Hydraulic Door Closer Sealing and Adjustable Backcheck Design
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Solution Overview
Problem
Hydraulic door closers face issues with fluid leakage due to non-smooth spindle surfaces, material mismatch between cap and housing, and lack of adjustable backcheck spring, leading to inefficiencies and user dissatisfaction.
Innovation Solution
The design incorporates a top cap opposite the spindle to prevent gravity-induced leakage, uses epoxy and O-rings for sealing, a rubber seal around the spindle, dual O-rings on valve stems, and steel caps matching the housing material, along with an adjustable spring for backcheck functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the spindle extends through the cap in prior designs, then the door closer structure is simple, but hydraulic fluid leaks due to gravity and non-smooth spindle surfaces
Solution Approach 1:
The sealing system is divided into multiple independent sealing elements: a first sealing element at the interface between the cap and housing, and a second sealing element around the spindle. This segmentation allows each sealing element to address specific leakage paths independently, improving overall reliability without requiring a completely complex integrated solution.
Solution Approach 2:
A first sealing element acts as an intermediary between the cap and housing, providing a reliable seal at the interface where leakage occurs. This intermediary sealing component addresses the specific problem of fluid leakage through the cap-spindle interface without requiring changes to the fundamental spindle extension design.
2Ease of operation
If adjustment valves are added to control hydraulic fluid flow, then door closing speed is adjustable, but leakage increases due to lack of sealing around valves
Solution Approach 1:
The cap serves multiple functions: it seals the housing interior, provides mounting for adjustment valves, and incorporates sealing elements to prevent leakage. By making the cap a multi-functional component, the design integrates valve sealing capability without requiring separate sealing mechanisms, thus maintaining adjustability while improving leakage resistance.
3Ease of manufacture
If aluminum end caps are used with steel housing, then manufacturing cost is reduced, but leakage occurs due to material mismatch
Solution Approach 1:
A first sealing element is introduced as an intermediary between the aluminum cap and steel housing interface. This sealing element compensates for the material mismatch and potential leakage issues, allowing the use of cost-effective aluminum caps while maintaining reliable sealing performance.
4Ease of operation
If a fixed spring is used for backcheck, then the structure is simple, but the spring force cannot be adjusted by users
Solution Approach 1:
The spring mechanism is made adjustable, allowing users to dynamically change the spring force according to their needs. This transforms a static, fixed spring system into a dynamic, adjustable one, enabling customization of backcheck force while maintaining reasonable structural simplicity through the use of standard adjustment mechanisms.
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 configuration significantly reduces fluid leakage and allows for adjustable spring force, enhancing the reliability and user customization of door closers.
Implementation Method 1
the rubber seal may compress the inner wall against the spindle to create a seal
Implementation Method 2
epoxy and an O-ring at the interface between the top cap and the housing of the door closer
Implementation Method 3
backcheck is feature on some door closers that prevents the door from crashing into the wall when it is opened suddenly
Data Source
AI summary
A hydraulic door closer is disclosed. The hydraulic door closer may include a top cap surrounded by an O-ring that is located at the top of the hydraulic door closer housing opposite a spindle to seal the hydraulic fluid within the housing. In addition to or in lieu of the top cap design, the door closer may include a locking washer to secure the valves to the housing; epoxy and an O-ring at the interface between the top cap and the housing of the door closer; use of a dual-walled rubber seal around the spindle; use of dual O-rings on each valve stems; use of caps that are made of the same material as the housing instead of aluminum and use of epoxy on the end caps; and/or use of backcheck with an adjustable spring.