Flared Cup Pipe Grooving for Low-Torque End-Groove Precision
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Solution Overview
Problem
Existing roll grooving machines face challenges in accurately producing circumferential grooves in pipe elements with precise tolerances, often resulting in flare and requiring complex designs with significant torque and low production rates, necessitating simpler and faster methods for cold working pipes with reduced operator involvement.
Innovation Solution
A device comprising a pinion, carriage, cup, and cam bodies with specific surface profiles and a gear system that allows for precise rotation and engagement with the pipe element, minimizing torque and enabling faster groove formation with improved accuracy and reduced operator intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If roll grooving machines are used to cold work pipe elements, then circumferential grooves can be formed, but the production rate is low and significant torque is applied
Solution Approach 1:
The grooving process is divided into multiple passes with progressively deeper groove depths. The cam mechanism applies force in incremental steps rather than attempting to form the complete groove in a single high-torque operation, thereby reducing the power requirement while maintaining productivity.
Solution Approach 2:
The cam mechanism operates periodically, engaging the pipe element at specific points during rotation to apply grooving force only when needed. This periodic action reduces average torque requirements compared to continuous force application, while the rotational motion maintains production rate.
2Manufacturing precision
If roll grooving machines are used to impress circumferential grooves, then grooves can be formed, but the groove radius precision within tolerance range is difficult to achieve
Solution Approach 1:
The cam mechanism is designed with a predetermined groove depth that is built into the cam profile itself. This self-contained design automatically ensures consistent groove radius precision without requiring external actuators or operator adjustments, achieving high manufacturing precision while keeping the device relatively simple.
Solution Approach 2:
The groove radius precision is achieved by carefully controlling the cam profile geometry and the rotational speed of the pipe element. By optimizing these parameters, the device achieves consistent groove dimensions within tolerance ranges without adding complex control systems.
3Productivity
If circumferential grooves are impressed near the end of pipe elements, then grooves can be formed, but the end region expands in diameter causing flare
Solution Approach 1:
The device incorporates a flare control mechanism that applies a counteracting force to prevent the natural flaring that occurs during grooving near pipe ends. This preliminary anti-action counterbalances the expansive forces, maintaining pipe end diameter consistency while allowing grooving to proceed near the pipe end.
Solution Approach 2:
The cam mechanism applies grooving force locally at the groove formation point rather than distributing force along the entire pipe length. This localized action minimizes the impact on the pipe end diameter while still achieving effective grooving near the pipe end, thereby maintaining manufacturing precision.
4Ease of operation
If prior art roll grooving machines are used, then grooves can be formed, but operator adjustment is required to achieve desired groove radius
Solution Approach 1:
The cam mechanism is designed with a fixed groove depth profile that automatically ensures accurate groove radius without requiring operator intervention. The device serves itself by maintaining consistent groove dimensions through its inherent mechanical design, eliminating the need for operator adjustments while preserving manufacturing precision.
Solution Approach 2:
The device incorporates mechanical feedback through the cam-follower interaction that automatically compensates for variations in pipe element dimensions. This feedback mechanism ensures consistent groove radius accuracy without requiring active operator control or adjustment.
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 device efficiently forms circumferential grooves with minimal torque application, achieving precise dimensions and reducing flare, thereby enhancing production rates and simplifying the design and operation of pipe grooving processes.
Implementation Method 1
A cup spring may act between the cup and the pinion to bias the cup away from the pinion
Implementation Method 2
A stop spring may act on the pipe end stop and to bias the pipe end stop away from the pinion
Implementation Method 3
The inner surface has a first diameter located distal to the pinion and a second diameter located proximate to the pinion. The first diameter is larger than the second diameter. In a specific example embodiment the sidewall may have a conical inner surface
Data Source
AI summary
A pipe grooving device has a flared cup which surrounds a pipe end stop. The cup and the pipe end stop are mounted on a fixed pinion about which a carriage rotates. The carriage carries geared cams which engage the pinion and rotate synchronously when the carriage rotates relatively the pinion. The cams engage a pipe element received by the cup and form a circumferential groove in the pipe element. The cup and the pipe stop move independently of one another axially along a pinion shaft to actuate rotation of the carriage. The flared cup accommodates dimensional pipe diameter tolerances and mitigates pipe flare and maintains pipe roundness during the grooving process.