Friction Pad Hold Open Rod for Fluid Leakage
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Solution Overview
Problem
Existing door closers using pneumatic or hydraulic dampeners for hold open rods face issues with fluid leakage and frequent maintenance due to worn seals and o-rings.
Innovation Solution
A hold open rod system utilizing a telescoping design with friction pads between an outer and inner tube, providing damping resistance through frictional engagement, eliminating the need for fluid-based dampening and reducing maintenance requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If pneumatic or hydraulic dampeners are used to control door closure, then door closure speed control is improved, but fluid leakage and seal wear occur requiring frequent maintenance
Solution Approach 1:
The patent replaces the fluid-based pneumatic or hydraulic dampening system with a solid friction-based dampening system. The friction pad pressed against the rod surface provides damping force through dry friction, eliminating seals, o-rings, and fluid containment components that are prone to leakage and wear. This mechanical substitution maintains door closure speed control while dramatically improving reliability and reducing maintenance frequency.
Solution Approach 2:
The patent extracts and removes the fluid containment system (cylinders, seals, o-rings, hoses) from the dampening mechanism. By taking out these problematic components and replacing them with a simple friction pad-rod interface, the system eliminates the sources of leakage and wear while retaining the essential dampening function for door closure speed control.
2Reliability
If friction pads are used for dampening, then maintenance requirements are reduced, but damping consistency may be affected by wear
Solution Approach 1:
The patent incorporates a spring mechanism that dynamically adjusts the friction pad's pressing force against the rod. As the friction pad wears during operation, the spring automatically compensates by increasing its compression and maintaining consistent normal force on the pad. This dynamic adjustment ensures that the damping force remains stable and consistent throughout the pad's service life, addressing the potential issue of damping inconsistency due to wear.
Solution Approach 2:
The spring-loaded mechanism provides self-adjusting functionality where the system automatically compensates for friction pad wear without external intervention. The spring continuously adapts its force to maintain optimal friction contact, allowing the dampening system to self-regulate and maintain consistent performance throughout the pad's operational lifespan, thereby reducing maintenance requirements.
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 system effectively controls door closure speed and maintains the door open state with reduced maintenance needs, as the friction pads provide consistent resistance without fluid leakage, enhancing reliability and longevity.
Implementation Method 1
a friction pad captured between the lock body and the outer surface of the inner tube
Data Source
AI summary
A hold open rod is provided. The hold open rod includes an outer tube, a lock body connected to the outer tube, an inner tube, slidingly disposed within the outer tube and lock body, the inner tube having an outer surface, and a friction pad captured between the lock body and the outer surface of the inner tube. A method for damping movement of a telescoping rod is also provided. The method includes attaching the locking body to an outer tube, configuring the outer tube and the inner tube to move with respect to each other in a telescoping manner, fitting a damper between an outer diameter of an inner tube and a locking body, and fitting the damper to frictionally engage the outer diameter of the inner tube and the locking body.