Pipe Handling Link Arm Torque Limiting Breakaway

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Solution Overview

Problem

In pipe handling devices for drilling or lining a wellbore, the risk of uncontrolled rotation of link arms due to seized bearings poses significant safety concerns, as the existing systems lack effective mechanisms to prevent such rotation and maintain stability during operational failures.

Innovation Solution

A pipe handling assembly with a connection between the link arm and the pipe engaging apparatus that acts as a torque limiting breakaway mechanism, such as a fusible or shearable connection, to prevent the link arm from rotating with the pipe gripping mechanism in case of bearing seizure, ensuring the link arm remains secured to the main housing and preventing uncontrolled swinging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a bearing is positioned between the link arms and the pipe gripping mechanism to permit rotational isolation, then the link arms can be isolated from rotation during normal operation, but the bearing may seize and cause uncontrolled rotation of the link arms

Engineering Contradiction:

Improverotational isolation of link armsVSAvoidbearing seizure risk

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent applies beforehand cushioning by providing a torque limiting connection between the link arm and pipe engaging apparatus that can fail safely. This connection is designed to break away when excessive torque is applied, preventing the bearing seizure from causing uncontrolled rotation. The torque limiting connection acts as a pre-planned safety mechanism that sacrifices itself to protect the overall system.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The torque limiting connection serves as an intermediary element between the link arm and the pipe engaging apparatus. It mediates the torque transmission, allowing normal operation while preventing catastrophic failure. When the bearing seizes, the torque limiting connection breaks away, isolating the link arm from the rotational force and preventing uncontrolled rotation.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Stability of the object's composition

If the link arms are isolated from rotation by a bearing, then they can hold and position the pipe stably, but the isolation may fail and cause uncontrolled swinging of the link arms

Engineering Contradiction:

Improvepositioning stability of link armsVSAvoiduncontrolled swinging hazard

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The torque limiting connection provides beforehand cushioning against the harmful effect of uncontrolled swinging. It is designed to fail at a predetermined torque level, creating a safety mechanism that activates before catastrophic failure can occur. This ensures that if the bearing fails, the link arms cannot swing uncontrollably.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent converts the potential harm of bearing failure into a beneficial safety feature. The torque limiting connection is designed to fail in a controlled manner, transforming the harmful uncontrolled rotation into a benign failure mode where the link arms simply disconnect rather than swing uncontrollably, thereby protecting personnel and equipment.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If a torque limiting breakaway connection is added to prevent uncontrolled rotation, then safety is enhanced, but the device complexity increases

Engineering Contradiction:

Improvesafety against uncontrolled rotationVSAvoidadditional connection mechanism

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The torque limiting connection is merged with the existing structural elements of the pipe engaging apparatus. Rather than being a separate, complex device, it is integrated into the connection between the link arm and the apparatus, utilizing existing components in a dual-purpose manner. This reduces the added complexity while maintaining the safety function.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The torque limiting connection serves multiple functions: it transmits torque during normal operation, limits excessive torque, and provides a safe failure mode. This multi-functionality reduces the need for additional dedicated safety components, thereby minimizing the increase in device complexity while enhancing safety.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS8037932B2Pipe handling device and safety mechanism

Publication Date: 2011.10.18 NABORS DRILLING TECHNOLOGIES USA INC

AI summary

A pipe handling assembly includes a pipe engaging apparatus having a pipe gripping mechanism connectable to a top drive such that the top drive transmits rotational movement and axial movement to the pipe gripping mechanism. A pipe handling device is mounted onto the pipe engaging apparatus, the pipe handling device including a link hanger mounted on the pipe engaging apparatus. A link arm has a first end pivotally connectable to the link hanger and an outboard end selected to carry a pipe into a position to be gripped by the pipe engaging apparatus. A bearing isolates rotational movement to the pipe gripping mechanism from the link hanger. A connection rigidly connects the link hanger to the pipe engaging apparatus during operation of the pipe handling assembly. The connection is selected to substantially prevent the link hanger from rotating with the pipe gripping mechanism should the bearing seize.