Weft Yarn Cutting Device with Rotatable Detaining Element
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Solution Overview
Problem
Existing devices for cutting weft yarn on weaving looms are bulky, require complex drives and control units, and have variable clamping forces that depend on yarn properties, making them unsuitable for double-face weaving looms and inconsistent in releasing tension.
Innovation Solution
A compact device with a non-resilient rotatable detaining element driven by a spring force, which rotates from a detaining position to a non-detaining position under tensile force, allowing for precise control of the cutting process without additional drives or control units, independent of yarn properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an elastically deformable resilient clamping body is used to detain weft yarn, then the yarn can be clamped between the clamping surface and the clamping body, but the device becomes bulky and takes up considerable space on the weaving loom
Solution Approach 1:
The invention changes the fundamental parameter of the clamping body from elastic/resilient material to a rigid structure with adjustable clamping force. Instead of relying on the inherent elasticity of a deformable body, the invention uses a rigid clamping body where the clamping force is controlled by an adjustable clamping element that can be positioned at different locations, thereby providing reliable yarn detention without requiring a bulky resilient structure
Solution Approach 2:
The invention introduces dynamic adjustability to the rigid clamping body through an adjustable clamping element that can be moved to different positions. This allows the clamping force and clamping location to be dynamically adapted to different yarn types and requirements, replacing the static elastic deformation of a resilient body with a dynamically adjustable rigid structure
2Adaptability or versatility
If a resilient clamping body is used, then the clamping force adapts to yarn properties, but the clamping force shows significant variations and cannot be controlled or accurately regulated
Solution Approach 1:
The invention provides dynamic control over clamping force through an adjustable clamping element that can be positioned at different locations on the clamping body. This allows precise regulation of clamping force to achieve consistent yarn detention, replacing the uncontrolled elastic variation of resilient materials with a mechanically adjustable system
Solution Approach 2:
The invention changes the control mechanism from passive elastic adaptation to active mechanical adjustment. By varying the position of the adjustable clamping element, the clamping force parameter can be precisely controlled and standardized, ensuring consistent yarn detention across different yarn types while maintaining adaptability
3Adaptability or versatility
If the clamping force varies significantly depending on yarn properties, then the tensile force at which the yarn breaks free from the clamp varies, but this reduces the reliability of the cutting device
Solution Approach 1:
The invention introduces dynamic adjustability to standardize the clamping force across different yarn properties. The adjustable clamping element can be positioned to provide consistent clamping pressure, ensuring that the tensile force required to break free the yarn from the clamp remains constant and predictable, thereby improving cutting operation reliability
Solution Approach 2:
The invention implements a feedback mechanism where the adjustable clamping element position can be optimized based on yarn properties to achieve consistent clamping force. This allows the system to adapt to different yarn types while maintaining reliable and repeatable cutting performance through controlled feedback on clamping pressure
4Loss of substance
If the device is arranged as closely as possible to the fabric edge to prevent yarn loss, then there is limited space available, making it impossible to accommodate a bulky clamping device
Solution Approach 1:
The invention fundamentally changes the volume parameter of the clamping device by replacing a bulky resilient clamping body with a compact rigid structure. This volume reduction enables the device to be positioned close to the fabric edge, minimizing weft yarn loss while maintaining effective yarn detention functionality
Solution Approach 2:
The invention uses dynamic adjustability of the clamping element to achieve effective yarn detention in a compact form factor. The adjustable mechanism allows the device to maintain proper clamping function despite the reduced space available when positioned near the fabric edge, preventing yarn loss without requiring excessive device volume
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 device is more compact, suitable for double-face weaving looms, and provides consistent tensile force for cutting weft yarn, reducing yarn loss and ensuring reliable operation across different yarn types.
Implementation Method 1
a spring element which exerts a spring force on the detaining element and forces it to its detaining position
Implementation Method 2
under the influence of a tensile force on the detained yarn, to rotate counter to said spring force to a non-detaining position
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The present invention relates to a device for cutting off weft yarn (27) during successive weaving cycles, comprising a cutting element (1) and a rotatable detaining element (2c), (13) which is forced to a detaining position by a spring force in order to detain the yarn and can rotate, under the influence of a tensile force exerted by a rapier on the detained yarn, counter to the spring force to a non- detaining position in which the yarn can be moved further towards the cutting element (1) in order to be cut. Such a device is efficient and can be made to be more reliable and more compact than existing devices. The invention also relates to a weaving loom provided with such a device.