Cable-Driven Foot Section Actuation for Patient Beds
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Solution Overview
Problem
Conventional patient support apparatuses require significant manual effort to adjust the foot section, especially for heavier patients, and linear actuators often occupy valuable space on the support frame.
Innovation Solution
A patient support apparatus with a powered foot section actuation system that uses a support link and guide tracks to facilitate the adjustment of the foot section relative to the leg section, allowing for efficient elevation and lowering without the need for extensive manual effort, and an alternative manual telescoping assembly for flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If manual adjustment of the foot section is used, then the device complexity is reduced, but the ease of operation deteriorates due to considerable effort needed especially for heavier patients
Solution Approach 1:
The patent replaces the traditional mechanical linear actuator system with a cable-driven pulley system. The cable runs through a pulley mechanism that provides mechanical advantage, allowing manual adjustment of the foot section with significantly reduced effort. This substitution maintains the mechanical nature of the system while improving ease of operation by redistributing forces through the cable and pulley arrangement.
Solution Approach 2:
The cable acts as an intermediary element between the user's manual input and the foot section. By threading the cable through a pulley system attached to the support frame and foot section, the mechanism translates small manual forces into the larger forces needed to move the foot section, especially when supporting heavier patients.
2Ease of operation
If a linear actuator is used to raise or lower the free end of the foot section, then the ease of operation is improved, but the area of stationary object increases due to space occupied on the support frame
Solution Approach 1:
The patent extracts the bulky linear actuator from the support frame structure and replaces it with a compact pulley system. The cable-based mechanism eliminates the need for a large motorized actuator, thereby freeing up valuable space on the support frame while maintaining the ability to easily adjust the foot section position.
Solution Approach 2:
Instead of using a motorized actuator that pushes or pulls the foot section directly, the patent inverts the approach by using a cable-pulley system where the cable loops around the pulley and attaches to both the support frame and foot section. This inverted mechanical arrangement achieves the same function with significantly reduced space requirements.
3Productivity
If manual adjustment of the foot section is used, then the device complexity is reduced, but the productivity deteriorates due to time-consuming adjustments
Solution Approach 1:
The cable-pulley system replaces traditional manual adjustment mechanisms, providing a more efficient way to move the foot section. The pulley arrangement creates mechanical advantage that reduces the force and time required for adjustment, thereby improving productivity without significantly increasing device complexity.
Data Source
AI summary
A patient support apparatus comprises a base, a support frame, and a patient support deck. The patient support deck comprises articulating deck sections, such as a leg section and a foot section pivotally coupled to the leg section. A support link is arranged to support the foot section relative to the support frame. A leg section actuator is configured to move the leg section between a lowered position and one or more raised positions. A foot section adjustment device is configured to move the support link in order to move the foot section relative to the leg section. The support link has a first link end pivotally coupled to the foot section and a second link end slidably coupled to the support frame.