Drafting Roller Scraper with Obtuse Edge Angle
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Solution Overview
Problem
Existing cleaning devices for drafting rollers are not effective in reliably removing fibers that adhere to the outer circumferential surface, leading to inefficiencies in the drafting process.
Innovation Solution
A cleaning device with a scraper that extends along the width of the drafting roller, featuring a scraper edge portion with an obtuse angle relative to the tangent line, a projecting portion to prevent wear, and a stopper portion for visual abrasion indication, ensures reliable fiber removal and prolonged scraper life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cleaning blade angle is made to scrape off fibers effectively, then fiber removal reliability is improved, but the scraper edge portion becomes thin and weak
Solution Approach 1:
The patent applies parameter changes by optimizing the angle between the upstream-side outer surface and the tangent-line upstream portion to be an obtuse angle greater than 90 degrees (specifically 95-135 degrees). This angular parameter modification allows the scraper edge to maintain sufficient thickness and strength while still achieving effective fiber scraping performance, resolving the contradiction between reliability and strength.
2Productivity
If the scraper continuously contacts the drafting roller to remove fibers, then cleaning effectiveness is improved, but the scraper wears out quickly
Solution Approach 1:
The patent applies beforehand cushioning by providing a projecting portion on the scraper main-unit that contacts the drafting roller surface before the scraper edge portion. This projecting portion acts as a sacrificial element that wears first, cushioning the scraper edge from direct continuous contact and extending the overall scraper usable period while maintaining cleaning effectiveness.
3Reliability
If the scraper is pressed firmly against the drafting roller, then fiber removal is improved, but the scraper deforms and wears out faster
Solution Approach 1:
The projecting portion provides beforehand cushioning by absorbing initial contact wear and distributing pressing forces, preventing excessive deformation of the scraper main structure while maintaining sufficient pressing force for effective fiber removal.
Solution Approach 2:
The obtuse angle geometry of the scraper edge portion changes the mechanical parameters of contact, distributing pressing forces more favorably across the scraper structure, reducing stress concentration and deformation while maintaining cleaning effectiveness.
Data Source
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AI summary
A cleaning device (100) for a drafting roller (14a, 14b, 15a, 15b, 17a, 17b) includes a scraper (150; 150A; 150B) extending along a width direction of the drafting roller (14a, 14b, 15a, 15b, 17a, 17b) and contacting an outer circumferential surface of the drafting roller (14a, 14b, 15a, 15b, 17a, 17b). The scraper (150; 150A; 150B) is provided with, at an end portion on an upstream side in a rotational direction of the drafting roller (14a, 14b, 15a, 15b, 17a, 17b), a scraper edge portion (152) contacting the outer circumferential surface of the drafting roller. An angle (α) being formed by a tangent-line upstream portion (L) that is on a tangent line of the drafting roller (14a, 14b, 15a, 15b, 17a, 17b) passing a contact point (T) with the scraper edge portion (152) and extends from the contact point (T) toward the upstream side of the rotational direction of the drafting roller (14a, 14b, 15a, 15b, 17a, 17b), and by an upstream-side outer surface (152a) that is in an outer surface of the scraper edge portion (152) and is a surface facing the upstream side in the rotational direction of the drafting roller (14a, 14b, 15a, 15b, 17a, 17b), when viewed along an axial direction of the drafting roller (14a, 14b, 15a, 15b, 17a, 17b), is an obtuse angle.