Dumbell Roller Assembly for Power Tong Load Transfer
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Solution Overview
Problem
Prior art tong units experience undesirable wear and binding issues due to the direct contact between ring gear teeth and dumbell roller horizontal surfaces, and the dumbell roller shaft support system is prone to over-tightening and under-tightening, leading to binding or wear, respectively.
Innovation Solution
The implementation of dumbell rollers with both vertical and angled circumferential load support surfaces that mate with the ring gear, and a dumbell roller shaft support system featuring reduced diameter sections and threaded sections with keeper members to prevent binding and rotation, ensuring secure and wear-resistant assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the ring gear teeth directly contact the horizontal surface of the dumbell roller, then vertical load support is achieved, but wear occurs on the ring gear teeth and dumbell rollers
Solution Approach 1:
The patent introduces angled load support surfaces on the dumbell roller that act as an intermediary between the ring gear teeth and the roller body. These angled surfaces distribute the contact forces across a larger area and reduce direct point-contact wear, allowing the roller to support vertical loads while minimizing wear on both the ring gear teeth and roller surfaces.
Solution Approach 2:
The patent transitions from a purely horizontal load support surface to a combination of vertical and angled surfaces. By adding the angular dimension to the load support geometry, the system achieves both vertical load support and reduced wear through proper force distribution across multiple surface orientations.
2Stability of the object's composition
If the dumbell roller shaft is tightly secured to prevent rotation, then rotational stability is improved, but binding occurs
Solution Approach 1:
The patent applies different degrees of constraint to different sections of the shaft. The reduced diameter sections are free to rotate and accommodate thermal expansion, while the threaded sections with keeper members provide rotational stability. This localized differentiation of constraints prevents binding while maintaining necessary stability.
Solution Approach 2:
The shaft is segmented into different functional zones: reduced diameter sections for rotation and thermal movement, and threaded sections for securing. The keeper members are positioned at specific segments to prevent over-tightening. This segmentation allows each section to perform its specific function without causing binding elsewhere in the system.
3Ease of operation
If the dumbell roller shaft is loosely secured to allow movement, then binding is prevented, but wear occurs
Solution Approach 1:
The keeper members act as intermediaries between the shaft and the roller support structure. They provide a controlled interface that prevents excessive movement and wear while allowing sufficient freedom to prevent binding. The keeper members mediate the relationship between the shaft sections, enabling easy removal for maintenance while preventing harmful wear.
4Ease of manufacture
If the shaft is designed with uniform diameter, then manufacturing is simplified, but over-tightening and under-tightening lead to binding or wear
Solution Approach 1:
The patent applies different diameters to different sections of the shaft. The reduced diameter sections facilitate easy passage through bearing holes and prevent binding, while the threaded sections with larger diameter provide secure anchoring. This local differentiation of dimensions solves the reliability issues while maintaining manufacturing feasibility through standardized section designs.
Data Source
AI summary
A power tong having a ring gear and dumbell rollers, with mating load surfaces on the ring gear and dumbell rollers which transfer horizontal and vertical loads from the ring gear to the dumbell rollers, without contact between the ring gear teeth and the dumbell rollers. The power tong further has a dumbell roller shaft configuration which permits vertical and rotational locking of the shaft, while permitting easy replacement and without binding of the rotation of the top and bottom plates on the dumbell rollers.