Stepped Connecting Pin Link Mechanism Without Retaining Ring
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Solution Overview
Problem
The existing link mechanism experiences wear and loss of the retaining ring due to constant spring bias, leading to the link plate and rod potentially falling off the connecting pin.
Innovation Solution
A connecting pin with a larger-diameter portion, a medium-diameter portion, and a smaller-diameter portion is used, where the outer diameters and dimensions satisfy specific ratios, allowing the pin to securely hold the link portions without a retaining ring, enhancing durability and wear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a retaining ring is used to prevent the link plate and rod from falling off the connecting pin, then the link mechanism can maintain connection, but the retaining ring wears out due to constant spring bias load and may fall off
Solution Approach 1:
The patent removes the retaining ring from the system entirely. Instead of using a separate retaining ring component that is subject to wear, the connecting pin itself is designed with a head portion that extends beyond the link plate, providing inherent retention functionality. This extraction of the retaining ring eliminates the wear problem while maintaining the connection reliability.
Solution Approach 2:
The retention function is merged into the connecting pin structure itself. The head portion of the connecting pin is integrated to provide both the connection function (through the pin body) and the retention function (through the head extending beyond the link plate). This merging eliminates the need for a separate retaining ring and its associated wear issues.
2Strength
If a retaining ring is attached to the connecting pin to secure the link plate and rod, then the connection is maintained, but the retaining ring is subject to wear from spring bias and may fail
Solution Approach 1:
The patent extracts the retaining ring from the system and replaces it with the head portion of the connecting pin. This eliminates the harmful wear and friction that affected the retaining ring, while the connection strength is maintained through the integrated head design that prevents the link plate and rod from detaching.
Solution Approach 2:
The patent replaces the wear-prone retaining ring with a more durable integrating design where the head portion is part of the connecting pin itself. This effectively creates a 'permanent' retention solution rather than a disposable retaining ring that needs periodic replacement due to 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 prevents the link portions from falling off, improves wear resistance, and reduces friction loss, thereby maintaining the link mechanism's functionality and efficiency.
Implementation Method 1
a spring arranged between the first link portion and the second link portion... The spring biases the link plate and the rod in directions spaced apart from each other
Data Source
AI summary
A link mechanism includes: a first link portion including a first hole; a second link portion including a second hole; a rotary shaft of a rotating body attached to the first or second link portion; a spring arranged between the first link portion and the second link portion; and a connecting pin including: a larger-diameter portion located on the first link portion at a side opposite to the second link portion and the spring and having an outer diameter larger than an inner diameter of the first hole and an inner diameter of the second hole; a medium-diameter portion having an outer diameter smaller than that of the larger-diameter portion and at least partially located within the first hole; and a smaller-diameter portion having an outer diameter smaller than that of the medium-diameter portion and at least partially located within the second hole.