Over-Center Side Rail Linkage for Stable Bed Rail Positioning
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Solution Overview
Problem
Existing bed side rails lack a biasing mechanism to efficiently move between up and down positions, do not increase horizontal movement proportionally with vertical position change, and lack hard stops to prevent failure and secure storage.
Innovation Solution
A side rail design with parallel lever arms that rotate over center, incorporating a biasing mechanism using a cam and roller to urge the rail towards either position, and featuring hard stops and a release lever for secure positioning and easy actuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a side rail is permanently fixed to the bed frame, then structural stability is improved, but ease of operation deteriorates
Solution Approach 1:
The side rail is designed with a dynamic mounting system that allows it to be selectively positioned between an upper guarded position and a lower inoperative position. The mounting shafts enable rotational movement between these positions, transforming the fixed structure into a dynamic one that can adapt to different operational needs while maintaining structural integrity in each position.
Solution Approach 2:
The side rail assembly is divided into separable components including the side rail body, mounting shafts, and detachable mounting brackets. This segmentation allows the rail to be easily detached from the bed frame when not needed, providing both structural stability when mounted and ease of operation when repositioned or removed.
2Ease of operation
If a side rail is made movable between up and down positions, then ease of operation is improved, but reliability deteriorates
Solution Approach 1:
A retraction spring is incorporated into the mounting mechanism that automatically urges the side rail toward the bed frame when in the lowered position. This spring provides a cushioning force that ensures reliable return to the stowed position and prevents accidental detachment, maintaining reliability while allowing easy movement between positions.
Solution Approach 2:
The mounting shafts are designed with self-latching features that automatically secure the side rail in the upper guarded position without requiring additional fastening operations. The projection on the mounting shaft abuts the stop member to automatically limit and secure the movement, providing reliable positioning through self-service mechanisms.
3Device complexity
If the side rail moves only vertically, then device complexity is reduced, but productivity deteriorates
Solution Approach 1:
The side rail mounting mechanism incorporates both vertical and horizontal movement dimensions. When the mounting shafts rotate to move the rail to the raised position, the rail moves both vertically upward and horizontally outward, utilizing multiple spatial dimensions to achieve efficient positioning and storage in a compact manner.
4Ease of operation
If the side rail is positioned remote from the head board, then ease of operation is improved, but object-generated harmful factors worsen
Solution Approach 1:
The side rail mounting system is designed to dynamically adjust the rail's horizontal position relative to the head board. When in the upper guarded position, the rail is positioned remote from the head board for ease of operation and patient access. When lowered, the rail moves close to the head board, eliminating gaps and preventing harmful factors such as entrapment or instability.
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
The design enhances horizontal movement relative to vertical position change, provides a strong structure with hard stops to prevent failure, and allows for remote positioning and unobtrusive storage, while the release lever facilitates easy movement between positions.
Implementation Method 1
A spring is provided for biasing the side rail towards the down position
Implementation Method 2
The biasing mechanism can include a cam and roller
Implementation Method 3
Two parallel lever arms are also provided. The arms rotate over center when moving the body between the two positions. This increases the horizontal distance through which the side rail moves.
Data Source
AI summary
According to one embodiment of the present invention, a side rail is provided having a body selectably movable from a first up position to a second down position. Two parallel lever arms are also provided. The arms rotate over center when moving the body between the two positions. This increases the horizontal distance through which the side rail moves. A biasing mechanism can be provided to urge the side rail towards either the up or down position, and to bias away from an intermediate toggle position wherein the lever arms are vertical in a preferred embodiment. The biasing mechanism can include a cam and roller. A hard stop can be provided, whereby in the up position there is a strong component to prevent failure. A release lever is also provided. A person can actuate the release lever to move the side rail from the up position.