Dual-Rate Gas Spring Assembly for Smooth Lift Force Transition
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Solution Overview
Problem
Existing spring systems in applications like medical imaging and automotive systems often require varying force levels during lift or descent procedures, posing challenges in providing reliable and smooth elevation transitions, especially with varying patient or load weights.
Innovation Solution
A dual-rate spring system comprising a higher force gas spring and a lower force gas spring, along with a damper assembly, positioned back-to-back to provide varying force assistance, where the damper smooths the transition between the two springs, ensuring consistent and safe operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single mechanical coil spring is used, then the structure is simple, but the force output cannot be adjusted at different stages of lift or descent
Solution Approach 1:
The patent divides the spring system into multiple segments - specifically a high-force spring and a low-force spring - that operate at different stages of the lift/descent procedure. This segmentation allows the system to provide different force levels at different positions, resolving the contradiction between adaptability and complexity by creating a modular multi-spring configuration.
Solution Approach 2:
The patent implements a dynamic spring system where the effective spring constant changes during operation. By using a damper assembly with a spring that transitions between compressed and extended states, the system dynamically adjusts its force output characteristics, providing high force when needed and low force at other times, thus achieving adaptability through dynamic behavior.
2Reliability
If multiple springs are used to provide varying force, then the force assistance is improved, but the transition between springs may cause instability
Solution Approach 1:
The patent introduces a damper assembly as an intermediary element between the high-force spring and low-force spring. This damper assembly includes a spring that acts as a mediator, providing a smooth transition between the two main springs during compression and extension. The intermediary damper prevents abrupt force changes, ensuring stable and reliable operation while managing the complexity of the multi-spring arrangement.
3Force
If higher force spring is used throughout, then lift force is sufficient, but the load on motion control device is excessive at higher elevations
Solution Approach 1:
The patent applies local quality by matching the spring force characteristics to the specific requirements at different elevations. The high-force spring provides sufficient lift force when needed (at lower elevations where more force is required), while the low-force spring operates at higher elevations where less force is needed. This localized optimization of force output reduces the overall load on the motion control device and minimizes energy loss.
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
The dual-rate spring system offers reliable and smooth lift and descent assistance, reducing the load on motion control devices, enhancing safety and efficiency by providing higher lift force at lower elevations and lower lift force at higher elevations, while minimizing wear and cost.
Implementation Method 1
a higher force gas spring comprising a first spring body and a first rod extending from the first spring body; a lower force gas spring comprising a second spring body and a second rod extending from the second spring body
Implementation Method 2
a damper assembly attached to the first rod or the second rod; the damper assembly comprises a damper spring, the damper spring having a force between the force of the lower force spring and the higher force spring to provide smoothing of the force transition
Data Source
AI summary
A dual-rate tandem spring system is described. The system may include a higher force spring and a lower force spring. The spring system may comprise gas springs. The spring system may be included in a table system to provide lift or descent assist of objects such as a patient. A damper may be installed in the spring system to provide smooth transition between lower and higher force springs.