, and biasing members for adjustable and secure positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional hinge mechanisms are used to enable selective rotational adjustment of rail assemblies, then the ladder can be placed in multiple configurations (stepladder, extension ladder, collapsed state), but the design complexity increases to accommodate various loadings and positions
Solution Approach 1:
The hinge mechanism is divided into separate functional components: a hinge assembly with hinge plates for rotational movement, and a distinct adjustment mechanism with a lock plate, retainer, and release structure for positioning and locking. This segmentation allows each component to be optimized independently for its specific function.
Solution Approach 2:
The locking function is extracted from the hinge assembly and implemented through a separate adjustment mechanism. The lock plate, retainer, and release structure form an independent subsystem that can be engaged or disengaged as needed, rather than being integrated into the hinge structure itself.
2Reliability
If locking mechanisms are added to enable selective adjustment of rail and rung assemblies, then height adjustment and stability are improved, but the ease of operation decreases due to additional manual intervention required
Solution Approach 1:
The retainer is spring-biased to automatically engage with the lock plate and hold it in the engaged position without requiring continuous user input. Once the release structure is actuated to disengage the retainer, the system self-regulates the locking state, reducing the operational burden on the user.
Solution Approach 2:
The adjustment mechanism operates in discrete periodic cycles: the release structure is actuated to disengage the retainer, the lock plate is moved to a new position, and the retainer automatically re-engages to lock it. This periodic engagement-disengagement pattern simplifies operation compared to continuous adjustment mechanisms.
3Strength
If multiple components (hinge plates, spacer plates, lock plate, retainer, release structure) are used to achieve secure positioning, then the strength and stability improve, but the manufacturing cost and complexity increase
Solution Approach 1:
The structure is segmented into discrete, standardized components (hinge plates, spacer plates, lock plate, retainer, release structure) that can be manufactured independently using standard fabrication processes. This segmentation enables modular assembly and simplifies quality control and manufacturing planning.
Solution Approach 2:
The hinge mechanism components are designed with universal features that allow them to be used across different ladder configurations and positions. The lock plate, retainer, and release structure serve multiple functions including locking, positioning, and guiding movement, reducing the need for specialized components for each function.
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
This solution enhances the ease of use, stability, and safety of ladders by allowing versatile configurations while maintaining structural integrity and cost-effectiveness through efficient manufacturing techniques, enabling the ladder to be used in multiple positions and states without compromising on strength or ease of handling.
Implementation Method 1
A biasing member is positioned between the release structure and the lock plate and is configured to bias the release structure away from the lock plate
Implementation Method 2
a first hinge assembly having at least one hinge plate, a second hinge assembly having at least one hinge plate, the first hinge assembly being rotatably coupled to the second hinge assembly about a hinge pin
Data Source
AI summary
Ladders, ladder components and related methods are provided including embodiments of a hinge that may be used in a combination ladder. In one embodiment, a hinge mechanism includes a first hinge assembly and a second hinge assembly. The first and second hinge assemblies are coupled together for relative rotation about a defined axis. An adjustment mechanism enables the two hinge assemblies to be selectively locked or unlocked to prohibit or permit relative rotation, respectively. In one embodiment, the adjustment mechanism includes a lock plate displaceable along a first axis and a retainer displaceable along a second axis. The retainer is configured to hold the lock plate in a disengaged state until a release structure displaces the retainer away from the lock plate. The release structure may be configured to be actuated and displace the retainer upon relative rotation of the hinge assemblies to (or through) a predetermined angular configuration.