Expandable Step Stool Tray Linkage for Object Stability

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Solution Overview

Problem

Conventional step stools with foldable frames lack an efficient tray assembly that maintains object orientation during transitions between collapsed and expanded positions, leading to potential object displacement.

Innovation Solution

An expandable tray assembly with a fixed tray unit and a movable tray panel, guided by a tray-motion controller linkage, ensures the top surface remains upwardly facing, maintaining object stability during transitions between collapsed and expanded positions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional tray assembly is used in a foldable step stool, then the tray can hold items during use, but the objects may become displaced or fall during transitions between collapsed and expanded positions

Engineering Contradiction:

Improveobject stabilityVSAvoidtransition smoothness

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The tray assembly is designed with a movable tray panel that dynamically changes position relative to the fixed tray unit. The tray panel moves from a first position (aligned with the step) to a second position (aligned with the fixed tray unit), allowing the system to adapt its configuration during transitions while maintaining object stability through controlled motion guidance.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

A linkage mechanism acts as an intermediary between the movable tray panel and the fixed tray unit. This linkage guides the motion of the tray panel, ensuring smooth transitions while preventing objects from displacing or falling during the transition between collapsed and expanded positions.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Quantity of substance

If the tray assembly is expanded to provide more storage space, then the storage capacity increases, but the device complexity increases

Engineering Contradiction:

Improvestorage capacityVSAvoidtray assembly structure

Core Design Contradiction:

Quantity of substanceVSDevice complexity

Solution Approach 1:

The tray assembly is segmented into distinct components: a fixed tray unit and a movable tray panel. This segmentation allows the tray to expand storage capacity by adding the movable panel while keeping each individual component relatively simple in structure, thereby managing overall device complexity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The movable tray panel serves multiple functions: it provides additional storage space when expanded, maintains object stability during transitions through guided motion, and can be integrated with the step stool's existing folding mechanism. This multi-functionality increases storage capacity without proportionally increasing structural complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS11299934B2Expandable work tray for a step stool or ladder

Publication Date: 2022.04.12 DOREL HOME FURNISHINGS INC

AI summary

A step stool includes an expandable tray assembly. The expandable tray assembly has a fixed tray panel and a movable tray panel coupled to the fixed tray unit for movement relative to the fixed tray unit. The movable tray panel is illustratively movable between a collapsed position, arranged above the fixed tray panel, and an expanded position, arranged adjacent to the fixed tray panel.