Outer-Ring Spring Mechanism for Adjustable Deflection
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Solution Overview
Problem
Existing spring expansion/compression mechanisms face issues such as high stress on cams leading to failure, difficulty in downsizing due to cam diameter increase, and inability to adjust deflection amounts.
Innovation Solution
A spring expansion/compression mechanism using an outer ring, wire, and outer-ring drive mechanism with a motor and speed reducers to control rotary power transmission and interruption, allowing for adjustable deflection and reduced stress on components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cam mechanism is used to unwind the spring, then the spring can be unwound with stored energy, but great force is applied to the cam causing it to be susceptible to failure
Solution Approach 1:
The mechanism segments the spring unwinding process into two distinct phases: compression phase (motor drives outer ring to compress spring) and expansion phase (spring freely expands to drive the arm). This segmentation allows the cam to be eliminated entirely, as the spring directly drives the mechanism during expansion without requiring a cam to convert rotational to linear motion, thereby eliminating the high force concentration on the cam.
Solution Approach 2:
The cam component is completely extracted from the mechanism. Instead of using a cam to control the spring's expansion and convert rotational motion to linear motion, the invention allows the spring to expand freely and directly drive the arm through the wire and outer ring connection, eliminating the need for a cam and its associated high-stress problems.
2Adaptability or versatility
If the cam diameter is increased to accommodate spring deflection, then the spring deflection can be handled, but the device becomes difficult to downsize
Solution Approach 1:
The mechanism dynamically adjusts the outer ring's position along the wire to accommodate varying spring deflection amounts. The outer ring can be positioned at different locations on the wire based on the required deflection, allowing the same mechanism to handle different spring specifications without requiring a larger fixed cam diameter. This dynamic positioning enables compact design while maintaining adaptability.
Solution Approach 2:
The mechanism changes the geometric parameters of the system by allowing the outer ring to be positioned at different locations on the wire, effectively changing the lever arm length and mechanical advantage. This parameter change allows the mechanism to accommodate different spring deflection amounts without increasing the overall device size, as the same compact structure can operate with different effective radii depending on the outer ring position.
3Adaptability or versatility
If a fixed cam mechanism is used, then the spring can be unwound, but the deflection amount of the spring cannot be adjusted
Solution Approach 1:
The mechanism incorporates dynamic adjustability through the outer ring's movable position on the wire. The outer ring can be repositioned along the wire to change the effective lever arm and mechanical advantage, allowing adjustment of the spring deflection amount. This dynamic feature is achieved through a simple structure where the outer ring can slide or be repositioned on the wire, adding minimal complexity while providing significant adaptability.
4Volume of moving object
If the cam diameter is reduced to downsize the device, then the device becomes compact, but the spring deflection capability is reduced
Solution Approach 1:
The mechanism compensates for the reduced outer ring radius (compact design) by changing the effective lever arm length through the wire configuration and outer ring position. Even with a small outer ring radius, the wire can be configured to provide sufficient mechanical advantage, and the outer ring can be positioned to optimize the lever arm length. This allows compact device size while maintaining spring deflection capability through parameter optimization rather than increasing physical dimensions.
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 mechanism reduces failure risk and enables downsizing while allowing precise control over spring deflection, enhancing reliability and compactness.
Implementation Method 1
a spring that is connected to the outer ring via the wire and is compressed when the wire is wound around the outer ring
Data Source
AI summary
A spring expansion/compression mechanism (SM) includes an outer ring (OR), a wire (WR), a spring (SP), and an outer-ring drive mechanism (RPT). The wire (WR) is connected to the outer surface of the outer ring (OR). The spring (SP) is connected to the outer ring (OR) via the wire (WR). The spring (SP) is compressed when the wire (WR) is wound around the outer ring (OR). The outer-ring drive mechanism (RPT) comes into close contact with the outer ring (OR) to transmit rotary power to the outer ring (OR). The outer-ring drive mechanism (RPT) releases the outer ring (OR) from the close contact to cause the outer ring (OR) to freely rotate.