Mechanical Bolt Tensioning Tool for Precise Clamp Load
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Solution Overview
Problem
Existing bolt tensioning methods, such as those using hydraulic tensioners, are slow and inconvenient, especially for smaller bolts, and introduce uncertainties in achieving precise clamping force due to varying friction in threaded joints.
Innovation Solution
A bolt tensioning tool with a bolt receiving element, nut socket, axle, threaded sleeve, and supporting sleeve, which applies an axial force and locks the bolt in an elongated state, allowing for precise clamp load application through a clever sequence of rotational movements and a resilient element to maintain tension.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If hydraulic tensioners are used for bolt tensioning, then precise clamping force can be achieved, but the process becomes slow and inconvenient
Solution Approach 1:
The patent replaces the hydraulic system with a purely mechanical screw-based tensioning mechanism. The axle with external thread and threaded sleeve with internal thread create a mechanical advantage system that generates axial force through rotation, eliminating the need for hydraulic pumps and fluid systems while achieving precise clamping force control
Solution Approach 2:
The tensioning tool is divided into separate functional modules: the axle for applying rotational motion, the threaded sleeve for converting rotation to axial movement, the supporting sleeve for bearing against the workpiece, and the nut socket for securing the bolt. This segmentation allows each component to be optimized independently and simplifies the overall mechanism
2Productivity
If torque is applied to bolt using power tools, then tightening can be achieved, but uncertainties exist regarding actual clamping force due to varying friction
Solution Approach 1:
The patent replaces torque-based tightening with direct axial tensioning. By applying force directly along the bolt's axis through the threaded mechanism, the system eliminates the influence of friction variables in the threads and under the nut head, achieving precise control of clamping force independent of friction conditions
Solution Approach 2:
The threaded sleeve acts as an intermediary mechanism between the rotational motion and the axial tensioning force. It converts the rotational input into controlled axial displacement, providing a predictable and repeatable force application that is independent of frictional variations in the joint
3Measurement precision
If axial tensioning force is applied to achieve desired elongation, then precise clamp load is obtained, but the tool becomes complex
Solution Approach 1:
The patent combines multiple functions into integrated components: the supporting sleeve both supports the workpiece and bears the reaction force, the nut socket both secures the bolt and allows rotational movement, and the threaded sleeve both converts rotation to axial motion and limits the elongation. This merging reduces the number of separate parts while maintaining precision
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 tool enables fast, precise, and user-friendly application of clamp load with reduced scatter, facilitating improved quality and handling of bolt tensioning, suitable for both small and large bolts.
Implementation Method 1
the axle comprising an external thread, a threaded sleeve arranged on the axle and having an internal thread adapted to cooperate with the external thread of the axle such that a relative rotational movement between the axle and the threaded sleeve result in a relative axial displacement between the axle and the threaded sleeve
Implementation Method 2
a resilient element adapted to provide at least said limited relative rotational movement, said resilient element engaging said supporting sleeve and said socket
Data Source
AI summary
A bolt tensioning tool is adapted to tension a bolt protruding from a workpiece, and includes a bolt receiving element adapted to be screwed onto the bolt, a nut socket adapted to receive a nut, an axle adapted to exert an axial force on the bolt receiving element, a threaded sleeve arranged to engage the axle and having an internal thread adapted to cooperate with an external thread of the axle such that a relative rotational movement therebetween results in a relative axial displacement between the axle and the threaded sleeve, a supporting sleeve coupled to the threaded sleeve and adapted to selectively bear against the workpiece, and a coupling adapted to connect the nut socket and the supporting sleeve, the coupling is a coupling allowing a limited relative movement between the socket and the sleeve.