Prestressing Strand Separation Device with Offset Cutting Edges
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Solution Overview
Problem
Existing methods for cutting prestressing strands in prestressed concrete structures, such as wind turbine towers, are inefficient due to sparking, smoke production, and the difficulty in cutting multiple strands simultaneously at the same height, leading to time-consuming processes and increased risk of corrosion.
Innovation Solution
A tension cord cutting device with multiple closely spaced lead-through openings and a cutting body with offset cutting edges allows for simultaneous shearing of prestressing strands without unbundling, ensuring uniform cutting and reduced wear, while the cutting body is guided to maintain a constant cutting force and prevent deflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional strand cutters are used to cut individual strands, then the strands can be separated, but the process becomes time-consuming and requires unraveling the bundle
Solution Approach 1:
The patent combines multiple cutting edges (first, second, and third cutting edges) into a single cutting tool that can simultaneously cut multiple prestressing strands at different positions. This merging of cutting functions into one integrated tool allows the bundle to be separated in a single operation rather than requiring sequential cutting of individual strands, thereby dramatically improving productivity and reducing time loss.
Solution Approach 2:
The cutting tool is segmented into multiple cutting edges positioned at different locations, with each cutting edge responsible for cutting a specific strand or group of strands. This segmentation allows simultaneous cutting action across multiple strands while maintaining the integrity of the cutting tool itself, resolving the contradiction between cutting speed and time efficiency.
2Productivity
If conventional cut-off machines are used to cut through the bundle, then all strands can be cut simultaneously, but strong sparking and smoke development occur
Solution Approach 1:
The patent replaces the conventional mechanical cut-off machine that causes sparking and smoke with a shearing-based cutting mechanism. The cutting edges are designed to shear the prestressing strands through a sliding motion rather than through high-speed mechanical impact or thermal cutting. This substitution of the cutting mechanism eliminates the harmful sparking and smoke generation while maintaining the ability to cut all strands simultaneously.
Solution Approach 2:
The cutting process parameters are changed from high-speed impact cutting to controlled shearing motion. The cutting edges move in a sliding motion relative to the strands, changing the cutting mechanism from impact-based to friction-based shearing. This parameter change reduces harmful effects while maintaining cutting effectiveness.
3Ease of operation
If strands are unraveled for individual cutting, then cutters can be attached, but a large distance from the anchor is required and cutting at uniform height becomes impossible
Solution Approach 1:
The patent merges multiple cutting functions into a single integrated cutting tool with multiple cutting edges positioned at specific geometries. This unified tool can engage multiple strands simultaneously at their natural bundle configuration near the anchor, eliminating the need to unravel the bundle. The tool's design ensures all strands are cut at a uniform height while maintaining ease of operation close to the anchor point.
Solution Approach 2:
The cutting tool is designed with cutting edges positioned in three-dimensional space to match the spatial arrangement of the prestressing strands in the bundle. By adapting the tool's geometry to the bundle's configuration, the patent enables cutting at uniform height without unraveling, solving the contradiction between operational accessibility and cutting precision.
4Productivity
If multiple cutting edges are used to cut all strands simultaneously, then productivity increases, but the cutting force required becomes excessively high
Solution Approach 1:
The patent applies partial action by designing the cutting process so that not all cutting edges engage the strands simultaneously with full force. Instead, the cutting edges are positioned and timed to engage strands in a sequence that distributes the cutting force, with each cutting edge performing the cutting action on its assigned strand(s) at an optimal moment during the sliding motion, thereby reducing the peak force requirement while maintaining simultaneous cutting capability.
Solution Approach 2:
The cutting tool employs dynamic motion where the cutting edges slide along the strands during the cutting process. This dynamic sliding motion allows the cutting force to be applied progressively rather than as a static impact, reducing the peak force required. The cutting edges move in coordination with the strand positions, enabling simultaneous cutting with reduced force demands through controlled dynamic action.
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 enables efficient, simultaneous cutting of multiple prestressing strands at the same height, reducing wear and maintaining a consistent cutting force, thereby improving safety, reducing time, and minimizing corrosion risks.
Implementation Method 1
the cutting body (29) has a first cutting edge (43a), a second cutting edge (43b) and a third cutting edge (43c) for separating prestressing strands (101) from one another by shearing
Implementation Method 2
The cutting body (29) is coupled to a piston (35) by means of a screw connection (33). The piston (35) is arranged in a piston chamber (37) and can be actuated hydraulically
Data Source
Figure 1
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AI summary
One embodiment proposes that the apparatus has a housing, a cutting body arranged within the housing, and a plurality of passage openings corresponding to the plurality of stranded tensioning wires, which extend through the housing, wherein the passage openings are each penetrated by a slot adapted to receive the cutting body, and the cutting body has one or more cutting edges and is drivable in the housing movably in a cutting direction relative to the passage openings in such a way that the cutting edge or edges completely transit through the passage openings.