Downhole Shear Release Mechanism with Floating Nut Recess
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Solution Overview
Problem
Shear release mechanisms in downhole tools often cause jamming or scoring due to bending failures at the shear plane instead of pure shearing, leading to potential damage and operational issues.
Innovation Solution
A downhole tool design featuring a housing, a movable member, a release member, and a floating nut secured within a recess, where the nut is radially movable and optionally fixed rotationally, ensuring a defined shear plane and minimizing bending moments, with an optional displacement arrangement using a magnetic field to manage the sheared components and prevent damage or loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional shear release mechanism is used, then the mechanism can allow actions to occur only when desired using threshold forces, but it causes jamming or scoring due to bending failures at the shear plane instead of pure shearing
Solution Approach 1:
The patent applies local quality by creating a specialized recess structure in the movable member that provides a defined shear plane with specific geometric characteristics. The recess has a bottom surface that forms the shear plane and side surfaces that constrain the sheared portion, creating localized conditions that promote pure shearing failure rather than bending. This localized geometric modification ensures consistent shear behavior at the critical failure point.
Solution Approach 2:
The patent implements preliminary action by pre-forming the recess structure in the movable member before operation. The recess is already shaped with the correct geometry to receive and contain the sheared portion of the release member. This pre-prepared structure ensures that when shearing occurs, the geometry is already optimized to prevent bending and scoring, eliminating the need for post-failure adjustments or corrections.
2Ease of operation
If the release member is sheared to allow movable member movement, then the threshold force condition is met, but bending moments cause the sheared portion to damage the housing or cause jamming
Solution Approach 1:
The patent uses the recess as an intermediary structure between the release member and the housing. The recess acts as a mediator that receives the sheared portion of the release member and provides a controlled environment for the shearing process. By containing the sheared portion within the recess boundaries, the intermediary structure prevents direct contact between the sheared material and the housing, thereby preventing damage while allowing the release operation to proceed.
Solution Approach 2:
The recess structure creates a localized zone with specific geometric properties that promote pure shearing. The bottom surface of the recess provides a flat, defined shear plane, while the side surfaces provide lateral constraints. This localized geometric modification ensures that bending moments are minimized and that the shearing process occurs in a controlled manner that protects component integrity.
3Manufacturing precision
If the floating nut is made radially movable in the recess, then the shear plane is well-defined and bending moments are minimized, but the device complexity increases
Solution Approach 1:
The patent applies dynamics by making the floating nut radially movable within the recess rather than fixed in position. This dynamic capability allows the nut to adjust its radial position to accommodate variations in shear plane geometry and loading conditions. The radial movability provides adaptability while maintaining a well-defined shear plane, and the complexity is managed through the use of a simple recess structure rather than complex adjustment mechanisms.
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 design ensures a clean shear operation, reducing the risk of jamming and scoring, and effectively manages the separation of tool components to prevent damage to the housing and maintain operational integrity.
Implementation Method 1
release member (16) extending between the housing (12) and the movable member (14), a floating nut (18) secured to the shear member and movably received in a recess (20) within the movable member (14)
Data Source
AI summary
A downhole tool including a housing, a movable member movably disposed relative to the housing, a release member extending between the housing and the movable member, a floating nut secured to the shear member and movably received in a recess in the movable member.