Threaded Actuator Ratchet Assembly for Low-Torque Break-Free
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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 require high torque to break free from limit positions, 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 through tracks in the ratchet, allowing the nut to move along the shaft while blocking further rotation, enabling non-jamming operation and facilitating movement to a limit position with full motor torque while allowing break-free with relatively low torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing actuator systems are used to reach limit positions, then full motor torque can be applied, but the system jams and requires high torque to break free
Solution Approach 1:
The ratchet mechanism transitions from a static locking position to a dynamic engaged position. During normal operation, the ratchet rotates freely with the shaft. When the nut reaches the limit position, the ratchet automatically engages with the nut's shoulder, creating a dynamic transition that prevents jamming while maintaining full torque capability.
Solution Approach 2:
The ratchet acts as an intermediary element between the threaded shaft and the threaded nut. It mediates the interaction by allowing free rotation during normal operation and automatically engaging to prevent further rotation when the limit position is reached, eliminating the need for high break-free torque.
2Ease of operation
If the threaded nut is constrained to block rotation at limit position, then further rotation is prevented, but the system may jam requiring high torque to break free
Solution Approach 1:
The ratchet mechanism provides dynamic constraint rather than static blocking. During normal operation, the ratchet rotates freely with minimal resistance. When the nut reaches the limit position, the ratchet automatically engages with the nut's shoulder, creating a smooth transition to the constrained state without jamming.
Solution Approach 2:
The ratchet mechanism is self-actuating and automatically engages with the nut's shoulder when the limit position is reached, without requiring external control or high force intervention. The geometry of the ratchet and nut shoulder ensures automatic engagement and disengagement based on the rotational position.
3Adaptability or versatility
If the ratchet is positioned about the threaded shaft, then the nut can move along the shaft, but the ratchet must be prevented from rotating in the wrong direction
Solution Approach 1:
The ratchet mechanism utilizes asymmetric geometry to control rotation direction. The ratchet teeth are configured to allow rotation in the direction of nut advancement while preventing rotation in the opposite direction. This asymmetric design enables the nut to move freely along the shaft while automatically preventing reverse rotation of the ratchet.
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 actuator assembly provides a non-jamming operation, allowing the threaded nut to move to a limit position and hold full motor torque while breaking free with less than full motor torque, enhancing operational efficiency and reducing the risk of damage.
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).