Actuatable Leg Section Sequencing for Bed Sitting
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Solution Overview
Problem
Existing medical beds face challenges in transitioning from a flat to a sitting configuration, causing discomfort due to stress on the hamstrings, sliding of the patient, and increased pressure in the lower back region, as the reclinable back and leg sections are often actuated simultaneously, leading to undesirable outcomes.
Innovation Solution
A bed with a reclinable back section and actuatable leg section, featuring a control unit that sequences the actuation phases to raise the leg section first, then both sections together, and finally adjust them to specific final positions, reducing stress and sliding by controlling the angle of inclination, particularly using a reverse Trendelenburg sitting position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the reclinable back section and actuatable leg section are actuated simultaneously when switching from substantially flat configuration to sitting configuration, then the configuration change is efficient, but it causes stress on the patient's hamstrings, undesired sliding of the patient on the mattress surface, and increased pressure in the lower back region
Solution Approach 1:
The patent applies preliminary action by raising the actuatable leg section to an intermediate position before raising the reclinable back section to the final sitting position. This sequence prevents the patient's hamstrings from being stressed and avoids sliding by preparing the leg section in advance. The control unit is configured to actuate the leg section first to an intermediate position, then subsequently raise the back section, ensuring patient comfort during the configuration transition.
2Object-affected harmful factors
If the reclinable back section is raised and the actuatable leg section is returned to fully flat configuration (as in EP 1 346 671 A1), then abdominal pressure is reduced, but the patient may slide on the mattress surface in the sitting configuration
Solution Approach 1:
The patent applies local quality by maintaining the actuatable leg section in a raised position rather than returning it to fully flat configuration. This localized adjustment of the leg section position prevents patient sliding on the mattress surface while the controlled sequencing of actuation phases manages abdominal pressure. The leg section remains elevated to provide stability and prevent sliding, contrasting with the prior art approach of returning it to flat position.
3Device complexity
If a simple actuation sequence is used without intermediate positions, then the control system is simple, but patient comfort is compromised due to stress and sliding
Solution Approach 1:
The control unit is configured with a multi-phase actuation sequence that raises the actuatable leg section to an intermediate position before raising the reclinable back section to the final sitting position. This preliminary action at the intermediate position prevents patient discomfort by avoiding hamstring stress and sliding, while maintaining relatively simple control logic through structured phase management rather than complex continuous control.
Data Source
Figure 1A
Figure 1B
Figure 2A
AI summary
The bed (1) comprises a support structure (10) and an actuatable mattress support platform (50), which actuatable mattress support platform (50) comprises a reclinable back section (51) and an actuatable leg section (53/54). The actuatable leg section (53/54) includes a reclinable thigh section (53) and a reclinable lower- leg section (54) that are adapted to move in conjunction with one another. The reclinable back section (51) and actuatable leg section (53/54) are actuatable to adjust a configuration of the actuatable mattress support platform (50) and change the configuration of the actuatable mattress support platform (50) from a substantially flat configuration to a sitting configuration, or vice versa. During a first actuation phase, exclusively the actuatable leg section (53/54) is actuated to raise the actuatable leg section (53/54) with respect to the support structure (10), thereby bringing the actuatable leg section (53/54) to a first intermediate position with respect to the support structure (10). During a subsequent second actuation phase, both the reclinable back section (51) and the actuatable leg section (53/54) are actuated to respectively raise the reclinable back section (51) and raise further the actuatable leg section (53/54) with respect to the support structure (10), thereby bringing the actuatable leg section (53/54) to a second intermediate position with respect to the support structure (10) higher than the first intermediate position. During a subsequent third actuation phase, both the reclinable back section (51) and the actuatable leg section (53/54) are actuated to respectively raise further the reclinable back section (51) and lower the actuatable leg section (53/54) with respect to the support structure (10), thereby bringing the reclinable back section (51) and actuatable leg section (53/54) to selected final positions in which the reclinable back section (51) and the actuatable leg section (53/54) are both raised with respect to the support structure (10).