Stepladder Gate Inward Opening Strike Plate Mechanism
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Solution Overview
Problem
Existing collapsible stepladders with railings and gates lack enhanced safety and kinematic simplicity, particularly in deployment and stability, especially when used at varying heights or on non-horizontal surfaces.
Innovation Solution
A stepladder design featuring automatic gate operation that opens inwardly and is kept pressed against a fixed beat, with hinged and slidably mounted control rods, telescopic parts for height adjustment, and stabilizing feet for improved stability, allowing for rapid, safe, and simple deployment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the gate is hinged on the connecting rods of a parallelogram, then the gate can be supported, but the force is transmitted to the uprights increasing the magnitude requiring thicker upright profiles
Solution Approach 1:
The patent extracts the gate support function from the parallelogram connecting rods and relocates it to a dedicated strike plate fixed to the upright. This separates the gate's support mechanism from the structural load-bearing elements, allowing the gate to be supported without requiring thicker upright profiles.
Solution Approach 2:
The strike plate acts as an intermediary element between the gate and the upright. Instead of the gate forces being directly transmitted to the uprights through the parallelogram mechanism, the strike plate mediates this force transmission, providing a dedicated support surface that reduces the structural requirements of the uprights.
2Reliability
If the platform is independent of the guardrail, then the platform is unaffected by forces on the guardrail, but the deployment kinematics become more complex
Solution Approach 1:
The patent segments the stepladder into independent functional modules: the platform, the guardrail with its control bars, and the strike plate. This segmentation allows the platform to remain independent from guardrail forces while maintaining a relatively simple deployment mechanism through the hinged connection of these modular components.
3Ease of operation
If the gate opens outwardly, then the gate can be accessed easily, but accidental opening is more likely occurring when user feels unwell
Solution Approach 1:
The patent inverts the conventional gate opening direction by designing the gate to open inwardly toward the guardrail rather than outwardly. This inversion, combined with the strike plate mechanism, prevents accidental outward opening while maintaining ease of access when needed, as the gate can still be deliberately opened inward for entry.
Data Source
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AI summary
The invention relates to a safety stepladder (1) comprising: - two parallel uprights (6) joined by crossbars (7) to define a climbing platform (5); - two support legs (9), each hinged at the top of one of the uprights (6) to occupy a storage position against the uprights (6), or a stabilizing position away from the uprights (6); - a platform (2) hinged between the two uprights (6) and the two support legs (9) and foldable between a horizontal working position when the legs (9) are in the stabilizing position, and a folded position against the climbing platform (5) when the legs (9) are in the storage position; - a guardrail (3) hinged at the top of the climbing platform (5) and capable of adopting, under the action of first and second control bars (11, 12), a folded position against the climbing platform (5) or a horizontal safety position.According to the invention, the first control bar (11) receives a hinged gate (4) to open inwards towards the guardrail (3) against an elastic return device (15) of the guardrail (3) in the closed position against the second control bar (12) which then acts as a fixed strike plate.