Roller Control System for Hospital Beds with Travel Drive Interlock
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Solution Overview
Problem
Existing control systems for rollers on movable units, such as hospital beds, fail to ensure safe and reliable operation by allowing unintended movement when in the brake position or during charging, leading to potential safety hazards.
Innovation Solution
The control system is designed to only activate the travel drive when the rollers are in the release or direction-setting position, and automatically sets the rollers to the brake position when the unit is stationary or charging, ensuring the travel drive cannot be activated in these states, with additional safety measures like motion sensors and automatic braking during mains connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the travel drive is allowed to operate when rollers are in brake position, then the movable unit can be moved more flexibly, but safety hazards arise from unintended movement
Solution Approach 1:
The control system applies preliminary anti-action by detecting the brake position of rollers before allowing travel drive activation. The control unit checks whether at least one roller is in the brake position and prevents travel drive operation accordingly, thereby eliminating safety hazards before they can manifest.
Solution Approach 2:
The system implements feedback by continuously monitoring the position of rollers through sensors and providing real-time information to the control unit. This feedback mechanism enables the control unit to make informed decisions about travel drive activation, ensuring safe operation while maintaining flexibility when conditions permit.
2Reliability
If automatic braking is activated when the unit is stationary, then safety is improved, but the travel drive cannot be activated even when needed
Solution Approach 1:
The control system applies dynamics by adapting its behavior based on the operational state of the movable unit. When the unit is stationary and rollers are in brake position, the system maintains this state for safety. However, when a travel command is received, the system dynamically transitions by activating the travel drive and adjusting roller positions accordingly, thus enabling movement when needed while maintaining safety during stationary periods.
Solution Approach 2:
The system implements self-service by automatically detecting its own state (stationary or moving) and autonomously making decisions about travel drive activation and roller positioning. The control unit monitors sensor inputs and automatically adjusts the system state without requiring manual intervention, ensuring both safety and operational responsiveness.
3Productivity
If the additional roller is kept in lowered position for travel, then mobility is maintained, but safety risks increase during charging or stationary periods
Solution Approach 1:
The control system applies preliminary action by automatically raising the additional roller to the raised position when the movable unit is detected to be stationary or when charging is initiated. This preliminary adjustment of roller position eliminates safety risks before charging or stationary periods begin, while allowing the roller to be lowered again when movement is required.
Data Source
AI summary
The invention relates to a control and to a method for controling rollers (2) mounted on a movable part such as, for example, a hospital bed (1), wherein one, several or all of the rollers (2) have a brake mechanism which can be set to a brake position and a release position, further preferably also to a direction-setting position, wherein, further, all the rollers (2) can be actuated electrically and one or several or all of the rollers (2) can in addition be actuated manually, and wherein, furthermore, an additional roller (3) with a wheel having a travel drive is provided, which additional roller (3) is preferably movable between a lowered position and a raised position. In order to obtain an advantageous control of the rollers in combination with the additional roller and also to provide an advantageous control method for this purpose, it is proposed that the travel drive can be activated only when the rollers (2) are located in the release position or the direction-setting position.