Dashpot Rib-and-Groove Piston Guidance for Compact Closure Damping
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Solution Overview
Problem
Existing dashpots for damping closing movements of closure systems face issues such as increased space requirements due to separate guiding elements, hydraulic fluid leakage, lack of thermal stability, and abrasiveness between fibre reinforced polymeric pistons and metal cylinder barrels.
Innovation Solution
The dashpot incorporates a rotation prevention mechanism with integrally formed ribs on the cylinder barrel and grooves on the piston, eliminating the need for a separate guiding element. Additionally, spacers made from high abrasion-resistant materials are interposed between the piston and cylinder barrel to prevent direct contact and reduce wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a separate guiding element is used to prevent piston rotation, then the piston rotation is effectively prevented, but the dashpot diameter and height increase
Solution Approach 1:
The guiding element is merged with the piston by integrally forming the grooves directly into the piston body. This eliminates the need for a separate guiding element and reduces the dashpot dimensions while maintaining the rotation prevention function through the interaction between the grooves and the cylinder barrel's inner surface.
2Ease of manufacture
If a cast moulded dashpot barrel is used, then manufacturing is simplified, but hydraulic fluid leakage occurs and thermal stability is poor
Solution Approach 1:
The manufacturing method of the dashpot barrel is changed from cast moulding to extrusion moulding. This parameter change in the manufacturing process eliminates hydraulic fluid leakage and improves thermal stability while maintaining ease of manufacture, as extrusion moulding allows for better material selection and structural control.
3Device complexity
If a fibre reinforced polymeric piston slides directly on the aluminium cylinder barrel, then the structure is simple, but wear occurs on the cylinder barrel
Solution Approach 1:
A coating layer is introduced as an intermediary between the fibre reinforced polymeric piston and the aluminium cylinder barrel. This coating layer, applied on the inner surface of the cylinder barrel, prevents direct contact and wear while maintaining the simplicity of the overall structure. The coating acts as a protective mediator that reduces friction and wear.
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
This design reduces the overall dimensions of the dashpot, enhances the reliability of the piston sliding motion, and improves thermal stability by avoiding direct contact between the piston and cylinder barrel, thus reducing wear and leakage issues.
Implementation Method 1
at least one spacer interposed between the cylinder barrel and the piston so as to avoid direct contact of the piston and the cylinder barrel
Implementation Method 2
mating screw threads configured to cooperate with one another so that upon a relative rotation between the cylinder barrel and the damper shaft the piston slides along the damper shaft along said longitudinal direction
Implementation Method 3
a closed cylinder cavity formed within the cylinder barrel and being filled with a volume of hydraulic fluid
Data Source
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AI summary
A dashpot (5) comprises: a cylinder barrel (17) extruded or broached from metal; a fibre reinforced polymeric piston (47) slidable within the cylinder barrel; a damper shaft (24) rotatably mounted within the cylinder barrel; and a motion converting mechanism for converting a rotational motion of the damper shaft in a sliding motion of the piston. The motion converting mechanism comprises: mating screw threads (58, 59) and a rotation prevention mechanism for preventing a rotation of the piston with respect to the cylinder barrel. The rotation prevention mechanism comprises: one or more longitudinally extending ribs (10) integrally formed with the cylinder barrel; one or more longitudinally extending grooves integrally formed with the piston on the outer surface thereof; and one or more spacers (50) interposed between the cylinder barrel and the piston so as to avoid direct contact of the piston and the cylinder barrel.