Hospital Bed Backrest Actuator Assembly with Emergency Gravity Release
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Solution Overview
Problem
Patient support devices, such as hospital beds, face delays in lowering the backrest during medical emergencies, and there is a risk of damage or injury from objects or body parts getting lodged between the lowering backrest and the bed frame.
Innovation Solution
An actuator assembly with a lockable damper that allows the backrest to lower due to gravity over a damped range of motion, which can be stopped at any position, incorporating a mechanical release mechanism for emergency situations, such as CPR, to facilitate quick and controlled movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If an electrically powered actuator is used to control the backrest position, then the backrest can be raised and lowered, but time is wasted waiting for the actuator to lower the backrest during medical emergencies
Solution Approach 1:
The system dynamically switches between two operational modes: normal controlled lowering via electric actuator, and emergency rapid lowering via gravity-assisted release. The release mechanism allows the backrest to transition from actuator-controlled positioning to gravity-driven rapid descent when emergency release members are actuated, resolving the contradiction between controlled operation and emergency speed.
Solution Approach 2:
The emergency release mechanism extracts the backrest positioning from the electric actuator's control during emergencies. By providing separate emergency release members that directly release the backrest from its supported position independent of the actuator's slowing influence, the system enables rapid lowering without waiting for the actuator to complete its cycle.
2Speed
If the backrest is lowered rapidly during an emergency, then emergency procedures can be administered faster, but objects or body parts can become lodged between the backrest and bed frame causing injury or damage
Solution Approach 1:
The system provides beforehand protection by incorporating multiple safety features: (1) The backrest is designed to lower along a controlled path that minimizes pinching hazards, (2) Emergency release members are positioned and designed to allow controlled release rather than uncontrolled dropping, (3) The mechanical release mechanism includes features to prevent complete uncontrolled collapse while enabling rapid positioning for CPR.
Solution Approach 2:
The mechanical release mechanism acts as an intermediary between the emergency release members and the backrest. It translates the activation of release members into controlled gravitational lowering, mediating between the need for rapid movement and the need to prevent pinching injuries. The mechanism allows energy dissipation and controlled motion rather than direct uncontrolled collapse.
3Loss of time
If a mechanical release mechanism is added for emergency lowering, then rapid backrest lowering is enabled, but the device complexity increases
Solution Approach 1:
The emergency release mechanism is designed to be self-service in the sense that it utilizes the patient's own body weight and gravity to perform the lowering action. Once the release members are actuated, gravity automatically provides the force needed to lower the backrest without requiring additional power sources, complex control systems, or external assistance. The system serves itself using naturally available energy.
Solution Approach 2:
The actuator assembly is segmented into distinct functional components: the electric actuator for normal operation, the release mechanism for emergency mode, and the connection elements. This segmentation allows each component to be optimized independently and simplifies the overall design by clearly separating normal operation functions from emergency release functions, reducing the complexity burden of the added emergency capability.
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
Enables rapid and controlled lowering of the backrest during emergencies, reducing the risk of injury and damage, while allowing for safe operation by stopping the backrest at any desired position along its range of motion.
Implementation Method 1
The actuator assembly is further configured to release the backrest to lower due to gravity over a damped range of motion
Implementation Method 2
The actuator assembly can include an actuator connected in series with a damper and locking structure to selectively prevent shortening or collapse of the damper
Implementation Method 3
The actuator assembly is further configured to release the backrest to lower due to gravity over a damped range of motion
Data Source
AI summary
A backrest of a bed is pivotable with respect to a bed frame. A backrest actuator assembly connects the backrest to the bed frame. The backrest actuator assembly is configured to raise and lower the backrest with respect to the bed frame by way of an actuator. The backrest actuator assembly is further configured with a lockable damper to release the backrest to lower due to gravity over a damped range of motion. The backrest can be so lowered during an emergency, such as an emergency that requires administration of CPR to the bed's occupant. The lockable damper can stop the lowering of the backrest at any position along the damped range of motion. After an emergency lowering, the backrest actuator assembly can automatically reset to a normal operation state.