Weft Gripping Mechanism for Shuttleless Looms
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Solution Overview
Problem
Conventional shuttle-less weaving machines face issues with weft thread tension control and yarn wastage due to rubbing between selvedge warp threads and grippers, leading to thread breakages and inefficiencies in weft insertion timing.
Innovation Solution
A Weft Gripping mechanism that uses a mechanical system to grip the weft thread before cutting, allowing precise control over tension and reducing yarn wastage by eliminating rubbing actions, with adjustable gripping force and timing for optimal fabric appearance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional false selvedge is used to grip the weft thread, then the weft thread is secured before cutting, but rubbing occurs between selvedge warp threads and gripper causing thread breakages
Solution Approach 1:
The invention extracts the harmful rubbing action by replacing the conventional false selvedge gripping mechanism with a dedicated weft gripping device mounted on the sley. This new mechanism grips the weft thread directly without involving selvedge warp threads, thereby eliminating the rubbing between selvedge threads and gripper that caused thread breakages.
Solution Approach 2:
The invention introduces an intermediary weft gripping mechanism that acts as a mediator between the weft insertion gripper and the cutting mechanism. This intermediary device secures the weft thread through a dedicated gripping action rather than through the selvedge warp threads, eliminating the harmful rubbing while maintaining the necessary tension and control.
2Reliability
If false selvedge timing is set early to secure weft thread, then weft is gripped before cutting, but excessive weft yarn wastage occurs due to imprecise timing
Solution Approach 1:
The invention replaces the timing-based false selvedge mechanism with a mechanically actuated weft gripping device mounted on the sley. This mechanical system provides precise control over the gripping action timing and position, eliminating the imprecise timing of conventional false selvedge that led to excessive weft yarn protrusion and wastage.
Solution Approach 2:
The invention changes the critical parameter of gripping timing from an early, imprecise false selvedge action to a precisely controlled mechanical gripping action synchronized with the weft insertion and cutting cycle. This parameter change enables exact control over weft protruding length, reducing wastage from 4% to 3%.
3Reliability
If conventional false selvedge mechanism is used, then weft thread is gripped, but tension control of weft thread is poor affecting fabric appearance
Solution Approach 1:
The invention extracts the weft gripping function from the false selvedge mechanism and places it in a dedicated weft gripping device on the sley. This separation allows for optimized tension control specifically for the weft thread, improving fabric appearance quality by providing consistent and controllable weft tension throughout the weaving process.
4Reliability
If selvedge warp threads are used to grip weft, then weft insertion is secured, but machine stoppages increase due to thread breakages
Solution Approach 1:
The invention introduces an intermediary weft gripping mechanism on the sley that mediates between the weft insertion gripper and the fabric selvedge. This intermediary device secures the weft thread during insertion without involving the selvedge warp threads, eliminating the thread breakages that caused machine stoppages and improving overall machine efficiency.
Data Source
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AI summary
The invention refers to a path breaking and pioneering effort to art a Weft Gripping mechanism for use on shuttle-less weaving machines. There is no such or similar device in existence today and the need for such a mechanism arises from the key points of disadvantages of the existing systems. With the advent of this Weft Gripping mechanism, the rubbing action between the weft insertion media and boundary selvedge threads is totally eliminated and so will be the breakages arising due to this rubbing. It not only facilitates precision timing of positive grip but also improves the gripping force exerted on the weft yarn and brings about a better tension control of the weft thread, which is known to be the key element for a better fabric appearance. This novel weft grip mechanism allows a more precision timing setting of weft grip, which in turn means exact or optimum weft protruding length, which obviously means lesser wastage of precious weft yarns.