Double Parallelogram Armrest Mechanism for Compact Wheelchair Support
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Solution Overview
Problem
Existing moving aids for the arm are bulky, making it difficult to navigate through small openings and are often exhausting to operate, as they struggle to support the weight and follow desired arm movements without wear or compactness.
Innovation Solution
A moving aid featuring a double parallelogram mechanism with a conductor-track and a balanced armrest, allowing for compact and robust horizontal movement, with a hinged system and locking mechanism to secure positions and reduce user effort, and a covered conductor-track for safety and aesthetics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing moving aids are designed to support arm weight and movement, then they provide functional assistance, but they become voluminous and difficult to navigate through small openings
Solution Approach 1:
The support structure is divided into two parallelograms (first and second parallelograms) that work together to provide arm support. This segmentation allows the device to maintain support functionality while reducing overall volume and improving maneuverability through tight spaces.
Solution Approach 2:
The second parallelogram is nested within or integrated with the first parallelogram structure, allowing the carrier to be supported compactly. This nesting approach enables the device to provide full arm support functionality while minimizing the volume required for navigation through small openings.
2Ease of operation
If sliding constructions are used to support arm movement, then they allow horizontal movement, but they wear out quickly under arm weight and load
Solution Approach 1:
The parallelogram mechanism is designed to distribute and counterbalance the arm weight and load across its structural members. This counterbalancing approach reduces the stress on individual components, preventing rapid wear while maintaining smooth horizontal movement capability.
Solution Approach 2:
Instead of using sliding constructions that wear under load, the patent inverts the approach by using a parallelogram linkage mechanism where the geometry itself provides the movement guidance. This inversion transforms the support mechanism from a sliding system to a rigid linkage system that withstands load without wear.
3Measurement precision
If the arm support is designed to follow desired arm movement paths, then it provides precise positioning, but the operation becomes intensive and exhausting for users
Solution Approach 1:
The parallelogram mechanism is designed to maintain the carrier at a consistent height and orientation throughout its range of motion. This equipotential design reduces the effort required by users as the arm moves horizontally, while the conductor-track ensures precise following of the desired movement path.
Solution Approach 2:
The conductor-track acts as an intermediary element that guides the lower end of the leg extending beyond the second lower side. This intermediary component ensures the second upper side of the second parallelogram follows the desired horizontal track accurately, providing precise positioning without requiring intensive user operation.
4Ease of operation
If the conductor-track is exposed for functionality, then it allows smooth movement guidance, but it is susceptible to dirt entry and malfunctioning
Solution Approach 1:
A cover is introduced that encloses the conductor-track, protecting it from dirt and contamination. The cover design allows the conductor-track to continue guiding movement smoothly while shielding it from harmful environmental factors that could cause malfunctioning.
Data Source
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AI summary
Moving aid for the (fore)arm of a person, comprising an armrest for receiving the (fore)arm of a person; a carrier for the arm rest; a support, for movably supporting the carrier with respect to a (wheel)chair, work place, bed or other fixed world, wherein the support comprises a first parallelogram, having a first essentially horizontal extending upper side, connected to the (wheel)chair, and a first lower side, situated below the upper side, coinciding with a second lower side, forming part of a second parallelogram, which second parallelogram comprises a second upper side, situated above the first upper side of the first parallelogram and which holds the carrier; and wherein at least one of the legs of the second parallelogram that connect the second lower side and the second upper side extends beyond the second lower side; and wherein the lower end of the at least one leg that extends beyond the second lower side is beared in a conductor-track, which conductor-track is formed such that a second upper side of the second parallelogram is urged in an essentially horizontal track.