Saw Cord Loop Splice Design for Uniform Bending Stiffness
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Solution Overview
Problem
Existing methods for closing saw cord loops into multi-loop saw machines face challenges such as uneven wear, increased bending stiffness, and time-consuming processes, leading to reduced performance and efficiency, particularly in maintaining the integrity of the steel cord and saw beads during operation.
Innovation Solution
A method involving a short splice length with flattened and circumferentially oriented outer strand tips, allowing for easy bead shifting and injection molding, while maintaining the bending, torsion, and tension properties of the saw cord, using a specific arrangement of abutments and core strand positioning to minimize distortion and ovalization of beads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the steel cord is closed into a loop using a mechanical closure, then the connection is simple to make, but the bending stiffness becomes non-uniform causing beads to enter the cut differently and leading to ovalisation
Solution Approach 1:
The patent applies local quality by creating a splice connection where the outer strands are untwisted and laid parallel over a specific splice length, while the core strand continues twisted. This localized structural modification in the connection zone ensures uniform bending stiffness throughout the loop, preventing bead ovalisation while maintaining ease of manufacture through a standardized splicing procedure
2Loss of time
If the connection is made with traditional splicing methods, then the manufacturing time is reduced, but the breaking load deteriorates at the connection point
Solution Approach 1:
The patent applies preliminary action by pre-untwisting the outer strands and laying them in parallel position before making the connection. This preparatory arrangement allows for a quick splice operation while maintaining the structural integrity and breaking load of the steel cord, as the strands are already positioned optimally for load distribution
3Reliability
If the diameter of the steel cord increases at the connection, then the connection can be made more robustly, but it becomes difficult to shift beads over the connection before injection
Solution Approach 1:
The patent applies parameter changes by controlling the diameter of the steel cord at the connection point to not exceed the diameter outside the connection. This is achieved by laying the outer strands parallel without adding excessive bulk, allowing beads to be easily shifted over the connection before injection while maintaining connection robustness through proper strand arrangement and tensioning
Data Source
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AI summary
Loop saw cord loops are more and more used on multi-loop saw machines for the slabbing of natural or artificial stone. Closing the steel cord (100) is a critical operation during the manufacture of the saw cord loop as the saw beads (102) threaded on the steel cord (100) must be able to glide over the splice (3) without obstruction in order to allow automation of the injection moulding process. To enable this, the inventors propose to form the tips (112) of abutting outer strand (306) ends in the splice (3) in a specific manner. In addition, the splice (3) also has an influence on the useful life time of the saw cord loop. The inventors have observed that it not only suffices that the splice (3) where the saw cord is closed withstands the tensile stresses during use, but the splice (3) must also have a bending stiffness and a torsional behaviour that does not substantially deviate from that of the saw cord outside of the splice (3). In order to reach that objective specific splicing patterns are disclosed that result in a saw cord loop wherein the splice (3) is not discernible from the remainder of the loop in terms of tension, bending or torsion behaviour.