Multi-Piece Bolt Head Structure for High-Torque Clamp Loads
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Solution Overview
Problem
Standard bolts fail to withstand high torques and preloads without failing at the weakest point where the shaft meets the bolt head, leading to potential shearing or popping off.
Innovation Solution
A multi-piece bolt design featuring a threaded shaft with a flared protrusion and a bolt head with a deformable body, where the bolt head is threadingly engaged onto the shaft, allowing for higher preload forces by distributing torsional stress over a larger area and utilizing a deformable component to absorb strain energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a standard bolt design is used, then the structure is simple and easy to manufacture, but the bolt fails at high torques due to stress concentration at the shaft-head junction
Solution Approach 1:
The bolt head is divided into two separate pieces: a rigid body that provides structural support and a deformable body that absorbs strain energy. This segmentation allows each piece to perform its specific function optimally, preventing failure at the shaft-head junction while maintaining overall structural integrity.
Solution Approach 2:
The bolt head combines rigid and deformable materials or structures. The rigid body provides mechanical strength and stability, while the deformable body absorbs energy through controlled deformation. This composite approach enables the bolt to withstand high torques that would cause failure in standard homogeneous bolts.
2Force
If torque is applied to a standard bolt, then the preload force is generated, but the torsional stress concentrates at the weakest point causing shearing or popping off
Solution Approach 1:
The deformable body is positioned in advance to absorb strain energy before failure can occur. During torque application, this deformable component deforms elastically or plastically, cushioning the stress concentration that would otherwise lead to shearing or popping off at the shaft-head junction.
Solution Approach 2:
The potential harmful stress concentration at the shaft-head junction is converted into a beneficial energy absorption mechanism. The deformable body intentionally deforms under torsional stress, transforming what would be a failure point into a protective feature that enhances reliability under high torque conditions.
3Strength
If higher torque is applied to increase clamp load, then the fastening strength improves, but the bolt head may shear or pop off in standard designs
Solution Approach 1:
By segmenting the bolt head into rigid and deformable components, the structure can safely handle higher torques. The rigid body maintains structural integrity while the deformable body absorbs the excess energy, enabling higher clamp loads without the harmful effects of shearing or popping off.
Solution Approach 2:
The bolt head's mechanical properties are changed by introducing a deformable body with different material characteristics than the rigid body. This parameter change allows the bolt to withstand higher torques and generate greater clamp loads while preventing failure through controlled deformation in the softer component.
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 multi-piece bolt design enables higher torque application without shearing or popping off, distributing torsional stress effectively and increasing the maximum clamp load, allowing for a 25% to 100% higher torque compared to standard bolts.
Implementation Method 1
a deformable body, where the bolt head is threadingly engaged onto the shaft, allowing for higher preload forces by distributing torsional stress over a larger area and utilizing a deformable component to absorb strain energy
Data Source
AI summary
A bolt includes a threaded shaft and a bolt head. The threaded shaft has a first end, a second opposing end, and an external thread. The first end includes a flared protrusion and the external thread is wrapped about the shaft and extends from the second opposing end to the flared protrusion. The bolt head includes an interior threaded bore for threadingly engaging the external thread of the threaded shaft, a front surface, and an opposing back surface having a recess configured to receive at least a portion of the flared protrusion of the threaded shaft therein.