Pivot Joint Sealing With Toroidal Gaskets for Grease Retention
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Solution Overview
Problem
Pivot joints in mechanical structures face challenges in retaining lubricating grease while preventing dirt and debris contamination, leading to lubricant degradation and wear.
Innovation Solution
A pivot joint design incorporating resilient toroidal gaskets at each end of the bore, seated in circumferential recesses on the pivot pin or housing, forms a sealed interior to keep lubricant in and contaminants out, with an optional washer providing additional external sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If no barrier is provided in the pivot joint, then the structure remains simple and easy to manufacture, but lubricating grease leaks out and contaminants enter the joint
Solution Approach 1:
The patent uses flexible toroidal gaskets (O-rings) as thin film barriers to seal the pivot joint. These elastomeric gaskets are installed in circumferential grooves on the pin or housing, creating effective seals without adding complex mechanical structures. The gaskets prevent grease leakage and contaminant ingress while maintaining simplicity in the overall joint design.
2Duration of action of moving object
If lubricating grease is retained in the pivot joint without sealing, then the joint operates simply, but the lubricant degrades due to contamination with dirt and debris
Solution Approach 1:
The toroidal gaskets form flexible film barriers that create a sealed environment around the lubricant. This isolation prevents dirt and debris from contaminating the grease, thereby extending the lubricant's operating life and maintaining its protective properties throughout the pivot joint's service life.
Solution Approach 2:
The gaskets act as intermediary barriers between the lubricant and external contaminants. By positioning the gaskets at the interface between the internal lubricated environment and the external contaminated environment, they mediate the interaction and prevent harmful contaminants from reaching the lubricant.
3Loss of substance
If a seal is added to the pivot joint, then lubricant leakage is prevented, but the manufacturing complexity and assembly steps increase
Solution Approach 1:
The toroidal gaskets are simple elastomeric rings that can be easily manufactured and installed in circumferential grooves. Their flexible nature allows them to conform to slight variations in groove dimensions, making assembly tolerant and straightforward. The gaskets prevent grease leakage effectively while adding minimal complexity to the manufacturing and assembly processes.
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 design effectively extends the operating life of lubricant by preventing leakage and contamination, maintaining a clean internal environment within the pivot joint.
Implementation Method 1
a resilient toroidal gasket at each of the opposite ends of the housing located in the bore at axially spaced positions of the pivot pin
Implementation Method 2
lubricant in the form of lubricating grease is disposed at an interface defined between the pin and an interior surface of the bore so as to reduce friction at this interface and enable smooth pivotal movement
Data Source
AI summary
A pivot joint comprises a pivot pin mounted to a first member and a second member with a housing defining a bore receiving the pivot pin, thus forming a pivot axis for pivotal movement of one member relative to the other. A resilient toroidal gasket is provided at either end of the housing in the bore at axially spaced positions of the pivot pin, and a circumferential recess receives each gasket in fixed axial location along the pivot pin. The gasket spans radially of the pivot pin from a base of the recess and across a circumferential gap formed between an inner surface of the bore and an outer surface of the pin where lubricant is suitably received. Thus the gaskets form a sealed interior of the bore closed at either end by the respective gasket so as to maintain the lubricant therein and contaminants out.