Pipe Grooving Die and Cam Layout for Low-Torque Groove Forming
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Solution Overview
Problem
Existing roll grooving machines face challenges in accurately and efficiently forming circumferential grooves in pipe elements with precise tolerances, often requiring complex designs, significant torque, and high operator involvement, while also dealing with flare issues near the pipe ends.
Innovation Solution
A device comprising a pinion, expanding die, and cam surfaces that rotate around the pipe element, with an actuator and gears to control the groove formation, minimizing torque and operator intervention, and using a die to precisely shape the groove.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If roll grooving machines are used to form circumferential grooves in pipe elements, then grooves can be formed to accept mechanical pipe couplings, but the process requires significant torque and has low production rates
Solution Approach 1:
The die is divided into multiple segments that can be independently actuated. Each segment can be forced toward the pipe element to form the groove, distributing the force application and enabling more efficient material displacement compared to a single rolling contact point.
Solution Approach 2:
Instead of rotating the pipe element under significant torque as in conventional roll grooving machines, the invention inverts the approach by using a stationary pinion and rotating the die segments around the pipe. This eliminates the need for high torque to rotate the pipe, as the die segments are directly actuated by cam mechanisms.
2Manufacturing precision
If conventional roll grooving machines are used, then grooves can be formed, but complicated designs with actuators and operator adjustments are required to achieve desired groove radius and tolerances
Solution Approach 1:
The cam mechanisms are designed with predetermined cam profiles that automatically control the radial movement of die segments. This self-service mechanism eliminates the need for external actuators and operator adjustments, as the cam geometry inherently ensures the desired groove radius and profile are achieved through the mechanical motion program embedded in the cam design.
Solution Approach 2:
The cam profiles are pre-designed with the exact geometry needed to produce grooves within desired tolerances. The preliminary action is built into the cam mechanism design, which predetermines the precise radial displacement of each die segment throughout the forming cycle, ensuring consistent groove radius without requiring real-time operator intervention or complex control systems.
3Ease of manufacture
If circumferential grooves are impressed near the end of pipe elements, then coupling installation is enabled, but the end region of the pipe element expands in diameter causing flare
Solution Approach 1:
The die segments are configured to apply localized compressive force only at the specific region where the groove needs to be formed, rather than applying force across the entire pipe circumference. This localized action enables groove formation near pipe ends without causing widespread diametral expansion or flare in the pipe end region, as the material displacement is concentrated precisely where needed.
4Productivity
If prior art roll grooving machines are used, then grooves can be formed, but many revolutions of the pipe element are required to achieve a finished circumferential groove
Solution Approach 1:
The die segments are actuated by cam mechanisms that provide continuous radial force throughout the entire rotation cycle around the pipe element. This continuous action ensures that groove formation occurs uniformly with each pass, eliminating the need for multiple revolutions to complete the groove. The cam-driven system maintains constant engagement and material displacement, making the groove formation process efficient and complete in a single cycle.
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 achieves accurate and efficient groove formation with minimal torque, reduced operator involvement, and controlled flare, enabling faster production with improved precision and reduced diametral expansion at the pipe ends.
Implementation Method 1
One of a plurality of cam bodies are each mounted on a respective one of the gears. One of a plurality of first cam surfaces extend around a respective one of the cam bodies.
Implementation Method 2
A plurality of gears are mounted on the carriage. Each gear is rotatable relatively to the carriage about a respective gear axis. Each gear engages with the pinion.
Implementation Method 3
Cold working of pipe elements, for example, impressing a circumferential groove in a pipe element to accept a mechanical pipe coupling
Implementation Method 4
the outer roller is progressively forced toward the inner roller. The rollers have surface profiles which are impressed onto the pipe element circumference as it rotates, thereby forming a circumferential groove
Data Source
AI summary
A device for forming circumferential grooves in pipe elements uses multiple geared cam bodies mounted on a carriage which rotates about a fixed pinion. The gears engage with the pinion which causes the geared cam bodies to rotate relative to the carriage. Traction surfaces and cam surfaces on the cam bodies traverse the outer surface of the pipe element and impress a circumferential groove therein. To substantially prevent rotation of the pipe element the pitch circle diameter of the pinion equals the outer diameter of the pipe element and the pitch circle diameters of the traction surfaces equal the pitch circle diameters of the gears.