Longitudinal Thread Rolling with Segmented Grooves
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Solution Overview
Problem
Existing methods for producing threads in elongate semi-finished products, such as anchor bolts, face challenges with uneven material displacement during longitudinal rolling, leading to uncontrolled deviations and potential weakening of the thread due to lateral material escape and burr formation, which are not addressed by considering the rotational symmetry of the thread.
Innovation Solution
The method involves shaping a cylindrical blank with longitudinal grooves and rolling a thread in the areas delimited by these grooves, where the distance between the groove bottoms and the axis is less than the thread root distance, and using rollers that rotate about an axis perpendicular to the direction of movement to form the thread, ensuring that the thread flanks adjoin the grooves and covering at least 80% of the circumference, with the rollers for thread rolling arranged to enclose the blank in a ring shape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If longitudinal rolling is used to produce threads, then the manufacturing process can be simplified, but material displacement becomes uneven leading to uncontrolled deviations and burr formation
Solution Approach 1:
The patent divides the thread rolling process into multiple segments by introducing grooves that partition the blank into separate regions. Each groove acts as an independent segmentation that controls material flow, preventing uncontrolled lateral displacement and burr formation while maintaining the simplicity of longitudinal rolling.
Solution Approach 2:
The patent applies local quality control by creating grooves at specific locations and depths relative to the thread root distance. This local modification of the blank structure ensures that material displacement is controlled precisely where needed, maintaining thread uniformity in the critical threading zones while allowing the overall process to remain a simple longitudinal rolling operation.
2Ease of manufacture
If longitudinal rolling is used without grooves, then the process is simpler, but material escapes laterally causing thread weakening
Solution Approach 1:
The grooves segment the material flow paths, creating discrete channels that guide material into the thread zones without lateral escape. This segmentation prevents material from deviating uncontrollably at the lateral edges, thereby maintaining thread strength while preserving the simplicity of the longitudinal rolling process.
Solution Approach 2:
The grooves act as intermediary structures that mediate between the simple longitudinal rolling action and the complex requirement for controlled material displacement. By introducing these intermediate groove features, the patent enables material to be directed precisely where needed without requiring complex rolling mechanisms, thus maintaining both process simplicity and thread strength.
3Manufacturing precision
If cross rolling is used to produce threads, then high quality threads with uniform radial dimensions are achieved, but the thread length is limited by the width of the rolled sections
Solution Approach 1:
The patent transitions from cross rolling (rolling perpendicular to the blank axis) to longitudinal rolling (rolling parallel to the blank axis), representing a dimensional change in the rolling direction. This dimensional shift allows the thread to extend along the entire length of the blank rather than being limited by the width of rolled sections, while the introduction of grooves maintains the necessary material control for high thread quality.
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
This approach allows for high-quality thread production with controlled material displacement, minimizing burr formation and thread weakening, while maintaining the thread's rotational symmetry and achieving uniform radial dimensions.
Implementation Method 1
shaping, in particular longitudinal rolling, of at least two longitudinal grooves in a blank and longitudinal rolling of a thread
Data Source
Figure 1~2
Figure 3~6
AI summary
The process according to the invention for producing a thread in an elongate semifinished product provides the following steps: at least two longitudinally running grooves (30) are formed, in particular longitudinally rolled, into a blank (50), and a thread is longitudinally rolled into the segments (31) which are delimited circumferentially by the grooves (30). A distance between the bases of the grooves (30) and an axis of the blank (50) is less than a distance between a base of the thread and the axis.