Hospital Bed Side-Rail Linkage for Constant Gap Control

Solution Overview

Problem

Existing bed designs with side rails face issues such as interference between the back side-rail and leg side-rail during tilting, which hinders the removal of medical equipment, causes patient discomfort, and increases the risk of body parts getting caught between the rails, leading to potential falls.

Innovation Solution

A bed with a link mechanism that synchronizes the movement of the leg side-rail with the tilting back bottom, ensuring a consistent gap between the side rails, preventing interference and allowing for secure placement of medical equipment without patient discomfort.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the back side-rail is moved along with the back bottom raising action, then the gap between side rails is stabilized, but the removal and securing of medical tubes and wires is hindered, and the patient feels uneasy

Engineering Contradiction:

Improvegap stability between side railsVSAvoidaccessibility for medical equipment

Core Design Contradiction:

Stability of the object's compositionVSEase of operation

Solution Approach 1:

The side rail system is divided into two independent segments: the back side-rail fixed to the back bottom and the leg side-rail fixed to the leg bottom. This segmentation allows each rail to move independently with its respective bottom section, preventing interference while maintaining gap stability. The leg side-rail can move along the longitudinal direction of the bed frame independently of the back side-rail's vertical movement.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A deck is introduced as an intermediary structure between the back bottom and the back side-rail. The back side-rail is fixed to this deck rather than directly to the back bottom, allowing the deck to mediate the movement and maintain proper positioning while enabling access for medical equipment around the back side-rail area.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-generated harmful factors

If the leg side-rail is moved in the direction separated from the back side-rail, then interference between side rails is avoided, but the gap opens too widely and the patient's body parts may get caught

Engineering Contradiction:

Improveinterference between side railsVSAvoidrisk of body entrapment

Core Design Contradiction:

Object-generated harmful factorsVSObject-affected harmful factors

Solution Approach 1:

The leg side-rail is designed to be movable along the longitudinal direction of the bed frame, allowing it to dynamically adjust its position. During back bottom raising, the leg side-rail moves in the direction separated from the back side-rail to avoid interference, while during normal operation it maintains a position that keeps the gap narrow enough to prevent body entrapment.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The gap width between the back side-rail and leg side-rail is changed dynamically based on the operational state. When the back bottom is raised, the leg side-rail position parameter is adjusted to increase the gap and avoid interference. When the bed is in normal position, the gap parameter is maintained at a smaller value to prevent patient body parts from getting caught.

Inventive Principle:

Principle #35Parameter changes

3Stability of the object's composition

If the back side-rail is fixed to the back bottom, then it moves with the back bottom raising action, but this causes patient discomfort and hinders medical equipment access

Engineering Contradiction:

Improverelative position stabilityVSAvoidmedical equipment accessibility

Core Design Contradiction:

Stability of the object's compositionVSEase of operation

Solution Approach 1:

The side rail system is divided into two independent segments: the back side-rail fixed to the back bottom and the leg side-rail fixed to the leg bottom. This segmentation allows each rail to move independently with its respective bottom section, preventing interference while maintaining gap stability. The leg side-rail can move along the longitudinal direction of the bed frame independently of the back side-rail's vertical movement.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A deck is introduced as an intermediary structure between the back bottom and the back side-rail. The back side-rail is fixed to this deck rather than directly to the back bottom, allowing the deck to mediate the movement and maintain proper positioning while enabling access for medical equipment around the back side-rail area.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS7810183B2Bed equipped with side rails

Publication Date: 2010.10.12 PARAMOUNT BED CO LTD

AI summary

A bed in which a gap between back and leg side-rails is kept constant when a back bottom is raised. A first link and a second link (2, 3) are rotatably supported at lower ends thereof on a frame (1). A coupling (6) is fixed to the base end part of a deck (7), and upper ends of the first and second links (2, 3) are rotatably connected to the coupling (6). An L-shaped rotator (4) is rotatably supported by the frame (1), and one end of a third link (5) is rotatably connected to an upper end (1c) of the rotator (4). The other end of the third link (5) is rotatably connected to the coupling (6). An actuator (13) is supported by the frame (1), and a piston rod (13a) is rotatably connected to a central portion (1b) of the rotator (4). The rotator (4) is turned by an advancing of the piston rod (13a); the relative positions of the fourth, fifth, and sixth links are changed; and the leg side-rail slides along the frame (1).