Rotary Wedge Gripping Mechanism for Compact Drilling Apparatus
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Solution Overview
Problem
Existing drilling apparatuses face challenges in compact design due to the significant volume required for axial and radial movement, making it difficult to fit on existing drilling rigs and limit the size of the pressure chamber around tool joint connections, while maintaining continuous mud circulation and rotation during connection making or breaking.
Innovation Solution
A drilling apparatus with a tool joint gripping mechanism that rotates at the same speed as the drill string, featuring wedge-shaped gripping pads and drive cylinders with internal wedge profiles, allowing radial movement and contact with the drill string, and a pressure chamber segregated into two parts for efficient operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If traditional chucks are used to grip the drill string, then gripping force is achieved, but the apparatus requires considerable axial and radial volume
Solution Approach 1:
The wedge-shaped gripping pads are nested within the drive cylinder, with the pads positioned inside the cylindrical housing. The internal wedge profile of the drive cylinder contains the pads during rotation, allowing the gripping mechanism to achieve high gripping force while minimizing the radial and axial volume of the apparatus.
Solution Approach 2:
The gripping mechanism transitions from traditional axial gripping to radial gripping through the wedge-shaped pads. The pads move radially inward to contact and grip the drill string, changing the dimension of gripping action from axial to radial, which reduces the axial volume requirement while maintaining effective gripping force.
2Ease of operation
If the pressure chamber is made large enough to accommodate traditional gripping mechanisms, then gripping function is achieved, but the apparatus cannot fit on existing drilling rigs
Solution Approach 1:
The drive cylinder with internal wedge profile contains the wedge-shaped gripping pads within its volume. This nested arrangement allows the gripping mechanism to be housed in a compact cylindrical space, reducing the overall height and radial dimensions of the apparatus so it can fit on existing drilling rigs while maintaining full gripping functionality.
Solution Approach 2:
The gripping pads are designed to move dynamically during rotation, with the wedge shape allowing them to engage and disengage from the drill string through radial movement. This dynamic mechanism enables the gripping function to be achieved in a compact space, as the pads only occupy the necessary volume during active gripping rather than requiring constant large space.
3Volume of moving object
If wedge-shaped gripping pads are used with internal wedge profile, then radial movement is achieved with compact design, but precise control of pad movement is required
Solution Approach 1:
The wedge-shaped gripping pads utilize the internal wedge profile of the drive cylinder to generate their own radial movement through rotation. The wedge geometry converts the rotational motion into radial gripping force automatically, without requiring external control mechanisms. This self-service mechanism simplifies the control system while achieving precise radial movement of the pads.
Solution Approach 2:
The system uses hydraulic or pneumatic pressure within the drive cylinder to control the radial movement of the wedge-shaped pads. By applying pressure differential through the wedge profile, the system achieves precise control of pad engagement and disengagement, allowing compact design while maintaining controlled gripping action through fluid pressure rather than complex mechanical controls.
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
Enables continuous circulation and rotation during drill string connections, reduces the size and weight of the pressure chamber, and halves the snubbing force, allowing for a more compact and efficient drilling apparatus that can fit on various rigs and maintain high torque for making and breaking connections.
Implementation Method 1
drive cylinders with internal wedge profiles, allowing radial movement and contact with the drill string
Data Source
AI summary
A drilling apparatus (1) is for use on a rotary drilling rig with a top drive which enables circulation and rotation of a drill string (3) to continue uninterrupted during the making of drill string connections. It has a snubber gripping mechanism (10, 9) to enable tool joints (2, 3) to be supported and gripped with a reduced pressure chamber (5) volume and snubbing force, during tool joint connections. The gripping mechanism has gripping pads (14) arranged to move radially by relative rotation of a drive cylinder (34) causing a tapered surface (36) of the drive cylinder (34) to press against or release the pad (14). A guide cylinder (30) supports and guides the pads (14) and collets (13) for retaining a drill string at an upset shoulder (19).