In-Line Tendon Shear for Flame-Free Post-Tension Cutting
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Solution Overview
Problem
Existing methods for cutting post-tensioning tendons in concrete structures are hazardous due to the use of open flames, which can cause fires, explosions, and damage to metal components, and require costly and time-consuming hot work permits.
Innovation Solution
An in-line strand cutter with a compact design, featuring a cylinder for linear force application, a gear train for rotational force translation, a nose piece with a blade assembly, and a clamp assembly, allowing for efficient cutting of tendons in-line with the tendon axis, reducing the risk of fire and metal damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional cutting torch is used to cut the tendon, then the cutting operation can be performed, but it creates fire or explosion hazards and may cause loss of temper of metal components
Solution Approach 1:
The patent replaces the thermal cutting system (torch with open flame) with a mechanical cutting system (hydraulic shear with blades). The hydraulic shear applies mechanical force directly to cut the tendon, eliminating the need for open flames and associated fire hazards while preventing thermal damage to metal components.
Solution Approach 2:
The patent employs a hydraulic system to generate the cutting force. A hydraulic cylinder drives a shear blade that mechanically cuts the tendon through pure mechanical action, replacing the thermal energy of a torch with hydraulic mechanical energy, thereby eliminating fire risks and thermal damage.
2Object-affected harmful factors
If a hydraulic shear is used to cut the tendon, then fire hazards are eliminated, but the device complexity increases compared to a simple torch
Solution Approach 1:
The hydraulic shear is designed to perform multiple functions: it can cut tendons at various positions, handle different tendon configurations (including in-line and angled cuts), and integrates both cutting and clamping functions in a single device, justifying its increased complexity through enhanced versatility and safety.
Solution Approach 2:
The patent employs a compact design where the shear blade, anvil, and hydraulic components are nested within a confined space. The movable shear blade fits within the housing, and the hydraulic cylinder is integrated into the same structure, reducing overall device footprint despite the increased functional complexity.
3Ease of operation
If an in-line cutting approach is used, then the device can access tight spaces, but the mechanical design becomes more challenging compared to right-angle cutting
Solution Approach 1:
The patent employs a movable shear blade that can be dynamically positioned along the tendon axis through hydraulic actuation. This dynamic positioning capability allows the blade to reach various cutting locations including tight spaces, while the hydraulic system automatically maintains proper alignment, reducing the burden on mechanical precision.
Solution Approach 2:
The patent introduces a guide mechanism or alignment feature that acts as an intermediary between the hydraulic actuator and the shear blade. This intermediary component ensures proper alignment of the cutting edge with the tendon axis, simplifying the mechanical design by decoupling the positioning and cutting functions.
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 in-line strand cutter provides a safer, more efficient, and cost-effective method for cutting post-tensioning tendons, eliminating the risks associated with open flames and reducing the need for hot work permits, while maintaining precision and versatility in cutting multiple strands and planes.
Implementation Method 1
a cylinder for applying linear force; a gear train for translating the linear force to rotational force
Data Source
AI summary
This application details a configuration for an in-line tendon shear, which may also be referred to as an in-line pocket shear. Exemplary embodiments may improve upon existing cutters and shears for tendons in post-tensioning operations by being advantageously more compact, efficient, can cut in multiple planes, such as horizontal and vertical planes, and may include additional other benefits. The in-line tendon shear has components that are aligned with a central axis of a tendon.