Threaded Actuator Ratchet Assembly for Low-Torque Limit Release
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Solution Overview
Problem
Existing actuator systems in mineral extraction systems, such as those used in drilling and production systems, face issues with jamming and high torque requirements when operating fluid-handling components like valves, which can lead to inefficient operation and potential damage.
Innovation Solution
The actuator assembly includes a threaded shaft, a threaded nut, an annular ratchet, and a pin that extends into tracks on the ratchet, allowing for controlled rotation and movement of the nut along the shaft while blocking further rotation, thereby preventing jamming and reducing torque requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional actuator system is used to operate fluid-handling components, then the valve can be actuated between open and closed positions, but the system experiences jamming and high torque requirements
Solution Approach 1:
The actuator assembly is divided into distinct functional segments: a threaded shaft for rotational input, a threaded nut for linear conversion, and an annular ratchet with tracks for controlled movement. This segmentation allows each component to perform its specific function efficiently, preventing jamming by ensuring smooth transitions between rotational and linear motion phases.
Solution Approach 2:
The annular ratchet acts as an intermediary mechanism between the threaded shaft and the threaded nut. The pin extending from the shaft into the tracks provides controlled engagement, mediating the force transmission and preventing direct contact that could cause jamming. This intermediary structure distributes forces evenly and eliminates high-torque stress points.
2Manufacturing precision
If the threaded shaft rotates continuously to move the nut, then the actuation process is simple, but the nut cannot be positioned precisely at the limit position
Solution Approach 1:
The actuation mechanism transitions from continuous rotation to controlled engagement through the annular ratchet. During normal operation, the shaft rotates freely to move the nut along its path. At the limit position, the pin engages with the ratchet tracks, dynamically changing the system from free rotation to constrained movement, enabling precise positioning without requiring complex feedback mechanisms.
Solution Approach 2:
The annular ratchet with tracks and pin creates a self-limiting mechanism. As the shaft rotates and moves the nut toward the limit position, the geometric constraints of the ratchet tracks automatically engage the pin, stopping further rotation and positioning the nut precisely without external control input. The system self-regulates its own movement limits.
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 configuration enables non-jamming operation and allows the actuator assembly to hold full motor torque while breaking free from the limit position with relatively low torque, improving the efficiency and reliability of fluid-handling components in mineral extraction systems.
Implementation Method 1
a threaded shaft, a threaded nut that is threadably coupled to the threaded shaft
Implementation Method 2
an annular ratchet positioned about the threaded shaft and comprising one or more tracks, and a pin that extends from the threaded shaft and into the one or more tracks
Data Source
AI summary
An actuator assembly includes a threaded shaft, a threaded nut that is threadably coupled to the threaded shaft, an annular ratchet positioned about the threaded shaft and comprising one or more tracks, and a pin that extends from the threaded shaft and into the one or more tracks. The threaded nut may include a first circumferentially-facing surface, the annular ratchet may include a second circumferentially-facing surface, and the first and second circumferentially-facing surfaces are configured to contact one another to enable the threaded nut to block rotation of the annular ratchet with the threaded shaft. The actuator assembly may enable the threaded nut to move to a limit position and hold full motor torque, but also to break free from the limit position with relatively low torque (e.g., less than the full motor torque; as compared to actuator systems that are devoid of certain features of the actuator assembly).