Stair Traversing Mechanism With Cyclical Step Frame Motion

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Solution Overview

Problem

Existing stair traversing devices are complex, costly, and require active electronic control, making them prone to errors and high maintenance, while also being unsuitable for stable, level orientation without tilting or additional assistance.

Innovation Solution

A mechanical stair traversing device utilizing a uniquely shaped step frame with a cyclical motion mechanism, driven by actuators, that maintains a stable, level orientation by translating along a closed path relative to the payload body, allowing it to traverse stairs without active control, using a non-rotating connection and cyclical motion mechanism.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If existing stair traversing devices use coordinated walking elements or articulating wheel sets with feedback control, then the device can traverse stairs, but the device complexity increases and requires active electronic control

Engineering Contradiction:
Improvestair traversal capabilityVSAvoidmechanical complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The step frame assembly is designed to automatically conform to stair steps through its unique geometry. The L-shaped configuration with horizontal and vertical portions allows the assembly to self-position on steps without requiring active electronic control or complex coordination mechanisms. The geometry itself provides the adaptation capability.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The invention changes the geometric parameters of the traversing mechanism by using an L-shaped step frame assembly with specific horizontal and vertical portions. This geometric parameter change allows the mechanism to naturally adapt to stair geometry without requiring active control systems.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If existing solutions use multiple moving components driven by multiple actuators, then the device can navigate stairs, but the reliability decreases due to synchronized control requirements

Engineering Contradiction:
Improvestair navigation capabilityVSAvoidsystem reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The invention extracts the complex synchronized control system from the stair traversing mechanism. By using a single actuator to drive the step frame assembly through its cyclical motion, the patent removes the need for multiple actuators and their coordination, thereby improving reliability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Multiple functions are merged into a single step frame assembly. The L-shaped assembly simultaneously provides support, positioning, and motion transformation capabilities that would otherwise require multiple separate components and actuators working in coordination.

Inventive Principle:
Principle #5Merging (Combining)

3Adaptability or versatility

If material handling devices tilt the payload to balance center of mass, then the device can traverse stairs, but the ease of operation decreases and requires human operator stabilization

Engineering Contradiction:
Improvestair traversal capabilityVSAvoidoperator effort
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The step frame assembly maintains the payload body in a level orientation throughout the stair traversal process. By keeping the center of mass at a constant height relative to the payload body, the mechanism eliminates the need for operator intervention to stabilize or reposition the load.

Inventive Principle:
Principle #12Equipotentiality

Solution Approach 2:

The mechanism automatically maintains payload levelness through the geometric design of the step frame assembly. The L-shaped configuration ensures that as the assembly moves through its cyclical motion on stairs, the payload body remains horizontal without requiring operator adjustment or stabilization efforts.

Inventive Principle:
Principle #25Self-service

4Ease of operation

If mobility devices are designed for level surfaces, then the ease of operation is maintained, but the adaptability to traverse stairs is lost

Engineering Contradiction:
Improveoperational simplicityVSAvoidstair traversal capability
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The step frame assembly incorporates dynamic motion through its cyclical movement driven by a single actuator. This dynamic capability allows the mechanism to adapt to stair geometry while maintaining simple operation, combining the benefits of both level-surface simplicity and stair-traversal capability.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3380387B1Stair traversing device
Publication Date: 2021.04.28 QUANTUM ROBOTIC SYST INC
  • EP3380387B1 patent drawingFigure 1~2
  • EP3380387B1 patent drawingFigure 3A~3D
  • EP3380387B1 patent drawingFigure 4~5B

AI summary

A stair traversing device comprising a payload body for transporting a payload, a step frame, and a mechanism between the step frame and the payload body to move the step frame relative to the payload body along a cyclical path. The mechanism drives a movement of one of the payload body and the step frame along a first segment of the cyclical path from a retracted configuration to an extended configuration, and drives a movement of the other one of the payload body and the step frame along a second segment of the cyclical path back into the retracted configuration. The payload body and the step frame are configured to remain fixedly in position on a stair when the other one of the payload body and the step frame is moved. The mechanism is configured to maintain the relative orientation between the payload body and the stair.