Gripper Assembly Yarn Insertion Wear Reduction
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Solution Overview
Problem
Current gripper technologies in shuttle-less weaving looms face limitations in versatility, energy consumption, and yarn tension control, particularly with the negative exchange type switch mechanism causing interference with the warp, leading to wear and spare part costs.
Innovation Solution
A pair of grippers with innovative components, including a rocker pin with a wedge-shaped yarn gripping arm and a taker gripper with a flexible rod and elastic blade, ensures reliable grip, transport, and release of weft yarns across various types, using controlled friction and self-locking mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If special gripper opening hooks are used for positive switch inside the warp step, then the yarn transfer between grippers is actuated, but the hooks interfere with the warp and cause wear and costs for spare parts
Solution Approach 1:
The patent removes the special gripper opening hooks from the system entirely, transitioning from a positive switch mechanism that required these hooks to a negative switch mechanism that operates without them. This extraction eliminates the source of warp interference and wear while maintaining yarn transfer functionality through the negative exchange type switching mechanism.
Solution Approach 2:
The patent inverts the switching mechanism from positive (using active hooks to open and transfer yarn) to negative (using passive friction-based holding elements that release yarn through controlled friction). This inversion eliminates the need for interfering hooks while achieving reliable yarn transfer through the taker gripper's friction-based holding elements.
2Reliability
If fixed wedge type holding elements are used, then progressive locking by friction is achieved, but the structure is complex and wear occurs
Solution Approach 1:
The patent applies local quality by using holding elements with specifically engineered friction characteristics at the yarn contact points. The taker gripper's holding elements are designed with controlled friction properties that enable reliable yarn gripping and progressive locking without requiring complex overall structures. This localized friction control achieves high reliability with simpler mechanics.
3Adaptability or versatility
If conventional holding elements are used, then yarn is held between gripping elements, but friction causes wear and limits versatility with different yarn types
Solution Approach 1:
The patent implements dynamics by using elastic holding elements that can adapt their friction characteristics to different yarn types. The holding elements can dynamically adjust their grip force and friction properties based on the specific yarn being processed, enabling versatility across twisted, parallel, fancy, multi-filament, and metallic yarns while reducing wear through controlled, adaptable friction rather than fixed high-friction contact.
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 gripper assembly provides high reliability and versatility in handling a wide range of yarns, reducing friction and wear, and optimizing yarn insertion and release processes in shuttle-less weaving looms.
Implementation Method 1
controlled friction on the yarn and slide it between the gripping elements
Implementation Method 2
rocker pin with a wedge-shaped yarn gripping arm
Implementation Method 3
taker gripper with a flexible rod and elastic blade
Implementation Method 4
guide profiles which predispose the yarn lying between an abutment and a resilient rocker pin
Data Source
Figure 1~3
Figure 4~6
AI summary
A gripper assembly for inserting the weft yarn into looms without a shuttle, comprising a bringer gripper and a traction gripper. The bringer gripper comprises a main body (1) with a shaped end adapted to be fixed to a control element, a weft guide profile (2), a rocker arm (3) hinged on a rotation pin (4), a reaction spring (6) and a gripper pin (5) of the rocker lever (3), which is rotating about a vertical axis of the main body (1) of the gripper; the reaction spring (6) keeps the gripper pin (5) on one side and closes it at an opposite side to an inclined plane, so as to obtain an self-tightening condition. The traction gripper, which switches the yarn (7) in the center of the fabric with the bringer gripper, comprises a main body (10) with a shaped end, a central part, which includes a drive lever (12) for the opening or closing of a zone of gripping of the yarn (7), a longitudinally sliding rod (11), which has a slider (14) slidable in a hook-shaped portion 15), and an elastic blade (18) fixed to the slider (14), which opens simultaneously with the slider for releasing the yarn (7).