Toggle Lever Screw Tensioning for Large Bolts Without Hydraulics
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Solution Overview
Problem
Existing methods for tensioning large screws, such as hydraulic and mechanical wedge mechanisms, face challenges in applying precise torque and force, leading to potential damage and safety risks due to high compression energy release and limited applicability for large screws.
Innovation Solution
A device utilizing a toggle lever mechanism to displace a screw pulling member relative to a part to be tightened, eliminating the need for hydraulic fluid and enabling precise force multiplication, allowing for tensioning of screws up to M40 without a hydraulic system, thereby enhancing user safety and simplifying maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If hydraulic screw tensioning devices are used, then high tensioning force can be applied to screws, but high compression energy is stored in the hydraulic oil and sudden release may lead to serious safety dangers
Solution Approach 1:
The patent removes the hydraulic system entirely from the tensioning device, extracting the source of compression energy storage. Instead of using hydraulic fluid under high pressure, the invention employs a purely mechanical linkage system that applies tensioning force without accumulating dangerous compression energy in a fluid medium.
Solution Approach 2:
The patent replaces the hydraulic system with a mechanical linkage system. The mechanical components transmit force through rigid connections and levers, eliminating the need for compressible hydraulic fluid and associated high-pressure pumps and hoses, thereby removing the safety hazard while maintaining tensioning capability.
2Force
If mechanical wedge mechanism screw tensioning devices are used, then a relatively high tensioning force can be applied by a relatively small actuator screw, but the force/stroke conversion is constant which limits the size of screws that can be tensioned
Solution Approach 1:
The patent employs a dynamic mechanical linkage system where the force/stroke conversion ratio can vary during operation. The linkage geometry changes as components move through their range of motion, allowing the system to adapt to different screw sizes and tensioning requirements, unlike the fixed ratio of wedge mechanisms.
Solution Approach 2:
The mechanical linkage system is designed to be universally applicable to various screw sizes including large screws (M35, M36, M40 and above). The system can adjust its mechanical advantage through the movement of linkage components, making it versatile for different applications rather than being limited to specific screw dimensions.
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 toggle lever mechanism provides accurate and high force multiplication, enabling safe and efficient tensioning of large screws without hydraulic systems, reducing operational costs and improving safety by eliminating the need for high-pressure pumps and hoses.
Implementation Method 1
the force applied by the actuator screw is multiplied by force/stroke conversion. Thus, a relatively high tensioning force can be applied on the screw to be tightened by means of a relatively small dimensioned actuator screw
Implementation Method 2
Based on the angle of the wedge mechanism relative to the material axis of the screw, the force applied by the actuator screw is multiplied by force/stroke conversion
Data Source
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AI summary
The present invention pertains to a device (1) for tensioning a screw (3), containing a screw pulling member (2) comprising an engagement section (20) for engagement with a thread of a screw (3) to be tensioned, wherein a toggle lever mechanism (4) for displacing the screw pulling member (2) relative to a part to be tightened (5).