Delay Return Gas Spring with Movable Seal Throttling
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Solution Overview
Problem
Conventional gas springs do not effectively manage the return stroke force, leading to potential damage or premature wear in applications like sheet metal stamping, as they maintain full force throughout the return stroke, which can cause sudden impact and reduce the lifespan of components.
Innovation Solution
A dual-chamber gas spring design with a movable seal that throttles gas flow between primary and secondary chambers during the return stroke, reducing the net force and velocity of the piston, thereby cushioning the final portion of the return stroke and preventing sudden impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional gas spring design is used, then the gas spring can maintain full force throughout the return stroke, but this causes sudden impact and premature wear of components
Solution Approach 1:
The gas spring is divided into two separate chambers: a primary chamber that maintains constant pressure and a secondary chamber that compresses during the return stroke. This segmentation allows different portions of the return stroke to have different force characteristics, eliminating the sudden impact at the end while maintaining sufficient force for most of the stroke.
Solution Approach 2:
The secondary chamber is designed to compress in advance during the return stroke, creating a cushioning effect before the piston reaches the end of its travel. This pre-compression of the secondary chamber gas absorbs the impact energy gradually, preventing sudden shocks to the components.
2Object-generated harmful factors
If a dual-chamber design with movable seal is used, then the net force and velocity are reduced during return stroke, but the device complexity increases
Solution Approach 1:
The secondary chamber is nested within the primary chamber structure. The piston rod passes through the primary chamber to reach the secondary chamber, and the movable seal is integrated into the piston assembly. This nested arrangement reduces the overall structural complexity compared to having two completely separate chambers.
Solution Approach 2:
The movable seal serves multiple functions: it separates the primary and secondary chambers, allows controlled gas flow between chambers during the return stroke, and maintains pressure differential. This multi-functionality reduces the need for additional separate components, simplifying the overall device structure.
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-chamber design reduces the net force and velocity of the piston during the return stroke, extending the life of components and improving operational efficiency by avoiding sudden stops, thus reducing wear, noise, and vibration.
Implementation Method 1
permit gas in the secondary chamber to be compressed in response to movement of the piston toward its extended position
Implementation Method 2
The seal is relatively movable between an open position permitting free flow of gas through the at least one passage to a closed position at least partially restricting gas flow through the at least one passage
Data Source
AI summary
A delay return gas spring including a piston at least partially received in a cylinder for reciprocation between extended and compressed positions over a cycle including a compression stroke and a return stroke. A seal disposed between the cylinder and the piston separates a primary chamber on one side of the seal from a secondary chamber on another side of the seal during a portion of the cycle. A passage communicates with the secondary chamber and with the primary chamber. The seal is relatively movable between an open position permitting free flow of gas through the passage to a closed position at least partially restricting gas flow through the passage so as to permit gas in the secondary chamber to be compressed in response to movement of the piston toward its extended position, thereby reducing a net return force on the piston and decreasing a velocity of the piston.