Variable-Length Spring Drafting Unit for Roving
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Solution Overview
Problem
Existing drafting systems for warping rovings in the textile industry face issues with inconsistent loading force transmission to the upper delivery rollers, leading to fluctuations in yarn quality due to non-concentric rotation of lower delivery rollers, causing relative movement and static friction between the leaf spring and cage element, which affects the guidance and stability of the output top rollers.
Innovation Solution
A drafting system employing a variable-length spring element, such as a helical compression spring, articulated at both ends and supported at bearing points, ensures a constant loading force on the upper delivery rollers, compensating for angular and positional changes, and is integrated with a connecting device and receiving device to maintain precise force transmission and prevent static friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a leaf spring is used to apply loading force to the cage element, then the upper delivery rollers can be pressed against the lower delivery rollers, but relative movement and static friction occur between the leaf spring and cage element due to non-concentric rotation, causing load fluctuations
Solution Approach 1:
The patent changes the physical state of the spring element from a rigid leaf spring to a flexible coil spring that can vary its length. This parameter change allows the spring to accommodate angular and positional changes of the cage element during operation, maintaining constant loading force without relative movement or static friction, thereby eliminating load fluctuations and ensuring consistent yarn quality
Solution Approach 2:
The patent makes the spring element dynamically adaptable by using a coil spring design that can change its length in response to operational conditions. This dynamic capability allows the spring to compensate for non-concentric rotation and maintain optimal contact between rollers without generating harmful friction forces, resolving the contradiction between applying sufficient loading force and maintaining reliability
2Ease of operation
If the lower delivery rollers rotate non-concentrically, then the cage element experiences angular and positional changes, but this causes relative movement between the spring and cage element leading to static friction and load fluctuations
Solution Approach 1:
The patent employs a spring element whose length can change in response to the cage element's angular and positional changes. This parameter flexibility allows the system to accommodate roller misalignment and non-concentric rotation without generating static friction or load fluctuations, as the spring continuously adjusts its configuration to maintain optimal force transmission
Solution Approach 2:
The spring element acts as an intermediary between the fixed support and the moving cage element. By using a coil spring that can vary its length, it mediates the connection in a way that absorbs angular and positional changes, preventing direct contact and static friction between rigid components, thereby eliminating harmful load fluctuations while maintaining ease of operation
3Power
If a rigid connection is used between the spring support and cage element, then force transmission is direct, but angular and positional changes cause static friction and guidance issues
Solution Approach 1:
The patent uses a spring element that changes its length as a parameter in response to operational conditions. This simple yet effective mechanism provides both direct force transmission and accommodation of angular/positional changes without requiring complex articulated linkages or multiple components, thus achieving high power transmission efficiency while avoiding excessive device complexity
Solution Approach 2:
The spring element is designed to automatically adjust its length in response to the cage element's movement, requiring no external control or complex mechanism. This self-adjusting capability provides both efficient force transmission and compensation for misalignment, achieving the desired performance without adding device complexity
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 ensures a consistent loading force on the delivery rollers, even with non-concentric rotation, preventing harmful load fluctuations and maintaining yarn quality by minimizing static friction, thus ensuring reliable and cost-effective operation of the drafting system.
Implementation Method 1
a variable-length spring element, such as a helical compression spring, articulated at both ends and supported at bearing points, ensures a constant loading force on the upper delivery rollers
Implementation Method 2
the upper rollers lie on the driven lower rollers with a predeterminable contact pressure and are driven by them in a frictionally engaged manner
Data Source
Figure 1
AI summary
The drafting unit (1) has pairs of input, middle and output rollers (2-4) which form delay zone and compression zone. The output upper rollers are connected to cage element (25) mounted in delivery top rollers (11u). The cage element is acted upon by a pressure element (15) in the direction of delivery lower rollers (11o). The pressure element has variable length spring element whose two ends (32,33) are pivotally supported on bearings, in longitudinal direction.